CHANNAI, India (Reuters Health) Dec 28 - Yoga induces a feeling of well-being in healthy people, and can reverse the clinical and biochemical changes associated with metabolic syndrome, according to results of studies from Sweden and India.
Dr. R.P. Agrawal, of the SP Medical College, Bikaner, India, and colleagues evaluated the beneficial effects of yoga and meditation in 101 adults with features of metabolic syndrome. In their randomized study, 55 subjects were assigned to 3 months of regular daily yoga, including standard postures, and Raja Yoga, a form of transcendental meditation, while the remaining received standard care.
Waist circumference, systolic blood pressure, fasting blood sugar, and triglycerides were significantly lower, and high density lipoprotein levels were higher in the yoga group as compared to controls, Dr. Agrawal's team reports in the December issue of Diabetes Research and Clinical Practice.
"Yoga and meditation have always been an essential part of life in the traditional system of treatment," Dr. R.P Agrawal and colleagues write. They attribute the effects to the redistribution of body fat, decreased arterial tone and peripheral resistance due to parasympathetic predominance, and increased sensitivity of beta cells of the pancreas.
In the second report, published on December 19 in BioMed Central Complementary and Alternative Medicine, Dr. Anette Kjellgren from the University of Karlstad, Sweden and her team evaluated the beneficial effects of yogic breathing exercises on healthy volunteers.
Fifty-five adults were advised to practice "Sudarshan Kriya," which involves cycles of slow normal and rapid breathing exercises. The exercises were practiced for an hour daily, six days a week for six weeks, while 48 controls were advised to relax in an armchair for 15 minutes daily.
At the end of the study period, feelings of anxiety, stress and depression were significantly decreased, and optimism was significantly increased, in the yoga group compared to controls, Dr. Kjellgren and colleagues report.
Yoga induces a "relaxation response" associated with reduced sympathetic nervous system activity and a feeling of well-being probably due to an increase in antioxidants and lower levels of cortisol, Dr. Kjellgren's team suggests.
Yoga not only helps in prevention of lifestyle diseases, but can also be "a powerful adjunct therapy when these diseases arise," co-author Dr. Faahri Saatiglou, from the University of Oslo, told Reuters Health. "We do not emphasize this point enough in our Western health care."
Sunday, December 30, 2007
New Findings About Dangerous Cancer Protein
new report from the University of Pennsylvania and Johns Hopkins University finds the Myc protein can stop the production of at least 13 microsRNAs – small pieces of nucleic acid that help control which genes are turned on and off.
The study also finds in several cases, re-introducing repressed miRNAs into Myc-containing cancer cells suppressed tumor growth in mice – this means it is possible that a gene-therapy approach could be effective in treating some cancers.
Researchers analyzed more than 300 miRNAs in lymphoma cells of humans and mice. They had previously found Myc could turn on one particular group of growth-promoting miRNAs in lymphoma cells. In the cells with high amounts of Myc protein, researchers found big changes in the quantities of at least 13 miRNAs.
When researchers took a closer look at the DNA of the lymphoma cells, they found Myc was directly attaching to the DNA at the miRNA genes.
“This study expands our understanding of how Myc acts as such a potent cancer-promoting protein,” lead researcher Joshua Mendell, Johns Hopkins University, was quoted as saying. “We already knew that it can directly regulate thousands of genes. Through its repertoire of miRNAs, Myc likely influences the expression of thousands of additional genes. Activation of Myc therefore profoundly changes the program of genes that are expressed in cancer cells.”
Researchers also reintroduced several repressed miRNAs into mouse lymphomas with high levels of Myc. When they measured the effect on the progression of lymphoma they found at least five of the miRNAs could stop cancer from growing.
Mendell says RNA-based therapies have had some success in animals and it is possible to find a wide range of miRNAs that can stop cancers in their tracks.
The study also finds in several cases, re-introducing repressed miRNAs into Myc-containing cancer cells suppressed tumor growth in mice – this means it is possible that a gene-therapy approach could be effective in treating some cancers.
Researchers analyzed more than 300 miRNAs in lymphoma cells of humans and mice. They had previously found Myc could turn on one particular group of growth-promoting miRNAs in lymphoma cells. In the cells with high amounts of Myc protein, researchers found big changes in the quantities of at least 13 miRNAs.
When researchers took a closer look at the DNA of the lymphoma cells, they found Myc was directly attaching to the DNA at the miRNA genes.
“This study expands our understanding of how Myc acts as such a potent cancer-promoting protein,” lead researcher Joshua Mendell, Johns Hopkins University, was quoted as saying. “We already knew that it can directly regulate thousands of genes. Through its repertoire of miRNAs, Myc likely influences the expression of thousands of additional genes. Activation of Myc therefore profoundly changes the program of genes that are expressed in cancer cells.”
Researchers also reintroduced several repressed miRNAs into mouse lymphomas with high levels of Myc. When they measured the effect on the progression of lymphoma they found at least five of the miRNAs could stop cancer from growing.
Mendell says RNA-based therapies have had some success in animals and it is possible to find a wide range of miRNAs that can stop cancers in their tracks.
Tuesday, December 18, 2007
Cardiovascular Disease Update
Cardiovascular disease (CVD) death rates are declining, but CVD is still the No. 1 cause of death in the United States, and risk factor control remains a challenge for many, according to the most recent data available online from the American Heart Association's Heart Disease and Stroke Statistics - 2008 Update.
Monday, December 17, 2007
Climate Change Preparedness
Climate change refers to any significant change in measures of climate, such as temperature, precipitation, or wind, that lasts for decades or longer.
Potential effects of climate change are likely to include more variable weather, heat waves, heavy precipitation events, flooding, droughts, intense storms such as hurricanes, rises in sea level, and air pollution.
Experts at the Centers for Disease Control and Prevention cannot predict how these changes will affect society and public health, but are preparing for the resulting health issues (podcast) that may be associated with global climate change.
Potential effects of climate change are likely to include more variable weather, heat waves, heavy precipitation events, flooding, droughts, intense storms such as hurricanes, rises in sea level, and air pollution.
Experts at the Centers for Disease Control and Prevention cannot predict how these changes will affect society and public health, but are preparing for the resulting health issues (podcast) that may be associated with global climate change.
Thursday, December 13, 2007
Hypertension Linked to Dementia
Elderly people with high blood pressure may be more likely to develop thinking and learning problems that can lead to dementia.
Hypertension was linked to one of two types of mild cognitive impairment, a condition that can foreshadow the development of dementia, but not the type strongly associated with Alzheimer's disease, according to the study published in the journal Archives of Neurology.
Hypertension was linked to one of two types of mild cognitive impairment, a condition that can foreshadow the development of dementia, but not the type strongly associated with Alzheimer's disease, according to the study published in the journal Archives of Neurology.
Wednesday, December 12, 2007
London to host ambitious research hub
The announcement last week that Europe's largest medical-research facility is to be built in central London has been largely welcomed by Britain's biomedical community, which hopes that the centre will accelerate the translational research — so beloved by policy-makers — that brings discoveries from the lab to patients. But the process has ruffled a few scientists' feathers.
Prime Minister Gordon Brown says that the government will sell a plot of land between the British Library and the international train station at St Pancras to a consortium of the Medical Research Council (MRC), Cancer Research UK (CRUK), the Wellcome Trust and University College London, for £85 million (US$173 million). The total cost of the UK Centre for Medical Research and Innovation, including purchase of the land, is pegged at more than £500 million. The MRC and CRUK are expected to shoulder the bulk of the cost, and the Wellcome Trust has committed £100 million to the project. The centre, which is expected to open in 2013, will employ up to 1,500 researchers and support staff.
It aims to compete with other global multidisciplinary scientific-research collaborations such as Biopolis in Singapore, the Allston Initiative at Harvard University and the Science-based Zizhu Industrial Park in Shanghai. “Being in central London, right alongside main teaching hospitals and main offices for clinical research, is a much better location for translational research,” MRC head Leszek Borysiewicz told Nature. “There is every opportunity for scientists to translate their work with the most appropriate clinical partners when they are that close to each other.”
Details of the research projects and teams that will be transferred to the centre remain scarce. Nobel laureate Paul Nurse, who is president of Rockefeller University in New York and CRUK's former director, will head an independent science-planning committee to determine the shape and direction of the centre's work and the facilities needed to carry it out.
The project will face numerous hurdles. Some researchers have expressed concerns that the infusion of funding into a prestigious project with limited space could ultimately hamper some basic research already taking place. And choosing to site the centre — which will include the largest animal-research laboratory in Europe and a category-4 virus containment laboratory — next to an international transport hub has sparked biosafety concerns.
Unease about potential staff reductions and shelving of core research has been particularly pronounced at the MRC's largest research body, the National Institute for Medical Research (NIMR), which will account for the bulk of the MRC's contribution to the new centre. The NIMR's 750 scientists and staff have already experienced nearly four years of debate within the MRC over its plans to move the institute from its current 19-hectare site in Mill Hill, northwest London, to central London. An earlier plan to move the institute to a site next to Euston Station in conjunction with University College London was ditched in March after the proposal faced scathing criticism from a key committee in the House of Commons that had held hearings on the plan.
NIMR staffers have previously expressed concerns that the 1.4-hectare site at St Pancras would have insufficient space for the institute's current facilities. Scientists have also criticized MRC executives for poor internal communication over the course of the discussions on the institute's fate, and say that the continuing uncertainty over how much of the NIMR will be transferred to the new research centre is taking a toll on morale. “It's going to be a very difficult management process to keep people happy,” says Robin Lovell-Badge, head of stem-cell biology and developmental genetics at the NIMR. “We are very nervous about it. Of course we can see the advantages and we want to be optimistic, but a lot of people at the institute just don't trust the MRC because of its past history.”
Translational medicine
Borysiewicz says that Nurse's committee is expected to draw up broad outlines of the new centre's scientific mission over the weeks to come, and he adds that NIMR researchers will be represented on the committee. “It may be five or six years before the new site is ready,” he says. “It is the MRC's intention to support the science at the NIMR during that period.”
Others think that the move will help their work. Neil McDonald, a structural biologist at CRUK, notes that his current central London lab needs major refurbishment, and says that the new centre was being viewed positively by CRUK's several hundred researchers. “The advantage of a big research institute, and the synergies involved, are not just economies of scale but accessibility to facilities that you wouldn't be able to afford at a smaller institute,” he says. “If you are in the same building and you see people in the canteen every day, it promotes collaborations and interactions, not just between research scientists but between scientists and clinicians.”
The proposed centre still needs planning permission to go ahead, but with Brown's backing, it is likely to succeed.
It aims to compete with other global multidisciplinary scientific-research collaborations such as Biopolis in Singapore, the Allston Initiative at Harvard University and the Science-based Zizhu Industrial Park in Shanghai. “Being in central London, right alongside main teaching hospitals and main offices for clinical research, is a much better location for translational research,” MRC head Leszek Borysiewicz told Nature. “There is every opportunity for scientists to translate their work with the most appropriate clinical partners when they are that close to each other.”
Details of the research projects and teams that will be transferred to the centre remain scarce. Nobel laureate Paul Nurse, who is president of Rockefeller University in New York and CRUK's former director, will head an independent science-planning committee to determine the shape and direction of the centre's work and the facilities needed to carry it out.
The project will face numerous hurdles. Some researchers have expressed concerns that the infusion of funding into a prestigious project with limited space could ultimately hamper some basic research already taking place. And choosing to site the centre — which will include the largest animal-research laboratory in Europe and a category-4 virus containment laboratory — next to an international transport hub has sparked biosafety concerns.
Unease about potential staff reductions and shelving of core research has been particularly pronounced at the MRC's largest research body, the National Institute for Medical Research (NIMR), which will account for the bulk of the MRC's contribution to the new centre. The NIMR's 750 scientists and staff have already experienced nearly four years of debate within the MRC over its plans to move the institute from its current 19-hectare site in Mill Hill, northwest London, to central London. An earlier plan to move the institute to a site next to Euston Station in conjunction with University College London was ditched in March after the proposal faced scathing criticism from a key committee in the House of Commons that had held hearings on the plan.
NIMR staffers have previously expressed concerns that the 1.4-hectare site at St Pancras would have insufficient space for the institute's current facilities. Scientists have also criticized MRC executives for poor internal communication over the course of the discussions on the institute's fate, and say that the continuing uncertainty over how much of the NIMR will be transferred to the new research centre is taking a toll on morale. “It's going to be a very difficult management process to keep people happy,” says Robin Lovell-Badge, head of stem-cell biology and developmental genetics at the NIMR. “We are very nervous about it. Of course we can see the advantages and we want to be optimistic, but a lot of people at the institute just don't trust the MRC because of its past history.”
Translational medicine
Borysiewicz says that Nurse's committee is expected to draw up broad outlines of the new centre's scientific mission over the weeks to come, and he adds that NIMR researchers will be represented on the committee. “It may be five or six years before the new site is ready,” he says. “It is the MRC's intention to support the science at the NIMR during that period.”
Others think that the move will help their work. Neil McDonald, a structural biologist at CRUK, notes that his current central London lab needs major refurbishment, and says that the new centre was being viewed positively by CRUK's several hundred researchers. “The advantage of a big research institute, and the synergies involved, are not just economies of scale but accessibility to facilities that you wouldn't be able to afford at a smaller institute,” he says. “If you are in the same building and you see people in the canteen every day, it promotes collaborations and interactions, not just between research scientists but between scientists and clinicians.”
The proposed centre still needs planning permission to go ahead, but with Brown's backing, it is likely to succeed.
Nuclear-reactor closure hits cancer tests
Hospitals across North America have been forced to cancel tests for cancer and heart disease because the unexpected closure of a Canadian nuclear reactor has led to a sudden shortage of medical isotopes.
The 50-year-old National Research Universal (NRU) reactor located in Chalk River, Ontario, was shut down on 18 November for scheduled maintenance and was due back online by mid-December. But Atomic Energy Canada, which owns and operates the facility, extended the outage to install safety-related equipment, including upgrades to the reactor cooling pumps. The reactor supplies about 60% of the molybdenum isotopes used in medical applications globally, including molybdenum-99, which decays into technetium-99m and is used in about 16 million nuclear medicine procedures annually in the United States.
“It's a disaster for patients,” says Sandy McEwan, president of the Society of Nuclear Medicine. North American hospitals now have 20–30% of the medical isotopes they require, he says.
Hospitals use a generator to extract technetium-99m from a source of decaying molybdenum-99. A technetium-99m isotope has a useful life of about one week, but can be stretched to two. MDS Nordion, an Ottawa-based life-sciences firm and molybdenum supplier to Bristol-Myers Squibb Medical Imaging, says it expects shortages of the radioisotope until mid-January. Molybdenum-99 has a half-life of 66 hours and cannot be stockpiled. Reactors in Australia, South Africa and Brussels also produce molybdenum-99. The shortage has reignited a discussion over securing the US supply of medical isotopes by building a reactor in the United States.
The NRU reactor was to be decommissioned in 2005, but its operating licence was extended until problems with two replacement reactors — MAPLE 1 and 2 — could be solved. The two MAPLE reactors and a processing facility were designed to supply the entire global demand for molybdenum-99, iodine-131, iodine-125 and xenon-133. In June, Atomic Energy Canada said that it expected MAPLE 1 and the processing facility to be in service by October 2008, and MAPLE 2 by October 2009.
The 50-year-old National Research Universal (NRU) reactor located in Chalk River, Ontario, was shut down on 18 November for scheduled maintenance and was due back online by mid-December. But Atomic Energy Canada, which owns and operates the facility, extended the outage to install safety-related equipment, including upgrades to the reactor cooling pumps. The reactor supplies about 60% of the molybdenum isotopes used in medical applications globally, including molybdenum-99, which decays into technetium-99m and is used in about 16 million nuclear medicine procedures annually in the United States.
“It's a disaster for patients,” says Sandy McEwan, president of the Society of Nuclear Medicine. North American hospitals now have 20–30% of the medical isotopes they require, he says.
Hospitals use a generator to extract technetium-99m from a source of decaying molybdenum-99. A technetium-99m isotope has a useful life of about one week, but can be stretched to two. MDS Nordion, an Ottawa-based life-sciences firm and molybdenum supplier to Bristol-Myers Squibb Medical Imaging, says it expects shortages of the radioisotope until mid-January. Molybdenum-99 has a half-life of 66 hours and cannot be stockpiled. Reactors in Australia, South Africa and Brussels also produce molybdenum-99. The shortage has reignited a discussion over securing the US supply of medical isotopes by building a reactor in the United States.
The NRU reactor was to be decommissioned in 2005, but its operating licence was extended until problems with two replacement reactors — MAPLE 1 and 2 — could be solved. The two MAPLE reactors and a processing facility were designed to supply the entire global demand for molybdenum-99, iodine-131, iodine-125 and xenon-133. In June, Atomic Energy Canada said that it expected MAPLE 1 and the processing facility to be in service by October 2008, and MAPLE 2 by October 2009.
FDA: Heartburn Drugs Show No Increased Risk For Heart Problems
FDA has completed a comprehensive, scientific review of known safety data for the drugs Prilosec and Nexium.
The FDA concluded that long-term use of these drugs is not likely to be associated with an increased risk of heart problems.
FDA recommends that health care providers continue to prescribe, and patients continue to use, these products as described in the labeling.
The FDA concluded that long-term use of these drugs is not likely to be associated with an increased risk of heart problems.
FDA recommends that health care providers continue to prescribe, and patients continue to use, these products as described in the labeling.
Monday, December 10, 2007
Clinical assessment of infant colour at delivery
Use of video recordings of newborn infants to determine: (1) if clinicians agreed whether infants were pink; and (2) the pulse oximeter oxygen saturation (SpO2) at which infants first looked pink...Among clinicians observing the same videos there was disagreement about whether newborn infants looked pink with wide variation in the SpO2 when they were considered to become pink
"Behind the Counter" Drug Category Proposed
This week's AMNews reports that the Food and Drug Administration is contemplating the establishment of a class of medications that would be available only after counseling from a pharmacist but without a physician's prescription.
While pharmacists tend to be most in favor of this, physicians argue it would make an already fragmented health care system even more so.
They also say the need to see a doctor first is not the most significant barrier to patients getting needed care.
While pharmacists tend to be most in favor of this, physicians argue it would make an already fragmented health care system even more so.
They also say the need to see a doctor first is not the most significant barrier to patients getting needed care.
HIV drug development: the next 25 years
The development of drugs for HIV infection began soon after the virus was discovered 25 years ago. Since then, progress has been substantial, but numerous uncertainties persist about the best way to manage this disease. Here we review the current treatment options, consider novel mechanisms that can be exploited for existing drug targets, and explore the potential of novel targets. With a view to the next quarter century, we consider whether drug resistance can be avoided, which drug classes will be favoured over others, which strategies are most likely to succeed, and the potential impact of pharmacogenomics and individualized therapy.(Charles Flexner)
With health care emerging as a major issue in the 2008 presidential race, NEWSWEEK asked seven Harvard experts to identify specific problems that ought to be addressed, and the steps that should be taken to solve them. The in-depth response to this survey is available on the website and outlines the following topics:
1:Ensure That Every American Has Health Insurance
2:Eliminate Racial Disparities
3:Fix the Medicare Drug Benefit
4:Use Quality-of-Care Report Cards
5:Wire American Medicine
6:Make Sure New Treatments Are Properly Studied
7:Curb Drug Spending Without Hurting Drug Development
1:Ensure That Every American Has Health Insurance
2:Eliminate Racial Disparities
3:Fix the Medicare Drug Benefit
4:Use Quality-of-Care Report Cards
5:Wire American Medicine
6:Make Sure New Treatments Are Properly Studied
7:Curb Drug Spending Without Hurting Drug Development
Bacterial pili, filamentous adhesive structures that extend from the cell surface, are important virulence factors and potential vaccine targets. Pili from Gram-negative bacteria have been structurally characterized. Now
Kang \u003cem\>et al.\u003c/em\>\u003c/b\> (p. \u003ca href\u003d\"http://www.sciencemag.org/cgi/content/short/318/5856/1625\" target\u003d\"_blank\" onclick\u003d\"return top.js.OpenExtLink(window,event,this)\"\>1625\u003c/a\>; \nsee the Perspective by \u003cb\>\u003ca href\u003d\"http://www.sciencemag.org/cgi/content/full/318/5856/1558\" target\u003d\"_blank\" onclick\u003d\"return top.js.OpenExtLink(window,event,this)\"\>Yeates and \nClubb\u003c/a\>\u003c/b\>) describe the structure of the major pilin subunit from a \nGram-positive human pathogen, \u003cem\>Streptococcus pyogenes\u003c/em\>. In the \ncrystal, the subunits associate in columns reminiscent of the likely \narrangement in native pili. The structure also reveals intramolecular \nisopeptide bonds that may stabilize the structure and contribute to \nprotease resistance. This could be a more general mechanism of protein \nstabilization in Gram-positive organisms, which lack the disulfide bond \nformation machinery of Gram-negative bacteria.\u003cp\>\n\u003cfont size\u003d\"-2\"\>CREDIT: KANG \u003cem\>ET \nAL.\u003c/em\>\u003c/font\>\u003c/p\>\u003c/td\>\u003c/tr\>\u003c/table\>\u003c/blockquote\>\n\u003chr\>\n\n\n\n\n\u003cp\>\n\n\n\u003chr\>\n\n\u003ch3\>Dissecting X Inactivation\u003c/h3\>\n\n\u003cp\>\n\n\n\n\n\nOne of the two X chromosomes in mammalian females is randomly inactivated \n\nearly in development to match the single active X chromosome of males. \n\nThis process is regulated through the X-inactivation center (Xic). The two\n\nXics interact in \u003cem\>trans\u003c/em\> at the beginning of X-inactivation, \n\npresumably to allow reciprocal activation/inactivation. So far, single \n\ncopies of elements from the Xic have not been able to recapitulate X \n\ninactivation, suggesting additional elements must be required. \u003cb\>Augui \n\n\u003cem\>et al.\u003c/em\>\u003c/b\> (p. \u003ca href\u003d\"http://www.sciencemag.org/cgi/content/short/318/5856/1632\" target\u003d\"_blank\" onclick\u003d\"return top.js.OpenExtLink(window,event,this)\"\>1632\u003c/a\>)\n\nfind that a region ~200 kilobases upstream of the Xic--the \n\nX-pairing-region (\u003cem\>Xpr\u003c/em\>) --is sufficient in a single copy to allow \n\na transient interaction between the two Xics at a time before the \n\nbeginning of X inactivation. This pairing is cell cycle dependent, can \n\noccur from an ectopic location, and may activate the expression of \n\n",1]
);
//-->
Kang et al. (p. 1625; see the Perspective by Yeates and Clubb) describe the structure of the major pilin subunit from a Gram-positive human pathogen, Streptococcus pyogenes. In the crystal, the subunits associate in columns reminiscent of the likely arrangement in native pili. The structure also reveals intramolecular isopeptide bonds that may stabilize the structure and contribute to protease resistance. This could be a more general mechanism of protein stabilization in Gram-positive organisms, which lack the disulfide bond formation machinery of Gram-negative bacteria.
Kang \u003cem\>et al.\u003c/em\>\u003c/b\> (p. \u003ca href\u003d\"http://www.sciencemag.org/cgi/content/short/318/5856/1625\" target\u003d\"_blank\" onclick\u003d\"return top.js.OpenExtLink(window,event,this)\"\>1625\u003c/a\>; \nsee the Perspective by \u003cb\>\u003ca href\u003d\"http://www.sciencemag.org/cgi/content/full/318/5856/1558\" target\u003d\"_blank\" onclick\u003d\"return top.js.OpenExtLink(window,event,this)\"\>Yeates and \nClubb\u003c/a\>\u003c/b\>) describe the structure of the major pilin subunit from a \nGram-positive human pathogen, \u003cem\>Streptococcus pyogenes\u003c/em\>. In the \ncrystal, the subunits associate in columns reminiscent of the likely \narrangement in native pili. The structure also reveals intramolecular \nisopeptide bonds that may stabilize the structure and contribute to \nprotease resistance. This could be a more general mechanism of protein \nstabilization in Gram-positive organisms, which lack the disulfide bond \nformation machinery of Gram-negative bacteria.\u003cp\>\n\u003cfont size\u003d\"-2\"\>CREDIT: KANG \u003cem\>ET \nAL.\u003c/em\>\u003c/font\>\u003c/p\>\u003c/td\>\u003c/tr\>\u003c/table\>\u003c/blockquote\>\n\u003chr\>\n\n\n\n\n\u003cp\>\n\n\n\u003chr\>\n\n\u003ch3\>Dissecting X Inactivation\u003c/h3\>\n\n\u003cp\>\n\n\n\n\n\nOne of the two X chromosomes in mammalian females is randomly inactivated \n\nearly in development to match the single active X chromosome of males. \n\nThis process is regulated through the X-inactivation center (Xic). The two\n\nXics interact in \u003cem\>trans\u003c/em\> at the beginning of X-inactivation, \n\npresumably to allow reciprocal activation/inactivation. So far, single \n\ncopies of elements from the Xic have not been able to recapitulate X \n\ninactivation, suggesting additional elements must be required. \u003cb\>Augui \n\n\u003cem\>et al.\u003c/em\>\u003c/b\> (p. \u003ca href\u003d\"http://www.sciencemag.org/cgi/content/short/318/5856/1632\" target\u003d\"_blank\" onclick\u003d\"return top.js.OpenExtLink(window,event,this)\"\>1632\u003c/a\>)\n\nfind that a region ~200 kilobases upstream of the Xic--the \n\nX-pairing-region (\u003cem\>Xpr\u003c/em\>) --is sufficient in a single copy to allow \n\na transient interaction between the two Xics at a time before the \n\nbeginning of X inactivation. This pairing is cell cycle dependent, can \n\noccur from an ectopic location, and may activate the expression of \n\n",1]
);
//-->
Kang et al. (p. 1625; see the Perspective by Yeates and Clubb) describe the structure of the major pilin subunit from a Gram-positive human pathogen, Streptococcus pyogenes. In the crystal, the subunits associate in columns reminiscent of the likely arrangement in native pili. The structure also reveals intramolecular isopeptide bonds that may stabilize the structure and contribute to protease resistance. This could be a more general mechanism of protein stabilization in Gram-positive organisms, which lack the disulfide bond formation machinery of Gram-negative bacteria.
A recent survey of practicing physicians in the United States found that most physicians agreed with principles regarding fair distribution of resources, access to and quality of care, conflicts of interest, and self-regulation that were proposed by professional societies in 2002.
Although 96% of respondents agreed that physicians should report impaired or incompetent colleagues to relevant authorities, 45% of respondents who encountered such colleagues had not reported them.
Self-reported behaviors, however, showed that about one half did not follow self-regulation principles and that about one third would order unneeded magnetic resonance imaging for back pain in response to a patient's request.
Although 96% of respondents agreed that physicians should report impaired or incompetent colleagues to relevant authorities, 45% of respondents who encountered such colleagues had not reported them.
Self-reported behaviors, however, showed that about one half did not follow self-regulation principles and that about one third would order unneeded magnetic resonance imaging for back pain in response to a patient's request.
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