Stem Cells Could Boost Blood Transfusion Supplies

Scientists say they've found an efficient way to make red blood cells from human embryonic stem cells, a possible step toward making transfusion supplies in the laboratory.

The promise of a virtually limitless supply is tantalizing because of blood donor shortages and disappointments in creating blood substitutes.

Red blood cells are a key component of blood because they carry oxygen throughout the body.

Experts called the new work an advance, but cautioned that major questions had yet to be answered.

The research, published online Tuesday by the journal Blood, was reported by scientists at Advanced Cell Technology in Worcester, Mass., the University of Illinois at Chicago and the Mayo Clinic in Rochester, Minn.

The researchers said the cells they made behaved like natural red blood cells in lab tests, and that their process could be used in large-scale production. The results suggest that embryonic stem cells could someday supply type O-negative "universal donor" red cells for transfusion, they wrote.

Mohandas Narla, director of the Lindsley F. Kimball Research Institute at the New York Blood Center, called the results "a very good start."

Now it will be important to show that the complex lab process really can pump out red cells on a large scale, and that the cells will survive long enough in the human body to be useful, he said. Natural red cells circulate for an average of 120 days.

source: discovery channel

Scabies: Itchy global scourge is often misdiagnosed

Most people expect to return from vacation with fond memories of a relaxing or exciting time and perhaps photos to document it. That wasn't exactly the case for one 25-year-old man who took a trip to a Brazilian beach. Five weeks after returning to his home in Spain, he began to itch. He itched everywhere, intensely, and especially at night, which made sleep almost impossible.

After two months of this torment, with pimples and the sores from scratching them on his abdomen, buttocks and genitals, he sought help from a dermatologist. The diagnosis was scabies, an infestation of tiny mites he had most likely contracted from a sexual encounter during his vacation.

In describing this case in the July issue of the Cleveland Clinic Journal of Medicine, Dr. Sergio Vañó-Galván and Dr. Paula Moreno-Martin of Madrid called medical attention to a worldwide public health problem that each year affects more than 300 million people.

Scabies is frequently misdiagnosed and mistreated, partly because most physicians are unfamiliar with it and partly because its symptoms mimic so many other skin diseases.

A correct diagnosis is further complicated by the fact that symptoms can often appear six to eight weeks after a person becomes infested with the microscopic arthropod, making it seem as if the problem came from nowhere. But unlike other skin diseases, scabies is usually accompanied by a tell-tale sign: one or more burrows in the skin where female mites lay their eggs.

Scabies is easily cured, but only if patients and their close contacts conscientiously follow directions for medical treatment and environmental cleanup. However, even after a person is rid of the mites and their eggs, itching can persist for up to four weeks.

The scabies mite, Sarcoptes scabiei, can afflict a number of animals. In dogs and sheep, the infestation is commonly called mange.

Each species of animal has a specific variant of the mite, which cannot reproduce in other hosts. If your dog gets mange, as mine once did, you may be itchy for a while if the mites get into your skin, but the condition will cure itself when the adult mites die.

It's not so easy if you acquire the human scabies mite. At 0.4 millimeter in length, the mite is barely visible to the naked eye. But just 10 adult females breeding in a person's skin are enough to cause bodywide torment, as they defecate and lay eggs that then hatch into larvae and develop into more adult mites. The itching is due to an allergic reaction to the mite, its excrement and burrows, though an antihistamine alone is rarely enough to squelch the desire to scratch.

Scratching, however, can cause sores that become infected with bacteria like staphylococci or streptococci, prompting a diagnosis of impetigo and perhaps missing the underlying cause.

Scabies spreads most often through direct, prolonged skin-to-skin contact, like that between sexual partners and members of a household.

As the U.S. Centers for Disease Control and Prevention put it in a fact sheet on scabies, "A quick handshake or hug will usually not spread infestation." But the mite can also be acquired from contaminated bedding, clothing or towels recently used by a person with scabies.

Although an adult female mite can live on a person for up to a month, the mite rarely survives more than three days apart from a living body.

According to the American Academy of Dermatology, scabies has become a common problem among elderly people living in nursing homes and extended care facilities, where it can spread easily to attendants who in turn spread it to other residents. In the elderly, scabies is often mistaken for senile pruritus, itching caused by degenerative changes in aging skin.

Although taking a shower or bath soon after contact with live mites can wash them away, an attack of scabies is not a symptom of poor hygiene. Literally anyone can get it, regardless of age, sex or social class. The mites can neither fly nor jump but rather crawl at a rate of 2.5 centimeters a minute on warm skin, Dr. Olivier Chosidow of the Université Pierre et Marie Curie in Paris reported in The New England Journal of Medicine in April 2006.

When a doctor is familiar with scabies, as most dermatologists should be, the diagnosis is relatively simple. The scabies mite has favored sites in which it lives, generally areas on the body that are warm or where clothing is tight: between fingers and under nails; in the folds of the wrist, elbow and knee; on the buttocks; around the belt line and nipples; and on the penis

When children get scabies, the lesions tend to appear bodywide, including the scalp, palms and soles. A particularly severe, highly contagious form called crusted, or Norwegian, scabies can affect the elderly, AIDS patients and people on immunosuppressants. While people with ordinary scabies usually have no more than 5 to 15 live female mites on their bodies, those with crusted scabies can harbor hundreds, even millions, of adult mites.

The usual treatment is to apply a 5 percent permethrin cream to cool, dry skin from the neck to the bottom of the feet. The cream must be applied everywhere, including the groin, palms and soles and between fingers and toes. The medication, an insecticide, should be left on for 8 to 14 hours, with a possible second application a week or two later in case some eggs survived and had hatched.

Permethrin, a synthetic form of pyrethrin, a natural insect-killing plant chemical, is considered safe for infants and pregnant women, though a 10 percent sulfur ointment and crotamiton cream may be used for infants. To treat the crusted form, an oral medication, ivermectin, is usually prescribed, with a second dose given two weeks later.

In addition to mite-killing medicine, antihistamines and calamine lotion are commonly used to relieve the itching.

To ensure successful eradication of the mites, all members of the household, close friends and sexual contacts must be treated simultaneously. In institutional settings like nursing homes or day care centers, all residents and workers must be treated at the same time. All bedding, towels and clothing used by those infested or potentially infested within three days before treatment must be washed in hot water and dried on high heat or dry-cleaned.

source: herald tribune

Scientists Turn Human Skin Cells Into Insulin-producing Cells

The breakthrough may one day lead to new treatments or even a cure for the millions of people affected by the disease, researchers say.

The approach involves reprogramming skin cells into pluripotent stem cells, or cells that can give rise to any other fetal or adult cell type, and then inducing them to differentiate, or transform, into cells that perform a particular function – in this case, secreting insulin.

Several recent studies have shown that cells can be returned to pluripotent state using "defined factors" (specific proteins that control which genes are active in a cell), a technique pioneered by Dr. Shinya Yamanaka, a professor at Kyoto University in Japan.

However, the UNC study is the first to demonstrate that cells reprogrammed in this way can be coaxed to differentiate into insulin-secreting cells. Results of the study are published online in the Journal of Biological Chemistry.

"Not only have we shown that we can reprogram skin cells, but we have also demonstrated that these reprogrammed cells can be differentiated into insulin-producing cells which hold great therapeutic potential for diabetes," said study lead author Yi Zhang, Ph.D., Howard Hughes Medical Institute investigator, professor of biochemistry and biophysics at UNC and member of the Lineberger Comprehensive Cancer Center.

"Of course, there are many years of additional studies that are required first, but this study provides hope for a cure for all patients with diabetes," said John Buse, M.D., Ph.D., president of the American Diabetes Association and professor and chief of the endocrinology division in the UNC School of Medicine's department of medicine.

About 24 million Americans suffer from diabetes, a disease that occurs when the body is unable to produce or use insulin properly. Virtually all patients with type I diabetes, the more severe of the two types, must rely on daily injections of insulin to maintain their blood sugar levels.

Recent research exploring a possible long-term treatment – the transplantation of insulin-producing beta cells into patients – has yielded promising results. But this approach faces its own challenges, given the extreme shortage of matched organ donors and the need to suppress patients' immune systems.

The work by Zhang and other researchers could potentially address those problems, since insulin-producing cells could be made from diabetic patients' own reprogrammed cells.

Zhang is collaborating with Buse to obtain skin samples from diabetes patients. He said he hoped his current experiments will take this approach one step closer to a new treatment or even a cure for diabetes.

The research was funded by the Howard Hughes Medical Institute and the National Institutes of Health. Study co-authors include postdoctoral fellows Keisuke Tateishi, M.D.; Jin He, Ph.D.; Olena Taranova, Ph.D.; Ana C. D'Alessio, Ph.D.; and graduate student Gaoyang Liang, all from the UNC School of Medicine's department of biochemistry and biophysics.

source: science daily

Urology discovers it, too, has a feminine side

The urology rotation during my third year of medical school might best be described as a boys' club, often characterized by infighting, one-upmanship and sexual humor. It was a little off-putting to many students, but always entertaining.

So imagine my surprise when a female medical student recently told me that she loved her urology rotation, in which she found the doctors to be especially humanistic and caring. A big part of the reason, she believed, was the growing presence of women among her teachers. It turns out that the field is undergoing a gender transformation.

Urologists, who are specialists in the organs that produce urine, have always cared for women. After all, as Dr. Jennifer Gruenenfelder, a urologist in Laguna Hills, California, reminded me in an e-mail message, "Women have kidneys and bladders and urethras and ureters, too."

Yet even as more and more women entered medicine in the late-20th century, urology continued to overwhelmingly attract male applicants.

Not until 1962 did a woman - Dr. Elisabeth Pickett - become a board-certified urologist. By the mid-1980s, the United States had only 22 female urologists.

There were several explanations. For one thing, the stereotypical urology patient has always been a man, suffering from an enlarged prostate, prostate cancer or erectile dysfunction. The demanding hours of surgical fields like urology probably discouraged many female medical school graduates from applying, and the lack of female mentors and role models did the same.

Finally, when women did express interest, they were often met with little enthusiasm. In a 1997 survey of female urologists conducted by Dr. Christine L. Bradbury and colleagues at the University of Utah School of Medicine, 44 percent of respondents reported having been discouraged from entering urology because of their sex. Gruenenfelder said that a female dean at her medical school had told her that applying for a specialty in urology was "a bad idea."

At the same time, some urologists eagerly supported the entrance of women into their field. Dr. Harriette Scarpero of Vanderbilt University, the president of the Society of Women in Urology, said her urology mentors were superb doctors and excellent teachers. "My choice of urology," she told me, "had as much to do with the influence of those special teachers as it did with my love of surgery."

And once the pioneers arrived, more women followed. The Society of Women in Urology has more than 300 members, and Scarpero estimates that 20 percent of urologists in training are now women. A female urologist who calls herself Dr. Keagirl has even created a Web site, UroStream (urostream.blogspot.com), that discusses the "ever humorous field of urology."

But old barriers and stereotypes do not simply disappear. Dr. Kristin Kozakowski, now a pediatric urology fellow at the University of Toronto, was one of three women who made up the entire recent graduating class of urology residents at Columbia University Medical Center. Though she praised the professionalism of her senior male colleagues, she said she still felt awkward around them. "It is as if they still want to engage in bathroom humor but cannot do so around women," she said.

And she reports resistance from another group of males: certain patients who either thought she was a nurse or asked to see a male urologist. Gruenenfelder recalls being called "babe," "sweetheart" and "honey" during her training.

Both doctors acknowledge that special issues of modesty exist when they examine male patients. It is difficult for many men to undress in the presence of a woman and then submit to an examination of their private parts.

But just as there have been male gynecologists for decades, there are now female urologists. As Kozakowski politely tells reluctant patients, "I'm the doctor who is here."

source: herald tribune

Bacteria Ready to Make Plastic From Sugar

Claims of biology-based oil and plastic usually bear the caveat "in five years." But a San Diego-based company claims they will have a pilot plant for production of E. coli-based 1,4 butanediol (BDO), the base chemical for plastic products ranging from Spandex to car bumpers, next year.

"We are able to couple the growth of the organism to the production of BDO," said Christophe Schilling, co-founder of the company, Genomatica. "For the bacteria to grow they have to produce BDO."

The announcement holds particular promise amid rising oil prices and a scramble to replace petroleum-based ingredients with renewable ones.

Traditionally, BDO is made from oil and natural gas through an energy-intensive process. Genomatica, founded in 2000, says their technology can significantly reduce the cost of making BDO. All they need is sugar and a particular bacterium.

The specific cost saving will vary by company, but Chris Gann, Genomatica's CEO, says that, "if the price of oil dropped to $50 per barrel [our technology] would still be competitive." The price for a barrel of oil earlier this week was about $120.

That savings in cost comes from using cheaper raw materials and less energy to trigger the chemical reactions necessary to turn oil into plastic, Gann said.

Using computer-aided design (CAD) software similar to what engineers have used for years, Genomatica scientists simulated various chemical reactions to find the best genes for the job.

Schilling won't say from which specific organisms they got the proteins and enzymes used to turn sugar into BDO, other than that they culled them from a computer database of "hundreds of microorganisms," some obscure, some commonplace.

Once Genomatica scientists had a working virtual E. coli, they spliced the selected genes into the real E. coli and turned them loose on raw cane sugar.

So far, Genomatica has produced less than two pounds of BDO. To create industry-scale amounts of BDO, cane sugar, E. coli and water will go into 105-degree (Fahrenheit) fermentation tanks, like the ones used to produce ethanol.

Still, cells are notorious for evolving unwanted traits, like the rise of drug resistant bacteria and cancers. Schilling said they plan to tap into that evolutionary bent and turn it into profit.

"We have ways to essentially accelerate [evolution], so the bacteria can evolve to tolerate higher concentrations of BDO and not in the exact way we would have predicted with the computer models," said Schilling.

Genomatica will make the E. coli, but not at the plants where the BDO is produced. Instead, the company will license the genetically engineered E. coli to companies worldwide who create BDO-based products. The company can even custom design E. coli that take advantage of local sugar variations. The first pilot plant is set for next year, according to Genomatica.

Next year might be a bit ambitious, suggested Harvey Blanch, a professor of chemical engineering at the University of California, Berkeley. Blanch said a longer time line, as in a couple of years, was more likely, but that he was still quite excited by the development.

"This is a very interesting opportunity to get a new source of raw materials that could replace chemical processing with biological engineering," said Blanch. "Using this technique everything from new kinds of plastics to jet fuel could be produced with less energy and smaller environmental costs."

Genomatica hopes that bio-BDO is just the first of these new raw materials. Currently, the company is pursuing more than six other unspecified chemicals, all of which have a larger market than the $4 billion annual BDO market.

"What gets us really excited is that this opens up the door to go after other chemicals that aren't produced in nature," said Schilling.

source: discovery channel

Virus-Based Batteries

A virus-ridden computer without a noticeable battery might not sell on Ebay, but that's exactly what researchers at MIT could build, thanks to a new advance in battery technology.

By pouring a mixture of the harmless, genetically engineered M13 virus and the metal cobalt over stamped silicon film, Angela Belcher and her colleagues created a flexible, microscopic battery that could be cheaply mass produced.

In theory, it could turn virtually any surface -- from large computers to tiny implanted detectors for cancer or heart disease -- into an energy-storing device.

"The idea of using stamping technique to produce a battery is pretty different," said Belcher. "We can make the batteries really small, which lets us put a power source on all sorts of tiny sensors."

Belcher and her colleagues created the first virus-powered battery in 2006. Since then they have been refining their viral battery while working to create other novel energy-storing devices that could be woven into fabrics or poured into containers.

Their most recent advance, detailed in the Proceedings of the National Academy of Sciences, involves stamping a base material, in this case silicon, so that the negatively charged M13 virus and positively charged cobalt can self-assemble based on their relative charges and the pattern of the stamp.

Stamping the base materials, which can theoretically be nearly any surface, means that the batteries can be produced more cheaply and efficiently. With silicon as the base material, flexible and curved batteries can be created as well.

Gram for gram, the virus-based batteries are roughly twice as powerful as traditional chemical batteries, said Belcher, although the battery cells are so small -- about four microns across -- that exact measurements are difficult. It takes about an hour for an M13 battery to form.

While one tiny cell can't hold much energy, when many cells are combined they can power real devices.

Nine months ago Belcher created a button-sized, M13-based battery and put it into her laser pointer. After numerous recharges she is still on her first virus-based battery.

"It hasn't failed yet," said Belcher.

Like her laser-pointer battery, other virus-based batteries would be rechargeable and more environmentally friendly that traditional batteries. The virus batteries are assembled at room temperature, have a relatively neutral pH, and use smaller amounts of potentially troublesome metals like lithium or cobalt.

Because the batteries are so small they will first be used to power small things, such as lab-on-a-chip technology and implantable devices that would monitor patient health, say Belcher and other researchers.

"This technique has tremendous potential to monitor diseases like cardiovascular disease and cancer," said Kimberly Kelly, an oncologist at the University of Virginia. After chemotherapy or surgery for cancer, patients must be monitored to ensure the cancer doesn't return.

In theory, a small device implanted under the skin, powered by M13, could detect proteins produced by renewed cancer cells. In response, it could light up (literally, by triggering a small visible LED, as one example), alerting both patient and physician. It would be like a check engine light for cancer or heart attacks.

"[Belcher] is pretty close to developing this technology for light-based applications," said Kelly. "I could see them coming out in two years, five years at worst."

Eventually Belcher hopes to scale up virus-based batteries for larger devices like computers or even cars that wouldn't need a separate battery; the battery would instead be built into the surface of the car itself.

"It would be part of the manufacturing process," said Belcher. "What we do is provide the surface and the ions, and the batteries built themselves."

source: discovery channel