PubMed Health⌕ Search

Biomedical subjects

L P Samaranayake

Publications and source records attributed to L P Samaranayake.

At least 235 records · Page 13Linked to original sources
PubMed1986

A comparison of the effects of chlorhexidine gluconate, amphotericin B and nystatin on the adherence of Candida species to denture acrylic.

Pretreatment of denture acrylic with nystatin, amphotericin B and chlorhexidine gluconate significantly reduced the subsequent adherence of Candida species to acrylic, although chlorhexidine and nystatin were more effective than amphotericin B. The duration of chlorhexidine-mediated inhibition of adherence (up to 19 days) was much longer than that of amphotericin B (24 h) or nystatin (48 h). Exposure of stationary-phase cells of Candida species for a short period to sublethal concentrations of chlorhexidine, or growth of Candida species with sublethal concentrations of chlorhexidine for 24 h resulted in a reduction in the ability of the yeasts to adhere to denture acrylic. The organisms grown in the presence of chlorhexidine were more susceptible to spheroplasting with Zymolyase 20T, indicating that chlorhexidine affects the cell surface composition of Candida species.

Acrylic Resins↗
PubMed1986

Effect of saliva and serum on the adherence of Candida species to chlorhexidine-treated denture acrylic.

The effect of saliva and serum on the adherence of five strains of Candida albicans and one each of C. tropicalis and C. glabrata to chlorhexidine-pretreated acrylic was measured in vitro. A four-fold dilution of saliva or serum significantly inactivated the fungicidal effect of chlorhexidine gluconate. Pretreatment of the acrylic with unstimulated mixed saliva for 30 min led to a reduced adherence for all the Candida strains tested, whilst a similar pretreatment with serum slightly increased adhesion. Moreover treatment of saliva- or serum-coated acrylic with chlorhexidine gluconate 2% reduced adherence by between 19% and 86%. The inhibition of yeast adherence by chlorhexidine persisted for up to 19 days after the exposure of the acrylic strips to the disinfectant.

Adhesiveness↗
PubMed1986

Nutritional factors and oral candidosis.

A variety of nutritional factors including deficiencies of iron, folic acid, vitamins, and diets rich in carbohydrates have been implicated in the pathogenesis of oral candidal infections. The following reviews the growing body of data, from in vivo and in vitro studies, related to each of these implicated factors. Although much disagreement exists as to the specific roles played by these individual factors, there is little doubt that nutritional factors either acting locally or via systemic mechanisms could significantly affect the pathogenesis of oral candidoses. Hence, the role of these less well-characterised predisposing factors should be considered when one is treating patients with intractable oral candidal infections.

Animals↗
PubMed1986

Growth and acid production of Candida species in human saliva supplemented with glucose.

Growth characteristic and acid production of oral isolates of Candida albicans and Candida glabrata in glucose supplemented and glucose-free, pooled, human whole saliva were examined. Both Candida species exhibited sigmoidal growth curves in batch cultures of mixed saliva, supplemented with glucose. The growth of Candida in saliva was accompanied by a rapid decline in pH from 7.5 to 3.2 over 48 h and the major acidic components initiating and sustaining this pH drop were pyruvates and acetates. These acidic metabolites may play an important role in the pathogenesis of oral Candida infections.

Candida↗
PubMed1986

A comparison of oral rinse and imprint sampling techniques for the detection of yeast, coliform and Staphylococcus aureus carriage in the oral cavity.

The sensitivity of the impression culture, the neat rinse culture (NRC) and the concentrated rinse culture (CRC) methods in detecting the oral carriage of yeasts, coliforms and Staphylococcus aureus was estimated in 75 individuals. The recovery of organisms from the imprint cultures of the tongue and the CRC was similar and there was highly significant positive correlation between the two techniques. The CRC was simple to perform, equally sensitive and superior in quantifying yeast, coliform and S. aureus carriage than the imprint culture technique. Hence, it is suggested that the CRC technique be preferentially employed in future investigations to obtain comparable data from different centres.

Adult↗
PubMed1986

Biotypes of oral Candida albicans and Candida tropicalis isolates.

213 oral isolates of Candida albicans and 62 isolates of C. tropicalis were tested for their hydrolytic enzyme profiles with the API ZYM system. One major biotype accounted for more than 50% of the isolates and a number of minor biotypes was recognized in both Candida species. The enzyme profiles of the major biotypes were identical and one quarter of the C. tropicalis isolates possessed a beta-glucosidase which has not been previously described.

Candida↗
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↗