[silk] Lock and load
http://www.physorg.com/news157655203.html Light-activated 'lock' can control blood clotting, drug delivery March 30th, 2009 Scientists have shed new light -- literally -- on a possible way to starve cancer tumors or prevent side effects from a wide range of drugs. A lock-like molecule designed by University of Florida chemistry researchers clasps or unclasps based on exposure to light. In laboratory tests, the chemists put the lock on an enzyme involved in blood clotting. They then exposed the enzyme to visible and ultraviolet light. The clasp opened and closed, clotting the blood or letting it flow. The results suggest that the biological hardware could one day be used to prevent the formation of tiny blood vessels that feed tumors. The little lock could also be placed in drugs, giving doctors the ability to release them only on diseased cells, tissues or organs -- maximizing their efficacy while preventing side effects from damage to healthy tissue. Endoscopic lights inserted into the patient could unlock the drugs when desired -- or, the drugs could be activated by simply exposing the skin nearest the targets to near-infrared light, which penetrates the skin. The major idea is to use photons to manipulate a molecule's function, said Weihong Tan, the V.T. and Lois Jackson chaired professor of chemistry and a member of the UF Shands Cancer Center. The next step would be to deliver therapeutic re-agents at the site, for example, of a cancer tumor. A paper about the research is set to appear next week in the online edition of the Proceedings of the National Academy of Sciences. Youngmi Kim, who earned her doctorate in chemistry from UF in December and is the paper's first author, said the lock has two interconnected parts: a molecule that responds to light, and a short, single strand of active DNA known to scientists as an aptamer. In its natural state, the aptamer binds with an enzyme called thrombin, which regulates blood clotting. The aptamer inactivates the enzyme, which allows the blood to flow freely. Kim's locking version, however, folds itself into a curved, closed shape when exposed to visible light. That prevents it from binding, or clasping, which means the enzyme remains active and the blood clots. But with ultraviolet light, the curving shape dissolves, freeing the aptamer to clasp, inactivating the enzyme, and allowing the blood to flow freely. Tan said further research could point to ways to use the lock in combination with thrombin or other substances, natural or artificial, to inhibit the growth of blood vessels around tumors or the delivery of nutrients through those vessels. The locking molecule could also be affixed to a wide range of other drugs to remain inactive until they reached their targets and light is applied, he said. Not only that, but Tan said he has made progress on related research using similar mechanisms to make hydrogels that liquefy or gel around a target in response to light. Source: University of Florida (news : web) -- ((Udhay Shankar N)) ((udhay @ pobox.com)) ((www.digeratus.com))
[silk] Now we know - How scratching can stop an itch
Thought this was interesting :) http://news.bbc.co.uk/2/hi/health/7976606.stm *Scientists have shown scratching helps relieve an itch as it blocks activity in some spinal cord nerve cells that transmit the sensation to the brain.* However, the effect only seems to occur during itchiness itself - scratching at other times makes no difference. While it is widely-known scratching relieves an itch, the physiological mechanisms for how this works are little understood. The University of Minnesota study appears in Nature Neuroscience. Previous research has suggested that a specific part of the spinal cord - the spinothalamic tract - plays a key role. Nerve cells in this area have been shown to be more active when itchy substances are applied to the skin. Blocks activity The latest work, in primates, found that scratching the skin blocks activity of nerve cells in the spinothalamic tract during itchiness - preventing the spinal cord from transmitting signals from the scratched area of skin to the brain. Researcher Dr Glenn Giesler hopes the work could lead to ways to relieve chronic itch effectively for the first time. However, he said more information was still needed about the chemistry underpinning the effect. Professor Gil Yosipovitch, an expert on itching from Wake Forest University in North Carolina, said the finding was potentially significant. He said: Although there is a long way to go, methods that can induce a pleasurable scratch sensation without damaging the skin, via mechanical stimuli or drugs that can inhibit these neurons, could be developed to treat chronic itch. However, Professor Yosipovitch stressed that scratching and itching were complex phenomena involving factors such as emotions as well as physiology. The main open question is what happens in patients who suffer from chronic itch where scratching may actually aggravate itch perception. Professor Patrick Haggard, of University College London, said: We all know that scratching helps alleviate itch, but this elegant study helps to show how this mechanism works. It's an interesting illustration of a very general principle of the brain controlling its own inputs, in this case by making movements that triggers an interaction between scratchy touch and itch. Dr Paul Bays, based at UCL's Institute of Cognitive Neuroscience, agreed that the study provided an important part of a physiological explanation for how the sensation of itch is reduced. However, it is still unclear why scratching should have this effect, or why it is only effective for itches and not for painful sensations - which are transmitted to the brain through the same pathway. Kiran
Re: [silk] Now we know - How scratching can stop an itch
--- On Tue, 7/4/09, Kiran K Karthikeyan kiran.karthike...@gmail.com wrote: From: Kiran K Karthikeyan kiran.karthike...@gmail.com Subject: [silk] Now we know - How scratching can stop an itch To: silklist@lists.hserus.net Date: Tuesday, 7 April, 2009, 12:25 PM Thought this was interesting :) Talk of a straight line: There was a young lady of Natchez Whose clothes were always in patchez When asked why She said in reply When Ah itchez, Ah scratchez. http://news.bbc.co.uk/2/hi/health/7976606.stm *Scientists have shown scratching helps relieve an itch as it blocks activity in some spinal cord nerve cells that transmit the sensation to the brain.* However, the effect only seems to occur during itchiness itself - scratching at other times makes no difference. While it is widely-known scratching relieves an itch, the physiological mechanisms for how this works are little understood. The University of Minnesota study appears in Nature Neuroscience. Previous research has suggested that a specific part of the spinal cord - the spinothalamic tract - plays a key role. Nerve cells in this area have been shown to be more active when itchy substances are applied to the skin. Blocks activity The latest work, in primates, found that scratching the skin blocks activity of nerve cells in the spinothalamic tract during itchiness - preventing the spinal cord from transmitting signals from the scratched area of skin to the brain. Researcher Dr Glenn Giesler hopes the work could lead to ways to relieve chronic itch effectively for the first time. However, he said more information was still needed about the chemistry underpinning the effect. Professor Gil Yosipovitch, an expert on itching from Wake Forest University in North Carolina, said the finding was potentially significant. He said: Although there is a long way to go, methods that can induce a pleasurable scratch sensation without damaging the skin, via mechanical stimuli or drugs that can inhibit these neurons, could be developed to treat chronic itch. However, Professor Yosipovitch stressed that scratching and itching were complex phenomena involving factors such as emotions as well as physiology. The main open question is what happens in patients who suffer from chronic itch where scratching may actually aggravate itch perception. Professor Patrick Haggard, of University College London, said: We all know that scratching helps alleviate itch, but this elegant study helps to show how this mechanism works. It's an interesting illustration of a very general principle of the brain controlling its own inputs, in this case by making movements that triggers an interaction between scratchy touch and itch. Dr Paul Bays, based at UCL's Institute of Cognitive Neuroscience, agreed that the study provided an important part of a physiological explanation for how the sensation of itch is reduced. However, it is still unclear why scratching should have this effect, or why it is only effective for itches and not for painful sensations - which are transmitted to the brain through the same pathway. Kiran Add more friends to your messenger and enjoy! Go to http://messenger.yahoo.com/invite/
Re: [silk] Lock and load
Endoscopic lights inserted into the patient could unlock the drugs when desired Are direct drug-delivery mechanisms really more invasive than endoscopic lights? -Dave I know a surgeon who installed rubber mats in his horse's (very irregularly shaped) stall/run, by hand. When I asked if it wouldn't have been a better use of his time to have let someone else do the work, he simply replied you know, I *like* to cut.
Re: [silk] Bangalore silk meet up
Usha and I will be joining if it is on Friday and in FB :-) If we have a headcount, I can try to arrange a small discount... So its final then, lunch on Friday? I can't make lunch during the weekend, but can do dinner. Kiran
Re: [silk] Bangalore silk meet up
We're in for Friday. Shall we say 11:30 am? 1. Venkat 2. Usha On 4/8/09, Kiran K Karthikeyan kiran.karthike...@gmail.com wrote: Usha and I will be joining if it is on Friday and in FB :-) If we have a headcount, I can try to arrange a small discount... So its final then, lunch on Friday? I can't make lunch during the weekend, but can do dinner. Kiran -- Sent from my mobile device
Re: [silk] Bangalore silk meet up
On Wed, Apr 8, 2009 at 10:21 AM, Venkat Mangudi's Silk Account s...@venkatmangudi.com wrote: We're in for Friday. Shall we say 11:30 am? 1. Venkat 2. Usha 3. Udhay -- ((Udhay Shankar N)) ((udhay @ pobox.com)) ((www.digeratus.com))
Re: [silk] Bangalore silk meet up
s...@venkatmangudi.com wrote: We're in for Friday. Shall we say 11:30 am? 1. Venkat 2. Usha 3. Udhay 4. Kiran
