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Biomedical subjects

I Olsen

Publications and source records attributed to I Olsen.

At least 163 records · Page 9Linked to original sources
PubMed1990

Multivariate analysis of quantitative chemical and enzymic characterization data in classification of Actinobacillus, Haemophilus and Pasteurella spp.

Chemotaxonomic data for strains of Actinobacillus, Haemophilus and Pasteurella spp. were analysed using three multivariate statistical strategies: principal components, partial least squares discriminant, and soft independent modelling of class analogy. The species comprised Actinobacillus actinomycetemcomitans. Haemophilus aphrophilus, H. paraphrophilus, H. influenzae, Pasteurella multocida, P. haemolytica and P. ureae. Strains were characterized by cell sugar and fatty acid composition, lysis kinetics during EDTA and EDTA plus lysozyme treatment, and methylene blue reduction. In total 23 quantitative variables were compiled from chemotaxonomic analyses of 25 strains. A. actinomycetemcomitans and H. aphrophilus formed distinct classes which differed from those of H. paraphrophilus, H. influenzae and Pasteurella spp. All characterization variables, except those describing fatty acid content, contributed significantly to inter-species discrimination.

Actinobacillus↗
PubMed1990

Outer membrane proteins of Actinobacillus actinomycetemcomitans and Haemophilus aphrophilus studied by SDS-PAGE and immunoblotting.

This investigation characterized and compared outer membrane proteins (OMP) of the closely related Actinobacillus actinomycetemcomitans and Haemophilus aphrophilus by means of SDS-PAGE patterns and reactions on immunoblots with rabbit antiserum against A. actinomycetemcomitans FDC Y4. Reactions with serum from a patient with Papillon Lefévre syndrome (PLS), from whom periodontal wild strains of A. actinomycetemcomitans had been isolated, were also studied. OMP were purified with selective solubilization from lyophilized cells of 10 wild and 4 reference strains of A. actinomycetemcomitans and 4 reference strains of H. aphrophilus. OMP profiles from wild and reference strains of A. actinomycetemcomitans were similar while those from A. actinomycetemcomitans and H. aphrophilus differed. The most prominent difference was absence of a heat modifiable protein in H. aphrophilus strains. Immunoblotting revealed strong common antigens in most strains, including a heat modifiable protein with mol wt 34 kDa, as well as a 29 kDa and a 16.5 kDa protein. Treatment with pronase and sodium periodate confirmed the protein nature of the major OMP antigens.

Actinobacillus↗
PubMed1990

Three-dimensional structure of the surface layer of Wolinella recta.

The three-dimensional structure of the crystalline surface layer (S-layer) of Wolinella recta ATCC 33238T, a gram-negative, anaerobic periodontopathogen, was determined to 3.8 nm resolution by electron microscopy and digital image processing. The S-layer protein is closely associated with the outer bacterial membrane, and shows p6 symmetry with lattice spacing and thickness of 21 nm and 15 nm, respectively. The funnel-shaped subunits consist of 6 heavy domains located round a common base at the sixfold axis, and communicate with the adjacent subunits through a lighter domain at the threefold axis (M6C3 arrangement).

Bacterial Outer Membrane Proteins↗
PubMed1990

Nucleic acid probes as potential tools in oral microbial epidemiology.

The present review deals with genetic tools in the microbial diagnostic laboratory, types of nucleic acid probes, their construction and cloning, hybridization reactions, their sensitivity and specificity, and their advantages and limitations. The nucleic acid probes seem to possess a number of advantages over traditional diagnostic methods. DNA, RNA, and oligonucleotide probes are expected to have increased impact on our understanding of the pathogenesis and the treatment of infectious inflammatory periodontal diseases. In addition, these probes have potential application in epidemiological studies of oral microorganisms. However, the limitations of the probes must be kept in mind, and newly developed probes must be controlled with respect to the critical issues of sensitivity and specificity.

Cloning, Molecular↗
PubMed1990

Similarities in the microfloras of root canals and deep periodontal pockets.

Although not universally accepted, retrospective histological, roentgenological and microbiological studies have indicated that cross-infection can occur between infected pulps and deep periodontal pockets. This review provides examples of similarities in the microfloras of these adjacent oral sites, supporting the idea that infection spreads from one site to the other. The organisms most often involved are probably bacteroides, fusobacteria, eubacteria, spirochetes, wolinellas, selenomonas, campylobacter, and peptostreptococci. Important qualities of cross-infecting organisms may be the ability to survive in highly reduced environments and motility. Precautions should be taken to prevent in vivo seeding of such micro-organisms, particularly in compromised teeth and hosts.

Bacterial Infections↗
PubMed1990

Multivariate analyses of cellular carbohydrates and fatty acids of Candida albicans, Torulopsis glabrata, and Saccharomyces cerevisiae.

Quantitative data of major cellular carbohydrates distinguished Candida albicans or Torulopsis glabrata from Saccharomyces cerevisiae but not C. albicans from T. glabrata. Multivariate analyses of both carbohydrate and fatty acid variables (I. Brondz, I. Olsen, and M. Sjöström, J. Clin. Microbiol. 27:2815-2819, 1989), however, differentiated all three species.

Candida↗
PubMed1990

Clinical-mycologic diagnosis of oral yeast infections.

Conventional oral specimens for recovery of yeasts are swabs and smears. Oral rinses and imprint/impression cultures can also be used. Yeasts grow well at room temperature and may multiply in specimens under transport. Direct smears examined for blastospores, hyphae, and inflammatory cells ensure rapid presumptive diagnosis. Fungal identification requires culture, preferably on different media and at different temperatures to ensure recognition of all species present. YM agar supplemented with 0.01% aniline enables detection of Candida albicans and C. parapsilosis on primary plates through fluorescence. Microstix-Candida or Oricult-N slides can be read after culture at room temperature. Histologic sections for demonstration of yeasts require periodic acid-Schiff, Gridley, or Gomori's methenamine silver staining. Fungiqual staining enables non-specific diagnosis, also of rare oral mycoses, within 30 min, through fluorescence. Calcofluor white is even faster (less than 30 sec). Specific antibodies labeled with fluorescent stain enable more precise mycologic diagnosis. Mycologic findings should be interpreted together with clinical findings.

Candidiasis, Oral↗
PubMed1990

Chemotaxonomy of yeasts.

The present review deals with chemotaxonomic methods for yeasts. DNA base composition, which is expressed as molar percentages of guanine plus cytosine (G + C), is fitted for description of a new species and serves exclusionary functions. G + C content range among species within a genus is often 10% or less. Larger ranges may indicate an amalgam of genera. Typing and mapping of DNA may also be used for taxonomy. Strains showing 65% or greater relatedness after DNA-DNA hybridization may be considered members of the same species. With rRNA-DNA homology assessment, intrageneric relationships established are not usually meaningful, but intergeneric distances can be resolved. rRNA can be used for examining phylogenetic diversity of yeasts and alloenzyme variation to calculate genetic distances among large yeast populations. Furthermore, heterogeneity in coenzyme Q pattern, cytochrome spectra, composition of cell wall glucan, mannan, and chitin, and cellular fatty acids may serve chemotaxonomic purposes.

Base Composition↗
PubMed1990

Oral adhesion of yeasts.

Oral adhesion of yeasts probably occurs by interaction between yeast cell adhesins and oral epithelial cell receptors. In Candida albicans mannoprotein, glucan, chitin, cell wall proteins, and lipids are possible adhesins. Mannoprotein appears as a fibrillar or floccular outermost layer in stationary-phase cells grown in sugar-rich medium. Preincubation of buccal epithelial cells (BECs) with concanavalin A inhibits adhesion, as does suppression of mannoprotein production by tunicamycin. Germ tubes adhere more easily to BECs and plastic than do blastospores. Methyl-alpha-D-mannoside may be analogous to the yeast adhesin or epithelial cell receptor because it inhibits adhesion of C. albicans to BECs. L-Fucose, N-acetyl-D-glucosamine, or D-mannose, having the same effect, may also function as epithelial cell receptors. Other factors affecting yeast adhesion may be fibronectin, hydrophobicity, s-IgA, and indigenous bacteria. Growth of yeasts to stationary phase in sugar-rich media promotes adhesion to acrylic, as do divalent cations and serum. Saliva, chlorhexidine, and Streptococcus salivarius inhibit adhesion of yeasts.

Candida albicans↗
PubMed1990

Associations between six DNA probe-detected periodontal bacteria and alveolar bone loss and other clinical signs of periodontitis.

The purpose of the present study was to assess the associations between the presence and amounts of Actinobacillus actinomycetemcomitans, Bacteroides gingivalis, B. intermedius, Eikenella corrodens, Wolinella recta, and Fusobacterium nucleatum in the periodontal pocket and the degree of alveolar bone loss and other clinical signs of periodonitis, such as probing pocket depth, attachment level, and presence of bleeding on probing at the same site. The study material comprised 16 subjects with or without approximal sites showing longitudinal alveolar bone loss who were selected from a group of 142 subjects monitored radiographically over the past 4 years. In this group 105 sites were examined, of which 58 showed recent alveolar bone loss greater than or equal to 1 mm. Subgingival plaque was collected with absorbent paper points and hybridized with 32P-labeled DNA probes specific for the above-mentioned bacteria. The amount of each bacterial species was correlated with the degree of bone loss over time and the three clinical measurements by means of Spearman rank correlation. A. actinomycetemcomitans showed poor correlations with all three clinical signs of periodontal inflammation, whereas B. gingivalis and W. recta demonstrated significant positive correlations with the three clinical measurements and with attachment level and pocket depth, respectively. In addition, the amount of A. actinomycetemcomitans, B. gingivalis and W. recta showed significant positive correlation with the extent of alveolar bone loss at the site. In contrast, the amounts of B. intermedius, E. corrodens, and F. nucleatum showed negative correlations with all four measurements.(ABSTRACT TRUNCATED AT 250 WORDS)

Actinobacillus↗
PubMed1990

Invasive growth of Actinobacillus actinomycetemcomitans on solid medium (TSBV).

When grown on agar, most Actinobacillus actinomycetemcomitans form circular and convex colonies with an internal star-shaped morphology. Such colonies adhere firmly to the agar, and when removed, a star-shaped imprint similar to that of the intact colony remains. This study was undertaken to determine the nature of this in vitro growth. Stereo-microscopy and scanning and transmission electron microscopy showed that the star-shaped imprint of A. actinomycetemcomitans colonies reflected pseudopod-like extensions of the bacterial colony which penetrated deep into the TSBV agar. The center of the colonies consisted primarily of ghost-like cells, while the dense border of each colony, including the pseudopods, expressed characteristics of vital cells. The latter were embedded in vast amounts of extracellular vesicles, and the outer aspect of the pseudopods was lined with a border of such vesicles.

Actinobacillus↗
PubMed1989

Adhesion of lymphoid cells to fibroblasts in tissue culture.

In this study we have examined the cellular and molecular specificity of lymphocyte interaction with fibroblasts. Using mitogen-activated T-cells, we found that attachment to fibroblasts was highly sensitive to protease treatment, and to an antibody raised against the purified lymphocyte plasma membrane, but it was not mediated by the MEL-14 surface antigen or phosphomannosyl receptors. Lymphocyte interaction with fibroblasts was also unaffected by monoclonal antibodies against the LFA-1, Mac-1, and Class II MHC antigen complexes. In contrast, adhesion of both T- and B-lymphocytes was strongly inhibited by fucoidan, a polymer of sulphated fucose, whereas fucose, mannan, and mannose 6-phosphate had no effect. Both B- and T-lymphoid cell lines were able to recognise and adhere to fibroblasts, although the marked differences between the attachment of the different types of cell did not appear to be related to their immunological function. The attachment of most of the cell lines was prevented by the presence of fucoidan, whereas the inhibition of binding of each of the lymphoid lines in the presence of the anti-T-lymphocyte plasma membrane antibody varied widely. These findings suggest that lymphocyte attachment to fibroblasts involves multiple cell surface receptors, and that these are expressed at different levels on specific T- and B-cells.

Animals↗
PubMed1989

Chemical differences in lipopolysaccharides from Actinobacillus (Haemophilus) actinomycetemcomitans and Haemophilus aphrophilus: clues to differences in periodontopathogenic potential and taxonomic distinction.

While Actinobacillus actinomycetemcomitans has been associated with rapidly progressive periodontal destruction in man, the closely related Haemophilus aphrophilus has not been related to periodontal disease. This may be due to differences in composition and structure of the lipopolysaccharides (LPS) of these dental-plaque bacteria, since LPS probably exerts a series of detrimental effects on the periodontium. LPS was prepared by the phenol-water procedure from the type strains of A. actinomycetemcomitans and H. aphrophilus, purified by hexane extraction and ultracentrifugation, and analyzed with gas chromatography and gas chromatography-mass spectrometry. While the lipid content of LPS from A. actinomycetemcomitans constituted 35.4%, it was only 18.4% in H. aphrophilus: 3-hydroxytetradecanoic and tetradecanoic acids were 21.1 and 14.3% in A. actinomycetemcomitans and 10.9 and 7.5% in H. aphrophilus. There were qualitative and quantitative differences in the polysaccharide portions of their LPS. A actinomycetemcomitans contained both D-glycero-D-mannoheptose and L-glycero-D-mannoheptose (7.8 and 11.3%); H. aphrophilus contained only L-glycero-D-mannoheptose (17.4%). The rhamnose, fucose, galactose, glucose, and glucosamine/galactosamine contents in A. actinomycetemcomitans were 2.6, 5.2, 10.1, 22.4, and 5.2%, respectively; in H. aphrophilus, they were 2.1, 2.6, 19.4, 36.4, and 3.7%. Chemical differences in LPS from A. actinomycetemcomitans and H. aphrophilus may contribute to the divergence in periodontopathogenic potential of these organisms and help taxonomic differentiation.

Actinobacillus↗
PubMed1989

Gas chromatographic assessment of alcoholyzed fatty acids from yeasts: a new chemotaxonomic method.

An alternative chemotaxonomic method to methanolysis was developed for gas chromatographic assessment of fatty acids in whole yeast cells. Clinical and reference strains of the medically important yeasts Candida albicans, Torulopsis glabrata, and Saccharomyces cerevisiae were cultured for 48 h at 26 degrees C. Cellular lysis and transesterification were then performed with ethanol, propanol, butanol, or methanol. The relative recovery rates for cellular fatty acids, including the volatile acids C10:0 and C12:0, were similar after alcoholysis with ethanol, propanol, or butanol, while methanolysis gave lower recoveries of volatile fatty acids. Thus, after ethanolysis, the recovery of C10:0 acid (0.1, 1, and 10%) from a defined matrix (lyophilized Actinobacillus actinomycetemcomitans cells) varied from 97 to 102%, while the recovery of C10:0 after methanolysis varied from 49 to 75%. This indicated that with the frequently used methanolysis technique, there is a considerable loss of volatile fatty acids. These acids may be used as marker molecules for taxonomic differentiation between yeasts.

1-Propanol↗
PubMed1989

[Few aspects with regard to diagnosis and treatment of oral candidiasis].

The present article discusses the rationale for daily use of the combination of amphotericin B (4 lozenges) intraorally and chlorhexidine denture disinfection (15 min) extraorally vs separate use of polyene antimycotics or chlorhexidine in the treatment of infectious denture stomatitis, frequently considered as the most common form of oral candidiasis. The amphotericin B/chlorhexidine combination has been standard treatment of infectious denture stomatitis in Scandinavia for more than 15 years. It was found to be the best among several regimens tested in 100 patients after a series of subjective and objective parameters had been used to record treatment efficacy in controlled clinical and microbiological studies. The fact that there was a significant (5% level) higher reduction of yeasts cultured from the palatal mucosa with this drug regimen than with the other modalities tested, including chlorhexidine lozenges/chlorhexidine denture disinfection, suggested that no drug interaction of clinical importance took place in vivo with this combination. Therefore, care should be taken when extrapolating findings on drug interaction in vitro (12) to the in vivo situation, and guidelines for treatment of oral candidiasis should preferably be based on controlled clinical and microbiological trials with patients. In order to prevent relapse of oral candidiasis after treatment, local and general predisposing factors should be eliminated, in particular reestablishment of plaque on the fitting side of the denture should be prevented.

Candidiasis, Oral↗
PubMed1989

Fibroblast matrix and surface components that mediate cell-to-cell interaction with lymphocytes.

The interaction between lymphocytes and fibroblasts in vitro has been examined using a quantitative ELISA assay to measure the binding of T and B cells to monolayer cultures of human dermal fibroblasts. This was carried out on microtiter culture plates, using an anti-Thy-1 monoclonal antibody, to determine the attachment of murine T lymphocytes and an affinity-purified polyclonal anti-IgM antibody to measure B cell binding. Both types of lymphocyte were found to adhere strongly to intact human fibroblasts, and also had high levels of attachment to purified fibroblast plasma membranes and extracts of the fibroblast extracellular matrix. Attachment, particularly of B lymphocytes, also took place onto plastic surfaces coated with fibronectin, but not to collagens or to intact fibroblasts that had been fixed with a low concentration of paraformaldehyde. Lymphocyte binding to fibroblasts was partially prevented by a monoclonal antibody against fibroblast MHC class II antigens, but not against the class I membrane complex, or by polyclonal antiserum to the cell surface mannose 6-phosphate receptor. In addition, although both lymphocyte types were able to adhere to fibro-nectin, the presence of antibody against fibronectin or the synthetic peptide Arg-Gly-Asp-Ser, had no effect on their attachment to fibroblasts. Thus, lymphocyte adhesion may occur by fibronectin, but other types of interactions with fibroblasts also appear to take place.

Animals↗
PubMed1988

Cell contact induces the synthesis of a lysosomal enzyme precursor in lymphocytes and its direct transfer to fibroblasts.

The activity of a lysosomal enzyme, alpha-D-mannosidase (EC 3.2.1.24), increased markedly in normal lymphocytes when they were cultured together with fibroblasts from a patient with an inherited deficiency of this enzyme. Cell-to-cell contact was obligatory for this increase in activity, which also required new protein synthesis. The enzyme induced in the co-cultured lymphocytes was a high molecular weight form of alpha-D-mannosidase that was not detected in lymphocytes cultured alone, which had only the low molecular weight mature enzyme. It was this precursor form alone that was directly transferred to the mannosidosis fibroblasts, where it was present initially in organelles of low density. When the culture period was extended the lymphocyte precursor enzyme was transported to the heavy lysosomes in the recipient cells, and correctly processed to the functionally effective mature enzyme.

Animals↗