Cysteine proteases inhibitors [phenyl vinyl sulfone and valproic acid] in treatment of schistosomiasis mansoni-infected mice: an experimental study to evaluate their role in comparison to praziquantel

The emerged resistance to praziquantel [PZQ] in treatment of schistosomiasis necessitates the search for novel drugs. Cysteine proteases inhibitors [CPIs] have shown promising results in either parasitic infections or non-parasitic diseases. The study aimed to evaluate the therapeutic effects of two CPIs: phenyl vinyl sulfone [PVS] and valproic acid [VA] in comparison to PZQ in S. mansoni-experimentally infected mice. Swiss albino mice were experimentally infected with S. mansoni cercariae. The mice were divided into 4 groups [25 mice each], and G1 mice were not treated and used as control group. Mice of G2, G3 and G4 were treated by the evaluated drugs [PVS, VA and PZQ, respectively] at the end of the 6[th] week post infection [PI]. The evaluating parameters were 1] fecal egg count, 2] worm burden, 3] tissue egg count, 4] oogram pattern and 5] hepatic granuloma number and size. The results showed that by the end of 10[th] week PI, PZQ was the most effective drug resulting in decrease worm burden in the portal vein, increase proportion of dead eggs in the oogram pattern, decrease in the hepatic egg count and decrease in granuloma numbers. On the other hand, the granuloma diameter was smallest in PVS treated group compared to the other groups. CPIs have a relative fair favorable therapeutic outcome on schistosomiasis mansoni with the advantage of being novel drugs with no therapeutic resistance, especially PVS which showed an added specific anti-immunopathological effect reflected by the small hepatic granuloma size

Evaluation of the nitric oxide activity against Blastocystis hominis in vitro and in vivo

The effect of exogenous nitric oxide [NO] on growth, viability and ultra-structural of B. hominis was assessed in vitro by sodium nitrite [NaNO[2]] in 0.6 mM, 0.8 mM and 1 mM concentrations. The viability of B. hominis was identified using neutral red stain. The role of NO as an endogenous oxidant was assessed by identifying its level in cecum tissue, ileum tissue, blood and stool elutes of mice infected with B. hominis symptomatic human isolates using reactive nitrogen assay compared to control. In vitro study revealed that NaNO[2] inhibited the growth and decreased viability of B. hominis with minimal lethal concentration dose 1 mM on the 4[th] day while, minimal effects were detected with 0.6 and 0.8 mM. Transmission electron microscopy study proved that apoptotic-like features were observed in growing axenic culture of B. hominis upon exposure to NaNO[2]. These changes were not only found on the vacuolar [central body] form but also they were detected on granular, multi-vacuolar and cyst forms. In vivo study proved that high levels of NO were found in infected mice compared to low changes in control group. The high levels were in cecum tissue particularly. The mean levels of NO among infected mice were 211.8 +/- 20.7 micro M in cecum, 90.4 +/- 11.6 micro M in ileum, 60.1 +/- 4.7 micro M in blood and 63.6 +/- 7.3 micro M in stool elutes while, the mean levels of NO in control mice were 70.2 +/- 3.1 in cecum, 67.8 +/- 4.7 micro M in ileum, 30.9 +/- 4.2 micro M in blood and 28.1 +/- 2.9 micro M in stool elutes. The differences were statistically highly significant. NO-donor drugs proved useful in treatment and increase the host resistance to B. hominis

Effect of exogenous adminstration of anti-oxidants on Blastocystis hominis in vivo

The effect of exogenous administration of antioxidant [Anttox] on the course of B. hominis in experimentally infected mice was studied. B. hominis isolates were obtained from 10 gastrointestinal symptomatic adult patients. Three groups of 30 infected mice [3/isolate] were used. GI was untreated infected, GII was treated by antox for 4 weeks after infection diagnosis [treatment strategy], and GIII antox treated by antox for 4 weeks before infection [prophylactic strategy]. Mild pathological changes were detected on 13.4%, 19.9% and 86.8% of mice in Gs I, II and III, respectively. Moderate pathological changes were found in 29.9%, 26.6% and 6.6% of mice in Gs I, II and III, respectively. While, the majority of severe pathological changes were in Gs I and II [56.7% and 53.5%] as compared to GIII [6.6%]. Meanwhile, 86.8% of mice in GIII had B. hominis forms >10/high power field compared to 3.3% in Gs I and II, respectively. Although 19.8% of mice in GII were positive for B. hominis by direct smear, no growth resulted in vitro and all the forms were non-viable by using neutral red stain. All the differences were statistically significant. So, antioxidant exacerbated B. hominis intensity but it decreased the pathological changes

Real-time PCR and flow cytometry in detection of cyclospora oocysts in fecal samples of symptomatic and asymptomatic pediatrics patients

The magnitude of Cyclospora oocysts excretion in relation to infection intensity among cyclosporiasis patients was assessed using flow cytometry and quantitative real-time PCR [RT-PCR]. Oocysts from stool samples of 25 [14.8%] gastro-intestinal symptomatic pediatrics patients [169] and of 10 [2.8%] asymptomatic gastrointestinal ones [350] were identified by modified Ziehl-Neelsen [MZN] and modified Acid Fast Trichrome [MAFT] staining methods and confirmed by its auto-fluorescent characterizations. Also, 10 infants with negative stool samples were selected as controls. The intensity of infection was calculated as number of oocysts/200 microscopic filed with immersion 400. Flow cytometry and RT-PCR assessed relation between symptoms and oocysts excretions compared to MZN and MAFT. The infection severity in symptomatic patients were identified by MZN and MAFT as mild [16%], moderate [24%] and severe [60%]. All asymptomatic patients had mild infection. Flow cytometry was done for stool samples and 100% Cyclospora oocysts were in symptomatic and asymptomatic patients. None was detected in controls, RT-PCR was done for stools with both a species-specific primer set and dual fluorescent labeled Cyclospora cayetanensis hybridization probe by unique regions of 18S rRNA gene sequence. DNA of C. cayetanensis was in 100% of symptomatic and asymptomatic patients and in 20% of controls. In repetitive examination of stools Cyclospora oocysts were neither detected by staining nor flow cytometry. Based on oocysts counts, no differences were found between flow cytometry and RT-PCR in compared to staining methods

Molecular characterization of Egyptian trichomonas vaginalis clinical isolates by HSP70 restriction fragment length polymorphism

Molecular typing of 20 Egyptian Trichomonas vaginalis clinical isolates was performed using the Restriction Fragment Length Polymorphism [RFLP] analysis employing a probe from the heat-inducible cytoplasmic HSP70 gene family hybridized with EcoR I-digested genomic DNA. In each of the isolates tested 5 to 6 distinct DNA fragments ranging from 2.7 Kb to 7.5 Kb in size were detected. Analysis of 13 isolates from symptomatic and 7 isolates from asymptomatic women revealed 6 distinct RFLP pattern subtypes of T. vaginalis. Eleven isolates [55%] showed the same RFLP pattern, teen of them [90.9%] were from symptomatic patients. T. vaginalis virus [TVV] was present in 7 isolates [35%]. Only one isolate was considered resistant to Metronidazole. There were no relations between TVV infection or Metronidazole susceptibility and RFLP subtypes