Article

Amoebiasis: New Understanding and New Goals.

Research and Advanced Studies (Cinvestav), Mexico City, 07360 Mexico.
Parasitology Today (Impact Factor: 5.51). 02/1998; 14(1):1-3. DOI: 10.1016/S0169-4758(97)01176-9
Source: PubMed

ABSTRACT Mexico City, Mexico January 1997.

0 Bookmarks
 · 
59 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: 5-Nitroimidazoles are a group of antiprotozoal and antibacterial agents. Thanks to their antimicrobial activity, these chemotherapeutic agents inhibit the growth of both anaerobic bacteria and certain anaerobic protozoa. One of the useful drugs used in the treatment of infections caused by Trichomonas vaginalis, Entamoeba histolytica, and Giardia lamblia is metronidazole (MTZ). The mutagenicity of metronidazole [1-(hydroxyethyl)-2-methyl-5-nitroimidazole] has been previously shown in different prokaryotic systems but not in eukaryotic systems. The objective of this study is to determine the mutagenic and cytotoxic effects of MTZ at plasma concentration and higher in vitro. In this study, we evaluated the mutagenicity and cytotoxicity of MTZ in cultured human peripheral blood lymphocytes. Doses were selected according to plasma concentration of drug. End points analyzed included mitotic index (MI), replication index (RI), and sister chromatid exchange (SCE). An analysis of variance test (ANOVA) was performed to evaluate the results. A significant decrease (p < 0.001) in MI and RI as well as an increase in SCE frequency (p < 0.001) was observed compared with control cultures. Our results indicate the genotoxic and cytotoxic effect of MTZ in cultured human peripheral blood lymphocytes at plasma concentrations slightly higher than encountered therapeutically.
    Drug and Chemical Toxicology 01/2006; 29(1):85-94. · 1.29 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Actin cytoskeleton disruption in host cells has been demonstrated for PTPases from pathogenic microorganisms. In this work, we analysed whether the secreted acid phosphatase from Entamoeba histolytica has phosphotyrosine phosphatase activity and the possibility that this activity may participate in damaging host cells. The secreted acid phosphatase of E. histolytica, which catalyses p-nitrophenyl phosphate hydrolysis at acid pH values, was found to have phosphotyrosine phosphatase activity. The enzymatic properties of phosphotyrosine phosphatase and acid phosphatase were virtually identical and included: Km values of 10 x 10(-4) M, no requirement for divalent cations, and sensitivity to molybdate, vanadate, and tungstate. The phosphotyrosyl phosphatase activity caused significant levels of cell rounding and detachment correlating with disruption of the actin stress fibres in HeLa cells. Thus, our data suggest that secreted phosphotyrosine phosphatase could play a cytotoxic role during amoebic infection.
    International Journal for Parasitology 08/2003; 33(7):663-70. · 3.64 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Amebiasis is the infection of the human gastrointestinal tract by Entamoeba histolytica, a protozoan parasite that is capable of invading the intestinal mucosa and may spread to other organs, mainly the liver. The detection of Entamoeba histolytica from the nonpathogenic but identically appearing parasites Entamoeba dispar and Entamoeba moshkovskii is an important goal of the clinical microbiology laboratory. Currently, there is no low-cost laboratory test available for the differentiation of E. histolytica from E. dispar infections. It is likely that at least 90% of the infections previously ascribed to E. histolytica are actually E. dispar, while only the remaining 10% are infected with E. histolytica in its new sense. The present manuscript review recent advances in this regard. The purpose of this study is to alert physicians (and perhaps with their help, laboratories) to the importance of distinguishing between the two species of amoebae.