Yasuyuki Miyoshi

Okayama University, Okayama, Okayama, Japan

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Publications (61)133.74 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Some cases with lumbar degenerative diseases require multi-level fusion surgeries. At our institute, 27 and 4 procedures of 3- and 4-level fusion were performed out of a total 672 posterior lumbar interfusions (PLIFs) on patients with lumbar degenerative disease from 2005 to 2010. We present 2 osteoporotic patients who developed proximal vertebral body fracture after 4-level fusion. Both cases presented with gait disability for leg pain by degenerative lumbar scoliosis and canal stenosis at the levels of L1/2-4/5. After 4-level fusion using L1 as the upper instrumented vertebra, proximal vertebral body fractures were found along with the right pedicle fractures of L1 in both cases. One of these patients, aged 82 years, was treated as an outpatient using a hard corset for 24 months, but the fractures were exacerbated over time. In the other patient, posterolateral fusion was extended from Th10 to L5. Both patients can walk alone and have been thoroughly followed up. In both cases, the fracture of the right L1 pedicle might be related to the subsequent fractures and fusion failure. In consideration of multi-level fusion, L1 should be avoided as an upper instrumented vertebra to prevent junctional kyphosis, especially in cases with osteoporosis and flat back posture.
    Acta medica Okayama 06/2013; 67(3):197-202. · 0.65 Impact Factor
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    ABSTRACT: Epilepsy is a chronic neurological disorder, which presents with various forms of seizures. Traditional treatments, including medication using antiepileptic drugs, remain the treatment of choice for epilepsy. Recent development in surgical techniques and approaches has improved treatment outcomes. However, several epileptic patients still suffer from intractable seizures despite the advent of the multimodality of therapies. In this article, we initially provide an overview of clinical presentation of epilepsy then describe clinically relevant animal models of epilepsy. Subsequently, we discuss the concepts of regenerative medicine including cell therapy, neuroprotective agents, and electrical stimulation, which are reviewed within the context of our data.
    International Journal of Molecular Sciences 01/2013; 14(12):23390-401. · 2.46 Impact Factor
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    ABSTRACT: An 18-year-old woman with a 2-year history of hypertension and headache was diagnosed with noradrenalin-secreting bilateral adrenal pheochromocytomas with paragangliomas in the background of von Hippel-Lindau disease with family histories and a missense mutation, 712C to T (Arg167Trp) in the VHL gene. She had optic disc hemangioma in the left eye which gradually enlarged and caused serous retinal detachment on the macula in one year. Low-dose external beam radiation (20 Gy) was administered to the left eye using a lens-sparing single lateral technique. She underwent craniotomy for cerebellar hemangioblastoma at the age of 22 years and total pancreatectomy for multiple neuroendocrine tumors at the age of 24 years. In the 6-year follow-up period after the radiotherapy, the optic disc hemangioma gradually reduced in size and its activity remained low, allowing good central vision to be maintained. External beam radiation is recommended as a treatment option for the initial therapy for optic disc hemangioma.
    Acta medica Okayama 04/2011; 65(2):135-41. · 0.65 Impact Factor
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    ABSTRACT: Posterior reversible encephalopathy syndrome (PRES) is a clinico-neuroradiological entity with typical symptoms and symmetric high-signal intensity lesions in the bilateral parieto-occipital lobes on T2-weighted or fluid-attenuated inversion recovery (FLAIR) MRI. We described three patients with PRES of varied etiologies. Patient 1 was a young man with severe hypertension who presented with headache and visual disturbance. Patient 2 had leukemia and was receiving umbilical cord blood cell transplantation with immunosuppressant, and developed PRES with convulsions. Patient 3 was a pregnant woman with renal failure, who repeatedly developed PRES with convulsions. FLAIR and apparent diffusion coefficient mapping were useful in detecting PRES lesions in our patients, although diffusion-weighted imaging and CT scans had limited use in the diagnosis. Adequate and prompt treatment with antihypertensive medication immediately ameliorated the symptoms, with improvement of abnormal MRI findings. In previous reports, delayed diagnosis might have affected the prognosis. Further work on the clinical manifestations of PRES and its therapy is required.
    Journal of Clinical Neuroscience 03/2011; 18(3):406-9. · 1.25 Impact Factor
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    ABSTRACT: Increased oxidative stress contributes to pathogenesis of Parkinson's disease (PD). 8-hydroxy-2'-deoxyguanosine (8-OHdG) is the oxidation product most frequently measured as an indicator of oxidative DNA damage. Several studies have shown increased 8-OHdG in PD patients. There are few basic laboratory data examining 8-OHdG levels in animal models of PD. In this study, we utilized hemiparkinsonian model of rats induced by intrastriatal injection of 6-hydroxydopamine (6-OHDA). The urinary 8-OHdG level was measured in relation to behavioral and pathological deficits arising from 6-OHDA-induced neurotoxic effects on the nigrostriatal dopaminergic pathway. All rats were subjected to a series of behavioral tests for 42 days after 6-OHDA injection. We collected urine samples with subsequent measurement of 8-OHdG level using ELISA kits. For immunohistochemical evaluation, tyrosine hydroxylase (TH) staining was performed. Significant increments in urinary 8-OHdG level were observed continuously from day 7 until day 35 compared to control group, which showed a trend of elevation as early as day 3. Such elevated urinary 8-OHdG level significantly correlated with all of the behavioral deficits measured here, suggesting that urinary 8-OHdG level provides a good index of severity of parkinsonism. Urinary 8-OHdG level also had a significant positive correlation with the survival rate of dopaminergic fibers or neurons, advancing the concept that oxidative stress during the early phase of 6-OHDA neurotoxicity may correspond to disease progression closely approximating neuronal degeneration in the nigrostriatal dopaminergic system. The present results demonstrate that alterations in urinary 8-OHdG level closely approximate onset and disease progression in PD. J. Cell. Physiol. 226: 1390–1398, 2011. © 2010 Wiley-Liss, Inc.
    Journal of Cellular Physiology 02/2011; 226(5):1390 - 1398. · 4.22 Impact Factor
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    Takao Yasuhara, Yasuyuki Miyoshi, Isao Date
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    ABSTRACT: A case of a Chiari malformation with an extraordinarily thick occipital bone is described. The thick occipital bone might make the posterior fossa narrow with consequent herniation of the cerebellar tonsils to the foramen magnum and formation of a syrinx. At dural plasty, well-developed marginal and occipital sinuses should be deliberately handled with the preservation of normal venous drainage. This case gives us the essence of the occurrence mechanisms of Chiari malformation and foramen magnum decompression.
    Acta medica Okayama 02/2011; 65(1):59-61. · 0.65 Impact Factor
  • Brain and nerve = Shinkei kenkyū no shinpo 02/2011; 63(2):182-3.
  • Takao Yasuhara, Yasuyuki Miyoshi, Isao Date
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    ABSTRACT: A 78-year-old man presented with a rare massive subarachnoid hematoma (SAH) in the cervical spine after coronary stenting for angina pectoris. Chest pain and electrocardiographic changes were resolved after administration of coronary dilator and coronary stenting, but shoulder pain persisted. At 6 hours after stenting, left hemiparesis was found with deteriorated shoulder pain. Computed tomography and magnetic resonance imaging revealed massive SAH in the cervical spine. Emergent hematoma evacuation with laminoplasty was performed because of rapid progression of the hemiparesis and pain. The hemiparesis was ameliorated after surgery. Spinal hematoma should be considered in the differential diagnosis in patients receiving anti-platelet or anti-coagulant drugs with rapid progression of pain.
    Neurologia medico-chirurgica 01/2011; 51(9):664-6. · 0.49 Impact Factor
  • Yasuyuki Miyoshi, Takao Yasuhara, Isao Date
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    ABSTRACT: A 29-year-old man presented with a rare case of far-out foraminal stenosis with radiculopathy caused by osteophyte formation secondary to an anomalous articulation between the transverse process and the sacral ala. Diagnosis of unilateral far-out foraminal entrapment of the L5 spinal nerve below a transitional vertebra (TV) depended on selective radiculography and nerve root block. Computed tomography after selective radiculography clearly demonstrated foraminal entrapment of the L5 nerve root via the osteophytes. The patient underwent posterior decompression by resection of the osteophytes using an operating microscope and experienced good relief of radicular pain. This case illustrates the effectiveness and some refinements of posterior decompression for radicular pain caused by far-out foraminal stenosis below a TV and compression of the L5 spinal nerve.
    Neurologia medico-chirurgica 01/2011; 51(2):153-6. · 0.49 Impact Factor
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    ABSTRACT: A 27-year-old woman presented with a case of primary medulla oblongata germinoma manifesting as sleep apnea, aspiration pneumonia, and left hemiparesis. Magnetic resonance (MR) imaging revealed a dorsal mass in the medulla oblongata with heterogeneous enhancement by gadolinium (Gd). Emergent biopsy and foramen magnum decompression with C1 laminectomy were performed because of rapid worsening of her symptoms. The histological diagnosis was germinoma. Subsequently she received chemoradiation therapy with subsequent amelioration of her neurological deficits and disappearance of enhancement on MR imaging with Gd. Primary medulla oblongata germinoma is rare and difficult to diagnose preoperatively. However, correct diagnosis and subsequent adequate chemoradiation therapy is possible by understanding the common characteristics of the disease. Germinoma should be included in the differential diagnosis of midline medullary lesion in young patients, and biopsy should be considered.
    Neurologia medico-chirurgica 01/2011; 51(4):326-9. · 0.49 Impact Factor
  • Yasuyuki Miyoshi, Takao Yasuhara, Isao Date
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    ABSTRACT: A 11-year-old female with Noonan syndrome presented with occipito-atlantal dislocation and upper cervical cord compression due to C1 dysplasia and basilar invagination. Computed tomography (CT) of the cervical spine showed dysplasia of the C1 posterior arch and bilateral dislocation of the occipito-atlantal joints. Dynamic lateral radiography revealed no instability at the occipito-atlantal joints. CT also demonstrated basilar invagination. The tip of the odontoid process extended above the Chamberlain line by 9 mm and the McGregor line by 10 mm. Whole spinal radiography showed no scoliosis. C1 laminectomy was performed with instrumented occipito-C2 fixation. The postoperative course was uneventful, and magnetic resonance imaging revealed sufficient decompression of the upper cervical cord at 2 months after surgery. CT demonstrated solid bony fusion between the occipital bone and C2 at 8 months after surgery. Cervical neuraxial malformations are rare in patients with Noonan syndrome.
    Neurologia medico-chirurgica 01/2011; 51(6):463-6. · 0.49 Impact Factor
  • Takao Yasuhara, Yasuyuki Miyoshi, Isao Date
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    ABSTRACT: The "mist irrigation system" (MIS) is a new and effective method at drilling in spinal surgery. In this report, MIS is introduced with subsequent demonstration that visibility at drilling is better with MIS because of the reduction of smoke, blood and irrigation water. Additionally using a 5 mm-thick acryl plate, the time for perforation by drilling and temperature after drilling with MIS, drip-irrigation (DI) or no irrigation, were measured respectivily. Using the acryl plate significantly reduced drilling time and high temperature after perforation in the group without irrigation were recognized, compared to cases in the groups with MIS or DI. The results might indicate that the high temperature of the drill might melt the acryl plate immediately. As a conclusion, MIS might help surgeons to drill in the deep and narrow operative field. Additionally it might help to reduce the risks of heat injury to neuronal tissue by cooling efficiently.
    No shinkei geka. Neurological surgery 12/2010; 38(12):1103-7. · 0.13 Impact Factor
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    ABSTRACT: Deep brain stimulation (DBS) is used to treat a variety of neurological disorders including Parkinson's disease. In this study, we explored the effects of striatal stimulation (SS) in a rat model of chronic-phase ischemic stroke. The stimulation electrode was implanted into the ischemic penumbra at 1 month after middle cerebral artery occlusion (MCAO) and thereafter continuously delivered SS over a period of 1 week. Rats were evaluated behaviorally coupled with neuroradiological assessment of the infarct volumes using magnetic resonance imaging (MRI) at pre- and post-SS. The rats with SS showed significant behavioral recovery in the spontaneous activity and limb placement test compared to those without SS. MRI visualized that SS also significantly reduced the infarct volumes compared to that at pre-SS or without SS. Immunohistochemical analyses revealed a robust neurogenic response in rats that received SS characterized by a stream of proliferating cells from the subventricular zone migrating to and subsequently differentiating into neurons in the ischemic penumbra, which exhibited a significant GDNF upregulation. In tandem with this SS-mediated neurogenesis, enhanced angiogenesis was also recognized as revealed by a significant increase in VEGF levels in the penumbra. These results provide evidence that SS affords neurorestoration at the chronic phase of stroke by stimulating endogenous neurogenesis and angiogenesis.
    Cell Transplantation 11/2010; 20(7):1049-64. · 4.42 Impact Factor
  • Clinical neurology and neurosurgery 11/2010; 113(3):239-42. · 1.30 Impact Factor
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    ABSTRACT: Brain-derived neurotrophic factor (BDNF) is a well neurotrophic factor with neuroprotective potentials for various diseases in the central nervous system. However several previous studies demonstrated that BDNF might deteriorate symptoms for epilepsy model of animals by progression of abnormal neurogenesis. We hypothesized that continuous administration of BDNF at low dose might be more effective for epilepsy model of animals because high dose of BDNF was used in many studies. BDNF-secreting cells were genetically made and encapsulated for transplantation. Rats receiving BDNF capsule showed significant amelioration of seizure stage and reduction of the number of abnormal spikes at 7 days after kainic acid administration, compared to those of control group. The number of BrdU and BrdU/doublecortin positive cells in the hippocampus of BDNF group significantly increased, compared to that of control group. NeuN positive cells in the CA1 and CA3 of BDNF group were significantly preserved, compared to control group. In conclusion, low dose administration using encapsulated BDNF-secreting cells exerted neuroprotective effects with enhanced neurogenesis on epilepsy model of rats. These results might suggest the importance of the dose and administrative way of this neurotrophic factor to the epilepsy model of animals.
    Brain research 10/2010; 1368:281-9. · 2.46 Impact Factor
  • Yasuyuki MIYOSHI, Takao YASUHARA, Masako OMORI, Isao DATE
    Neurologia Medico-chirurgica - NEUROL MED-CHIR. 01/2010; 50(8):677-682.
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    ABSTRACT: Mesenchymal stem cells (MSCs) are pluripotent stem cells derived from bone marrow with secretory functions of various neurotrophic factors. Stromal cell-derived factor-1alpha (SDF-1alpha) is also reported as one of chemokines released from MSCs. In this research, the therapeutic effects of MSCs through SDF-1alpha were explored. 6-hydroxydopamine (6-OHDA, 20 microg) was injected into the right striatum of female SD rats with subsequent administration of GFP-labeled MSCs, fibroblasts, (i.v., 1 x 107 cells, respectively) or PBS at 2 hours after 6-OHDA injection. All rats were evaluated behaviorally with cylinder test and amphetamine-induced rotation test for 1 month with consequent euthanasia for immunohistochemical evaluations. Additionally, to explore the underlying mechanisms, neuroprotective effects of SDF-1alpha were explored using 6-OHDA-exposed PC12 cells by using dopamine (DA) assay and TdT-mediated dUTP-biotin nick-end labeling (TUNEL) staining. Rats receiving MSC transplantation significantly ameliorated behaviorally both in cylinder test and amphetamine-induced rotation test compared with the control groups. Correspondingly, rats with MSCs displayed significant preservation in the density of tyrosine hydroxylase (TH)-positive fibers in the striatum and the number of TH-positive neurons in the substantia nigra pars compacta (SNc) compared to that of control rats. In the in vitro study, SDF-1alpha treatment increased DA release and suppressed cell death induced by 6-OHDA administration compared with the control groups. Consequently, MSC transplantation might exert neuroprotection on 6-OHDA-exposed dopaminergic neurons at least partly through anti-apoptotic effects of SDF-1alpha. The results demonstrate the potentials of intravenous MSC administration for clinical applications, although further explorations are required.
    BMC Neuroscience 01/2010; 11:52. · 3.00 Impact Factor
  • Yasuyuki Miyoshi, Takao Yasuhara, Masako Omori, Isao Date
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    ABSTRACT: A 2-month-old infant presented with a cervical intramedullary spinal cord cavernous angioma manifesting as left hemiparesis caused by hematomyelia. Osteoplastic laminotomy of the cervical spine was carried out with subsequent microsurgical excision of the intramedullary spinal cord cavernous angioma. Magnetic resonance imaging revealed no residual tumor. At 25 months after the surgery, she presented no neurological deficit without recurrence and cervical deformity. This case of infantile intramedullary spinal cord cavernous angioma presenting with cervical hematomyelia shows osteoplastic laminotomy of the cervical spine might be helpful to prevent consequent cervical deformity in pediatric cases.
    Neurologia medico-chirurgica 01/2010; 50(8):677-82. · 0.49 Impact Factor
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    ABSTRACT: Recent studies demonstrate that rehabilitation ameliorates physical and cognitive impairments of patients with stroke, spinal cord injury, and other neurological diseases and that rehabilitation also has potencies to modulate brain plasticity. Here we examined the effects of compulsive exercise on Parkinson's disease model of rats. Before 6-hydroxydopamine (6-OHDA, 20 microg) lesion into the right striatum of female SD rats, bromodeoxyuridine (BrdU) was injected to label the proliferating cells. Subsequently, at 24 h after the lesion, the rats were forced to run on the treadmill (5 days/week, 30 min/day, 11 m/min). As behavioral evaluations, cylinder test was performed at 1, 2, 3, and 4 weeks and amphetamine-induced rotational test was performed at 2 and 4 weeks with consequent euthanasia for immunohistochemical investigations. The exercise group showed better behavioral recovery in cylinder test and significant decrease in the number of amphetamine-induced rotations, compared to the non-exercise group. Correspondingly, significant preservation of tyrosine hydroxylase (TH)-positive fibers in the striatum and TH-positive neurons in the substantia nigra pars compacta (SNc) was demonstrated, compared to the non-exercise group. Additionally, the number of migrated BrdU- and Doublecortin-positive cells toward the lesioned striatum was increased in the exercise group. Furthermore, brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor increased in the striatum by exercise. The results suggest that exercise exerts neuroprotective effects or enhances the neuronal differentiation in Parkinson's disease model of rats with subsequent improvement in deteriorated motor function.
    Brain research 11/2009; 1310:200-7. · 2.46 Impact Factor
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    ABSTRACT: We explored the effects of exogenous and endogenous erythropoietin (EPO) in a seizure model of rat. Adult male Fischer 344 rats received continuous intraventricular infusion of EPO dissolved in saline containing 1mg/ml of rat serum albumin, anti-EPO antibody, saline containing 1mg/ml of rat serum albumin or combined EPO and neuropeptide Y (NPY) Y2-receptor antagonist. Animals were behaviorally evaluated for seizure development over 6h after kainic acid injection followed by immunohistochemical assays. Mortality rate, seizure severity, apoptotic cell death and abnormal cell proliferation in the hippocampus of EPO-treated epileptic rats were significantly attenuated, compared to control rats. Anti-EPO antibody in non-EPO-treated animals worsened seizures and CA1 neuronal cell death, while NPY Y2-receptor antagonist cancelled the therapeutic effects of exogenous EPO. Both exogenous and endogenous EPO might modulate seizure severity and protect the hippocampal neurons in epileptic rats, via novel mechanistic pathways involving blockade of epileptogenic cell formation coupled with NPY receptor modulation in the hippocampus.
    Brain research 09/2009; 1296:127-36. · 2.46 Impact Factor

Publication Stats

749 Citations
133.74 Total Impact Points

Institutions

  • 1999–2011
    • Okayama University
      • Department of Neurological Surgery
      Okayama, Okayama, Japan
  • 2003
    • Dokkyo Medical University
      • Department of Urological Surgery
      Tochigi, Tochigi-ken, Japan