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N G Miller

Publications and source records attributed to N G Miller.

49 records · Page 3Linked to original sources
PubMed1979

Comparative study of the effect of thiabendazole and fungizone on Histoplasma capsulatum in macrophages.

The antifungal properties of Fungizone (amphotericin B intravenous solution) and thiabendazole on Histoplasma capsulatum within guinea pig macrophages were compared using the staining method and a newly developed plating method to determine the viability of intracellular H. capsulatum. The two methods were compared to determine the effectiveness of Fungizone and thiabendazole on H. capsulatum within macrophages. Fungizone was fungicidal for intracellular H. capsulatum, killing 99.9% of the yeasts at a concentration of 0.5 microgram/ml. There was some indication that non-viable intracellular yeasts were stained which could result in misinterpretation of the effectiveness of Fungizone using the staining method unless the yeasts are very closely examined for staining abnormalities. There was a good correlation between the two methods to demonstrate suppression of the multiplication of intracellular H. capsulatum in macrophages treated with 50 microgram/ml of thiabendazole. Thiabendazole was lethal for some intracellular H. capsulatum.

Amphotericin B↗
PubMed1978

Characterization of a Pasteurella multocida bacteriophage.

The Pasteurella multocida bacteriophage B939a produces turbid plaques, which suggests infection with a temperate phage. Attempts to induce production of lytic phage by UV irradiation were unsuccessful, however, Bateriophage B932a is highly stable at 4 C and relatively stable at room temperature. It tolerates moist heat at 60 C, but is inactivated at 70 C in 10 minutes. Morphologically, it is a tailed phage with a hexagonal head.

Bacteriophages↗
PubMed1976

Positional and species analysis of membrane phospholipids extracted from goldfish adapted to different environmental temperatures.

1. The proportion of ethanolamine phosphoglycerides in microsomal fractions of goldfish intestine increases at low environmental temperatures. The fatty acyl composition also changes, the proportion of C22:6 and C20:4 fatty acids increasing in positions 1 and 2 and position 2 respectively. The proportion of C16:0 and C18:0 fatty acids falls in position 1 and there is an apparent switch of C18:1 and C20:1 fatty acids from position 2 to position 1. 2. The proportion of choline phosphoglycerides does not depend on the previous environmental temperature of the fish. Temperature-dependent changes in fatty acyl composition in positions 1 and 2 take place in a way similar to that described for ethanolamine phosphoglycerides, but in this case C22:6 substitution is confined to position 2. 3. Choline phosphoglycerides have been further separated into 7 different molecular species. The amounts of species 3 to 7 increase and the amount of species 2 decreases at low adaptation temperature. These changes only account for part of total change in fatty acyl composition. The remaining changes occur by chain substitution within species. 4. Present results show temperature adaptation to be highly complex, involving both quantitative and qualitative changes in different phospholipids. The possible physiological significance of these changes are discussed together with the effects these changes might have on cholesterol-phospholipid interactions.

Acclimatization↗
PubMed1976

On the question of an electrokinetic requirement for phospholipase C action.

The phospholipase C of clostridium welchii (alpha toxin) has an absolute requirement for trace quantities of Ca2+. It attacks pure phosphatidylcholine particles (smectic mesophases) having a close-packed bilayer structure only when their surface zeta potential is made positive by the addition of certain divalent ions (e.g., Ca2+) to the aqueous phase or by the presence of low concentrations of long chain cations to the lipid. Alternatively, if the rotational freedom of individual phospholipid molecules is increased by the insertion of short n-alkanols (e.g., hexanol) into the bilayer or when a monolayer of the substrate at an air/water interface is expended, enzymic hydrolysis can occur without any requirement for a net postive charge on the surface.

Amines↗
PubMed1975

Recovery of Cryptococcus neoformans from sputum using new technics for the isolation of fungi from sputum.

Three sputum-digesting agents, N-acetyl-l-cytseine, dithiothreitol, and pancreatin-trypsin, were shown to be equally effective in allowing for the isolation of Cryptococcus neoformans from sputum samples in quantitative comparisons. By quantitative plating on bird-seed medium it was also shown the centrifugation after digestion concentrated C. neoformans into a platable sediment and, further, that the organisms, when present in concentrations as low as 10 yeasts per ml. of sputum, could be isolated with much higher frequencies than when no digestion-centrifugation procedure was used.

Acetylcysteine↗
PubMed1973

Cytotoxic factor in the blood and plasma of animals during leptospirosis.

Whole blood and plasma from animals in the acute stage of leptospirosis contained a toxic factor which produced a cytopathic effect on fibroblastic L cell monolayers. Firm adsorption of cytotoxic factor (CTF) to L cells occurred within 1 h. The highest titer of CTF in plasma was reached at 24 h and declined after 48 h after the inoculation of leptospires. Toxic effects were also obtained with intracerebral inoculation of mice with plasma containing CTF. Mice showed signs of motor instability and muscular spasms shortly after inoculation with CTF. Death usually occurred within 1 h.

Animals↗
PubMed1966

Growth of Leptospira pomona and Its Effect on Various Tissue Culture Systems.

Miller, Robert E. (University of Nebraska College of Medicine, Omaha), Norman G. Miller, and Roberta J. White. Growth of Leptospira pomona and its effect on various tissue culture systems. J. Bacteriol. 92:502-509. 1966.-Leptospira pomona strain 3341 was grown in association with primary fetal bovine kidney (PBK) and human embryonic skin-muscle fibroblastic (HE) cells in Eagle's minimal essential medium (MEM) with 5% sheep serum. Growth curves of leptospires in PBK and HE cell cultures showed no substantial increase in growth above that obtained in Eagle's MEM in the absence of tissue culture cells. This suggested that no stimulatory growth factors for leptospires were produced by the tissue cells. Fibroblastic cells of the PBK monolayer showed separation, deterioration, and, finally, complete disintegration. Epithelial-like cells remained unaffected. HE cells showed the same cytopathic effect as PBK fibroblastic cells, indicating that this effect was not limited to PBK fibroblastic cells. Warthin-Starry stains of PBK and HE cell monolayers showed masses of leptospires adhering to fibroblastic cells, whereas only a few were seen on epithelial-like cells. Large numbers of leptospires on the surface of fibroblastic cells are very likely associated with the cytopathic effect. Dislodgment of leptospires from fibroblastic cells did not increase the total number of spirochetes in the culture. This indicated that leptospiral growth did not occur on the surface of these cells.

Journal Article↗
PubMed1962

IN VIVO AND IN VITRO OBSERVATIONS OF LEPTOSPIRA POMONA BY ELECTRON MICROSCOPY.

Miller, Norman G. (University of Nebraska College of Medicine, Omaha) and Richard B. Wilson. In vivo and in vitro observations of Leptospira pomona by electron microscopy. J. Bacteriol. 84:569-576. 1962.-Leptospira pomona 3341 was observed by electron microscopy, after the preparation of thin sections from culture material and from infected hamster tissue. The external membrane of low electron density envelops the entire leptospire and appears to be quite flexible, as suggested by its many folds. The spiral protoplasmic body is tubular in structure with a relatively dense wall and a central area of low electron density. Occasionally, very dark circumscribed bodies were seen imbedded in the protoplasmic wall. Detailed morphology is presented of a knoblike structure located at the end of the axial filament. Bifurcation of the axial filament could be demonstrated in leptospires from cultures. Leptospires were observed free or enclosed in vesicles within the cytoplasm of liver parenchymal and renal tubule cells. Erythrocytes located in kidney tissue also contained leptospires within the cytoplasm. The appearance of intracellular leptospires is much the same as those seen extracellularly or from culture.

Journal Article↗