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Biomedical subjects

R B Bridges

Publications and source records attributed to R B Bridges.

32 records · Page 2Linked to original sources
PubMed1981

Complement levels in cigarette smokers: elevation of serum concentrations of C5, C9, and C1-inhibitor.

Serum levels of 13 individual complement component and control proteins were measured in 25 male cigarette smokers and 25 male non-smokers. A significant elevation of the mean serum levels of C5, C9 and C1-inhibitor was demonstrated for the smokers while levels of C1q, C2, C4, C3, C6, C8, Factor B, properdin, C3b inactivator and beta 1H did not differ significantly between the two groups. Serum level of C9 in individual smokers correlated significantly with both the present amount of consumption and cumulative consumption, while C5 level correlated with present consumption. The complement profile in the cigarette smoker is similar to that observed in certain inflammatory conditions. The elevation of C5, C9 and C1-inhibitor levels may reflect the presence of a low grade inflammatory process in the cigarette smoker.

Adolescent↗
PubMed1980

Effects of cigarette smoke and its constituents on the adherence of polymorphonuclear leukocytes.

The in vitro effects of the water-soluble fraction of whole cigarette smoke (WSF) and two alpha, beta-unsaturated aldehydes of cigarette smoke (acrolein and crotonaldehyde) on polymorphonuclear leukocyte (PMNL) adherence were determined with nylon fiber columns. Each of these cigarette smoke constituents caused a dose-dependent inhibition of PMNL adherence. However, at least fivefold higher concentrations of these agents were necessary to inhibit adherence as compared with those necessary to achieve the same level of inhibition of PMNL chemotaxis. Furthermore, inhibition of adherence by WSF could be differentiated from its effects on chemotaxis in that reduced glutathione completely protected chemotaxis from the effects of WSF but only afforded partial protection to PMNL adherence. These data suggest that the inhibitory effects of WSF, acrolein, and crotonaldehyde on PMNL chemotaxis are not due to their inhibition of adherence. Finally, although PMNL adherence is considered to be an integral part of the chemotactic mechanism, differentiation between these two PMNL functions may be possible, since some inhibitors of chemotaxis do not have corresponding inhibitory effects on adherence.

Acrolein↗
PubMed1977

Effects of tobacco smoke on chemotaxis and glucose metabolism of polymorphonuclear leukocytes.

The effect of tobacco smoke on in vitro chemotaxis of human polymorphonuclear leukocytes (PMN) was determined. Whole tobacco smoke, gas phase of smoke, and water-soluble fraction were potent inhibitors of PMN chemotaxis. The results indicated that PMN chemotaxis was inhibited in a dose-dependent manner by water-soluble fraction and that this suppression was not a result of cytotoxicity. In an attempt to determine the mechanism of chemotaxis inhibition, the effect of tobacco smoke on glucose metabolism of PMN was studied. Exposure of PMN to whole smoke, gas phase, or water-soluble fraction resulted in an increase (twofold) in glucose catabolism via both glycolysis and the hexose monophosphate shunt, with no apparent effects on the metabolism of glucose via the tricarboxylic acid cycle. These results suggest that the inhibitory effects of tobacco smoke on PMN chemotaxis were not directly attributable to effects on glucose metabolism of these cells. Further, the inhibitory effects of water-soluble fraction on PMN chemotaxis were shown to be largely irreversible and preventable in the presence of cysteine. Thus, the major inhibitory effects of tobacco smoke probably result from the direct action of oxidants and/or thiol-reactive substances on PMN.

Adult↗
PubMed1977

Effects of cigarette smoke components on in vitro chemotaxis of human polymorphonuclear leukocytes.

Some ciliostatic components of cigarette smoke were studied as inhibitors of in vitro chemotaxis of human polymorphonuclear leukocytes (PMNs). In comparison to their concentration in an inhibitory level of cigarette smoke, the unsaturated aldehydes acrolein and crotonaldehyde were the most potent inhibitors, whereas nicotine, cyanide, acetaldehyde, and furfural were the next strongest inhibitors. In contrast, sulfide, propionaldehyde, butyraldehyde, and the phenols (phenol and o-, m-, and p-cresol) were relatively weak inhibitors of PMN chemotaxis. Acrolein and crotonaldehyde mimicked whole cigarette smoke in their effects on PMNs by not causing loss of PMN viability, yet their effects were prevented by the addition of cysteine. On the other hand, addition of nicotine, cyanide, acetaldehyde, and furfural to PMN suspensions resulted in a limited loss of cellular viabilities, and their effects on PMNs were not prevented by cysteine. Of the tested components, only cyanide significantly altered PMN glucose metabolism by increasing carbon flow via the glycolytic and hexose monophosphate pathways in a manner similar to that observed with whole cigarette smoke. The results of this study suggest that the unsaturated aldehydes, including acrolein and crotonaldehyde, are major contributors to the inhibitory properties of cigarette smoke. The inhibitory effects of these unsaturated aldehydes are probably due to a direct interaction of these oxidants and/or thiol-alkylating agents with PMNs, yet the glucose metabolism of these cells is unaffected. One interpretation of these data is that PMN chemotaxis is dependent upon particular cellular proteins containing one or more essential thiol group(s) but that these proteins are unrelated to glucose metabolism.

Chemotaxis, Leukocyte↗
PubMed1975

Purification and properties of an NADP-specific 6-phosphogluconate dehydrogenase from Streptococcus faecalis.

A procedure is described for the purification of 6-phosphogluconate dehydrogenase (6-phospho-D-gluconate:NADP oxidoreductase (decarboxylating) EC 1.1.1.44) from cell extracts of Streptococcus gaecalis. A 180-fold purification was achieved with an over-all yield of about 12% and an average specific activity of 14. The enzyme was homogeneous as determined by polyacrylamide gel electrophoresis, immunoelectrophoresis, and sedimentation equilibrium, studies. Its weight average molecular weight, as measured by sedimentation equilibrium, was 108,000 +/- 3,600. Other methods employed for molecular weight determinations gave values that ranged between 106,000 and 115,000. An analysis of the enzyme by sodium dodecyl sulfate polyacrylamide gel electrophoresis showed it to be a dimer composed of subunits having equal molecular weight. The amino acid composition of the streptococcal enzyme is reported. The apparent Km values for NADP and 6-phosphogluconate were calculated from kinetic data and found to be 0.015 mM and 0.024 mM, respectively. Kinetic studies also indicated that the binding of one substrate did not affect the apparent affinity of the enzyme for the other substrate.

Amino Acids↗
PubMed1966

Changes in lipid composition of the maturing rat testis.

1. The lipids and fatty acids of the lipids of testes of rats aged 4 weeks to 6 months were separated and analysed. 2. A decrease in concentration of triglyceride was noted, but there was no significant change in the concentration of phospholipids, plasmalogen or cholesterol during this time. 3. There were no significant differences in the total lipid concentration of palmitic acid, stearic acid, linoleic acid, arachidonic acid and docosatetraenoic acid between the various age groups. 4. A decrease in the concentration of oleic acid in the phosphatide and triglyceride fractions and an increase in the concentration of docosapentaenoic acid (characterized as the Delta4,7,10,13,16-isomer) in phosphatides but not in triglyceride were observed during the maturation period. 5. Histological studies indicated that the lipid changes occurred at the same time as the appearance and maturation of the spermatids.

Animals↗