5th Apr 2016, 01:50 PM #2381
Re: Health Bulletin
3D ‘mini-retinas’ grown from human stem cells
Scientists have developed an efficient way to make 3D "mini retinas", which mimic the organ's tissue organisation, from mouse or human stem cells.
The research offers new perspectives on the growth, injury and repair of retina — the part of the eye that is sensitive to light.
"The goal isn't just to make the closest thing next to a real retina, but also to possibly harness the flexibility of the system to create more diverse ways of studying retina tissue," said Mike Karl of the German Centre for Neurodegenerative Diseases (DZNE).
Stem cell technologies have the potential to develop therapies for the treatment of diseases such as age-related blindness.
Stem cell biologists have been working to understand the regeneration of neurons from lower vertebrates to humans, which can aid regenerative medicine in more indirect ways.
For example, the 3D retinal organoids developed in Karl's lab efficiently replicate the formation of the retina.
This specifically includes the light-detecting cone cells, which now can be produced in high quantities in their mini-retinas.
Cone photoreceptors, which are responsible for high acuity and colour vision, are the most precious retinal cell type with regard to potential future cell replacement therapies in patients affected by retinal degeneration.
Researchers' comparative studies on pluripotent stem cell-derived human and mouse retina organoids and mouse retina in vivo support the power of the new organoid protocol.
"Tissue heterogeneity is a major challenge in organoid systems, and here our work provides new insight, which will help to develop specific organoid-based models, specifically to reliably study retinal disease mechanism," said Karl.
The Karl Lab's change to the mini-retina protocol involves cutting a retina organoid grown from stem cells into three pieces at an early stage of eye development.
Each of these pieces, which look like little half moons, eventually grows into the full suite of cells found in the retina, thereby increasing the yield of retinal organoids up to 4-fold compared to previous protocols.
A trisection also spurs the surviving organoids to grow to reach sizes similar to uncut organoids.
These mini-retinas swim around in the dish and because they are not attached to a surface, better reflect the structure of retinal tissue during development.
The study was published in the journal Stem Cell Reports.
6th Apr 2016, 12:59 PM #2382
Re: Health Bulletin
Climate change threatens hearts, lungs and also brains- US study
Climate change can be expected to boost the number of annual premature US deaths from heat waves in coming decades and to increase mental health problems from extreme weather like hurricanes and floods, a US study said on Monday.
"I don't know that we've seen something like this before, where we have a force that has such a multitude of effects," Surgeon General Vivek Murthy told reporters at the White House about the study. "There's not one single source that we can target with climate change, there are multiple paths that we have to address."
Heat waves were estimated to cause 670 to 1,300 US deaths annually in recent years. Premature US deaths from heat waves can be expected to rise more than 27,000 per year by 2100, from a 1990 baseline, one scenario in the study said. The rise outpaced projected decreases in deaths from extreme cold.
Extreme heat can cause more forest fires and increase pollen counts and the resulting poor air quality threatens people with asthma and other lung conditions. The report said poor air quality will likely lead to hundreds of thousands of premature deaths, hospital visits, and acute respiratory illness each year by 2030.
Climate change also threatens mental health, the study found. Post traumatic stress disorder, depression, and general anxiety can all result in places that suffer extreme weather linked to climate change, such as hurricanes and floods. More study needs to be done on assessing the risks to mental health, it said.
Cases of mosquito and tick-borne diseases can also be expected to increase, though the study, completed over three years, did not look at whether locally-transmitted Zika virus cases would be more likely to hit the United States.
President Barack Obama's administration has taken steps to cut carbon emissions by speeding a switch from coal and oil to cleaner energy sources. In February, the Supreme Court dealt a blow to the White House's climate ambitions by putting a hold Obama's plan to cut emissions from power plants. Administration officials say the plan is on safe legal footing.
John Holdren, Obama's senior science adviser, said steps the world agreed to in Paris last year to curb emissions through 2030 can help fight the risks to health.
"We will need a big encore after 2030 ... in order to avoid the bulk of the worst impacts described in this report," he said.
7th Apr 2016, 11:20 AM #2383
Re: Health Bulletin
Pig hearts may save human lives: Researchers
One day, cardiac patients may enjoy a new lease on life with pig hearts beating in their chests, said researchers reporting a major advance Tuesday in cross-species organ transplantation.
Given the dire shortage of organ donors, the use of animal hearts, lungs or livers to save human lives has long been a holy grail of medical science. But organ rejection has stood stubbornly in the way.
On Tuesday, scientists from the United States and Germany said they had succeeded in keeping transplanted pig hearts alive in baboons, primate cousins of humans, for a record 2.5 years.
Their method uses a combination of gene modification and targeted immune-suppressing drugs.
"It is very significant because it brings us one step closer to using these organs in humans," said study co-author Muhammad Mohiuddin of the National Heart, Lung and Blood Institute in Maryland.
"Xenotransplants- organ transplants between different species- could potentially save thousands of lives each year that are lost due to a shortage of human organs for transplantation," he told AFP by email.
In experiments with five baboons, the hearts survived for up to 945 days, breaking previous records held by the same group of researchers.
The hearts did not replace those of the monkeys, but were connected to the circulatory system via two large blood vessels in the baboon abdomen. The transplanted heart beat like a normal heart, but the baboon's own heart continued the function of pumping blood- a known method in studying organ rejection.
Donor organs are often rejected by a recipient's immune system, which can recognise it as foreign, and thus a threat.
In this trial, the donor organs came from pigs which had been genetically modified to have high tolerance to immune response, basically making them invisible to the recipient's natural defence system. The scientists also added a human genetic signature to the pigs that help prevent blood clotting.
The recipient baboons were given a drug that suppresses immune response. Scientists have been experiment with the transplantation of primate kidneys, hearts and livers into humans since the 1960s. None survived beyond a few months.
Given their genetic proximity to humans, primates were initially thought to be the best donor candidates. But there is no large source of captive-bred apes -- which take long to grow and mature, and some like chimpanzees are endangered.
Their genetic closeness also poses a higher danger of inter-species disease transmission, as well as ethical questions.
Pigs have since emerged as better donors. Their hearts are anatomically similar to ours, they pose less of a disease transmission risk, they grow up fast and are already widely farmed.
In these xenotransplant trials, baboons serve as human models.
The next big test will be full pig-to-baboon heart transplants, said Mohiuddin, adding that porcine hearts could make their way into human chests "in the foreseeable future".
"In our opinion, this regimen appears potentially safe for human application for patients suffering from end-stage organ failure who might be candidates for initial trials of xenotransplantation," wrote the study authors.
The work was published in the journal Nature Communications.
7th Apr 2016, 11:20 AM #2384
Re: Health Bulletin
Impulsive people 'prone' to substance abuse: Study
People who are prone to seeking excitement and acting impulsively may have differences in the structure of their brains, which may also predispose them to substance abuse, a new study has found.
Scientists found that increased impulsivity and sensation-seeking in healthy young adults was linked to distinct differences in their brain structures - the areas involved in decision-making and self-control had a thinner cortex, the brain's wrinkled outer layer or gray matter.
Researchers from Yale University, Harvard University and Massachusetts General Hospital examined the variability in brain structure among 1,234 males and females aged 18 to 35 with no history of psychiatric disorders or substance dependence.
Using magnetic resonance imaging (MRI), they measured the size of particular regions of the brain for each participant.
The participants also completed questionnaires assessing traits associated with sensation-seeking and impulsivity such as their need for novel and intense experiences, willingness to take risks, and a tendency to make rapid decisions.
They also reported alcohol, tobacco and caffeine usage.
Researchers found that people who reported seeking high levels of stimulation or excitement had reduced cortical thickness, or gray matter, in brain regions associated with decision making and self-control.
The strongest links occurred in brain areas related to the ability to regulate emotions and behaviour, the anterior cingulate and middle frontal gyrus.
Changes in those brain structures also correlated with participants' self-reported tendency to act on impulse and with heightened use of alcohol, tobacco, or caffeine.
"The findings allow us to have a better understanding of how normal variation in brain anatomy in the general population might bias both temperamental characteristics and health behaviours, including substance abuse," said Avram Holmes from Yale University.
The findings were published in The Journal of Neuroscience.
7th Apr 2016, 11:22 AM #2385
Re: Health Bulletin
World is facing 'unrelenting march' of diabetes: WHO
The number of adults living with diabetes has nearly quadrupled to 422 million over 35 years, the WHO warned on Wednesday, adding the world is facing an "unrelenting march" of the disease which now affects nearly one in 11 people.
A major new report by the World Health Organisation (WHO) has warned that the diabetes cases have risen to 422 million in 2014 from 108 million in 1980, 314 million more.
High blood sugar levels are a major killer - linked to 3.7 million deaths around the world each year, the report said.
The numbers would continue to increase unless "drastic action" was taken, officials said.
Published in The Lancet journal ahead of the United Nations World Health Day on April 7, the study used data from 4.4 million adults in different world regions to estimate age-adjusted diabetes prevalence for 200 countries.
It found that between 1980 and 2014, diabetes has become more common among men than women, and rates of diabetes rose significantly in many low and middle income countries, including China, India, Indonesia, Pakistan, Egypt and Mexico.
The report clubs both type 1 and type 2 diabetes together, but the surge in cases is predominantly down to type 2 - the form closely linked to poor lifestyle.
There is no known way to prevent type one, which occurs when the pancreas does not produce enough insulin, the hormone that regulates blood sugar levels.
Most people living with diabetes have type 2, which is associated with obesity and other lifestyle factors and emerges in adults and increasingly among children.
To curb the intensifying burden of the disease, huge efforts are needed to change "eating and physical activity habits," especially early in life, when key behavioural patterns are formed, WHO said.
"There is a critical window for intervention to mitigate the risk of obesity and type 2 diabetes later in life," the report said.
It noted that rising consumption of sugary drinks and other fattening foods was a key factor, but drew particular attention to high rates of physical inactivity.
According to worldwide 2010 figures, nearly a quarter of people over 18 did not do the minimum recommended amount of physical activity per week, with women recorded as less active than men.
The WHO recommends that adults between 18 to 65 get at least 150 minutes of moderate physical activity — including things like walking, jogging and gardening — per week.
"Physical inactivity is alarmingly common among adolescents," the report added, noting that the excessively sedentary lifestyles were more acute in high-income countries than low-income countries.
In 2014, one in four adults were overweight, while one in 10 were defined as obese, according to WHO figures.
The WHO estimated that the annual global cost of diabetes, including health care needs, exceeds $827 billion (728 billion euros).
Citing a separate study, the agency said the global GDP losses linked to diabetes could reach $1.7 trillion by 2030, with the damage split roughly evenly between developed and developing nations.
Noting both the health and macroeconomic damage caused by the growing diabetes epidemic, WHO chief Margaret Chan called for a coordinated, holistic response.
This should include greater efforts to curb smoking, a push to entrench physical activity in education systems and working with food companies to promote availability of healthier products, the organisation said.
As with obesity, WHO has stressed that putting excessive blame on individuals for eating too much or not exercising enough ignores several key factors, including the obstacles to eating healthily in some societies.
Complicating the response in lower-income countries is the limited availability and high cost of insulin in many areas, WHO said.
"Effectively addressing diabetes does not just happen: it is the result of collective consensus and public investment in interventions that are affordable, cost-effective and based on the best available science," Chan said in a statement.
7th Apr 2016, 01:51 PM #2386
Re: Health Bulletin
முன்னோரின் ஆவி, வஞ்சிக்கப்பட்டவர் பேயாக வருவது. வேற்று கிரகமனிதர்கள் உடலை ஆக்கிரமிப்பது. இப்படி தூக்கத்தில் மனம் விழித்து, உடலை அசைக்க முடியாமல் போகும் நிலையை விளக்க பேச்சுவழக்கில் பலகதைகள் சொல்லப்படுவதுண்டு. அவையெல்லாம் கட்டுக்கதைகளே.
'ஸ்லீப் பாராலிசிஸ்' எனப்படும் உறக்க வாதத்தை தூக்கவியல் வல்லுனர்கள் விரிவாக ஆராய்ந்திருக்கின்றனர். அவர்களது தீர்ப்பு: இது சில விநாடிகள் முதல் சில நிமிடங்கள் வரை நீடிக்க லாம்; இது எந்த வயதினருக்கும் வரலாம் என்றாலும் பதின் வயதினர், இருபதுகளில் இருப்பவர்களுக்கு வரவாய்ப்புக்கள்அதிகம்.
நமக்கு ஆழ்ந்த தூக்கம் படிப்படியாக ஏற்படு கிறது. உடலின் இயக்க நரம்புகளும், தசைகளும் ஒய்வெடுக்க முதலில் ஆரம்பித்து, பிறகு மூளையின் சிலவிழிப்புணர்வுப் பகுதிகள் கதவை சாத்த ஆரம்பிக்கின்றன.
அதேபோல விழித்தெழுவதும் படிப்படியாக நடக்கிறது. இந்தபடி நிலைகளில் சிறிய இடறல் நேரும்போது, சிந்திக்கக்கூடிய, சுற்றிலும் நடப்பதை உணரக் கூடிய நிலையில் இருந்தாலும், உடலை எவ்வளவு முயற்சி செய்தும் அசைக்க முடியாத நிலை ஏற்படலாம். சில மருந்துகள் உண்பதால் பக்கவிளைவாகவோ, பல நாட்கள் தூக்கம் கெடுவதாலோ, போதைப் பழக்கம் இருப்பதாலோ உறக்க வாதம் வரக்கூடும். அதேபோல, தூக்கம் தொடர்பான நோய்கள் உள்ளவர்களுக்கு இந்தநிலை அடிக்கடி வரக்கூடும்
10th Apr 2016, 12:13 PM #2387
Re: Health Bulletin
மனிதர்கள் 10 ஆண்டுகள் கூடுதலாக வாழ மாத்திரை விஞ்ஞானிகள் தயாரிப்பு
வழக்கத்தை விட மனிதர்கள் நீண்ட காலம் உயிர் வாழ புதிய ஆய்வுகள் நடத்தப்பட்டு வருகின்றன. அந்த வகையில் தற்போது ஐரோப்பியா நாடுகளை சேர்ந்த 2 நிறுவனங்களை சேர்ந்த விஞ்ஞானிகள் ஆராய்ச்சி நடத்தினார்கள்.
பொதுவாக உடலில் உள்ள ஜி.எஸ்.கே. - 3 என்ற புரோட்டீன் மூலக்கூறுகள் மனிதர்களின் வாழ்நாளை குறைக்கின்றன. அவற்றை கட்டுப்படுத்தி ஆயுளை நீட்டுவது குறித்து ஆய்வு மேற்கொள்ளப்பட்டது.
அதற்கு பழ வண்டுகள் பயன் படுத்தப்பட்டன. அவற்றின் உடலில் குறைந்த அளவில் லித்தியம் என்ற ரசாயன பொருட்களை செலுத்தினர். இதன் மூலம் அவை வழக்கத்தை விட 16 சதவீத அளவு கூடுதலாக உயிர் வாழ்ந்தன.
அதே முறையில் புதிய மாத்திரை தயாரித்து மனிதர்கள் வழக்கத்தை விட கூடுதலாக 10 ஆண்டுகள் வாழ வழிவகை செய்ய முடியும் என விஞ்ஞானிகள் கருதுகின்றனர்.
11th Apr 2016, 11:50 PM #2388
Re: Health Bulletin
Smokers have harder time getting work: study
People who smoke may find it harder to get work, and make less money than non-smokers, according to a US study out Monday.
The findings in the Journal of the American Medical Association (JAMA) Internal Medicine were based on more than 250 unemployed job-seekers in the San Francisco area.
About half smoked cigarettes -- on average 13 per day -- and the other half did not smoke.
Researchers checked in with them six and 12 months after they enrolled in the study to see how their job hunts were going.
"We found that smokers had a much harder time finding work than nonsmokers," said lead author Judith Prochaska associate professor of medicine at Stanford University.
After one year, 56 percent of non-smokers had found work, compared to only 27 percent of smokers.
Among those who had jobs, smokers earned an average of $5 per hour less than nonsmokers.
Smokers who managed to get work earned an average of $15.10 per hour, compared to $20.27 per hour for nonsmokers.
Nearly two-thirds of those in the study were men. Participants' average was 48.
Whites made up 38.2 percent of the study, African-Americans were 35.9 percent, and the remaining subjects were Hispanic, Asian or "other" race.
One third of those studied had a college degree.
The study had some limits, including its small size and its geographic location in health-conscious northern California, where smoking can carry a significant stigma.
There were also some key differences between the groups in their analysis: smokers tended to be younger, less-educated and in poorer health than nonsmokers.
"We designed this study's analyses so that the smokers and nonsmokers were as similar as possible in terms of the information we had on their employment records and prospects for employment at baseline," said co-author Michael Baiocchi, an assistant professor of medicine at Stanford.
The study urged employment service agencies to use the findings to "raise awareness of tobacco-related costs, wage losses, health harms and associations with lower reemployment success," and to connect job-seekers to resources that could help them quit smoking.
14th Apr 2016, 04:08 PM #2389
Re: Health Bulletin
Zika causes severe birth defects, confirms US
US health officials have concluded that infection with the Zika virus in pregnant women is a cause of the birth defect microcephaly and other severe brain abnormalities in babies.
"It is now clear, the CDC has concluded, that Zika virus does cause microcephaly," Tom Frieden, director of the US Centers for Disease Control and Prevention, said in a conference call with reporters on Wednesday. "There isn't any doubt that Zika causes microcephaly."
US and world health officials have been saying for some time that mounting scientific evidence points to the mosquito-borne virus as the likely cause of the alarming rise in microcephaly in Zika-hit areas of Brazil. It had not been declared as the definitive cause until now.
Never before in history has a bite from a mosquito been seen as the cause of birth defects, Frieden said.
CDC officials said their advice to pregnant women won't change. Pregnant women should avoid traveling to places where the Zika virus is spreading, mostly in Latin America and the Caribbean.
16th Apr 2016, 03:35 AM #2390
Re: Health Bulletin
Scientists control heart cells with laser
In a first, scientists have found a way to control the behaviour of heart muscle cells using laser radiation - paving the way to develop better understanding of the heart's mechanisms to treat conditions like acute arrhythmia which is responsible for causing one in eight deaths globally.
"Right now, this result may be very useful for clinical studies of the mechanisms of the heart and in the future, we could potentially stop attacks of arrhythmia in patients at the touch of a button," said study co-author Konstantin Agladze from the Moscow Institute of Physics and Technology.
In order to study the heart disorder, Agladze's team created "arrhythmia in vitro", using azoTAB (azobenzene trimethylammonium bromide) whose molecule consists of two benzene rings connected by a bridge of two nitrogen atoms.
If the molecule is irradiated with UV light, the benzene rings change position relative to one another, they "fold" and under the influence of visible light, the rings return to their original configuration.
An azoTAB molecule can, therefore, exist in two states -- switching between them under the influence of radiation.
The team "taught" the azoTAB molecules to control cardiomyocytes so that one configuration did not prevent voluntary contractions (passive), and the other (active) "deactivated" contractions.
Using a device similar to a projector, but with a laser instead of a lamp, the scientists created at each point the required concentration of the active form of azoTAB.
This enabled them to control the cardiomyocytes in each specific point of the heart.
The experiment, detailed in the journal PLOS ONE, showed that the effect of azoTAB on a cell is reversible.
This means that the results of the experiments can be used in research and clinical practice, which could potentially lead to an effective treatment for arrhythmias.