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Postby Danilo » 25 Apr 2006, 15:09

Quanto ao efeito no Fernando:
1- Será que ele teria mesmo cólica sem o remédio?
2- E porque você não acredita na exposição gradual? O rei romano Mitridates já acreditava nisso algumas décadas antes de Cristo. Ele elaborou um plano de beber veneno diariamente, depois de tomar remédios, para se ir se adaptando até que se tornassem inócuos. Afinal ´O que diferencia o veneno de um remédio é a dose´.
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Postby mends » 25 Apr 2006, 17:16

1- Será que ele teria mesmo cólica sem o remédio?


até onde eu sei, criança sempre tem colica se come/bebe algo diferente de leite materno nos primeiros meses.

´O que diferencia o veneno de um remédio é a dose´.


mas é justamente esse o meu ponto!!! Só que a dose "mpinima" se dá com o remédio, não dá pra ter uma exposição mínima a pelo de gato com um gato inteiro cheio de pelos, carai!
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I have been blessed with the power to survive.
After all these years I'm still alive."

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Postby Danilo » 25 Apr 2006, 23:54

Uai, não entendi direito então a frase sua...
E acredito que não dê pra dizer que vc cura a alergia simplesmente aumentando a exposição, que é o que está ocorrendo
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Postby mends » 26 Apr 2006, 09:20

não dá pra curar a alergia deixando ele entrar em contato com o gato até ele se acostumar com o gato.
"I used to be on an endless run.
Believe in miracles 'cause I'm one.
I have been blessed with the power to survive.
After all these years I'm still alive."

Joey Ramone, em uma das minhas músicas favoritas ("I Believe in Miracles")
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Postby mends » 13 Jun 2006, 10:52

Café ajuda na prevenção da cirrose hepática, diz estudo
da France Presse, em Chicago

Beber café pode ajudar a prevenir a cirrose hepática, segundo um estudo publicado nesta segunda-feira nos Arquivos de Medicina Interna da Associação Médica Americana.

O estudo, realizado com mais de 125 mil pessoas, revelou que para cada xícara de café que os participantes do estudo ingeriram por dia, eles mostraram ser 22% menos suscetíveis a desenvolver a cirrose.

O abuso prolongado de álcool é a causa mais comum de cirrose em países desenvolvidos. A doença destrói progressivamente os tecidos saudáveis do fígado e os substitui por tecido lesionado.

A maior parte dos consumidores de álcool, no entanto, nunca desenvolvem cirrose. Para os cientistas, outros fatores que podem influenciar no desenvolvimento da doença incluem genética, dieta, tabagismo e a interação com outras toxinas prejudiciais ao fígado.

Os autores disseram não ter conseguido determinar se a cafeína ou outro ingrediente do café tem o poder de proteger o fígado. A ingestão de chá não demonstrou impacto no desenvolvimento da doença; os cientistas lembraram que a bebida tem menos cafeína que o café.

O responsável pela pesquisa, Arthur Klatsky, e seus colegas do Programa de Cuidados Médicos do Kaiser Permanente Medical Center, em Oakland, Califórnia, analisaram dados de exames de rotina feitos com 125.580 pessoas entre 1978 e 1985 que não apresentavam histórico de doença hepática.

Os participantes responderam a um questionário, fornecendo informações sobre a quantidade de álcool, café e chá ingeridos diariamente no último ano. Alguns fizeram exames para avaliar os níveis de certas enzimas hepáticas liberadas na corrente sangüínea quando o órgão esteve doente ou lesionado.

No fim de 2001, 330 participantes haviam sido diagnosticados com cirrose e 199 com cirrose alcoólica.

Entre os que fizeram exames de sangue, os níveis de enzima hepática foram mais altos entre indivíduos que ingeriram mais álcool, indicando doença ou dano hepático. No entanto, aqueles que beberam álcool e café apresentaram níveis menores, enquanto os que ingeriram álcool, mas não café, apresentaram níveis maiores.

As descobertas não sugerem que os médicos devam prescrever café para evitar a cirrose. "Mesmo que o café seja capaz de proteger o fígado, a primeira medida para reduzir a cirrose alcoólica é evitar ou cessar o abuso de álcool", concluíram.
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Postby mends » 19 Oct 2006, 18:06

...

Image
"I used to be on an endless run.
Believe in miracles 'cause I'm one.
I have been blessed with the power to survive.
After all these years I'm still alive."

Joey Ramone, em uma das minhas músicas favoritas ("I Believe in Miracles")
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Postby mends » 19 Oct 2006, 18:08

...

:lol:

Image
"I used to be on an endless run.
Believe in miracles 'cause I'm one.
I have been blessed with the power to survive.
After all these years I'm still alive."

Joey Ramone, em uma das minhas músicas favoritas ("I Believe in Miracles")
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Postby junior » 20 Oct 2006, 07:48

Muito bom! Foram parar na minha porta :lol: :lol:
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Postby mends » 06 Nov 2006, 18:08

Substance in Red Wine Appears
To Let Mice Live Longer
By DAVID STIPP
November 2, 2006; Page B1

One day last summer, a researcher at a Baltimore lab gently lowered two mice onto a device resembling a spinning rolling pin. Though the rodents were old and fat, they gamely began walking in place like log-rolling lumberjacks.

Then the device sped up and forced them to run hard until they maxed out and harmlessly dropped off. Trembling like a winded octogenarian, one fell after 81 seconds. The other lasted 144 seconds -- almost twice as long.


Three 15-month-old mice from the study were fed, from left to right, a standard diet, a high-calorie diet and a high-calorie diet plus resveratrol. Although it still got fat, the mouse on the right had a 31% lower chance of dying as it aged than the control mouse next to it.
The animals were essentially twins that had lived under identical laboratory conditions. But the more vibrant mouse had been given daily doses of resveratrol, a substance in red wine that some researchers think may slow the aging process.

The mice were part of a new study showing that resveratrol at high doses can block many of the deleterious effects of high-calorie diets in mice, enabling them to survive significantly longer than they normally would on fattening fare. Results showing how much longer mice taking resveratrol may live aren't yet complete because some of them are still alive. But preliminary findings indicate they may have a lifespan extension of 20%.

The study follows several earlier ones showing that resveratrol can boost lifespan in creatures like fruit flies. It represents the first time a substance shown to slow aging in multiple species of lower animals was tested for similar effects in mammals. The results boost hopes that resveratrol, or drugs like it, may eventually be able to ameliorate many diseases of aging, and possibly to extend human life, but that would be many years and many studies away.

The resveratrol study was conducted by researchers at Harvard Medical School and the National Institute on Aging, one of the National Institutes of Health. "The significance of the study on a scale of 10 is 11 in the aging and longevity field," said Nir Barzilai, director of the Institute for Aging Research at Albert Einstein College of Medicine in the Bronx, N.Y., who didn't take part in it.

But he cautioned that the study didn't prove that resveratrol slows aging. That's because blocking the diseases associated with rich diets isn't the same as retarding general aging, which isn't considered a disease. In the study, the mice lived longer, but it isn't certain whether that's because resveratrol slowed aging or only blocked diseases associated with rich diets.

LONGEVITY RESEARCH



Antiaging Researchers Study Calorie Cutback
10/30/06The study's authors are now examining whether resveratrol makes normally fed mice live longer. The data on that should be out next year.

The mice in the Nature study were given much higher doses of resveratrol than anyone could get by drinking red wine, which contains only minuscule amounts of the substance. A person would need to drink more than 300 glasses of wine a day to get the amount of resveratrol the mice got, according to a commentary accompanying the study, which was reported online yesterday by the journal Nature.

Dietary supplements containing concentrated resveratrol extracts, mostly obtained from a plant grown in China known as giant knotweed, let people ingest higher doses than they can get from wine. Various companies, such as Longevinex, based in San Dimas, Calif., sell the supplements over the Internet. But it isn't known what number of such pills might induce health-promoting effects in humans like those observed in mice, because resveratrol hasn't been tested in large, rigorous clinical trials.

Sirtris Pharmaceuticals Inc., a biotech start-up in Cambridge, Mass., co-founded by one of the new study's main authors, recently began testing a resveratrol-based drug in patients with adult-onset diabetes, which is closely linked with fattening diets. Within about a year, the early-stage trial may give a preliminary indication of resveratrol's potential for averting obesity-linked disease in humans. Sirtris says its novel prescription drugs are far more potent than dietary supplements containing resveratrol. Definitive clinical-trial data on the drugs' efficacy probably won't be available for at least several years.

Scientists familiar with the new mouse study generally said that not enough is known about resveratrol to warrant taking the dietary supplements right away. For now, wrote the authors of the Nature commentary, University of Washington biologists Matt Kaeberlein and Peter S. Rabinovitch, "we counsel patience. Just sit back and relax with a glass of red wine."

What has sparked controversy but most interests researchers like Dr. Barzilai about the study are signs that the compound engages the same antiaging mechanisms that calorie restriction does.

Calorie restriction, or CR, entails cutting normal calorie intake by a third or so to slow aging. Discovered in the 1930s, it has been shown to extend longevity by 30% to 40% in animals. Monkey and human studies suggest it can probably also extend human longevity. But its hunger-inducing regimen is too demanding for most people. (Thus, the standard joke about it: Even if it doesn't extend your life, it will make it seem longer.)

Several other substances have shown hints of mimicking CR. A widely used diabetes drug called metformin, for example, activates many of the same genes that CR does. But resveratrol stands out for two reasons: It is the first compound shown to boost lifespan in widely diverse species -- there are four so far -- and it is a naturally occurring molecule that people have long ingested, suggesting that it is safer to take than other potential CR-imitating compounds.


An aged mouse in Dr. Sinclair's Harvard lab like those in the study.
Hopes that resveratrol might yield CR's gain without pain were first raised in 2003 by Harvard Medical School biologist David Sinclair, who led a study showing that the compound boosted yeast cells' lifespan by 70%, apparently by mimicking CR. The finding led to speculation that resveratrol's CR-like effects might already be evident in people in the form of the "French paradox," under which France's famously bibulous citizens have anomalously low rates of cardiovascular disease despite their fatty, high-calorie diets.

Dr. Sinclair has become the leading proponent of the idea that resveratrol mimics the effects of CR. His theory is controversial, and some researchers assert that his interpretation of existing data on the issue is wrong and that resveratrol's mode of action hasn't been pinned down.

Studies that followed those on yeast cells have shown that resveratrol has antiaging effects in roundworms, fruit flies and a species of short-lived fish. They set the stage for the new mouse study, spearheaded by Dr. Sinclair.

The researchers put the mice on high-calorie diets designed to mimic the kind of fattening food many Americans eat. The study demonstrated that while the mice gained weight on their rich diets, resveratrol largely protected them from adult-onset diabetes, the buildup of harmful fatty deposits in the liver, heart-muscle degeneration and other fallout from the rich diets. The report "suggests that guilt-free gluttony might not be a fantasy," wrote the authors of Nature's commentary.

Still, the study's findings are "very important" because they suggest that resveratrol and similarly acting drugs may offer "considerable benefits" for people with obesity-linked diseases, said Massachusetts Institute of Technology biologist Leonard Guarente. Dr. Guarente co-founded Elixir Pharmaceuticals Inc., a Cambridge, Mass., biotech company that competes with Sirtris, which Dr. Sinclair co-founded to capitalize on his research.

The study's findings paralleled those obtained in another investigation of resveratrol's effects in mice on fattening diets that Sirtris reported at a recent scientific meeting.

Besides lowering the risk of diabetes, according to Sirtris's rodent data, resveratrol and like-acting drugs may limit weight gains from rich diets. (Sirtris's chief executive, Christoph Westphal, is married to a reporter for this newspaper.)

Resveratrol pills for people haven't been tested in large clinical trials, so their efficacy isn't proven, nor is it clear what dose would yield desired effects. Still, Dr. Sinclair believes that long-term ingestion of relatively small doses of resveratrol via dietary supplements may help lower the risk of various diseases.

Resveratrol is considered safe at the modest doses available in the dietary supplements. But massive doses given to rats induced signs of kidney damage, anemia, diarrhea and other side effects, according to a 2002 toxicity report on resveratrol by the National Institute of Environmental Health Sciences.

The toxic doses were roughly equivalent to a person taking many thousands of resveratrol pills a day. The study noted that there were no observable adverse effects in rats at doses comparable to a human taking hundreds of the pills daily, a dose far higher than that used in the study described in Nature.

Resveratrol can inhibit formation of new blood vessels in mice with skin wounds, according to the federal institute's safety study. That could potentially retard wound healing. But it may also have benefits by blocking tumor growth. Resveratrol may also inhibit blood-clotting, according to some studies, potentially risky for people undergoing surgery.

Several of the new study's findings support Dr. Sinclair's view that resveratrol mimics the effects of CR. One of the most striking results was the dramatic edge in running endurance among mice on resveratrol compared with their undosed peers. The longer mice were on resveratrol, the perkier they got. After taking it for a year beginning in middle age (the rodents generally live two to three years), elderly mice had about twice the running endurance of undosed peers. Such late-life sprightliness is also observed in old mice long subjected to CR.

Last spring, Italian scientists reported similar vigor in aged fish treated with resveratrol. The substance also boosted the animals' life span by more than 50%. Another research group, whose data aren't yet published, has reportedly seen the same effect in mice on high doses of resveratrol.

Recent studies by Dr. Sinclair's group and others suggest one reason why this energizing occurs: Resveratrol and other compounds that stimulate an enzyme called SIRT1 engender new mitochondria, tiny dynamos within cells that churn out energy for everything from moving muscles to sending signals between neurons. CR is thought to do the same thing, says Eric Ravussin, an authority on CR at the Pennington Biomedical Research Center, an obesity research center affiliated with Louisiana State University, and an adviser to Sirtris.

Dr. Ravussin adds that the fresh mitochondria appear to spew fewer damaging "free radicals," molecules whose DNA-fraying action has been linked to aging, than do the older mitochondria they replace. "It's like replacing the engine of a polluting gas guzzler with an efficient, cleaner-burning new one," he says.
"I used to be on an endless run.
Believe in miracles 'cause I'm one.
I have been blessed with the power to survive.
After all these years I'm still alive."

Joey Ramone, em uma das minhas músicas favoritas ("I Believe in Miracles")
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Postby mends » 22 Nov 2006, 16:51

:lol: Image
"I used to be on an endless run.
Believe in miracles 'cause I'm one.
I have been blessed with the power to survive.
After all these years I'm still alive."

Joey Ramone, em uma das minhas músicas favoritas ("I Believe in Miracles")
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Poluição em São Paulo

Postby Danilo » 24 Nov 2006, 12:59

Para as 18 milhões de pessoas que moram na Grande São Paulo, o problema da poluição atmosférica fica relegado a uma posição secundária diante de tantos outros.

Paulo Saldiva, do Laboratório de Poluição Atmosférica Experimental da FMUSP estuda há 30 anos os efeitos da poluição sobre a saúde humana. Com sua experiência, afirma seguro: "A poluição é um problema de saúde pública. Em São Paulo, o impacto sobre cada habitante, por dia, é equivalente a fumar três cigarros.

Após centenas de experimentos realizados em seu laboratório, Saldiva apresenta dados alarmantes sobre a poluição do ar: no Instituto do Coração, a cada 100 consultas ao pronto-socorro, 12 estão associadas a problemas resultantes da poluição do ar; De 5% a 6% das mortes "naturais" de idosos são aceleradas pela poluição, o que é considerado um índice alto pelos médicos; O risco de ser vítima de câncer de pulmão morando em uma cidade como São Paulo é 10% maior do que em outros locais.

Diante da relação bem estabelecida entre poluentes e saúde pública, novos desafios científicos se colocam, e eles não são poucos. Ainda não se sabe bem quais substâncias químicas presentes no ar invisível são realmente tóxicas. Quando os piores inimigos forem identificados, ainda restará saber como eles agem no organismo. Vencidas essas duas etapas, estratégias mais eficazes de redução do problema poderão emergir.

Nelson Gouveia, professor da FMUSP ainda alerta para os efeitos crônicos: "Uma coisa é a poluição aumentar e você ter uma exacerbação da doença e morrer. Isso conseguimos perceber com facilidade. Outra coisa é você respirar essa poluição por anos e anos e ela ir prejudicado aos poucos o organismo, até gerar um efeito agudo. Existe uma contribuição crônica que não temos como medir. Isso seria muito difícil, porque envolveria estudos acompanhando pessoas por muito tempo. Esse tipo de estudo ainda não existe no Brasil". Os chamados estudos longitudinais são essenciais para que se tenha uma medida mais exata do efeito da poluição. Eles seriam equivalentes a ter todo um filme nas mãos, em vez de apenas algumas fotografias de um evento.

E uma preocupação de São Paulo são as motocicletas. Com o aumento anual da frota, deve-se começar a pensar em como reduzir a poluição causada por esse tipo de veículo, diz Saldiva. Segundo o pesquisador, uma moto emite até 20 vezes mais poluentes por quilômetro que um carro novo!

De maneira semelhante às pesquisas médicas, o componente tecnológico da equação sugere estratégias que podem ser adotadas. A melhoria dos combustíveis, levando em conta fatores ambientais, é um imperativo para futuro próximo. Se o diesel, por exemplo, continuar sendo utilizado nos níveis atuais, além de tudo por uma frota antiga e ineficiente, a redução de poluentes conseguida nos últimos 20 anos graças à tecnologia poderá ser compensada pelo aumento do consumo em apenas meia década.

(matéria completa em ScientificAmericanBrasil)
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Postby mends » 07 Dec 2006, 08:07

The Physical Effects of Multitasking
By SUE SHELLENBARGER
December 7, 2006; Page D3

Q: You've written that too much multitasking can leave the mind and body marinating in stress hormones. Can you elaborate on the physiological effects?

--H.N., Dayton, Ohio

A: People's responses to stress differ; some can multitask a lot without any adverse effects, while others become overwhelmed, says Diane Miller, head of the chronic stress and neurotoxicology laboratory at the National Institute for Occupational Safety and Health. Among those who respond strongly, two "emergency hormones," adrenaline and cortisol, are secreted at elevated levels to prepare the body for defensive action. Adrenaline causes the heart and respiration rates to speed up and sharpens the senses, in a "fight or flight" response. Cortisol causes the liver to release extra glucose for energy, Dr. Miller says; it also can "damp down" your immune system, a response that can be helpful in marshalling needed energy short-term, but that can jeopardize your health if it continues too long.

Brief or infrequent stress responses pose little risk. But when a person responds this way habitually or over long periods, the risk of injury or disease rises. Evidence is growing that some people's stress response plays a role in such chronic health problems as psychological ailments or cardiovascular or musculoskeletal disorders, NIOSH says.
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I have been blessed with the power to survive.
After all these years I'm still alive."

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Postby mends » 04 Jan 2007, 18:36

a curpra num é nossa :blink:, é dos micóbrio! :lol: :lol:

Obesity and bacteria

Greedy guts?

Jan 4th 2007
From The Economist print edition


Every week seems to bring a new theory about why people are getting fatter. The latest is that intestinal microbes are partly to blame



David Simonds






ALTHOUGH most people prefer not to think about it, human guts are full of bacteria. And a good thing, too. These intestinal bugs help digestion, and also stop their disease-causing counterparts from invading. In return, their human hosts provide them with a warm place to live and a share of their meals. It is a symbiotic relationship that has worked well for millions of years.

Now it is working rather too well. A group of researchers led by Jeffrey Gordon, of the Washington University School of Medicine, in St Louis, has found that some types of microbes are a lot better than others at providing usable food to their hosts. In the past, when food was scarce, those who harboured such microbes would have been blessed. These days, paradoxically, they are cursed, for the extra food seems to contribute to obesity. Worse still, these once-benign microbes have even subtler effects, regulating the functioning of human genes and inducing the bodies of their hosts to lay down more fat than would otherwise be the case.


Dr Gordon's research is outlined in a paper published in this week's Proceedings of the National Academy of Sciences (PNAS) and two others published last month in Nature. In the Nature papers, he and his team reported that obese people have a different mix of gut microbes from that found in lean people—a mix that is more efficient at unlocking energy from the food they consume. Although individuals can harbour up to a thousand different types of microbes, more than 90% of these belong to one or other of two groups, called Bacteroidetes and Firmicutes. The researchers sequenced bacterial DNA from faecal samples taken from volunteers and discovered that those who were obese had a higher proportion of Firmicutes than lean people did.



Bugs in the system
This also turned out to be true in mice, and working with these rodents, the researchers discovered that the types of Firmicute found in obese animals are more efficient at converting complex polysaccharides (a form of carbohydrate that mammals have a hard time digesting by themselves) into simple, usable sugars such as glucose. In effect, the Firmicutes made more energy available from the same amount of food. The researchers were even able to make mice that had been raised in a germ-free environment fatter or thinner by colonising their guts with microbes from either obese or lean mice.

It sounds simple enough. Unfortunately, further probing showed that the story is a little more complicated, for Dr Gordon did not merely count the gut bacteria of fat and thin people—he then put some of the fat ones on a diet. As these once-obese humans lost weight over the course of a year, their mix of gut microbes changed to reflect their new, svelte status. Why this happened is not clear. It does not seem to have been a result of the composition of the diet, since the effect was the same whether people lost weight with a low-fat diet or a low-carbohydrate diet. Nevertheless, this part of the experiment suggests it is weight that determines gut biodiversity, not the other way round.

The paper published in PNAS, though, supports the idea that the bacterial mixture is cause not effect, by adding yet another element to the story. In this study, Dr Gordon took normal mice and germ-free mice, and fed both groups a “Western” diet that was high in fat and sugar. The normal mice gained weight; the germ-free mice stayed lean.

Part of the reason was that the normal mice had microbes that made more useful sugar available. But the researchers looked more closely and found that there was even more going on. By comparing the two kinds of mice, they discovered that the gut microbes in the regular mice were tinkering with their hosts' metabolisms, regulating them in at least two different ways.

First, they suppressed production by the mice's bodies of a substance called fasting-induced adipose factor. This encouraged the mice to store fat. Second, they caused lower levels of another substance, called adenosine monophosphate-activated protein kinase, which made it harder for them to burn fat that they had already accumulated. The upshot is that gut microbes not only release energy from food, they also encourage bodies to store that energy as fat and to keep the fat on.

The practical upshot of this is hard to see at the moment. But if these two suppression mechanisms could, themselves, be suppressed, that might stop people putting on weight. The findings do, however, emphasise how profound the relationship is between people and their gut bacteria. These bacteria can be thought of as an additional digestive organ. Alternatively, humans might view themselves as a sort of collective organism—a human casing surrounding a vast colony of microbes. It is just a pity that this colony is working so hard on behalf of its casing that, in an era when food comes from the supermarket rather than the savannah, the result is rather too good.
"I used to be on an endless run.
Believe in miracles 'cause I'm one.
I have been blessed with the power to survive.
After all these years I'm still alive."

Joey Ramone, em uma das minhas músicas favoritas ("I Believe in Miracles")
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Postby Danilo » 17 Jun 2007, 14:40

Ah se eu tivesse disponível a tecnologia do final desse século pra tratamento dental...

Cientistas recriam dentes a partir de células-tronco
(Clare Wilson - New Scientist)

Quando mencionamos bioengenharia, a última coisa em que as pessoas pensam são dentes. Órgãos vitais como o fígado, os rins ou o coração - os que matam o paciente caso deixem de funcionar, são uma coisa. Mas, dentes? Alguns poucos grupos de pesquisadores acreditam que, no momento, a odontologia apresente alguns dos desenvolvimentos mais animadores na área da bioengenharia. Paul Sharpe, diretor de desenvolvimento craniofacial no King's College de Londres diz que "O objetivo é que, quando você for ao dentista, tenha células extraídas e trabalhadas por engenharia genética. Depois, as inserimos no lugar onde você precisa de um dente e logo um dente novo cresce".

Em um mundo cheio de abalos e sem cura absoluta para a decadência dentária, haverá sempre dentes precisando de substituição. Mas, encaremos os fatos: as opções disponíveis são menos que ideais. Dentaduras são desconfortáveis, canhestras e inconvenientes. Implantes de titânio de última geração implicam em trabalho odontológico pesado e sangrento, e ainda assim não são exatamente como dentes reais. Já está mais que na hora de surgirem alternativas melhores.

A bioengenharia avançou bastante nos últimos anos, e com isso surgiu a possibilidade de criar órgãos do zero. Os dentes são um alvo atraente para os bioengenheiros. Eles não mantêm as pessoas vivas, como o fígado e o coração, de modo que se um dente não crescesse de maneira correta, o dentista poderia simplesmente extraí-lo e começar de novo -algo bem menos temerário do que implantar um fígado criado por engenharia genética e vê-lo deixando de funcionar. Além disso, chegar ao local do implante não requer uma cirurgia de grande porte -apenas o familiar "abra bem a boca".

E existe uma boa chance de que a vaidade humana garanta um suprimento constante de dinheiro para a pesquisa necessária. O imenso mercado norte-americano de odontologia cosmética testemunha o anseio de pelo menos um país pelo sorriso perfeito. As empresas de biotecnologia já estão salivando diante da idéia de conquistar uma fatia dessa torta multibilionária. Os fundadores da Dentigenix, uma empresa norte-americana criada em novembro, planejam adquirir licenças para técnicas desenvolvidas por outros pesquisadores que trabalham com reparos dentários e regeneração de dentes integrais. O executivo chefe do grupo, Christopher Somogyi, que costumava trabalhar no ramo de capital para empreendimentos biotecnológicos, diz que a "revolução na engenharia de tecidos que temos na medicina ainda não avançou de maneira equivalente na odontologia. Nas conferências, quando um cardiologista entra na sala, toda a atenção é dedicada a ele". Mas, acrescenta, "o número imenso de procedimentos potenciais" faz da odontologia uma área ideal de investimento.

Em Londres, depois de muitos anos de trabalho com células-tronco embriônicas, Sharpe está agora usando células-tronco adultas, ainda que não revele quais. E está cultivando dentes em soluções de cultura, e não no interior de animais. Ao descobrir as moléculas sinalizadoras corretas, ele persuadiu diversos tipos de célula-tronco de camundongos adultos a se desenvolverem como células progenitoras de dentes e como dentes imaturos.

O próximo passo para ele é implantar os brotos de dentes em mandíbulas de animais. Ele calcula que o broto dentário em desenvolvimento atrairá suas próprias conexões nervosas e sangüíneas, e desenvolverá cimento e ligamentos próprios. "Assim que se dá o primeiro empurrão, eles crescem sozinhos", diz.

Ainda que tenha publicado poucos detalhes de suas técnicas, diversos pesquisadores no ramo acreditam que Sharpe seja o cientista a observar. Sharpe confia em que suas técnicas atingirão estágio clínico, e criou uma empresa, a Odontis, para explorá-las. Ele não se preocupa muito com as críticas de que o desenvolvimento de dentes é complexo demais para ser emulado. "Sim, é complicado", diz. "Mas estamos permitindo que as rotas naturais de desenvolvimento embriônico trabalhem em nosso favor".
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Postby mends » 26 Jul 2007, 15:25

a culpa é de vocês... :lol:

Can Your Friends Make You Fat?
By JENNIFER LEVITZ
July 26, 2007; Page D1

Friendship offers support, laughter -- and the occasional spare tire.

Just ask Jamie Tighe, a 35-year-old stay-at-home mother in Franklin, Mass. In college, Ms. Tighe and her friends "all gained weight together." Then she and her best friend added more poundage over Margaritas and chips. Her appetite -- and her avoirdupois -- spread to her husband, Kevin Tighe, who she says had been "rip cut" when they married.

"He just started putting on the weight," she says. "He didn't even care. He'd call it his Buddha belly and make fun of it, rub it." Mr. Tighe, a 38-year-old technology salesman, says it's true. "I ballooned up," he says. "If someone else is doing it, you don't feel as bad about it."

The Tighes' mutual overeating isn't unusual. A study in this week's New England Journal of Medicine finds that social networks have an even greater effect on chances of becoming obese than genes do. The findings may help explain why obesity is rising in America despite widespread dieting and other weight-loss techniques, and why people's best efforts to slim down on their own are so often short-lived. They also suggest that public health initiatives to fight obesity should take social networks into account, and work with overweight people in groups, as organizations such as Weight Watchers International Inc. have done for years.

Dr. Nicholas Christakis at Harvard medical school, lead author of the study, says the results indicate that behavioral "norms" shift depending on how people in a social circle look and act, even if they only meet once a year. "People might say, 'Look, Christakis is getting fat. It's okay for me to be obese as well." Social contacts propelled weight gains even among individuals a thousand miles apart, indicating that social proximity overrides geographic proximity.

"It's become very fashionable to speak of an obesity epidemic," says Dr. Christakes. "But we wondered, in fact, is obesity really an epidemic, with person to person transmission? Was there a kind of social contagion?"

The study found that indeed there was. A person's chance of becoming obese jumped 57% if he or she also had a friend who became obese during a given time. If one adult sibling became obese, the chance that the other would follow suit increased by 40%. These findings were particularly true if siblings and friends were of the same sex -- since, researchers say, people are more influenced by those they resemble than those they do not. Indeed, the chance of becoming obese rose 71% if it was a same-sex friend who gained the weight.

The study examined 12,067 people who underwent repeated body measurements over 32 years as part of the Framingham Heart Study, considered the crown jewel of epidemiological studies.

Over the years, each participant in the heart study was asked to list close friends and workplace contacts to allow doctors to track them down. Many of these friends, it turned out, were also part of the study, so their information was available to researchers.

From these contacts, researchers examined 38,611 family and social relationships, charting associations between a person's weight gain and the weight gain among his or her social circle, including relatives, friends, and co-workers.

Among married couples, the study found, if one spouse became obese, the likelihood that the other spouse would do the same increased by 37%. The study also suggested that most people don't keep up with the Joneses when it comes to weight gain since it found no effect from the obesity of neighbors who aren't part of the social network.

The study is part of a larger trend in science and social science to examine the effect of networks, from the role that interconnected neurons play in cognition, to even networks of terrorism. There's evidence, for instance, that political attitudes are shaped by social circles, and that when it comes to sexual behavior, teens are more influenced by their immediate friends than by the most popular group at school or by the media.

"Networks are really important for the transmission of ideas and values," says Katherine Stovel, a University of Washington sociology professor who studies networks. "People come to resemble one another." But, she cautioned, "I don't want anybody to read this and think about dropping friends because they're fat."

MORE



• Harvard's statement
• Video interview with Nicholas ChristakisTraci Joyce, a 39-year-old lab technician at a regional cancer center in Greensboro, N.C., says she and many of her co-workers need to "lose a few pounds." Yet they push pastries, cookies, cakes and chocolate turtles on each other. "They'll try to sabotage you sometimes," she says. "Oh come on, you can have some. It'll be alright."

Some doctors are excited about the new obesity study from a public health perspective because if weight gains can spread through a network, then presumably, so can healthful habits. Medical and public-health interventions in obesity might be more cost-effective than previously thought, the study's authors wrote, "since health improvements in one person might spread to others."

In an editorial in the New England Journal of Medicine, Albert-Laszlo Barabasi, of the University of Notre Dame's Center for Complex Network Research, urged the medical profession to take the network effect seriously. He wrote that "the role of links and connections does not stop here," and that such studies "should start to affect medical practice."

Many communities are already harnessing the force of networks to reduce obesity. In Guilford County, N.C., where 62% of residents are obese, local health officials held a community-wide weight loss program this spring. Called the Guilford County Mayors' Challenge, the program joined together citizens who wanted to lose 10 pounds in 10 weeks. The group chatted online about exercise routines, and exchanged healthful recipes. Ten weeks later, 150 people had shed 1,450 pounds.

Toni Anzalone Zirker, a 50-year-old substitute teacher in Greensboro, Guilford's county seat, says she originally tried to lose weight with a group of friends. "I tried to call several friends -- they didn't follow through," she says. But when she joined the Mayors' Challenge, she found an instant support group, which motivated her. Someone would write online, she says, "I gotta take off this pork belly." She says she'd think, "yeah, I can relate to that."

"You didn't feel all alone out there," she says.

And ultimately, a group setting rescued Jamie and Kevin Tighe, the Franklin, Mass., husband and wife who had literally grown as a couple after marriage.

Ms. Tighe, struck with the desire to be healthy for their two daughters, started dieting first. Mr. Tighe was uneasy with her new attitude. "He'd say, 'Oh god, you're not fun anymore," she says. "You don't get the appetizers."

Mr. Tighe says he was merely feeling guilty for eating fatty foods while she was eating salad. But sure enough, as she began to trim down, he wanted to do the same. The two became active in a chapter of Weight Watchers; Ms. Tighe leads local meetings, and both are at healthy weights. Mr. Tighe, who's shed 60 pounds since 2005, says having a support system "got my butt off the couch."

Write to Jennifer Levitz at jennifer.levitz@wsj.com
"I used to be on an endless run.
Believe in miracles 'cause I'm one.
I have been blessed with the power to survive.
After all these years I'm still alive."

Joey Ramone, em uma das minhas músicas favoritas ("I Believe in Miracles")
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