Yasuo Kokubo

Dr. Yasuo Kokubo


Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 September 2008 in Journal of Neurosurgery: Spine
Verified
Journal Article
Closed access
YKYasuo Kokubo
Yasuo Kokubo
KUKenzo Uchida
Kenzo Uchida
SKShigeru Kobayashi
Shigeru Kobayashi
TYTakafumi Yayama
Takafumi Yayama
RSRyuichiro Sato
Ryuichiro Sato
HBHisatoshi Baba
Hisatoshi Baba
Object: In this paper the authors' goal was to identify histological and immunohistochemical differences between cervical disc herniation and spondylosis. Methods: A total of 500 cervical intervertebral discs were excised from 364 patients: 198 patients with disc herniation and 166 patients with spondylosis. We examined en bloc samples of endplate-ligament-disc complexes. Types of herniation and graded degrees of disc degeneration on MR images were examined histologically and immunohistochemically. Results: The herniated discs showed granulation tissue, newly developed blood vessels, and massive infiltration of CD68-positive macrophages, which surrounded the herniated tissue mainly in the ruptured outer layer of the anulus fibrosus. The vascular invasion was most significant in uncontained (extruded)-type herniated discs. Chondrocytes positive for matrix metalloproteinase (MMP)–3, tumor necrosis factor (TNF)–α, basic fibroblast growth factor (bFGF), and vascular endothelial growth factor (VEGF) were abundant in both herniated and spondylotic discs. Free nerve fibers, positive for nerve growth factor (NGF), neurofilament 68, growth-associated protein (GAP)-43, and substance P, were strongly apparent in and around the outer layer of uncontained (extruded)-type herniated discs, with enhanced expression of NGF. The authors observed that herniated discs showed more advanced degeneration in the outer layer of the anulus fibrosus around the granulation tissue than spondylotic discs. On the other hand, spondylotic discs showed more advanced degeneration in the cartilaginous endplate and inner layer of the anulus fibrosus than herniated discs. Spondylotic discs also had thicker bony endplates and expressed TNFα and MMP-3 more diffusely than herniated discs, especially in the inner layer of the anulus fibrosus. Conclusions: The authors' results indicate that herniated and spondylotic intervertebral discs undergo different degenerative processes. It is likely that TNFα, MMP-3, bFGF, and VEGF expression is upregulated via the herniated mass in the herniated intervertebral discs, but by nutritional impairment in the spondylotic discs. Macrophage accumulation around newly formed blood vessels in the herniated disc tissues seemed to be regulated by MMP-3 and TNFα expression, and both herniated and spondylotic discs exhibited marked neoangiogenesis associated with increased bFGF and VEGF expression. Nerve fibers were associated with NGF overexpression in the outer layer of the anulus fibrosus as well as in endothelial cells of the small blood vessels.

1 January 2017 in Journal of Orthopaedic Surgery
Verified
Journal Article
Open access
YKYasuo Kokubo
Yasuo Kokubo
HOHisashi Oki
Hisashi Oki
DSDaisuke Sugita
Daisuke Sugita
KTKenichi Takeno
Kenichi Takeno
TMTsuyoshi Miyazaki
Tsuyoshi Miyazaki
HNHideaki Nakajima
Hideaki Nakajima
The purpose of this study was to evaluate factors that correlated with unsatisfactory short- and long-term outcome in patients who sustained unstable pelvic ring fracture. The study subjects of this study were those of type B and C pelvic ring fractures (82 patients; mean age 54 years). Age, gender, associated injuries, fracture type, Injury Severity Score rating and treatment methods were assessed, and Majeed score for functional outcome and radiographic studies at 1 year after injury (short-term) and at final follow-up (long-term), with mean follow-up of 98 months were analyzed. Significant univariate factors (p < 0.05) were entered in a multivariate logistic regression model to determine the independent predictors of unsatisfactory functional outcome. Univariate analysis showed that fractures of the lower extremity, nerve damage, conservative treatment, and radiological outcome correlated with unsatisfactory short-term functional outcome, while female gender, brain injury, nerve damage, conservative treatment, fracture location at the posterior portion of pelvic ring, radiological outcome, and pure sacroiliac dislocation only for type C fracture correlated with unsatisfactory long-term outcome. Multiple logistic regression analysis identified fractures of the lower extremity (odds ratio (OR): 5.364), conservative treatment (OR: 13.690), and nerve damage (OR: 21.392) as determinants of unsatisfactory short-term functional outcome and nerve damage (OR: 66.926) and poor radiological results (OR: 33.944) as determinant of long-term functional outcome. In patients with unstable pelvic ring injury, fractures of the lower extremity, conservative therapy, and nerve damage influenced short-term functional outcome, while that nerve damage and the pelvic ring displacement over 20 mm negatively affected long-term outcome.

5 July 2012 in European Journal of Orthopaedic Surgery & Traumatology
Verified
Journal Article
Closed access
PDF file
YKYasuo Kokubo
Yasuo Kokubo
KUKenzo Uchida
Kenzo Uchida
KTKenichi Takeno
Kenichi Takeno
TYTakafumi Yayama
Takafumi Yayama
TMTsuyoshi Miyazaki
Tsuyoshi Miyazaki
HBHisatoshi Baba
Hisatoshi Baba

19 January 2012 in European Journal of Orthopaedic Surgery & Traumatology
Verified
Journal Article
Closed access
PDF file
KUKenzo Uchida
Kenzo Uchida
YKYasuo Kokubo
Yasuo Kokubo
TYTakafumi Yayama
Takafumi Yayama
HNHideaki Nakajima
Hideaki Nakajima
TMTsuyoshi Miyazaki
Tsuyoshi Miyazaki
HBHisatoshi Baba
Hisatoshi Baba

1 February 2010 in Journal of Neurosurgery: Spine
Verified
Journal Article
Open access
SKShigeru Kobayashi
Shigeru Kobayashi
EMErisa Sabakaki Mwaka
Erisa Sabakaki Mwaka
HBHisatoshi Baba
Hisatoshi Baba
YKYasuo Kokubo
Yasuo Kokubo
TYTakafumi Yayama
Takafumi Yayama
AMAdam Meir
Adam Meir
Object: The dorsal root ganglion (DRG) should not be overlooked when considering the mechanism of low-back pain and sciatica, so it is important to understand the morphological features of the vascular system supplying the DRG. However, the neurogenic control of intraganglionic blood flow has received little attention in the past. The authors used an immunohistochemical technique to investigate the presence and distribution of autonomic and sensory nerves in blood vessels of the DRG.Methods: Ten Wistar rats were used. To investigate the mechanism of vasomotion on the lumbar DRG, the authors used immunohistochemical methods. Sections were incubated overnight with antisera to tyrosine hydroxylase (TH), aromaticl-amino-acid decarboxylase (AADC), 5-hydroxytryptamine, substance P (SP), calcitonin gene–related peptide (CGRP), vasoactive intestinal peptide (VIP), somatostatin (SOM), neuropeptide Y (NPY), leucine-enkephalin, and cholineacetyl transferase (Ch-E). The avidin-biotin complex method was used as the immunohistochemical procedure, and the sections were observed under a light microscope.Results: In the immunohistochemical study, TH-, AADC-, SP-, CGRP-, VIP-, SOM-, NPY-, and Ch-E–positive fibers were seen within the walls of blood vessels in the DRG. This study revealed the existence of a comprehensive perivascular adrenergic, cholinergic, and peptidergic innervation of intraganglionic blood vessels, with a possible role in neurogenic regulation (autoregulation) of intraganglionic circulation.Conclusions: The presence of perivascular nerve plexuses around intraganglionic microvessels suggests that autonomic nerves play an important role in intraganglionic circulation.

1 July 2020 in The Spine Journal
Verified
Journal Article
Closed access
IKIppei Kitade
Ippei Kitade
HNHideaki Nakajima
Hideaki Nakajima
ATAi Takahashi
Ai Takahashi
MMMayumi Matsumura
Mayumi Matsumura
SSSeiichiro Shimada
Seiichiro Shimada
AMAkihiko Matsumine
Akihiko Matsumine