Archive for February, 2016

Pituitary tumors (adenomas) that do not secrete active hormones are called clinically nonfunctioning pituitary adenomas. Most are large (macroadenomas), measuring more than one centimeter in size at the time of diagnosis. Patients start experiencing symptoms when the large tumor compresses the optic nerves, leading to vision loss, or the loss of normal pituitary function.

The UCLA Pituitary Tumor Program offers comprehensive management of clinically nonfunctioning pituitary adenomas. Our physicians have years of experience in diagnosing, treating and managing pituitary conditions.

Use these links to explore more about clinically nonfunctioning pituitary adenomas:

Clinically nonfunctioning pituitary adenomas make up about half of pituitary adenomas. The vast majority of them are benign.

There are several possible reasons why nonfunctioning pituitary adenomas could occur:

The most common symptoms are due to the large tumor compressing nearby structures, leading to:

Increased compression of the normal gland can cause hormone insufficiency, called hypopituitarism. The symptoms depend upon which hormone is involved.

More severe hypopituitarism can lead to hypothyroidism or abnormally low cortisol levels, which may be life threatening. Symptoms of severe hypopituitarism include:

Changes in hormonal function can cause electrolyte imbalance in the blood, typically low sodium levels (hyponatremia). Symptoms could include:

Imaging scans are one method doctors use to diagnose clinically nonfunctioning pituitary adenomas. We will also order hormone tests to evaluate the levels of pituitary hormone, confirming that there is no evidence of hormone production by the tumor.

Your doctor will conduct a thorough physical examination and ask you about your symptoms and medical history. He or she will then order tests as necessary, including:

MRI imaging allows us to detect whether there are tumors present. Your doctor will use a special MRI pituitary protocol to best visualize the tumor.

There are other tumors that produce symptoms similar to that of a pituitary adenoma. Your doctor will want to rule out these other tumors before confirming a diagnosis. Tumors that mimic the symptoms of a pituitary adenoma include:

If your symptoms suggest pituitary failure (hypopituitarism), your doctor may order a complete evaluation of the endocrine system. Based on results of these blood tests, you may undergo additional hormonal studies.

Learn more about hormone testing at the UCLA Pituitary Tumor Program.

If you are experiencing vision problems, your doctor will recommend that an experienced ophthalmologist evaluate you. The evaluation should include:

This will determine if you have a loss of peripheral vision.

The UCLA Pituitary Tumor Program offers comprehensive management of all types of pituitary tumors. Treatment options for pituitary adenomas include:

For most patients with nonfunctional adenomas, surgically removing the adenoma is the most effective treatment.

Whether this will lead to a long-term cure depends on the extent of surgical removal, which is related to:

If the surgeon was able to remove the entire tumor, the cure rate is 70 percent to 80 percent. Overall, surgery improves:

If the pituitary adenomas require surgery,typicallythe bestprocedureis througha nasal approach. Our neurosurgeons who specialize in pituitary tumor surgery are experts in the minimally invasive endoscopic endonasaltechnique. This procedure removes the tumor while minimizing complications, hospital time and discomfort. This advanced technique requires specialized training and equipment.

Very large tumors that extend into the brain cavity may require opening the skull (craniotomy) to access the tumor. Our surgeons are also experts in the minimally invasive "key-hole" craniotomy, utilizing a small incision hidden in the eyebrow.

If, after your surgery, some tumor cells remained or regrew, you may be a candidate for radiation therapy or a repeat surgery.

Hormone replacement may be necessary if you have pituitary insufficiency.

Doctors may recommend radiation therapy as a second-line therapy for endocrine-inactive tumors. Focused-beam radiation, named stereotactic radiosurgery, can be effective in controlling tumor growth. In some cases, radiation therapy may cause a loss of pituitary function.

To schedule an appointment with one of our physicians at the Pituitary Tumor Program, please call (310) 825 5111.

You can also email us at pituitary@mednet.ucla.edu

See more here:
Clinically Non-Functioning Pituitary Adenomas | UCLA ...

Cardiac muscle cells or cardiomyocytes (also known as myocardiocytes[1] or cardiac myocytes[2]) are the muscle cells (myocytes) that make up the cardiac muscle. Each myocardial cell contains myofibrils, which are specialized organelles consisting of long chains of sarcomeres, the fundamental contractile units of muscle cells. Cardiomyocytes show striations similar to those on skeletal muscle cells. Unlike multinucleated skeletal cells, the majority of cardiomyocytes contain only one nucleus, although they may have as many as four.[3] Cardiomyocytes have a high mitochondrial density, which allows them to produce adenosine triphosphate (ATP) quickly, making them highly resistant to fatigue.

There are two types of cells within the heart: the cardiomyocytes and the cardiac pacemaker cells. Cardiomyocytes make up the atria (the chambers in which blood enters the heart) and the ventricles (the chambers where blood is collected and pumped out of the heart). These cells must be able to shorten and lengthen their fibers and the fibers must be flexible enough to stretch. These functions are critical to the proper form during the beating of the heart.[4]

Cardiac pacemaker cells carry the impulses that are responsible for the beating of the heart. They are distributed throughout the heart and are responsible for several functions. First, they are responsible for being able to spontaneously generate and send out electrical impulses. They also must be able to receive and respond to electrical impulses from the brain. Lastly, they must be able to transfer electrical impulses from cell to cell.[5]

All of these cells are connected by cellular bridges. Porous junctions called intercalated discs form junctions between the cells. They permit sodium, potassium and calcium to easily diffuse from cell to cell. This makes it easier for depolarization and repolarization in the myocardium. Because of these junctions and bridges the heart muscle is able to act as a single coordinated unit.[6][7]

Cardiac action potential consists of two cycles, a rest phase and an active phase. These two phases are commonly understood as systole and diastole. The rest phase is considered polarized. The resting potential during this phase of the beat separates the ions such as sodium, potassium and calcium. Myocardial cells possess the property of automaticity or spontaneous depolarization. This is the direct result of a membrane which allows sodium ions to slowly enter the cell until the threshold is reached for depolarization. Calcium ions follow and extend the depolarization even further. Once calcium stops moving inward, potassium ions move out slowly to produce repolarization. The very slow repolarization of the CMC membrane is responsible for the long refractory period.[8][9]

Myocardial infarction, commonly known as a heart attack, occurs when the heart's supplementary blood vessels are obstructed by an unstable build-up of white blood cells, cholesterol, and fat. With no blood flow, the cells die, causing whole portions of cardiac tissue to die. Once these tissues are lost, they cannot be replaced, thus causing permanent damage. Current research indicates, however, that it may be possible to repair damaged cardiac tissue with stem cells,[10] as human embryonic stem cells can differentiate into cardiomyocytes under appropriate conditions.[11]

Humans are born with a set number of heart muscle cells, or cardiomyocytes, which increase in size as our heart grows larger during childhood development. Recent evidence suggests that cardiomyocytes are actually slowly turned over as we age, but that less than 50% of the cardiomyocytes we are born with are replaced during a normal life span.[12] The growth of individual cardiomyocytes not only occurs during normal heart development, it also occurs in response to extensive exercise (athletic heart syndrome), heart disease, or heart muscle injury such as after a myocardial infarction. A healthy adult cardiomyocyte has a cylindrical shape that is approximately 100m long and 10-25m in diameter. Cardiomyocyte hypertrophy occurs through sarcomerogenesis, the creation of new sarcomere units in the cell. During heart volume overload, cardiomyocytes grow through eccentric hypertrophy.[13] The cardiomyocytes extend lengthwise but have the same diameter, resulting in ventricular dilation. During heart pressure overload, cardiomyocytes grow through concentric hypertrophy.[13] The cardiomyocytes grow larger in diameter but have the same length, resulting in heart wall thickening.

More:
Cardiac muscle cell - Wikipedia, the free encyclopedia

The skin cell gun, also known as the skin gun or SkinGun, is a medical device that sprays a patient's own self-donated (autologous) stem cells to treat burns and other wounds. The skin gun is used in conjunction with a technique that isolates adult stem cells from a postage stamp-sized sample of the patient's own skin for application to the wound site, where they differentiate into normal skin. This treatment can replace conventional methods of treating severe wounds, such as skin grafting. Studies demonstrate that damaged skin tissue regenerates after skin gun treatment significantly more quickly than after traditional treatment methods. [1][2][3]

The skin gun, along with related cell isolation methodologies, were acquired by RenovaCare, Inc. in 2013.[4] The company continues to develop the technology and treatment protocol for commercial distribution, under the brand names SkinGun and CellMist System respectively. RenovaCare is also exploring opportunities to apply its SkinGun treatments to additional indications, including chronic wounds, pigmentation disorders, and cosmetic applications. [5]

Stem cells from a postage stamp-sized sample of the patient's healthy skin are isolated using a enzymatic tissue processing protocol. The resulting cell suspension is then transferred to a sterile syringe, which is then inserted into the skin gun. Using its unique spray mechanism, the gun uniformly distributes cells directly into the wound. The newly introduced stem cells begin to migrate, multiply, and differentiate, creating new skin tissue in a matter of days.

The entire process from collecting the skin sample, processing it into a cell suspension, and using the skin gun to spray the stem cells takes approximately 1.52 hours from start to finish. Full re-epithelialization can occur in as little as four days, and after a few months the skin will regain its color and texture.[6][7]

Early experimental versions of the device were developed by Dr. Jrg Gerlach and StemCell Systems GmbH in Berlin, Germany. Dr. Gerlach and SCS had already developed cell culture bioreactors for culturing usable liver and other solid organ tissues from stem cells, and were seeking a similar platform to culture living skin. They soon discovered that, compared to other organs, the skin is a special case. A skin wound is itself an accessible environment that provides excellent conditions to culture new skin tissue in vivo. This solves the problems of wait times and special challenges in transplanting delicate, cultured tissue inherent to in vitro skin culture technologies.[8]

Researchers developed novel stem cell isolation techniques that maximize stem cell availability for transplantation.[9] To ensure minimal loss in transplanting the isolated cells, engineers at StemCell Systems designed a deposition device, the skin gun, to gently deliver the cell suspension without exposing cells to harsh forces in conventional spray devices.[9]

The skin gun method was first used experimentally at Charit Universittsmedizin Berlin on a group of nineteen patients. The clinician in that study determined that the results from the skin gun treatment was so significantly better than traditional grafting that he discontinued performing skin grafts on a control group on the basis of medical ethics.[1]

Subsequently several skin gun procedures have been performed at UPMC Mercy Hospital in Pittsburgh, including patients who have been able to leave hospital within four days of treatment.[3]

After an abrasion, cut, burn, or other injury, the body uses several different of biological processes to repair the skin.[10] Wound healing generally has three different stages: the inflammatory stage, the proliferative stage and the remodeling stage.[11]

Once the skin is damaged, a series of interrelated events take place in close succession in order to repair the skin.[12] Within minutes after an injury occurs, blood platelets collect at the site of injury to form a clot. This clot limits bleeding at the injury site.

The inflammatory phase involves increased white blood cell activity, removing bacteria and debris from the wound. Biochemical signals instruct regenerative cells to begin dividing, to create new skin tissues much more rapidly than normal.

The proliferative phase is marked by the formation of new skin tissue at the injury site and the general shrinking and eventual disappearance of the wound.[13] New blood vessels are also established during the healing process. The wound is made smaller by myofibroblasts, which hold on to the edges of the wound and slowly get smaller by a system similar to the contraction of muscle cells.

During the remodeling phase, the skin acquires its permanent texture and unneeded cells are disposed of through apoptosis.

To date skin gun treatment has been used exclusively with second degree burns, though there is strong evidence that the treatment will be successful in treating a variety of skin wounds and skin disorders. Patients with infected wounds or with delay in wound healing are suitable for cell grafting treatment.[3] Third-degree burns, however, completely deprive victims of both their epidermis and dermis skin levels, which exposes the tissue surrounding the muscles. The skin gun has not progressed to the point where it can be used for such advanced wounds, and these patients must seek more traditional treatment methods. The skin gun is generally not used for burn victims with anything less than a second-degree burn either. First degree-burns still maintain portions of the epidermis and can readily heal on their own, thus they do not need this expensive technology.

Currently, the skin gun's applications have not been extended to include the regeneration of skin lost due to other injuries or skin diseases. It is also limited in that it is only effective immediately following the burn incident.[14]

The average healing time for patients with second degree burns is three to four weeks.[15] This is reduced to a matter of days with skin gun treatment.[1][2][3]

Traditional skin grafting can be risky, in that chances for infection are relatively high. The skin gun alleviates this concern because the increased speed in which the wound heals directly correlates to the decreased time the wound can be vulnerable to infection. Because of the rapid re-epithelialization associated with skin gun treatment, harmful side effects that can result from an open wound are significantly reduced.[16] Applying the skin cells is quick and doesn't harm the patient because only a thin layer of the patients healthy skin is extracted from the body into the aqueous spray. The electronic spray distributes the skin cells uniformly without damaging the skin cells, and patients feel as if they are sprayed with salt water.[16]

Because the skin cells are actually the patients own cells, the skin that is regenerated looks more natural than skin grown from traditional methods. During recovery, the skin cells grow into fully functional layers of the skin, including the dermis, epidermis, and blood vessels.[17] The regenerated skin leaves little scarring. The basic idea of optimizing regenerative healing techniques to damaged biological structures demonstrated by the skin gun in the future may also be applied to engineering reconstruction of vital organs, such as the heart and kidneys.[17]

There are major limitations: the method will not work on deep burns that go through bone and muscle, specifically below the dermis. As of 2011, only several dozen patients have been treated; it remains an experimental, not a proven, method. As of 2011, the skin gun was still in its prototyping stage, since it has only treated a dozen patients in Germany and the US, compared to over 50,000 treated with Dermagraft bioengineered skin substitute. There is thus a lack of published peer reviewed clinical evidence, and no knowledge of long-term stability of the newly generated skin.

The skin gun has been featured in numerous books and television shows, including the following examples.

Continue reading here:
Skin cell gun - Wikipedia, the free encyclopedia