என் மனவெளியில் விதைக்கப்பட்ட வலிகளில் இருந்துதான் வாழ்விருப்பின் அடையாளம் அர்த்தப்படுத்தப்பட்டது. அவ்வலியின் உச்சமே என்னுள் மலைசுமக்கும் மறத்தையும் தந்தது. என் தல யாத்திரைகள் ஒவ்வொன்றும் தங்குமடங்களிலேயே நிறைவுற்றுப் போயினவெனினும்… மாற்றீடாய் தங்குமடங்களைத் தரிசனத்துக்கான தலங்களாய் ஆக்கும் திறனைத் தந்ததும் அவ்வலிகளே. வலிகள் ஏனோ வற்றாத ஊற்றாய்… பீறிட்டுக் கொண்டிருந்தன. இருந்தும் என் மனவாழம் அறியாமலவை தோற்றே போயின. குருசேஸ்த்திரத்தில் என் வாழ்வு பாண்டவர்கள் பக்கத்தில் இருந்தாலும் துரியோதனன் எனக்கு உயிர்ப்பிச்சை தந்துள்ளான். அர்ச்சுணன் கையில் நாகஸ்திரம் இருந்திருந்தால்… அது பலமுறை ஏவப்பட்டிருப்பதுடன் பல தலைகளையும் கொய்திருக்கும். காக்கப்பட்டவன் எவனெனினும் ‘காத்தவன்’ கடவுளல்லவா கணமேனும் அவனை மறக்கிலேன்!
Thursday, May 31, 2012
கணமேனும் அவனை மறக்கிலேன்!
என் மனவெளியில் விதைக்கப்பட்ட வலிகளில் இருந்துதான் வாழ்விருப்பின் அடையாளம் அர்த்தப்படுத்தப்பட்டது. அவ்வலியின் உச்சமே என்னுள் மலைசுமக்கும் மறத்தையும் தந்தது. என் தல யாத்திரைகள் ஒவ்வொன்றும் தங்குமடங்களிலேயே நிறைவுற்றுப் போயினவெனினும்… மாற்றீடாய் தங்குமடங்களைத் தரிசனத்துக்கான தலங்களாய் ஆக்கும் திறனைத் தந்ததும் அவ்வலிகளே. வலிகள் ஏனோ வற்றாத ஊற்றாய்… பீறிட்டுக் கொண்டிருந்தன. இருந்தும் என் மனவாழம் அறியாமலவை தோற்றே போயின. குருசேஸ்த்திரத்தில் என் வாழ்வு பாண்டவர்கள் பக்கத்தில் இருந்தாலும் துரியோதனன் எனக்கு உயிர்ப்பிச்சை தந்துள்ளான். அர்ச்சுணன் கையில் நாகஸ்திரம் இருந்திருந்தால்… அது பலமுறை ஏவப்பட்டிருப்பதுடன் பல தலைகளையும் கொய்திருக்கும். காக்கப்பட்டவன் எவனெனினும் ‘காத்தவன்’ கடவுளல்லவா கணமேனும் அவனை மறக்கிலேன்!
The Brain's Bat Signal
Marching orders. Microglia (green) migrate to injured neurons (red, top) but fail to do so when they cannot detect ATP (bottom).
Credit: EMBL/Peri
Microglia are the brain's resident security guards, surveilling the organ for damage and then crawling to the injury site to engulf dead neurons. Exactly how they detect problems was unclear, but researchers now show that they respond to an SOS signal from dying cells that is relayed throughout the brain. The finding may have implications for the treatment of Alzheimer's and other neurodegenerative diseases.
The study builds on previous work in zebrafish. Developmental biologist Francesca Peri of the European Molecular Biology Laboratory in Heidelberg, Germany, and colleagues created genetically engineered versions of the animals that produced microglia labelled with green fluorescent protein, a glowing compound frequently used in laboratory research. Zebrafish embryos have transparent brains, which allowed Peri and her team to track the microglia in real time under the microscope. The researchers reported in 2008 that the embryonic zebrafish brain is patrolled by about 20 of the cells.
Other researchers have shown that the ability of microglia to engulf dead neurons depends on adenosine triphosphate (ATP), a ubiquitous energy source and signalling molecule that is released from damaged cells. But ATP is rapidly degraded after being released from cells and cannot act as a long-range signal.
In the new study, Peri and her colleagues used lasers to destroy small numbers of neurons in the genetically modified zebrafish. In response, all the microglia migrated to the injury site, suggesting that they are indeed attracted by a long-range signal. But what could it be?
Further experiments revealed that injured cells initiate a wave of elevated calcium ion concentration that travels through the brain, and that the microglia only begin migrating when the wave reaches them. The wave sweeps through the brain at approximately 14 micrometers per second; the microglia turn their fingerlike appendages in the direction of the wave and then begin migrating toward the injury site within one minute. The spread of the wave was related to the extent of the damage, so killing fewer cells produced a smaller wave detectable only by microglia in the immediate vicinity. Adding a drug that blocked the calcium wave prevented microglia from migrating to the injury site, the team reports today in Developmental Cell.
In a final set of experiments, the researchers showed that the calcium waves are generated by a neurotransmitter called glutamate, which is released from damaged cells. Glutamate activates receptors on neighboring cells, causing them to propagate the wave and release ATP.
Microglial cells may malfunction in neurodegenerative disorders such as Alzheimer's disease, and there is some evidence that they worsen the damage caused by a stroke. The new findings, says Peri, implicate the calcium waves as potential targets for drug treatments. A drug could stop microglia in their tracks, for example, or reroute their migration.
The findings provide "a convincing explanation of how dying neurons attract microglia," says Frank Kirchhoff, a glia physiologist at the University of Saarland in Homburg, Germany, who was not involved in the study. He cautions, however, that the experiments should be repeated in mammals. Still, says neurophysiologist Alexej Verkhratsky of the University of Manchester in the United Kingdom, the microglial response to brain injury in zebrafish is "strikingly similar to that of mammals," suggesting that what Peri and her team observed is applicable to humans.
Kirchhoff is skeptical, however, that the calcium wave could be a drug target. Calcium is a "promiscuous" signal used by all cells for a wide variety of processes, he notes, and thus drugs that target it could have major side effects. And despite the utility of the zebrafish model for sussing out how microglia work, drug researchers are going to have to look elsewhere, says Verkhratsky. "[They're] limited as a disease model, because neurodegeneration does not occur in fish."
Posted by
Robert Karl Stonjek
Robert Karl Stonjek
Cognitive bias modification: A new approach to treating emotional disorders
(Medical Xpress) -- A new approach to preventing and treating anxiety and depression may be used to improve the emotional health of fly-in fly-out workers and people living in bushfire-prone areas.
The new approach, known as cognitive bias modification (CBM), has been developed by researchers involved in a world-leading study at The University of Western Australia.
Led by Winthrop Professor Colin MacLeod, from UWA's Elizabeth Rutherford Memorial Centre for the Advancement of Research on Emotion (CARE), the team has already published studies that show how CBM works for anxiety and addictions.
The treatment works by altering automatic and unconscious biases in the way people selectively process emotional information, using simple computer programs and smart phone applications. It can be effective after only a few 15-minute sessions and does not use drug or counselling therapy. All it requires is to sit in front of a computer or use a smartphone app and access a program that subtly alters harmful thought patterns.
CARE researchers are now working with the Australian Bushfire Cooperative Research Centre to evaluate whether CBM can be used to improve the emotional and behavioural preparedness of people exposed to the threat of bushfire.
Professor MacLeod also plans to investigate CBM's potential contribution to the prevention and remediation of depression in rural and remote areas of Western Australia, with a particular focus on how computer-delivered and smartphone-based CBM techniques can enhance the emotional health of fly-in fly-out workers. FIFO staff often work in isolated regions with limited access to traditional mental health services.
In addition, the Romanian Complex Exploratory Research Project program has awarded Professor MacLeod almost $2 million funding to lead three teams of Transylvanian researchers in a longitudinal study of anxiety and depression in adolescents. The study will combine CBM techniques with genetic and developmental approaches.
CARE has succeeded in attracting funding for several international collaborations. They include postdoctoral research fellow Dr Patrick Clarke and PhD student Ben Grafton, who will carry out collaborative work on CBM with colleagues at Oxford University and postdoctoral research fellow Lies Notebaert, funded by the Australian Bushfire CRC, whose work on CBM will involve collaboration with partners at Ghent University in Belgium.
Professor MacLeod has also won funding to support collaborative CBM research with colleagues at Harvard University where UWA PhD student Dan Rudaizky is currently working with Professor Rich McNally to evaluate a new iPhone app developed by CARE to produce beneficial cognitive change.
"We are delighted our researchers are committed to ensuring their internationally influential work also delivers practical benefits to the Western Australian community," Professor MacLeod said.
Provided by University of Western Australia
"Cognitive bias modification: A new approach to treating emotional disorders." May 28th, 2012. http://medicalxpress.com/news/2012-05-cognitive-bias-modification-approach-emotional.html
Posted by
Robert Karl Stonjek
Robert Karl Stonjek
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