What's Hot
What's Hot
 |
| December 2000
Ribavirin works by mutating hepatitis C virus Ribavirin is one of the few drugs found to be effective for many hepatitis C patients. The Life Extension Foundation had recommended ribavirin for this difficult to treat disease years before it was approved in the United States for this purpose. In an article published in December's Nature Medicine, researchers at the University of California, San Francisco have discovered that ribavirin works by generating so many mutations to the virus that the virus is overwhelmed by them, which is known as error catastrophe. According to the researchers, this new discovery will help drug companies create more effective versions of ribavirin. It was previously believed that ribavirin worked by blocking an enzyme used when the virus copied its genome, but this was questioned because more potent inhibitors of the enzyme were not effective against the viruses treated by ribavirin. In this experiment, researchers added ribavirin to a virus in vitro and observed a correlation between the drug's antiviral ability and its mutagenic activity. At the highest ribavirin concentrations used in the study, only one of ten million virus particles were not killed by mutations. —D Dye
Prostate cancer slowed by immunotherapy Researchers at the University of California, San Francisco have discovered that a new therapy that enables the immune system to kill prostate cancer cells can lower PSA and slow the progression of the disease. The study, published in the December issue of the Journal of Clinical Oncology, involved the collection of important immune system cells known as dendritic cells from the blood thirty-one men with hormone-refractory advanced prostate cancer. These cells scavenge foreign material and bring it to the attention of the lymphocytes, a type of white blood cell, which then destroy it. In this study, dendritic cells were combined with synthetic prostatic acid phosphatase, or PAP, an antigen that exists on the surface of most prostate cancer cells, and infused back into the patients once per month for three months in the hope it would train the patients' lymphocytes to recognize cells with PAPon them as a foreign substance. —D Dye
Intravenous oxygen carrier lessens transfusion need The 54th Postgraduate Assembly in Anesthesiology held in New York this week was the site of an announcement by Professor Donat R Spahn MD, of the Institute of Anesthesiology, University Hospital, Zurich Switzerland, that administration of Oxygent™ to patients who experienced blood loss during surgery caused either a complete avoidance of transfusion or the need for fewer units of blood than a control group. One of the functions of blood is the transportation of oxygen throughout the body. Oxygent, made by Alliance Pharmaceutical Corporation from a synthetic perfluorochemical compound, acts as an intravenous oxygen carrier when administered to people who have experienced blood loss. This is important in light of the existing nationwide blood shortage. The international Phase 3 general surgery study enrolled 492 patients who underwent orthopedic, urologic, abdominal, vascular, and other major surgical procedures, many due to malignant disease, in which 424 lost anywhere from 10 to 80 milliliters blood per kilogram body weight. In the 424 patients who experienced this level of blood loss, those who received Oxygent either avoided the need for a blood transfusion or needed less blood. This statistic was observed throughout the study period following the patients' surgeries. —D Dye
Proinsulin levels predictive of stroke Proinsulin levels are frequently high in type 2 diabetics, and have been linked to the increased level of cardiovascular disease seen in this population, even more so than insulin. The pancreas of diabetics may increase proinsulin production in response to the increased insulin resistance experienced by diabetics. The December issue of Stroke: Journal of the American Heart Association reported a study of nondiabetics who had experienced a first stroke, in which proinsulin and insulin levels were measured. The incident case-referent study involved fifty-nine men and thirty-five women who had experienced their first stroke and one hundred seventy-eight controls matched for age and sex. Blood samples were collected before the strokes occured and insulin and proinsulin measured. The study adjusted for total cholesterol, systolic blood pressure, smoking, body mass index, and insulin. —D Dye
New treatment for diabetic macular edema Diabetes is the leading cause of blindness between the ages of twenty and seventy-four. Diabetic macular edema, or DME occurs when the retinal blood vessels of diabetic patients deteriorate, causing leakage. Of the nations 10.3 million diabetics, half a million have DME. Forty percent of all diabetics develop DME with 75,000 new cases diagnosed each year. —D Dye
Liver dialysis aids damaged liver A liver dialysis machine that has been used by twenty-three hospitals so far in the United States was used for the first time in this country to support liver functions in a patient with trauma to the liver at University Medical Center, University of Arizona. The dialysis unit is being used on a gunshot wound victim with injury to over 70% of the liver. University Medical Center physicians decided to use the dialysis machine on the patient to help clear toxins from the bloodstream to relieve the liver of some of its stress and enable it to regenerate. Steven B. Johnson, M.D., associate professor of surgery in the Section of Trauma and chief of Surgical Critical Care at the University of Arizona College of Medicine, stated "The liver dialysis unit basically is taking over many of the functions of the liver so that the patient can heal . . . Having the technology to provide liver dialysis gives UMC an effective tool for the treatment of patients with liver disease, drug overdoses, and with severe injuries to the liver." Liver dialysis is accomplished by the use of a compact, mobile and self-contained system. It's approximate size is that of a dishwasher and it can be wheeled into the patient's room. It works by removing toxins or external or internal origin from the blood to prevent further deterioration that can lead to multiorgan failure and ultimately death. Without coming into contact with the blood, powdered activated charcoal and other chemicals remove toxins. It is the only technology approved by the FDA to assist those suffering from liver decompensation or drug overdose. Treatment lasts from four to six hours over a period of two to five days. —D Dye
Folic acid antagonist-caused birth defects reduced by vitamins Commonly prescribed drugs that act as antagonists to the B vitamin folic acid are classified as either dihydrofolate reductase inhibitors, which includes the drugs aminopterin, methotrexate, sulfasalazine, trimethoprim, triamterene, pyrimethamine, or those that antagonize folic acid in a different manner, including antiepileptic drugs carbamazepine, phenytoin, phenobarbital, and primidone. Research has shown that folic acid deficiency is the cause of neural tube defect (spina bifida) as well as other defects such as cleft palate or cleft lip, cardiovascular defects such as patent ductus arteriosus, atrial septal defects, coarctations of the aorta, and pulmonary-valve anomalies, and several urinary tract defects. A study published in the November 30 New England Journal of Medicine sought to determine if the use of folic acid antagonists during pregnancy increased these defects in the children of the women taking them and if the use of folic acid during pregnancy might prevent some of these defects. —D Dye
Creatine protects brain from injury Creatine is a popular nutritional supplement among body builders and athletes, used to enhance endurance and muscle gain. Creatine is synthesized in the body from the amino acids arginine and glycine. It is absorbed by and stored in the major skeletal muscles and the heart. Creatine use maintains higher levels of ATP, or adenosine triphosphate, the cell's energy molecule. In research published in November's Annals of Neurology, creatine was shown to also have the ability to reduce the loss of neurons in the brain's cortex that occurs after injury. Researchers at the University of Kentucky gave creatine to mice for periods of one, three or five days before inflicting trauma that resembles human closed head injury (the closed cortical impact model). The mice who received the creatine three and five days before receiving the head injuries had 36% less damage one week later than the control mice. The researchers reported a similar experiment in which rats were given creatine four weeks prior to receiving head injuries had half the loss of neurons than the placebo group. Creatine evidently works by benefitting the mitochondria, which are the cell's energy producing power plants. The rats' brains were found to have increased mitochondrial membrane potential, and levels of calcium and damaging reactive oxygen were reduced within the mitochondria. Levels of ATP were maintained. —D Dye
|
