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(hat tip: CasesBlog)
Archives: 8/2005
Last week, we reported on a breakthrough in cell locomotion. Today, there’s news about a key protein involved in stopping cell movement — a relative of calmodulin called CIB1:
In illustrating the role that CIB1 plays in cell migration and PAK1 activation, the authors used a new method known as RNAi or RNA interference to knock down or reduce CIB1 expression in various cell lines. Cells with less CIB1 had less PAK1 activation and migrated faster. The authors also showed that the more CIB1 these cells had, the less likely they were to move.
So, another breakthrough made possible by RNAi. The authors elaborated on how this protein fits in known signaling pathways:
“CIB1 activates PAK1 before Rac and Cdc42,” said Dr. Leslie V. Parise, UNC professor of pharmacology, member of UNC Lineberger and the study’s senior author.
“The time course of PAK1 activation never synched up with the time course of Rac and Cdc42 activation; now we know why — it was probably CIB1 that was activating PAK1 and not the Ras relatives.”
Got that?
More from Dr. Parise’s Lab Page…
According to the MIT Techology Review, a startup called Chicago PT has developed an amazing rehabilitation robotics system for patients recovering from stroke who are relearning how to walk:
Chicago PT’s robot allows patients to make mistakes safely. The wheeled machine uses arms and a harness to give patients different degrees of support and guidance as their ability to walk improves. At first the robot might support all of a patient’s weight and slowly move straight forward, while the therapist rides along in a wheeled chair, guiding the patient’s legs through walking motions. Freed from having to support patients, therapists can “be really intelligent with their hands rather than being just a clamp to keep a person from falling over,” according to Brown.
As patients get stronger and more coordinated, a therapist can program the robot to let them bear more weight and move more freely in different directions, walking, kicking a ball, or even lunging to the side to catch one. The robot can follow the patient’s lead as effortlessly as a ballroom dancer, its presence nearly undetectable until it senses the patient starting to drop and quickly stops a fall. In the later stages of physical therapy, the robot can nudge patients off balance to help them learn to recover.
The company says that its robot can function in different customizable modes: walking exercise modes (walking, challenge, strength training, stabilization, body weight support) and balance exercise modes (perturbation, challenge, stabilization).
To learn more about the robot, go to the company’s website.
More at the MIT Techology Review…
The Washigton Post reports that NASA is developing a personal health monitor, that is similar to a blackbox found on planes.
NASA describes its device:
It’s a compact, portable, wearable device — a single piece of equipment that gathers a wide variety of vital signs. About the size of a computer mouse, a CPOD is worn around the waist. It’s comfortable enough to be worn while sleeping. It’s non-invasive. It takes only minutes to don. Importantly, it can track a person’s physiologic functioning as they go about their normal routine — they don’t have to be tethered to some stationary device. It can store data for eight-hour periods for later downloading; alternatively, it can send it wirelessly, in real time, to some other device…
The CPOD typically tracks heart performance, blood pressure, respiration, temperature, and blood oxygen levels. Using three tiny accelerometers, it also tracks a person’s movements — it can tell whether they’re running, for example, or spinning or tumbling.
And it can be reconfigured. If researchers choose, almost any kind of sensor could be plugged into the device. The CPOD could, for example, keep track of ambient air pressure, or monitor the concentrations of atmospheric gases.
To read more about the device at NASA…
Another interesting gene chip, this one for a common childhood malignancy called neuroblastoma, is being developed by scientists at The Children’s Hospital of Philadelphia and Thomas Jefferson University:
Genetics researchers have developed a customized gene chip to rapidly scan tumor samples for specific DNA changes that offer clues to prognosis in cases of neuroblastoma, a common form of children’s cancer. Rather than covering the entire genome, the microarray focuses on suspect regions of chromosomes for signs of deleted genetic material known to play a role in the cancer.
The investigators, from The Children’s Hospital of Philadelphia and Thomas Jefferson University, say their technique may be readily adapted for other types of cancer. The proof-of-principle study appears in the August issue of Genome Research.
One advantage of their technique is its flexibility, said co-author John M. Maris, M.D., a pediatric oncologist at The Children’s Hospital of Philadelphia. “As future research identifies other genes active in neuroblastoma, we can modify the microarray to include such regions,” he added…
Microarrays are silicon chips that contain tightly ordered selections of genetic material upon which sample material can be tested. When DNA bases from a sample bind to complementary sequences on the microarray, they cause fluorescent tags to shine under laser light. This is a signal that a particular gene variation is present in the sample.
“We can test DNA from peripheral blood and from the tumor, and we should see a loss of signal in the cancer,” said Dr. Fortina. He noted that the researchers can simultaneously evaluate seven chromosomal regions known to be involved in neuroblastoma.
Unlike gene expression microarrays, which detect varying levels of RNA to measure the activity levels of different genes as DNA transfers information to RNA, the current microarray directly identifies changes in DNA. “These DNA changes, involving gain or loss of genetic material, are important for neuroblastoma prognosis,” said Dr. Maris.
Researchers also report that this technique could potentially be used to identify other forms of cancer.
The press release…
More at the BBC…
The New York Times publishes a reader’s investigation into the morphology, physiology and evolutionary significance of the appendix. An interesting read.
It’s long been known that flying high in the atmosphere leads to increased exposure to radiation (one estimate we’ve heard: three cross-country flights is equivalent to a chest x-ray). Now, a new study concludes that those who work in the sky are at risk for cataracts:
Commercial airline pilots are reported to be at an increased risk for some cancers, but studies on the biological effects of their exposure to cosmic radiation have been limited, according to background information in the article….
Vilhjalmur Rafnsson, M.D., Ph.D., of the University of Iceland, Reykjavik, and colleagues conducted a case control study involved 445 men to determine whether employment as a pilot is associated with lens opacification…
“The odds ratio for nuclear cataract risk among cases and controls was 3.02 for pilots compared with nonpilots, adjusted for age, smoking status, and sunbathing habits,” the researchers report. The researchers found an association between the estimated cumulative radiation dose and the risk of nuclear cataract.
This isn’t all bad news, however. We recall a recent film focused on this phenomenon (which we didn’t see, having read the book). It involved several astronauts getting irradiated and coming back home with super-powers. So maybe the pilots can look forward to some positive effects from cosmic radiation.
More from Archives of Ophthalmology…
University College London reports that its team of scientists, in association with UCLA researchers, has developed a method of tracking a person’s thoughts with the use of fMRI (functional Magnetic Resonance Imaging):
In a study published in the latest issue of Current Biology, the UCL team found that brain activity measured in volunteers who were viewing a visual illusion could be used to accurately track their subjective experience while it underwent many spontaneous changes.
In the study, funded by the Wellcome Trust, John-Dylan Haynes and Geraint Rees presented volunteers with a visual illusion known as “binocular rivalry”. When very different images are presented separately to each eye, they compete for access to consciousness. Volunteers experience many spontaneous switches in their awareness, sometimes seeing one image and sometimes the other.
While volunteers experienced these spontaneous switches in awareness, the UCL team measured patterns of activity in their brains using functional MRI (fMRI) brain scanning. They found that brain activity could be used to blindly predict with high precision which of the two images a volunteer was perceiving, and how their conscious perception changed over several minutes of viewing. The study thus shows that it is possible to predict the changing stream of consciousness from brain activity alone.
Dr John-Dylan Haynes of the UCL Institute of Neurology says: “Previous research on visual perception has tended to focus on perception of static, unchanging scenes, ignoring the fact that our stream of consciousness is highly dynamic and our perception changes from second to second.
“Our study represents an important but very early stage step towards eventually building a machine that can track a person’s consciousness on a second-by-second basis.”
The press release…
More at the BBC…
Mike Elgan of The Raw Feed, brings to our attention the Somatom Sensation Cardiac 64 system by Siemens. According to the company, its cardiac diagnostic system is the world’s fastest computer tomograph. (We have covered a closely related SOMATOM Sensation 64 CT scanner earlier.)
Company’s pitch:
With our proprietary STRATON X-ray tube as a technological key element, Siemens provides you with the industry’s fastest rotation time of 0.33 s, virtually freezing the heart’s motion. Our 64-slice technology delivers unprecedented diagnostic detail with 0.4 mm isotropic resolution at any scan speed by using our exclusive z-Sharp Technology.
Speed4D™ Technology helps achieve a rapid and efficient cardiovascular workflow which facilitates a complete examination within 10 minutes–from scan to diagnosis. A comprehensive portfolio of leading cardiovascular applications completes the SOMATOM Sensation Cardiac 64 as the ultimate cardiac CT solution.
More pitching by Siemens…
The picture gallery…
