This along with the rate of antibiotic diffusion are used to estimate the bacteria's sensitivity to that particular antibiotic. In general, larger zones correlate with smaller minimum inhibitory concentration (MIC) of antibiotic for that bacteria. This information can be used to choose appropriate antibiotics to combat a particular infection.
Kirby-Bauer antibiotic testing (KB testing or disk diffusion antibiotic sensitivity testing) is a test which uses antibiotic-impregnated wafers to test whether particular bacteria are susceptible to specific antibiotics. A known quantity of bacteria are grown on agar plates in the presence of thin wafers containing relevant antibiotics. If the bacteria are susceptible to a particular antibiotic, an area of clearing surrounds the wafer where bacteria are not capable of growing (called a zone of inhibition).
This along with the rate of antibiotic diffusion are used to estimate the bacteria's sensitivity to that particular antibiotic. In general, larger zones correlate with smaller minimum inhibitory concentration (MIC) of antibiotic for that bacteria. This information can be used to choose appropriate antibiotics to combat a particular infection.
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An international team of scientists has recently determined that about 5 percent of people who have high blood pressure exhibit this condition because thy have benign, hormone-producing tumors on the adrenal cortex.
These are glands located on top of the kidneys, whose role is to regulate the emission of stress-related hormones. They produce chemicals such as cortisol (the stress hormone) and epinephrine, better known as adrenaline. The adrenal (suprarenal) glands also play a role in regulating the functions of the kidneys, via a hormone called aldosterone. This chemicals regulates the osmolarity of plasma in these vital organs. When the adrenal cortex becomes host to tumors, these forms of cancer can develop in such a way that they influence the hormonal balance of the body. High blood pressure is a consequence of this. In the new investigation, researchers from the Uppsala University, in Sweden, and the Yale School of Medicine, in New Haven, Connecticut, managed to determine the genetic cause that triggers the formation of these hormone-producing tumors. Details of the new investigation and its conclusions appear in the February 11 issue of the top journal Science. The main mechanism through which adrenal tumors influence blood pressure is the elevated production of aldosterone. The condition is called aldosteronism, and its primary manifestation is elevated blood pressure. While this is established knowledge, scientists did not know why the tumors developed in the first place. But investigators from the UU Endocrine Surgery Unit, and their American colleagues, were able to discover the causal mechanism in the new study. The investigation was conducting via a new scientific imaging method, called exome sequencing. Investigators took sample of both tumor and normal tissue, and then applies exome sequencing to a number of genes in the two types of cells. A specific potassium channel, called KCNJ5, was discovered to play a critical role in tumor growth and development. The channel usually regulates the passage of various molecules through the cellular membrane, in and out of the cells. When it malfunctions, tumors appear, and the production of aldosterone spikes. “The discovery may help to improve diagnostics in connection with primary aldosteronism and cases of severe blood pressure elevation,” explains UU Department of Surgical Sciences researcher Peyman Björklund. “The mutated potassium channel also represents a potential target molecule for treatment of the tumors in question,” he concludes. Though it may seem counter intuitively at first, not all heart attacks are felt as they occur. In fact, it is estimated that roughly 30 percent of all such attacks go unnoticed, and without symptoms. Researchers are now working on ways of using blood to determine when such a heart event occurred.
Scientists at the Massachusetts Institute of Technology (MIT), in Cambridge, say that the bloodstream holds telltale indications that a heart attack has occurred for several days after the actual event. Working in collaboration with colleagues from the Massachusetts General Hospital (MGH) Cardiovascular Research Center, the MIT experts have recently developed a new implantable device, that can be used to detect the signs left behind by “stealth” heart attacks. The new device functions fairly simple. It is capable of monitoring the blood levels of three very important proteins, which are produced in larger quantities than average during a heart attack. In a set of experiments the investigators conducted on unsuspecting lab mice, they showed that the implants are very effective at detecting when levels of the three proteins spike in the bloodstream. While these devices are not for everybody, they could prove to be very useful for people who are known to have an elevated risk of experiencing a heart attack. If this happens, then doctors would know a lot faster than they do today. They could then start administering treatments earlier than is possible today, which could contribute to increasing patients' overall chances of survival. This would also prevent more severe heart disease from developing. Details of the new device, and the associated investigation, were published in the February 13 issue of the esteemed scientific journal Nature Biotechnology. The study was led by MIT professor of materials science and engineering Michael Cima, also the senior author of the research paper. “If you go to the ER thinking you’ve had a heart attack, they take a blood sample and analyze it for these specific proteins. If you think about cancer, there aren’t generally agreed-upon markers,” Cima explains. What's so interesting about this study is that the new device was constructed so that it can bind to and detect three biomarkers at the same time. “This shows how generalizable this technique is,” says MGH Center for Molecular Imaging Research associate professor Lee Josephson, who was not a part of the research team. A team of experts in the United States, which took the world of genetics by storm last year, announced recently that it managed to reach a new impressive milestone in their quest to develop synthetic life.
The group was able to create the first non-biological, self-replicating species on Earth, by synthesizing a bacterial genome from scratch, and then allowing it to take over a cell. Investigators responsible for this feat were led by genome pioneer J. Craig Venter, the founder and leader of the J. Craig Venter Institute. This is a non-profit genomics research institute dedicated to research in genomics, its societal implications, and its potential applications. Scientists with the Institute were also involved with the creation of the first self-replicating synthetic bacterial cell in the world. This achievement was announced on May 20, 2010, and elicited reactions from all circles, including US President Barack Obama. Now, the same team strikes again. What the experts did was basically use a computer to develop a bacteria-like genome, and then constructed it from scratch. The construct was then inserted into a cell that had its own genetic material removed beforehand. This is “the first self-replicating species we’ve had on the planet whose parent is a computer,” Dr. Craig Venter says. But there are those who say that his line of work is dangerous, and potentially threatening for the world's future. Unlike any other technology that came before, synthetic self-replicating organisms can, well, self-replicate. Advanced robots can do the same too, as can structures used in nanotechnology applications. This means that it's a lot easier for experts to lose control over their own creations. But people are not accustomed to think about the individual importance of each scientific breakthrough, given the large number of innovations that are announced every single day. Venter himself synthesized the genome of Mycoplasma mycoides, a dangerous parasite that targets vertebrates, and which is resistant to a large number of antibiotics, Daily Galaxy reports. But the genomics pioneer is convinced that things are looking up. “This is an important step, we think, both scientifically and philosophically,” he explained in an interview for Science. The journal is publishing his discoveries this week. “It’s certainly changed my views of definitions of life and of how life works,” the expert concludes. |
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