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Dive into the research topics where Ryosuke Kurokawa is active.

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Featured researches published by Ryosuke Kurokawa.


Medical gas research | 2012

Consumption of water containing a high concentration of molecular hydrogen reduces oxidative stress and disease activity in patients with rheumatoid arthritis: an open-label pilot study

Toru Ishibashi; Bunpei Sato; Mariko Rikitake; Tomoki Seo; Ryosuke Kurokawa; Yuichi Hara; Yuji Naritomi; Hiroshi Hara; Tetsuhiko Nagao

BackgroundRheumatoid arthritis (RA) is a chronic inflammatory disease characterized by the destruction of bone and cartilage. Although its etiology is unknown, the hydroxyl radical has been suggested to be involved in the pathogenesis of RA. Recently, molecular hydrogen (H2) was demonstrated to be a selective scavenger for the hydroxyl radical. Also, the method to prepare water containing extremely high concentration of H2 has been developed. We hypothesized that H2 in the water could complement conventional therapy by reducing the oxidative stress in RA.MethodsTwenty patients with rheumatoid arthritis (RA) drank 530 ml of water containing 4 to 5 ppm molecular hydrogen (high H2 water) every day for 4 weeks. After a 4-week wash-out period, the patients drank the high H2 water for another 4 weeks. Urinary 8-hydroxydeoxyguanine (8-OHdG) and disease activity (DAS28, using C-reactive protein [CRP] levels) was estimated at the end of each 4-week period.ResultsDrinking high H2 water seems to raise the concentration of H2 more than the H2 saturated (1.6 ppm) water in vivo. Urinary 8-OHdG was significantly reduced by 14.3% (p < 0.01) on average. DAS28 also decreased from 3.83 to 3.02 (p < 0.01) during the same period. After the wash-out period, both the urinary 8-OHdG and the mean DAS28 decreased, compared to the end of the drinking period. During the second drinking period, the mean DAS28 was reduced from 2.83 to 2.26 (p < 0.01). Urinary 8-OHdG was not further reduced but remained below the baseline value. All the 5 patients with early RA (duration < 12 months) who did not show antibodies against cyclic citrullinated peptides (ACPAs) achieved remission, and 4 of them became symptom-free at the end of the study.ConclusionsThe results suggest that the hydroxyl radical scavenger H2 effectively reduces oxidative stress in patients with this condition. The symptoms of RA were significantly improved with high H2 water.


Medical gas research | 2012

A convenient method for determining the concentration of hydrogen in water: use of methylene blue with colloidal platinum

Tomoki Seo; Ryosuke Kurokawa; Bunpei Sato

A simple titration (oxidimetry) method using a methylene blue-platinum colloid reagent is effective in determining the concentration of hydrogen gas in an aqueous solution. The method performs as effectively as the more complex and expensive electrochemical method.


Scientific Reports | 2015

Estimation of the hydrogen concentration in rat tissue using an airtight tube following the administration of hydrogen via various routes

Chi Liu; Ryosuke Kurokawa; Masayuki Fujino; Shinichi Hirano; Bunpei Sato; Xiao-Kang Li

Hydrogen exerts beneficial effects in disease animal models of ischemia-reperfusion injury as well as inflammatory and neurological disease. Additionally, molecular hydrogen is useful for various novel medical and therapeutic applications in the clinical setting. In the present study, the hydrogen concentration in rat blood and tissue was estimated. Wistar rats were orally administered hydrogen super-rich water (HSRW), intraperitoneal and intravenous administration of hydrogen super-rich saline (HSRS), and inhalation of hydrogen gas. A new method for determining the hydrogen concentration was then applied using high-quality sensor gas chromatography, after which the specimen was prepared via tissue homogenization in airtight tubes. This method allowed for the sensitive and stable determination of the hydrogen concentration. The hydrogen concentration reached a peak at 5 minutes after oral and intraperitoneal administration, compared to 1 minute after intravenous administration. Following inhalation of hydrogen gas, the hydrogen concentration was found to be significantly increased at 30 minutes and maintained the same level thereafter. These results demonstrate that accurately determining the hydrogen concentration in rat blood and organ tissue is very useful and important for the application of various novel medical and therapeutic therapies using molecular hydrogen.


Medical gas research | 2015

Convenient methods for ingestion of molecular hydrogen: drinking, injection, and inhalation

Ryosuke Kurokawa; Tomoki Seo; Bunpei Sato; Shinichi Hirano; Fumitake Sato

Molecular hydrogen (H2) is clinically administered; however, in some hospitals, H2 is given to patients without consideration of its safe use. In the present study, we prepared convenient and safe devices for the drinking of super-saturated H2 water, for intravenous drip infusion of H2-rich saline, and for the inhalation of H2 gas. In order to provide useful information for researchers using these devices, the changes in H2 concentration were studied. Our experimental results should contribute to the advance of non-clinical and clinical research in H2 medicine.


The Scientific World Journal | 2014

Hydrogen Supplementation of Preservation Solution Improves Viability of Osteochondral Grafts

Takuya Yamada; Kentaro Uchida; Kenji Onuma; Jun Kuzuno; Masanobu Ujihira; Gen Inoue; Bunpei Sato; Ryosuke Kurokawa; Rina Sakai; Masashi Takaso

Allogenic osteochondral tissue (OCT) is used for the treatment of large cartilage defects. Typically, OCTs collected during the disease-screening period are preserved at 4°C; however, the gradual reduction in cell viability during cold preservation adversely affects transplantation outcomes. Therefore, improved storage methods that maintain the cell viability of OCTs are needed to increase the availability of high-quality OCTs and improve treatment outcomes. Here, we evaluated whether long-term hydrogen delivery to preservation solution improved the viability of rat OCTs during cold preservation. Hydrogen-supplemented Dulbeccos Modified Eagles Medium (DMEM) and University of Wisconsin (UW) solution both significantly improved the cell viability of OCTs during preservation at 4°C for 21 days compared to nonsupplemented media. However, the long-term cold preservation of OCTs in DMEM containing hydrogen was associated with the most optimal maintenance of chondrocytes with respect to viability and morphology. Our findings demonstrate that OCTs preserved in DMEM supplemented with hydrogen are a promising material for the repair of large cartilage defects in the clinical setting.


Scientific Reports | 2018

Molecular hydrogen protects against ischemia-reperfusion injury in a mouse fatty liver model via regulating HO-1 and Sirt1 expression

Shaowei Li; Masayuki Fujino; Naotsugu Ichimaru; Ryosuke Kurokawa; Shinichi Hirano; Lisha Mou; Shiro Takahara; Terumi Takahara; Xiao-Kang Li

Fatty liver has lower tolerance against ischemia-reperfusion (I/R) injury in liver operations, including liver transplantation. Seeking to ameliorate liver injury following I/R in fatty liver, we examined the protective effect of hydrogen (H2) saline on I/R liver injury in a methionine and choline-deficient plus high fat (MCDHF) diet-induced fatty liver mouse model. Saline containing 7 ppm H2 was administrated during the process of I/R. Livers were obtained and analyzed. Primary hepatocytes and Kupffer cells (KCs) were obtained from fatty liver and subjected to hypoxia/reoxygenation. Apoptosis-related proteins and components of the signaling pathway were analyzed after treatment with hydrogen gas. The MCDHF I/R group showed higher levels of AST and ALT in serum, TUNEL-positive apoptotic cells, F4/80 immunopositive cells, mRNA levels of inflammatory cytokines, constituents of the signaling pathway, pro-apoptotic molecules in liver, and KCs and/or primary hepatocytes, compared to the control group. In contrast, H2 treatment significantly suppressed the signs of I/R injury in fatty liver. Moreover, the expression of Bcl-2, HO-1, and Sirt1 in liver, KCs, and hepatocytes by hydrogen gas were increased, whereas caspase activation, Bax, and acetylation of p53 were suppressed by hydrogen gas. These results demonstrated that H2 treatment ameliorated I/R liver injury in a fatty liver model by reducing hepatocyte apoptosis, inhibiting macrophage activation and inflammatory cytokines, and inducing HO-1 and Sirt1 expression. Taken togather, treatment with H2 saline may have a protective effect and safe therapeutic activity during I/R events, such as in liver transplantation with fatty liver.


Archive | 2012

Selective hydrogen adding equipment for living organism applicable fluid

Fumitake Satoh; Tomoki Seo; Ryosuke Kurokawa; Bunpei Satoh; Tatsuya Naito; Tomoyuki Yanagihara; Yohei Satoh; Yoko Satoh


Archive | 2011

Instrument for selective hydrogenation of liquid for biological use

Fumitake Satoh; Tomoki Seo; Ryosuke Kurokawa; Bunpei Satoh; Tatsuya Naito


Archive | 2011

Device for selectively hydrogenating biocompatible solution

Fumitake Satoh; Tomoki Seo; Ryosuke Kurokawa; Bunpei Satoh; Tatsuya Naito; Tomoyuki Yanagihara; Yohei Satoh; Yoko Satoh


Archive | 2012

Hydrogen adding equipment for living organism applicable fluid

Fumitake Satoh; Tomoki Seo; Ryosuke Kurokawa; Bunpei Satoh

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Masayuki Fujino

National Institutes of Health

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