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Here are some of the latest health and medical news developments, compiled by the editors of HealthDay:
Study Offers New Insight Into Cancer Origins
Scientists who found that 21 major genetic mutations account for 97 percent of the 30 most common cancers say their achievement is a major milestone in cancer research.
Identifying the causes of these mutations could lead to new cancer treatments. Smoking, exposure to ultraviolet light and some other causes of these mutations are known, but more than half are a mystery, BBC News reported.
The scientists made their discovery after analyzing mutations in 7,042 samples taken from the 30 most common cancers. The effort was led by the Wellcome Trust Sanger Institute in the U.K.
"I'm very excited. Hidden within the cancer genome are these patterns, these signatures, which tell us what is actually causing cancer in the first place -- that's a major insight to have," Sanger Institute Director Sir Mike Stratton told BBC News.
"It is quite a significant achievement for cancer research, this is quite profound. It's taking us into areas of unknown that we didn't know existed before," Stratton said. "I think this is a major milestone."
The study was published in the journal Nature.
This is a "fascinating and important study" that identifies several new processes driving the development of cancer, Nic Jones, chief scientist at Cancer Research U.K., told BBC News.
"Understanding what's causing them could be an extremely important way to get the bottom of how cancer develops in the first place -- and this will lead to new ways to prevent and treat the disease," Jones explained.
Hospital Tech in Hepatitis C Outbreak Pleads Guilty
A hospital technician linked to a multistate hepatitis C outbreak pleaded guilty Wednesday to federal drug charges and will be sentenced at a later date.
David Kwiatkowski, 34, worked in 18 hospitals in seven states before being hired at Exeter Hospital in New Hampshire last year. Forty-six people in four states have been diagnosed with the same strain of hepatitis C carried by Kwiatkowski, the Associated Press reported.
The Michigan native was accused of stealing painkiller syringes from Exeter Hospital and replacing them with saline-filled syringes contaminated with his blood.
Under a plea deal enabling him to avoid charges in other states, Kwiatkowski pleaded guilty to 14 charges of drug theft and tampering. He faces 30 to 40 years in prison, the AP reported.
Florida Boy Infected with Brain-Eating Amoeba
A 12-year-old Florida boy has been infected with a rare, brain-eating amoeba found in warm freshwater, the U.S. Centers for Disease Control and Prevention says.
Zachary Reyna's family told TV station WBBH that he was kneeboarding in a water-filled ditch near his house on Aug. 3 and slept the entire next day. This was unusual, so his family took him to the hospital, where he underwent brain surgery. He is currently in the intensive care unit at the Miami Children's Hospital.
The Naegleria fowleri amoeba enters the body through the nose and travels to the brain. An expert told CNN that it kills 99 percent of people who get it.
This is the second such infection in the U.S. in less than a month. The other case involved 12-year-old Kali Hardig in Arkansas. She is now in rehab and listed in fair condition.
The same experimental drug used to treat Hardig was released by the CDC to treat Reyna, but it's not clear if the drug has been, or will be, given to him, CNN reported.
FDA Looking at Sleep Drugs' Impact on Driving
The impact that sleep drugs have on people's ability to drive the next morning is a new area of concern for the U.S. Food and Drug Administration.
Recent evidence appears to confirm what many people have long suspected: that the effects of sleep drugs can persist well into the next day. This is something that consumer advocates have warned about for years, The New York Times reported.
Last month, the FDA rejected an application for a new sleep drug from Merck, in part because tests showed that some people had difficulty driving the day after taking the drug suvorexant.
The FDA says it is taking a closer look at all sleep medicines on the market and will ask manufacturers to conduct more extensive driving tests for all new sleep drugs. The agency also plans to take a closer look at any drug that causes drowsiness, The Times reported.
NYC Meningitis Outbreak Halted by Vaccination Campaign
An aggressive vaccination campaign appears to have halted a bacterial meningitis outbreak among gay and bisexual men in New York City, according to health officials.
Twenty-two men have been infected and seven of them have died since 2010. The number of infections accelerated last fall and early this year and raised fears of a new AIDS-type epidemic, The New York Times reported.
City health officials launched a vaccination campaign and at least 16,000 people have been vaccinated. The last case of the highly lethal disease was in mid-February, which is the longest period of time without a new case since January 2012.
"We think that because we've had no cases in six months, we have to conclude that enough of the population has been vaccinated to provide protection at least for now," said Dr. Jay Varma, the city's deputy commissioner of disease control, The Times reported.
"Whether or not this provides protection for several years is something that we'll have to see," Varma added.
Mouse Study Finds Even Small Amounts of Added Sugar in Diet Harm Health
Eating added sugars, even at levels that are within recommended limits for humans, could be toxic, a new mouse study suggests.
Researchers gave mice an amount of extra sugar in their diet that matched the current recommendation for humans of no more than 25 percent of a person's diet, Fox News reported Tuesday. When compared to a control group of mice that were not fed the added sugar, the first group of mice died sooner, produced fewer babies and gained control of less territory during their 32-week life spans.
"The odd things is our mice passed their physicals. They really didn't look any different from control animals," first study author James Ruff, a doctoral graduate from the University of Utah, told Fox News.
In terms of obesity rates or fasting insulin, glucose or triglyceride levels, there were no differences between the two groups of mice, the researchers reported in Nature Communication.
Only cholesterol levels were higher in the sugar-fed mice, and female mice who were fed sugar had more trouble clearing glucose from their bloodstream, Fox News reported.
"One common criticism of animals studies is they look at doses irrelevant to the human condition, which makes them more difficult to translate," Ruff said in explaining the amount of sugar they gave to the one group of mice. "We wanted to pick something relevant to human health."
The researchers noted that even though the effect on health was small, most people would be concerned that the added sugars everyone eats every day might be causing harm in the long run.