Medicine & Health
edyong | October 6, 2009At 13 metres in length, Tyrannosaurus rex had little to fear from other predators. But it was occasionally attacked by an enemy far smaller than itself. In a wonderful piece of forensic palaeontology, Ewan Wolff from the University of Wisconsin has shown that the tyrant lizard king was often infected by a microscopic parasite, whose relatives still infect the birds of today. Potentially transmitted through bites from other tyrannosaurs, the parasite could have starved the infected animals to death.
Many of the large meat-eating dinosaurs have wounds on their heads that were clearly inflicted…
edyong | October 5, 2009Around 2600 years ago in Egypt, a woman called Irtyersenu died. She was mummified and buried at the necropolis at Thebes, where she remained for over two millennia before being unearthed in 1819. Her well-preserved body was brought to the British Museum where it was examined by the physician and obstetrician Augustus Bozzi Granville. It was the first ever medical autopsy of an Egyptian mummy and Granville presented his results to the Royal Society in 1825. His conclusion: Ityersenu died of ovarian cancer.
The mummification techniques of ancient Egypt were so good that Irtyersenu's corpse…
neurophilosophy | September 21, 2009THE vegetative and minimally conscious states are examples of what are referred to as disorders of consciousness. Patients in these conditions are more or less oblivious to goings-on in their surroundings - they exhibit few, if any, signs of conscious awareness, and are usually unable to communicate in any way. It is, therefore, extremely difficult to establish what these patients are experiencing, and the consciousness disorders are among the least understood, and most commonly misdiagnosed, conditions in medicine.
Although technologies such as functional neuorimaging have enabled…
edyong | September 16, 2009People with red-green colour blindness find it difficult to tell red hues from green ones because of a fault in a single gene. Their inheritance robs them of one of the three types of colour-sensitive cone cells that give us colour vision. With modern technology, scientists might be able to insert a working copy of the gene into the eye of a colour-blind person, restoring full colour vision.
You might think that the brain and eye would need substantial rewiring to make use of the new hardware, but Katherine Mancuso from the University of Washington thinks otherwise. She has used gene…
edyong | September 14, 2009This article is reposted from the old Wordpress incarnation of Not Exactly Rocket Science.
It's not just us who like to go travelling in the summer - flu viruses do it too. After a busy winter of infection, they turn into the gap-year students of the virus world. They travel round the world, meet new viruses, swap genetic material, and returning back, changed and unrecognisable (at least to our immune systems).
The success of flu viruses hinges on their ability to rapidly fool our immune systems by changing the proteins that line their surface. Every year, they put on a new disguise…
edyong | September 9, 2009Prions are proteins that have become bent out of shape. Their chain of amino acids folds up in an abnormal ways, and they can transmit this rogue alignment to their normal counterparts. As their numbers increase, they gather in large clumps that can kill neurons and damage brains. They most famously cause BSE in cows, CJD in humans and scrapie in sheep. But other mammals suffer from prion diseases too - the deer equivalent is called chronic wasting disease or CWD and it is shedding light on how prions are transmitted in the wild.
Gultekin Tamguney from the University of California, San…
edyong | September 5, 2009I was browsing a copy of New Scientist in the supermarket today and realised that I actually have a feature in it, having completely forgotten that it was coming out this week!
This one's on the fate of the oldest old - people aged 100 or over. This is one of the fastest rising demographics in the world and their numbers will surely swell even further with ageing populations and advances in modern medicine. The feature looks at what happens when people reach these extreme ages and what happens to them when they do.
It ended up being surprisingly optimistic. Far from being a helpless drain on…
edyong | August 12, 2009
When the bacteria that cause anthrax (Bacillus anthracis) aren't ravaging livestock or being used in acts of bioterrorism, they spend their lives as dormant spores. In these inert but hardy forms, the bacteria can weather tough environmental conditions while lying in wait for their next host. This is the standard explanation for what B.anthracis does between infections, and it's too simple by far. It turns out that the bacterium has a far more interesting secret life involving two unusual partners - viruses and earthworms.
A dying animal can release up to a billion bacterial cells in every…
edyong | August 10, 2009People infected with the bird flu virus - influenza A subtype H5N1 - go through the usual symptoms of fever, aching muscles and cough. The virus is so virulent that 60% of infected humans have died. But according to a study in mice, the infection could also take a more inconspicuous toll on the brain, causing the sorts of damage that could increase the risk of diseases like Parkinson's and Alzheimer's many years after the virus has been cleared.
The link between influenza and Parkinson's disease is hardly old but certainly controversial. Previous studies have found no traces of flu genetic…
edyong | August 3, 2009Swine flu has made the world all too aware of the possibility of diseases making the leap from animal hosts to human ones. Now, we know that another disease made a similar transition from chimpanzees to humans, several thousand years ago. This particular infection is caused by a parasite, and a very familiar and dangerous one - Plasmodium falciparum, the agent responsible for malaria.
Transmitted by the bite of mosquitoes, P.falciparum infects over 500 million people every year. Its closest relative is a related parasite, Plasmodium reichenowi, which infects chimpanzees. Leading an…
edyong | July 9, 2009As the world is now painfully aware, pigs can act as reservoirs for viruses that have the potential to jump into humans, triggering mass epidemics. Influenza is one such virus, but a group of Texan scientists have found another example in domestic Philippine pigs, and its one that's simultaneously more and less worrying - ebola.
There are five species of ebolaviruses and among them, only one - the so-called Reston ebolavirus - doesn't cause disease in humans. By fortuitous coincidence, this is also the species that Roger Barrette and colleagues have found among Philippine pigs and even…
edyong | July 8, 2009It's 1964, and a group of Canadian scientists had sailed across the Pacific to Easter Island in order to study the health of the isolated local population. Working below the gaze of the island's famous statues, they collected a variety of soil samples and other biological material, unaware that one of these would yield an unexpected treasure. It contained a bacterium that secreted a new antibiotic, one that proved to be a potent anti-fungal chemical. The compound was named rapamycin after the traditional name of its island source - Rapa Nui.
Skip forward 35 years and rapamycin has made a…
edyong | July 2, 2009The swine flu pandemic is well under way. With the WHO citing almost 60,000 laboratory-confirmed cases at the time of writing, the race is truly on to understand more about the virus. Now, two new studies have painted a fresh but partly contradictory picture about two of the virus's most important aspects - its infectivity (its ability to spread from host to host) and its virulence (its ability to cause disease in a host). These two traits will largely determine the threat that the virus poses, especially in relation to more familiar garden varieties of seasonal flu.
Both groups, one based…
edyong | June 29, 2009The swine flu pandemic (S-OIV) currently sweeping the world is the result of an influenza H1N1 virus that made the leap from pigs to humans. But this jump is just the latest leg of a journey that has taken over 90 years and shows no signs of finishing.
Today's pandemic is a fourth-generation descendant of the 1918 flu virus that infected around a third of the world's population. This original virus is an incredible survivor and one that has spawned a huge legacy of daughter viruses. By importing and exporting its genes, it has contributed to several new strains that have been responsible for…
edyong | June 11, 2009In the time since the words "swine flu" first dominated the headlines, a group of scientists from three continents have been working to understand the origins of the new virus and to chart its evolutionary course. Today, they have published their timely results just as the World Health Organisation finally moved to phase six in its six-tier system, confirming what most of us already suspected - the world is facing the first global flu pandemic of the 21st century.
The team, led by Gavin Smith at the University of Hong Kong, compared over 800 viral genomes representing a broad spectrum of…
edyong | May 28, 2009It's a diverse melting-pot of different groups, with hundreds of different cultures living together in harmony, many sticking to their own preferred areas. No, not London, New York or any other cosmopolitan city; I'm talking about your skin. It may all look the same to you, but to the bacteria living on it, it's an entire realm of diverse habitats.
From a microscopic perspective, the hairy, moist surface of your armpits is worlds apart from the smooth, dry skin of your forearms. Even though they are separated by mere inches, these patches of skin are as different to their microscopic…
edyong | May 9, 2009
Immunity to viral infections sounds like a good thing, but it can come at a price. Millions of years ago, we evolved resistance to a virus that plagued other primates. Today, that virus is extinct, but our resistance to it may be making us more vulnerable to the present threat of HIV.
Many extinct viruses are not completely gone. Some members of a group called retroviruses insinuated themselves into our DNA and became a part of our genetic code. Indeed, a large proportion of the genomes of all primates consists of the embedded remnants of ancient viruses. Looking at these remnants is like…
edyong | April 29, 2009HIV is an elusive adversary. The virus is so good at fooling the immune system that the quest for an HIV vaccine, or even a countermeasure to resist infections, has spanned two fruitless decades. But maybe a defence has been lurking in our genomes all this time.
Nitya Venkataraman from the University of Central Florida has managed to reawaken a guardian gene that has been lying dormant in our genomes for 7 million years. These genes, known as retrocyclins, protect monkeys from HIV-like viruses. The hope is that by rousing them from their slumber, they could do the same for us. The technique…
edyong | April 28, 2009The autism spectrum disorders (ASDs), including autism and its milder cousin Asperger syndrome, affect about 1 in 150 American children. There's a lot of evidence that these conditions have a strong genetic basis. For example, identical twins who share the same DNA are much more likely to both develop similar autistic disorders than non-identical twins, who only share half their DNA.
But the hunt for mutations that predispose people to autism has been long and fraught. By looking at families with a history of ASDs, geneticists have catalogued hundreds of genetic variants that are linked to…
edyong | April 26, 2009It is literally very difficult to mend a broken heart. Despite its importance, the heart is notoriously bad at regenerating itself after injury. If it is damaged - say, by a heart attack - it replaces the lost muscle with scar tissue rather than fresh cells. That weakens it and increases the chance of heart failure later on in life. No wonder that heart disease is the western world's leading cause of death and illness.
If that picture seems bleak, two teams of scientists have some heartening news for you. The first has found that the heart does actually have the ability to renew its cells,…