Clinical indicators of mycobacteraemia in adults admitted to hospital in Blantyre

The aims of the study were to measure the prevalence and outcome of mycobacteraemia in febrile hospitalised adults; to determine what proportion could be identified using routine methods; to assess clinical indicators of mycobacteraemia and the usefulness of a diagnostic trial of anti-TB treatment. We prospectively examined adults with fever or a history of fever admitted to adult medical wards of QECH, Blantyre. All had blood cultured for bacteria and mycobacteria, chest x-ray and sputum smears. M. tuberculosis was the commonest blood isolate, affecting 57 of 344 patients (17%). In 44 (77%) patients with mycobacteraemia, TB was identified using routine investigations; in only 6 (11%) it was not suspected. Strong clinical indicators of mycobacteraemia were anaemia, HIV seropositivity, cough, chronic fever, and a clinical diagnosis of AIDS on the day of admission. Of nine patients selected for a therapeutic trial of TB treatment, six had mycobacteraemia, of whom five died during the trial. Mortality on short course chemotherapy on the TB ward after one month, was similar whether patients had mycobacteramia (21%) or not (32%). TB can be identified with routine methods in most patients with mycobacteraemia. If treated, mycobacteraemia has as good an early outcome as TB without mycobacteraemia. Strengthening of basic facilities is likely to improve detection and treatment of mycobacterial disease.     

Vertebral bone density in children: effect of puberty

To determine changes in bone density during growth, trabecular vertebral density and an index of spinal cortical bone were measured with quantitative computed tomography in 101 children. The children were divided by age into three groups: prepubertal, indeterminate, and pubertal. Compared with prepubertal children, pubertal adolescents had significantly higher trabecular bone density and more compact bone in the spine (P less than .001). After controlling for puberty, vertebral bone density failed to correlate significantly with age, sex, weight, height, surface area, and body mass index. The results indicate that bone density increases markedly during puberty.     

Esophageal anastomotic leaks: preliminary results of treatment with balloon dilation

Disruption of a cervical esophagogastric or esophagocolonic anastomosis shortly after surgery is a common complication, and fistula drainage from the leaking anastomosis may be prolonged. Narrowing of the anastomosis apparently contributes to the development and maintenance of the fistula. Fluoroscopically guided balloon dilation of anastomotic strictures was performed in three patients with anastomotic leaks. Preliminary results suggest that the procedure is safe and promotes healing of the fistula.     

Branhamella catarrhalis: antibiotic sensitivities and beta-lactamases

Twenty-eight strains of Branhamella catarrhalis, isolated from patients with acute exacerbations of chronic bronchitis, were tested both for beta-lactamase production and for sensitivity to a wide range of antimicrobial agents. A microtitre broth dilution technique was used for the latter and the MIC50, MIC90, and geometric mean MIC values were all calculated. Eleven strains were found to produce beta-lactamases. Isoelectric focusing in polyacrylamide gels showed four different band patterns, of which the most common was identical with that of the Ravasio type enzyme. Substrate profiles of the four types of branhamella beta-lactamases differed from each other although one was again similar to the Ravasio enzyme profile. Most of these beta-lactamases were readily inhibited by clavulanic acid (with I50 values of 0.01-0.08 mg/l) but were less readily inhibited by oxacillin. Attempts to isolate extrachromosomal DNA were unsuccessful. These results suggest that at least five possible different beta-lactamases can be demonstrated in Bran. catarrhalis strains, and that they are chromosomally determined.     

Effect of platelet-activating factor (PAF) on human platelets

The effect of pure synthetic PAF (1-0-alkyl-2-acetyl-sn-glycero-3- phosphorylcholine) was studied in human platelets. PAF (0.2--2.0 micrograms/ml) produced a dose-dependent aggregation in human platelet- rich plasma (PRP) or platelet suspension obtained by gel-filtration (GFP). In addition, PAF (0.8 microgram/ml) induced secretion of 14C- serotonin (45% +/- 10%; mean +/- SD, n = 9) and platelet factor 4 (PF4) (12.89 +/- 3.81 micrograms/10(9) platelets; n = 9) in PRP. Similar results were obtained in GFP. Aggregation and release of 14C-serotonin and PF4 were inhibited by the metabolic inhibitors 2-deoxyglucose (16.7 mM) and antimycin-A (8.3 micrograms/ml), by the membrane-active drugs mepacrine (10 microM) and chlorpromazine (0.025 mM), by PGI2 (5.34 nM), which elevates intracellular c-AMP, by indomethacin (10 microM) or aspirin (100 microM). The ADP scavengers, creatine phosphate and creatine phosphokinase (CP/CPK), inhibited the second wave of aggregation but not secretion. These data suggest that the major effect of PAF on human platelets is mediated through the cyclo-oxygenase pathway and not through a third pathway.     

Comparison of different tobramycin assays.

Three commercial available tobramycin assays, the fluorescent immunoassay (AMES), the Diagnostic Products Corp. radioimmunoassay, and the Nuclear Medical System radioimmunoassay, were compared with the microbiological assay and the chemical assay involving high-performance liquid chromatography. The results obtained with each assay were evaluated in terms of usefulness, reproducibility, and cost-effectiveness.