News 22 juni 2009
Antibiotics Take Toll on Beneficial
Microbes in Gut
It’s common knowledge that a protective navy of bacteria normally floats in our
intestinal tracts. Antibiotics at least temporarily disturb the normal balance. But
it’s unclear which antibiotics are the most disruptive, and if the full array of
“good bacteria” return promptly or remain altered for some time. In studies in
mice, University of Michigan scientists have shown for the first time that two different
types of antibiotics can cause moderate to wide-ranging changes in the ranks of these
helpful guardians in the gut. In the case of one of the antibiotics, the armada of
“good bacteria” did not recover its former diversity even many weeks after a
course of antibiotics was over. The findings could eventually lead to better choices of
antibiotics to minimize side effects of diarrhea, especially in vulnerable patients. They
could also aid in understanding and treating inflammatory bowel disease, which affects an
estimated 500,000 to 1 million Americans, and Clostridium difficile, a growing and serious
infection problem for hospitals. Normally, a set of thousands of different kinds of
microbes lives in the gut – a distinctive mix for each person, and thought to be
passed on from mother to baby. The microbes, including many different bacteria, aid
digestion and nutrition, appear to help maintain a healthy immune system, and keep order
when harmful microbes invade. “Biodiversity is a well-known concept in the health of
the world’s continents and oceans. Diversity is probably important in the gut
microsystem as well,” says Vincent B. Young, M.D., Ph.D., senior author of the study,
which appears in the June issue of Infection and Immunity. The study results suggest that
unless medical research discovers how to protect or revitalize the gut microbial
community, “we may be doing long-term damage to our close friends,” says Young,
assistant professor in the departments of internal medicine and microbiology and
immunology at the U-M Medical School.
Bicycle helmet laws key to kids
wearing helmets
Studies have shown wearing a helmet while riding a bicycle reduces one’s risk of
death by more than 50 percent, yet every three days, a child in the United States is
killed while riding a bicycle, and every day at least 100 children are treated in
emergency rooms due to bicycle-related head injuries. A report released today by the
University of Michigan C.S. Mott Children’s Hospital National Poll on Children’s
Health reveals that in areas where no bicycle helmet laws exist, nearly one-half of
children, ages 4 – 17, never wear a helmet. “These statistics underscore the
importance of helmet laws to help prevent death and injury from children not wearing
helmets while riding their bikes,” says Matthew M. Davis, M.D., director of the
National Poll on Children’s Health. “Yet only twenty one states have helmet use
laws for children.”
Sleep treatments improve fatigue
and tiredness
It may seem like common sense, but a good night’s sleep could be the answer to
getting energy back, according to a study at the University of Michigan Sleep Disorders
Center. Patients with complaints of fatigue, tiredness or lack of energy improved with
nightly use of continuous positive airway pressure (CPAP) or related devices that are
often prescribed for those with obstructive sleep apnea, according to the study published
in this week’s issue of the Journal of Clinical Sleep Medicine. “Many physicians
and patients assume that while complaints of daytime sleepiness may indicate a sleep
disorder, complaints of fatigue, tiredness or lack of energy must be caused by some other
medical or psychiatric problem,” says senior author Ronald D. Chervin, M.D., M.S.,
Director of the U-M Sleep Disorders Center and Michael S. Aldrich Collegiate Professor of
Sleep Medicine in the Department of Neurology at the U-M Medical School.
Fewer Injuries to Mothers and
Newborns During Childbirth but More Could be Prevented
Injuries to mothers during childbirth decreased significantly between 2000 and 2006,
according to the latest news and numbers from the Agency for Healthcare Research and
Quality. The number of mothers who experienced injuries while giving birth vaginally
without the use of forceps or other instruments dropped by 30 percent. For mothers giving
birth vaginally with the use of instruments and by cesarean section, injuries declined
about 20 percent. Despite the declines, nearly 158,000 potentially preventable injuries
occurred to mothers and infants during childbirth in U.S. hospitals in 2006.
No Proof Found That Genetic Testing
Helps Prevent Blood Clots
According to a new report by the Department of Health & Human Services' (HHS) Agency
for Healthcare Research and Quality (AHRQ), there is insufficient evidence to conclude
that genetic testing for two gene mutations in adults with a history of blood clots helps
to prevent a condition known as deep-vein thrombosis or to improve other clinical
outcomes. The report, a summary of which will be published in the June 17 issue of JAMA,
also failed to find any benefit from genetic testing of family members of patients who
have at least one of the two mutations—known as Factor V Leiden (FVL) and prothrombin
G20210A—as well as a history of deep-vein thrombosis. As many as 600,000 Americans
each year may have deep-vein thrombosis—blood clots that form in the legs or pelvis.
The condition occurs most commonly in people who are sedentary for a long period of time,
such as when recovering from surgery or traveling long distances. The true number of
people who develop a pulmonary embolism is unknown, but AHRQ data for hospital patients
show that 258,000 individuals were diagnosed with the condition in 2006, and 20,000 died
as a result. "While genetic testing shows great promise to improve treatment and
prevent disease, this report clearly shows that we need more research and evidence to
achieve its full potential," said AHRQ Director Carolyn M. Clancy, M.D. "But
people can help reduce their likelihood of developing a blood clot by talking with their
doctor about precautions." The evidence report was requested and supported by the
Office of Public Health Genomics (OPHG) at HHS' Centers for Disease Control and
Prevention. The Evaluation of Genomic Applications in Practice and Prevention (EGAPP)
Working Group, established by OPHG in 2005, will use this evidence report and other
evidence to make recommendations on the validity and utility of genetic tests for FVL and
prothrombin G20210A. This report, titled Outcomes of Genetic Testing in Adults with a
History of Venous Thromboembolism, is the fifth evidence report requested for EGAPP.
Researchers Conduct Unique Studies
on Childhood Obesity
University of Saskatchewan (U of S) researchers are delving deeper into reasons behind
childhood obesity thanks to $665,000 in grants provided through a partnership involving
the Canadian Institutes of Health Research (CIHR), Rx&D Health Research Foundation and
the Heart and Stroke Foundation of Canada. Childhood obesity is a growing concern in North
America and worldwide. Only 21 per cent of Canadian youth meet international guidelines
for physical activity. Should current trends continue, Canada will have a generation of
children growing up with poorer health status than their parents. “We need to address
childhood obesity and other chronic diseases that are taking a toll on the health care
system and on rising costs associated with a sedentary, overweight Canadian
population,” said Karen Chad, U of S Acting Vice-President Research, who is also a
physical activity researcher. “This funding will help our outstanding researchers
better understand childhood obesity and the real reasons behind it.” Today the CIHR
announced $1.9 million for five separate Canadian projects that aim to better understand
eating and exercise behaviours and explore new ways children can avoid obesity or control
it.
The fight against dangerous
chemicals
Chemicals are present in practically everything that we surround ourselves with. We cannot
do without chemicals in modern life, but some chemicals have harmful effects on humans and
on the environment. The Danish EPA assesses chemicals and is involved in laying down the
rules for how they may be used. Lip salves, clothes, computers, cleaning agents, and
teething rings for babies are examples of products containing chemical substances. There
are around 100,000 chemical substances on the EU market and an estimated 20,000 on the
Danish market. The substances serve important functions in products, but some of them are
dangerous, while we are ignorant of the effect of others on humans and the environment.
The Danish EPA is responsible for managing a great number of rules on chemicals. These
rules have been established to avoid health hazards and damage to the environment when the
substances are manufactured, stored, and used. The Danish EPA Chemical Inspection Service
supervises compliance with the legislation. The Danish EPA continually assesses the risk
associated with a number of substances whose effects we are not yet familiar with. This
work is carried out in collaboration with other EU Member States. Any new knowledge is
used, for example, to establish new EU regulation of the quantities of a substance allowed
in certain products. Some substances are so dangerous that they may not be used for
certain purposes. This applies e.g. to lead and substances which deplete the ozone layer.
Other dangerous substances must be labelled by the manufacturer or importer, so that the
consumer can read how the product is to be used safely. These substances and their
labelling requirements are included in the EU list of dangerous substances, which contains
about 8,000 substances and substance groups. A number of substances are undesirable
because they have problematic effects and are used in very large quantities. According to
the Danish EPA's assessment, these substances should be avoided as far as possible and we
have therefore prepared a list of undesirable substances and substance groups. The list is
meant as a guideline which manufacturers, product developers, procurement departments, and
other players can use as part of their efforts to substitute the problematic substances
with less problematic ones.
Johns Hopkins researchers are
investigating a troubling potential source of resistant pathogens - the American farm.
Ellen Silbergeld, Eng '72 (PhD), recalls that she did not want to go to the seminar. She
was a professor of epidemiology at the University of Maryland School of Medicine in 1999
when her department's chairman needed an audience for the seminar's presenter, a candidate
for a faculty position. Silbergeld recalls the chairman saying, "Please, just sit in
the room. You can come to lunch." So she sat in the room, and something caught her
attention. The seminar was on hospital-acquired infections, but the presenter mentioned in
passing that some drug-resistant infections came from food. That seemed odd. Silbergeld
knew you could pick up Salmonella from, say, tainted chicken salad. But how would that
Salmonella have become resistant to antibiotics? She turned to a colleague and asked.
Because, he said, factory chicken farms routinely feed antibiotics to their flocks, to
accelerate growth, and the drugs generate resistance.
UGA researchers achieve
breakthrough in effort to develop tiny biological fuel cells
University of Georgia researchers have developed a successful way to grow molecular wire
brushes that conduct electrical charges, a first step in developing biological fuel cells
that could power pacemakers, cochlear implants and prosthetic limbs. The journal Chemical
Science calls the technique "a significant breakthrough for nanotechnology." UGA
chemist Jason Locklin and graduate students Nicholas Marshall and Kyle Sontag grew polymer
brushes, made up of chains of thiophene and benzene, aromatic molecules sometimes used as
solvents, attached to metal surfaces as ultra-thin films. "The molecular wires are
actually polymer chains that have been grown from a metal surface at very high
density," said Locklin, who has a joint appointment in UGA's Franklin College of Arts
and Science and on the Faculty of Engineering. "The structure of the film resembles a
toothbrush, where the chains of conjugated polymers are like the bristles. We call these
types of coatings polymer brushes. To get chains to pack tightly in extended
conformations, they must be grown from the surface, a method we call the 'grafting from'
approach." Using this approach, the scientists laid down a single layer of thiophene
as the film's initial coating, then built up chains of thiophene or benzene using a
controlled polymerization technique. Their research, funded by the Petroleum Research
Foundation, was published in the June issue of the journal, Chemical Communications.
"The beauty of organic semiconductors is how their properties change, based on size
and the number of repeating units," said Locklin, who is a member of UGA's Nanoscale
Science and Engineering Center. Thiophene itself is an insulator, said Locklin, "but
by linking many thiophene molecules together in a controlled fashion, the polymers have
conducting properties." More importantly, he said, "this technique gives us the
control to systematically vary polymer architecture, opening up the possibility for
various uses in electronic devices such as sensors, transistors and diodes." The
ultra-thin films are between 5 and 50 nanometers—too small to see, even under a
high-powered optical microscope.
Three to six months to lose weight
gained in pregnancy is normal
Once the baby arrives, many new mothers want to return to their former weight quickly
– just like film stars who appear in the media in bikinis just weeks after giving
birth. But according to the German Institute for Quality and Efficiency in Health Care
(IQWiG), women should not put themselves under too much pressure straight away. In
information published today on Informed Health Online, the Institute also warns that
overdoing early weight loss attempts could have a negative impact on breastfeeding.
Antibiotics take toll on beneficial
microbes in gut
It’s common knowledge that a protective navy of bacteria normally floats in our
intestinal tracts. Antibiotics at least temporarily disturb the normal balance. But
it’s unclear which antibiotics are the most disruptive, and if the full array of
“good bacteria” return promptly or remain altered for some time. In studies in
mice, University of Michigan scientists have shown for the first time that two different
types of antibiotics can cause moderate to wide-ranging changes in the ranks of these
helpful guardians in the gut. In the case of one of the antibiotics, the armada of
“good bacteria” did not recover its former diversity even many weeks after a
course of antibiotics was over.
Cancer-Causing Protein Can Also
Help Fight the Tumors It Causes
Oncogenes are genes that when mutated or expressed in high concentrations can cause normal
cells to become cancerous. Now research from Tel Aviv University is demonstrating that
Ras, one of the first oncogenes discovered, has the power to heal as well as harm. Ph.D.
student Oded Rechavi and his fellow researchers at Tel Aviv University's Department of
Neurobiology have found that Ras has the ability to transfer from cancer cells into immune
cells — such as t-cells — a transfer that may be the key to creating new drugs
to fight cancerous tumors.
Cerebrospinal fluid shows
Alzheimer¿s disease deterioration much earlier
It is possible to determine which patients run a high risk of developing Alzheimer’s
disease and the dementia associated with it, even in patients with minimal memory
impairment. This has been shown by recent research at the Sahlgrenska Academy.The results
have been published in the most recent issue of the prestigious medical journal Lancet
Neurology. "The earlier we can catch Alzheimer’s disease, the more we can do for
the patient. The disease is one that progresses slowly, and the pharmaceuticals that are
currently available are only able to alleviate the symptoms", says Kaj Blennow,
professor at the Sahlgrenska Academy, and a world?leading researcher in the field.
Study finds that tobacco companies
changed design of cigarettes without alerting smokers
As President Obama prepares to sign a bill giving the Food and Drug Administration (FDA)
oversight of the tobacco industry, a new study from Harvard School of Public Health (HSPH)
researchers shows that tobacco manufacturers have continually changed the ingredients and
the design of their cigarettes over time, even if those changes have exceeded acceptable
product variance guidelines. The result, say the researchers, is that consumers who buy
the same brand of product are not made aware of how that product has been altered and what
effect those alterations might have on their levels of addiction or harm. "I hope the
FDA requires disclosure of any changes made to tobacco products and that the changes are
disallowed if shown to increase appeal, addiction and harm," said Greg Connolly,
director of the Tobacco Control Research Program at HSPH. The study appears in the
"Online First" section of the Journal of Tobacco Control and will appear in an
upcoming print issue of the journal. For their study, Connolly and lead author Geoffrey
Ferris Wayne, an HSPH researcher, studied internal tobacco company documents released
following the 1998 Master Settlement Agreement. These documents describe significant
changes made to commercial products over time, including blend, processing, casing,
flavoring and physical design features. For example, new methods were developed to process
tobacco, altering the smoke chemistry and the form of nicotine delivery, and the levels of
processed tobaccos were regularly adjusted within brands. Despite the constant innovation
of tobacco products, which in many cases have exceeded the levels of acceptable variance
established within the tobacco industry, for the most part, these changes were not
disclosed to consumers, say the researchers. "Even incremental changes that occur
over a period of years can result in significant design differences. The resulting product
may have altered chemistry or delivery, yet the smoker is largely unaware of these
changes. This underscores the need for industry transparency and accountability,"
said Ferris Wayne.
Green tea may affect prostate
cancer progression
According to results of a study published in Cancer Prevention Research, a journal of the
American Association for Cancer Research, men with prostate cancer who consumed the active
compounds in green tea demonstrated a significant reduction in serum markers predictive of
prostate cancer progression. "The investigational agent used in the trial, Polyphenon
E (provided by Polyphenon Pharma) may have the potential to lower the incidence and slow
the progression of prostate cancer," said James A. Cardelli, Ph.D., professor and
director of basic and translational research in the Feist-Weiller Cancer Center, LSU
Health Sciences Center-Shreveport. Green tea is the second most popular drink in the
world, and some epidemiological studies have shown health benefits with green tea,
including a reduced incidence of prostate cancer, according to Cardelli. However, some
human trials have found contradictory results. The few trials conducted to date have
evaluated the clinical efficacy of green tea consumption and few studies have evaluated
the change in biomarkers, which might predict disease progression. Cardelli and colleagues
conducted this open-label, single-arm, phase II clinical trial to determine the effects of
short-term supplementation with green tea's active compounds on serum biomarkers in
patients with prostate cancer. The biomarkers include hepatocyte growth factor (HGF),
vascular endothelial growth factor (VEGF) and prostate specific antigen (PSA). HGF and
VEGF are good prognostic indicators of metastatic disease. The study included 26 men, aged
41 to 72 years, diagnosed with prostate cancer and scheduled for radical prostatectomy.
Patients consumed four capsules containing Polyphenon E until the day before surgery
— four capsules are equivalent to about 12 cups of normally brewed concentrated green
tea, according to Cardelli. The time of study for 25 of the 26 patients ranged from 12
days to 73 days, with a median time of 34.5 days. Findings showed a significant reduction
in serum levels of HGF, VEGF and PSA after treatment, with some patients demonstrating
reductions in levels of greater than 30 percent, according to the researchers.
Omega-3 fatty acids appear to
impact AMD progression
Omega-3 fatty acids found in fatty fish such as tuna and salmon may protect against
progression of age-related macular degeneration (AMD), but the benefits appear to depend
on the stage of disease and whether certain supplements are taken, report researchers at
the Laboratory for Nutrition and Vision Research (LNVR), Jean Mayer USDA Human Nutrition
Research Center on Aging (HNRCA) at Tufts University. The researchers calculated intakes
of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) from dietary questionnaires
administered to 2,924 men and women, aged 55 to 80 years, participating in an eight-year
supplement trial, the Age-Related Eye Disease Study (AREDS) of the National Eye Institute
(NEI). The AREDS trial results suggest taking supplements of antioxidants plus zinc
prevents progression of late-stage AMD. AREDS study participants were randomly allocated
to receive either a placebo or supplements containing the antioxidants vitamins C and E
and beta carotene, the minerals zinc and copper, or a combination of both. "In our
study, we observed participants with early stages of AMD in the placebo group benefited
from higher intake of DHA, but it appears that the high-dose supplements of the
antioxidants and/or the minerals somehow interfered with the benefits of DHA against early
AMD progression," says senior author Allen Taylor, PhD, director of the LNVR at the
USDA HNRCA. Taylor is also a professor at the Friedman School of Nutrition Science and
Policy at Tufts and Tufts University School of Medicine (TUSM). The antioxidant
supplements did not seem to interfere with the protective effects of DHA and EPA against
progression to advanced stages of AMD. Participants who consumed higher amounts of DHA and
EPA appeared to have lower risk of progression to both wet and dry forms of advanced AMD.
The results are published on-line ahead of print in the British Journal of Ophthalmology.
"Data from the present study also shows the supplements and omega-3 fatty acids
collaborate with low-dietary glycemic index (dGI) diets against progression to advanced
AMD," says corresponding author Chung-Jung Chiu, DDS, PhD, a scientist in the LNVR
and an assistant professor at TUSM. "Our previous research suggests a low-GI diet may
prevent AMD from progressing to the advanced stage. We hypothesize that the rapid rise of
blood glucose initiated by high-GI foods results in cellular damage that retinal cells
cannot handle, thus damaging eye tissues." dGI is a scale used to determine how
quickly carbohydrates are broken down into blood sugar, also known as blood glucose. Foods
such as sweetened drinks, sodas and white bread are high-GI because they trigger a sharp
rise and fall of blood sugar. Low-GI foods, such as whole grain versions of pasta and
bread, have a milder effect on blood sugar response. Earlier data published by Taylor and
Chiu suggests that daily substitution of five slices of whole grain bread for white bread
out of a total intake of 250 g of carbohydrate might cut out almost 8% of advanced AMD
over five years. This is readily achievable with little diet behavior modification.
Could older population have enough
exposure to past H1N1 flu strains to avoid infection?
A letter to the editor by Rhode Island Hospital infectious diseases specialist Leonard
Mermel, DO, identifies characteristics of the outbreak of H1N1 in 1977 and speculates its
impact on this pandemic. His letter is published in the June 20 edition of the journal the
Lancet 2009 (vol 373 p2108-09).Mermel notes that in the late 1970s, an influenza H1N1
reappeared in humans. It had a pandemic-like spread that began in younger aged
individuals. This strain, known as the "Russian flu" H1N1, was similar to H1N1
strains that circulated internationally between 1946 and 1957. The Russian flu spread
rapidly across the former Soviet Union, initially affecting individuals between the ages
of 14 and 20 in schools, as well as young military personnel, and later spread to
preschool children. Individuals older than age 30, however, had dramatically lower attack
rates and the overall mortality was low. The epidemic peaked rapidly, with a relatively
short duration. In the United States, the first outbreak of the Russian flu occurred in a
Wyoming high school. The attack rate there was over 70 percent, however, it affected
students only; no faculty were reported to have the illness. High attack rates were seen
in schools as well as military bases throughout the United States, similar to the outbreak
in Russia. There were few reports of the H1N1 strain in individuals older than age 26, and
again, the mortality rate was low. In his commentary, Mermel hypothesizes that the H1N1
strain circulating now may have enough similarity to the previously circulating H1N1
strains or the H1N1 used in past vaccines so that it may lead to protection of older
individuals. He concludes by noting that the weeks ahead should help us to determine if
this will be the case.
Study highlights massive imbalances
in global fertilizer use
Synthetic fertilizers have dramatically increased food production worldwide. But the
unintended costs to the environment and human health have been substantial. Nitrogen
runoff from farms has contaminated surface and groundwater and helped create massive
"dead zones" in coastal areas, such as the Gulf of Mexico. And ammonia from
fertilized cropland has become a major source of air pollution, while emissions of nitrous
oxide form a potent greenhouse gas.These and other negative environmental impacts have led
some researchers and policymakers to call for reductions in the use of synthetic
fertilizers. But in a report published in the June 19 issue of the journal Science, an
international team of ecologists and agricultural experts warns against a
"one-size-fits-all" approach to managing global food production. "Most
agricultural systems follow a trajectory from too little in the way of added nutrients to
too much, and both extremes have substantial human and environmental costs," said
lead author Peter Vitousek, a professor of biology at Stanford University and senior
fellow at Stanford's Woods Institute for the Environment. "Some parts of the world,
including much of China, use far too much fertilizer," Vitousek said. "But in
sub-Saharan Africa, where 250 million people remain chronically malnourished, nitrogen,
phosphorus and other nutrient inputs are inadequate to maintain soil fertility."
New supplement may help slow sight
loss in elderly
Queen's University Belfast academics have helped develop an antioxidant supplement which
may slow down sight loss in elderly people. The supplement may help those affected by the
leading cause of blindness in the Western World, a five-year research programme has found.
Professor Usha Chakravarthy, from Queen’s Centre of Vision and Vascular Science
(CVVS), co-ordinated the study, which looked at nutritional supplements for patients with
early age-related macular (AMD) degeneration and found they helped sharpen vision. Details
of the findings are being presented in Belfast today (Friday) by Professor Chakravarthy
and Dr Stephen Beatty, Head of Vision Research at Waterford Institute of Technology.
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