2nd Jul 2014, 12:35 PM #1231
Re: Health Bulletin
‘Smell’ of malaria attracts mosquitoes
Malaria may alter the way people smell to make them more alluring to mosquitoes, according to a new study that can help detect the deadly disease non-invasively through body odour.
An infection with malaria pathogens changes the scent of infected mice, making those infected more attractive to mosquitoes, experts have found. Malaria is transmitted to humans by the anopheles mosquito. The pathogen is a protozoan of the genus Plasmodium.
Researchers from ETH Zurich and Pennsylvania State University show that the plasmodium parasite appears to manipulate its host by changing the characteristics of the infected person's body odour, which makes the carrier more attractive to mosquitoes. Mosquitoes were most attracted to infected mice with a high concentration of gametocytes, the parasite's reproductive cells, in their blood. When the mosquito consumes these cells along with the blood, a new development cycle starts in the mosquito's gut.
However, the pathogens do not appear to trigger the expression of unique scent components. "There appears to be an overall elevation of several compounds that are attractive to mosquitoes," said Consuelo De Moraes, from ETH Zurich. The researchers believe it is logical that infected people smell more attractive but do not form highly specific body odours, especially given that the malaria pathogen can also have adverse effects on mosquitoes.
3rd Jul 2014, 12:53 AM #1232
Re: Health Bulletin
Less sleep may age your brain faster
Sleeping less? Your brain may age faster.
The less older adults sleep, the faster their brains age, a new study has warned.
The findings could have important implications for the rise of dementia among the elderly, researchers said.
Past research has examined the impact of sleep duration on cognitive functions in older adults.
Though faster brain ventricle enlargement is a marker for cognitive decline and the development of neurodegenerative diseases such as Alzheimer's, the effects of sleep on this marker have never been measured.
Researchers at Duke-NUS Graduate Medical School Singapore (Duke-NUS) examined the data of 66 older Chinese adults, from the Singapore-Longitudinal Ageing Brain Study.
The study started in 2005 and follows a cohort of healthy adults of Chinese ethnicity aged 55 years and above.
Participants underwent structural MRI brain scans measuring brain volume and neuropsychological assessments testing cognitive function every two years.
Additionally, their sleep duration was recorded through a questionnaire. Those who slept fewer hours showed evidence of faster ventricle enlargement and decline in cognitive performance.
"Our findings relate short sleep to a marker of brain ageing," said Dr June Lo, the lead author and a Duke-NUS Research Fellow.
"Work done elsewhere suggests that seven hours a day for adults seems to be the sweet spot for optimal performance on computer based cognitive tests. In coming years we hope to determine what's good for cardio-metabolic and long term brain health too," added Professor Michael Chee, senior author and Director of the Centre for Cognitive Neuroscience at Duke-NUS.
The research was published in the journal SLEEP.
3rd Jul 2014, 11:29 AM #1233
Re: Health Bulletin
Frozen testicle tissue test in mice raises fertility hope
For the first time, scientists have produced live offspring from deep frozen testicle tissue in mice, a breakthrough that could pave the way to preserve fertility of men left infertile by childhood cancer treatment.
Cryopreserved testicle tissue has been used to produce live mouse offspring for the first time. This indicates that the cryopreservation of testicle tissue may be a realistic measure for preserving fertility, researchers said.
"The cryopreservation of testis tissues followed by in vitro spermatogenesis, is promising to preserve the fertility of male paediatric cancer patients in the future," the team, led by Takehiko Ogawa of Japan's Yokohama City University Association of Medical Science, wrote in the journal Nature Communications.
Infertility is one of the adverse effects of certain cancer treatments. As cure rates for paediatric cancers increase, fertility has become an important concern for patients and their families.
Since semen cryopreservation is applicable only for postpubescent patients, alternative measures are necessary for younger patients, researchers said.
3rd Jul 2014, 11:30 AM #1234
Re: Health Bulletin
Muscle-driven 'bio bots' to walk as you wish
Imagine walking robots powered by muscle cells and controlled with electrical pulses that can give them an unprecedented command over their function.
Engineers at University of Illinois at Urbana-Champaign have demonstrated a class of "bio-bots" that are powered by a strip of skeletal muscle cells that can be triggered by an electric pulse.
"We are trying to integrate the principles of engineering with biology in a way that can be used to design and develop biological machines and systems for environmental and medical applications," explained Rashid Bashir, head of bioengineering at University of Illinois.
Skeletal muscles cells are very attractive because you can pace them using external signals, Bashir added.
The design is inspired by the muscle-tendon-bone complex found in nature.
There is a backbone of 3D printed hydrogel, strong enough to give the bio-bot structure but flexible enough to bend like a joint.
Two posts serve to anchor a strip of muscle to the backbone, like tendons attach muscle to bone, but the posts also act as feet for the bio-bot.
A bot's speed can be controlled by adjusting the frequency of the electric pulses.
A higher frequency causes the muscle to contract faster, thus speeding up the bio-bot's progress.
"The 'bio-bots' could eventually evolve into a generation of biological machines that could aid in drug delivery, surgical robotics, 'smart' implants, or mobile environmental analyzers, among countless other applications," said Caroline Cvetkovic, a graduate student and co-first author of the paper.
The group published its work in the online edition of Proceedings of the National Academy of Science.
4th Jul 2014, 12:16 AM #1235
Re: Health Bulletin
Teeth protein may help regenerate bone
Scientists have discovered that a teeth protein plays an important role in bone regeneration, a surprise finding that may benefit patients suffering from osteoporosis or bone fractures.
Normally found in the formation of enamel, which is an important component of teeth, a partial segment of the protein statherin can be used to signal bone growth, scientists at Queen Mary University of London found.
"What is surprising and encouraging about this research is that we can now use this particular molecule to signal cells and enhance bone growth within the body," said co-author Dr Alvaro Mata from QMUL's School of Engineering and Materials Science and the Institute of Bioengineering.
The team created bio-active membranes made from segments of different proteins to show which protein in particular played the crucial role.
They demonstrated the bone stimulating effect in a rat model, and used analytical techniques to visualize and measure the newly formed calcified tissue.
"The benefit of creating a membrane of proteins using these molecules means it can be both bio-active and easily handled to apply over injured areas in the bone," Co-author Dr Esther Tejeda-Montes also at QMUL's School of Engineering and Materials Science said.
"Our work enables the possibility to create robust synthetic bone grafts that can be tuned to stimulate the natural regenerative process, which is limited in most synthetic bone graft alternatives," Mata added.
The study was published in the journal Biomaterials.
4th Jul 2014, 12:19 AM #1236
Re: Health Bulletin
Dreaming is like being on 'mind-expanding' drugs, finds new study
Dreaming is like a drug trip - people experience enhanced associations, vivid imagination and an 'expanded consciousness'. Higher level thinking, including self-consciousness breaks down. These findings by a team of scientists from Germany and UK have for the first time shown the biological basis for 'mind expansion' produced by drugs like LSD and 'magic mushrooms'.
Scientists at the Imperial College, London collected brain imaging data from 15 volunteers who were given psilocybin, a chemical that causes psychedelic experiences, while they lay in a functional magnetic resonance imaging (fMRI) brain scanner. This data was analysed by experts from Goethe University, Germany. The findings are published in the journal Human Brain Mapping.
The study found that under psilocybin, activity in the more primitive brain network linked to emotional thinking became more pronounced, with several different areas in this network - such as the hippocampus and anterior cingulate cortex - active at the same time. This pattern of activity is similar to the pattern observed in people who are dreaming. Conversely, volunteers who had taken psilocybin had more disjointed and uncoordinated activity in the brain network that is linked to high-level thinking, including self-consciousness.
""What we have done in this research is begin to identify the biological basis of the reported mind expansion associated with psychedelic drugs,"" said Dr. Robin Carhart-Harris from Imperial College. ""I was fascinated to see similarities between the pattern of brain activity in a psychedelic state and the pattern of brain activity during dream sleep, especially as both involve the primitive areas of the brain linked to emotions and memory. People often describe taking psilocybin as producing a dreamlike state and our findings have, for the first time, provided a physical representation for the experience in the brain.""
Lead author Dr Enzo Tagliazucchi from Goethe University, Germany said: "A good way to understand how the brain works is to perturb the system in a marked and novel way. Psychedelic drugs do precisely this and so are powerful tools for exploring what happens in the brain when consciousness is profoundly altered. It is the first time we have used these methods to look at brain imaging data and it has given some fascinating insight into how psychedelic drugs expand the mind. It really provides a window through which to study the doors of perception."
Previous research has suggested that there may be an optimal number of dynamic networks active in the brain, neither too many nor too few. This may provide evolutionary advantages in terms of optimizing the balance between the stability and flexibility of consciousness. The mind works best at a critical point when there is a balance between order and disorder and the brain maintains this optimal number of networks. However, when the number goes above this point, the mind tips into a more chaotic regime where there are more networks available than normal. Collectively, the present results suggest that psilocybin can manipulate this critical operating point.
4th Jul 2014, 12:59 PM #1237
Re: Health Bulletin
Human mobility boosts spread of dengue: Study
Human mobility is more to blame for the spread of dengue than mosquitoes, says a study conducted by IITGandhinagar (IIT-Gn) on the incidence of the disease in the city. The study titled, 'Modelling spread of dengue epidemic in urban areas from a spatial interacting networks perspective', was carried out by Prof ShivakumarJolad and PhD student MuraliEnduri of IIT-Gn. The researchers also found that dengue was more common in densely inhabited urban areas than in regions with sparse population.
The research, conducted over a period of 7 years (from 2006 to 2012), studied the incidence of the disease at the ward level in Ahmedabad city. Prof Jolad analyzed the data received from Ahmedabad Municipal Corporation's entomologist Dr VK Kohli to examine the spatial spread of dengue in different wards. "We found that, on an average, there is a delay of about two months from the onset of monsoon to the peak in detected dengue cases. This is primarily due to multiple stages of the dengue virus's lifecycle in the mosquito," Jolad said.
The dengue lifecycle includes stages in human beings as well as the Aedes Aegepti mosquito. The monsoon provides ample stagnant water for the dengue mosquito to start breeding. When this mosquito bites an already infected person it also becomes infected and becomes a host to the virus. When the infected mosquito bites another human being, it passes on the infection to him. There is an incubation period between being bitten by a dengue mosquito and showing symptoms of the disease. "This explains the two-month delay, between the onset of monsoon and the incidence of the disease reaching a peak," said Jolad, who is an assistant professor in physics at IIT-Gn.
The study also says that dengue, as a disease, is spread more by humans than by mosquitoes. A mosquito can fly distances up to 25 to 30 metres in a day but infected human beings can travel much longer distances. "This allows the virus to travel to newer places where the cycle of infection is repeated," said Jolad. The study, which has been presented at various conferences, suggests that an effective plan for preventing dengue outbreak would require devising of vector control strategies and minimizing of vector-to-human transmission of the virus.
Densely populated areas at greater risk
Highlighting the greater prevalence of the disease in urbanized areas, the study says that population density and stagnant water which provides the dengue mosquito an opportunity to breed are the main reasons of the higher incidence of the disease in these areas.
In Ahmedabad, dengue cases were initially found mainly in the south-east of the city such as Gomtipur, Dani Limbda, Vatva and Odhav. Gomtipur used to have the highest number of confirmed cases but this came down over the years. By 2012, however, the disease had spread across the entire city. For instance, Giridhar Nagar used to have very few cases but, by 2012, it had the maximum number of dengue cases in Ahmedabad (37 confirmed). Dengue cases in Dani Limbda have been consistently high with an average of 14 cases confirmed by the AMC every year, per 1,00,000 people. On the western side of river Sabaramati, Vejalpur has recorded the highest average of 14 cases per year.
Dengue preventive measures should focus mainly on densely populated regions, slums and areas with stagnant water bodies, says the study.
5th Jul 2014, 04:59 PM #1238
Re: Health Bulletin
Scientists find new formation of coronary vascular population
A new formation of distinct coronary vascular population in the neonatal heart has been discovered by Chinese scientists that they say may provide new strategies for the treatment of myocardial infarction.
The breakthrough published on the Science magazine website on Friday, points out that a substantial portion of postnatal coronary vessels form in the neonatal mouse heart instead of expanding from pre-existing embryonic vasculature, state-run Xinhua news agency reported.
According to professor Zhou Bin with the Chinese Academy of Sciences, lineage conversion of neonatal endocardial cells during trabecular compaction generates a distinct compartment of the coronary circulation located within the inner half of the ventricular wall.
This lineage conversion provides an efficient means of rapidly augmenting the coronary vasculature, Bin said.
The finding is expected to provide clues for understanding and stimulating cardiovascular regeneration following injury and disease, he said.
Myocardial infarction caused by coronary artery disease is a major cause of deaths.
5th Jul 2014, 05:00 PM #1239
Re: Health Bulletin
Doctors cut out 'largest' salivary gland tumour
Doctors at a city hospital have created a record of sorts by removing what they say is the largest salivary grand tumour. A 28-year-old man, who could not eat any solid food for 3-4 months due to the tumour, was operated on by ENT surgeons at Lok Nayak Hospital.
Doctors said the patient was referred to them from Ambedkar Hospital in Rohini last month. "The tumours of the salivary gland are usually small in size and easily operable. This was large?extending from the middle of the neck to the skull base. The patient could not eat anything and even breathing was becoming difficult. Had we not operated on time, he would have died within days," Dr Vikas Malhotra, associate professor, ENT and head and neck surgery at Maulana Azad Medical College and associated hospitals (Lok Nayak), said.
The patient first underwent tracheostomy?a surgical procedure to create an opening through the neck into the trachea or windpipe?to ease food intake and the breathing mechanism. "Five days after that, on June 10, his condition stabilized and we decided to operate on him for resection of the tumour," Dr Malhotra said.
The weight of the tumour, resected successfully in a three-hour long surgery, was 420g. The largest tumour reported so far in medical literature weighed only 87.3 grams, said the doctor.
"The tumour we removed is seven times bigger in cuboid volume compared to any previous reports," Dr Malhotra said. He said the patient is experiencing normal breathing and normal oral intake. "We discharged him a few days ago. We intend to publish this case in leading surgical journals and present it to record books," said a doctor.
Tumours of the salivary gland, say medical experts, are rare and cause difficulties in surgical management. There are nonspecific symptoms that are hard to diagnose, allowing the tumour to grow very large.
6th Jul 2014, 10:58 AM #1240
Re: Health Bulletin
Gene tests to detect cancer get thumbs down from doctors
Senior doctors have raised the red flag against targeting consumers directly for gene-based blood tests to detect the presence of cancer and its various stages.
Dr B Krishna, a senior nuclear medicine specialist, said patients had started demanding that their doctors use genetic tests as they are non-invasive and painless to detect cancer. "Patients don't seem to realize that these blood tests are still in an investigational stage. The established tests, on the other hand, are 100% right ," he said.
Medical oncologist Dr Sandeep Goyle concurred, saying these gene-based tests for cancer are new and still not widely used across the world.
The one that has, in particular, riled specialists is the circulatory tumour cell test that, as the name suggests, gives a result based on the volume of circulating cancer cells found in a blood sample. "Circulating cell evaluation for cancer, the so-called liquid biopsy, will eventually become more widespread," said radiologist Dr Bhavin Jhankaria, adding, "but currently there aren't enough studies that help us understand their utility."
Gene tests are widely viewed as an evolution of diagnostic methods in every medical specialty. In 2004, the US FDA approved blood-based gene testing for colon, breast and prostate cancers.
The entire genome testing made its debut in India two years ago, with specific tests offering a total lifetime risk analysis of various diseases such as diabetes, cancer, hypertension and so on becoming available. Now, gene testing companies have begun offering CTC testing as well, forcing associations such as the Society of Nuclear Medicine India to react.
"In 2007, the American Society of Clinical Oncology advised against CTC testing for the diagnosis of advanced breast cancer," said a letter by the Society of Nuclear Medicine India. The association's letter signed by Dr Anshu R Sharma and Dr Basant Malpani pointed out that, in 2010, the American Joint Committee on Cancer did not include CTC tests in its cancer staging system.
"Direct-to-customer circulating cell advertisements mislead patients into believing that there is now some new magic method of evaluating cancer, as compared to the traditional, well-established methods of tissue biopsies, histopathology and radiologic investigations, including PET/CT," said Dr Jhankaria. He said such marketing methods could jeopardize the future use of these technologies and, more importantly, prevent patients from taking correct decisions.
Dr Krishna said some patients had already voiced their concern about undergoing PET scans that uses a nuclear isotope to detect cancer when gene-based blood tests were available. "Benefits from PET-CT studies far outweigh radiation risks. Radiation exposure from medical imaging is a very small fraction of the total radiation received in an individual's lifetime," he said.
However, gene testing companies insist it's not an "either or" question. Gene testing is complementary to present testing systems. "Over the past decade, advances in genetic technologies have allowed researchers to characterize the genetic mutations in a wide range of cancers, providing researchers and clinicians with a comprehensive view of cancer development and offered unique pharmacogenetic opportunities to target specific genetic mutations that are key drivers of the disease process," Sumit Jamuar of the Global Gene Corporation said.
Identification of genetic mutations in a patient allows testing to be offered to other family members to determine if they too are at an increased risk for cancer.