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Dive into the research topics where Hiroyuki Wakisaka is active.

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Featured researches published by Hiroyuki Wakisaka.


Otology & Neurotology | 2003

Efficacy of early treatment of Bell's palsy with oral acyclovir and prednisolone

Naohito Hato; Shuichi Matsumoto; Hisanobu Kisaki; Hirotaka Takahashi; Hiroyuki Wakisaka; Nobumitsu Honda; Kiyofumi Gyo; Shingo Murakami; Naoaki Yanagihara

Objective To investigate the therapeutic effects of acyclovir and prednisolone in relation to the timing of treatment in Bells palsy. Study Design This was a retrospective study of 480 Bells palsy patients who were treated with oral acyclovir and prednisolone (94 cases) or prednisolone alone (386 cases). Patients Patients met the after criteria: (1) severe or complete Bells palsy with a score lower than 20 on the 40-point Yanagihara facial score and (2) treatment started within 7 days after onset. The patients were treated with oral prednisolone (60–40 mg/day) with or without oral acyclovir (2,000 mg/day). Main Outcome Measure Rate of recovery, which was defined as a facial score of 36 or more, and the absence of contracture with synkinesis. Results The overall recovery rate of patients treated with acyclovir and prednisolone was 95.7 percent, which was better than that of patients treated with prednisolone alone (88.6%). The recovery rate in patients who began the combined therapy within 3 days of the onset of palsy was 100 percent and early treatment resulted in early remission. In contrast, the recovery rate in patients who started the combined therapy more than 4 days after onset was 86.2 percent. Conclusion These results suggest that early diagnosis and treatment within 3 days of the onset of paralysis are necessary for maximal efficacy of combined acyclovir and prednisolone therapy for Bells palsy.


Journal of Virology | 2006

Herpes simplex virus type 1 accumulation, envelopment, and exit in growth cones and varicosities in mid-distal regions of axons

Monica Miranda Saksena; Hiroyuki Wakisaka; Bibing Tijono; Ross A. Boadle; Frazer J. Rixon; Hirotaka Takahashi; Anthony L. Cunningham

ABSTRACT The mechanism of anterograde transport of alphaherpesviruses in axons remains controversial. This study examined the transport, assembly, and egress of herpes simplex virus type 1 (HSV-1) in mid- and distal axons of infected explanted human fetal dorsal root ganglia using confocal microscopy and transmission electron microscopy (TEM) at 19, 24, and 48 h postinfection (p.i.). Confocal-microscopy studies showed that although capsid (VP5) and tegument (UL37) proteins were not uniformly present in axons until 24 h p.i., they colocalized with envelope (gG) proteins in axonal varicosities and in growth cones at 24 and 48 h p.i. TEM of longitudinal sections of axons in situ showed enveloped and unenveloped capsids in the axonal varicosities and growth cones, whereas in the midregion of the axons, predominantly unenveloped capsids were observed. Partially enveloped capsids, apparently budding into vesicles, were observed in axonal varicosities and growth cones, but not during viral attachment and entry into axons. Tegument proteins (VP22) were found associated with vesicles in growth cones, either alone or together with envelope (gD) proteins, by transmission immunoelectron microscopy. Extracellular virions were observed adjacent to axonal varicosities and growth cones, with some virions observed in crescent-shaped invaginations of the axonal plasma membrane, suggesting exit at these sites. These findings suggest that varicosities and growth cones are probable sites of HSV-1 envelopment of at least a proportion of virions in the mid- to distal axon. Envelopment probably occurs by budding of capsids into vesicles with associated tegument and envelope proteins. Virions appear to exit from these sites by exocytosis.


Experimental Neurology | 1999

Effects of Basic Fibroblast Growth Factor (bFGF)-Neutralizing Antibody and Platelet Factor 4 on Facial Nerve Regeneration ☆

Yuh-Shyang Chen; Shingo Murakami; Kiyofumi Gyo; Hiroyuki Wakisaka; Seiji Matsuda; Masahiro Sakanaka

Exogenous basic fibroblast growth factor (bFGF) has been shown to prevent death of injured cholinergic neurons and stimulate neurite outgrowth from the proximal stump of the transected sciatic nerve. The present study was designed to examine the role of endogenous bFGF, rather than exogenous bFGF in the regenerative process of the transected facial nerve of guinea pig, by using the so-called silicone tubulization model which enabled us to bridge the transected facial nerve with a silicone tube and to inject into the tube bFGF-neutralizing antibody, normal IgG, saline, or platelet factor 4 (an antagonist for bFGF receptor). Under light microscopy, treatment with bFGF-neutralizing antibody caused significant decreases in vascular number, vascular area, and regenerating axons in the middle point of regeneration chambers at the third week after facial nerve transection, even though electron microscopy revealed that the bFGF-neutralizing antibody increased the number of thin axons with caliber smaller than 1 micrometer. Treatment with platelet factor 4 exhibited similar but more conspicuous effects on facial nerve regeneration. These findings suggest that endogenous bFGF not only facilitates angiogenesis within the transected facial nerve but also acts as a neurotrophic agent during facial nerve regeneration; it appears that endogenous bFGF contributes to the enlargement of axon caliber and increases the number of relatively large caliber axons.


Acta Oto-laryngologica | 2009

Basic fibroblast growth factor combined with biodegradable hydrogel promotes healing of facial nerve after compression injury: An experimental study

Hayato Komobuchi; Naohito Hato; Masato Teraoka; Hiroyuki Wakisaka; Hirotaka Takahashi; Kiyofumi Gyo; Yasuhiko Tabata; Masaya Yamamoto

Conclusion. Topical application of basic fibroblast growth factor (bFGF) hydrogel facilitates faster healing from traumatic facial paralysis due to continuous release of bFGF. Objectives. bFGF is considered a potent agent to facilitate recovery from neuronal damage; however, exogenously applied bFGF does not work well because of its short acting time. To enhance the effects in vivo, we developed a new drug delivery system by embedding bFGF in a gelatin hydrogel that degrades slowly. In this study, the effects of bFGF-hydrogel on traumatic facial nerve paralysis were investigated in guinea pigs. Methods. The intratemporal facial nerve was exposed and clamped at the vertical portion using micro needle forceps. The animals were then subjected to one of the following three procedures: group A, no further treatment; group B, one-shot application of bFGF to the nerve; and group C, application of bFGF-hydrogel instead. Six weeks later, facial nerve functions were evaluated by three test batteries: observation of facial movements, electrophysiological testing, and histological study. Results. The results for groups A and B were similar in the three tests, indicating that one-shot application of bFGF did not benefit facial nerve recovery. In contrast, group C achieved better results in all tests.


Anatomy and Embryology | 2003

Lectin histochemical study on the olfactory organ of the newt, Cynops pyrrhogaster , revealed heterogeneous mucous environments in a single nasal cavity

Shouichiro Saito; Toshiyasu Matsui; Naoto Kobayashi; Hiroyuki Wakisaka; Katsumi Mominoki; Seiji Matsuda; Kazuyuki Taniguchi

Expression patterns of glycoconjugates were examined by lectin histochemistry in the nasal cavity of the Japanese red-bellied newt, Cynops pyrrhogaster. Its nasal cavity consisted of two components, a flattened chamber, which was the main nasal chamber (MNC), and a lateral diverticulum called the lateral nasal sinus (LNS), which communicated medially with the MNC. The MNC was lined with the olfactory epithelium (OE), while the diverticulum constituting the LNS was lined with the vomeronasal epithelium (VNE). Nasal glands were observed beneath the OE but not beneath the VNE. In addition, a secretory epithelium was revealed on the dorsal boundary between the MNC and the LNS, which we refer to as the boundary secretory epithelium (BSE) in this study. The BSE seemed to play an important role in the construction of the mucous composition of the VNE. Among 21 lectins used in this study, DBA, SBA and Jacalin showed different staining patterns between the OE and the VNE. DBA staining showed remarkable differences between the OE and the VNE; there was intense staining in the free border and the supporting cells of the VNE, whereas there was no staining or weak staining in the cells of the OE. SBA and Jacalin showed different stainings in the receptor neurons for the OE and the VNE. Furthermore, UEA-I and Con A showed different stainings for the nasal glands. UEA-I showed intense staining in the BSE and in the nasal glands located in the ventral wall of the MNC (VNG), whereas Con A showed intense staining in the BSE and in the nasal glands located in the dorsal and medial wall of the MNC (DMNG). The DMNG were observed to send their excretory ducts into the OE, whereas no excretory ducts were observed from the VNG to the OE or the VNE. These results suggested that the secretion by the supporting cells as well as the BSE and the DMNG establishes that there are heterogeneous mucous environments in the OE and the VNE, although both epithelia are situated in the same nasal cavity.


Annals of Otology, Rhinology, and Laryngology | 2002

Pathophysiology of Facial Nerve Paralysis Induced by Herpes Simplex Virus Type 1 Infection

Naohito Hato; Hisanobu Kisaki; Nobumitu Honda; Hirotaka Takahashi; Shingo Murakami; Hiroyuki Wakisaka; Kiyofumi Gyo

Herpes simplex virus type 1 (HSV-1) has been proven to be a cause of Bells palsy; however, the underlying pathophysiology of the facial nerve paralysis is not fully understood. We established a mouse model with facial nerve paralysis induced by HSV-1 infection simulating Bells palsy and investigated the pathophysiology of the facial nerve paralysis. The time course of the R1 latency in the blink reflex tests paralleled the recovery of the facial nerve paralysis well, whereas electroneurographic recovery tended to be delayed, compared to that of the paralysis; these responses are usually seen in Bells palsy. On histopathologic analysis, intact, demyelinated, and degenerated nerves were intermingled in the facial nerve in the model. The similarity of the time course of facial nerve paralysis and the electrophysiological results in Bells palsy and the model strongly suggest that the pathophysiological basis of Bells palsy is a mixed lesion of various nerve injuries.


Cellular & Molecular Biology Letters | 2011

Rho kinase inhibitors stimulate the migration of human cultured osteoblastic cells by regulating actomyosin activity.

Xuejiao Zhang; Cheng Li; Huiling Gao; Hiroaki Nabeka; Tetsuya Shimokawa; Hiroyuki Wakisaka; Seiji Matsuda; Naoto Kobayashi

We investigated the effects of Rho-associated kinase (ROCK) on migration and cytoskeletal organization in primary human osteoblasts and Saos-2 human osteosarcoma cells. Both cell types were exposed to two different ROCK inhibitors, Y-27632 and HA-1077. In the improved motility assay used in the present study, Y-27632 and HA-1077 significantly increased the migration of both osteoblasts and osteosarcoma cells on plastic in a dose-dependent and reversible manner. Fluorescent images showed that cells of both types cultured with Y-27632 or HA-1077 exhibited a stellate appearance, with poor assembly of stress fibers and focal contacts. Western blotting showed that ROCK inhibitors reduced myosin light chain (MLC) phosphorylation within 5 min without affecting overall myosin light-chain protein levels. Inhibition of ROCK activity is thought to enhance the migration of human osteoblasts through reorganization of the actin cytoskeleton and regulation of myosin activity. ROCK inhibitors may be potentially useful as anabolic agents to enhance the biocompatibility of bone and joint prostheses.


Experimental Neurology | 2002

Demyelination Associated with HSV-1-Induced Facial Paralysis

Hiroyuki Wakisaka; Naohito Hato; Nobumitsu Honda; Hirotaka Takahashi; Hisanobu Kisaki; Shingo Murakami; Kiyofumi Gyo; Katsumi Mominoki; Naoto Kobayashi; Seiji Matsuda

In 1995, we developed an animal model of transient homolateral facial nerve paralysis by inoculating Herpes simplex virus type 1 (HSV-1) into the auricle of mice. This study examined the mechanism of facial nerve paralysis in this model histopathologically. Using the immunofluorescence technique with anti-HSV-1 antibody, the time course of viral spread and the site of viral replication were investigated over the entire course of the facial nerve. Furthermore, viral replication and nerve degeneration at the site of viral replication were observed by electron microscopy. On the 7th day after inoculation, facial paralysis was observed in more than 60% of mice. Immunofluorescence study revealed HSV-1 in the geniculate ganglion, the descending root, and the facial nucleus at this stage. On the 9th day, the descending root in the sections stained with osmium looked pale, because prominent demyelination had occurred in this region; electron micrographs showed many degenerated oligodendrocytes and large naked axons. In contrast, the facial nucleus neurons showed no remarkable degeneration, despite HSV-1 particles in their cytoplasm. From these findings, we concluded that facial nerve paralysis in this model is caused mainly by facial nerve demyelination in the descending root.


Oral Oncology | 2012

One-step nucleic acid amplification for detecting lymph node metastasis of head and neck squamous cell carcinoma.

Hiroyuki Goda; Koh-ichi Nakashiro; Ryota Oka; Hiroshi Tanaka; Hiroyuki Wakisaka; Naohito Hato; Masamitsu Hyodo; Hiroyuki Hamakawa

OBJECTIVES Lymph node stage is an important prognostic factor in head and neck squamous cell carcinoma (HNSCC). We previously reported the clinical usefulness of sentinel lymph node biopsy diagnosed by genetic analysis using quantitative RT-PCR. However, this method takes about 3h. In this study, we attempted to develop a more efficient method for the intraoperative genetic detection of lymph node metastasis in HNSCC. MATERIALS AND METHODS A total of 312 lymph nodes (65 patients) were diagnosed by the one-step nucleic acid amplification (OSNA) method using GD-100. OSNA consists of a short homogenization step followed by amplification of cytokeratin 19 (CK19) mRNA directly from the lysate. Each lymph node was divided into two to diagnose metastasis. One half was used for the OSNA assay, and the other was subjected to semi-serial sectioning, sliced at 200-μm intervals and examined by H&E and cytokeratin AE1/AE3 immunohistochemical staining. The accuracy of OSNA assay was evaluated based on histopathological diagnosis. RESULTS Sixty-one of 312 lymph nodes were pathologically metastasis-positive. The overall concordance rate between the OSNA assay using breast cancer criteria and histopathology was 94.2%. The optimal cut-off for the copy number of CK19 mRNA in assessing lymph node metastasis of HNSCC was 300 copies/μl, which had the highest diagnostic accuracy (95.2%). The OSNA assay can be completed within 30 min. CONCLUSION The OSNA assay, which shows high sensitivity and specificity, suggests the possibility to be used as a novel tool for the genetic detection of lymph node metastasis in HNSCC patients.


The Journal of Comparative Neurology | 2005

Phylogenetic investigation of Dogiel's pericellular nests and Cajal's initial glomeruli in the dorsal root ganglion

Seiji Matsuda; Naoto Kobayashi; Takehiro Terashita; Tetsuya Shimokawa; Kazuhiro Shigemoto; Katsumi Mominoki; Hiroyuki Wakisaka; Shouichiro Saito; Kyoujy Miyawaki; Kyoko Saito; Fumiki Kushihata; Jie Chen; Shuang-yan Gao; Chun-yu Li; Min Wang; Takashi Fujiwara

Cajals initial glomeruli (IG) and Dogiels pericellular nests (PCNs) were first described from methylene blue preparations of healthy animal tissues around the beginning of the last century. Since that time, although many reports have been published concerning these structures, few have focused on their development and phylogeny in healthy animals. The aim of this study was to examine the phylogenetic development of the sensory neurons in Cajals IG (also called axonal glomeruli) and Dogiels PCNs in the dorsal root ganglion (DRG) of the healthy adult frog, chick, rat, and rabbit. The three‐dimensional architecture of the neurons was observed in ganglia by scanning electron microscopy after removal of the connective tissue. The neurons in the DRG of fish are known to be bipolar, but DRG neurons in the species examined here were found to be pseudounipolar, with single stem processes. The proportion of neurons having IG or PCNs increased with increasing phylogenetic complexity in the species examined here. Cajals initial glomeruli, the convolution of the stem process near the parent cell body: In frogs, the ganglia were small and the neuronal stem processes were very short and straight. In chicks, the stem processes were longer; sometimes very long, tortuous processes were observed. However, no neurons with typical IG were observed in either species. Typical IG were observed in rats and rabbits; their occurrence was much more frequent in rabbits. Pseudounipolarization, i.e., the transition from bipolar to pseudounipolar neurons, is thought to save space, limit the length of neuronal processes, and reduce conduction time. However, an explanation of the evolutionary advantage of the IG, which is formed by the excessive prolongation of the stem process, remains elusive. The cytological and electrophysiological importance of IG has been discussed. Dogiels pericellular nests (PCNs), which resemble balls of yarn made of thin unmyelinated nerve fibers around DRG neurons, have been observed in the DRG of rats and rabbits, but not in frogs or chicks. This interesting structure shows not only ontogenetic development in healthy animals but also phylogenetic development among species. The nerve fibers in the PCNs were less than 1.2 μm in diameter and had some varicosities. An immunohistochemical study using anti‐tyrosine hydroxylase (TH) antibody revealed that some PCNs contain TH‐positive nerve fibers and varicosities. Such TH‐positive PCNs disappear after sympathectomy. These results suggest that the PCNs are made up of autonomic nerve fibers. J. Comp. Neurol. 491:234–245, 2005.

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