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Biomedical subjects

I Olsen

Publications and source records attributed to I Olsen.

At least 199 records · Page 11Linked to original sources
PubMed1986

Microbial chemotaxonomy. Chromatography, electrophoresis and relevant profiling techniques.

This review deals with the chemistry of marker substances used in microbial classification and identification, their isolation and purification and their biomedical application. A critical evaluation of current methods is also included. The information presented is partly based on personal experience, partly derived from more than 300 publications in this rapidly expanding field of science. Much has been done to improve the recognition of microorganisms by GC, but there are also a series of other techniques available that can assist in bacterial classification and identification. Some of these techniques have been made available to the clinical microbiologist through commercial systems, e.g., assessment of bacterial fatty acids. A fingerprint library has been developed by Hewlett-Packard for the analysis of fatty acids from approximately 6000 different bacteria. Other chemotaxonomic methods require great personal expertise and advanced equipment. Efforts should therefore be made to adapt and simplify such methods for application in the routine clinical laboratory. Chemical markers will probably have a great impact on future microbial taxonomy, particularly in cases where conventional methods fail to give satisfactory classifications. In order to make taxonomy more objective, there seems to be a need for screening of chemical markers in bacterial species and for compiling chemotaxonomic fingerprints in clinical manuals.

Bacteria↗
PubMed1986

Effects of cadmium acetate and sodium selenite on mucociliary functions and adenosine triphosphate content in mouse trachea organ cultures.

The effects of cadmium acetate and sodium selenite in mouse trachea organ culture have been studied separately and in combination. Ciliary activity, morphology, rate of total protein and glycoconjugate (i.e. glycoprotein and proteoglycan) synthesis/secretion and ATP content were investigated. Exposure to 10 microM cadmium acetate or 2000 microM sodium selenite resulted in a complete cessation of ciliary activity within 5 h. With cadmium acetate also a swelling of epithelial cells was observed. Sodium selenite (250-2000 microM) delayed by 2-3 h the inhibitory effect of cadmium acetate (5-20 microM) on ciliary activity. The rate of protein synthesis, as determined by incorporation of [3H]proline, was reduced by 13% and 44% at exposure for 4 h at 37 degrees C to 250 microM and 500 microM sodium selenite respectively, the effect being partly abolished by cadmium acetate. With 5 microM and 10 microM cadmium acetate the rate of glycoconjugate synthesis, as measured by incorporation of [3H]glucosamine, increased by 50% and 69%, respectively, after incubation for 4 h. This increase was partly reduced by sodium selenite. Neither cadmium acetate nor sodium selenite had any effect on the rate of total protein or glycoconjugate secretion. The ATP content in trachea rings was reduced by 48% and 54% after incubation for 4 h with 250 microM and 500 microM sodium selenite, respectively. No significant effect of cadmium acetate was found on ATP content. An antagonistic effect of sodium selenite and cadmium acetate in mouse trachea organ culture is suggested from the present experiments.

Acetates↗
PubMed1986

Role of cell adhesion in contact-dependent transfer of a lysosomal enzyme from lymphocytes to fibroblasts.

Normal lymphocytes were found to adhere strongly to monolayer cultures of fibroblasts deficient in the lysosomal enzyme, beta-glucuronidase. During this co-culture, the fibroblasts acquired from the lymphocytes substantial amounts of this enzyme, which often accumulated at sites of contact between the two types of cell. Enzyme transfer was prevented by addition to the co-cultures either of purified lymphocyte plasma membranes or of antibody raised against such plasma membranes, but it was not inhibited by the addition of antibody raised against lymphocyte-derived beta-glucuronidase. An active role for the lymphocyte in this contact-dependent process was suggested by interference contrast, immunofluorescence and scanning electron-microscopic studies. These revealed extensive arrays of projections of the lymphocyte that ramified over the fibroblast cell surface. By transmission electron microscopy, conspicuous clusters of micropinocytotic vesicles were evident in the cytoplasm of the 'recipient' fibroblasts, subjacent to the surface in regions closely apposed to adherent lymphocytes. Such high frequencies of these vesicles were restricted to sites of lymphocyte-fibroblast contact, suggesting that they may play an important part in the transfer of enzyme between these two types of cell.

Animals↗
PubMed1986

Effects of mitogenic stimulation on lymphocyte alpha-D-mannosidases.

Three types of alpha-D-mannosidase are present in human and murine lymphocytes. Their levels increased substantially when the cells were activated by T-cell mitogens, concanavalin A (Con A) and phytohaemagglutinin (PHA), and in the murine cells also by lipopolysaccharide (LPS), a B-cell mitogen. The intracellular localization of the alpha-D-mannosidases in the non-stimulated and activated murine cells was investigated by fractionation of lymphocyte lysates on colloidal silica (Percoll) and discontinuous sucrose gradients. In both types of cell, an enzyme having optimal activity at neutral pH was obtained in the cytosolic fraction and another alpha-D-mannosidase most active at an intermediate pH was obtained partly in membrane-bound form. In contrast, an acidic alpha-D-mannosidase, which was particularly elevated in the activated murine spleen cells, had a distribution in these lymphoblasts which was markedly different from that in non-stimulated lymphocytes. In the latter, the major proportion of the activity was obtained in a cytosolic fraction and the remainder in a particulate fraction of light density, whereas the enzyme in activated lymphocytes was distributed between vesicles of light and heavy density comparable with lysosomal organelles. Moreover, the acidic alpha-D-mannosidase still remained membrane bound even when cell lysates were prepared under hypotonic conditions which disrupt lysosome integrity. These results suggest that lymphocyte activation involves either stabilization of fragile lysosomes present in resting cells or de novo synthesis of lysosome-like structures. The acidic alpha-D-mannosidase present within isolated, intact lysosomes was found to be in a form, A, whereas a different form, B, was most prominent in whole-cell extracts of both types of lymphocyte.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Compartmentation↗
PubMed1985

Differentiation between major species of the Actinobacillus--Haemophilus--Pasteurella group by gas chromatography of trifluoroacetic acid anhydride derivatives from whole-cell methanolysates.

A method based on whole-cell methanolysis and trifluoroacetic acid anhydride derivatization was developed for routine laboratory differentiation between isolates from the Actinobacillus--Haemophilus--Pasteurella group. All species, except Haemophilus aphrophilus, contained D-glycero-D-mannoheptose, although in varying concentrations. The distribution of this sugar could be used to distinguish H. aphrophilus from Actinobacillus actinomycetemcomitans, H. paraphrophilus, H. influenzae type b, Pasteurella haemolytica, P. multocida and P. ureae, and also H. influenzae type b from Pasteurellae. The pattern of major sugars in P. ureae and P. haemolytica resembled that of A. actinomycetemcomitans. Major fatty acids of the whole-cell methanolysates provided no basis of interspecies differentiation.

Acetic Anhydrides↗
PubMed1985

Direct enzyme transfer from lymphocytes corrects a lysosomal storage disease.

Fibroblasts from patients with mannosidosis, the lysosomal storage disease resulting from an inherited deficiency of lysosomal alpha-D-mannosidase (EC 3.2.1.24), accumulate specific mannose-containing oligosaccharides which are characteristic of the disease (1,2). The present study shows that these substances were extensively degraded following transfer of the missing enzyme from normal lymphocytes to mannosidosis fibroblasts on direct contact in tissue culture. Moreover, prolonged correction of the metabolic abnormality of the recipient cells was sustained if contact with fresh donor lymphocytes was periodically renewed. These findings may be highly relevant to lymphocyte function in enzyme replacement therapy by transplantation procedures currently being attempted.

Animals↗
PubMed1985

Scanning electron microscopic observations on the inner surface of jaw cysts.

The cavity surface of 9 jaw cysts was studied in the scanning electron microscope. The material comprised 5 radicular, 2 residual, 1 dentigerous and 1 globulomaxillary cyst. The surface morphology varied from smooth to ruffled within the same cyst, and between cysts. Interepithelial spaces, some of which contained migrating leukocytes, were frequently observed. Bacteria occurred in 1 cyst (dentigerous) only, and included rods, filaments and spirochetes. Crystals of various morphology were seen in 6 of the cysts.

Adolescent↗
PubMed1985

Differentiation among closely related organisms of the Actinobacillus-Haemophilus-Pasteurella group by means of lysozyme and EDTA.

Bacteriolysis in Tris-maleate buffer (0.005 M, pH 7.2) supplemented with EDTA (0.01 M) and hen egg white lysozyme (HEWL, 1.0 microgram/ml) was set up to assist differentiation between the taxonomically closely related Actinobacillus actinomycetemcomitans and Haemophilus aphrophilus. A. actinomycetemcomitans was more sensitive to lysis in this system than H. aphrophilus. The standard method for bacteriolysis separated the 10 tested strains of A. actinomycetemcomitans into two groups (I and II) based on their lysis patterns, whereas the 7 strains of H. aphrophilus examined were homogeneous. In group I of A. actinomycetemcomitans, EDTA displayed a considerable lytic effect, which was not increased by supplementation with HEWL. In group II, the lytic effect of EDTA was much less, but HEWL had a considerable supplementary lytic effect. When the turbidity of A. actinomycetemcomitans (ATCC 29522) or H. aphrophilus (ATCC 33389) suspended in Tris buffer was monitored at close pH intervals (0.2) from pH 5.2 to 9.2, maximal lysis of ATCC 29522 occurred with EDTA at pH 8.0 and with EDTA-HEWL at pH 7.6, while ATCC 33389 lysed with EDTA at pH 9.0 and with EDTA-HEWL at pH 9.2. When other members of the family Pasteurellaceae (Haemophilus influenzae type b, Haemophilus paraphrophilus, Pasteurella multocida, Pasteurella haemolytica, and Pasteurella ureae) were included for comparison, the group I strains of A. actinomycetemcomitans were the most rapidly lysed by EDTA. H. paraphrophilus was the least sensitive of the gram-negative strains tested, but not as resistant as Micrococcus luteus (control). M. luteus was the organism most sensitive to lysozyme, followed by P. ureae and the group II strains of A. actinomycetemcomitans, while the group I strains of A. actinomycetemcomitans, H. paraphrophilus, and P. haemolytica were the least sensitive organisms.

Actinobacillus↗
PubMed1985

Five groups of antigenic determinants on DNA identified by monoclonal antibodies from (NZB X NZW)F1 and MRL/Mp-lpr/lpr mice.

A library of monoclonal antibodies (MCA) reactive with DNA was derived from mice with lupus-like disease. The combining reactions of the antibodies was determined by ELISA, precipitation assay and indirect immunofluorescence assay on cells. On the basis of their reactions in these assays, the MCA have been classified into five taxonomic groups. MCA in Group I react with conformational determinants on double-stranded DNA (dsDNA); those in Group II with conformational backbone-dependent sugar-phosphate determinants on dsDNA and single-stranded DNA (ssDNA); those in Group III with determinants predominantly expressed on ssDNA; those in Group IV with base-dependent determinants on ssDNA, and those in Group V with determinants on both DNA and RNA. It is concluded that antibodies which react with DNA are collectively of limited heterogeneity with regard to their specificity. The study illustrates how, upon traditional interpretation, different assay systems may give discordant results in the assignment of specificity to antibodies reactive with DNA.

Animals↗
PubMed1984

Differentiation between Actinobacillus actinomycetemcomitans and Haemophilus aphrophilus based on carbohydrates in lipopolysaccharide.

In the present study, the closely related facultative, Gram-negative rods, Actinobacillus actinomycetemcomitans and Haemophilus aphrophilus, were distinguished taxonomically by means of their carbohydrate composition in phenol-extracted lipopolysaccharide. Both A. actinomycetemcomitans and H. aphrophilus lipopolysaccharide contained rhamnose, fucose, galactose, glucose, L-glycero-D-mannoheptose, galactosamine, and glucosamine. The content of galactose was approximately twice as high in lipopolysaccharide from H. aphrophilus as in lipopolysaccharide from A. actinomycetemcomitans. D-Glycero-D-mannoheptose was detected exclusively in lipopolysaccharide from A. actinomycetemcomitans where it constituted 11.8-16.7% of the sugar content. This aldoheptose may therefore serve as a marker for chemotaxonomic differentiation between A. actinomycetemcomitans and H. aphrophilus. The present study also describes fragmentation of methylheptoside derivatives of trifluoroacetic acid (D-glycero- and L-glycero-D-mannoheptose) from A. actinomycetemcomitans as suggested by mass spectrometry.

Actinobacillus↗
PubMed1984

Determination of acids in whole lipopolysaccharide and in free lipid A from Actinobacillus actinomycetemcomitans and Haemophilus aphrophilus.

Acids from whole lipopolysaccharide and free lipid A of the closely related bacteria Actinobacillus actinomycetemcomitans and Haemophilus aphrophilus were determined by gas chromatography and gas chromatography-mass spectrometry. In whole lipopolysaccharide, 3-hydroxymyristic acid was most abundant, followed by myristic and 3-deoxy-D-manno-2-octulosonic acid. In the lipid A moiety, myristic acid dominated, followed by 3-hydroxymyristic acid. The acid composition of whole lipopolysaccharide and free lipid A from A. actinomycetemcomitans and H. aphrophilus was not so specific as to allow taxonomic differentiation between these bacteria. If fatty acids of lipopolysaccharide are essential for expression of endotoxicity, the present results suggested no marked difference in the endotoxic activities of A. actinomycetemcomitans and H. aphrophilus.

Actinobacillus↗
PubMed1984

A scanning electron microscopic study on the microflora of chronic pericoronitis of lower third molars.

In nine cases of chronic pericoronitis of lower third molars, the affected teeth were carefully removed with the follicles in situ and prepared for scanning electron microscopic (SEM) study. The study disclosed great heterogeneity in the distribution and density of microorganisms on hard as well as soft tissues surrounding the pericoronal pouch. Common features were presence of discrete microenvironments with clusters of bacteria, a decrease in the number of organisms toward the bottom of the pericoronal pouch, and the high proportion of spirochetes, which tended to increase in an apical direction. The study showed leukocytic activity in all areas, and phagocytosis apparently took place on the tissue surfaces within the pericoronal space.

Adult↗