Antibiotics that Kill Gut Bacteria also Stop Growth of Brain Cells

Antibiotics strong enough to kill off gut bacteria can also stop the growth of new brains cells in the hippocampus, a section of the brain associated with with memory, reports a study in mice published in Cell Reports on May 19. Researchers also uncovered a clue to why - a type of white blood cell seems to act as a communicator between the brain, the immune system and the gut.

Wolf first saw clues that the immune system could influence the health and growth of brain cells through research into T cells nearly 10 years ago. But there were few studies that found a link from the brain to the immune system and back to the gut.

In the study, the researchers gave a group of mice enough antibiotics for them to become nearly free of intestinal microbes, Compared to untreated mice, the mice who lost their healthy gut bacteria performed worse in memory tests and showed a loss of neurogenesis (new brain cells) in a section of their  hippocampus that typically produces new brain cells throughout an individual's lifetime. At the same time that the mice experienced memory and neurogenesis loss, the research team detected a lower level of white blood cells (specifically monocytes), marked with Ly6Chi in the brain, blood and bone marrow. So researchers tested whether it was indeed the Ly6Chi monocytes behind the changes in neurogenesis and memory. 

In another experiment, the team compared untreated mice to mice that had healthy gut bacteria levels but low levels of Ly6Chi either due to genetics or due to treatment with antibodies that target Ly6Chi cells. In both cases, mice with low Ly6Chi levels in mice treated with antibiotics, then memory and neurogenesis deficits as mice in the other experiment who had lost gut bacteria.Furthermore, if the researchers replaced the Ly6Chi levels in mice treated with antibiotics, them memory and neurogenesis improved.
Luckily, the adverse side effects of the antibiotics could be reversed. Mice who received probiotics or who exercised on a wheel after receiving antibiotics regained memory and neurogenesis.
Luckily, the adverse side effects of the antibiotics could be reversed. Mice who received probiotics or who exercised on a wheel after receiving antibiotics regained memory and neurogenesis.
But one result in the experiment raised more questions about the gut's bacteria and the link between Ly6Chi and the brain. While probiotics helped the mice regain memory, fecal transplants to restore a healthy gut bacteria did not have an effect.
In future, researchers also hope to see more clinical trails investigating whether probiotic treatments will improve symptoms in patients with neurodegenerative and psychiatric disorder.

Homosexuality as common in Uganda as elsewhere

Uganda has one of the harshest standpoint on homosexuality in the world. Homosexual acts are prohibited by law and have previously been suggested to warrant the death penalty. However a new study shows that homosexuality among young people is as common in Uganda as in other countries.

Sibling may be Good for Child's Health

According to a study, birth of a sibling , especially when the child was between 2 to 4 years old, was associated with a healthier body mass index (BMI) by first grade. Children the same age who did not have a sibling were nearly three times more likely to be obese by first grade. the finding includes 697 children across the U.S ., appear in the April 2016 issue of Pediatrics.

According to the author one possible explanation could be that parents may be change the way they feed their child once a new siblings born. With children developing long-lasting feeding habits at around three years old, changing dietary habits may have a significant impact.

Cytoskeletons shaking hands: Defects in cytoskeletal structures lead to various diseases

Animal cells harbor three types of cytoskeletal elements: actin filaments, intermediate filaments and microtubules. Despite their name, cytoskeletons are very dynamic structures, which undergo rapid reorganization in cells and thus contribute to numerous cellular processes, such as morphogenesis, motility, intracellular transport, and cell division. Consequently, defects in cytoskeletal structures lead to various diseases, including cancer and neurological disorders. 

Different cytoskeletal systems do not function in isolation, but collaborate with each other in cells. Post-doctoral researcher Yaming Jiu working at the Institute of Biotechnology, University of Helsinki has now revealed that cytoplasmic intermediate filaments interact with specific contractile actin filament structures called arcs.
"Actin arcs transport intermediate filaments from cell periphery toward the nucleus. Consequently, disruption of actin arcs led to an abnormal spreading of the intermediate filament network toward the cell periphery and associated defects in cell morphogenesis. Intermediate filaments resist the movement of arcs, and their depletion led to abnormalities in the shape of the arc-rich leading edge of motile cells," describes research director Pekka Lappalainen.

This story is taken from Science Daily

Microbiology: Gut bacteria cooperate when life gets tough

Researchers have discovered with the help of computer models how gut bacteria respond to changes in their environment -- such as a decrease in oxygen levels or nutrient availability. Microorganisms that normally compete or overthrow one another can switch to a cooperative lifestyle when their living conditions change: They even start producing substances to make life easier for the other species, helping them to survive. The entire microbial community then stabilizes -- and together adapts successfully to the new situation. 

The human gut is home to thousands of bacterial species, most of which have never been described in science. This ecosystem is a complex living community: The microorganisms live side-by-side, compete for nutrients, overthrow one another or even benefit off each other.
It is the aim of Almut Heinken, research associate in Ines Thiele's workgroup, to understand these interactions more completely: "For my thesis, I worked with data from literature and modelled on the computer how certain bacterial species respond to one another when the living conditions in their environment change," the scientist says. "Such models are a common method for making better predictions about the interactions of bacteria. We developed the method further and applied it for the first time to gut bacteria. With eleven species, we were able to calculate how they behave pairwise in the presence of human small intestinal cells."
Almut Heinken discovered some surprising types of behaviour in these studies: "Bacteria that are otherwise very dominant and overthrow other species suddenly enter a symbiosis with those same species if, for example, the oxygen content in the environment drops. They emit substances that make it easier for otherwise outcompeted species to survive. And they, too, receive substances they wouldn't get enough of under the unfavourable living conditions." Heinken has calculated such symbiotic behaviour for the bacterial species Lactobacillus plantarum, for example.
This turnaround in metabolism is vital for the bacterial community to continue functioning within the different sections of the gut: For example, the oxygen content varies in different places along the small intestine. There is more oxygen on the walls than in the centre, and more at the start of the small intestine than at its end. "By the bacteria mutually supporting one another when they find themselves in a low-oxygen environment, the bacterial community remains functional as a whole -- and so the digestion as well," Almut Heinken explains. The nutrient supply and the presence of sloughed intestinal cells also undergo great spatial variance, and have an influence on the symbiotic behaviour of the bacteria.
The LCSB researchers are interested above all in the importance of these bacterial interactions in relation to diseases, as Ines Thiele explains: "We know that diet and digestion can have an influence on the onset of diseases. This relates not only to the gastrointestinal tract, but also to other areas, such as the nervous system and its diseases, such as Parkinson's disease."
The scientists' long-term goal is therefore to understand the ecosystem of the gut in minutest detail. Accordingly, they are continually adding more bacterial species to their computer models. "If we manage to correlate certain responses of the bacterial community with the outbreak of diseases, then we will gain a powerful lever," Thiele says: "We would thereby create the opportunity to influence the disease preventatively or therapeutically by diet or by tweaking the gut flora using probiotics."

This story is taken from Science Daily

Why are 95% of people who live to 110 women? You're as old as your stem cells

Human supercentenarians share at least one thing in common--over 95 percent are women. Scientists have long observed differences between the sexes when it comes to aging, but there is no clear explanation for why females live longer. In a discussion of what we know about stem cell behavior and sex, researchers argue that it's time to look at differences in regenerative decline between men and women. This line of research could open up new explanations for how the sex hormones estrogen and testosterone, or other factors, modify lifespan. 

It's known that estrogen has direct effects on stem cell populations in female mice, from increasing the number of blood stem cells (which is very helpful during pregnancy) to enhancing the regenerative capacity of brain stem cells at the height of estrus. Whether these changes have a direct impact on lifespan is what's yet to be explored. Recent studies have already found that estrogen supplements increase the lifespan of male mice, and that human eunuchs live about 14 years longer than non-castrated males.

More work is also needed to understand how genetics impacts stem cell aging between the sexes. Scientists have seen that knocking out different genes in mice can add longevity benefits to one sex but not the other, and that males in twin studies have shorter telomeres--a sign of shorter cellular lifespan--compared to females.

"It is likely that sex plays a role in defining both lifespan and healthspan, and the effects of sex may not be identical for these two variables," the authors write. "As the search continues for ways to ameliorate the aging process and maintain the regenerative capacity of stem cells, let us not forget one of the most effective aging modifiers: sex."

This story is taken from Science Daily

Fine particulate air pollution linked to risk of childhood autism

Exposure to fine particulate air pollution during pregnancy through the first two years of the child's life may be associated with an increased risk of a child developing autism spectrum disorder, a condition that affects one in 68 children, according to an investigation of children in southwestern Pennsylvania.

The research is funded by The Heinz Endowments and published in the July edition of Environmental Research.
"Autism spectrum disorders are lifelong conditions for which there is no cure and limited treatment options, so there is an urgent need to identify any risk factors that we could mitigate, such as pollution," said lead author Evelyn Talbott, Dr.P.H., professor of epidemiology at Pitt Public Health. "Our findings reflect an association, but do not prove causality. Further investigation is needed to determine possible biological mechanisms for such an association."
Dr. Talbott and her colleagues performed a population-based, case-control study of families with and without ASD living in six southwestern Pennsylvania counties. They obtained detailed information about where the mothers lived before, during and after pregnancy and, using a model developed by Pitt Public Health assistant professor and study co-author Jane Clougherty, Sc.D., were able to estimate individual exposure to a type of air pollution called PM2.5.
This type of pollution refers to particles found in the air that are less than 2.5 micrometers in diameter, or 1/30th the average width of a human hair. PM2.5 includes dust, dirt, soot and smoke. Because of its small size, PM2.5 can reach deeply into the lungs and get into the blood stream. Southwestern Pennsylvania has consistently ranked among the nation's worst regions for PM2.5 levels, according to data collected by the American Lung Association.
"There is increasing and compelling evidence that points to associations between Pittsburgh's poor air quality and health problems, especially those affecting our children and including issues such as autism spectrum disorder and asthma," said Grant Oliphant, president of The Heinz Endowments. "While we recognize that further study is needed, we must remain vigilant about the need to improve our air quality and to protect the vulnerable. Our community deserves a healthy environment and clean air."
Autism spectrum disorders are a range of conditions characterized by social deficits and communication difficulties that typically become apparent early in childhood. Reported cases of ASD have risen nearly eight-fold in the last two decades. While previous studies have shown the increase to be partially due to changes in diagnostic practices and greater public awareness of autism, this does not fully explain the increased prevalence. Both genetic and environmental factors are believed to be responsible.
Dr. Talbott and her team interviewed the families of 211 children with ASD and 219 children without ASD born between 2005 and 2009. The families lived in Allegheny, Armstrong, Beaver, Butler, Washington and Westmoreland counties. Estimated average exposure to PM2.5 before, during and after pregnancy was compared between children with and without ASD.
Based on the child's exposure to concentrations of PM2.5 during the mother's pregnancy and the first two years of life, the Pitt Public Health team found that children who fell into higher exposure groups were at an approximate 1.5-fold greater risk of ASD after accounting for other factors associated with the child's risk for ASD -- such as the mother's age, education and smoking during pregnancy. This risk estimate is in agreement with several other recent investigations of PM2.5 and autism.
A previous Pitt Public Health analysis of the study population revealed an association between ASD and increased levels of air toxics, including chromium and styrene. Studies by other institutions using different populations also have associated pollutants with ASD.
"Air pollution levels have been declining since the 1990s; however, we know that pockets of increased levels of air pollution remain throughout our region and other areas," said Dr. Talbott. "Our study builds on previous work in other regions showing that pollution exposures may be involved in ASD. Going forward, I would like to see studies that explore the biological mechanisms that may underlie this association."

This story is taken from Science Daily

Study finds 63% of women report sexual problems, with orgasm proving biggest issue in teens and 20s

Almost two-thirds of females attending a general urology practice said they suffered from sexual dysfunction. Dysfunction rose with age in all categories except orgasm, with 54% of women aged from 18 to 30 reporting orgasm problems, significantly higher than women aged 31 to 45 (43%) and women aged 46 to 54 (48%). Researchers asked 587 women aged from 18 to 95, attending a urology clinic in New Jersey, USA, about six key areas of female sexual dysfunction (FSD): lack of desire, arousal issues, lack of lubrication, problems achieving orgasm, lack of satisfaction and pain during intercourse. They found that that 63% suffered from FSD and that there were significant links between FSD and age, menopausal status and use of selective antidepressants.

Dysfunction rose with age in all categories except orgasm, with more than half of women aged from 18 to 30 reporting orgasm problems, significantly higher than women aged 31 to 54.
Researchers asked 587 women aged from 18 to 95, who attended a urology clinic in New Jersey, about six key areas of female sexual dysfunction (FSD): lack of desire, arousal issues, lack of lubrication, problems achieving orgasm, lack of satisfaction and pain during intercourse.
"We found that 63% of the women suffered from FSD and that there were significant links between FSD and age, menopausal status and use of selective antidepressants" says co-author Dr Debra Fromer, head of the Center for Bladder, Prostate and Pelvic Floor Health at Hackensack University Medical Center, New Jersey.
Twelve per cent of the women who took part in the study were aged 18-30, 27% were 31-45, 25% were 46-54, 24% were 55-70 and 12% were 70 plus.
They attended a typical American metropolitan urology practice caring for conditions such as urinary incontinence, urinary tract infections, pelvic floor problems and kidney stones.
Key findings of the survey included:

• The most sexually active age groups were 31-45 year-olds (87%), 18-30 year-olds (85%) and 46-54 year-olds (74%). It then fell sharply in 55-70 year-olds (45%) and in women who were over 70 (15%).
• The top overall problem was lack of desire (47%), followed by orgasm problems (45%), arousal issues (40%), lack of satisfaction (39%), lack of lubrication (37%) and pain (36%).
• Five of the six categories increased as the women got older: desire from 36 to 96%, arousal from 27 to 54%, lubrication from 26 to 45%, satisfaction from 28 to 88% and pain from 10 to 56%.
• The only category that bucked the trend was orgasm, with problems higher in the 18-30 age group (54%) than in the 31-45 (43%) and 46-54 (48%) age groups. It then rose to 66% at 55-70 and 87% when women were over 70.

The top three problems by age group were:

• 18-30: orgasm (54%), desire (36%) and satisfaction (28%)
• 31-45: desire (48%), orgasm (43%) and satisfaction (40%)
• 46-54: desire (65%), satisfaction (53%) and orgasm (48%)
• 55-70: desire (77%), orgasm (66%), satisfaction (65%)
• Over 70: desire (96%), satisfaction (88%) and orgasm (87%).

"FSD can have a major effect on women's quality of life," says Dr Fromer. "Self-esteem, sense of wholeness and relationships can be seriously and adversely affected, exacting a heavy emotional toll.
"Researchers have found significant associations between major categories of sexual dysfunction, reduced physical and emotional satisfaction and general well-being.
"That is why it is so important to ensure that problems are identified and tackled wherever possible. For example a number of hormone and other drug treatments have been shown to benefit women with FSD."
Known risk factors for FSD include age, a history of sexual abuse or sexually transmitted infections, depression, lower socioeconomic status, lifestyle, overall physical health and sexual experience.
"Interestingly, our study found very similar levels of dysfunction to an age-matched Turkish study," adds Dr Fromer. "This suggests a biological cause for FSD rather than societal or cultural factors, although they make some contribution to certain psychological aspects of the disorder."

This story is taken from Science Daily

Sexual satisfaction in women increases with age

A new study of sexually active older women has found that sexual satisfaction in women increases with age and those not engaging in sex are satisfied with their sex lives. A majority of study participants report frequent arousal and orgasm that continue into old age, despite low sexual desire.

The study appears in the January issue of The American Journal of Medicine.

Researchers from the University of California, San Diego School of Medicine and the Veterans Affairs San Diego Healthcare System evaluated sexual activity and satisfaction as reported by 806 older women who are part of the Rancho Bernardo Study (RBS) cohort, a group of women who live in a planned community near San Diego and whose health has been tracked for medical research for 40 years. The study measured the prevalence of current sexual activity; the characteristics associated with sexual activity including demographics, health, and hormone use; frequency of arousal, lubrication, orgasm, and pain during sexual intercourse; and sexual desire and satisfaction in older women.

The median age in the study was 67 years and 63% were postmenopausal. Half the respondents who reported having a partner had been sexually active in the last 4 weeks. The likelihood of sexual activity declined with increasing age. The majority of the sexually active women, 67.1%, achieved orgasm most of the time or always. The youngest and oldest women in the study reported the highest frequency of orgasm satisfaction.

40% of all women stated that they never or almost never felt sexual desire, and one third of the sexually active women reported low sexual desire. Lead investigator Elizabeth Barrett-Connor, MD, Distinguished Professor and Chief, Division of Epidemiology, Department of Family and Preventive Medicine, University of California, San Diego School of Medicine, comments, "Despite a correlation between sexual desire and other sexual function domains, only 1 in 5 sexually active women reported high sexual desire. Approximately half of the women aged 80 years or more reported arousal, lubrication, and orgasm most of the time, but rarely reported sexual desire. In contrast with traditional linear model in which desire precedes sex, these results suggest that women engage in sexual activity for multiple reasons, which may include affirmation or sustenance of a relationship."

Regardless of partner status or sexual activity, 61% of all women in this cohort were satisfied with their overall sex life. Although older age has been described as a significant predictor of low sexual satisfaction, the percentage of RBS sexually satisfied women actually increased with age, with approximately half of the women over 80 years old reporting sexual satisfaction almost always or always. Not only were the oldest women in this study the most satisfied overall, those who were recently sexually active experienced orgasm satisfaction rates similar to the youngest participants. "In this study, sexual activity was not always necessary for sexual satisfaction. Those who were not sexually active may have achieved sexual satisfaction through touching, caressing, or other intimacies developed over the course of a long relationship," says first author Susan Trompeter, MD, Associate Clinical Professor of Medicine. Division of General Internal Medicine, Department of Medicine at the University of California, San Diego School of Medicine and Staff Physician at the VA San Diego Healthcare System.

"Emotional and physical closeness to the partner may be more important than experiencing orgasm. A more positive approach to female sexual health focusing on sexual satisfaction may be more beneficial to women than a focus limited to female sexual activity or dysfunction," Trompeter concludes

Sexual risk reduction intervention more effective for adolescent boys than girls, new research shows

Nearly half of high school students in the U.S. have had sexual intercourse and one third did not use a condom during their last sexual encounter, this study examined whether an intensive theory-driven intervention would prevent sexual risk behavior in young adolescents.

"We know that nearly half of high school students in the U.S. have had sexual intercourse and one third did not use a condom during their last sexual encounter," said Laurie J. Bauman, Ph.D., professor of pediatrics and director, Preventive Intervention Research Center, Albert Einstein College of Medicine, and director of research, Montefiore School Health Program. "Previous interventions have been tested to reduce risk, but have typically targeted older youth and have shown mixed results. Our study investigated the effects of an intensive theory-driven intervention designed to prevent sexual risk behavior in young adolescents."
A total of 400 Bronx-based adolescent patients from Montefiore were randomly assigned to intervention or control groups. Both groups received a 14 session intervention over a seven week period. The intervention group, called Project Prepared, did interactive exercises that addressed risk behavior, abstinence, HIV/STI knowledge, correct condom use, peer pressure and understanding relationships. The control group, called TEEN, did not receive this sexual risk reduction content, instead receiving peer counseling and education about self-esteem, communication and mental health.
Data were collected at baseline and six and twelve months later. Analyses show that there were no significant differences between the groups at baseline, but six months post-baseline boys who were randomized to Project Prepared had improved HIV knowledge and improved abstinence self-efficacy compared to boys who were randomized to the TEEN intervention. However, 12 months post-baseline the effects had diminished. Interestingly, girls showed no benefit from the intervention.
"Further study is needed to determine why the intervention wasn't effective for girls, but anecdotally, we have heard that many girls believe if a condom is used during sexual intercourse, the partner doesn't believe she is 'the one,'" said Dr. Bauman. "Ongoing intervention, education, and developmentally-appropriate guidance are required to maintain the positive impact that can be achieved for boys and support both boys and girls through different situations over time."

This story is taken from Science Daily