OOSAKI Yuuki

写真a

Affiliation

School of Medicine, Department of Anatomy (1)

Job title

Professor
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Degree 【 display / non-display 】

  • Tottori University   Ph.D. (Life Science)

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Research Experience 【 display / non-display 】

  • 2021.09
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    Now

    Sapporo Medical University   Division of Cell and Tissue Morphology, Department of Anatomy, School of Medicine   Professor

  • 2017.06
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    2021.08

    Nagoya University Graduate School of Medicine   Department of Anatomy and Molecular Cell Biology   Associate Proferssor

  • 2014.07
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    2017.05

    Nagoya University Graduate School of Medicine   Department of Anatomy and Molecular Cell Biology   Lecturer

  • 2012.04
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    2014.06

    Nagoya University Graduate School of Medicine   Department of Anatomy and Molecular Cell Biology   Assistant Professor

  • 2010.04
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    2012.03

    University of Helsinki   Department of Anatomy, Faculty of Medicine   postdoctoral researcher

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Professional Memberships 【 display / non-display 】

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    日本組織細胞化学会

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    日本解剖学会

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    日本細胞生物学会

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    日本生化学会

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Research Areas 【 display / non-display 】

  • Life sciences   Anatomy  

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Research Interests 【 display / non-display 】

  • Vesicle transport

  • Hepatocytes

  • Lipid metabolism

  • Lipid droplets

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Papers 【 display / non-display 】

  • Pathological significance of intranuclear structures in liver biopsy samples.

    Norihiro Imai, Yuki Ohsaki, Jinglei Cheng, Hanna Kawecka, Jingjing Zhang, Fumitaka Mizuno, Taku Tanaka, Shinya Yokoyama, Kenta Yamamoto, Takanori Ito, Yoji Ishizu, Takashi Honda, Tetsuya Ishikawa, Michał Woźniak, Hiroaki Wake, Hiroki Kawashima

    Hepatology research : the official journal of the Japan Society of Hepatology   55 ( 7 ) 1065 - 1074  2025.07  [International journal]

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    AIM: Glycogenated nuclei (GN) are glycogen deposits within the nuclei and are a frequent pathological finding in metabolic dysfunction-associated steatotic liver disease. This study aimed to investigate the relationship between GN and two morphologically distinct types of intranuclear lipid droplets in liver biopsy specimens and to explore their respective pathological significance. METHODS: We analyzed 135 liver biopsy specimens. A portion of the liver biopsy specimen was examined using transmission electron microscopy (TEM) to investigate intranuclear lipid droplets in hepatocytes. Nuclear inclusion bodies with clear boundaries and unstained areas on hematoxylin and eosin staining were identified as nuclear glycogen. RESULTS: TEM revealed nucleoplasmic lipid droplets (nLD) in 65% of liver biopsy specimens and invagination of cytoplasmic lipid droplets into the nucleus in 30% of specimens. In contrast, light microscopy detected GN in 82% of specimens. No significant correlations were observed between the frequencies of the two types of intranuclear lipid droplets and nuclear glycogen levels. A significant positive correlation was observed between the frequency of nLD and transaminase levels. Glycogenated nuclei were frequently observed in liver biopsy specimens from patients with MASLD; however, their frequency did not significantly correlate with the degree of hepatic steatosis. Instead, a significant positive correlation was observed between nuclear glycogen and blood HbA1c levels. CONCLUSIONS: The two types of intranuclear lipid droplets and nuclear glycogen observed in liver biopsy specimens showed no significant correlation in their formation frequencies, suggesting that they possess distinct pathological significance.

    DOI PubMed

  • Region-specific assessment of the mechanical properties of each hamstring muscle in human cadavers using shear wave elastography.

    Gakuto Nakao, Taiki Kodesho, Kazuma Yamagata, Risa Adachi, Koki Ishiyama, Kazuyoshi Kozawa, Kota Watanabe, Yuki Ohsaki, Masaki Katayose, Keigo Taniguchi

    Clinical biomechanics (Bristol, Avon)   127   106586 - 106586  2025.07  [International journal]

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    BACKGROUND: Understanding regional mechanical properties of individual hamstring muscles is essential for accurately interpreting their functional behavior during elongation. However, how mechanical stress varies within muscles during elongation remains unclear. This study aimed to examine whether mechanical stresses differ among the hamstring muscles and at various regions within each muscle. METHODS: Fifteen cadavers were dissected to study the biceps femoris long head, semitendinosus, and semimembranosus muscles. Proximal and distal tendons were attached to a mechanical testing machine, and muscles were stretched from slack length to 8 % strain. Muscle length was measured with a tape measure, and anatomical cross-sectional areas at proximal (33 %) and distal (67 %) regions were determined using B-mode ultrasonography. Strain and stress were calculated to assess mechanical properties, and shear modulus was measured using shear wave elastography at the same regions. FINDINGS: A linear correlation between shear modulus and stress was found for all hamstring muscles (P < 0.01). Significant interactions among muscle, region, and strain were observed, with post-hoc tests revealing that the biceps femoris long head and semimembranosus had higher shear modulus than the semitendinosus after 0.5 % strain. The proximal biceps femoris long head showed increased shear modulus after 5 % strain, and proximal semimembranosus showed higher values after 0.5 % strain compared with the distal region. INTERPRETATION: The study findings reveal region-specific variations in the mechanical properties both among and within the hamstring muscles. Combining shear wave elastography with mechanical testing offers a non-destructive approach for characterizing these variations in passive muscle behavior.

    DOI PubMed

  • Ultrasound-guided serratus posterior superior muscle block: an anatomical study investigating the extent of injected dye and the mechanism of action of a simulated injection in Thiel soft-embalmed cadavers.

    Atsushi Sawada, Tatsuya Kunigo, Yuki Ohsaki, Kanna Nagaishi, Michiaki Yamakage

    Journal of anesthesia    2025.04  [Domestic journal]

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    PURPOSE: The extent of local anesthetic spread and mechanism of action of serratus posterior superior muscle (SPSM) block is still debatable. This cadaveric study aimed to evaluate the anatomical spread of 30 or 20 mL of dye following a simulated SPSM block in Thiel soft-embalmed cadavers. METHODS: Simulated SPSM block injections were administered bilaterally in four cadavers (left side: 30 mL, right side: 20 mL). Anatomical dissection was performed to evaluate the extent of spread of the injected dye over the ribcage, and to document staining of the musculature of the back following a simulated SPSM block. RESULTS: The extents of spread (mean ± SD) of 30 mL and 20 mL of dye over the ribcage were 8.5 ± 3.9 cm and 5.5 ± 1.6 cm, respectively. Dye spread to the peri-scapular fascia was observed in all four of the simulated SPSM blocks with 30 mL of dye, but not with 20 mL. Dye spread into the rhomboid major muscle was observed in two of the simulated SPSM blocks with 30 mL of dye. CONCLUSION: Our findings suggest that the SPSM block using 30 mL of dye has a tendency to spread wider compared to the SPSM block using 20 mL of injectate, and that the block might serve as an interfascial block rather than a segmental nerve block. Further studies in a large sample of human participants are required to confirm the optimal volume of local anesthetic in the SPSM block.

    DOI PubMed

  • Ultrasound-assisted middle thoracic epidural catheter placement utilizing the most dorsal sites of bilateral transverse process roots as anatomical landmarks: A cadaveric observational study and a clinical randomized controlled trial.

    Tatsuya Kunigo, Yusuke Yoshikawa, Shunichi Niki, Masahiro Ohtani, Mami Muraki, Asako Nitta, Yuki Ohsaki, Kanna Nagaishi, Michiaki Yamakage

    Journal of clinical anesthesia   101   111740 - 111740  2025.02  [International journal]

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    STUDY OBJECTIVE: We developed an innovative method for ultrasound-assisted thoracic epidural catheter placement and assessed its potential to reduce procedural duration for trainees. DESIGN: A cadaveric observational study and a clinical randomized controlled trial. SETTING: Sapporo Medical University Hospital. PATIENTS: A total of 52 adult patients scheduled for thoracic or abdominal surgery and four cadavers. INTERVENTIONS: Patients were randomly assigned to either group receiving conventional palpation (conventional group) or combination of the ultrasound examination and conventional palpation (ultrasound group). MEASUREMENTS: The primary outcome was total procedure time (sum of skin marking time and needling time) by trainees. The secondary outcomes were (1) skin marking time, (2) needling time, (3) multiple skin punctures, (4) needle redirection, (5) complications, and (6) failed cases. MAIN RESULTS: Through dissection of four cadavers, the most dorsal site of the transverse process root was identifiable by ultrasound and the reliable indicator of the interlaminar space. We devised ultrasound-assisted middle thoracic epidural catheter placement utilizing the most dorsal sites of bilateral transverse process roots as anatomical landmarks. Trainees in the ultrasound group had significantly longer skin marking time and significantly shorter needling time than those in the conventional group (107 [87-158] vs 46 s [34-54] s, p < 0.001 and 197 [156-328] vs 341 [303-488] s, p = 0.003). Consequently, there was no significant difference between the two groups in total procedure time (326 [263-467] s vs 391 [354-533] s, p = 0.167). Moreover, the probability of trainee failure in epidural anesthesia was significantly lower in the ultrasound group (2/26 [17.7 %] vs 10/26 [38.5 %], p = 0.019). CONCLUSIONS: Our novel technique for thoracic epidural catheter placement resulted in expedited needling and enhanced success rates among trainees, although there was no significant difference between total procedure time when using ultrasound guidance and that when using conventional palpation.

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  • Passive muscle tension changes in the biceps femoris long head after biceps femoris short head detachment: A human cadaver study.

    Gakuto Nakao, Kazuma Yamagata, Risa Adachi, Koki Ishiyama, Kazuyoshi Kozawa, Kota Watanabe, Yuki Ohsaki, Kousuke Shiwaku, Norio Hayashi, Masaki Katayose, Keigo Taniguchi

    Journal of biomechanics   179   112480 - 112480  2025.01  [International journal]

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    The functional role of the biceps femoris short head (BFsh) remains unclear. Clarifying the functional role of each biceps femoris head may provide useful insights into the reduction of biceps femoris long head (BFlh) injuries. This study aimed to clarify whether the passive tension in the BFlh would change with BFsh detachment using cadavers. The shear modulus of the BFlh and BFsh was measured using ultrasonic shear wave elastography as an index of passive tension in three tissue processing conditions (intact, removal of all tissues from skin to deep fascia, and BFsh detachment) in four limb positions, with hip [H0°, H90°] and knee [K0°, K90°] joint angles under each tissue processing condition. The measurement site was the distal 30 % of the line connecting the sciatic tuberosity (100 %) and fibular head (0 %). Three-way analysis of variance was conducted with muscles, tissue processing, and positions as factors, which revealed a significant interaction (P < 0.01). The post-test results indicated that the BFlh was significantly higher than the BFsh at H90° and K0° before tissue processing; however, no difference was observed between the muscles after skin and deep fascia removal. After BFsh detachment, the shear modulus of the BFsh decreased, whereas that of the BFlh significantly increased (P < 0.01), suggesting that the BFsh might be involved in the passive tension reduction of the BFlh in a lengthened position, as the shear modulus of the BFlh increased after detachment.

    DOI PubMed

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Misc 【 display / non-display 】

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Research Projects 【 display / non-display 】

  • 脂肪滴の細胞質および核内での生理機能解明

    基盤研究(B)

    Project Year :

    2024.04
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    2027.03
     

    大崎 雄樹, 和田 亘弘

  • 脂肪滴の核内での形成機構と生理機能の形態学的解析

    Project Year :

    2023.04
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    2025.03
     

    大﨑雄樹

    Authorship： Principal investigator

  • 核内脂肪滴の肝疾患における意義

    Project Year :

    2023.04
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    2025.03
     

    大﨑雄樹

    Authorship： Principal investigator

  • 核膜変形機構と核内脂質代謝の細胞老化への影響の解明

    Project Year :

    2023.04
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    2024.03
     

    大﨑雄樹

    Authorship： Principal investigator

  • 脂肪滴による核内蛋白質機能制御機構の解明

    Project Year :

    2022.08
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    2027.05
     

    大﨑雄樹

    Authorship： Principal investigator

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Presentations 【 display / non-display 】

  • 脂肪滴の異所性形成に関与する核膜形態変化

    大崎 雄樹, 和田 亘弘  [Invited]

    第47回日本分子生物学会年会 

    Presentation date： 2024.11

    Event date：
    2024.11
    　
    　

  • 小胞体・核膜における脂肪滴の形成制御

     [Invited]

    第97回日本生化学会大会 

    Presentation date： 2024.11

    Event date：
    2024.11
    　
    　

  • 脂肪滴形成に関わる膜形態制御機構

    大崎 雄樹  [Invited]

    第65回日本組織細胞化学会総会・学術集会 

    Presentation date： 2024.10

    Event date：
    2024.10
    　
    　

  • 脂肪滴のDNA損傷修復機構への関与

    大﨑 雄樹, 和田 亘弘, 菊地 鴻太, 酒井 恒

    第129回日本解剖学会総会・全国学術集会 

    Presentation date： 2024.03

    Event date：
    2024.03
    　
    　

  • 核内脂肪滴形成に関与する核膜形態維持分子

    大﨑 雄樹, 和田 亘弘, 本城 愛子, 室松 悠希

    第96回日本生化学会大会 

    Presentation date： 2023.11

    Event date：
    2023.10
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    2023.11

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