Publications by authors named "Naoto Oka"

Introduction: Since the first confirmed case of coronavirus disease 2019 (COVID-19) in China, COVID-19 continues to be a global threat and exerts a significant impact on medical practices. This study aims to investigate the impact of the COVID-19 pandemic on medical practices in Awaji Island, a remote island in Japan.

Methods: First, we conducted a survey on the epidemiological characteristics of COVID-19 on Awaji Island before and during the pandemic.

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NK cells, which are composed of phenotypically and functionally heterogeneous subpopulations, play critical roles in immunity against cancer. The mechanism of generation of distinct subsets such as the effector and regulatory subtypes is unclear. Here, we show that this process comprises several steps, including generation of proliferating, highly cytotoxic cells activated by IL-15/IL-18 and differentiation into distinct cell populations induced with IL-12.

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Combined stimulation by IL-2 and IL-18 effectively promotes proliferation of NK cells, whereas singular stimulation does not. In this study, synergistic effects of these cytokines on NK cells proliferation was analyzed, focusing on the roles of IL-18. In splenic resting NK cells from IL-18KO mice, IL-18 rapidly activated NF-κB independently of IL-2, and activated or up-regulated various molecules downstream of PI3K/AKT and mTOR, including S6, Bcl-XL, ATG5, and LC3II, accompanying increases in cell growth and survival.

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