Japanese Journal of Veterinary Research;Volume 10, Number 3

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STUDIES ON ECHINOCOCCOSIS. XIII : OBSERVATIONS ON THE VESICULAR DEVELOPMENT OF THE SCOLEX OF E. MULTILOCULARIS IN VITRO

YAMASHITA, Jiro;OHBAYASHI, Masashi;SAKAMOTO, Tsukasa;ORIHARA, Miyoji

Permalink : http://hdl.handle.net/2115/1768
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Abstract

The vesicular development of the scolex of E. multilocularis was investigated in media which consisted essentially of 0.5% lactalbumin in HANKS' solution. The results obtained are as follows. 1. For the purpose of defining the relation between the vesicular development of the scolex and the composition of media, scolices were incubated in the media containing various percentages of additionals such as bovine serum, bovine bile and liver extract. It was clarified that bovine serum was a necessary element for survival of a scolex. On the other hand, bovine bile and liver extract accelerated the vesiculation of scolex, but these substances had a tendency to cause degeneration and rupture of the scolex. The proportion of vesiculated scolices was noted the highest in 0.5% lactalbumin HANKS' solution combined with 20% bovine serum and 10% liver extract, intermediate in 0.5% lactalbumin HANKS' solution with 20% serum and 0.5% bovine bile and lowest in 0.5% lactalbumin HANKS' solution with 20% serum. Degeneration and rupture of scolices increased in parallel with the above rate, but the percentage of scolices showing mobility decreased, inversely. 2. The process of scolex vesiculation was classified into three types. In the first type, the scolex itself vesiculated globularly while in the second, the cyst was formed from a vacuole formed at the anterior or posterior extremity of the scolex. The third type was one in which a combination of the above two types was noted. 3. In the process of scolex vesiculation, disappearance of parenchymal cells, metamorphosis of subcuticular cells and increase of calcareous corpuscles were recognized. The vesicle completed by the above process manifested enlargement and multilocular vesiculation. 4. Collections of germinal cells similar to the early stage of brood capsule were found in some cysts. 5. In the vesiculated scolex which showed deficient thickening of the cuticular layer in proportion to increase of its volume, rupture due to increase of inner pressure was recognized. On the contrary, in the cysts with remarkable thickening of the cuticular layer, the size was increased very slowly. 6. The vesiculated scolices, which were incubated together with HeLa cells, were embedded in the layer of HeLa cells. They continued gradual enlargement and multilocular vesiculation.

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