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Biomedical subjects

R M Frank

Publications and source records attributed to R M Frank.

At least 73 records · Page 4Linked to original sources
PubMed1986

Immunological study of lactate dehydrogenase from Streptococcus mutans and evidence of common antigenic domains with lactate dehydrogenases from lactic bacteria.

Rabbit polyclonal antibodies directed against purified Streptococcus mutans L-(+)-lactate dehydrogenase reacted with the purified enzyme, giving a marked deviation of its kinetic parameters. The enzyme affinity for pyruvate or NADH decreased in the presence of antibody, the affinity for fructose 1,6-diphosphate (FDP) appeared to be slightly affected, and the cooperativity of the ligand binding was lowered. A partial protective effect was observed when the enzyme was preincubated with FDP prior to the antibody adjunction. An enzyme-linked immunosorbent assay allowed detection of a 30% decrease in enzyme-antibody fixation when FDP was added. The protective effect observed with FDP could be correlated with a conformational change induced by the activator. A decrease of antibody binding in the presence of FDP was also obtained with S. sanguis, Actinomyces viscosus, and Lactobacillus casei lactate dehydrogenases, which reflects a similar mechanism of activation among lactic bacteria. NADH did not offer any protection against antibody inhibition or fixation, and the coenzyme affinity decrease could be attributed to an indirect mechanism. On the contrary, pyruvate and the immunoglobulins apparently could compete for specific binding sites. A decrease of antibody binding was also obtained with three heterologous lactic bacterial lactate dehydrogenases, indicating a conservation of antigenic determinants implicated in the substrate binding.

Actinomyces↗
PubMed1986

Serum and salivary antibody responses in rats orally immunized with Streptococcus mutans carbohydrate protein conjugate associated with liposomes.

In this study we describe the preparation of a Streptococcus mutans vaccine consisting of a purified polysaccharide antigen, derived from S. mutans OMZ175 serotype f, covalently coupled through reductive amination to a previously isolated 74,000-molecular-weight (74K) cell wall protein which interacts with saliva proteins (74K-SR). We also investigated the local and systemic immune response to the poly-74K-SR conjugate after oral administration of the conjugate associated with liposomes. Intragastric administration of liposome-associated poly-74K-SR conjugate in rats produced a local immunoglobulin A (IgA) response directed against the polysaccharide and the cell surface protein, whereas liposome-associated polysaccharide was unable to induce any detectable local IgA response. The antigenicity of the polysaccharide in the conjugate was not affected by the coupling reaction, while that of the cell surface protein was reduced. We showed that the immunogenicity of S. mutans polysaccharide could be improved by chemical coupling with a carrier cell surface protein. If such a conjugate were orally administered with liposomes it could constitute a potential vaccine against dental caries.

Administration, Oral↗
PubMed1986

Ultrastructural development of dated plaque in case of denture stomatitis.

Using special acrylic discs glued into the palatal surface of a denture the development of denture plaque in a case of denture stomatitis as well as the relationships between the denture surface, pellicle, plaque and palatal epithelium were studied with transmission electron microscopy after 30 mn, 1 h, 4 h, 8 h, 24 h, 48 h, 9 days and 29 days. A thin pellicle which increased in thickness from 9 hours to 28 days was visible at the surface of the acrylic denture. It appeared that bacteria retained in the palatal epithelial intercellular spaces were the source of the plaque which developed at the surface of the acrylic denture. Initially loosely packed cocci-like and a few rod-shaped Gram positive bacteria appeared in 8 hours samples at the denture-epithelium interface. An important increase in denture plaque thickness was noted between 24 and 48 hours. In 9 and 28 days samples, coccoid and rod-shaped Gram positive and Gram negative bacteria were present and filamentous bacteria began to be apparent. In all the samples studied, Candida was rare.

Acrylic Resins↗
PubMed1985

Purification and characterization of a saliva-interacting cell-wall protein from Streptococcus mutans serotype f by using monoclonal-antibody immunoaffinity chromatography.

A rat monoclonal antibody, LO SM2, of the immunoglobulin M class, specific for a saliva receptor (SR) from Streptococcus mutans serotype f, was able to precipitate the SR from crude cell-wall-associated antigens (WEA) of this bacteria in presence of a detergent mixture. We have then used the technique of monoclonal-antibody immunoaffinity chromatography to purify the S. mutans SR. Pure SR was obtained from a crude WEA fraction with a single chromatographic step. The active SR could be eluted from the column in a highly purified form with 0.2 M-glycine/HC1, pH 2.8. The final yield was about 32% in terms of binding activity. Characterization of the SR by crossed immunoelectrophoresis, sodium dodecyl sulphate- or 4-30%-native-gradient-polyacrylamide-gel electrophoresis showed that the receptor is a single polypeptide chain of Mr approx. 74000. Native or denaturated forms of the SR adsorbed on to a solid support, such as nitrocellulose, are recognized by monoclonal antibody LO SM2, and both forms are still able to bind the ligand, saliva.

Antibodies, Monoclonal↗
PubMed1985

High-resolution transmission electron microscopy of adult human peritubular dentine.

Single crystals from adult human peritubular dentine were studied by high-resolution transmission electron microscopy. Periodic fringe patterns were obtained from which the exact shape of the inorganic crystals were deduced. The crystals were found to have a mean length of 36.00 +/- 1.87 nm, a mean width of 25.57 +/- 1.37 nm, and a mean thickness of 9.76 +/- 0.69 nm. They consisted of platelets with a mean width-to-thickness ratio of 2.61, each being a flattened hexagonal prism of hydroxyapatite. Such conclusions are based upon the electron diffraction patterns that we obtained, and our comparison of the values of the periodic, equidistant fringes seen along different planes of sectioning with the corresponding theoretical values for hydroxyapatite.

Adolescent↗
PubMed1985

Transmission electron microscopy of plaque accumulations in denture stomatitis.

Denture pellicle in denture stomatitis has been studied with transmission electron microscopy after embedding the denture base in a water-miscible resin in seven patients with heavy plaque deposits on their dentures and in five patients with no apparent plaque accumulation. In the first group, the denture surface was covered by a well differentiated granular pellicle. A cell-free zone was interposed between the pellicle and the plaque, which consisted predominantly of rounded, rod-shaped, and filamentous microorganisms with a loose distribution, separated by an electron-lucent amorphous and gel-like matrix. C. albicans were scattered among the bacteria and often presented with degenerated cytoplasm. In the second group, a structurally heterogeneous pellicle was seen adjacent to the denture surface. A thin plaque that consisted mainly of dense accumulations of C. albicans, a narrow dense matrix, and few bacteria was found. Calculus accumulations on the dentures consisted of amicrobial calcifications in the deeper layers, whereas the superficial parts showed bacterial calcifications.

Bacteria↗
PubMed1985

Lactate dehydrogenase from Streptococcus mutans: purification, characterization, and crossed antigenicity with lactate dehydrogenases from Lactobacillus casei, Actinomyces viscosus, and Streptococcus sanguis.

A cytoplasmic fructose-1,6-diphosphate-dependent lactate dehydrogenase (LDH; EC 1.1.1.27) from Streptococcus mutans OMZ175 was purified to homogeneity as judged by sodium dodecyl sulfate-gel electrophoresis. The purification consisted of ammonium sulfate precipitation of the cytoplasmic fraction, DEAE-Sephacel and Blue-Sepharose CL.6B chromatography, and Sephacryl S200 gel permeation. The catalytic activity of the purified enzyme required the presence of fructose-1,6-diphosphate with a broad optimum between pH 5 and 6.2. The concentration of fructose-1,6-diphosphate required for half-maximal velocity was around 0.02 mM and was affected by the pyruvate concentration. The enzyme seemed to have at least two binding sites for the activator which interact in a cooperative manner. Increasing concentrations of fructose-1,6-diphosphate up to 2 mM enhanced the relative affinity of the enzyme for pyruvate and modified the pyruvate saturation curve from sigmoidal to hyperbolic. The enzyme activity showed also a sigmoidal response to NADH, exhibiting two binding sites for the cofactor with a Hill coefficient of about 1.9. The molecular weight of the native enzyme was 150,000 as determined by gel permeation on Sephacryl S200. Monomers (38,000 daltons) and dimers (85,000 daltons) were observed by sodium dodecyl sulfate-gel electrophoresis; the latter form was dissociated after reduction with 2-mercaptoethanol, and the enzyme could be considered a tetramer. Antibodies obtained against the purified S. mutans OMZ175 LDH cross-reacted with the sodium dodecyl sulfate-dissociated forms of LDHs from different S. mutans serotypes, Streptococcus sanguis OMZ9, Lactobacillus casei ATCC 4646, and Actinomyces viscosus NY 1. A competitive enzyme-linked immunosorbent assay allowed us to detect a very close relationship between the native states of L-LDHs from S. mutans serotypes and S. sanguis. Cross-reactions were also observed with the LDHs from A. viscosus and L. casei, the latter being the least related. A very weak immunological relationship was obtained between the L-LDH from S. mutans OMZ175 and the D-LDH from Lactobacillus leichmannii, whereas no cross-reaction could be detected with mammal LDHs.

Actinomyces↗
PubMed1985

Antibody specificity and antigen characterization of rat monoclonal antibodies against Streptococcus mutans cell wall-associated protein antigens.

Monoclonal antibodies to Streptococcus mutans OMZ175 (serotype f) cell wall-associated antigens (wall-extracted antigens [WEA]) were derived from the fusion of Lou C plasmocytoma rat cells (IR 983 F) and spleen cells from Wistar R inbred rats immunized with WEA. Four cell lines producing monoclonal antibodies directed against a component of S. mutans WEA have been established. All four monoclonal antibodies reacted only with two antigens of WEA from S. mutans OMZ175 by Western blotting and immunoprecipitation techniques, enzyme-linked immunosorbent assay (ELISA), and competitive ELISA. Western blot analysis of WEA showed that the four monoclonal antibodies recognized two related cell wall-associated proteins with apparent molecular weights of 125,000 and 76,000. Immunoprecipitation of whole cells with the monoclonal antibodies confirmed the surface localization of the two antigens. The ELISA and competitive ELISA were used to analyze the distribution of the epitopes on seven S. mutans serotypes. All S. mutans serotypes were found to express the recognized epitopes; however, different reactivity patterns could be distinguished among the various strains tested, and the four monoclonal antibodies reacted only weakly with S. mutans serotypes d and g.

Animals↗
PubMed1985

A survey of the reasons for dental extractions in France.

3516 French dentists, selected at random, were asked to record every tooth they extracted during January, 1984. They were also asked to give the reason for extraction in each case. These were assigned to eight groups: caries, periodontal diseases, eruption problems, prosthetics, trauma, orthodontics, occlusal problems, and other reasons. Data were received from 910 dentists (25.3%) relating to a total of 14,621 extractions. Overall, caries was the most frequent cause for extraction (49%), followed by periodontal diseases (32.4%) and orthodontics (8.4%). In the age group under 50, dental caries was the main reason for extraction. However, in the age group over 50, periodontal diseases became the principal reason for extraction. Orthodontic extractions were most prominent in the 6-12 and 13-20 age groups, with respective frequencies of 72.6% and 24.8% of all extractions. Eruption problems contributed most frequently in the 13-20 and 21-30 age groups, their respective percentages being 8.7% and 12.3%. Extractions resulting from trauma were most frequently noted in the under-6 age group (frequency of 8.8%). As far as the type of tooth was concerned, first and second molars taken together made up 29.6% of extractions. These were followed by pre-molars, anterior teeth, and third molars at levels of 25.8%, 29.9%, and 14.7%, respectively. The teeth most frequently extracted because of caries were the molars (40.9%); because of periodontal disease, the anteriors (49.1%); and, for prosthetic reasons, again the anteriors (57.5%). Extractions from the various regions of France showed important variations. Percentage frequencies for caries and periodontal extractions were inversely linked.

Adolescent↗
PubMed1985

The extent of the human odontoblast process as determined by transmission electron microscopy: the hypothesis of a retractable suspensor system.

After fixation of fully formed human permanent teeth in liquid nitrogen the extent of the odontoblast process has been studied in transmission electron microscopy. The odontoblast process, limited by a trilaminar plasma membrane, was found just under the dentine-enamel junction. In cross section, the cytoplasm contained a granular mass with light and/or dense core granules. Bare unmyelinated nerve-like fibrils were seen in close connection with the odontoblast process. In the periodontoblastic space non calcified collagen fibrils were occasionally present. Cytoplasmic globules and granules limited by a trilaminar membrane, with occasional myelinic figures were also noted in the peripheral tubular lumens. The hypothesis of a retractable suspensor system is advanced to explain why in normal fixation conditions the odontoblast processes associated with nerve fibrils have not been observed in the outer layers of dentine.

Adolescent↗
PubMed1985

Immunoelectrophoretic study of cell surface antigens from different Streptococcus mutans serotypes and Streptococcus sanguis.

Antigens prepared from culture supernatants or whole cells of several cariogenic strains were examined by immunoelectrophoresis for their crossed antigenicity, with reference to Streptococcus mutans OMZ175, serotype f. Crossed immunoelectrophoresis revealed a crossreactivity between soluble extracellular and wall associated antigens of six strains of Streptococcus mutans and one strain of Streptococcus sanguis. Protease destroyed the immunoreactivity of crossreactive antigens. One of them was shown to be localized on the bacterial surface.

Antigens, Surface↗
PubMed1985

Ultrastructural relationship of denture surfaces, plaque and oral mucosa in denture stomatitis.

Denture plaque has been studied by transmission electron microscopy in glycolmethacrylate-embedded specimens from six patients presenting with typical denture stomatitis. Different types of thin and thick pellicles were found applied to the denture surface. These were in contact with a denture plaque made up predominantly of loosely packed Gram- positive and Gram- negative bacteria. Rounded, rod-shaped and filamentous micro-organisms were all evident. Group of Candida albicans with normal ultrastructure were noted in some limited zones. When surrounded by bacteria, especially by bacteria in corn-cob configurations the Candida showed cytological signs of degeneration. In one case out of six a bacterial penetration of the acrylic denture base was observed, through narrow and straight channels and subsurface cavities filled with micro-organisms. Bacterial penetration was also seen in the most superficial cell layers of the palatal mucous membrane.

Aged↗
PubMed1985

Local and systemic immune response to orally administered liposome-associated soluble S. mutans cell wall antigens.

The aim of the present study was to develop an immunization procedure which preferentially stimulated the IgA system of rats, with release of IgA in secretions. Rats immunized by intragastric route with liposome-associated soluble antigen extracted from Streptococcus mutans cell wall, showed a significantly higher IgA (and IgG) response than did rats injected with the soluble antigen alone. In saliva, maximal antibody titres were obtained 11 days after the beginning of intubations for IgA, and 16 days for IgG. After a booster immunization, the secondary response occurred very quickly in saliva and, like the primary response, it was almost exclusively of the IgA class. This demonstrates, on one hand the existence of immunological memory in the IgA system and, on the other, the efficiency of liposomes as insoluble adjuvants in eliciting an immunological response.

Administration, Oral↗
PubMed1984

Identification and preliminary characterization of saliva-interacting surface antigens of Streptococcus mutans by immunoblotting, ligand blotting, and immunoprecipitation.

The ability of surface protein antigens of Streptococcus mutans to interact with salivary components was examined by Western blot and immunoprecipitation methods. Immunoblotting of S. mutans OMZ175 wall-associated antigens revealed 10 major antigens, designated according to their estimated molecular weights. Four of them, with molecular weights of 135,000, 125,000, 120,000, and 115,000 in their denaturated form, bound salivary components. This property was further investigated by immunoprecipitation experiments: the reactivity with saliva was confirmed for antigens with molecular weights of 135,000, 125,000, and 120,000 in their native form, and their locations on the bacterial cell surface were established. These three antigens were characterized as glycoproteins; they directly bound concanavalin A, and pronase abolished their antigenicity, which was partly retained after treatment with NaIO4. Because of their distribution in several other stains of S. mutans, it will be of interest to study their possible implication in the mechanism of attachment of streptococcal strains to saliva-coated tooth surfaces.

Antigen-Antibody Complex↗
PubMed1984

Tooth ultrastructure of late triassic Haramiyidae.

Six molars of Haramiyidae from the French lower Rhaetic were examined by scanning and transmission electron microscopy, and by electron diffraction. Typical polished wear facets were located on the tops and on the occlusal bases of cuspids. Enamel was found to have had a structural pattern defined as "pre-prismatic", consisting of a repetitive pinnate orientation of the c-axes of apatite crystallites but without interprismatic material. Peritubular dentin was not found, but hydroxyapatite deposition in the dentinal tubular lumens was observed, whereas typical denticles with dentinal tubules and hydroxyapatite deposits were located in the pulp chambers. Taken together, these different features are strongly indicative of mastication, and hence enforce the suspected mammalian status of the Haramiyidae.

Animals↗
PubMed1984

[Longitudinal study of the evolution of the frequency of dental caries in a school milieu: a statistical model].

Following a 3-year epidemiological study of the appearance of dental caries in a population of children aged 6 to 9 years (and examined every 12 months), a model of the evolution of the frequency of caries based on a Poisson "with zeros" distribution is proposed. The multivariate distribution of the above phenomena appears as a mixture of multiple negative binomial distribution (MNB) of the following form: sigma mjMNB(a;k0jb,k1jb,k2jb) with sigma mj = 1. The experimental data from the sample of 501 children validate the model in its successive stages. Simulations using the bootstrap method show that the estimates of the model parameters remain stable in the neighbourhood of the distribution observed; at the same time they permit establishing the margins of confidence. Finally, it is shown why the total number of dental faces affected during the experimental period remained strongly asymmetrical.

Child↗