Hispanic research: implications of the National Institutes of Health guidelines on inclusion of women and minorities in clinical research.

Researchers have new opportunities to increase Hispanic health research as a result of the requirements in the March 1994 National Institutes of Health (NIH) guidelines on inclusion of women and minorities (and their subpopulations) as subjects in the biomedical and behavioral research projects that NIH supports. These guidelines are summarized and their implications for research are discussed here. Investigators must include women and minorities in their research involving human subjects and also present outreach plans for recruitment and retention of Hispanic and other participants into this clinical research. When clinical trials are planned, they need to be designed to measure differences in intervention effect in subpopulations when warranted. Investigators are challenged to develop new studies to fill the gaps in our knowledge about how radical/ethnic/cultural factors affect health and disease in Hispanic subgroups. This knowledge is necessary for designing studies that are culturally sensitive, enroll appropriate numbers of Hispanic participants, and ensure that the benefits of the research are made available to the Hispanic community.

A strategy for cancer prevention and control research.

Cancer is an important cause of morbidity and mortality in industrial countries. Recently changes in life-style and the environment in developing countries have coincided with increases in the incidence of certain cancers which might be related to these factors. A strategy for the prevention of all such cancers is presented, which involves research in a sequence of five phases to identify suitable interventions and to confirm their effectiveness in population studies, prior to their application on a nationwide scale.

Glutamine synthetase adenylyltransferase from Escherichia coli: purification and physical and chemical properties.

The glutamine synthetase adenylyltransferase (EC 2.7.7.42), WHIch catalyzes the adenylylation and deadenylylation of glutamine synthetase in E. coli, has been stabilized and purified 2200-fold to apparent homogeneity. Sedimentation and electrophoresis studies show that the native enzyme is a single polypeptide chain of 115,000 +/- 5000 molecular weight with an isoelectric pH (PL) OF 4.98, a sedimentation coefficient (S20.w0) of 5.6S, and a molar frictional coefficient (f/f0) of 1.52. An alpha-helical content of approximately equal to 25% and approximately equal to 28% beta-pleated sheet and approximately equal to 47% random coil structures were estimated from circular dichroism measurements. The amino acid composition of the protein has been determined. The intrinsic tryptophanyl residue flourescence of adenylyltransferase is two fold greater than that of L-tryptophan; this property has been used to monitor ligand-induced conformational changes in the enzyme. Activators of the adenylylation reaction (ATP, L-glutamine, or the E. coli PII regulatory protein) produced an enhancement of fluorescence; alpha-ketoglutarate, an inhibitor of adenylylation and an activator of deadenulylation, caused a net decrease in fluorescence. The adenylytransferase has separate interaction sites for L-glutamine and the regulatory PII protein.