Susumu Shirabe - Academia.edu (original) (raw)
Papers by Susumu Shirabe
Igaku Kyoiku / Medical Education (Japan), 2015
Title A Single-Nucleotide Polymorphism of PARK2 Affects the Phenotype in Sporadic Parkinson Disea... more Title A Single-Nucleotide Polymorphism of PARK2 Affects the Phenotype in Sporadic Parkinson Disease Author(s) Sakai, Muniko; Tsujino, Akira; Eguchi, Hiroto; Sato, Katsuya; Shirabe, Susumu; Tateishi, Yohei; Sato, Akira; Tsujihata, Mitsuhiro; Yoshimura, Toshiro; Eguchi, Katsumi Citation Acta medica Nagasakiensia, 54(3), pp.67-71 ; 2010 Issue Date 2010-03 URL http://hdl.handle.net/10069/23120 Right NAOSITE: Nagasaki University's Academic Output SITE
Journal of the Neurological Sciences, 2017
Patients and Methods / Material and Methods: Self-identified EVD survivors (n =164) and close con... more Patients and Methods / Material and Methods: Self-identified EVD survivors (n =164) and close contacts of survivors (n= 92) enrolled in the PREVAIL III EVD natural history study underwent detailed neurological evaluations. Neurologic examination and neurologic symptoms during and after EVD were documented with a standardized assessment at the 6-month study visit. The cohort underwent follow-up assessment at the 12-month study visit. Based on disparate serology testing, 11 self-identified survivors and 11 selfidentified close contacts were excluded from analysis.
Journal of clinical microbiology, 1995
Human T-cell lymphotropic virus type 1 (HTLV-1) is known to be transmitted vertically through bre... more Human T-cell lymphotropic virus type 1 (HTLV-1) is known to be transmitted vertically through breastfeeding and horizontally by blood transfusion and sexual contact. Our intervention study has suggested the presence of additional alternative maternal transmission pathways. To explore the possibility of transmission through saliva, we used PCR to quantify the HTLV-1 provirus in saliva samples from 18 carrier mothers and 10 patients with HTLV-1-associated myelopathy/tropical spastic paraparesis. The provirus was detected in 60 and 90%, respectively, of the samples, with estimated copy numbers in the range of 10 to 10(4)/ml. However, the saliva, regardless of the presence or absence of antibodies to the virus, showed a strong tendency to inhibit the cell-to-cell transmission of HTLV-1 in vitro, as examined by a syncytium inhibition assay. The natural inhibitory activity in saliva of seronegative volunteers was heat sensitive, and most of the activity was recovered by ultrafiltration in...
Medicine, 2018
In industrialized countries, the turnover rate of preschool workers is extremely high and now rep... more In industrialized countries, the turnover rate of preschool workers is extremely high and now represents a social problem. Consequently, it has become important to promote stable early care and educational environments for this population. Several factors related to working environments are known to affect turnover intention; however, the specific factors related to turnover intention among preschool workers have not yet been identified. Considering this, the objective of the present study was to determine factors associated with preschool workers' willingness to continue working. The participants of this study were 1137 preschool workers based in Nagasaki Prefecture, Japan. Multivariate logistic regression analysis was used to analyze the participants' data, with willingness to continue working for 5 years or more set as the dependent variable. Analysis of the results for all subjects clearly showed that male sex, older age, good mental health, high number of social supports, and good work engagement have a positive effect on willingness to continue working. Further, stratifying the participants in terms of age revealed that for preschool workers under 39 years, male sex, good mental health, high number of social supports, and good work engagement act positively in regard to willingness to continue working. Meanwhile, for those over 40 years, it was found that permanent employment and good work engagement act positively in this regard. Thus, work engagement was the only common factor between preschool workers under 39 and over 40. The findings of this cross-sectional study demonstrate that the factors associated with willingness to continue working among preschool workers differ between younger and older professionals. These findings underline the importance of considering age categories when attempting to maximize such professionals' willingness to continue working.
PloS one, 2016
Helicobacter pylori (HP) infection is implicated in gastric and extra-gastric diseases. While gas... more Helicobacter pylori (HP) infection is implicated in gastric and extra-gastric diseases. While gastritis-related chronic inflammation represents a known trigger of metabolic disturbances, whether metabolic syndrome (MetS) is affected by gastritis status remains unclear. We aimed to clarify the effect of HP-related gastritis on the risk of MetS. We retrospectively enrolled patients undergoing screening for MetS between 2014 and 2015. Investigations included HP-specific immunoglobulin G (IgG) antibody assays to detect HP infection, and serum pepsinogen assays to evaluate atrophic gastritis status. The risk of MetS was evaluated via multiple logistic regression analyses with two covariates: serum HP infection status (IgG levels) and atrophic gastritis status (two criteria were applied; pepsinogen I/II ratio < 3 or both pepsinogen I levels ≤ 70 μg/L and pepsinogen I/II ratio < 3). Of 1,044 participants, 247 (23.7%) were HP seropositive, and 62 (6.0%) had MetS. HP seronegative and s...
BMJ open, 2012
Objectives To assess the utility of the display standardisation of diffusion-weighted MRI (DWI) a... more Objectives To assess the utility of the display standardisation of diffusion-weighted MRI (DWI) and to compare the effectiveness of DWI and fluid-attenuated inversion recovery (FLAIR) MRI for the diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD). Design A reliability and agreement study. Setting Thirteen MRI observers comprising eight neurologists and five radiologists at two universities in Japan. Participants Data of 1.5-Tesla DWI and FLAIR were obtained from 29 patients with sCJD and 13 controls. Outcome measures Standardisation of DWI display was performed utilising b0 imaging. The observers participated in standardised DWI, variable DWI (the display adjustment was observer dependent) and FLAIR sessions. The observers independently assessed each MRI for CJD-related lesions, that is, hyperintensity in the cerebral cortex or striatum, using a continuous rating scale. Performance was evaluated by the area under the receiver operating characteristics curve (AUC). Results The me...
![Research paper thumbnail of [A case of Creutzfeldt-Jakob disease with a point mutation of prion protein at codon 180]](https://attachments.academia-assets.com/87108836/thumbnails/1.jpg)
](Nō to shinkei = Brain and nerve, 2004
A 67-year-old woman was admitted to our hospital with progressive aphasia. There was no family hi... more A 67-year-old woman was admitted to our hospital with progressive aphasia. There was no family history of similar diseases or any history of dura transplantation. Cranial magnetic resonance imaging (MRI) showed high signal areas in the temporal and parietal cortex predominantly on the left side on both T2-weighted images and on diffusion-weighted images. There were no periodic synchronous discharges observed on the electroencephalogram. As prion protein gene codon 180 point mutation (Val/Ile) was detected, we diagnosed her as having Creutzfeldt-Jakob disease (CJD). The characteristics of CJD of this type differ from those of sporadic CJD. To date, few papers on CJD with point mutation of codon 180 have been reported from Japan.
Proceedings of the National Academy of Sciences, 2007
Prion proteins are key molecules in transmissible spongiform encephalopathies (TSEs), but the pre... more Prion proteins are key molecules in transmissible spongiform encephalopathies (TSEs), but the precise mechanism of the conversion from the cellular form (PrP C ) to the scrapie form (PrP Sc ) is still unknown. Here we discovered a chemical chaperone to stabilize the PrP C conformation and identified the hot spots to stop the pathogenic conversion. We conducted in silico screening to find compounds that fitted into a “pocket” created by residues undergoing the conformational rearrangements between the native and the sparsely populated high-energy states (PrP*) and that directly bind to those residues. Forty-four selected compounds were tested in a TSE-infected cell culture model, among which one, 2-pyrrolidin-1-yl- N -[4-[4-(2-pyrrolidin-1-yl-acetylamino)-benzyl]-phenyl]-acetamide, termed GN8, efficiently reduced PrP Sc . Subsequently, administration of GN8 was found to prolong the survival of TSE-infected mice. Heteronuclear NMR and computer simulation showed that the specific bindi...
Neuroscience Letters, 2011
Myotonia congenita is caused by mutation of the CLCN1 gene, which encodes the human skeletal musc... more Myotonia congenita is caused by mutation of the CLCN1 gene, which encodes the human skeletal muscle chloride channel (ClC-1). The ClC-1 protein is a dimer comprised of two identical subunits each incorporating its own separate pore. However, the precise pathophysiological mechanism underlying the abnormal ClC-1 channel gating in some mutants is not fully understood. We characterized a ClC-1 mutation, Pro-480-Thr (P480T) identified in dominant myotonia congenita, by using whole-cell recording. P480T ClC-1 revealed significantly slowed activation kinetics and a slight depolarizing shift in the voltage-dependence of the channel gating. Wild-type/mutant heterodimers exhibited similar kinetic properties and voltage-dependency to mutant homodimers. Simulating myotonic discharge with the voltage clamp protocol of a 50 Hz train pulse, the increment of chloride conductance was impaired in both wild-type/mutant heterodimers and mutant homodimers, clearly indicating a dominant-negative effect. Our data showed that slow activation gating of P480T ClC-1 impaired the increment of chloride conductance during repetitive depolarization, thereby accentuating the chloride conductance reduction caused by a slight depolarizing shift in the voltage-dependence of the channel gating. This pathophysiology may explain the clinical features of myotonia congenita.
Nature Medicine, 2011
The development of technologies for the in vitro amplification of the abnormal conformers of prio... more The development of technologies for the in vitro amplification of the abnormal conformers of prion protein (PrP Sc) has generated the potential for a novel diagnostic assay for prion disease. Previously, we developed a new PrP Sc amplification assay designated quaking-induced conversion (QUIC), which involves intermittent, automated shaking of the substrate, soluble recombinant PrP. We further improved the rapidity and practicality of this method by combining it with thioflavin T fluorescence to monitor the amyloid fibril formation. This assay, termed "real-time QUIC (RT-QUIC)", allows within 48 h, the detection of ≥1 fg of PrP Sc in diluted Creutzfeldt-Jakob disease (CJD) brain homogenate. Moreover, we assessed the technique first in a series of Japanese subjects, and then in a blind study of 30 cerebrospinal fluid specimens from Australia, which achieved greater than 80% sensitivity and 100% specificity. These findings indicate the promising enhanced diagnostic capacity of RT-QUIC in the ante-mortem evaluation of suspected CJD.
Laboratory Investigation, 2010
Periodic sharp wave complexes observed on an electroencephalographic recording and the presence o... more Periodic sharp wave complexes observed on an electroencephalographic recording and the presence of a 14-3-3 protein in the cerebrospinal fluid (CSF) are both included in the diagnostic criteria for the Creutzfeldt-Jakob disease (CJD) supplied by the World Health Organization; however, the presence or absence of the 14-3-3 protein in the CSF is sometimes difficult to discern on a western blot because of equivocal bands. The goal of this study was to establish a standard 14-3-3 protein assay and to determine the threshold level of a 14-3-3 protein that can be assayed by western blot. We searched for the most suitable isoform of the 14-3-3 protein to test for in protein assays, and the most sensitive antibody among four antibodies with an affinity for 14-3-3. We measured the levels of all 14-3-3 isoforms in 112 patients with CJD and in 100 patients with other diseases. We compared the performances of four different antibodies. We carried out a semi-quantitative analysis of g-isoform levels using the LAS 3000 system, which was capable of producing a digital image from the luminescence on a western blot. We determined that the most suitable isoform of the 14-3-3 protein for conducting a standardized assay was the g-isoform. Among the four commercially available antibodies for this protein, the most sensitive and specific was 18647 (IBL, Japan). We report the high repeatability of the detection of the 14-3-3 protein by this antibody to the g-isoform, showing that western blot can be used for semi-quantitative analysis.
Journal of the Neurological Sciences, 1987
The motor end-plate fine structure was studied in 3 patients with type A botulism and compared wi... more The motor end-plate fine structure was studied in 3 patients with type A botulism and compared with that in 4 patients with Lambert-Eaton myasthenic syndrome (LES). In the botulism cases a biopsy of the biceps brachii muscle was performed at the chronic stage. The skeletal muscle showed a neurogenic change. The nerve terminal area had decreased and the postsynaptic regions had been denuded of their nerve terminals in 16% of the regions (9.8% in control). No highly simplified postsynaptic regions were observed. The findings are consistent with those observed at the motor end-plates in motoneuron diseases. By contrast, in LES no changes were observed in the presynaptic region. In the postsynaptic region, the postsynaptic membrane length and membrane density decreased and hypertrophy of the junctional folds was not observed.
Journal of the Neurological Sciences, 2002
We previously reported elevated levels of serum interleukin-12 (IL-12) in association with increa... more We previously reported elevated levels of serum interleukin-12 (IL-12) in association with increased interferon-g (IFN-g) levels in patients with human T-lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The interaction between IL-12 and IL-12 receptor (IL-12R) plays an important role in differentiation of the T helper type 1 (Th1) phenotype. In this study, we further examined the IL-12/IL-12R axis by investigating the expression of IL-12R and CD40 ligand (CD40L) in peripheral blood mononuclear cells (PBMC) of 18 HAM/TSP patients, and comparing the levels with those in 25 patients with other neurological disorders, including 4 anti-HTLV-I-seropositive carriers as controls. Two-color analysis by flow cytometry revealed a significantly high percentage of IL-12R h1 + cells in CD4 + T lymphocytes in HAM/TSP patients compared to the control. Furthermore, IL-12R h2 mRNA expression in PBMC was detected by reverse-transcriptase polymerase chain reaction in 6 of 18 HAM/TSP patients, but not in any control patients. In contrast, there was no significant difference between the percentage of CD40L + cells in CD4 + T lymphocytes in HAM/TSP and control patients. Our results suggest Th1 immune activation in patients with HAM/TSP, which leads to chronic inflammation in the spinal cord, mediated by dysregulation of the IL-12/IL-12R axis rather than of the CD40/CD40L interaction.
Journal of the Neurological Sciences, 1998
We report a 73-year-old man with human T-lymphotropic virus type I (HTLV-I)-associated myelopathy... more We report a 73-year-old man with human T-lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM) complicated witḧ multi-organ inflammatory disease, including Sjogren's syndrome, interstitial cystitis, and uveitis. The presence of HTLV-I proviral DNA in peripheral blood mononuclear cells (PBMC), cerebrospinal fluid, salivary gland, mucosa of urinary bladder, and aqueous humor was confirmed by polymerase chain reaction using HTLV-I pX region primer. Western blot analysis revealed the presence of anti-HTLV-I antibodies in serum, CSF, saliva, and urine, suggesting replication of HTLV-I in each tissue. A high load of HTLV-I proviral DNA (20 copies out of 100 PBMC) was present, associated with increased spontaneous proliferation of peripheral blood lymphocytes (24 747 cpm). Our results suggest that the high load of HTLV-I in patients with HAM may potentially induce systemic inflammation in several organs.
Journal of the Neurological Sciences, 1998
We compared soluble E-selectin (sE-selectin) and L-selectin (sL-selectin) levels in sera and cere... more We compared soluble E-selectin (sE-selectin) and L-selectin (sL-selectin) levels in sera and cerebrospinal fluid (CSF) of 30 patients with human T-lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM), with those of 10 patients with the relapsing-remitting form of multiple sclerosis (MS), and 16 patients with other neurological diseases (OND). Serum levels of both sE-selectin and sL-selectin, as measured by enzyme-linked immunosorbent assay, were significantly elevated in patients with HAM, compared to patients with OND. In addition, serum levels of sL-selectin were significantly elevated in HAM patients compared to MS patients. No significant difference was found in CSF levels of sL-selectin between HAM patients and controls. However, HAM patients who had received blood transfusions had significantly higher CSF levels of sL-selectin than HAM patients without a past history of transfusions, suggesting that HAM patients with past history of transfusion have a more active immunological state in the central nervous system. sE-selectin was not detected in CSF of HAM patients and controls. This finding might be based on exaggerated inflammatory conditions following increased attachment of lymphocytes to activated endothelial cells in HAM patients.
Journal of Neuroimmunology, 1998
Using a 51Cr release assay, we investigated Fas-mediated cytotoxicity of peripheral blood CD4+ T ... more Using a 51Cr release assay, we investigated Fas-mediated cytotoxicity of peripheral blood CD4+ T cells of patients with human T-lymphotropic virus type-I (HTLV-I)-associated myelopathy (HAM) against T98G, a glioblastoma cell line which expresses Fas. Cytotoxic activity of CD4+ T cells against T98G was significantly higher in HAM patients than in controls. Moreover, when CD4+ T cells of HAM patients were preincubated with a monoclonal antibody to human Fas ligand (FasL), cytotoxic activity against T98G was significantly suppressed. These results suggest that damage to nervous tissues by the Fas/FasL system is involved in the pathogenesis of HAM.
Igaku Kyoiku / Medical Education (Japan), 2015
Title A Single-Nucleotide Polymorphism of PARK2 Affects the Phenotype in Sporadic Parkinson Disea... more Title A Single-Nucleotide Polymorphism of PARK2 Affects the Phenotype in Sporadic Parkinson Disease Author(s) Sakai, Muniko; Tsujino, Akira; Eguchi, Hiroto; Sato, Katsuya; Shirabe, Susumu; Tateishi, Yohei; Sato, Akira; Tsujihata, Mitsuhiro; Yoshimura, Toshiro; Eguchi, Katsumi Citation Acta medica Nagasakiensia, 54(3), pp.67-71 ; 2010 Issue Date 2010-03 URL http://hdl.handle.net/10069/23120 Right NAOSITE: Nagasaki University's Academic Output SITE
Journal of the Neurological Sciences, 2017
Patients and Methods / Material and Methods: Self-identified EVD survivors (n =164) and close con... more Patients and Methods / Material and Methods: Self-identified EVD survivors (n =164) and close contacts of survivors (n= 92) enrolled in the PREVAIL III EVD natural history study underwent detailed neurological evaluations. Neurologic examination and neurologic symptoms during and after EVD were documented with a standardized assessment at the 6-month study visit. The cohort underwent follow-up assessment at the 12-month study visit. Based on disparate serology testing, 11 self-identified survivors and 11 selfidentified close contacts were excluded from analysis.
Journal of clinical microbiology, 1995
Human T-cell lymphotropic virus type 1 (HTLV-1) is known to be transmitted vertically through bre... more Human T-cell lymphotropic virus type 1 (HTLV-1) is known to be transmitted vertically through breastfeeding and horizontally by blood transfusion and sexual contact. Our intervention study has suggested the presence of additional alternative maternal transmission pathways. To explore the possibility of transmission through saliva, we used PCR to quantify the HTLV-1 provirus in saliva samples from 18 carrier mothers and 10 patients with HTLV-1-associated myelopathy/tropical spastic paraparesis. The provirus was detected in 60 and 90%, respectively, of the samples, with estimated copy numbers in the range of 10 to 10(4)/ml. However, the saliva, regardless of the presence or absence of antibodies to the virus, showed a strong tendency to inhibit the cell-to-cell transmission of HTLV-1 in vitro, as examined by a syncytium inhibition assay. The natural inhibitory activity in saliva of seronegative volunteers was heat sensitive, and most of the activity was recovered by ultrafiltration in...
Medicine, 2018
In industrialized countries, the turnover rate of preschool workers is extremely high and now rep... more In industrialized countries, the turnover rate of preschool workers is extremely high and now represents a social problem. Consequently, it has become important to promote stable early care and educational environments for this population. Several factors related to working environments are known to affect turnover intention; however, the specific factors related to turnover intention among preschool workers have not yet been identified. Considering this, the objective of the present study was to determine factors associated with preschool workers' willingness to continue working. The participants of this study were 1137 preschool workers based in Nagasaki Prefecture, Japan. Multivariate logistic regression analysis was used to analyze the participants' data, with willingness to continue working for 5 years or more set as the dependent variable. Analysis of the results for all subjects clearly showed that male sex, older age, good mental health, high number of social supports, and good work engagement have a positive effect on willingness to continue working. Further, stratifying the participants in terms of age revealed that for preschool workers under 39 years, male sex, good mental health, high number of social supports, and good work engagement act positively in regard to willingness to continue working. Meanwhile, for those over 40 years, it was found that permanent employment and good work engagement act positively in this regard. Thus, work engagement was the only common factor between preschool workers under 39 and over 40. The findings of this cross-sectional study demonstrate that the factors associated with willingness to continue working among preschool workers differ between younger and older professionals. These findings underline the importance of considering age categories when attempting to maximize such professionals' willingness to continue working.
PloS one, 2016
Helicobacter pylori (HP) infection is implicated in gastric and extra-gastric diseases. While gas... more Helicobacter pylori (HP) infection is implicated in gastric and extra-gastric diseases. While gastritis-related chronic inflammation represents a known trigger of metabolic disturbances, whether metabolic syndrome (MetS) is affected by gastritis status remains unclear. We aimed to clarify the effect of HP-related gastritis on the risk of MetS. We retrospectively enrolled patients undergoing screening for MetS between 2014 and 2015. Investigations included HP-specific immunoglobulin G (IgG) antibody assays to detect HP infection, and serum pepsinogen assays to evaluate atrophic gastritis status. The risk of MetS was evaluated via multiple logistic regression analyses with two covariates: serum HP infection status (IgG levels) and atrophic gastritis status (two criteria were applied; pepsinogen I/II ratio < 3 or both pepsinogen I levels ≤ 70 μg/L and pepsinogen I/II ratio < 3). Of 1,044 participants, 247 (23.7%) were HP seropositive, and 62 (6.0%) had MetS. HP seronegative and s...
BMJ open, 2012
Objectives To assess the utility of the display standardisation of diffusion-weighted MRI (DWI) a... more Objectives To assess the utility of the display standardisation of diffusion-weighted MRI (DWI) and to compare the effectiveness of DWI and fluid-attenuated inversion recovery (FLAIR) MRI for the diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD). Design A reliability and agreement study. Setting Thirteen MRI observers comprising eight neurologists and five radiologists at two universities in Japan. Participants Data of 1.5-Tesla DWI and FLAIR were obtained from 29 patients with sCJD and 13 controls. Outcome measures Standardisation of DWI display was performed utilising b0 imaging. The observers participated in standardised DWI, variable DWI (the display adjustment was observer dependent) and FLAIR sessions. The observers independently assessed each MRI for CJD-related lesions, that is, hyperintensity in the cerebral cortex or striatum, using a continuous rating scale. Performance was evaluated by the area under the receiver operating characteristics curve (AUC). Results The me...
Nō to shinkei = Brain and nerve, 2004
A 67-year-old woman was admitted to our hospital with progressive aphasia. There was no family hi... more A 67-year-old woman was admitted to our hospital with progressive aphasia. There was no family history of similar diseases or any history of dura transplantation. Cranial magnetic resonance imaging (MRI) showed high signal areas in the temporal and parietal cortex predominantly on the left side on both T2-weighted images and on diffusion-weighted images. There were no periodic synchronous discharges observed on the electroencephalogram. As prion protein gene codon 180 point mutation (Val/Ile) was detected, we diagnosed her as having Creutzfeldt-Jakob disease (CJD). The characteristics of CJD of this type differ from those of sporadic CJD. To date, few papers on CJD with point mutation of codon 180 have been reported from Japan.
Proceedings of the National Academy of Sciences, 2007
Prion proteins are key molecules in transmissible spongiform encephalopathies (TSEs), but the pre... more Prion proteins are key molecules in transmissible spongiform encephalopathies (TSEs), but the precise mechanism of the conversion from the cellular form (PrP C ) to the scrapie form (PrP Sc ) is still unknown. Here we discovered a chemical chaperone to stabilize the PrP C conformation and identified the hot spots to stop the pathogenic conversion. We conducted in silico screening to find compounds that fitted into a “pocket” created by residues undergoing the conformational rearrangements between the native and the sparsely populated high-energy states (PrP*) and that directly bind to those residues. Forty-four selected compounds were tested in a TSE-infected cell culture model, among which one, 2-pyrrolidin-1-yl- N -[4-[4-(2-pyrrolidin-1-yl-acetylamino)-benzyl]-phenyl]-acetamide, termed GN8, efficiently reduced PrP Sc . Subsequently, administration of GN8 was found to prolong the survival of TSE-infected mice. Heteronuclear NMR and computer simulation showed that the specific bindi...
Neuroscience Letters, 2011
Myotonia congenita is caused by mutation of the CLCN1 gene, which encodes the human skeletal musc... more Myotonia congenita is caused by mutation of the CLCN1 gene, which encodes the human skeletal muscle chloride channel (ClC-1). The ClC-1 protein is a dimer comprised of two identical subunits each incorporating its own separate pore. However, the precise pathophysiological mechanism underlying the abnormal ClC-1 channel gating in some mutants is not fully understood. We characterized a ClC-1 mutation, Pro-480-Thr (P480T) identified in dominant myotonia congenita, by using whole-cell recording. P480T ClC-1 revealed significantly slowed activation kinetics and a slight depolarizing shift in the voltage-dependence of the channel gating. Wild-type/mutant heterodimers exhibited similar kinetic properties and voltage-dependency to mutant homodimers. Simulating myotonic discharge with the voltage clamp protocol of a 50 Hz train pulse, the increment of chloride conductance was impaired in both wild-type/mutant heterodimers and mutant homodimers, clearly indicating a dominant-negative effect. Our data showed that slow activation gating of P480T ClC-1 impaired the increment of chloride conductance during repetitive depolarization, thereby accentuating the chloride conductance reduction caused by a slight depolarizing shift in the voltage-dependence of the channel gating. This pathophysiology may explain the clinical features of myotonia congenita.
Nature Medicine, 2011
The development of technologies for the in vitro amplification of the abnormal conformers of prio... more The development of technologies for the in vitro amplification of the abnormal conformers of prion protein (PrP Sc) has generated the potential for a novel diagnostic assay for prion disease. Previously, we developed a new PrP Sc amplification assay designated quaking-induced conversion (QUIC), which involves intermittent, automated shaking of the substrate, soluble recombinant PrP. We further improved the rapidity and practicality of this method by combining it with thioflavin T fluorescence to monitor the amyloid fibril formation. This assay, termed "real-time QUIC (RT-QUIC)", allows within 48 h, the detection of ≥1 fg of PrP Sc in diluted Creutzfeldt-Jakob disease (CJD) brain homogenate. Moreover, we assessed the technique first in a series of Japanese subjects, and then in a blind study of 30 cerebrospinal fluid specimens from Australia, which achieved greater than 80% sensitivity and 100% specificity. These findings indicate the promising enhanced diagnostic capacity of RT-QUIC in the ante-mortem evaluation of suspected CJD.
Laboratory Investigation, 2010
Periodic sharp wave complexes observed on an electroencephalographic recording and the presence o... more Periodic sharp wave complexes observed on an electroencephalographic recording and the presence of a 14-3-3 protein in the cerebrospinal fluid (CSF) are both included in the diagnostic criteria for the Creutzfeldt-Jakob disease (CJD) supplied by the World Health Organization; however, the presence or absence of the 14-3-3 protein in the CSF is sometimes difficult to discern on a western blot because of equivocal bands. The goal of this study was to establish a standard 14-3-3 protein assay and to determine the threshold level of a 14-3-3 protein that can be assayed by western blot. We searched for the most suitable isoform of the 14-3-3 protein to test for in protein assays, and the most sensitive antibody among four antibodies with an affinity for 14-3-3. We measured the levels of all 14-3-3 isoforms in 112 patients with CJD and in 100 patients with other diseases. We compared the performances of four different antibodies. We carried out a semi-quantitative analysis of g-isoform levels using the LAS 3000 system, which was capable of producing a digital image from the luminescence on a western blot. We determined that the most suitable isoform of the 14-3-3 protein for conducting a standardized assay was the g-isoform. Among the four commercially available antibodies for this protein, the most sensitive and specific was 18647 (IBL, Japan). We report the high repeatability of the detection of the 14-3-3 protein by this antibody to the g-isoform, showing that western blot can be used for semi-quantitative analysis.
Journal of the Neurological Sciences, 1987
The motor end-plate fine structure was studied in 3 patients with type A botulism and compared wi... more The motor end-plate fine structure was studied in 3 patients with type A botulism and compared with that in 4 patients with Lambert-Eaton myasthenic syndrome (LES). In the botulism cases a biopsy of the biceps brachii muscle was performed at the chronic stage. The skeletal muscle showed a neurogenic change. The nerve terminal area had decreased and the postsynaptic regions had been denuded of their nerve terminals in 16% of the regions (9.8% in control). No highly simplified postsynaptic regions were observed. The findings are consistent with those observed at the motor end-plates in motoneuron diseases. By contrast, in LES no changes were observed in the presynaptic region. In the postsynaptic region, the postsynaptic membrane length and membrane density decreased and hypertrophy of the junctional folds was not observed.
Journal of the Neurological Sciences, 2002
We previously reported elevated levels of serum interleukin-12 (IL-12) in association with increa... more We previously reported elevated levels of serum interleukin-12 (IL-12) in association with increased interferon-g (IFN-g) levels in patients with human T-lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The interaction between IL-12 and IL-12 receptor (IL-12R) plays an important role in differentiation of the T helper type 1 (Th1) phenotype. In this study, we further examined the IL-12/IL-12R axis by investigating the expression of IL-12R and CD40 ligand (CD40L) in peripheral blood mononuclear cells (PBMC) of 18 HAM/TSP patients, and comparing the levels with those in 25 patients with other neurological disorders, including 4 anti-HTLV-I-seropositive carriers as controls. Two-color analysis by flow cytometry revealed a significantly high percentage of IL-12R h1 + cells in CD4 + T lymphocytes in HAM/TSP patients compared to the control. Furthermore, IL-12R h2 mRNA expression in PBMC was detected by reverse-transcriptase polymerase chain reaction in 6 of 18 HAM/TSP patients, but not in any control patients. In contrast, there was no significant difference between the percentage of CD40L + cells in CD4 + T lymphocytes in HAM/TSP and control patients. Our results suggest Th1 immune activation in patients with HAM/TSP, which leads to chronic inflammation in the spinal cord, mediated by dysregulation of the IL-12/IL-12R axis rather than of the CD40/CD40L interaction.
Journal of the Neurological Sciences, 1998
We report a 73-year-old man with human T-lymphotropic virus type I (HTLV-I)-associated myelopathy... more We report a 73-year-old man with human T-lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM) complicated witḧ multi-organ inflammatory disease, including Sjogren's syndrome, interstitial cystitis, and uveitis. The presence of HTLV-I proviral DNA in peripheral blood mononuclear cells (PBMC), cerebrospinal fluid, salivary gland, mucosa of urinary bladder, and aqueous humor was confirmed by polymerase chain reaction using HTLV-I pX region primer. Western blot analysis revealed the presence of anti-HTLV-I antibodies in serum, CSF, saliva, and urine, suggesting replication of HTLV-I in each tissue. A high load of HTLV-I proviral DNA (20 copies out of 100 PBMC) was present, associated with increased spontaneous proliferation of peripheral blood lymphocytes (24 747 cpm). Our results suggest that the high load of HTLV-I in patients with HAM may potentially induce systemic inflammation in several organs.
Journal of the Neurological Sciences, 1998
We compared soluble E-selectin (sE-selectin) and L-selectin (sL-selectin) levels in sera and cere... more We compared soluble E-selectin (sE-selectin) and L-selectin (sL-selectin) levels in sera and cerebrospinal fluid (CSF) of 30 patients with human T-lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM), with those of 10 patients with the relapsing-remitting form of multiple sclerosis (MS), and 16 patients with other neurological diseases (OND). Serum levels of both sE-selectin and sL-selectin, as measured by enzyme-linked immunosorbent assay, were significantly elevated in patients with HAM, compared to patients with OND. In addition, serum levels of sL-selectin were significantly elevated in HAM patients compared to MS patients. No significant difference was found in CSF levels of sL-selectin between HAM patients and controls. However, HAM patients who had received blood transfusions had significantly higher CSF levels of sL-selectin than HAM patients without a past history of transfusions, suggesting that HAM patients with past history of transfusion have a more active immunological state in the central nervous system. sE-selectin was not detected in CSF of HAM patients and controls. This finding might be based on exaggerated inflammatory conditions following increased attachment of lymphocytes to activated endothelial cells in HAM patients.
Journal of Neuroimmunology, 1998
Using a 51Cr release assay, we investigated Fas-mediated cytotoxicity of peripheral blood CD4+ T ... more Using a 51Cr release assay, we investigated Fas-mediated cytotoxicity of peripheral blood CD4+ T cells of patients with human T-lymphotropic virus type-I (HTLV-I)-associated myelopathy (HAM) against T98G, a glioblastoma cell line which expresses Fas. Cytotoxic activity of CD4+ T cells against T98G was significantly higher in HAM patients than in controls. Moreover, when CD4+ T cells of HAM patients were preincubated with a monoclonal antibody to human Fas ligand (FasL), cytotoxic activity against T98G was significantly suppressed. These results suggest that damage to nervous tissues by the Fas/FasL system is involved in the pathogenesis of HAM.