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A Weinstock

Publications and source records attributed to A Weinstock.

32 records · Page 2Linked to original sources
PubMed1971

Elaboration of the matrix glycoprotein of enamel by the secretory ameloblasts of the rat incisor as revealed by radioautography after galactose- 3 H injection.

The elaboration of enamel matrix glycoprotein was investigated in secretory ameloblasts of incisor teeth in 30-40-g rats. To this end, the distribution of glycoprotein was examined histochemically by the use of phosphotungstic acid at low pH, while the formation of glycoprotein was traced radioautographically in animals sacrificed 2.5-30 min after galactose-(3)H injection. Histochemically, the presence of glycoprotein is observed in ameloblasts as well as in the enamel matrix; in ameloblasts glycoprotein occurs within the Golgi apparatus in amounts increasing from the outer to the inner face of the stacks of saccules, and is concentrated in condensing vacuoles and secretory granules; in the enamel matrix, glycoprotein is observed within linear subunits. Radioautographs at 2.5 min after injection demonstrate the uptake of galactose-(3)H label by Golgi saccules, indicating that galactose-(3)H is incorporated into glycoprotein within this organelle. After 5-10 min, the label collects in the condensing vacuoles and secretory granules of the Golgi region. By 20-30 min, the label appears in the secretory granules of the apical (Tomes') processes, as well as in the enamel matrix (next to the distal end of the apical processes, and at the tips of matrix prongs). In conclusion, galactose contributes to the formation of glycoprotein within the Golgi apparatus. The innermost saccules then distribute the completed glycoprotein to condensing vacuoles, which later evolve into secretory granules. These granules rapidly migrate to the apical processes, where they discharge their glycoprotein content to the developing enamel.

Ameloblasts↗
PubMed1967

The ion-binding characteristics of reconstituted collagen.

The ion-binding capacity of highly purified reconstituted calf-skin collagen, and the effects of these ions on the precipitation and solubility of the collagen, were studied with a variety of salt solutions at ionic strength 0.16 and pH7.4. Only a small percentage of the total theoretically available anionic and cationic groups was available for ion-binding. In view of this, it appears that most of the ionizable groups of collagen are involved in intramolecular or intermolecular linkages, or both. Nevertheless, marked differences in the binding of the various ions by collagen were observed. Bivalent cations were bound in extremely small but remarkably similar quantities. In contrast, sodium was bound both in much higher and more variable quantities. Of the anions, pyrophosphate and sulphate were bound in the largest quantities, followed by phosphate, fluoride and chloride, in that order. Despite the minimal uptake by collagen of bivalent cations, they prevented the aggregation of tropocollagen into fibrils, and disaggregated fibrillar collagen. In the presence of multivalent anions, tropocollagen aggregated readily and its fibrillar stability was maintained. On the basis of the imbalance in the binding of ion pairs by the sodium pyrophosphate- and sodium phosphate-treated collagens, it was apparent that a reduced number of side-chain carboxyl groups were dissociated in the presence of these salts.

Journal Article↗
PubMedDate not supplied

The use of imipenem-cilastatin in neonatal meningitis caused by Citrobacter diversus.

Citrobacter diversus is a cause of severe meningitis in neonates and infants. It is unique in its propensity to produce brain abscesses that play an important role in the poor prognosis associated with this condition. The recommended therapeutic regimen of third-generation cephalosporines, aminoglycosides and trimethoprim-sulfamethoxazole is usually disappointing. We describe the use of imipenemcilastatin in successfully treating Citrobacter diversus meningitis complicated by brain abscesses.

Anti-Bacterial Agents↗
PubMedDate not supplied

Significance of gamma-glutamyl transferase (GGT) activity measurements in alcohol-induced hepatic injury.

Experimental evidence is presented that the determination of gamma-glutamyl transferase (GGT) activity in serum is useful in the assessment of alcohol-induced liver disease and for demonstrating to patients the toxic effects of their drinking habits on the liver. Serial measurements of GGT activity in serum have also proved valuable in monitoring the progress of therapy as well as alleged abstention from alcohol in the known alcoholic.

Adult↗
PubMedDate not supplied

An immediate-extraction anterior single-tooth replacement utilizing a fiber-reinforced dual-component bridge.

Replacement of a single anterior tooth is an extremely challenging procedure. Numerous objective and subjective factors must be evaluated by the interdisciplinary team in the determination of the appropriate restorative method. This article reviews the restorative options and describes an emerging treatment modality--the fiber-reinforced dual-component bridge--as the option selected in a case requiring an immediate extraction of the maxillary right central incisor. The pertinent technology, indications, contraindications, and current clinical technique of dual-component nonmetallic prostheses are examined.

Adult↗