11th Apr 2014, 03:10 AM #981
Re: Health Bulletin
Sneeze produces gas cloud
Researchers have found that a human sneeze produces a gas cloud that keeps potentially infectious droplets aloft over much greater distances than previously realized.
The smaller droplets that emerge in a cough or sneeze may travel five to 200 times further than they would if those droplets simply moved as groups of unconnected particles as previous estimates had assumed.
The tendency of these droplets to stay airborne re-suspended by gas clouds means that ventilation systems may be more prone to transmitting potentially infectious particles than had been suspected.
Researchers used high-speed imaging of coughs and sneezes as well as laboratory simulations with mathematical modelling to produce a new analysis of coughs and sneezes from a fluid-mechanics perspective.
"When you cough or sneeze, you see the droplets or feel them if someone sneezes on you," says John Bush, a professor of applied mathematics at MIT. "But you don't see the cloud, the invisible gas phase. The influence of this gas cloud is to extend the range of the individual droplets particularly the small ones."
The study found that droplets 100 micrometres or millionths of a meter in diameter travel five times farther than previously estimated while droplets 10 micrometres in diameter travel 200 times farther.
Droplets less than 50 micrometres in size can frequently remain airborne long enough to reach ceiling ventilation units.
A cough or sneeze is a "multiphase turbulent buoyant cloud," as the researchers term it in the paper because the cloud mixes with surrounding air before its payload of liquid droplets falls out, evaporates into solid residues or both.
"The cloud entrains ambient air into it and continues to grow and mix. But as the cloud grows it slows down and so is less able to suspend the droplets within it. You thus cannot model this as isolated droplets moving ballistically," the scientists added.
11th Apr 2014, 12:55 PM #982
Re: Health Bulletin
Scientists create world's first vagina in lab using patients' tissues
In a path-breaking procedure, scientists have carried out successful vaginal implant in four women using engineered tissues.
A team of scientists in the US and Mexico, led by Professor Anthony Atala from Wake Forest School of Medicine, implanted tissue-engineered vaginal organs in four women, aged 13-18 years. The women suffered from a condition known as Mayer-Rokitansky-Kuster-Hauser syndrome that causes the vagina to be underdeveloped or absent.
After transplantation, the organs continue to function as if they were native tissues and all recipients are sexually active, report no pain and remain satisfied with their desire/arousal, lubrication and orgasm, according to British medical journal 'The Lancet'.
The team obtained a vulvar tissue from each patient from which they grew smooth muscle cells and vaginal epithelial cells in the lab. The cells were then placed onto specially designed vagina-shaped biodegradable scaffolds and left to grow for seven days. The researchers then surgically implanted the engineered vaginas which remain structurally and functionally normal.
Prof Atala said, "Tissue biopsy samples show that the reconstructed tissue is histologically and functionally similar to normal vaginal tissue. This technique is a viable option for vaginal reconstruction and has several advantages over current reconstructive methods because only a small biopsy of tissue is required, and using vaginal cells may reduce complications that arise from using non-vaginal tissues (segments of large intestine or skin) such as infection and graft shrinkage."
According to professor Martin Birchall of UCL London, "They have not only successfully treated several patients with a difficult clinical problem, but addressed some of the most important questions facing translation of tissue-engineering technologies." "The steps between first-in-human experiences such as those reported here and their use in routine clinical care remain many, including larger trials with long-term follow-up, the development of clinical grade processing, scale-out and commercialisation. However, these hurdles are common to all potentially disruptive technologies and many countries now have large translational income streams, engaged biotech companies and streamlined regulatory processes that may reduce the time to routine use significantly."
11th Apr 2014, 12:58 PM #983
Re: Health Bulletin
Your childhood memories go further back than you think, new study says
It is generally believed by psychologists that the earliest memories of any person go back to about 3.5 years of age. Now, a new study led by a Cornell University scientist indicates that people may be able to remember even earlier events, but they mistakenly shift the time to later. This shifting starts in childhood and even adults make similar mistakes.
The study also found that girls had better memories and could go back further in time than boys, on an average.
The researchers asked a group of kids aged 4-13 years to remember the earliest event in their lives and also their age at the time. Then returned a year or two later to ask again about earliest memories - and at what age the children were when the events occurred.
But the children who originally answered, for example, "I think I was 3 years old when my dog fell through the ice," postdated that same earliest memory by as much as nine months when asked - in follow-up interviews a year or two years later - to recall again. In other words, as time went by, children thought the same memory event occurred at an older age than they had thought previously.
"The age estimates of earliest childhood memories are not as accurate as what has been generally assumed," report Qi Wang of Cornell University and Carole Peterson of Memorial University of Newfoundland in the March 2014 online issue of Developmental Psychology. "Using children's own age estimates as the reference, we found that memory dating shifted to later ages as time elapsed."
Childhood amnesia refers to our inability to remember events from our first years of life. Until now, cognitive psychologists estimated the so-called childhood amnesia cutoff at 3.5 years - the average age of our very earliest memory, the authors noted in their report. But the research on kids has prompted Wang and Peterson to question the 3.5-year cutoff for childhood amnesia.
"This can happen to adults' earliest childhood memories, too," says Wang, professor of human development and director of the Social Cognition Development Laboratory in Cornell's College of Human Ecology. "We all remember some events from our childhood. When we try to reconstruct the time of these events, we may postdate them to be more recent than they actually were, as if we are looking at the events through a telescope. Although none of us can recall events on the day of our birth - childhood amnesia may end somewhat earlier than the generally accepted 3.5 years."
Parents might help because they have more clues (e.g., where they lived, what their children looked like at the time of events) to put their children's experiences along a timeline. When asked, for example, "How old was Evan when Poochie fell through the ice?" they erred less than Evan had. Still, they are not free from errors in their time estimates.
The only way to settle that, Wang and Peterson mused, would be to look for documented evidence - a parent's diary, for instance, or a newspaper account of Poochie's memorable rescue.
The study confirmed a finding made by Wang in 2013 that a gender-related difference existed as far as extent of memories goes.
"Females generally, although not always, exhibit superior retention of episodic memories than males," Wang and Peterson wrote in the 2014 report. The gender differences, according to the researchers, may reflect the development of life narratives in late childhood and early adolescence, where girls often tell lengthier and more coherent life stories than boys.
"The narrative organization of life events," they speculated, "may allow girls to better remember the events over time, compared with boys."
12th Apr 2014, 11:33 AM #984
Re: Health Bulletin
10 lakh Indians diagnosed with cancer every year, study finds
Every year, 10 lakh Indians are diagnosed with cancer and another six to seven lakh die of it. And it's feared that, by 2035, these numbers may almost double to 17 lakh new patients and 12 lakh deaths per year.
These projections are part of a special research paper on Indian cancer published in Lancet Oncology journal. Stating that cancer has "devastating economic and human costs" in India, over 40 experts from across the globe have asked Indian politicians, who are busy with electioneering at the moment, to concentrate on public health programmes for cancer.
More cancer specialists, more hospitals and more money for research for India-specific affordable treatment are needed to change the cancer graph of India, said the paper, written mainly by researchers at King's College in London and Tata Memorial Hospital in Parel, Mumbai.
One of the authors, Dr C S Pramesh from Tata Memorial Hospital, said the worst aspect of India's cancer picture is poor life expectancy. Over 60% of cancer patients in the US enjoy an over five-year survival rate, but the corresponding figure for India is 30%. "It's worrying that between 60% and 70% of our patients die earlier mainly because they seek treatment only after their disease has reached an advanced stage,'' said Dr Pramesh. Incidentally, India has a relatively lower incidence of cancer—around a quarter of that in the US or Western Europe. But the rate of deaths is similar to that seen in high-income countries.
The study's lead author, Dr Richard from King's College, told TOI, "India is a demographically young country. Even though rates of cancer are lower than in high-income countries, the absolute numbers still make this a massive public health burden, and in the next 20 to 30 years India will rapidly 'age' and catch up with the rates in other countries."
The latest Lancet Oncology issue, in fact, focuses on India, China and Russia, as they account for 46% of all new cancer cases worldwide and 52% of all cancer deaths globally. It found that over two-thirds (71%) of cancer deaths in India occur in patients aged 30 to 69, with a significant number of premature deaths of people in the prime of their lives.
12th Apr 2014, 11:40 AM #985
Re: Health Bulletin
Doctors engineer human cartilage graft from nasal septum cartilage cells
In a major boost for lab made organs, doctors have engineered a human cartilage graft from patients' own nasal septum cartilage cells to successfully rebuild the nostrils (alar lobule) of five individuals whose noses were damaged by skin cancer.
Doctors from the University of Basel in Switzerland have published the results of the transplant one year later on Friday in the British medical journal, The Lancet.
They said that one year after reconstruction all five recipients were satisfied with their ability to breathe, as well as the cosmetic appearance of their nose and did not report any local or systemic adverse events.
The nose is the most common site of non-melanoma skin cancer, because of its cumulative exposure to sunlight, with the highest frequency of cancer occurring on the alar lobule. Currently, when removing skin cancers, surgeons often have to cut away parts of cartilage, (for instance from the nasal septum, ear, or rib) as grafts to functionally reconstruct the tumour excision site.
However, this painful and invasive procedure involves major additional surgery, and has been associated with complications at the site from which cartilage has been removed.
A team from the University investigated an alternative approach using engineered cartilage tissue grown from patients' own cells.
They extracted the cartilage cells (chondrocytes) from the nasal septum of each patient, and multiplied the cells by exposing them to growth factors for two weeks.
The expanded cells were seeded onto collagen membranes and cultured for two additional weeks, generating cartilage 40 times larger than the original biopsy. When the engineered grafts were ready they were shaped according to the defect and implanted.
This new technique was applied on five patients, aged 76 to 88 years, with severe defects on their nose after skin cancer surgery.
12th Apr 2014, 11:41 AM #986
Re: Health Bulletin
Study shows men, women in more satisfying relationships have lower testosterone
Many people assume that the more testosterone, the better, but a new University of Michigan study finds that might not always be the case in romantic relationships.
Low testosterone levels may be a good thing for both men and women, who reported more satisfaction and commitment to their relationships when they had lower levels.
Higher testosterone is generally thought to be associated with attracting sexual partners, but might not be compatible with some kinds of long-term relationships, said Robin Edelstein, U-M associate professor of psychology and the study's lead author.
"The assumption is generally that high testosterone is good for sexual relationships," she said. "These findings suggest that once people are in a relationship, lower levels of testosterone may be beneficial—or may reflect better ongoing relationship dynamics."
Previous studies have examined how testosterone levels are associated with the quality of men's relationships, but the U-M research is among the first to demonstrate the association among women.
The study used data from 39 heterosexual couples whose ages ranged from 18 to 31 and were in relationships from two months to seven years. They answered questions about their satisfaction ("My relationship is close to ideal"), commitment ("I want our relationship to last forever") and investment ("I have invested a great deal into our relationship that I would lose if the relationship were to end"). Participants also provided their saliva for analysis.
Researchers concluded that the quality of a person's relationship was associated with his/her own and his/her partner's testosterone levels. Both men's and women's testosterone was negatively correlated with their own and their partner's satisfaction and commitment. The couples were more satisfied and committed when they or their partner had low testosterone levels, the research indicated.
12th Apr 2014, 02:54 PM #987
Re: Health Bulletin
Youngsters too at risk of Parkinson's disease: Doctors
Karthik*, 24, could sense gradual changes in his behaviour. He suddenly became tired for a few hours in a day, was distracted easily and there were frequent mood swings. Since these were tell-tale signs of depression, doctors prescribed a number of anti-psychotic drugs. But the situation got worse. Finally, a visit to a neurologist revealed he had Parkinson's. The disease thought to affect the elderly, is affecting youngsters too.
Dr Sathish Kumar, neurologist and stroke specialist at Fortis Malar, said Parkinson's was a progressive movement disorder that affected nerve cells responsible for the body's motor functions. "In Karthik's case, no one would have considered Parkinson's an issue given his age. But we are seeing many youngsters, some even below 30 years, with Young Onset Parkinson's Disease (YOPD). The symptoms are different from the disease that affects old people," he said. While patients show signs of tremors and lack of control over their body movements, people with YOPD display behavioural changes and experience stiffness of muscles that make their actions sluggish.
Trauma and head injuries are also a reason for youngsters developing Parkinson's, said Dr K Sridhar, neurologist at Global Health City. "In Parkinson's disease, the nerves function abnormally due to lack of a brain chemical called dopamine. Sometimes when a person sustains a head injury, part of the brain that produces the chemical might get damaged leading to the onset of the disease," he said. Lifestyle changes and stress can trigger small vessel diseases in the brain, he said.
Dr Sathish warned that there are chances of YOPD being mistaken as a psychological disorder as symptoms are similar. "
Early recognition is the keyas medicines will help in getting them back on track," he said.
12th Apr 2014, 07:56 PM #988
Re: Health Bulletin
3D printed cancer cells to mimic tumors
Researchers have successfully created a 3D model of a cancerous tumour using a 3D printer, an advance that can be used to test the efficacy and safety of new cancer drugs and therapies.
The model, which consists of a scaffold of fibrous proteins coated in cervical cancer cells, has provided a realistic 3D representation of a tumour's environment and could help in the discovery of new drugs and cast new light on how tumours develop, grow and spread throughout the body.
The model consists of a grid structure, 10 mm in width and length, made from gelatin, alginate and fibrin, which recreates the fibrous proteins that make up the extracellular matrix of a tumour.
The grid structure is coated in Hela cells - a unique, 'immortal' cell line that was originally derived from a cervical cancer patient in 1951.
Although the most effective way of studying tumours is to do so in a clinical trial, ethical and safety limitations make it difficult for these types of studies to be carried out on a wide scale.
With the advent of 3D printing, it is now possible to provide a more realistic representation of the environment surrounding a tumour, which the researchers have demonstrated in this study by comparing results from their 3D model with results from a 2D model.
In addition to testing if the cells remained viable, or alive, after printing, the researchers also examined how the cells proliferated, how they expressed a specific set of proteins, and how resistant they were to anti-cancer drugs.
The proteins studied were part of the MMP protein family. These proteins are used by cancer cells to break through their surrounding matrix and help tumours to spread.
Resistance to anti-cancer drugs, which was also studied, is a good indicator of tumour malignancy.
The results revealed that 90 per cent of the cancer cells remained viable after the printing process.
"We have provided a scalable and versatile 3D cancer model that shows a greater resemblance to natural cancer than 2D cultured cancer cells," said Professor Wei Sun, from Tsinghua University, China, and Drexel University, US.
The study was published the journal Biofabrication.
13th Apr 2014, 11:23 AM #989
Re: Health Bulletin
Smoking ruins your taste buds
There is another reason why you should not smoke, especially if you are fond of coffee and tasty food, as smoking harms taste buds, research has confirmed.
Smokers do not enjoy their coffee despite the strong, bitter taste of caffeine being easily detected. It seems their ability to taste is impaired by toxic chemicals found in tobacco, even after they have quit smoking.
As part of the study, scientists tested how well 451 volunteers could recognise the four basic flavours of sweet, sour, bitter and salty, as well as the intensity of each taste.
Researchers found that whether the volunteers smoked or not did not affect whether they could recognise salty, sweet or sour tastes, but it did have an effect where the bitter taste of caffeine was concerned.
One in five smokers and one in four ex-smokers could not correctly recognise the taste.
However, 13 percent of non-smokers also failed the taste test.
Researchers believe the build-up of tobacco in the body could stop taste buds renewing themselves and so harm a person's ability to recognise certain tastes, even after they have stopped smoking.
The findings of the study have been published in the latest edition of the journal 'Chemosensory Perception'.
13th Apr 2014, 11:29 AM #990
Re: Health Bulletin
Mental well-being: A gateway to happiness
A middle-aged man walked into my clinic in his designer outfit. "I have everything doctor. God has given me a wonderful, loving family, great friends and a flourishing business. But I am not happy," he said.
Happiness: a subjective state of contentment and well-being; an aspiration of every The United Nation's World Happiness Report (2013) found the world's happiest countries to be Denmark, Norway, Switzerland, Netherlands and Sweden. India unfortunately ranked at 111th, behind most of its neighbouring countries. The study also found mental health to be the single most important determinant of individual happiness globally. It emphasized that depressive and anxiety disorders are the single biggest cause of disability, absenteeism, misery and economic waste worldwide (United Nations, 2013).
So what factors determine happiness? Studies suggest that over 33% is accounted for by genetics (De Neve et al., 2013). Brain circuits such as the nucleus accumbens (the brain's pleasure centre) are involved, which when stimulated, make people smile, laugh, feel pleasure and happiness. Several neurochemicals play a role. For instance, dopamine, associated with positive emotion, activates the reward system. Serotonin helps maintain a positive mood. Endorphins lower pain perception and increase a sense of calm and well-being. Happy people enjoy greater immunity, better health, better relationships and increased longevity. The reverse is true for unhappy people. Reason enough to make pursuing Of course, everyone is unhappy from time to time; this is normal. Unhappiness becomes a problem when it persists, turning into recurrent depressed moods, with symptoms such as sleep and appetite disturbances, low self-esteem, decreased interest and energy, diminished concentration, etc.
After a detailed assessment, it emerged that our patient (reporting persistent unhappiness) in fact had recurrent clinical major depression. After a detailed discussion, treatment was initiated with a combination of medication, counseling, and later, with rTMS (Repetitive Transcranial Magnetic Stimulation); he responded well to How can one enhance one's Happiness Quotient (HQ)? People are good at synthesizing happiness, says Daniel Gilbert, a Harvard Psychology professor. Psychologist Ed Diener found the frequency of positive experiences is a much better predictor of happiness than the intensity of positive experiences. The UN study for instance, found people in happy nations (Denmark and Netherlands) ride bicycles by choice. What an eco-friendly, and fun way to enhance happiness.
Do figure out your personal happiness mantra. As for me, I am getting myself a bicycle (and a helmet!). Hopefully, the bicycling will stimulate my nucleus accumbens and happy neurochemicals, steering me along the road to happiness. What about you?