間 祐太朗 (ハマザ ユウタロウ)

Hazama Yutaro

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  • Effects of self-locomotion on the activity of place cells in the hippocampus of a freely behaving monkey.

    Yutaro Hazama, Ryoi Tamura

    Neuroscience Letters ( Elsevier )  701   32 - 37   2019年05月  [査読有り]

    共著

    The activity of hippocampal cell assemblies is considered to function as the neural substrate for a cognitive map in various animal species. The firing rate of hippocampal place cells increases when an individual animal reaches a specific location in an environment. Although cumulative views on place cells have been revealed by studies using rodents under free-behavior conditions, few studies have addressed the spatial representation provided by hippocampal neurons in primates. Moreover, although previous work in rats has demonstrated the importance of locomotion velocity and direction in the spatially selective discharge of hippocampal neurons, it remains unknown whether a corresponding phenomenon exists in the primate hippocampus. In the present study, we recorded the activity and investigated the spatial representation of the hippocampal neurons in a freely behaving monkey performing a shuttle-movement task. We observed increased activity in a subset of hippocampal neurons (place cells) when the monkey crossed a particular location. Many of the monkey place cells exhibited sensitivity to locomotion velocity rather than to locomotion direction. These results suggest the existence of primate hippocampal place cells comparable to those in rodents, with the exception that, in primates, velocity information has a stronger impact on place cell activity than directional information.

    DOI PubMed

  • Preclinical study of tacrolimus ointment for prevention of its systemic absorption in atopic dermatitis model mice according to their skin conditions

    Yutaro Hazama, Wataru Uchida, Toshihisa Maekawa,Ryotaro Miki, Shinji Oshima, Yuya Egawa, Osamu Hosoya, Toshinobu Seki

    Japanese Journal of Pharmaceutical Health Care and Sciences ( Japanese Society of Pharmaceutical Health Care and Sciences )  43 ( 9 ) 477 - 491   2017年09月  [査読有り]

    共著

    Tacrolimus (TL) is used topically for atopic dermatitis (AD) treatment. In AD, the skin shows various physiological alterations across individuals, body sites, and time-courses. Our previous study using rats showed that alterations in the skin barrier function and skin blood flow affected systemic absorption of topically applied TL. In this study, we performed an in vivo skin absorption study using NC/Nga mice repeatedly administered Dermatophagoides farinae extract as an AD animal model to assess skin barrier function and skin blood flow. We used three types of TL ointment: or iginal TL ointment (Protopic® 0.1% ointment) and liquid paraffin-diluted TL ointment with or without adrenaline (0.5w /w%) to suppress systemic absorption of TL. Skin barrier function correlated positively with the systemic absorption of TL in AD skin as well as in tape-stripped rat skin, and dilution of TL ointment suppressed TL absorption and showed high skin TL retention. Although skin blood flow affected TL absorption as the skin barrier was disrupted, the distinct relationship among skin blood flow, TL absorption, and the effect of combined-use of adrenaline was unclear. The relationship between blood and skin disposition of TL was biphasic—the ratio of blood to skin disposition increased rapidly at an inflection point. These results demonstrate that the dilution of TL ointment is useful for increasing treatment safety while retaining efficacy. The observed relationship between TL behavior and skin barrier function in AD model mice may also occur in AD patients and needs to be confirmed in further studies.

    JURA Repository DOI

  • Effect of physiological changes in the skin on systemic absorption of tacrolimus following topical application in rats

    Yutaro Hazama, Toshihisa Maekawa, Ryotaro Miki, Shinji Oshima, Yuya Egawa, Kazuhiro Morimoto, Toshinobu Seki

    Biological and Pharmaceutical Bulletin ( The Pharmaceutical Society of Japan )  39 ( 3 ) 343 - 352   2016年03月  [査読有り]

    共著

    Tacrolimus (TL) ointment is a topical treatment for atopic dermatitis, a disease that exhibits various skin conditions. The effect of skin pathologies on the systemic absorption of TL and related side effects remains unknown. This study aimed to investigate factors affecting the cutaneous absorption of TL. We prepared various skin models in hairless rats by tape stripping, injection of prophlogistic material solution (PMS), and continuous subcutaneous adrenaline (Adr) infusion. In vivo absorption studies were conducted, with measurements of transepidermal water loss (TEWL) and skin blood flow as physiological parameters. Very little TL absorption was observed through intact skin. Greater TL absorption was noted in skins with high TEWL values and fully stripped skin with PMS injections. In contrast, Adr infusion, which reduced skin blood flow, resulted in decreased TL absorption through fully stripped skin. Combined use of TL and Adr on skin with PMS injections resulted in suppression of TL absorption. Our results revealed that TL absorption following topical application is affected by alterations in the skin barrier, blood flow, and vascular permeability. We propose an administration plan for TL in a flowchart as a means of preventing systemic side effects.

    JURA Repository DOI PubMed

  • フェンタニル貼付剤の粘着性に関する検討―貼付試験と粘着性による評価―

    大島 新司, 間 祐太朗, 細谷 治, 長島 健悟, 田中 享, 佐野 元彦, 太田 昌一郎, 安野 伸浩, 從二 和彦

    日本緩和医療薬学雑誌 ( 日本緩和医療薬学会 )  5 ( 1 ) 7 - 13   2012年03月  [査読有り]

    共著

    フェンタニル貼付剤は、その製剤学的特性から、経口摂取困難な患者や在宅緩和ケア領域で、持続痛をコントロールするのに非常に適した製剤である。貼付期間中の剥れや痒みは、除痛効果の低下や貼付部位の不快感を誘発する。しかしながら、それら使用感に関する報告はあまり多く見受けられない。今回われわれは、3種類のフェンタニル貼付剤について、使用感(貼付時の感覚)調査および粘着性に関する研究を行った。フェントステープは、その高い粘着性のため剥離後の皮膚刺激感を与えることが示唆された。一方、デュロテップMTパッチおよびワンデュロパッチの部分的な剥離や脱落は、それらの粘着性の低さが要因と考えられた。がん対策基本法施行以来、緩和ケアにおけるがん疼痛治療期間が長期に及ぶ傾向にあり、本研究結果は、患者のアドヒアランスの向上や適切な薬物療法の維持のために重要な情報を与えるものと考える。

    JURA Repository