Hideyo Miyaoka

Showa University, Shinagawa, Tōkyō, Japan

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Publications (10)10.5 Total impact

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    ABSTRACT: Collection of autogenous bone requires new invasion to the other healthy area. β-TCP is replaced by bone with development of bone resorption, but the intensity of β-TCP block is insufficient. We mixed titanium powders in β-TCP powders, and produced a new mold having strong intensity sufficient enough for vertebral fusion. 100% titanium, β-TCP containing 5%, 20%, or 50% of titanium, and 100% β-TCP were implanted in the tibia of rabbits. The tibia was extripated 16 weeks after implantation, and a three-point bending test was performed. The interface of the mold and the bone was observed electron microscopically at 8 and 16 weeks after implantation. The results of three-point bending test showed that the lower β-TCP containing rate was, the more the mean stress increased. In electron microscopic observation, a space was existed between the mold and the bone, and the bone was not unioned 8 weeks after operation in both 5% and 20% β-TCP. However, 16 weeks of post-operation, this space was eliminated and the bone was unioned. But no space was existed at 8 weeks after operation in 100% β-TCP. These results suggest that the higher β-TCP-containing rate was, the more early the mold was fused and stabilized at the implanted site. If the mold is not stabilized at the implanted site, micro-movement exists for a long time period, and callus formation may be stimulated. Therefore, mean stress might have been increased by callus formation in spite of low β-TCP-containing rate. A pluck intensity not affected by callus should be determined. For this purpose, it should be evaluated in the animals implanted the mold for a long period of time.
    No preview · Article · Aug 2009
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    ABSTRACT: Lumber spinal stenosis occupies an important position as a significant factor that reduces activities of daily living in aging society. One of the main lesions is degenerative ligamenta flava where changes such as inflammation, ossification, angiogenesis, cartilaginous degeneration, and calcinosis may be occurred. This time, using degenerative ligamenta flava collected intraoperatively, we compared mRNA expression levels of various genes, cyclooxygenase-2 (COX2)/osteocalcin/endothelin-1/angiopoietin-1/bone morphogenetic protein-2 (BMP2)/interleukin-8 (IL-8), possibly associated with the above changes by dividing into 3 portions as follows: histologically almost normal (unaffected) portion; strongly affected paramedian (interlaminar) portion; and strongly affected portion proximal to bone attachments in the articular capsule. Histological examination was carried out with HE staining of 7 μm-frozen sections derived from ligamenta flava collected intraoperatively using cryostat The mRNAs were extracted with microdissection of the portions after Cresyl Violet staining of the membrane frozen sections. The cDNA clones were replicated, and comparison of expression levels was performed using real-time PCR after reaction with primers for these genes. In the unaffected portion, expression levels of the genes were expected to be less, though, it was higher in IL-8 associated with angiogenesis compared to the other portions. Repair mechanism to micro lesions may lead to scarring and collagen fibers deposition even in the almost normal portion. Moreover, IL-8 expression was observed in the interlaminar and capsular portions, though, angiogenesis may have been more strongly induced in the former. Increased endothelin-1, involving mechanical stress, expression in the capsular portion was expected to actively cause changes, though, various genes associated with cartilage degeneration, ossification, or inflammation were accordingly expressed in the both interlaminar and capsular portions. In the degenerative ligamenta flava, not only endochondral ossification may occur in the bone attachments, but also thickening with bone formation in the portions without continuity with bones.
    No preview · Article · Apr 2009

  • No preview · Article · Apr 2008 · ArgoSpine News & Journal
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    ABSTRACT: Oxidative stress and DNA oxidation play important roles in the induction of ischemic neuronal cell death. However, the subcellular source of oxidized DNA detected by 8-hydroxy-2'-deoxyguanosine (8-OHdG) after ischemia has not been clarified although it is known to increase in the brain after ischemia. One-hour transient ischemia of the middle cerebral artery was induced in mice utilizing an intraluminal filament. The occurrence of superoxide anion as an ethidium (Et) signal, 8-OHdG, cytochrome c release and neuronal cell death were examined using immunohistological and biochemical techniques in sham-operated control (0h) and 1, 3, 6, 24, or 96h after reperfusion. Et signals were prominent in the cortical neurons of ipsilateral hemisphere 3h after reperfusion. Strong 8-OHdG immunoreactivity was observed 3-6h after reperfusion. Immunoassays after cell fractionation revealed a significant increase of 8-OHdG in mitochondria 6h after reperfusion. Immunohistochemistry revealed that the 8-OHdG immunoreactivity colocalized with a neuronal marker, microfilament 200 and a mitochondrial marker, cytochrome oxidase subunit I. Cytochrome c rose in cytoplasm at 6h and TUNEL-positive neurons noted 6-24h after ischemia. The present results suggest the possibility that the mitochondrial damage including mitochondrial DNA oxidation might be responsible for the induction of ischemic neuronal cell death.
    No preview · Article · Sep 2007 · Neuroscience Research
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    ABSTRACT: Catechin, a constituent of tea, possesses various bioactivities. In particular, the most abundant catechin in tea is epigallocatechin gallate (EGCg), which has an anti-inflammatory effect. In the present study, the usability of EGCg for osteomyelitis treatment was examined. Osteomyelitis is a difficult disease to cure, partly due to bone lysis caused by infected osteoblasts. Since bone lysis is promoted by proinflammatory cytokines and the receptor activator of NF-kappaB ligand (RANKL), osteoblasts were infected with Staphylococcus aureus and the effect of EGCg on the production of cytokines was examined. It was found that the production of interleukin 6 and RANKL was suppressed in the osteoblasts treated with EGCg, which indicated an inflammation suppression effect of EGCg in osteomyelitis treatment.
    Preview · Article · Sep 2007 · Journal of Medical Microbiology
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    ABSTRACT: Osteomyelitis is a generally severe infection characterized by inflammatory destruction of the bone. This disease is often refractory and subject to recurrence. Staphylococcus aureus, the Gram-positive organism, is the most common causative agent of osteomyelitis. In bone marrow inflammation caused by the infection with S. aureus, the production of various cytokines is induced. Inflammatory cytokines such as IL-1, IL-6, and TNF-α and receptor activator of NF-κ B ligand (RANKL) are candidate cytokines which are produced by osteoblasts and promote bone resorption. Epigallocatechin gallate (EGCg), the main constituent of tea catechins, exhibits antibacterial, antioxidative, and anti-inflammatory activities. Here, we examined the inhibitory effect of EGCg on production of IL-1α, IL-1β, IL-6, TNF-α, and RANKL in mouse osteoblst infected with S. aureus. Normal osteoblastes produced IL-1α, IL-6, and RANKL but not IL-1β and TNF-a after exposure to S. aureus. In contrast, pretreatment with EGCg to osteoblasts significantly inhibited the production of IL-1α, IL-6, and RANKL. These results indicate that the reduction of IL-1α, IL-6 and RANKL in osteoblasts by EGCg may result in the prevention and therapy for inflammatory bone diseases.
    No preview · Article · Jun 2007
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    ABSTRACT: Severe global ischemia often results in severe damage to the central nervous system of survivors. Hind-limb paralysis is a common deficit caused by global ischemia. Until recently, most studies of global ischemia of the central nervous system have examined either the brain or spinal cord, but not both. Spinal cord damage specifically after global ischemia has not been studied in detail. Because the exact nature of the neuronal damage to the spinal cord and the differences in neuronal damage between the brain and spinal cord after global ischemia are poorly understood, we developed a new global ischemia model in the rat and specifically studied spinal cord damage after global ischemia. Further, we compared the different forms of neuronal damage between the brain and spinal cord after global ischemia. Randomized, controlled study using three different global ischemia models in the rat. University research laboratory. Male, adult Sprague-Dawley rats (300 g). Animals were divided into three experimental groups, group A (n = 6, survived for 7 days), 12 mins of hemorrhagic shock; group B (n = 6, survived for 7 days), 5 mins of cardiac arrest; or group C (n = 6, each for 6 hrs, 12 hrs, 1 day, 3 days, and 7 days), 7 mins of hemorrhagic shock and 5 mins of cardiac arrest. Motor deficit of the hind limbs was studied 6 hrs to 7 days after resuscitation. Also, nonoperated animals (n = 6) were used as the control. Histologic analysis (hematoxylin and eosin, Fluoro-Jade B, terminal deoxynucleotidyl transferase- mediated dUTP end-labeling [TUNEL], Klüver-Barrera) and ultrastructural analysis using electron microscopy were performed on samples from the CA1 region of the hippocampus and lumbar spinal cord. Demyelination of the white matter of the lumbar spinal cord was analyzed semiquantitatively using Scion Image software. No paraplegic animals were observed in either group A or B. All group C animals showed severe hind-limb paralysis. Severe neuronal damage was found in the CA1 region of the hippocampus in all groups, and the state of delayed neuronal cell death was similar among the three groups. Neuronal damage in the lumbar spinal cord was detected only in group C animals, mainly in the dorsal horn and intermediate gray matter. Demyelination was prominent in the ventral and ventrolateral white matter in group C. A significant difference was observed between control and group C rats with Scion Image software. Ultrastructural analysis revealed extensive necrotic cell death in the intermediate gray matter in the lumbar spinal cord in group C rats. The combination in the global ischemia model (i.e., hemorrhagic shock followed by cardiac arrest) caused severe neuronal damage in the central nervous system. Thereby, hind-limb paralysis after global ischemia might result from spinal cord damage. These results suggest that therapeutic strategies for preventing spinal cord injury are necessary when treating patients with severe global ischemia.
    Full-text · Article · Dec 2006 · Critical Care Medicine
  • J. Ichikawa · Y. Hiraizumi · H. Miyaoka · T. Tachikawa
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    ABSTRACT: Thickening of the yellow ligament is clinically important as the main factor of backward compression in spinal canal stenosis and is known to be one of the main causes of lumbar spinal canal stenosis. Histologically, the ligament contains elastic fibers and a large amount of elastin that is a component of the fibers, and its metaplastic changes such as proliferation of collagen fibers and cartilaginous tissue occur with age. However, the molecular biological mechanism of such tissue changes has not been clarified in several respects. On the other hand, fibroblast growth factor (FGF) is known to stimulate growth of cells of mesodermal origin such as fibroblasts, vascular endothelial cells and epithelial cells. At present there are at least 23 species of FGF attracting attention. In the present study, we examined FGF-1 in the yellow ligament and comparatively examined the relation of the FGF-1 expression with lateral images of simple roentgenogram and MR images. The subjects were 11 patients who underwent operations for lumbar spinal canal stenosis, degenerative lumbar sliding and lumbar disk herniation. Sixteen extracted yellow ligament specimens were examined. At the time of operation, the patients were 24-79 years old or 65.7 years old on average and consisted of 6 males and 5 females. During extended fenestration or discectomy performed on lumbar spinal canal stenosis, degenerative lumbar sliding and lumbar disk herniation, specimens of yellow ligament tissue were collected and examined. After collection, each specimen was embedded in O.T.C compound and fixed by freezing. Thereafter, 4 μ m-thick sections were routinely prepared and stained with H-E and Alcian blue. In addition, immunostaining of FGF-1 was performed, and each tissue section was classified based on the number of FGF-1-positive cells. Images of the yellow ligament were classified according to the degree of osteophyte formation on simple roentgenogram lateral images, thickness of the yellow ligament and degree of stenosis of the spinal canal on MRI; furthermore, the relation to FGF-1 was examined. A high FGF-1 expression rate was found in the vertebral arch side where degeneration of yellow ligament was severe. The rate of FGF-1 expression rose with increasing thickness of the ligament on MR images. No clear relation to the degree of spinal canal stenosis or the degree of osteophyte formation was observed. In brief, FGF-1 was involved in degeneration of yellow ligament and showed a high correlation with changes in MR images.
    No preview · Article · Apr 2005
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    ABSTRACT: Anterior lumbar interbody fusion (ALIF), under laparoscope or retroperitoneoscope is a well accepted procedure for treatment of degenerative spinal abnormalities. Interbody fusion cages have been shown to promote good initial fixation in a variety of animal models, however few studies have examined the effects of the type of cage or direction of insertion on initial fixation strength. The present study biomechanically measured the initial fixation strength of ALIF using a threaded interbody fusion cage on fresh porcine spine. We performed two studies; Study 1 compared the effects of the number and the direction of insertion of cylindrical cages at the L4/5, 5/6 level on stiffness, and Study 2 investigated the effects of the type of cage and number using two types of cages (cylindrical and conical cages) at the L6/S1 level. In Study 1, there was significantly more stiffness with flexion in the single anterior group, the double anterior group, and the single anterolateral group compared to the control group (no cage insertion) . In addition, stiffness was significantly better in the single anterolateral group than in the single anterior group. There was no differentces between any of the groups in any loading mode. In Study 2, for extension, there was significantly better stiffness in the groups that received cylindrical or conical cages compared to no-insertion controls. In lateral bending, the two cylindrical cage groups had significantly better stiffness than controls. There were no differences in flexion and axial torsion between any of the groups. Again, there were no significant differences between any of the groups in any loading mode.
    Preview · Article · Jan 2004
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    ABSTRACT: We report the study of matrix metalloproteinases (MMPs) in cervical intervertebral discs, immunohistochemically, and by comparing the manifestation of MMPs with X ray-based side views and MRI visual imaging. We analyzed intervetebral disc tissue samples from 20 patients who had undergone surgery for herniation of their cervical intervertebral discs and cervical spondylosis-related myelosis. The patient age at surgery ranged from 22 to 68 years, with an average of 45.7 years. Eighteen of the patients were males and two were females. Immunostaining for MMPs was performed on frozen sections of the tissues to classify the samples based on the number of immunopositive cells. MMP levels in the resected tissues were also quantified by western blotting and densitometry. The concentrations were compared with the visual imaging of the discs. X ray-based side view images revealed a high ratio of MMPs, due to an increase in osteophytes. Further, when low intensities were observed by MRI, and also when the protrusion of intervertebral discs was substantial, MMP levels were considerable. Together, these results implicate MMPs in the metamorphosis of cervical intervertebral discs, and that the metamorphosis is strongly correlated with changes in MRI and X ray-based side view imaging.
    No preview · Article · Jan 2002