In a rare clinical project sponsored by the national
Superfund basic research program, reproductive physiologist Bill Lasley is developing methods to monitor human reproductive health. His long-range objectives are to develop and improve laboratory tests that reveal the occurrence of reproductive problems such as miscarriage and abnormal ovulation among various populations, including groups of industrial workers.
A critical step in developing the tests, explains Lasley, is the selection of a measurable substance in specimens from human subjects that correlates with a known reproductive event, such as pregnancy. (Steven Nakajima's work, described in the main article, is an integral part of this step.) "Most often these substances, or 'biomarkers,' are hormones or metabolic by-products of hormones," said Lasley. When biomarker tests are conducted, usually over a period of days or weeks, the resulting data must be capable of revealing that something abnormal has occurred in the reproductive event.
Most of the tests Lasley and his colleagues develop measure biomarkers in urine samples because urine is relatively easy for people to collect, store and ship to a testing facility.
Once a biomarker test has been validated in clinical studies, and streamlined for use with large numbers of people, it can be used in epidemiologic studies. One such study in the semiconductor industry was prompted by concern that women who are exposed to the "clean room" conditions necessary for manufacturing computer chips may have an increased rate of early miscarriage. The study used biomarker tests developed by Lasley's group that reveal the occurrence of early miscarriage. Because the tests were much more sensitive than over-the-counter pregnancy tests, they detected a pregnancy and subsequent miscarriage before the woman was aware she was pregnant.
Lasley says the study did not show that exposure to a clean room is necessarily a risk for early pregnancy. "But I should couch that carefully because our numbers were very low. The economy was bad--the industry was laying off people--and the planned pregnancy rate [during the study] was very low."
In doing the study, Lasley and his colleagues developed procedures to collect, store, track and analyze over 70,000 urine samples. Epidemiologists in this country and others are now adapting the methodology for other population-based studies. For example, studies in China will monitor the reproductive health of both men and women in occupational settings that may be hazardous.
Besides developing human biomarker tests, Lasley is spearheading the development of tests to identify chemicals in the environment that adversely affect reproduction. Such testing could be an invaluable safeguard for human reproductive health.
Photo by Debbie Van Blankenship/UC Davis Creative Communications Services