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Biomedical subjects

D H Shaw

Publications and source records attributed to D H Shaw.

At least 37 records · Page 2Linked to original sources
PubMed1986

The structure of the heptose-3-deoxy-D-mannooctulosonic-acid region in a mutant form of Aeromonas salmonicida lipopolysaccharide.

Lipopolysaccharide was isolated from a phage-selected mutant of a wild strain of Aeromonas salmonicida by the aqueous phenol method. The lipopolysaccharide consisted of the R form, containing per mole, three moles of L-glycero-D-manno-heptopyranose, one mole of 3-deoxy-D-manno-2-octulosonic acid (dOclA) and lipid A. The dOclA was not fully assayable by the thiobarbituric acid methods usually used, but its degradation product was detected, after Smith degradation of the lipopolysaccharide, either as free 3-deoxy-2-heptulosonic acid (after hydrolysis) or substituted by a mannopyranosyl residue derived from heptose. Mass spectrometry indicated that the dOclA existed in the furanose form and was substituted by the heptose trisaccharide through position six. Methylation analysis, chemical degradation, chromium trioxide oxidation and nuclear magnetic resonance spectroscopy were used to identify the structure of the core oligosaccharide as: L alpha DHepp(1----2)L alpha DHepp(1----3)L alpha DHepp(1----6)dOclAf(2----.

Acetylation↗
PubMed1985

Electrophoretic and immunochemical analyses of the lipopolysaccharides from various strains of Aeromonas hydrophila.

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis was used to analyze the lipopolysaccharides isolated from strains of Aeromonas hydrophila which exhibit virulence for fish and which autoaggregate during growth in static broth culture. The lipopolysaccharides contained O-polysaccharide chains of homogeneous chain length. Two of the strains produced a surface protein array, and immunofluorescence and phage-binding studies revealed that a number of these O-polysaccharide chains of homogeneous length traversed the protein array and were exposed on the cell surface. Immunochemical analyses by immunoblotting, enzyme-linked immunosorbent assay, immunofluorescence, and immunoprecipitation with both polyclonal and monoclonal antibodies revealed the presence of three epitopes on the polysaccharide moiety of this homogenous-chain-length lipopolysaccharide morphotype. One epitope was species serogroup specific and reactive by immunoblotting. This epitope was not present on the heterogeneous-chain-length O polysaccharides of nonautoaggregating strains of A. hydrophila examined. The second epitope was conformation dependent and cross-reactive with an epitope on the homogenous-chain-length O polysaccharides of Aeromonas salmonicida lipopolysaccharide. The third epitope was recognized by a monoclonal antibody and appeared to involve that region of the A. hydrophila and A. salmonicida lipopolysaccharide molecules which contained the O-polysaccharide-core oligosaccharide glycosidic linkage.

Adsorption↗
PubMed1984

Structure of the lipopolysaccharide core isolated from a human strain of Aeromonas hydrophila.

Lipopolysaccharide was isolated from the cell-walls of a human strain of Aeromonas hydrophila by the aqueous phenol method in 0.58% yield (based on dry weight of bacteria). The lipopolysaccharide consisted of SR-polysaccharide, core-oligosaccharide and lipid A; there was no O-specific polysaccharide. The core had the composition D-galactose, D-glucose, D-glycero-D-manno-heptose, L-glycero-D-manno-heptose and D-glucosamine in a molar ratio of 1:1:2:4:1. Glucosamine was linked to an L-glycero-D-manno-heptose residue by a bond which was resistant to hydrolysis. The D-glucosamine-(1----7)-LD-heptose disaccharide was isolated and identified by the mass spectrum of its methylated alditol and the heptose residue not observed under normal hydrolysis conditions was easily determined after deamination of the complete core. Methylation analysis, chemical degradation, periodate and chromium trioxide oxidations and nuclear magnetic resonance (13C and 1H NMR) spectroscopy were used to identify the structure of the core oligosaccharide as: (formula: see text)

Aeromonas↗
PubMed1984

Interaction of isoxicam with acetylsalicylic acid.

Ten healthy male volunteers were given 200 mg p.o. of isoxicam after an overnight fast and the plasma concentrations over time followed for 96 h by h.p.l.c. Five days later enteric coated acetylsalicylic acid (ASA) 650 mg four times daily was started and continued for 10 days producing steady state trough plasma salicylate of 83 mg/l (range 21-133). A second 200 mg isoxicam dose was given 5 days after starting ASA and the plasma concentration time-curve again followed. After ASA, there was no change in lag time (0.54 vs 0.51 h), time to peak concentration (10 vs 10 h), or disappearance t1/2 (28.7 vs 31.0 h) however the peak isoxicam concentration and AUC were reduced 18 and 22% respectively (P less than 0.01). Plasma protein binding of isoxicam studied by equilibrium dialysis was 96 +/- 1% in the absence and 86 +/- 5% in the presence of ASA. The reduction in binding was unrelated to plasma SA concentrations achieved or observed reductions in AUC for plasma isoxicam. ASA decreased plasma isoxicam binding, peak plasma isoxicam concentrations and AUC without altering the apparent disappearance half-life of total plasma isoxicam after a single oral dose.

Adult↗
PubMed1984

Structural and immunochemical homogeneity of Aeromonas salmonicida lipopolysaccharide.

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis was used to analyze the lipopolysaccharides of typical and atypical strains of the fish pathogen Aeromonas salmonicida. 32P intrinsically radiolabeled lipopolysaccharide in sarcosinate-extracted outer membrane preparations, lipopolysaccharide stained by silver in proteinase K-digested outer membrane preparations and whole cell lysates, as well as purified lipopolysaccharide, displayed O-polysaccharide chains which were unusually homogeneous with respect to chain length. Chemical analysis further revealed that the sugar composition of the smooth lipopolysaccharide purified from three typical strains was very similar. Immunoblotting and immunofluorescent staining with both polyclonal and monoclonal antibody showed that the O-polysaccharide chains were strongly immunogenic and were antigenically cross-reactive on typical and atypical strains from diverse origins. Immunofluorescence analysis and phage binding studies demonstrated that a number of these O-polysaccharide chains traversed the surface protein array of virulent strains of A. salmonicida and were exposed on the cell surface.

Aeromonas↗
PubMed1983

Hydrolytic release, and identification by g.l.c.-m.s., of 3-deoxy-D-manno-2-octulosonic acid in the lipopolysaccharides isolated from bacteria of the Vibrionaceae.

The identification of the peracetylated methyl glycosides of 3-deoxy-D-manno-2-octulosonic acid (KDO) methyl esters was achieved by g.l.c.-m.s. These peracetylated methyl glycoside methyl esters were obtained from fully acetylated lipopolysaccharides and core oligosaccharides of representative strains of the Vibrionaceae family by the following sequence of mild reactions: acetolysis, methanolysis, and acetylation. KDO was shown to be present in all of the lipopolysaccharides (LPS), a result in direct contrast to the generally accepted view of the absence of this compound in LPS from this family of bacteria.

Gas Chromatography-Mass Spectrometry↗
PubMed1983

Structural studies on the O-antigen of Aeromonas salmonicida.

Lipopolysaccharide from a strain of Aeromonas salmonicida salmonicida was isolated from cells by the aqueous phenol method in 2.3% yield (based on dry weight of bacteria). Hydrolysis of the lipopolysaccharide in 1% acetic acid afforded O-polysaccharide (19% by weight), core-oligosaccharide (12.2%) and lipid A (44.6%). Analysis indicated that 3-deoxy-D-manno-2-octulosonic acid was absent from the lipopolysaccharide and that no low-molecular-weight compounds were released by the mild hydrolysis. The O-polysaccharide had the monosaccharide composition of rhamnose, glucose and N-acetylmannosamine in molar ratio of 1.0:1.58:0.83. 75% of the N-acetylmannosamine residues were substituted at position 4 by O-acetyl groups. Hydrolysis of the methylated polysaccharide proved to be both difficult and dependent on the method of hydrolysis chosen, in all cases a partially methylated disaccharide of rhamnose and N-acetylmannosamine was identified in the hydrolysate. Methylation analysis, periodate oxidation and proton magnetic resonance analysis were used to confirm the structure of the repeating unit as: (formula; see text).

Aeromonas↗
PubMed1983

EEG sleep in outpatients with generalized anxiety: a preliminary comparison with depressed outpatients.

To develop further perspective on the psychophysiology of generalized anxiety disorder and primary depression, all-night electroencephalographic (EEG) sleep measures in outpatients with diagnoses of generalized anxiety disorder and primary (nondelusional) depression were compared. Both groups had difficulty initiating and maintaining sleep, and diminished amounts of slow-wave sleep. Compared to patients with generalized anxiety disorder, depressives had a shorter rapid eye movement (REM) latency, greater REM sleep percent and eye movement activity, and a different temporal distribution of REM sleep. Anxious patients showed few changes from first to second night, whereas depressives showed increases in several REM sleep indexes. The combination of REM sleep latency and REM percent correctly classified 86.7% of patients. These data may provide a more direct measure of central nervous system arousal and sleep/wake function than previous studies in the psychophysiology of anxiety. They also lend support to the clinical distinction between generalized anxiety disorder and primary depression and to the classification of anxiety states as disorders of initiating and maintaining sleep.

Adult↗
PubMed1983

A lipopolysaccharide-specific bacteriophage for Aeromonas salmonicida.

Cell wall lipopolysaccharide (LPS) was identified as the receptor for the Aeromonas salmonicida bacteriophage strain 55R-1. Mutants of A. salmonicida resistant to phage 55R-1 were unable to adsorb phage 55R-1 and were shown to be defective in LPS structure. Purified A. salmonicida LPS inactivated phage 55R-1, but the O-polysaccharide and the core oligosaccharide portions of the LPS were ineffective. These results suggest that lipid A was required for receptor activity. Antibodies directed against LPS also inhibited phage adsorption.

Aeromonas↗
PubMed1982

Application of automated REM analysis in depression.

Application of automated rapid-eye-movement (REM) analysis can characterize individual REM periods in depressed patients. Average REM count for the individual REM periods generally demonstrated considerable decreases in the second half of the REM period and differentiated patients who subsequently did not respond well to tricyclic antidepressants. These findings suggest that, even as late as six hours into a night of sleep, significant differences among depressed patients are present, based on treatment responder groups. Furthermore, a reevaluation of the previous emphasis on REM abnormalities in the first hour or two of the night may be indicated.

Adult↗
PubMed1982

Effects of electrosurgery on dog pulps under cervical metallic restorations.

Fifty-four Class V amalgam restorations were placed in nine beagle dogs to determine whether electrosurgical effects on pulp tissue could be altered by the presence of metallic restorations. An electrosurgical technique was performed, simulating clinical procedures for tissue removal while traversing the restorations. Time and power-use measurements were recorded for each operation. All operations that were performed within a time range imitating clinical procedures failed to produce changes in pulpal histology. When electrosurgical exposures were extended beyond 0.4 second contact with restorations, pulpal alterations occurred in the majority of specimens.

Animals↗
PubMed1982

Management of the dental patient receiving corticosteroid medications.

Patients who have undergone therapy with glucocorticoids present unique problems for the dentist. Persons currently receiving steroid therapy have altered responses to infection and wound healing. More important, many patients who are taking or have taken glucocorticoids have a high risk of developing acute adrenal insufficiency when placed in a stressful situation. When treating patients with a history of glucocorticoid therapy, one must obtain precise information from the medical history to determine the relative risk of pituitary-adrenal suppression. If the patient is at risk, the dentist must determine the need for the following prophylactic measures: (1) systemic antibiotic therapy, (2) anxiety control, and (3) increased administration of glucocorticoids (steroid prep). If a patient experiences adrenal crisis, the dentist must be capable of interpreting the signs and administering appropriate therapy.

Adrenal Cortex↗
PubMed1982

Electroencephalographic sleep findings in depressed outpatients.

We compared the electroencephalographic (EEG) sleep characteristics of 20 outpatients with those of 20 age-matched inpatients with major primary depressive disorders. Both groups showed similar patterns of sleep disturbance: reduced rapid eye movement (REM) sleep latencies, sleep efficiencies, and slow wave sleep. While the inpatients had greater REM activity in the first REM period than did the outpatients, both groups showed evidence of greater REM sleep time and REM activity during the first half of the night than do normals. The outpatients demonstrated a level of adaptation in that more REM sleep time and activity were present on night 2 than on night 1.

Adult↗