ScienceBlog.com

A new clinical trial hopes to unravel the genetic and molecular basis for delirium, a common complication afflicting elderly patients after major surgery. Delirium, which can prolong the recovery of elderly surgical patients, is a mental state characterized by impaired cognitive function, fluctuating levels of consciousness, disturbed sleep-wake cycles and agitation. Although difficult to measure, the incidence of delirium has been reported to be as high as 60 percent, with the elderly at the highest risk, the researchers said.

In studies using rats, researchers from Duke University Medical Center and the Imperial College, London, have found evidence that the chemically inert gas xenon can protect the brain from the neurological damage often associated with the use of the heart-lung machine during coronary artery bypass surgery. The researchers say that xenon appears to block receptors on nerve cells in the brain that can be “overstimulated” in response to the surgery. This overstimulation can lead to nerve cell damage or death.

Researchers have developed a new statistical genetic “fishing net” that they have cast into a sea of complex genetic data on autistic children to harvest an elusive autism gene.
Moreover, the researchers said that the success of the approach will be broadly applicable to studying genetic risk factors for other complex genetic diseases, such as hypertension, diabetes and multiple sclerosis. In this case, the gene, which encodes part of a brain neurotransmitter docking station called the gamma-Aminobutyric Acid Receptor beta3-subunit (GABRB3), has been implicated in autism previously, but never positively linked to the disease. Their findings will be published in the March 2003 issue of the American Journal of Human Genetics.

An international team of researchers has demonstrated a genetic basis for a fatal form of inherited cardiac arrhythmia that usually strikes young, seemingly healthy people. Basing their research on a French family with a form (Type 4) of inherited Long QT Syndrome (LQTS) and experiments in mice, the researchers found the mutation in a specific gene encoding ankyrin-B, a protein within heart muscle cells. Their discovery identifies what appears to be a novel mechanism for cardiac arrhythmia.

In their ongoing research on turning adult stem cells isolated from fat into cartilage, researchers have demonstrated that the level of oxygen present during the transformation process is a key switch in stimulating the stem cells to change. Using a biochemical cocktail of steroids and growth factors, the researchers have “retrained” specific adult stem cells that would normally form the structure of fat into another type of cell known as a chondrocyte, or cartilage cell. During this process, if the cells were grown in the presence of “room air,” which is about 20 percent oxygen, the stem cells tended to proliferate; however, if the level of oxygen was reduced to 5 percent, the stem cells transformed into chondrocytes.

Researchers have shown that removing a portion, instead of all, of the spleen, can successfully treat children with a variety of congenital anemias while preserving important splenic immune function. In the largest study of its kind in the U.S., the researchers performed the surgery, known as a partial splenectomy, on 25 children with congenital forms of anemia caused by abnormal red blood cells. Typically, these children suffer from fatigue, jaundice and extreme vulnerability to infections that can require repeated hospital or physician visits. Many also need repeated blood transfusions.

Doctors have found that a positive-pressure method commonly used to treat obstructive sleep apnea (OSA) also alleviates symptoms of nocturnal gastroesophageal reflux (nGER) in many patients suffering from both disorders. The results of their study are published in the Jan. 13, 2002, issue of the Archives of Internal Medicine. The researchers believe that the treatment, called continuous positive airway pressure (CPAP) likely alleviates nGER by preventing acid from regurgitating from the stomach.

A combination of chemicals given to protect Gulf War soldiers against deadly diseases and nerve gas may have inadvertently damaged their testes and sperm production, according to animal experiments at Duke University Medical Center. The new study could explain why some veterans have experienced infertility, sexual dysfunction, and other genitourinary symptoms, said Mohamed Abou Donia, Ph.D., a Duke pharmacologist.

By taking continuous electrocardiogram (ECG) readings for 24 hours after treating heart attack patients, researches have shown that giving a combination of a new drug that prevents platelets from clumping together, as well as a clot-busting drug, opens up clogged arteries faster and keeps them open longer.

Researchers have shown that an age-related loss of specific stem cells that continually repair damage to blood vessels is critical to determining the onset and progression of atherosclerosis. Stem cells are immature cells that have the potential to mature into a variety of different cells. This novel view of the disease, based on experiments in mice, constitutes a potential new avenue in the treatment of one of the leading causes of death and illness in the U.S., the researchers said.

Despite recent reports that hormone therapy does not offer protection for post-menopausal females against heart disease and heart attack, researchers from Duke University Medical Center have determined in mouse studies that non-hormone treated pre-menopausal females are, in fact, better protected from cardiac damage following ischemia compared to their male counterparts. The findings suggest that research should continue toward finding better ways to treat post-menopausal women to maintain such cardiac protection, the researchers said.

A diet rich in flaxseed seems to reduce the size, aggressiveness and severity of tumors in mice that have been genetically engineered to develop prostate cancer, according to new research from Duke University Medical Center. And in 3 percent of the mice, the flaxseed diet kept them from getting the disease at all. “The amount of flaxseed given to each mouse was 5 percent of its total food intake, which would be a very difficult amount for humans to eat,” said a lead researcher. “[B]ut it does signal that we are on the right track and need to continue research in this area.”

Irritable Bowel Syndrome, or IBS, is a common condition, and a costly one. The gastrointestinal disorder accounts for 12 percent of primary care visits and costs our health care system $8 billion annually. Now a pilot study has found that paroxetine, a drug in the most common class of antidepressants, is effective and safe for treating IBS symptoms.

An international team of scientists has discovered a novel genetic trait that protects its carriers against the deadliest forms of malaria, while people without the trait are more likely to succumb to its fatal consequences. This trait — a mutation or “polymorphism” in the NOS2 gene — controls the production of nitric oxide, a small chemical that can kill parasites and prevent malaria disease.

For the first time, researchers have demonstrated that exercise — without accompanying weight loss — has a positive impact on improving cholesterol levels. Further, they report that it is the amount of activity, and not necessarily any changes in fitness or intensity of exercise, that is important for cholesterol improvement. In the process of their studies, the researchers also demonstrated that the standard lipid panels used by doctors to measure the so-called “bad” LDL and “good” HDL forms of cholesterol do not necessarily provide the most accurate information in determining one’s risk of developing heart disease.

Many low birth-weight babies face serious health problems, but there are also risks of injury during delivery for large infants — and their moms. A new study confirms that a mathematical equation using standard health data obtained from every woman during pregnancy can predict birth weight within eight percent of actual birth weight, which is just as accurate as ultrasound.

Researchers have discovered that an important cellular “off-switch” that desensitizes receptors on the cell surface also regulates a second deactivation mechanism that had not been suspected before. Their finding that the off-switch, known as beta-arrestin, operates in two distinct ways may hint at a broader set of regulatory roles for the molecule.

A seemingly mild “insult” to the brain could sensitize neurons to attack by immune system proteins that are otherwise protective, researchers have found. The finding could explain why sufferers of Alzheimer’s and other neurodegenerative diseases significantly worsen following such insults. The scientists believe that drugs to selectively inhibit the immune proteins could reduce the rate of neural damage in a wide range of neurodegenerative diseases. Such drugs could also protect other organs against damage from autoimmune diseases such as lupus and rheumatoid arthritis, in which the immune system attacks body tissues.