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Biomedical subjects

W Fischlschweiger

Publications and source records attributed to W Fischlschweiger.

At least 19 recordsLinked to original sources
PubMed1991

Surface layers of Eubacterium yurii subsp. yurii and their possible role in test-tube brush formation and iron acquisition.

Eubacterium yurii subsp. yurii is an anaerobic, gram-positive rod. On isolation E. yurii forms cellular arrangements resembling test-tube brushes (TTB). Although TTB decreased in size and number on repeated laboratory subculture in enriched media, media poor in available iron enhanced formation of these. Plasmids were not demonstrated, even after chloramphenicol enhancement. To characterise the nature and possible physiological roles of the structures of the TTB, they were examined by transmission electronmicroscopy (TEM) with thin-section, negative-staining, shadow-casting, freeze-etching and freeze-fracturing techniques, and by scanning electronmicroscopy (SEM). Previous studies by phase-contrast microscopy revealed an amorphous core, the size of which varied in direct proportion to the number of associated bacterial cells. Thin sections of the TTB showed a gram-positive cell wall with additional surface layers. Negative staining, shadow casting and freeze etching revealed a surface layer comprising subunits in tetragonal array (P4 symmetry). Shadow casting showed also that the outermost layer of the cells was composed of fibrillar structures closely associated with but distinct from, the tetragonal layer. The fibrils extended from the cell surface in clumps or strands. The presence of these fibrils was confirmed by the freeze-fracture technique and SEM. Chemical analysis of the core material of the TTB showed it to be low in carbohydrate (0.06%) and protein (0.2%). Energy-dispersive X-ray spectrometry showed that the core was composed mostly of iron.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Adhesion↗
PubMed1990

Binding of colloidal gold-labeled salivary proline-rich proteins to Actinomyces viscosus type 1 fimbriae.

Salivary proline-rich proteins (PRPs), which were purified from parotid saliva, were adsorbed onto 15-nm-diameter gold particles to visualize specific binding of the salivary molecules to Actinomyces viscosus type 1 fimbriae. Negatively stained preparations incubated with PRP-gold conjugates but not bovine serum albumin-gold complexes bound specifically to bacteria possessing type 1 fimbriae, A. viscosus T14V-J1 and 5519. Binding of the PRP-gold probes to strains deficient in type 1 fimbriae, i.e., strains 5951 (type 2 fimbriae only) and 147 (no fimbriae), was negligible.

Actinomyces↗
PubMed1988

Oral granular cell tumors: a clinicopathologic and immunocytochemical study.

To investigate the histogenesis of the granular cell, a large series of granular cell tumors was studied for clinical and histopathologic features with emphasis on immunocytochemical markers. The nongingival granular cell tumors (NGGCT) were found to be more prevalent among females than males by a ratio of 2:1 and arose on the tongue (67%), the buccal mucosa (13%), the lips (8%), the soft palate (6%), and other sites (6%). With the use of the avidin-biotin-peroxidase method, polyclonal rabbit antisera were employed. The antisera were directed to the following antigens: S-100 protein, myoglobin, myosin, actin, desmin, alpha-1-antitrypsin, and muramidase. Results indicated that granular cell tumors are not homogenous for immunocytochemical markers. Nongingival granular cell tumors were universally positive for S-100 protein and failed to exhibit immunoreactivity for myogenous or histiocytic markers. Alternatively, the gingival granular cell tumor of infancy was negative for all markers, whereas rhabdomyoma was reactive with myogenous markers and a subpopulation of tumor cells displayed S-100 protein immunoreactivity. The granular cell ameloblastoma was reactive only with antiserum to alpha-1-antitrypsin. Ultrastructurally, granular cells from one of two NGGCT showed a direct evolution from skeletal muscle fibers. It is concluded that the oral NGGCT is a tumor positive for S-100 protein that may arise from muscle or nerve sheath.

Adolescent↗
PubMed1987

Intergeneric bacterial coaggregations involving mutans streptococci and oral actinomyces.

Mutans streptococci (MS) representing eight different serotypes were tested for their ability to coaggregate in vitro with oral actinomyces and other streptococcal species. Of the mutans streptococci tested, only strains of S. cricetus (formerly S. mutans serotype a) displayed pronounced coaggregations and only with certain strains of actinomyces. S. cricetus coaggregated, by lactose nonreversible mechanisms, with serotype 4 Actinomyces naeslundii WVU963 and WVU924 and with serotype 2 Actinomyces odontolyticus WVU758. The first pair was disaggregated by protein denaturants (e.g., sodium dodecyl sulfate and urea) and EDTA. This coaggregation was inhibited when the streptococcal, but not the actinomyces, partner was pretreated with either heat or protease, suggesting the presence of a protein mediator on only the streptococcal cell surface. The S. cricetus-A. odontolyticus coaggregation appeared to involve protein components on each cell, as shown by the lack of coaggregation after pretreatment of either cell type with heat or proteases. This coaggregation was also reversed by sodium dodecyl sulfate and urea, as well as by sodium deoxycholate, but not by EDTA. The data indicate that different mechanisms may be involved in each of these coaggregations.

Actinomyces↗
PubMed1984

Hydrolytic degradation of dental composites.

The leakage of filler elements from four composites after storage in water was investigated by use of atomic absorption spectrophotometry. The results confirmed previous findings that leaching of silicon from different composites is strongly dependent on filler composition. Consideration of the total filler surface of each composite material indicated that quartz as well as pyrolytic silica-containing composites leached less silicon than did composites containing fillers of strontium and/or barium glasses. A correlation between leakage and crack formation in the matrix appeared to exist for all composites except for the microfilled resin. These cracks were explained as a result of osmotic pressure built up at the matrix-filler interface due to hydrolytic degradation of the filler. Of the investigated materials, the microfilled resin was found to be the most stable material in a wet environment with respect to crack formation. This finding was explained by filler composition, filler form, and the specific structure of the microfilled resin.

Aluminum↗
PubMed1982

Morphological, chemical and antigenic characterization of M-1 N-acetylmuramidase-digested cell walls of the oral pathogenic bacterium Actinomyces viscosus T14V and T14AV.

The cell walls were enzymically solubilized with M-1 N-acetylmuramidase. The minimum amount of enzyme required for maximum response was 70 micrograms/mg of wall. The action of the enzyme seemed localized, producing holes in the wall structure. Chemistry and morphology suggested that all of the wall was solubilized. Antigenically, anti-T14AV formed precipitates with 11-14 antigens from the solubilized walls, of which 3 are unique to strain T14AV. Many of these antigens have not been observed previously due to the physical and/or chemical degradation associated with the extraction procedures. Antisera prepared against strain T14V whole cells formed precipitates with only a few antigens common to both strains. The results suggest that immunological processing and/or surface localization of these antigens are different.

Actinomyces↗
PubMed1982

The effect of force magnitude on extractable bone resorptive activity and cemental cratering in orthodontic tooth movement.

The delay period in the orthodontic tooth movement cycle was studied with respect to the stimulation of an extractable bone resorptive activity and the degree of tissue damage at sites of greatest pressure. Total area of cemental cratering was used as a measure of tissue damage. Both bone resorptive activity and tissue damage were found to be significantly increased with moderate and high forces, a fact which supports the suggestion that bone resorptive activity is related to tissue damage.

Alveolar Process↗
PubMed1981

Role of surface fimbriae (fibrils) in the adsorption of Actinomyces species to saliva-treated hydroxyapatite surfaces.

We studied the adsorption, morphological, and serological characteristics of selected Actinomyces and related species. Evaluation of uranyl acetate-stained cells by electron microscopy revealed wide variations among strains in the frequency of surface fimbriae. These variations did not always correlate with the percent adsorption to saliva-treated hydroxyapatite of the various Actinomyces strains. However, two strains of Rothia dentocariosa possessing no surface fimbriae and five strains of A. israelii possessing very few surface fimbriae exhibited feeble adsorption to saliva-treated hydroxyapatite. Although the calculated number of adsorption sites on saliva-treated hydroxypatite did not vary widely among the strains tested, significant differences were observed in the affinities calculated for some species or serotypes. The mean affinities for strains of A. viscosus serotype 2 and A. naeslundii serotype 3 were similar, and these strains adsorbed well to saliva-treated hydroxyapatite. The mean adsorption and affinity for the A. naeslundii strain serotype 1 and all strains of A. israelii tested were significantly less than those determined for the A. viscosus serotype 2 or A. naeslundii serotype 3 strains. Adsorption inhibition activity of antiserum to strain T14V, previously shown to be solely related to antibodies in immune serum directed against the VA1 fimbria (fibril) antigen, was removed by preadsorption of the antiserum with most A. viscosus and A. naelundii strains, but not with A. israelii strains. This suggests some cross-reactivity among strains of A. viscosus and A. naeslundii but not A. israelii. Adsorption to saliva-treated hydroxyapatite of all A. viscosus and A. naeslundii strains tested was strongly inhibited by fimbriae isolated from A. viscosus strain T14V. Collectively, these data suggest that the adsorption of certain A. viscosus and A. naeslundii strains is mediated by surface fimbriae, many of which appear serologically cross-reactive with strain T14V fimbriae.

Actinomyces↗
PubMed1980

Adherence of Pseudomonas aeruginosa to tracheal cells injured by influenza infection or by endotracheal intubation.

Adherence of Pseudomonas aeruginosa to normal, injured, and regenerating tracheal mucosa was examined by scanning electron microscopy. Uninfected and influenza-infected murine tracheas were exposed to six strains of P. aeruginosa isolated from human sources and one strain of platn origin. All of the strains tested adhered to desquamating cells of the infected tracheas, but not to normal mucosa, the basal cell layer, or the regenerating epithelium. Adherence increased when the incubation time of the bacteria with the trachea was prolonged. Strains isolated from human tracheas appeared to adhere better than strains derived from the urinary tract. After endotracheal intubation of ferrets, P. aeruginosa adhered only to the injured cells and to areas of exposed basement membrane. We call this phenomenon "opportunistic adherence" and propose that alteration of the cell surfaces or cell injury facilitates the adherence of this bacterium and that adherence to injured cells may be a key to the pathogenesis of opportunistic Pseudomonas infections.

Animals↗
PubMed1979

Characterization of the membrane fraction isolated by the fluorescein mercuric acetate technique of Barland and Schroeder.

Using scanning electron microscopy we have demonstrated that tha membrane fraction isolated by the fluorescein mercuric acetate technique of Barland and Schroeder (Barland, P. and Schroeder, E.A. (1975) J. Cell Biol. 45, 662-668) represents a topologically distinct membrane which circumscribes the cell nucleus. Our data suggest that not all the cells within a non-synchronized cell population release a membrane fraction after treatment according to the technique of Barland and Schroeder, but rather that the efficiency of membrane release achieved using this preparative technique is dependent on the morphology of individual cells. Our work has also demonstrated that the peptide composition of the membrane fraction isolated by the technique of Barland and Schroeder differs from the peptide composition of the plasma membrane-enriched fraction isolated by the technique of Brunette and Till (Brunette, D.M. and Till, J.E. (1971) J. Membrane Biol. 5, 215-224). This difference in peptide composition is particularly noticeable among the higher molecular weight proteins, glycoproteins and iodineateable membrane components. The data which we have accumulated suggest that the compositional differences noted between the two membrane isolates do not result from differential extraction of membrane components during the ZnCl2-fluorescein mercuric acetate treatments required in the isolation technique originally described by Barland and Schroeder. However, our data do clearly demonstrate that the membrane isolation technique of Barland and Schroeder cannot be used to study the general composition of the plasma membrane.

Cell Fractionation↗
PubMed1979

Murine influenzal tracheitis: a model for the study of influenza and tracheal epithelial repair.

The murine model of influenza virus infection is generally a lethal pneumonitis produced by a highly mouse-adapted virus. However, we infected mice with a less adapted virus and produced a nonlethal disease that involved the airways without producing gross pneumonitis. Changes that occurred in the tracheal epithelium were studied by scanning and transmission electron microscopy. Complete desquamation of the epithelium occurred within 3 days after infection, regeneration began within 5 days, and repair was complete within 2 wk after infection. This model is proposed as an alternative to the lethal pneumonitis for the study of murine influenza and also as a model for the study of repair of the respiratory ciliated epithelium.

Animals↗
PubMed1978

Modification of surface composition of Actinomyces viscosus T14V and T14AV.

The morphology and serology of Actinomyces viscosus T14V and T14AV were compared. When grown in supplemented tryptic soy broth, the virulent strain (T14V) possessed an extensive network of cell surface fibrils. In this medium, the avirulent strain (T14AV) possessed a microcapsule, absent on strain T14V, and a comparatively small number of surface fibrils. Mild acid extraction (Lancefield procedure) solubilized common antigenic components on both strains as well as components detectable only in the virulent strain T14V (virulence-associated antigens 1 and 2). When grown in Socransky chemically defined medium or Carlsson complex medium, the avirulent strain possessed increased amounts of surface fibrils and virulence-associated antigens. Whole cells and extracts of avirulent cells grown in Socransky medium absorbed antibodies to virulence-associated antigens with approximately the same efficiency as did whole cells and extracts of strain T14V, suggesting antigenic similarity between the two cell types. The results strongly support the hypothesis that observable differences between A. viscosus strains T14V and T14AV represent quantitative, rather than qualitative, differences in particular cell surface components. In addition, the magnitude of these differences can be modified by changing growth conditions.

Actinomyces↗
PubMed1978

Objective evaluation of surface microreplication by dental impression materials.

Twenty-two materials, including 19 dental impression elastomers, were compared in their ability to replicate microscopic detail. Some polysulfide, silicone, and polyether materials performed well. Curiously, microscopic replication ability generally correlated inversely with that expected from the nominal consistency. The test method developed appears to be a suitable microreplication evaluation standard.

Cellulose↗