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Biomedical subjects

R M Frank

Publications and source records attributed to R M Frank.

At least 127 records · Page 7Linked to original sources
PubMed1977

Oral conditions in a population of young adults in Strasbourg.

The oral conditions of 1,993 young adults, 16-30 years old, constituting a statistically representative random sample of the population of Strasbourg, were studied. Plaque, calculus, and gingival indices were determined as well as DMFT and DMFS caries indices. All these indices showed a highly statistically significant linear correlation with age. Sex had a significant influence on caries indices but not on plaque, calculus, or gingival indices. Socioprofessional conditions had a very significant influence on caries and gingival indices but not much on plaque index and not at all on calculus index.

Adolescent↗
PubMed1977

Inhibition of glucosyltransferase by human salivary immunoglobulin A.

Purified glucosyltransferase isolated from Streptococcus sanguis OMZ 9 and different immunoglobulin A from saliva, saliva pellet, and dental plaque were used to study enzyme-antibody interactions. A strong inhibition of glucosyltransferase activity was obtained with the different immunoglobulin A fractions.

Glucosyltransferases↗
PubMed1977

Ultrastructural study of apatite crystal dissolution in human dentine and bone.

The width and thickness of normal apatite monocrystals were determined in human dentine and alveolar bone on non-decalcified thin sections made perpendicular to the c axis. A mean width (L) of 364.50 A +/- 14.50 A and 562.10 A +/- 19 A was respectively found for dentine and bone monocrystals, whereas their mean thickness (E) was respectively 103.30 A +/- 2.70 A and 79.10 A +/- 3.10 A. The study of the ratio L.E.-1 for dentine and bone monocrystals showed a plate-like configuration which was more accentuated in bone crystals. Apatite crystal dissolution was studied during the carious process in dentine and bone resorption during advanced periodontal lesions. It could be shown that, in both conditions, one or several central core lesions developed along the c axis of the crystals. These central core lesions, extending laterally along (100) planes, progressively fused together, leading to the splitting up of the monocrystals into two thin plates by a complete destruction of the central part of the monocrystal.

Adolescent↗
PubMed1977

Collagen resorption by fibroblasts in human gingiva.

In the course of the extensive tissue remodeling occurring after flap surgery and during the subsequent gingival reattachment in man, numerous intracellular vacuoles were observed in fibroblasts of the lamina propria. These vacuoles contained one or several typical collagen fibrils and had either an electron-lucent matrix or contained an electron-dense material obscuring the fibrillar outlines and cross-striations.

Adult↗
PubMed1977

[Ultrastructure of the ligamental surface of the rat alveolar process].

The ultrastructural study of the alveolar bone surface of adult rat molars has shown the presence of resting, developing and resorbing areas. Intermediary, tight and gap junctions were observed between the cell processes of osteoblasts and osteocytes. In developing zones, the progressive differentiation of bone lacunae was followed. In resting zones, fibroblast-like cells with large intercellular spaces were observed. The ultrastructure of the osteocytes and the organic periosteocytic space was variable. The osteoclastic resorption showed an initial mineral attack followed by a collagen breakdown. Some observations suggested a relationship between the osteocytes and the origin of the osteoclast.

Alveolar Process↗
PubMed1977

[Ultrastructural study of the cellular cementum in rats].

The study of the cementum of adult rat molars has essentially shown resting and developing surfaces. The resting cementum surface is covered by fibroblasts oriented perpendicular to the surface and surrounded by collagen bundles entering perpendicularly in the cementum or oriented parallel to the surface. On the surfaces with apposition, cementoblats and cementoid cementoblasts, becoming finally cementocytes, were observed. A decrease in cytoplasmic organelles is noted in these latter cells when going from the surface to the cementum depth. An organic pericementocytic space is located between the comentocyte cytoplasmic membrane and the lacunar calcified wall. In the interlacunar tubules, tight and gap junctions were present between the cytoplasmic processes of adjacent cells. Groupings of several epithelial-like cells were embedded in large intracemental cavities. They probably correspond to epithelial rests of Malassez.

Animals↗
PubMed1976

The study of human dentine with secondary ion microscopy and electron diffraction.

The highly polished surface of serial transverse ground sections of human coronal dentine were coated under vacuum with an aluminium grid and studied with a SMI 300 ion microanalyser (Cameca, Paris) based on mass spectrography. Secondary ion microscopy demonstrated a qualitative distribution of calcium, phosphorus, magnesium, sodium and potassium. A higher content in Ca, P and Mg was noted in peritubular dentine. Selective area electron diffreaction patterns of this zone, using LiF as standard, showed the presence of whitlockite in peritubular dentine where about 1% in weight of magnesium seemed to be incorporated.

Adolescent↗
PubMed1976

[Study of dental fluorosis using an ionic microanalyzer].

Permanent teeth with endemic dental fluorosis, showing mild and moderate mottled enamel, according to the classfication of Dean, were examined with a SMI 300 Cameca ion micro-analyser. In the external third of enamel, abnormally large "sheaths" were disclosed as well as zones characterized by the destruction of prisms. In the dentine, the presence of peritubular dentine rich in Ca, P, FCa, PO, Mg, Na and K has been noted. Hypomineralized spots, poor in these various elements were observed in the intertubular dentine.

Dental Enamel↗
PubMed1976

[Segmentation analysis of the oro-dental health of a population of young adults].

The results of an epidemiological study of the oral conditions in a representative sample of 2000 adult inhabitants of Strasbourg, 16 to 30 years old, have been analyzed by the segmentation method. The gingival conditions were essentially dependent on dental plaque, followed by age, socio-professional status, as well as DMF/S and sex. Dental caries was mainly related to age and then to gingival conditions and sex. The amount of calculus and the socio-professional conditions intervened afterwards. In all conditions, the females had more carious lesions than the males.

Adolescent↗
PubMed1976

[Ultrastructure of the alveolodental ligament of the rat].

The ultrastructural study of periodontal ligaments of adult rat molars showed that the predominant cellular element consisted of fibroblasts and fibrocytes. These cells were responsible for the elaboration of the collagen precursors and for their destruction as was demonstrated by the presence of ellipsoidal intracytoplasmic vacuoles containing collagen. The abundance of microfilaments and microtubules as well as the presence of intermediary and tight junctions and nexus between the cell processes seemed to indicate that these cells are contractile and motile. Other cell types were intrequent. The ligament presented a high density of collagen fibrils grouped in bundles. Oxytalan fibrils were also observed. The blood capillaries showed mainly a continuous endothelium. Numerous myelinated and non-myelinated nerve fibrils, as well as nerve endings and mechano-receptors were identified.

Animals↗
PubMed1976

[Dissolution kinetics of synthetic hydroxyapatite and human enamel crystals].

A comparative study of the dissolution of synthetic hydroxyapatite and human enamel crystals has been realized in a buffered (sodium citrate - citric acid) solution in presence of variable quantities of sodium fluoride. The pH of the solutions used was 3.7 and 5.6. The dissolution curves of the synthetic hydroxyapatite and the human enamel crystals were similar. In all cases, the dissolution mechanism was characterized by a first step with a rapid kinetic corresponding to the formation of a central cavity extending parallel to the c axis of the apatite crystal and observed with the electron microscope. In a second stage, the dissolution kinetic was much slower corresponding to a saturation of the buffered solution and an extension of the crystal destruction towards its lateral external surfaces. The dissolution kinetic was faster in a more acidic solution and the total dissolution at a given moment varied inversely to the fluoride amount.

Chemical Phenomena↗
PubMed1975

[Transfer of 45Ca during amelogenesis studied by autoradiography and electron microscopy].

45Ca transfer through the stratum intermedium and the secreting ameloblasts towards enamel has been studied by quantitative electron microscopical autoradiography in tooth-germs of newborn cats following intravenous injection of the isotope. Two transfer pathways were demonstrated. The relatively more important direct path passed through the stratum intermedium and ameloblast intercellular spaces and reached the enamel directly. The second pathway consisted in an intracellular transfer through the ameloblasts. 45Ca penetrated the cell through its basal pole. The mitochondria were the most highly labeled organelles at the different experimental time intervals studied. A maximum of radioactivity was respectively noticed at 30 min and 1 h in the endoplasmic reticulum and the Golgi apparatus. A total absence of silver grains was noted over the secretory ameloblastic bodies. At 6 h, the highest labeling was observed over enamel and especailly over the inner enamel along the enameldentin junction.

Ameloblasts↗
PubMed1975

Ultrastructural gingival reactions to gold foil restorations.

In the case of class-V gold foil restorations prepared below the gingival sulcus in beagle dogs after elevation of a flap, chronic inflammatory changes were observed after 3 weeks in the adjacent epithelium and connective tissue of the gingiva with the presence of dental plaque between the gold restorations and sulcular epithelium. However no inflammation was observed in the junctional epithelium and the subjacent connective tissue 3 weeks after implantation of a gold strip burnished and bounded to the root surface after elevation of a flap. The cell membranes of the superficial epithelial cells were either directly applied to the gold surface or were separated from the latter by an extracellular space about 200 to 500 A in width. No hemidesmosomes were seen. The different responses noted in the two experiments are related to the presence or absence of dental plaque and probably to the surface difference of the gold restorations.

Alveolar Process↗