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Thursday, April 29, 2010

April 21 - Demasculinisation and other side effects‏

Dear Friends,

Be Well.


Demasculinisation and other side effects

21 April 2010

by Shanna Swan and Bernard Weiss

Cosmos Online

Concrete jungles are not the only part of our environment that is man made. There are also thousands of man-made chemicals and this chemical environment is a vast, unchecked experiment on human health.

Plastic baby products

In 2005, Shanna Swan and her colleagues discovered that the phthalates in plastic baby products and toys led to a variety of penile disorders, including reduced size.

Credit: iStockphoto

We are all unwittingly participating in a massive experiment without our consent. We are exposed to hundreds (and perhaps thousands) of man-made chemicals whose impacts on our health have barely been considered. But increasingly we are learning that many can threaten human health.

Of particular concern are those chemicals that modify how our hormones function and the multiplicity of complex signals that our bodies need to function properly. These chemicals are known as endocrine disruptors, and only now are we becoming aware of their profound influence on how we feel, how we function, how healthy we are, and how little we know about them.

Rachel Carson stirred the first notable misgivings about our contaminated environment in her 1962 summons to action, Silent Spring. She provoked us to listen to her sentinels: "…On the mornings that had once throbbed with the dawn chorus of scores of bird voices there was now no sound; only silence lay over the fields and woods and marsh."

Carson wrote about wildlife, where we saw the earliest clues to what we had wrought by contaminating our environment. Humans are not exempt from these consequences.

Our current understanding of how these chemicals can alter human health began with the discovery of the disastrous impacts of a drug, diethylstilbestrol, or DES. The FDA approved DES for the prevention of miscarriage in 1947.

It was marketed worldwide despite a well-done clinical study showing it was therapeutically ineffective. It proved to be a biological time bomb. Daughters of women who had been prescribed DES appeared to be healthy.

But, after undergoing the hormonal changes of adolescence, a majority of those who had been exposed early in pregnancy developed a multitude of adverse effects. They showed abnormalities of the reproductive tract; they had problems conceiving and, if they succeeded in becoming pregnant, they were far less likely to carry their pregnancy to term.

Most seriously, and fortunately far less often, they developed a rare form of vaginal cancer. New evidence is now suggesting that these reproductive problems can also affect the third generation.

DES is a synthetic estrogen. Other estrogenic chemicals were already known to pervade the environment; they had been targeted as the source of the eggshell thinning that had decimated bird populations such as the bald eagle.

It was a natural step to begin searching for other kinds of effects. They were not hard to find. And they provoked intense concern about human health.

These concerns culminated in a conference, held in the Wingspread Conference Centre in Wisconsin, in 1991. Its theme became the impetus for what became a prodigious research effort: chemically induced alterations in sexual development: the wildlife/human connection.

The Wingspread consensus statement listed the suspect chemicals. It described the wildlife populations that had been afflicted by chemical exposures; it linked these effects to human health by showing how we, too, are exposed; it called for remediation to prevent disorders in human populations.

The Wingspan consensus also conceived the term, 'endocrine disruption', to describe the mechanisms by which these chemicals acted. They act by mimicking and displacing natural hormones, by antagonizing their effects, by changing how the body synthesizes them, by changing their concentrations in the body.

Wingspread alerted the scientific community. But the lay public remained largely unaware of these issues until the publication in 1996 of a seminal book that was to become an international best seller: Our Stolen Future, by Theo Colborn, Diane Dumanoski and John Peterson Myers.

Our Stolen Future, now translated into 20 languages, aroused a silent public, led to U.S. Congressional hearings and increased funding for research and transformed the science of toxicology.

What is new about this new science? Endocrine disruptors are stealth chemicals. Unlike smoking, or DES, these chemicals are silent; they enter our bodies without our knowledge. Exposure to many of these chemicals is ubiquitous; the Centers for Disease Controls now tests regularly for nearly 150 chemicals and a majority are detectable in us.

Their effects are subtle and careful (and expensive) studies are required to demonstrate these effects. The FDA withdrew approval of DES by pregnant women on the basis of only eight cases of vaginal cancer in young women. Demonstrating effects of environmental endocrine disruptors requires far larger studies and much more subtle endpoints.

We are only now beginning to appreciate how broadly men and women differ in how they develop, in their patterns of disease and responses to treatment. Many of these differences are tied to innate hormones and other chemical signals within the body.

So it should not surprise us that endocrine disrupting chemicals can be expected to exert their effects differently in males and females. This understanding guides our current research and has led us to choose measures for our studies that are sensitive to these differences.

This current research is often guided by findings in rodents (unlike DES research where animal studies followed the discovery of the human catastrophe). In rodents we can identify subtle changes to the target organ—the reproductive tract, the brain—but in humans we must rely on what we can measure without inflicting physical harm.

And, even with animals, maleness and femaleness are not just about the genitals. Hormonal differences pervade our physiology; differences in thyroid function, immune function and, of course, behaviour.

Consider a single class of endocrine disruptors: the phthalate esters. Phthalates are produced in prodigious quantities, on the order of several millions of kilograms annually. They make plastic soft and serve as plasticizers for polyvinyl chloride products ranging from medical tubing to shower curtains.

They are found in children's toys and teething rings (now banned in the EU and U.S.), cosmetics, enteric coatings for medications, vinyl flooring and wallpaper, food packaging and many other products. The exposure sources include food, drinking water, and house dust.

Phthalates are used as 'inert' ingredients in pesticide formulations. Toxic dumps are contaminated by phthalates and they find their way into aquatic environments.

Phthalate comprise a large chemical class, and some are more toxic than others. Those of most concern have been shown to be anti-androgenic; that is, they have the potential to interfere with or reduce testosterone.

If you administer phthalates to a pregnant rodent, the male offspring exhibit a variety of reproductive tract anomalies such as undescended testes, a cleft phallus (hypospadias), and indices of feminisation such as retained nipples.

They also show a shortened anogenital distance, the distance between the anus and the genitals. Toxicologists have traditionally used this measure to decide on the sex of newborn pups, since it is twice as long in males as in females.

As a group these changes induced by prenatal phthalate exposure have been termed the 'phthalate syndrome', which is produced by the inhibition of testosterone secretion by the foetal testis during a critical developmental period.

The usual testing paradigms in toxicology administer high doses of chemicals so that it is possible to identify adverse effects using small numbers of animals. Moreover, these chemicals are tested one at a time, and by a single route of exposure (usually oral).

We are recognising that humans are exposed to a mixture of chemicals, for example more than a dozen phthalates and their breakdown products (metabolites), and that these enter our bodies orally, dermally, by inhalation and even intravenously (for example, newborns in the neonatal intensive care nursery). These exposures can act together, producing effects that can be missed when they are examined singly.

Until recently, phthalates were not considered a threat to human health because we are exposed to much lower levels than those used in animal laboratory tests.

Not until 2005, that is. In an article now considered a landmark publication, one of us, Shanna Swan, showed that boys born to women with higher levels of phthalate metabolites in their urine exhibited shorter anogenital distances and reduced penile size.

The result aroused keen worldwide interest because these women had only been exposed to ordinary environmental levels of phthalates. It triggered a new burst of research. The findings were confirmed and extended.

It led governments and regulatory agencies to ban phthalates in toys and teething rings. The Australian government banned children's toys that contain over 1% diethylhexyl phthalate in January 2010.

Testosterone doesn't just govern genital structure. It also governs brain anatomy. Male brains differ from female brains. The differences arise from the actions of foetal testosterone.

It is the hormone that moulds and organises the brain, and this brain structure has been clearly shown to affect behaviour. Testosterone is the main source of differences between how men and women behave. Its effects can be seen from magnetic resonance images of male and female brains.

If male and female brains are different, should we expect to see maternal phthalate levels related to differences in children's behaviour? We posed that question to the same population of women whose children contributed the anogenital distance data. This time, we asked the women about their child's behaviour.

We chose a behaviour that we know differs between boys and girls: how they play and what they choose to play with. We asked that question by using a standardised questionnaire called the Preschool Activities Inventory.

It lists items such as preferred toys (trucks versus dolls, for example), modes of play (wrestling versus playing quietly), and other activities that are sex-linked.

In our 2009 article, published in International Journal of Andrology, we showed that higher phthalate concentrations in the mother's urine predicted less masculine play patterns in their boys.

It demonstrated that the brain, like the genitals, can be transformed by phthalates. This is only the beginning of the story. Phthalates are undergoing more study because we still don't know about the full scope of their effects.

And we have embarked on a new research program, this time devoted to Bisphenol A (BPA). It is a plastic ingredient found in baby bottles, can linings, and many other products. We are all exposed to BPA, and carry it in our bodies.

Bisphenol A has been banned from baby bottles in Canada. The United States Food and Drug Administration, originally lethargic about any action, has now been induced to more carefully assess the evidence pointing to its health threats. Many Australians would like to see their own government out in front on the issue.

Our own interests lie in how bisphenol A might alter brain development. It is an estrogen, like DES (as was demonstrated for both chemicals by Sir Charles Dodds in the 1930s). We are asking the question in both rats and humans. And we are starting to examine bisphenol A in a mixture with phthalates and other chemicals.

This research, is a test case, so to speak, of how we can coordinate scientists from many disciplines to join our efforts to address the critical question before us; what are the human health effects of this massive experiment in which we are all unwittingly participating?

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How to Digitally Record/Video a UFO sighting:

Como registar digitalmente ou gravar um vídeo de um avistamento de um UFO:

Stabilize the camera on a tripod. If there is no tripod, then set it on top of a stable, flat surface. If that is not possible lean against a wall to stabilize your body and prevent the camera from filming in a shaky, unsteady manner.

Estabilize a camera com um tripé. Se não tiver um tripé, então coloque-a em cima de uma superfície estável. Se não for possível, então encoste-se a uma parede para estabilizar o corpo e evitar que a camera registe de maneira tremida e instável.

Provide visual reference points for comparison. This includes the horizon, treetops, lampposts, houses, and geographical landmarks (i.e., Horsetooth Reservoir, Mt. Adams, etc.) Provide this in the video whenever is appropriate and doesn’t detract from what your focus is, the UFO.

Forneça pontos visuais de referência para comparação. Isso inclui o horizonte, cimo das árvores, postes de iluminação, pontos de referência geográficos (como o Reservatório de Horsetooth, Mone Adams, etc) Forneça esses pontos no vídeo sempre que for apropriado e não se distraia do que é o seu foco, o UFO/a Nave.

Narrate your videotape. Provide details of the date, time, location, and direction (N,S,E,W) you are looking in. Provide your observations on the weather, including approximate temperature, windspeed, any visible cloud cover or noticeable weather anomalies or events. Narrate on the shape, size, color, movements, approximate altitude of the UFO, etc and what it appears to be doing. Also include any unusual physical, psychological or emotional sensations you might have. Narrate any visual reference points on camera so they correlate with what the viewer will see, and thereby will be better able to understand.

Faça a narração do vídeo. Forneça pormenores sobre a data, hora, local e direcção (Norte, Sul, Este, Oeste) que está a observar. Faça observações sobre as condições atmosféricas, incluindo a temperatura aproximada, velocidade do vento, quantidade de nuvens, anomalias ou acontecimentos meteorológicos evidentes. Descreva a forma, o tamanho, a cor, os movimentos, a altitude aproximada onde se encontra o UFO/nave, etc e o que aparenta estar a fazer. Inclua também quaisquer aspectos pouco habituais de sensações físicas, psicológicas ou emocionais que possa ter. Faça a narração de todos os pontos de referência visual que o espectador irá ver e que, deste modo, será capaz de compreender melhor.

Be persistent and consistent. Return to the scene to videotape and record at this same location. If you have been successful once, the UFO sightings may be occurring in this region regularly, perhaps for specific reasons unknown, and you may be successful again. You may also wish to return to the same location at a different time of day (daylight hours) for better orientation and reference. Film just a minute or two under “normal” circumstances for comparison. Write down what you remember immediately after. As soon as you are done recording the experience/event, immediately write down your impressions, memories, thoughts, emotions, etc. so it is on the record in writing. If there were other witnesses, have them independently record their own impressions, thoughts, etc. Include in this exercise any drawings, sketches, or diagrams. Make sure you date and sign your documentation.

Seja persistente e não contraditório. Volte ao local da cena e registe o mesmo local. Se foi bem sucedido uma vez, pode ser que nessa região ocorram avistamentos de UFOs/naves com regularidade, talvez por razões específicas desconhecidas, e talvez possa ser novamente bem sucedido. Pode também desejar voltar ao mesmo lugar a horas diferentes do dia (durante as horas de luz)para ter uma orientação e referência melhor. Filme apenas um ,inuto ou dois em circunstâncias “normais” para ter um termo de comparação. Escreva tudo o que viu imediatamente após o acontecimento. Logo após ter feito o registo da experiência/acontecimento, escreva imediatamente as impressões, memórias, pensamentos, emoções, etc para que fiquem registadas por escrito. Se houver outras testemunhas, peça-lhes para registar independentemente as suas próprias impressões, pensamentos, etc. Inclua quaisquer desenhos, esbolos, diagramas. Certifique-se que data e assina o seu documento/testemunho.

Always be prepared. Have a digital camera or better yet a video camera with you, charged and ready to go, at all times. Make sure you know how to use your camera (and your cell phone video/photo camera) quickly and properly. These events can occur suddenly, unexpectedly, and often quite randomly, so you will need to be prepared.

Esteja sempre preparado, Tenha sempre uma camera digital, melhor ainda, uma camera vídeo consigo, carregada e pronta a usar sempre que necessário. Certifique-se que sabe como lidar com a sua camera (ou com o seu celular/camera fotográfica) rápida e adequadamente. Esses acontecimentos podem acontecer súbita e inesperadamente e, por vezes, acidentalmente, por isso, necessita estar preparado.

Look up. Be prepared. Report. Share.

Olhe para cima, Esteja preparado, Relate, Partilhe.



Pf., clique no símbolo do YouTube e depois no quadrado pequeno, em baixo, ao lado direito para obter as legendas CC, e escolha PORTUGUÊS

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