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Biomedical subjects

W G Wade

Publications and source records attributed to W G Wade.

At least 55 records · Page 3Linked to original sources

A comparison of delmopinol and chlorhexidine on plaque regrowth over a 4-day period and salivary bacterial counts.

Delmopinol has been considered as a potential agent for the chemical control of plaque. The aims of these studies were to measure the effects of a 0.2% delmopinol hydrochloride mouthrinse on (1) plaque reformation and (2) salivary bacterial counts. Comparisons were made with a 0.2% chlorhexidine rinse and a placebo rinse. A group of 12 male volunteers took part in the plaque study which was of a double blind, randomised, 3 cell, cross-over design. From a zero plaque baseline subjects rinsed, 2x a day, under supervision, for 1 min with 10-ml volumes of the allocated rinse. After 4 days, during which no other form of oral hygiene was performed, plaque was scored by area and index. Plaque results were significantly lower with chlorhexidine and delmopinol compared with control, and with chlorhexidine compared to delmopinol. Side-effects with delmopinol were transient tingling and numbness of the tongue in some subjects. A 2nd group of 12 male volunteers received single, 1-min rinses of the 3 formulations. Salivary bacterial counts were determined immediately before and up to 420 min after rinsing. Compared to the control rinse, chlorhexidine significantly reduced bacterial counts of 420 min. Delmopinol produced a small reduction in bacterial counts which was only significantly different from control at one time point. Delmopinol deserves further evaluation as a chemical plaque inhibitor, particularly when used as an adjunct to normal toothcleaning.

Adult↗

In vitro activity of meropenem and other agents against oral bacteria.

The susceptibility of 106 oral bacteria to meropenem, a new carbapenem antimicrobial, penicillin V, tetracycline and metronidazole was assessed by an agar dilution method. Meropenem was the most effective of the antimicrobials, with all strains tested being inhibited at < or = 1 mg/l. A number of strains were resistant to penicillin V, particularly Bacteroides gracilis, and tetracycline resistance was widespread amongst the streptococci tested. Metronidazole was extremely effective against obligate anaerobes. The results of this study suggest that meropenem has potential for use in the treatment of serious head and neck infections.

Anti-Bacterial Agents↗

Antibacterial activity of some triclosan-containing toothpastes and their ingredients.

The antibacterial activity of 4 triclosan-containing toothpastes was compared to a conventional fluoride dentifrice and triclosan and sodium lauryl sulphate (SLS), both singly and in combination. A panel of 17 bacteria was tested by an agar dilution method. At concentrations typical of those found in toothpastes, triclosan and SLS displayed approximately equal antibacterial activity. A paste containing triclosan and zinc citrate appeared more active than the other triclosan pastes which, in general, showed marginal superiority over the conventional paste. SLS, although included in dentifrice formulations for its detergent properties, may significantly contribute to the antibacterial profile of a product. The need for appropriate controls when evaluating experimental toothpastes is emphasized.

Aggregatibacter actinomycetemcomitans↗

Bacteroides ureolyticus (NTU) medium for the selective recovery of Bacteroides gracilis.

Bacteroides gracilis is a gram-negative anaerobic bacillus which requires formate and fumarate for growth; it has been implicated in periodontal disease and serious infections of the head and neck. In this study, Bacteroides ureolyticus (NTU) medium was tested for its ability to allow the growth of B. gracilis and other formate-fumarate requiring gram-negative anaerobes and to enable the recovery of these organisms from clinical specimens. All reference strains grew on NTU medium with the exception of Wolinella recta and formate-fumarate requiring organisms were isolated from 18 of 20 samples of subgingival dental plaque from patients with chronic periodontitis. B. gracilis was the commonest species isolated (14 of the 29 isolates); B. ureolyticus was not found.

Bacteroides↗

Predominant cultivable flora in pericoronitis.

The predominant cultivable flora in pericoronitis was investigated by culturing pus from affected sites in 20 patients. Twenty colonies were picked at random from non-selective plates and identified using conventional biochemical and physiological tests, analysis of metabolic end-products by gas chromatography and protein profile analysis. The most frequently isolated organisms were Prevotella (Bacteroides) intermedia, Peptostreptococcus micros, Veillonella species, Fusobacterium nucleatum and Streptococcus mitis. Porphyromonas (Bacteroides) gingivalis was not isolated and asaccharolytic Eubacterium species were virtually absent. The predominant cultivable microflora in pericoronitis was found to be highly anaerobic in nature and superficially similar to that found in chronic periodontitis, although proposed marker organisms of severe periodontitis were absent.

Adolescent↗

Comparison of identification methods for oral asaccharolytic Eubacterium species.

Thirty one strains of oral, asaccharolytic Eubacterium spp. and the type strains of E. brachy, E. nodatum and E. timidum were subjected to three identification techniques--protein-profile analysis, determination of metabolic end-products, and the API ATB32A identification kit. Five clusters were obtained from numerical analysis of protein profiles and excellent correlations were seen with the other two methods. Protein profiles alone allowed unequivocal identification.

Bacterial Proteins↗

Protein profiles of Capnocytophaga species.

Ninety-seven strains of Capnocytophaga isolated from the oral cavity and the type strains of C. ochracea, C. sputigena and C. gingivalis were compared by one-dimensional SDS-PAGE of whole cell proteins. The protein patterns were highly reproducible and were used as the basis for numerical taxonomic analysis. The clusters containing the type strains of C. ochracea and C. sputigena segregated at the 78% similarity level. Some of the eight clusters obtained at this level showed good correlation with grouping based on the results of biochemical testing for lactose and galactose fermentation and nitrate reduction. No consistent association was found between protein profiles and colony type, size or colour or cell length but all agar-adherent colony types segregated into a single cluster.

Bacterial Proteins↗

A rapid, semi-automated SDS-PAGE identification system for oral anaerobic bacteria.

SDS-polyacrylamide gel electrophoresis is a useful technique in bacterial differentiation and identification. A rapid, semi-automated SDS-PAGE system (Phast System) was assessed for identification of formate-fumarate-requiring, asaccharolytic, Gram-negative oral anaerobes. The system permitted loading, separation and staining of gels within 2 h. Percentage similarities between strains were determined using correlation coefficients and cluster analysis. The protein profiles were sufficiently reproducible provided that distorted profiles were disregarded. Strains were successfully separated into their species, with the exception of Bacteroides ureolyticus NCTC 10939, which appeared to be distinct from other strains of that species. Twenty-nine unidentified formate-fumarate-requiring, sub-gingival plaque strains were suitably clustered with the standard strains as verified by a series of physiological and biochemical tests.

Bacterial Proteins↗

Comparison of solid media for cultivation of anaerobes.

Two commercial agar media for the cultivation of anaerobes were compared with four other media for their ability to support the growth of a wide range of anaerobes from clinical specimens of subgingival plaque. Fastidious anaerobe agar (FAA, Lab M) and anaerobe agar (GAA, Gibco) allowed better growth of the pure cultures than the other media. FAA recovered the highest numbers of bacteria from subgingival plaque specimens which were composed predominantly of anaerobes. GAA performed poorly with these samples. It is concluded that FAA seemed to be superior to the other media tested for the cultivation and recovery of anaerobes.

Agar↗

In-vitro activity of ciprofloxacin and other agents against oral bacteria.

The susceptibility of 102 bacterial strains isolated from oral infections to ciprofloxacin, penicillin V, tetracycline and metronidazole was assessed by an agar dilution technique. Penicillin V was the most effective of the antimicrobials, with only three isolates resistant, while widespread resistance to tetracycline was seen. Metronidazole, as expected, was extremely effective against anaerobic isolates. Ciprofloxacin exhibited intermediate activity with the majority of MICs in the range of 1-4 mg/l. However, resistance was seen, particularly among Actinomyces and Wolinella species. In was concluded that, on the basis of these results, ciprofloxacin has limited potential for the treatment of oral infection but its potential for use in prophylaxis in head and neck surgery remains to be determined.

Bacteria↗

Frequency and density of yeasts in the mouths of malnourished children.

The prevalence and density of yeasts and Candida albicans on the buccal mucosa and dorsum of the tongue have been assessed in 106 children in Crossroads squatter camp, South Africa. They were divided into a malnourished and a control group on the basis of an age/weight chart. No differences were found in yeast prevalence and density in the two groups. However, malnourished children more frequently had a mucosal density of yeasts, and particularly C. albicans, exceeding the upper limit normally found in health, in the absence of clinical infection. Some evidence was found to suggest that yeast density might be influenced by sex as well as nutritional status.

Candida albicans↗

In vitro activity of a chlorhexidine-containing mouthwash against subgingival bacteria.

Three hundred and fifteen subgingival isolates were tested for their susceptibility to a mouthwash containing 0.2% chlorhexidine. The majority of strains tested were susceptible at high dilution although some strains of S. mitior, S. sanguis, and Capnocytophaga were relatively resistant. It was concluded that, on the basis of these in vitro results, the mouthwash should have potential for subgingival use in the treatment of chronic periodontitis.

Bacteria↗

Comparison of in vitro activity of niridazole, metronidazole and tetracycline against subgingival bacteria in chronic periodontitis.

Niridazole, metronidazole and tetracycline were compared for their activity against subgingival bacteria from patients with chronic periodontitis. Niridazole was consistently more effective than the other drugs against obligate anaerobes and exhibited some activity against facultative organisms. It was concluded that niridazole has potential for topical use in chronic periodontitis.

Bacteria, Anaerobic↗

The early bacterial colonization of acrylic palates in man.

Adhesive tape applied to the fitting surface was used to study the early colonization of acrylic palates in six subjects. Streptococci were major constituents of the plaque accumulated on the tape over the first 3 days. Bacterial colonization of the tape discs was selective in that dextran-producing streptococci constituted a greater proportion of the total streptococcal count after 15 min compared with that of the initial sample and saliva, while the converse was true for Streptococcus salivarius. Scanning electron microscopy showed that denture plaque development started in grooves and depressions on the surface of the tape, and became more extensive with time. Comparison of the colonization of tape and acrylic discs in one individual demonstrated that the tape was a suitable model for in vivo colonization of dentures or orthodontic appliances.

Adhesives↗

Class-specific antibodies to Streptococcus mutans in human serum, saliva and breast milk.

Previous techniques used for the detection and quantitation of antibodies in body fluids may be inappropriate where only small volumes are available, or may not be sensitive enough to detect low levels of specific antibodies. An indirect ELISA technique has successfully been employed to estimate class-specific antibody levels to Streptococcus mutans in serum and secretions in a group of mothers and their neonates, and an attempt has been made to relate such levels to the presence or absence of active caries in the mothers. A high maternal serum IgG antibody level appears to exert a protective effect against dental caries. Antibody levels in maternal saliva and colostrum/breast milk showed no differences between the 2 groups. The presence of active caries in mothers was associated with an elevated IgA antibody level in neonatal saliva. Although ELISA permitted the detection of low levels of antibody in the small volumes of neonatal saliva collected, a further increase in sensitivity and specificity of the assay would be advantageous.

Antibodies↗

An improved medium for isolation of Streptococcus mutans.

A medium based upon tryptone, yeast extract, cystine (TYC) agar and incorporating bacitracin and sucrose has been evaluated for selective isolation of Streptococcus mutans. The effect of varying the concentrations of sucrose and bacitracin on the recovery of two standard strains was investigated. Growth of S. mutans NCTC 10449 was significantly inhibited by increasing concentrations of sucrose but was not affected by bacitracin; the reverse was seen with S. sobrinus strain 6715. The best compromise between recovery of the streptococci and growth of other organisms was obtained with a final sucrose concentration of 20% and bacitracin 0.2 units/ml. In comparison with three other selective media, this medium gave the highest recovery rate of standard strains, indicating that it is superior to mitis-salivarius bacitracin (MSB) agar for the recovery of S. mutans from saliva.

Adult↗