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Biomedical subjects

R C Oliver

Publications and source records attributed to R C Oliver.

9 recordsLinked to original sources
PubMed1977

Patient evaluation.

Failure to diagnose periodontal disease is a frequent and unnecessary error. A new periodontal screening examination has been proposed that will accurately detect periodontal disease in approximately five minutes and can be incorporated into a routine dental examination. Simplified treatment planning based on the findings of the periodontal screening examination has also been proposed. Its use could significantly improve the quality of periodontal care for most dental patients.

Adolescent↗
PubMed1977

Changes in the surface properties of rabbit polymorphonuclear leucocytes, induced by bacteria and bacterial endotoxin.

Rabbit peritoneal polymorphonuclear leucocytes were induced to aggregate by a variety of bacterial species. In the absence of serum, Gram-negative bacteria were more effective at inducing aggregation than Gram-positive. The most effective micro-organism tested, Acinetobacter sp. 199A, was readily phagocytosed and also induced extracellular secretion of the granule enzymes peroxidase and lysozyme. Isolated endotoxin from this bacterial species was highly effective in inducing aggregation and granule enzyme release. Endotoxin-induced aggregation was associated with a large increase in the amount of lactoperoxidase-catalysed iodination of surface protein. Only one iodinatable protein was detected, of molecular weight 150 000. It is postulated that phagocytosis of Gram-negative bacteria, followed by granule enzyme release, accelerates the rate of membrane recycling and that this brings new adhesive protein to the surface more rapidly.

Animals↗
PubMed1977

Endotoxin-induced platelet aggregation and secretion. II. Changes in plasma membrane proteins.

Responses of blood platelets to bacterial endotoxin lipopolysaccharide (LPS) have been correlated with changes in the molecular organization and composition of the platelet plasma membrane proteins. Binding of LPS, which occurred in the absence of Ca2+, was distinguished from platelet aggregation and degranulation, which required Ca2+ and plasma proteins. Changes in membrane organization were detected by double-labelling with [125I] and [131I] iodide, mediated by lactoperoxidase and hydrogen peroxide. Changes in total membrane composition were detected by gel electrophoresis of isolated membranes. Binding of LPS was associated with increased accessibility of a protein of mol. wt. 80000 to iodination. After aggregation and degranulation there was, in addition, increased accessibility of proteins of mol. wt. 68000 and 48000. Isolated membranes from LPS-stimulated platelets contained more of a protein of mol. wt. 200000 and less of a protein of mol. wt. 220000 than control membranes prepared from unstimulated platelets in the presence of cAMP and aminophylline. The relationship of the modified plasma membrane proteins to the contractile proteins of the platelet and their possible redistribution in the cell during aggregation and secretion is discussed.

Acinetobacter↗
PubMed1976

Lysis and killing of bacteria by lysosomal proteinases.

The bacteriolytic and bactericidal effects of the human proteinases cathepsin B, cathepsin D, cathepsin G, and elastase were investigated. Cathepsin G and elastase were 5 to 10% as active as egg white lysozyme in the lysis of Micrococcus lysodeikticus. All four enzymes slowly lysed the lysozyme-resistant Staphylococcus aureus. The gram-negative Acinetobacter 199A was rendered sensitive to lysozyme by all of the proteinases. Only elastase caused marked proteolysis of the outer membrane, which would permit access by lysozyme to the underlying peptidoglycan. When the surface layer of regularly arranged a protein was removed, however, the outer membrane proteins became susceptible to the other proteinases. Cathepsin G, elastase, and cathepsin D were bactericidal to Acinetobacter 199A. The bactericidal activity of cathepsin D was shown to be dependent on enzymatic activity, unlike that of cathepsin G, which was related to its cationic nature.

Acinetobacter↗
PubMed1976

Synthesis and turnover of the regularly arranged surface protein of Acinetobacter sp. relative to the other components of the cell envelope.

The formation of the components of the cell envelope of Acinetobacter sp. 199A was investigated by measuring the incorporation of [3H]leucine into protein, [14C]galactose into lipopolysaccharide, 32P into phospholipid, and [3H]diaminopimelic acid into peptidoglycan. Whereas the lipopolysaccharide and intrinsic protein of the outer membrane were stable, some of the regularly arranged surface protein, the alpha-protein, was lost into the growth medium. Only newly synthesized alpha-protein was lost. The peptidoglycan of the murein layer was also labile. Selective inhibition of the formation of individual components of the cell envelope with penicillin, chloramphenicol, and bacitracin showed that incorporation of protein into the outer membrane required the simultaneous formation of complete lipopolysaccharide. The converse was not true: protein synthesis was not required for lipopolysaccharide incorporation. Formation of the outer membrane and the murein layer proceeded independently.

Acinetobacter↗
PubMed1976

A periodontist's view on the assessment of periodontal disease in the community.

Periodontal treatment differs from other forms of dental treatment in that it demands long term cooperation from the patient without which the dentists' efforts are largely without value. The earliest stage of periodontal disease is gingivitis which is characterized by bleeding on gentle probing. It is a reversible condition which, depending on many poorly understood factors, may or may not progress to periodontal disease. This stage is characterized by the apical migration of junctional epithelium, pocket formation and loss of alveolar bone. Pocket depth, though not indicating the presence of active disease, is the best available measure of periodontal disease. In school children the majority of disease is gingivitis which can be largely eliminated by plaque control which they should be taught to practise from themselves. In adults a screening procedure has been developed which will rapidly identify those in need of treatment. Patients with gingivitis can be referred to hygienists. Those with moderately advanced disease are scheduled for non-surgical periodontal therapy which should be followed by re-evaluation and redefinition of the treatment plan. Those with advanced periodontal disease are usually referred for specialist treatment. It has been shown that pockets of up to 5 mm in depth can be maintained without further destruction by plaque control combined with scaling and root planing. The most important aspect of periodontal health remains the quality of long term maintenance care and the motivation of the patient to accept responsibility for it.

Adolescent↗