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Stem Cell Basics A Closer Look at Stem Cells

About stem cells

Stem cells are the foundation of development in plants, animals and humans. In humans, there are many different types of stem cells that come from different places in the body or are formed at different times in our lives. These include embryonic stem cells that exist only at the earliest stages of development and various types oftissue-specific(oradult)stem cells that appear during fetal development and remain in our bodies throughout life.Stem cells are defined by two characteristics:

Beyond these two things, though, stem cells differ a great deal in their behaviors and capabilities.

Embryonic stem cells arepluripotent, meaning they can generate all of the bodys cell types but cannot generate support structures like the placenta and umbilical cord.

Other cells aremultipotent,meaning they can generate a few different cell types, generally in a specific tissue or organ.

As the body develops and ages, the number and type of stem cells changes. Totipotent cells are no longer present after dividing into the cells that generate the placenta and umbilical cord. Pluripotent cells give rise to the specialized cells that make up the bodys organs and tissues. The stem cells that stay in your body throughout your life are tissue-specific, and there is evidence that these cells change as you age, too your skin stem cells at age 20 wont be exactly the same as your skin stem cells at age 80.

Learn more about different types of stem cellshere.

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Stem Cell Basics A Closer Look at Stem Cells

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TREATMENTS – IMAGE NOW. Age later.

Our signature chemical peels help to reverse the visible effects of damage in two ways. First, they power away dull, dead cells to illuminate the skin and reduce the appearance of fine lines, wrinkles, age spots, clogged pores and blemishes. Then, they support collagen for firmer-looking skin over time. Ask your esthetician which IMAGE chemical peel will best target your skins individual needs.

I PEEL | WRINKLE LIFT

Ultra-resurfacing blend of glycolic acid combined with retinol to visibly reduce the appearance of fine lines and wrinkles.

Skin type indications: Aging, wrinkles, rough complexion, uneven skin tone, smokers skin, tired/dull skin, oily/acne

I PEEL | WRINKLE LIFT FORTE

This advanced treatment is formulated with additional glycolic acid and an innovative blend of firming and anti-aging properties, to visibly reduce the appearance of fine lines and wrinkles.

Skin type indications: Advanced aging, wrinkles, rough complexion, uneven skin tone, smokers skin, tired/dull skin, oily/acne

I PEEL | PERFECTION LIFT

This distinct blend of active exfoliants works synergistically to visibly reduce the appearance of fine lines, correct uneven skin tone, smooth rough texture and reduce acne blemishes.

Skin type indications: Aging, pigmentation, acne

I PEEL | PERFECTION LIFT FORTE

This concentrated blend of lactic acid, salicylic acid and resorcinol works synergistically to quickly and effectively reduce the appearance of advanced aging, pigmentation and acne. This extra strength treatment reveals a younger you in a single treatment.

Skin type indications: Advanced aging, pigmentation, acne

I PEEL | ACNE LIFT

Blend of AHAs and BHAs with protective agents to effectively treat all grades of acne.

Acne, oily, acne-prone, aging

I PEEL | BETA LIFT

This powerful non-blended salicylic acid treatment quickly and effectively targets and improves moderate/severe acne. Skin type indications: Acne, oily, aging

I PEEL | LIGHTENING LIFT

Lactic acid blended with kojic acid and a cocktail of brightening agents to reduce all forms of pigmentation.

Skin type indications: Pigmentation, aging, dry/dehydrated, uneven skin tone, age spots, redness-prone

I PEEL | LIGHTENING LIFT FORTE

This results-driven treatment combines the most innovative and effective botanical brighteners with echinacea, plant-derived stem cells and anti-aging peptides for youthful, illuminated skin.

Skin type indications: Advanced pigmentation, aging, dry/dehydrated, uneven skin tone, age spots, redness-prone

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TREATMENTS - IMAGE NOW. Age later.

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Types of Stem Cells A Closer Look at Stem Cells

Tissue-specific stem cells

Tissue-specific stem cells (also referred to assomaticoradultstem cells) are more specialized than embryonic stem cells. Typically, these stem cells can generate different cell types for the specific tissue or organ in which they live.

For example, blood-forming (orhematopoietic) stem cells in the bone marrow can give rise to red blood cells, white blood cells and platelets. However, blood-forming stem cells dont generate liver or lung or brain cells, and stem cells in other tissues and organs dont generate red or white blood cells or platelets.

Some tissues and organs within your body contain small caches of tissue-specific stem cells whose job it is to replace cells from that tissue that are lost in normal day-to-day living or in injury, such as those in your skin, blood, and the lining of your gut.

Tissue-specific stem cells can be difficult to find in the human body, and they dont seem to self-renew in culture as easily as embryonic stem cells do. However, study of these cells has increased our general knowledge about normal development, what changes in aging, and what happens with injury and disease.

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Types of Stem Cells A Closer Look at Stem Cells

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Non-Functioning Tumors (Endocrine-Inactive Tumors …

As their name indicates, these relatively common pituitary adenomas do not result in excess hormone production. Instead they typically cause symptoms because of increasing size and pressure effect on the normal pituitary gland and on structures near the pituitary such as the optic nerves and chiasm. The major symptoms of patients with endocrine-inactive tumors are those of pituitary failure (hypopituitarism), visual loss and headache. Hypopituitarism may manifest itself as nausea, vomiting, weakness, decreased mental function, loss of sexual drive, infertility and in women, irregular or absent periods (amenorrhea). The vast majority of these tumors are benign. Most are macroadenomas (over 1 cm in size) when finally diagnosed. Occasionally, they grow quite large and into the cavernous sinus causing nerve compression and double vision. Some patients with large tumors may have acute hemorrhage into the tumor (pituitary apoplexy) causing relatively sudden onset of headache, visual loss, double vision, and/or pituitary failure. Endocrine-inactive adenomas may also be discovered incidentally during an evaluation for another problem, such as a head injury. Almost half of endocrine-inactive adenomas secrete part of a hormone called the alpha-subunit, which is not hormonally active but can be measured in the blood.

In patients with symptoms suggestive of pituitary failure (hypopituitarism), a complete endocrinological evaluation should be performed. These blood tests should include:

Based on the results of these tests, additional hormonal studies may be ordered.

For patients with visual complaints, an ophthalmologist (preferably a neuro-ophthalmologist should evaluate the patient. This evaluation should include acuity testing of each eye and formal visual field testing to determine if there is loss of peripheral vision.

An MRI of the pituitary without and with gadolinium (contrast agent) is the preferred study for visualizing a pituitary tumor. In most instances, a CT scan without and with contrast will also detect an adenoma. In a minority of cases instances it may be difficult to distinguish an adenoma of the pituitary from other masses. These masses include:

For the great majority of patients with symptomatic endocrine-inactive adenomas, transsphenoidal surgery and adenoma removal is the preferred and most effective therapy. The long-term cure or control rate is approximately 70-80% overall. The cure rate is generally higher for smaller tumors and those that do not invade the cavernous sinus; conversely, the cure rate is lower for larger tumors (over 3 cm) and those that do invade the cavernous sinus. Overall, transsphenoidal tumor resection results in an improvement in visual acuity and visual field deficits in 75-90% of patients, headache resolution in 80-90% of patients, and improvement in hypopituitarism in only 10-30% of patients. Patients who do not have hormonal recovery after surgery will require long-term hormone replacement therapy. Because the transsphenoidal approach is so effective and relatively safe, it is rare that even large macroadenomas warrant a transcranial operation as the initial procedure.

There is no known effective medical therapy that reliably slows or stops growth of endocrine inactive adenomas.

Radiation is generally used as a second line therapy for endocrine-inactive tumors. For patients who have residual tumor after the initial surgery, radiation or repeat transsphenoidal surgery or both are generally indicated if the tumor grows as seen on subsequent MRIs. Both conventional (external beam) and stereotactic radiosurgery are relatively effective in controlling growth, but stereotactic radiation can deliver a higher radiation dose to the tumor more safely. Consequently it is the preferred radiation technique. Also, external beam radiation reliably causes loss of remaining normal pituitary function over 5 to 10 years. Stereotactic radiosurgery may also cause loss of pituitary function, but less frequently then external beam radiation.

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AnteAge Stem Cell Skin Care Reviewed

Serum: KEY ACTIVE INGREDIENTS:Stem CytokinesCarnosineNiacinamide (vit B3)Palmitoyl OligopeptidePalmitoyl Tetrapeptide-7Yerba MatGreenTea ExtractCatechins & Flavonoids

INGREDIENTS:Mesenchymal Stem Cell Cytokines,Water (Aqua), Palmitoyl Oligopeptide, Niacinamide (Vitamin B3), Palmitoyl Tetrapeptide-7, PPG-3 Benzyl Myristate, Dimethyl Isosorbide, Carnosine, Hydrolyzed Myrtus Communis (True Myrtle) Leaf Extract, Polyacrylate-13, Camellia Sinensis (Green Tea) Leaf Extract, Maltodextrin, Ilex Paraguariensis (Paraguay) Leaf (Yerba Mate) Extract, Cetearyl Ethylhexanoate, Polyisobutene, Phenoxyethanol (Preservative), Caprylyl Glycol (NaturallyDerived Preservative), Polysorbate-20 (Plant Derived), Chlorphenesin, TetrasodiumEDTA, Citric Acid (Naturally Derived) Accelerator: KEY ACTIVE INGREDIENTS:

INGREDIENTS: Mesenchymal Stem Cell Cytokines, Water (Aqua), Glycerin (Plant Derived), C12-15 Alkyl Benzoate, PPG-3 Benzyl Myristate, Carthamus Tinctorius (Safflower) Seed Oil, Alcohol, Cetearyl Alcohol (Plant Derived), Tocopheryl Acetate (Vitamin E Acetate), Polysorbate-20 (Plant Derived), Cetearyl Glucoside,Tetrahexyldecyl Ascorbate (Vitamin C Ester), Simmondsia Chinensis (Jojoba) Seed Oil, Limnanthes Alba (Meadowfoam) Seed Oil, Dimethyl Isosorbide, Butylene Glycol, Polysorbate-60 (Plant Derived), Glyceryl Stearate (Plant Derived),Lecithin, Hydroxyethyl Acrylate/Sodium Acryloyl Dimethyl Taurate Copolymer, SoybeanGlycerides, Arachidyl Alcohol, Soy Isoflavones, Phenoxyethanol (Preservative), Helianthus Annuus (Hybrid Sunflower) Oil, Butyrospermum Parkii (Shea Butter) Fruit, Bisabolol,Arbutin, Caprylyl Glycol (Naturally Derived Preservative), Behenyl Alcohol, Lonicera Japonica (Honeysuckle) Extract (Natural Preservative), Foeniculum Vulgare (Fennel) Fruit Extract, Camellia Oleifera (ORGANIC) Black Tea, Algae (Seaweed) Extract,Xanthan Gum (Natural Thickener), Saccharum Officinarum (Sugar Cane), Chlorphenesin, Squalane (Plant Derived), Retinol (Vitamin A), Ubiquinone (Coenzyme Q10), Panthenol (Pro-Vitamin B5), Allantoin (Comfrey Root Derived), Citrus MedicaLimonum (Lemon) Fruit Extract, Citrus Aurantium Dulcis (Sweet Neroli Orange) Fruit, Tetrasodium EDTA, Pyrus Malus (Apple) Fruit Juice, Sodium Hyaluronate, Camellia Sinensis (Green Tea) Leaf Extract, Arachidyl Glucoside, Vitis Vinifera (Grape) SeedExtract, Salix Alba (Willow) Bark Extract, Vaccinium Myrtillus (Bilberry) Extract, Phyllanthus Emblica (Amla) Extract, Thioctic Acid (a-Lipoic Acid), Sodium Hydroxide (pH Modifier)

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AnteAge Stem Cell Skin Care Reviewed

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Icelanders – Wikipedia

This article is about Icelanders as an ethnic group. For information about residents or nationals of Iceland, see Demographics of Iceland.IcelandersslendingarTotal population383,500[1]465,000Regions with significant populationsIceland 295,672[2]Canada94,205[3]United States42,716[4]Denmark8,429[5]Norway8,274[5]Sweden5,454[5]United Kingdom2,225[5]Germany1,802[5]Spain1,122[5]Australia980[6]Brazil576[5]Poland492[5]Other countries combinedc.3,000[5]LanguagesIcelandicReligionLutheranism (mainly the Church of Iceland);[7] Neo-pagan; Roman Catholic and Eastern Orthodox minorities among other faiths; secular. Historically Norse paganism, Celtic Christianity (c. 1000) and Catholicism (c. 1000 1551). See Religion in IcelandRelated ethnic groupsOther Germanic peoples, especially Norwegians, Danes, Faroese Islanders

Icelanders (Icelandic: slendingar) are a North Germanic ethnic group and nation who are native to the island nation of Iceland and speak Icelandic.[8]

Icelanders established the country of Iceland in 930 A.D. when the Althingi (Parliament) met for the first time. Iceland came under the reign of Norwegian, Swedish and Danish kings but regained full sovereignty and independence from the Danish monarchy on 1 December 1918, when the Kingdom of Iceland was established. On 17 June 1944, the monarchy was abolished and the Icelandic republic was founded. The language spoken is Icelandic, a North Germanic language, and Lutheranism is the predominant religion. Historical and DNA records indicate that around 60 to 80 percent of the male settlers were of Norse origin (primarily from Western Norway) and a similar percentage of the women were of Gaelic stock from Ireland and peripheral Scotland.[9][10]

Icelanders have had a tumultuous history. Development of the island was slow due to a lack of interest from the countries controlling it for most of its history: Norway, DenmarkNorway, and ultimately Denmark. Through this time, Iceland had relatively little contact with the outside world.[11] The island became independent in personal union with the Kingdom of Denmark in 1918. Since 1944, Iceland has been a republic, and Icelandic society has undergone a rapid modernisation process in the post-independence era.

Iceland is a geologically young land mass, having formed an estimated 20 million years ago due to volcanic eruptions on the Mid-Atlantic ridge. One of the last larger islands to remain uninhabited, the first human settlement date is generally accepted to be 874 AD, although there is some evidence to suggest human activity prior to the Norse arrival.[12]

The first Viking to sight Iceland was Gardar Svavarsson, who went off course due to harsh conditions when sailing from Norway to the Faroe Islands. His reports led to the first efforts to settle the island. Flki Vilgerarson (b. 9th century) was the first Norseman to sail to Iceland intentionally. His story is documented in the Landnmabk manuscript, and he is said to have named the island sland (Iceland). The first permanent settler in Iceland is usually considered to have been a Norwegian chieftain named Inglfur Arnarson. He settled with his family in around 874, at a place he named "Bay of Smokes", or Reykjavk in Icelandic.[13]

Following Inglfur, and also in 874, another group of Norwegians set sail across the North Atlantic Ocean with their families, livestock, slaves, and possessions, escaping the domination of the first King of Norway, Harald Fairhair. They traveled 1,000km (600mi) in their Viking longships to the island of Iceland. These people were primarily of Norwegian, Irish or Gaelic Scottish origin. The Irish and the Scottish Gaels were either slaves or servants of the Norse chiefs, according to the Icelandic sagas, or descendants of a "group of Norsemen who had settled in Scotland and Ireland and intermarried with Gaelic-speaking people".[14] Genetic evidence suggests that approximately 62% of the Icelandic maternal gene pool is derived from Ireland and Scotland, which is much higher than other Scandinavian countries, although comparable to the Faroese, while 37% is of Nordic origin.[15] About 20-25% of the Icelandic paternal gene pool is of Gaelic origin, with the rest being Nordic.[16]

The Icelandic Age of Settlement (Icelandic: Landnmsld) is considered to have lasted from 874 to 930, at which point most of the island had been claimed and the Alingi (English: Althing), the assembly of the Icelandic Commonwealth, was founded at ingvellir.[17]

In 930, on the ingvellir (English: Thingvellir) plain near Reykjavk, the chieftains and their families met and established the Alingi, Iceland's first national assembly. However, the Alingi lacked the power to enforce the laws it made. In 1262, struggles between rival chieftains left Iceland so divided that King Haakon IV of Norway was asked to step in as a final arbitrator for all disputes, as part of the Old Covenant. This is known as the Age of the Sturlungs.[18]

Iceland was under Norwegian leadership until 1380, when the Royal House of Norway died out. At this point, both Iceland and Norway came under the control of the Danish Crown. With the introduction of absolute monarchy in Denmark, the Icelanders relinquished their autonomy to the crown, including the right to initiate and consent to legislation. This meant a loss of independence for Iceland, which led to nearly 300 years of decline: perhaps largely because Denmark and its Crown did not consider Iceland to be a colony to be supported and assisted. In particular, the lack of help in defense led to constant raids by marauding pirates along the Icelandic coasts.[11]

Unlike Norway, Denmark did not need Iceland's fish and homespun wool. This created a dramatic deficit in Iceland's trade, and no new ships were built as a result. In 1602 Iceland was forbidden to trade with other countries by order of the Danish Government, and in the 18th century climatic conditions had reached an all-time low since Settlement.[11]

In 178384 Laki, a volcanic fissure in the south of the island, erupted. The eruption produced about 15km (3.6mi) of basalt lava, and the total volume of tephra emitted was 0.91km.[19] The aerosols that built up caused a cooling effect in the Northern Hemisphere. The consequences for Iceland were catastrophic, with approximately 25-33% of the population dying in the famine of 1783 and 1784. Around 80% of sheep, 50% of cattle, and 50% of horses died of fluorosis from the 8 million tons of fluorine that were released.[20] This disaster is known as the Mist Hardship (Icelandic: Muharindin).

In 179899 the Alingi was discontinued for several decades, eventually being restored in 1844. It was moved to Reykjavk, the capital, after being held at ingvellir for over nine centuries.

The 19th century brought significant improvement in the Icelanders' situation. A protest movement was led by Jn Sigursson, a statesman, historian, and authority on Icelandic literature. Inspired by the romantic and nationalist currents from mainland Europe, Jn protested strongly, through political journals and self-publications, for 'a return to national consciousness' and for political and social changes to be made to help speed up Iceland's development.[21]

In 1854, the Danish government relaxed the trade ban that had been imposed in 1602, and Iceland gradually began to rejoin Western Europe economically and socially. With this return of contact with other peoples came a reawakening of Iceland's arts, especially its literature. Twenty years later in 1874, Iceland was granted a constitution. Icelanders today recognize Jn's efforts as largely responsible for their economic and social resurgence.[21]

Iceland gained full sovereignty and independence from Denmark in 1918 after World War I. It became the Kingdom of Iceland. The King of Denmark also served as the King of Iceland but Iceland retained only formal ties with the Danish Crown. On 17 June 1944 the monarchy was abolished and a republic was established on what would have been Jn Sigursson's 133rd birthday. This ended nearly six centuries of ties with Denmark.[21]

Due to their small founding population and history of relative isolation, Icelanders have often been considered highly genetically homogeneous as compared to other European populations. For this reason, along with the extensive genealogical records for much of the population that reach back to the settlement of Iceland, Icelanders have been the focus of considerable genomics research by both biotechnology companies and academic and medical researchers.[22][23] It was, for example, possible for researchers to reconstruct much of the maternal genome of Iceland's first known black inhabitant, Hans Jonatan, from the DNA of his present-day descendants partly because the distinctively African parts of his genome were unique in Iceland until very recent times.[24]

Genetic evidence shows that most DNA lineages found among Icelanders today can be traced to the settlement of Iceland, indicating that there has been relatively little immigration since. This evidence shows that the founder population of Iceland came from Ireland, Scotland, and Scandinavia: studies of mitochondrial DNA and Y-chromosomes indicate that 62% of Icelanders' matrilineal ancestry derives from Scotland and Ireland (with most of the rest being from Scandinavia), while 75% of their patrilineal ancestry derives from Scandinavia (with most of the rest being from the Irish and British Isles).[25] Despite Iceland's historical isolation, the genetic makeup of Icelanders today is still quite different from the founding population, due to founder effects and genetic drift.[26] One study found that the mean Norse ancestry among Iceland's settlers was 56%, whereas in the current population the figure was 70%.[27]

Other studies have identified other ancestries, however. One study of mitochondrial DNA, blood groups, and isozymes revealed a more variable population than expected, comparable to the diversity of some other Europeans.[28] Another study showed that a tiny proportion of samples of contemporary Icelanders carry a more distant lineage, which belongs to the haplogroup C1e, which can possibly be traced to the settlement of the Americas around 14,000 years ago. This hints a small proportion of Icelanders have some Native American ancestry arising from Norse colonization of Greenland and North America.[29]

The first Europeans to emigrate to and settle in Greenland were Icelanders who did so under the leadership of Erik the Red in the late 10th century CE and numbered around 500 people. Isolated fjords in this harsh land offered sufficient grazing to support cattle and sheep, though the climate was too cold for cereal crops. Royal trade ships from Norway occasionally went to Greenland to trade for walrus tusks and falcons. The population eventually reached a high point of perhaps 3,000 in two communities and developed independent institutions before fading away during the 15th century.[30] A papal legation was sent there as late as 1492, the year Columbus attempted to find a shorter spice route to Asia but instead encountered the Americas.

According to the Saga of Eric the Red, Icelandic immigration to North America dates back to Vinland circa 1006. The colony was believed to be short-lived and abandoned by the 1020s. [31] European settlement of the region was not archeologically and historically confirmed as more than legend until the 1960s. The former Norse site, now known as L'Anse aux Meadows, pre-dated the arrival of Colombus in the Americas by almost 500 years.

A more recent instance of Icelandic emigration to North America occurred in 1855, when a small group settled in Spanish Fork, Utah.[32] Another Icelandic colony formed in Washington Island, Wisconsin.[33] Immigration to the United States and Canada began in earnest in the 1870s, with most migrants initially settling in the Great Lakes area. These settlers were fleeing famine and overcrowding on Iceland.[34] Today, there are sizable communities of Icelandic descent in both the United States and Canada. Gimli, in Manitoba, Canada, is home to the largest population of Icelanders outside of the main island of Iceland.[35]

From the mid-1990s, Iceland experienced rising immigration. By 2017 the population of first-generation immigrants (defined as people born abroad with both parents foreign-born and all grandparents foreign-born) stood at 35,997 (10.6% of residents), and the population of second-generation immigrants at 4,473. Correspondingly, the numbers of foreign-born people acquiring Icelandic citizenship are markedly higher than in the 1990s, standing at 703 in 2016.[36][37] Correspondingly, Icelandic identity is gradually shifting towards a more multicultural form.[38]

Icelandic, a North Germanic language, is the official language of Iceland (de facto; the laws are silent about the issue). Icelandic has inflectional grammar comparable to Latin, Ancient Greek, more closely to Old English and practically identical to Old Norse.

Old Icelandic literature can be divided into several categories. Three are best known to foreigners: Eddic poetry, skaldic poetry, and saga literature, if saga literature is understood broadly. Eddic poetry is made up of heroic and mythological poems. Poetry that praises someone is considered skaldic poetry or court poetry. Finally, saga literature is prose, ranging from pure fiction to fairly factual history.[39]

Written Icelandic has changed little since the 13th century. Because of this modern readers can understand the Icelanders' sagas. The sagas tell of events in Iceland in the 10th and early 11th centuries. They are considered to be the best-known pieces of Icelandic literature.[40]

The elder or Poetic Edda, the younger or Prose Edda, and the sagas are the major pieces of Icelandic literature. The Poetic Edda is a collection of poems and stories from the late 10th century, whereas the younger or Prose Edda is a manual of poetry that contains many stories of Norse mythology.

Iceland embraced Christianity in c. AD 1000, in what is called the kristnitaka, and the country, while mostly secular in observance, is still predominantly Christian culturally. The Lutheran church claims some 84% of the total population.[41] While early Icelandic Christianity was more lax in its observances than traditional Catholicism, Pietism, a religious movement imported from Denmark in the 18th century, had a marked effect on the island. By discouraging all but religious leisure activities, it fostered a certain dourness, which was for a long time considered an Icelandic stereotype. At the same time, it also led to a boom in printing, and Iceland today is one of the most literate societies in the world.[21][42]

While Catholicism was supplanted by Protestantism during the Reformation, most other world religions are now represented on the island: there are small Protestant Free Churches and Catholic communities, and even a nascent Muslim community, composed of both immigrants and local converts. Perhaps unique to Iceland is the fast-growing satrarflag, a legally recognized revival of the pre-Christian Nordic religion of the original settlers. According to the Roman Catholic Diocese of Reykjavk, there were only approximately 30 Jews in Iceland as of 2001.[43] The former First Lady of Iceland Dorrit Moussaieff was an Israeli-born Bukharian Jew.

Icelandic cuisine consists mainly of fish, lamb, and dairy. Fish was once the main part of an Icelander's diet but has recently given way to meats such as beef, pork, and poultry.[20]

Iceland has many traditional foods called orramatur. These foods include smoked and salted lamb, singed sheep heads, dried fish, smoked and pickled salmon, and cured shark. Andrew Zimmern, a chef who has traveled the world on his show Bizarre Foods with Andrew Zimmern, responded to the question "What's the most disgusting thing you've ever eaten?" with the response "That would have to be the fermented shark fin I had in Iceland." Fermented shark fin is a form of orramatur.[44]

The earliest indigenous Icelandic music was the rmur, epic tales from the Viking era that were often performed a cappella. Christianity played a major role in the development of Icelandic music, with many hymns being written in the local idiom. Hallgrmur Ptursson, a poet and priest, is noted for writing many of these hymns in the 17th century. The island's relative isolation ensured that the music maintained its regional flavor. It was only in the 19th century that the first pipe organs, prevalent in European religious music, first appeared on the island.[45]

Many singers, groups, and forms of music have come from Iceland. Most Icelandic music contains vibrant folk and pop traditions. Some more recent groups and singers are Voces Thules, The Sugarcubes, Bjrk, Sigur Rs, and Of Monsters and Men.

The national anthem is " Gu vors lands" (English: "Our Country's God"), written by Matthas Jochumsson, with music by Sveinbjrn Sveinbjrnsson. The song was written in 1874, when Iceland celebrated its one thousandth anniversary of settlement on the island. It was originally published with the title A Hymn in Commemoration of Iceland's Thousand Years.[45]

Iceland's men's national football team participated in their first FIFA World Cup in 2018, after reaching the quarter finals of its first major international tournament, UEFA Euro 2016. The women's national football team has yet to reach a World Cup; its best result at a major international event was a quarterfinal finish in UEFA Women's Euro 2013. The country's first Olympic participation was in the 1912 Summer Olympics; however, they did not participate again until the 1936 Summer Olympics. Their first appearance at the Winter Games was at the 1948 Winter Olympics. In 1956, Vilhjlmur Einarsson won the Olympic silver medal for the triple jump.[46] The Icelandic national handball team has enjoyed relative success. The team received a silver medal at the 2008 Olympic Games and a 3rd place at the 2010 European Men's Handball Championship.

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GNN – Genetics and Genomics Timeline

1910

Thomas Hunt Morgan (1866-1945) establishes the chromosomal theory of heredity

Thomas Hunt Morgan, an embryologist who had turned to research in heredity, in 1907 began to extensively breed the common fruit fly, Drosophila melanogaster. He hoped to discover large-scale mutations that would represent the emergence of new species. As it turned out, Morgan confirmed Mendelian laws of inheritance and the hypothesis that genes are located on chromosomes. He thereby inaugurated classical experimental genetics.

These results were suggestive for hypotheses of which Morgan himself was skeptical. He was at the time critical of the Mendelian theory of inheritance, mistrusted aspects of chromosomal theory, and did not believe that Darwin's concept of natural selection could account for the emergence of new species. But Morgan's discoveries with white- and red-eyed flies led him to reconsider each of these hypotheses.

In particular, Morgan began to entertain the possibility that association of eye color and sex in fruit flies had a physical and mechanistic basis in the chromosomes. The shape of one of Drosophila's four chromosome pairs was thought to be distinctive for sex determination. Males invariably possess the XY chromosome pair (Morgan used a more cumbersome notation) while flies with the XX chromosome are female. If the factor for eye color was located exclusively on the X chromosome, Morgan realized, Mendelian rules for inheritance of dominant and recessive traits could apply.

In brief, Morgan had discovered that eye color in Drosophila expressed a sex-linked trait. All first-generation offspring of a mutant white-eyed male and a normal red-eyed female would have red eyes because every chromosome pair would contain at least one copy of the X chromosome with the dominant trait. But half the females from this union would now possess a copy of the white-eyed male's recessive X chromosome. This chromosome would be transmitted, on average, to one-half of second-generation offspringone-half of which would be male. Thus, second-generation offspring would include one-quarter with white eyesand all of these would be male.

Intensive work led Morgan to discover more mutant traitssome two dozen between 1911 and 1914. With evidence drawn from cytology he was able to refine Mendelian laws and combine them with the theoryfirst suggested by Theodor Boveri and Walter Suttonthat the chromosomes carry hereditary information. In 1915, Morgan and his colleagues published The Mechanism of Mendelian Heredity. Its major tenets:

Discrete pairs of factors located on chromosomes like beads on a string bear hereditary information. These factorsMorgan would soon call them genessegregate in germ cells and combine during reproduction, essentially as predicted by Mendelian laws. However:

Certain characteristics are sex-linkedthat is, occur together because they arise on the same chromosome that determines gender. More generally:

Other characteristics are also sometimes associated because, as paired chromosomes separate during germ cell development, genes proximate to one another tend to remain together. But sometimes, as a mechanistic consequence of reproduction, this linkage between genes is broken, allowing for new combinations of traits.

Morgan's experimental and theoretical work inaugurated research in genetics and promoted a revolution in biology. Evidence he adduced from embryology and cell theory pointed the way toward a synthesis of genetics with evolutionary theory. Morgan himself explored aspects of these developments in later work, including Evolution and Genetics published in 1925, and The Theory of the Gene in 1926. He received the Nobel Prize in Physiology or Medicine in 1933.

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Tribal Enrollment and Genetic Testing | Genetics

By Jessica Bardill (Cherokee), PhD

When the NCAI Policy Research Center began developing this resource guide, tribal leaders asked many questions such as, What is genetic testing? What are good sources of information about genetic testing? What kinds of DNA testing can we use for tribal enrollment? How do we respond to individuals claiming tribal membership based on DNA tests? This paper was developed to provide tribal leaders with more information on genetic testing related to tribal enrollment. Tribes are sovereign nations and so will decide their own views on genetic testing. This paper provides information to assist in those decisions.

Genetic information (i.e., DNA) collected from individuals, families, and communities can be used in many different ways and it is becoming more of a discussion topic in tribal communities. While research is one possible use of genetic information, this information can also be used to examine how people are related to one another by comparing the similarity of their DNA sequences. Genetic information can also provide clues to ancestral relations. DNA is obtained by collecting biological samples (e. g., blood, hair, cells from a cheek swab, or even from spitting in a cup). Genetic testing has been advertised to tribes as a tool for determining their enrollment (TallBear 2003). Historically, tribal nations have used a variety of ways to determine their own membership. More background information on tribal determination of enrollment is available in the section entitled Tribal Sovereignty and Enrollment Determinations. This section discusses the use of genetic information in determinations of tribal enrollment. For a quick overview of relevant issues, please see this summary handout.

Types of DNA Testing and Considerations about their Use

What do people mean by DNA testing?

DNA testing has become an umbrella term that refers to many different kinds of genetic testing that provides information about an individuals genes. Genetic information, or DNA, is found in nearly every cell in the human body. DNA testing technology is constantly changing, and so are the efforts to engage tribes in testing on an individual and group basis. One type of DNA testing called DNA fingerprinting can be used to help document close biological relationships, such as those between parents and children, as well as among other close family members. Other kinds of testing for genetic ancestry use markers to see how similar an individual is to a broader population or group, based on probabilities drawn from databases of research on populations and group genetic characteristics. However, no DNA testing can prove an individual is American Indian and/or Alaska Native, or has ancestry from a specific tribe. Genetic testing can provide evidence for the biological relationship between two individuals (e.g., paternity testing), but there are no unique genes for individual tribes or American Indian/Alaska Native (AI/AN) ancestry in general. While research scientists have found that some genetic markers are found mostly only in AI/ANs, these markers are neither unique to AI/ANs nor predictive of AI/AN identity. This section will discuss various types of DNA testing as well as considerations for tribal leaders and members when engaging with testing companies.

Probability

In almost all genetic testing, information is expressed in terms of probability or a chance of something. For example, genetic testing can estimate the chance of two individuals being related, or sometimes the probability of developing a certain disease[1]. Commonly this probability or chance is expressed as a percentage of how likely something is (99.5% for example). For parentage of a child, genetic testing can provide a very accurate probability estimate. In trying to determine whether a child is related to others (grandparents, siblings, cousins, aunts and uncles), the probability estimate will be less accurate due to a smaller amount of shared genetic material among distant relatives. However, with genetic testing of distant relatives, probability estimates can become more accurate with a greater number of tested individuals. Generally, genetic testing of possible relationships with previous generations (e.g., parents, grandparents) is more reliable than genetic testing with extended relatives in a persons own generation or later generations (e.g., cousins).

Types of Genetic Testing

Paternity and Maternity Testing These tests compare a childs genes to those of a probable parent to confirm or deny their relation. The results are expressed as a probability, a mathematical likelihood of the relation between the possible parent and child. Much of this testing is done through DNA fingerprinting or DNA profiling, which compares specific genetic markers between the two reference samples, known as Variable Number Tandem Repeats (VNTRs), because these markers remain extremely similar from parent to child. This kind of comparative analysis is also used in forensics for building a case against a certain suspect, based on genetic evidence (blood, hair, etc.) left at the scene of the crime. DNA fingerprinting could also be a test for determining likelihood of other extended or immediate familial relations, which might prove useful for those tribes utilizing lineal descent rules for membership and wanting to substantiate them through DNA.

This example from PBS demonstrates how to see similarities in DNA fingerprinting results between family members. Importantly, the PBS example points out that this type of test for paternity can definitively determine who is not the father, and can identify with a slightly less than 100% confidence who is the father. Tribal enrollment officials might find these tests useful to help determine relationships between probable parents and children that are applying for enrollment. If a parent is not available for testing, a grandparent could be tested; however, the certainty of this kind of test is less than that of parental testing because of generational distance. The more distant a familial relationship is, the less certain the DNA fingerprinting results will be.

Genetic Ancestry Testing This kind of testing looks at many genes from an individual and compares their sample to a larger database of research information. This test is based on probabilities and can provide information about how different or similar an individuals DNA is to that of most people within a larger group of people (population). However, these results are limited by the information in current databases, many of which do not contain a lot of information for particular groups (AI/ANs among them). This limitation in the data can produce problems for tribes and individuals seeking information as results may not be accurate or even possible to generate given limited availability of comparative data.

There are many ways to test for genetic ancestry, such as mitochondrial DNA testing (mtDNA), Y-chromosome testing, and analysis of single nucleotide polymorphisms (SNPs). The discussion below explains why these methods are of limited use in tribal enrollment issues.

Mitochondrial DNA (mtDNA):Inside each cell are two structures that contain DNA: the nucleus and hundreds of mitochondria. The mitochondria only come from the mother, as the egg contains the mitochondria that will produce all other mitochondria in the childs cells. The DNA of the mitochondria is identical or extremely similar for the whole of the maternal line. Thus, a genetic test that analyzes mtDNA could provide information about an individual and his/her biological mother as well as other maternal, female relatives in direct lineage, but since this test cannot account for any of the other ancestry of an individual, enrollment officials will only find it of limited use.

Y-Chromosome DNA:Males have a Y-chromosome that comes from their father. The DNA of this chromosome contains sections that remain identical or extremely similar for the whole of the paternal line. A genetic test that analyzes a males Y-chromosomeDNA could thus provide information about that males biological father and direct paternal, male relatives. However, this test is of limited utility for enrollment officials because it is only applicable for males and it does not account for any of the other ancestry of an individual.

Single Nucleotide Polymorphisms (SNPs):DNA is made up of nucleotides, and these building blocks vary between people and groups. Variations in the building blocks are called single nucleotide polymorphisms (SNPs). Specific variations, or SNPs, can be common in a group, but they are also seen in individual genomes. These small changes help to provide an overall profile of an individuals genotype, which is their whole genetic makeup. This kind of genetic test uses statistical probability to estimate how likely it is that an individual comes from a certain region of the world. However, this kind of test cannot conclusively prove that an individual is from a certain tribe. In fact, there are no genetic tests that are specific to a tribe or even American Indian/Alaska Native heritage. Therefore, while individuals may approach tribal enrollment officials with genetic ancestry test results, other records would be of more value and provide more certainty in determining eligibility for enrollment.

One type of genetic testing called Ancestry Informative Markers (AIMs)uses SNPs to examine a persons genetic ancestry. AIMs convey important information about an individuals likely ancestry and differences between populations from different geographic areas. Research in recent years has attempted to link genes with specific ancestry related to geographical locations. For example, Mark Shriver and his lab group have identified genetic variations that are most common in particular populations, and he suggests these can be used to help determine the geographic ancestry of modern people, small groups, and individual persons. Shriver and colleagues write, Ancestry informative markers (AIMs) are genetic loci showing alleles with large frequency differences between populations. AIMs can be used to estimate biogeographical ancestry at the level of the population, subgroup (e.g. cases and controls) and individual (Mark Shriver et al 2003).

As research generates more information, some genetic markers, such as SNPs, appear more commonly in some populations than others. However, these genetic markers do not reflect all of the genetic information in a persons ancestry. With genetic ancestry testing, there are limits to the information available for AI/AN individuals because there are few samples from the AI/AN population in the current databases being used for these tests. Further, these tests do not provide information about all of a persons ancestors. Kim TallBear describes this limitation well in her articles, including an explanation of how a person with AI/AN ancestry may not show up on a genetic test as AI/AN, or may be told they are of East Asian or other descent (TallBear 2003, TallBear and Bolnick 2004). Brett Shelton and Jonathan Marks have also described the limits of DNA testing with respect to Native identity. There is also some concern, highlighted by Marks and Shelton, that both false positives and false negatives occur in these tests. In other words, genetic ancestry testing using AIMs is not totally accurate or precise. With this testing, an individual can be misidentified as AI/AN even if they do not have the genetic markers that are more common among AI/AN peoples. On the other hand, an individual could be misidentified as non-AI/AN even if they do have the genetic markers found more often in AI/AN groups. For this reason, genetic ancestry testing can be viewed as just one piece of a larger puzzle about an individuals ancestry. Other tools should be used to fill in the information throughout the puzzle, or the enrollment application. Kenneth Weiss and Jeffrey Long highlight that not many documented single nucleotide polymorphisms (SNPs) are useful [ancestry informative markers].For example, an AIM intended to reveal Native American ancestry may also be common in East Asians, and not private after all. These authors conclude that Although DNA data have the aura of providing definitive answers to population and individual ancestry questions, they require careful interpretation in terms of both the laws of inheritance and the evolutionary process. Untrained individuals, and even some professionals, will have a difficult time reconciling the nuances of interpretation with the bottom-line aura that DNA carries (Weiss and Long 2009). Thus, scholars have argued that genetic ancestry tests should be interpreted with caution, especially because there is currently not enough data from AI/AN populations to make specific claims to ancestry based on genetic testing.

Considerations Regarding DNA Testing Companies

Tribes that have decided to use DNA testing will face decisions about how to get this testing completed in an ethical and respectful way. Tribes might choose to use genetic testing to provide information about tribal members family relationships or ancestry. This type of genetic testing is usually done by private, commercial genetic testing laboratories. The section below discusses considerations for tribes in working with these private labs. Other sections of this resource guide discuss the collection of genetic information for research, which is different from fee-for-service genetic testing done by private companies. However, because the information encoded in genetic samples and the information attached to those samples (such as family and tribal identities) has potential commercial value, tribes should make certain that samples and identifying information of individuals, their families, and tribes is handled according to tribal preferences. To ensure that tribal preferences in these areas are honored, there should be protective language contained in contracts with DNA testing companies allowed to work with tribal members, as well as clearly defined consequences for failure to observe those contract requirements. Some terms tribes may wish to include in contracts are protections of confidentiality with the samples and predetermined services or monies owed to the tribe if the contract is breached.

Working with Private Labs for Testing In using genetic tests, most tribes will work with private labs for their testing. As with all data collected from tribal citizens, it is important to ensure the protection of the citizens, applicants, and samples submitted to the labs. Written contracts and proper informed consent should be in place to document how specimens and test results will be used. Tribes may wish to work directly with genetic testing labs so that they can ensure the quality of test results provided to individuals who are applying for tribal enrollment, and the security of the information. Moreinformation about lab quality assurance is available on the Genetics Home Resource, particularly under the section How can consumers be sure a genetic test is valid and useful? This resource includes information about certification of labs according to Clinical Laboratory Improvement Amendments. Testing centers may also provide information on their own websites about choosing a lab. For additional considerations in choosing a lab, please see this summary handout.

Direct to Consumer (DTC) Testing Many companies will perform testing of a persons DNA profile or genetic ancestry for a fee. The information that these companies provide has a limit to accuracy (in how much of ones ancestry it can reflect). It also needs to be interpreted by professionals, such as doctors for health information, or scientists who can understand the implications and limitations of information about genetic ancestry. Claims by genetic testing companies should be evaluated by the consumer for accuracy. Tribal officials, tribal members, and potential members would benefit from carefully examining any companys claims before getting testing or using that testing for enrollment. For example, the American Society for Human Genetics issued a statement about ancestry testing companies in 2008. Knowing which company provides what information, and what that information can and cannot do for a consumer (whether tribe or individual), is important.

Issues and Considerations in Using DNA Testing for Tribal Enrollment

Recent advances in DNA testing have brought with them possibilities for using DNA testing as criteria for tribal enrollment. Many people have found the prospect that these DNA tests can provide a concrete yes or no answer about biological relationships (parentage and descent) to be an attractive and positive aspect of using these tests. However, using DNA testing may limit the understanding of tribal identity to only a biological understanding if it is not supplemented with other tools or methods of determining tribal identity (or enrollment eligibility). Further, there are concerns that DNA testing within families and communities could reveal information about parents and lineage that contradicts other claims or family stories. More specifically each kind of testing offers particular positive aspects and some challenges above and beyond these basics.

Parental Testing This kind of testing determines the parentage of a given child.Positive Aspects: Can prove biological parentage. Confirms or denies the biological connection between two sampled individuals.Challenges:Restricts definition of family to biological relationships, versus a more expansive understanding of kinship.

DNA Fingerprinting This kind of testing looks at larger relationships in a family or community, not only direct parental lineage.Positive Aspects: Can prove larger family connections, including parentage and some other types of relatedness.Confirms or denies the biological connection between two sampled individuals.Challenges: Could reveal information about familial connections previously unknown or contradict family histories.Ignores and potentially contradicts some tribal concepts of family that are not biologically based.

Genetic Ancestry Testing This kind of testing looks at more historical connections; however, it cannot reflect the whole of a persons ancestry but instead traces ancestry through specific variations in genes.Positive Aspects: Mitochondrial DNA testing proves maternal connections, and can prove clan as traced through the mother. Y-chromosome testing proves paternal connection, and can prove clan as traced through the father for a son.AIMs can be very specific to a geographical area, and their use may enable tribes to organize in new ways.Confirms or denies biological connection to a population or historical sample.Challenges: Mitochondrial DNA testing restricts information to maternity of a particular child, and to the female line of descent.Y-chromosome testing restricts information to the father-son relationship, and to the male line of descent.Biologically determined but not definitely culturally specific. Only as accurate as the comparison samples and research in a database (for AIM testing). Could produce evidence that undermines homeland or historical descent claims.Ignores and potentially contradicts other tribal conceptualization of relationships.Can be used to undermine tribal ancestral stories.

The use of DNA testing for tribal enrollment raises many issues. Tribal enrollment criteria each represent a different value or set of values that the community holds. Over time, as the community changes so too might the membership criteria or the value that they represent. For example, lineal descendancy demonstrates a value of proven biological relation to a particular historical census record of tribal members. DNA testing may provide another tool to uphold such a value, but it has limits and is not the only tool that may be useful. When considering tribal membership requirements and whether DNA testing should become one, tribal leaders and community members might consider the values of the current criteria, the added (or not) value of DNA testing, the potential challenges associated with using a particular kind of DNA test, and particularly how it compares to other DNA testing. While genetic tests cannot determine whether an individual is AI/AN or not, they can determine whether people are likely related to one another. This limitation means that genetic testing will not be helpful in many enrollment cases, but it can be helpful for some areas with less documentation of family relationships or the need to confirm direct biological relationships.

Case Studies: How Tribes Are Currently Using DNA Testing

Case Study A: Using DNA testing to inform new tribal enrollment decisions

The Mashpee Wampanoag and the Eastern Band of Cherokee Indians have used DNA testing to prove or disprove both maternity and paternity claims by potential tribal enrollees. While the Mashpee have been using the testing for a decade as one piece of information obtained in their application for enrollment, the EBCI turned to this method of corroborating birth records and supporting applications for tribal enrollment after an audit of the rolls by the Falmouth Institute indicated that many documents, such as birth certificates, were missing from files of enrolled citizens.

The audit report from the Falmouth Institute is provided for information about the status of the EBCIs enrollment records immediately prior to the change in criteria. Also, links to newspaper articles about how community members reacted to the use of DNA are included below for additional information.

Morris and Giles Cherokee Enrollment Quandary leads to talk of DNA testing

Morris and Giles, Tribe moves to implement DNA for new applicants to Cherokee rolls

These two tribal enrollment ordinances and the newspaper reporting on one of them may help in considering the following questions:

Case Study B: DNA Testing for Disenrollment: DNA testing has been used not only as a criterion for tribal enrollment, but also for disenrollment. When DNA testing is used on the current citizenry, the testing may contradict family relationships described in original enrollment applications. However, this discrepancy may not even be known by the citizen in question because they may have been raised to believe certain information about their parentage and family. For example, in an article published in Indian Country Today, Kevin Taylor presents the stories of individuals disenrolled from tribal citizenship as a result of DNA testing. He also discusses how other individuals are using DNA testing to make a case for their enrollment applications to tribal nations. The article demonstrates that there are still many complications within a choice to use DNA testing for any aspect of tribal enrollment, and not all groups will agree on how or if they want to use this technology. Taylors article may help in considering the following questions:

Case Study C: Federal Recognition of Tribes: In 2000, legislation was introduced in the Vermont legislature in an attempt to secure federal recognition for the Western Mohegan tribe after they paid for DNA testing[2] to prove their genetic similarity to a federally recognized tribe in Wisconsin. The Western Mohegan tribe used these genetic test results to argue for the historical existence of their tribe as part of their application for federal recognition. These efforts indicate a hope for DNA to do what has previously been unsuccessful by certain tribal groups: to prove their community identity. However, the wording of the legislation would have caused other Vermont tribes to require DNA testing, and the legislator who introduced the bill spoke of American Indians as a biologically and racially determined group instead of sovereign nations. Kim TallBears article (2003, pg. 85-86) describes these events in more detail. TallBears article helps in considering the following questions:

In sum, identity is a sensitive issue for many American Indian peoples and nations. The ability to determine the political and legal identity of citizens/members remains within the realm of tribal sovereignty. How enrollment is determined through certain criteria is specific to each and every tribal nation. These differences mean that while DNA testing may be useful for some tribes, it may not be useful to others. Further, what works now may not be the same as what is needed or wanted in future generations, just as past generations adapted enrollment practices over time with different technologies, methods, and documents. The sections above have reviewed the use of DNA testing as a potential tribal enrollment criterion. The questions offered are intended to help tribal leaders and community members consider how DNA testing might be used in their own community contexts, should they decide to do so.

[1]In some cases, a genetic test can conclusively say that if an individual has a specific gene(s) , they will develop a disease (e.g., Huntingtons Disease). Other genetic tests can indicate if an individual is more likely to develop a chronic disease (e.g., diabetes or heart disease).

[2] Specifically, this tribe used a form of DNA testing not previously discussed that looks at genes of the immune system and compares these between individuals. This type of testing is most commonly used for organ transplantation. The tests discussed in this paper, and more often available and marketed to tribes, are more comprehensive types of DNA testing.

Photo Credit:NativeStock PicturesUsed with permission. All rights reserved.

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Current Strategies and Challenges for Purification of …

Theranostics 2017; 7(7):2067-2077. doi:10.7150/thno.19427

Review

Kiwon Ban1, Seongho Bae2, Young-sup Yoon2, 3

1. Department of Biomedical Sciences, City University of Hong Kong, Hong Kong;2. Department of Medicine, Division of Cardiology, Emory University, Atlanta, Georgia, USA;3. Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea.

This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY-NC) license (https://creativecommons.org/licenses/by-nc/4.0/). See http://ivyspring.com/terms for full terms and conditions.

Cardiomyocytes (CMs) derived from human pluripotent stem cells (hPSCs) are considered a most promising option for cell-based cardiac repair. Hence, various protocols have been developed for differentiating hPSCs into CMs. Despite remarkable improvement in the generation of hPSC-CMs, without purification, these protocols can only generate mixed cell populations including undifferentiated hPSCs or non-CMs, which may elicit adverse outcomes. Therefore, one of the major challenges for clinical use of hPSC-CMs is the development of efficient isolation techniques that allow enrichment of hPSC-CMs. In this review, we will discuss diverse strategies that have been developed to enrich hPSC-CMs. We will describe major characteristics of individual hPSC-CM purification methods including their scientific principles, advantages, limitations, and needed improvements. Development of a comprehensive system which can enrich hPSC-CMs will be ultimately useful for cell therapy for diseased hearts, human cardiac disease modeling, cardiac toxicity screening, and cardiac tissue engineering.

Keywords: Cardiomyocytes, hPSCs

Heart failure is the leading cause of death worldwide [1]. Approximately 6 million people suffer from heart failure in the United States every year [1]. Despite this high incidence, existing surgical and pharmacological interventions for treating heart failure are limited because these approaches only delay the progression of the disease; they cannot directly repair the damaged hearts [2]. In the case of large myocardial infarction (MI), patients progress to heart failure and die within short time from the onset of symptoms [3].

The adult human heart has minimal regenerative capacity, because during mammalian development, the proliferative capacity of cardiomyocytes (CMs) progressively diminishes and becomes terminally differentiated shortly after birth [4].Therefore, once CMs are damaged, they are rarely restored [5]. When MI occurs, the infarcted area is easily converted to non-contractile scar tissue due to loss of CMs and replacement by fibrosis [6]. Development of a fibroblastic scar initiates a series of events that lead to adverse remodeling, hypertrophy, and eventual heart failure [2, 3, 7].

While heart transplantation is considered the most viable option for treating advanced heart failure, the number of available donor hearts is always less than needed [6]. Therefore, more realistic therapeutic options have been required [2]. Accordingly, over the past two decades, cell-based cardiac repair has been intensively pursued [2, 7]. Several different cell types have been tested and varied outcomes were obtained. Indeed, the key factor for successful cell-based cardiac repair is to find the optimal cell type that can restore normal heart function. Naturally, CMs have been considered the best cell type to repair a damaged heart [8]. In fact, many scientists hypothesized that implanted CMs would survive in damaged hearts and form junctions with host CMs and synchronously contract with the host myocardium [9]. In fact, animal studies with primary fetal or neonatal CMs demonstrated that transplanted CMs could survive in infarcted hearts [9-11]. These primary CMs reduced scar size, increased wall thickness, and improved cardiac contractile function with signs of electro-mechanical integration [9-11]. These studies strongly suggest that CMs can be a promising source to repair the heart. However, the short supply and ethical concerns disallow using primary human CMs. In a patient with ischemic cardiomyopathy, about 40-50% of the CMs are lost in 40 to 60 grams of heart tissue [7]. Even if we seek to regenerate a fairly small portion of the damaged myocardium, a large number of human primary CMs would be required, which is impossible.

Accordingly, CMs differentiated from human pluripotent stem cells (hPSCs) including both embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) have emerged as a promising option for candidate CMs for cell therapy [12, 13]. hPSCs have many advantages as a source for CMs. First, hPSCs have obvious cardiomyogenic potential. hPSC derived-CMs (hPSC-CMs) possess a clear cardiac phenotype, displaying spontaneous contraction, cardiac excitation-contraction (EC) coupling, and expression of cardiac transcription factors, cardiac ion channels, and cardiac structural proteins [14, 15]. Second, undifferentiated hPSCs and their differentiated cardiac progeny display significant proliferation capacity, allowing generation of a large number of hPSC-CMs. Lastly, many pre-clinical studies demonstrated that implantation of hPSC-CMs can repair injured hearts and improve cardiac function [16-19]. Histologically, implanted hPSC-CMs are engrafted, aligned and coupled with the host CMs in a synchronized manner [16-19].

In the last two decades, various protocols for differentiating hPSCs into CMs have been developed to improve the efficiency, purity and clinical compatibility [20] [18]. The reported differentiation methods include, but are not limited to: differentiation via embryoid body (EB) formation [20], co-culture with END-2 cells [18], and monolayer culture [15, 21, 22]. The EB-mediated CM differentiation protocol is one of the most widely employed methods due to its simple procedure and low cost. However, it often becomes labor-intensive to produce scalable EBs for further differentiation, which makes it difficult for therapeutic applications. EB-mediated differentiation also produces inconsistent results, showing beating CMs from 5% to 70% of EBs. Recently, researchers developed monolayer methods to complement the problems of EB-based methods [15, 21, 22]. In one representative protocol, hPSCs are cultured at a high density (up to 80%) and treated with a high concentration of Activin A (100 ng/ml) for 1 day and BMP4 (10 ng/ml) for 4 days followed by continuous culture on regular RPMI media with B27 [15]. This protocol induces spontaneous beating at approximately 12 days and produces approximately 40% CMs after 3 weeks. These hPSC-CMs can be further cultured in RPMI-B27 medium for another 2-3 weeks without significant cell damage [15]. However, these protocols use media with proprietary formulations, which complicates clinical application. As shown, most monolayer-based methods employ B27, which is a complex mix of 21 components. Some of the components of B27, including bovine serum albumin (BSA), are animal-derived products, and the effects of B27 components on differentiation, maturation or subtype specification processes are poorly defined. In 2014, Burridge and his colleagues developed an advanced protocol that is defined, cost-effective and efficient [22]. By subtracting one component from B27 at a time and proceeding with cardiac differentiation, the researchers reported that BSA and L-ascorbic acid 2-phosphate are essential components in cardiac differentiation. Subsequently, by replacing BSA with rice-derived recombinant human albumin, the chemically defined medium with 3 components (CDM3) was produced. The application of a GSK-inhibitor, CHIR99021, for the first 2 days followed by 2 days of the Wnt-inhibitor Wnt-59 to cells is an optimal culture condition in CDM3 resulting in similar levels of live-cell yields and CM differentiation [22].

Despite remarkable improvement in the generation of hPSC-CMs, obtaining pure populations of hPSC-CMs still remains challenging. Currently available methods can only generate a mixture of cells which include not only CMs but other cell types. This is one of the most critical barriers for applications of hPSC-CMs in regenerative therapy, drug discovery, and disease investigation. For Instance, cardiac transplantation of non-pure hPSC-CMs mixed with undifferentiated hPSCs or other cell types may produce tumors or unwanted cell types in hearts [23-28]. Accordingly, a pure or enriched population of hPSC-CMs would be required, particularly for cardiac cell therapy. Enriched hPSC-CMs would also be more beneficial for myocardial repair due to improved electric and mechanical properties [29]. A pure, homogeneous population of hPSC-CMs would pose less arrhythmic risk and have enhanced contractile performance, and would be more useful in disease modeling as they better reflect native CM physiology. Finally, purified hPSC-CMs would better serve for testing drug efficacy and toxicity. Therefore, many researchers have tried to develop methods to purify CMs from cardiomyogenically differentiated hPSCs.

There are three important topics that are not addressed in this review. First is the beneficial role of other cell types such as endothelial cells and fibroblasts in the integration, survival, and function of CMs [30-32]. We did not discuss this issue because it would need a separate review due to the volume of material. While the roles of such cells are important, the value of having purified hPSC-CMs is not diminished. Although cell mixtures or tissue engineered products can be used, unless purified CMs are employed, they would form tumors or other cells/tissues when implanted in vivo. Our point here is that even if cardiomyocytes are mixed with non-CMs, all cells should be clearly defined and purified as well. If the mixture is made in a non-purified or non-defined manner (for example, an unsophisticated top-down approach), there would be undefined cells that are neither CMs, ECs, nor fibroblasts and these unidentified cells will make aberrant tissues or tumors. Second, we did not deal with maturation of hPSC-CMs because of its broad scope and depth [33, 34]. Third is direct reprogramming or conversion of somatic cells into CMs. There has been another advancement in the generation of CMs by directly reprogramming or converting somatic cells into CM-like cells by introducing a combination of cardiac transcription factors (TFs) or muscle-specific microRNAs (miRNAs) both in vitro and in vivo [35-41]. These cells are referred to as induced CMs (iCMs) or cardiac-like myocytes (iCLMs). While this is an important advancement, we did not cover this topic either due to its size. Accordingly, this review will focus on the various strategies for purifying or enriching hPSC-CMs reported to date (Figure 1).

Early on, researchers isolated hPSC-CMs manually under microscopy by mechanically separating out the beating areas from myogenically differentiating hPSC cultures [18, 20, 42]. This method usually generates 5-70% hPSC-CMs. Although generally crude, it can enrich even higher percentages of CMs with further culture. This manual isolation method has the advantage of being easy, but while it can be useful for small-scale research, it is very labor intensive and not scalable, precluding large scale research or clinical application.

Currently available strategies for enriching cardiomyocytes derived from human pluripotent stem cells.

Xu et el. reported that hPSC-CMs, due to their physical and structural properties, can be enriched by Percoll density gradient centrifugation [43]. Percoll was first formulated by Pertoft et al [44] and it was originally developed for the isolation of cells, organelles, or viruses by density centrifugation. The Percoll-based method has several advantages. The procedure for Percoll-based separation is very simple and easy, it is inexpensive, and its low viscosity allows more rapid sedimentation and lower centrifugal forces compared to a sucrose density gradient. Lastly, it can be prepared and kept for a long time in an isotonic solution to maintain osmolarity. Although Percoll separation has resulted in major improvements in hPSC-CM isolation procedures, it has clear limitations with regard to purity and scalability. Previous studies found that Percoll separation is only able to enrich 40 -70% of hPSC-CMs. It is also not compatible with large-scale enrichment of hPSC-CMs.

Another traditional method for purifying hPSC-CMs is based on the expression of a drug resistant gene or a fluorescent reporter gene such as eGFP or DsRed, which is driven by a cardiac specific promoter in genetically modified hPSC lines [45, 46]. Here, enrichment of hPSC-CMs can be achieved by either drug treatment to eliminate cells that do not express the drug resistant gene or with FACS to isolate fluorescent cells [47, 48].

Briefly, enrichment of PSC-CMs by genetically based selection was first reported by Klug et al [49]. The authors generated murine ES cell lines via permanent gene transfection of the aminoglycoside phosphotransferase gene driven by the MHC (MYH7) promoter. With this approach, highly purified murine ESC-CMs up to 99% were achieved. Next, several studies reported the use of various CM-specific promoters to enrich ESC-CMs such as Mhc (Myh6), Myh7, Ncx (Sodium Calcium exchanger) and Mlc2v (Myl2) [46, 50, 51]. In the case of hESCs, MHC/EGFP hESCs were generated by permanent transfection of the EGFP-tagged MHC promoter [52]. Similarly, an NKX2.5/eGFP hESC line was generated to enrich GFP positive CMs [53]. However, since MHC and NKX2.5 are expressed in general CMs, the resulting CMs contain a mixture of the three subtypes of CMs, nodal-, atrial-, and ventricular-like CMs. To enrich only ventricular-like CMs, Huber et al. generated MLC2v/GFP ESCs to be able to isolate MLC2v/GFP positive ventricular-like cells by FACS [52] [54-57]. In addition, the cGATA6 gene was used to purify nodal-like hESC-CMs [58]. Future studies should focus on testing new types of cardiac specific promoters and devising advanced selection procedures to improve this strategy.

While fluorescence-based cell sorting is more widely used, the drug selection method may be a better approach to enrich high purity of hPSC-CMs during differentiation/culture as it does not require FACS. The advantage is its capability for high-purity cell enrichment due to specific gene-based cell sorting. These highly pure cells can allow more precise mechanistic studies and disease modeling. Despite its many advantages, the primary weakness of genetic selection is genetic manipulation, which disallows its use for therapeutic application. Insertion of reporter genes into the host genome requires viral or nonviral transfection/transduction methods, which can induce mutagenesis and tumor formation [50, 59-61].

Practically, antibody-based cell enrichment is the best method for cell purification to date. When cell type-specific surface proteins or marker proteins are known, one can tag cells with antibodies against the proteins and sort the target cells by FACS or magnetic-activated cell sorting (MACS). The main advantage is its specificity and sensitivity, and its utility is well demonstrated in research and even in clinical therapy with hematopoietic cells [62]. Another advantage is that multiple surface markers can be used at the same time to isolate target cells when one marker is not sufficient. However, no studies have reported surface markers that are specific for CMs, even after many years. Recently, though, several researchers demonstrated that certain proteins can be useful for isolating hPSC-CMs.

In earlier studies, KDR (FLK1 or VEGFR2) and PDGFR- were used to isolate cardiac progenitor cells [63]. However, since these markers are also expressed on hematopoietic cells, endothelial cells, and smooth muscle cells, they could not enrich only hPSC-CMs. Next, two independent studies reported two surface proteins, SIRPA [64] and VCAM-1 [65], which it was claimed could specifically identify hPSC-CMs. Dubois et al. screened a panel of 370 known antibodies against CMs differentiated from hESCs and identified SIRPA as a specific surface protein expressed on hPSC-CMs [64]. FACS with anti-SIRPA antibody enabled the purification of CMs and cardiac precursors from cardiomyogenically differentiating hPSC cultures, producing cardiac troponin T (TNNT2, also known as cTNT)-positive cells, which are generally considered hPSC-CMs, with up to 98% purity. In addition, a study performed by Elliot and colleagues identified another cell surface marker, VCAM1 [53]. In this study, the authors used NKX2.5/eGFP hESCs to generate hPSC-CMs, allowing the cells to be sorted by their NKX2.5 expression. NKX2.5 is a well-known cardiac transcription factor and a specific marker for cardiac progenitor cells [66, 67]. To identify CM-specific surface proteins, the authors performed expression profiling analyses and found that expression levels of both VCAM1 and SIRPA were significantly upregulated in NKX2.5/eGFP+ cells. Flow cytometry results showed that both proteins were expressed on the cell surface of NKX2.5/eGFP+ cells. Differentiation day 14 NKX2.5/eGFP+ cells expressed VCAM1 (71 %) or SIRPA (85%) or both VCAM1 and SIRPA (37%). When the FACS-sorted SIRPA-VCAM1-, SIRPA+ or SIRPA+VCAM1+ cells were further cultured, only SIRPA+ or SIRPA+VCAM1+ cells showed NKX2.5/eGFP+ contracting portion. Of note, NKX2.5/eGFP and SIRPA positive cells showed higher expression of smooth muscle cell and endothelial cell markers indicating that cells sorted solely based on SIRPA expression may not be of pure cardiac lineage. Hence, the authors concluded that a more purified population of hPSC-CMs could be isolated by sorting with both cell surface markers. Despite significant improvements, it appears that these surface markers are not exclusively specific for CMs as these antibodies also mark other cell types including smooth muscle cells and endothelial cells. Furthermore, they are also known to be expressed in the brain and the lung, which raises concerns whether these surface proteins can be used as sole markers for the purification of hPSC-CMs compatible for clinical applications.

More recently, Protze et al. reported successful differentiation and enrichment of sinoatrial node-like pacemaker cells (SANLPCs) from differentiating hPSCs by using cell surface markers and an NKX2-5-reporter hPSC line [68]. They found that BMP signaling specified cardiac mesoderm toward the SANLPC fate and retinoic acid signaling enhanced the pacemaker phenotype. Furthermore, they showed that later inhibition of the FGF pathway, the TFG pathway, and the WNT pathway shifted cell fate into SANLPCs, and final cell sorting for SIRPA-positive and CD90-negative cells resulted in enrichment of SANLPCs up to ~83%. These SIRPA+CD90- cells showed the molecular, cellular and electrophysiological characteristics of SANLPCs [68]. While this study makes important progress in enriching SANLPCs by modulating signaling pathways, no specific surface markers for SANLPCs were identified and the yield was still short of what is usually expected for cells purified via FACS.

Hattori et al. developed a highly efficient non-genetic method for purifying hPSC-derived CMs, in which they employed a red fluorescent dye, tetramethylrhodamine methyl ester perchlorate (TMRM), that can label active mitochondria. Since CMs contain a large number of mitochondria, CMs from mice and marmosets (monkey) could be strongly stained with TMRM [69]. They further found that primary CMs from several different types of animals and CMs derived from both mESCs and hESCs were successfully purified by FACS up to 99% based on the TMRM signals. In addition to its efficiency for CM enrichment, TMRM did not affect cell viability and disappeared completely from the cells within 24 hrs. Importantly, injected hPSC-CMs purified in this way did not form teratoma in the heart tissues. However, since TMRM only functions in CMs with high mitochondrial density, this method cannot purify entire populations of hPSC-CMs [64]. While originally TMRM was claimed to be able to isolate mature hPSC-CMs, mounting evidence indicates that hPSC-CMs are similar to immature human CMs at embryonic or fetal stages. Therefore, both the exact phenotype of the cells isolated by TMRM and its utility are rather questionable [33, 34]. Two subsequent studies demonstrated that TMRM failed to accurately distinguish hPSC-CMs due to the insufficient amounts of mitochondria [64].

Employing the unique metabolic properties of CMs, Tohyama et al. developed an elegant purification method to enrich PSC-CMs [70]. This approach is based on the remarkable biochemical differences in lactate and glucose metabolism between CMs and non-CMs, including undifferentiated cells. Mammalian cells use glucose as their main energy source [71]. However, CMs are capable of energy production from different sources such as lactate or fatty acids [71]. A comparative transcriptome analysis was performed to detect metabolism-related genes which have different expression patterns between newborn mouse CMs and undifferentiated mouse ESCs. These results showed that CMs expressed genes encoding tricarboxylic acid (TCA) cycle enzymes more than genes related to lipid and amino acid synthesis and the pentose phosphate cycle compared to undifferentiated ESCs. To further prove this observation, they compared the metabolites of these pathways using fluxome analysis between CMs and other cell types such as ESCs, hepatocytes and skeletal muscle cells, and found that CMs have lower levels of metabolites related to lipid and amino acid synthesis and pentose phosphate. Subsequently, authors cultured newborn rat CMs and mouse ESCs in media with lactate, forcing the cells to use the TCA cycle instead of glucose, and they observed that CMs were the only cells to survive this condition for even 96 hrs. They further found that when PSC derivatives were cultured in lactate-supplemented and glucose-depleted culture medium, only CMs survived. Their yield of CM population was up to 99% and no tumors were formed when these CMs were transplanted into hearts. This lactate-based method has many advantages: its simple procedures, ease of application, no use of FACS for cell sorting, and relatively low cost. More recently, this method was applied to large-scale CM aggregates to ensure scalability. As a follow-up study, the same group recently reported a more refined lactate-based enrichment method which further depletes glutamine in addition to glucose [72]. The authors found that glutamine is essential for the survival of hPSCs since hPSCs are highly dependent on glycolysis for energy production rather than oxidative phosphorylation. The use of glutamine- and glucose-depleted lactate-containing media resulted in more highly purified hPSC-CMs with less than 0.001% of residual PSCs [72]. One concern of this lactate-based enrichment method is the health of the purified hPSC-CMs, because physiological and functional characteristics of hPSC-CMs cultured in glucose- and glutamine-depleted media for a long time may have functional impairment since CMs with mature mitochondria were not able to survive without glucose and glutamine, although they were able to use lactate to synthesize pyruvate and glutamate [72]. In addition, this lactate-based strategy can only be applied to hPSC- CMs, but not other hPSC derived cells such as neuron or -cells.

Our group also recently reported a new method to isolate hPSC-CMs by directly labelling cardiac specific mRNAs using nano-sized probes called molecular beacons (MBs) [29, 73, 74]. Designed to detect intracellular mRNA targets, MBs are dual-labeled antisense oligonucleotide (ODN) nano-scale probes with a DNA or RNA backbone, a Cy3 fluorophore at the 5' end, and a Black Hole quencher 2 (BHQ2) at the 3' end [75, 76]. They form a stem-loop (hairpin) structure in the absence of a complementary target, quenching the fluorescence of the reporter. Hybridization with the target mRNA opens the hairpin and physically separates the reporter from the quencher, allowing a fluorescence signal to be emitted upon excitation. The MB-based method can be applied to the purification of any cell type that has known specific gene(s) [77].

In one study [29], we designed five MBs targeting unique sites in TNNT2 or MYH6/7 mRNA in both mouse and human. To determine the most efficient transfection method to deliver MBs into living cells, various methods were tested and nucleofection was found to have the highest efficiency. Next, we tested the sensitivity and specificity of MBs using an immortalized mouse CM cell line, HL-1, and other cell types. Finally, we narrowed it down to one MB, MHC-MB, which showed >98% sensitivity and > 95% specificity. This MHC-MB was applied to cardiomyogenically differentiated mouse and human PSCs and FACS sorting was performed. The resultant MHC-MB-positive cells expressed cardiac proteins at ~97% when measured by flow cytometry. These sorted cells also demonstrated spontaneous contraction and all the molecular and electrophysiological signatures of human CMs. Importantly, when these purified CMs were injected into the mouse infarcted myocardium, they were well integrated into the myocardium without forming any tumors, and they improved cardiac function.

In a subsequent study [74], we refined a method to enrich ventricular CMs from differentiating PSCs (vCMs) by targeting a transcription factor which is not robustly expressed in cells. Since vCMs are the main source for generating cardiac contractile forces and the most frequently damaged in the heart, there has been great demand to develop a method that can obtain a pure population of vCMs for cardiac repair. Despite this critical unmet need, no studies have demonstrated the feasibility of isolating ventricular CMs without permanently altering their genome. Accordingly, we first designed MBs targeting the Iroquois homeobox protein 4 (Irx4) mRNA, a vCM specific transcription factor [78, 79]. After testing sensitivity and specificity, one IRX4-MB was selected and applied to myogenically differentiated mPSCs. The FACS-sorted IRX4-MB-positive cells exhibited vCM-like action potentials in more than 98% of cells when measured by several electrophysiological analyses including patch clamp and Ca2+ transient analyses. Furthermore, these cells maintained spontaneous contraction and expression of vCM-specific proteins.

The MB-based cell purification method is theoretically the most broadly applicable technology among the purification methods because it can isolate any target cells expressing any specific gene. Thus, the MB-based sorting technique can be applied to the isolation of other cell types such as neural-lineage cells or islet cells, which are critical elements in regenerative medicine but do not have specific surface proteins identified to date. In addition, theoretically, this technology may have the highest efficiency when MBs are designed to have the maximum sensitivity and specificity for the cells of interest, but not others. These characteristics are particularly important for cell therapy. Despite these advantages, the delivery method of MB into the cells needs to be improved. So far, nucleofection is the best delivery method, but caused some cell damage with

Recently, Miki and colleagues reported a novel method for purifying cells of interest based on endogenous miRNA activity [80]. Miki et al. employed several synthetic mRNA switches (= miRNA switch), which consist of synthetic mRNA sequences that include a recognition sequence for miRNA and an open reading frame that codes a desired gene, such as a regulatory protein that emits fluorescence or promotes cell death. If the miRNA recognition sequence binds to miRNA expressed in the desired cells, the expression of the regulatory protein is suppressed, thus distinguishing the cell type from others that do not contain the miRNA and express the protein.

Briefly, the authors first identified 109 miRNA candidates differentially expressed in distinct stages of hPSC-CMs (differentiation day 8 and 20). Next, they found that 14 miRNAs were co-expressed in hPSC-CMs at day 8 and day 20 and generated synthetic mRNAs that recognize these 14 miRNA, called miRNA switches. Among those miRNA switches, miR-1-, miR-208a-, and miR-499a-5p-switches successfully enriched hPSC-CMs with purity of sorted cells up to 96% determined by TNNT2 intracellular flow cytometry. Particularly, hPSC-CMs enriched by the miR-1-switch showed substantially higher expression of several cardiac specific genes/proteins and lower expression of non-CM genes/proteins compared with control cells. Patch clamp confirmed that these purified hPSC-CMs possessed both ventricular-like and atrial-like action potentials.

One of the major advantages of this technology is its wider applicability to other cell types. miRNA switches have the flexibility to design the open reading frame in the mRNA sequence such that any desired transgene can be incorporated into the miRNA switches to regulate the cell phenotype based on miRNA activity. The authors tested this possibility by incorporating BIM sequence, an apoptosis inducer, into the cardiac specific miR-1- and miR-208a switches and tested whether they could selectively induce apoptosis in non-CMs. They found that miR-1- and miR-208a-Bim-switches successfully enriched cTNT-positive hPSC-CMs without cell sorting. Enriched hPSC-CMs by 208a-Bim-switch were injected into the hearts of mice with acute MI and they engrafted, survived, expressed both cTNT and CX43, and formed gap junctions with the host myocardium. No teratoma was detected. In addition, other miRNA switches such as miR-126-, miR-122-5p-, and miR-375-switches targeting endothelial cells, hepatocytes, and -cells, respectively, successfully enriched these cell types differentiated from hPSCs. However, identification of specific miRNAs expressed only in the specific cell type of interest and verification of their specificity in target cells will be key issues for continuing to use this miRNA-based cell enrichment method.

Recent advances in biomedical engineering have contributed to developing systems that can isolate target cells using physicochemical properties of the cells. Microfluidic systems have been intensively applied for cell separation due to recent improvements in miniaturizing a cell culture system [81-83]. These advances made possible the design of automated microfluidic devices with cellular microenvironments and controlled fluid flows that save time and cost in experiments. Thus, there have been an increasing number of studies seeking to apply the microfluidic system for cell separation. Among the first, Singh et al. tested the possibility of using a microfluidic system for the separation of hPSC [84] by preparative detachment of hPSCs from differentiating cultures based on differences in the adhesion properties of different cell types. Distinct streams of buffer that generated varying levels of shear stress further allowed selective enrichment of hPSC colonies from mixed populations of adherent non-hPSCs, achieving up to 95% purity. Of note, this strategy produced hPSC survival rates almost two times higher than FACS, reaching 80%.

Subsequently, for hPSC-CMs purification, Xin et al. developed a microfluidic system with integrated ridge-like flow derivations and fishnet-like microcolumns for the enrichment of hiPSC-CMs [85]. This device is composed of a 250 mm-long microfluidic channel, which has two integrated parallel microcolumns with surfaces functionalized with anti-human TRA-1 antibody for undifferentiated hiPSC trapping. Aided by the ridge-like surface patterns on the upper wall of the channel, micro-streams are generated so that the cell suspension of mixed undifferentiated hiPSCs and hiPSC-CMs are forced to cross the functionalized fishnet-like microcolumns, resulting in trapping of undifferentiated hiPSCs due to the interaction between the hiPSCs and the columns, and the untrapped hiPSC-CMs are eventually separated. By modulating flow and coating with anti-human TRA-1 antibody, they were able to enrich CMs to more than 80% purity with 70% viability. While this study demonstrated that a microfluidic device could be used for purifying hPSC-CMs, it was not realistic because the authors used a mixture of only undifferentiated hiPSCs and hiPSC-CMs. In real cardiomyogenically differentiated hiPSCs, undifferentiated hiPSCs are rare and many intermediate stage cells or other cell types are present, so the idea that this simple device can select only hiPSC-CMs from a complex mixture is uncertain.

Overall, the advantages of microfluidic system based cell isolation include fast speed, improved cell viability and low cost owing to the automated microfluidic devices that can control cellular microenvironments and fluid flows [86-88]. However, microfluidic-based cell purification methods have limitations in terms of low purity and scalability [89-92]. In fact, there have been only a few studies demonstrating the feasibility that microfluidic device-based cell separation could achieve higher than 80% purity of target cells. Furthermore, currently available microfluidic devices allow only separation of a small number of cells ( 95% purity.

Having available a large quantity of a homogeneous population of cells of interest is an important factor in advancing biomedical research and clinical medicine, and is especially true for hPSC-CMs. While remarkable progress has been made in the methods for differentiating hPSCs into CMs, technologies to enrich hPSC-CMs, particularly those which are clinically applicable, have been emerging only over the last few years. Contamination with other cell types and even the heterogeneous nature of hPSC-CMs significantly hinder their use for several future applications such as cardiac drug toxicology screening, human cardiac disease modeling, and cell-based cardiac repair. For instance, cardiac drug-screening assays require pure populations of hPSC-CMs, so that the observed signals can be attributed to effects on human CMs. Studies of human cardiac diseases can also be more adequately interpreted with purified populations of patient derived hiPSC-CMs. Clinical applications with hPSC-CMs will need to be free of other PSC derivatives to minimize the risk of teratoma formation and other adverse outcomes.

Summary of representative methods for hPSC-CM purification

Schematic pictures of microfluidic device for enriching hiPSC-CMs. (A) The part of the device designed for trapping undifferentiated hiPSCs. (B) (Left) Illustration of the overall microfluidic device assembled with peristaltic pump, cell suspension reservoirs, and a serpentine channel. (Right) Magnified image showing a channel combining microcolumns and ridge-like flow derivation structures. Modified from Li et al. On chip purification of hiPSC-derived cardiomyocytes using a fishnet-like microstructure. Biofabrication. 2016 Sep 8;8(3): 035017

Therefore, development of reproducible, effective, non-mutagenic, scalable, and economical technologies for purifying hPSC-CMs, independent of hPSC lines or differentiation protocols, is a fundamental requirement for the success of hPSC-CM applications. Fortunately, new technologies based on the biological specificity of CMs such as MITO-tracker, molecular beacons, lactate-enriched-glucose depleted-media, and microRNA switches have been developed. In addition, technologies based on engineering principles have recently yielded a promising platform using microfluidic technology. While due to the short history of this field, more studies are needed to verify the utility of these technologies, the growing attention toward this research is a welcome move.

Another important question raised recently is how to non-genetically purify chamber-specific subtypes of CMs such as ventricular-like, atrial-like and nodal-like hPSC-CMs. So far, only a few studies have addressed this potential with human PSCs. We also showed that a molecular beacon-based strategy could enrich ventricular CMs differentiated from PSCs [74]. Another study demonstrated generation of SA-node like pacemaker cells by using a stepwise treatment of various morphogens and small molecules followed by cell sorting with several sub-specific surface markers. However, the yield of both studies was relatively low (

In summary, technological advances in the purification of hPSC-CMs have opened an avenue for realistic application of hPSC-CMs. Although initial success was achieved for purification of CMs from differentiating hPSC cultures, questions such as scalability, clinical compatibility, and cellular damage remain to be answered and isolation of human subtype CMs has yet to be demonstrated. While there are other challenges such as maturity, in vivo integration, and arrhythmogenecity, this development of purification technology represents major progress in the field and will provide unprecedented opportunities for cell-based therapy, disease modeling, drug discovery, and precision medicine. Furthermore, the availability of chamber-specific CMs with single cell analyses will facilitate more sophisticated investigation of human cardiac development and cardiac pathophysiology.

This work was supported by the Bio & Medical Technology Development Program of the National Research Foundation (NRF) funded by the Korean government (MSIP) (No 2015M3A9C6031514), the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (HI15C2782, HI16C2211) and grants from NHLBI (R01HL127759, R01HL129511), NIDDK (DP3-DK108245). This work was also supported by a CityU Start-up Grant (No 7200492), a CityU Research Project (No 9610355), and a Georgia Immuno Engineering Consortium through funding from Georgia Institute of Technology, Emory University, and the Georgia Research Alliance.

The authors have declared that no competing interest exists.

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56. MLLER M, FLEISCHMANN BK, SELBERT S, JI GJ, ENDL E, MIDDELER G. et al. Selection of ventricular-like cardiomyocytes from ES cells in vitro. FASEB J. 2000;14:2540-8

57. Zhang Q, Jiang J, Han P, Yuan Q, Zhang J, Zhang X. et al. Direct differentiation of atrial and ventricular myocytes from human embryonic stem cells by alternating retinoid signals. Cell Res. 2011;21:579-87

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CRISPR explained: The revolutionary tool that’s transforming …

We are in the midst of a gene-editing revolution.

For four decades, scientists have tinkered with our genes. Since the 1970s, they've experimentally switched them on and off, uncovering their functions; mapped their location within our genome; and even inserted or deleted them in animals, plants and human beings.

And in November 2018, aChinese scientist claimedto have created the world's first genetically modified human beings.

Though scientists have made great inroads into understanding human genetics, editing our genes has remained a complex process requiring imprecise, expensive technology, years of expertise and just a little luck, too.

In 2012, a pair of scientists developed a new tool to modify genes, reshaping the entire field of gene-editing forever: CRISPR. Often described as "a pair of molecular scissors," CRISPR is widely considered the most precise, most cost-effective and quickest way to edit genes. Its potential applications are far-reaching, affecting conservation, agriculture, drug development and how we might fight genetic diseases. It could even alter the entire gene pool of a species.

The field of CRISPR research is still remarkably young, yet we've already seen how it might be used to fight HIV infection, combat invasive species and destroy antibiotic-resistant bacteria. Many unknowns remain, however, including how CRISPR might damage DNA, leading to pathologies such as cancer.

Such a monumental leap in genetic engineering is full of complexities that ask big, often philosophical questions about science, ethics, how we conduct research and the future of humanity itself. With the confirmation that two human embryos were modified using CRISPR and carried to term, those questions have come sharply into focus. The future of gene-editing seemingly arrived overnight.

But what exactly is CRISPR and what are the outstanding concerns about such a powerful tool?

Let's break it all down.

CRISPR has the potential to be used in editing human embryos to create "designer babies."

Few predicted how important CRISPR would become for gene editing upon its discovery 30 years ago.

As early as 1987, researchers at Osaka University studying the function of Escherichia coli genes first noticed a set of short, repeated DNA sequences, but they didn't understand the significance.

Six years later, another microbiologist, Francisco Mojica, noted the sequences in a different single-celled organism, Haloferax mediterranei. The sequences kept appearing in other microbes and in 2002, the unusual DNA structures were given a name: Clustered regularly interspaced short palindromic repeats.

CRISPR.

Studying the sequences more intensely revealed that CRISPR forms an integral part of the "immune system" in bacteria, allowing them to fight off invading viruses. When a virus enters the bacteria, it fights back by cutting up the virus' DNA. This kills the virus and the bacteria stores some of the leftover DNA.

The leftover DNA is like a fingerprint, stored in the CRISPR database. If invaded again, the bacteria produce an enzyme called Cas9 that acts like a fingerprint scanner. Cas9 uses the CRISPR database to match the stored fingerprints with those of the new invader. If it can find a match, Cas9 is able to chop up the invading DNA.

Nature often provides great templates for technological advances. For instance, the nose of a Japanese bullet train is modeled on the kingfisher's beak because the latter is expertly "designed" by evolution to minimize noise as the bird dives into a stream to catch fish.

In a similar way, CRISPR/Cas9's ability to efficiently locate specific genetic sequences, and cut them, inspired a team of scientists to ask whether that ability could be mimicked for other purposes.

The answer would change gene editing forever.

In 2012, pioneering scientists Jennifer Doudna, from UC Berkeley, and Emmanuelle Charpentier, at Umea University Sweden, showed CRISPR could be hijacked and modified. Essentially, they'd turned CRISPR from a bacterial defense mechanism into a DNA-seeking missile strapped to a pair of molecular scissors. Their modified CRISPR system worked marvelously well, finding and cutting any gene they chose.

An illustration of the CRISPR-Cas9 gene editing complex. The Cas9 nuclease protein (white and green) uses a guide RNA (red) sequence to cut DNA (blue) at a complementary site.

Several research groups followed up on the original work, showing that the process was possible in yeast and cultured mouse and human cells.

The floodgates opened, and CRISPR research, which had long been the domain of molecular microbiologists, skyrocketed. The number of articles referencing CRISPR in preeminent research journal Nature has increased by over 6,000 percent between 2012 and 2018.

While other gene-editing tools are still in use, CRISPR provides a gigantic leap because of its precision and reliability. It's really good at finding genes and making accurate cuts. That allows genes to be cut out with ease, but it also provides an opportunity to paste new genes into the gap. Previous gene-editing tools could do this, too, but not with the ease that CRISPR can.

Another huge advantage CRISPR has over alternative gene-editing techniques is its expense. While previous techniques might cost a laboratory upward of $500 to edit a single gene, a CRISPR kit can do the same thing for under $100.

The CRISPR/Cas9 system has been adapted to enable gene editing in organisms including yeast, fungi, rice, tobacco, zebrafish, mice, dogs, rabbits, frogs, monkeys, mosquitoes and, of course, humans -- so its potential applications are enormous.

For research scientists, CRISPR is a tool that provides better, faster tinkering with genes, allowing them to create models of disease in human cell lines and mouse models with much higher proficiency. With better models of say, cancer, researchers are able to fully understand the pathology and how it develops, and that could lead to improved treatment options.

One particular leap in cancer therapy options is the genetic modification of T cells, a type of white blood cell that's critical for the human immune system. A Chinese clinical trial extracted T cells from patients, used CRISPR to delete a gene that usually acts as an immune system brake, and then reintroduced them into the patients in an effort to combat lung cancer. And that's just one of the many trials underway using CRISPR edited cells to fight particular types of cancer.

Beyond cancer, CRISPR has the potential to treat diseases caused by a mutation in a single gene, such as sickle cell anemia or Duchenne muscular dystrophy. Correcting a defective gene is known as gene therapy, and CRISPR is potentially the most powerful way to perform it. Using mouse models, researchers have demonstrated the efficacy of such treatments but human gene therapies using CRISPR remain untested.

Mosquitoes will be targeted using CRISPR gene drives, which could potentially drive malaria-carrying species to extinction.

Then there are CRISPR gene drives, which use CRISPR to guarantee a genetic trait will be passed from parent to offspring -- essentially rewriting the rules of inheritance. Guaranteeing certain genes will spread through a population provides an unprecedented opportunity to tackle mosquito-borne diseases such as malaria, enabling scientists to create infertile mosquitoes in the lab and release them in the wild to crash the population -- or even render a species extinct.

And CRISPR's potential benefits don't end there. The tool opens up new ways of creating antimicrobials to combat rising levels of antibiotic resistance, targeted manipulation of agricultural crops such as wheat to make them hardier or more nutritious, and, potentially, the ability to design human beings, gene by gene.

CRISPR may be the most precise way to cut DNA we've yet discovered, but it's not always perfect.

One of the chief barriers to getting CRISPR effectively working in humans is the risk of "off-target effects." When CRISPR is tasked with hunting down a gene, it sometimes finds genes that look very similar to its target and cuts them, too.

An unintended cut may cause mutations in other genes, leading to pathologies such as cancer, or it may have no effect at all -- but with safety a major concern, scientists will need to ensure CRISPR acts only on the gene it's intended to impact. This work has already begun, and several teams of researchers have tinkered with CRISPR/Cas9 to increase its specificity.

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To date, CRISPR work in humans has been confined to cells that don't pass on their genome to the next generation. But gene editing can also be used to edit embryos and thus, change the human gene pool. In 2015, an expert panel of CRISPR scientists suggested that such editing -- known as germline editing -- would be irresponsible until consensus can be reached on safety, efficacy, regulation and social concerns.

Still, research into germline editing has been occurring for several years. In 2017, scientists in the UK edited human embryos for the first time, and researchers in the US used CRISPR to correct a defective gene that causes heart disease. The ability to edit embryos begins to raise ethical concerns about so-called designer babies, wherein scientists may select beneficial genes to increase physical fitness, intelligence or muscle strength, creeping into the controversial waters of eugenics.

That particular future is likely a long way off -- but the era of editing the human genome has already begun.

On Nov. 25, 2018, Chinese scientist Jiankui He said he had created the world's first CRISPR babies. By using CRISPR, He was able to delete a gene known as CCR5. The modified embryos resulted in the birth of twin girls, known by the pseudonyms Lulu and Nana.

The scientific community widely condemned the research, criticizing He's lack of transparency and asking whether there was an unmet medical need for the two girls to receive such a modification. In the wake of the research, several high-profile researchers involved with CRISPR's creation even suggested a global moratorium on using the tool for germline editing.

Few would argue that He's work highlights a need for stricter regulatory controls and effective oversight of clinical trials in which embryos are edited. While He maintains his own experiment was concerned with improving the health of the twin girls by making them HIV-resistant, the experiment was deemed reckless and ethically wrong and the potential consequences overlooked. In January 2019, the Chinese government said that He acted both unlawfully and unethicallyand would face charges. He was later dismissed by his university.

Jiankui He claimed to have created the world's first gene-edited babies.

The most recent International Summit for Human Genome Editing, in November 2018, concluded, as it did in 2015, "the scientific understanding and technical requirements for clinical practice remain too uncertain and the risks too great to permit clinical trials of germline editing at the time."

He's work, which remains unpublished, heralds the first clinical trial and birth of genetically modified human beings -- which means, whether it was the intention or not, a new era for CRISPR has begun.

We've already seen CRISPR transform the entire field of molecular biology -- and that effect has rippled across the biological and medical fields at lightning speed. In only six years, CRISPR went from an evolutionary adaptation in bacteria to a gene-editing tool that, potentially, created the very first genetically modified human beings.

As the revolution surges forward, the greatest challenges will lie in oversight and regulation of the technology, the technical hurdles that science must overcome to ensure it is precise and safe, and the larger societal concerns of tinkering with the stuff that makes us us.

And the Nobel Prize for medicine goes to...: Two researchers for their cancer breakthrough.

Changes in consumer health tech: CES 2018 gets serious about health, wellness and medical tech

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Bone Marrow & Stem Cell Transplant | Weill Cornell Medicine

Bone Marrow & Stem Cell Transplant

The Bone Marrow and Stem Cell Transplant Program at Weill Cornell Medicine was established with the mission of providing the best care and most innovative research in a compassionate and comfortable environment.

We take a multidisciplinary approach to care for patients with cancer and blood diseases who need stem cell transplants, providing world-class clinical care in collaboration with experts in leukemia, lymphoma, myeloma and other blood disorders. Based at NewYork-Presbyterian/Weill Cornell Medical Center, one of the top ten general hospitals in the nation, the expertise of our consulting team is unsurpassed.

Our patients and families cope with life-threatening illness; as such, sensitivity and compassion are a priority for our team. We view each patient as an individual, and our approach ensures that each treatment regimen is narrowly tailored to meet the unique, changing needs of our patients and their families before, during and after transplant.

As New Yorks premier healthcare institution, Weill Cornell Medicine is at the forefront of scientific research and clinical trials, enabling us to provide a full range of diagnostic and treatment protocols, including the latest breakthroughs in medicine.

Our Team

Our team of internationally-recognized bone marrow transplant and stem cell surgery specialists is known for advanced work and published research in:

Treating patients with aggressive leukemia and myelodysplastic syndromes

Bridge protocols for patients with refractory lymphoma and leukemia

Novel strategies to mobilize stem cells and improve transplantation for patients with multiple myeloma, leukemia and lymphoma

Transplants for solid tumors, severe auto-immune disorders, and AIDS

Treatment

We pride ourselves on exceptional outcomes and offer patients the most advanced diagnostic methods and treatment therapies to improve quality of life, including:

Umbilical cord blood transplant

Outpatient transplant

Autologous stem cell transplant; uses stem cells extracted from the bone marrow or peripheral blood of the patients own blood

Allogeneic stem cell transplant; uses stem cells extracted from the bone marrow or peripheral blood of a matching donor

Hematopoietic stem cell transplant; used to treat certain cancers of the blood/bone marrow, including leukemia and myeloma

Matched unrelated donor stem cell transplantation through the National Donor Matching Program

Non-ablative "mini" transplants

Haplo-Cord Transplant, allowing us to find donors for all patients, regardless of age or ethnic background

Bendamustine, a therapy that is well-tolerated and has excellent response rates in patients with myeloma

Novel forms of transplant, offering hope and success to older patients with leukemia

Clinical Trials

Clinical trials are important to improve outcomes and offer new treatment options. At Weill Cornell Medicine, we conduct more studies in blood cancers than any of our regional peers, allowing us to provide our patients with access to many multi-phase clinical trials. As active members of the international cancer research community, our oncologists also collaborate with other research centers to offer patients the most promising treatments available.

Second Opinions

In concert with your referring physician, we are always available to offer a second opinion in the form of a consultation with one of our specialists.

Why Choose Us?

Our collaborative approach means our patients receive supportive, comprehensive care and the most cutting-edge stem cell therapy and treatments. This enables patients to receive the best possible transplant outcomes. Additionally, we offer more allogeneic stem cell transplants for older adults than any other center in New York City and the entire tri-state area.

For more information or to schedule an appointment, call us at 212-746-2119 or 212-746-2646.

Located in New York City, Weill Cornell Medical College is ranked among the nations best by U.S. News & World Report year after year.

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What is BMC, Bone Marrow Stem Cell Therapy?

Bone Marrow Concentrate (BMC) Therapy, also known as Bone Marrow Aspirate Concentrate (BMAC) Therapy, is a promising cutting-edge regenerative therapy to help accelerate healing in moderate to severe osteoarthritis and tendon injuries. While similar to Platelet Rich Plasma (PRP) in its ability to harness the bodys ability to heal itself through the aid of growth factors, BMC also utilizes regenerative cells that are contained within a patients own bone marrow. The marrow contains a rich reservoir of pluripotent stem cells that can be withdrawn from the patients hip bone and used for the procedure. Unlike other cells of the body, stem cells are undifferentiated, meaning they are able to replicate themselves into various types of tissue.

In the past, the process of removing and harvesting these cells was often difficult and expensive. With recent medical advancements in both the aspiration of the bone marrow and harvesting of the regenerative cells, the procedure can be done with minimal discomfort and patients are sent home the same day. The process is relatively simple. The patient is first numbed using a mixture of local anesthetics. Under the guidance of an X-Ray machine, the physician then removes a small amount of the patients bone marrow from the hip bone which is then placed into a centrifuge to separate the regenerative cells and platelets from the rest of the blood products. The final product is a concentrate which has approximately 5-10 times the baseline levels of regenerative cells and growth factors. This point of care treatment allows for minimal manipulation of cells which are then injected to the injured area. The entire process takes approximately 2 hours and patients go home the same day.

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Steroid Replacement Doses for Hypopituitary Patients …

Question: I am completely hypopituitary and had a bilateral adrenalectomy to control my Cushings. I now have Nelsons Syndrome and am on 30mg/day of hydrocortisone replacement. I still have uncontrollable diabetes, muscle weakness and look and feel like I still have Cushings. Is this normal for Nelsons or could my replacement dose be too high?

Answer: Patients who have had a bilateral adrenalectomy for treatment of Cushings disease and are on adequate hydrocortisone replacement should not have any persistent symptoms of Cushings syndrome. Nelson syndrome which occurs when there is an ACTH-secreting pituitary tumor is associated with increased pigmentation of the skin and if the tumor has enlarged, symptoms of tumor growth affecting vision. The problem that may arise on hydrocortisone is that the dose may be excessive for the patients optimal replacement and this hydrocortisone then causes symptoms of Cushings. Patients with hypopituitarism frequently have decreased clearance of cortisol and require a lower dose for maintenance. A good way of determining the right replacement dose of hydrocortisone is to measure urine free cortisol while taking the dose of hydrocortisone in question. Values should be in the middle of the normal reference range. Occasionally patients with hypopituitarism who need hydrocortisone replacement require only small doses of hydrocortisone, from 10 to 15 mg daily.

By Dr. David E. Schteingart MD (Summer, 2005)

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Stem Cell Therapy Has a Lot to OfferIt Just May Take Some …

Stem Cell Therapy Has a Lot to OfferIt Just May Take Some Time to Get There

By: Ashwini Nagappan

In conversation with the New York Times, Dr. Shinya Yamanaka, the director of Kyoto Universitys Center for iPS Cell Research and Application and researcher at the Gladstone Institutes, illuminates the complexities and future of stem-cell research. Yamanaka was jointly awarded the 2012 Nobel Prize in Physiology or Medicine for reconfiguring adult cells back to their pluripotent states. These induced pluripotent stem cells, or iPS cells, have been used as treatments for conditions such as macular degeneration.

However, Yamanaka mentions that these treatments are temporarily suspended because of the possibility of mutations developing in the patients iPS cells. Cancer could be a potential outcome because the production of iPS cells increases the chance of mutations. Researchers are rigorously testing to make sure that there are no cancer-causing mutations and that the cells function as they should. In order to be certain that these cells are safe, they are transplantedinto mice or rats for about a year. Yamanaka approximates that only 100 lines would be needed to cover the Japanese population and 200 lines for the US population.

Yamanaka acknowledges that the potentialfor stem cells may have been too eagerlyanticipated as they can only remedy the small portion of diseases that are caused by a single cell failure such as heart failure. Stem cell therapy cannot target diseases caused by multiple types of cell failures. He mentions an alternative to iPS known as direct cellular reprogramming, which would be beneficial if the patient in question was elderly instead of a younger person, and if the area targeted was larger instead of a small wound.

In essence, Yamanaka highlights the need for an ethical consensus in order to understand how to move forward with advancing stem cell technology. Further, iPS cells are fairly young they are only tenyears old. For patients to be able to receive these treatments requires money and time. In the mean time, Yamanaka recommends arrivingat an ethical consensus onthe use of stem cells.

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Stem Cell Therapy Has a Lot to OfferIt Just May Take Some ...

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heredity | Definition & Facts | Britannica.com

Heredity was for a long time one of the most puzzling and mysterious phenomena of nature. This was so because the sex cells, which form the bridge across which heredity must pass between the generations, are usually invisible to the naked eye. Only after the invention of the microscope early in the 17th century and the subsequent discovery of the sex cells could the essentials of heredity be grasped. Before that time, ancient Greek philosopher and scientist Aristotle (4th century bc) speculated that the relative contributions of the female and the male parents were very unequal; the female was thought to supply what he called the matter and the male the motion. The Institutes of Manu, composed in India between 100 and 300 ad, consider the role of the female like that of the field and of the male like that of the seed; new bodies are formed by the united operation of the seed and the field. In reality both parents transmit the heredity pattern equally, and, on average, children resemble their mothers as much as they do their fathers. Nevertheless, the female and male sex cells may be very different in size and structure; the mass of an egg cell is sometimes millions of times greater than that of a spermatozoon.

The ancient Babylonians knew that pollen from a male date palm tree must be applied to the pistils of a female tree to produce fruit. German botanist Rudolph Jacob Camerarius showed in 1694 that the same is true in corn (maize). Swedish botanist and explorer Carolus Linnaeus in 1760 and German botanist Josef Gottlieb Klreuter, in a series of works published from 1761 to 1798, described crosses of varieties and species of plants. They found that these hybrids were, on the whole, intermediate between the parents, although in some characteristics they might be closer to one parent and in others closer to the other parent. Klreuter compared the offspring of reciprocal crossesi.e., of crosses of variety A functioning as a female to variety B as a male and the reverse, variety B as a female to A as a male. The hybrid progenies of these reciprocal crosses were usually alike, indicating that, contrary to the belief of Aristotle, the hereditary endowment of the progeny was derived equally from the female and the male parents. Many more experiments on plant hybrids were made in the 1800s. These investigations also revealed that hybrids were usually intermediate between the parents. They incidentally recorded most of the facts that later led Gregor Mendel (see below) to formulate his celebrated rules and to found the theory of the gene. Apparently, none of Mendels predecessors saw the significance of the data that were being accumulated. The general intermediacy of hybrids seemed to agree best with the belief that heredity was transmitted from parents to offspring by blood, and this belief was accepted by most 19th-century biologists, including English naturalist Charles Darwin.

The blood theory of heredity, if this notion can be dignified with such a name, is really a part of the folklore antedating scientific biology. It is implicit in such popular phrases as half blood, new blood, and blue blood. It does not mean that heredity is actually transmitted through the red liquid in blood vessels; the essential point is the belief that a parent transmits to each child all its characteristics and that the hereditary endowment of a child is an alloy, a blend of the endowments of its parents, grandparents, and more-remote ancestors. This idea appeals to those who pride themselves on having a noble or remarkable blood line. It strikes a snag, however, when one observes that a child has some characteristics that are not present in either parent but are present in some other relatives or were present in more-remote ancestors. Even more often, one sees that brothers and sisters, though showing a family resemblance in some traits, are clearly different in others. How could the same parents transmit different bloods to each of their children?

Mendel disproved the blood theory. He showed (1) that heredity is transmitted through factors (now called genes) that do not blend but segregate, (2) that parents transmit only one-half of the genes they have to each child, and they transmit different sets of genes to different children, and (3) that, although brothers and sisters receive their heredities from the same parents, they do not receive the same heredities (an exception is identical twins). Mendel thus showed that, even if the eminence of some ancestor were entirely the reflection of his genes, it is quite likely that some of his descendants, especially the more remote ones, would not inherit these good genes at all. In sexually reproducing organisms, humans included, every individual has a unique hereditary endowment.

Lamarckisma school of thought named for the 19th-century pioneer French biologist and evolutionist Jean-Baptiste de Monet, chevalier de Lamarckassumed that characters acquired during an individuals life are inherited by his progeny, or, to put it in modern terms, that the modifications wrought by the environment in the phenotype are reflected in similar changes in the genotype. If this were so, the results of physical exercise would make exercise much easier or even dispensable in a persons offspring. Not only Lamarck but also other 19th-century biologists, including Darwin, accepted the inheritance of acquired traits. It was questioned by German biologist August Weismann, whose famous experiments in the late 1890s on the amputation of tails in generations of mice showed that such modification resulted neither in disappearance nor even in shortening of the tails of the descendants. Weismann concluded that the hereditary endowment of the organism, which he called the germ plasm, is wholly separate and is protected against the influences emanating from the rest of the body, called the somatoplasm, or soma. The germ plasmsomatoplasm are related to the genotypephenotype concepts, but they are not identical and should not be confused with them.

The noninheritance of acquired traits does not mean that the genes cannot be changed by environmental influences; X-rays and other mutagens certainly do change them, and the genotype of a population can be altered by selection. It simply means that what is acquired by parents in their physique and intellect is not inherited by their children. Related to these misconceptions are the beliefs in prepotencyi.e., that some individuals impress their heredities on their progenies more effectively than othersand in prenatal influences or maternal impressionsi.e., that the events experienced by a pregnant female are reflected in the constitution of the child to be born. How ancient these beliefs are is suggested in the Book of Genesis, in which Laban produced spotted or striped progeny in sheep by showing the pregnant ewes striped hazel rods. Another such belief is telegony, which goes back to Aristotle; it alleged that the heredity of an individual is influenced not only by his father but also by males with whom the female may have mated and who have caused previous pregnancies. Even Darwin, as late as 1868, seriously discussed an alleged case of telegony: that of a mare mated to a zebra and subsequently to an Arabian stallion, by whom the mare produced a foal with faint stripes on his legs. The simple explanation for this result is that such stripes occur naturally in some breeds of horses.

All these beliefs, from inheritance of acquired traits to telegony, must now be classed as superstitions. They do not stand up under experimental investigation and are incompatible with what is known about the mechanisms of heredity and about the remarkable and predictable properties of genetic materials. Nevertheless, some people still cling to these beliefs. Some animal breeders take telegony seriously and do not regard as purebred the individuals whose parents are admittedly pure but whose mothers had mated with males of other breeds. Soviet biologist and agronomist Trofim Denisovich Lysenko was able for close to a quarter of a century, roughly between 1938 and 1963, to make his special brand of Lamarckism the official creed in the Soviet Union and to suppress most of the teaching and research in orthodox genetics. He and his partisans published hundreds of articles and books allegedly proving their contentions, which effectively deny the achievements of biology for at least the preceding century. The Lysenkoists were officially discredited in 1964.

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Gene Therapy Initiative – gilbertfamilyfoundation.org

Exploring Nonsense Suppressionas a Treatment for NF1

This project aims to find compounds that suppress the effects of nonsense mutations in the NF1 gene, thus restoring neurofibromin protein expression and function in NF1 patients.

David Bedwell, PhDUniversity of Alabama, Birmingham

Bruce Korf, MD, PhDUniversity of Alabama, Brimingham

Mark Suto, PhDSouthern Research

This project will resolve two primary challenges applying gene therapy approaches to NF1 by using an innovative strategy to engineer new viruses that targets tumor initiating cells and CRISPR-based genome editing to restore the mutated NF1 gene. Using a unique team with complimentary expertise, this venture applies some of the most exciting modern biotechnologies to NF1.

Charles Gersbach, PhDDuke University

David V. Schaffer, PhDUniversity of California, Berkeley

David G. Kirsch, MD, PhDDuke University

Ataluren is a drug that can suppress protein synthesis termination at premature nonsense codons to produce essential proteins in patients with Duchenne muscular dystrophy. This project aims to evaluate its effect on mouse cells with an NF1 gene that harbors nonsense mutations.

Allan Jacobson, PhDUniversity of Massachusetts

This project proposes using nanoparticles to deliver 1) key coding regions of NF1 gene (cDNA) that will make neurofibromin protein, and 2) gene-editing regents to directly correct the mutation that causes NF1 in a patient derived NF1 rat model. If successful, the new system will provide essential pre-clinical data and lay the foundation for clinical trials using nanomedicine to treat NF1 disease.

Robert Kesterson, PhDUniversity of Alabama, Birmingham

Jiangbing Zhou, PhDYale University

This project will bioengineer trans-acting ribozymes, RNA molecules with catalytic properties similar to protein enzymes, to target faulty transcripts of the NF1 gene that fail to translate functional neurofibromin. NF1 mouse models with patient specific mutations that are amenable to ribozyme-mediated correction will be developed for subsequent animal studies.

Andr Leier, PhD University of Alabama, Birmingham

Ulrich Muller, PhDUniversity of California, San Diego

The mutation of one gene, e.g. NF1, often makes other genes that are not normally required for cell survival vulnerable to inactivation. This project aims to kill cells that have inactivated both copies of the NF1 gene. Using CRISPR/CAS9 technology, genes that become essential for the survival of cells with inactivated both copies of the NF1 gene will be identified, particularly those for which an FDA-approved drug is already available.

Eric Pasmant, PharmD, PhDUniversity Paris Descartes

Raphal Margueron, PhDInstitut Curie

This project seeks to develop two new NF1 drug candidates by developing and characterizing multiple potential therapeutics in parallel within fourteen research laboratories. AAV vectors for delivery and zinc finger protein and antisense oligonucleotides to upregulate NF1 expression will also be used when evaluating the efficacy of different therapeutic modalities.

Miguel Sena-Esteves, PhDUniversity of Massachusetts

Scot Wolfe, PhDUniversity of Massachusetts

Matthew Gounis, PhDUniversity of Massachusetts

Jonathan Watts, PhDUniversity of Massachusetts

Xandra Breakefield, PhDMassachusetts General Hospital

Casey Maguire, PhDMassachusetts General Hospital

Antisense directed gene therapy, or more specifically exon skipping, causes cells to skip over faulty pieces of the genetic code, leading to a truncated, but still functional, protein. This project aims to identify exons within the NF1 gene that may be skipped while still maintaining gene function and then develop antisense oligonucleotides to enable modulation of expression.

Deeann Wallis, PhDUniversity of Alabama, Birmingham

Linda Popplewell, PhDRoyal Holloway University of London

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Scientists engineer new CRISPR platform for DNA targeting …

A team that includes the scientist who first harnessed the revolutionary CRISPR-Cas9 and other systems for genome editing of eukaryotic organisms, including animals and plants, has engineered another CRISPR system, called Cas12b. The new system offers improved capabilities and options when compared to CRISPR-Cas9 systems.

In a study published today in Nature Communications, Feng Zhang and colleagues at the Broad Institute of MIT and Harvard and the McGovern Institute for Brain Research at MIT, with co-author Eugene Koonin at the National Institutes of Health, demonstrate that the new enzyme can be engineered to target and precisely nick or edit the genomes of human cells. The high target specificity and small size of Cas12b from Bacillus hisashii (BhCas12b) as compared to Cas9 (SpCas9), makes this new system suitable for in vivo applications. The team is now making CRISPR-Cas12b widely available for research.

The team previously identified Cas12b (then known as C2c1) as one of three promising new CRISPR enzymes in 2015, but faced a hurdle: Because Cas12b comes from thermophilic bacteria which live in hot environments such as geysers, hot springs, volcanoes, and deep sea hydrothermal vents the enzyme naturally only works at temperatures higher than human body temperature.

We searched for inspirations from nature, Zhang says. We wanted to create a version of Cas12b that could operate at lower temperatures, so we scanned thousands of bacterial genetic sequences, looking in bacteria that could thrive in the lower temperatures of mammalian environments.

Through a combination of exploration of natural diversity and rational engineering of promising candidate enzymes, they generated a version of Cas12b capable of efficiently editing genomes in primary human T cells, an important initial step for therapeutics that target or leverage the immune system.

This is further evidence that there are many useful CRISPR systems waiting to be discovered, said Jonathan Strecker, a postdoc in the Zhang Lab, a Human Frontiers Science program fellow, and the studys first author.

The field is moving quickly: Since the Cas12b family of enzymes was first described in 2015 and demonstrated to be RNA-guided DNA endonucleases, several groups have been exploring this family of enzymes. In 2017 a team from Jennifer Doudnas lab at the University of California at Berkeley reported that Cas12b from Alicyclobacillus acidoterrestris can mediate nonspecific collateral cleavage of DNA in vitro. More recently, a team from the Chinese Academy of Sciences in Beijing reported that another Cas12b, from Alicyclobacillus acidiphilus, was used to edit mammalian cells.

The Broad Institute and MIT are sharing the Cas12b system widely. As with earlier genome editing tools, these groups will make the technology freely available for academic research via the Zhang labs page on the plasmid-sharing website Addgene, through which the Zhang lab has already shared reagents more than 52,000 times with researchers at nearly 2,400 labs in 62 countries to accelerate research.

Zhang is a core institute member of the Broad Institute of MIT and Harvard, as well as an investigator at the McGovern Institute for Brain Research at MIT, the James and Patricia Poitras Professor of Neuroscience at MIT, and an associate professor at MIT, with joint appointments in the departments of Brain and Cognitive Sciences and Biological Engineering.

Support for this study was provided by the National Human Genome Research Institute, the National Institute of Mental Health, the National Heart, Lung, and Blood Institute, the Poitras Center for Psychiatric Disorders Research, and the Hock E. Tan and K. Lisa Yang Center for Autism Research. Feng Zhang is an investigator with the Howard Hughes Medical Institute.

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Hormone Clinic – Troches – Hormone Clinic

The Troche provides a means to deliver custom made medication in small doses directly into the blood stream.

Troches can be mixed so that each individual troche contains a combination of various natural bio-identical hormones in small doses. For example, a troche can be made containing a mixture of any of the hormones, eg:estrogen,progesteroneandtestosteronein any possible doses according to your needs. This combination is used to treat the symptoms ofmenopause.

Small doses of testosterone are useful in menopause for depression, to enhance energy levels, mood and libido without causing side effects.

Troches containing natural progesterone alone are helpful for premenstrual syndrome and can be taken during the latter half of the menstrual cycle to alleviate depression, migraine, nausea and basically all those PMT symptoms that occur in the peri menopause.

Menopausal women who have had a hysterectomy can benefit from troches containing natural bio-identical estrogens, progesterone and testosterone. Even though the uterus may not be present, in the case of hysterectomy, progesterone is still essential to balance the estrogen component and stop estrongenic side effects. Your requirements should be determined with a blood test to measure your sex hormones we recommend tests for blood estrogen, progesterone and testosterone .

Troches can be made palatable, by making them in different flavours. Each troche is made up on an individual basis and the whole process takes a few days.

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What is VetStem Regenerative Medicine? | Why Use Adipose …

VetStem Technology: Summary

VetStem Regenerative Cell Therapy is based on a clinical technology licensed from Artecel Inc. Original patents are from the University of Pittsburgh and Duke University.

Adipose-derived regenerative cells are:

VetStem Regenerative Cell (VSRC) therapy delivers a functionally diverse cell population able to communicate with other cells in their local environment. Until recently, differentiation was thought to be the primary function of regenerative cells. However, the functions of regenerative cells are now known to be much more diverse and are implicated in a highly integrated and complex network. VSRC therapy should be viewed as a complex, yet balanced, approach to a therapeutic goal. Unlike traditional medicine, in which one drug targets one receptor, Regenerative Medicine, including VSRC therapy, can be applied in a wide variety of traumatic and developmental diseases. Regenerative cell functions include:

In general, in vitro studies demonstrate that MSCs limit inflammatory responses and promote anti-inflammatory pathways.

Multiple studies demonstrate that MSCs secrete bioactive levels of cytokines and growth factors that support angiogenesis, tissue remodeling, differentiation, and antiapoptotic events.25,28 MSCs secrete a number of angiogenesis-related cytokines such as:28

Adipose-derived MSC studies demonstrate a diverse plasticity, including differentiation into adipo-, osteo-, chondro-, myo-, cardiomyo-, endothelial, hepato-, neuro-, epithelial, and hematopoietic lineages, similar to that described for bone marrow derived MSCs.22 These data are supported by in vivo experiments and functional studies that demonstrated the regenerative capacity of adipose-derived MSCs to repair damaged or diseased tissue via transplant engraftment and differentiation.6,9,30

Homing (chemotaxis) is an event by which a cell migrates from one area of the body to a distant site where it may be needed for a given physiological event. Homing is an important function of MSCs and other progenitor cells and one mechanism by which intravenous or parenteral administration of MSCs permits an auto-transplanted therapeutic cell to effectively target a specific area of pathology.

Adipose-derived regenerative cells contain endothelial progenitor cells and MSCs that assist in angiogenesis and neovascularization by the secretion of cytokines, such as hepatic growth factor (HGF), vascular endothelial growth factor (VEGF), placental growth factor (PGF), transforming growth factor (TGF), fibroblast growth factor (FGF-2), and angiopoietin.25

Apoptosis is defined as a programmed cell death or cell suicide, an event that is genetically controlled.35 Under normal conditions, apoptosis determines the lifespan and coordinated removal of cells. Unlike during necrosis, apoptotic cells are typically intact during their removal (phagocytosis).

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Stem Cell Transplants in Cancer Treatment – National …

Stem cell transplants are procedures that restore blood-forming stem cells in people who have had theirs destroyed by the very high doses of chemotherapy or radiation therapy that are used to treat certain cancers.

Blood-forming stem cells are important because they grow into different types of blood cells. The main types of blood cells are:

You need all three types of blood cells to be healthy.

In a stem cell transplant, you receive healthy blood-forming stem cells through a needle in your vein. Once they enter your bloodstream, the stem cells travel to the bone marrow, where they take the place of the cells that were destroyed by treatment. The blood-forming stem cells that are used in transplants can come from the bone marrow, bloodstream, or umbilical cord. Transplants can be:

To reduce possible side effects and improve the chances that an allogeneic transplant will work, the donors blood-forming stem cells must match yours in certain ways. To learn more about how blood-forming stem cells are matched, see Blood-Forming Stem Cell Transplants.

Stem cell transplants do not usually work against cancer directly. Instead, they help you recover your ability to produce stem cells after treatment with very high doses of radiation therapy, chemotherapy, or both.

However, in multiple myeloma and some types of leukemia, the stem cell transplant may work against cancer directly. This happens because of an effect called graft-versus-tumor that can occur after allogeneic transplants. Graft-versus-tumor occurs when white blood cells from your donor (the graft) attack any cancer cells that remain in your body (the tumor) after high-dose treatments. This effect improves the success of the treatments.

Stem cell transplants are most often used to help people with leukemia and lymphoma. They may also be used for neuroblastoma and multiple myeloma.

Stem cell transplants for other types of cancer are being studied in clinical trials, which are research studies involving people. To find a study that may be an option for you, see Find a Clinical Trial.

The high doses of cancer treatment that you have before a stem cell transplant can cause problems such as bleeding and an increased risk of infection. Talk with your doctor or nurse about other side effects that you might have and how serious they might be. For more information about side effects and how to manage them, see the section on side effects.

If you have an allogeneic transplant, you might develop a serious problem called graft-versus-host disease. Graft-versus-host disease can occur when white blood cells from your donor (the graft) recognize cells in your body (the host) as foreign and attack them. This problem can cause damage to your skin, liver, intestines, and many other organs. It can occur a few weeks after the transplant or much later. Graft-versus-host disease can be treated with steroids or other drugs that suppress your immune system.

The closer your donors blood-forming stem cells match yours, the less likely you are to have graft-versus-host disease. Your doctor may also try to prevent it by giving you drugs to suppress your immune system.

Stem cells transplants are complicated procedures that are very expensive. Most insurance plans cover some of the costs of transplants for certain types of cancer. Talk with your health plan about which services it will pay for. Talking with the business office where you go for treatment may help you understand all the costs involved.

To learn about groups that may be able to provide financial help, go to the National Cancer Institute database, Organizations that Offer Support Services and search "financial assistance." Or call toll-free 1-800-4-CANCER (1-800-422-6237) for information about groups that may be able to help.

When you need an allogeneic stem cell transplant, you will need to go to a hospital that has a specialized transplant center. The National Marrow Donor Program maintains a list of transplant centers in the United States that can help you find a transplant center.

Unless you live near a transplant center, you may need to travel from home for your treatment. You might need to stay in the hospital during your transplant, you may be able to have it as an outpatient, or you may need to be in the hospital only part of the time. When you are not in the hospital, you will need to stay in a hotel or apartment nearby. Many transplant centers can assist with finding nearby housing.

A stem cell transplant can take a few months to complete. The process begins with treatment of high doses of chemotherapy, radiation therapy, or a combination of the two. This treatment goes on for a week or two. Once you have finished, you will have a few days to rest.

Next, you will receive the blood-forming stem cells. The stem cells will be given to you through an IV catheter. This process is like receiving a blood transfusion. It takes 1 to 5 hours to receive all the stem cells.

After receiving the stem cells, you begin the recovery phase. During this time, you wait for the blood cells you received to start making new blood cells.

Even after your blood counts return to normal, it takes much longer for your immune system to fully recoverseveral months for autologous transplants and 1 to 2 years for allogeneic or syngeneic transplants.

Stem cell transplants affect people in different ways. How you feel depends on:

Since people respond to stem cell transplants in different ways, your doctor or nurses cannot know for sure how the procedure will make you feel.

Doctors will follow the progress of the new blood cells by checking your blood counts often. As the newly transplanted stem cells produce blood cells, your blood counts will go up.

The high-dose treatments that you have before a stem cell transplant can cause side effects that make it hard to eat, such as mouth sores and nausea. Tell your doctor or nurse if you have trouble eating while you are receiving treatment. You might also find it helpful to speak with a dietitian. For more information about coping with eating problems see the booklet Eating Hints or the section on side effects.

Whether or not you can work during a stem cell transplant may depend on the type of job you have. The process of a stem cell transplant, with the high-dose treatments, the transplant, and recovery, can take weeks or months. You will be in and out of the hospital during this time. Even when you are not in the hospital, sometimes you will need to stay near it, rather than staying in your own home. So, if your job allows, you may want to arrange to work remotely part-time.

Many employers are required by law to change your work schedule to meet your needs during cancer treatment. Talk with your employer about ways to adjust your work during treatment. You can learn more about these laws by talking with a social worker.

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How Bone Marrow and Stem Cells are Collected | BMT Infonet

Language English

If you are providing the blood stem cells for a transplant, they will either be collected from your bloodstream (peripheral blood) or from your bone marrow.

The largest concentration of blood stem cells is in your bone marrow. However, the blood stem cells can be moved or "mobilized" out of the bone marrow into the bloodstream (peripheral blood) where they can be easily collected. Most transplants these days use stem cells collected from the bloodstream.

When blood stem cells are collected from the bloodstream, the procedure is called a peripheral blood stem cell collection or harvest.

Prior to the harvest, you will receive injections of a drug such as filgrastim (Neupogen) or plerixifor (Mozobil) over a four to five day period. These drugs move stem cells out of the bone marrow into the bloodstream.

Most people tolerate these drugs well, although mild, flu-like symptoms are common. The symptoms end a few days after the injections stop.

If you are collecting stem cells for your own transplant, chemotherapy drugs may be used to help move the stem cells out of your bone marrow into the bloodstream.

Peripheral blood stem cell collections are done in an outpatient clinic.

The procedure is painless. However, you may feel lightheaded, cold or numb around the lips. Some people feel cramping in their hands which is caused by the blood thinning agent used during the procedure. These symptoms cease when the procedure ends.

The procedure used to collect bone marrow for transplant is called a bone marrow harvest. It is a surgical procedure that takes place in a hospital operating room. Typically it is done as an outpatient procedure.

The amount of bone marrow harvested depends on the size of the patient and the concentration of blood stem cells in your marrow.

Typically one to two quarts of marrow and blood are harvested. While this may sound like a lot, your body can usually replace it in four weeks.

When the anesthesia wears off, you may feel some discomfort in your hip and lower back for several days. The pain is similar to what you would feel if you took a hard fall and bruised your hip. You may find sitting for a long period of time or climbing stairs uncomfortable for a few days. The pain is usually relieved with acetaminophen (Tylenol).

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Best DNA Testing Kits 2019 – Genetic Testing for Ancestry …

How Much Do DNA Testing Kits Cost?Most ancestry DNA kits cost about $100. AncestryDNA, 23andMes Ancestry test and National Geographics Geno 2.0 test all fall nicely into that price point. If youre looking for a bargain, we recommend waiting to buy until your preferred test is on sale, as theyre often available well below their usual price. To get the most for your money, buy an Ancestry or 23andMe kit on sale then upload your Raw data to MyHeritage DNAs database, which is free.

How Accurate Are DNA Ancestry Tests?Our testers took multiple DNA ancestry tests, and the services returned slightly different results for each person. This doesnt necessarily mean that any one company is more accurate than another. Every DNA testing service uses its own algorithm and data set different reference populations drawn from different databases. Nacho Esteban of 24Genetics told us, Ancestry is not an exact science. The top five companies in the world would show very similar results when talking about continents; the similarity is smaller when talking about countries. In regional ancestry, some border regions are difficult to identify and sometimes there may be discrepancies. So we cannot take the information as something 100% sure. But at the end, it gives a great picture of where our ancestors were from.

In our tests, we did find consistency across our results on the continental level. For example, my ancestry is exclusively East Asian, but 23andMe breaks it down into 80 percent Korean, 10.5 percent Japanese and 0.8 percent Chinese, with the remaining 8.7 percent in broader categories. However, Ancestry reports my DNA as 98 percent Korean and Northern Chinese, with only 2 percent Japanese. National Geographic places 85 percent of my ancestry from Northeastern Asia and 14 percent from the South China Sea region, with my DNA most closely matching the Korean and Japanese reference populations.

Database Size & Reference PopulationsWhen asked about how database size affects ancestry results, David Nicholson, co-founder of Living DNA, told us, The tests absolutely rely on the reference database. If you have Polish ancestry but there are no people in the database who are Polish, then what the test will do is show what the next closest group is next to Polish, like German or Eastern European ancestry. Each ancestry DNA service has its own sample database and reference panel made of the DNA samples collected from their users and information collected from sources like the 1000 Genomes Project. The database consists of all this information collectively. A reference panel is made of certain curated samples with known family history and roots in a specific place. The services use insights gleaned from the reference panel to give you geographical ancestry results. In theory, a larger database leads to more information available to create a good reference panel, which then leads to better results for customers.

In testing, we found that many tests have much more specific and detailed results for European ancestry than anywhere else. This is due more to the diversity of the database than size. For example, AncestryDNA has the largest database with over 10 million samples yet results for Asian ancestry are markedly less specific than results from several companies with much smaller databases, including 23andMe and Living DNA. Instead of pulling reference samples directly from the existing database, however, many companies seek out high quality data with special research projects. 23andMe, for example, offers its Global Genetics project, which sends free kits to people with all four grandparents born in certain countries that are underrepresented in the database.

Should I Buy a DNA Test?

Direct-to-consumer DNA tests are still relatively new. The first ancestral DNA test launched in 2001 by FamilyTreeDNA, but companies didnt start genotyping autosomal DNA until 2007. Still, tests and results have come a long way since then, with much lower prices and streamlined sample collection, registration and results. If youre still on the fence about whether or not to buy a DNA ancestry test for yourself or as a gift, here are a few things to consider.

Why You Should Test Your DNA

DNA tests offer a wealth of insights into your connections to family, history and geographical locations. They both entertain and encourage you to dig into what you know about yourself. The tests make great gifts to bring you closer to your family and involve you and your family in the development of a cutting-edge science at the same time. Beyond that, the information is extremely useful for adoptees, people looking for lost relatives, genealogists and for medical science.

Many DNA databases, including Ancestry, 23andMe and MyHeritage DNA, have family search features, which match your DNA with that of potential relatives. These features help users searching for family, including adoptees and children conceived through sperm donations. Almost every DNA testing service we interviewed for this article had a story ready about how its service facilitated a heartwarming family reunion. Like these from Ancestry, this one from MyHeritage andthis one from 23andMe. Because many DNA services also have resources like family tree builders, the tests work in tandem with genealogical research.

For better ancestry and medical insights, you should encourage family members, especially parents and grandparents, to take a DNA test as well. If your family is from a specific geographical location for generations, your samples could potentially improve the service's reference panel, in turn improving results for everyone. If youre female and take a test from 23andMe or LivingDNA, you can view paternal haplogroup information, and you get more information when one of your male family members takes a test as well.

Why You Shouldnt Test Your DNA

There are several examples of people finding out a little more than they wanted because of results from a direct-to-consumer DNA test. There are Facebook communities full of people who found out they have different parents. Theres little you can do to prepare for that shock, though most services with family matching features do include warnings about unexpected discoveries in their terms of service. You can also opt to not receive family matches if youre simply looking for medical or geographical ancestry information.

Another reason you may want to avoid taking a DNA test is if youve committed a crime or you know someone closely related to you has committed a crime. Law enforcement has recently taken to testing DNA evidence from crime scenes through open DNA databases like GEDmatch after successfully solving several cold cases after the arrest of the Golden State Killer in April 2018. There are several open DNA databases floating around the internet, where people upload their raw DNA data after taking another test like 23andMe or Ancestry. Most companies do not release database information to law enforcement, however, a recent study estimates that up to 60% of Americans with European heritage can be identified via third-cousin-or-closer DNA using publicly available data.

DNA Traits

In addition to showing geographic ancestry percentages, some direct-to-consumer DNA tests also include insights about physical traits like hair and eye color. With 23andMe, this trait information is mostly available in the upgraded Ancestry + Health kit, but some interesting tidbits can be found in the Your DNA Family report, which is available if you opt to participate in the DNA Relatives service. This report tells you interesting information, such as that your DNA relatives are 32 percent more likely to own a cat or 11 percent less likely to have lived near a farm when they were young. DNA Passport by Humancode offers information about more than 20 physical traits, from appearance to grip strength. Ancestry DNA recently added its AncestryDNA Traits upgrade for $10, and it lets customers who have already taken one of its tests unlock information about 18 genetically influenced traits, including bitter taste perception, freckles and cilantro aversion.

Most of this trait data tells you things you already know, like your hair and eye color, but it is fun to see them compared to your genetic relatives and the world at large. We also found it fascinating to learn more about how these physical traits are genetically determined. For example, finger length ratio is determined by hormonal exposure in the womb, with higher testosterone exposure resulting in a better chance of having a longer ring finger. 23andMes Health report for finger length ratio looks at 15 gene markers to estimate your likelihood of having longer ring fingers or index fingers.

Types of DNA

Of the 23 pairs of chromosomes in the human genome, 22 are autosomes. Most direct-to-consumer DNA tests look primarily at your autosomal DNA to determine your geographic ancestry percentages. This DNA is a mix of inherited DNA segmentshalf from each parent. Because everyone inherits at least one X chromosome from their mother, DNA tests often include the X chromosome in autosomal testing, though the X chromosome is not an autosome.

The 23rd pair of chromosomes is comprised of sex chromosomes X and Y chromosomes that determine whether youre male (XY) or female (XX). Traits like red-green color blindness, male pattern baldness and hemophilia are specifically linked to X or Y chromosomes and are called sex-linked characteristics. All of those examples, and most other sex-linked traits, are X-linked and more common in males, who only have one X chromosome. Many DNA tests isolate Y DNA in males to show consumers their paternal haplogroup. Since the Y chromosome is directly inherited from father to son, it is possible to trace direct paternal lineage for many generations.

Similarly, mitochondrial DNA, or mtDNA, is used by direct-to-consumer DNA tests to trace your direct maternal lineage and determine maternal haplogroups. While most DNA lives in your cells' nuclei, mtDNA lives in the mitochondria. Mitochondria are the cells' powerhouses their 37 genes are necessary for cellular energy production and respiration. Previous research suggested that mtDNA is inherited directly from your mother, but a recent study found that biparental mtDNA may be more common. This discovery may affect maternal haplogroup testing in DNA tests in the future, but for now, its safe to assume your results are correct.

Genotyping vs. Sequencing

Most of the services we tested use genotyping to read your DNA. Genotyping looks for specific markers in your genetic code. For something like ancestry testing, genotyping is effective because it identifies known variants in your DNA. Scientifically speaking, genotypings weakness is that it can only recognize previously identified markers. This is one reason DNA tests accuracy relies so heavily on the DNA database size; there must be enough information available and identified genetic variants in the database to recognize new customers markers.

A few of the DNA tests we tested, including the National Geographic Geno 2.0, use genetic sequencing instead of genotyping. Sequencing is newer in the mainstream direct-to-consumer DNA testing market, as it used to cost more and take much longer to sequence a persons DNA. Sequencing identifies the exact makeup of a certain piece of DNA be it a short segment or the whole genome. The Helix tests sequence the Exome, which are the parts of the genome responsible for protein production, plus several other regions of interest. DNA sequencing gives more information overall and has more uses in medical testing than genotyping. In the future, more DNA kits may move from genotyping to DNA sequencing as the technology gets cheaper and faster, but for now both are effective ways to look into your geographic ancestry.

DNA Testing Your Pet

Beyond ancestry tests, there are at-home DNA kits available for everything from vitamin regimens to dating sites. There are even DNA test kits for your furry friends. Companies like Embark, Wisdom Panel and many others offer genetic health risk screenings, trait analyses and breed percentage information for dogs. These canine ancestry tests allow you to confidently state that your mutt is part Irish wolf hound and give you key information about your pets heritage for insights into potential health issues. For example, if you found out one of your rescue dogs parents was likely a purebred boxer, you could speak with your vet about breed-specific needs. Or if you find out your cute new puppy of indeterminate origin is mostly Bernese mountain dog, you can expect it to grow very large.

Like direct-to-consumer DNA tests for humans, these dog kits require a DNA sample, usually a cheek swab. They also fall in a similar price range, from $60 up to $200 for services with health information in addition to breed identification. Because there are so many canine DNA tests to choose from, we recommend shopping based on the companys sample database and the number of breeds the company tests for.

If youre looking for genetic information about your feline friend, there are fewer options, though Basepaws DNA CatKit promises information about your cats breed and traits with just a hair sample. It also offers swab kits for hairless cats. The company is fairly new and claims that results take up to four months, though most are delivered within eight to 12 weeks. The kit costs $95 and also tells you how closely related your kitty is to wild cats like lions, tigers and (bears, oh my!) ocelots.

DNA Testing for Children

Since genome sequencing is still a relatively young science, we don't recommend submitting your childs DNA to direct-to-consumer companies. We do encourage consulting with your doctor about genetic testing for your child. Due to some concerns with the DNA testing industry, the choice to have ones genes sequenced by a private company should be made with informed consent. Those concerns are magnified when applied to children, who cannot make their own decisions regarding the unlikely potential risks or privacy concerns.

Once your genetic information is out there, its difficult to undo. Also, once you know something about yourself, its impossible to un-know. Revelations such as having different parents than you expected or finding unknown half-siblings are difficult to process at any age, but its particularly troubling for kids. However, you can always simply opt out of family matching features.

Similarly, on the health side, finding out your child has a gene connected to cancer or another disease can induce unnecessary anxiety, especially since a genetic predisposition to a certain disease does not always guarantee a diagnosis.

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Invitae Genetics is rolling out personal genetic testing …

If the future of healthcare is in your DNA, there's a war brewing over how to harness the information it contains without causing harm to patients.

Today, there are two main ways to take a peak at your genes: either by getting a costly but complete genetic workup through a doctor, or by opting for a more affordable at-home test like those sold by 23andMe.

Clinicians and advocates criticize the at-home approach, which they say prioritizes convenience over privacy and long-term health. But entrepreneurs counter that the at-home approach lets more people access information.

A true hybrid approach something that combines the benefits of comprehensive testing with the convenience of at-home tests while still keeping your data safe and private has yet to have a sizeable impact.

Read more: Genetic testing is the future of healthcare, but many experts say companies like 23andMe are doing more harm than good

That's where San Francisco-based genetic information company Invitae hopes to make a splash.

The company will soon let patients order a personal genetic test online through a genetic counselor or physician, Invitae CEO Sean George said last week at the J.P. Morgan Healthcare Conference. The company's tests are currently only available from a clinician who orders the test on a patient's behalf.

"We now in 2019 will focus on removing the barriers of access to [genetic] information and providing support for that individual every step of the way," George said during a presentation last week.

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Invitae has sequenced the genes of roughly half a million patients. Hollis Johnson/Business Insider Since its first test launched five years ago, Invitae has sequenced the genes of more than half a million patients. The company focused on diagnostic genetic testing for patients with conditions like cancer, heart disease, and rare disorders, as well as infertility and pregnancy. It catered to physicians and genetic counselors who would order the tests on behalf of their patients.

But as genetic information becomes increasingly important in healthcare, the Invitae team has begun to work on making its tests more accessible to more people.

Patients will be able to order genetic tests online through a clinician by this summer, George said. Nearly any test on Invitae's clinical menu will be available this way, making Invitae one of the first companies to offer wider access to clinical testing for an array of conditions and inherited health risks.

Unlike at-home genetic tests, Invitae's tests are clinical grade and will not require patients to follow-up their results with confirmation testing, a company spokesperson told Business Insider.

23andMe, perhaps the most widely-recognized name in genetic testing, sells its $199 'Health and Ancestry' kits in pharmacies or online without any input from a clinician. Because they're offered without a clinician's input, however, 23andMe's tests are not considered clinical grade. As a result, both the company and federal regulators instruct customers to confirm any health findings with a separate clinical-grade test.

Importantly, Invitae requires a physician or genetic counselor to be involved in all of its testing. Their role is to help translate complex genetic results into useful health guidance, Invitae CEO Sean George said.

Say you received a result that said you were at a high risk of an arrhythmia, or an irregular heartbeat. The genetic variants for this condition can be very difficult to interpret alone. While one variant could suggest to an expert that you're in immediate need of a pacemaker, another variant might simply require monthly check-ins with a physician. But only an expert can reliably tell you which variant you have and what to do next.

"It's important to us that they have somebody that can walk them through the results and immediately get them in touch with a specialist," George told Business Insider in November.

Several experts recently echoed George's sentiment, telling Business Insider last week that failing to include a physician or genetic counselor with a genetic test is confusing at best and harmful at worst. That's something George has been thinking about for a long time.

"One of the questions we ask ourselves at Invitae is how we get this information to patients responsibly," George said.

In addition to Invitae, several other companies are also beginning to experiment with new hybrid models for genetic testing. Color Genomics, for example, lets you order a genetic test through an independent physician who can help translate the findings remotely.

And Nebula Genomics says you can get your entire genome sequenced, own the data set, and earn digital money by sharing it.

Another approach is being pioneered by LunaDNA, which is offering to pay people for their genetic information in the form of shares of LunaDNA.

George said that while he hopes Invitae's new initiative will help more people get access to their genetic information earlier, he wants to also ensure that people are able to act on the guidance they receive.

"Our mission is to get it in more people's hands, but we aren't interested in unleashing a whole bunch of information on folks and providing no way to do anything tangible with it," he said.

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Unwanted side effects of (bioidentical) hormone …

The use of bioidentical hormones got a lot of press after Suzanne Somers (Threes Company cast member and promoter of the ThighMaster) began touting them as an alternative to synthetic hormone replacement. I wholeheartedly agree that bioidentical hormones are preferable to synthetic hormone replacement therapy (HRT). Recall the large experiment on the female population known as the Womens Health Initiative Postmenopausal Hormone Therapy Trials. If you arent familiar with the results of that study, here is a summary provided by the National Institutes of Health:

Compared with the placebo, estrogen plus progestin resulted in:

Increased risk of heart attackIncreased risk of strokeIncreased risk of blood clotsIncreased risk of breast cancerReduced risk of colorectal cancerFewer fracturesNo protection against mild cognitive impairment and increased risk of dementia (study included only women 65 and older)

Compared with the placebo, estrogen alone resulted in:

No difference in risk for heart attackIncreased risk of strokeIncreased risk of blood clotsUncertain effect for breast cancerNo difference in risk for colorectal cancerReduced risk of fracture(Findings about memory and cognitive function are not yet available.)

Just because synthetic hormones come with proven risk, it seems that people have decided bioidentical hormones are totally fine to take. Bioidentical hormones are crafted to be the exact molecular structure of the hormone(s) your body produces. Synthetic hormones, on the other hand are not. Synthetic hormones are typically a bit different from the exact structure that your body makes because that way it can be patented by the manufacturer.

The purpose of this article is not necessarily to compare and contrast synthetic from bioidentical HRT; but to alert you as to how the body responds when bioidentical (and synthetic) hormones are taken. Well, really to alert you on the downside consequences of taking ANY hormones. The physiology is simple and logical. It can be more in depth, but Ill focus on the basics. By the way, Im referring to the pathways of the most commonly replaced hormones, steroid (e.g.: estrogen, testosterone, progesterone, cortisol, DHEA, etc.) and thyroid hormones.

Most hormones work in the body via a negative feedback loop. This means that as the level of a hormone rises, a signal is mediated that ceases that hormones production and release; in order to prevent the production of the hormone from getting out of control. Lets begin with an example using thyroid hormone.

The three main glands involved in thyroid hormone production are the hypothalamus, pituitary and thyroid. The hypothalamus releases thyroid releasing hormone (TRH), which stimulates the pituitary gland to release thyroid stimulating hormone (TSH), which in turn stimulates the thyroid gland to manufacture and release thyroid hormones (thyroxine or T4 and triiodothyronine or T3). Once the thyroid hormone begins to do its job throughout the body, production begins to decline, so as not to produce too many hormones. So, as the level of thyroid hormone increases, the levels of TRH and TSH decrease. Its called a negative feedback loop because the rise in hormone levels results in a decreased production; as opposed to a positive feedback loop where a rise in hormone levels would produce an even greater rise in the level of that same hormone. The only example of a hormone that works on a positive feedback loop that I can think of is oxytocin.

Because these hormones work this way, you may be able to guess what happens when you are exposed to (i.e.: ingest) exogenous hormones. Exogenous (as opposed to endogenous) refers to those taken in from outside the body, and can be any type of hormone. So, if you take a hormone, you can be sure that those negative feedback loops will still function as usual. The resultyour body stops (or significantly slows) its own production of these hormones. Whats wrong with that? Eventually, youll be dependent on these hormones as your glands have gone to sleep, because someone else is doing their job. Its simply not necessary for the glands to have to do anything.

So if you stop taking them, it may be extremely difficult to get your bodys own production back up to par. Now, considering people often take hormones because theyre not producing enough on their own in the first place, you can imagine how difficult it would be to begin the production process after taking exogenous hormones and suppressing your hormone production even further. Therefore, people usually become completely dependent on hormones, bioidentical or not. In general, as long as youre okay with taking a hormone for the rest of your life, there is no need to worry. However, most (if not all) of my patients shun that idea.

The next issue is that of hormone receptor insensitivity. Generally speaking, each hormone docks into a receptor on its target cell. Its as if the receptor is the lock and the hormone is the key. Once the cell door opens, the hormone goes on to carry out its function (usually turning on or off genes). The problem with bombarding the cells with large doses of a hormone is that eventually its as if the cell decides to change the lock on the door. The result is that it is harder and harder for the hormone to open the cell door, and therefore more and more of the hormone is needed each successive time you want to make an effect on the cell/genes. Its almost as if you need enough hormone to knock the cell door down, because it doesnt want to open. This is especially prevalent with the use of hormone creams (usu. progesterone). However, if you make no lifestyle changes it typically happens with any hormone. Thats why people on thyroid hormone often have to continue increasing the dose to get the same effect; the same goes for those who take insulin. Have you ever known of diabetic or person with hypothyroidism (except for autoimmune thyroid disease/Hashimotos) that had to decrease their dose, without making lifestyle changes? So, taking a hormone for the rest of your life may not even do the trick, especially insulin. You may be familiar with how well diabetics fare without changing their lifestyle, and continually increasing their doses of insulin. By the way, hormone receptor sites often run out of the vitamin and minerals that are necessary to allow them to function properly, due to the constant bombardment of hormones they are subject to in these cases.

This is not to say that no one should be on HRT, bioidentical or synthetic. There is a time and place for everything. And when these hormones are necessary, they can be miraculous. The big question is: When are they necessary? Thats a debatable issue and can certainly vary between individuals. So I am not absolutely against HRT, though I definitely prefer bioidentical over synthetic when possible.

The point Im trying to get across is that I wouldnt recommend anyone start with HRT, unless they are in a very unmanageable state. In these instances, one option may be to start with HRT to prime the pump and then eventually wean off them. Unfortunately, with all the books written about HRT and the attention it gets these days, many people (and doctors) go straight for hormones (with or without lab tests). Dont get me wrong, chances are youll feel like a million bucks if you take hormones that you are deficient in, or insensitive to. But dont forget to ask the million dollar question just because you feel like a million bucks: How long does that last? Well, there is no single answer to that question because everybodys condition and lifestyle is a bit different. But, from what Ive seen, it lasts about six months at best, before they have to adjust the dose upward. You may eventually find yourself always having to increase the dose to get the same effect. And finally, your cells just may not respond adequately, despite the dose. Thats not say there is no hope though.

Im currently working with a patient who had low testosterone and used testosterone replacement therapy for over a year. Sure enough, he had to continually increase the dose, until it eventually stopped giving him the results he needed (i.e.: absence of musculoskeletal pain, strength, libido, and an erection). In this case (and others), I determine if the hypothalamus, pituitary, gonads (when it comes to testosterone), and/or cell receptors need support. Fortunately, in the above mentioned case, the patient got immediate results that according to him, showed via the number of plates he kept adding on the machines at the gym.

In some cases, it may not be easy to get everything back up and running like new. But with the proper nutritional support and lifestyle improvements, it certainly is an attainable goal. The willingness of the patient to change their lifestyle and the length of time the person has been on hormones are two very important factors that will help to determine the outcome. Fortunately, I havent seen a lost cause yet; but I sure have seen people feeling miserable after the hormones stop giving the desired effect. Remember, theres no such thing as a free lunch!

Not to go into politicsbut Im a big advocate of being able to buy supplements over-the-counter. Although I truly believe that hormones should only be dispensed through licensed health care practitioners who know how to use them.

PS: There are more problems associated with HRT (bioidentical or not) than what I mentioned above. For example, many men who take testosterone can eventually wind up converting it into estrogen (just about the opposite effect they are looking for)thats enough on that for now.

PSS: Im not saying that bioidentical hormones are never necessary. They certainly can be in some instancesjust consider the potential side-effects and work with a licensed, competent, qualified health care professional who knows how to use them appropriately. They can be very useful to prime the pump when other lifestyle changes are implemented.

Dr. Robert DAquila NYC Chiropractor Applied Kinesiology

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