Sunday, December 12, 2010

How Good Bacteria Naturally Fight Infection

Scientists have discovered how good bacteria in the body behave to boost the immune system and fight infection. Bacteria that flourish in the human body have long been known to help boost immunity, and now researchers know how it naturally happens.
Bacteria can cause harm while others help human health and fight against infection. The skin, respiratory tract and digestive system contain bacteria known as commensal bacteria that perform a variety of functions including boosting immunity. Bacteria in the digestive system, of which there are 500 to 1000 different species, are an example of good bacteria that naturally help fight infection.
A study from researchers at Loyola University Chicago, Stritch School of Medicine, led by Katherine L. Knight, PhD, studied spores from a type of bacteria found in the digestive tract from the Bacillus species. When bacteria make spores from their own DNA it is in response to stress – such as infection from bacteria and virus. When the researchers exposed an immune fighting blood cell, called a B-lymphocyte to the spores they found the lymphocytes increased in numbers to defend the body against infection.
They also found out that the spores and lymphocytes bind together to fight infection. The binding of spores to molecules on the immune fighting cells triggers division and reproduction of B-lymphocytes to help conquer infection.
The researchers suggest the discovery about how good bacteria fight infection could lead to novel ways to treat individuals with weakened immune systems. Dr. Knight warns research would take years, but now scientists know more about how good bacteria naturally fight infection.

Wednesday, December 8, 2010

Anesthesia Can Increase Post-Surgical Pain

The general anesthesia that puts patients into unconscious sleep so they do not feel surgical pain can increase the discomfort they feel once they wake up, say researchers from Georgetown University Medical Center. They say their findings, the first to scientifically explain what has been anecdotally observed in the clinic, may lead to wider use of the few anesthetics that don’t have this side effect, or to the development of new ones.
In the June 23rd issue of the Proceedings of the National Academy of Sciences (PNAS), the scientists report that “noxious” anesthesia drugs – which most of these general anesthetics are – activate and then sensitize specific receptors on neurons in the peripheral nervous system. These are the sensory nerves in the inflammation and pain pathway that are not affected by general anesthesia drugs that target the central nervous system – the brain and the spinal cord.
“The choice of anesthetic appears to be an important determinant of post-operative pain,” says the study’s lead investigator, Gerard Ahern, Ph.D., an assistant professor in the Department of Pharmacology at Georgetown University Medical Center. “We hope these findings are ultimately helpful in providing more comfort to patients.”
It has long been known that general anesthetics cause irritation at the infusion site or in the airways when inhaled, Ahern says. And investigators have also known that while they suppress the central nervous system, they can activate so called “pain-sensing” or nociceptive nerve cells on the peripheral nervous system – in fact, anesthesiologists often first use a drug to suppress inflammation and pain before delivering the anesthesia to put the patient to sleep.
But what has not been understood is the specific mechanism by which anesthetics affect sensory neurons, or that they can continue to cause pain and inflammation even as they are being used during surgery, he says.
The researchers tested the hypothesis that two specific receptor on the nerves cells (TRPV1 and TRPA1) which are often expressed together and which also react to other irritants, such as garlic and wasabi, were the ones activated by the noxious drugs.
“Plants produce chemicals such as capsaicin, mustard and garlic that were meant to stop animals from eating them. When they are eaten, the two main receptors that react to them are TRPV1 and TRPA1,” he says. In fact, TRPA1 is more commonly known as the mustard-oil receptor, and is a principal receptor in the pain pathway, Ahern says.
Experiments showed that general anesthetics appear to regulate TRPA1 in a direct fashion, and are thus responsible for the acute noxious effects of the drugs. Perhaps the strongest evidence is that mice bred without TRPA1 genes demonstrate no pain when the drugs are administered and used, Ahern says. “Most general anesthetics activate the mustard oil receptor, and animals that don’t have the receptor don’t have irritation,” he says.
The research team also found that nerve-mediated inflammation was greater when pungent (chemical irritants) versus non-pungent inhaled general anesthetics were used.
What both findings suggest is that sensory nerve stimulation throughout the body just before and during surgery adds to the pain that is felt after the patient is awake, Ahern says. “This is a provocative finding in terms of the clinical setting, because it was not really recognized that use of these drugs results in release of lots of chemicals that recruit immune cells to the nerves, which causes more pain or inflammation.”
Some general anesthetics do not activate the mustard-oil receptor, but they may not be as effective in other ways, Ahern says. “This tells us that there is room for improvement in these drugs.”

Thursday, December 2, 2010

Sign Language Via Cell Phone, You Heard Right

Deaf and hard-of-hearing individuals may soon have access to a cell phone capable of transmitting American sign language. University of Washington engineers are working on a device that can optimize compressed video signals for sign language.
Cell phone usage is ubiquitous: according to, 89 percent of Americans used a cell phone in 2009. But there are many people who are not included in this statistic because they have a medical challenge that does not allow them to use a traditional mobile phone.

Mobile Video Phones Make Sign Language Possible

The MobileASL (American Sign Language) team has been working to change that. They have improved the quality of the image around the hands and face on video phone transmissions, and they also use motion detection to identify when a person is signing, which can extend the phone’s battery life when the video is being used.
The University of Washington engineers recently completed its first field test of the video phone device along with 11 volunteers in a summer program for deaf and hard-of-hearing students. Eve Riskin, a UW professor of electrical engineering, explained that although they knew the cell phones worked in a lab, they wanted to test them in real life.
“This is the first study of how deaf people in the United States use mobile video phones,” she said. “The field study is an important step toward putting this technology into practice,” because it allowed the participants to test the phones in their daily lives for three weeks.
In this study, the average call duration was 90 seconds, and the volunteers made about 200 calls during the first two and a half weeks of the study. Although most of the study participants said they currently preferred to use texting or e-mail for distance communication, they rated their experience with the MobileASL phone as a positive one.
One of the volunteers noted that while texting is good for short messages, use of the video mobile phone is similar to “making a real phone call.” Texting can be confusing, while the MobileASL phone can eliminate that problem. Tong Song, a Chinese national who is studying at Gallaudet University in Washington, DC, pointed out that “with the MobileASL phone people can see each other eye to eye, face to face, and really have better understanding.”
New high-end cell phones, such as the iPhone 4 and the HTC Evo, offer video conferencing, but broadband companies have blocked video conferencing from their networks and will be offering expensive plans for heavy users. The UW engineers estimate that iPhone’s FaceTime video conferencing service uses nearly 10 times the bandwidth of MobileASL.
Riskin noted that “We want to deliver affordable, reliable ASL on as many devices as possible.” The UW engineers say the MobileASL system could be integrated with any of the new, high-tech devices that have a video camera on the same side as the screen. Hopefully it won’t be long before deaf and hard-of-hearing individuals have a cell phone they can use to communicate via sign language.