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London: HIV the virus which causes Aids may be getting less powerful, according to researchers. A team at the Institute of Tropical Medicine, in Antwerp, compared HIV-1 samples from 1986-89 and 2002-03. They found the newer samples appeared not to multiply as well, and were more sensitive to drugs - some other studies argue they are becoming more resistant, reports the BBC. The researchers, writing in the journal Aids, stressed their work in no way meant efforts to prevent the spread of HIV should be scaled down. Keith Alcorn, senior editor at the HIV information charity NAM, said it had been thought that HIV would increase in virulence as it passed through more and more human hosts. But the latest study suggested the opposite is actually true. "What appears to be happening is that by the time HIV passes from one person to another, it has already toned down some of its most pathogenic effects in response to its host's immune system," he said. "So the virus that is passed on is less 'fit' each time. "This would suggest that over several generations, HIV could become less harmful to its human hosts. "However, we are still far from that point - HIV is still a life- threatening infection." Sept 29, 2005 Mother of all brains emerged 700 million years ago (Go To Top) Sydney: A new study published in Arthropod Structure and Development journal claims that all brains originated from a single common ancestral brain that emerged at least 700 million years ago - only once before insects, birds and humans underwent its own evolutionary course. "What we see today in humans, insects and all other multicellular animals with a central nervous system are probably just variations of one ancient scheme. What this ancestral brain looked like, we do not know. Its architecture might have been very simple, but the basic genetic mechanisms and the principal chemical setup was already," Discovey News quoted Dr Rudi Loesel, a scientist at RWTH Aachen University in Germany, as saying. The researchers also don't know what the creature that contained that brain looked like. While some speculate it could have been a segmented flatworm, others think it was a more complex creature. According
to ABC Online quoting the report, the scientists said that they can't
rely on fossil evidence, because neuronal tissue is not preserved over
time. Instead, they compare the brain architecture of living species,
identify similarities and then try to find common characteristics that
would have belonged to the mother brain. "Taking the similarities in
brain biology in such distantly related animal groups like insects and
mammals into account, the origin of the brain - the common ancestral
brain - must have already evolved before the major animal phyla diverged,
which was approximately 700 million years ago," Loesel said. At around
that time, invertebrates and vertebrates each branched off from the
tree of life. The emergence of the common brain likely occurred just
before this branch-off, because brains and associated characteristics
of insects known to exist then and now share key aspects with human
and other animal brains. Loesel said that evidence for the once-shared
brain can be seen in certain neurotransmitters, which function similarly
in most brains, and in genes that regulate the circadian clock that
controls sleep-wake cycles. The same circadian clock genes in insects
have been found in mammals. Professor Walter Gehring, a cell biologist
at the University of Basel, Switzerland, also said that insects and
animals share common characteristics related to the brain, such as eyes.
"The observation that mammals and insects, which have evolved separately
for more than 500 million years, share the same master control gene
for eye morphogenesis [the process of cell differentiation into various
tissues and structures] indicates that the genetic control mechanisms
of development are much more universal than anticipated," Gehring said. High dose aspirin may cause temporary deafness (Go To Top) Washington: A study by Rice University researchers has shown that high doses of aspirin can cause membranes to thin, soften, rupture more easily, which may lead to temporary deafness. According to the study published in the recent issue of Biophysical Journal, salicylate - an active metabolite of aspirin - weakens lipid membranes. These mechanical changes disrupt the lining of the stomach, which functions to protect underlying tissue from the acidic contents of the gut. The changes may result in aspirin-related deafness by interfering with the proper function of prestin, a transmembrane protein that's critical for mammalian hearing. "Our studies found that membranes exposed to physiological concentrations of salicylate were thinner, more permeable, easier to bend and more likely to rupture," said study co-author Robert Raphael. All
cells are surrounded by membranes, ultrathin barriers of fatty acids
that are just a few nanometers thick. Membranes act like a skin, sealing
off the inner machinery of the cell from the outside world. About 40
percent of human proteins are "transmembrane" proteins, molecules that
stick through the membrane like a needle through a cloth. First identified
five years ago, prestin is a transmembrane protein found in the inner
ear. A motor protein, prestin is thought to act like a piezocrystal,
converting electrical signals into mechanical motion. In the outer hair
cells of the cochlea, prestin acts as a molecular motor, causing the
cells to move rhythmically and amplify the sounds we hear. "If you change
the mechanical properties of the membrane, you will likely affect the
biophysical processes that take place there, including those that are
mediated by membrane proteins like prestin," Raphael said. "Effectively,
our results proved that salicylate can stabilize holes that spontaneously
form in lipid membranes, thus increasing membrane permeability. Our
study highlights the pivotal role played by the mechanical properties
of membranes in biological processes," he said. Health intact 10 yrs after stem-cell transplantation (Go To Top) Washington: A new study by Fred Hutchinson Research Cancer Center researchers has found that overall health and quality of life remains intact even 10 years after stem-cell transplantation for blood cancer. "In many areas of health, our survivors are undistinguishable from case-matched controls who participated in this study and had not had a transplant," said lead investigator Karen Syrjala. Published in the recent issue of the Journal of Clinical Oncology, the study found that transplant survivors and case- matched controls reported similar rates of hospitalization and outpatient medical visits. They had similar rates of diseases and conditions such as asthma, diabetes, high blood pressure, high cholesterol, osteoporosis and hypothyroidism, and they had similar psychological health, marital satisfaction and employment. However, Syrjala and colleagues also found that transplant patients had a higher incidence of musculoskeletal problems, such as stiffness and cramping; poor long-term sexual health; and increased urinary frequency and leaking than the control group. Long-term survivors also had higher use rates of anti-depressant and anti-anxiety medications even though reported rates of depression and anxiety were about the same as that of the control group. The
study also reported potentially under-diagnosed problems among survivors
such as the bone-thinning disease osteoporosis and hypothyroidism because
the reported rates of these diseases were lower than expected. Syrjala
and colleagues made an important and positive observation among 10 percent
of the survivors who had suffered relapse and were in complete remission
at the time of the study. "The fact that patients can relapse and still
have healthy, full lives 10 years later and look like everyone else
who has gone through a transplant without relapse is really good news.
In the past, relapse after a transplant was always thought to be a very
bad sign for quality of life," she said. Cholera can be treated with ciprofloxacin (Go To Top) Dhaka:
A new study published in The Lancet states that severe cholera in
children can be treated effectively with a single dose of the antibiotic
ciprofloxacin. Debasish Saha from the Centre for Health and Population
Research, Bangladesh and his colleagues compared the effectiveness of
a 3- day, 12-dose course of erythromycin with a single-dose of ciprofloxacin.
Thy found that treatment with ciprofloxacin was successful within 48
hours in 60 percent of cases, compared with 55 percent in children who
were treated with erythromycin. Ciprofloxacin was more effective than
erythromycin at reducing vomiting and stool number and volume, they
said. However, single-dose ciprofloxacin was inferior to erythromycin
in eradicating the cholera bacteria-Vibrio cholerae-resulting in those
treated with ciprofloxacin excreting the bacteria for longer than those
treated with erythromycin. "For infections caused by susceptible strains
of V cholerae, single-dose ciprofloxacin achieves clinical outcomes
similar to or better than, those achieved with 12-dose erythromycin
treatment in childhood cholera, but is less effective in eradicating
Vcholeraefrom stool," said Saha. Stem cells in cancer scare (Go To Top) London: A new study has revealed that embryonic stem cells that are cultured in the lab accumulate an alarming array of genetic changes, including mutations known to be linked to cancer. The finding poses a question whether such cells could eventually be used for therapy, unless they can be kept fresh and checked for mutations before use. Researchers think that stem cells, which can be programmed to grow into any kind of cell, could one day be used to regenerate or replace cells and organs damaged by disease. But growing these cells has proven problematic. Any cell containing such foreign proteins would presumably trigger a damaging immune response if transplanted into a human patient. Researchers realized they would have to grow their cells differently in order to use them for therapy. Now
another difficulty has come to light. The longer the cells are kept, and
the more they divide, the more errors they build up in their genetic code.
"These mutations we are finding are a much bigger problem," Aravinda Chakravarti
of the Johns Hopkins University in Baltimore, Maryland, was quoted by
Nature, as saying All DNA tends to accumulate mutations as it divides,
because each step in the copying process can introduce errors. But previous,
smaller studies of stem cells had not found problematic levels of mutations.
Stem-cell expert Roger Pedersen of the University of Cambridge, UK, says
he takes a "glass half full" view of the findings, because the billions
of archived cells seemed normal. This shows that the replications needed
to boost stem-cell numbers to usable levels do not necessarily cause problems.
Pedersen adds that the study supports the idea that more, fresh stem-cell
lines would be useful for the scientific community: US federal research
currently relies on a very limited number of lines. High vitamin E doses improve life span (Go To Top) Washington: A new study has revealed that high doses of vitamin E improves life span and neurological performance in mice. Their just-published paper shows that using vitamin E supplementation physiologically comparable to recent human experiments in Alzheimer's Disease patients, resulted in these major findings: Male mice showed a 40 percent increase in median lifespan (to 85 1 4 weeks from 61 1 4). Increases in the ability to perform tests measuring neuromuscular performance (high-wire tightrope) and cognitive exploratory activity (T-maze); the increases on both tests ranged 9 pecent to 24 percent at 52 weeks, and 28 percent to 45 percent at 78 weeks of age. The paper "Vitamin E at high doses improves survival, neurological performance and brain mitochondrial function in aging male mice" appears online in the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, published by the American Physiological Society. Research was by Ana Navarro, Carmen Gomez, Maria-Jesus Sanchez- Pino, Hipolito Gonzalez and Manuel J. Bandez of the University of Cadiz, Spain, and Alejandro D. Boveris and Alberto Boveris of the University of Buenos Aires. Results seen supporting 'free radical' theory of aging Alberto Boveris, professor at the University of Buenos Aires, said the results of these extended experiments "are in line with the free radical theory of aging put forward by Gerschman and Harman in the 1950s. Our results show a significant negative correlation between the mitochondrial content of the oxidation products of free-radical mediated reactions and mitochondrial enzymatic activities. "Moreover,
brain mitochondrial enzymatic activities were linearly related to mice
success in the tests of neuromuscular function and of exploratory and
cognitive activity and to the maximal mice life span," Boveris reported.
He noted that the amount of vitamin E supplementation was metabolically
and physiologically similar to the 1200-2000mg. daily dosage for two to
three years used in two Alzheimer's Disease experiments involving over
400 patients without adverse effects. The paper observes that the "study
shows the beneficial effects of high doses of vitamin E on the median
and maximal lifespan of male mice, an effect that is parallel to a beneficial
effect on the decline of neurological performance and mitochondrial function
associated with aging." It said the "marked increase" in median lifespan
and the moderate rise of maximal lifespan "is properly described as a
delay in the onset of the almost linear decay in mice survival." References: India Travel Times, News, Hotels, Airlines, Indian, Tourism, Tourist, Tour, Ayurveda, Yoga, Hotel |
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