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E Sykes

Publications and source records attributed to E Sykes.

26 records · Page 2Linked to original sources

Effect of phospholipase C on high-molecular-mass alkaline phosphatase in serum.

Electrophoresis of some serum samples on polyacrylamide gel, followed by staining for alkaline phosphatase (EC 3.1.3.1), produces a band of activity at the gel origin. This high-Mr band consists of liver membrane fragments containing alkaline phosphatase and other enzymes. Alkaline phosphatase is closely associated with phosphatidylinositol in liver plasma membranes, and we have found that phospholipase C (EC 3.1.4.3) from Bacillus cereus, known to possess some phosphatidylinositol specificity, was able to release liver alkaline phosphatase from the high-Mr band. Two preparations of phospholipase C from Clostridium perfringens, however, which has no phosphatidylinositol specificity, had no effect on the alkaline phosphatase activity in the high-Mr band.

Adult↗

Glycosyltransferase levels in tumors metastatic to liver and in uninvolved liver tissue.

Elevated levels of three plasma glycosyltransferases were associated with neoplasia in cancer patients, notably those with tumor metastatic to liver. We examined levels of sialyltransferase, galactosyltransferase, and fucosyltransferase in metastatic tumor and apparently uninvolved host liver tissue in attempts to delineate possible sources of elevated plasma enzyme levels. Highest levels of fucosyltransferase activity were found associated with tumor tissue; in contrast, sialyltransferase and galactosyltransferase activity was often highest at the tumor-liver interface.

Female↗

Insulin and adenosine regulate the phosphatidylcholine concentration in isolated rat adipocyte plasma membranes.

Blockade of adenosine receptors by 3-isobutyl-1-methylxanthine or degradation of endogenous adenosine with adenosine deaminase increased the phosphatidylcholine concentration in isolated rat adipocyte plasma membranes, an effect which was suppressed by the phosphatidylethanolamine methyltransferase inhibitor, S-adenosyl-L-homocysteine, and reversed by the adenosine analogue, N6-(L-phenylisopropyl)-adenosine. For example, the addition of N6-(L-phenylisopropyl)-adenosine to adenosine deaminase pretreated plasma membranes rapidly lowered the concentration of phosphatidylcholine by 171 nmol/mg at 30 seconds compared to control. Insulin-induced stimulation of phospholipid methylation in membranes treated with 3-isobutyl-1-methylxanthine or adenosine deaminase was achieved only after the addition of N6-(L-phenylisopropyl)-adenosine. These results suggest that adenosine receptor occupancy inhibits phospholipid methylation, is required for insulin stimulation of phospholipid methylation, and may perhaps activate a phosphatidylcholine-specific phospholipase C or phospholipase D.

1-Methyl-3-isobutylxanthine↗

Bronchoalveolar lavage in a girl with Gaucher's disease. A case report.

A case of Gaucher's disease with pulmonary involvement occurred. Numerous Gaucher cells were seen in bronchoalveolar lavage (BAL) fluid on two occasions in a girl with Gaucher's disease and respiratory symptoms. The Gaucher cells resembled macrophages with eccentric, small, oval nuclei but were distinguished by their abundant cytoplasm with the characteristic "rumpled tissue paper" appearance. The Gaucher cells were in a cellular background composed mainly of macrophages. These cells stained strongly positive with periodic acid-Schiff stain. Electron microscopy revealed numerous intracytoplasmic, elongated, membrane-bound lysosomes containing the characteristic twisted tubular structures. Severe pulmonary involvement is seen infrequently in all types of Gaucher's disease, and it is especially rare in the adult and juvenile forms (types I and III). To our knowledge, Gaucher cells have never been found before in BAL fluid. This case shows that BAL can be a useful adjunct in diagnosing and following the progression of pulmonary involvement in patients with Gaucher's disease.

Bronchoalveolar Lavage Fluid↗

Autoantibodies to specific enzymes: a review.

There are two categories of autoantibodies to specific enzymes: immunoglobulin-complexed enzymes and circulating autoantibodies directed to enzymes in tissue or tissues. Immunoglobulin-complexed enzymes may result in elevated serum enzyme activity. They are found more frequently in elderly patients and have limited clinical significance. Immunoglobulin association with the enzyme must be demonstrated to distinguish this macroenzyme from other high molecular weight enzyme complexes. Autoantibodies to specific enzymes or regulators of enzyme activity do possess specific disease associations. The titers or presence of these autoantibodies may predict morbidity or response to therapy. These autoantibodies may be detected by Western blotting, enzyme-linked immunosorbent assays, tissue immunofluorescence, radioimmunoassay, immunoprecipitation flow cytometry or inhibition of enzyme activity. For example, anti-pyruvate dehydrogenase inhibits the activity of purified enzyme, but not relatively intact mitochondrial preparations. Most evidence suggests that the production of autoantibodies to specific enzymes represents an epiphenomenon secondary to tissue damage rather than a primary event in the pathogenetic pathway.

Alkaline Phosphatase↗