In vivo effect of benzothiazole and amoscanate derivatives on the fine structure of adult Brugia spp. and Litomosoides carinii.

Alterations in the fine structures of female Brugia spp. and Litomosoides carinii were investigated after in vivo treatment with curative doses of 4 compounds: CGP 20376 [2-tert-butyl-benzothiazole-5-methoxy-6-dithiocarbamic-S-(2- carboxyethyl)-ester], CGP 21833 (2-tert-butyl-benzothiazole-5-methyl-6- N-methylamino-piperazinylthiocarbonylamide), CGP 6140 [4-Nitro-4'-(N-methyl-piperazinylthiocarbonylamido)-diphenylamine] and amoscanate (4-isothiocyanato-4'-nitrodiphenylamine). All compounds caused early alterations in the somatic muscle cells. These alterations usually appeared within 24 h after treatment; they occurred later only after treatment of L. carinii with amoscanate. In Brugia spp., swelling of the muscle cells occurred in which the glycogen deposits considerably increased in size. The electron density of the cytoplasm surrounding the myofilaments in the fibrillar portion of the muscle cells increased, and light zones appeared between the fibrils. The muscle cell mitochondria swelled, particularly their inner matrix, which became more electron-lucent, with some dense spots. In L. carinii the muscle cells were not increased in size, but their mitochondria were considerably swollen before disintegration; this was followed by disintegration of the myofilaments and vacuolization of the cytoplasm. Vacuolization before mitochondrial swelling was observed only after treatment with CGP 6140. Other tissues of this species were not altered before the 2nd day after treatment. In Brugia spp., electron-lucent appeared in the hypodermis either simultaneously with the alterations in the muscle cells or a few hours later. At 24 h after treatment with amoscanate, blebs were formed on the luminal side of the intestinal membrane.