Isolation of beta-lactamase-producing Bacteroides strains associated with clinical failures with penicillin treatment of human orofacial infections

Five patients with orofacial infection which failed to respond to penicillin therapy are described. In each instance, β-lactamase producing Bacteroides strains were found. All strains were resistant to penicillin but sensitive to clindamycin and tinidazole. In two cases, extended surgical treatment cured the patient, but in the other three cases additional clindamycin therapy was required.     

The kinetics and mechanisms of reactions of human tooth enamel in buffered solutions of high fluoride concentrations

The experimental results were quantitatively compared with the theory based on a physical model representing the reaction and with the experiments involving synthetic hydroxyapatite discs. The experimental initial rates self-consistently compared well with the theoretical predictions. An analysis of the experimental initial rate data yielded a reaction constant, κ, for the reaction representing apatite dissolution and calcium fluoride precipitation. It is proposed that the value for κ is a result of both supersaturation with respect to calcium fluoride and undersaturation with respect to apatite at the apatite-calcium fluoride reaction sites. This finding is also consistent with the analysis of the experiments with synthetic apatite discs.Important similarities and significant differences were found between the experiments with the enamel sections and with synthetic apatite discs. The experiments with the synthetic apatite discs were reported to proceed “normally” as predicted by the physical model over the entire course of the reaction. In contrast to these findings, while the initial rates of the enamel-fluoride reaction were found to proceed relatively rapidly and according to the theoretical predictions, the rates at later times were drastically reduced. This “choking off” was observed to be most severe in the experiments at low pH and high fluoride concentrations, and little or no “choking oft” was observed at low fluoride concentrations and high pH.     

Dermatography, a treatment for sequelae after head and neck surgery: a case report.

Two patients with discolouration fo skin grafts after head and neck surgery, were treated with dermatography, a refined method of tattooing, and with intra-cicatricial keloidectomy, of which the results are described.