Growth of Candida albicans in human saliva is supported by low-molecular-mass compounds.

Saliva plays a key role in the maintenance of a stable oral microflora. It contains antimicrobial compounds but also functions as a substrate for growth of bacteria under conditions of low external nutrient supply. Besides bacteria, yeasts, in particular Candida albicans, commonly inhabit the oral cavity.

Sphingoid bases inhibit acid-induced demineralization of hydroxyapatite.

Calcium hydroxyapatite (HAp), the main constituent of dental enamel, is inherently susceptible to the etching and dissolving action of acids, resulting in tooth decay such as dental caries and dental erosion. Since the prevalence of erosive wear is gradually increasing, there is urgent need for agents that protect the enamel against erosive attacks. In the present study we studied in vitro the anti-erosive effects of a number of sphingolipids and sphingoid bases, which form the backbone of sphingolipids.

Phytosphingosine kills Candida albicans by disrupting its cell membrane.

The mechanism of action of phytosphingosine (PHS), a member of the sphingosine family which has candidacidal activity when added externally, was investigated. Previously, it has been reported that the fungicidal activity of PHS is based on the induction of caspase-independent apoptosis. In contrast, we found that addition of PHS causes a direct permeabilization of the plasma membrane of yeast, highlighted by the influx of the membrane probe propidium iodide, and the efflux of small molecules (i.

Energy depletion protects Candida albicans against antimicrobial peptides by rigidifying its cell membrane.

Inhibitors of the energy metabolism, such as sodium azide and valinomycin, render yeast cells completely resistant against the killing action of a number of cationic antimicrobial peptides, including the salivary antimicrobial peptide Histatin 5. In this study the Histatin 5-mediated killing of the opportunistic yeast Candida albicans was used as a model system to comprehensively investigate the molecular basis underlying this phenomenon. Using confocal and electron microscopy it was demonstrated that the energy poison azide reversibly blocked the entry of Histatin 5 at the level of the yeast cell wall.

Acute effects of hemodialysis on salivary flow rate and composition.

Aims: To evaluate acute effects of hemodialysis (HD) on the salivary flow rate, pH and biochemical composition before, during and after completion of a dialysis session.

Material And Methods: Unstimulated whole saliva (UWS) and chewing-stimulated whole saliva (CH-SWS) were collected in 94 HD patients. Salivary flow rate, pH, concentrations of total protein, albumin, cystatin C, secretory immunoglobulin A (S-IgA) and of sodium, potassium and urea were measured.

Oral and salivary changes in patients with end stage renal disease (ESRD): a two year follow-up study.

Objectives: To compare oral health, salivary flow rate, xerostomia and thirst in end stage renal disease (ESRD) patients remaining on dialysis treatment and after renal transplantation.

Design: Longitudinal observation.

Setting: ESRD patients recruited from dialysis centres in Amsterdam, The Hague and Utrecht, The Netherlands.

The human cathelicidin peptide LL-37 and truncated variants induce segregation of lipids and proteins in the plasma membrane of Candida albicans.

The human cathelicidin peptide LL-37 and several truncated variants differ in their capability to transmigrate over the plasma membrane of Candida albicans. We investigated whether retention at the cell perimeter or membrane transmigration affects their membrane-disrupting activities and candidacidal properties. Using fluorescein-labeled peptides, we demonstrate that LL-37 and its C-terminally truncated peptide LL-31 remain permanently associated with the perimeter of the cell.

The management of xerostomia in patients on haemodialysis: comparison of artificial saliva and chewing gum.

Many patients on haemodialysis (HD) therapy suffer from a dry mouth and xerostomia. This can be relieved by mechanical and gustatory stimulation or palliative care. The aim of this crossover study was to investigate the effect and preferences of a sugar-free chewing gum (Freedent White) and a xanthan gum-based artificial saliva (Xialine) in the management of xerostomia in chronic HD patients.

Chewing gum and a saliva substitute alleviate thirst and xerostomia in patients on haemodialysis.

Background: Most patients on haemodialysis (HD) have to maintain a fluid-restricted diet to prevent a high interdialytic weight gain (IWG). The prevalence of xerostomia (the feeling of a dry mouth) is higher in HD patients than in controls. Recently, we demonstrated that xerostomia and thirst were positively correlated with IWG in HD patients.

Interdialytic weight gain in patients on hemodialysis is associated with dry mouth and thirst.

Background: Patients receiving hemodialysis (HD) have to maintain a fluid-restricted diet. Severe thirst can induce noncompliance to this diet, resulting in an increase of interdialytic weight gain (IWG = weight predialysis - postdialysis) associated with poor patient outcomes. Because oral dryness may contribute to experienced thirst, we investigated the possible relation between thirst, salivary flow rate, xerostomia, and IWG.

Isolation of different high-Mr mucin species from human whole saliva.

By using CsCl-density-gradient ultracentrifugation, two high-Mr mucin species were isolated from human whole saliva, having buoyant densities in 0.2 M-guanidinium chloride of approx. 1.

Immunochemical analysis of high molecular-weight human salivary mucins (MG1) using monoclonal antibodies.

Using four Mabs with different specificities for salivary mucins, an ELISA has been developed in which human whole saliva, glandular salivas, salivary protein fractions and purified, high molecular-weight, mucin fractions (MG1) isolated from human submandibular and sublingual glandular tissues have been immunochemically analysed. All four Mabs reacted with MG1s. Three of them reacted with the purified, low molecular-weight salivary mucins (MG2).

Aggregation of oral bacteria by human salivary mucins in comparison to salivary and gastric mucins of animal origin.

Seventeen strains of oral bacteria of the genera Actinomyces (5), Bacteroides (3), and Streptococcus (9) were tested for aggregation by the human whole salivary mucin fraction (HWSM) in comparison to three types of animal mucin preparations from submandibular glands of cow (BSM) and sheep (OSM), and from the stomach of pig (PGM). Considerable variation was seen with respect to the rate and titer of aggregation induced by these mucins. The aggregating activity of HWSM varied widely among the different bacterial strains.

Involvement of human mucous saliva and salivary mucins in the aggregation of the oral bacteria Streptococcus sanguis, Streptococcus oralis, and Streptococcus rattus.

The contribution of human parotid (Par) and submandibular/sublingual (SM/SL) saliva and of the human whole salivary mucin fraction (HWSM) to saliva-induced bacterial aggregation was studied for S. sanguis C476, S. oralis I581, and S.

Isolation of high molecular weight mucins from human whole saliva by ultracentrifugation.

A high molecular weight mucin fraction was prepared from human whole saliva using relatively mild conditions. The method involves ultracentrifugation of human whole saliva in the presence of 7.2 M urea and 0.

Viscosity of human salivary mucins: effect of pH and ionic strength and role of sialic acid.

The viscosity of isolated human salivary mucins has been studied as a function of shear rate, mucin concentration, pH, and ionic strength. At neutral pH, viscosity increased proportionally with mucin concentrations between 0 and 14 mg/ml. Increasing the ionic strength from 35 to 235 mM resulted in an approximately 50% decrease in specific viscosity.

Aggregation of 27 oral bacteria by human whole saliva. Influence of culture medium, calcium, and bacterial cell concentration, and interference by autoaggregation.

Twenty-seven oral strains of the genera Actinomyces (5), Bacteroides (3), and Streptococcus (19) were tested for aggregation by human whole saliva, as well as the effect of culture medium, Ca-ions, and bacteria concentration thereupon. Of the media tested, GF-broth gave rise to less interference by autoaggregation or higher aggregation titers than BHI and TSB, and was used throughout this study. In most cases, Ca-ions (1 mM) only enhanced the rate of induced aggregation, whereas raising the bacteria concentration increased the rate of both induced- and autoaggregation.

Comparison of different assays for the aggregation of oral bacteria by human whole saliva.

For comparison, human whole saliva-induced aggregation was studied by phase-contrast microscopy, spectrophotometry combined with macroscopic observations, and in microtiterplate assay under identical experimental conditions for Actinomyces viscosus HG 85 (T14-V) and HG 380 (T14-AV), Bacteroides gingivalis HG 66 (W 83), Streptococcus rattus HG 59 (BHT), and Streptococcus sanguis I HG 169. The entire process of formation, extension, and sedimentation of aggregates could merely be observed by the combination of these assays. The very first stages of aggregation could only be detected and quantitated by phase-contrast microscopy.