Posts Tagged ‘virus’
New Drug Can Treat Almost Any Viral Infection By Killing the Body’s Infected Cells
Viruses work by inserting themselves into a cell and hijacking its machinery for its own use. The invaded cell then creates more copies of the virus, which involves creating long strings of double-stranded RNA — which contains the virus’ genetic material, like DNA contains ours.
When the virus is done copying itself, its hostage cell usually dies, from the virus bursting through its walls (lysis), changes to the cell’s outer membrane, and from apoptosis, or programmed cell death.
Human cells have plenty of defenses against viral invasion, including proteins that attach to the double-stranded RNA, preventing the virus from replicating itself after successful invasion.
This new drug therapy combines those dsRNA proteins with a protein that induces apoptosis. It’s called a DRACO, Double-stranded RNA Activated Caspase Oligomerizer.
When one end of the DRACO binds to dsRNA, it signals the other end of the DRACO to induce cell suicide, an explains. In this way, the cell is killed before the virus can take over and eventually kill it anyway. If there is no dsRNA, the healthy cells are left alone.
“In theory, it should work against all viruses,” said Todd Rider, a senior staff scientist at MIT’s Lincoln Laboratory who invented the new technology.
A handful of drugs can target specific viruses by interfering with their replication process, through addition of modified DNA building blocks or the blocking of enzymes the viruses need to stimulate the replication process. But viruses are wily bugs, and they can evolve to resist these treatments.
The DRACO therapy could be effective because it targets the host cell, not just the virus.
Rider and colleagues are testing DRACO against more viruses in mice, according to MIT. Rider hopes to license the technology for trials in larger animals and for eventual human clinical trials, too.
[]
Using X-Ray Laser, Researchers Image a Single Virus, Destroying It In The Process
To achieve this, a team of scientists injected a stream of buffer and viruses into the path of the X-ray beam, which was pulsing with a 10-micron-diameter beam. From the resulting diffraction pattern of the photons collected, they were able to accurately rebuild the capsid of the virus.
The rebuilding of the virus isn’t what’s particularly noteworthy here. Rather, its the fact that the researchers were able to identify and collect a sufficient diffraction signal from a single exposure of a single particle even as the X-ray beam is destroying it. Higher energy X-rays and shorter pulses should increase the resolution, and researchers are working on that now.
Coupled with a second study in which researchers were able to image the nanocrystals in proteins via a similar femtosecond X-ray method (both papers were published in the journal Nature), it seems this kind of imaging is on the fast track toward resolutions that can image the structures of single molecules.
[]
New Anti-HIV Gel For Women Cuts AIDS Virus Transmission Chances in Half, Study Says
The women involved in the study used it only 60 percent of the time, and it was still effective -- meaning an even greater prevention rate is possible if it's used more frequently.
The study was published online Monday in Science.
The results still need to be confirmed, and scientists disagree about whether the protection it offers is sufficient to justify using the gel right away. But it's a major step in the fight to provide women another method besides condoms to protect themselves from infection. It's especially important in sub-Saharan Africa, where more than two-thirds of the world's HIV infections occur, .
Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, tells AP the gel marks the first time researchers have seen any microbicide make a statistically significant impact.
The gel was announced at the International AIDS Conference in Vienna, where thousands of scientists, policymakers and activists are gathered. The next few days will include announcements about new drug therapies and genetic research, as well as discussions about funding for research and prevention.
The study involved 900 South African women who were administered a special gel spiked with the AIDS drug tenofovir. The gel cut the risk of HIV infection by 50 percent after one year of use and 39 percent after 2 1/2 years, compared to a gel that contained no medicine, according to the study. The women used the gel only 60 percent of the time, and those who used it more often had higher rates of protection. Scientists say more frequent use is key -- the gel does not need to be changed.
Of the 444 women who received a placebo gel, 60 became infected with HIV, versus 38 infections in the 445 women who received the microbicide, reports. That's a statistically significant difference, the researchers say.
The gel is in limited supply, but 99 percent of the women in the study said they'd definitely use it if they knew it prevented the spread of HIV.
[, ]
Combining MRI with Atomic Microscopy, Researchers Get 3-D Images of Viruses, Cells
Traditional hospital MRI works by registering the very weak magnetic signals that come from hydrogen nuclei. A sample is doused with powerful magnetism that aligns the nuclei's magnetic spins, which in turn creates a strong enough signal for the machine to pick up.
The result is a 3-D image of the sample that is unparalleled in medical diagnostics, but there is a catch: In order to create a strong enough signal for the machine's antenna to pick up, traditional MRI requires trillions of atoms to be present in the sample. The best possible resolution is about three millionths of a meter.
While that's fine if you're imaging an entire organ, biologists want to image individual cells and even individual proteins. They can do so with electron microscopes, but not without damaging the samples. So researchers began looking for ways to leverage the power of MRI into higher resolution microscopy.
The idea of magnetic resonance force microscopy (MRFM) isn't new: a theoretical physicist named John Sidles proposed the idea in 1991. Since then researchers have struggled to make the idea pay off, and a collaboration between between MIT and IBM has improved the concept to the point that it can now image with resolutions as low as 5-10 nanometers (that's billionths of a meter).
They've done so by attaching the sample to a very small silicon cantilever (100 nanometers wide). A magnetic iron cobalt tip is eased up to the sample until the atomic spins of the atoms come under the iron cobalt's sway, which generates a tiny force on the cantilever. The spins are then flipped over and over again, causing the cantilever to sway repeatedly. A laser creates 2-D images from the displacement of the cantilever, which can be digitally stitched into a 3-D image.
It's not quite electron microscopy but it's very close, and it doesn't damage the living tissue under examination, meaning individual viruses and cells can be examined up close and in 3-D for the first time. Such up-close images of protein structures and cell bodies could teach researchers a lot about disease as well as help them figure out better ways to fight it.
[]
Mathematical Model Analyzes Facebook Networks to Prioritize Who Should Receive Vaccinations
People who are "bridges" among different social groups appear as good vaccination bets
The mathematical model focused on the fact that just a few individuals often form the links between different social groups. It also made use of data that came from back in 2005, when Facebook was only open to college students.
The relationships and interactions on five university campuses provided a useful starting scenario for the model to recognize clusters of people and predict bridges between them.
"When a new virus starts spreading, neither the time nor the necessary doses of vaccine to immunize everyone is available," said Marcel Salathe, a postdoc biology researcher at Stanford University. So you'd want a strategy that allows you to protect a population as much as possible given the limited resources that you have."
More details on the Stanford work appear in the April 8 issue of the PLoS Computational Biology.
Scientists have made growing use of social networking data that contains once-personal info. HP Labs researchers recently announced that they used Twitter data to of the latest Hollywood films. And the Pentagon's DARPA challenged people to sift through the disinformation available on social networks such as Twitter and hunt down the physical location of located around the U.S.
[]