Sensitivity to carbenicillin and ticarcillin, and the beta-lactamases of Pseudomonas aeruginosa in the UK in 1978-79

A total of 438 strains of Pseudomonas aeruginosa supplied by 10 hospitals in the UK reporting an increase in resistance to carbenicillin was tested for sensitivity to carbenicillin and ticarcillin. It was found that 85% of the strains were inhibited by 125 microgram carbenicillin/ml and 87% by 50 microgram ticarcillin/ml, and that ticarcillin was from two- to four-fold more active than carbenicillin against the majority of these strains. Strains with a high level of resistance to carbenicillin (MIC greater than 1000 microgram/ml) possessed constitutive beta-lactamases, and five different types of enzyme were identified. There was good correlation between minimum inhibitory concentrations and the results of disc sensitivity tests in this study, 82% with the 100 microgram carbenicillin disc and 90( with the 75 microgram ticarcillin disc, but results reported in the hospital laboratory tests with the carbenicillin disc were less satisfactory (64% correlation). From a comparison with data reported in 1967 there does not appear to have been a significant increase in the incidence of carbenicillin-resistant strains of Ps aeruginosa in the UK.

Muramic acid as a measure of microbial biomass in estuarine and marine samples

Muramic acid, a component of the muramyl peptide found only in the cell walls of bacteria and blue-green algae, furnishes a measure of detrital or sedimentary procaryotic biomass. A reproducible assay involving acid hydrolysis, preparative thin-layer chromatographic purification, and colorimetric analysis of lactate released from muramic acid by alkaline hydrolysis is described. Comparison of semitropical estuarine detritus, estuarine muds, and sediments from anaerobic Black Sea cores showed muramic acid levels of 100 to 700 microng/g (dry weight), 34 microng/g, and 1.5 to 14.9 microng/g, respectively. Enzymatic assays of lactate from muramic acid gave results 10- to 20-fold higher. Radioactive pulse-labeling studies showed that [14C]acetate is rapidly incorporated into muramic acid by the detrital microflora. Subsequent loss of 14C, accompanied by nearly constant levels of total muramic acid, indicated active metabolism in procaryotic cell walls.

Benign hemangiomyoma of the uterus

A benign cavernous hemangiomyoma of the uterus in a 52-year-old woman is described. The tumor consisted of large venous channels within a stroma composed chiefly of smooth muscle and was confined to the corpus, without involvement of the endometrium or cervix. Considerable thrombosis had occurred within the vascular spaces. Hemangiomas of the uterus are very uncommon and the great majority are benign. A classification of uterine hemangiomas is presented, together with a discussion of their histogenesis and their relation to malformations.

Method for the clinical evaluation of enamel polish

Enamel polish of 600 children was scored. The method used is simple and comprises a visual comparison of the facial surfaces of incisors with a polish standard prepared by selectively polishing extracted teeth. Examiners with little experience can distinguish degrees of enamel polish. A high-polish dentifrice produced significantly greater enamel polish during the 27-month study. A "polish" with flour of pumice at the beginning of the study did not influence this enamel polish.

A note on the microscopic structure of enamel

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