The superior efficacy of chloroquine over buparvaquone in reducing the chronic cerebral Toxoplasma gondii cysts load and improving the ultrastructural pathology in an immunocompromised murine model.

Toxoplasma gondii, the etiologic agent of toxoplasmosis, infects about 30 - 50% of the world population. The currently available anti-Toxoplasma agents have serious limitations. The present study aimed to investigate the effects of two antimalarials; buparvaquone (BPQ) and chloroquine (CQ), on immunocompromised mice with chronic cerebral toxoplasmosis, using spiramycin as a reference drug. The assessed parameters included the estimation of mortality rates (MR) among mice of the different study groups, in addition to the examination of the ultrastructural changes in the brain tissues by transmission electron microscopy. The results showed that only CQ treatment could decrease the MR significantly with zero deaths, while both spiramycin and BPQ caused an insignificant reduction of MR compared to the infected non-treated group. All the used drugs decreased the number of mature ruptured cysts significantly compared to the infected non-treated group, while only CQ increased the number of atrophic and necrotic cysts significantly. Furthermore, both spiramycin and BPQ improved the microvasculopathy and neurodegeneration accompanying the infection with different degrees of reactive astrocytosis and neuronal damage with the best results regarding the repair of the microvascular damage with less active glial cells, and normal neurons in the CQ-treated group. In conclusion, this study sheds light on CQ and its excellent impact on treating chronic cerebral toxoplasmosis in an immunocompromised mouse model.

Prognostic significance of genotyping Helicobacter pylori infection in patients in younger age groups with gastric cancer.

BACKGROUND: Malignant tumours of the stomach are common, but the incidence of stomach cancer varies from country to country, probably a result of genetic, epigenetic and environmental factors. Stomach cancer often occurs in older people whose stomachs produce only small quantities of acid. Although infection with Helicobacter pylori has been proven beyond doubt in the aetiopathogenesis of various gastric disorders, not much is known about the genotypes of H pylori infection in early-onset gastric cancer. AIM: To ascertain the genotypes of H pylori in gastric cancer. METHODS: Ninety-two patients were separated into three groups on the basis of their endoscopic findings: group 1, gastric cancer; group 2, gastric ulcer; group 3, non-ulcer dyspepsia. Gastric biopsy specimens were obtained for culture and DNA isolation; additional specimens were taken from subjects with gastric cancer for histopathological analysis. Amplification was performed using specific oligonucleotide primers to obtain genotypic data. Four samples from each group were randomly selected for sequence analysis. RESULTS: Genotypic analysis showed cagT+ve/hrgA+ve/cagA+ve/cagE+ve/vacAs1+ve to be highly prevalent in 79% of cases of H pylori infection. This genotype was found in 88% of subjects in group 1 and 78% in group 2. Intestinal-type adenocarcinoma was found in 35 subjects (83%), 32 (9%) of which harboured this genotype. Sequence analysis showed no significant strain-specific variations. CONCLUSIONS: Certain genotypes of H pylori have higher predictive value for the development of intestinal-type carcinoma at an early age. Genotyping of H pylori may well be a useful tool for screening people at increased risk of developing malignancy.

Effect of a broad spectrum antiparasitic drug "ivermectin" in acute and chronic experimental giardiasis using different dose regimens.

In this study, the maximal excretion of Giardia lamblia cysts was three weeks post infection (p.i). Administration of ivermectin subcutaneously proved to be effective in treating hamsters infected for 2 and 3 weeks respectively. It was found that the dose of 300 microg/kg b.w. was much more efficient than 200 mg/kg b.w. The cure rate was 99.1% in the former, and 98.7% in the later. The difference was statistically significant. In chronic giardiasis where infection was kept for 6 weeks, the cure rate was 99.5% two weeks after treatment with 300 g/kg b.w. of ivermectin. Assessment of cure was performed also by histopathological examination of upper 2/3 of small intestine of the hamsters. Localization and counting of the parasite were carried out immunohistochemically. The mean number of trophozoites decreased markedly after treatment with the large dose either acute or chronic giardiasis.

Effect of the broad spectrum anthelmintic drug flubendazole upon Schistosoma mansoni experimentally infected mice.

The effect of the broad spectrum anthelmintic drug flubendazole (methyl 5-(p-fluorobenzoyl)-2-benzimidazolecarbamate, CAS 31430-15-6), a mebendazole derivative with a molecular weight of 313.29, on Schistosoma mansoni infection in mice was evaluated. Moreover, the relationship between the posttreatment worm burden, hepatic granuloma volume, and serum immunoglobulin profile (immunoglobulin G and immunoglobulin M, IgG and IgM), was also investigated. Two main groups of Swiss albino mice infected with Schistosoma mansoni cercariae were used in the experiment. Group I consisted of infected untreated control mice. The mice of group II were submitted to treatment with flubendazole 100 mg/kg body weight as single oral dose at different time intervals: Group IIa received treatment 24 h before infection. Group IIb received treatment 4 h after infection. Group IIc received treatment 25 days after infection. Mice treated 25 days after infection, compared to those treated in other time intervals, revealed a significant reduction in the recovery of adult schistosomes after portal perfusion (79.5%), a lower immunoglobulin level (IgG and IgM), and the smallest granuloma mean diameter (220.0 +/- 10.3 microns). These data were less salient in mice treated 4 h after, and 24 h before infection.

Effect of Schistosoma mansoni infection on offsprings born from infected mothers.

Offsprings C57BL/6 mice (4 weeks old) coming from either moderately infected (40 S. mansoni cercariae) or heavily infected (100 S. mansoni cerariae) mothers, were exposed to 40 S. mansoni cercariae each. Seven weeks post infection (P.I.), Offsprings were sacrificed. In both groups there was significant reduction in the worm load, both hepatic and intestinal tissue egg count. The oogram profile was not altered. Humoral immune response as regards the level of anti S. mansoni SEA Ab was elevated in both groups in comparison to their parallel controls at 2 weeks post delivery and 7 weeks P.I. The level of antibodies was significantly higher in heavily infected Offsprings than that present in offsprings coming from moderately infected mothers. Delayed footpad swelling and hepatic granuloma size were significantly reduced in both groups comparing with their corresponding controls.

Mutual effect of Schistosoma mansoni infection and pregnancy in experimental C57 BL/6 black mice.

Sixty female C57BL/6 mice were infected with 40 Schistosoma mansoni cercariae each. Seven weeks later, they were mated with normal syngeneic males. Uninfected mice (30) were bred in parallel, and both groups were bred several more times with daily records of pregnancy, delivery and number of offsprings. The number of pregnancy was 146, with 50 survived infants (34.2%) in contrast to 121 pregnancy with 93 survived infants (76.8%) in controls. The outcome of pregnancy was 13% abortion, 10.9% maternal death and 41.7% infanticide. The weight of offspring at 2 and 4 weeks of age was significantly less than in controls (P < 0.01). Again, C57BL/6 (40) female mice were mated, then infected with 100 S. mansoni cercariae each. The results showed that, pregnancy had no effect on bilharzial infection as the total worm burden and distribution, hepatic and intestinal tissue egg count and the oogram profile, were not significantly differ from that in the control group (20). Besides, the immediate footpad swelling was significantly higher but the delayed footpad swelling and the level of antibodies against S. mansoni soluble egg antigen were insignificantly differ from that present in the parallel control (infected but not pregnant). As regards histopathological parameters, although there was insignificant difference in the size of hepatic granuloma, yet there was more collagenous fibrous tissue deposition distributed in-between inflammatory cells specially at the periphery of the granuloma.

Effect of early treatment with praziquantel on serum connective tissue metabolite markers in children and adolescents with intestinal schistosomiasis mansoni.

This work was designed to assess the reflection of early treatment by praziquantel (CAS 55268-74-1, EMBAY 8440, Biltricide) on serum connective tissue metabolite markers (hyaluronic acid and procollagen III peptide) in patients with active intestinal schistosomiasis. Children and adolescent subjects from primary and secondary schools in an endemic area of schistosomiasis mansoni were included. Age-matched subjects from an urban area served as normal controls. All subjects were examined clinically and parasitologically. Detection of hepatitis B seromarkers was also done. The infected subjects were treated with praziquantel at a dose of 60 mg/kg of body weight which was repeated after 4 weeks. Serum hyaluronic acid and procollagen III peptide were measured by radioimmunoassay. High hyaluronic acid was encountered in infected subjects when compared to their respective age-matched controls. Significant decrease of 4 and 8 weeks post-treatment was noted when compared to ist level before treatment. There was no significant change in serum procollagen III peptide on comparing infected subjects to their controls, whereas a significant increase was observed in its level after 4 and 8 weeks post-treatment compared to that before treatment. This work suggests that early treatment of intestinal schistosomiasis with specific chemotherapy (praziquantel) decreases serum hyaluronic acid and increases procollagen III peptide probably via downregulation of granulomatous inflammatory cell reaction and activation of collagenase enzymes, respectively.

Detection of circulating schistosome antigens in serum and urine of schistosomiasis patients and assessment of cure by a monoclonal antibody.

From a panel of monoclonal antibodies (MAb), an IgM monoclonal antibody (7F1/6B) reactive with repetitive epitopes on S. mansoni soluble egg antigen was selected. This MAb was employed both as antigen capture and detection antibody in a sandwich ELISA and had a detection limit < 1 ng S. mansoni SEA/mi. Serum and urine samples were collected from rural students who had S. mansoni (169 subjects) or mixed S. mansoni and S. haematobium (64 subjects) infections. Samples were collected before and at 4, 8 and 12 weeks after praziquantel therapy. Circulating schistosome antigens (CSA) were demonstrated in 90% of sera and 97% of urine samples of S. mansoni group and in 91% of sera and 100% of urine samples of mixed infection group. All sera from 29 uninfected individuals, 30 patients with other parasites and 70% of 55 S. haematobium-infected subjects were negative in this assay. CSA level in serum and urine samples correlated positively with the number of S. mansoni eggs/g stool in both groups. A significant reduction in CSA level was observed in serum and urine samples after praziquantel therapy. By 12 weeks post-treatment, negativity was 98% in sera and 97% in urine of S. mansoni-infected group and 98% in sera and 91% in urine of mixed infection group. The data demonstrate that the use of MAb 7F1/6B for the detection of CSA provides a sensitive method for immunodiagnosis of schistosomiasis and monitoring of cure.

Immunoregulatory potential of exogenous Schistosoma mansoni soluble egg antigen in a model of experimental schistosomiasis--I. Regulation of granuloma formation in vivo.

This study was undertaken to assess the optimum conditions required to reduce the vigorous host granulomatous reaction around Schistosoma mansoni eggs. Soluble schistosomal egg antigen (SEA) at a concentration of 10 or 100 micrograms protein was administered i.p. or i.v. into unprimed C57BL/6 mice. SEA was injected either alone or in combination with cyclophosphamide (CY) 100 or 50 mg/kg via i.p. route. Seven or 14 days later viable eggs of S. mansoni were injected via the tail vein into treated groups and untreated normal controls. Mice were sacrificed 8, 16 and 24 days after the injection of eggs. The lungs were removed for histopathological study, measurement of granuloma diameter and phenotypic analysis of granuloma intralesional T-cell subsets. Compared to untreated controls, the lower concentration of SEA (10 micrograms) administered by the i.v. route 7 days before egg injection, induced a significant reduction in granuloma diameter 16 days after egg injection than that by the i.p. route or at a higher SEA concentration (100 micrograms). Compared to untreated controls, the higher dose of CY (100 mg/kg), given i.p. alone or in combination with 10 micrograms SEA by the i.v. or i.p. route, induced a significant reduction in granuloma diameter, while 50 mg/kg CY did not cause any reduction. The reduction in granuloma diameter by i.v. administration of low SEA concentration alone or in combination with CY IP, was associated with a decrease in the granuloma intralesional L3T4+/Lyt2+ ratio. The decrease in the ratio was due to an increase in Lyt2+ cells. The results suggest that the use of low dose SEA by the i.v. route alone or combined with an immunosuppressive drug ameliorates pathological changes concurrent with S. mansoni infection.

Parasitic infections in primary and secondary schools in Giza Governorate, Egypt.

Four primary and two secondary schools at Kafr Hakeem, El-Mansuria and Berkash villages in Imbaba district were surveyed. Urine and stool specimens of 791 students were examined. Results revealed amoebiasis (22.4%); hymenolepiasis nana (6.2%); ancylostomiasis doudenale (5.7%); ascariasis (1.5%) and enterobiasis (1.1%). Parasites transmitted by autoinfection represented 15.9% of the total infected subjects; those transmitted by the skin penetration 27.2% and by contaminated food 56.9%. There was no statistical difference between primary and secondary school students as regards the rate of infection.

Evaluation of urinalysis reagent strips versus microscopical examination of urine for Schistosoma haematobium.

This study deals with the effectivecess of chemical reagent strips for detection of haematuria and proteinuria in selecting S. haematobium egg positive subjects as compared to microscopical examination of urine. Out of 222 students from primary and secondary rural schools, 191 were S. haematobium and 59 were parasitologically negative. 135 students had a count of less than 50 eggs/10 ml. urine and 56 had more than 50 eggs/10ml. The sensitivity of reagent strips in detecting haematuria was 10% and 36% for the groups with less than and more than 50 eggs/10 ml. of urine respectively. The correspondant microscope figures were 42% and 93% respectively. Proteinuria was detected in 11% and 29% of urines from the groups with less than and more than 50 eggs/10 ml. respectively. The specificity of strips and microscopical examination in detection of haematuria was 100%, while that for proteinuria was 97% as detected by strips. These results show that urinalysis strips cannot be used as an alternative to microscopic examination of urine for the presence of S. haematobium eggs.

Use of Kato and nucleopore techniques for qualitative diagnosis of schistosomiasis.

A comparison on qualitative basis, is attempted between merthiolate-iodine-formaldehyde concentration (MIFC) and Kato thick smear techniques for diagnosis of schistosome eggs in stools. As well, the centrifugation-sedimentation method was compared with the Nucleopore filtration technique for schistosome eggs in urine. Using MIFC and Kato techniques, 149 out of 185 subjects were found to have Schistosoma mansoni infection, 41 of them were diagnosed by Kato alone, while no case was solely MIFC positive. The sensitivity of MIFC compared to kato was 72.3% and both techniques were 100% specific. For diagnosis of S. haematobium infection, 78 out of 103 subjects were positive by centrifugation- sedimentation and/or Nucleopore techniques. 42 of them were diagnosed by Nucleopore alone and none was positive by centrifugation- sedimentation only. The sensitivity of the latter technique was 46.2% and both techniques were 100% specific. The study demonstrates that Kato thick smear and Nucleopore filtration are highly sensitive techniques that can be used for routine qualitative diagnosis of schistosomiasis. Under field conditions, they are qualitatively and quantitatively useful. The Kato technique besides its high sensitivity is very cheap. The only limitation for the Nucleopore technique is its relative high expenses.

Effect of specific chemotherapy on the immune response and resistance to reinfection in experimental Schistosomiasis mansoni.

Mice infected for 45 days with 120 Schistosoma mansoni cercariae and treated with praziquantel in a dose of 500 mg/kg for two consecutive days had a significant lower resistance to reinfection when challenged two weeks after treatment (45% compared to 88% in infected challenged untreated mice). In praziquantel-treated mice, the reduction in the per cent resistance was accompanied by a diminution in the size of hepatic granulomata and its in vivo correlate the delayed foot pad swelling. Moreover, the granuloma proportionate T-cell subset enumeration revealed a significant reduction in the number of T-helper cells. The humoral immune response as measured by the immediate foot pad swelling was not affected by praziquantel. Results reveal besides the diminution of the state in resistance to reinfection after praziquantel, possible involvement of egg-related pathology as a T-cell mediated reaction and as a mechanical obstacle in maintenance of this resistance.

Levamisole restored the compromised state of immunity after specific chemotherapy in experimental schistosomiasis mansoni.

Mice infected for 45 days with 120 Schistosoma mansoni cercariae and treated with levamisole (25 mg/kg subcutaneously) have more efficient acquired immunity when challenged with 240 Schistosoma mansoni cercariae the same day of treatment (97.7% # 87.7% in infected challenged controls). In praziquantel-treated mice (500 mg/kg for 2 days orally), the reduction in the percent resistance (45.5%) was accompanied by a significant diminution in the size of granuloma, delayed foot pad swelling and granuloma proportionate T-helper cells number. Levamisole when given two weeks post praziquantel treatment and with the challenge infection increased the percent resistance to 79.2%. The increase in percent resistance recorded in mice receiving both praziquantel and levamisole was accompanied by restoration of granuloma size, delayed foot pad swelling and granuloma proportionate T-helper cells number to infected challenged untreated control values. Results reveal-beside efficacy of levamisole as immunoregulant in schistosome immunity--a possible role for the granuloma as a T-cell mediated response in maintenance of immunity.