Category: Health

{As little as 10 minutes a day of high-intensity physical activity could help some children reduce their risk of developing heart problems and metabolic diseases such as diabetes, according to an international study led by a researcher at Wake Forest Baptist Medical Center.}

The investigators found that replacing light-intensity physical activity with brief periods of vigorous exercise may provide significant cardiometabolic benefits in young people with relatively large waist measurements and elevated levels of insulin in their blood.

The study, published in the current issue of the journal Medicine & Science in Sports & Exercise, analyzed data from 11,588 young people ages 4 to 18 who were included in 11 International Children’s Accelerometry Database studies in the United States, Brazil and European countries. The researchers focused on those records that included the child’s age, gender, level of physical activity and at least one biomarker — a measurable indicator of a medical state or condition — of a cardiometabolic risk. These included weight circumference, systolic and diastolic blood pressure and bloodstream levels of HDL (“good”) cholesterol, LDL (“bad”) cholesterol, triglycerides, glucose and insulin.

In evaluating the relationships between the biomarkers and vigorous physical activity while controlling for various factors (including age, gender, duration and level of exercise and sedentary time) the researchers found only 32 significant associations out of a possible 360. All 32 were related to reduced waist circumference and insulin levels. The relationships between high-intensity exercise and the other biomarkers were inconsistent.

“The results suggest that substituting modest amounts of vigorous physical activity for longer-duration light exercise may have cardiometabolic benefits above and beyond those conveyed by moderate activity and the avoidance of sedentary behavior,” said the study’s lead author, Justin B. Moore, Ph.D., associate professor of family and community medicine at Wake Forest School of Medicine, part of Wake Forest Baptist. “But as vigorous activity was independently associated with only two of the markers examined, it may be that its truly meaningful benefits may be limited, relative to less-intense exercise.”

Moore suggests that further studies incorporating additional variables — such as dietary and genetic data — are needed to better establish the relationships between various levels of exercise and cardiometabolic biomarkers in young people. “If such studies provide robust results,” he said, “a relatively brief but intense dose of physical activity — perhaps as little as 10 minutes day, which is certainly feasible for most youth — could turn out to be part of a ‘prescription’ for children to achieve or maintain cardiac and metabolic health.”

Source:Science Daily

{How a disease outbreak affects a group of animals depends on the breakdown of ages in the population, research has shown.}

The findings could help scientists better understand how events such as disease outbreaks may affect certain groups in a population.

Scientists sought to examine how a spread of ages can influence a population’s health, by simulating an outbreak of disease in small marine animals.

With lab experiments and computer modelling, they found that disease spread can vary depending on the age at which individuals are exposed to infection, and the age at which females in the group become mothers.

Experiments in the latest study found that offspring of younger mothers were more at risk from infection. The finding builds upon previous knowledge that younger individuals are more at risk.

Taking these factors into account, computer models showed that when death rates are high, disease can spread faster — even as populations fall. This contradicts the expectation that disease should spread most easily in dense populations, in which individuals interact more.

Researchers from the University of Edinburgh carried out lab experiments with water fleas, examining how four generations of the small crustaceans responded to a common bacterial infection. Their results were used to build a mathematical model of how the organisms might respond in the long term to threats such as incidence of disease.

Their study, published in Ecology Letters, was funded by the Natural Environment Research Council and the Wellcome Trust.

Jess Clark, of the University of Edinburgh’s School of Biological Sciences, who led the study, said: “Many societies around the world are experiencing aging populations, and investigating the impact of this might lend valuable insight into how such populations might respond to an outbreak of disease.”

Source:Science Daily

{A more nuanced approach to role of alcohol in heart health is needed, researchers say}

Moderate drinking is associated with a lower risk of several, but not all, cardiovascular diseases, finds a large study of UK adults published by The BMJ (March 22).

The finding that moderate drinking is not universally associated with a lower risk of all cardiovascular conditions suggests a more nuanced approach to the role of alcohol in prevention of cardiovascular disease is necessary, say the researchers.

Moderate drinking is thought to be associated with a lower risk of developing cardiovascular disease compared with abstinence or heavy drinking.

In the UK, moderate drinking is defined as no more than 14 units (112 grams) of alcohol a week.

To put this into context, one unit of alcohol is about equal to half a pint of ordinary strength beer, lager or cider (3.6% alcohol by volume) or a small pub measure (25 ml) of spirits. There are one and a half units of alcohol in small glass (125 ml) of ordinary strength wine (12% alcohol by volume). [Source: NHS Choices]

There is, however, a growing scepticism around this observation, with some experts pointing out several shortcomings in the evidence. For example, grouping non-drinkers with former drinkers, who may have stopped drinking due to poor health.

So researchers at the University of Cambridge and University College London set out to investigate the association between alcohol consumption and 12 cardiovascular diseases by analysing electronic health records for 1.93 million healthy UK adults as part of the CALIBER (ClinicAl research using LInked Bespoke studies and Electronic health Records) data resource.

All participants were free from cardiovascular disease at the start of the study, and non-drinkers were separated from former and occasional drinkers to provide additional clarity in this debate.

After several influential factors were accounted for, moderate drinking was associated with a lower risk of first presenting to a doctor with several, but not all, cardiovascular conditions, including angina, heart failure and ischaemic stroke, compared with abstaining from alcohol.

However, the authors argue that it would be unwise to encourage individuals to take up drinking as a means of lowering their cardiovascular risk over safer and more effective ways, such as increasing physical activity and stopping smoking.

Heavy drinking (exceeding recommended limits) conferred an increased risk of first presenting with a range of such diseases, including heart failure, cardiac arrest and ischaemic stroke compared with moderate drinking, but carried a lower risk of heart attack and angina.

Again, the authors explain that this does not mean that heavy drinkers will not go on to experience a heart attack in the future, just that they were less likely to present with this as their first diagnosis compared with moderate drinkers.

This is an observational study, so no firm conclusions can be drawn about cause and effect. Added to which, the authors point to some study limitations that could have introduced bias.

Nevertheless, they say it is the first time this association has been investigated on such a large scale and their findings have implications for patient counselling, public health communication, and disease prediction tools.

In a linked editorial, researchers at Harvard Medical School and Johns Hopkins School of Public Health in the US say this study “does not offer a materially new view of the associations between alcohol consumed within recommended limits and risk of cardiovascular disease.

“This work, however, sets the stage for ever larger and more sophisticated studies that will attempt to harness the flood of big data into a stream of useful, reliable, and unbiased findings that can inform public health, clinical care, and the direction of future research,” they conclude.

Source:Science Daily

{Researchers in the United States have developed a computer program that can simultaneously detect cancer and identify where in the body the cancer is located, from a patient’s blood sample. The program is described in research published this week in the open access journal Genome Biology.}

Professor Jasmine Zhou, co-lead author from the University of California at Los Angeles, said: “Non-invasive diagnosis of cancer is important, as it allows the early diagnosis of cancer, and the earlier the cancer is caught, the higher chance a patient has of beating the disease. We have developed a computer-driven test that can detect cancer, and also identify the type of cancer, from a single blood sample. The technology is in its infancy and requires further validation, but the potential benefits to patients are huge.”

The program works by looking for specific molecular patterns in cancer DNA that is free flowing in the patients’ blood and comparing the patterns against a database of tumour epigenetics, from different cancer types, collated by the authors. DNA from tumour cells is known to end up in the bloodstream in the earliest stages of cancer so offers a unique target for early detection of the disease.

Professor Zhou explained: “We built a database of epigenetic markers, specifically methylation patterns, which are common across many types of cancer and also specific to cancers originating from specific tissue, such as the lung or liver. We also compiled the same ‘molecular footprint’ for non-cancerous samples so we had a baseline footprint to compare the cancer samples against. These markers can be used to deconvolute the DNA found freely in the blood into tumor DNA and non-tumor DNA.”

In this study, the new computer program and two other methods (called Random Forest and Support Vector Machine) were tested with blood samples from 29 liver cancer patients, 12 lung cancer patients and 5 breast cancer patients. Tests were run 10 times on each sample to validate the results. The Random Forest and Support Vector Machine methods had an overall error rate (the chance that the test produces a false positive) of 0.646 and 0.604 respectively, while the new program obtained a lower error rate of 0.265.

Twenty-five out of the 29 liver cancer patients and 5 out of 12 lung cancer patients tested in this study had early stage cancers, which the program was able to detect in 80% of cases. Although the level of tumour DNA present in the blood is much lower during the early stages of these cancers, the program was still able to make a diagnosis demonstrating the potential of this method for the early detection of cancer, according to the researchers.

Professor Zhou added: “Owing to the limited number of blood samples, the results of this study are evaluated only on three cancer types (breast, liver and lung). In general, the higher the fraction of tumor DNAs in blood, the more accurate the program was at producing a diagnostic result. Therefore, tumors in well-circulated organs, such as the liver or lungs are easier to diagnose early using this approach, than in less-circulated organs such as the breast.”

Source:Science Daily

{More Americans than ever are turning to spiritual, meditative and religious retreats as a way to reset their daily life and enhance wellbeing. Now, researchers at The Marcus Institute of Integrative Health at Thomas Jefferson University show there are changes in the dopamine and serotonin systems in the brains of retreat participants. The team published their results in Religion, Brain & Behavior.}

“Since serotonin and dopamine are part of the reward and emotional systems of the brain, it helps us understand why these practices result in powerful, positive emotional experiences,” said Andrew Newberg, M.D., Director of Research in the Marcus Institute of Integrative Health. “Our study showed significant changes in dopamine and serotonin transporters after the seven-day retreat, which could help prime participants for the spiritual experiences that they reported.”

The post-retreat scans revealed decreases in dopamine transporter (5-8 percent) and serotonin transporter (6.5 percent) binding, which could make more of the neurotransmitters available to the brain. This is associated with positive emotions and spiritual feelings. In particular, dopamine is responsible for mediating cognition, emotion and movement, while serotonin is involved in emotional regulation and mood.

The study, funded by the Fetzer Institute, included 14 Christian participants ranging in age from 24 to 76. They attended an Ignatian retreat based on the spiritual exercises developed by St. Ignatius Loyola who founded the Jesuits. Following a morning mass, participants spent most of the day in silent contemplation, prayer and reflection and attended a daily meeting with a spiritual director for guidance and insights. After returning, study subjects also completed a number of surveys which showed marked improvements in their perceived physical health, tension and fatigue. They also reported increased feelings of self-transcendence which correlated to the change in dopamine binding.

“In some ways, our study raises more questions than it answers,” said Dr. Newberg. “Our team is curious about which aspects of the retreat caused the changes in the neurotransmitter systems and if different retreats would produce different results. Hopefully, future studies can answer these questions.”

Source:Science Daily

{Johns Hopkins Kimmel Cancer Center scientists report data from a new study providing evidence that random, unpredictable DNA copying “mistakes” account for nearly two-thirds of the mutations that cause cancer. Their research is grounded on a novel mathematical model based on DNA sequencing and epidemiologic data from around the world.}

“It is well-known that we must avoid environmental factors such as smoking to decrease our risk of getting cancer. But it is not as well-known that each time a normal cell divides and copies its DNA to produce two new cells, it makes multiple mistakes,” says Cristian Tomasetti, Ph.D., assistant professor of biostatistics at the Johns Hopkins Kimmel Cancer Center and the Johns Hopkins Bloomberg School of Public Health. “These copying mistakes are a potent source of cancer mutations that historically have been scientifically undervalued, and this new work provides the first estimate of the fraction of mutations caused by these mistakes.”

“We need to continue to encourage people to avoid environmental agents and lifestyles that increase their risk of developing cancer mutations. However, many people will still develop cancers due to these random DNA copying errors, and better methods to detect all cancers earlier, while they are still curable, are urgently needed,” says Bert Vogelstein, M.D., co-director of the Ludwig Center at the Johns Hopkins Kimmel Cancer Center.

Tomasetti and Vogelstein conducted the new study described in a report published March 24 in the journal Science.

The researchers say their conclusions are in accord with epidemiologic studies showing that approximately 40 percent of cancers can be prevented by avoiding unhealthy environments and lifestyles. But among the factors driving the new study, say the researchers, is that cancer often strikes people who follow all the rules of healthy living — nonsmoker, healthy diet, healthy weight, little or no exposure to known carcinogens — and have no family history of the disease, prompting the pained question “Why me?”

Tomasetti and Vogelstein believe the answer to this question rests in random DNA copying errors. Current and future efforts to reduce known environmental risk factors, they say, will have major impacts on cancer incidence in the U.S. and abroad. But they say the new study confirms that too little scientific attention is given to early detection strategies that would address the large number of cancers caused by random DNA copying errors.

“These cancers will occur no matter how perfect the environment,” says Vogelstein.

In a previous study authored by Tomasetti and Vogelstein in the Jan. 2, 2015, issue of Science, the pair reported that DNA copying errors could explain why certain cancers in the U.S., such as those of the colon, occur more commonly than other cancers, such as brain cancer.

In the new study, the researchers addressed a different question: What fraction of mutations in cancer are due to these DNA copying errors?

To answer this question, the scientists took a close look at the mutations that drive abnormal cell growth among 32 cancer types (Supplemental Materials, Table S6). They developed a new mathematical model using DNA sequencing data from The Cancer Genome Atlas and epidemiologic data from the Cancer Research UK database.

According to the researchers, it generally takes two or more critical gene mutations for cancer to occur. In a person, these mutations can be due to random DNA copying errors, the environment or inherited genes. Knowing this, Tomasetti and Vogelstein used their mathematical model to show, for example, that when critical mutations in pancreatic cancers are added together, 77 percent of them are due to random DNA copying errors, 18 percent to environmental factors, such as smoking, and the remaining 5 percent to heredity.

In other cancer types, such as those of the prostate, brain or bone, more than 95 percent of the mutations are due to random copying errors.

Lung cancer, they note, presents a different picture: 65 percent of all the mutations are due to environmental factors, mostly smoking, and 35 percent are due to DNA copying errors. Inherited factors are not known to play a role in lung cancers.

Looking across all 32 cancer types studied, the researchers estimate that 66 percent of cancer mutations result from copying errors, 29 percent can be attributed to lifestyle or environmental factors, and the remaining 5 percent are inherited.

The scientists say their approach is akin to attempts to sort out why “typos” occur when typing a 20-volume book: being tired while typing, which represents environmental exposures; a stuck or missing key in the keyboard, which represent inherited factors; and other typographical errors that randomly occur, which represent DNA copying errors. “You can reduce your chance of typographical errors by making sure you’re not drowsy while typing and that your keyboard isn’t missing some keys,” says Vogelstein. “But typos will still occur because no one can type perfectly. Similarly, mutations will occur, no matter what your environment is, but you can take steps to minimize those mutations by limiting your exposure to hazardous substances and unhealthy lifestyles.”

Tomasetti and Vogelstein’s 2015 study created vigorous debate from scientists who argued that their previously published analysis did not include breast or prostate cancers, and it reflected only cancer incidence in the United States.

However, Tomasetti and Vogelstein now report a similar pattern worldwide, supporting their conclusions. They reasoned that the more cells divide, the higher the potential for so-called copying mistakes in the DNA of cells in an organ. They compared total numbers of stem cell divisions with cancer incidence data collected by the International Agency for Research on Cancer on 423 registries of cancer patients from 68 countries other than the U.S., representing 4.8 billion people, or more than half of the world’s population. This time, the researchers were also able to include data from breast and prostate cancers. They found a strong correlation between cancer incidence and normal cell divisions among 17 cancer types, regardless of the countries’ environment or stage of economic development.

Tomasetti says these random DNA copying errors will only get more important as societies face aging populations, prolonging the opportunity for our cells to make more and more DNA copying errors. And because these errors contribute to a large fraction of cancer, Vogelstein says that people with cancer who have avoided known risk factors should be comforted by their findings. “It’s not your fault,” says Vogelstein. “Nothing you did or didn’t do was responsible for your illness.”

In addition to Tomasetti and Vogelstein, Lu Li, a doctoral student in Tomasetti’s laboratory in the Department of Biostatistics at the Johns Hopkins Bloomberg School of Public Health, also contributed to the research. Funding for the research was provided by the John Templeton Foundation, the Lustgarten Foundation for Pancreatic Cancer Research, the Virginia and D.K. Ludwig Fund for Cancer Research, the Sol Goldman Center for Pancreatic Cancer Research, and the National Institutes of Health’s National Cancer Institute (CA006973, CA43460, and CA62924).

Vogelstein is a member of the scientific advisory boards of Morphotek, Exelixis GP, and Syxmex Inostics, and is a founder of PapGene and Personal Genome Diagnostics. Morphotek, Syxmex Inostics, PapGene, and Personal Genome Diagnostics, as well as other companies, have licensed technologies from The Johns Hopkins University on which Vogelstein is an inventor. These licenses and relationships are associated with equity or royalty payments to Vogelstein. The terms of these arrangements are being managed by The Johns Hopkins University in accordance with its conflict of interest policies.

Source:Science Daily

{Human hormone, protein linked to bone mass are impacted by 12 months of targeted exercise}

Osteoporosis affects more than 200 million people worldwide and is a serious public health concern, according to the National Osteoporosis Foundation. Now, Pamela Hinton, associate professor in the Department of Nutrition and Exercise Physiology, has published the first study in men to show that long-term, weight-bearing exercises decrease sclerostin, a protein made in the bone, and increase IGF-1, a hormone associated with bone growth. These changes promote bone formation, increasing bone density.

“People may be physically active, and many times people know they need to exercise to prevent obesity, heart disease or diabetes,” Hinton said. “However, you also really need to do specific exercises to protect your bone health.”

In the study, men 25- to 60-years-old who had low-bone mass were split into two groups. One group performed resistance training exercises such as lunges and squats using free weights. The other group performed various types of jumps, such as single-leg and double-leg jumps. After 12 months of performing the exercises, Hinton then compared the levels of bone proteins and hormones in the blood.

“We saw a decrease in the level of sclerostin in both of these exercise interventions in men,” Hinton said. “When sclerostin is expressed at high levels, it has a negative impact on bone formation. In both resistance and jump training, the level of sclerostin in the bone goes down, which triggers bone formation.”

The other significant change Hinton observed was an increase in the hormone IGF-1. Unlike sclerostin, IGF-1 triggers bone growth. The decrease of harmful sclerostin levels and the increase in beneficial IGF-1 levels confirmed Hinton’s prior research that found both resistance training and jump training have beneficial effects on bone growth.

To increase bone mass and prevent osteoporosis, Hinton recommends exercising specifically to target bone health. While exercises such as swimming and cycling are beneficial to overall health, these activities do not strengthen the skeleton. Hinton suggests also doing exercise targeted for bone health, such as resistance training and jump training.

The study, “Serum sclerostin decreases following 12 months of resistance- or jump-training in men with low bone mass,” was published in Bone.

Source:Science Daily

{Surprisingly, the neurons are located in a brain region thought to be linked with fear}

Scientists have long believed that the central amygdala, a structure located deep within the brain, is linked with fear and responses to unpleasant events.

However, a team of MIT neuroscientists has now discovered a circuit in this structure that responds to rewarding events. In a study of mice, activating this circuit with certain stimuli made the animals seek those stimuli further. The researchers also found a circuit that controls responses to fearful events, but most of the neurons in the central amygdala are involved in the reward circuit, they report.

“It’s surprising that positive-behavior-promoting subsets are so abundant, which is contrary to what many people in the field have been thinking,” says Susumu Tonegawa, the Picower Professor of Biology and Neuroscience and director of the RIKEN-MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory.

Tonegawa is the senior author of the study, which appears in the March 22 issue of the journal Neuron. The paper’s lead authors are graduate students Joshua Kim and Xiangyu Zhang.

{{Driving behavior}}

The paper builds on a study published last year in which Tonegawa’s lab identified two distinct populations of neurons in a different part of the amygdala, known as the basolateral amygdala (BLA). These two populations are genetically programmed to encode either fearful or happy memories.

In that study, the researchers found that the neurons encoding positive and negative memories relay information to different parts of the central amygdala. In their new work, they set out to further clarify the connections from the two BLA populations to the central amygdala, and to determine the functions of the central amygdala cells that receive information from the BLA.

First, the researchers analyzed the genetic profiles of the central amygdala neurons and divided them into seven groups based on the genetic markers they express and their anatomical location. They then used optogenetics, a technique that allowed them to control neuron activity with light, to investigate the functions of each population.

The researchers found that five of these populations stimulate reward-related behavior: When the mice were exposed to light, the mice repeatedly sought more light exposure because these neurons were driving a reward circuit. These same populations all receive input from the positive emotion cells in the BLA.

Another population of neurons underlies fear-related innate and memory behaviors, and the last population was not required for either fear- or reward-related behavior.

This finding contradicts the consensus that the central amygdala is involved primarily in fear-related behavior, the researchers say.

“Classically people have generalized the central amygdala as a fear-related structure. They think it’s involved in anxiety and fear-related responses,” Kim says. “However, it looks like the structure as a whole mainly seems to participate in appetitive behaviors.”

The researchers cannot rule out the possibility that some yet-to-be-discovered cells in the central amygdala control negative behavior, they say. “However, the cells that we have identified so far represent more than 90 percent of the central amygdala,” Tonegawa says. “If there are some other cells for negative behavior, it’s a small fraction.”

{{Surprising circuits}}

In another surprising finding, the researchers discovered that the fear-linked neurons they identified in the central amygdala do not send messages directly to the part of the brain that is believed to receive fear-related input from the central amygdala. This part of the brain, the periaqueductal gray (PAG), is located in the brainstem and plays a role in responding to pain, stress, and external threats.

Still unknown is where those central amygdala cells send their output, and whether it eventually gets to the PAG after stopping somewhere else. Tonegawa’s lab is now trying to trace these circuits further to find out where they go.

The researchers are also studying the role of BLA neurons in fear extinction, which is the process of rewriting fearful memories so that they are associated with more positive feelings. This approach is often used to treat disorders such as depression and posttraumatic stress disorder.

Source:Science Daily

{The amount of time spent watching TV daily can have a negative impact on a man’s fertility according to researchers at Copenhagen University.}

The study which was published in the American Journal of Epidemiology found that watching more than five hours of TV a day can slash a man’s sperm count by a third.

The researchers made this conclusion after studying 1,200 healthy young men to see if a couch potato lifestyle can affect a man’s fertility.

The researchers found that binge-watchers had average sperm counts of 37 million per millilitre of fluid compared to 52 million per millilitre among men who hardly watch TV.

Surprisingly, the researchers found that spending time sitting at a computer didn’t affect a man’s fertility like watching TV did. The researchers suggested this could be because men who watch too much TV are less likely to be doing much exercise or eating healthily, which are crucial habits for maintaining fertility.

Source:Elcrema