What's Hot
What's Hot
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| July 2000
Fewer mastectomies needed The July 19 issue of The Journal of the National Cancer Institute published the longterm results of a randomized multicenter trial in which 868 women with breast cancer were given either breast conserving therapy (BCT) or a modified radical mastectomy. Breast conserving therapy consisted of a lumpectomy with removal of a margin of one centimeter around the tumor and radiation. The trial was conducted between 1980 and 1986 and the patients were followed up for a median of 13.4 years. Eighty percent of the women in the study had tumors measuring between 2.1 and 5 centimeters. At the present, only women with tumors 2 centimeters or smaller are routinely given breast conserving therapy, while women with larger tumors are advised to undergo mastectomy. Prior research has demonstrated BCT to be as effective as mastectomy in women with these smaller tumors. After ten years, survival was 65% in those who received BCT and 66% in those receiving the mastectomy, considered to be statistically the same. Women who retained their breasts had a somewhat higher rate of recurrence, but this still had no effect on their survival rate. The two groups also experienced approximately the same rate of metastasis, with 66% of those undergoing a mastectomy remaining free of metastasis in distant locations as compared to 61% of those who received breast conserving therapy. According to BBC news, the majority of women in developing countries are diagnosed with breast cancer before the tumor reaches 5 centimeters in size. "Breast conserving therapy instead of mastectomy can therefore now be offered to the large majority of breast cancer population, said research team leader Dr Harry Bartelink of the Netherlands Cancer Institute. —D Dye
Human virus causes obesity in lab animals The August issue of the International Journal of Obesity published a study in which mice and three groups of chickens injected with a human adenovirus experienced increased gains in body fat. The University of Wisconsin scientists also innoculated another group of chickens with a different, avian adenovirus to ascertain if the fat gain could be in response to viral infection in general, but found that this group did not experience the increase in adipose tissue of those injected with the human virus. The human virus did not damage the hypothalamus, the gland which controls energy expenditure, nor did the animals eat more. Interestingly, the infected animals experienced lower levels of triglycerides and cholesterol. Experiments such as this have previously been conducted on animals, using animal viruses. This is the first study utilizing a human virus to cause obesity in animals, which leads researchers to believe that some human obesity may have a viral cause. In a prior study that included fifty-two obese people, lead study author Dr Nikhil V Dhurandhar found that only the ten most obese subjects showed antibodies to a chicken adenovirus, SMAM-1. —D Dye
Two studies find gene defect in primary pulmonary hypertension What's Hot readers may recall news of an effective treatment for pulmonary hypertension posted on May 31. Now two separate research teams, both funded by the National Heart, Lung, and Blood Institute (NHLBI) have discovered that defects in the BMPR2 gene are responsible for primary pulmonary hypertension (PPH), a rare disease of the lung in which uncontrolled growth of cells in the lungs' blood vessels leads to blockages which force the heart to pump harder and increases pulmonary artery blood pressure. The PMPR2 gene controls growth and development of the lung. Although primary pulmonary hypertension can occur at any age, including infancy, it mainly effects women in their reproductive years, with twice as many women as men diagnosed with the disease. Patients with the disease have a limited life expectancy; treatment options for advanced PPH being lung transplantation and continuous intravenous prostacyclin to relax blood vessels, both fraught with difficulty. The studies will be published in the September issues of the journals Nature Genetics and American Journal of Human Genetics. "This research is the culmination of nearly 20 years of work to identify possible immunologic and genetic factors in the cause and progression of PPH. Now that we have pinpointed a gene, we can focus on learning how it works. That information should enable us to devise better treatments and perhaps eventually a preventive therapy or cure," stated NHLBI Director Dr. Claude Lenfant. Both groups of researchers agree that BMPR2 defects are not the only cause of the disease. There are many individuals who contract the disease who do not have a family history of PPH, which leads researchers to believe that other factors are involved. The researchers next wish to find out if the same genetic defect exists in these individuals. —D Dye
Spherons linked to Alzheimer's The latest issue of Alzheimer's Reports featured an article in which Spherons, tiny balls of tightly packed protein found in some brain cells throughout human brains, have been linked with Alzheimer's disease. Using forensic techniques to date amyloid beta proteins found in the Spherons, researchers from Nymox Corporation found them be quite old, some as old as eighty years. Other than proteins in teeth and bones, most proteins in the body last no longer than a few weeks. Previous research by other scientists found that senile plaques, the brain lesions found in Alzheimer's disease, also contained similarly aged amyloid beta proteins. Senile plaques and Spherons have been the only sites in the brain in which this aged protein is found. The scientists concluded that as humans age, the Spherons grow until they become too large for the cell that contains them, which causes them to be released. The Spherons then burst, causing senile plaques. —D Dye
Most cancer not inherited A study of 44,788 pairs of Scandinavian twins just published in the New England Journal of Medicine revealed that while more cancers are hereditary than previously thought, they still comprise a minority of cancers. The study examined twins because they share the same genetics. Researchers were able to observe whether cancer appeared in one or both twins. In identical twins, the average of cancer appearing in both twins was generally less than 15%, clearly a low rate. Cancers with the strongest hereditary component were prostate, colorectal and breast cancer, however genetics still accounted for the minority of these cases. Prostate cancer appeared to be the type of cancer that was associated with the greatest (42%) inherited risk. —D Dye
Water breaks up blood clots Six locations in the US will be the sites of a multicenter research study that utilizes pressurized saline (salt water) at a speed of 300 miles per hour to break up blood clots in the brain. The technique involves the use of a device called the Angiojet Rheolytic Thrombectomy System made by Possis Medical, Incorporated, which is threaded from a leg artery to the site of the bloodclot in the brain. The Angiojet is then used to deliver the saline which breaks up the clot and removes the residue. Patients are initially given a CT scan to determine that their stroke is not of the hemmorhagic variety, resulting from bleeding within the brain, and are followed up with an angiogram to ascertain that the clot has been dissolved. In some cases patients are additionally given TPA, a clot-dissolving drug. Principal study investigator Lawrence Wechsler, MD, of the University of Pittsburgh School of Medicine stated, "The goal of the use of this experimental device is to open the blood vessel and quickly restore blood flow to the region of the stroke and restore function. It may be possible to remove the blood clot within minutes instead of the 30 to 90 minutes needed for infusion of the clot-busting drug TPA. The faster we can restore blood supply to the affected area of the brain, the less damage the stroke will cause . . . We can use this experimental treatment up to six hours after the patient has a stroke compared to intravenous TPA treatment, which only has a three-hour window of opportunity" Although the Angiojet is currently has not yet been approved by the FDA for strokes, it is currently approved for use in removing clots in coronary and leg arteries, and dialysis access grafts. —D Dye
Drug shows promise in Alzheimer's disease The World Alzheimer's Congress 2000 held in Washington DC this week was the site of the announcement by NeoTherapeutics Corporation and scientists from Indiana University that the drug Neotrofin tm improved memory in Alzheimer's patients and reduced the level of beta amyloid in cell cultures. Beta amyloid is a protein found in increasing amounts in the brains of Alzheimer's patients which results in the formation of plaques that lead to the death of brain cells. Neotrofin tm effects the processing of the amyloid precursor protein, for which there is altered processing in the disease. It also stimulates the production of neurotrophic (nerve growth) factors necessary for nerve regeneration. —D Dye
Antibodies aid remyelination In what has been called a major scientific discovery, researchers at the Mayo Clinic have stimulated the regrowth of damaged myelin in mice through the use of two human antibodies. Mice given a virus that causes multiple sclerosis symptoms were injected with two human monoclonal antibodies, and were pathologically examined five weeks later. Remyelination occurred in an amount equal to or great than the current treatment of human intravenous immunoglobulin. Mice given one antibody showed remyelination of one quarter of their damaged tissue. —D Dye
Tumor reversion studied The start up company, Molecular Engines Laboratories is seeking to develop new cancer therapies by studying a phenomenon called tumor reversion. Tumor reversion rests on an observation made by Adam Telerman and Robert Amson ten years ago that a tumor cell can be reprogrammed into a noncancerous state. Telerman and Amson joined genomics researcher Daniel Cohen and Nobel laureate Jean Dausset of the Human Polymorphism Study Center, who collaberated with another Nobel laureate, physicist Georges Charpak, and Claude Hennion, formerly the president of Biospace Instruments. Certain members of the group founded the new company based on encouraging results in their research. —D Dye
Cardiac bypass given under local anesthetic For the first time in the US, an a coronary bypass operation was given to a patient who received a local anesthetic. On June 15, a team of surgeons at the VA Pittsburgh Healthcare System working with surgeons from the University of Pittsburgh Medical Center operated on a fifty-one year old patient who received an epidural anesthetic which numbed his chest area. The patient was fully awake and was able to speak to the staff during the procedure. —D Dye
Resveratrol fights cancer, heart disease Researchers at the University of North Carolina, Chapel Hill have discovered the reason why trans-resveratrol, a substance found in grapes, is effective against cancer and heart disease. The findings help to explain the protective benefit exerted by regular wine consumption observed in some studies. Resveratrol (or Res) was found to turn off a mechanism involving a protein that attaches to DNA inside the cell, NF-kappa B, which prevents cancer cells from being killed. The study was published in this month's issue of Cancer Research. —D Dye
Cancer cells killed by virus A team of Canadian scientists have discovered that vesicular stomatitis virus, or VSV, is able to kill cancer in some tumor cells. The theory that infection by a virus may have an adverse effect on cancer has piqued the curiosity of researchers for some time. In this study, published in the July 2000 issue of the journal Nature Medicine, researchers acted on the knowledge that interferon has had limited results in inhibiting the growth of cancerous tumors because of mutations specific to cancer in the genes involved in the interferon pathway. Interferon is a substance produced by cells infected with a virus, that inhibits viral growth. It is effective against many different viruses, and has the ability to induce growth inhibiting signals in normal and tumor cells. Cancer cells that do not respond to interferon have developed a survival advantage, and the hypothesis in this study is that this may have also compromised their own antiviral response, rendering them vulnerable to viral infection. The researchers infected with VSV several normal cell lines and tumor cell lines grafted into mice. VSV is known to be sensitive to treatment by interferon. The tumor cell lines used in the experiment included ovary, lung, prostate and colon cancer, and melanoma. The cell lines were each subdivided into two groups, one which was pretreated with interferon and the other left untreated. The tumor cells produced much higher viral counts the following day than did the normal cells, and experienced more rapid cell death. The virus killed all of the melanoma cells within twenty-four hours, pretreatment with interferon not having a protective effect. Some tumor lines showed a limited response to interferon after pretreatment, demonstrating that their interferon response was functional, but impaired. Normal prostate and ovarian tissue infected with VSV began to display signs of cell death after thirty-six hours, but those pretreated with interferon were indistinguishable from uninfected cells seventy-two hours after infection. —D Dye
Vitamin C status correlates with male mortality The July 2000 issue of the American Journal of Clinical Nutrition reported the results of a study in which 7071 adults, aged thirty to seventy-five, were tested for serum vitamin C as part of the National Health and Nutrition Examination survey conducted between 1976 and 1980. The status of the participants was examined in 1992. Men who had the lowest serum vitamin C experienced a 57% greater risk of dying from any cause and a 62% greater risk of dying from cancer than did men who had the highest serum ascorbate levels. This correlation was not observed in women. These statistics were the same when when analyses were limited to nonsmokers or further to adults who never smoked. Vitamin C is believed to protect against cancer by detoxifying carcinogens and enhancing immune function. It protects against the number one cause of death, heart disease, though its role in collagen and prostacyclin production as well as by its antioxidant ability. According to the study, women tend to have higher serum ascorbate levels. Since the increased risk of mortality was observed in men whose serum ascorbate levels fell within the lowest grouping, this may explain why the lowest grouping of women did not experience the same risk. Vitamin C also appears to be more protective against nonhormone-dependent cancers which occur more frequently in men, and may explain why men with higher levels of vitamin C experienced fewer deaths from cancer. —D Dye
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