The modal number of chromosomes in Eptatretus burgeri was 36 in 297 (81.8%) of 363 somatic cells, 52 in 13 (30.2%) of 43 spermatogonia, and 25 (46.8%) or 26 (40.3%) in 162 of 186 first spermatocytes. The relative amount of DNA in a somatic cell to that in a spermatogonium averaged 79.2%. C-band-positive chromatin was observed along almost the entire length of the associated dumbbell-shaped bivalents and part of two other bivalents in the metaphases of first spermatocytes, but was rarely observed in somatic cells. These results indicate that, in E. burgeri, chromosome elimination takes place during the early stages of cleavage, except for the ancestral germ-line cells.

This new cell fusion method is characterized by production of hybridomas of target cells, lower cell toxicity, and a high rate of hybrid production.

The influence of selenium dioxide on the in vitro and in vivo growth of transplantable B16 melanoma was studied. In the in vivo study, melanoma tissues showed a decrease in development of tumor growth and a tendency toward higher levels of free radical signal (ESR). Cultured B16 melanoma cells revealed a marked disturbance of cell growth especially in the solution with a high dose of selenium. These results may indicate that selenium has an antitumorigenic effect on B16 melanoma cells.

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