No abstract

Fresh isolates of Streptococcus mutans, Streptococcus sanguis, and Streptococcus salivarius from human dental plaque were all highly hydrophobic. After repeated subculture in vitro on blood agar, strains of S. mutans serotype c showed decreased hydrophobicity, whereas serotype dlg strains did not. Parallel to the decreased hydrophobicity in the serotype c strains, an impaired ability to adhere to hydroxyapatite was observed. A similar but less pronounced decrease in

Pharmacokinetic and pharmacodynamic properties of a new controlled-release (CR) formulation of metoprolol have been compared with those of atenolol. Metoprolol CR (100 mg and 200 mg), atenolol (50 mg and 100 mg) and placebo were each given once daily for four days in a double-blind, cross-over study to ten healthy men. The plasma concentration-time profiles were more even with metoprolol CR than with atenolol over the 24-h dose interval, shown by the lower fluctuation ratio and the longer time period during which the plasma concentration exceeded 50% of the maximum concentration. All four active treatment regimens reduced exercise heart rate over the 24-h period compared with placebo. However, the reduction in both exercise heart rate and systolic blood pressure (SBP) was more even with metoprolol CR than with atenolol. The remaining beta 1-blockade after 24 h, expressed as the percentage reduction in exercise heart rate in relation to placebo, was significantly greater after the administration of metoprolol CR, 200 mg, than after either dose of atenolol. At this time the beta 1-blockade with metoprolol CR, 100 mg, was similar to that with atenolol, 100 mg. At peak plasma concentrations, 4 h after the dose, the subjects experienced less fatigue during exercise with metoprolol CR than with atenolol.

This paper describes the effects of the thiol compounds glutathione and N-acetylcysteine and the seleno-organic agent Ebselen on the development of Sephadex-induced lung edema and cell infiltration in the rat. Neither thiol had any effect upon the development of the edema when administered in large, repeated doses. In contrast, when Ebselen was co-administered with the thiols, there was a dose-dependent inhibition of the development of the edema, but lung weights could not be returned to normal values. However, when the thiols were omitted and Ebselen was administered alone, the development of the edema was totally blocked. In addition, in Ebselen-only treated animals there was a selective inhibition of the infiltration of lymphocytes, basophils and eosinophils into the lung lumen without affecting the populations of macrophages and neutrophils. Again, the Ebselen-induced effect was reduced by coadministration of either thiol. These findings are discussed in terms of the potential mechanism of action of Ebselen in vivo and of the possibility of Ebselen being of therapeutic potential in cases of diffuse pulmonary inflammation in humans.

– Three chlorhexidine‐sensitive strains of Streptococcus sanguis developed resistance to chlorhexidine when grown as continuous cultures in a fermenter containing medium with increasing concentrations of the drug. The MIC of the test strains increased by between two and three dilution steps and these high values were maintained after daily transfer in drug‐free medium for at least 15 d. In addition, the resistance of one of the strains persisted for more than 1 month of continuous growth in drug‐free medium in the fermenter. DNA from the resistant (Chx1) variants of the three strains transformed competent sensitive S. sanguis to increased chlorhexidine resistance, thus proving that resistance to this drug is an inheritable trait. Immunoelectrophoretic experiments showed that certain changes in the antigenic pattern of the Chx1 variants had occurred as compared with their sensitive wild‐type strains. Antigen extracts of the Chx1 variants and all Chx1 recombinants tested contained consistently less protein than those of the sensitive wild‐types.