Education 【 display / non-display 】

Education 【 display / non-display 】

• 2018

  -

  2021

  Hokkaido University   Graduate School of Health Sciences  

• 2016

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  2018

  Hokkaido University   Graduate School of Health Sciences  

• 2011

  -

  2016

  Hokkaido University   School of Medicine   Department of Health Sciences  

Degree 【 display / non-display 】

Degree 【 display / non-display 】

• 2021.03   北海道大学   博士（保健科学）

Research Experience 【 display / non-display 】

Research Experience 【 display / non-display 】

• 2024.11

  -

  Now

  Asahikawa Medical University   Center for Medical Education and Regional Symbiosis   Lecturer

• 2022.04

  -

  2024.10

  Sapporo Medical University   Scholarly Communication Center   Assistant Professor

• 2021.04

  -

  2022.03

  Hokkaido University   Faculty of Health Sciences   特任助教

Affiliation 【 display / non-display 】

Affiliation 【 display / non-display 】

• Asahikawa Medical University   Center for Medical Education and Regional Symbiosis   Lecturer  

Papers 【 display / non-display 】

Papers 【 display / non-display 】

• Potential crowdedness of mechanical thrombectomy and cerebral infarction mortality in Japan: Application of inverted two-step floating catchment area method.

  Kazuki Ohashi, Kensuke Fujiwara, Toshiya Osanai, Takumi Tanikawa, Kyohei Bando, Shojiro Yamasaki, Tomohiro Aoki, Songzi Gu, Katsuhiko Ogasawara

  Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association   31 ( 9 ) 106625 - 106625  2022.09  [International journal]

  　View Summary

  OBJECTIVES: This study aimed to evaluate a stroke medical delivery system based on population coverage and the potential crowdedness index (PCI) of mechanical thrombectomy and investigate the relationship between PCI and cerebral infarction mortality in Japan. MATERIALS AND METHODS: This cross-sectional study defined 662 facilities and 1605 neurointerventionalists as supply, population aged 55 years or older as demand, and set the reachable area for demand as 120 min in driving time. Multiple regression analysis adjusted for spatial autocorrelation was used to examine the relationship between PCI and cerebral infarction mortality. RESULTS: In the 2020 data, 99% of the population aged 55 years or older had access to mechanical thrombectomy (≤120 min), and the PCI ranged from 5876 to 129838, with a median of 30426. From 2020 to 2035, the PCI is estimated to increase (30426 to 32510), decreasing after 2035 (32510 to 29469). The PCI distribution exhibited geographical heterogeneity. High PCI values emerged in eastern Japan. According to regression analysis, the increase in PCI by 1% led to an increase of 0.13% in standardized mortality ratio of cerebral infarction in men. However, PCI did not significantly correlate with cerebral infarction mortality in women. CONCLUSIONS: PCI for hospitals based on supply and demand was geographically heterogeneous in Japan. Optimization of PCI contributes equalization of mechanical thrombectomy provision system and may improve cerebral infarction mortality.

  DOI PubMed

• The impact of elevated blood lead levels in children on maternal health-related quality of life

  Hokuto Nakata, Harukazu Tohyama, Wakako Fujita, Shouta M.M. Nakayama, Mayumi Ishizuka, John Yabe, Nosiku S. Munyinda, Doreen Sakala, Kennedy Choongo, Shojiro Yamasaki, Natsumi Nagai, Takahiko Yoshida, Takeshi Saito

  Chemosphere   279  2021.09  [Refereed]  [International journal]  [International coauthorship]

  　View Summary

  Kabwe is a mining town in Zambia that has been ranked among “the ten most polluted places in the world” with previous findings of serious lead (Pb) pollution. In this study, we aim to examine the impact of childhood Pb poisoning on the health-related quality of life (HRQoL) of mothers in Kabwe. The HRQoL was assessed using the Short-Form 36 survey for 404 mothers coming from residences in 40 randomly selected standard enumeration areas (SEAs). Blood lead levels (BLLs) of the household members including the mothers themselves were measured. We found a significant positive correlation between the BLLs of the mothers and their children (R = 0.6385, p < 0.0001), while the BLLs of preschool-aged and school-aged children were significantly higher than those of their mothers and fathers. Using the data sets containing the BLLs of the household members, the age of the mothers, the household income, and the household SEA, we performed stepwise multiple linear regression analyses. The results showed significant negative associations between the representative BLL of household children and the BLL of preschool-aged children with the vitality and mental health scores of their mothers. Additionally, the BLL of school-aged children was only significantly associated with the mental health score of their mothers. By contrast, there was a significant negative association between the BLLs of the mothers with the social role functioning score. This suggests that elevated BLLs in children have a negative impact on the mental health conditions of their mothers regardless of the mothers’ BLL.

  DOI PubMed

• Amelioration of metal-induced cellular stress by α-lipoic acid and dihydrolipoic acid through antioxidative effects in pc12 cells and caco-2 cells

  Kaniz Fatima Binte Hossain, Mahmuda Akter, Md Mostafizur Rahman, Md Tajuddin Sikder, Md Shiblur Rahaman, Shojiro Yamasaki, Goh Kimura, Tomomi Tomihara, Masaaki Kurasaki, Takeshi Saito

  International Journal of Environmental Research and Public Health   18 ( 4 ) 1 - 15  2021.02  [Refereed]  [International journal]  [International coauthorship]

  　View Summary

  α-Lipoic acid (ALA) and its reduced form dihydrolipoic acid (DHLA) are endogenous dithiol compounds with significant antioxidant properties, both of which have the potential to detoxify cells. In this study, ALA (250 µM) and DHLA (50 µM) were applied to reduce metal (As, Cd, and Pb)-induced toxicity in PC12 and Caco-2 cells as simultaneous exposure. Both significantly decreased Cd (5 µM)-, As (5 µM)-, and Pb (5 µM)-induced cell death. Subsequently, both ALA and DHLA restored cell membrane integrity and intracellular glutathione (GSH) levels, which were affected by metal-induced toxicity. In addition, DHLA protected PC12 cells from metal-induced DNA damage upon co-exposure to metals. Furthermore, ALA and DHLA upregulated the expression of survival-related proteins mTOR (mammalian target of rapamycin), Akt (protein kinase B), and Nrf2 (nuclear factor erythroid 2-related factor 2) in PC12 cells, which were previously downregulated by metal exposure. In contrast, in Caco-2 cells, upon co-exposure to metals and ALA, Nrf2 was upregulated and cleaved PARP-1 (poly (ADP-ribose) polymerase-1) was downregulated. These findings suggest that ALA and DHLA can counterbalance the toxic effects of metals. The protection of ALA or DHLA against metal toxicity may be largely due to an enhancement of antioxidant defense along with reduced glutathione level, which ultimately reduces the cellular oxidative stress.

  DOI PubMed

• Effects of curcumin, D-pinitol alone or in combination in cytotoxicity induced by arsenic in PC12 cells

  Md Shiblur Rahaman, Shojiro Yamasaki, Kaniz Fatima Binte Hossain, Toshiyuki Hosokawa, Takeshi Saito, Masaaki Kurasaki

  Food and Chemical Toxicology   144  2020.10  [Refereed]  [International journal]

  　View Summary

  Arsenic is a well-known potent toxicant affecting people by causing various human diseases. Long-term exposure to arsenic has strong adverse health effects on liver and kidney disorders, and various forms of cancer. Contrarily, curcumin and D-pinitol are bioactive dietary compounds that have antioxidant properties. Both are used to treat a broad variety of human diseases. Thus, we hypothesized that both may have synergistic effects against arsenic-induced toxicity in PC12 cells. Cells were pretreated with curcumin (1, 2.5, 5 and 10 μM), D-pinitol (1, 2.5, 5 and 10 μM) alone or in combination, then exposed to sodium arsenite (10 μM). The final concentration of curcumin 2.5 μM and D-pinitol 5 μM was selected for combination treatment based on their highest protection at lowest concentration against arsenic toxicity. Results demonstrated that pretreatment of curcumin and D-pinitol and their combined treatment with arsenic rescued PC12 cells. Western blot analysis results showed that pretreatment of curcumin and D-pinitol and their combined treatment with arsenic significantly inhibited arsenic-induced cell death through up-regulation of pro-survival proteins and down-regulation of cell death-related proteins, although these protein expressions were negatively regulated by arsenic. Furthermore, the effect of combined treatment with curcumin and D-pinitol was stronger than individual treatment.

  DOI PubMed

• Maternal green tea extract intake during lactation attenuates hepatic lipid accumulation in adult male rats exposed to a continuous high-fat diet from the foetal period

  Shojiro Yamasaki, Goh Kimura, Kazunari Koizumi, Ning Dai, Rahel Mesfin Ketema, Tomomi Tomihara, Yukako Ueno, Yuki Ohno, Shin Sato, Masaaki Kurasaki, Toshiyuki Hosokawa, Takeshi Saito

  Food and Nutrition Research   64   1 - 10  2020  [Refereed]  [International journal]

  Authorship：   Lead author

  　View Summary

  Background: Maternal lipid intake in the early postnatal period has a long-term effect on the possibility of fatty liver formation in children; besides, the importance of lipid consumption during lactation for children’s health has been suggested. Green tea extract (GTE) contains abundant catechins, and it has been reported to improve lipid metabolism and prevent fatty liver. Objective: The aim of this study was to examine the effects of maternal GTE intake during lactation on hepatic lipid accumulation in adult male rats exposed to a continuous high-fat (HF) diet from the foetal period. Methods: Pregnant Wistar rats received diets containing 13% (control-fat, CON) or 45% (high-fat, HF) fat. CON-fed mothers received the same diet during lactation, whereas HF-fed mothers received either HF diet alone or HF diet supplemented with 0.24% GTE. At weaning, male offspring were divided into three groups, i.e. CON/CON/CON, HF/HF/HF (HF-offspring) or HF/HF+GTE/HF (GTE-offspring), and were fed until 51 weeks. Results: A significant hepatic triglyceride (Tg) accumulation was observed in the HF-offspring when compared with the other offspring. This is presumed to be caused by the promotion of Tg synthesis derived from exogenous fatty acid due to a significant increase in diacylglycerol O-acyltransferase 1 and a decrease in Tg expenditure caused by decreasing microsomal triglyceride transfer protein (MTTP) and long-chain acyl-CoA dehydrogenase. On the other hand, attenuated hepatic Tg accumulation was observed in the GTE-offspring. The levels of the hepatic lipid metabolism-related enzymes were improved to the same level as the CON-offspring, and particularly, MTTP was significantly increased as compared with the HF-offspring. Conclusion: This study indicates the potential protective effects of maternal GTE intake during lactation on HF diet-induced hepatic lipid accumulation in adult male rat offspring and the possible underlying mechanisms.

  DOI

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