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Entries in Temperatures (2)

Monday
Apr092012

Are Temperature Swings Killing the Elderly?

Comstock/Thinkstock(BOSTON) -- After the warmest March on record, people are already talking about whether a scorching summer lies ahead.

It turns out that even small changes in summer temperature may pose a health risk to older adults with chronic medical conditions, according to a study published Monday in the Proceedings of the National Academy of Sciences.

Summers in which temperatures were more of a roller-coaster ride posed a greater hazard for people who had recently been hospitalized for a variety of illnesses than those summers with steadier temperatures.

The study looked at patients over the age of 65 who lived in one of 135 U.S. cities for over 20 years, and who had recently been hospitalized for heart attacks, chronic obstructive pulmonary disease, congestive heart failure, or diabetes.

Researchers found that for each extra Celsius degree in temperature swings, older people with these conditions experienced a 2.8 to four percent increased risk of dying, depending on their condition. Based on these increases in rates, they estimate temperature variability could account for thousands of additional deaths per year.

“People adapt to the usual temperature in their city,” says Joel Schwartz, professor of environmental epidemiology at the Harvard School of Public Health and senior author of the study. “That is why we don’t expect higher mortality rates in Miami than in Minneapolis, despite the higher temperatures. But people do not adapt as well to increased fluctuations around the usual temperature.”

“This finding, combined with the increasing age of the population, the increasing prevalence of chronic conditions such as diabetes, and possible increases in temperature fluctuations due to climate change, means this public health problem is likely to grow in importance in the future,” Schwartz said.

The study notes that death rates and temperature swings were dampened in cities with more green space. Could trees help prevent deaths going forward?

Another potential intervention could include warning systems to be put in place when temperatures change by a certain amount.

“These findings are the first to demonstrate health risks related to temperature variability,” says Patrick Kinney, director of the Columbia University Climate and Health Program.

The study looked at temperature changes independent of heat waves and ozone levels, which are also linked to an increased risk of death in the elderly. Future work will focus on why the elderly do not adapt as well to heat, and whether changes in heart rate and blood pressure may be driving the increased risk.

Copyright 2012 ABC News Radio

Friday
Mar302012

Keeping Chilly Lab Mice Warm: Key to Better Science?

Comstock/Thinkstock(NEW YORK) -- Joseph Garner imagines how much happier and healthier lab mice would be in a kinder, gentler environment than the stark cages in chilly laboratories -- and how that, in turn, might improve the outcome of research that underlies human medical advances.

In searching for “one thing we could put in every mouse cage in America that would make every mouse better off and would improve the quality of science done with every mouse,” he focused on a simple fact: mice are chronically cold and suffer from thermal stress.

That “one thing” that could be put in every cage is turning out to be shredded paper, which chilly mice use to build toasty, warm nests like the ones that wild mice build, according to a study published Friday in the journal PLoS One.

Given between a fifth and a third of an ounce of crinkly, coarse shredded paper called Enviro-dri, the mice went to work weaving “these beautiful igloos that are just incredible,” said Garner, an associate professor of comparative medicine at Stanford University in California. He conducted the research while at Purdue University in Indiana, with his then-graduate student Brianna Gaskill, now a postdoctoral scientist at Charles River Laboratories in Wilmington, Mass.

Because mice are nocturnal creatures, he said the lab mice were busy during nighttime hours in the lab, “very much like ‘Where the Wild Things Are.’ They’re very naughty at night.”

Garner has devoted much of the last seven years to understanding why 90 percent of compounds that look promising in animals go on to “fail in human trials.” He’s convinced their environment is part of the answer.

A mouse living in captivity is “a little bit like you or I living in a glass house being looked after by Tyrannosaurus rex,” he suggested. And a drafty house at that. That’s pretty close to conditions for mice, whose 98.4 degree body temperature is close to the 98.6 degrees of the lab technicians who tend to them. But air temperatures in research laboratories typically are kept between 68 and 75.2 degrees, putting them in a state of “cold stress.”

Garner is among the few U.S. scientists “really generating good data to support what animals ‘need and want,’ because animals clearly have their own needs,” said Joanne Zurlo, director of science strategy at the Center for Alternatives to Animal Testing at the Johns Hopkins Bloomberg School of Public Health in Baltimore. Without convincing proof that mouse well-being matters to scientific results, she said other scientists likely won’t buy into the idea that they need to make changes after “keeping mice in these conditions for umpteen years.”

The world’s largest breeder of laboratory mice, which has been supplying mice for the research, recognizes the important influence of laboratory conditions.

“The animal’s environment is a crucial factor in research,” said Kathleen Pritchett-Corning, director of research and professional services for Charles River Laboratories. “In research, we can control almost all aspects of an animal’s environment, but we don’t always know what’s best for the animal.”

She said the company has been “testing this material for our own use and have been very pleased with the results thus far.” She also suggested providing lab mice with nesting materials “could be a huge gain in welfare” and that other elements of lab animals’ environment are “ripe for study,” such as light levels, noise, air movement, type of bedding and feed.

“The healthier and more ‘normal’ the animal, the better the science,” said Pritchett-Corning, a veterinarian who has been working with mice for nearly 20 years. “The better the science, the more likely it is to lead to discoveries and advances that affect human health. It doesn’t matter what kind of animal it is, it deserves the best care we can provide.”

Copyright 2012 ABC News Radio







ABC News Radio