Publications by authors named "Syun Tokita"

Spermatogonial stem cells (SSCs) colonize nonablated recipient testes. Autotransplantation of SSCs is expected to restore fertility in boys who become infertile due to cancer therapy. However, since the number of SSCs recovered from testis biopsies is small, increasing SSC number is a prerequisite.

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We investigated potential germline-specific radiosensitive biomarkers in the testes of large Japanese field mice (Apodemus speciosus) exposed to low-dose-rate (LDR) radiation after the Fukushima accident. Fukushima wild mice testes were analysed via RNA-sequencing to identify genes differentially expressed in the breeding and non-breeding seasons when compared to controls. Results revealed significant changes during the breeding season, with Lsp1 showing a considerable upregulation, while Ptprk and Tspear exhibited significant reductions.

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Because of the advent of genome-editing technology, gene knockout (KO) hamsters have become attractive research models for diverse diseases in humans. This study established a new KO model of diabetes by disrupting the insulin receptor substrate-2 (Irs2) gene in the golden (Syrian) hamster. Homozygous KO animals were born alive but with delayed postnatal growth until adulthood.

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Article Synopsis
  • The Fukushima Daiichi Nuclear Power Plant accident has prompted research into the effects of chronic low-dose-rate radiation exposure on biological systems, particularly its impact on the reproductive system and potential infertility.
  • A study was conducted on the testis ultrastructure of wild large Japanese field mice from contaminated areas with varying radiation levels, revealing preserved seminiferous tubules similar to unexposed controls, but with some structural changes.
  • Findings indicated increased lipid droplet clusters in spermatogenic cells and changes related to spermatogenesis, suggesting that while there were ultrastructural modifications, the overall process of spermatogenesis remained normal in mice exposed to low-dose radiation.
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Wild large Japanese field mice () responses to cyclic seasonal changes are associated with physiological and behavioral changes. However, the detailed regulation of oogenesis in the ovary during the seasonal reproductive cycle in wild large Japanese field mice has not been studied. We assessed the dynamics and changes in ovarian morphology and hormone concentrations associated with reproductive seasonality throughout the year.

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