Branched amphotericin functional poly(N-isopropyl acrylamide): an antifungal polymer.

Branched poly(N-isopropylacrylamide) was functionalized with Amphotericin B (AmB) at the chain ends to produce an antifungal material. The polymer showed antifungal properties against AmB-sensitive strains of Candida albicans, Fusarium keratoplasticum and Aspergillus flavus (minimal inhibitory concentration ranged from 5 to 500 µg ml-1) but was not effective against an AmB resistant strain of C. albicans nor against Candida tropicalis. The polymer end groups bound to the AmB target, ergosterol, and the fluorescence spectrum of a dye used as a solvatochromic probe, Nile red, was blue shifted indicating that segments of the polymer became desolvated on binding. The polymer was less toxic to corneal and renal epithelial cells and explanted corneal tissue than the free drug. Also, the polymer did not induce reactive oxygen species release from peripheral blood mononuclear cells, nor did it cause a substantial release of the proinflammatory cytokines, tumour necrosis factor-α and interleukin-1ß (at 0.5 mg ml-1).

Non-conventional therapeutics for oral infections.

As our knowledge of host-microbial interactions within the oral cavity increases, future treatments are likely to be more targeted. For example, efforts to target a single species or key virulence factors that they produce, while maintaining the natural balance of the resident oral microbiota that acts to modulate the host immune response would be an advantage. Targeted approaches may be directed at the black-pigmented anaerobes, Porphyromonas gingivalis and Prevotella intermedia, associated with periodontitis. Such pigments provide an opportunity for targeted phototherapy with high-intensity monochromatic light. Functional inhibition approaches, including the use of enzyme inhibitors, are also being explored to control periodontitis. More general disruption of dental plaque through the use of enzymes and detergents, alone and in combination, shows much promise. The use of probiotics and prebiotics to improve gastrointestinal health has now led to an interest in using these approaches to control oral disease. More recently the potential of antimicrobial peptides and nanotechnology, through the application of nanoparticles with biocidal, anti-adhesive and delivery capabilities, has been explored. The aim of this review is to consider the current status as regards non-conventional treatment approaches for oral infections with particular emphasis on the plaque-related diseases.

A serine-rich glycoprotein of Streptococcus sanguis mediates adhesion to platelets via GPIb.

Streptococcus sanguis is the most common oral bacterium causing infective endocarditis and its ability to adhere to platelets, leading to their activation and aggregation, is thought to be an important virulent factor. Previous work has shown that S. sanguis can bind directly to platelet glycoprotein (GP) Ib but the nature of the adhesin was unknown. Here, we have shown that a high molecular weight glycoprotein of S. sanguis mediates adhesion to glycocalacin. The bacterial glycoprotein was purified from cell extracts by chromatography on GPIb- and wheatgerm agglutinin affinity matrices and its interaction with GPIb was shown to be sialic acid-dependent. We designated the glycoprotein serine-rich protein A (SrpA). An insertional inactivation mutant lacking the SrpA of S. sanguis showed significantly reduced binding to glycocalacin, reduced adherence to platelets and a prolonged lag time to platelet aggregation. In addition, under flow conditions, platelets rolled and subsequently adhered on films of wild-type S. sanguis cells at low shear (50/s) but did not bind to films of the SrpA mutant. Platelets did not bind to wild-type bacterial cells at high shear (1500/s). These findings help to understand the mechanisms by which the organism might colonize platelet-fibrin vegetations.

Interleukin 1 and receptor antagonist levels in gingival crevicular fluid in heavy smokers versus non-smokers.

BACKGROUND/AIMS: This study aimed to investigate the concentration of the cytokine interleukin (IL)-1beta and its receptor antagonist IL-1ra in gingival crevicular fluid (GCF) in patients with adult periodontitis who were heavy smokers compared with non-smokers. METHOD: GCF samples were collected from two groups of subjects: smokers and non-smokers. Thirty-nine GCF samples were harvested from 13 subjects with moderate to severe adult periodontitis who were heavy smokers. A further 30 GCF samples were harvested from 10 subjects with moderate to severe adult periodontitis who were non-smokers. Subjects were selected from both genders and none had any relevant systemic illness, were pregnant, had recent medication or had received any periodontal therapy in the preceding 3 months. One deep bleeding site, one deep non-bleeding site and one healthy site were investigated in each subject. Clinical measurements were recorded for each site, after obtaining a GCF sample using a Periopaper strip. IL-1beta and IL-1ra were quantified using new commercially available ELISA kits (Quantikine), and could be detected in all samples. RESULTS: For smokers, the mean concentrations for IL-1beta were 2714.5 (SD 4416.2) pg/ micro L for healthy sites, 37.0 (SD 57.2) pg/ micro L for non-bleeding periodontitis sites and 24.5 (SD 29.2) pg/ micro L for bleeding periodontitis sites. The concentrations of IL-1beta for non-smokers for the same category of sites were 393.8 (SD 867.1), 74.2 (SD 107.0) and 73.1 (SD 61.0) pg/ micro L, respectively. The mean concentrations of IL-1ra for smokers were 5.8 x 10(5) (SD 9.7) pg/ micro L for healthy sites, 2.2 x 10(5) (SD 0.15) pg/ micro L for deep non-bleeding sites and 0.19 x 10(5) (SD 0.07) pg/ micro L for deep bleeding sites. The concentrations for non-smokers were: 4.1 x 10(10) (SD 3.8), 18.1 x 10(5) (SD 20.4) and 3.2 x 10(5) (SD 2.3) pg/ micro L, respectively. Significance levels of P < 0.05 were found for comparisons of healthy vs. deep bleeding and deep non-bleeding sites for IL-1beta and IL-1ra in smokers, before adjustments for multiple testing. However, none of these comparisons reached statistical significance following adjustments for multiple testing. P < 0.05 for the correlation between IL-1beta and IL-1ra at healthy sites in smokers only. Differences in GCF concentrations for IL-1beta in smokers vs. non-smokers were significant for deep bleeding sites only (P < 0.05), the mean concentration of IL-1beta being lower in GCF from smokers vs. non-smokers. All differences in GCF concentrations of IL-1ra reached statistical significance for smokers vs. non-smokers. The mean concentrations of IL-1ra in GCF were lower in smokers compared with non-smokers for all categories of sites. CONCLUSIONS: A decreased concentration of IL-1beta and also IL-1ra was found in GCF from periodontitis sites compared to healthy sites in smokers and in non-smokers, although this did not reach statistical significance following adjustments for multiple testing. For comparisons between heavy smokers and non-smokers, statistically significant differences were found in the GCF concentrations of IL-1beta from deep bleeding sites only. Statistically significant differences were found in the IL-1ra concentrations for smokers vs. non-smokers for all categories of sites.