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Thursday, December 06, 2007

More Science News

More tidbits from Science News Vol 169...

ovarian cancer Delivering chemotherapy directly into the abdomen improves survival rate, according to a new study. The study, carried out on 415 women with ovarian cancer that was spreading to nearby tissues, resulted in some of the women receiving the standard intravenous chemotherapy or standard therapy plus 6 courses, at three-week intervals, of chemotherapy injected into the abdomen via catheter. According to the article, the women getting the abdominal infusions in addition to regular chemotherapy had a median survival rate of 66 months, as opposed to 50 months for women on chemotherapy alone. Of course, the abdominal therapy caused more gastrointestinal, nerve, and heart problems, and complications and discomfort associated with the catheters. And, after 1 year, surviving patients in both groups reported similar quality of life. I'm not sure I'd want to go through all that just for the additional what, 16 months of time? If you knew you had stage III ovarian cancer would you want such aggressive treatment (knowing that ovarian cancer is very aggressive), or would you just say buggrit?

Lupus patients who no longer respond to medication can have their immune system rebuilt using their own stem cells, according to a Richard K. Burt, a physician and immunologist at Northwestern University School of Medicine in Chicago. Lupus is an autoimmune disease in which white blood cells create antibodies that damage cells and tissues, resulting in rashes, swollen joints, fever, and fatigue, and sometimes vital organs such as the kidneys, lungs, and nervous systems. While immune-suppressive drugs can alleviate the symptoms, they also can have debilitating side effects, and eventually stop working. However, if doctors administer a drug that coaxes stem cells out of a patient's bone marrow into the bloodstream, they can isolate the stem cells, then wipe out remaining white blood cells. While this leaves the patient without an immune system temporarily, doctors return the isolated stem cells to the patient's bloodstream. Such stem cells then grow into working immune cells, forming white blood cells that are less likely to make rogue antibodies. No patient has died as a result of this therapy, which is pretty impressive when you consider that the patients treated had life-threatening symptoms or impending organ damage, and were not expected to improve.

mad cow diseasePrion proteins that, when malformed, cause neurodegenerative disorders like mad cow disease, when normal, maintain the body's cache of blood-producing stem cells, according to Susan Lindquist of the Whitehead Institute for Biomedical Research in Cambridge, Mass., and her colleague Zhang Cheng Cheng. Together with colleagues Andrew Steele and Harvey Lodish, the scientists conducted experiments that showed that when they subjected stem cells to the stress of bone marrow transplants after killing off existing blood-producing stem cells, new stem cells without PrP (prion protein) gradually lost their ability to reconstitute themselves following each successive transplant. However, when the scientists inserted the gene for PrP into stem cells taken from mice lacking PrP, the new cells proved to be just as hardy as normal stem cells. Lodish states that blood-producing stem cells "spring into action ... when there is a loss of blood, a massive infection, or a bone marrow transplant." However, Andrea LeBlanc of McGill University in Montreal, who investigates these proteins, pointed out that the experiments don't explain why mice without the PrP gene can survive to old age, given that blood-producing stem cells wear out over a lifetime of normal stress.

ricin vaccine A vaccine against ricin, a toxin derived from castor seeds, appears to be safe and generates antibodies that confer immunity without killing cells, according to Ellen S. Vitetta of the University of Texas Southwestern Medical Center in Dallas. However, such antibodies are protective only if they are present before a person is exposed to ricin. Vitetta and her colleagues developed the vaccine, RiVax, by modifying the plant gene that makes part of the toxin. The vaccine produced side effects that were mild and temporary.

save the vultures Gerry Swan of the University of Pretoria in South Africa, and his colleagues, have found that meloxicam, an NSAID (non-steroidal anti-inflammatory drug) that can be used to treat swelling and pain in cattle and water buffalo, does not harm several species of Gyps vultures, unlike the NSAID diclofenac, which killed vultures. Species counts of Gyps vultures such as the oriental white-backed vulture (Gyps bengalensis), the long-billed vulture (Gyps indicus), and the slender-billed vulture (Gyps tenuirostris) dropped by more than 95 per cent since the early 1990s. The decline of vulture populations caused an increase in the population of feral dogs according to Rhys Green of the Royal Society for the Protection of Birds in Bedfordshire, England. Several NSAIDs have been shown to affect blood flow to the kidneys, causing kidney damage in birds. However, meloxicam is more expensive than diclofenac. Green points out that the patent on meloxicam has expired and hopefully, companies will be able to manufacture and sell it for lower prices soon, saving the lives of these important and necessary carrion-eaters.

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