Bay Area Research Roundup
Aspirin may slow gene mutations
Aspirin and similar anti-inflammatory drugs may lower the risk of getting cancer by slowing the development of genetic mutations that build up in tumor cells, according to UCSF scientists.
Nonsteroidal anti-inflammatory drugs, or NSAIDs, are known to reduce death rates from several types of cancer by about 20 percent, but scientists have never understood why.
The UCSF research looked at 13 patients with a precancerous condition called Barrett's esophagus that occasionally leads to esophageal cancer. The patients were tracked for six to 19 years, and during that time had multiple biopsies taken of precancerous tissue.
The scientists found that when patients were taking daily aspirin, the rate at which the precancerous cells developed genetic mutations dropped significantly. All cells develop genetic mutations over time, but cancerous cells mutate much faster. Those genetic mutations cause both the wild growth of cancer and drug resistance.
Over the course of the study, one of the 13 patients developed cancer.
The study suggests that drugs designed to slow or stop formation of genetic mutations may be a useful goal for future cancer therapies, the scientists said. Their research was published online June 13 in the journal PLOS Genetics.
- Erin Allday
Immunosuppressant benefits elderly mice
An immunosuppressant drug already approved by the U.S. Food and Drug Administration slows down and in some cases reverses heart disease in elderly mice, according to scientists at the Buck Institute for Research and Aging.
The 2-year-old mice -- the human equivalent of 70 or 75 years -- all had age-related heart disease and were put on three-month treatments with the drug rapamycin, which is used to prevent organ rejection in human transplant patients.
After treatment, the animals showed significant improvement in several symptoms associated with heart disease. Mice that did not receive the drug continued to show declines in heart health over the three-month time period.
In previous studies, rapamycin has been shown to lengthen the lives of mice by roughly 12 percent.
The scientists said it's unclear whether rapamycin would help human hearts as well, especially since the drug causes metabolic side effects when given to transplant patients. It may be that it could offer benefits to elderly patients, however.
Results of the mouse study were published online June 4 in the journal Aging Cell.
- Erin Allday
Nitrogen dioxide puts infants at greater risk
African American and Latino infants who are exposed to nitrogen dioxide, a component of air pollution emitted by cars, have a strong chance of later developing childhood asthma, according to researchers from UCSF, Kaiser Permanente in Vallejo, UC Berkeley, Children's Hospital and Research Center in Oakland, and Bay Area Pediatrics in Oakland.
In a new study, researchers reported that for every 5 parts per billion increase in nitrogen dioxide exposure during an infant's first year of life, there was a 17 percent increase in risk of developing asthma later in life. The study, which involved 3,343 Latino and 977 African American participants, is the largest to date to examine air-pollution exposure and asthma risk in American minority children.
Minorities tend to live in areas with relatively higher air pollution and have an elevated risk of developing asthma, the researchers said. They said the U.S. Environmental Protection Agency's national standard for nitrogen dioxide -- 53 parts per billion -- was too lax, considering that the study subjects were exposed to 19 parts per billion on average in their first year of life.
The study is available online in the American Journal of Respiratory and Critical Care Medicine.
- Stephanie M. Lee
BPA level in puberty linked to girls' weight
Pubescent girls whose urine has higher-than-average levels of bisphenol A, also known as BPA, have double the risk of being obese than girls with lower levels of BPA, according to a new study from Kaiser Permanente's Division of Research in Oakland.
BPA is a controversial chemical found in hard plastic bottles, the metal cans of food and beverages, sales receipts and dental sealants. Scientists and consumer health advocates say it is a harmful endocrine disruptor.
The study involved collecting urine samples from 1,326 boys and girls in Shanghai. Researchers found that in girls between 9 and 12, a higher-than-average level of BPA in urine -- at least 2 micrograms per liter -- was associated with twice the risk of having a body weight in the top 10th percentile for girls of their age in the same population. The link was even more pronounced among girls with extremely high levels of BPA.
This spring, California added BPA to its official list of reproductive toxicants. For now, a judge has removed it from the list in response to a lawsuit from the American Chemistry Council.
The study appeared June 12 in PLOS One.
- Stephanie M. Lee
Solar bionic eyes can transmit images to rats
A solar-powered retinal implant is capable of sending visual images to the brains of rats, according to Stanford researchers.
Similar technology could one day be used to correct blindness, which is often caused by disease or degeneration of the eye's retina.
In the study, researchers used a previously developed wireless photovoltaic retinal prosthesis to stimulate retinal signals in rats' brains and then monitor how they react. The device -- essentially a solar-powered bionic eye -- was inserted into the sub-retinal layers of the eye, adjacent to neurons that transmit visual information to the brain. Special video eyeglasses then beamed images directly into the implanted microchip.
The devices were implanted into the retinas of rats both with and without macular degeneration, a condition that usually occurs in older adults, causing gradual loss of central vision. Researchers found that the bionic retinas could successfully transmit images to the rats' brains. In rats with the eye disease that were implanted with the device, brain activity returned to normal.
The study appeared on June 18 in Nature Communications.
- Kristen V. Brown
Lack of sperm puts men at higher risk of disease
Men who are azoospermic and cannot produce sperm may be at more risk for developing cancer than the general population, according to researchers at Stanford.
About 4 million American men are infertile. Of those, about 600,000 men, or 1 percent of all reproductive-age men, are azoospermic, meaning there is no sperm in their ejaculate.
Researchers trailed 2,238 infertile men who visited a clinic at Baylor College of Medicine in Houston between 1989 and 2009. Those men were then tracked to see who turned up in the Texas Cancer Registry. Of those men, 451 were diagnosed with azoospermia.
Out of the 2,238 men, 29 developed cancer over an average of 5.8 years after their semen analysis compared with the expected 16.7 cancer cases. This suggested that infertile men were 1.7 times as likely to develop cancer as the population at large.
The azoospermic men, though, developed cancer at a much higher rate: They were three times as likely to be diagnosed with cancer than the overall population. Men diagnosed as azoospermic before age 30 were eight times as likely to develop cancer compared with men in the general Texas population of the same age. The men developed a wide range of cancers.
The study appeared on June 20 in Fertility and Sterility.
- Kristen V. Brown
(c)2013 the San Francisco Chronicle
Visit the San Francisco Chronicle at www.sfgate.com
Distributed by MCT Information Services