3 research outputs found

    α-Tocopheryl succinate stabilizes the structure of tumor vessels by inhibiting angiopoietin-2 expression

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    α-Tocopheryl succinate (TS) is a tocopherol derivative and has multifaceted anti-cancer effects; TS not only causes cancer cell-specific apoptosis but also inhibits tumor angiogenesis. Although TS has the potential to be used as a well-tolerated anti-angiogenic drug, it is still unclear which step of the angiogenic process is inhibited by TS. Here, we show that TS inhibits the expression of angiopoietin (Ang)-2, which induces destabilization of vascular structure in the initial steps of the angiogenic process. In mouse melanoma cells, TS treatment decreased mRNA and extracellular protein levels of Ang-2; however, the mRNA level of Ang-1, which stabilizes the vascular structure, remained unchanged. Furthermore, aorta ring and Matrigel plug angiogenesis assays indicated that the conditioned medium from TS-treated cells (CM-TS) inhibited neovascularization and blood leakage from the existing blood vessels, respectively. Following immunohistochemical staining of the vessels treated with CM-TS, imaging studies showed that the vascular endothelial cells were highly packed with pericytes. In conclusion, we found that TS inhibits Ang-2 expression and, consequently, stabilizes the vascular structure during the initial step of tumor angiogenesis

    The ethanol metabolite acetaldehyde inhibits the induction of long-term potentiation in the rat dentate gyrus in vivo

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    1. Ethanol has been reported to inhibit the induction of long-term potentiation (LTP) in the hippocampus. However, the correlation between the effects of ethanol in vivo and in vitro remained unclear. In addition, previous works have little considered the possibility that the effect of ethanol is mediated by its metabolites. To solve these problems, we investigated the effects of ethanol and acetaldehyde, the first metabolite in the metabolism of ethanol, on the induction of LTP at medial perforant path-granule cell synapses in the dentate gyrus of anaesthetized rats in vivo. 2. Oral administration of 1 g kg(−1) ethanol significantly inhibited the induction of LTP, confirming the effectiveness of ethanol in vivo. 3. A lower dose of ethanol (0.5 g kg(−1)) failed to inhibit the induction of LTP in intact rats, but significantly inhibited LTP in rats treated with disulfiram, an inhibitor of aldehyde dehydrogenase, demonstrating that LTP is inhibited by acetaldehyde accumulation following ethanol administration. 4. Intravenous injection of acetaldehyde (0.06 g kg(−1)) significantly inhibited the induction of LTP. 5. The inhibitory effect of acetaldehyde on LTP induction was also observed when it was injected into the cerebroventricules, suggesting that acetaldehyde has a direct effect on the brain. The intracerebroventricular dose of acetaldehyde effective in inhibiting LTP induction (0.1–0.15 mg brain(−1)) was approximately 10 fold lower than that of ethanol (1.0–1.5 mg brain(−1)). 6. It is possible that acetaldehyde is partly responsible for memory impairments induced by ethanol intoxication

    Combined Pre-Supernova Alert System with Kamland and Super-Kamiokande

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    International audiencePreceding a core-collapse supernova, various processes produce an increasing amount of neutrinos of all flavors characterized by mounting energies from the interior of massive stars. Among them, the electron antineutrinos are potentially detectable by terrestrial neutrino experiments such as KamLAND and Super-Kamiokande via inverse beta decay interactions. Once these pre-supernova neutrinos are observed, an early warning of the upcoming core-collapse supernova can be provided. In light of this, KamLAND and Super-Kamiokande have been monitoring pre-supernova neutrinos since 2015 and 2021, respectively. Recently, we performed a joint study between KamLAND and Super-Kamiokande on pre-supernova neutrino detection. A pre-supernova alert system combining the KamLAND detector and the Super-Kamiokande detector is developed and put into operation, which can provide a supernova alert to the astrophysics community. Fully leveraging the complementary properties of these two detectors, the combined alert is expected to resolve a pre-supernova neutrino signal from a 15 M⊙_{\odot} star within 510 pc of the Earth, at a significance level corresponding to a false alarm rate of no more than 1 per century. For a Betelgeuse-like model with optimistic parameters, it can provide early warnings up to 12 hours in advance
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