The antifungal activity and cytotoxicity of silver containing denture base material.

OBJECTIVE: Denture base materials are susceptible to fungal adhesion, which is an important etiological issue in the pathogenesis of denture stomatitis. The purpose of this in vitro study was to evaluate the antifungal activity and cytotoxicity of denture base material containing silver microparticles. MATERIALS AND METHODS: The polymethyl methacrylate (PMMA) denture base material was used, and silver microparticles were added to the polymer powder in different concentrations by volume (0%, 0.25%, 0.5%, and 1%). Their antifungal activity against Candida albicans was assessed in terms of colony-forming units. PMMA disc specimens containing silver microparticles were eluted with culture medium for 1, 2, and 5 days. The cytotoxicity of the eluates to cultured L929 mouse fibroblast cells was evaluated using a real-time cell analysis (RTCA) system and the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay. RESULTS: The antifungal effect against C. albicans increased with the percentage of silver microparticles (P < 0.05). For both tests, both RTCA and the MTT assay, no time- or silver-dependent cytotoxicity of PMMA denture base material containing silver microparticles was observed. CONCLUSIONS: PMMA denture base material containing silver microparticles have antifungal activity and no cytotoxic effect.

Can Helicobacter pylori be eradicated with high-dose proton pump inhibitor in extensive metabolizers with the CYP2C19 genotypic polymorphism?

Proton pump inhibitors (PPI) metabolism and pharmacokinetics are regulated by cytochrome P450 enzymes in the liver. Cytochrome P450 2C19 (CYP2C19) polymorphism plays an import role in the metabolism of PPIs. The three possible genotypes for CYP2C19 each has a distinct effect on the pharmacodynamics of PPIs. Homozygote extensive metabolizers (HomEM) are the most frequent genotype and have two wild-types (non-mutant) (*1/*1) alleles. HomEM is associated with increased enzyme activity, which increases the rate of PPI metabolism. Intragastric pH, which is required for eradication, is lowest in HomEM. In HomEMs, an insufficient increase in intragastric pH results in decreased anti-Helicobacter pylori (HP) efficacy of the antibiotics and, therefore, lower eradication rates. We determined whether the HP eradication rate would increase after high-dose PPI treatment of extensive PPI metabolizers who had been treated unsuccessfully with a standard PPI dose. In our report, increasing the PPI dosage in patients with genotype polymorphisms may be effective on eradication rates. Eradication rates are directly affected by CYP2C19 polymorphisms, and eradication treatments should be planned considering such genotypic polymorphisms. Hence, CYP2C19 genotyping prior to treatment may facilitate determination of the optimum PPI dose to improve the therapeutic outcome. However, further researches are required to confirm this hypothesis.

Effect of cytochrome P450 2C19 polymorphisms on the Helicobacter pylori eradication rate following two-week triple therapy with pantoprazole or rabeprazole.

OBJECTIVE: Cytochrome P450 2C19 (CYP2C19) polymorphisms play an important role in the metabolism of proton pump inhibitors. Rabeprazole is primarily metabolized via non-enzymatic pathways. In this study, we determined whether rabeprazole- and pantoprazole-based eradication treatments were influenced by CYP2C19 polymorphisms. PATIENTS AND METHODS: A total of 200 patients infected with Helicobacter pylori were treated with either 40 mg of pantoprazole or 20 mg of rabeprazole plus 500 mg of clarithromycin, 1000 mg of amoxicillin twice daily for 2 weeks. CYP2C19 genotype status was determined by Polymerase Chain Reaction (PCR)-restriction-fragment-length polymorphism. The genotypes of cytochrome P450 2C19 were classified as homozigote extensive metabolizer (HomEM), heterozigote metabolizer (HetEM) and poor metabolizer (PM). The CYP2C19 genotype of all patients, the effectiveness of the treatment, the effect of the genotypic polymorphism on the treatment were assessed. RESULTS: The frequencies of HotEM, HetEM, PM were 78%, 19.5% and 2.5%, respectively. 48% (n = 96) of the patients received treatment with rabeprazole and 52% (n = 104) with pantoprazole. The eradication rate was 64.7% for HomEM, 79.4% for HetEM, 100% for PM (p = 0.06). In HetEM, PM, are considered as a single group, the eradication rates were higher in patients with the HetEM and PM (HetEM+PM) genotypes than in those with the wild-type genotype (81.8 vs. 64.7% p = 0.031). Among the patients treated with rabeprazole, the eradication rates were significantly lower in those with the HomEM genotype than in those with the HetEM+PM genotypes (60% vs. 85.7% p = 0.023). CONCLUSIONS: The genotypic polymorphism is effective on the rate of eradication. Eradication treatment rate with rabeprazole is influenced by CYP2C19 genotype.