Paraphyletic

Medicine and human biology
. Foot fungi a thriving, diverse community More than 80 different types of fungi make human feet home, researchers report May 22 in Nature. The tiny organisms stake claims all over a person’s skin, but only the feet carry such a diverse group of settlers, says study coauthor Julie Segre, a geneticist at the National Human Genome Research Institute in Bethesda, Md. The study is the first census of skin-dwelling fungi. By helping to identify differences between healthy and unhealthy fungi, it could one day lead to targeted treatments for athlete’s foot or toenail infections. — Meghan Rosen, Science News More here

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Foot fungi a thriving, diverse community

More than 80 different types of fungi make human feet home, researchers report May 22 in Nature. The tiny organisms stake claims all over a person’s skin, but only the feet carry such a diverse group of settlers, says study coauthor Julie Segre, a geneticist at the National Human Genome Research Institute in Bethesda, Md.

The study is the first census of skin-dwelling fungi. By helping to identify differences between healthy and unhealthy fungi, it could one day lead to targeted treatments for athlete’s foot or toenail infections.

— Meghan Rosen, Science News

More here

Reo Kometani and Shinji Matsui A new study of epithelial mucus in a wide variety of animals shows bacteriophages — viruses that attack bacteria — are far more prevalent (relative to their bacterial prey) when there’s more mucus around. The authors from San Diego State, UC San Diego, and Rainbow Rock (whatever that is) suggest mucus membranes may have evolved, in part, to provide a friendly incubator for bacteria-killing viruses. If they’re right, that means there’s a new dynamic to consider when pondering the thickness of mucus membranes. Too much mucus can impede the exchange of oxygen, or the absorption of nutrients. Too little mucus could mean an ulcer, or now, we learn, too little space for helpful viruses to live in.

Reo Kometani and Shinji Matsui

A new study of epithelial mucus in a wide variety of animals shows bacteriophages — viruses that attack bacteria — are far more prevalent (relative to their bacterial prey) when there’s more mucus around.

The authors from San Diego State, UC San Diego, and Rainbow Rock (whatever that is) suggest mucus membranes may have evolved, in part, to provide a friendly incubator for bacteria-killing viruses.

If they’re right, that means there’s a new dynamic to consider when pondering the thickness of mucus membranes. Too much mucus can impede the exchange of oxygen, or the absorption of nutrients. Too little mucus could mean an ulcer, or now, we learn, too little space for helpful viruses to live in.

thebrainscoop: Rebloggable by request. Stereotypic Movements in Zoo Animals Stress and Adaptation. Toward Ecologically Relevant Animal Models As unsatisfying as this may be, the answer is actually “we don’t know.” Noting that non-human animals behave differently and even predictably under stress, or that physiological changes apparently caused by social starvation are not enough to conclude non-human animals experience “mental illness” — that is a human-defined concept, defined by human experiences and human behavior. The risk of anthropomorphizing non-human animal behaviors here is great, particularly when the comparisons we draw between humans and other animals are made coarsely, e.g. concluding other animals experience mental illness because their brains overproduce the same neurotransmitter receptors we see overproduced in, say, clinically depressed (human) patients. Not only is human psychology tricky in that it is “somewhat subjective based off of interpretations by the patient,” but psychology itself can be subjective, for example, its categorization of mental illnesses, which seem to change every decade or so. Any organism that has a brain can have a brain that works poorly, or that initiates behaviors that are unhelpful to the organism’s health, survival, and reproduction. But science has not yet shown us is whether (a) there is a proper distinction to be made between a brain that is broken and a brain that is ill, and (b) the experience of mental illness in non-human animals, if it exists, is equivalent on some level to the experience of mental illness in humans. I think psychologists are doing the best they can, given dogs can’t tell the researchers how they’re feeling (or how the dogs are feeling, for that matter), but the fact is, the field is not far enough along to be answering big questions like this. Hard work and patience are yet required.

thebrainscoop:

Rebloggable by request.

Stereotypic Movements in Zoo Animals

Stress and Adaptation. Toward Ecologically Relevant Animal Models

As unsatisfying as this may be, the answer is actually “we don’t know.”

Noting that non-human animals behave differently and even predictably under stress, or that physiological changes apparently caused by social starvation are not enough to conclude non-human animals experience “mental illness” — that is a human-defined concept, defined by human experiences and human behavior. The risk of anthropomorphizing non-human animal behaviors here is great, particularly when the comparisons we draw between humans and other animals are made coarsely, e.g. concluding other animals experience mental illness because their brains overproduce the same neurotransmitter receptors we see overproduced in, say, clinically depressed (human) patients.

Not only is human psychology tricky in that it is “somewhat subjective based off of interpretations by the patient,” but psychology itself can be subjective, for example, its categorization of mental illnesses, which seem to change every decade or so.

Any organism that has a brain can have a brain that works poorly, or that initiates behaviors that are unhelpful to the organism’s health, survival, and reproduction. But science has not yet shown us is whether (a) there is a proper distinction to be made between a brain that is broken and a brain that is ill, and (b) the experience of mental illness in non-human animals, if it exists, is equivalent on some level to the experience of mental illness in humans.

I think psychologists are doing the best they can, given dogs can’t tell the researchers how they’re feeling (or how the dogs are feeling, for that matter), but the fact is, the field is not far enough along to be answering big questions like this. Hard work and patience are yet required.

Bill Murray sniffing a Baby Ruth in Caddyshack Nancy Shute, writing for NPR.org: Everybody In The Pool! But Please Leave The Poop Behind Perhaps you’ve noticed a toddler’s sagging swim diaper and wondered if it’s really keeping the poop out of your neighborhood pool. The Centers for Disease Control and Prevention has the answer for you: no. Last summer, researchers at the federal public health agency collected 161 filter samples from public swimming pools in the Atlanta area. More than half of those samples, 58 percent, were contaminated with E. coli. More here

Bill Murray sniffing a Baby Ruth in Caddyshack

Nancy Shute, writing for NPR.org:

Everybody In The Pool! But Please Leave The Poop Behind

Perhaps you’ve noticed a toddler’s sagging swim diaper and wondered if it’s really keeping the poop out of your neighborhood pool.

The Centers for Disease Control and Prevention has the answer for you: no.

Last summer, researchers at the federal public health agency collected 161 filter samples from public swimming pools in the Atlanta area. More than half of those samples, 58 percent, were contaminated with E. coli.

More here

biomedicalephemera:

Top: Uterine lining at 5 1/2 months, displaying thin maternal separation from fetus, and high level of placental implantation
Center: Relation of placenta to uterus at 5 weeks and 8.5 months
Bottom: Major arteries and veins of the placenta

Did you know that the placenta is a temporary organ that’s actually created by the fetus, and not the woman?

The human female is a curious creature; like our close great ape cousins, but unlike almost all other mammals, they build up a thick barrier in the uterine wall, to protect against any potential embryo that might implant itself. When there’s no embryo implantation, the thickened wall is shed, in the process known as menstruation.

The thing is, most mammals don’t menstruate. They go into heat, and occasionally shed uterine lining (if the uterus is scratched, or an egg tries to implant but fails, for example), but there’s no regular cycle of bloody discharge relating to breeding. This is because other mammals go through triggered decidualization (developing a uterine lining only when a fertilized egg begins to implant itself), while the great apes (and a couple other convergently evolved families, including bats) experience spontaneous decidualization, where they develop a thick uterine lining during every ovulation, before an egg can even attempt to implant itself.

Why the different linings? Well, it turns out that there are three types of mammal placentas (remember, placentas are developed by the embryo/fetus, not the mother):

  1. Epitheliochordal, which is completely superficial, and does not connect in any significant way to the mother’s body. The endometrial epithelium, connective tissue, and uterine epithelium are all preserved and undisturbed in the mother. The fetus is separated from the mother by three layers of tissue. Nutrients and waste are delivered and eliminated through diffusion, rather than direct connection. This group includes equids, swine, and ruminants.
  2. Endotheliochordal, which is slightly more invasive to the mother, only preserves the uterine epithelium. Nutrients and waste are not exchanged through direct connection to the mother, but the placenta only leaves one layer of tissue between it and the mother. This group includes cats and dogs.
  3. Hemochorial is the most invasive form of placenta in the animal kingdom. The embryo directly hooks itself up to the host (mother’s) blood flow, and leaves no tissue layers between the female and the placenta. This allows much more efficient nutrient transfer to the embryo or fetus, but is also potentially the most harmful to the female since the embryo attaches itself so securely to the uterine wall. The female must develop preemptive measures (a thickened uterine lining) to protect herself from a life-form that is literally driven to take all of the nutrients it needs to develop, and which has adapted to connect itself directly to the host. This group includes elephant shrews, most bats, and most primates.

Interested in more about the science behind reproduction and how amazingly efficient the human embryo is at sucking its host clean, just to obtain its needed resources for development?

PZ Meyers at Pharyngula has an understandable explanation of the article I referenced for this post.

There is also a great site by R. Bowen about the pathophysiology of the reproductive system.

An American Text-Book of Obstetrics for Practitioners and Students. Edited by Richard C. Norris, 1895.

Image by Matthew Landry From the completely random but awesome department, my very-service-oriented hospital now has two researchers who will have experiments aboard the International Space Station. The first researcher, @proteinwrangler, is an old pro, investigating crystal formation in microgravity. Space researcher #2 is Alessandro Grattoni, who will be looking at how nanoparticles (actually microparticles) behave so that they can design better drug delivery devices. Why this is happening in space is a little complicated. You can’t see nanoparticles, so following their movement (without interfering with their natural movement) is currently impossible. Microparticles can be seen, but are affected by gravity. So the experiment will actually be looking at microparticles, not nanoparticles, but Alessandro believes a model based on the behavior of microparticles will approximate one based on the behavior of much smaller particles (in gravity). More here.

Image by Matthew Landry

From the completely random but awesome department, my very-service-oriented hospital now has two researchers who will have experiments aboard the International Space Station. The first researcher, @proteinwrangler, is an old pro, investigating crystal formation in microgravity. Space researcher #2 is Alessandro Grattoni, who will be looking at how nanoparticles (actually microparticles) behave so that they can design better drug delivery devices.

Why this is happening in space is a little complicated. You can’t see nanoparticles, so following their movement (without interfering with their natural movement) is currently impossible. Microparticles can be seen, but are affected by gravity. So the experiment will actually be looking at microparticles, not nanoparticles, but Alessandro believes a model based on the behavior of microparticles will approximate one based on the behavior of much smaller particles (in gravity).

More here.

Macular degeneration is a disease of the middle of the retina. It can be caused by genetics, aging, or both. In the image, “dry” macular degeneration is evidenced by yellow mottling, “wet” by the red splotches (photo by Eric Kepler) The National Eye Institute has altered its nutritional supplement recommendations for people at risk for developing age-related macular degeneration (AMD). A retina specialist at The Methodist Hospital who was involved in the large-scale, multi-institutional study said omega-3 fatty acids seem to have no positive effect on the development of AMD, but that beta-carotene should be replaced by a combination of two other carotenoids — zeaxanthin and lutein. The reason? Zeaxanthin and lutein seemed to be just as good at reducing AMD risk, and Increased beta-carotene consumption seems to be associated with greater risk for lung cancer. They don’t know why beta-carotene is associated with lung cancer risk, though, so take that for what it’s worth. More here.

Macular degeneration is a disease of the middle of the retina. It can be caused by genetics, aging, or both. In the image, “dry” macular degeneration is evidenced by yellow mottling, “wet” by the red splotches (photo by Eric Kepler)

The National Eye Institute has altered its nutritional supplement recommendations for people at risk for developing age-related macular degeneration (AMD).

A retina specialist at The Methodist Hospital who was involved in the large-scale, multi-institutional study said omega-3 fatty acids seem to have no positive effect on the development of AMD, but that beta-carotene should be replaced by a combination of two other carotenoids — zeaxanthin and lutein. The reason? Zeaxanthin and lutein seemed to be just as good at reducing AMD risk, and Increased beta-carotene consumption seems to be associated with greater risk for lung cancer. They don’t know why beta-carotene is associated with lung cancer risk, though, so take that for what it’s worth.

More here.

Disturbing. Update: Holdren Attacks House Bill, Defends NSF’s Grant Selection Process A congressional proposal to alter how the National Science Foundation (NSF) chooses research projects “would throw the basic research baby out with the bath water,” says presidential science adviser John Holdren. Speaking this morning at the annual Science and Technology Forum sponsored by AAAS (which publishes ScienceInsider), Holdren sharply criticized legislation drafted by Representative Lamar Smith (R-TX), chair of the Science, Space, and Technology Committee of the U.S. House of Representatives. Smith’s bill would require NSF to promise that any research it funds “advance[s]” national health, prosperity, and security, “is ground breaking,” and is not being supported by another federal agency. In a statement released 30 April, Smith said the bill “improves” on NSF’s current process of peer review “by adding a layer of accountability” intended to “ensure that taxpayer dollars are spent on the highest-quality research.” More here from ScienceInsider.

Disturbing.

Update: Holdren Attacks House Bill, Defends NSF’s Grant Selection Process

A congressional proposal to alter how the National Science Foundation (NSF) chooses research projects “would throw the basic research baby out with the bath water,” says presidential science adviser John Holdren.

Speaking this morning at the annual Science and Technology Forum sponsored by AAAS (which publishes ScienceInsider), Holdren sharply criticized legislation drafted by Representative Lamar Smith (R-TX), chair of the Science, Space, and Technology Committee of the U.S. House of Representatives. Smith’s bill would require NSF to promise that any research it funds “advance[s]” national health, prosperity, and security, “is ground breaking,” and is not being supported by another federal agency. In a statement released 30 April, Smith said the bill “improves” on NSF’s current process of peer review “by adding a layer of accountability” intended to “ensure that taxpayer dollars are spent on the highest-quality research.”

More here from ScienceInsider.

medicalschool: Lungs Volume Rendering of an ECG gated I.V. contrast enhanced thoracic CT angiography. Pictured above is the lung. The lung shows several small emphysematous bullae.

medicalschool:

Lungs

Volume Rendering of an ECG gated I.V. contrast enhanced thoracic CT angiography. Pictured above is the lung. The lung shows several small emphysematous bullae.

(Source: farm9.staticflickr.com)