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Minggu, 01 Juli 2012

Revisiting Scott's Polar Trek Towards Starvation

Revisiting Scott's Polar Trek Towards Starvation

Main Category: Nutrition / Diet
Also Included In: Sports Medicine / Fitness
Article Date: 01 Jul 2012 - 0:00 PDT

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On the centenary of Scott's ill-fated Terra Nova expedition to the South Pole, a study to be presented at the Society for Experimental Biology meeting on Sunday 1st July has shown that Scott's men starved to death because they were consuming far too few calories to fuel their daily exertion.

The researchers, environmental physiologist Dr Lewis Halsey of the University of Roehampton and polar explorer and physician Dr Mike Stroud, examined the voyage in light of today's knowledge of nutrition and how our bodies respond to extreme exercise, cold, and high altitude. They determined that their rations, which consisted of biscuits, pemmican, butter, sugar, chocolate, cereals and raisins, and were supplemented by pony meat at the start of the expedition, were inadequate.

Dr Lewis Halsey said, "There has been much speculation about what Scott died of. Almost certainly his death was due to chronic and extreme emaciation."

While consuming around 4,400 kcal/day, the men probably burnt nearly 7,000 kcal/day hauling their supplies on sledges across the ice and snow (based on data from Stroud's Antarctic crossing). For comparison, elite cyclists covering 4,900 km over 6 days use around 6,500 kcal/day. So Scott and his men were exhibiting daily activity levels considerably higher than most Olympic athletes in full training, but without consuming the enormous amount of food required to fuel such exertion.

In addition to the calorie deficit, the rations were too high in protein and low in fat to be optimal. Rations with more fat provide more energy for the same weight, which is a critical consideration when supplies must be carried. Although Scott made his rations more fat-rich than other polar rations had been, with 24% fat and 29% protein, today's adventurers eat up to 57% fat with 8% protein.

According to the study, other factors also worked against Scott's team. For instance, vitamins were not yet known about and there was some confusion at the time about which foods would prevent scurvy. While it is not clear whether the men developed scurvy, they probably did not consume enough vitamin C. On the other hand, the team did have a form of cocaine on hand, to help them keep going when they had run out of food.

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Sabtu, 30 Juni 2012

Type 1 Diabetes Prevented In Animal Study

Type 1 Diabetes Prevented In Animal Study

Editor's Choice
Academic Journal
Main Category: Diabetes
Also Included In: Immune System / Vaccines
Article Date: 30 Jun 2012 - 15:00 PDT

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Researchers from the Karolinska Institute, Sweden, managed to prevent Type 1 Diabetes onset in genetically susceptible mice, according to an article published in Diabetes. The scientists explain that they injected the mice with specifically prepared cells, which stopped their immune systems from destroying the pancreatic beta cells - cells that produce insulin - just in time.

Type 1 diabetes occurs when the body's immune system attacks and destroys the insulin-producing beta cells as if they were harmful pathogens - the immune system confuses them for alien bodies that cause harm. As beta cells become destroyed, insulin production goes down. Eventually, the patient has to inject insulin.

Experts are not sure what causes the immune system to attack the beta cells.

Beta cells are located in the so-called islets of Langerhans (islets), in the pancreas - they make up 65% to 80% of the cells in the islets. A healthy pancreas has about 1 million islets distributed throughout it. The islets produce and secrete at least 5 different types of hormones into the bloodstream: alpha cells produce glucagon, beta cells produce insulin and amylin, delta cells produce somatostatin, PP cells produce pancreatic polypeptide, and epsilon cells produce ghrelin.

Light microscopy - a mouse pancreatic islet. The beta cells are in green (insulin staining), glucagon in red, and t he nuclei in blue

Scientists do know, however, that certain immune cells, macrophages, are highly active and play a major role in beta cell destruction in Type 1 diabetes. On the other hand, macrophages can do the opposite - studies have shown that they can protect against inflammation-mediated tissue damage.

Immune cells communicate with each other by using cytokines - signal molecules. They tell each other what to do.

Robert Harris and team set out to find out which cytokines were involved in instructing the macrophages to become protectors, rather than destroyers.

Robert Harris said:

"We managed to achieve this aim, defining a novel combination of cytokines that confer on macrophages the ability to protect mice from developing Type 1 diabetes.
It has never previously been reported, that such an adoptive transfer cell therapy can be used in Type 1 diabetes and this study could thus represent a major advance towards disease prevention"

The scientists used non-obese diabetic (NOD) mice - these animals are generally susceptible to becoming Type 1 diabetics within 12 to 30 weeks after birth. The authors grew macrophages from bone marrow progenitors within the mice. They then stimulated the mature macrophage with a specific set of cytokines.

At the age of 16 weeks, the mice were separated into three groups:

The cytokine-treated macrophage group. The mice received macrophage treated with a specific set of cytokines.

The untreated macrophage group. The mice received macrophages which had not been treated.

The untreated group. The mice received nothing.

They then observed the mice for another twelve weeks. They were able to visualize the extent of immune-mediated attack of the beta cells in each treatment group, using a specific three-dimensional imaging technique that scientists at Umea University, also in Sweden, had developed.

Only 25% of the mice who received the cytokine-treated macrophages developed Type 1 diabetes, compared to 83% in the other groups.

Dr. Harris said:

"The cell therapy was initiated just 2 weeks before mice developed clinical diabetes. At this stage few insulin-producing beta cells remain in the pancreas, yet we were able to protect these so that the mice never developed diabetes.
Such a successful late-stage intervention has never previously been reported and is a significant result of our study. At the time of their clinical Type 1 diabetes diagnosis, most human individuals have already lost most of their insulin-producing beta cells."

Written by Christian Nordqvist

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HIV - Bacterial Vaginosis Linked To Greater Female-to

HIV - Bacterial Vaginosis Linked To Greater Female-to

Editor's Choice
Academic Journal
Main Category: HIV / AIDS
Also Included In: Women's Health / Gynecology
Article Date: 30 Jun 2012 - 16:00 PDT

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Women with bacterial vaginosis are much more likely to transmit HIV to males than other females, researchers from the University of California, San Francisco, reported in PLoS Medicine. The risk is three times greater, the authors added.

Bacterial vaginosis (BV), also known as vaginal bacteriosis, is a condition in which the vagina's normal balance of naturally occurring microorganisms in the vaginal flora has changed, so that the 'good' bacteria are reduced and the harmful bacteria increase. About 50% of all females with bacterial vaginosis are asymptomatic - they have no symptoms.

If BV symptoms do appear, they may include a watery and thin vaginal discharge, the discharge can become gray or white, and it may have a strong (fishy) smell. Less commonly, some women may experience a durning sensation when urinating, and itching around the outside of the vagina.

Bacterial vaginosis raises the risk of acquiring STIs

Women with bacterial vaginosis are more susceptible to acquiring sexually transmitted infections (STIs), including HIV and have a higher risk of preterm delivery. HIV-positive women with bacterial vaginosis potentially have higher HIV levels, and their cervix and vagina may shed greater amounts of the virus.

Lead author, Craig R. Cohen, MD, MPH, professor of obstetrics, gynecology and reproductive sciences at UCSF wrote:

"Previous research has shown that bacterial vaginosis can increase a women's risk of becoming infected with HIV as much as sixty percent. Our study is the first to show that the risk of transmitting HIV is also elevated.
Our findings point to the need for additional research to improve the diagnosis and treatment of bacterial vaginosis, which is extremely common in sub-Saharan Africa, the region of the globe with the highest burden of HIV."

They examined the link between bacterial vaginosis and female-to-male HIV transmission risk. The prospective study involved 2,236 HIV- positive women and their uninfected male partners from seven African countries.

After the scientists had adjusted the findings for variables, such as sexual behavior, socio-demographic factors, male circumcision, sexually transmitted infections, pregnancy and HIV levels in the HIV-positive women's blood, they discovered that bacterial vaginosis was linked to a considerably higher risk of female-to-male HIV transmission.

Cohen explained:

"We looked at the increased shedding of HIV in the genital tract, but that was not sufficient to explain the increased risk of female-to-male HIV transmission. It is also possible that bacterial vaginosis causes inflammation and that could be a factor. We don't really understand the relationship between vaginal flora and inflammation.
We think it's likely that the sharing of genital tract microbiota between women and men may be implicated as a cause of the transmission risk. The interrelationship of the sharing of flora remains poorly understood and is an important avenue for future research."

Cohen concluded that more studies are required to gain a better understanding of the vaginal flora's role. However, developing more treatments for bacterial vaginosis, such as improved drugs and probiotics would be a considerable step forward towards improving women's health in general, but it would also be beneficial in helping to decrease the number of HIV infections and the risk of transmission.

Written by Petra Rattue
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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Man Who Chewed Another Man's Face Had Only Marijuana

Man Who Chewed Another Man's Face Had Only Marijuana

Editor's Choice
Academic Journal
Main Category: Alcohol / Addiction / Illegal Drugs
Also Included In: Psychology / Psychiatry;Â Â Mental Health
Article Date: 30 Jun 2012 - 12:00 PDT

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Rudy Eugene, who in May 26th, 2012, attacked a man and chewed much of his face, did not have "bath salts" in his system but only marijuana, according to toxicology reports. Eugene was shot and killed while he assaulted Ronald Poppo. He had stripped himself nude, beaten up Poppo until he was unconscious, taken the man's pants off, and chewed off 75% of his face, including one eye, according to police.

Rudy Eugene was dubbed the Miami cannibal attack man, the Miami Zombie, as well as the Causeway Cannibal.

According to toxicology reports announced by the County Dade Medical Examiner yesterday, only marijuana was detected in Eugene's system, and no other street drug, prescription medication or alcohol. The Medical Examiner added that he also tested negative for adulterants which are often mixed in with street drugs.

"The department has also sought the assistance of an outside forensic toxicology reference laboratory, which has confirmed the absence of 'bath salts,' synthetic marijuana and LSD."

The police had initially speculated that he had gone crazy after consuming "bath salts".

Despite talking to Eugene's friends and family, nobody really knows what motivated the man to attack somebody else in that way. Reports say the two men knew each other. Eugene worked in a car wash, used to be a high school football player, and has a record of petty crimes that started at 16 years of age. Poppo, 65, was a homeless man whose family had presumed him dead.

The Drug Enforcement Administration (DEA) last year warned about the growing use of synthetic stimulants sold under the guise of bath salts or plant food. According to the DEA, these products, which have been sold over the internet, mimic the effects of LSD, cocaine or methamphetamine. New York State banned some bath salts last year, informing that there had been "hundreds of hospitalizations" linked to their use throughout the country. Doctors warn that they can cause hallucinations, high blood pressure (hypertension), paranoia, suicidal behavior, violent behavior, chest pains, and delusions.

Bath salts are sold under various names, including Vanilla Sky, Red Dove, White Lightening, Zoon, Tranquility and Snow Leopard.

What happened on May 26th, 2012?

5.30am - Eugene left his girlfriend's home in Fort Lauderdale and drove to Miami beach. His intention was to be at a concert.

His car stopped working. Security video showed him spending between 30 to 40 minutes in and around his Chevrolet Caprice.

According to witness reports, he left his car around midday and started crossing the MacArthur Causeway, a three-mile stretch. He took his clothes off.

Miami Beach police eventually had his car towed away. They found five empty water bottles and a Koran in the car. Police think Eugene had recently consumed the water in the bottles.

When Eugene reached the "crime scene", he was completely naked, and without shoes on. He got rid of his Bible at the crime scene.

1.55pm - Eugene came across Poppo who had been lying down under the elevated Metromover railway. Eugene started punching Poppo, took his pants off, and bit his face.

A cyclist saw Eugene attacking Poppo and called 911.

Jose Ramirez, from the Miami Police Department, arrived at the scene. He warned Eugene, telling him to stop attacking Poppo. Eugene did not heed Ramirez' warnings. Reports say Eugene growled at the police officer, and continued biting Poppo.

2.13pm - Ramirez shot Eugene once, and then again four times after the first shot appeared to have no effect.

The crime scene was near the The Miami Herald building - the incident was captured on one of the building's security cameras. According to the video, Poppo sustained an attack for 18 minutes before help arrived.

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