Как правильно тестировать лекарства?

О правилах качественных клинических испытаний:

Ограничение калорий - работает ли для всех видов?

Много сейчас говорят о таком интересном способе продления жизни как снижение потребляемых калорий. Показано множество успешных результатов на грызунах. Всё очень аргументировано и элегантно. Однако совсем недавно в сети появились сообщения о подобных опытах, проведённых на приматах. И там результаты оказались не столь однозначными. 

Вот одно из таких сообщений:

Calorie Restriction May Make Rats Live Longer, But Doesn’t Work For Primates
Remember those famous studies in worms, mice and rats that indicated that a restricted-calorie diet increased lifespan? Well, the results of a 30-year study in rhesus monkeys has just been reported, and the results make it pretty clear that it doesn’t apply to primates … likely including us.
The molecular pathways and gene circuits that are activated in our bodies as a result of long-term calorie restriction are immensely complicated. Like a tangled ball of yarn complicated. We don’t understand how they work, frankly, and there’s just no magic bullet when it comes to diet and lifespan in creatures like monkeys and humans (I’m looking at you, resveratrol). It’s certainly good for one’s long-term survival not to overeat into Honey-Boo-Boobesity, but what does current science say about calories, long life and naked apes?
Studies of humans who live past 100 point to genetics as more important than restricting calories. Which genes? Time may tell. And none of this has helped us understand how different diet compositions may affect aging.
Read more at Nature News.

Спасибо за наводку jtotheizzoe.

Дрозофилье объявление о знакомстве

Немножко научного бугагизма.
Объявление, которое могла бы написать в мушиную газетёнку одинокая Дрозофилка:

Спасибо http://www.bios.niu.edu/bios308/funnies.htm

Допамин в свежих научных новостях

Я очень люблю допамин. Да и как можно его не любить, если именно это чудесное вещество отвечает за нашу мотивацию, удовольствие и другие приятности? В этом блоге достаточно много постов посвящены этому нейромедиатору, поэтому сейчас я хочу поделиться ссылкой на свежайшую статью из авторитетного источника, в которой раскрываются какие-то интересные и не известные до этого, сведения о допамине.

Сообщение на http://www.eurekalert.org/pub_releases/2011-12/osum-ans120111.php гласит, что допамин может быть крайне полезен при лечении опухолей. Оказывается, этот катехоламин способен увеличить эффективность действия противораковых препаратов и радиотерапии! Допамин улучшает приток крови к опухолям и таким образом повышает концентрацию действующих веществ именно в месте потребности, так же увеличивается уровень насыщения этих участков кислородом, что так же способствует борьбе с опухолью. Такие результаты были получены на животных моделях рака груди и кишечника.

Паразит мозг не съест, но химию его изменит...

Сто лет не обновляла этот бложик, пардон.
Вот вам забавная новость. На английском, ага, как обычно.
Некоторые паразиты (токсоплазма, например) в мозгу могут феерически изменять выработку допамина.

Brain parasite directly alters brain chemistry

A research group from the University of Leeds has shown that infection by the brain parasite Toxoplasma gondii, found in 10-20 per cent of the UK's population, directly affects the production of dopamine, a key chemical messenger in the brain.

Their findings are the first to demonstrate that a parasite found in the brain of mammals can affect dopamine levels.

Whilst the work has been carried out with rodents, lead investigator Dr Glenn McConkey of the University's Faculty of Biological Sciences, believes that the findings could ultimately shed new light on treating human neurological disorders that are dopamine-related such as schizophrenia, attention deficit hyperactivity disorder, and Parkinson's disease.

This research may explain how these parasites, remarkably, manipulate rodents' behaviour for their own advantage. Infected mice and rats lose their innate fear of cats, increasing the chances of being caught and eaten, which enables the parasite to return to its main host to complete its life cycle.

In this study, funded by the Stanley Medical Research Institute and Dunhill Medical Trust, the research team found that the parasite causes production and release of many times the normal amount of dopamine in infected brain cells.

Dopamine is a natural chemical which relays messages in the brain controlling aspects of movement, cognition and behaviour. It helps control the brain's reward and pleasure centres and regulates emotional responses such as fear. The presence of a certain kind of dopamine receptor is also associated with sensation-seeking, whereas dopamine deficiency in humans results in Parkinson's disease.

These findings build on earlier studies in which Dr McConkey's group found that the parasite actually encodes the enzyme for producing dopamine in its genome.

"Based on these analyses, it was clear that T. gondii can orchestrate a significant increase in dopamine production in neural cells," says Dr McConkey.

"Humans are accidental hosts to T. gondii and the parasite could end up anywhere in the brain, so human symptoms of toxoplasmosis infection may depend on where parasite ends up. This may explain the observed statistical link between incidences of schizophrenia and toxoplasmosis infection."

Dr McConkey says his next experiments will investigate how the parasite enzyme triggers dopamine production and how this may change behaviour.
http://www.eurekalert.org/pub_releases/2011-11/uol-bpd110411.php

Бисфенол-А - очередные новости

Недавно у нас работе было сооружено нечто из одного из самых источающих бисфенол-А материалов. Удалось уговорить снести ту штуковину, только показав кучу литературы о вреде и коварстве бисфенола-А. Однако, работы весьма противоречивы и достаточное количество авторов утверждает, что вред не так уж и выражен.
И вот очередное сообщение:

Neuropharmacology. 2011 May 5. [Epub ahead of print]

Sex-specific influence of exposure to bisphenol-A between adolescence and young adulthood on mouse behaviors.

Xu X, Tian D, Hong X, Chen L, Xie L.

Source

Chemistry and Life Sciences College, Zhejiang Normal University, 688# Yinbin Road, Jinhua 321004, PR China; Psychology Research Center, Zhejiang Normal University, PR China.

Abstract

Bisphenol-A (BPA) is one of the most common environmental endocrine disrupters and has a wide range of effects on central nervous system. Adolescence is another important developmental period besides the early critical prenatal and neonatal periods. In the present study, we exposed mice to BPA (40, 400 μg/kg/d) between adolescence and young adulthood for 8 weeks and investigated its effects on the non-reproductive behaviors. In open field tests, rearing and grooming sex differences were abolished by BPA exposure. In the elevated plus maze test, the number of open arm entries, the time spent in open arms, and the number of unprotected head dips in the center area were reduced in males but increased in females by BPA at 40 or 400 μg/kg/d, thus eliminating or reversing sex differences in these behaviors. In the Morris water maze task, exposure to BPA at 40 μg/kg/d significantly extended the average escape pathlength to the hidden platform in males, but no significant influence was found in females; thus, the sex differences in spatial learning and memory were abolished. In the step-down test, the latency to step down from the platform 24 h after receiving a footshock was shortened by BPA exposure in males but not in females; thus, a sex difference was induced in passive avoidance memory in mice. These results suggest that long-term exposure to low levels of BPA between adolescence and young adulthood alters characteristic differences in certain non-reproductive behaviors of males and females, including exploration, anxiety, spatial learning and memory, and passive avoidance memory, although no obvious changes were found in the serum hormone levels or in the weights of reproductive organs.

Copyright © 2011. Published by Elsevier Ltd.

PMID:

 

21570416

 

[PubMed - as supplied by publisher]

Феерическое видео о "двойном рождении" кенгуру

Слабонервным, конечно, лучше отвернуться, но ценители смогут в миллионный раз удивиться мудрости природы

Ещё о пчёлах и кокаине. Видео.

В продолжение темы пчёлок-наркоманок. Видео, которое я откопала на http://scienceblogs.com/clock/2008/12/this_is_your_honeybee_and_this.php

http://www.youtube.com/watch?v=lE-8QuBDkkw&eurl=http://scienceblogs.com/clock/2008/12/this_is_your_honeybee_and_this.php&feature=player_embedded

Пчёлки любят кокс?!

Без комментариев... :) Читаем на scientificblogging.com/news_releases/honeybees_cocaine
Since its discovery in the 18th century, cocaine has been a scourge of western society. Strongly stimulating human reward centers in low doses, cocaine is extremely addictive and can be fatal in high doses.

But this potent compound did not evolve to ensnare humans in addiction, it is a powerful insect neurotoxin, protecting coca bushes from munching insects - without rewarding them.

Knowing that foraging honey bees are strongly motivated by rewards (they dance in response to the discovery of a rewarding nectar or pollen supply) and that this behavior is controlled by similar mechanisms to the ones that leave humans vulnerable to cocaine addiction, Andrew Barron from Macquarie University, Australia and Gene Robinson from the University of Illinois at Urbana-Champaign wondered whether bees may be vulnerable to cocaine's allure at the right dose.

Teaming up with Ryszard Maleszka at the Australian National University, Barron set about testing how honeybees respond to cocaine. They publish their results on 26th December 2008 in The Journal of Experimental Biology.

Setting up his hives on a farm just outside Canberra, Barron trained the insects to visit a feeder stocked with a sugar solution. Then he gently applied a tiny drop of cocaine solution to the insect's back, and waited to see how enthusiastically the foraging insects danced when returning to the hive.

Amazingly, low doses of the drug stimulated the insects to dance extremely vigorously. They behaved as if the sucrose solution was of a much higher quality than it really was. The cocaine seemed to be hitting the insects' reward centers, but were they really responding to the drug like humans or was the drug stimulating some other aspect of the insects' behavior to look as if they were becoming addicted?

Working with a team of undergraduate students, Barron tested whether cocaine stimulated the insects' locomotion centers by monitoring their movements after a dose of the drug. The insects behaved normally, so the drug probably doesn't affect their movements. However, when Paul Helliwell tested the bees' sensitivity to sugar solutions, the drugged bees responded more strongly than the undrugged insects, so cocaine was increasing their sugar sensitivity.

But was it only increasing their sensitivity to sugar, or increasing their response to all rewards? Barron offered the drugged insects pollen to see if cocaine increased their sensitivity to other floral rewards and found that the foragers were equally overenthusiastic, dancing as if the pollen quality was much better than it really was.

Finally Barron and Helliwell wondered whether bees that had been on cocaine for a few days had become dependent and went into withdrawal when the drug was withheld. Testing the insects' ability to learn to distinguish between lemon and vanilla scents, they found that the bees were fine so long as their cocaine supply was maintained. But as soon as the drug was withdrawn the bees had difficulty learning the task, just like humans going into withdrawal.

Barron is confident that honeybees are as susceptible to cocaine's allure as humans, and is keen to find out more about the drug's effects. He hopes to identify the neural pathways that it targets to find out more about the mechanisms involved in human addiction and to find out whether the drug has as devastating an effect on honey bee society as it does on human society.

Пингвины-геи крадут яйца у птиц-натуралов! :)

Вот такие реалии животного гомосексуализма... :) Читаю на http://scienceblogs.com/zooillogix/2008/12/gay_penguins_steal_straight_co.phpGay Penguins Steal Straight Couples' Eggs
Category: penguins
Posted on: December 1, 2008 8:02 PM, by Benny Bleiman

A pair of gay penguins at Polar Land in Harbin, north east China has taken to stealing the eggs of straight couples and leaving rocks in place to fool their victims. The penguins, named Anderson Cooper and Clay*** by the zoo keepers, have been outed by their fellow penmates and have since been ostracized by the flock. Fearing for the stress levels of the flock, keepers have taken Anderson and Clay out of their enclosure and segrated them alone in a pen of their own.


"Did you see little miss happy feet the other day? That new bleak gloss was a travesty against all things good in this world!..." "Um, I KNOW it. I mean, wooo-ooooh, wooo-ooooh, someone call the Antarctic Fashion Police!"

When asked about the decision to separate the gay penguin couple, one keeper told the Austrian Times newspaper as reported in the Daily Telegraph, "It's not discrimination. We have to fence them separately, otherwise the whole group will be disturbed during hatching time."

Either way, 51 percent of Californians applauded the zoo's decision. "When it comes to penguin rights, separate but equal sounds good to us," a spokesman for the Church of Jesus Christ of Latter Day Saints from nearby Utah was quoted as saying.

Instances of animal homosexuality are recorded all over the science kingdom (including by us), and prove, once and for all, that when you don't believe in genes, evolution or science, homosexuality is merely a choice of lifestyle.

***The names Anderson Cooper and Clay may not have actually been used by the keepers at the zoo, and may in fact have been invented by me.

Антидепрессанты для домашних питомцев!

Да... До чего дошёл прогресс! :) Информация с http://scienceblogs.com/cortex/2008/07/prozac_pets.php:

Prozac Pets
Category: Life Science
Posted on: July 9, 2008 2:50 PM, by Jonah Lehrer

I don't know how I feel about this new trend of giving household pets human anti-depressants. Here's James Vlahos in the Times Magazine:

The practice of prescribing medications designed for humans to animals has grown substantially over the past decade and a half, and pharmaceutical companies have recently begun experimenting with a more direct strategy: marketing behavior-modification and "lifestyle" drugs specifically for pets. America's animals, it seems, have very American health problems. More than 20 percent of our dogs are overweight; Pfizer's Slentrol was approved by the F.D.A. last year as the country's first canine anti-obesity medication. Dogs live 13 years on average, considerably longer than they did in the past; Pfizer's Anipryl treats cognitive dysfunction so that absent-minded pets can remember the location of the supper bowl or doggy door. For lonely dogs with separation anxiety, Eli Lilly brought to market its own drug Reconcile last year. The only difference between it and Prozac is that Reconcile is chewable and tastes like beef.
On the one hand, it's one of those bourgeois habits that's all too easy to mock. We think we're helping our animals - most pills are prescribed for "separation anxiety" - but we're actually indulging in some reckless experimentation. A dog can't tell us that he'd rather not take the little blue pill, or that he preferred his mindset before we started slipping tricyclics into his doggie bowl. It's the kind of foolishness that makes me wish Evelyn Waugh were still around.

And yet, as a pet-owner, I completely understand the urge to do everything possible to make these animals happy. As I write this post, my African Grey parrot is standing on her perch saying "I love people!" (I'm not joking - that's her favorite refrain.) She feels like a member of the family, so it's easy to understand how, if my vet diagnosed her with some emotional disorder, I'd be tempted to put some Prozac in her foodbowl. (That is, if my vet recommended such a thing.)

In the end, though, I find this paragraph pretty compelling:

Pharmacological treatments, furthermore, are sometimes more for the convenience of owners than they are for the health of pets. When the dog bites, when the cat pees -- "a lot of the 'behavior problems' we see are actually normal behaviors for the animal," Dodman says. Cats aren't mentally ill if they attack a new feline in the household or claw furniture to mark their domain. Food guarding and aggression toward strangers boost a dog's survival rate in the wild but don't cut it in the living room. And both cats and dogs demarcate territory with urine. "If a dog goes to the bathroom on a bush outside, you don't mind as long as it's not your bush," Dodman says. "But when he comes back to the house and lifts his leg on your chair, it's like, 'Is the dog mentally sick?' "