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Biomedical subjects

A S Greenstein

Publications and source records attributed to A S Greenstein.

5 recordsLinked to original sources
PubMed1995

Glutathione disulphide as a marker of reperfusion injury in ischaemic skin flaps.

Estimation of the oxidised form of glutathione (GSSG) in an ischaemic/reperfused organ is frequently employed as an indicator of oxidative stress created by the production of oxygen free radicals during the reperfusion period. The time course of oxidative stress and tissue damage in 19 ischaemic/reperfused guinea-pig island skin flaps was evaluated. No-flow ischaemia was induced in the flaps for 6 h in 7 animals, and for 8 h in 9 animals (a further 3 animals served as controls without ischaemia). Arterial and venous blood samples were obtained directly from the flap pedicle at baseline, 10, 30, and 60 min following reperfusion. Results suggest that a second focus of oxidative injury, possibly mediated by activated neutrophils, contributes to the overall process of reperfusion injury. Plasma levels of GSSG allow for a more sensitive quantification of oxidant stress within reperfused ischaemic flaps, and may serve as a useful tool in skin flap research.

Animals↗
PubMed1993

Effects of an aromatase inhibitor on thymus and kidney and on oestrogen receptors in female MRL/MP-lpr/lpr mice.

The effects of an aromatase inhibitor, 4-hydroxyandrostenedione (4-OHA), which blocks oestrogen formation, have been studied in female MRL/MP-lpr/lpr mice which are a model of SLE. At 11.5 weeks, mice were implanted subcutaneously either with empty Silastic implants or with implants containing 25 mg 4-OHA. At 15 weeks, they were sacrificed by decapitation and liver, thymus, kidneys and uterus taken for wet weight, histology and measurement of cytosolic and nuclear oestrogen receptors. Thymus weights were significantly lower in 4-OHA-treated mice although uterus weights were similar in both groups. Also, whereas thymuses from control-treated mice were packed with plasma cells with abundant cytoplasm, those from 4-OHA-treated mice contained T cells with large nuclei. Relative oestrogen receptor abundances were: uterus > liver > thymus, although cytosolic receptors could not be detected in thymus cytosols of MRL mice unless they were treated with the aromatase inhibitor. In kidney, there was histological evidence that inflammation was limited to mesangium in 4-OHA-treated mice. These results support the hypothesis that oestrogens may be involved in the aetiology of murine SLE and provide data suggesting that substances which block oestrogen production in vivo may be useful to treat certain forms of SLE.

Androstenedione↗