Saturday, June 25, 2011

Scientific snippets

The following are in this week's new Scientist:

RABIES may not deserve its reputation.

It looks like the immune system sometimes defeats the disease on its own.

This month 8-year-old Precious Reynolds of California became only the sixth person known to survive rabies without receiving a vaccine within a few days. Doctors treated her with the experimental Milwaukee protocol, plunging her into a drug-induced coma to take her brain “offline” while immune cells scrubbed away the virus. But the protocol is no miracle cure: tried with at least 35 people, only five had previously survived.

On 15 June, Iran put its second ever satellite, Rasad-1, into orbit

It is 260 kilometres above the Earth. Iran hopes to use the experience to launch a monkey into space this year and, by 2019, a human. The worry is that such rockets could also be used to fire missiles at targets on Earth.

At 15 kilograms, Rasad-1 may be tiny, but it is a boost to Iran's space capabilities, says Brian Weeden of the Secure World Foundation think tank, headquartered in Washington DC. “Now that they've put two satellites up there, that indicates perhaps it wasn't a fluke the first time. It demonstrates that their rocket technology is pretty good.”

Rasad-1 is reportedly taking low resolution images of Earth. Its purpose seems mainly to gain experience in launching and operating satellites. Iran's state-run television company says the country will launch a monkey into orbit on a one-way trip “later this year”.

There has been concern in western countries, especially in the US, about Iran's space programme, enhanced by suspicions that the country is trying to develop nuclear weapons, which it denies. However, the rocket that launched Rasad-1 (pictured) appears to be very similar in capability to the Safir-2 rocket used to launch Iran's first satellite in 2009, which is not powerful enough to send a nuclear warhead as far as the US.

More Nuclear ReactorsI

In the wake of the nuclear meltdown at the Fukushima Daiichi power plant in Japan in March, several countries have announced plans to reject nuclear power. Japan will not build any more reactors. Germany plans to phase out its nuclear power plants, Switzerland will not replace its reactors, and last week Italy voted against starting a nuclear programme. But the UK has announced plans to replace another 7 of its nuclear power stations.

The International Atomic Energy Authority lists 65 reactors under construction, and those figures are just the tip of the iceberg because they do not include reactors that are contracted to be built, or those being planned. Neither do they acknowledge the significance of the United Arab Emirates being on course to become the first country to go nuclear since China in 1985: the UAE has signed a deal with a consortium led by the Korea Electric Power Corporation to build four reactors. Saudi Arabia is following suit, having announced earlier this month that it will build 16 reactors by 2030. Turkey plans to build two new plants.

Of 52 countries that have recently asked the IAEA to help them start a nuclear programme only 10 meet all of their criteria, Jewell says. Another 10 had the motivation and resources but were politically unstable. That second group includes Egypt, the most likely to gain nuclear power of the five north African countries with stated intentions. Continuing political uncertainty in Egypt makes nuclear an unlikely option there in the near term, however.

Meanwhile, the plants already under construction in established nuclear countries are feeling the ripples of Fukushima. Just under half of the reactors listed as under construction by the IAEA are in China – but following events in Japan, the Chinese government has suspended approvals for new plants while it reviews their safety.

Can we sense magnetism?

Sea turtles, pigeons and honeybees are among the animals that have an incredibly useful skill that we do not – they can sense the Earth's magnetic field with their bodies. But perhaps our magnetovision is just latent – when a light-sensitive protein was transferred from humans to fruit flies, the insects adopted the protein for their own magnetovision.

Steven Reppert of the University of Massachusetts in Worcester and his colleagues study cryptochromes – light-sensitive proteins that regulate the circadian clocks of many creatures. Reppert knew that cryptochromes also help fruit flies and birds sense the Earth's magnetic fields, and he wanted to see whether human cryptochromes could do the same thing. To find out Reppert replaced those found in fruit flies with a human version, hCRY2, which is found in the retina.

The mutant flies could be trained to associate a sugar reward with a magnetic field. When given the option to fly down either a magnetised or non-magnetised arm of a maze they opted for the magnetised one. Flies genetically engineered to lack cryptochrome altogether were indifferent to the magnetic field in one arm and were evenly distributed down both arms of the maze. Apparently, fruit flies have no problem using human cryptochrome to sense magnetic fields, which implies humans have the hardware to do the same, but for some reason do not activate the ability.

Gains form Chinese Medicine?

For more than 2000 years Chinese doctors have treated Parkinson's-like symptoms with gou teng, a herb with hook-like branches. Early this year, 115 people with Parkinson's were given a combination of Chinese medical herbs, including gou teng, or a placebo for 13 weeks. At the end of the study, volunteers who had taken the herbs slept better and had more fluent speech. Li Min, a traditional Chinese doctor at Hong Kong Baptist University who was not involved in the study, thinks she knows how it works. Parkinson's is caused by the destruction of brain cells that produce dopamine. Studies have suggested this destruction is caused by an abundance of a protein called alpha-synuclein, triggering interest in substances that get rid of the protein by encouraging the programmed cell death – autophagy – of the cells that contain it.

Li's team has found one such substance, the alkaloid isorhy, in gou teng. It induced autophagy at a similar rate to rapamycin, which has recently been touted as a candidate for Parkinson's treatment. However, because rapamycin depresses the immune system, it would have serious side effects, whereas gou teng has been taken for centuries with no apparent ill effects. Li, who presented her results at last month's Keystone Symposia on Molecular and Cellular Biology in Whistler, British Columbia, will begin trials of synthesised isorhy in rodents later this year.

Meanwhile, Zhaoxiang Bian, also at Hong Kong Baptist University, is developing a drug called JCM-16021 for Irritable bowel syndrome using seven herbal plants, based on a formulation called tong xie yao fang, which has been used to treat IBS in China since the 1300s.

In 2007, Bian gave 80 people with IBS either JCM-16021 with Holopon – a drug that interrupts nerve impulses responsible for digestion – or Holopon alone. After eight weeks, 52 per cent of those given JCM-16021 with Holopon had reduced IBS symptoms, compared with 32 per cent of those given just Holopon.

IBS is partly caused by high levels of serotonin in the gut. Last year, Bian found that giving JCM-16021 to rats with IBS-like symptoms broke down serotonin in their bowel faster than normal, reducing their discomfort. His team has since isolated several compounds in JCM-16021 that block serotonin's activity in the rat gut, including magnolol, a herb taken from magnolia trees.

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