San Francisco
Tree rings may tell how old a tree is, but the rings or annual bands in some skeletal coral may tell not only the age of the animal, but also something of the dynamics of the ocean in which it grew, according to Penn State and University of Miami researchers. "Some coral grows like a tree; each year a complete layer with both a high and low-density skeletal calcium carbonate band is formed by the coral animal," says Dr. Lisa Greer, assistant professor of geosciences. "Not all corals create rings, but the massive corals like boulder star coral or pin cushion coral do."
Another menopausal myth is challenged: Women with existing coronary disease do not realize improvement in their cognitive function as a result of taking the most common form of hormone replacement therapy, a UCSF study has found. Investigators followed more than 1000 women from ten US test sites for four years. Half took a placebo; the other half took hormone replacement therapy (HRT). Although other, smaller studies have shown an improvement, in the UCSF study the women who received HRT performed no better on standard tests of cognitive function than those who received placebo.
No cases of HIV transmission through unprotected receptive oral sex were found by researchers at UCSF's Center for AIDS Prevention Studies in a new study. The study looked at men who have sex with men and who exclusively practice oral sex as the receptive partner. "HIV infection through receptive oral sex is a very rare event?statistically our study showed a probability of zero?and is rarer than HIV infection through receptive anal intercourse using a condom," said the study's lead author Kimberly Page Shafer, PhD, MPH, assistant professor of medicine at UCSF's CAPS. The findings are being published in the November 22, 2002 issue of AIDS.
Previously secret documents show that tobacco companies provided money, cultivated social and political ties, and aggressively offered free cigarettes to African American leadership groups ?even as the evidence grew that African Americans bear a disproportionate share of the tobacco-related disease burden, researchers at the University of California say.
A neurologist at the University of California at San Francisco says stroke in neonates and children is severely under-recognized, with about 1 case per 4,000 live births. About 6 percent of those children will die, 20 to 35 percent will go on to have another stroke, and more than two-thirds of survivors will have neurological deficits or seizures.
While cautioning that their findings still must be evaluated in humans, University of California, San Francisco and Stanford University Medical Center researchers report that the cholesterol-lowering drug atorvastatin (Lipitor) significantly improved, prevented relapses or reversed paralysis in mice with an experimental disease that closely resembles multiple sclerosis. The study, reported in the November 7 issue of Nature, was conducted in mice with experimental autoimmune encephalomyelitis (EAE), the standard animal model for multiple sclerosis.
By experimentally switching genes off or on at specific stages in an animal's lifecycle, California scientists have discovered that vigor and lifespan can be significantly extended with no side effects. Many researchers believe that increasing lifespan will dampen reproduction. But the new study of the tiny roundworm commonly known as C. elegans shows that silencing a key gene only in adulthood increases longevity with no effect on reproduction.
Researchers say they've developed a new test for prions that improves the accuracy and speed with which the malformed and infectious proteins can be detected. Prions cause neurodegenerative diseases in sheep, deer and elk, plus Mad Cow disease in cattle and Creutzfeldt-Jakob in humans.
Pre-cells destined to become fat can be converted instead into true bone cells in
response to outside signals, say researchers at the University of California, San Francisco. The finding could pave the way for scientists to replenish lost bone cells in patients with conditions like osteoporosis, and to help repair bone defects. The new bone cells have all the hallmarks associated with mature bone formation, including production of bone proteins and calcification, the UCSF team says.
From Barney W. Greinke in Berkeley:
"When people point out the great technological accomplishments of the 20th century, they usually think it's the big things that are the most important ones. The atom bomb, jet airplanes, the Salk vaccine, electronic computing, DNA, men on the moon.
"How incredibly wrong they are.
