Anna+H.

=Wikipost #1: Genetics and Aging= For thousands of years, humans have looked for ways to extend their lives through exercise, healthy eating, and most recently, genetics. A study carried out by Kiel University discovered a genetic similarity between the long-living freshwater polyp Hydra and human beings. That similarity is the FoxO gene. FoxO is a gene that is responsible for stem-cell production, an important part of remaining youthful. Because the Hydra has an enhanced FoxO gene, it has significantly more stem cells. This is important in that stem cells will help repair parts of the body when they become damaged. In fact, FoxO has been found to be more active in centenarians than in the average human, which is part of why it is believed to play a significant role in aging, or lack thereof.

Slowing Aging
media type="youtube" key="V48M5j-6zdE" height="315" width="560" Here, Cynthia Kenyon, an American molecular biologist and biogerontologist explains how the FoxO gene can be used to double the lifespan of the worm Caenorhabditis elegans. I found this interesting because they actually managed to induce mutation in the worm so that the gene was far more active than it normally would be. This is a picture of the Caenorhabditis elegans, the worm which was given a “boost” of the FoxO gene, causing it to age twice as slowly as a worm of the same species without the boost. This is the freshwater polyp hydra, which is thought to be immortal since they do not show signs of aging. It is one of very few creatures with this ability, the quaking aspen, the deep sea oyster, as well as some types of tortoise. For this hydra in particular, its longevity is thought to be due to its hyperactive FoxO gene.

This is a mouse brain. I included this picture because only a few weeks ago, researchers at Yale University discovered a way to //reverse// aspects of the aging process in the brains of mice. They isolated a gene called Nogo Receptor 1, which is responsible for controlling the plasticity (or flexibility) of the adult mouse brain. They then blocked this gene, forcing the process to reverse, so that mice returned to their adolescent mental capabilities. This meant that they were better capable of overcoming brain damage and were more susceptible to learning. A human brain: the findings by Yale University on the brains of mice and the reversal of the aging process are significant because they may contribute to better methods of treatment for patients with issues such as Post-Traumatic Stress Disorder.

Primates and Their Teeth
media type="youtube" key="rDIBtP85F3c" height="315" width="420" This video contains a biological anthropologist from George Washington University and a material researcher from the National Institute of Standards and Technology, explaining briefly the evolution of the tooth and jaw structure for apes, chimpanzees, and orangutans. It also explains why their palletes are formed in these ways according to what they eat.

Agriculture and Dental Diseases
Scientists have been able to gather evidence scraped from the inside of ancient mouths to suggest that dietary changes throughout history have effected out dental health. They were actually able to ancient bacterial buildup trapped by tartar on the teeth of human skeletons ranging from 6000 to a couple of hundred years ago. The skull of a //Homo neanderthalensis//, compared with the profile of a //Homo sapien.//

It was discovered that based on the type of diets that humans favoured in different areas and at different times in history, they exposed their mouths to different types of bacteria. Our ancestors, without fancy toothbrushes and whitening toothpastes, actually may have had better teeth then we do! A direct comparison of the skull of a //Homo neanderthalensis// and a //Homo sapien//. As you can see, the face of the //Homo neanderthalensis// is longer, and protrudes more at the mouth and recedes at the chin. This is a direct result of the type of foods that sustained it, and their consistancy. With the invention of agriculture, humans began to learn to cook their food, resulting in a softer consistancy. This meant less chewing was necessary, and actually plays a large role in the introduction of the less-protrusive skull of the //Homo sapien// on the right.

When humans began to eat more wheat, gum disease-causing bacteria began to thrive. When humans began to consume processed flour/sugar (as during the Industrial Revolution period), tooth-decay causing bacteria (//Streptococcus mutans)// moved in. The //Streptococcus mutans// which causes tooth decay.

Every major dietary change in human history altered our "oral ecosystems." In today's world, we take in more sugar and starch then ever before in history, and our mouths are not equipped to deal with it. We have limited the variety of bacteria in our mouths, which actually causes us to be less resilient when confronted with disease-causing bacteria. In fact, our mouths are still stuck in the past, struggling to adapt and evolve.

[[image:http://upload.wikimedia.org/wikipedia/commons/b/b3/Craniums_of_Homo.svg width="567" height="414"]]
Humans throughout evolution: 1) gorilla; 2) Australopithecus; 3) //Homo erectus//; 4) //Homo neanderthalensis//; 5) Steinheim skull; 6) //Homo sapien//.

Building a Better Prosthetic
media type="youtube" key="MLvwTlbj1Y8" width="560" height="315" Here, Todd Kuiken talks about "bionics," a nickname for the fancy new prosthetics demonstrated in the video. As a physiatrist and an engineer, he is helping to build a prosthetic arm that will not only be connected to the nervous system (causing it to move almost as seemlessly as a real arm), but that will also be able to feel sensations, such as different textures and hot and cold. Above is patient Amanda Kitt with her bionic arm. This type of advanced bionics would be done by providing the arm with a computer which is connected to the nerves left over after an amputation. This links the brain impulses to the computer, and causes it to move. This technology is called targetted muscle reinnervation. Above is a picture describing the different nerves in the arm. One of the many problems that scientists are facing in attempting to build the realistic prosthetic is that the material on the surface of the prosthetic would need to send and receive //thousands// of signals per second in order for it to truly mimic the behaviour and uses of a real limb.

Phantom Limbs and Rats With Prosthetics
One thing that has seemed to prove useful in this hunt for a better prosthetic is a strange phenomenon referred to as "Phantom Limb Syndrome." Basically, Phantom Limb Syndrome means that a person who has lost a limb or become paralysed still feel as though the missing limb were there, even though the nerves have been severed. This can prove to be uncomfortable, and even painful for those suffering from it. However, it has been good news for researchers: Phantom Limb Syndrome suggests that the severed nerves are still very much alive.

The New Bionic Hand
Scientists seem to have found one possible solution through experiments on rats. It has been found that when prosthetic legs (made containing biocompatible fibres to mimic nerves) are placed on the nerve endings of the rats' severed limbs, the rats' nerve fibres left over from the amputation begin to grow and fuse back together. Only this past winter the first bionic hand that can "feel" was presented and is due to be attached to a man's arm sometime this year. How it works is that the hand will be attached to the man's nervous system using two electrodes, hooked up to two of the main nerves in the arm, the ulnar and median nerves. The idea is that the hand should allow the patient, at the very least, to feel pressure. This bionic hand, if it works, will be a huge leap for prosthetics.

Altruism in Animals and Twins
Above, an image of a cat nursing her own kittens as well as an abandoned puppy...not an uncommon occurrence of compassion in nature. Studies of identical twins have also contributed to the belief that compassion may be (at least in part) hereditary, with at least 40-50% of a ltruistic behaviour being inheritable. Biologists believe that compassion in humans first happened because of a principle known as "kin selection." This means that when an animal acts in an altruistic way towards members of its own family, it is helping its own genes to continue and be passed on by helping the animal not to die. This leads biologists to conclude that the roots of compassion are actually self-serving.

Vampire Bats and Altruism
A prime example of altruism in animals comes from the most unlikely of sources: above is a picture of a little critter called a // Desmodus rotundus, //more commonly known as a South American vampire bat. These little guys are actually known to regurgitate blood into the mouths of other members of their family who did not eat that day.

Fitness and Altruism
This all relates back to Charles Darwin's theory of the "Survival of the Fittest" in that natural selection has allowed the trait of compassion to continue because it actually benefits humanity, as well as other species. This theory was expanded upon by British scientist William Hamilton, in his idea of "inclusive fitness." He realized that animals, including humans, were likely to behave in altruistic ways if the benefit of the altruism was greater than the cost to the individual. This theory meant that the definition of fitness also included the fitness of one's relatives. Another benefit to altruism, as Hamilton discovered, was the fact that if you did something nice for someone, they were likely to do something nice for you in return (too bad this isn't set in stone). In conclusion, altruism actually helps a species to survive, thereby furthering the gene pool and reinforcing Darwin's theory of evolution!

Further Reading/Info
[|More on vampire bats and altruism] [|A short article on evolutionary biologist William Hamilton in the New York Times.] [|A short (and really cool) video on the biological reasoning behind altruism.] [|An article on kin selection.]

What Causes Infertility?
There are a number of reasons for why a couple may be infertile: in a male, infertility could be caused by things such as sperm disorders (immature, abnormally shaped, or "lazy" sperm); chromosomal abnormalities (men with an extra X chromosome don't produce sperm or only produce it in very low quantities); testicular trauma, or exposure to toxic hazards or substances. There are also a number of factors that could contribute to infertility in women: failure to produce mature eggs (ovaries do not create follicles that are normal in which the eggs can mature); defect of the hypothalamus (the hypothalamus may not send the proper signals to the pituitary gland, causing the hormonal stimuli to fail to send FSH and LH, which are vital to the maturation of eggs); scarred ovaries, premature menopause, infection, and ectopic pregnancy can all contribute to or cause infertility.

Modern Baby-Making
There are a number of ways to either solve problems causing infertility or otherwise create a baby. These methods may include in vitro fertilization, which is pictured above. In vitro fertilization is performed when sperm and eggs are combined outside of the body in a laboratory. After the combined sperm and egg begin to form an embryo/embryos, it/they are placed back into the womb of the mother. Other options for infertile couples may include artificial insemination (pictured above), use of a surrogate, fertility drugs/other treatments, and surgery. These are some of the most commonly used methods of reproduction when the "old fashioned way" just isn't cutting it. Of course, the method used depends upon the fertility issue at hand: for example, artificial insemination would be more likely to be used if there is an issue with the fallopian tubes, or if ovulation failed to occur in the female. Fertility drugs are most likely to be used if the female ovulates rarely or irregularly.

Further Reading/Info
[|A website about fertility drugs for women.] [|A video about the future of reproduction.] [|Conditions causing female infertility explained.] [|Some fast facts on infertility.]