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Biomedical subjects

P S Shirley

Publications and source records attributed to P S Shirley.

11 recordsLinked to original sources
PubMed1979

Dissociation of leukocyte alkaline phosphatase from the bactericidal activity of neutrophils.

We have identified an apparently healthy individual with no history of repeated infections whose neutrophils were virtually devoid of alkaline phosphatase activity by either spectrophotometric or histochemical assay. His cells showed normal bactericidal activity toward both Staphylococcus aureus and Escherichia coli when tested in vitro. We have also demonstrated that L-p-bromolevamisole, a potent inhibitor of alkaline phosphatase in many tissues, is likewise an effective inhibitor of the neutrophilic enzyme. Concentrations of this compound which caused nearly complete inhibition of the neutrophilic enzyme did not impair the ability of intact cells to kill bacteria. These results suggest that leukocyte alkaline phosphatase is not required for the normal bactericidal activity of neutrophils.

Alkaline Phosphatase↗
PubMed1978

Allosteric transformation of reduced nicotinamide adenine dinucleotide (phosphate) oxidase induced by phagocytosis in human polymorphonuclear leukocytes.

We used sensitive isotopic and fluorometric assay procedures to investigate reduced nicotinamide adenine dinucleotide (phosphate) [NAD(P)H]oxidation in a particulate fraction derived from normal and chronic granulomatous disease leukocytes. Granules isolated from normal resting cells showed allosteric kinetics with regard to oxidation of either NADH or NADPH, so that no enzyme activity was observed at physiological concentrations of substrate. If the granules were isolated from cells that had previously phagocytized zymosan, normal hyperbolic kinetics were obtained, so that activity could now be observed at low levels of substrate. The activity towards NADPH was always substantially greater than that towards NADH at any given concentration of substrate. This alteration in kinetics with phagocytosis was not observed with the other granule enzymes, acid phosphatase or beta-glucuronidase, and thus appeared to be specific for the reduced pyridine nucleotide oxidase(s). In contrast, granules isolated from cells of patients with chronic granulomatous disease showed allosteric kinetics regardless of whether they were obtained from resting or phagocytizing cells, so that NADPH oxidation was not measurable at physiological concentrations of substrate. This defect in the oxidation of NADPH by granules isolated from phagocytizing chronic granulomatous disease cells was observed over the pH range of 4.0 to 7.0. These data suggest that initiation of the respiratory burst by pahgocytosis normally requires an allosteric transformation in a reduced pyridine nucleotide oxidase, which in turn allows expression of enzymatic activity at physiological concentrations of substrate. The defect in chronic granulomatous disease appears to lie in an inability to achieve this transformation, and the enzyme remains in the inactive, allosteric form.

Acid Phosphatase↗
PubMed1978

Comparison of intracellular bactericidal activities of human neutrophils and eosinophils.

Eosinophils from a patient with hypereosinophilia were observed to phagocytize radiolabeled E. coli or S. aureus as effectively as neutrophils from a normal control. This was observed at a number of bacteria/cell ratios and a various time intervals following initial challenge and was confirmed by direct microscopic examination. In spite of comparables rates of phagocytosis, the eosinophils were consistently less capable of killing the bacteria. This correlates with an inability of eosinophil peroxidase to catalyze the peroxidase-H2O2-CI--mediated decarboxylation of amino acids; in contrast, both eosinophil and neutrophil peroxidases showed similar capabilities to iodinate protein in vitro. These data are compatible with the importance of the chloride-mediated mechanism in the bactericidal activity of intact phagocytes.

Blood Bactericidal Activity↗
PubMed1977

Deficiency of NADPH oxidase activity in chronic granulomatous disease.

NADPH oxidase activity was examined in paired 27,000 x g granule fractions isolated from normal polymorphonuclear leukocytes from patients with chronic granulomatous disease. At 0.17 mM NADPH, the oxidase activity was not measurable in normal resting cells but was activated by phagocytosis. This activation was absent in CGD cells. At higher levels of NADPH, activity was present in cells from patients with CGD, although it was lower than normal, and no difference in activity was found between resting and phagocytizing cells. Granule fractions from phagocytizing normal cells exhibited higher than granule fractions from resting normal cells at all levels of NADPH. These results suggest that NADPH oxidase activity is defective in chronic granulomatous disease, and further that the defect is not the absence of the enzyme but rather a failure to activate it.

Adolescent↗
PubMed1977

Effect of cyanide on NADPH oxidation by granules from human polymorphonuclear leukocytes.

Cyanide has been shown to stimulate both oxygen uptake and hexose monophosphate shunt activity in phagocytizing human polymorphonuclear leukocytes. It also stimulates the oxidation of NADPH by a particulate fraction derived from phagocytizing cells. This stimulation of NADPH oxidase is not observed in the presence of exogenous Mn2+. Studies with purified enzymes have shown that CN- also stimulates NADPH oxidation by horseradish peroxidase or lactoperoxidase, suggesting that the respiratory burst might be initiated by activation of a peroxidase-like enzyme in the human polymorphonuclear leukocyte. Based on studies of others, however, it does not appear as though the enzyme is identical to myeloperoxidase. The mechanism of the CN- stimulation appears to involve an oxidatic chain reaction, since it stimulates markedly NADPH oxidation in the presence of an artificial superoxide-generating system.

Cyanides↗
PubMed1975

Bactericidal activity of superoxide anion and of hydrogen peroxide: investigations employing dialuric acid, a superoxide-generating drug.

The addition of dialuric acid (a superoxide-generating drug) to a suspension of resting human neutrophils resulted in a stimulation of cellular hexose monophosphate shunt activity. Measurement of oxygen consumption demonstrated a rapid rate of oxygen uptake by the drug alone in aqueous solution. The subsequent addition of catalase (but not of superoxide dismutase) resulted in a substantial release of oxygen, indicating that H(2)O(2) was accumulating in the media. The generation of O(2) (-) by the drug was verified by measuring the rate of reduction of cytochrome c by the drug in the presence and absence of authentic superoxide dismutase. The growth of Escherichia coli B and Staphylococcus aureus was inhibited in vitro by addition of the drug to a suitable culture media; the degree of inhibition was dose dependent. This inhibition of bacterial growth could be completely reversed by the addition of as little as 5 mug of purified catalase, but was not affected by concentrations of superoxide dismutase that were 2,000-fold higher. These results suggest that the dialuric acid-induced stimulation of hexose monophosphate shunt activity in neutrophils is due to accumulated H(2)O(2). Further, the contribution of superoxide to the bactericidal activity towards E. coli and S. aureus is probably minimal compared with that of H(2)O(2).

Barbiturates↗