[Anti-fecundity effect of soluble immature egg antigen of Schistosoma japonicum in mice].

OBJECTIVE: To study anti-female fecundity effect in mice immunized with soluble immature egg antigen (SIEA) of Schistosoma japonicum, and observe possible mechanism. METHODS: Immature eggs were collected from the liver of a rabbit 34 days after being infected with 3000 cercariae of S. japonicum, and soluble antigen was prepared routinely. 20 ICR mice were divided randomly to 2 groups. 11 mice were immunized with SIEA (100 microg per mouse) and Freund adjuvant and the other 9 were injected with equal volume of sterile normal saline and Freund adjuvant as control. All mice received injection 5 times in 2 weeks interval. One week following the last vaccination, mice were challenged with 30 +/- 2 cercariae of S. japonicum Yunnan isolate. Feces were collected on day 45. All mice were sacrificed on day 46. The number of worms collected, number of eggs in feces, female uterus and liver, and the number of egg granulomas on the liver surface were compared between the 2 groups. The vitelline gland of female and testes of male worms were examined by transmission electron microscopy. RESULTS: There was no significant difference on the worm number between the immunized group and control (P > 0.05). The eggs per gram feces and liver, eggs in uterus per female, and egg granulomas on the liver surface were (56.68 +/- 24.78), (5 826 +/- 437), (49.94 +/- 12.53) and (10.04 +/- 1.13)/0.25 cm2, respectively in immunized group, while in control group these were (89.93 +/- 32.18), (10016 +/- 3541), (76.54 +/- 19.77) and (19.22 +/- 2.45)/0.25 cm2 respectively, all with significant difference (P < 0.05). Ultrastructure of the reproductive organs of paired adult worms showed that mature vitelline cells and lipid droplets in the cytoplasm of the cells decreased in the vitelline glands of immunized mice. More sustentacular cells and fewer spermatids were seen in testes of immunized mice. Vacuoles were seen in the cytoplasm of vitelline cells and sustentacular cells. CONCLUSION: The results indicated that SIEA may have an anti-fecundity effect possibly through inhibiting the maturation of germinal cells.

Effects of frozen storage on the structure of sarcocysts in pig muscle and implications in taxonomic studies.

UNLABELLED: The morphology of the cyst wall of Sarcocystis has unique characteristics that can be used in species identification. To find a suitable way to preserve Sarcocystis cyst samples for species identification, by light microscopy and electron microscopy, we recorded the morphological changes in the cysts of Sarcocystis suihominis and Sarcocystis miescheriana from pig muscle, induced by storage at -20 degrees C. Comparisons were made between fresh cysts and those subjected to frozen storage for periods of 3 days, 20 days and 30 days. RESULTS: cyst wall of the two Sarcocystis species appeared unaffected by storage. There was no obvious change in the length, nor in the width of the protrusions after storage (P>0.05), but the structure of the bradyzoite in the sarcocyst was in many cases disintegrated at -20 degrees C in 20 days for S. miescheriana and 30 days for S. suihominis. To our knowledge this is the first report that Sarcocystis cyst in muscle can be stored at -20 degrees C before and remain suitable for ultrastructural morphological study. Consequently, this paper proposes freezing as a convenient storage method for samples used in taxonomic studies of Sarcocystis.

Muscarinic M2 antagonists: anthranilamide derivatives with exceptional selectivity and in vivo activity.

Anthranilamide analogues such as 23 are potent and highly selective muscarinic M2 antagonists that also show good oral bioavailability and in vivo activity.