Health Meaning

Desperate. bald should not try at home, but the researchers found that mice will regrow hair, not only the skin, after a flesh wound. The discovery precipitated the dogma that adult mammals can not produce new hair follicles, and suggests ways to improve skin grafts and reverse hair loss.

Steeped in the dermis of the skin, hair follicles packets dead cells together at its base and sends them to germinate as hair. Researchers have long believed that a mammal is born with a full set of follicles, leading to an irreversible decline in the dark with all lost or damaged. It was fifty years ago, researchers noticed regrowth of injured skin of mice, rabbits and humans, but the work "was somewhat ignored," says dermatologist George Cotsarelis survey of Pennsylvania School of Medicine of the University in Philadelphia .

recently, while studying how stem cells in the skin to help heal wounds, Cotsarelis and colleagues noticed the same phenomenon. Comb for an answer, the team removed skin patches mouse and let the injury heal naturally Hair sprouted in central healed patches of skin the team then scored bulges hair -.. the pocket of a follicle where stem cells reside - in healthy skin near the wound. Although the bulges have cells that moved and helped to close the wound, they make new follicles.

further experiments have shown that, rather than developing follicular cells strains, new follicles were from stem cells of the epidermis. "They have grown from cells that are not [normally] make hair follicles," Cotsarelis said. "They had to be reprogrammed" A key player in this reprogramming appears to be the Wnt protein, which plays many roles in the development and healing of wounds. More Wnt mouse occurs naturally, more hair grew And. the injured area should be important to stimulate hair growth, reports the team tomorrow in nature. Follica, a Cotsarelis co-founded company, is exploring how to apply the finding of reverse hair loss.

"Regenerate a new body from scratch is quite remarkable," said Bruce Morgan, a molecular geneticist at Harvard Medical School in Boston. He noted that the results can lead to better skin grafts; current grafting techniques do not allow the growth of follicles and glands necessary for the skin to maintain. He is not surprised that there seems to be a cross, with stem cells of the skin resulting in follicles, while the follicles are sending in cells to help close the wound. "When there is an injury, any worldwide locations "

related site

• An introduction to hair

A new study has found that a small molecule can trigger breast cancer cells to go on a rampage invasive. The molecule could be a potential target for new therapies.

Small pieces of RNA called microRNAs help control gene activity and orchestrate the development of plants and animals ( Science NOW, July 8, 02). But these essential molecules can also turn bad: Some of them apparently cause cancer. How they do it is poorly understood, although recent studies have suggested that many microRNAs come from regions of the human genome associated with cancer risk.

A team led by researcher Robert Weinberg cancer of the Whitehead Institute in Cambridge, Massachusetts, has undertaken to monitor the involvement of microRNAs in the spread, or metastasis, cells cancer of the breast. In a screen of 29 microRNAs previously implicated in breast cancer, the team identified one - called miR-10b - that was prevalent in a line of human breast cancer cells very aggressive, but not in sedentary tumor cells. When the researchers blocked the action of miR-10b, the invasiveness of these cells decreased by 10 times. And when scientists introduced miR-10b in a culture of non-metastatic breast cancer cells, they became very invasive, as measured by their ability to migrate through a filter in a layer of target cells.

The team then implanted miR -10B-making cells in the breast area of ​​young female mice. After 6 weeks, the cells began to spread to distant tissues such as the lungs; non-metastatic cells, however, have caused breast tumors but not spread. Finally, the researchers traced the genetic pathways that influence the regulation and action of miR-10b. They found that the production of the molecule is under the control of a gene called Twist , which had been previously identified as a "master regulator" of embryonic development. In turn, miR-10b influences the expression of two genes involved in cell migration and cancer formation. The scientists report their findings online September 26 in Nature .

Weinberg and colleagues warn that despite the importance of miR-10b in triggering the spread of breast cancer cells, it is unclear whether their findings will lead to new therapies. "Although it is likely, we can not yet conclude that targeting miR-10b will reverse metastasis," says lead author of the paper, Whitehead cancer researcher Li Ma. But other scientists are more optimistic. "The work was carried out impeccably," says developmental biologist and pioneer in research of microRNA Frank Slack of Yale University. "The therapeutic potential is huge ... and very interesting pursuit." Carlo Croce, a cancer geneticist at Ohio State University in Columbus, agrees that the results "are very important and can be a potentially important target for treatment."

related site

• learn more about breast cancer

workers of travertine plant near Denizli, Turkey, were recently surprised when they sawed a block limestone for tiles and discovered a portion of a human skull. Now it seems they involuntarily exposed fossilized remains of a species long sought the man who lived 500,000 years ago, researchers say. Although only four skull fragments were found, the fossil also shows the first case of tuberculosis.

The Middle East has long been an important crossroads for human travelers. "It is clear for some time that earlier hominids must have dispersed into Western Europe from Asia and / or Africa, and Turkey lies squarely on the likely route," says paleoanthropologist Philip Rightmire of Harvard University who was not part of the team. paleontologists spent decades prospecting in Turkey for remains of a human ancestor directly Homo erectus , which was the first hominid to migrate out of Africa. Although scientists have discovered fossils of H. erectus who lived there 1.7 million years in the area of ​​Georgia, they found some fossils of man in this region that are between 1.7 million and 0,000 years ago.

After the plant manager contacted a researcher at the local university level, he alerted the rest of the team, which included researchers in France, Germany and the United States. They report in the current issue of American Journal of Physical Anthropology find that most resembles H. erectus . However, Rightmire said it might also be a member of H. heidelbergensis , a species found in Europe, which is thought to be the direct ancestor of Neanderthals.

Whatever his identity, the lead author John Kappelman of the University of Texas, Austin, said the skull bears scars that are a "ringer" to those created by the bacteria leptomeningitis tuberculosa , which causes a form of tuberculosis (TB) that attacks the membranes of the brain. The scars are the first signs of the disease in humans, said Kappelman. Previously, the earliest evidence of tuberculosis came from Egyptian and Peruvian mummies were old of thousands of years.

The presence of TB may also provide clues about what it looked like early humans and how it adapted to new habitats. If the hominid had dark skin, for example, he could have trouble getting enough vitamin D because it migrated north, because people with dark skin absorb less sunlight needed to make vitamin D than do people with fair skin. And when humans have a vitamin D deficiency, their immune system may be less vigilant, perhaps involving migrants with dark skin in Africa more vulnerable to diseases such as tuberculosis while heading climates less sunny Kappelman said.

"This is an extremely important finding," says paleoanthropologist Clark Larsen of Ohio State University, Columbus, because infectious disease can reveal new challenges faced by early humans as they moved in temperate regions. Kappelman hope the rest of the skull will eventually be located. "There were bones in the other slab, we have not," he said. "Someone can find the lottery prize of H. erectus kept in their tile counter."

Related Sites

• More details on Homo erectus
• the history of TB

About $ 1 billion a year goes into malaria treatment and prevention, but money hitting the best targets? Today, researchers have published a detailed map of global malaria risk, and it shows that some countries risk receiving less investment per capita than others. Public health experts hope the new information will help them realign their efforts against malaria-eradication to better respond to the threat.

Malaria, a disease transmitted by mosquitoes caused by the parasite Plasmodium falciparum , infects some 500 million people each year and kills 1 million of them. Sub-Saharan Africa is by far the worst affected region, but complete data on a global scale are lacking. The latest map of malaria was established in 1968, and funding agencies today are left guessing where their dollars are needed most. In 06, the Wellcome Trust in the UK and institutions based on the world launched the Malaria Atlas Project (MAP) to map, model and predict the overall risk of malaria.

MAP researchers data on the incidence of malaria reported by countries and compiled research groups from 02 to 06, as well as climate data such as temperature and aridity that limit malaria transmission . The researchers then converted this information into regional and global maps showing where current malaria transmission risk is highest. The map estimates that 2.37 billion people - 35% of the world population - are at risk of contracting malaria. This decreases the earlier risk estimates by 46% and 48% in 1994 and 02 respectively. One billion people live in high-risk areas, and outside Africa infection rates were less than 5%, the group announced online today PLoS Medicine .

The map highlights some disparities between risk and finance, said epidemiologist Carlos Guerra of the University of Oxford, UK, who led the study. For example, at-risk populations in Southeast Asia and Africa receive less funding per capita than those living in low-risk areas such as the South American country of Suriname. Guerra welcomes the rapid progress in South America, but says that the current per capita funding is simply not enough to meet eradication goals and argued that the money should be reallocated to areas where malaria is a "huge problem."

The mapping results are not surprising, but are unprecedented in their accuracy, says malaria biologist Dyann Wirth of the Harvard School of Public Health in Boston, who was not involved in the project . The work signals a "maturation" in the field of malaria research and provides an important basis to determine the success of future malaria interventions, she said.

Related Sites

• The paper malaria Card
• Atlas malaria project
• WHO malaria

Francis Collins, the medical researcher perhaps best known for steering the Human Genome Project, is stepping down as director the National Human Genome Research American Institute (NHGRI) in Bethesda, Maryland. Collins said today that he will leave on August 1st to write a book and to explore other possibilities, which could include involvement in the presidential campaign or take a non-profit position.

Collins, 58, took the head of the National Institutes of NHGRI (NIH) of Health in 1993 as he was preparing to sequence the human genome, a controversial proposal of $ 3 billion. The heated quest when a private company, Celera, jumped, spurring fierce competition. Both public and private efforts published a draft in 01 and the full sequence was completed in 03. According to Collins, the institute has also advanced sequencing genomes of several model organisms, from yeast to the platypus, that stimulated the study of evolution at the molecular level. Collins defended the public sharing genome data and pushed legislation to protect people against discrimination based on their genes. A law codifying the protection was signed by President George W. Bush last week.

"It was a great era, when he was director," said Bruce Stillman, president of Cold Spring Harbor Laboratory in New York. One of the challenges of Collins, however, was to find new goals for the institute once the human genome was completed, Stillman says. He initiated projects as a major effort to develop knockout mice ( Science NOW, September 7, 06) and The Cancer Genome Atlas ( Science , 16 December 05, p. 1751), which, with the cancer institute, is sequencing of mutations in human cancers. Yet as sequencing becomes cheaper, the next director will redefine the scientific role of the institute, said Stillman.

Collins told reporters today that his time at the NIH was "wonderful," despite the recent NIH budget fall, who says he has "much more difficult." However, reasons for his departure has nothing to do with the management or NIH budget; he says he is simply the fact that "the time seems right" to explore employment opportunities with more freedom than if he was still in a federal position. Collins plans to work on a book on personalized medicine and said he would be interested in helping a presidential campaign if asked. another position of the Government is also possible, said Collins. for example, if he was approached to become the next director of the NIH, "I would be crazy to say no, "he said.

Alan Guttmacher, NHGRI now deputy director, will serve as acting director while the NIH Director Elias Zerhouni seeks a successor.

Related site

• Collins at NHGRI biography website

Scientists say they have demonstrated the viability of a new way of studying the disease using a patient's own cells. Yesterday, a team from the universities of Harvard and Columbia announced that they have generated a population of motor neurons - the nerve cells that control muscle movement - from the skin cells of a 82-year-old woman with amyotrophic lateral sclerosis (ALS). These cells provide a way to take ALS studies "in the patient and in the Petri dish," Harvard biologist Kevin Eggan said at a press conference.

For many diseases, the researchers would like to study the diseased cells of a patient in the laboratory; their ultimate hope is that they can also fix these cells by modifying genetically and then reinjected into the patient. Until recently, scientists believed that the way to do it would be through therapeutic cloning, a controversial technique - still unproven for humans - which comprises the nucleus of a body cell into an enucleated egg. The resulting cells can then be induced to differentiate into any type of body tissue.

The ethical problems of using eggs can be circumvented with induced pluripotent stem (iPS) cells, which are adult cells reprogrammed to act like embryonic stem cells. In 06, researchers have created these mouse cells and rat by introducing a combination of four genes of a culture of skin cells. Then last year, the scientists showed that they could do the same with human cells . The new study, published online today by Science shows that iPS cells can be generated successfully, even from the skin cells of an elderly sick person, says Eggan.

ALS involves the progressive degeneration of motor neurons in the spinal cord, causing paralysis of the limbs and breathing. The team, led by Eggan and Christopher Henderson of Columbia University Medical Center, rose iPS cells by introducing four genes used in previous studies in about 30,000 cells from the patient's skin. Among the hundreds of colonies that developed from these cells, scientists found that a handful had markers of pluripotency. For these lines of iPS cells added the scientific molecules known to guide pluripotent mammalian cells into nerve cells. A significant proportion of them showed characteristic markers of motor neurons. Other tests - such as injection of the cells into mice or chicken embryos to see if they establish appropriate connections -. Will be needed to see if they are neurons full

The woman had a familial form of ALS caused by a mutation in the gene called superoxide dismutase 1 , or SOD1 , which is responsible for only 2% of ALS cases. Eighty-five percent of ALS cases are "sporadic" - meaning that there is no known inherited mutation; many probably result from genetic changes that occur through life interacting with environmental influences. However, Eggan said, "I think this approach has incredible promise to study other forms of ALS." Symptoms of family and sporadic forms of ALS are so similar, he added, they probably share many common mechanisms.

"It is exciting that they have created human cells from the patient material," says Jeffrey Rothstein cell researcher stem from Johns Hopkins University in Baltimore, Maryland, who is also studying ALS. But he warned that the cells are useful in research, they should be exactly the same as those that cause the disease in the patient. "You do not want a partial replica of the motor neuron," says Rothstein. iPS-generated neurons, they say he, perhaps of little use in the reproduction of the fate of motor cells buffeted by a lifetime of exposure to the drug and other metabolic and environmental influences.

The second oldest specimen ever discovered HIV has postponed the date of the virus is passed from chimpanzees to humans more than 2 decades, according a new study. The study helps to clarify further how the AIDS epidemic began, and it reinforces the growing evidence that HIV does not spread easily to what cities have emerged in Central Africa.

The sample derived from a lymph node biopsy taken in 1960 from a 28 year-old woman in what is now Kinshasa, Democratic Republic of Congo. Researchers led by evolutionary biologist Michael Worobey of the University of Arizona, Tucson, blocks analyzed tissues from 27 patients between 1958 and 1960 as the University of Kinshasa had kept with some patient records. As noted Worobey, these patients had biopsies taken because they had mysterious ailments, including abnormalities of the lymph nodes, which are common in people with HIV. "You really could ask for a better cohort look for people who had HIV in Kinshasa," he said.

As the researchers describe in tomorrow's issue of Nature they isolated about 5% of the HIV genome lymph woman. A comparison with the oldest sample of HIV, also from Kinshasa and dates to 1959, found that they differed by about 12% in an overlap area. This led Worobey and his colleagues estimate that the two viruses had a common ancestor around 108, which means that HIV that triggered the current epidemic of AIDS rose from chimpanzees to humans before. The previous estimates dating the common ancestor about 1931.

Worobey and co-authors link the spread of HIV to the growth of Kinshasa and other cities in central Africa. They document that no city in the region had more than 10,000 inhabitants until 1910, supporting the longstanding theory that HIV needed this critical mass of people in urban areas to implement. "The virus is really struggling to ignite an epidemic" until authorized cities fast transmission, notes Worobey. He says this emphasizes that concerted prevention efforts today can stop local epidemics foothold.

Worobey, whose previous detailed studies on the spread of HIV from Africa to the United States and Europe, still hundreds of samples to analyze and is looking for more samples old. "People have not really tried to find these old samples," he said.

Beatrice Hahn, whose group at the University of Alabama, Birmingham, deduced previous estimates using modern samples HIV, applauds the hard work. "This was done just the way you want to do," said Hahn, who notes that a second lab has independently confirmed the sequence, which never happened with the sample 1959. "This looks to lean backwards to do it the right way."

Senator Chuck Grassley (R-IA) has landed another big name in its probe of financial conflicts of interest in science . Today New York Times reports on the investigation Grassley psychiatrist Frederick Goodwin, former director of the National Institute of Mental Health (NIMH), which hosts the radio show L infinity spirit . The show, which will air on National Public Radio stations, covered the effects of drugs on the brain. ( Slate was on the story in May.)

Grassley investigators unearthed evidence that Goodwin, who left NIMH in 1994, took at least $ 1.3 million of drug industry that has not been disclosed on the program. For example, in 05, he received $ 329,000 to give lectures to promote a mood stabilizer drug made by GlaxoSmithKline - and in September this year, told the audience that the stabilizing medications mood can help children with bipolar disorder. The producers of The Infinite Spirit recorded their latest episode in October, but the show continues in reruns. NPR told Times he drew The infinite spirit its satellite channels.

If academics working on dangerous pathogens must undergo periodic psychological assessments to ensure they are not mentally unbalanced as US army researcher Bruce Ivins seems to have had? At present, they are not. But the question was clearly on the table today at a meeting of the National Science Advisory Board on Biosecurity.

Over the past two years, the council has discussed that federal agencies, institutions and scientists need to do to prevent accidental or deliberate misuse of research in life sciences. In the wake of Ivins involvement in the 01 attacks the anthrax letters, NSABB now looking at ways to minimize the threat of a university scientist with access to deadly pathogens conducting a criminal or terrorist attack. While federal rules already require institutions and individuals who are researching some agents to submit to a security check, where Ivins, who committed suicide on July 29, has raised concerns about whether the procedures current are good enough.

The Board has not yet come with recommendations on the issue, but adding assessments of mental health screening process is a possibility. A member NSABB said Science as the Board may decide not to recommend new requirements at the end.

As Massachusetts General Hospital and the Senate of the United States to investigate allegations of conflict of interest, Harvard Medical School has appointed a committee to review its rules governing conflicts. Of The Boston Globe

US Senator Charles E. Grassley, an Iowa Republican, accused three Mass General psychiatrists do not fully disclose payments they received from. pharmaceutical companies for consulting and other activities. The doctors said they believed they were following the rules. Harvard Medical School and Mass. General conduct their own investigations.

"The public and regulators say we must be much more transparent about any faculty relations have with the industry," said Dr. Richard Schwartzstein, a member of the review committee and a pulmonologist at Beth Israel Deaconess. "The trend is increasingly strict, there is no question about it."