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Biomedical subjects

W H Chambers

Publications and source records attributed to W H Chambers.

68 records · Page 4Linked to original sources
PubMed1984

Effect of bacterial lipopolysaccharide on bovine polymorphonuclear neutrophil migration in vitro.

The in vitro effects of Escherichia coli 026:B6 lipopolysaccharide (LPS) on random migration of bovine polymorphonuclear neutrophils (PMN) was investigated. Treatment of peripheral blood leukocytes (PBL) with LPS significantly inhibited PMN migration. These inhibitions were observed at a threshold concentration of 5.0 micrograms/2.0 X 10(6) PBL. PMN migration inhibition was eliminated in PBL by the addition of polymyxin B, which binds the Lipid A moiety of LPS. Treatment of isolated PMNs with LPS significantly enhanced migration. Enhanced migrations were observed at threshold concentration of 2.5 micrograms/4.0 X 10(6) PMN. Collectively these findings indicate that the inhibition was caused by leukocyte inhibitory factor (LIF) production in PBL cultures, whereas enhancement was probably caused by PMN activation. These results provide further insight into the effects of LPS on in vitro bovine PMN migration by its distinct actions on different cells of PBL.

Animals↗
PubMed1983

Isolation of bovine polymorphonuclear leukocytes by density gradient centrifugation.

A method for the isolation of an enriched population (greater than 95%) of bovine polymorphonuclear leukocytes (PMNs) was developed using density gradient centrifugation. Leukocytes were isolated from peripheral blood by centrifugation in a density gradient medium (Percoll) of specific gravity 1.092. Viability was greater than or equal to 95% and the isolated PMNs were functional in migration inhibition and chemiluminescence assays. This has proved to be a simple effective method for obtaining bovine PMNs and yields cell populations that can be utilized for a variety of measures of PMN function.

Animals↗
PubMed1983

Direct bovine leukocyte migration inhibition assay: standardization and comparison with skin testing.

A direct leukocyte migration inhibition (LMI) assay under agarose was standardized for use in cattle. The procedure included maintenance of culture conditions at pH 7.4 in a humidified, 39 C incubator with 98% air and 2% CO2. Optimum demonstration of incubation was obtained using a 9-hour incubation period. The LMI assay was used to detect reactivity to keyhold limpet hemocyanin (KLH) and horseshoe crab hemocyanin (HCH). Calves sensitized to KLH had specific reactivity for KLH and occasional reactivity for HCH. Similarly, calves sensitized to HCH showed reactivity for HCH and occasional reactivity for KLH. The nonspecific reactivity in the LMI was more frequent after skin testing with both antigens. Specific association of LMI reactivity and DTH reactivity was found in 8 of 10 animals. There were no nonspecific skin test responses. The results suggest that consecutive LMI assays are required to establish trends in reactivity and these should be used in conjunction with other in vitro assays of cellular immune reactivity.

Animals↗
PubMed1975

Synthesis and antibacterial activities of some chloro analogs of 3 amino-3,4-dihydro-1-hydroxycarbostyril.

The effects of a chloro substituent upon the microbiological activities of 3-amino-3,4-dihydro-1-hydroxycarbostyril were determined. The 5-, 6-, and 7-chloro analogs were synthesized by reductive cyclizations of the appropriately chloro-substituted o-nitrophenylalanines, while the 8-chloro analog was obtained from the N-trifluoroacetyl-3-chloro-2-nitrophenylalanine ethyl ester. All of these compounds were observed to inhibit the growth of Escherichia coli 9723, Leuconostoc dextranicum 8086, and Lactobacillus plantarum 8014. The relative inhibitory activities of the chloro analogs were 7-Cl greater than 6-Cl greater than 8-Cl greater than 5-Cl in E. coli and 7-Cl greater than 6-Cl greater than 8-Cl = 5-Cl in L. dextranicum and L. plantarum. In each of the three microorganisms, the 7-Cl analog was a more effective growth inhibitor than the parent unsubstituted compound. The growth inhibitory activities of this class of compounds were demonstrated to be much more effective than those of the four corresponding lactams, the 5-, 6-, 7-, and 8-chloro analogs of 3-amino-3,4-dihydrocarbostyril.

Anti-Bacterial Agents↗
PubMedDate not supplied

Expression and function of Fc gamma RII on human natural killer cells.

In this report, we present data on the expression and function of Fc gamma RII (CD32) by natural killer (NK) cells. Highly enriched NK cell populations were isolated from peripheral blood lymphocytes by negative selection and consisted of > or = 95% CD3-/CD56+ cells. Flow cytometric analyses with anti-CD32 monoclonal antibodies (mAbs) demonstrated that a small proportion of NK cells were recognized by mAbs IV.3 and 41H16. Two-color flow cytometric analysis indicated coexpression of the epitope on NK cells recognized by both these mAbs. Verification of expression of CD32 on NK cells was obtained by demonstrating coexpression of CD32 on either CD16+ or CD56+ cells. The CD32+/CD16+ and CD32+/CD56+ cells represented approximately 7 and 3% of the total, respectively. CD32 transcripts were identified from highly purified NK cells using reverse transcription-polymerase chain reaction with CD32-specific primers, followed by Southern blotting. Enhanced chemiluminescence-Western blot (ECL-WB) analysis of lysates of purified NK cells indicated that mAb IV.3 recognized a molecule of approximately 40 kD. The Fc gamma RII on NK cells was able to transduce intracellular signals in several types of assay. Cross-linking of anti-CD32 resulted in a mobilization of intracellular Ca2+, although to a lesser extent than that induced by cross-linking CD16. Both mAbs IV.3 and 41H16 were found to be capable of inducing reverse antibody-dependent cellular cytotoxicity against FcR+ target cells (e.g. P815). These data represent the first direct description of the expression and function of Fc gamma RII on human NK cells.

Antibodies, Monoclonal↗
PubMedDate not supplied

NKR-P1dim/TCR alpha beta + T cells and natural killer cells share expression of NKR-P1A and NKR-P1D.

Natural killer (NK) cells and a T cell subset express NKR-P1s; however, it is not known if NKR-P1s on these cells are homologous. By molecular and biochemical means, we determined that NKR-P1s on NK cells and T cells were similar. Also, sequencing of polymerase chain reaction products derived from these populations indicated expression of a novel form, termed NKR-P1D, with approximately 60% nucleotide homology to NKR-P1A. NKR-P1D shares approximately 50% amino acid homology, overall and in the carbohydrate recognition domain, with rat NKR-P1A and mouse NKR-P1A -B, and -C. Transcripts for NKR-P1A (1.1 kb) and NKR-P1D (2.0 kb) were produced by NK cells and NKR-P1dim/TCR alpha beta + T cells. Some NK cell clones coexpressed NKR-P1A and NKR-P1D. However, other clones lacking NKR-P1A produced message for NKR-P1D.

Amino Acid Sequence↗