Recent biochemical approaches to post-testicular, epididymal contraception.
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Results from recent animal models with implications for putative human male contraceptives acting on the epididymis are reviewed. Inducing sterility by enhancing sperm transport through the epididymis has not been achieved. The induction of infertility in males of several species is easier to achieve by direct actions of drugs on sperm function (e.g. inhibition of sperm-specific isoenzymes of the glycolytic pathway by chloro-compounds) than by indirectly reducing amounts of epididymal secretions normally present in high concentration (e.g. alpha-glucosidase, L-carnitine). The former show promise for the clinic since human spermatozoa are susceptible to inhibition. On the other hand, the infertile male mice of the c-ros knock-out model demonstrate the influence of even a small region of the epididymis on fertility, so that targeting the as yet unknown epididymal factors presumably secreted in limiting amounts by this epididymal segment, is a new lead for a contraceptive. Targeting a specific sperm protein acquired in the testis, but depleted in the epididymis by toxicants that induce rapid infertility, may also lead to the discovery of new contraceptives, but these will require developing new means of organ-specific delivery of contraceptive drugs. (+info)
Resistance of Trichomonas vaginalis to metronidazole: report of the first three cases from Finland and optimization of in vitro susceptibility testing under various oxygen concentrations.
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Trichomonas vaginalis is a globally common sexually transmitted human parasite. Many strains of T. vaginalis from around the world have been described to be resistant to the current drug of choice, metronidazole. However, only a few cases of metronidazole resistance have been reported from Europe. The resistant strains cause prolonged infections which are difficult to treat. T. vaginalis infection also increases the risk for human immunodeficiency virus transmission. We present a practical method for determining the resistance of T. vaginalis to 5-nitroimidazoles. The suggested method was developed by determining the MICs and minimal lethal concentrations (MLCs) of metronidazole and ornidazole for T. vaginalis under various aerobic and anaerobic conditions. Using this assay we have found the first three metronidazole-resistant strains from Finland, although the origin of at least one of the strains seems to be Russia. Analysis of the patient-derived and previously characterized isolates showed that metronidazole-resistant strains were also resistant to ornidazole, and MLCs for all strains tested correlated well with the MICs. The suggested MICs of metronidazole for differentiation of sensitive and resistant isolates are >75 microg/ml in an aerobic 24-h assay and >15 microg/ml in an anaerobic 48-h assay. (+info)
Effect of ornidazole and clarithromycin resistance on eradication of Helicobacter pylori in peptic ulcer disease.
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BACKGROUND: Clarithromycin and nitroimidazoles such as metronidazole and ornidazole are among the most frequently used antibiotics for curing Helicobacter pylori infection. However, controversial data exist on whether their in vitro resistance has a negative impact on treatment outcome. METHODS: Patients with H. pylori positive active peptic ulcer disease were randomly assigned to receive lansoprazole 30 mg o.d., amoxycillin 1 g b.d. and ornidazole 500 mg b.d. (LAO) or lansoprazole 30 mg o.d., amoxycillin 1 g b.d. and clarithromycin 500 mg b.d. (LAC) for 2 weeks. Pre-treatment resistance to ornidazole and clarithromycin was assessed by Epsilometer (E-) test. Four weeks after completion of treatment, patients underwent a 13C urea breath test to assess H. pylori status. RESULTS: Data from 80 patients with active peptic ulcer disease and positive H. pylori status were analysed. The prevalence of primary drug resistance was 25% for metronidazole and 7.5% for clarithromycin. In patients treated with LAO, effective treatment was achieved in 87% of metronidazole-susceptible, but only 30% of metronidazole-resistant strains (P < 0.01). In the LAC group, therapy was successful in 81% of clarithromycin-susceptible strains, whereas treatment failed in all patients with primary clarithromycin resistance (n = 3). CONCLUSION: Resistance against nitroimidazoles significantly affects treatment outcome in H. pylori eradication therapy. (+info)
Effect of ornidazole on fertility of male rats: inhibition of a glycolysis-related motility pattern and zona binding required for fertilization in vitro.
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The effects of the male antifertility agent ornidazole on glycolysis as a prerequisite for fertilization were investigated in rats. Antifertility doses of ornidazole inhibited glycolysis within mature spermatozoa as determined from the lack of glucose utilization, reduced acidosis under anaerobic conditions and reduced glycolytic enzyme activity. As a consequence, cauda epididymidal spermatozoa from ornidazole-fed rats were unable to fertilize rat oocytes in vitro, with or without cumulus cells, which was not due to transfer of an inhibitor in epididymal fluid with the spermatozoa. Under IVF conditions, binding to the zona pellucida was reduced in spermatozoa from ornidazole-fed males and the spermatozoa did not undergo a change in swimming pattern, which was observed in controls. The block to fertilization could be explained by the disruption of glycolysis-dependent events, since reduced binding to the zona pellucida and a lack of kinematic changes were demonstrated by control spermatozoa in glucose-free media in the presence of respiratory substrates. The importance of glycolysis for binding to, and penetration of, the zona pellucida, and hyperactivation in rats is discussed in relation to the glycolytic production of ATP in the principal piece in which local deprivation of energy may explain the reduced force of spermatozoa from ornidazole-fed males. (+info)
The effect of gamma-radiation on nitroimidazole derivatives.
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The effect of gamma irradiation, in doses from 10 to 50 kGy on physical and chemical properties of metronidazole, ornidazole and tynidazole in solid state has been studied. Results of the measurements by the UV, IR, TLC, EPR, DSC methods revealed the presence of free radicals, products of decomposition, an increase in the melting point and a decrease or increase in the content of the substance studied. Microbiological assays proved that sterilization of the compounds studied was effective even with the smallest irradiation dose applied. The maximum tolerated dose and the safe sterilisation dose were determined. (+info)
DJ-1, a target protein for an endocrine disrupter, participates in the fertilization in mice.
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DJ-1 was first identified as an activated ras-dependent oncogene product and was later also found to be an infertility-related protein affected by sperm toxicants such as ornidazole (OR) and epichlorohydrin. These findings suggest that DJ-1 has functions in both somatic cells and sperm. In this study, to determine the relationship between DJ-1 and an endocrine disrupter and to determine the functions of DJ-1 in sperm, in vitro fertilization experiments were carried out using eggs and sperm extracted from mice that had or had not been treated with OR. We found that the amount of DJ-1 in sperm and the efficiency of fertilization decreased with the increasing dose of OR to which the mice were exposed. The addition of an anti-mouse DJ-1 serum to sperm solution before the in vitro fertilization reaction with eggs resulted in a decrease in the efficiency of fertilization to about one-third of that when pre-immune serum was added to sperm solution, indicating that DJ-1 participates in the fertilization. (+info)
Naegleria meningitis: a rare survival.
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Acute amebic meningoencephalitis caused by free-living amebae naegleria fowleri is extremely rare and uniformly fatal with only seven survivals reported till date. An interesting case of naegleria meningitis diagnosed by wet mount cytology of cerebrospinal fluid (CSF) and treated with amphoterecin B, rifampicin and ornidazole with complete recovery is presented. In cases of suspected pyogenic meningitis, if CSF staining, antigen detection or culture is negative for bacteria, a wet mount cytology of CSF for naegleria is suggested. Early treatment with amphoterecin B and rifampicin may improve survival. (+info)
Flow-injection determination of ornidazole by chemiluminescence detection based on a luminol-ferricyanide reaction.
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A flow-injection analysis (FIA) with a chemiluminescence detection method was developed for the determination of ornidazole based on the inhibition intensity of chemiluminescence from the luminol-ferricyanide system. Under the condition of 1.0 x 10(-3) mol/L luminol and 5.0 x 10(-6) mol/L potassium ferricyanide, the response to the concentration of omidazole is linear from 0.2 microg ml(-1) to 10 microg ml(-1), and a detection limit of 0.05 microg ml(-1) can be obtained. This method has been successfully applied to the determination of omidazole in pharmaceutical preparations. (+info)