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Biomedical subjects

R M Frank

Publications and source records attributed to R M Frank.

At least 109 records · Page 6Linked to original sources
PubMed1980

Glucose and sucrose effects in the culture media on Streptococcus sanguis OMZ 9 glucosyltransferase inhibition by anti-glucosyltransferase antibodies.

An anti-glucosyltransferase serum was prepared against a purified enzyme of Streptococcus sanguis OMZ 9. Antibody fractions obtained after gel filtration on a Bio-Gel P200 column were used to study enzyme-antibody interaction in broth culture containing either sucrose or glucose, and to localize ultrastructurally the enzyme on thin sections of bacteria using labelled and unlabelled antibodies. The antibody fractions had no effect on bacterial growth in broth culture. A strong inhibition of insoluble and soluble polysaccharides synthesis was obtained in batch culture after a 24 hours incubation of bacteria with rides synthesis was obtained in batch culture after a 24 hours incubation of bacteria with antibodies. The GTF was localized at different cellular levels on bacteria grown in glucose but the ultrastructural method failed to localize GTF in sucrose grown cells.

Antibodies↗
PubMed1980

[Scanning electron microscopy of dental plaque and tartar on the surface of human cementum].

Supragingival plaque covering cementum, exposed through withdrawal of the epithelial attachment, presented the same bacterial polymorphism as nature dental plaque. Rounded, filamentous and rod-shaped organisms were observed. In some areas, the presence of extracellular material corresponded to plaque matrix. Corn cob configurations consisting of central filamentous bacteria associated with peripheral cocci were often seen in the supragingival plaque overlaying the cementum. The observation of cementum calculus allowed the differentiation of supragingival and subgingival calculus. The first consisted mostly of calcified dental plaque. The calcification started more often in the interbacterial matrix, but sometimes an initial calcification of the bacterial bodies was noted. Beside this calcified bacterial plaque, crystalline inorganic deposits devoid of micro-organisms were observed. The same differences were noted in subgingival calculus but the proportion was clearly reversed. Amicrobial crystalline deposits were more frequent and calcified bacteria were more uncommon.

Bacteria↗
PubMed1980

[Scanning electron microscopy of the surface of human cementum in various physiological and pathological conditions].

In scanning electron microscopy (SEM) of the dental root surfaces human cementum resorption by giant multinucleated cells appeared similar in temporary and permanent teeth. Thus the resorbed zones were formed by associated Howship lacunae. On the lacunae walls, the openings of numerous tubules of the cementocytic lacunae were seen. Such aspects were noted during the physiological resorption of temporary teeth. The cementum surface of permanent teeth without pathology, presented frequently such resorption aspects around their apical regions as well as on other regions, the resorbed areas being more often not widespread. Similar resorption zones were observed in contact with paradental granulomas and along granulation tissue in cases of chronic periodontitis. Orally exposed cementum, after gingival recession, was mainly characterized by the disappearance of the typical dappled aspect of the cellular cementum and by the presence on the smoothed surface of numerous striate. The cementum wall of the periodontal pockets showed always the dappled aspect with the occasional presence of incipient calculus formation as well as calcified fibrillar elements. These calcified fibrils were either short covering the whole surface or were longer being disposed parallel to the surface in interwoven networks or in tufts. Cementum curetage followed by root planning removed the calculus completely. Before root planning, the presence of numerous striae were noted. They disappeared following the action of a rubber cup and an abrasive polishing paste. Ultrasonic scaling gave a relatively clean root surface. However, the cementum surface, apparently devoid fo calculus under visual examination, showed in places the presence of thin calculus layers under the SEM.

Dental Cementum↗
PubMed1979

Tooth enamel: current state of the art.

Important progress has been made relative to the growth, structure and function of enamel. Better understanding of the epithelial mesenchymal interactions during odontogenesis has been gained through tissue culture, and the predominant role of the dental papilla has been established. Differences between rodent and human amelogenesis have been demonstrated. With radioautography and cytochemistry, a significant amount of new information has been obtained on the metabolism of the ameloblasts, concerning the synthesis of proteins, glycoproteins and proteoglycans, as well as calcium transport. Numerous biochemical investigations have been devoted to developing and mature enamel matrix. The organic components of human adult enamel are mainly constituted of lipids and proteins, but further investigations are still needed to elucidate their precise nature. The so-called key-hole configuration of adult enamel can be questioned when amelogenesis is considered since the tissue does not develop in a prismatic head-tail fashion. The most important results have probably been obtained in the field of individual enamel apatite crystals shape and ultrastructure as well as in the description of the precise patterns of their carious dissolution which bears great similarities to the dissolution of synthetic apatites in acids.

Amelogenesis↗
PubMed1979

3H-glucosamine electron microscope autoradiography after isolated labeling of the enamel organ or the dental papilla followed by reassociated toothgerm culture.

Electron microscope autoradiography was performed after isolated labeling with 3H-glucosamine of the enamel organ or the dental papilla of Swiss mice followed by reassociated toothgerm culture for 9.30 h and 19 h. After these two time intervals in case of an enamel organ labeling, numerous silver grains were observed in the intercellular spaces of the stellate reticulum indicating a concentrating and storing role of the latter. After dental papilla labeling, an almost complete absence of radioactivity was noted at 19 h. suggesting that 3H-glucosamine is not stored by the dental papilla. A clear labeling of the basement membrane area and of the adjacent aperiodic filamentous material found on the pulpal side was only observed after enamel organ labeling with 3H-glucosamine, suggesting an epithelial origin of the glycosaminoglycans found in these structures.

Animals↗
PubMed1979

[Influence of culture media on the growth of Streptococcus mutans ATCC 25175 in the presence of various carbohydrates and their derivatives].

The growth of Streptococcus mutans ATCC 25 175 has been studied in the presence of various sugars (sorbitol, mannitol, lycasin, sorbose and xylitol) and compared to sucrose, glucose and fructose, added to a complex and a synthetic culture medium. In these two media, the decrease in pH was related to the bacterial growth; this fact was confirmed by the dosages of the liberated lactic acid. In the complex medium, the different sugars influenced only slightly the bacterial growth, whereas in the synthetic medium the micro-organisms did not grow in the presence of sorbose, xylitol or lycasin 80/55. An adaptation period was necessary before the beginning of bacterial growth in the synthetic medium supplemented with sorbitol and mannitol.

Carbohydrates↗
PubMed1978

Immunogenic properties of the glucosyltransferase from Streptococcus sanguis OMZ 9: kinetic study of inhibition by antibodies.

An anti-glucosyltransferase serum was prepared against a pure enzyme preparation from Streptococcus sanguis OMZ 9, which synthesized both soluble and insoluble dextran. Sera, crude gamma globulins, and antibody fractions obtained after gel filtration on a Bio-Gel P200 column were used to study enzyme-antibody interactions. A strong inhibition of glucosyltransferase activity was obtained only with the purified antibody fraction. Kinetics studies showed that the anti-glucosyltransferase antibodies acted as noncompetitive inhibitors with respect to the substrate (sucrose). The addition of primer dextran in the reaction mixture during preincubation produced a diminution of the inhibition, and the antibodies acted as mixed type inhibitors with respect to dextran. The simultaneous addition of dextran and antibodies can protect the enxyme against antibody inhibition.

Antibodies, Bacterial↗
PubMed1978

[The brown line of Retzius in scanning electron microscopy].

A study in scanning electron microscopy of the striae of Retzius of human enamel, on longitudinal and transverse sections, has shown thin striae and relatively broad bands. The thin striae of Retzius consisted in narrow zones devoided of mineral material which extended obliquely through the prisms. These latter were interrupted at the level of the striae. A thin dense layer bordered sometimes unilaterally the striae of Retzius. The relatively large band-like structures involved several prism rows and can be considered as hypomineralized enamel.

Adolescent↗
PubMed1977

Stages in the dissolution of human enamel crystals in dental caries.

Various stages in monocrystal dissolution occurring during human enamel were studied by high resolution transmission electron microscopy. After the development of a central core lesion, two mechanisms by which the dissolution spread laterally to the (100) faces of the crystal could be demonstrated on the basis of the systematic orientation of the crystallographic axes. In the first case, the destruction was developing parallel to (120) planes and the borders were limited by (100) planes. In the second type, the development of the lateral side lesion was observed parallel to (100) planes. The carious destruction of the enamel monocrystal occurred as a result of the development of several lateral side dissolutions of the two types described, proceeding along the entire central core lesion.

Adolescent↗
PubMed1977

Ultrastructure of lymphatic capillaries in the human dental pulp.

Occlusal intradentinal cavities, prepared in normal human premolars and third molars to be extracted for orthodontic reasons, were filled for 7 to 11 days with gutta percha. A superficial pulpitis with localized small abscesses developed in the pulp chamber. Under local anesthesia, 0.2 to 0.3 cc of sterile colloidal carbon was injected in the pulp horn and the teeth were extracted 1 to 3 h later. Lymphatic capillaries could thus be identified in the pulpal tissues. They were characterized by a thin endothelium with occasional large intercellular clefts, absence or incompleteness of basement membrane, absence of pericytes, absence of luminal red blood cells, and presence of a filamentous material between the endothelium and the surrounding collagen fibrils. Moreover, some structural variations were observed.

Adolescent↗