The effect of introduction of a guideline on the management of vaginal discharge and in particular bacterial vaginosis in primary care.

BACKGROUND: Bacterial vaginosis (BV) is the commonest cause of vaginal discharge, and its association with obstetric and gynaecological complications is being recognized increasingly. It was our impression that BV was poorly understood and underdiagnosed in family practice. OBJECTIVE: The aim of this study was to explore the management of patients with vaginal symptoms by family practitioners and to see if the management changed after the assimilation of best practice guidelines. METHOD: Family practitioners were invited to complete a baseline questionnaire of their perceived practice, and to record actual practice when consulted about vaginal symptoms, for a minimum of 4 weeks. Consensus best practice guidelines were then provided and practice recorded for a similar period. RESULTS: Baseline data was received from 34 practitioners and suggested that the symptoms and signs of different vaginal infections were not well known. Most symptomatic patients were only investigated at re-presentation with unresolved symptoms or at recurrence, and 43% of respondents treated with empirical antifungals as a first line approach. Pregnant patients were only occasionally asked about symptoms and only occasionally examined if symptomatic. Pre-guideline practice data from 30 practitioners showed 1.2 patient consultations/week, of which 60% were examined and 55% had a high vaginal swab (HVS) sent. Only 2% had near-patient tests done. Post-guideline data from 23 family practitioners showed a lower recorded consultation rate at 0.7/week, but 90% of these were examined, 77% had an HVS sent and 69% had near-patient tests done. Of the 36 HVS examined by Gram stain, 19 (53%) showed Lactobacillus predominant flora and 10 (28%) suggested BV. Seven (19%) were borderline or ungradable. Only three (8%) showed yeasts, one of which also showed BV. CONCLUSIONS: Baseline data supported our impression that BV was under-recognized. Guidelines appeared to improve the rate of investigation of women consulting with vaginal symptoms.

A specific DNA sequence is required for high frequency of recombination in the ade6 gene of fission yeast.

The point mutation M26 in the ade6 gene of Schizosaccharomyces pombe increases recombination frequency by an order of magnitude in comparison with other mutations in the same gene. The hypothesis is tested that this hot spot of recombination requires a specific nucleotide sequence at the M26 site. The DNA sequence is altered systematically by in vitro mutagenesis, and the resulting sequences are introduced into the ade6 gene in vivo by gene replacement. It results that any change of the heptanucleotide ATGACGT leads to loss of high frequency of recombination. Thus this oligonucleotide sequence is necessary for high frequency of recombination, but it seems not to be sufficient.

Glycosylation of bacterial cellulases prevents proteolytic cleavage between functional domains.

Glycosylated cellulases from Cellulomonas fimi were compared with their non-glycosylated counterparts synthesized in Escherichia coli from recombinant DNA. Glycosylation of the enzymes does not significantly affect their kinetic properties, or their stabilities towards heat and pH. However, the glycosylated enzymes are protected from attack by a C. fimi protease when bound to cellulose, while the non-glycosylated enzymes yield active, truncated products with greatly reduced affinity for cellulose.

Sequence conservation and region shuffling in an endoglucanase and an exoglucanase from Cellulomonas fimi.

Cellulomonas fimi produces an endoglucanase and an exoglucanase which bind strongly to cellulose. Each enzyme contains three distinct regions: a short sequence of about 20 amino acids containing only proline and threonine (the Pro-Thr box); an irregular region, rich in hydroxyamino acids, of low charge density, and which is predicted to have little secondary structure; and an ordered region of higher charge density which contains a potential active site, and which is predicted to have secondary structure. The Pro-Thr box is conserved almost perfectly in the two enzymes. The irregular regions are 50% conserved, and the conserved sequences include four Asn-Xaa-Ser/Thr sites. The ordered regions appear not to be conserved, but the potential active sites both have the sequence Glu-Xaa7-Asn-Xaa6-Thr; they occur at widely separated sites in the two regions. The order of the regions is reversed in the two enzymes: irregular-Pro-Thr box-ordered in the endoglucanase; ordered-Pro-Thr box-irregular in the exoglucanase. The genes for the two enzymes appear to have arisen by shuffling of two conserved sequences and either one or two other sequences.

Mode of action and substrate specificities of cellulases from cloned bacterial genes.

Three recombinant plasmids, pEC1, pEC2, and pEC3, each containing a unique Cellulomonas fimi chromosomal DNA insert, expressed Cm-cellulase activities in Escherichia coli C600 (Whittle, D. J., Kilburn, D. H., Warren, R. A. J., and Miller, R. C., Jr. (1982) Gene (Amst.) 17, 139-145; Gilkes, N. R., Kilburn, D. G., Langsford, M. L., Miller, R. C., Jr., Wakarchuk, W. W., Warren, R. A. J., Whittle, D. J., and Wong, W. K. R. (1984) J. Gen. Microbiol. 130, 1377-1384). Viscometric and chemical analyses showed that the enzymes encoded by pEC2 and pEC3 behaved as endoglucanases, whereas that encoded by pEC1 behaved as an exoglucanase. The activities of the exoglucanase and the pEC2-encoded endodglucanase were additive on Cm-cellulose as substrate. The pEC1-encoded enzyme also hydrolyzed xylan and p-nitrophenyl cellobioside. Two substrate-bound Cm-cellulases were isolated from the residual cellulose in a C. fimi culture by guanidine hydrochloride elution, affinity chromatography, and polyacrylamide gel electrophoresis. Both were glycoproteins of apparent Mr = 58,000 and 56,000, respectively. The 56-kDa enzyme appeared to be identical with the pEC1-encoded product, suggesting that they arise from the same gene.