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New Viruses Search and Destroy Cancer Cells
One of the most exciting fields in medical science today is virotherapy, which involves creating genetically modified viruses that attack cancer cells but leave normal, healthy cells alone. And the most exciting virotherapy research does not use animals.
Working on a treatment for ovarian cancer, a group of scientists from the University of Alabama and Groningen University in the Netherlands decided that the safest and most effective way to test their new virus was on human tissues.
The research team, led by David Curiel, M.D., Ph.D., modified an adenovirus specifically to target ovarian cancer cells. The team then safety-tested the therapy in vitro using normal human liver tissues and primary ovarian tumor tissues taken from biopsies at the University of Alabama hospital. Just as predicted, the modified virus infected tumor tissues but not normal liver tissues.
The virotherapy is being tested in clinical trials, and Dr. Curiel is working with the National Cancer Institute and the Food and Drug Administration to recommend this nonanimal method to other researchers across the country.
Kirby TO, et al. A novel ex vivo model system for evaluation of conditionally replicative adenoviruses therapeutic efficacy and toxicity. Clin Cancer Res. 2004;10:8697-8703.
In Vitro Models Outperform Rabit Tests
Common bacteria, such as staphylococcus, are increasingly resistant to antibiotics. The result is severe, hard-to-treat infections in vulnerable populations, including children, the elderly, and immuno-compromised persons. Although scientists are continually working on new antibiotics to help combat these infections, some are still using rabbits in the process.
However, several years ago, a research team at Michigan’s Wayne State University developed an in vitro model that accurately mirrors the distribution of bacteria and antibiotics in humans, eliminating problems of species extrapolation. The team recently published a study that uses the in vitro model to test combinations of already proven drugs; these new dose regimens hold great promise for helping human patients.
Huang V, Rybak MJ. Pharmacodynamics of cefepime alone and in combination with various antimicrobials against methicillin-resistant Staphylococcus aureus in an in vitro pharmacodynamic infection model. Antimicrob Agents Chemother. 2005; 49:302-8.
Hershberger E. et al. Comparison of a rabbit model of bacterial endocarditis and an in vitro infection model with simulated endocardial vegetations. Antimicrob Agents Chemother. 2000;44:1921-1924.
High-Dose Estrogen in Teens Linked to Infertility
The controversial use of high-dose estrogen to suppress growth in tall adolescent girls appears to affect fertility adversely in later years, according to a new report in Lancet. Researchers studied a group of 780 Australian women who had either been treated as adolescents or had declined treatment. They found the women in the treated group were more likely to have had trouble conceiving and more likely to have taken fertility drugs. Although the practice of prescribing high-dose estrogen to adolescent girls is much less common than it was two or three decades ago, PCRM president Neal Barnard published a paper in 2002 showing that one-third of U.S. pediatric endocrinologists still offer the treatment.
Venn A. et al. Oestrogen treatment to reduce the adult height of tall girls: long-term effects on fertility. Lancet. 2004; 364:1513-1518.
Barnard ND, Scialli AR, Bobela S. The current use of estrogens for growth-suppressant therapy in adolescent girls. J Ped Adol Gynecol. 2002;15:23-26.
A Healthy Weight Trumps Exercise
Exercise is great for health, but, by itself, cannot overcome the risks associated with obesity. Harvard researchers followed 10,282 nonsmoking women over a period of 24 years and found that increased overweight predicted a higher risk of death regardless of the level of physical activity. Obese women exercising 3.5 hours or more per week suffered nearly twice the risk of death compared to leaner women exercising at the same level.
Hu FB, Willett WC, Li T, et al. Adiposity as compared with physical activity in predicting mortality among women. NEJM. 2004;351:2694-2703.
High-Protein Diets Increase Heart Disease Risk
The low-carbohydrate diets that recently enjoyed fad status promoted meat consumption as a substitute for rice, potatoes, and bread. However, a recent study adds more evidence that this diet may increase the risk for coronary heart disease (CHD) and overall mortality. Investigators analyzed dietary records and health outcomes of 29,017 postmenopausal Iowan women and found that heart disease mortality was associated with increased intakes of red meat and dairy products. Conversely, replacing animal proteins in the diet with vegetable proteins, as is seen in vegetarian diets, cut the risk of CHD mortality by as much as 30 percent.
Kelemen LE, Kushi LH, Jacobs DR, et al. Associations of dietary protein with disease and mortality in a prospective study of postmenopausal women. Am J Epidemiol. 2005;161:239-249.
Diet Affects Polyarthritis
New evidence suggests nutritional factors may play a role in the development of inflammatory polyarthritis, a form of arthritis that causes pain, swelling, and stiffness in multiple joints. Using a large study population, researchers with the European Prospective Investigation of Cancer in Norfolk, England, identified 88 people with the condition and compared their eating habits with those of 176 others. They found that meat intake was higher among those with polyarthritis. In fact, those consuming the most meat products had a 130 percent increased risk for developing inflammatory polyarthritis compared to those with the lowest intake.
Pattison DJ, Symmons DP, Lunt M, et al. Dietary risk factors for the development of inflammatory polyarthritis: evidence for a role of high level of red meat consumption. Arthritis Rheum. 2004;50:3804-3812.
Meat Multiplies Diabetes Risk
AWestern-style diet, high in red and processed meats, refined grains, sweets, and high-fat dairy products, is associated with an increased risk for developing type 2 diabetes. Harvard researchers followed 69,554 nondiabetic women from the Nurses’ Health Study cohort who initially did not have diabetes, and assessed their dietary intakes. Based upon dietary pattern intakes, they were placed into either a “prudent” or “Western” diet category. Investigators found that the Western pattern significantly increased the risk for type 2 diabetes. For every serving of red meat consumed, the risk for developing type 2 diabetes increased by 26 percent. For each serving of processed meat, the risk increased by 38 percent; and for each single serving of bacon, the risk increased 73 percent.
Fung TT, Schulze M, Manson JE, et al. Dietary patterns, meat intake, and the risk of type 2 diabetes in women. Arch Intern Med. 2004; 164:2235-2240.