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J T Du

Publications and source records attributed to J T Du.

7 recordsLinked to original sources
PubMed1984

Sex differences in arachidonate cyclo-oxygenase products in elicited rat peritoneal macrophages.

Peritoneal macrophages were elicited by Freund's incomplete adjuvant from adult male and female Fisher 344 rats. The release of prostaglandin E2 and thromboxane B2 from these macrophages was determined by radioimmunoassay. The basal release of these products was the same for males and females. The macrophages of the female rats released, in a dose-dependent manner, significantly more prostaglandin E2 and thromboxane B2 than macrophages from the male, following challenge with either a particulate stimulus, zymosan (25-150 micrograms/ml) or a soluble stimulus, calcium ionophore A23187 (1 X 10(-7) -1 X 10(-6) M). These results may relate to gender differences in immune responses.

Animals↗
PubMed1983

Human peritoneal macrophages synthesize leukotrienes B4 and C4.

Macrophages were isolated from the dialysis fluid of patients undergoing continuous ambulatory peritoneal dialysis and separated by gradient centrifugation and purification on 50% Percoll. The cells were prelabeled with [14C]arachidonic acid for 1.5 h. The labeled cells were then incubated with calcium ionophore A23187 (1 microM), serum-treated zymosan (200 micrograms/ml), and a lipoxygenase inhibitor, nordihydroguairetic acid (1 X 10(-5) M). The arachidonate metabolites in the medium were separated on Sep-Pak columns, and finally purified by reverse-phase high-pressure liquid chromatography (HPLC). The labeled products co-chromatographed with authentic leukotriene B4 and leukotriene C4 standards. Serum-treated zymosan and A23187 significantly stimulated and nordihydroguairetic acid significantly inhibited leukotriene synthesis. Leukotriene D4 was not detected, which suggests that these cells contain low gamma-glutamyltranspeptidase or high dipeptidase activity. These results establish, for the first time, that human peritoneal macrophages synthesize the lipoxygenase products, leukotriene B4 and leukotriene C4.

Centrifugation, Density Gradient↗
PubMed1979

Biochemical alterations in livers of rats exposed to vinyl chloride.

Sprague-Dawley rats were exposed to vinyl chloride to determine the earliest sequential biochemical changes occurring with liver injury before anglosarcoma development. Activity of glucose-6-phosphatase, a key gluconeogenic enzyme in the liver microsomal fraction, decreased 25% with respect to controls after 70 h of exposure. Glucose-6-phosphate dehydrogenase activity increased twofold after more than 100 h of exposure. Nonprotein sulfhydryl levels (glutathione and/or cysteine) showed a slight but progressive elevation, whereas glutathione reductase activity increased 50-60% during exposure to vinyl chloride.NADPH-cytochrome c reductase and mixed function oxidase were unchanged in the same microsomal fraction. There markers of liver mitochondrial, cytosol, and microsomal function. No significant histological changes were found on light microscopic examination during this exposure period. However, with electron microscopy, dilation of rough endoplasmic reticulum was seen in the animals exposed for more than 137 h. These enzymatic changes are considered to reflect early hepatocellular adaptation to vinyl chloride exposure with very mild or limited hepatocellular injury in its earliest stage.

Animals↗