Officials at the National Institute of Allergy and Infectious Diseases at the National Institutes of Health said embryonic stem-cell research for HIV/AIDS treatments is not being pursued now.
Stem cells are immature human cells that can differentiate into functional cells and hold the promise for new treatments for diabetes, Parkinson's disease and Alzheimer's disease, among others.
Stem cells can be derived from adult tissue, fetal tissue and embryonic tissue, and the latter two sources have generated debate about the ethics of their use.
Federal funding is banned for research using embryonic tissue, and the president is considering whether to lift that ban.
Among the proposals is extraction of stem cells from embryos scheduled for disposal at the nation's fertility clinics.
A Virginia company, the Jones Institute for Reproductive Medicine in Norfolk, in July announced it was extracting stem cells from embryos created specifically for research, using donated eggs and sperm. The Jones Institute used private funding for this research.
Although the use of embryonic and fetal research is opposed by many anti-abortion groups, several Republican senators who oppose abortion, including Orrin Hatch of Utha, Strom Thurmond of South Carolina and Bill Frist of Tennessee, have urged Bush to lift the ban on embryonic research - with appropriate guidelines in place.
Tommy G. Thompson, secretary of health and human services, also has endorsed funding for embryonic stem-cell research.
One proposed compromise would allow federal funding for research with embryonic stem-cell lines or colonies, already in existence, regardless of their original source.
But Bush, during his recent European tour, was asked by Pope John Paul II to life the ban, and the House voted in June to ban all cloning including cloning of embryonic cells for research.
Researchers indicate that while stem-cell research is under way for HIV/AIDS treatment, such research generally involves use of adult stem cells and specifically hematopoietic stem cells that are derived from bone marrow. Hematopoietic stem cells can differentiate into blood and immune cells.
Research is under way into the use of these hematopoietic stem cells to help restore the immune systems of people with AIDS.
NIAID officials are studying whether these stem cells can be extracted from a patient, genetically modified and replaced in the same patient.
NIAID officials said they were not aware of any research involving embryonic stem cells and HIV/AIDS therapy or vaccines.
SCID-hu mouse
AIDS researchers have been using fetal tissue in their research with the severe combined immunodeficiency defect-hu mouse model.
The SCID-hu mouse has no natural immune system, and researchers have used fetal liver and thymus tissue to develop a human immune system in the mouse.
The SCID-hu mouse provides opportunities to study HIV/AIDS infections and therapies in a living subject, researchers said.
Jerome A. Zack, associate professor of microbiology, immunology and molecular genetics at UCLA, said his research involves use of fetal and adult hematopoietic stem cells with the SCID-hu mouse.
His laboratory is examining factors involved in immune restoration after drug therapy, and novel therapeutic approaches such as gene therapy, Zack said.
Although AIDS researchers do not use embryonic stem cells, Zack said, advances in embryonic stem-cell research might aid their work.
"Should scientists find ways to induce human embryonic stem cells to differentiate through all hematopoietic lineages - to my knowledge this had not been accomplished yet - these cells would be of major importance to the HIV research community," he said.
Bush has not indicated when he will make a decision on embryonic stem-cell research funding.
University of Wisconsin researchers have demonstrated that they can differentiate embryonic stem cells into blood cells.
That is preliminary to differentiation into T cells, which would be highly significant to HIV/AIDS research, said Jerome A. Zack, associate professor of microbiology, immunology and molecular genetics at UCLA.
The Wisconsin researchers, who published their findings Sept. 3 in the Proceedings of the National Academy of Sciences, said the use of embryonic stem cells could provide a novel source of blood cells for transplantation and transfusion.
Officials at the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, have indicated embryonic stem-cell research for HIV/AIDS treatment is not being pursued now.
Stem cells are immature human cells that can differentiate into functional cells. They hold the promise of new treatments for diabetes, Parkinson's disease and Alzheimer's disease, among others.
Stem cells can be derived from adult tissue, fetal tissue and embryonic tissue. The latter two sources have generated debate about the ethics of their use.
President Bush has agreed to use federal funding for embryonic stem-cell research, but only for stem-cell lines or colonies already in existence.
Bush said he would not allow public funding for creation of new stem-cell lines through destruction of human embryos. Proposed was the extraction of stem cells from embryos slated for disposal at fertility clinics.
The NIH has identified 64 stem-cell colonies in the United States and around the world.
However, in testimony before the Senate Committee on Health, Education, Labor and Pensions in early September, Tommy G. Thompson, secretary of health and human services, acknowledged that only 24 or 25 lines now are available for research.
He predicted all of the lines eventually will be available for research.
Senators questioned Thompson about whether an adequate number of stem-cell lines is available, whether the lines have faced contamination from mouse cells used to provide nourishment, and how public-private partnerships will work in conducting the research.
Thompson said he does not think contamination of the stem-cell lines has occurred.
He also said agreements will be available to allow private companies to license basic findings for commercial development.
"I don't think the privates are going to do the basic research," Thompson said.
Thompson described the stem-cell differentiation into blood cells as "truly exciting. That's a real breakthrough."
Researchers indicate that while stem-cell research is underbway for HIV/AIDS treatment, such research generally involves the use of adult stem cells, specifically, hematopoietic stem cells. These are derived from bone marrow. Hematopoietic stem cells can differentiate into blood and immune cells.
Research is under way into the use of hematopoietic stem cells to help restore the immune systems of people with AIDS. NIAID researchers are studying whether these stem cells can be extracted from a patient, genetically modified and replaced in the same patient.
NIAID officials said they are not aware of any research involving embryonic stem cells and HIV/AIDS therapy or vaccines.
"Innovative approaches must be developed that aim not only to reduce the numbers of young adolescents having sex, but also to break the pattern of sustained risk-taking among those who resist messages to abstain," said the study in Family Planning Perspectives, from the Alan Guttmacher Institute.
Authors of the study were Lydia O'Donnell and Carl R. O'Donnell of the Education Development Center Inc. in Newton, Mass., and Ann Stueve, associate professor of clinical epidemiology at Columbia University in New York.
Minority youth
Although the age of initiation for sexual activity generally has stabilized in the United States, a survey of students in Brooklyn, N.Y., showed that's not the trend among minority youth.
The survey included a sample of 1,287 urban minority adolescents in the seventh and eighth grades, and a follow-up with 970 students in the 10th grade. The Reach for Health Study included students in the seventh grade in 1994-1995 and 1995-1996. It followed them to the 10th grade.
Among the findings:
Consequences
"This is of concern because early initiation of sexual intercourse places adolescents, particularly females, at elevated risk of being involved in an unintended pregnancy, of acquiring HIV or another sexually transmitted disease, and of other negative social and psychological outcomes," the study said.
The study also noted that rates of HIV and other STDs are increasing most rapidly among minority youth. Unintended pregnancies, while in decline overall, remain disproportionately high in these populations as well.
"As the accumulated experience of decades of HIV, STD and pregnancy prevention research shows, the need to address problems related to sexuality must be embraced at the community level, by families, by schools and by other organizations," the study said.