ヘモグロビンと共存する還元型ニコチンアミドアデニンジヌクレオチドの隠れた抗酸化機能

Ferrous oxyhemoglobin (HbO2) in red blood cells (RBCs) invariably and slowly autoxidizes to form ferric methemoglobin (metHb). However, the level of metHb is always maintained below 0.5% by intracellular metHb reduction of enzymatic systems with coenzymes, such as reduced nicotinamide adenine dinucleotide (NADH), and by superoxide dismutase (SOD) and catalase (CAT), which eliminate reactive oxygen species. Unquestionably, NADH cannot reduce metHb without the corresponding enzymatic system. Our study, however, demonstrated that a high concentration of NADH (100-fold of normal level, equimolar to HbO2) retarded autoxidation of HbO2 in a highly purified Hb solution with no enzymatic system. Furthermore, an inhibitory effect of NADH on metHb formation was observed with additions of oxidants such as H2O2, NO, and NaNO2. Our mechanism assessment elucidated extremely high pseudo-CAT and pseudo-SOD activities of NADH with coexistence of HbO2, and reactivity of NADH with NO. We prepared a model of RBCs (Hb-vesicles, Hb-V) encapsulating purified HbO2 solution and NADH, but no enzymatic system within liposome. We confirmed the inhibitory effect of NADH on both autoxidation and oxidant-induced metHb formation. In addition, an intravenous administration of these Hb-Vs to rats caused significant retardation of metHb formation by approximately 50% compared to the case without NADH coencapsulation. Based on these results, we elucidated a new role of NADH, that is, antioxidative effect via interaction with Hb, in addition to its classical role as a coenzyme.博士（医学）・甲第687号・平成30年9月26日This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS chemical biology, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://dx.doi.org/ 10.1021/acschembio.7b0017

Ring-Opening Polymerization of Hemoglobin.

Hemoglobin (Hb), an oxygen-carrying protein, has an α₂β₂ tetrameric structure that dissociates reversibly into two αβ dimers (α₂β₂ ⇄ 2αβ). We synthesized a cyclic Hb-ring monomer with two β subunits bound through a 10 kDa polyethylene glycol (PEG) chain. The monomer induced ring-opening polymerization to produce a supramolecular polymer via intersubunit interaction of αβ dimers of an Hb molecule at the PEG terminals. Both the ring-closed monomer and the ring-opened supramolecular polymer were then fixed covalently by intramolecular cross-linking of two β subunits. Quantification of fixed products at various monomer concentrations revealed the equilibrium constant (K), a ratio of propagation and depropagation rate constants, as 5.68 mM⁻¹. The average degree of polymerization (DP) increased proportionally, concomitantly with the initial monomer concentration. Hb polymer with DP = 13.2 (Mn = ca.1 MDa) was obtained by cross-linking at 2.33 mM. Our novel strategy of ring-opening polymerization of Hb will eventually realize a highly aligned and efficiently polymerized Hb for creating artificial oxygen carriers for a clinical use.This document is the Accepted Manuscript version of a Published Work that appeared in final form in Biomacromolecules, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.biomac.8b01789

ヘモグロビン小胞体は無呼吸ラットにおいて循環虚脱までの時間を延長させる

BACKGROUND: Hemoglobin vesicles (HbV) are hemoglobin-based oxygen carriers manufactured by liposome encapsulation of hemoglobin molecules. We hypothesised that the infusion of oxygenated HbV could prolong the time to circulatory collapse during apnea in rats. METHODS: Twenty-four Sprague-Dawley rats were randomly divided into four groups (Air, Oxy, NS and HbV). The rats were anaesthetized with isoflurane and the trachea was intubated using 14-gauge intravenous catheters. Rats in the Air group were mechanically ventilated with 1.5% isoflurane in room air, and those in other groups received 1.5% isoflurane in 100% oxygen. Mechanical ventilation was withdrawn 1 min after the administration of rocuronium bromide to induce apnea. After 30 s, 6 mL saline and HbV boluses were infused at a rate of 0.1 mL/s in the NS and HbV groups, respectively. Circulatory collapse was defined as a pulse pressure < 20 mmHg and the time to reach this point (PP20) was compared between the groups. The results were analysed via a one-way analysis of variance and post-hoc Holm-Sidak test. RESULTS: PP20 times were 30.4 ± 4.2 s, 67.5 ± 9.7 s, 95 ± 17.3 s and 135 ± 38.2 s for the Air (ventilated in room air with no fluid bolus), Oxy (ventilated with 100% oxygen with no fluid bolus), NS (ventilated with 100% oxygen with a normal saline bolus), and HbV (ventilated in 100% oxygen with an HbV bolus) groups, respectively, and differed significantly between the four groups (P = 0.0001). The PP20 times in the HbV group were significantly greater than in the Air (P = 0.0001), Oxy (P = 0.007) and NS (P = 0.04) groups. CONCLUSION: Infusion of oxygenated HbV prolongs the time to circulatory collapse during apnea in rats.博士（医学）・甲第680号・平成30年3月15日© The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated

Exploring how plasma- and muscle-related parameters affect trout hemolysis as a route to prevent hemoglobin-mediated lipid oxidation of fish muscle

Hemoglobin (Hb) is a powerful promoter of lipid oxidation, particularly in muscle of small pelagic fish species and fish by-products, both having high Hb-levels and highly unsaturated lipids. As Hb is located within the red blood cells (RBCs) it is here hypothesized that the perishable polyunsaturated fatty acids (PUFAs) can be protected from oxidation by limiting hemolysis during early fish processing. Using a model system consisting of washed-resuspended trout (Oncorhynchus mykiss) RBCs (wr-RBCs), the aim of this study was to evaluate how RBC lysis under cold storage was affected by selected parameters linked to blood or muscle: bacterial growth, energy status, pH, RBC membrane lipid oxidation and colloidal osmotic pressure (COP). The results indicated that bacterial growth had a modest effect on hemolysis while pH-values typical for post mortem fish muscle (6.4–6.8), and absence of glucose or albumin stimulated hemolysis. The rapid hemolysis observed at pH 6.4–6.8 correlated with lipid oxidation of the RBC membrane, while the lower hemolysis at pH 7.2–8.0 occurred with low, or without any RBC membrane lipid oxidation. When hemin was added to the RBCs at pH 6.8 hemolysis was induced without parallel RBC membrane oxidation, pointing at Hb-autoxidation and hemin-release per se as important events triggering lysis in fish muscle. Altogether, the study provided valuable findings which ultimately can aid development of new tools to combat lipid oxidation in post mortem fish muscle by limiting hemolysis

1950～1970年代日本における性売買構造の展開

2021南山大学1950～1970年代日本における性売買構造の展開2016～2021年度科学研究費助成事業 (基盤研究 (C) (一般)) 研究成果報告

Relationship between Visual Acuity and Lifestyle: A Cross-Sectional Study in Japanese Children

Purpose: To evaluate poor visual acuity (PVA) prevalence and factors related to PVA, including parental myopia status and lifestyle, in primary school children. Methods: Of total 220 primary school children from grades 4–6 in Hiroshima, 184 (83.6%) were enrolled in the study. They were divided into non-PVA (both eyes’ acuities ≥ 1.0) and PVA (one or both eyes’ acuity < 1.0 and/or wearing spectacles) groups. Data on lifestyle activities were obtained using self-reported questionnaires regarding daily lifestyle, including the duration of watching TV, playing games, using a computer, studying, number of books read per month, and outdoor activities. Results: The total prevalence of PVA was 66.8%: 50.0% for grade 4, 71.4% for grade 5, and 74.6% for grade 6. In binary logistic regression models, children who had at least one parent with myopia showed greater PVA than those with parents without myopia (OR = 1.89; 95% CI, 1.14 to 3.15). In addition, weekend studying was significantly associated with PVA (OR = 1.48; 95% CI, 1.03 to 2.12), and the number of books read per month was associated with PVA (OR = 1.26, 95% CI, 1.05 to 1.51). Conclusions: This study confirmed a high PVA prevalence in primary school children, and that the rate of PVA increased with advancing grade. Parental myopia was associated with PVA, as were long studying time and a high number of books read per month