The protective activity of alpha-hederine against H2O2 genotoxicity in HepG2 cells by alkaline comet assay.

This study was designed to evaluate the protective effect of alpha-hederine (alpha-hed) against H2O2-mediated DNA damage on HepG2 cell line by the alkaline comet assay. For the protective effect of alpha-hed study, cells were treated according to three protocols: pre-treatment, simultaneous treatment and post-treatment. The effect of alpha-hed on catalase activity was evaluated after treating the cells with 3.36 mg/ml of 3-amino-1,2,4-triazole (AMT) singly or in combination with alpha-hed (1.5 or 3 microg/ml) and H2O2 (8.8 microM) during 1 h. The catalase activity was also biochemically measured after treating cells with alpha-hed at 1.5, 3, or 15 microg/ml during 1 h. Additionally, the influence of alpha-hed on membrane RedOx potential, pool of reduced glutathione and total protein content was evaluated by flow cytometry. In the pre-treatment, the two concentrations of alpha-hed (1.5 and 3 microg/ml) decreased the lesions induced by H2O2 (8.8 microM) significantly. This decrease was about 57.2% and 66.1%, respectively. Similar results were observed when cells were treated with alpha-hed and H2O2 simultaneously. The decrease of H2O2-induced lesions was about 78.2% and 83.2% (alpha-hed 1.5 and 3 microg/ml, respectively). In the post-treatment protocol, this decrease was not significant. The combination of AMT and H2O2 induced more DNA damage than H2O2 alone (tail moment (TM) means was 31.4% and 21.8%, respectively). When alpha-hed was added to this mixture, TM means were reduced significantly (17.4% for alpha-hed 1. 5 microg/ml and 15.5% for alpha-hed 3 microg/ml). Up to 6.9 microg/ml, alpha-hed enhanced catalase activity (60.5%), followed by a decrease of the activity. Total protein content and membrane RedOx potential were slightly increased up to 11 microg/ml (14% and 3.6%, respectively) followed by a drop and a plateau. Pool of reduced glutathione remained unchanged up to 10 microg/ml then dropped and reached a plateau. In conclusion, alpha-hed could exert its protective effect against H2O2-mediated DNA damage by scavenging free radicals or by enhancing the catalase activity.

Formation of nitrogen-containing metabolites from the main iridoids of Harpagophytum procumbens and H. zeyheri by human intestinal bacteria.

The study of the metabolism of iridoid glycosides from Harpagophytum procumbens and Harpagophytum zeyheri by human intestinal bacteria, was realized in order to elucidate compounds responsible for the pharmacological activities of Harpagophytum. Harpagide, harpagoside and 8-O-p-coumaroyl-harpagide were transformed into the pyridine monoterpene alkaloid aucubinine B by human fecal flora and by bacteria isolated from this flora. Aucubinine B was also prepared from harpagide, harpagoside and 8-O-p-coumaroylharpagide, by beta-glucosidase in the presence of NH4+.

Evaluation of a flow cytofluorometric method for rapid determination of amphotericin B susceptibility of yeast isolates.

A rapid-flow cytofluorometric susceptibility test for in vitro amphotericin B testing of yeasts was evaluated and compared to the National Committee for Clinical Laboratory Standards (NCCLS) M27-T reference broth macrodilution method. The flow cytofluorometric method is based on the detection of decreased green fluorescence intensity of cells stained with DiOC5(3), a membrane potential-sensitive cationic dye, after drug treatment. Testing was performed on 134 clinical isolates (Candida spp. and Torulopsis glabrata). From the dose-response curve obtained for each isolate, three endpoints were calculated by computer analysis (the concentrations at which the fluorescence intensity was reduced by 50, 80, and 90%, i.e., 50% inhibitory concentration [IC50], IC80, and IC90, respectively). A regression analysis correlating these endpoints with the M27-T MICs showed that the best agreement was obtained with IC80. The flow cytofluorometric method showed good reproducibility with control strains. These initial results suggest that the flow cytofluorometric method is a valid alternative to the NCCLS reference method.

[A new mode of expression for the assessment of capacities of DNA repair by flow cytometry]. / Nouveau mode d'expression pour l'évaluation des capacités de réparation de l'ADN par cytométrie en flux.

Flow cytometry technic was used to study DNA synthesis of Hep G2 cells following mitomycin C and adriblastine treatments during 24 hours. DNA synthesis was expressed by 2 methods: the new expression global DNA synthesis (S+G2)/G1 that considered the cells during scheduled and unscheduled DNA syntheses of S and G2 phases and the cell cycle (Fox program) that evaluated the cells during scheduled DNA synthesis by the terms G1 = 2n, S = 2n+x and G2 = 4n which excluded unscheduled DNA synthesis. The experimental data treated with this new expression led to the determination of threshold concentrations for the two tested compounds where the DNA repair mechanisms were overloaded, leading to cell death. This term was shown to be more accurate to describe the genotoxic action of compounds. Furthermore, these threshold concentrations of DNA damages was found to be linked with significant increase of micronuclei in the micronucleus test.

[Multicenter study of the antimicrobial activity of antiseptics on the hands. Protocols and results]. / Etude multicentrique de l'activité antimicrobienne des antiseptiques sur les mains. Protocoles et résultats.

Quantitative evaluation of in vivo activity of antiseptics in surgical-type handwashing is achieved by comparing bacterial counts on one hand after disinfection and on the other untreated hand. Handwashing, bacterial recovery and bacterial counts must be performed according to strictly standardized methods. A large number of participants is required.

[Multicenter study in actual situations of the activity of an antiseptic in the surgical washing of hands]. / Etude multicentrique en situation réelle de l'activité d'un antiseptique dans le lavage chirurgical des mains.

Results of a collaborative study carried out in three different hospitals by nine surgeons are reported. Activity of a new scrub applied according to a standardized protocol was compared with that of the different scrubs and/or antiseptics customarily used by participating surgeons with their habitual method. Activity of products was evaluated by bacterial counts in gloves. Statistical analysis of results demonstrates the value of this trial design which compares scrubs under real conditions of use.

[Inactivation of disinfectants by proteins and calcium ions as a function of their chemical constitution and bacterial species]. / Inactivation par les protéines et les ions calcium des désinfectants en fonction de leur nature chimique et des espèces bactériennes.

Activity of nine disinfectants was evaluated with interfering substances (albumin-yeast mixture and hard water), by two methods (NFT. 72 170, NFT. 72 171 and without interfering substance NFT. 72 150, NFT 72 151 respectively). Interference indexes were defined as the ratio of bactericidal concentration without interfering substances to bactericidal concentration with interfering substances. Five different ratings of interference effects were arbitrarily defined (no effect, moderate, average, strong, very strong). Proteins and hard water significantly inactivate aldehydes and quaternary ammonium salts : interference index is usually 25 but may reach 100-500. Inactivation of phenolic products by these two interfering substances is either lacking or inconsiderable. Conversely to Gram negative bacteria, activity of disinfectants on Gram positive bacteria is not significantly affected by proteins or hard water. P. aeruginosa can survive despite high concentrations of disinfectant in the presence of proteins and calcium ions. This finding may be a reason why this microorganism is difficult to eliminate from hospital wards.