FISHing cuts the angst in amniocentesis

Article Abstract:

In amniocentesis, amniotic fluid, which contains cells of a developing fetus, is withdrawn from the amniotic sac with a needle and syringe, and tested to obtain genetic information and detect genetic abnormalities in the fetus. It takes approximately two weeks to obtain the results of an amniocentesis. Integrated Genetics, a biotechnology company, has devised a technique that reduces the time before results are available to two days. This technique, known as FISH (fluorescent in situ hybridization), uses molecules of DNA containing the genetic information located in five regions of the chromosomes (structures which contain the genes coding for the genetic information). Ninety percent of birth defects related to chromosomal abnormalities, which the amniocentesis detects, are located in these five regions. In clinical trials of 500 samples of amniotic fluid, the FISH technique detected all the chromosomal abnormalities that were detected by amniocentesis. Less common chromosomal disorders can also be detected with the FISH test. Further research is being carried out to develop molecules that will detect these rarer abnormalities. This technique is being further developed so that the fetal cells can be obtained from the mother's blood. This new technique would negate the risk of spontaneous abortion that exists by invasion of the amniotic sac to obtain the sample of fluid. The level of fetal cells in the mother's blood is very low and methods to increase the concentration of fetal cells are being developed. It is expected that clinical trials using these methods will in be in progress in two years. (Consumer Summary produced by Reliance Medical Information, Inc.)

Methods, Chromosome abnormalities, Amniocentesis, Prenatal diagnosis

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One worked: the other didn't

Article Abstract:

Tay-Sachs disease, an inherited disease affecting one in 3,600 Ashkenazi Jews, is characterized by symptoms of nerve degeneration. Sickle cell anemia, an inherited disease affecting one in 400 American blacks is characterized by the presence of abnormal sickle-shaped red blood cells, and decreased numbers of normal red blood cells. In the early 1970s, the United States began programs of genetic screening for Tay-Sachs disease and sickle cell anemia. The Tay-Sachs program was successful because an effort was made to educate the community and religious leaders, who then educated the public. Testing was offered at convenient times through storefronts, synagogues, and community centers. Testing was directed at couples of childbearing age, and a prenatal test was also available. The number of children born with Tay-Sachs dropped from 50 to 100 in 1970, and to 13 in 1980. The sickle cell anemia program was unsuccessful, mainly due to the lack of education and counseling. People who tested positive as carriers thought that they were actually afflicted with the disease. The lack of confidentiality resulted in prejudice against carriers, particularly by insurance agencies. Because there was no prenatal test, carriers were told that the only way to prevent the disease was to avoid having children, and this resulted in charges of racism. The end result was that few people were actually screened for sickle cell anemia. These past experiences of genetic screening indicate the importance of education and counseling.

History, Sickle cell anemia, Genetic screening, Genetic testing, Genetic disorders, Tay-Sachs disease

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U.S. lags on birth control development

Article Abstract:

In the past three decades, no fundamentally new contraceptives have been introduced in the United States. While European women have implantable contraceptives which last for five years, and women in 40 countries can receive an injectable contraceptive effective for two months, women in the United States have fewer options including the pill, the IUD (intrauterine device), the diaphragm, and sterilization. Political and legal considerations will probably prevent any substantial changes in this situation until at least the year 2000. Some think the Food and Drug Administration (FDA) is too strict in its standards for contraceptives; these standards are more rigorous than those for most other drugs. Although the policy is based on the notion that contraceptives, unlike other drugs, are used by healthy women over extended periods of time, critics feel that the government has not given significant consideration to the benefits of contraception. Questions of potential liability are also inhibiting corporations from introducing new contraceptives. Recently, manufacturers of vaccines have been relieved of some liability concerns by legislation, but it is unlikely that similar legislation could be passed for contraception. All in all, American women will be limited to birth control methods considered by some to be "old-fashioned" for many years to come. (Consumer Summary produced by Reliance Medical Information, Inc.)

United States, Contraception, Birth control

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