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Biomedical subjects

L L Barton

Publications and source records attributed to L L Barton.

At least 127 records · Page 7Linked to original sources
PubMed1984

Childhood cervical adenitis.

Cervical lymphadenopathy is common in children. Although infectious adenitis is the most probable diagnosis, a large number of congenital and acquired, neoplastic and non-neoplastic lesions must also be considered. Evaluation of infectious cervical lymphadenitis should include a careful history and physical examination, followed by a tuberculin skin test and cultures of the throat and lymph node aspirate. The first therapeutic step is to prescribe a semisynthetic penicillinase-resistant penicillin, aimed at the most common bacterial organisms.

Anti-Bacterial Agents↗
PubMed1983

Nosocomial spread of Haemophilus influenzae type b infection documented by outer membrane protein subtype analysis.

This report provides evidence of nosocomial transmission of Haemophilus influenzae type b infection between two children in an acute care hospital. In the past, transmission of infection between these children would have gone unrecognized, because the isolates from the respective cases differed in susceptibility to ampicillin. However, the outer membrane protein profile of the two isolates was identical and has previously been observed in less than 2% of type b Haemophilus isolates from patients with invasive disease in the St. Louis area. Thus the likelihood is very low that these two children were both infected with this strain by chance alone (P less than 0.0004). From previous experience, the risk of transmission of Haemophilus in an acute care setting would appear to be very low. However, nosocomial transmission may occasionally occur.

Ampicillin↗
PubMed1983

Energy coupling to nitrite respiration in the sulfate-reducing bacterium Desulfovibrio gigas.

By use of a membrane fraction prepared from Desulfovibrio gigas grown in a lactate-sulfate medium, synthesis of ATP was demonstrated to be coupled to the oxidation of molecular hydrogen and reduction of either nitrite or hydroxylamine. This phosphorylation was uncoupled from electron transport by pentachlorophenol, methyl viologen, and gramicidin, but not by oligomycin. The extrusion of protons from the cells was shown to be coupled to the hydrogen-nitrite respiratory system, and, assuming the localization of nitrite reductase on the outer side of the plasma membrane, H+/2e- values of 2.0 +/- 0.3 were obtained. Energy coupling observed with this system appears to be due to electron transfer-coupled proton translocation rather than vectorial electron transfer associated with hydrogen oxidation.

Adenosine Triphosphate↗
PubMed1981

Reduction of circulating granulocytes induced by type 1 pneumococcal cell walls in New Zealand white rabbits.

Granulocytopenia seen during human pneumococcal disease is associated with a worsened prognosis. Streptococcus pneumoniae type 1 reduces circulating granulocytes and induces pulmonary leukostasis in rabbits. We studied which type 1 pneumococcal fraction(s) might be responsible for the reduction in circulating granulocytes. Rabbits were challenged intravenously with nonpyrogenic sterile saline, sonicated type 1 pneumococci, capsular polysaccharide from type 1 pneumococci, or cell walls from type 1 pneumococci. Nonviable pneumococci caused a mean decrease in blood granulocytes of 64% as compared with a mean increase of 124% in saline-injected controls, a difference significant at P less than 0.001. Pneumococcal cell walls induced significant decreases in circulating granulocytes at all doses tested when compared with saline-injected controls, whereas capsular polysaccharide induced no reduction in granulocytes. On a weight-for-weight basis, cell wall induced significantly more granulocyte reduction than did capsular polysaccharide at doses of either 10 mg (P less than 0.01) or 20 mg (P less than 0.005). A nonencapsulated pneumococcus also induced a profound granulocyte reduction (mean decrease in blood granulocytes, 88%) in the absence of detectable circulating polysaccharide. The cell wall fraction of S. pneumoniae type 1 was a more effective constituent in promoting the reduction in circulating granulocytes in rabbits.

Agranulocytosis↗
PubMed1979

Oxidative phosphorylation linked to the dissimilatory reduction of elemental sulphur by Desulfovibrio.

Hydrogenase and cytochrome c3 purified from Desulfovibrio gigas and D. desulfuricans strain Norway form a soluble complex which is capable of transferring electrons from molecular hydrogen to colloidal sulphur (S0). In this reaction, sulphur is reduced to hydrogen sulphide. Since both strains are capable of growth using elemental sulphur as terminal electron acceptor, it was of interest to check for oxidative phosphorylation in this sulphur reduction sytem. Membranes isolated from D. gigas or D. desulfuricans strain Norway contain hydrogenase and c-type cytochromes and catalyse the H2 leads to S0 reaction. With D. gigas, esterification of orthophosphate is coupled to the membrane-mediated transfer of electrons from H2 to S0. A P/2e ratio of 0.1 was observed and this value could be reduced by the addition of colloidal sulphur with c2 may be more than a purely chemical reaction. Since whole cells can use sulphur flower while cell-free extracts react only with colloidal sulphur, it is evident that cells handle sulphur in a way which is not yet fully understood.

Adenosine Triphosphate↗
PubMed1978

Energy-driven uptake of humic acids by Aspergillus niger.

The uptake of humic acids by mycelia of Aspergillus niger was demonstrated to be energy-dependent with a sensitivity to sodium azide and to 2,4-dinitrophenol. Greater uptake of humic acids by submerged mycelium occurred at pH 3.0 and at 32 degrees C. The rate of uptake was influenced by the concentration of humic acids with an apparent Km of 0.2 grams/ml and with a Vmax of 0.13 mg humic acids per gram mycelial dry weight.10 min-1. In the absence of added energy source, Vmax of 0.05 mg humic acids per gram mycelial dry wt.10 min-1 was obtained; however, the affinity for humic acids by this uptake system was the same as for the energy-driven process. Apparent binding of humic acids to cell structures was indicated because only 41.8% of the humic acids taken up by the energy-dependent system could be recovered.

Aspergillus niger↗