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Biomedical subjects

T W MacFarlane

Publications and source records attributed to T W MacFarlane.

At least 91 records · Page 5Linked to original sources
PubMed1986

Phospholipase activity as a criterion for biotyping Candida albicans.

The phospholipase activity of 100 oral isolates of Candida albicans was determined by a plate assay. 94% of the C. albicans isolates were phospholipase producers with varying degrees of activity ranging from Pz values of 0.3 to 0.9. As variations in the degree of phospholipase activity on repeat testing of isolates was high it is concluded that the latter criterion cannot be usefully incorporated into a biotyping system of C. albicans.

Candida albicans↗
PubMed1985

Effect of chlorhexidine gluconate on the adherence of Candida species to denture acrylic.

The effect of pretreatment of denture acrylic with chlorhexidine gluconate on the subsequent adherence of Candida albicans GDH 2346 was measured in vitro. Adherence was significantly reduced by pretreatment with chlorhexidine; maximal inhibition was achieved by incubation at room temperature for 30 min in 2% chlorhexidine. Inhibition of adherence was greatest when the organisms were grown in conditions that enhanced adherence the most, i.e., growth to stationary phase in high concentrations of galactose and sucrose. Yeasts grown in high concentrations of galactose, which were the most adherent to acrylic, were also the most sensitive to the fungicidal action of chlorhexidine gluconate, whereas those grown in a low concentration of glucose were the least adherent and also the most resistant. Adherence to acrylic of seven strains of C. albicans isolated from active infections (I strains) and grown in medium containing 500 mM sucrose was significantly higher than that of four strains obtained from asymptomatic carriers (C strains). A spectrum of adherence values was obtained when various yeasts other than C. albicans were tested.

Acrylic Resins↗
PubMed1984

The effect of cytotoxic therapy on saliva and oral flora.

Oral complications of cytotoxic therapy result from direct mucosal damage and, indirectly, occur as a consequence of immunosuppression. Such problems are further exacerbated as a result of associated xerostomia and secondary infection. Therefore, the aims of this study were to examine the salivary volume and composition (amylase, IgA, and lysozyme) together with the oral carriage of potential pathogens in patients receiving cytotoxic therapy. A pilot study comparing healthy controls with patients on chemotherapy for malignant conditions indicated that there were differences between the two groups. Therefore, a longitudinal study was initiated and twelve patients were assessed prior to and 4 and 12 weeks after the start of cytotoxic therapy. The 10-minute forced-spitting salivary volume and amylase and IgA levels all declined significantly over the 12-week period. Lysozyme content did not change. A quantitative increase in the oral carriage of Candida species, coliforms, and Staphylococcus aureus was also observed during therapy. Hence, it is concluded that cytotoxic chemotherapy results in a decreased salivary flow, a reduction in salivary amylase and IgA, and an increase in the oral carriage of opportunistic pathogens.

Adult↗
PubMed1984

Antibiotic sensitivity and phage typing of Staphylococcus aureus isolated from non-hospitalized patients with angular cheilitis.

Strains of Staphylococcus aureus were isolated from 360 patients with angular cheilitis. Of these 24 per cent were sensitive to penicillin G, 74 per cent to tetracycline, 93 per cent to fusidic acid and 96 per cent to erythromycin. Twenty per cent belonged to bacteriophage Group I, 9 per cent to Group II, 13 per cent to Group III, 39 percent miscellaneous and 19 per cent were untypable. A number of phage typing patterns which have been reported for strains associated with specific forms of staphylococcal disease were present in the 360 isolates. In investigations involving cross infection of Staph. aureus, both patients and staff should be examined for evidence of infection at the angles of the mouth.

Anti-Bacterial Agents↗
PubMed1984

The proteolytic potential of Candida albicans in human saliva supplemented with glucose.

The production of proteases by Candida albicans in batch cultures of human saliva supplemented with glucose was investigated with two clinical strains of Candida and both individual and pooled samples of whole saliva from volunteers. Salivary proteolysis during a 48-h period was estimated by biochemical and isoelectric focusing techniques. Candidal growth in saliva was associated with acid production and salivary proteolysis and there was a highly significant positive correlation between these two activities. Neither candidal growth nor proteolysis was observed in glucose-free control samples and with one strain of Candida cultured in the saliva of one individual. Isotachophoretic analysis of culture liquor showed a significant increase in acetate and pyruvate ions. The oral cavity provides niches that have a low pH and are periodically supplemented with dietary carbohydrates. The acidic proteases of C. albicans may play a role in the pathogenesis of oral candidoses.

Aspartic Acid Endopeptidases↗
PubMed1984

The oral carriage of yeasts and coliforms in patients on cytotoxic therapy.

The oral carriage of yeasts and coliforms in a healthy adult population and a group of patients with malignancies, undergoing cytotoxic therapy was investigated. A quantitative increase in the intra-oral carriage of Candida species and coliforms was observed during cytotoxic therapy. The most frequent yeast and the coliform isolated were Candida albicans and Escherichia coli, respectively. Thus, the oral cavity may constitute a reservoir of potentially pathogenic flora in patients on cytotoxic therapy.

Adolescent↗
PubMed1984

Factors affecting the phospholipase activity of Candida species in vitro.

The phospholipase activity of 41 isolates of oral Candida species was determined by a plate assay. Seventy nine per cent of the C. albicans isolates were phospholipase producers whereas none of the C. tropicalis, C. glabrata or C. parapsilosis isolates produced the enzyme. The degree of phospholipase activity (Pz value) of individual isolates was remarkably constant despite the large variation in activity among different isolates. Experiments with 10 phospholipase positive C. albicans isolates indicate that phospholipase production in vitro is limited to a narrow pH range (c. 3.6-4.7) and is suppressed by increasing concentrations of sucrose and galactose in the media (r = 0.9). Hence, candidal phospholipases seem to play a complex role in the aetiopathology of human candidoses.

Candida↗
PubMed1984

The oral ecology of patients with severe Sjögren's syndrome.

An investigation of the commensal microflora, salivary flow rate, pH, and the degree of atrophy of the oral mucosa in ten patients with severe Sjögren's syndrome and ten control subjects, revealed a number of differences. The numbers of Streptococcus salivarius, Neisseria pharyngis, Veillonella species and Micrococcus mucilagenosus isolated from patients with Sjögren's syndrome were significantly reduced, while the numbers of Candida spp. and Staphylococcus aureus were significantly increased when compared with control subjects. In addition the salivary pH of the Sjögren's group was significantly reduced and the degree of mucosal atrophy increased compared with controls.

Candida↗
PubMed1983

Hepatitis B Vaccine.

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Clinical Trials as Topic↗
PubMed1983

The prevalence of enterococci in the dental plaque of chronic hospital patients.

Enterococci have caused 2 of 3 reported cases of infective endocarditis following dental treatment of patients receiving haemodialysis. Since this could indicate an increased carriage rate of enterococci in the mouths of such patients, the prevalence of enterococci in dental plaque was compared in four groups of subjects, chronic dialysis patients, chronic cardiac patients, medical staff and dental hospital out-patients. The isolation of enterococci was significantly increased in both chronic patient groups and this may be related to their greater exposure to antibiotic therapy.

Adult↗
PubMed1983

Salivary gland dysfunction following radioactive iodine therapy.

Radioactive iodine is used extensively for the treatment of thyrotoxicosis and thyroid carcinoma. Iodine is actively taken up by the salivary glands and, following its use, salivary dysfunction may result as a consequence of radiation damage. The literature is reviewed and a case is reported in which a patient presented with a significant increase in caries rate attributed to salivary dysfunction following radioactive iodine therapy for a thyroid carcinoma.

Adult↗
PubMed1983

The role of iron deficiency in experimentally-induced oral candidosis in the rat.

In comparison with normal rats, those with iron deficiency anaemia showed no significant difference in susceptibility to experimental infection with Candida albicans although anaemic rats had a significantly greater incidence of persistent infection. These findings support the suggestion that patients with chronic candidosis should be investigated for iron deficiency.

Anemia, Hypochromic↗
PubMed1983

Prophylaxis for infective endocarditis: antibiotic sensitivity of dental plaque.

The antibiotic sensitivity pattern of bacteria isolated from bacteraemia after dental extraction was compared with that of bacteria isolated from dental plaque samples from the same patient. The results supported the current practice of using penicillin and erythromycin empirically for prophylaxis. The prediction of the most appropriate antibiotic for prophylaxis using dental plaque samples was most accurate when the minimum inhibitory concentration (MIC) of plaque isolates were used. It appears that a predictive test using dental plaque may be of some value in patients with recent or long-term antibiotic therapy.

Adult↗
PubMed1983

An investigation of the factors involved in increased adherence of C. albicans to epithelial cells mediated by E. coli.

An in vitro study was carried out in order to investigate the effect of Escherichia coli on the adherence of Candida albicans to epithelial cells. Pre-incubation of HeLa cell monolayers with E. coli cell suspensions resulted in a large, significant increase in candidal adherence. Similar increases in adherence to HeLa cells were observed when incubation of C. albicans and HeLa cell monolayers was carried out in the presence of a mannose-specific lectin, concanavalin A. The enhanced adhesion of C. albicans due to both E. coli and concanavalin A was significantly reduced in the presence of mannose and alpha-methyl-D-mannoside although both sugars alone significantly increased candidal adherence. These studies indicate that the increased candidal adherence due to the presence of E. coli is mediated by the presence of fimbriae on the bacterial cells and mannose-like receptors on both the surfaces of C. albicans and the epithelial cells.

Candida albicans↗
PubMed1983

Growth and acid production of Candida albicans in carbohydrate supplemented media.

Aerobic and anaerobic growth characteristics and acid production of a clinical and a reference laboratory strain of Candida albicans in 0.1 M, glucose or sucrose-supplemented batch cultures were examined for 72 h, at 37 degrees C. Both strains gave sigmoid growth curves, aerobically, and the pH dropped from 7.0 to 3.5 in 48 h. Candidal growth or acid production was not observed in submerged, anaerobic cultures. The specific growth rate (mu) of the clinical strain of Candida was significantly greater than the reference strain, in both sugar media. The major acidic component initiating and sustaining the pH drop appeared to be acetate, although formate, pyruvate and propionate were detected in varying proportions in glucose or sucrose cultures. These anionic, acidic metabolites of C. albicans, may play a role in the pathogenesis of mucosal candidoses such as chronic atrophic candidosis.

Acetates↗
PubMed1982

Factors affecting the in-vitro adherence of the fungal oral pathogen Candida albicans to epithelial cells of human origin.

An in-vitro technique was used to investigate the effects of oral commensal bacteria, serum, saliva, germ-tube formation and pH on the adherence of two strains of C. albicans to HeLa cells. Streptococcus salivarius and Streptococcus mitior reduced candidal adhesion whereas Streptococcus mutans had no significant effect. A mixed salivary pellicle on HeLa cells significantly enhanced candidal adhesion and a serum layer had no effect. Yeasts pre-incubated in whole saliva for 3 h showed significantly greater adhesion to HeLa and human embryonic kidney epithelial cells than yeasts in phosphate-buffered saline. The adherence of hyphal phase candida was significantly greater than in the blastospore phase. Adhesion varied with the pH of the test medium, maximal adherence was at pH 3 with less under neutral pH conditions. The factors involved in the adhesion of C. albicans to epithelial surfaces are complex and may play a rôle in the aetiopathology of human mucosal candidoses.

Adhesiveness↗
PubMed1982

The effect of dietary carbohydrates on the in-vitro adhesion of Candida albicans to epithelial cells.

The effects of dietary carbohydrates on the adherence of Candida albicans to HeLa epithelial monolayers and buccal epithelial cells were compared by two assay systems. Candida preincubated in 0.5M, glucose, sucrose, galactose, xylitol or maltose medium produced a significant enhancement in adhesion to both types of epithelial cells. Maltose was the most effective sugar and glucose the least effective in promoting adhesion, while lactose had no significant effect. A clinical isolate of C. albicans demonstrated a greater overall enhancement in adhesion from preincubation with glucose, sucrose and maltose, when compared with a reference laboratory strain of Candida. These results imply that exogenous or endogenous carbon sources may affect the oral and vaginal carriage of C. albicans, by modifying their adhesive properties.

Candida albicans↗