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Biomedical subjects

C E McCall

Publications and source records attributed to C E McCall.

At least 127 records · Page 7Linked to original sources

Stimulation of the hexose monophosphate shunt in human neutrophils by ascorbic acid: mechanism of action.

The addition of either ascorbic acid or dehydroascorbic acid to a suspension of polymorphonuclear leukocytes caused a dramatic increase in the resting hexose monophosphate shunt activity. A sequence of reactions involving dehydroascorbate, reduced glutathione, and reduced nicotinamide adenine dinucleotide phosphate is described to explain this stimulation. This sequence could provide an alternate method of producing H(2)O(2) and a bactericidal mechanism which is independent of myeloperoxidase.

Ascorbic Acid↗

Effect of catecholamines on the bactericidal activity of polymorphonuclear leukocytes.

Epinephrine, norepinephrine, and dihydroxyphenylalanine at 8 mm concentrations prevented iodination of zymosan by intact neutrophils and decarboxylation of l-alanine by leukocyte sonic extracts. The same concentration of epinephrine also reduced bactericidal activity of the leukocyte against Staphylococcus aureus, Enterobacter cloacae, and Proteus rettgeri without decreasing phagocytosis of bacteria. Spectral studies indicated that epinephrine interferes with the myeloperoxidase-mediated reactions by competing for available H(2)O(2) via its enzymatic oxidation to adrenochrome. These findings support a mechanism in which H(2)O(2) plays an important role in the bactericidal activity of the leukocyte.

Aldehydes↗

Nicotinamide adenine dinucleotide glycohydrolase activity in guinea pig polymorphonuclear leukocytes.

An enzyme is present in extracts of guinea pig polymorphonuclear leukocytes which can catalyze the hydrolysis of pyridine nucleotides. The enzyme is equally active toward nicotinamide adenine dinucleotide (NAD) or NAD phosphate, has an acid pH optimum, and is inhibited by either nicotinamide or isonicotinic acid hydrazide. This enzyme might be involved in the regulation of the pyridine nucleotide concentration within the leukocyte.

Albumins↗

Effect of methylprednisolone on some BCG-mediated changes in rabbit alveolar macrophage.

The effect of methylprednisolone sodium succinate treatment on Bacillus Calmette-Guérin (BCG) immunization was examined in alveolar macrophages of New Zealand White rabbits. Intravenous BCG injection caused a marked increase in cell number and in the hexosemonophosphate shunt activity. There was also a selective augmentation in the activity of acid phosphatase and beta-glucuronidase and an increase in lysosomal density. Activity of the lysosomal phospholipases was decreased. Steroid treatment suppressed the BCG-induced increase in cell number, hexosemonophosphate shunt activity, acid phosphatase, and beta-glucuronidase, and prevented the increase in lysosomal density. On the other hand, steroid treatment increased the activity of the phospholipases to levels higher than either control values or those obtained with cells from BCG-treated rabbits.

Acid Phosphatase↗

Complete deficiency of leukocyte glucose-6-phosphate dehydrogenase with defective bactericidal activity.

A 52 yr old Caucasian female (F. E.) had hemolytic anemia, a leukemoid reaction, and fatal sepsis due to Escherichia coli. Her leukocytes ingested bacteria normally but did not kill catalase positive Staphylococcus aureus, Escherichia coli, and Serratia marcescens. An H(2)O(2)-producing bacterium, Streptococcus faecalis, was killed normally. Granule myeloperoxidase, acid and alkaline phosphatase, and beta glucuronidase activities were normal, and these enzymes shifted normally to the phagocyte vacuole (light and electron microscopy). Intravacuolar reduction of nitroblue tetrazolium did not occur. Moreover, only minimal quantities of H(2)O(2) were generated, and the hexose monophosphate shunt (HMPS) was not stimulated during phagocytosis. These observations suggested the diagnosis of chronic granulomatous disease. However, in contrast to control and chronic granulomatous disease leukocytes, glucose-6-phosphate dehydrogenase activity was completely absent in F. E. leukocytes whereas NADH oxidase and NADPH oxidase activities were both normal. Unlike chronic granulomatous disease, methylene blue did not stimulate the hexose monophosphate shunt in F. E. cells. Thus, F. E. and chronic granulomatous disease leukocytes appear to share certain metabolic and bactericidal defects, but the metabolic basis of the abnormality differs. Chronic granulomatous disease cells lack oxidase activity which produces H(2)O(2); F. E. cells had normal levels of oxidase activity but failed to produce NADPH due to complete glucose-6-phosphate dehydrogenase deficiency. These data indicate that a complete absence of leukocyte glucose-6-phosphate dehydrogenase with defective hexose monophosphate shunt activity is associated with low H(2)O(2) production and inadequate bactericidal activity, and further suggest an important role for NADPH in the production of H(2)O(2) in human granulocytes.

Autoradiography↗

Characterization of an unusual strain of proteus rettgeri associated with an outbreak of nosocomial urinary-tract infection.

An outbreak of nosocomial urinary-tract infection was caused by a strain of Proteus rettgeri that fermented lactose overnight and was resistant to all antimicrobial drugs tested. The nonmotile isolates shared an O (somatic) antigen that differed from those of wild-type P. rettgeri. The organisms proved markedly serum-sensitive. In rats, the isolates elicited an acute interstitial nephritis with associated transient bacteriuria. Attempts to transfer the lac(+) trait and drug-resistance markers to recipient strains of Escherichia coli K-12 failed; exposure of the isolates to acridine orange yielded small numbers of non-lactose-fermenting variants which, however, were still as drug-resistant as before. Epidemiological studies failed to uncover the source of this unique strain and appeared to indicate exogenous spread of infection.

Acridines↗

Dissociation by colchicine of the hexose monophosphate shunt activation from the bactericidal activity of the leukocyte.

The effect of the in vitro addition of colchicine on various aspects of leukocyte metabolism was investigated. Colchicine in 6 mm concentration reduced the oxygen uptake of phagocytizing leukocytes to below the level of resting cells. A similar concentration of colchicine inhibited the increase in glucose-1-(14)C oxidation by 90% and the quantitative nitroblue tetrazolium reduction by about 50%. Experiments with broken cell preparations indicate that the inhibition of the hexose monophosphate shunt is due to an inhibition of the activity of the shunt enzymes glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. In spite of these pronounced metabolic changes, the addition of 6 mm colchicine had no observable effect on the bactericidal activity of the leukocyte against three test organisms. These results support a mechanism for phagocytosis in which the hexose monophosphate-shunt activation is a secondary phenomenon which is not required for the actual killing process.

Journal Article↗