Immune complex mediated lesions in experimental Kala azar: an ultrastructural study.

Immune complexes play an important role in causation of renal lesions in various diseases. Circulating immune comlexes (CIC) are described in Kala azar. Role of CIC in pathogenesis of Kalaazar is discussed in present study. BALB/C mice were experimentally infected with L. donovani promastigotes. After visceralisation of infection, sera and kidneys of infected mice were preserved. Leishmanial antigen specific CIC could be demonstrated in 100% of infected mice by PEG ELISA, while they were absent in control mice. Ultrastructural pattern of renal lesions in infected mice showed presence of focal small electron dense deposits in glomerular basement membrane and subepithelial space, resembling immune complexes (humps). Rarely subendothelial and mesangial hypercellularity was present. These findings point towards a definite role of CIC in pathogenesis of renal lesions in Kalaazar.

Ultrastructural study on the antileishmanial effect of 1,2-dimethyl-3-methoxy carbonyl-4-(2-nitro-4,5-dimethoxyphenyl) pyrrole in hamsters.

An ultrastructure study was carried out on the effect of a standard drug sodium stibogluconate and a newly identified active CDRI compound 87/305 [1,2-dimethyl-3-methoxy carbonyl-4-(2-nitro-4,5-dimethoxyphenyl) pyrrole] on amastigotes of Leishmania donovani in macrophage cells of spleen of infected hamsters. While Na-stibogluconate exerted its effect by activating the digestion capacity of host macrophages, compound 87/305 was directly lethal to the parasites without, exerting any effect on the host cells.

Biochemical and ultrastructural studies induced by phanquone on Entamoeba histolytica NIH-200.

The action of phanquone on the incorporation of (14C)1-DL-valine and (14C)-8-adenine in TCA insoluble fractions of Entamoeba histolytica was examined as indices of RNA and protein synthesis respectively. The former was found to show greater sensitivity to the drug in terms of the effect manifested in the dose response curves for these parameters. Electron microscopic investigations with increasing concentrations of the drug demonstrated progressive vacuolization with concomitant dissolution of ribosomal helices. The drug had no significant effect on nucleus and plasma membrane even at concentration as high as 200 micrograms/ml.

Action of metronidazole on Entamoeba histolytica: an ultrastructural study.

Metronidazole (19 micrograms/ml) caused progressive increase in vacuolization in Entamoeba histolytica cells with disintegration of its plasma membrane leading to almost complete disappearance of the latter within 3 hours. The drug also induced formation of helical ribosomal aggregates in the cytoplasm and disappearance of button like structures inside the nucleus.

Ontogeny of ookinete of Plasmodium berghei (NK 65): a scanning electron microscopic study.

The ontogeny of ookinete of Plasmodium berghei (NK 65) was studied in vector Anopheles stephensi fed on infected Mastomys natalensis. The round zygote transformed into an ookinete after passing through following stages-1 gram-seed shaped zygote, 2 comma-shaped stage, 3 semilunar and 4 banana shaped ookinete. Each fully formed ookinete had a 'Conule' at the anterior end of the body. In some ookinetes under SEM a depression was observed in the posterior half of the body. The function of the depression was not known.

Methyl 5(6)-(alpha-hydroxyphenyl methyl) benzimidazole-2-carbamate and cysticercosis: chemotherapeutic and electron microscopic studies.

Methyl 5(6)-(alpha-hydroxyphenyl methyl) benzimidazole-2-carbamate, a major metabolite of mebendazole was evaluated against Cysticercus fasciolaria (larval form of Taenia taeniaeformis) in rats. The metabolite was assessed in various doses. A regimen of 50 mg/kg x 10 (ip), given one day apart, was found to be most effective and killed all the mature cysticerci. On developing cysts, the treatment was initiated in two schedules; 5 days prior to (d-5 to d-1) and 5 days after (d + 6 to d + 10) administration of T. taeniaeformis eggs to rats. The later protocol with 100 mg/kg x 5 dose (ip) resulted in 95% inhibition in the establishment of cysticerci. Activity of mebendazole against mature cysts was parallel to metabolite whereas against developing cysts, it was inferior. The time related topographical changes that occurred in mature C. fasciolaris after treatment with metabolite (50 mg/kg x 10, ip, one day apart) were observed by scanning electron microscopy. There was loss of contractivity, gradual disappearance of microtriches and progressive degeneration of tegument. Similar changes were noticed with mebendazole. The possession of better efficacy and higher safety range [Indian J Exp. Biol, 25 (1987) 871], suggests that the metabolite can be a potential anthelmintic for man and animals.