Biomedical subjects

S Sakoda

Publications and source records attributed to S Sakoda.

At least 55 records · Page 3Linked to original sources

PubMed1999

Calcium increase in mouse skeletal muscles by triparanol: a drug to induce myotonic dystrophy-like clinical manifestations.

Triparanol (Trp) is known to cause clinical features similar to those seen in myotonic dystrophy, including myotonia, cataract and baldness. To explore the pathophysiological mechanism of myotonic dystrophy, we examined the effect of Trp on intracellular calcium in cultured skeletal myoblasts and myotubes as well as cardiac myocytes by using a fluorescent indicator. Trp preferentially induced increase of intracellular calcium in myotubes of skeletal muscles. Since the increase of calcium was inhibited by thapsigargin pretreatment but not by extracellular calcium elimination, it appears that triparanol might act mostly on intracellular calcium stores. Trp also inhibited the increase of calcium in myotubes induced by acetylcholine. Trp might cause myotonia possibly through the increase of intracellular calcium from intracellular stores.

Acetylcholine↗

PubMed1999

Casein kinase II is responsible for phosphorylation of NF-L at Ser-473.

Ser-473 is solely phosphorylated in vivo in the tail region of neurofilament L (NF-L). With peptides including the native phosphorylation site, it was not possible to locate responsible kinases. We therefore adopted full-length dephosphorylated NF-L as the substrate, and employed MALDI/TOF (matrix-assisted laser desorption and ionization/time of flight) mass spectrometry and a site-specific phosphorylation-dependent antibody recognizing Ser-473 phosphorylation. The antibody showed that casein kinase I (CK I) as well as casein kinase II (CK II) phosphorylated Ser-473 in vitro, while neither GSK-3beta nor calcium/calmodulin-dependent protein kinase II did so. However, the mass spectra of the tail fragments of the phosphorylated NF-L indicated that CK II was the kinase mediating Ser-473 phosphorylation in vitro as opposed to CK I, because CK I phosphorylated another site as well as Ser-473 in vitro. The antibody also demonstrated that NF-L phosphorylated at Ser-473 was abundant in the neuronal perikarya of the rat cortex, indicating that phosphorylation of Ser-473 may take place there. This result may support the suggestion that CK II is the kinase responsible for Ser-473 phosphorylation. Despite many reports showing that CK I mediates phosphorylation of neurofilaments, CK II may phosphorylate NF-L in vivo.

Amino Acid Sequence↗

PubMed1999

Benefit of a combined treatment with trientine and ascorbate in familial amyotrophic lateral sclerosis model mice.

We previously reported that the common toxic gain-of-function in various mutant copper-zinc superoxide dismutases (SOD1) seen in patients with familial amyotrophic lateral sclerosis (ALS) was an abnormal copper release from the enzyme protein. In this study, trientine and ascorbate, known to have a beneficial effect in an animal model of Wilson disease, were administered to transgenic mice overexpressing a mutated human SOD1 (G93A). The onset of neurological signs in the treated group was significantly delayed compared with that in the control group, and the time to reach total paralysis in the treated group was delayed as well. Since the agents used in this study cause low toxicity in animals and humans, this treatment may be a good candidate for clinical application.

Amyotrophic Lateral Sclerosis↗

PubMed1999

A novel MPZ gene mutation in dominantly inherited neuropathy with focally folded myelin sheaths.

We found the association of a heterozygous novel MPZ gene point mutation, Ile62Phe in exon 2, with autosomal dominant motor and sensory neuropathy with focally folded myelin sheaths. Family study revealed that de novo Ile62Phe mutation on the MPZ gene occurred in the proband and was inherited by her children with early onset slowly progressive neuropathy. Our study suggests that the characteristic pathologic findings of the sural nerve in these patients are closely related to the site and nature of amino acid substitutions of the MPZ gene.

Child↗

PubMed1999

Ibudilast, a phosphodiesterase inhibitor, ameliorates experimental autoimmune encephalomyelitis in Dark August rats.

A phosphodiesterase inhibitor (PDEI), Ibudilast, which has been in wide use for the management of bronchial asthma and cerebrovascular disease in Japan, was tested for its clinical efficacy on experimental autoimmune encephalomyelitis (EAE) in Dark August rats. The severity of acute EAE was significantly ameliorated by prophylactic oral treatment with Ibudilast (10 mg/kg per day) starting on the day of immunization, although it did not modify the course of the disease when it was given after the onset of the first clinical sign of EAE. Histologically, inflammatory cell infiltration in the lumbar spinal cord was significantly reduced in Ibudilast-treated animals as compared to control animals. Ibudilast mildly suppressed MBP-induced proliferation of T cells in regional lymph nodes, the secretion of interferon-gamma from T cells activated by MBP in CFA, and the secretion of tumor necrosis factor-alpha from macrophages. While the in vitro studies did not suggest difference between Ibudilast and other PDEIs such as rolipram, the clinical dose of Ibudilast is approximately 200-fold higher than that of rolipram and the effective dose of Ibudilast was relatively close to what has been therapeutically used in patients. Thus, Ibudilast may be a candidate for clinical use for patients with multiple sclerosis. 1999 Elsevier Science B.V. All rights reserved.

Administration, Oral↗

PubMed1999

The effect of dehydroepiandrosterone sulfate administration to patients with multi-infarct dementia.

We measured cerebrospinal fluid (CSF) levels of dehydroepiandrosterone sulfate (DHEAS) by radioimmunoassay in seven patients with multi-infarct dementia (MID), fourteen age- and gender-matched non-demented patients with a history of cerebral infarction and fifteen age- and gender-matched patients without neurological disorders. The levels of DHEAS in CSF of patients with MID were significantly lower than those in non-demented patients with a history of cerebral infarction or those in patients without neurological disorders. Daily intravenous administration of 200 mg DHEAS for 4 weeks markedly increased serum and CSF levels of DHEAS in seven MID patients, improved decrease of daily activities and emotional disturbances in three patients and EEG abnormalities in two patients. The DHEAS therapy may provide a beneficial effect on MID patients.

Activities of Daily Living↗

PubMed1999

Adult onset limb-girdle type mitochondrial myopathy with a mitochondrial DNA np8291 A-to-G substitution.

We analyzed mitochondrial DNA (mtDNA) from 7 patients in four families with adult onset limb-girdle type mitochondrial myopathy to clarify their genetic background. The patients, 2 men and 5 women, showed common clinical features, characterized by isolated skeletal myopathy, high serum creatine kinase level, ragged-red fibers and cytochrome c oxidase-defective fibers. Analysis of muscle biopsy specimens indicated that cytochrome c oxidase activity was decreased relative to that of citrate synthase in 5 of the 7 patients. Southern blotting and direct sequence analyses showed an A-to-G homoplasmic transition at np8291 and intergenic COII/tRNA (Lys) 9bp deletion in all patients. This substitution was detected in only 2 of 600 control individuals including healthy subjects and patients with other neuromuscular disorders; these 2 individuals had diabetes mellitus and myotonic dystrophy, respectively. Consequently, the mtDNA transition at np8291 was a rare polymorphism. However, the 7 patients we studied had identical clinical, pathological, biochemical, and genetic features. Therefore, limb-girdle type mitochondrial myopathy with this rare polymorphism may form a subgroup of adult onset mitochondrial myopathy.

Adult↗

PubMed1999

Myelin-associated oligodendrocytic basic protein is essential for normal arrangement of the radial component in central nervous system myelin.

We previously reported that myelin-associated oligodendrocytic basic protein (MOBP) was abundantly expressed in the central nervous system (CNS) myelin, and shared several characteristics with myelin basic protein (MBP). In particular, a cluster of positively charged amino acids was considered to facilitate compaction of the cytoplasmic face of the myelin sheath, as in the case of MBP. However, the contribution of MOBP in forming and maintaining the myelin sheath still remains unclear. Recent investigations showed that one isoform of MOBP was expressed in the embryo prior to myelination, and MOBP isoforms were colocalized with the microtubular network and nucleus in vitro. To explore the role of MOBP in vivo, we generated MOBP-deficient mice and analysed the CNS myelin. Surprisingly, the compact myelin was formed, however, the myelin from MOBP-deficient mice exposed to hexachlorophene, a known dysmyelinating agent, showed widening of the major dense lines. These results suggest that MOBP is not essential for myelin formation, but reinforces the apposition of the cytoplasmic faces of the myelin sheath. A striking phenotype of MOBP-deficient mice was the presence of the straight 'condensed' radial component. This component has been described as a tight junction-like complex running radially and zig-zag through the CNS myelin sheath between inner and outer mesaxons. These results suggest that MOBP is essential for normal arrangement of the radial component.

Animals↗

PubMed1999

A cephalometric study of the relationship between the level of velopharyngeal closure and the palatal plane in patients with repaired cleft palate and controls without clefts.

To find out whether the palatal plane is a useful indicator for evaluating the level of velopharyngeal closure, we did a cross-sectional study from early childhood to puberty of the vertical relationship between the palatal plane and the level of velarpharyngeal contact during velopharyngeal functioning in 61 patients with repaired cleft palate (unilateral cleft lip and palate = cleft group) and 82 controls without clefts (control group). Measurements on the vertical dimension were derived from a coordinate system and landmarks on lateral cephalograms, and the significance of differences in measurements was analysed using Student's t-test. Changes in the points of velarpharyngeal contact in relation to the palatal plane with growth showed a consistent tendency though differed between the two groups. In the control group, the PPW (point where palatal plane extension intersects the posterior pharyngeal wall) was maintained at a level that did not differ significantly from the level of midpoint of velarpharyngeal contact during phonation of /a/, and was maintained at a level that did not differ significantly from the level of the inferior point of velarpharyngeal contact. In the cleft group, however, it was maintained at a level that was slightly higher than the superior point of velarpharyngeal contact both during phonation of /a/ and during blowing. These results suggest that the palatal plane is useful as an indicator for evaluating the level of velopharyngeal closure.

Adolescent↗

PubMed1999

A cephalometric study of the stability of the base of the pharyngeal flap following a modified 'unified velopharyngoplasty procedure'.

A cephalometric study was conducted on 12 patients with repaired cleft palate to evaluate the stability in level and length of the base attachment of the velopharyngeal complex following pharyngeal flap surgery by a modified velopharyngoplasty. Complete velopharyngeal closure and normal articulation with a speech appliance were confirmed in all patients prior to pharyngeal flap surgery, which was performed on patients 10 years of age and above. Cephalometric radiographs were taken immediately, 1 year, 2 years and 3 years postoperatively. Cephalometric analysis revealed that although the level and length of the base of the velopharyngeal complex showed changes during the first postoperative year, they remained stable when compared with the palatal plane during the last two years. This indicated therefore that the base of a velopharyngoplasty should be attached at the same level of the palatal plane, namely the level of velopharyngeal closure, and that the procedure appeared useful in producing a stable velopharyngeal complex.

Adolescent↗

PubMed1999

Increased pain sensitivity of the upper extremities of TMD patients with myalgia to experimentally-evoked noxious stimulation: possibility of worsened endogenous opioid systems.

The purpose of this study was to examine whether or not temporomandibular disorder (TMD) patients with chronic masticatory myalgia have increased pain sensitivity at remote sites outside of the head and neck region, and to evaluate whether the endogenous pain inhibitory systems triggered ischemic pain functions favorably in those patients. Twenty female TMD patients with chronic myalgia and 20 controls participated in this study. Ischemic pain was produced to activate endogenous opioids. The pain threshold time, pain tolerance time, pain intensity and pain unpleasantness were compared between the TMD patients and controls. The pressure pain thresholds in the hand were also compared before, between, and immediately after the ischemic pain. The TMD patients showed higher severe pain intensity and unpleasantness values and had lower pressure pain thresholds in the hand. Although both groups showed an increase in the pressure pain threshold, there was less of an increase in the pressure pain threshold in the TMD patients than in the controls. These findings indicate that TMD patients have increased pain sensitivity at remote sites, and also indicate additional evidence that the endogenous opioid systems may become impaired in TMD patients with chronic masticatory myalgia.

Adult↗

PubMed1998

The pattern of cytokine gene expression in lymphoid organs and peripheral blood mononuclear cells of mice with experimental allergic encephalomyelitis.

We previously observed Th1-dominated response in the central nervous system (CNS) of mice during the course of experimental allergic encephalomyelitis (EAE) with a semiquantitative reverse transcriptase-polymerase chain reaction (RT/PCR) analysis. We report here that mRNA levels for both inflammatory cytokines including interleukin (IL)-1beta, IL-2, IL-6, interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha and TNF-beta and immunoregulatory cytokines including IL-4, IL-10 and transforming growth factor (TGF)-beta were up-regulated in the preclinical and/or acute phase but down-regulated in the recovery phase of EAE in lymph node (LN) of mice. Similar profiles for cytokine mRNA levels were also observed in spleen and peripheral blood mononuclear cells (PBMC). The present study also showed that a significant down-regulation of the mRNA level for IL-6 in the acute phase as compared with the preclinical phase, and a significant reduction of the mRNA level for TGF-beta in the preclinical and acute phase as compared with the corresponding mRNA levels in the control mice treated with complete Freund's adjuvant alone were characteristic in peripheral immune organs of mice with EAE. These results indicate that no particular bias in cytokine production occurred in peripheral immune organs of mice with actively induced relapsing EAE, and that the relative reduction in production of TGF-beta or IL-6 in peripheral circulation might participate in the induction or remission of EAE, respectively. Our results using the animal model of multiple sclerosis (MS) suggested that the mRNA levels for IL-6 and TGF-beta in PBMC from patients with MS may be a good indicator to assess the disease activity or to predict relapse.

Animals↗

PubMed1998

Simple and defined method to detect the SOD-1 mutants from patients with familial amyotrophic lateral sclerosis by mass spectrometry.

Mutations in Cu/Zn superoxide dismutase (SOD1) cause a subset of cases of familial amyotrophic lateral sclerosis (FALS). We established a simple and defined method to detect the mutant SODI in erythrocytes by electrospray ionization mass spectrometry (ESIMS) using materials precipitated with specific antiserum. Hemolysate was mixed with anti-SOD1 antiserum and the generated precipitate, which was soluble in the solvent for MS analysis, was injected on to an LC column connected to an ESI-mass spectrometer. MS spectra of the reduced SOD1 prepared from normal individuals showed ion peaks corresponding to free monomer SOD1. The spectra from FALS patients revealed doublet ion peaks corresponding to normal and mutant components. The ratios of mutant to normal SOD1 were about 1/2 in cases of (G37R) and (A4S), and about 0.15 in a case of (H46R). This method provides for the rapid diagnosis using small amount of specimens, and will contribute to elucidate the pathomechanism of FALS through the quantification of SOD1 mutants in erythrocytes and in tissues of nervous systems.

Amino Acid Substitution↗

PubMed1998

Domain- and site-specific phosphorylation of bovine NF-L by Rho-associated kinase.

Rho-associated kinase (Rho-kinase), the putative target of the small GTP-binding protein Rho, phosphorylated neurofilament protein (NF-L) in vitro with approximately 1 mole phosphate per mole NF-L. Phosphorylated NF-L no longer formed the 10 nm filaments, and NF-L filaments were phosphorylated with a result of nearly complete disassembly. NF-L phosphorylated by Rho-kinase was digested with trypsin, and digested fragments were assigned by MALDI/TOF. Unique phosphorylation sites were found at Ser-26 and Ser-57 in the head domain of NF-L. These results indicate that domain- and site-specific phosphorylation by Rho-kinase may regulate the assembly-disassembly of NF-L filaments.

Amino Acid Sequence↗

PubMed1998

Fas has a crucial role in the progression of experimental autoimmune encephalomyelitis.

To investigate the role of Fas in experimental autoimmune encephalomyelitis (EAE) in mice, we examined the susceptibility of EAE in C57BL/6 (B6).lpr mice lacking Fas. The frequency of myelin oligodendrocyte glycoprotein (MOG)-induced EAE in B6.lpr mice was significantly lower than that in B6 mice (19% vs 94%). However, no significant difference was observed between them in either the lymphocyte proliferation response or antibody reactivity to MOG. In addition, the histological examination and semiquantitative reverse transcriptase polymerase chain reaction analysis revealed that the infiltration of inflammatory cells and the up-regulation of gene expression for inflammatory cytokines occurred in the central nervous system (CNS) of B6.lpr mice immunized with MOG, even if they showed no clinical sign. These results indicate that Fas may contribute to the pathogenesis of EAE and may play a crucial role in the expansion of inflammation and/or myelin destruction in the CNS rather than in the activation of encephalitogenic T cells in the periphery and/or the breakdown of blood brain barrier.

Animals↗

PubMed1998

Aminoguanidine, a selective inhibitor of the inducible nitric oxide synthase, has different effects on experimental allergic encephalomyelitis in the induction and progression phase.

To elucidate the role of excessive nitric oxide (NO) via the inducible nitric oxide synthase (iNOS) in experimental allergic encephalomyelitis (EAE), the effect of a selective iNOS inhibitor, aminoguanidine, was investigated using mice with actively induced EAE. Administration of aminoguanidine by intraperitoneal or intracisternal injection from day 2 to day 12 after immunization produced a significant delay in the onset of EAE. On the other hand, administration of aminoguanidine by intraperitoneal or intracisternal injection for 10 days after the onset of EAE enhanced the clinical severity and mortality rate and hastened the onset of relapse significantly. The histological study at day 11 after the onset revealed that more inflammatory cells were present in the central nervous system of mice treated with aminoguanidine as compared with mice without aminoguanidine treatment. These results suggested that NO via iNOS was a pathogenetic factor in the induction phase of EAE, but had an inhibitory role in the progression phase of EAE. Although the effect of NO synthase inhibitors on EAE has been controversial, the present study suggested that the timing of administration might be an important consideration and might explain the previous contradictory reports.

Acute Disease↗

PubMed1998

A cephalometric study by multivariate analysis of growth of the bony nasopharynx in patients with clefts and non-cleft controls.

To clarify the characteristics of growth of the nasopharynx, comparison of the cephalometric growth of bones surrounding nasopharynx between 61 patients with complete unilateral cleft lip and palate (UCLP group) and 82 non-cleft controls (NCC group) was carried out. All of the subjects were divided into four developmental stages (i.e. stage 1 at 4 years of age, stage 2 at 8 years of age, stage 3 at 12 years of age and stage 4 at 17 years of age). Measurements on the antero-posterior and the vertical dimensions were derived from a coordinate system and points on bones surrounding the nasopharynx on lateral X-ray cephalograms, and results were analyzed by multivariate analysis and t-test. The results showed that (a) the posterior maxillary point (PMP) in the UCLP group was located more postero-superiorly than that in the NCC group, and this was the main factor that allows discrimination between the two groups and (b) the cranial base, posterior maxilla and the cervical vertebrae were found to be in independent in growth, however, the nasopharyngeal triangle connecting three points on these three bones (Ho: cranial base; PMP: posterior maxillary point; At: atlas) showed harmonious growth in both the UCLP and NCC groups.

Adolescent↗

PubMed1998

Encephalitogenicity of myelin-associated oligodendrocytic basic protein and 2',3'-cyclic nucleotide 3'-phosphodiesterase for BALB/c and SJL mice.

In search of new encephalitogenic myelin antigens, the 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP) and 19 000 MW isoform of myelin-associated oligodendrocytic basic protein (MOBP) were obtained as recombinant proteins by the baculovirus expression system in Spodoptera frugiperda cells and purified to homogeneity by immobilized metal chelate affinity chromatography (IMAC). The purified MOBP was soluble in water and showed retarded migration on sodium dodecyl sulphate-polyacrylamide gel electrophoresis similar to myelin basic protein (MBP). MOBP induced experimental autoimmune encephalomyelitis (EAE) in nine of 15 susceptible SJL OlaHsd mice, causing death in two animals, whereas three of 14 BALB/c mice showed mild symptoms of EAE, manifested as transient weakness of hind limbs. In both mouse strains, periventricular infiltrates of mononuclear cells were observed. In addition, both 46 000 MW and 48 000 MW CNP isoforms were shown to be non-encephalitogenic for both mouse strains.

2',3'-Cyclic Nucleotide 3'-Phosphodiesterase↗