April 21, 2006, 7:13 AM CT

Study To Evaluate Regeneration Heart Muscle Lost From Heart Attack

Rush cardiologists are hoping that transplanted stem cells can regenerate damaged heart muscle in those who experience a first heart attack. The study involves an intravenous infusion of adult mesenchymal stem cells from healthy donor bone marrow that might possibly reverse damage to heart tissue.

A unique benefit of the stem cell product is that it is given to patients through a standard IV line. Other therapies require delivery to the site of the disease through catheterization or open surgical procedures, but this one is very simple and easy for the patient.

"A person who has had a single, severe heart attack may survive but can be left with substantial damage to the heart muscle as a result of the blood supply to the heart muscle being cut off during the heart attack. The damaged muscle inhibits the heart's overall ability to pump blood, leading to heart failure," said Rush principal investigator cardiologist Dr. Gary Schaer, head of the Rush Cardiac Catheterization Laboratory. Rush is the only center in Illinois participating in the trial. There are 15 other sites nationwide participating in the study.

He explained that mesenchymal stem cells (MSC) are found in the adult bone marrow and have the potential to develop into mature heart cells and new blood vessels. The MSC cells are derived from normal, healthy adult volunteer bone marrow donors and are not derived from a fetus, embryo or animal. Because they are in an early stage of development, it is believed that they do not trigger an immune response when placed in someone else's body.........

Posted by: Daniel      Permalink         Source

April 20, 2006, 9:37 PM CT

Insights Into Lazy Eye Theory

In a study that challenges conventional thinking about the condition known as lazy eye, scientists at MIT's Picower Institute for Learning and Memory show that it's the quality, not the quantity, of images and light striking the retina that causes one eye to lose function.

The study will appear in the recent issue of the Journal of Neurophysiology.

Amblyopia, or lazy eye, is a developmental disorder characterized by poor or blurry vision in an eye that is structurally normal. The problem is caused by either no transmission or poor transmission of visual images to the brain for a sustained period during early childhood. Amblyopia has been estimated to affect 1 percent to 5 percent of the population.

"It's been known for a long time that if you are born with cataracts in one eye, you will go blind in that eye," said co-author of study Mark Bear, Picower Professor of Neuroscience. "Depriving one eye of crisp images rapidly causes cortical neurons to lose responsiveness to the deprived eye".

While it was thought that inactivity caused the neurons associated with the deprived eye to wither -- a case of "use it or lose it" -- Bear and his colleagues at Brown University report that a blurry image is worse than no image at all.

The conventional therapy for lazy eye is to wear a patch over the good eye in the hope that the weaker eye will get stronger. "It's a zero-sum game," Bear said, "because as the weak eye gets stronger, the strong eye gets weaker. The challenge is to promote recovery of the weak eye without impairing the other eye".........

Posted by: Mike      Permalink         Source

April 20, 2006, 9:16 PM CT

Bringing New Life To Kidney Treatment

Finding how two proteins conspire to get kidney cells to self-destruct when oxygen supplies are low may one day improve dismal mortality rates for ischemic renal failure, scientists say.

Dehydration, low blood pressure, septic shock, trauma or removing a kidney for transplantation can temporarily halt or reduce blood and oxygen supplies, says Dr. Zheng Dong, cell biologist at the Medical College of Georgia.

Ischemia leads to cell suicide or apoptosis, especially in the energy-consuming tubular cells of the kidneys, he says. Fifty percent mortality rates from resulting ischemic renal failure haven't changed in nearly as a number of years, Dr. Dong says.

Tubular cells - which have the daunting daily task of reabsorbing nearly 50 gallons of usuable fluid volume, including salt and glucose the kidneys filter from the blood every 24 hours - are especially vulnerable to apoptosis and injury, Dr. Dong says.

"They are highly energy-dependent," he says. "That is why when you shut off the blood supply, these cells are quickly, irreversibly damaged and they die." Tubular cell injury and death is why kidneys are so vulnerable, for example in critically ill patients.

It's in this oxygen-deprived environment that two proteins, Bid and Bax - each a known killer in its own right - are activated and may partner to induce cell death. The killing proteins are pervasive, especially in the kidneys, says Dr. Dong, who recently received a $1 million grant from the National Institute of Diabetes & Digestive & Kidney Diseases, to better understand their role in cell death during ischemic renal failure.........

Posted by: Mark      Permalink         Source

April 20, 2006, 9:12 PM CT

Shock Wave Therapy For Kidney Stones May Increase Risk Of Diabetes

Mayo Clinic scientists are sounding an alert about side effects of shock wave lithotripsy: in a research study, they found this common therapy for kidney stones to significantly increase the risk for diabetes and high blood pressure during the later part of life. Risk for diabetes was correlation to the intensity of the therapy and quantity of the shock waves administered; high blood pressure was correlation to therapy of stones in both kidneys.

Shock wave lithotripsy uses shock waves to break up an impassable kidney stone into smaller, sandlike pieces which can be passed spontaneously, commonly within a month. The patient and the lithotriptor that emits the shock waves are placed in a water bath. Water allows easier conduction of the shock waves through the patient's tissue and precise focus on the kidney stone.

"This is a completely new finding," says Amy Krambeck, M.D., Mayo Clinic urology resident and lead study investigator. "This opens the eyes of the world of urology to the fact that high blood pressure and diabetes are potential side effects. We can't say with 100 percent certainty that the shock wave therapy for the kidney stones caused diabetes and hypertension, but the association was very strong. The risk of developing diabetes after shock wave lithotripsy is almost four times the risk of people with kidney stones treated with medicine, and the risk of developing high blood pressure is one and one-half times, which is a significant risk increase."........

Posted by: JoAnn      Permalink         Source

April 20, 2006, 9:05 PM CT

Laser Therapy For Melanoma Of The Eye

Mayo Clinic scientists report that transpupillary thermotherapy (TTT) appears to be a successful therapy for most patients who have small choroidal melanomas -- a primary cancer of the eye. The results of the study are in the recent issue of Archives of Ophthalmology.

In TTT, a wide laser beam is directed at the choroidal tumor through a contact lens, causing tumor cell death. In 1996, Mayo became one of the first centers in the nation to use TTT. Three years later, Mayo scientists published the results of TTT for the first 20 patients seen (available online at http://archopht.ama-assn.org/cgi/content/full/117/11/1512).

"We wanted to reaffirm the effectiveness of TTT for our original patients by examining their follow-up data," said Colin McCannel, M.D., Mayo Clinic ophthalmologist and study co-investigator. "In addition, we hoped to show continued success with the procedure as a stand-alone therapy for choroidal melanoma."

The choroid is the vascular layer of the eye between the retina and the sclera. It is responsible for limiting reflection of light within the eye as well as providing blood supply and oxygen to the retina. Choroidal melanoma can cause vision loss and eventually spread to other parts of the body. While cancers of the eye are not very common, they historically were treated by removal of the eye to prevent spread of the cancer. There are limited therapy options beyond removing the eye, but the Mayo team showed that at least for small tumors, TTT is a very good option.........

Posted by: Janet      Permalink         Source

April 20, 2006, 8:59 PM CT

Inducing Melanoma for Cancer Vaccine

Cancer vaccines are being investigated in early-phase clinical trials around the world, with a number of of those trials recruiting patients with melanoma. Eventhough tumor regressions have been seen in 10% to 20% of patients with metastatic melanoma, the great promise of cancer vaccines - controlling tumor growth and cancer spread without serious side-effects - remains as yet unrealized. This could be set to change with the publication of a new mouse model technology in Cancer Research, the journal of the American Association of Cancer Research, from a multi-national team led by researchers at the Brussels Branch of the international Ludwig Institute for Cancer Research (LICR).

"Melanoma has been a focus of cancer vaccine development because a number of melanoma-specific vaccine targets, so-called 'cancer antigens', have been defined," says the study's senior author, LICR's Dr. Benoit Van den Eynde. "However, we have a limited understanding of how most, but not all, melanomas evade an immune system that has been primed to detect and destroy cancer cells carrying one of these defined cancer antigens".

As per Dr. Van den Eynde, this is due in part to the lack of appropriate animal models in which detailed immunological analyses can be performed before and after vaccination. "The models we use to investigate cancer vaccines at the preclinical level either have a defined cancer antigen in a transplanted tumor, or they have an 'original' tumor that doesn't have a defined antigen. However, in human clinical studies, we have original tumors with defined antigens. So there has been a need for a mouse model that more closely follows the human model."........

Posted by: Janet      Permalink         Source

April 20, 2006, 8:57 PM CT

Diabetes and Cancer: Alpha Connection

A study published by Nature today has defined the function of p110 alpha, the flag-ship molecule of the eight member PI3K family, which is one of the most frequently activated pathways in cancer. The function of p110 alpha in the body has eluded scientists for over a decade but a new approach to generating mouse models, has allowed researchers from the Ludwig Institute for Cancer Research's (LICR) UCL Branch and the UCL Centre for Diabetes & Endocrinology to solve the mystery and yield important information for planned clinical trials with PI3K inhibitors.

The study showed that p110 alpha controls the action of insulin and other key hormonal signals that play roles in growth, diabetes and obesity. p110 alpha is frequently mutated or overexpressed in cancer, and the results of the present work imply that cancer cells hijack a key signalling pathway to fuel their energy needs and drive their proliferation and survival. The current work has far-reaching implications, given that several million of people are affected by metabolic disorders, and every year, several hundreds of thousand new cancer cases with mutations in p110 alpha are diagnosed.

Importantly, says LICR's Dr. Bart Vanhaesebroeck, the senior author of the study, the findings have immediate implications for the testing of p110 alpha-specific inhibitors for human therapies. "Accurate information on the specific role of p110 alpha is needed urgently by the pharmaceutical industry, which is preparing to initiate clinical trials based on PI3K inhibition, not only in cancer but also in inflammation, allergy and auto-immunity. These mice mimic the effect of systemic administration with a p110 alpha-specific drug,".........

Posted by: JoAnn      Permalink         Source

April 20, 2006, 8:52 PM CT

Lowering Cholesterol Early In Life

New research from UT Southwestern Medical Center indicates that lowering "bad" blood cholesterol earlier in life, even by a modest amount, confers substantial protection from coronary heart disease.

The new findings, appearing in the March 23 issue of The New England Journal of Medicine, found that people with genetic variations affording them lower low-density lipoprotein (LDL) cholesterol in their blood from birth were significantly less likely to develop coronary heart disease during the later part of life than those without the variations. These variations exist in a recently discovered gene called PCSK9.

Based on 15 years of data tracking more than 12,000 multiethnic subjects ranging in age from 45 to 64, the scientists found that people who had cholesterol-lowering genetic variations that lowered their LDL level by about 40 milligrams per deciliter were eight times less likely to develop coronary heart disease than those without the mutations. Those with genetic profiles lowering their LDL by about 20 mg/dl from average had a twofold reduction in heart disease.

"These data indicate that a moderate, life-long reduction in LDL cholesterol is associated with substantial reduction in the incidence of coronary events, even in populations with a high prevalence of other cardiovascular risk factors," said Dr. Helen Hobbs, the study's senior author, director of the Eugene McDermott Center for Human Growth and Development and an investigator in the Howard Hughes Medical Institute at UT Southwestern. She also directs the Donald W. Reynolds Cardiovascular Clinical Research Center at UT Southwestern. Dr. Hobbs coauthored the study with Dr. Jonathan Cohen, professor of internal medicine and scientists from the UT Health Science Center in Houston and the University of Mississippi Medical Center in Jackson.........

Posted by: Daniel      Permalink         Source

April 20, 2006, 8:45 PM CT

Black Lean Women Face Dangers From Hormone Replacement

Increased risk of breast cancer associated with hormone replacement treatment is well known and has been discussed in this column before. Now a new study has shown that Black women have an increased risk of development of breast cancer when they take replacement hormones compared to Caucasian women. The research also found that, and that the risk is greater for leaner women.

Most of the prior studies that have linked increased breast cancer risk to the use of hormone replacement treatment were done on Caucasian women, hence this information regarding Black women was not available. The chief investigator, Dr. Lynn Rosenberg of Boston University and his colleagues investigated the association between breast cancer and hormone treatment using data from the Black Women's Health Study.

In this study data from 32,559 women 40 years of age or older was used. Scientists have shown that among these women 615 have developed breast cancer.

Rosenberg and his colleagues found that use of hormone replacement for 10 or more years is associated with a 58 percent increased risk of development of breast cancer. Interestingly they found that women lean body with history of hormone replacement of 10 years or more had three times the risk of breast cancer.

Scientists suggest that heavier women may be producing more estrogen from fat tissue and may be less affected by taking estrogens than leaner women.........

Posted by: Sherin      Permalink         Source

April 20, 2006, 8:41 PM CT

Clues To Eating Disorders

In research that may have implications for studying eating disorders in humans, a worm the size of a pinhead is helping scientists at UT Southwestern Medical Center unravel the mechanisms of hunger.

The scientists have found a series of biochemical reactions that control how the simple worm feeds, opening the way for further research into the complicated nature of hunger. Central to the research is a worm called Caenorhabditis elegans, which eats bacteria by contracting and relaxing a large muscle called the pharynx to suck in its prey. When it can't find food, C. elegans reacts by pumping the pharynx harder.

"Despite the prevalence of eating disorders from obesity to anorexia, the identity and mechanism of action of starvation signals are largely unknown," the scientists wrote in the paper, which will appear in the recent issue of Cell Metabolism.

The study of the signaling pathways in feeding muscles suggests that feeding disorders may result from inappropriate behavioral responses to starvation signals, they wrote.

"Instead of being vague about what hunger is, we can be specific, at least in these cells in these particular animals," said Dr. Leon Avery, professor of molecular biology and senior author of the study. "There's been a lot of work on hunger and behavior, but hunger has not been well-defined at the molecular level".........

Posted by: JoAnn      Permalink         Source