Mesial temporal lobe epilepsy.
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to G M Schofield.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Two strains of Arachnia propionica and two Arachnia-like isolates were degraded by alkaline methanolysis and the non-hydroxylated fatty acid esters released were examined by thin-layer and gas chromatography. The fatty acid profiles obtained were both qualitatively and quantitatively similar and were comprised of iso-, anteiso- and straight chain saturated fatty acids with 13-methyltetradecanoic acid (i-15) and 12-methyltetradecanoic acid (ai-15) as major components. One of the Arachnia-like strains (HIK 288) had, in addition to i-15 and ai-15, major amounts of pentadecanoic acid (15:0). All of the strains gave characteristic polar lipid patterns consisting of diphosphatidylglycerol, phosphatidylglycerol and two incompletely characterised glycolipids. Analyses of wall amino acid preparations by gas and thin-layer chromatography showed that Arachnia propionica strains contain major amounts of alanine, glycine, glutamic acid and LL-diaminopimelic acid. The chemical data support the integrity of Arachnia propionica and provide a valuable means of differentiating it from morphologically and physiologically similar strains of Actinomyces israelii.
A model hot water distribution network was seeded with a virulent strain of Legionella pneumophila serotype 1. Ten weeks after inoculation, components of the system, which include aluminium discs, copper, stainless steel, silicone tubing, rubber and glass beads, were examined for colonization by L. pneumophila. The samples were stained with fluorescein-labelled antibodies to the strain and were examined with scanning electron microscopy. Colonization, which was accompanied by copious quantities of a slime-like debris, was heaviest on the rubber and least on the copper. Adherence to silicone tubing and stainless steel was observed.
Tap water, from an experimental hot water system, containing a known virulent strain of Legionella pneumophila was stored in screw-capped bottles for 14 months. Viable counts showed survival of L. pneumophila and at least three other bacterial species. This reinforces the view that L. pneumophila can survive in stagnant water for relatively long periods of time.
Simultaneous experiments were performed with sterilized and non-sterile water and an artificial hard water. After seeding with an environmental isolate of Legionella pneumophila numbers in the sterile and hard water decreased rapidly and colonization of various tap washer fittings failed to take place. Adhesion and growth of an environmental isolate of L. pneumophila to washers in non-sterile tap water was followed over a 4-month period with fluorescein-labelled antibody and by scanning electron microscopy. After adherence the individual cells appeared to divide to form chains which spread over the surfaces. Organisms other than legionellas were also present and a complex colonization matt was formed which was embedded in a protective coat of slime and debris. The numbers of L. pneumophila recovered from the water were highest between 4 and 7 weeks but they could still be cultivated after 4 months.
A virulent strain of Legionella pneumophila was inoculated into an enclosed system supplied with unsterilized water from a domestic hot water supply. Growth of bacteria was monitored over 10 weeks. An increase in the number of organisms other than legionellas occurred but few amoebae were observed and none could be cultured. Viable counts of L. pneumophila in the circulation fluid decreased slightly. However, particles of debris which accumulated in the apparatus and which were stained by the indirect fluorescent antibody technique were found to be almost totally composed of L. pneumophila. On dismantling the apparatus Legionella was isolated in moderately high numbers from several different types of surfaces, particularly natural rubber and silicone.
'Corynebacterium haemolyticum' (MacLean, Liebow & Rosenberg) differs to such an extent from the type species of Corynebacterium, C. diphtheriae (Lehmann & Neumann), that it should be removed from this genus. Chemical and numerical phenetic data indicate that 'C. haemolyticum' is a distinct taxon worthy of generic status. A new genus, Arcanobacterium, is described for the species A. haemolyticum (MacLean, Liebow & Rosenberg) nov.rev., comb.nov. The genus is tentatively placed within the 'coryneform group of bacteria'. The type species of the genus is Arcanobacterium haemolyticum and the type strain is ATCC 9345.
Two hundred and twenty-two representatives of the Actinomycetaceae and related taxa, including reference cultures, received strains and fresh isolates, were tested using 124 unit characters. The data were examined using numerical taxonomic techniques with various coefficients and average linkage clustering; the variation in composition of the clusters obtained from the different coefficients was slight. Most species included in the study formed discrete phena, which exhibited good differential characters. Actinomyces israelii was particularly well-defined and A. naeslundii and A. viscosus, although grouping together, did show divergence in several test results. Actinomyces bovis was initially linked with representatives of genera other than Actinomyces, these being Bifidobacterium, Corynebacterium pyogenes and Erysipelothrix rhusiopathiae. The strains of Bacterionema matruchotii and Rothia dentocariosa formed tight distinct clusters associated only at low similarity levels with other members of the family Actinomycetaceae. The Arachnia propionica phenon, although well-defined, appeared to consist of two subclusters which could be assigned to serotypes 1 and 2. Tests which may be useful in identification are tabulated and the relationships between the various taxa are discussed.
In spite of considerable advances during the last years, classification and identification of Actinomycetaceae and Propionibacteriaceae still present major problems. Uncertainties about the systematic position and taxonomic status of several genera and species, the lack of reliable distinguishing characteristics or use of inadequately adapted techniques of investigation interfere with both micribiological and clinical research and also with routine work in the diagnostic laboratory. Nevertheless, besides actinomycosis, an etiologically well defined suppurative infection, several other diseases and lesions such as lacrimal canaliculitis, caries and periodontal disease, inflammation following use of intrauterine pessaries, various types of abscess, septicaemia, and acne vulgaris have been attributed to the direct or indirect pathogenic effects of fermentative actinomycetes, propionibacteria, or eubacteria. Many questions concerning their individual pathogenicity and their pathomechanisms still remain to be answered, however.
96 strains of facultatively anaerobic actinomycetes and 2 Propionibacterium acnes strains were studied for their ability to deaminate and/or decarboxylate 13 amino acids, to reduce nitrate and nitrite, and to produce indole, using specially adapted micro-methods. Several of the tests performed were found to provide information which may aid in improving the classification and in facilitating the identification of these organisms.