New York / Heidelberg, 1 July 2011
Evolution of sport performances follows a physiological law
Study suggests performance peaks from 20 to 30 years of age, then declines irreversibly
Geoffroy Berthelot and Stephane Len, both researchers at the IRMES (Institut de Recherche bioMédicale et d'Epidemiologie du Sport at INSEP, Paris, France), have published their findings in AGE, the official journal of the American Aging Association, describing the evolution of performances in elite athletes and chess grandmasters. This article is congruous with the epidemiological approaches developed by the laboratory, and suggests that changes in individual performance are linked to physiological laws structuring the living world.Physiological parameters that characterize human capabilities (mobility, reproduction or the capacity to perform tasks) evolve throughout the life cycle. The physical and intellectual abilities follow the same pattern, starting at the moment of conception: The performance of each individual is limited at birth, then increases to a peak before declining until death. With these findings, Geoffroy Berthelot and Stephane Len modeled the careers of more than 2,000 athletes (from a panel of 25 Olympic disciplines) and grandmasters of chess. They demonstrate a simple relation between changes in performance and the age of individuals.The results of this study validate a model previously published by Moore: The evolution of the performances of an individual throughout his life follows an exponential growth curve to a peak before declining irreversibly, following another negative exponential curve. This peak is reached at the age of 26.1 years for the disciplines studied: athletics (26.0 years), swimming (21.0 years) and chess (31.4 years). For each data set, the evolution curve is representative of a range of 91.7% of the variance at the individual level and 98.5% of the variance in terms of sport events. Moreover, these cycles are observable in other physiological parameters such as the development of lung function or cognitive skills, but also at the level of cells, organisms and populations, reflecting the fractal properties of such a law.This study suggests that technical change, energy consumption and development strongly influenced the performance of individuals. These have increased significantly over the last century compared to today's values. Ultimately, the modeling of changes in performance with age can be extended to all individuals and lead to an estimate of life expectancy.Further research will refine these descriptive models and apply them to other areas of human activity (scientific, economic, ecological ...), and test their viability, which may help to assess the relationships of man to his environment.ReferenceBerthelot G and Len S et al (2011). Exponential growth combined with exponential decline explains lifetime performance evolution in individual and human species. AGE; DOI 10.1007/s11357-011-9274-9
Public release date: 19-Jun-2011
Contact: Dr. Hilary Glover
Proteins used to map the aging process
Loss of muscle mass is not only associated with disease, such as HIV and cancer, but also with the normal aging process. Anabolic steroids are sometimes used to reverse loss of lean muscle tissue but they can have unwanted side effects. New research, published in BioMed Central's open access journal Immunity and Aging, shows that nine proteins, isolated from blood, alter with age and that the profile of some of these proteins can be reversed by testosterone treatment.
In a combined study, researchers from Boston University School of Medicine and University of Texas Medical Branch compared protein levels in serum samples from two groups of healthy men - young men aged 18-35 and older men aged 60-75. Seven proteins, which were either growth factors (IGF-1, IL-7, IL-12p40, PDGFβ), or were involved in immune response (ENA78, MIP-1β, IP-10), and pro-collagen (PIIINP) were all reduced in older men. In contrast the monokine MIG, also involved in immune activity, was elevated.
Testosterone treatment increased lean muscle mass, and levels of the appetite suppressing hormone leptin, for both groups of men. Testosterone also increased levels of PIIINP and IGF-1 in young men and the researchers saw a similar increase in a small group of older men.
Dr Monty Montano said, "The blood proteins we found that altered with healthy aging also have links to maintenance of muscle, such as IGF-1 and pro-collagen, or are involved in regulation of the immune system, possibly reducing T-cell and neutrophil responses with age. Additionally all of the proteins we found are involved with the signaling pathways controlled by AKT, NFκβ and TGFβ which are known to be associated with aging."
Dr Montano continued, "It is no simple matter to find a one size fits all test for aging – our results suggest that there is a difference in response to anabolic steroids between young and older men, despite both groups increasing in muscle mass. It seems that testosterone replacement does not necessarily mean a restoration of full testosterone functionality for the older man."
Notes to Editors
1. Identification of serum biomarkers for aging and anabolic response
Please name the journal in any story you write. If you are writing for the web, please link to the article. All articles are available free of charge, according to BioMed Central's open access policy.
2. Immunity & Ageing is an Open Access, peer-reviewed, online journal that considers manuscripts on all aspects of ageing examined from an immunological point of view.
3. BioMed Central (http://www.biomedcentral.com/) is an STM (Science, Technology and Medicine) publisher which has pioneered the open access publishing model. All peer-reviewed research articles published by BioMed Central are made immediately and freely accessible online, and are licensed to allow redistribution and reuse. BioMed Central is part of Springer Science+Business Media, a leading global publisher in the STM sector.
Public release date: 4-Jun-2011
Indiana U. study points to health disparities in physical fitness
An Indiana University study examining disparities in physical fitness levels between older adults who are patients of safety net community health centers (CHC) and those who are members of a medically affiliated fitness center is producing stunning results.
NiCole Keith, associate professor in the Department of Physical Education at Indiana University-Purdue University Indianapolis, said she expected the study to show similar physical fitness levels between the two groups. The findings, however, show that the fitness center participants performed significantly better on each of the measures when compared to the CHC particpants.
The community health centers serve vulnerable populations, including those without health insurance; the medically affiliated fitness centers serve a more affluent population. Otherwise, the age and health literacy of study participants in both groups were the same.
Further, the members of the medically affiliated fitness center were not exercising at the facility every week, much less every day. Generally, these fitness center members had sedentary jobs. Patients at the CHC who were employed spent a lot of time on their feet and moving about.
"I expected their physical fitness levels wouldn't be different, but they are so different that it is startling," Keith said. "Seven indicators of physical fitness were tested, and members of the medically affiliated fitness center scored higher than the CHC patients in every category."
Keith discussed "Disparities in Physical Fitness Between Fitness Center and Safety Net Community Health Center Members" on Saturday, June 4, at the American College of Sports Medicine meeting in Denver. Her poster session was from 9:30-11 a.m. MDT.
The overriding difference between the two groups of study participants is access to opportunities to exercise, Keith said. For patients at the CHC, there is generally no place for them to exercise. The cost of joining a fitness center is prohibitive for these patients, she added.
What is of great concern, Keith said, is that low levels of physical fitness are strongly related to negative health outcomes, including increased morbidity and mortality. The distinct differences among physical fitness levels between CHC patients and members of the medically affiliated fitness center demonstrate the clear need to identify low-cost and accessible means for vulnerable populations to improve their physical fitness levels, she said.
Access to health care for all populations is important, Keith said, but it is not enough if it doesn't include opportunities to exercise.
More about the study:
Coauthors of the study include Anthony S. Kaleth and Kyle McIlrath, IUPUI.
Public release date: 4-Jun-2011
Severity of facial wrinkles may predict bone density in early menopause
A news study finds that the worse a woman's skin wrinkles are during the first few years of menopause, the lower her bone density is. The results will be presented Monday at The Endocrine Society's 93rd Annual Meeting in Boston.
"In postmenopausal women the appearance of the skin may offer a glimpse of the skeletal well-being, a relationship not previously described," said Lubna Pal, MD, a reproductive endocrinologist and associate professor at Yale School of Medicine, New Haven, Conn.
The study demonstrates only an association between bone density and skin wrinkling, stressed Pal, the study's principal investigator. However, she called their findings noteworthy.
"This information," Pal said, "may allow for the possibility of identifying postmenopausal women at fracture risk at a glance, without dependence on costly tests."
The study is an ancillary study to an ongoing multicenter trial called the Kronos Early Estrogen Prevention Study, or KEEPS, which is funded by the Aurora Foundation and the Kronos Longevity Research Institute in Phoenix. This ancillary study included 114 women in their late 40s and early 50s who had had their last menstrual period within the past three years and who were not taking hormone therapy. Women were excluded from participating if they had undergone any cosmetic skin procedures.
Women received a score for face and neck wrinkles based on the number of sites with wrinkles and on the depth of the wrinkles. The skin firmness or rigidity was measured at the forehead and the cheek with a device called a durometer. Study participants also underwent measurement of bone density by dual X-ray absorptiometry (DEXA) and by a portable heel ultrasound device.
The investigators found a significant inverse correlation between the wrinkle score and the bone density, meaning the higher the score (and the worse the wrinkles), the lower the bone density. This relationship was evident at all skeletal sites—hip, lumbar spine and heel—and was independent of age, body composition or other factors known to influence bone density, Pal said. Additionally, firmer skin of the face and forehead was associated with greater bone density.
Although the connection between bones and skin may seem unclear, Pal explained that they share common building blocks—a group of proteins known as collagens. As we age, changes in collagen occur that may account for age related skin changes including worsening skin wrinkles and sagging skin, and also contribute to deterioration in bone quality and quantity.
Long-term studies are needed to substantiate a relationship between wrinkles and the risk of bone fracture, Pal said.
"Ultimately, we want to know if intensity of skin wrinkles can allow identification of women who are more likely to fracture a bone, especially the femoral neck or the hip, an often fatal injury in older people," she said. "If this is the case, then including the study of skin wrinkles to other clinical risk factors may allow identification of fracture risk in populations that do not have access to more costly technology."
Contact: Aaron Lohr
Public release date: 3-Jun-2011
New strain of MRSA discovered
Antibiotic resistant bacteria found in both humans and dairy cows
Scientists have identified a new strain of methicillin-resistant Staphylococcus aureus (MRSA) which occurs both in human and dairy cow populations.
The study, led by Dr Mark Holmes at the University of Cambridge, identified the new strain in milk from dairy cows while researching mastitis (a bacterial infection which occurs in the cows' udders).
The new strain's genetic makeup differs greatly from previous strains, which means that the 'gold standard' molecular tests currently used to identify MRSA - a polymerase chain reaction technique (PCR) and slide agglutination testing - do not detect this new strain. The research findings are published today in the journal The Lancet Infectious Diseases.
Dr Laura García-Álvarez, first author of the paper, who discovered the new strain while a PhD student at the University of Cambridge's Veterinary School, said: "To find the same new strain in both humans and cows is certainly worrying. However, pasteurization of milk will prevent any risk of infection via the food chain. Workers on dairy farms may be at higher risk of carrying MRSA, but we do not yet know if this translates into a higher risk of infection. In the wider UK community, less than 1% of individuals carry MRSA – typically in their noses – without becoming ill."
The scientists discovered the antibiotic resistant strain while researching S. aureus, a bacterium known to cause bovine mastitis. Despite the strain being able to grow in the presence of antibiotics, when they attempted to use the standard molecular tests available – which work by identifying the presence of the gene responsible for methicillin resistance (the mecA gene) - the tests came back negative for MRSA.
When Dr Matt Holden and a research team at the Wellcome Trust Sanger Institute sequenced the entire genome (decoding all of the genes in the bacteria's DNA) they realised that the new strain possessed unconventional DNA for MRSA. They found that the new strain does have a mecA gene but with only 60% similarity to the original mecA gene. Unfortunately, this results in molecular tests (which identify MRSA by the presence of the mecA gene) giving a false negative for this strain of MRSA.
Subsequent research revealed that the new strain was also present in humans. During the study, the new strain was found in samples from Scotland, England and Denmark (some from screening tests and others from people with MRSA disease). It has since been identified in Ireland and Germany. Additionally, by testing archived S. aureus samples, the researchers have also identified a recent upward trend in the prevalence of the antibiotic resistant bacteria.
Dr Mark Holmes said: "The majority of MRSA testing in British hospitals is performed by seeing if the bacteria will grow in the presence of antibiotics, typically oxacillin and cefoxitin, rather than methicillin - which is now no longer manufactured. This type of testing detects both the new MRSA and conventional MRSA.
"However, it is important that any of the MRSA testing that is based on detection of the mecA gene - i.e. PCR based testing, or slide agglutination testing - be upgraded to ensure that the tests detect the new mecA gene found in the new MRSA. We have already been working with public health colleagues in the UK and Denmark to ensure that testing in these countries now detects the new MRSA."
The new research also raises questions about whether cows could be a reservoir for the new strains of MRSA.
Dr Holmes added: "Although there is circumstantial evidence that dairy cows are providing a reservoir of infection, it is still not known for certain if cows are infecting people, or people are infecting cows. This is one of the many things we will be looking into next.
"Although our research suggests that the new MRSA accounts for a small proportion of MRSA – probably less than 100 isolations per year in the UK, it does appear that the numbers are rising. The next step will be to explore how prevalent the new strain actually is and to track where it is coming from. If we are ever going to address the problem with MRSA, we need to determine its origins."
Scientists at the Health Protection Agency (HPA) co-authored this paper, providing the analysis of the human samples of the new strain. Dr Angela Kearns, head of the HPA's Staphylococcus Reference Laboratory said: "There are numerous strains of MRSA circulating in the UK and the rest of Europe. Even though this new strain is not picked up by the current molecular tests, they do still remain effective for the detection of over 99 per cent of MRSAs. This new strain can be picked up by another type of test, which has shown to be effective in trials in the UK and elsewhere in Europe.
"This is a very interesting find and the HPA is currently involved in further research to screen a wider population of MRSA samples to ascertain how prevalent it is. It's important to remember MRSA is still treatable with a range of antibiotics and the risk of becoming infected with this new strain is very low."
With funding from the Medical Research Council, the researchers will next be undertaking prevalence surveys in people and in dairy cattle in the UK to determine how much new MRSA is present in these populations. They will also be performing an epidemiological study on farms to identify any factors that may be associated with infection by the new MRSA, to look for further new MRSA strains, and to explore the potential risks of the new strain to farm workers.
For additional information please contact:
Notes to editors:
1. The paper 'Meticillin-resistant Staphylococcus aureus with a novel mecA homologue emerging in human and bovine populations in the UK and Denmark: a descriptive study' will be published by The Lancet Infectious Diseases on Friday, 03 June.
2. The Health Protection Agency is an independent UK organisation that was set up by the government in 2003 to protect the public from threats to their health from infectious diseases and environmental hazards. It does this by providing advice and information to the general public, to health professionals such as doctors and nurses, and to national and local government. In 2012 the HPA will become part of Public Health England. To find out more, visit our website: www.hpa.org.uk
3. For almost 100 years the Medical Research Council has improved the health of people in the UK and around the world by supporting the highest quality science. The MRC invests in world-class scientists. It has produced 29 Nobel Prize winners and sustains a flourishing environment for internationally recognised research. The MRC focuses on making an impact and provides the financial muscle and scientific expertise behind medical breakthroughs, including one of the first antibiotics penicillin, the structure of DNA and the lethal link between smoking and cancer. Today MRC funded scientists tackle research into the major health challenges of the 21st century. www.mrc.ac.uk
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