Year: 2013 (page 18 of 36)

mice are not good models for human inflammation

lab mouse

Lab mice might not be good models for humans in pharmacological studies

Mice are often used in biology to study pharmacological phenomena before studying a drug’s effects in humans. A paper recently published in PNAS suggests that mice might not be good models for human systems – at least when it comes to inflammation pathways.

In the paper, The Inflammation and Host Response to Injury, Large Scale Collaborative Research Program analyzed data sets from several studies. In these studies, researchers looked at gene expression after events that lead to inflammation like blunt trauma or burns. They compared the genes expressed in humans after such events to the gene expression of their analogues in mice. They found that there was very little correlation in the genes that a mouse expressed during inflammation and when compared to a human.

Also, when they compared the expression rates, they saw that both mice and humans saw the change in expression responded within the first 6 hours. But the time it took for expression to returned to normal lasted up to a year in humans, but only up to a week in mice.

The authors point out that many of the clinical trials based on mice studies fail. And none of the 150 treatments in clinical trials for inflammatory ailments has been successful.

For more information check out the original research by Junhee Seok et al. at PNAS.

does thinking wear you out?

The Thinker

Maybe. Maybe not.

From Popular Science:

That said, studies show that people do slow down after performing taxing mental tasks. One experiment, conducted by Samuele Marcora of the University of Kent, split subjects into two groups. Members of the first played a mentally challenging computer game. Those in the second group watched a documentary about trains or sports cars. Then everyone took an endurance test on an exercise bike. Marcora found that people who were “mentally exhausted” gave up pedaling more quickly than the documentary-watching controls. It was as if the heavy thinking had worn them out.

At the same time, Marcora found no correlation between the mental task and measures of their cardiovascular response, such as blood pressure, oxygen consumption, or cardiac output. In other words, the mental workout didn’t seem to slow their bodies so much as it appeared to skew their perception of how hard a given physical task might be.

baby cured of HIV

HIV medications

A baby, born in Mississippi 2.5 years ago appears to have been cured of HIV, the virus that causes AIDS. She is the first child, and only the second person ever, to have been thought to be cured of the infection. The cure was acheived thanks to an aggressive and early treatment with antiretroviral drugs just 30 hours after she was born. From NPR:

Gay decided to begin treating the child immediately, with the first dose of antivirals given within 31 hours of birth. That’s faster than most infants born with HIV get treated, and specialists think it’s one important factor in the child’s cure.

In addition, Gay gave higher-than-usual, “therapeutic” doses of three powerful HIV drugs rather than the “prophylactic” doses usually given in these circumstances.

Over the months, the baby thrived, and standard tests could detect no virus in her blood, which is the normal result from antiviral treatment.

Doctors then lost track of the baby for several months, as the mother went through “life changes.” But when they regained contact with the child, it showed a surprising lack of HIV virus. Again from NPR:

Gay expected to find that the child’s blood was teeming with HIV. But to her astonishment, tests couldn’t find any virus.

“My first thought was, ‘Oh, my goodness, I’ve been treating a child who’s not actually infected,’ ” Gay says. But a look at the earlier blood work confirmed the child had been infected with HIV at birth. So Gay then thought the lab must have made a mistake with the new blood samples. So she ran those tests again.

The results of this isolated event are prompting researchers to begin planning studies on whether this early and aggressive treatment can be more widely applied. It would have huge implications for AIDS treatment in the developing world where many children are infected with HIV during birth.

Also see coverage at the New York Times.

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