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Biomedical subjects

T H Pennington

Publications and source records attributed to T H Pennington.

At least 73 records · Page 4Linked to original sources
PubMed1989

Characterisation of methicillin-resistant isolates of Staphylococcus aureus by analysis of whole-cell and exported proteins.

Thirty-four isolates of methicillin-resistant Staphylococcus aureus (MRSA) from patients in Glasgow Royal Infirmary were studied. Whole-cell protein profiles obtained by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) were compared with banding patterns produced by immunoblots of exported proteins. Human plasma was used as a source of staphylococcal antibodies for the immunoblots. SDS-PAGE of whole-cell extracts did not usefully distinguish different isolates of MRSA. Reproducible banding patterns were obtained by immunoblots of exported proteins. Analyses of immunoblots by use of the Dice coefficient demonstrated that isolates of MRSA could be divided into two main groups. Immunoblots of exported proteins provided a rapid, reproducible and sensitive method for characterisation of MRSA.

Bacterial Proteins↗
PubMed1989

Characterization of coagulase-negative staphylococci by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot analyses.

Coagulase-negative staphylococci are important nosocomial pathogens. At present, no wholly satisfactory typing scheme exists for these organisms. Therefore, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting were assessed as characterization methods. A total of 100 type strains and nontyped isolates representing nine species of coagulase-negative staphylococci were analyzed. Each species had a reproducible, characteristic whole-cell banding pattern when analyzed by either method. These species-specific profiles were obtained for all isolates despite disparate geographical origins and clinical isolation sites. Intraspecies similarities, calculated by using the Dice coefficient, were significantly higher than interspecies similarities. Although some species were more heterogeneous than others, the allocation of isolates to any particular species was reinforced by the high degree of interspecies dissimilarity. Application of SDS-PAGE also distinguished discrete subspecies groups. These groups possessed the characteristic profile of their species but were distinguished by a group of variable polypeptides. Species-specific banding patterns were also obtained by immunoblotting of whole-cell polypeptides. Differences between immunoblot and SDS-PAGE profiles could be attributed to variations of antigenicity of particular polypeptides. However, both SDS-PAGE and immunoblotting provided reproducible and sensitive methods for characterization of coagulase-negative staphylococci. Standardization of these techniques could provide the basis for a primary typing scheme.

Bacterial Proteins↗
PubMed1989

Temporal study of staphylococcal species on the skin of human subjects in isolation and clonal analysis of Staphylococcus capitis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

The staphylococcal skin floras of an isolated group of subjects were studied for 1 year. A wide variation in isolation patterns was found for different species. Staphylococcus intermedius, previously thought to be of veterinary origin, was found to be part of the resident flora of some subjects, and this may indicate a wider role for it in clinical infection. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of S. capitis isolates indicated persistent skin colonization at some sites; each region was colonized by only one clone of that species, although an adjacent area could be inhabited by a separate clone. Nine clonal groups were identified by SDS-PAGE; there was a degree of specialization between the groups with regard to the sites which they colonized. The interaction between species at a single site was less well defined. Noncolonizing isolates often exhibited phenotypic similarities that were lower than expected when compared with their presumed source. The results of SDS-PAGE analysis were compared with immunoblotting, antibiograms, and biotyping, and SDS-PAGE analysis was found to be a useful and practical tool for epidemiological work.

Adult↗
PubMed1988

The Lister steam spray in Aberdeen.

A Lister 'steam spray producer' in the possession of Aberdeen University is described. The introduction of antiseptic surgery to Aberdeen by Alexander Ogston and the subsequent adoption of the spray and its enthusiastic use by him is recounted, with emphasis on the final years of its employment as part of the antiseptic ritual.

Antisepsis↗
PubMed1987

Haemophilus influenzae subtyping by SDS-PAGE of whole-cell polypeptides.

Strains of Haemophilus influenzae isolated from patients in N.E. Scotland between 1983 and 1986 have been subtyped by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of whole-cell polypeptides. Gels were stained with Coomassie blue and polypeptide profiles were analysed using the Dice coefficient of similarity. Type b strains were all closely related, the 19 strains analysed being grouped at a 90% similarity level into one large (13 strains) and one small (3 strains) cluster with 3 strains being ungrouped. Thirty-six non-typable, epidemiologically unrelated strains were subtyped; one pair of strains had indistinguishable polypeptide profiles. The polypeptide profiles of the remaining strains showed much heterogeneity, although groups of strains isolated from the same patient over short periods showed indistinguishable profiles.

Bacterial Proteins↗
PubMed1987

Staphylococcal whole-cell polypeptide analysis: evaluation as a taxonomic and typing tool.

Whole-cell-polypeptide profiles obtained by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) were used in conjunction with the API-Staph technique to identify different strains of Staphylococcus aureus, S. epidermidis, S. saprophyticus and S. capitis. Complete concordance of results from both techniques was achieved with all strains examined. Visual analysis of the polypeptide patterns and comparison by use of the coefficient of Dice showed minor differences in band pattern between strains of the same species but each species produced a pattern distinguishable from that of any other. The results suggest that although SDS-PAGE can be used to identify staphylococcal species, this type of analysis will not readily provide the basis for a typing method.

Bacterial Proteins↗
PubMed1987

Western blot analysis of staphylococcal antibodies present in human sera during health and disease.

IgG antibodies directed against Staphylococcus aureus were examined by Western blotting in sera from 15 healthy individuals isolated for a year in Antarctica. Sera reacted with many staphylococcal antigens in whole-cell extracts and individuals showed unique and unchanging blot profiles. The IgG and IgM profiles of patients with deep-seated staphylococcal infections were also examined by Western blotting. Anti-staphylococcal IgM antibodies that reacted with an antigen of apparent molecular mass 31 X 10(3) were present in all patients with staphylococcal disease, and were absent from, or detected in much smaller amounts in, control sera.

Antibodies, Bacterial↗
PubMed1984

The effect of monensin on virion production and protein secretion in pseudorabies virus-infected cells.

The effects of monensin on cells infected with pseudorabies virus have been studied. Treatment with monensin (1 microM) prevented the secretion of the 89K pseudorabies virus-induced sulphated glycoprotein. A polypeptide with a mol. wt. of 78K was secreted into the medium from monensin-treated BSC-1 cells. Mannose labelling showed that initial glycosylation proceeded normally in the presence of monensin, although the absence of fucose label revealed that the later stages in processing were blocked. No intracellular accumulation of virus-induced proteins was found in monensin-treated cells. Infectivity assays, measurement of thymidine-labelled particles and electron microscopy showed that monensin blocked the release of virus particles from cells, although viral morphogenesis was unaffected.

Animals↗
PubMed1982

Specific secretion of polypeptides from cells infected with myxoma virus.

The polypeptides secreted from cells infected with myxoma virus have been studied. Three virus-induced polypeptides were detected. One major and one minor polypeptide were synthesized and secreted in the absence of virus DNA synthesis; one minor polypeptide was not detected in the medium under such conditions. All these polypeptides were glycosylated and one was sulphated. Two precipitin lines were seen in Ouchterlony tests examining medium from infected rabbit cells and using serum from rabbits convalescent from myxoma virus infections. These antigens were unrelated to the virus-specific antigens released from cells infected with vaccinia virus. No major differences were detected in comparisons between the polypeptides secreted from cells infected with virulent and relatively avirulent strains of myxoma virus.

Animals↗
PubMed1979

Hepatitis Bs antibody in alcoholic cirrhosis.

Sera from patients with chronic liver disease were tested for antibody against hepatitis B surface antigen by radioimmunoassay. The antibody was found in 25% of patients with alcoholic cirrhosis and in 52% when alcoholic cirrhosis was associated with portal hypertension, these results being significantly higher than in a matched control population. Other forms of chronic liver disease did not differ from the control population. Hepatitis B virus infection might be a factor in determining which alcoholic patients go on to develop chronic liver disease and cirrhosis.

Antibodies, Viral↗
PubMed1978

Antigenic differences between strains of Newcastle disease virus.

Comparison of strains of Newcastle disease virus by kinetic neutralization tests and immunodiffusion tests (after virion disruption by ether and Tween 80) enabled antigenic differences to be demonstrated between four out of five strains tested. No correlation was demonstrated between the antigenic structure and virulence of these strains.

Antigens, Viral↗
PubMed1978

Protease activation of Sendai virus infectivity; studies in non-permissive and permissive cells.

Non-infectious virus particles are produced by BSC-1 cells after infection with Sendai virus. Trypsin treatment of these particles activates their infectivity. The studies reported here show that such non-infectious virus particles adsorb normally to cells but cannot initiate infection even after very long adsorption periods. Secondary Rhesus monkey kidney cells support the growth of Sendai virus but cannot activate the infectivity of virus grown in BSC-1 cells. The significance of these results is discussed.

Adsorption↗
PubMed1978

Specific secretion of polypeptides from cells infected with vaccinia virus.

The pattern of polypeptides specifically secreted by cells after infection with vaccinia virus has been analyzed. A complex pattern of apparently virus-specified polypeptides exhibiting temporal control of the type seen with intracellular polypeptides after virus infection was observed. Some of the specifically secreted polypeptides were shown to be modified by glycosylation and sulfation. The possible significance of these results is discussed.

Cell Line↗
PubMed1977

Processing of a pseudorabies virus-induced protein which is glycosylated, sulphated and excreted.

Cells infected with pseudorabies virus excrete large amounts of a glycosylated sulphated protein, mol. wt. 89000, into the extracellular fluid. This paper reports the results of studies on the processing of this protein. Glycosylation occurs during, or very soon after, synthesis of the polypeptide chain. After a delay of several minutes the glycoprotein is sulphated; inhibition of glycosylation by high concentrations of glucosamine does not interfere with this process. The glycosylated sulphated polypeptide is then reduced in size from mol. wt. 99000 to 89000, possibly by proteolytic cleavage, and is excreted. Inhibition of glycosylation does not interfere with the excretion of this polypeptide, which is an energy-requiring process.

Azides↗
PubMed1977

Isatin-beta-thiosemicarbazone causes premature cessation of vaccinia virus-induced late post-replicative polypeptide synthesis.

The effects of isatin-beta-thiosemicarbazone on vaccinia virus-induced polypeptide synthesis has been examined by polyacrylamide gel electrophoresis and autoradiography. The synthesis of pre-replicative and early post-replicative polypeptides proceeded normally in the presence of the drug; the onset of late post-replicative polypeptide synthesis occurred with normal timing under these conditions but the rate of synthesis of all virus polypeptides then declined rapidly.

Cell Line↗