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Wednesday, December 7, 2005

Australian researchers say they have scientifically proven that stress causes sickness. The Garvan Institute in Sydney has discovered that a hormone, known as neuropeptide Y (NPY) is released into the body during times of stress. Their findings show the hormone can stop the immune system from functioning properly.

“Neuropeptide Y is one of those hormones that gets unregulated or released from neurones when stressful situations occur…it’s known for example that it regulates blood pressure and heart rates so your heart rate goes up but it hasn’t been known that it actually can affect immune cells as well,” said Professor Herbert Herzog, one of the researchers.

Herzog feels it is good to finally have proof of something people have suspected for so long.

“Now we have proven without doubt that there is a direct link and that stress can weaken the immune system and that makes you more vulnerable when you for example have a cold or flu and even in the more serious situations such as cancer can be enhanced in these situations,” said Herzog.

The Garvan Institute study centres on two key events that enable the human body to recognise foreign substances and control invaders. When our body encounters a pathogen (bacteria and viruses), the immune cells retain and interrogate suspects. Their activation is made possible by NPY. These cells then return to the lymph nodes, which are found all over the body, with information about the foreign invaders. The lymph nodes are where decisions about defence are made.

“Most of us expect to come down with a cold or other illness when we are under pressure, but until now we have mostly had circumstantial evidence for a link between the brain and the immune system,” said lead Garvan researcher, associate Professor Fabienne Mackay. “During periods of stress, nerves release a lot of NPY and it gets into the bloodstream, where it directly impacts on the cells in the immune system that look out for and destroy pathogens (bacteria and viruses) in the body.”

In the case of bacteria and viruses, TH1 cells are part of the attack team that is sent out on the ‘search and destroy’ mission. But when their job is done they need to be turned ‘off’ and the immune system reset. The same hormone, NPY, that activates the sentry cells now prompts the TH1 cells to slow down and die.

“Under normal conditions, circulating immune cells produce small amounts of NPY, which enables the immune cells on sentry duty and the TH1 immune cells to operate – it’s a yin and yang kind of situation. But too much NPY means that the TH1 attack is prevented despite the foreign invaders being identified – and this is what happens during stress,” added McKay.

The impact of stress on the body has been observed in athletes. Ph. D researcher at the University of Queensland, Luke Spence, together with the Australian Institute of Sport, studied elite and recreational athletes over five months.

They found elite athletes were more susceptible to respiratory diseases under stress.

“A lot of elite athletes put themselves through vast amounts of physical stress in their training, but also their emotional, psychological stress of feeling the pressure of Australia on their shoulders, wanting to compete and wanting to do their best,” said Spence.

It’s not just athletes who are prone to stress. Pressures at work and at home may cause emotional and mental stress that can be equally damaging. Almost a third of all work absenteeism in Australia is due to illness, costing employers over $10 billion a year.

“I think it has a huge impact for the work force and also for employers – if their employees are constantly stressed, constantly under pressure, they are more likely to get sick,” Spence said.

Further research could lead to the development of new drugs which may inhibit the action of the neuropeptide Y hormone.

Herzog warns people to minimise stress before it becomes a problem.

“Relaxation methods like yoga will help you to prevent that but there will still be people out there that are not responding to that and treatment by interfering with the system will be important,” he said. “There’s obviously some time until such a treatment will be available but this is something we will definitely work towards.”

The Garvan research will be published in the Journal of Experimental Medicine, Volume 202, No. 11.

Tuesday, October 4, 2005

President Bush has asked Congress to discuss the option of allowing him to deploy military resources if avian flu breaks out in America.

“I’m concerned about what an avian flu outbreak could mean for the United States and the world,” said the president in a conference today. The president also expressed concern that local response would be slow, given the precedent provided by the recent gulf coast hurricane disasters, the aftermath of which has triggered widespread criticism for what many view as instances of long-delayed and inadequate delivery on the part of the white house and congress. “I want there to be a robust discussion about the best way for the federal government, in certain extreme circumstances, to be able to rally assets for the good of the people,” the President said previously.

Avian flu is not currently able to easily pass from human to human, limiting epidemics. The president and others warn that the virus may mutate into a form that more easily spreads through social contact.

Sunday, June 28, 2020

Last month, a study conducted by archæologist Dr. Naomi Martisius and other researchers concluded Neanderthals living in Europe tens of thousands of years ago were more sophisticated than previously thought. The now-extinct species used to carefully select bones from a particular animal species to manufacture their bone tools, the research showed. The research was published on May 8 in Nature’s Scientific Reports journal.

Dr Martisius and her team used five bone tools discovered from Neanderthals’ sites in southwest France for this research. Four of these bone tools were found in a site called Abri Peyrony and the other one was from Pech-de-l’Azé I. These tools were just a few centimetres in size and were about 50 thousand years old, Dr Martisius told Wikinews. Microscopy analysis of these bone tools called lissoirs (smoothers) suggested Neanderthals used these tools for working animal skin to leathers.

The study stated the fauna of the sites were primarily medium-sized ungulates such as reindeer, in one layer nearly 90%. Despite the overabundance of medium-sized ungulates, Neanderthals used ribs of large bovids for making lissoirs. Dr Martisius told Wikinews this was likely due to the physical characteristics of the bovid ribs, which were “thicker” and “stronger” as compared to the “thin and flimsy ribs” of reindeers. In order to check the origins of the bone tools, the researchers used a technology called non-destructive Zooarchæology by Mass Spectrometry (ZooMS).

Instead of damaging the bone artefacts in order to discover its origins, the researchers collected collagen from the plastic containers in which these artefacts were kept. Collagen is a type of protein. These bone artefacts were kept in plastic containers: some were kept for about five years, some for just a few months. During this time, the collagen proteins from bone tools were stuck to the walls of its plastic containers. The collagen samples collected from the walls of the containers are broken into smaller molecules called peptides by using a chemical enzyme called trypsin.

After the trypsin has broken collagen fibres into peptides, it is analysed using a technology called Matrix-assisted laser desorption/ionization (MALDI) Time-of-Flight mass spectrometer (ToF MS). The assisting matrix is a coloured compound. The acidic peptide is combined with the matrix, vapourised, and peptides are released. Some of them are positively-charged particles which travel across a vacuum tube in an electric field. Depending on the weight of the peptides, these molecules reach the end of the vacuum tube at different instances of time, forming a spectrum. These graphs are like unique fingerprints of a species: they are different for different species of animals. Looking at the database of such graphs, taxonomic identifications of the collagen proteins came be made.

All four bone tools from Abri Peyrony gave positive results and showed that the bones were made from large bovids, even though reindeer were more abundant during that time. One of the advantages of using bovid ribs over reindeer’s thin ribs was the bovid ribs would be more resistant to breaking during flexion, Dr Martisius said.

Dr Martisius said such non-destructive ZooMS analysis was previously conducted, but for tools no older than a few centuries. She said such an analysis had never been previously conducted for artefacts so ancient.

Wikinews caught up with Dr Martisius to discuss this research in-depth.