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Biomedical subjects

K Moore

Publications and source records attributed to K Moore.

At least 253 records · Page 14Linked to original sources
PubMed1982

Evaluation of a colorimetric method for canine glycosylated hemoglobin.

Glycosylated hemoglobins can be used to monitor glucose status and the effectiveness of insulin therapy in canine diabetes mellitus. We have compared a colorimetric method with a time-consuming chromatographic method for measuring glycosylated hemoglobins in canine blood. Although the colorimetric method is sensitive to hemoglobin concentration, its convenience and sample size make it a possible alternative to other methods.

Anemia, Hemolytic↗
PubMed1980

The activation state of macrophage subpopulations from a murine fibrosarcoma.

We have separated subpopulations of macrophages from an immunogenic fibrosarcoma by the technique of unit gravity velocity sedimentation. The activation state of these subpopulations was determined by measurement of the Fc receptor avidity of adherent cells, and by their 5' nucleotidase and acid phosphatase activity. The subpopulations were compared to resident peritoneal macrophages and the peritoneal macrophage subpopulations elicited by injection of proteose peptone or C. parvum. The results show that two macrophage subpopulations exist within the tumour. The smaller, peroxidase-positive population, with a sedimentation velocity of 1-5 mm/h, is similar to proteose peptone stimulated macrophages with respect to Fc receptor expression, while the other, rapidly sedimenting population (5-9 mm/h) is partially activated. However, neither population achieved the level of activation demonstrated by rapidly sedimenting, C. parvum-activated macrophages. Analysis of the enzyme activity of rapidly adherent macrophages indicated that tumour, proteose peptone or C. parvum macrophages were all activated when compared to resident peritoneal macrophages. No significant differences were found with respect to the elevated levels of acid phosphatase in the three activated macrophage populations, but the 5' nucleotidase activity of C, parvum-elicited macrophages was significantly lower than either the proteose peptone or tumour macrophages. This again demonstrated that the tumour macrophages were less activated than C. parvum macrophages. These data show that tumour-infiltrating macrophages are a heterogeneous population composed of at least two subpopulations existing in different activation states and that within the tumour microenvironment they are not capable of differentiating to the higher activation state, demonstrated by C. parvum macrophages.

Acid Phosphatase↗
PubMed1980

Erythrocyte gamma-glutamylcysteine synthetase from normal and low-glutathione sheep.

gamma-Glutamylcysteine synthetase (L-glutamate:L-cysteine gamma-ligase (ADP-forming), EC 6.3.2.2) was purified from the erythrocytes of normal and low-glutathione sheep. The molecular weight (78 000), pH optimum (pH 7), substrate specificity, inhibition constant for glutathione (0.44-0.50 mM), electrophoretic mobility, and heat stability were similar for the purified enzyme from both sources. Using immunological techniques, the specific activity of gamma-glutamylcysteine synthetase from low-glutathione sheep was lower than that from normal sheep.

Animals↗
PubMed1980

Regulation of gamma-glutamylcysteine utilization in erythrocytes.

Glutathione is synthesized from gamma-glutamylcysteine and glycine via the action of glutathione synthetase. It is known that gamma-glutamylcyclotransferase is present in many cells and may convert gamma-glutamylcysteine to 5-oxoproline and cysteine, but until now there has not been a credible explanation for the apparent suppression of the gamma-glutamylcyclotransferase reaction during glutathione synthesis. Our data suggest that the gamma-glutamylcyclotransferase and glutathione synthetase pathways are regulated by a simple kinetic mechanism that favors the synthesis of glutathione.

Cysteine↗
PubMed1980

In vivo and in vitro turnover of spectrin phosphate in erythrocytes.

Erythrocyte deformability may be modulated by regulatory phosphorylation of spectrin. Most investigators have assumed that the phosphate attached to spectrin turns over in vivo. We tested that assumption using dog erythrocytes. Erythrocytes were labeled in vitro with solutions containing 32P. After 1 week at 4 degrees C, 60% of the 32P had been incorporated into the erythrocytes, the erythrocytic gamma-32P-ATP had a specific activity of 0.285 muCi/mumol (S.E. = 0.0138), and a membrane extract enriched in spectrin had 15,200 +/- 2390 cpm/mg of protein. When these erythrocytes were labeled with 51Cr, washed with saline, and infused autologously, they had a normal lifespan (t1/2 = 24.9 +/- 1.24 days). The gamma-32P-ATP disappeared exponentially, with a t1/2 of 7.84 +/- 0.506 hr. The radioactivity in low-ionic-strength membrane extracts and Triton X-100 pellets declined exponentially, with a t1/2 of 33.4 +/- 0.336 and 39.1 +/- 0.806 hr, respectively. When 32P-labeled erythrocytes were incubated in vitro in a 15 mM phosphate buffer, the gamma-32P-ATP (t1/2 = 3.97 hr) and the radioactivity of low-ionic-strength extracts (t1/2 = 4.18 hr) and Triton pellets (t1/2 = 4.54 hr) declined rapidly. These rates of spectrin phosphorylation-dephosphorylation suggest that this process may be physiologically important and that in vitro turnover rates are significantly higher than those observed in vivo.

Animals↗
PubMed1979

Systemic and in-situ natural killer activity in tumour-bearing rats.

Single-cell suspensions prepared by enzymatic disaggregation of an immunogenic 3-methylcholanthrene-induced sarcoma (Mc40A) contain a significant proportion of infiltrating leucocytes (approximately 42%), comprising T lymphocytes, macrophages and non-phagocytic FcR+ lymphoid-like cells. Tumour-infiltrating lymphocytes (TIL) were isolated and purified by successive passage over Sephadex G-10 columns and their cytotoxic activity in vitro compared with that of lymphoid cells from normal rats and from tumour-bearers at different times after implantation. For this purpose, surviving target cells were quantified by incorporation of the gamma-emitting analogue of methionine, 75Sel-methionine, in a 48-h assay which detected both cytotoxic and cytostatic effects. The reactivity of TIL, which was consistently demonstrable from 11 days after tumour transplantation, was essentially similar to that of normal splenic lymphocytes in magnitude and specificity. Reciprocal cytotoxicity tests using TIL and cultured targets from an antigenically unrelated tumour of similar aetiology (Mc57) showed that the manifestation of TIL cytotoxicity was determined, not by the tumour of origin, but by the susceptibility of the target cells. Evidence that the effector function of TIL was mediated in part by natural killer (NK) cells was derived from concurrent experiments using human myeloid cells (K562) as targets in an 18h 51Cr-release assay. In this system the level of NK activity was critically dependent on the numbers of tumour cells in the TIL population; contamination in excess of 2% gave rise to dose-dependent inhibition of NK function. The results show that within a progressively growing tumour known to possess rejection antigens, NK reactivity was detected in the absence of a demonstrable tumour-specific cytotoxic component.

Animals↗
PubMed1978

A simple method to determine gammaglutamyl-cyclotransferase activity in erythrocytes.

A new method for the determination of erythrocyte gammaGCT is described. The method follows the release of alanine from gammaglutamyl alanine by a series of linked reactions that result in the oxidation of NADH to NAD. The pH optimum for human erythrocyte gammaGCT was found to be 9.0, and the Km for gammaglutamyl alanine was found to be 2.3 X 10(-3) M. Human erythrocytes had the highest activity of all the species studied (human, rabbit, dog, sheep, cattle, chicken).

Animals↗
PubMed1978

Congenital nonspherocytic hemolytic anemia with an unstable hexokinase variant.

We report a family with a new hexokinase variant that gives rise to nonspherocytic hemolytic anemia in one apparently homozygous family member. The variant enzyme has a normal pH optimum, normal reaction kinetics, and normal electrophoretic properties, but has reduced activity and is apparently inactivated rapidly as the affected erythrocytes age.

Anemia, Hemolytic, Congenital Nonspherocytic↗