Increase of ribavirin dose improves sustained virological response in HCV-genotype 1 patients with a partial response to peg-interferon and ribavirin

Background and aim. In patients with chronic hepatitis C receiving Peg interferon/ribavirin (PEG-IFN/RBV) who do not achieve ≥ 2log-reduction in HCV-RNA at week 12 (null responders, NR) and in those with ≥ 2log-decrease but detectable at week 24 (partial responders, PR) the probability to achieve the sustained virological response (SVR) is almost null. The aim of this study was to investigate the efficacy of individualized schedule of progressively increased RBV doses in the setting of PEG-IFN/RBV treatment. Material and methods. PR or NR to PEG-IFN/RBV instead of discontinuing treatment were enrolled to receive increasing doses of RBV until a target theoretical concentration ([tRBV]) of ≥ 15 μmol/L (by pharmacokinetic formula based on glomerular filtration rate). HCV-RNA was assessed every 4 weeks and, if detectable, RBV dose was gradually increased until negativization. Twelve weeks later, patients with detectable HCV-RNA discontinued therapy while those with undetectable HCV-RNA continued for further 48 weeks. Results. Twenty genotype-1 patients (8 NR and 12 PR) were enrolled. After 12 weeks 9 (45%) were still HCV-RNA positive and were discontinued, while remaining 11 had undetectable HCV-RNA. One stopped treatment for side effects. Ten completed treatment. Five (all PR) achieved SVR. Side effects incidence was similar to that observed during PEG-IFN/RBV. Conclusions. In conclusion, RBV high doses, according to individualized schedule, increase SVR in PR on a similar extent to that of triple therapy but without increase of side effects. Such treatment should be considered in PR with no access or intolerant to protease inhibitors (PI)

Flow cytometry analysis of an in situ PCR for the detection of human immunodeficiency virus type-1 (HIV-1) proviral DNA

The polymerase chain reaction (PCR) (1,2) is extremely sensitive and flexible, and in theory, will detect a single copy of a specific DNA (or retrotranscribed RNA) sequence either in cell cultures or in clinical samples (3). PCR technology has, therefore, been applied to the diagnosis of a wide range of clinical conditions, in particular, infectious disease

Sodium hypochlorite-, chlorine dioxide-, and peracetic acid-induced genotoxicity detected by the Comet assay and Saccharomyces cerevisiae D7 tests

Mutagenicity of drinking water is due not only to industrial, agricultural and urban pollution but also to chlorine disinfection by-products. Furthermore, residual disinfection is used to provide a partial safeguard against low level contamination and bacterial re-growth within the distribution system. The aims of this study were to further evaluate the genotoxic potential of the world wide used disinfectants sodium hypochlorite and chlorine dioxide in human leukocytes by the Comet assay and in Saccharomyces cerevisiae strain D7 (mitotic gene conversion, point mutation and mitochondrial DNA mutability, with and without endogenous metabolic activation) and to compare their effects with those of peracetic acid, proposed as an alternative disinfectant. All three disinfectants are weakly genotoxic in human leukocytes (lowest effective dose 0.2 p.p.m. for chlorine dioxide, 0.5 p.p.m. for sodium hypochlorite and peracetic acid). The results in S.cerevisiae show a genotoxic response on the end-points considered with an effect only at doses higher (5- to 10-fold) than the concentration normally used for water disinfection; sodium hypochlorite and peracetic acid are able to induce genotoxic effects without endogenous metabolic activation (in stationary phase cells) whereas chlorine dioxide is effective in growing cells. The Comet assay was more sensitive than the yeast tests, with effective doses in the range normally used for water disinfection processes. The biological effectiveness of the three disinfectants on S.cerevisiae proved to be strictly dependent on cell-specific physiological/biochemical conditions. All the compounds appear to act on the DNA and peracetic acid shows effectiveness similar to sodium hypochlorite and chlorine dioxide

A battery of in vivo and in vitro tests useful for genotoxic pollutant detection in surface waters

Abstract Since the 1980s, stricter water quality regulations have been promulgated in many countries throughout the world. We discuss the application of a battery of both in vivo and in vitro genotoxicity tests on lake water as a tool for a more complete assessment of surface water quality. The lake water concentrated by adsorption on C18 silica cartridges were used for the following in vitro biological assays: gene conversion, point mutation, mitochondrial DNA mutability assays on the diploid Saccharomyces cerevisiae D7 strain, with or without endogenous P450 complex induction; DNA damage on fresh human leukocytes by the comet. Toxicity testing on yeast and human cells was also performed. In vivo genotoxicity was determined by the comet assay on two well-established bio-indicator organisms of water quality (Cyprinus carpio erythrocytes and Dreissena polymorpha haemocytes) exposed in situ. The in vivo experiments and the water samplings were carried out during different campaigns to detect seasonal variations of both the water contents and physiological state of the animals. Temperature and oxygen level seasonal variations and different pollutant contents in the lake water appeared to affect the DNA migration in carp and zebra mussel cells. Seasonal variability of lake water quality was also evident in the in vitro genotoxicity and cytotoxicity tests, with regards to water pollutant quantity and quality (directacting compounds or indirect-acting compounds on yeast cells). However, the measured biological effects did not appear clearly related to the physical-chemical characteristics of lake waters. Therefore, together with the conventional chemical analysis, mutagenicity/genotoxicity assays should be included as additional parameters in water quality monitoring programs: their use could permit the quantification of mutagenic hazard in surface waters