Safest contraceptives not parents' picks
Updated 8:44 pm, Tuesday, February 12, 2013
Most effective not parents' top pick
Parents usually don't like to think much about their teenage daughters being sexually active, but most would hope that their girls at least use effective birth control.
A new study from UCSF takes a closer look at the range of perceptions parents have about contraceptive methods.
In a random survey of 261 parents and guardians with daughters ages 12 to 17, researchers found that parents perceived oral birth control pills, condoms, injectable contraception and emergency contraception as the most acceptable forms of contraception.
But only a minority approved of the forms that are most effective - implanted devices and intrauterine devices.
In addition, researchers were surprised to find that parents who saw their teens as likely to have sex were accepting of condoms and emergency contraception, but not the full array of options.
Future studies should examine the factors that influence how parents feel about different contraceptive methods, the researchers said. Their study appeared this month in the Journal of Adolescent Health.
- Stephanie M. Lee
Sodium intake far surpasses limits
If Americans consumed no more than the recommended amount of sodium, hundreds of thousands of lives could be saved over a decade, says a new study done in part by UCSF.
Adults should take in no more than 2,300 milligrams per day, according to dietary guidelines. But people in the United States are believed to consume much more than that, 3,500 milligrams per day, and the average American man puts away about twice as much as the suggested amount.
Excess sodium contributes to high blood pressure and cardiovascular disease, which accounts for more than 800,000 U.S. deaths annually.
Keeping sodium intake below the recommended level would save 500,000 to 850,000 lives over the next 10 years, largely by reducing the number of heart attacks and strokes, the study reported. Even gradually reducing sodium intake by 4 percent per year over 10 years would save 280,000 to 500,000 lives in that time.
- Stephanie M. Lee
Moles' touch-sensitive cells offer hope
The "star" on a star-nosed mole is perhaps not the most attractive of facial appendages in the animal kingdom, but it's full of touch-sensitive nerves that are intriguing and delighting UC Berkeley scientists.
The snout of these moles is crowned with an ostentatious, star-shaped strip of skin that contains more than 100,000 nerve fibers, the thread-thin extensions of nerve cells. That's the highest density of nerve cells on any known mammal skin surface.
What's fascinating, the scientists found, is that almost all of those nerve cells are touch-sensitive, not pain-sensitive. In humans and most other animals, the pain- and touch-receptive cells are intermingled in such a way that it's almost impossible to differentiate between the two.
The UC Berkeley team was able to identify genes associated with those touch-sensitive cells, along with the handful of pain-sensitive cells in the snout. Then they found the counterparts to some of those genes in humans.
Scientists hope that the discovery of those genes, and the pathways between the genes and the nerve cells, will provide other researchers with new targets for drugs to treat pain.
Results of the UC Berkeley research were published Jan. 30 in the journal Plos One.
Exposure to pathogen provides shield
Exposure to an infectious pathogen, whether through a vaccine or actual illness, appears to provide some unexpected but much appreciated protection against other microbes that a person has never come into contact with, Stanford researchers have found.
The scientists studied CD4 cells, which are a type of immune cell that circulate throughout the body and are usually the first to encounter an invading microbe. There are two types of CD4 cells - those that are "naive" and will raise a defense against pathogens they've never met, and those that have memories of the pathogens they come across and will mount specific attacks on them.
Scientists have long believed that those CD4 memories were almost entirely based on previous exposures to pathogens, either through a vaccine or an earlier illness. But when they looked at immune cells from 26 healthy adults, they found evidence of CD4 cells with "memories" of pathogens they'd never been exposed to, including HIV and the herpes virus. Meanwhile, immune cells taken from the umbilical cord blood of two newborns showed no such memory cells.
That implies that over the course of their lives, repeated exposure to a variety of pathogens helps protect people not just from those microbes but also from a wide variety of totally unrelated microbes. It means that vaccines may actually provide more protection than previously thought - and that eating dirt in childhood may serve a complex immunological purpose.
The Stanford research was published online Thursday in the journal Immunity.
- Erin Allday
Long-acting pain meds' testosterone tie
Men taking long-acting opioid medications for pain were almost five times more likely to have low testosterone levels than those taking short-acting opioid drugs, according to a Kaiser Permanente study.
Kaiser researchers studied 81 men between 26 and 79 years old who were treated at Kaiser's Santa Rosa Medical Center between January 2009 and June 2010. All the patients had been on a stable dose of opioids for at least three months, and none had a history of low testosterone.
The study compared short-acting opioids, which are taken every four to six hours, and long-acting ones, which may be taken every eight to 12 hours. Commonly prescribed opioids include oxycodone, sold under the brand name Oxycontin, and hydrocodone, or Vicodin.
Researchers found that 74 percent of men on the long-acting doses had low testosterone, compared with 34 percent of men on the short-acting drugs. Researchers hope the information will help doctors make prescribing decisions and are conducting a larger retrospective study of more than 1,500 patients.
The study was published online last month in the Clinical Journal of Pain.
Presence of harmful bacteria explained
Researchers at UC Davis have discovered why harmful bacteria flourish in the intestines of people suffering from inflammatory bowel disease, a disorder that includes ulcerative colitis and Crohn's disease.
Inflammatory bowel disease occurs when the immune system kills off beneficial bacteria, leading to stomach problems and inflammation of the intestines. Bad bacteria like E. coli prosper in the guts of people with the disease.
Using test-tube and animal models, the researchers have found out why. A byproduct of the intestinal inflammation is nitrate, which a class of bad bacteria called Enterobacteriaceae use to multiply, researchers found. That allows E. coli and other harmful bacteria to outnumber the good bacteria and results in further intestinal problems, stomach pain and diarrhea.
If researchers can find a way to block the pathway that leads to the formation of nitrate, it may be possible to improve the bacterial environment.
The study was published Friday in Science.
- Drew Joseph