In this study we were able to distinguish 10 schizophrenic subjects from 10 control subjects with 100% accuracy by measuring plasma dehydroepiandrosterone (DHEA) diurnal rhythms and analyzing the data using a linear function equation. Discrimination with this high level of accuracy is in contrast to most studies of altered biological functioning in schizophrenia which have yielded inconsistent results. These findings are regarded as preliminary; further study is necessary to elicit any consistent DHEA disturbance in schizophrenics and to discover the significance for the pathophysiology of the illness. Measurements of plasma cortisol, aldosterone, DHEA-SO4, and testosterone did not provide such a basis for discrimination.
Water samples were collected between 1999 and 2000 from wetlands in Minnesota that contained malformed frogs. The water samples were analyzed for 14 minerals/ions and screened for the presence of biologically active compounds using Xenopus laevis. Results indicated that water from two sites, CWB and ROI2, induced severe retardation with embryo lengths reduced 20% after 96 hr of development. The developmental delay observed with water from ROI2 was alleviated by supplementation with sodium, while both sodium and potassium alleviated the developmental delay observed with water whose mineral content mimicked that of CWB. Seasonal fluctuations in the sodium and potassium content at ROI2 and NEY correlated with changes in the rates of Xenopus development. Xenopus embryos reared on water from ROI2 for 120 hr displayed gut malformations not present in embryos reared on a synthetic media designed to mimic the mineral content of the water from ROI2. Embryos reared on water from ROI2 supplemented with minerals at levels comparable to that routinely employed in the rearing of Xenopus were neither retarded nor malformed. It is proposed that climate driven hydrology may influence the mineral composition at selected wetlands and delay development which may alter window(s) of susceptibility towards biologically active agents and the occurrence of malformed frogs.
Between 1995 and 1997 over 62% of the counties in Minnesota reported the presence of malformed frogs. While most sites have recently shown a decline in malformed frog populations, one site in northeastern Minnesota with no prior history of malformed frogs was recently discovered to contain > 67% malformed Rana pipiens (northern leopard frogs). As part of an effort to study the presence of hormonally active agents in fresh water sources, water samples were collected from lakes in Minnesota containing malformed frogs and analyzed for the presence of biologically active compounds using a novel evanescent field fluorometric biosensor and the frog embryo teratogenesis assay: Xenopus (FETAX) bioassay. The waveguide based biosensor developed by ThreeFold Sensors (TFS biosensor, Ann Arbor, MI) monitors the interaction between free human ER-α and an estrogen immobilized on a sensor fiber. Inhibition of the interaction reflects the presence of estrogenic compounds. The FETAX bioassay is a developmental assay, which measures teratogenicity, mortality, and inhibition of growth during the first 96 hours of organogenesis and thereby provides a universal screen for endocrine disruptors. TFS biosensor and FETAX screening of the water samples suggest a relationship between estrogenic activity, mineral supplementation, and the occurrence of malformed frogs.
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