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Biomedical subjects

W L Gabler

Publications and source records attributed to W L Gabler.

At least 37 records · Page 2Linked to original sources
PubMed1989

Aggregated human colostral sIgA stimulates delayed, non-complement-dependent, NBT reduction by human neutrophils.

Antibodies often alert polymorphonuclear neutrophils (PMNs) to the presence of pathogens. In a study to learn if secretory immunoglobulins can carry out this function, we observed that as little as 4 micrograms/ml of secreted human immunoglobulin A from colostrum (sIgA), in the absence of antigen, stimulated human PMNs to reduce nitroblue tetrazolium (NBT). NBT reduction was inhibited 71% by superoxide dismutase. Active complement pathways were not required since comparable activity was obtained in the presence of heat-inactivated serum. Aggregated forms of sIgA were much more stimulatory than nonaggregated dimeric sIgA. Such interaction between PMNs and sIgA could act in situ to enhance protection against infections of exposed body sites or could initiate inflammatory tissue damage.

Complement Activation↗
PubMed1987

Inhibition of human neutrophil phagocytosis and intracellular killing of yeast cells by fluoride.

These processes depend upon the catabolism of glucose, which can be inhibited by fluoride (F-). We studied them with a radiolabelling technique using [3H]-uridine, which is incorporated into viable yeast cells, but hardly at all into neutrophils and dead or phagocytosed yeast cells. Lysis of neutrophils and treatment of the lysate with [3H]-uridine allowed estimation of intracellular killing of yeast cells. F- inhibited neutrophil phagocytosis and intracellular killing in a dose-related manner. Intracellular killing was significantly more sensitive to environmental F- than was phagocytosis. This effect on phagocytosis was not because of inhibition of opsonization of yeast, nor was it related to an effect on medium Ca2+.

Candida↗
PubMed1986

Role of extracellular calcium in neutrophil responsiveness to chemotactic tripeptides.

Cellular stores of Ca2+, but not extracellular Ca2+, are required for effective FMLP stimulation of neutrophil O2- production and degranulation. Neutrophils transferred from Ca2+-containing to Ca2+-free medium gradually lose their responsiveness to FMLP, such that after 40 min in the Ca2+-free environment they have lost 60-70% of their initial responsiveness to FMLP. The loss in responsiveness is reflected both in an increase in lag interval and decrease in velocity of O2-synthesis. The rate of decline in responsiveness to FMLP is greatly accelerated when neutrophils incubated in the presence of A23187 and Ca2+-free medium, while the rate of loss of responsiveness to FMLP is not affected by EGTA but the extent of loss is increased. Gradual recovery of FMLP-induced O2- generation occurs when cells are transferred from Ca2+-free to Ca2+-containing medium. PMA-induced neutrophil O2- generation is not influenced by the presence or absence of extracellular Ca2+. It is our view that the rise or fall of neutrophil responsiveness reflects repletion or depletion of cellular stores of Ca2+ essential for stimulus-effector coupling and that the role of extracellular Ca2+ is subservient to maintenance of these stores.

Calcimycin↗
PubMed1986

Modulation of the kinetics of induced neutrophil superoxide generation by fluoride.

Fluoride (F-) is unique in that, depending upon concentration, it can either stimulate or inhibit the synthesis of the neutrophil's major intracellular microbicidal product, superoxide anion (O2-). While a number of studies have delved into F- induction of O2- generation, little has been reported on the effect of F- on the synthesis of O2- induced by other agents. In this report, we show that F- inhibits the activation and activity of neutrophils induced either by formyl-methionyl-leucylphenylalanine (FMLP) or by phorbol myristate acetate (PMA). The extent of increase in lag period and decrease in velocity of O2- synthesis was found to be directly related to the concentrations of F- and of hydrogen ion in the medium and to the length of contact time between the neutrophil and F-. Decreasing the pH of the medium, while maintaining a constant concentration of F-, disproportionately increased the inhibitory effect of the anion over the effect of pH alone. Fluoride inhibited the responsiveness of neutrophils to FMLP more than it did their responsiveness to PMA. A gradual but partial reversal of F-'s inhibition of O2- synthesis could be achieved by transferring inhibited cells to F(-)-free medium. Our study shows that the suppression of both FMLP- and PMA-induced synthesis of O2- by neutrophils is most dramatic at a reduced pH and is probably related to the intracellular accumulation of F-.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium↗
PubMed1984

Activated rat neutrophils. A sequential quantitative assay for aggregation and NBT reduction.

We present here a rapid, sensitive, and convenient approach for the analysis of activated Lewis rat PMNs based on detecting separately, or in tandem, PMN aggregation and PMN reduction of nitroblue tetrazolium (NBT). These responses are quantitated using an ELISA scanner which can rapidly measure optical densities of cell cultures in microtiter plates. Aggregation induced by as little as 0.005 micrograms/ml of phorbol myristate acetate (PMA), 0.01 micrograms/ml lipopolysaccharide (LPS), or a 1:160 dilution of lymphokine-containing rat serum can be detected employing this approach. NBT reduction was induced by as little as 0.01 micrograms/ml PMA. Blocking studies employing 2-deoxyglucose, iodoacetamide, and polymyxin B gave the expected results and confirmed that these assays detect cellular responses to soluble stimuli. Using this technology the effects of PMA and LPS on rat peritoneal exudate PMNs were evaluated. Rat PMNs appeared less sensitive to LPS than human PMNs and also reduced NBT more slowly following stimulation with PMA. Because of the slowness in NBT reduction following stimulation, NBT reduction can be evaluated, in tandem, after measuring aggregation. The simplicity of this system, coupled with the speed with which large numbers of microcultures can be read and the low number of cells required, make this approach for studying responses especially attractive.

Animals↗
PubMed1983

Endogenous component chemotactic assay (ECCA).

We have developed a chemotactic assay in which migrated cells are quantitated by measuring levels of an endogenous cellular component. The endogenous component chemotactic assay (ECCA) employs standard double-membrane, blind-well methodologies but is unique in that leukocyte migration is quantitated by measuring lactic dehydrogenase (LDH) activity endogenous to cells that have migrated. This approach avoids the tedium of microscopic counting as well as the problems associated with cell-labeling techniques. Using the ECCA technique we have shown: (1) that N-formylmethionyl-leucyl-phenylalanine (fMLP) is both chemokinetic and chemotactic for human polymorphonuclear neutrophils (PMNs); (2) that both incubation time and starting PMN density affect the proportion of cells that migrate; (3) that approximately 30% of the available PMNs eventually migrate; and (4) that PMN "fall off" from membranes, readily detectable by this assay, is affected by starting PMN density, incubation period, and nature of the attractant. The technique as presented can detect migration when a starting cell density as low as 7 x 10(4) PMNs/well is employed and can be made more sensitive by increasing the period over which LDH is allowed to act. Considerable potential exists to further apply the ECCA concept to the study of the migration of subpopulations of cells in mixtures by assaying for distinguishing endogenous cellular markers.

Buffers↗
PubMed1982

A rapid quantitative assay for activated neutrophils.

We present here a rapid, sensitive, and convenient assay for activated human PMNs based on detecting the decreased optical density (OD) of aggregated cell suspensions. This quantitative assay uses an ELIZA machine to measure OD changes, with time, of activated cells (5 X 10(5) cells/well) in microtiter plates. The assay is sensitive, detecting aggregation induced by as little as 0.0001 microgram/ml of LPS, or lymphokines in Con-A-activated supernatant diluted 1/500. The assay permits analysis of 400 separate PMN suspensions on the same day starting with less than 80 ml of blood.

Cell Aggregation↗
PubMed1979

Fluoride inhibition of polymorphonuclear leukocytes.

Significant inhibition of PMN metabolic activity by F- occurred at 0.1, 0.5 and 0.0 mM F- for O2- generation, 1-C14 CO2 release labeled glucose and NBT-reduction respectively. This inhibition resulted primarily from F- suppression of nonoxidative glucose metabolism. As the concentration of F- in the O2- generating system increased beyond 10 mM, a rise in production of O2- anion occurred, peaking at 20 mM F-, followed by a rapid decline.

Carbon Dioxide↗