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Biomedical subjects

S L Clark

Publications and source records attributed to S L Clark.

111 records · Page 7Linked to original sources

Amniotic fluid epidermal growth factor levels in normal and abnormal pregnancies.

OBJECTIVE: To determine the concentrations of epidermal growth factor (EGF) in amniotic fluid (AF) from women during late pregnancy, with and without pathophysiologic complications. METHODS: All AFs were collected by amniocentesis from the following groups: gestational age at least 38 weeks (n = 15); gestational age 36-37 weeks (n = 10); gestational age 35 weeks (n = 5); labor 34 weeks or less, delivered within 7 days (n = 10); labor 34 weeks or less, undelivered (n = 10); chorioamnionitis (n = 7); gestational age-matched controls (n = 7); term, in labor (n = 8); term, not in labor (n = 8); intrauterine growth restriction (IUGR) 38 weeks or more (n = 8); macrosomia at 38 weeks or more (n = 10). Epidermal growth factor was assayed using a specific radioimmunoassay. RESULTS: Amniotic fluid EGF levels increase rapidly in late pregnancy but are not altered by chorioamnionitis or by term or preterm labor. Intrauterine growth restriction is associated with lower EGF levels in AF, but macrosomia is without effect. CONCLUSIONS: Epidermal growth factor levels in AF are increased near term and decreased in pregnancies complicated by IUGR; they may be an indicator of specific maturational events.

Amniotic Fluid↗

Tissue and cellular alterations in Asian clam (Potamocorbula amurensis) from San Francisco Bay: toxicological indicators of exposure and effect?

The US Geological Survey has reported the presence of a metal contamination gradient in clam tissues, decreased condition indices, and irregular reproductive patterns have been reported in the Asian clam, Potamocorbula amurensis, from San Francisco Bay. If metals are driving the observed patterns in the field, then biomarkers of exposure, and possibly deleterious effect, should show a corresponding gradient. In this study, biomarkers from sub-cellular to tissue levels of biological organization were assessed in P. amurensis collected from the Bay or exposed to cadmium in the laboratory. Cellular and tissue alterations were assessed using histopathology and enzyme histochemistry (EH). Alterations in the ovary, testis, kidney, and gill tissues were most common at the most contaminated station when data were averaged over a 12-month sampling period. EH analysis indicated decreased active transport, energy status, and glucose oxidation in kidney and digestive gland at the most contaminated site which may indicate a decreased potential for growth. Ovarian lesions observed in feral Asian clams were experimentally induced in healthy clams by cadmium exposure in laboratory exposures. Our results suggest a contaminant etiology for tissue alterations.

Animals↗