Possible embryonic stem cell option

CHAMPAIGN, Ill. - Sperm cell precursors can be converted into other cell types, providing a possible alternative to the medical use of embryonic stem cells, U.S. researchers say. The University of Illinois research, described in the journal Stem Cells, improves on earlier research that showed that a kind of germ cell that leads to the production of sperm could eventually give rise to a few cells that looked and acted like embryonic stem cells. But the earlier process with the spermatagonial stem cells took months, and only a small portion of the cells evolved into "embryonic stemlike"
cells, veterinary biosciences Professor Paul Cooke and post- doctoral researcher Liz Simon said. In their new research, Simon placed spermatagonial stem cells from inbred mice on the connective tissue in embryos and grafted the combination into living mice. They found that the spermatagonial stem cells, under the right conditions, formed new tissues that had all the physical characteristics of prostate, skin or uterus and produced the telltale markers of those tissue types, they said. The original cells stopped looking and behaving like spermatagonial stem cells, Cooke said. Cooke said he hopes a more streamlined approach can be developed to produce new skin cells or other tissues when needed -- for example, to replace skin damaged in a burn. His team is also investigating the use of ovarian stem cells instead of spermatagonial stem cells to see if they can get the same results with ovarian tissue.

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Gene may be key in treating Ebola, anthrax

FORT DETRICK, Md. - U.S. Army medical scientists say they've determined a single host gene may be key in treating both Ebola and anthrax infections. The study, conducted at the Army Medical Research Institute of Infectious Diseases, in- dicates a minor reduction in levels of a gene known as CD45 can provide protection against the microbes that cause Ebola hemorrhagic fever and the bacterium that causes anthrax.
Taken together, scientists said the study's results suggest a common host restriction factor and a promising approach to drug development for treating two completely different infec- tions. The researchers said mice expressing reduced levels of
CD45 between 11 percent and 77 percent were protected against Ebola virus. In addition to an overall survival rate of 90 percent to 100 percent, the mice had reduced levels of virus load in the major organs, and had completely cleared the virus 10 days after challenge. In contrast, mice that had naturally occurring levels of CD45 -- or none at all -- suc- cumbed to infection within seven to eight days following challenge. Scientists said mice that expressed reduced levels of CD45 retained greater control of gene expression and im- mune cell proliferation following Ebola virus infection.
These factors contributed to enhanced viral clearance, in- creased protection against the virus and a reduction in cell death. The study is reported in the early online edition of the journal Cell Host and Microbe.

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Scientists offer new AIDS vaccine strategy

Scientists offer new AIDS vaccine strategy

ATLANTA - U.S. scientists say conventional AIDS vaccine strat- egies shouldn't be the only plans of action considered in the fight against the disease. Researchers at the Yerkes National Primate Research Center, located at Emory University, said their proposal is based on studies involving simian immuno- deficiency viruses in African non-human primates. "Developing an effective AIDS vaccine has eluded scientists because the virus is tricky," said Dr. Guido Silvestri, a Yerkes affili- ate scientist and director of clinical virology at the Uni- versity of Pennsylvania School of Medicine. Silvestri, along with Dr. James Else, associate director for veterinary re- sources at Yerkes, noted that more than 25 years after the discovery of the human immunodeficiency virus as the etio- logical agent of AIDS, no effective vaccine for the disease is available. The scientists liken the conventional vaccine strategy to using military might to destroy an enemy -- the virus. A less conventional strategy, Silvestry said, might be to persuade the enemy not to attack at all. Such alternative strategies could include development of AIDS vaccines that make infected individuals resistant to disease progression or resistant to the virus by reducing the number of cells the virus can infect, he said. The proposal appears as a commen- tary featured in the journal Nature Medicine.

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