Posts Tagged "Cold weather"

Using less than a drop of blood, a new test can reveal nearly every virus a person has ever been exposed to, scientists reported on Thursday.

The test, which is still experimental, can be performed for as little as $25 and could become an important research tool for tracking patterns of disease in various populations, helping scientists compare the old and the young, or people in different parts of the world.

It could also be used to try to find out whether viruses, or the body’s immune response to them, contribute to chronic diseases and cancer, the researchers said.

“I’m sure there’ll be lots of applications we haven’t even dreamed of,” said Stephen J. Elledge, the senior author of the report, published in the journal Science, and a professor of genetics at Harvard Medical School and Brigham and Women’s Hospital.

“That’s what happens when you invent technology — you can’t imagine what people will do with it,” Dr. Elledge said. “They’re so clever.”

The test can detect past exposure to more than 1,000 strains of viruses from 206 species — pretty much the entire human “virome,” meaning all the viruses known to infect people. The test works by detecting antibodies, highly specific proteins that the immune system has made in response to viruses.

Tried out in 569 people in the United States, South Africa, Thailand and Peru, the blood test found that most had been exposed to about 10 species of virus — mostly the usual suspects, like those causing colds, flu, gastrointestinal illness and other common ailments.

Source: New York Times

This test is not yet commercially available but our comprehensive physicals include testing for individual viral infections and inflammation.

As temperatures increased above 50°F (10°C) in several large U.S. cities, risk of kidney stones also increased significantly researchers said.

A study of 60,433 privately insured patients across five cities — Atlanta, Chicago, Dallas, Los Angeles, and Philadelphia — found that the maximum risk for kidney stone presentation occurred within 3 days of a high daily temperature and was likely mediated by an effect on patients’ hydration.

The risk was statistically significant in all cities except Los Angeles, according to the paper, published online in Environmental Health Perspectives.

Cumulative relative risks for a mean daily temperature of 86°F (30°C) versus 50°F were:

• Atlanta (1.38, 95% CI 1.07-1.79)
• Chicago (1.37, 95% CI 1.07-1.76)
• Dallas (1.36, 95% CI 1.10-1.69)
• Los Angeles (1.11, 95% CI 0.73-1.68)
• Philadelphia (1.47, 95% CI 1.00-2.17)

The five cities represent climates in which 30% of the world’s population lives, according to study author Gregory Tasian, MD, MSc, at the University of Pennsylvania, and colleagues.

Using a time series design and distributed lag nonlinear model, researchers collected private health insurance claims data from 2005-2011 as well as weather data for the selected cities. Tasian and colleagues examined presentation for kidney stones within a 20-day window of temperature exposure.

Cases tended to occur within a few days after episodes of extreme temperature, with a first peak at about 2 to 3 days and a second at 4 to 6 days.

“We were expecting to find a short lag time between heat and presentation, so it wasn’t really surprising that the lag time was detected within a week,” Tasian told MedPage Today.

Tasian and colleagues hypothesized that dehydration is the causal mechanism between the effect of heat and stone presentation. When patients who are already at risk get dehydrated, calcium and uric acid become more supersaturated, and calcium stones begin to form, they said.

“It’s all linked to fluid. Saying heat leads to fluid loss would be the direct link,” said Allan Jhagroo, MD, a professor of nephrology at the University of Wisconsin who was not associated with the study.

The researchers also hypothesized that the hotter weather may have led to stone formation in patients exposed to hotter weather who would have normally developed stones at a future time.

Colder weather was associated with a relative risk in Atlanta, Chicago, and Philadelphia, perhaps because patients stay indoors where it can be hotter. It’s also conceivable that hydration may suffer during extremes of cold (when indoor humidity, which was not measured in the study, is usually low) as well as hot weather.

Outdoor humidity was measured, but was not found to be a predictor for kidney stones.

The researchers also suggested that the number of hot days in a year is probably a better indicator of kidney stone risk than mean annual temperature. Atlanta, for example, had almost twice the rate of kidney stones compared with Los Angeles but had a similar mean temperature. It had, though, on average 53 days a year in which the daily mean temperature was higher than 80°F. Los Angeles had only 10.

Dallas had 324 days hotter than 86°F during the period, 20 times more than such days in Atlanta, the next closest city. But it had the same risk increase. Tasian and colleagues suggested that the population of Dallas may have adapted to the local climate, spending more time indoors and drinking more fluids. They also noted that their data were sparse for extreme weather, and their statistical methods may have flattened the associations somewhat.

A previous study reported by MedPage Today found that, as temperatures across the U.S. increase because of climate change, the prevalence of kidney stones may be expected to grow. Tasian said that more research needs to be done to see how the risk of kidney stones may change with temperature increases.

The authors acknowledged several limitations to the study. They had no data on individuals’ actual exposure to outdoor temperatures, which would vary. All the patients had commercial insurance and may spend more time indoors, with air conditioning, than those with public or no insurance. It is also possible that temperature differentially affects subgroups such as older versus younger patients.

Additionally, the research was concerned only with presentation at the hospital and not stone formation.

Jhagroo suggested that this left open the question of whether “warmer weather leads to passage, or warmer weather leads to both formation and passage.”

Source: Med Page Today

“Temperature training” may be what is missing from your weight-loss plan. New evidence suggests that regular exposure to mildly cold air may help people lose weight by increasing the amount of energy their bodies have to expend to keep their core temperature up, researchers say.

In other words, warm, cozy offices and homes may not be ideal places for those who want to lose weight. In fact, being able to control the ambient temperature might be partly responsible for the rise in obesity rates in industrial societies, said researchers from the Netherlands in a study published last week in the journal Trends in Endocrinology & Metabolism.

“Since most of us are exposed to indoor conditions 90 percent of the time, it is worth exploring health aspects of ambient temperatures,” said study researcher Wouter van Marken Lichtenbelt of Maastricht University Medical Center. “What would it mean if we let our bodies work again to control body temperature?”

The human body withstands the cold by shivering, which produces heat; this provides one explanation for why cold temperatures may promote weight loss. Studies have shown that people expend five times more energy when shivering than when they are resting.

The body uses more energy when the mercury drops for other reasons as well. For example, a type of fat called brown fat, which burns calories rather than storing them, is activated in response to cold. In young and middle-aged people, heat production through brown fat can account for up to 30 percent of the body’s energy budget, the researchers said.

A previous study from researchers in Japan found a decrease in people’s body fat after they spent two hours per day for six weeks in a room with a temperature of 62.6 degrees.

The new study also found that people get used to the cold over time. After spending six hours a day at 59 degrees for 10 days, people in the study not only had more brown fat, the participants also said they felt more comfortable and shivered less when exposed to lower temperatures.

Although a 59-degree room would probably be too cold for most people, it’s possible that room temperatures in the mid-60s would also activate brown fat, the researchers said.

The long-term effects of regular exposure to cold are still unclear and require further investigation, but evidence suggests that training the body to tolerate cooler air may indeed help burn calories, the researchers said.

“Similarly to exercise training, we advocate temperature training,” the researchers said. “More-frequent cold exposure alone will not save the world, but is a serious factor to consider in creating a sustainable environment together with a healthy lifestyle.”

However, exposure to cold weather still poses a risk for hypothermia, loss of electricity and heat, etc. It’s a good reminder that everyone should have an emergency preparedness kit available at all times. At the Presidential Healthcare Center, we provide advice regarding emergency preparedness supplies and can make a Presidential Healthcare Center Emergency Backpack for you if need be.

Source: Washington Post