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Biomedical subjects

Norio Ohkoshi

Publications and source records attributed to Norio Ohkoshi.

18 recordsLinked to original sources
PubMed2005

ANCA-associated vasculitis (AAV) causing bilateral cerebral infarction and subsequent intracerebral hemorrhage without renal and respiratory dysfunction.

A 56-year-old man complained of headache and the analgesia of the four extremities. Laboratory data presented signs of inflammation, but no other abnormality such as renal or respiratory dysfunction. Two months after the appearance of the primary symptoms, he developed cerebral infarction of the bilateral corona radiata. The patient did not have any of the risk factors for cerebrovascular disease. He was diagnosed with anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) because the systemic examinations revealed only that he tested positive for anti-neutrophil cytoplasmic autoantibody (ANCA). Moreover, the biopsy of the sural nerve displayed microscopic polyangitis (MPA). Despite undergoing steroid pulse therapy, the patient died from the fatal cerebral hemorrhage. The clinical course of AAV is rapid progressive. In cases of atypical cerebrovascular disease, the possibility of ANCA should be investigated.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed2005

An autosomal dominant cerebellar ataxia linked to chromosome 16q22.1 is associated with a single-nucleotide substitution in the 5' untranslated region of the gene encoding a protein with spectrin repeat and Rho guanine-nucleotide exchange-factor domains.

Autosomal dominant cerebellar ataxia (ADCA) is a group of heterogeneous neurodegenerative disorders. By positional cloning, we have identified the gene strongly associated with a form of degenerative ataxia (chromosome 16q22.1-linked ADCA) that clinically shows progressive pure cerebellar ataxia. Detailed examination by use of audiogram suggested that sensorineural hearing impairment may be associated with ataxia in our families. After restricting the candidate region in chromosome 16q22.1 by haplotype analysis, we found that all patients from 52 unrelated Japanese families harbor a heterozygous C-->T single-nucleotide substitution, 16 nt upstream of the putative translation initiation site of the gene for a hypothetical protein DKFZP434I216, which we have called "puratrophin-1" (Purkinje cell atrophy associated protein-1). The full-length puratrophin-1 mRNA had an open reading frame of 3,576 nt, predicted to contain important domains, including the spectrin repeat and the guanine-nucleotide exchange factor (GEF) for Rho GTPases, followed by the Dbl-homologous domain, which indicates the role of puratrophin-1 in intracellular signaling and actin dynamics at the Golgi apparatus. Puratrophin-1--normally expressed in a wide range of cells, including epithelial hair cells in the cochlea--was aggregated in Purkinje cells of the chromosome 16q22.1-linked ADCA brains. Consistent with the protein prediction data of puratrophin-1, the Golgi-apparatus membrane protein and spectrin also formed aggregates in Purkinje cells. The present study highlights the importance of the 5' untranslated region (UTR) in identification of genes of human disease, suggests that a single-nucleotide substitution in the 5' UTR could be associated with protein aggregation, and indicates that the GEF protein is associated with cerebellar degeneration in humans.

5' Untranslated Regions↗
PubMed2005

A pediatric case of critical illness polyneuropathy: clinical and pathological findings.

Critical illness polyneuropathy (CIP) is a sensorimotor polyneuropathy recognized in adult intensive care patients with sepsis and multiple organ dysfunction and only a few cases have been reported in children. Here we report a 13-year-old Japanese boy with CIP that developed during the course of encephalopathy. Two months after the onset of encephalopathy, he developed tetraplegia although consciousness had already recovered. Deep tendon reflex was absent. MRI of the brain and spinal cord was normal and no abnormality in the cerebrospinal fluid was detected. Motor and sensory nerve conduction velocities of the lower limbs and somatosensory evoked potential could not be detected. The motor activity subsequently showed gradual recovery, although standing and walking could not be achieved. Sural nerve biopsy performed 3 years after the onset showed severe reduction of the number of myelinated large-diameter fibers, thin myelin in almost all fibers and cluster formation of myelinated small-diameter fibers, indicating primary axonal degeneration with regeneration. We report here for the first time the neuropathological changes in peripheral nerves during the chronic stage of CIP in children.

Adolescent↗
PubMed2004

Clathrin isoform CHC22, a component of neuromuscular and myotendinous junctions, binds sorting nexin 5 and has increased expression during myogenesis and muscle regeneration.

The muscle isoform of clathrin heavy chain, CHC22, has 85% sequence identity to the ubiquitously expressed CHC17, yet its expression pattern and function appear to be distinct from those of well-characterized clathrin-coated vesicles. In mature muscle CHC22 is preferentially concentrated at neuromuscular and myotendinous junctions, suggesting a role at sarcolemmal contacts with extracellular matrix. During myoblast differentiation, CHC22 expression is increased, initially localized with desmin and nestin and then preferentially segregated to the poles of fused myoblasts. CHC22 expression is also increased in regenerating muscle fibers with the same time course as embryonic myosin, indicating a role in muscle repair. CHC22 binds to sorting nexin 5 through a coiled-coil domain present in both partners, which is absent in CHC17 and coincides with the region on CHC17 that binds the regulatory light-chain subunit. These differential binding data suggest a mechanism for the distinct functions of CHC22 relative to CHC17 in membrane traffic during muscle development, repair, and at neuromuscular and myotendinous junctions.

Animals↗
PubMed2004

[Regional anesthesia for a patient with stiff-person syndrome].

We report a case of stiff-person syndrome (SPS). A 65-year-old male underwent an emergency pacemaker implantation for syncope. With lidocaine infiltration under fentanyl and propofol sedation, the operation was completed without complications. Muscle rigidity and spasms are exacerbated by sensory and emotional stimuli in SPS. However, the present case suggests that regional anesthesia is also acceptable under adequate sedation.

Aged↗
PubMed2003

Eicosapentaenoic acid suppresses basal and insulin-stimulated endothelin-1 production in human endothelial cells.

cis-Polyunsaturated fatty acids such as eicosapentaenoic acid (EPA) are the major fatty acids contained in fish oil, and are known to affect the various physiological properties of cell membranes in humans. The present study investigated the effects of polyunsaturated fatty acids on endothelin-1 (ET-1) production in human umbilical vein endothelial cells (HUVECs) and on insulin activity. After addition of various concentrations of EPA, docosahexaenoic acid, arachidonic acid, or linoleic acid to a culture medium, the concentration of ET-1 was measured using ELISA, and that of ET-1 mRNA was determined by RT-PCR. The results showed that EPA had the strongest inhibitory effect (p<0.05) on both basal ET-1 production and ET-1 mRNA levels. In addition, insulin (1 micromol/l) markedly increased ET-1 production, and EPA also significantly decreased the effect induced by insulin. Pretreatment with Ca2+ chelator EGTA (1 mmol/l), NOS inhibitor L-NAME (300 micromol/l), or calmodulin antagonist W-7 (300 micromol/l) inhibited NO production by EPA (100 micromol/l), but these pretreatments had no effect on ET-1 production by EPA. These findings suggest that EPA reduces basal and insulin-enhanced ET-1 production by inhibiting ET-1 mRNA production. These effects of EPA may contribute to its vasorelaxant and anti-atherosclerotic effects.

Cells, Cultured↗
PubMed2002

Degeneration of skeletal muscle fibers in the rat administrated carbon tetrachloride: similar histological findings of the muscle in a 64-year-old patient of LC with muscle cramp.

It is well known that painful muscle cramps occur frequently in patients with advanced liver cirrhosis (LC). Although many studies discuss the pathophysiological causes of these muscle cramps in various conditions, the results are not clear as far as the cause associated to LC is concerned. In order to investigate the cause of muscle cramps in LC, we examined the histological findings of skeletal muscle fibers in LC rat model and in a patient with LC. LC (n=9) was induced in rats by chronic carbon tetrachloride administration. The histological findings of skeletal muscle tissues from the lower leg in LC rats and those of the upper arm in a patient with LC were compared. The degenerated muscle fibers and centronucleus in LC rats were similar to the opaque fibers frequently observed in myotonic dystrophy with severe muscle rigidity in patients with LC. In conclusion, results of this study suggest that one of the causes for muscle cramps in patients with LC is due to skeletal muscle fiber degeneration. Therefore, histological observation of skeletal muscle fibers should be considered in the treatment of painful muscle cramps.

Journal Article↗
PubMed2002

The expression of alpha-dystrobrevin and dystrophin during skeletal muscle regeneration.

The expression of alpha-dystrobrevin and dystrophin in rat tibialis anterior muscles was chronologically evaluated during a cycle of regeneration after myonecrosis induced by the injection of cardiotoxin. In immunohistochemical studies, alpha-dystrobrevin and dystrophin were first stained weakly at the sarcolemma of some regenerating muscle fibers on day 5. On day 7, alpha-dystrobrevin was still stained weakly, whereas dystrophin was stained conspicuously. After day 10, alpha-dystrobrevin and dystrophin were both stained conspicuously on almost all regenerating muscle fibers. In the Western blot analysis, alpha-dystrobrevin and dystrophin were first detected as visible bands on days 5 and 7, respectively. The bands of alpha-dystrobrevin and dystrophin both darkened sequentially up to day 10. The protein levels based on the densitometrical analysis of the bands on each day were converted to the percentage of the protein level on day 28, which was taken as 100%. The sequential line based on these data showed that alpha-dystrobrevin and dystrophin reached 50% of the protein level on day 28 by 6.6 and 5.3 days, respectively. These data provide evidence that alpha-dystrobrevin regenerates more slowly than dystrophin in skeletal muscle.

Animals↗
PubMed2002

The expression of neuronal nitric oxide synthase and dystrophin in rat regenerating muscles.

We investigated the expression of neuronal nitric oxide synthase (nNOS) and dystrophin in the regenerating skeletal muscles of rats after cardiotoxin-induced myonecrosis by immunohistochemical studies and western blot analysis. In normal muscles, nNOS was moderately immunostained on type 2B fibers, but was faintly immunostained on type 2A or type 1 fibers. In immunohistochemical studies of regenerating muscles, nNOS was first observed at the sarcolemma of type 2B fibers on day 10, when the type discrimination between types 2A and 2B was first detected by ATP reactions. Subsequently, the immunostaining of nNOS grew progressively stronger in type 2B fibers, with faint staining in type 2A and type I fibers until day 28. Meanwhile, the immunostaining of dystrophin grew stronger equally in all three fibers until day 21. In western blot analysis of regenerating muscles, nNOS regenerated more slowly than dystrophin. The present data suggest that the expression of nNOS is related to the muscle fiber type differentiation, and that the role of nNOS is related to the function of the type 2B fibers of the muscle.

Animals↗
PubMed2002

The expression of dystrophin, alpha-sarcoglycan, and beta-dystroglycan during skeletal muscle regeneration: immunohistochemical and western blot studies.

We evaluated re-expression of dystrophin, alpha-sarcoglycan and beta-dystroglycan in regenerating skeletal muscles of rats after cardiotoxin-induced myonecrosis in order to understand the dynamic behaviour of these proteins during the regeneration process. Immunohistochemical staining of these proteins almost disappeared in the sarcolemma of necrotic fibers on the 1st day, and was obscured due to non-specific staining on the 3rd day. Dystrophin was labeled faintly at the sarcolemma of regenerating muscle fibers on the 5th day. From the 5th day to the 10th day, levels of immunostaining of dystrophin increased. After the 14th day, dystrophin was stained conspicuously. alpha-Sarcoglycan was labeled weakly at the sarcolemma of small regenerating muscle fibers on the 5th day and was labeled conspicuously after the 7th day. beta-Dystroglycan was labeled moderately at the sarcolemma of regenerating muscle fibers on the 5th day and was labeled conspicuously after the 7th day. In western blot analysis, beta-dystroglycan persisted throughout the entire cycle of myonecrosis and regeneration, and re-expression of alpha-sarcoglycan progressed faster than that of dystrophin. We speculate that regeneration advances from the basement membrane side to the subsarcolemmal side, and that proteins at the basement membrane side resist disruption and have a high capacity for regeneration.

Animals↗
PubMed2002

[A case of sensory perineuritis with Bowen disease].

A 60-year-old man was admitted because of subacutely progressive sensory disturbance characterized by fluctuating dysesthesia and light pain on the skin of his hands and feet. He exhibited mononeuritis multiplex, and a plaque with sloughing was observed on the left side of his back. Sural nerve biopsy revealed marked thickening of the perineurium with vascularization, and no necrotizing vasculitis. The pathological features of the nerve biopsy were compatible with sensory perineuritis. A biopsy from his skin lesion revealed Bowen's disease. There have been several reported cases of sensory perineuritis accompanied by malignant tumors. In these cases, immune dysfunctions were considered a common underlying cause in both diseases. This is the first reported case of sensory perineuritis associated with Bowen's disease.

Bowen's Disease↗