Spread your sperm the smart way
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Attractive males release fewer sperm per mating to maximise their chances of producing offspring across a range of females, according to a new paper on the evolution of ejaculation strategies. The findings by researchers at UCL (University College London) and the University of Oxford suggest that, paradoxically, matings with attractive males may be less fertile than those with unattractive ones.
In a paper to be published in the journal American Naturalist, the team mathematically modelled a range of male ejaculation strategies to look for the optimum “sperm load” per mating, and how this might vary depending on mating patterns. Previous studies have shown that in animals such as the domestic fowl, and fish such as the Arctic charr, males with privileged access to females produce ejaculates of lower fertilising quality than subordinate males.
Sam Tazzyman, UCL CoMPLEX (Centre for Mathematics and Physics in the Life Sciences and Experimental Biology), says: “In some species, females mate with many different males. Each male’s sperm competes with that of other males in a process known as ‘sperm competition’. Since males have finite resources to allocate to breeding, they allocate them carefully to each mating to maximise their number of offspring. If a male puts a lot of resources into each mating he will get more offspring per mating, but at the expense of fewer matings. If, on the other hand, a male puts few resources into each mating he will secure less paternity per mating, but will be able to carry out more matings overall. Thus, there is a trade-off between number of matings and success per mating.”
Teens’ drinking linked to mental health problems
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Teenagers who drink heavily are also more likely than their peers to have behavioral problems or symptoms of depression and anxiety, a new study finds.
The study, of nearly 9,000 Norwegian teenagers, found that those who said they had been drunk more than 10 times in their lives were more likely to have attention and conduct problems in school. Meanwhile, heavy-drinking girls showed higher rates of depression and anxiety symptoms.
The findings, published in the online journal Child and Adolescent Psychiatry and Mental Health, are based on a one-time survey. They do not, therefore, show whether the drinking came before or after the teenagers’ other problems.
Pigs at risk from people as new flu spreads
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There is a growing risk that pigs will catch the new H1N1 flu strain—commonly known as swine flu—from humans, German researchers said on Thursday.
Widespread transmission from people to pigs could mix up virus strains further, leading to unpredictable changes in the disease.
There have already been a handful of suspected cases of humans passing the current pandemic H1N1 virus to swine. The latest German research confirms it is infectious to pigs and can spread rapidly.
Number of US preterm, low birth weight babies down
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The encouraging news: After several decades of steady increases, the percentages of infants born preterm and the percentage born with low birth weight declined slightly in 2007 in the US, according to a report released today.
The bad news: In 2007, 18% of all US children ages 0 to 17 lived in poverty, up from 17% the year before, Dr. Duane Alexander, Director of Eunice Kennedy Shriver National Institute of Child Health and Human Development, noted at a telebriefing describing highlights of the US government’s annual report on the well-being of American children.
“Infants born preterm and of low birth weight are at increased risk for infant death and they also have a greater chance of lifelong disabilities such as blindness, deafness and cerebral palsy, making this an extremely important indicator of child well-being,” Alexander noted.
Mom’s drug use tied to child-abuse risk
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Young children whose mothers abuse drugs may face a higher risk of abuse and placement in foster care, a new study finds.
Australian researchers found that infants whose mothers abused amphetamines or opiates such as heroin were 13 times more likely to become victims of neglect or abuse than other children their age. Their odds of being placed in foster care were similarly elevated, according to findings published in the journal Pediatrics.
Using data from child-protection services, Andrea McGlade of the Royal Children’s Hospital in Brisbane and her colleagues found that half of the children born to drug-abusing mothers became victims of neglect or physical, emotional or sexual abuse.
Study Identifies Potential Fix for Damaged Knees
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Investigators from Hospital for Special Surgery have shown that a biodegradable scaffold or plug can be used to treat patients with damaged knee cartilage. The study is unique in that it used serial magnetic resonance imaging (MRI) and newer quantitative T2 mapping to examine how the plug incorporated itself into the knee. The research, abstract 8372, will be presented during the annual meeting of the American Orthopedic Society for Sports Medicine, July 9-12, in Keystone, Colo.
“The data has been encouraging to support further evaluation of this synthetic scaffold as a cartilage repair technique,” said Asheesh Bedi, M.D., a fellow in sports medicine and shoulder surgery at Hospital for Special Surgery who was involved with the study. Dr. Bedi performed analysis of MRI scans of patients primarily treated by Riley Williams, M.D., director of the Institute for Cartilage Repair at Hospital for Special Surgery. “The Trufit plug has been designed to have mechanical properties that are similar to cartilage and bone,” Dr. Bedi said.
Damage to so-called articular cartilage can occur in various ways, ranging from direct trauma in a motor vehicle accident to a noncontact, pivoting event on the soccer field. “Articular cartilage lacks the intrinsic properties of healing—you are essentially born with the articular cartilage that you have,” Dr. Bedi said. Left untreated, these injuries can increase loads placed on the remaining intact cartilage and increase the risk of progression to degenerative arthritis. One way to treat patients with symptomatic chondral lesions is an OATS procedure, in which cartilage is transferred from one portion of the knee to treat another. Because this is a “robbing Peter to pay Paul” situation, researchers at Hospital for Special Surgery set out to examine whether they could use a biodegradable plug, the Trufit CB plug, to fill the donor site. The goal was to monitor how the plug incorporated itself into the knee and to evaluate the quality of the repair cartilage.
Two Reproductive Factors are Important Predictors of Death from Ovarian Cancer
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Researchers from the Centers for Disease Control and Prevention (CDC) found that survival among women with ovarian cancer is influenced by age of menarche and total number of lifetime ovulatory cycles.
This finding suggests that hormonal activity over the course of a woman’s lifetime may influence the prognosis after an ovarian cancer diagnosis. Results of this study are published in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.
Results of previous studies indicated that fewer lifetime ovulatory cycles, higher parity, oral contraceptive use, hysterectomy and tubal ligation are associated with decreased risk of developing this form of cancer, according to the researchers. However, little is known about the influence of these factors on a patient’s survival after a diagnosis of ovarian cancer.
Health Clinic Conditions May Be to Blame for Decrease in Primary Care Physicians
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Adverse work conditions may be to blame for the decline in the number of primary care physicians nationwide, according to a study published in the latest issue of the Annals of Internal Medicine.
“Unfavorable work conditions are associated with stress, burnout and intent to leave for primary care physicians,” said Dr. Anita Varkey, study author and assistant professor in the department of medicine, Loyola University Chicago Stritch School of Medicine. “These factors contribute to poor job satisfaction, which is among the reasons we are seeing a decrease in the number of primary care physicians.”
The Association of American Medical Colleges estimates that the overall shortage of doctors may grow to 124,400 by 2025.
“There are not enough primary care physicians to meet current needs,” said Varkey, who also is medical director of the general medicine clinic at Loyola Outpatient Center, Loyola University Health System. “These findings suggest that a chaotic clinic environment may further exacerbate this problem and potentially lead to lower quality of patient care due to physician turnover and lack of continuity in care.”
Why African-Americans Fare Worse with Some Cancers
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An analysis of almost 20,000 patient records from the Southwest Oncology Group’s database of clinical trials finds, for the first time, that African-American breast, ovarian, and prostate cancer patients tend to die earlier than patients of other races even when they get identical medical treatment and other confounding socioeconomic factors are controlled for. The finding points to biological or host genetic factors as the potential source of the survival gap.
“When you look at the dialogue about the issue of race and cancer survival that’s gone on over the years,” says the paper’s lead author, Kathy Albain, M.D., a breast and lung cancer specialist at Loyola University’s Cardinal Bernardin Cancer Center, “it always seems to come down to general conclusions that African-Americans may in part have poorer access to quality treatment, may be diagnosed in later stages, and may not have the same standard of care delivered as Caucasian patients, leading to a disparity in survival.”
The study, which will be published online by the Journal of the National Cancer Institute (JNCI) on July 7, found that when treatment was uniform and differences in tumor prognostic factors, demographics, and socioeconomic status were controlled, there was in fact no statistically significant difference in survival based on race for a number of other cancers—lung, colon, lymphoma, leukemia, and multiple myeloma.
New heart disease risk score outperforms existing test
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An independent external validation of QRISK® — a new score for predicting a person’s risk of heart disease — has shown that it performs better than the existing test and should be recommended for use in the United Kingdom by the National Institute for Health and Clinical Excellence (NICE).
The University of Nottingham and leading healthcare systems supplier EMIS worked together, through the not-for-profit partnership QResearch, to develop the ground-breaking formula which has been strongly endorsed in new research published in the British Medical Journal.
Researchers from the University of Oxford have recommended its widespread use across the UK in place of the more commonly-used Framingham equation.
Obama administration takes action on food safety
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The Obama administration on Tuesday ordered tougher steps to curb Salmonella and Escherichia coli contamination in U.S. food processing plants and created a new deputy food commissioner post to coordinate safety in the wake of a Salmonella outbreak.
The administration, concerned by delays in identifying the source of the salmonella contamination that sickened more than 700 people in 46 states earlier this year, also moved to create a better tracing system for identifying the origin of foodborne illnesses.
The actions, to be unveiled by the administration at an event on Tuesday, were based on recommendations from a Food Safety Working Group created by President Barack Obama in March after a Salmonella outbreak in peanut products forced the largest food recall in U.S. history.
Die-hard Cypriot smokers must stub out by Jan 1
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Die-hard smokers in Cyprus will finally have to curb the habit when one of the last EU smoking havens imposes a Jan. 1 ban on puffing in public places.
Lawmakers are poised to pass tough new regulations banning smoking in public places, replacing an existing law which is regularly flouted.
Come Jan. 1, smoking will be prohibited in restaurants, bars, nightclubs and workplaces, with planned hefty fines for those caught having a puff.
Age not linked to Achilles pain in older athletes
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Age does not seem to play a role in the development of Achilles tendon problems among older athletes, nor do training and participation in walking, jumping, sprinting, running, or hurdling competitions, findings from a European study suggest.
Achilles tendon pain results from swelling or tiny tears in the tendon that connects the calf muscle to the heel bone. The exact cause of this “overuse” injury, characterized by swelling or mild to severe pain when rising onto the toes or pushing off when walking, is unknown.
The current study, reported in The American Journal of Sports Medicine, involved 110 men and 68 women who were highly trained, competitive track and field athletes participating in the European Veterans Athletics Championships held in Poland in July 2006.
New culprit behind obesity’s ill metabolic consequences
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Obesity very often leads to insulin resistance, and now researchers reporting in the July 8 issue of Cell Metabolism, a Cell Press publication, have uncovered another factor behind that ill consequence. The newly discovered culprit—a protein known as pigment epithelium-derived factor (PEDF for short)—is secreted by fat cells. They also report evidence to suggest that specifically blocking that protein’s action may reverse some of the health complications that come with obesity.
“With obesity, PEDF release is increased from fat, leading to higher levels of PEDF in the bloodstream,” said Matthew Watt of Monash University in Australia. “PEDF sends a signal to other body tissues, causing insulin resistance in muscle and liver, a major defect that leads to the development of type 2 diabetes.”
Elevated PEDF is also associated with increased release of fatty acids from fat stores, which causes blood lipid levels to rise. That “dyslipidemia” may be associated with other complications including cardiovascular disease.
Severe COPD may lead to cognitive impairment
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Severe chronic obstructive pulmonary disease (COPD) is associated with lower cognitive function in older adults, according to research from Mount Sinai School of Medicine. Researchers compared cognitive performance in over 4,150 adults with and without COPD and found that individuals with severe COPD had significantly lower cognitive function than those without, even after controlling for confounding factors such as comorbidities.
The results were published in the July 15 issue of the American Journal of Respiratory and Critical Care Medicine.
“Our findings should raise awareness that adults with severe COPD are at greater risk for developing cognitive impairment, which may make managing their COPD more challenging, and will likely further worsen their general health and quality of life,” wrote lead author of the study, William W. Hung, M.D., M.P.H., assistant professor at Mount Sinai School of Medicine.
