Synthesis of new mercaptotriazoles with potential antibilharzial activity.

Several 3-mercaptotriazoles with the 8-hydroxyquinoline moiety in the 5-position were prepared and tested for antiparasitic activity. Preliminary biological tests on experimentally infected mice with Schistosoma mansoni worms revealed that the new compounds possess potent schistosomicidal activity.

Experimental conversion of virulent RH Toxoplasma gondii tachyzoites in vitro.

We aimed to induce conversion of RH-stain tachyzoites to bradyzoites by changing the pH of the culture medium. Alkalization of the medium to pH 8 induced morphological changes in the cultured tachyzoites. The majority of the organism increased in size and changed from a regular crescent shape to a rounded or ovoid shape. Cyst-like structures were formed. Using a computerized image analyser, significant differences in the size of the whole organisms and in their nuclei were observed compared to the control group. The converted organisms also showed significant differences from the control group by quantitative DNA analysis, and did not infect mice.

A rapid diagnostic test for Trichomonas vaginalis infection.

The applicability of the quantitative buffy coat tube test (QBC) for diagnosis of T. vaginalis was studied. The results of the QBC tube test was compared with that of the wet mount examination in 60 women having genital infection. The cases were selected from outpatient clinic of El-Shatby University Hospital T. vaginalis was identified by QBC tube test in 24 cases out of 60 while the wet mount smear, it was detected in 21 cases. The sensitivity of the QBC tube test was 100% and the specificity was 92.3%. It was found that the QBC tube test seems to have a place in the routine diagnosis of T. vaginalis.

Seroprevalence of Toxoplasma and cytomegalovirus in complicated pregnancies.

Anti-Toxoplasma and anti-cytomegalovirus (CMV) antibodies were sought in 200 pregnant women (100 with complicated pregnancies and 100 matched controls without any hazards) by ELISA test. Sixty-five per cent of the women with complicated pregnancies had Toxoplasma antibodies, while 51% had CMV antibodies. Toxoplasma seroprevalence alone was higher in women with intrauterine foetal death (IUFD) (80%). CMV seroprevalence alone was higher in women with premature labour (44.4%) and women with stillbirth (40%). Seroprevalence of both Toxoplasma and CMV was clearly higher in women with abortion (55.7%). Seroprevalence of Toxoplasma and CMV in the control group was 6% and 30%, respectively. These data confirm that Toxoplasma and CMV are important causes of complicated pregnancy.

Opsonization and intracellular killing of Toxoplasma gondii by human mononuclear phagocytes.

Macrophages and monocytes have been shown to have an important role in the defence mechanism against Taxoplasma gondii infection. Antibodies in the presence of complement have been found capable of killing extracellular T. gondii. This study demonstrated that tachyzoites in the presence of antitoxoplasma antibodies with complement were detected in 39-58% of monocytes that had phagocytosed them and the mean number of Toxoplasma tachyzoites in this group was significantly low one hour post infection, while only 10-25% of monocytes phagocytosed Toxoplasma tachyzoites in absence of antibodies and complement with significant high number of replicated tachyzoites. This indicated that specific antibodies had a strong opsonizing action. Complement alone was weak in increasing the phagocytic activity.

Therapeutic effect of triclabendazole in patients with fascioliasis in Egypt. A preliminary study.

Human fascioliasis is becoming an increasingly important clinical and epidemiological problem in Egypt. However, the treatment of the disease presents certain difficulties as the usual known drugs such as emetine hydrochloride and praziquantel do not cure fascioliasis using a single dose. Recently, ten cases were presented with a variability of clinical manifestations suggesting fascioliasis. The indirect haemagglutination test (IHA) was positive with high eosinophilia. SGOT and SGPT were normal & no signs of heart or kidney diseases. After taking the consent of the patients, triclabendazole, a novel benzimidazole compound was given orally in a single dose of 10mg/kg body weight. The results hereby revealed that the general condition and all signs of the patients were ameliorated with a drop in the eosinophilic count, which returned to normal after 2-3 months. Being safe, reliable and easy to administer, triclabendazole is ought to be considered for the treatment of human fascioliasis.

ELISA screening for Lyme disease in children with chronic arthritis.

One hundred patients, aged 6-15 years and presented to El-Shatby University Children's Hospital with chronic/recurrent arthritis and skin lesions suggestive of erythema chronicum migrans (ECM), were investigated for presence of IgG antibodies against Borrelia burgdorferi flagellum antigen ELISA test. Four cases yielded positive serum samples which were true positive cases as they showed negative Venereal Disease Research Laboratory (VDRL) test. Ticks collected from domestic animals from the houses of serologically positive patients were found belonging to hard tick: Rhipicephalus sanguineus. Based on clinical ground, only one case was strongly suspected to have Lyme disease due to the presence of the distinctive skin lesion (ECM) while the other three cases were not diagnosed till the results of serological test. This study provides serological evidence concerning the presence of Lyme disease in Egypt. Further efforts of identify its prevalence, various clinical presentations, vectors and animal hosts are warranted.

Detection of circulating antigens in blood to evaluate treatment of fascioliasis.

This work was designed to assess cure of human fascioliasis after triclabendazole treatment by detection of Fasciola antigen by a modified double antibody sandwich ELISA technique. The results showed that the test detected the antigen in the sera of all studied cases before treatment, while no antigen was detected after treatment. The results may suggest that antigen detection provides an accurate tool for diagnosis as well as the assessment of cure.

Effect of interleukin-2 on experimental acute toxoplasmosis.

The traditional treatment of toxoplasmosis involves the use of pyrimethamine and sulphadiazine. This combination has a teratogenic effect and its use is limited especially in immunosuppressed cases. Spiramycin used safely during pregnancy is also not effective because it is toxoplasmistatic only. The potential efficiency of alternative immunotherapy was assessed. The present study was undertaken to evaluate the effect of exogenously supplied IL-2 on T. gondii infected mice. IL-2 was administered after infection (on days +2, +4, +6, +8), before and after infection (on days -3, -1, +2, +4, +6) and before infection (on days -8, -6, -4, -2). The date of infection was considered zero. Assessment of its effect was through: a) Parasitological study which included: parasite count, differentiation between living and dead tachyzoites and death rate of infection mice. b) Immunological study: detection of circulating antigen on the 3rd, 5th, 7th and 9th day p.i. The results showed that IL-2 was most effective when administered before and after infection in the form of significant reduction in parasitic count, least number of living tachyzoites, significant reduction in the death rate of infected mice and delayed appearance of circulating antigen with reduction in its level.

Opportunistic intestinal protozoa in chronic diarrhoeic immunosuppressed patients.

Chronic diarrhoea accompanied by weight loss is a common and often debilitating problem in immunocompromized patients, receiving chemotherapeutic agents. In these patients, the intestinal opportunistic parasites probably played a major role in causing this clinical manifestation. The present work, aims to search for these parasites. Special stains for each parasite were used to differentiate it easily from the fecal elements, obviating the need for diagnostic invasive techniques especially used in microsporidial infection. The detected parasites were, Giardia lamblia (17.7%) best seen by iron haematoxylin stain. Coccidian oocysts (Cryptosporidia; 13.3% Isospora belli; 2.2%) were clearly seen by using Ziehl-Neelsen and Chromotrope-based stains. The Gram positive spores of Enterocytozoon bieneusi were (4.4%) and best seen by using chromotrope-based stain, where as Giemsa failed in their diagnosis.

Intestinal parasitic infection among sewage workers in Alexandria, Egypt.

This research was conducted to study the risk of intestinal parasitic infections among sewage workers. A hundred sewage workers in Alexandria and another hundred as control group not exposed to sewage were selected for this research. The results indicated that sewage workers were at a higher risk of developing intestinal parasitic infection especially Ascariasis and Amoebiasis. Nail examination revealed that sewage workers were at a higher risk of infection by Entrobius vermicularis.

Schistosoma mansoni: a comparative study on two cercarial transformation methods.

An agar: gelatin plate method, incorporating varying concentrations of linoleate was devised to measure cercarial penetration and transformation in vitro. Schistosoma mansoni cercariae were stimulated over a wide range of linoleate concentrations, while the transformation process occurred over a narrow range. Penetration rates rose gradually until at linoleate concentrations of 0.3 mM and greater, where penetration approached 100% while transformation just started to occur. The latter then reached maximum (90%) at 3 mM. This optimal concentration of linoleate leading to maximal transformation was then compared with a mechanical transformation method in relation to proteolytic activity and nuclear content. It was found that, proteolytic activity was higher by the chemical than by the mechanical transformation method. The nuclear content decreased by both techniques. This decrease was greater when the mechanical transformation method was applied.

Measurement of respiratory burst of TNF and IL-1 cytokine activated murine peritoneal macrophages challenged with Toxoplasma gondii.

In vitro activation of murine peritoneal macrophages by TNF and IL-I cytokines resulted in significant elevation of respiratory burst (toxic oxygen metabolites) in comparison to inactivated cells when challenged with Toxoplasma gondii. These oxygen metabolites have been known to have microbicidal activity and so, they may be the direct cause of intracellular killing of T. gondii tachyzoites. The level of these oxygen metabolites was measured by chemiluminescence index. A possible biotherapeutic role for TNF and IL-1, through this mechanism, was also emphasized.

Effect of toxoplasmosis on experimental schistosomiasis.

One hundred and twenty Swiss albino mice were infected with avirulent strain of Toxoplasma gondii (Czechoslovakian strain) challenged with Schistosoma mansoni at different intervals of one week, one month, and two months. Worm load, egg count, oogram pattern and liver and spleen weight were assessed for each mouse. Toxoplasmosis induced a significant resistance to Schistosoma mansoni challenge infection as evidenced by the reduction in worm load, egg count and changes in oogram pattern. The mean liver weights of concomitantly infected mice was increased which was not significantly different from their corresponding Schistosoma infected controls but the increase in spleen weight was significant.

Effect of mebendazole and ivermectin in experimental hepatic capillariasis: parasitological, scanning electron microscopy and immunological studies.

In this study, mebendazole and ivermectin were tried during three different phases of C. hepatica infection. At an early phase, when immature forms were present both drugs were effective in causing destruction and degeneration of the larvae, thus preventing subsequent growth and maturation and consequently the complete absence of eggs. During the second phase, which is found to be the most critical period the two drugs used led to degeneration and resorption of most of adult worms. In the third phase both mebendazole and ivermectin were effective in decreasing the mean number of eggs. After treatment the topographic changes were in the form of disorganized cuticle of the worms and absence of surface uniformity. Such a disorganized cuticle is vulnerable to be attacked. C. hepatica eggs showed irregularities and longitudinal grooves indicated shrinkage of the shell. The effect of the two drugs indicate that both of them were effective in the treatment of hepatic capillariasis.

Immunological and histopathological studies on the effect of toxoplasmosis in experimental schistosomiasis.

One hundred and twenty Swiss albino mice were infected with avirulent strain of Toxoplasma gondii. Then challenged with Schistosoma mansoni at different time intervals of one week, one month and two months. The immunological and histopathological changes were assessed for each mouse. The results showed that toxoplasmosis caused specific humoral and cellular immunosuppression to Schistosoma mansoni infection.

Effect of mebendazole and ivermectin in experimental hepatic capillariasis B: histopathological and ultrastructural studies.

Although, rodents are the principle hosts of C. hepatica both true and spurious human infections have been reported. Over half of the reported cases, resulted in death with hepatic capillariasis being discovered at autopsy; even in cases which the infection was detected at laparotomy or liver biopsy, the patient died due to the lack of suitable treatment. Therefore, studies on experimental C. hepatica in mice were carried out on the way of reaching a full program for treatment. The drugs used were mebendazole and ivermectin. The alterations noted in the egg shell by TEM suggest the effectiveness of the drugs used, the eggs appeared to be deformed; the outer shell was broken and distorted in several places. Many pillars were fragmented. The inner layer was also affected, where it showed destruction of its outer lamellae. Ultrastructural changes in the liver cells showed dysplastic changes. It may be a sequelae of mechanical injury or direct antigenic insult of the parasite or their toxins on the liver cells. During the course of the present work, it was noticed that most of the granulomata were in the fibrotic stage denoting acceleration in the process of healing of the lesions and no freshly deposited ova and hence no active cellular granuloma.