25.12.2010

Эхинацея и гинкго - почти плацебо?

Об эхинацеи читаем на http://blisstree.com/feel/echinacea-doesnt-cure-colds/ :
Trying to cure your pre-Christmas cold with all-natural Echinacea? A new study suggests that the so-called wonder herb, that’s been purported to prevent colds, may not be a miracle worker after all. It seems the herb, which is a wild flower found in the Midwestern plains, doesn’t have much impact on the duration or strength of colds.
The study followed more than 700 cold sufferers, and found that people who took Echinacea saw around a 10% reduction in the duration of their cold. That ends up being about seven to ten fewer hours, which is not, according to lead researcher Bruce Barrett, considered a medically significant decrease.
But Barrett advised that people who’ve experienced Echinacea’s healing properties should continue taking it, since the study isn’t absolutely conclusive. Besides, if you think it’s helping, than there’s no harm in trying, right?

О гинкго - на http://www.science20.com/news_articles/ginkgo_biloba_has_no_impact_cognitive_decline:
Ginkgo biloba, popularly consumed for its supposedly positive effect on memory, has no such effect, according to new research published in the December 23/30 issue of JAMA.  In the study, older adults who used the herbal supplement  for several years did not have a slower rate of cognitive decline compared to adults who received placebo .

"Ginkgo biloba is marketed widely and used with the hope of improving, preventing, or delaying cognitive impairment associated with aging and neurodegenerative disorders such as Alzheimer disease," the authors write. "Indeed, in the United States and particularly in Europe, G biloba is perhaps the most widely used herbal treatment consumed specifically to prevent age-related cognitive decline." However, evidence from large clinical trials regarding its effect on long-term cognitive functioning is lacking.

Beth E. Snitz, Ph.D., of the University of Pittsburgh, and colleagues analyzed outcomes from the Ginkgo Evaluation of Memory (GEM) study to determine if G biloba slowed the rate of cognitive decline in older adults who had normal cognition or mild cognitive impairment (MCI) at the beginning of the study.

The GEM study previously found that G biloba was not effective in reducing the incidence of Alzheimer dementia or dementia overall. The randomized, double-blind, placebo-controlled clinical trial included 3,069 community-dwelling participants, ages 72 to 96 years, who received a twice-daily dose of 120-mg extract of G biloba (n = 1,545) or identical-appearing placebo (n = 1,524). The study was conducted at six academic medical centers in the United States between 2000 and 2008, with a median (midpoint) follow-up of 6.1 years. Change in cognition was assessed by various tests and measures.

In this study, the largest randomized controlled trial of G biloba to report on outcomes to date, the researchers found no evidence for an effect of G biloba on global cognitive change and no evidence of effect on specific cognitive domains of memory, language, attention, visuospatial abilities and executive functions. They also found no evidence for differences in treatment effects by age, sex, race, education or baseline cognitive status (MCI vs. normal cognition).

"In sum, we find no evidence that G biloba slows the rate of cognitive decline in older adults. These findings are consistent with previous smaller studies examining prevention of decline and facilitation of cognitive performance and with the 2009 Cochrane review of G biloba for dementia and cognitive impairment."

Citation: Beth E. Snitz, Ellen S., Michelle C. Carlson, Alice M. Arnold, Diane G. Ives, Stephen R. Rapp, Judith Saxton, Oscar L. Lopez, Leslie O. Dunn, Kaycee M. Sink, Steven T. DeKosky, 'Ginkgo biloba for Preventing Cognitive Decline in Older Adults', JAMA, 2009, 302(24), 2663-2670

04.11.2010

Ряд новых интересностей о допамине :)

Dopamine model could play role in treating schizophrenia and drug addiction


In the brain, dopamine is involved in a number of processes that control the way we behave. If an action results in the substance being released, we are more likely to repeat the action. This applies to actions such as eating, sexual intercourse or winning a competition. However, the same also holds true when individuals take harmful narcotics. Scientists believe that mental illnesses such as schizophrenia can be linked to dopamine imbalances. Дальше на http://www.eurekalert.org/pub_releases/2010-10/uoc-dmc102010.php


Montreal, October 20, 2010 – Daily sleeping and eating patterns are critical to human well-being and health. Now, a new study from Concordia University has demonstrated how the brain chemical dopamine regulates these cycles by altering the activity of the "clock-protein" PER2. Published in the Journal of Neuroscience, these findings may have implications for individuals with Parkinson's Disease with disrupted 24-hour rhythms of activity and sleep. Дальше http://www.eurekalert.org/pub_releases/2010-10/cu-nro102010.php


SEATTLE, Wash. — October 18, 2010 — Researchers at the Allen Institute for Brain Science have found that the same genes have different activity patterns in the brain in individuals with different genetic backgrounds. These findings may help to explain individual differences in the effectiveness and side-effect profiles of therapeutic drugs and thus have implications for personalized medicine. The study is available in this week’s online early edition of the Proceedings of the National Academy of Sciences  Дальше http://scienceblog.com/39433/gene-activity-in-the-brain-depends-on-genetic-background/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+scienceblogrssfeed+%28Science+Blog%29

Sensation seeking—the urge to do exciting things—has been linked to dopamine, a chemical that carries messages in your brain. For a new study published in Psychological Science, a journal of the Association for Psychological Science, scientists analyzed genes in the dopamine system and found a group of mutations that help predict whether someone is inclined toward sensation seeking. Дальше http://scienceblog.com/39121/a-thirst-for-excitement-is-hidden-in-your-genes/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+scienceblogrssfeed+%28Science+Blog%29


Glutamate and dopamine: Biological predictors of the transition to psychosis?


Philadelphia, PA, 30 September, 2010 - There is growing evidence that two neurotransmitters - dopamine and glutamate - are abnormal in people with psychotic illness, including schizophrenia. Among many other things, these chemicals play a role in cognitive functions, such as memory, learning, and problem-solving
A new study in Biological Psychiatry is now the first to examine the relationship between these two brain chemicals by measuring both in the same individuals. http://www.eurekalert.org/pub_releases/2010-09/e-gd093010.php


There’s a predictable narrative to a lot of discoveries in molecular biology. The story begins when a scientist discovers that Molecule X causes Phenomenon Y. Perhaps we’re talking about CREB and long-term memory, or serotonin and depression, or cholesterol and heart disease. At first, the data looks really solid – when the gene for Molecule X is knocked out of a mouse, Phenomenon Y disappears! And when patients take a drug that increases/reduces Molecule X, you get a change in Phenomenon Y! The causal relationship seems so simple.


And that’s when things start to get complicated. Time and time again, the neat relationship between Molecule X and Phenomenon Y disintegrates into a knot of feedback loops, enzymatic pathways, environmental interactions and regulatory genes. It’s not that Molecule X doesn’t matter – it’s that it doesn’t exist by itself. Instead, the Molecule exerts its effects by interacting with a byzantine list of other molecules, all of which can also influence the biological outcome. Read More http://www.wired.com/wiredscience/2010/08/sex-is-stressful-but-good-for-you/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+wiredscience+%28Blog+-+Wired+Science%29

10.09.2010

Всем жениться!11111111

Оказывается, женитьба - это не только приятно, но и очень полезно для здоровья. Вот вам и очередное доказательство. Читаем на http://scienceblog.com/37587/marriage-and-committed-romance-reduce-stress-related-hormone-production/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+scienceblogrssfeed+%28Science+Blog%29
Being married has often been associated with improving people’s health, but a new study suggests that having that long-term bond also alters hormones in a way that reduces stress.


Unmarried people in a committed, romantic relationship show the same reduced responses to stress as do married people, said Dario Maestripieri, Professor in Comparative Human Development at the University of Chicago and lead author of the study, published in the current issue of the journal Stress.

“These results suggest that single and unpaired individuals are more responsive to psychological stress than married individuals, a finding consistent with a growing body of evidence showing that marriage and social support can buffer against stress,” Maestripieri writes in the article, “Between- and Within-sex Variations in Hormonal Responses to Psychological Stress in a Large Sample of College Students.”

The team of researchers from the University of Chicago and Northwestern University studied 500 masters’ degree students at the University of Chicago Booth School of Business. About 40 percent of the men and 53 percent of the women were married or in relationships. The group included 348 men with a mean age of 29 and 153 women with a mean age of 27.

The students were asked to play a series of computer games that tested economic behaviors, and saliva samples were taken before and after to measure hormone levels and changes.

Each student was told that the test was a course requirement, and it would impact their future career placement. That made the test a potentially stressful experience that could affect levels of cortisol, known as the stress hormone.

The researchers found cortisol concentrations increased in all participants, but that females experienced a higher average increase than males. The exercise also decreased testosterone in male subjects, but not in females, a stress effect previously observed in humans and animals.

But a piece of personal information collected before the test provided another interesting difference within the subjects. “We found that unpaired individuals of both sexes had higher cortisol levels than married individuals,” Maestripieri said.

“Although marriage can be pretty stressful, it should make it easier for people to handle other stressors in their lives,” Maestripieri said. “What we found is that marriage has a dampening effect on cortisol responses to psychological stress, and that is very new.”

The study also found that single business school students also displayed higher baseline testosterone levels than their married or committed colleagues, a finding that mirrors previous human research as well as animal observations.
Maestripieri, who conducts the majority of his research on monkeys in Puerto Rico, said that in species of primates and birds where males assist females with rearing offspring show similar changes. In species that show monogamous pairing and shared rearing of offspring, testosterone levels in males drop as they engage in more fatherly behavior.

Maestripieri’s co-authors are Nicole Baran, a University of Chicago graduate who is now graduate student at Cornell University; Luigi Zingales, the Robert C. McCormack Professor of Entrepreneurship and Finance, University of Chicago Booth School of Business; and Paola Sapienza, Professor of Finance at Northwestern’s Kellogg School of Management.

26.07.2010

Экстази как лекарство

Два хороших поста о клинических испытаниях использования МДМА в качестве лекарства при посттравматическом синдроме. Очень совеитую почитать:

The media coverage of the MDMA Clinical trial result stinks

MDMA for PTSD: The first peer-reviewed clinical trial report

21.07.2010

Когнитивные стимуляторы

Обожаю эту девочку. У неё самые весёлые посты о самых интересных веществах. Очередная классная статья - http://scienceblogs.com/neurotopia/2010/07/prozac_ritalin_cognitive_enhan.php. О "улучшителях умственных способностей". Особое внимание уделено Прозаку и Риталину.

О процессах ингибирования в мозгу

Дым сигарет с ментолом

Интересная инфа о влиянии ментола на "привыкабельность":
Cigarettes are just plain bad, as we all know by now.
But what about the ones that contain menthol? Are they worse?
A panel of experts is mulling menthol and trying to come up with some advice for the Food and Drug Administration on whether menthol should be forbidden as an additive.
Young people seem to gravitate to menthol-flavored cigarettes, and there's evidence menthol may make it harder for smokers trying to quit. It turns out that tiny amounts of menthol are even added as a subtle flavor-enhancer to many cigarettes that aren't labeled as menthol types.
Should menthol be banned —- just as Congress has banned other flavorings in cigarettes? Tobacco industry representatives say taste is the only thing that distinguishes menthol cigarettes from regular one — they aren't more harmful.
The use of menthol started accidentally, after mint crystals got left in a smoker’s tin of rolling tobacco overnight years ago.
The mint in menthol cigarettes may be natural or synthetic or a combination of both. Natural mint is crystalized from steamed distilled oil of the corn mint plant. Some 99 percent of the mint comes through in the smoke.
So how does the stuff get put on cigarettes? A bunch of ways. Sometimes, it's applied to the foil that is used to wrap the cigarettes. It's also sprayed on the tobacco, and even injected into the tobacco paper or the filter.
After a few weeks for aging, Michael Ogden of R.J. Reynolds says the effect was found to be the same pretty much regardless of method, according to smokers who volunteered for taste tests.
Ogden says testers describe the menthol smokes using terms like "cooling sensation, minty flavor and medicinal flavor."
Menthol can be misleading. "Menthol leads to the perception of an increase in nasal airway openness but in fact there is no actual change and (some studies have shown) minor constriction," Ogden says
R.J. Reynolds is the maker of Kool and Salem, once the leading menthol brands. Now, Newport dominates the market. It's from Lorillard, whose Scientific Director William True can sound like someone on Top Chef when he describes how the company assesses menthol.
True says the company taste experts sample packs the way some people test fine wine. They are sensitive to such things as a cigarette's early draw, the tobacco's papery or woody flavors, whether it's bitter or sweet, has a later draw or an after taste.
But it isn't menthol's taste that is under scrutiny at the hearing.
The scientific advisory panel wanted to know what properties in mentholated cigarettes attract young people, African Americans, and other ethnic groups. Newport is the top menthol cigarette for adolescents, according to the federal Substance Abuse & Mental Health Services Administration. The thinking is that menthol mellows the harshness of tobacco, which makes it easier for initiates to inhale and others to inhale more deeply.
True objected strenuously. "Absolutely not," he says. "Our product developers do not use menthol in any shape or form to cover, mask or minimize that harsh taste. The most significant items that impact the harsh taste of the cigarette are the tobacco blend, the moisture level of the blend and the filter ventilation."
The manufacturers of menthol cigarettes also deny that young people and ethnic groups are targeted with promotions. Industry representatives couldn't explain why menthol smokers tend to smoke fewer cigarettes, or why cancer rates are higher among African American smokers 70 percent of whom smoke menthol but smoke fewer cigarettes per day than non-menthol smokers.
"Internal studies do not indicate that menthol cigarettes are smoked any differently or more intensely than non menthol," according to Lorillard's William True. "These studies reinforce the overwhelming weight of epidemiology literature that menthol and non menthol convey similar risk of chronic disease."
Прочитано на http://www.npr.org/blogs/health/2010/07/16/128563062/menthol-the-mystery-ingredient-in-cigarettes

Зевота действительно заразна!

Интересное видео и комментарии на http://scienceblogs.com/thoughtfulanimal/2010/07/yawn_yawn_yawn_yawn_yawn_conta.php

03.06.2010

Новый способ флуоресцентного мечения белков

ScienceBlog.com

Может ли метамфетамин улучшить память?

Нет, скорее, он может ухудшить забывание, - пишут на http://www.eurekalert.org/pub_releases/2010-05/tcob-som052010.php
Snails on methamphetamine


How methamphetamine improves snail's memory

Crystal meth (methamphetamine) is a highly addictive drug that seduces victims by increasing self-esteem and sexual pleasure, and inducing euphoria. But once hooked, addicts find the habit hard to break. Barbara Sorg from Washington State University, USA, explains that amphetamines enhance memory. 'In addiction we talk about the "drug memory" as a "pathological memory". It is so potent as to not be easily forgotten,' she explains. As memory plays an important role in addiction, Sorg wondered whether it might be possible to find out more about the effects of meth on memory by looking at the effect it has on a humble mollusc: the pond snail Lymnaea stagnalis.
Lymnaea hold memories about when to breathe through their breathing tubes (pneumostomes) in a three neuron network, which is much simpler than the colossal circuits that hold our memories. Ken Lukowiak from University of Calgary, Canada, has been working on the mechanisms of memory formation in these snails for most of his career, so he and Sorg decided to team up to find out whether a dose of meth could improve the snails' memories in the way it does human memories. They publish their discovery that memories formed by snails under the influence of meth are harder to forget, which could help us to understand human addiction, on 28 May 2010 in The Journal of Experimental Biology at http://jeb.biologists.org/.
First Sorg and her students had to discover whether a dose of meth could affect the snails' breathing behaviour. According to Lukowiak, the snails breathe through their skins when oxygen levels are high, but when oxygen levels drop the snails extend their pneumostomes above the water's surface to supplement the supply. As the drug easily crosses the snail's skin, the team immersed the snails in de-oxygenated pond water spiked with meth, and watched to see how it affected their breathing. The snails stopped raising their pnemostomes at 1 and 3.3·μmol·l-1 meth, so having found a dose that altered the snail's behaviour, the team began testing its effects on the mollusc's long term memory.
The team trained the snails to remember to keep their pneumostomes closed when oxygen levels were low by poking them with a stick every time they tried to open their pneumostomes. Giving the snails two training sessions separated by an hour, the team knew that the molluscs would hold the memory for over 24·h, but what would happen if they trained the snails in meth-laced water?
Testing the snails in de-oxygenated pond water 24 hours later, the team were surprised to see that the snails seemed to have no recollection of their training, popping their pneumostomes above the water's surface. Maybe meth did not affect the snails' memories. But then Lukowiak remembered: 'If you put snails in a novel context even though they have memory they respond as if they don't have memory,' he says. Without meth in the water, the snails were ignoring their memory. However, when the team reintroduced meth to the test water, the snails suddenly remembered to keep their pneumostomes closed. This could explain why it's so hard for human addicts to kick the habit when returning to old haunts that trigger the addiction memory.

Next the team wondered whether meth could improve the snails' memories. First they immersed the snails in meth-laced pond water, then they moved them into regular de-oxygented pond water and gave them a training session that the snails should only recall for a few hours. In theory the snails should have forgotten their training 24 hours later, but would the meth improve the snails' memories so they remembered to keep their pneomostomes closed a day later? It did. A dose of meth prior to training had improved the snails' memories, allowing them to recall a lesson that they should have already forgotten. And when the team tested whether they could mask the meth memory with another memory, they found that the meth memory was much stronger and harder to mask.

So memories formed under the influence of meth seem to be harder to forget, possibly because the drug disrupts the mechanisms for forgetting, and could help us to understand how amphetamines enhance memory in humans.


###

IF REPORTING ON THIS STORY, PLEASE MENTION THE JOURNAL OF EXPERIMENTAL BIOLOGY AS THE SOURCE AND, IF REPORTING ONLINE, PLEASE CARRY A LINK TO: http://jeb.biologists.org/

REFERENCE: Kennedy, C. D., Houmes, S. W., Wyrick, K. L., Kammerzell, S. M., Lukowiak, K. and Sorg, B. A. (2010). Methamphetamine enhances memory of operantly conditioned respiratory behavior in the snail Lymnaea stagnalis. J. Exp. Biol. 213, 2055-2065.

This article is posted on this site to give advance access to other authorised media who may wish to report on this story. Full attribution is required, and if reporting online a link to jeb.biologists.com is also required. The story posted here is COPYRIGHTED. Therefore advance permission is required before any and every reproduction of each article in full. PLEASE CONTACT permissions@biologists.com

THIS ARTICLE APPEARS IN THE JOURNAL OF EXPERIMENTAL BIOLOGY ON: 28 May 2010. EMBARGOED UNTIL THURSDAY, 27 May 2010, 17:00 HRS EST

10.05.2010

Синестезия. Подборка хороших материалов

Классные статьи о синестезии:
http://scienceblogs.com/neurophilosophy/2010/05/different_types_of_synaesthetic_experiences_involve_different_brain_mechanisms.php?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+ScienceblogsChannelBrain+%28ScienceBlogs+Channel+%3A+Brain+%26+Behavior%29


http://feedproxy.google.com/~r/ScienceblogsCombinedFeed/~3/fPx_LX67wuc/feeling_the_pain_of_others.php

http://feeds.newscientist.com/c/749/f/10897/s/7e8ef3e/l/0L0Snewscientist0N0Cgallery0Cmg20A42739380A0A0Eis0Esynaesthesia0Ea0Ehighlevel0Ebrain0Epower0DDCMP0FOTC0Erss0Gnsref0Fonline0Enews/story01.htm

http://feeds.newscientist.com/c/749/f/10897/s/7e85050/l/0L0Snewscientist0N0Carticle0Cmg20A4273930B80A0A0Eis0Esynaesthesia0Ea0Ehighlevel0Ebrain0Epower0Bhtml0DDCMP0FOTC0Erss0Gnsref0Fonline0Enews/story01.htm

http://feedproxy.google.com/~r/ScienceblogsChannelBrain/~3/hyn8YtX-SdI/the_cognitive_benefits_of_time-space_synaesthesia.php


http://feeds.feedburner.com/~r/ScienceblogsCombinedFeed/~3/532993209/synaesthesia_the_neurological_condition_in.php

http://feeds.newscientist.com/c/749/f/10897/s/2fd6f01/l/0L0Snewscientist0N0Carticle0Cdn165370Egenetic0Eroots0Eof0Esynaesthesia0Eunearthed0Bhtml0DDCMP0FOTC0Erss0Gnsref0Fonline0Enews/story01.htm

http://www.eurekalert.org/pub_releases/2009-02/cp-sns012909.php


http://feeds.feedburner.com/~r/ScienceblogsCombinedFeed/~3/471476515/tactile_emotion_synaesthesia.php


http://www.scientificblogging.com/news_releases/synaesthesia_cognitive_cross_talk_and_using_hypnosis_induce_it

http://feeds.feedburner.com/~r/ScienceblogsChannelBrain/~3/356593224/the_sound_of_dots_moving_new_form_of_synaesthesia.php

http://www.scienceblog.com/cms/research-shows-consistency-synaesthetic-experiences-16166.html


http://www.scientificblogging.com/news_releases/synaesthesia_smelling_a_sound_or_hearing_a_color

http://feeds.biologynews.net/~r/biologynews/headlines/~3/206827700/1_person_out_of_every_1000_has_synaesthesia_in_which_an_individual_can_smell_a_sound.html

http://feeds.feedburner.com/~r/ScienceblogsCombinedFeed/~3/185949804/the_hidden_sense.php

http://feeds.feedburner.com/~r/ScienceblogsCombinedFeed/~3/175110107/a_journey_to_the_center_of_the.php


http://feeds.feedburner.com/~r/ScienceblogsCombinedFeed/~3/159447134/can_you_hear_this_painting.php


http://feeds.feedburner.com/~r/ScienceblogsCombinedFeed/~3/127133716/color_opponency_in_synaesthesi_1.php

http://feeds.feedburner.com/~r/ScienceblogsCombinedFeed/~3/122692989/synthetic_space_binding_errors.php
http://feeds.feedburner.com/~r/ScienceblogsCombinedFeed/~3/471476515/tactile_emotion_synaesthesia.php

The Clock Is Off: Bipolar Disorder and Circadian Rhythm | ScienceBlog.com

Эндометриальные стволовые клетки и допамин

Информация о возможных способах лечения болезни Паркинсона стволовыми клетками описан на http://www.eurekalert.org/pub_releases/2010-05/nioc-esc050610.php

Endometrial stem cells restore brain dopamine levels

Mouse study may lead to new therapies for Parkinson's Disease

Endometrial stem cells injected into the brains of mice with a laboratory-induced form of Parkinson's disease appeared to take over the functioning of brain cells eradicated by the disease.
The finding raises the possibility that women with Parkinson's disease could serve as their own stem cell donors. Similarly, because endometrial stem cells are readily available and easy to collect, banks of endometrial stem cells could be stored for men and women with Parkinson's disease.
"These early results are encouraging," said Alan E. Guttmacher, M.D., acting director of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), the NIH Institute that funded the study. "Endometrial stem cells are widely available, easy to access and appear to take on the characteristics of nervous system tissue readily."
Parkinson's disease results from a loss of brain cells that produce the chemical messenger dopamine, which aids the transmission of brain signals that coordinate movement.
This is the first time that researchers have successfully transplanted stem cells derived from the endometrium, or the lining of the uterus, into another kind of tissue (the brain) and shown that these cells can develop into cells with the properties of that tissue.
The findings appear online in the Journal of Cellular and Molecular Medicine.
The study's authors were Erin F. Wolff, Xiao-Bing Gao, Katherine V. Yao, Zane B. Andrews, Hongling Du, John D. Elsworth and Hugh S. Taylor, all of Yale University School of Medicine.
Stem cells retain the capacity to develop into a range of cell types with specific functions. They have been derived from umbilical cord blood, bone marrow, embryonic tissue, and from other tissues with an inherent capacity to develop into specialized cells. Because of their ability to divide into new cells and to develop into a variety of cell types, stem cells are considered promising for the treatment of many diseases in which the body's own cells are damaged or depleted.
In the current study, the researchers generated stem cells using endometrial tissue obtained from nine women who did not have Parkinson's disease and verified that, in laboratory cultures, the unspecialized endometrial stem cells could be transformed into dopamine-producing nerve cells like those in the brain.
The researchers also demonstrated that, when injected directly into the brains of mice with a Parkinson's-like condition, endometrial stem cells would develop into dopamine-producing cells.
Unspecialized stem cells from the endometrial tissue were injected into mouse striatum, a structure deep in the brain that plays a vital role in coordinating balance and movement. When the researchers examined the animals' striata five weeks later, they found that the stem cells had populated the striatum and an adjacent brain region, the substantia nigra. The substantia nigra produces abnormally low levels of dopamine in human Parkinson's disease and the mouse version of the disorder. The researchers confirmed that the stem cells that had migrated to the substantia nigra became dopamine-producing nerve cells and that the animals' dopamine levels were partially restored.
The study did not examine the longer-term effects of the stem cell transplants or evaluate any changes in the ability of the mice to move. The researchers noted that additional research would need to be conducted to evaluate the safety and efficacy of the technique before it could be approved for human use.
According to the researchers, stem cells derived from endometrial tissue appear to be less likely to be rejected than are stem cells from other sources. As expected, the stem cells generated dopamine producing cells when transplanted into the brains of mice with compromised immune systems. However, the transplants also successfully gave rise to dopamine producing cells in the brains of mice with normal immune systems.
According to Dr. Taylor, because women could provide their own donor tissue, there would be no concern that their bodies would reject the implants. Moreover, because endometrial tissue is widely available, banks of stem cells could be established. The stem cells could be matched by tissue type to male recipients with Parkinson's to minimize the chances of rejection.
In addition, Dr. Taylor added that endometrial stem cells might prove to be easier to obtain and easier to use than many other types of stem cells. With each menstrual cycle, women generate new endometrial tissue every month, so the stem cells are readily available. Even after menopause, women taking estrogen supplements are capable of generating new endometrial tissue. Because doctors can gather samples of the endometrial lining in a simple office procedure, it is also easier to collect than other types of adult stem cells, such as those from bone marrow, which must be collected surgically.
"Endometrial tissue is probably the most readily available, safest, most easily attainable source of stem cells that is currently available. We hope the cells we derived are the first of many types that will be used to treat a variety of diseases," said senior author Hugh S. Taylor, M.D., of Yale University. "I think this is just the tip of the iceberg for what we will be able to do with these cells."
###
The NICHD sponsors research on development, before and after birth; maternal, child, and family health; reproductive biology and population issues; and medical rehabilitation. For more information, visit the Institute's Web site at http://www.nichd.nih.gov/.
The National Institutes of Health (NIH) — The Nation's Medical Research Agency — includes 27 Institutes and Centers and is a component of the U. S. Department of Health and Human Services. It is the primary federal agency for conducting and supporting basic, clinical, and translational medical research, and it investigates the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit http://www.nih.gov.

05.05.2010

Солярий = наркотик?

Очень классное исследование показывает, что между посещением соляриев и склонностью к зависимостям, в том числе и наркотической, есть прямая связь. Материал с http://blisstree.com/feel/white-hot-addiction-skin-cancer-and-the-tanning-bed/:
Even though the 80s are long gone, tanning bed addiction is alive and well, a recent study suggests. Fake rays are like crack for some UV bed frequenters.
Researchers decided to examine a link from tanning to substance abuse and depression in college students, and found that among 229 of them, 90 qualified as “addicted to indoor tanning.” And those addicts reported greater symptoms of anxiety and more drug and alcohol use.
Heavy tanners actually missed going outside to catch the sun’s natural rays. More than 3/4 of the most frequent tanners tried to cut down on indoor tanning sessions, but had been unable to, according to The New York Times.
How can a person be addicted to a neon blue lit coffin? As with exercise, research suggests that UV rays may release endorphins. And even though everyone in the study knew the health risks involved with tanning, it seems that – for some people – achieving that golden goddess glow might be worth a little skin cancer.

Новые новости :)

Очень интересные материалы по связи сна и лишнего веса: http://www.scientificblogging.com/news_articles/teens_who_sleep_less_gain_more_weight_study_finds
О новом антикокаиновом препарате: http://www.scientificblogging.com/news_articles/coce_therapy_cocaine_toxicity
Хороший пост об эффективности антидепрессантов: http://blisstree.com/feel/mental-health-are-antidepressants-all-in-your-head/

16.04.2010

Сочувствие и жестокость связаны на уровне мозга

Интересные нововсти на http://www.biologynews.net/archives/2010/04/09/empathy_and_violence_have_similar_circuits_in_the_brain.html
"Just as our species could be considered the most violent, since we are capable of serial killings, genocide and other atrocities, we are also the most empathetic species, which would seem to be the other side of the coin", Luis Moya Albiol, lead author of the study and a researcher at the UV, tells SINC.


This study, published in the most recent issue of the Revista de Neurología, concludes that the prefrontal and temporal cortex, the amygdala and other features of the limbic system (such as insulin and the cingulated cortex) play "a fundamental role in all situations in which empathy appears".

Moya Albiol says these parts of the brain overlap "in a surprising way" with those that regulate aggression and violence. As a result, the scientific team argues that the cerebral circuits – for both empathy and violence – could be "partially similar".

"We all know that encouraging empathy has an inhibiting effect on violence, but this may not only be a social question but also a biological one – stimulation of these neuronal circuits in one direction reduces their activity in the other", the researcher adds.

This means it is difficult for a "more empathetic" brain to behave in a violent way, at least on a regular basis. "Educating people to be empathetic could be an education for peace, bringing about a reduction in conflict and belligerent acts", the researcher concludes.

Techniques for measuring the human brain "in vivo", such as functional magnetic resonance imaging, are making it possible to find out more about the structures of the brain that regulate behaviour and psychological processes such as empathy.

Source : FECYT - Spanish Foundation for Science and Technology

Новая система измерения параметров клеток

Читаю на http://www.biologynews.net/archives/2010/04/12/mit_new_cell_measurement_system.html
Using a sensor that weighs cells with unprecedented precision, MIT and Harvard researchers have measured the rate at which single cells accumulate mass — a feat that could shed light on how cells control their growth and why those controls fail in cancer cells.


The research team, led by Scott Manalis, MIT associate professor of biological engineering, revealed that individual cells vary greatly in their growth rates, and also found evidence that cells grow exponentially (meaning they grow faster as they become larger).

The new measurement system, reported in the April 11 edition of the journal Nature Methods, is the first technique that can measure cells' mass as they grow over a period of time, ranging from five to 30 minutes. Previous methods for measuring cell growth rates have focused on volume or length measurements, and have not yet exhibited the necessary precision for revealing single cell growth models.

How they did it: The cell-mass sensor, which Manalis first demonstrated in 2007, consists of a fluid-filled microchannel etched in a tiny silicon slab that vibrates inside a vacuum. As cells flow through the channel, one at a time, their mass slightly alters the slab's vibration frequency. The mass of the cell can be calculated from that change in frequency, with a resolution as low as a femtogram (10-15 grams).

Michel Godin, a former postdoctoral associate in Manalis' lab and co-lead author of the paper, developed a way to trap a cell within the microchannel by precisely coordinating the flow direction. That enables the researchers to repeatedly pass a single cell through the channel every second or so, measuring it each time it moves through.

The researchers studied four types of cells: two strains of bacteria (E. coli and B. subtilis), a strain of yeast and mammalian lymphoblasts (precursors to white blood cells). They showed that B. subtilis cells appear to grow exponentially, but they did not obtain conclusive evidence for E. coli. That's because there is so much variation between individual cell growth rates in E. coli, even for cells of similar mass, says Francisco Delgado, a grad student in Manalis' lab and co-lead author of the paper.

If cells do grow exponentially, it means there must be some kind of mechanism to control that growth. Otherwise, when cells divide into two slightly different-sized daughter cells, as they often do, the larger cell in each generation would always grow faster than the smaller cell, leading to inconsistent cell sizes.

"If there were no control over the process, the variation in cell size would be all over the map," says Marc Kirschner, professor of systems biology at Harvard Medical School and an author of the paper. However, biologists don't know yet how that control mechanism might work.

Next steps: In their current studies, the researchers are tagging proteins inside the cell with fluorescent molecules that reveal what stage of the cell cycle the cell is in, allowing them to correlate cell size with cell cycle position. They are also working on a way to add chemicals such as nutrients, antibiotics and cancer drugs to the fluid inside the microchannel, so they can study how those substances affect growth rates.

Source : Massachusetts Institute of Technology

24.03.2010

У двух психов вероятность родить третьего повышается

Мда... Читаем на http://www.eurekalert.org/pub_releases/2010-03/jaaj-oot022510.php:
Offspring of 2 psychiatric patients have increased risk of developing mental disorders


Offspring of two parents with schizophrenia or bipolar disorder appear more likely to develop the same illness or another psychiatric condition than those with only one parent with psychiatric illness, according to a report in the March issue of Archives of General Psychiatry, one of the JAMA/Archives journals.

The offspring of two parents with psychiatric illness represent an extremely high-risk group, according to background information in the article. Studying these children permits researchers to assess the risk associated with two sources of genetic predisposition to mental disorders. "Such risks will be of use to genetic counselors to inform personal decisions with regard to marriage, family formation, adoption and health insurance planning," the authors write.

Irving I. Gottesman, Ph.D., Hon.F.R.C.Psych., of the University of Minnesota Medical School, Minneapolis, and colleagues studied a population-based cohort of 2.7 million individuals born in Denmark. The researchers matched records in a general registry of the population with a database of psychiatric admissions. They identified individuals whose parents had both been admitted to psychiatric facilities for schizophrenia and bipolar disorder, and compared the rate of psychiatric admissions for these individuals to those of offspring with one or no parents admitted to psychiatric facilities.

Rates of schizophrenia were highest among offspring of two parents with schizophrenia. Of the 196 couples who both had schizophrenia, 27.3 percent of their 270 children were admitted to a psychiatric facility, increasing to 39.2 percent when schizophrenia-related disorders were included. This compared with a rate of 7 percent among 13,878 offspring of 8,006 couples in which one parent had schizophrenia and 0.86 percent in 2.2 million offspring of 1 million couples in which neither parent was admitted for schizophrenia.

Similarly, the risk of bipolar disorder was 24.9 percent in 146 offspring of 83 parent couples who were both admitted for bipolar disorder (increasing to 36 percent when unipolar depressive disorder was also included). This compared to a risk of 4.4 percent among 23,152 offspring of 11,995 couples with only one parent ever admitted for bipolar disorder and 0.48 percent in 2.2 million children of 1 million couples with neither parent ever admitted.

When one parent had bipolar disorder and the other had schizophrenia, offspring had a 15.6 percent risk of schizophrenia and an 11.7 percent risk of bipolar disorder.

The risks in this population "are of such a magnitude that they command clinical and national public health attention in countries with health care roughly similar to Denmark's," the authors write.

"It is important to keep in mind that the yields from genetic epidemiology and the strategies implemented are applicable to groups of people, not to the individuals themselves," they conclude. "However, by joining advances in molecular genetics that are adapted for use in epidemiological genetic screening, our kinds of data with the risk groups described might lead to a large and rapid step forward in the understanding of the etiologies of major mental disorders."

О вреде кокаина и метамфетамина

2 новых статьи:
http://www.eurekalert.org/pub_releases/2010-03/uoc--sdi031710.php - о том, что при повышенной температуре  воздуха, риск негативного влияния кокаина на организм увеличивается

http://www.eurekalert.org/pub_releases/2010-03/sfn-bai031210.php - о страшных последствиях употребления метамфетамина матерями.

"Заразительное" поведение в группах

Интересная работа, о которой я прочитала на http://www.eurekalert.org/pub_releases/2010-03/uoc--sdi031710.php
Sleep deprivation influences drug use in teens' social networks


More than 1 behavior can spread simultaneously across a social network

Recent studies have shown that behaviors such as happiness, obesity, smoking and altruism are "contagious" within adult social networks. In other words, your behavior not only influences your friends, but also their friends and so on. Researchers at the University of California, San Diego and Harvard University have taken this a step farther and found that the spread of one behavior in social networks – in this case, poor sleep patterns – influences the spread of another behavior, adolescent drug use.

The study, led by Sara C. Mednick, PhD, assistant professor of psychiatry at the University of California, San Diego School of Medicine and the VA San Diego Healthcare System, will be published March 19 in PLoS One.

"This is our first investigation of the spread of illegal drug use in social networks," said Mednick. "We believe it is also the first study in any age population on the spread of sleep behaviors through social networks."

Using social network data from the National Longitudinal Study of Adolescent Health, Mednick and her colleagues James H. Fowler, UCSD Department of Political Science and Nicholas A. Christakis, Harvard Medical School, mapped the social networks of 8,349 adolescents in grades 7 through 12. They found clusters of poor sleep behavior and marijuana use that extended up to four degrees of separation (to one's friends' friends' friends' friends) in the social network.

Another novel network effect that they discovered was that teens who are at the center of the network are at greater risk of poor sleep, which in turn means they are more likely to use marijuana – putting them at the crossroads of two behaviors increases a teenager's vulnerability.

Contrary to the general assumption that drug use has a negative effect on sleep, the researchers also found that sleep loss is likely to drive adolescents to use drugs – the less they sleep the more likely their friends are to sleep poorly and use marijuana.

"Our behaviors are connected to each other and we need to start thinking about how one behavior affects our lives on many levels," said Mednick. "Therefore, when parents, schools and law enforcement want to look for ways to influence one outcome, such as drug use, our research suggests that targeting another behavior, like sleep, may have a positive influence. They should be promoting healthy sleep habits that eliminate behaviors which interfere with sleep: take the TV out of the child's bedroom, limit computer and phone usage to daytime and early evening hours, and promote napping."

25.02.2010

О хронических "мигренозниках"

Статья о страдающих хроническими и спорадическими мигренями, на http://www.eurekalert.org/pub_releases/2010-02/bmj-cms021610.php

Chronic migraineurs sicker, poorer and more depressed than episodic migraineurs


Sociodemographic and comorbidity profiles of chronic migraine and episodic migraine sufferers

Chronic migraine sufferers tend to be in poorer general health, less well off, and more depressed than those with episodic migraine, reveals research published ahead of print in the Journal of Neurology Neurosurgery and Psychiatry.

The findings are based on almost 12,000 adults with episodic - a severe headache on up to 14 days of the month - or chronic migraine - headache on 15 or more days of the month.

All participants were already part of the American Migraine Prevalence and Prevention (AMPP) study, a long term US population based study of 24,000 headache sufferers, which has included regular surveys since 2004.

The research team analysed data collected in the 2005 survey on socioeconomic circumstances and other health problems.

The results showed that those with chronic migraine had significantly lower levels of household income, were less likely to be working full time, and were almost twice as likely to have a job related disability than their peers with episodic migraine.

They were twice as likely to be depressed, anxious, and experiencing chronic pain. And they were significantly more likely to have other serious health problems.

These included asthma, bronchitis, and chronic obstructive pulmonary disease (COPD), high blood pressure, diabetes, high cholesterol and obesity. They were also around 40% more likely to have heart disease and angina and 70% more likely to have had a stroke.

The authors point out that chronic migraine "can be an especially disabling and burdensome condition."

Previous research indicates that chronic migraineurs have a relatively high level of sick leave, reduced productivity, and poorer quality of family life than episodic migraineurs.

It also suggests that few are diagnosed correctly and that only around one in three are treated appropriately.

The differences unearthed between the two groups in the present study might reflect differences in biological risk factors and provide valuable clues as to how episodic migraine progresses to chronic migraine, suggest the authors

Три новых статьи об эффектах наркотических веществ

http://scienceblogs.com/drugmonkey/2010/02/synthetic_marijuana_k2_spice_j.php - о синтетической марихуане
http://www.scientificblogging.com/news_articles/does_recreational_drug_use_damage_memory - о проблемах с памятью у употребляющих психотропные вещества
http://scienceblogs.com/drugmonkey/2010/02/as_many_dependent_on_cannabis.php - о связи курения марихуаны и употребления героина

Отличный пост о повреждениях ДНК и стволовых клетках

Две мои любимейшие темы в одном чудесном посте. Автор - Ed Yong
All of our cells are staffed by armies of executioners. They are usually restrained but when unleashed, they can set off a fatal chain reaction that kills the cell. This suicide squad does away with billions of cells every day. It helps to balance the production of new cells with the loss of old ones, to sculpt growing tissues and to destroy potential cancer cells.


But a new study suggests that the executioners aren't always lethal. In fact, they're essential for life. Through the unorthodox method of damaging our DNA, they can actually activate important genes. This technique for switching genes on is new to science but it's apparently vital for allowing some types of stem cell to produce new types of tissue.
Stem cells are bundles of untapped potential, with the ability to produce hundreds of specialist cells across the body. This process is called differentiation. Its details vary depending on which type of cell is being produced, but scientists have recently found that some aspects are apparently common to all tissues, be they muscle, blood or bone. Surprisingly, one of these is the recruitment of executioner proteins - caspases.
Caspases cut up other proteins and in doing so, some of them produce yet more caspases. The result is a growing army of death, hacking and slashing its way through the cell. But one of these killers - caspase-3 - is a necessary part of differentiation. Get rid of it and, suddenly, stem cells can't produce their specialised daughters. Now, thanks to Brian Larsen from the Sprott Centre for Stem Cell Research, we know why.
Caspase-3 activates a protein called CAD (or caspase-activated DNase in full) by slicing apart other proteins holding it at bay. Once released, CAD lives up to its villainous acronym. It pairs up with an identical twin to create a molecule that looks and acts like a pair of scissors. The pair can cut DNA, cleaving the famous double helix in two. These sorts of cuts are normally very bad news for a cell. If they aren't repaired quickly and accurately, the consequences can include death or cancer.
But Larsen has found that stem cells deliberately break their own DNA by recruiting caspase-3 and CAD. This act of self-harm switches on important genes that are needed for differentiation; without it, the generalist cells can't specialise. This is an entirely new way of activating genes and it appears to be both important and widespread.
Larsen studied stem-like cells called myoblasts, which give rise to various types of muscle cells. As the myoblasts differentiated, Larsen watched for signs of shattered DNA using a clever test called the 'comet assay'. The technique involves puncturing a cell and placing it in an electric field. The field drives DNA through the punctured cell but only if it has already been broken into small pieces. If it has, it appears as a streak outside the cell, rather like the tail of a comet.
Sure enough, the comet test revealed that differentiating cells suffer from significant amounts of damaged DNA. Thankfully, the injuries are only temporary and the cells soon marshal their repairmen to fix the breaks.
The myoblasts need these breaks to produce muscle fibres and to create the breaks, they rely on caspase-3 and its ability to activate CAD. Larsen managed to block the development of muscle fibres by dousing myoblasts with chemicals that neutralise caspase-3. The same thing happened if he used cells with mutant versions of CAD, which couldn't be activated. In both cases, the cells failed to show any signs of broken DNA.
CAD targets a gene called p21 that's absolutely necessary for the development of muscle and plenty of other tissues. Larsen found that CAD cuts p21's 'promoter', a stretch of DNA lying next to the gene that's responsible for switching it on. Somehow, these cuts activate the gene. It's still not clear how this works, but Larsen has some ideas. The cuts could change how the surrounding DNA is packaged, exposing the p21 gene and making it easier to 'read'. Alternatively, the cuts could remove chemical 'marks' attached to the DNA that would otherwise silence it.
Damaging your own DNA may seem like a rather extreme tactic for a cell to take but it's not unheard of as a deliberate ploy. Whenever we face new infections, our body generates antibodies by breaking the DNA of special genes, stitching them back together in new combinations. That's a very controlled process, but so is the damage that leads to differentiation. It's a careful surgical strike, rather than a shock and awe campaign.
During differentiation, Larsen found that DNA breaks are actually few and far between. They appear to be carefully orchestrated so that the entire genome doesn't become a shattered mess. This precision is even more remarkable when you consider that CAD cuts DNA indiscriminately, with little care for specific sequences. Larsen thinks that CAD is constrained by the way the DNA is packaged, so that only places that are meant to be cut are exposed for slicing and dicing. Only further experiments will tell if he is right.

Reference: Larsen et al. 2010. Caspase 3/caspase-activated DNase promote cell differentiation by inducing DNA strand breaks. http://dx.doi.org/10.1073/pnas.0913089107

Статья с http://scienceblogs.com/notrocketscience/2010/02/our_cells_produce_new_tissues_by_recruiting_executioners_to.php

06.02.2010

Суицидальная нетрадиционность...

Оказывается, самоидентификация геев, лесбиянок и бисексуалов увеличивает риск суицида. Читаем на http://www.eurekalert.org/pub_releases/2010-02/jgh-yws020510.php
Mental health professionals have long-known that gay, lesbian and bisexual (GLB) teens face significantly elevated risks of mental health problems, including suicidal thoughts and suicidal attempts. However, a group of McGill University researchers in Montreal has now come to the conclusion that self-identity is the crucial risk-factor, rather than actual sexual behaviours. Their results were published in February in the Journal of the American Academy of Child & Adolescent Psychiatry.
The researchers administered a detailed, anonymous questionnaire to nearly 1,900 students in 14 Montreal-area high schools, and found that those teens who self-identified as gay, lesbian or bisexual, or who were unsure of their sexual identity, were indeed at higher risk for suicidal ideation and attempts. However, teens who had same-sex attractions or sexual experiences – but thought of themselves as heterosexual – were at no greater risk than the population at large. Perhaps surprisingly, but consistent with previous studies, the majority of teens with same-sex sexual attraction or experience considered themselves to be heterosexual.
"This is the first study that has separated sexual identity from sexual attractions and behaviours in looking at risk for poor mental health outcomes," said corresponding author Dr. Brett Thombs, of the Lady Davis Institute for Medical Research (LDI) at the Jewish General Hospital.
"It's important to realize that a large proportion of people who have sex with or are attracted to people of the same sex do not identify themselves as gay, lesbian or bisexual. They consider themselves heterosexual." added co-author Dr. Richard Montoro of the McGill University Health Centre (MUHC). "Those students were not at all at risk of worse mental health outcomes."
"The main message is that it's the interface between individuals and society that causes students who identify as gay, lesbian, or bisexual the most distress," said study first author Yue Zhao, a McGill University graduate student working with Dr. Thombs.. "Sexual orientation has three different components. The first is identity, which is dependent on the society in which one lives; the second is attraction or fantasy; and the third is behaviour. Previous studies have not addressed which of those components may explain why GLB youth are at risk."
"What this all means is that clinicians need to look not just at individuals and their sexuality, they really need to assess the environment they are coming from and how they see themselves within it," said study co-author Dr. Karine Igartua. Igartua and Montoro are co-directors of the McGill University Sexual Identity Centre (MUSIC), the first gay and lesbian mental health centre in Canada.
"Our findings also clearly suggest that further study of the link between anti-gay sentiment and suicidality need to be undertaken," added Thombs.

02.02.2010

Новости о ферментах репарации ДНК

Читаем на http://www.biologynews.net/archives/2010/01/28/researchers_find_new_way_to_study_how_enzymes_repair_dna_damage.html
Researchers at Ohio State University have found a new way to study how enzymes move as they repair DNA sun damage -- and that discovery could one day lead to new therapies for healing sunburned skin.
Ultraviolet (UV) light damages skin by causing chemical bonds to form in the wrong places along the DNA molecules in our cells. Normally, other, even smaller molecules called photolyases heal the damage. Sunburn happens when the DNA is too damaged to repair, and cells die.
Photolyases have always been hard to study, in part because they work in tiny fractions of a second. In this week's online edition of the Proceedings of the National Academy of Sciences, Ohio State physicist and chemist Dongping Zhong and his colleagues describe how they used ultra-fast pulses of laser light to spy on a photolyase while it was healing a strand of DNA.
This is the first time that anyone has observed this enzyme motion without first attaching a fluorescent molecule to the photolyase, which disturbs its movements. They were able to see the enzyme's motion to help the healing process as it happens in nature.
"Now that we have accurately mapped the motions of a photolyase at the site of DNA repair, we can much better understand DNA repair at the atomic scale, and we can reveal the entire repair process with unprecedented detail," said Zhong, the Robert Smith Associate Professor of Physics, and associate professor in the departments of chemistry and biochemistry at Ohio State.
Such small motions are very hard to study. Typically, researchers deal with the problem by attaching tiny bits of fluorescent molecules to the enzymes they are trying to study. But adding an extra molecule to an enzyme such as photolyase could change how it moves.
"Once you tag it, you can't be sure that the motions you detect are the true motions of the molecule as it would normally function," Zhong explained.
So instead of using tags, he and his team took laser "snapshots" of a single photolyase in action in the laboratory. They mapped the shape and position of the photolyase molecule as it broke up the harmful chemical bonds in DNA caused by UV light. The whole reaction lasted only a few billionths of a second.
In nature, DNA avoids damage by converting UV rays into heat. Sunscreen lotions protect us by reflecting sunlight away from the skin, and also by dissipating UV as heat.
Sunburn happens when the DNA absorbs the UV energy instead of converting it to heat. This is due in part to the random position of the DNA molecule within our cells when the UV hits it. When the UV energy is absorbed, it triggers chemical reactions that form lesions -- errant chemical bonds -- along the DNA strand.
If photolyases are unable to completely repair the lesions, the DNA can't replicate properly. Badly damaged cells simply die — that's what gives sunburn its sting. Scientists also believe that chronic sun damage creates mutations that lead to diseases such as skin cancer.
The work in Zhong's lab is fundamental to the understanding of how those molecules interact. Other researchers could use this information to design drugs to heal sun damage.
"Of course, the ultimate goal of studying DNA repair is to help design artificial systems to mimic it," he said.

Source : Ohio State University

25.01.2010

О некоторых особенностях амбидекстров

Интересные новости на http://www.scienceblog.com/cms/mixed-handed-children-more-likely-have-mental-health-language-and-scholastic-problems.html. Вообще-то странно. Мне всегда казалось, что люди с в равной степени развитыми полушариями мозга, должны быть более успешны... А оказывается, не всегда:
Children who are mixed-handed, or ambidextrous, are more likely to have mental health, language and scholastic problems in childhood than right- or left-handed children, according to a new study published today in the journal Pediatrics.
The researchers behind the study, from Imperial College London and other European institutions, suggest that their findings may help teachers and health professionals to identify children who are particularly at risk of developing certain problems.
Around one in every 100 people is mixed-handed. The study looked at nearly 8,000 children, 87 of whom were mixed-handed, and found that mixed-handed 7 and 8-year old children were twice as likely as their right-handed peers to have difficulties with language and to perform poorly in school.
When they reached 15 or 16, mixed-handed adolescents were also at twice the risk of having symptoms of attention deficit/hyperactivity disorder (ADHD). They were also likely to have more severe symptoms of ADHD than their right-handed counterparts. It is estimated that ADHD affects between 3 to 9 percent of school-aged children and young people.
The adolescents also reported having greater difficulties with language than those who were left- or right-handed. This is in line with earlier studies that have linked mixed-handedness with dyslexia.
Little is known about what makes people mixed-handed but it is known that handedness is linked to the hemispheres in the brain. Previous research has shown that where a person's natural preference is for using their right hand, the left hemisphere of their brain is more dominant.
Some researchers have suggested that mixed-handedness indicates that the pattern of dominance is not that which is typically seen in most people, i.e. it is less clear that one hemisphere is dominant over the other. One study has suggested that ADHD is linked to having a weaker function in the right hemisphere of the brain, which could help explain why some of the mixed-handed students in today's study had symptoms of ADHD.
Dr Alina Rodriguez, the lead researcher on the study from the School of Public Health at Imperial College London, said: "Mixed-handedness is intriguing -- we don't know why some people prefer to make use of both hands when most people use only one. Our study is interesting because it suggests that some children who are mixed handed experience greater difficulties in school than their left- and right-handed friends. We think that there are differences in the brain that might explain these difficulties, but there needs to be more research.
"Because mixed-handedness is such a rare condition, the number of mixed-handed children we were able to study was relatively small, but our results are statistically and clinically significant. That said, our results should not be taken to mean that all children who are mixed-handed will have problems at school or develop ADHD. We found that mixed-handed children and adolescents were at a higher risk of having certain problems, but we'd like to stress that most of the mixed-handed children we followed didn't have any of these difficulties," added Dr Rodriguez.
To study the effects of mixed-handedness, Dr Rodriguez and her colleagues looked at prospective data from a cohort of 7,871 children from Northern Finland. Using questionnaires, the researchers assessed the children when they reached 7 to 8 years of age and again at 15 to 16 years of age.
When the children were aged 8, the researchers asked parents and teachers to assess their linguistic abilities, scholastic performance and behaviour. The teachers reported whether children had difficulties in reading, writing or mathematics and rated the children's academic performance as below average, average or above average.
The adolescents' parents and the adolescents themselves completed follow-up questionnaires when they were 15-16 years of age, with the children evaluating their school performance in relation to their peers and the parents assessing their children's behaviour, on a questionnaire that is widely used to identify ADHD symptoms.
The research was funded by the Academy of Finland; Sigrid Juselius Foundation, Finland; Thule Institute, University of Oulu, Finland; and the National Institute of Mental Health. Dr Rodriguez received support from VINNMER.

22.01.2010

Роль поврежлений ДНК в атаксии Фридриха

Очередные открытия связанные с изучением моих любимейших повреждений ДНК описаны на http://www.scienceblog.com/cms/excess-dna-damage-found-cells-patients-friedreichs-ataxia-29177.htm:
PITTSBURGH, Jan. 14 -- Elevated levels of DNA damage have for the first time been found in the cellular mitochondria and nuclei of patients with the inherited, progressive nervous system disease called Friedreich's ataxia (FRDA), says a multicenter research team led by an expert from the University of Pittsburgh Cancer Institute (UPCI). The findings, described today in PLoS Genetics, shed light on the molecular abnormalities that lead to the disease, as well as point the way to new therapeutic approaches and the development of biomarker blood tests to track its progression.
"In FRDA, mutations in the gene frataxin reduce production of a protein that plays a role in keeping iron levels in balance within mitochondria," explained Bennett Van Houten, Ph.D., Richard M. Cyert Professor of Molecular Oncology and leader of the molecular and cellular cancer biology program at UPCI, and professor, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine. "Frataxin binds iron and helps build iron-sulfur clusters, which are important constituents of cellular proteins.
"While iron is what allows blood cells to carry oxygen, too much iron is toxic to the body," said Astrid C. Haugen, lead author and program analyst at the National Institute of Environmental Health Sciences (NIEHS), part of the National Institutes of Health (NIH). "Friedreich's ataxia leads to iron overload, setting the stage for cumulative DNA damage that eventually affects patients' nerve and muscle cells."
According to the National Institute of Neurological Disorders and Stroke (NINDS), about 1 out of 50,000 Americans has Friedreich's ataxia. Symptoms appear from 5 to 15 years of age and include ataxia, or gait disturbance, that results from degeneration of nerves in the spinal cord and muscle; muscle wasting; and speech problems. Heart enlargement, arrhythmias, and heart failure are common and often the cause of early death in the most severely affected. Patients typically require wheelchairs within 10 to 20 years after symptoms begin.
For the study, the researchers profiled gene activity in blood samples from FRDA children to search for biomarkers of the disease, as compared to young healthy donors. Those data were compared to blood tests from FRDA adults, and the latter compared to a second group of healthy individuals.
"We saw gene activity patterns that are associated with responses to DNA damage, and our comparisons and follow-up tests showed us that FRDA patients have far more damage than seen in healthy people," said Dr. Van Houten, who noted that everyone has some DNA damage, at various stages of repair, in their cells. "We found gene expression signatures that correlated with frataxin levels, age of disease onset and a standardized measure of patient disability."
"If further testing validates the set of genes and activity profiles as predictive biomarkers, they could be useful in assessing the current status of a patient's illness as well as the response to experimental therapies in clinical trials," he said. "Also, new drug targets might be found in the DNA repair and iron-processing pathways affected by the lack of frataxin, generating much-needed treatment breakthroughs."
The study team includes researchers from NIEHS; NINDS; Durham, N.C.-based Expression Analysis Inc.; Duke University; Université Pierre et Marie Curie, Paris; and Hôpital Pitié-Salpêtrière, Paris.
This work was supported by the NIH Intramural Program and a Bench-to-Bedside award.
About UPCI
As the only NCI-designated comprehensive cancer center in western Pennsylvania, UPCI is a recognized leader in providing innovative cancer prevention, detection, diagnosis, and treatment; bio-medical research; compassionate patient care and support; and community-based outreach services. UPCI investigators are world-renowned for their work in clinical and basic cancer research.
About the University of Pittsburgh School of Medicine
As one of the nation's leading academic centers for biomedical research, the University of Pittsburgh School of Medicine integrates advanced technology with basic science across a broad range of disciplines in a continuous quest to harness the power of new knowledge and improve the human condition. Its Department of Pharmacology & Chemical Biology fosters an intellectual and physical environment in which basic chemical principles are applied to the understanding of cell signaling events with the goal of creating new therapeutic strategies. Driven mainly by the School of Medicine and its affiliates, Pitt has ranked among the top 10 recipients of funding from the National Institutes of Health since 1997 and now ranks fifth in the nation, according to preliminary data for fiscal year 2008. Likewise, the School of Medicine is equally committed to advancing the quality and strength of its medical and graduate education programs, for which it is recognized as an innovative leader, and to training highly skilled, compassionate clinicians and creative scientists well-equipped to engage in world-class research. The School of Medicine is the academic partner of UPMC, which has collaborated with the University to raise the standard of medical excellence in Pittsburgh and to position health care as a driving force behind the region's economy. For more information about the School of Medicine, see www.medschool.pitt.edu.

Link:

http://www.upmc.com/communications/newsbureau

Средство борьбы с кокаином!

Интересные новости. Новый способ борьбы с кокаиновой зависимостью описан на http://www.eurekalert.org/pub_releases/2010-01/fo1b-ana122309.php:
A new ally in the battle against cocaine addiction


A recent study shows that a bacterial protein may help cocaine addicts break the habit.
Cocaine esterase (CocE) is a naturally-occurring bacterial enzyme that breaks down cocaine, thereby reducing its addictive properties. The efficacy of CocE in animals and its suitability for treatment of addiction has been limited by its short half-life in the body.

A recent study, published in the Journal of Pharmacology and Experimental Therapeutics and reviewed by Faculty of 1000 Medicine's Friedbert Weiss, demonstrates that a more stable version of CocE, double mutant or DM CocE, significantly decreased the desire for cocaine and prevented death from cocaine overdose.
In the study, rats were trained to self-administer cocaine by pressing a button in their cage, mimicking the need for regular doses of the drug during addiction. Rats treated with the double mutant form of CocE pressed the button to receive cocaine less often, suggesting that DM-CocE broke down the drug and dampened addiction.

DM-CocE decreased the rats' urge for cocaine but not for an addictive analogue, highlighting the degree of specificity for cocaine. Weiss notes that the DM-CocE enzyme also provides "long-lasting protection" against the toxic effects of a potentially lethal dose.

Though the effects of CocE can be overcome by a sufficiently large dose of cocaine, the present findings suggest that CocE has great promise as a drug abuse treatment.
Weiss says, "These therapeutic approaches may therefore not be "fail-safe" for reducing cocaine intake by determined users" but "long-acting forms of CocE represent potentially valuable treatment approaches not only for the prevention of cocaine-induced toxicity but also for ongoing cocaine abuse in humans."

10.01.2010

Две чудесных статьи о привыкании к кофеину

Ещё о дозировании витаминов

Интересная статья на http://www.scienceblog.com/cms/putting-limits-vitamin-e-28815.html:
Vitamin-fortified foods and dietary health supplements can ease health worries. But what kinds of vitamins are right for you? And how much of them should you take, and how often?
A research group from Tel Aviv University has done the most comprehensive and accurate study of clinical data on Vitamin E use and heart disease to date, and it warns that indiscriminate use of high-dose Vitamin E supplementation does more harm than good. Their results were recently reported in ATVB, a leading journal of cardiology, and discussed in the journal BioFactors.
"There were so many conflicting reports about Vitamin E and its effect on various diseases, particularly heart disease, that we wanted to set the record straight," says Prof. Dov Lichtenberg of TAU's Sackler School of Medicine.
"Our new study shows that some people may be harmed by the treatment, whereas others may benefit from it. Now we're trying to identify groups of people that are most likely to benefit from the effects of Vitamin E," adds study co-researcher Dr. Ilya Pinchuk. The TAU research team also included decision analyst Dr. Moshe Leshno of the Sackler Faculty of Medicine and the Leon Recanati Faculty of Management and Dr. Yedidya (Didi) Dotan, whose PhD thesis is the basis for this analysis.
A longer life without it?
Applying a very different approach than any previous study, the team of researchers put their heads together to draw definitive conclusions about Vitamin E. In their publication in ATVB the Tel Aviv University researchers evaluated the results of the prominent studies measuring the health benefits of Vitamin E but reached varying conclusions. There have been many previous publications on the subject. Analysis of the results of all these past publications together revealed that subjects who did not take a Vitamin E supplement enjoyed more quality-adjusted-life-years (QALY), a standard parameter used in medicine to assess the effect of medical interventions.
"To explain the meaning of this parameter," says Dr. Pinchuk, "consider a participant who was healthy during the first 10 out of 20 years of the study, but then suffered a stroke and became dependent on others throughout the following 10 years. The QALY during the first 10 years of healthy life is 10, but after the stroke the quality of life is only half of what this person had before. Therefore, the second decade is considered the equivalent of merely 5 years of healthy life and in sum a person's QALY is 15.
The researchers examined data from more than 300,000 subjects in the US, Europe and Israel. "Our major finding," says Dr. Pinchuk, "was that the average quality-adjusted life years (QALY) of Vitamin E- supplemented individuals was 0.30 less than that of untreated people. This, of course, does not mean that everybody consuming Vitamin E shortens their life by almost 4 months. But on average, the quality-adjusted longevity is lower for vitamin-treated people. This says something significant."
Overturning earlier studies
In the BioFactors article, the TAU researchers defined "the real challenge as being able to identify who is likely to benefit taking Vitamin E." They also explored the first hypothesis of the oxidative theory of atherosclerosis published more than 20 years ago, which was the basis for the widespread use of antioxidants today. At first, this hypothesis raised great enthusiasm that anti-oxidants like Vitamins E and C and flavonoids could be used to prevent disease or its progression. In this respect, the new findings are very disappointing.
"We've now concluded that going to the grocery or to a health food store to buy Vitamin E supplements, for the most part, won't do you good. In some cases it can do harm," says Dr. Pinchuk. "A doctor wouldn't prescribe anti-hypertension drugs to the whole population, only to those with low blood pressure. It seems this is true for antioxidants, too. When you give them to everybody, you may be doing more harm than good. Some people may benefit from it, but more may be harmed."
The researchers are now building sets of criteria that detail under what conditions Vitamin E supplements should be taken. They are also investigating the chemical mechanisms of antioxidants in general to better understand how they work.
American Friends of Tel Aviv University (www.aftau.org) supports Israel's leading and most comprehensive center of higher learning. In independent rankings, TAU's innovations and discoveries are cited more often by the global scientific community than all but 20 other universities worldwide.
Internationally recognized for the scope and groundbreaking nature of its research programs, Tel Aviv University consistently produces work with profound implications for the future.

Ещё один метод исследования активности мозга

МИТовцы, как обычно, доисследовались до интересных штук. Читаем на http://www.biologynews.net/archives/2010/01/06/mit_neuroengineers_silence_brain_cells_with_multiple_colors_of_light.html
Neuroscientists at MIT have developed a powerful new class of tools to reversibly shut down brain activity using different colors of light. When targeted to specific neurons, these tools could potentially lead to new treatments for the abnormal brain activity associated with disorders such as chronic pain, epilepsy, brain injury, and Parkinson's disease.

The tools work on the principle that such disorders might be best treated by silencing, rather than stimulating, brain activity. These "super silencers" exert exquisite control over the timing of the shutdown of overactive neural circuits – an effect that's impossible with existing drugs or other conventional therapies.

"Silencing different sets of neurons with different colors of light allows us to understand how they work together to implement brain functions," explains Ed Boyden, senior author of the study, to be published in the Jan. 7 issue of Nature. "Using these new tools, we can look at two neural pathways and study how they compute together. These tools will help us understand how to control neural circuits, leading to new understandings and treatments for brain disorders – some of the biggest unmet medical needs in the world." Boyden is the Benesse Career Development Professor in the MIT Media Lab and an associate member of the McGovern Institute for Brain Research at MIT.

Boyden's super silencers are developed from two genes found in different natural organisms such as bacteria and fungi. These genes, called Arch and Mac, encode for light-activated proteins that help the organisms make energy. When neurons are engineered to express Arch and Mac, researchers can inhibit their activity by shining light on them. Light activates the proteins, which lowers the voltage in the neurons and safely and effectively prevents them from firing. In this way, light can bathe the entire brain and selectively affect only those neurons sensitized to specific colors of light. Neurons engineered to express Arch are specifically silenced by yellow light, while those expressing Mac are silenced by blue light.

"In this way the brain can be programmed with different colors of light to identify and possibly correct the corrupted neural computations that lead to disease," explains co-author Brian Chow, postdoctoral associate in Boyden's lab.

In 2005, Boyden, in collaboration with investigators at Stanford University and the Max Planck Institute, introduced the first such "optogenetic" technique, so called because it combines the use of optics with gene delivery. The 2005 tool, now widely used, involves a light-activated ion channel, ChR2, which allows light to selectively turn on neurons in the brain.

Two years later, Boyden demonstrated that halorhodopsin, another light-sensitive protein, could inhibit the activity of neurons when illuminated. "But the genomic diversity of the world suggested that more powerful tools were out there waiting to be discovered," Boyden says. His group accordingly screened a diverse set of microbial light-sensitive proteins, and found the new multicolor silencers. The newly discovered tools are much better than the old. Arch-expressing neurons were switched off with greater precision and recovered faster than halorhodopsin-expressing neurons, allowing researchers to manipulate different neurons with different colors of light.

"Multicolor silencing dramatically increases the complexity with which you can study neural circuits," says co-author Xue Han, postdoctoral researcher in Boyden's lab. "We will use these tools to parse out the neural mechanisms of cognition."

How they did it: MIT researchers loaded the Arch and Mac genes into viruses that inserted their genetic cargo into mouse neurons. Optical fibers attached to lasers flashed light onto the neurons, and electrodes measured the resulting neural activity. [See graphic]

Next steps: Boyden's team recently demonstrated the efficacy of ChR2 in monkeys with no apparent side effects. Determining whether Arch and Mac are safe and effective in monkeys will be a critical next step toward the potential use of these optical silencing tools in humans. Boyden plans to use these super silencers to examine the neural circuits of cognition and emotion and to find targets in the brain that, when shut down, could relieve pain and treat epilepsy. His group continues to mine the natural world for new and even more powerful tools to manipulate brain cell activity – tools that, he hopes, will empower scientists to explore neural circuits in ways never before possible.

Source : Massachusetts Institute of Technology