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Lansoprazole is a gastric parietal cell proton pump inhibitor that is also active against Helicobacter pylori in vitro. We aimed to investigate further the mechanism of its antimicrobial effect. The antimicrobial activity of lansoprazole and of its sulfenamide, a rearrangement product occurring spontaneously in acid environments, was studied by determining the MICs and MBCs for 11 cytotoxic and eight non-cytotoxic H. pylori strains and by measuring the rapidity of bacterial killing. The MIC90 and MBC90 were 2.5 mg/L and 10 mg/L, respectively, both for lansoprazole and for its sulfenamide. Cytotoxic strains were as susceptible as non-cytotoxic strains. The sulfenamide exhibited faster bactericidal activity. Lansoprazole did not inhibit the toxin-induced vacuolization of HeLa cells by a cytotoxic strain, hence its anti-H. pylori activity does not depend on inhibition of a v-ATPase-mediated, toxin-induced activity. Sulfenamide formation is likely to occur in vivo in the gastric environment, thus enhancing the bactericidal activity of the drug. Lansoprazole is likely to be useful, in association with antibiotics, in the treatment of H. pylori infection regardless of the cytotoxicity of the infecting strain. [ABSTRACT FROM AUTHOR]

The sperm plasma membrane is a sensitive target to oxidative stress. The most representative reactive oxygen species (ROS) scavengers in the genital tract, hypotaurine and glutathione, require, for their synthesis, cysteine whose availability is associated with the 1-carbon cycle (1-CC). Human, bovine and ascidian spermatozoa were incubated with compounds supporting the 1-CC (Vitamin B6, Methylcobalamin, 5 Methyl Tetrahydrofolate, Zinc Bisglycinate and N-acetyl-cysteine) (TRT) and compared to the effects induced solely by N-acetyl-cysteine (NAC). In control groups (CNTRL), spermatozoa were incubated with medium alone. After 90 and 180 minutes of incubation, the mitochondrial membrane potential (ΔΨM) in TRT and NAC was significantly (P < 0.01) higher than in CNTRL. At H2DCFDA evaluation, ROS production differed between species whereas, at 2-OH Ethidium, it significantly decreased in bovine TRT group. Intracellular pH (pHi) did not significantly vary in relation to treatment. In ascidian spermatozoa, the NAC supplementation decreased external pH, which in turn brought to a pHi lowering. Buffering seawater with NaHCO3 reversed the beneficial effects of N-acetyl-cysteine supplementation. In conclusion, both fully supporting the 1-CC and treatment with N-acetyl-cysteine alone improved kinetics, ΔΨM and ROS production in mammalian sperm demonstrating for the first time the direct in vitro effects of these compounds on sperm functionality. [ABSTRACT FROM AUTHOR]