The News – 6 June 2014

Overview

  • A new Australian-led study backs up the idea that if you’re very hot you can cool down by putting your hands and feet in cold water, but if you are really cold you need to put your body in warm water.
  • The way bacteria transfer between possums may offer some insight into the spread of human epidemics, according to a new Australian study published.
  • The discovery could dramatically improve snakebite treatment in tropical rural areas, particularly in the developing world, where snakebite is a major health issue.


Stories Discussed
News on Health Professional Radio. Today is the 6th June 2014. Read by Rebecca Foster.

http://www.abc.net.au/science/articles/2014/06/04/4018666.htm

Scientists now have some hard numbers to back up the current wisdom on how to deal with hypothermia and overheating.

A new Australian-led study backs up the idea that if you’re very hot you can cool down by putting your hands and feet in cold water, but if you are really cold you need to put your body in warm water.

“What we now know is the range of temperatures over which warming the hand and feet doesn’t work to warm the body,” says co-author Dr Nigel Taylor, an expert in extreme physiology from the University of Wollongong.

“Hands and feet are both radiators because they’ve both got a large surface area relative to their volume,” says Taylor.

But, he adds, it doesn’t mean that you can warm yourself up by transferring heat via the hands and feet into the body.

This is because heat transfer through hands and feet relies on blood flowing through them and when you are cold your body restricts blood flow to these areas to prevent loss of precious heat.

That explains why when we get really cold, our fingers go numb.

Taylor and colleagues have now modelled exactly how we control hand and foot blood flow across a range of temperatures.

Their study published in the European Journal of Applied Physiology, involved taking measurements of blood flow of the right hand and left foot of eight participants under various temperatures.

The graph shows that when your body is warm you can get huge changes in the blood flow of the hands and feet simply by applying cold water to them.

On the other hand, the graph shows that once the body temperature gets too cold, it doesn’t matter how much heat you apply to the hands and feet – it will make no difference.

This is because our hypothalamus has restricted blood flow to the hands and feet to stop them losing any heat, says Taylor.

“At some point an individual will lose the ability to warm him or herself. This is why people die from hypothermia,” he says.

In such a situation, it is important to heat the body’s core temperature up directly and this is best done by jumping into a warm bath or a sleeping bag with someone else, says Taylor.

http://www.abc.net.au/science/articles/2014/06/05/4019042.htm

The way bacteria transfer between possums may offer some insight into the spread of human epidemics, according to a new Australian study published.

Scientists from the Australian National University (ANU) looked at how social interactions between mountain brushtail possums influenced the transfer of the bacterium, Escherichia coli.

Surprisingly they found it was not just how much time the possums spent in contact with each other that determined the spread of E. coli, but rather what they were doing when they interacted.

E. coli is typically thought of as an environmental pathogen that is spread through ingestion of water or food that has been contaminated by faeces. But Blyton says the results, appearing in the journal Ecology Letters, indicate social interactions also play an important role.

“It suggests that the close contact of those individual possums facilitates transfer more than just the environment itself.”

Blyton and her colleagues measured the level of social interaction between the possums by fitting more than 30 individuals with collars, which recorded when the possums came within three metres of each other.

The collars also contained radio transmitters that allowed the scientists to track the specific location of the possums through the Victorian high country.

More than 100 strains of E. coli were identified among the possums, making it possible to map how different strains were shared between individuals.

http://www.abc.net.au/science/articles/2014/06/05/4018712.htm?site=science&topic=latest

Working out whether a snake has delivered venom with its bite may one day be determined by a simple blood test, new Australian research suggests.

The discovery could dramatically improve snakebite treatment in tropical rural areas, particularly in the developing world, where snakebite is a major health issue.

The work, previously published in Nature Scientific Reports, was presented this week at the Australian Society for Medical Research Annual Scientific Meeting in Sydney.

Senior author Dr Geoffrey Isbister, at the University of Newcastle’s School of Medicine and Public Health, says the delivery of snakebite antivenom is often delayed until symptoms appear. This can sometimes be too late.

Isbister says once signs of paralysis and muscle damage begin to appear, it cannot be reversed by antivenom.

The scale of the snakebite problem is large with the World Health Organisation recognising it about four years ago as a tropical disease.

Isbister says there are one to two million cases of snake envenomation, with a potential fatality rate of 100,000 deaths worldwide.

Snakebite treatment is hampered by the availability of antivenom; high reaction rates to antivenom; and difficulties in diagnosing envenomation to allow early antivenom treatment.

Isbister says the development of a cheap diagnostic test for envenomation that can be done at the bedside is critical in addressing these issues.

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