PubMed · 264826
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R L Levy, P Weinstein, P Milgrom. 1977. Behavioral guidelines for plaque control programs.. https://pubmed.ncbi.nlm.nih.gov/264826/
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The design of clinical trials aimed at treating different types of periodontal diseases must take into account the prevalence of the disease in the population and the relationship of various descriptors, which may vary from disease to disease. For screening purposes, patients should be selected with disease in the high-severity range, in order to maximize the likelihood of detecting a therapeutic effect. Subsequent trials may be designed around a more representative group of subjects. Therapies must be evaluated on the basis of actual clinical changes, rather than their effect on presumed etiologic factors. The observed changes must be of clinical as well as statistical significance. The distribution of periodontal diseases within a dentition may affect as few as one or as many as over one hundred sites. Strategies are needed to correlate events observed at sites within the dentition, i.e. tooth surface-based measurements or scores, with events that are subject-based, e.g. concentration of blood or salivary components.
pH activity profiles and inhibitor sensitivities were compared for membrane ATPases isolated from three oral lactic acid bacteria, Lactobacillus casei ATCC 4646, Streptococcus mutans GS-5, and Streptococcus sanguis NCTC 10904, with, respectively, high, moderate, and low levels of acid tolerance. Membranes containing F1F0 ATPases were isolated by means of salt lysis of cells treated with muralytic enzymes. Membrane-free F1F0 complexes were then isolated from membranes by detergent extraction with Triton X-100 or octylglucoside. Finally, F1 complexes free of the proton-conducting F0 sector were obtained by washing membranes with buffers of low ionic strength. The pH activity profiles of the membrane-associated enzymes reflected the general acid tolerances of the organisms from which they were isolated; for example, pH optima were approximately 5.5, 6.0, and 7.0, respectively, for enzymes from L. casei, S. mutans, and S. sanguis. Roughly similar profiles were found for membrane-free F1F0 complexes, which were stabilized by phospholipids against loss of activity during storage. However, profiles for F1 enzymes were distinctly narrower, indicating that association with F0 and possibly other membrane components enhanced tolerance to both acid and alkaline media. All of the enzymes were found to have similar sensitivities to Al-F complexes, but only F1F0 enzymes were highly sensitive to dicyclohexylcarbodiimide. The procedures described for isolation of membrane-free F1F0 forms of the enzymes from oral lactic acid bacteria will be of use in future studies of the characteristics of the enzymes, especially in studies with liposomes.