Novel triazolo[4,3-a]quinazolinone and bis-triazolo[4,3-a:4,3'-c]quinazolines: synthesis and antitoxoplasmosis effect.

Several quinazoline derivatives containing substituted thiosemicarbazido and S-methylisothiosemicarbazido groups at the 2-position and at both the 2- and 4-positions have been synthesized. Treatment of the S-methylthiosemicarbazides with morpholine or diethylamine did not give the corresponding guanidines. Instead, they underwent cyclodesulfurization into the condensed ring systems, [1,2,4]triazolo[4,3-a]quinazolinones and bis-[1,2,4]triazolo[4,3-a:4'.3'-c]quinazolines. Evaluation of the products for antitoxoplasmosis effect by studying the ultrastructure morphology of the organisms using scanning electron microscopy (SEM) indicated their efficacy in causing structural deformity of Toxoplasma gondii. Such a deformity plays an important role in obstructing the entry of the organisms into host cells.

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.

Confirmation of clinical differentiation of three Leishmania strains by computerized image analyser system.

Three human strains of Leishmania, one visceral and two cutaneous leishmaniasis were prepared from both culture and tissue of infected animals and subjected to analysis by computerised image analyser system. The results showed differences in the morphology and nucleic acid contents of the three strains.

Evidence of sexual reproduction in the protozoan parasite Leishmania of the Old World.

Three Leishmania strains of the old world were the subject of this study. Both the amastigote and promastigote stages were subjected to staining by Feulgen procedure and examined by computerized image analyser system to determine their nuclear DNA content. Results of this study showed that, in the promastigote stage there is a single cell population, whereas in the amastigote stage there are two population of parasite nuclei. One with low level of DNA resembling that of the promastigote and a second population with double DNA level. This latter formed when apparently 2 nuclei fused and form one with double DNA level. The data obtained in the present study further indicate that Leishmania of the old world can undergo nuclear fusion which is a strong evidence for the presence of sexual reproduction in the parasite.

Detection of Trichinella pseudospiralis antigen in the parenteral phase in experimentally infected mice.

Antigen distribution of T. pseudospiralis in muscles was studied at 10 days, 2,3 and 5 weeks post infection. Immunocytolocalization of antigen in the muscle was performed by peroxidase antiperoxidase (PAP) and immunogold silver staining techniques. Weak positive reaction of the stichosome and the cuticle was observed at 10 days post-infection which increased to attain its highest level in the fully infective stage larvae 3 and 5 weeks post infection. The intensity of staining reaction in the cytoplasm and nucleoplasm of infected host cell and surrounding tissue was highest at 5 weeks p.i. The small nuclei of the host cells and the inflammatory cells were unstained.

Detection of circulating Trichinella pseudospiralis antigen by enzyme linked immunosorbant assay (ELISA).

A modified double antibody sandwich ELISA was used as a sensitive technique for demonstrating the appearance of circulating antigen of T. pseudospiralis in the sera of infected mice. The sera were tested at 5 days, 2, 4, 6, 7, 8, 10 and 12 weeks P.I. The antigen was first detected on the 5th day P.I., its level increased to reach the 1st peak at 4 weeks, then declined at 6 weeks. A second peak was observed at 8th weeks followed by a sharp decline to give negative OD reading at 10th week and increased to a moderate level at 12 weeks P.I.

The effect of flubendazole on the course of Trichinella spiralis infection in mice: parasitological study.

This work planned to study the effect of flubendazole against different stages of Trichinella spiralis infection in mice. Three groups of experimental animals were examined: control group, group I treated three days post infection and group II treated four week post infection. In group I, flubendazole was shown to be a very potent agent in killing Trichinella spiralis adults and larvae, when given orally in a dose of 20 mg/kg for five consecutive days. This is evidenced by the significant reduction in number, length of the female and reproductive capacity as well as the absence of the muscle larvae. However, in group II, the effect of the drug although still significant yet diminished in all parameters as compared to the early treatment. These results evoke ideas for further design of other treatment and control of the disease.

Detection of Trichinella pseudospiralis antigen in the enteral phase in experimentally infected mice.

The distribution of T. pseudospiralis antigen in tissue sections of the intestine of infected mice was studied at different intervals (10, 21, 35 hours and 10 days post-infection (P.I.). Immunocytolocalization of antigen in the intestine was done by peroxidase antiperoxidase staining technique. Positive staining reaction of the enterocytes was noted in all durations examined. The mononuclear cells of the lamina propria were positively stained at 10 hrs P.I. while patchy staining of muscularis mucosa was observed at 10 days P.I. The present study revealed intense staining reaction in the stichosome and the cuticle of 10 hrs-old larvae L1, the intensity of the reaction decreased throughout the worm development, until it almost disappeared at 10 days P.I. The gut lining and its occupying substance were positive throughout the enteral phase. Intense staining reaction of the hypodermal cells was observed in L2, L3 and adult stage worm. The genital primordium was weakly stained in the larval stages while the male and female reproductive systems were moderately stained at the adult stage.

Pathologic and ultrastructure characterization of two different strains of Schistosoma mansoni.

Schistosomiasis constitutes one of the major endemic diseases in both African and Asian countries. There are numerous strains of Schistosoma mansoni. Although there is similarity between their life cycles, yet there are many differences in the morphology of the adult worms, their pathogenecity, their infectivity and their ultrastructural features. This study was performed on albino mice infected with both Egyptian and Saudi strains, to investigate the characteristic differences between them. It was found that at the eight week post-infection, the highest amount of egg deposition and granuloma formation was present in the liver of infected mice with the Egyptian strain; while it was highest in the small intestine of those infected with the Saudi strain, followed by the liver and the large intestine. Although no prominent histopathologic differences were detected in the cellular and tissue reactions in the resulting granulomata surrounding eggs, yet marked differences were observed in the surface topography of the tegument and distribution of papillae, pattern of ridges, microvilli, and spines of both strains. These differences were more pronounced in males. It might be concluded from this study that such differences are due to strain variation, biological and morphological characteristics of Schistosoma mansoni, and could be considered as a baseline for further experimental studies.

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.

Schistosoma haematobium (Egyptian strain) transmission microscopy of normal and praziquantel treated worms.

The ultrastructure of the tegument and subtegumental structures of S. haematobium worms was examined by TEM. The effect of praziquantel on residual worms which remained after a curative dose was also studied. The male S. haematobium worms were characterized by deep tortuous pits and sharp apically directed spines. Spherical and elliptical bodies were also observed. The esophageal tegument was described. The effect of praziquantel on the male worms revealed flattening of spines and their disappearance in some regions as well as disruption and vacuolization of the tegument in others.

Maternal transfer of resistance to Schistosoma mansoni in offspring born to Trichinella-infected mice.

This study was performed to investigate the presence of maternal transfer of resistance to S. mansoni in mice born to Trichinella-infected mothers. T. spiralis-born mice were infected with S. mansoni cercariae. Parasitological study was done at eight and twelve weeks post-schistosomal infection. There was a significant reduction in the number of schistosomes (44.4%), in the liver egg count (38.9%) and in the intestinal egg count (50.46%). Histopathologically, there was a reduction in the number and size of granulomata at the different time intervals, as well as acceleration in the inflammatory reaction.

Evaluation of enzyme-linked immunosorbent assay and counter-current immunoelectrophoresis in diagnosis of experimental trichinosis.

Definite diagnosis of trichinosisis mainly by direct demonstration of larvae, however, these methods are neither feasible nor sensitive. Thus, confirmation relies mainly on positive serology. In this study, enzyme-linked immunosorbent assay (ELISA) and counter-current immunoelectrophoresis (CIEP) using crude larval antigen were assessed as a tool in the diagnosis of trichinosis. Sera were tested one, two, five, eight, and twelve weeks post-infection. It was found that ELISA was positive in all tested sera from the second till the 12th week (100% sensitivity). As regards CIEF, 36% of the sera were positive two weeks post-infection, while all sera were positive at 5 and 8 weeks. Ninety per cent of the tested sera gave positive results at the 12th week post-infection. ELISA proved to be more sensitive in diagnosing trichinosis both early and late in infection, while CIEP test was more specific since no false positive results were noticed.

Scanning electron microscopy of normal and praziquantel treated S. haematobium worms (Egyptian strain).

The ultrastructure of the tegument of S. haematobium was examined before and after treatment with Praziquantel using scanning electron microscopy. The surface of the adult male worms prior to treatment showed numerous tubercles with apically directed spines and the lateral border showed highly pitted folds. The oral and ventral suckers showed well developed spines. Praziquantel administration caused various structural changes in the various groups studied. Blebs and spine deformities appeared as early as half an hr. after administration. Changes were also observed when the drug was administered prior to worm maturation resulting in generalized deformities in the worms which survived treatment, loss of spines and tegumental swellings.

Effect of cyclosporin A on trichinosis. A histochemical study.

The aim of this work was to reveal the possible effect of the drug CSA treatment in experimental trichinosis on some important tissue enzymes; alklline and acid phosphatases, succinic dehydrogenase and alpha-esterase. This study revealed that the effect of the drug was apparently evident on succinic dehydrogenase enzyme which returns back to the control. The diminished acid phosphatase activity showed the effect of the drug on the T-cells.

Preparation and use of monoclonal antibodies in the detection of Trichinella spiralis circulating antigen.

In the present study, a trial was made to evaluate the monoclonal antibody produced as a tool in the detection of circulating antigen. For the preparation of monoclonal antibodies, four Balb/C mice were immunized with Trichinella spiralis larvae. Immunized spleen cells were prepared and a suitable mutant NS1 myeloma cell line was used for fusion. Eighty white swiss albino mice were orally infected with 500 L1 T. spiralis larvae. Their serum was collected at different periods i.e. 5, 11, 18 and 28 days post infection for the detection of circulating antigen which was done by the ELISA technique. Circulating antigen could not be detected on day 5 post infection, while on day 11 it was clearly identified; on day 18 it could be detected but at a lesser O.D. reading however the antigen disappeared completely on the 28th day. This study confirmed that monoclonal antibodies may be a valuable tool in the early diagnosis of trichinosis by the detection of specific antigens, even in small amounts whenever present in the circulation.