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Biomedical subjects

J A Perry

Publications and source records attributed to J A Perry.

4 recordsLinked to original sources
PubMed1990

Sensitive trace-first liquid chromatographic determination of 4-aminopyridine in 3,4-diaminopyridine.

For the treatment of human neuromuscular diseases, 3,4-diaminopyridine (DAP) is six to ten times more effective than 4-aminopyridine (AP), but only half as convulsant and toxic. Therefore, there is a need for the determination of AP in DAP. With only conventional equipment, high-pressure liquid chromatography can be used for the extremely sensitive detection of a trace contaminant under one condition: that is, the trace must be eluted before the major component it contaminates. Prior elution presents a trace peak in a fully exploitable form that is maximally efficient and maximally observable. This has already been demonstrated with a Pirkle-concept chiral stationary phase for determination of a chiral trace. However, its application to determination of a nonchiral trace with a reversed phase has not previously been reported. Such an application is reported here. In this demonstrative study, selectivity and loading capability were iteratively improved. Ion pairing with dodecanesulfonate maximized selectivity. It was again shown that using a less concentrated sample in greater volume maximizes loading capability without obscuring the peak of the trace. Eventually, the ability to detect 0.005% AP in DAP was demonstrated. Whether that sensitivity might be improved still more, perhaps with a larger column, was not established.

4-Aminopyridine↗
PubMed1979

Pesticide and PCB residues in the upper Snake River ecosystem, Southeastern Idaho, following the collapse of the Teton dam 1976.

The Teton Dam in Southeastern Idaho collapsed on June 5, 1976. The resulting flood damaged a large area and caused the release of toxicants into the Snake River. A pesticide recovery team in a helicopter worked the flooded area for three weeks and collected 1,104 containers, about 35% of which contained toxicants. It was estimated that less than 60% of the lost pesticide containers were recovered. This paper addresses the results of a one-time sampling effort designed to determine the magnitude of the chemical contamination. Over 300 samples of fish, plankton, waterfowl, sediments, water, stream drift, aquatic plants, and soil were taken. Pesticide residues were measured as microgram/kg (ppb) wet weight, whole animal basis. Rainbow trout had as much as 1432 micrograms/kg total DDT plus analogs, 66 micrograms/kg dieldrin, and 1010 micrograms/kg PCBs. Utah suckers had up to 1420 micrograms/kg total DDT plus analogs, 32 micrograms/kg dieldrin, and 1800 micrograms/kg PCB. Rocky Mountain whitefish had as much as 2650 micrograms/kg total DDT and analogs, 30 micrograms/kg dieldrin and 1400 micrograms/kg PCBs. These PCB and DDT levels were high, approaching the 2,000 micrograms/kg FDA proposed tolerance, but were below the 5,000 micrograms/kg present tolerance. Dieldrin levels were low and organophosphates were undetectable. An undeveloped area (the Fort Hall Bottoms) showed higher levels of contaminants than did an industrialized area (the lower Portneuf River). This apparent discrepancy remains unexplained. Very little pre-flood data on a whole fish basis were available for comparison (Johnson et al 1977). However, it does not appear that any human health hazard due to pesticide levels exists in this portion of the Snake River.

Animals↗
PubMed1976

Physicians' erotic and nonerotic physical involvement with patients.

The author surveyed 164 female physicians to determine their attitudes and practices regarding erotic and nonerotic physican contact with patients. Compared with a previous study of male physicians (1), more female physicians believe in and engage in nonerotic touching, but fewer believe in and engage in erotic touching. None of the female physicians reported sexual intercourse with patients as compared with 11% of the male physicians in the previous study.

Adult↗