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Biomedical subjects

K Ikezoe

Publications and source records attributed to K Ikezoe.

12 recordsLinked to original sources

Expression of granulysin in polymyositis and inclusion-body myositis.

BACKGROUND: Granulysin, a recently defined cytolytic molecule, is expressed in cytotoxic T cells and natural killer cells in a similar way to perforin, which is reported to have a major role in the pathogenesis of polymyositis and inclusion-body myositis (IBM). OBJECTIVE: To clarify the role of granulysin in polymyositis and IBM. METHODS: The expression of granulysin and perforin was examined by double staining with CD8, CD4 and CD56 in endomysial infiltrating cells and autoinvasive cells in muscle biopsy specimens of 17 patients with polymyositis (6 steroid resistant and 11 steroid responsive) and of 7 patients with IBM. RESULTS: Similar to perforin, granulysin was expressed in CD8, CD4 or CD56 cells in patients with polymyositis and IBM. The ratio of cells double positive for granulysin and CD8 to all CD8 cells at endomysial sites was notably higher in steroid-resistant polymyositis than in steroid-responsive polymyositis and IBM. CONCLUSION: Granulysin expression in CD8 cells seems to be correlated with steroid resistance in polymyositis.

Antigens, Differentiation, T-Lymphocyte↗

Schwann cell myelination occurred without basal lamina formation in laminin alpha2 chain-null mutant (dy3K/dy3K) mice.

The laminin alpha2 chain is a major component of basal lamina in both skeletal muscle and the peripheral nervous system. Laminin alpha2 chain deficiency causes merosin-deficient congenital muscular dystrophy, which affects not only skeletal muscles, but also the peripheral and central nervous systems. It has been reported that the formation of basal lamina is required for myelination in the peripheral nervous system. In fact, the spinal root of dystrophic mice (dy/dy mice), whose laminin alpha2 chain expression is greatly reduced, shows lack of basal lamina and clusters of naked axons. To investigate the role of laminin alpha2 chain and basal lamina in vivo, we examined the peripheral nervous system of dy3K/dy3K mice, which are null mutants of laminin alpha2 chain. The results indicate the presence of myelination although Schwann cells lacked basal lamina in the spinal roots of dy3K/dy3K mice, suggesting that basal lamina is not an absolute requirement for myelination in vivo. Immunohistochemically, the expression of laminin alpha4 chain was increased and laminin alpha5 chain was preserved in the endoneurium of the spinal root. Laminin alpha4 and alpha5 chains may play the critical role in myelination instead of laminin alpha2 chain in dy3K/dy3K mice. In addition, the motor conduction velocity of the sciatic nerve was significantly reduced compared with that of wild-type littermate. This reduction in conduction velocity may be due to small axon diameter, thin myelin sheath and the patchy disruption of the basal lamina of the nodes of Ranvier in dy3K/dy3K mice.

Animals↗

Apoptotic muscle fiber degeneration in distal myopathy with rimmed vacuoles.

Rimmed vacuole formation, tubulofilamentous nuclear inclusions and muscle fiber atrophy are the characteristic pathological findings in distal myopathy with rimmed vacuoles (DMRV). Necrotic muscle fibers were few in number and did not appear to account for the muscle weakness, but the nuclear changes with myofibrillar degeneration followed by rimmed vacuole formation appeared to be the major reason for the muscle fiber atrophy in DMRV. To determine whether the nuclear change in DMRV was related to apoptosis, we examined 15 muscle biopsy specimens immunohistochemically, and 7 of them ultrastructurally. The characteristic tubulofilamentous nuclear inclusions were found in 4 and the typical fragmented apoptotic nuclei in 3 of the 7 muscle biopsy samples examined by electron microscopy. TUNEL-positive nuclei reflecting apoptotic DNA fragmentation were found in 13 of 15 biopsies ranging from a few to approximately 1.5% of myonuclei. Apoptosis-specific protein was expressed in the sarcoplasm of atrophic fibers in 13 biopsies both with or without rimmed vacuoles. These findings suggest that the apoptotic process plays a crucial role in myofibrillar degeneration followed by autophagocytosis, i.e., rimmed vacuole formation, in DMRV.

Adult↗

Oculopharyngodistal myopathy is genetically heterogeneous and most cases are distinct from oculopharyngeal muscular dystrophy.

The question whether oculopharyngodistal myopathy (MIM 164310) is a distinct disease entity or a variant of oculopharyngeal muscular dystrophy (MIM 164300) persists. To answer this question, we examined five patients with the clinical characteristics of oculopharyngodistal myopathy for GCG expansion in poly(A)-binding protein nuclear 1 gene (previously called poly(A)-binding protein 2), the causative gene defect for oculopharyngeal muscular dystrophy. Only one of our five patients had the significant GCG expansion. Thus, oculopharyngodistal myopathy is a genetically heterogeneous disorder, which includes patients with oculopharyngeal muscular dystrophy but, for the most part, is different genetically from oculopharyngeal muscular dystrophy.

Aged↗

[HIV myopathy].

Explore the source record for details and available documents.

Diagnosis, Differential↗

A novel congenital myopathy with apoptotic changes.

We report on a female child with congenital myopathy with delayed developmental milestones and mental retardation. The most striking pathological finding was the presence of many condensed to fragmented myonuclei. DNA fragmentation was confirmed by the TUNEL method and supported by the ultrastructural characteristics of apoptotic nuclear changes. We also demonstrated immunohistochemically the activation of caspase-3 and caspase-9. This appears to be the first reported case of congenital myopathy with apoptotic process.

Apoptosis↗

Autosomal dominant familial spinal and bulbar muscular atrophy with gynecomastia.

The proband, a 53-year-old man, developed progressive spinal and bulbar muscular atrophy and gynecomastia at the age of 50. His father had weakness of lower limbs, and his son had a nasal voice, ocular movement abnormalities, and gynecomastia, whereas two of the proband's brothers showed either gynecomastia or tongue fasciculations. None of the patients showed any expansion of CAG repeat in the androgen receptor gene or any hormonal abnormality. Thus, this family is affected by a form of autosomal dominant spinal and bulbar muscular atrophy with gynecomastia.

Chromosome Aberrations↗

Mutations of calpain 3 gene in patients with sporadic limb-girdle muscular dystrophy in Japan.

Mutations of the calpain 3 gene, an intracellular calcium-activated neutral protease, is one of the causes of limb-girdle muscular dystrophy (LGMD). We examined 14 Japanese patients with sporadic LGMD for calpain 3 mutations, and found four mutations in five patients. Three (R461C, D707G and R147P) were novel missense mutations, and one was a splice-site mutation (801+1g-->a) resulting in skipping of exons 4 and 5. Of the five patients, three patients with homozygous missense mutations showed later onset and slower progression than the other two patients with an exon skipping or mRNA loss of unknown cause. It would appear that the occurrence of calpain 3 gene mutations in sporadic LGMD in Japan may be quite high since all five patients with mutations in this gene were among the 14 patients without apparent family history, an incidence of 36%. These findings also suggest that calpain 3 deficiency occurs in both sporadic and familial LGMD and that direct analysis of the calpain 3 gene may be useful in the definitive diagnosis not only of the 15q-linked familial but also of sporadic cases of LGMD.

Adolescent↗

[Polymyositis and cutaneous vasculitis in a patient with myelodysplastic syndrome].

We report a 60-year-old man with myelodysplastic syndrome (MDS) who developed polymyositis and cutaneous vasculitis. He noticed difficulty in climbing up stairs 4 months before admission. On admission, he showed brownish skin pigmentation in the distal positions of the four extremities. Neurological examination revealed muscle weakness of the neck flexor and proximal muscles of four extremities. Serum myogenic enzymes including creatine kinase increased, and electromyography showed denervation potentials and MUPs were myogenic, which was compatible with polymyositis. Muscle biopsy indicated perivascular mononuclear cell infiltration and muscle fiber necrosis with cytoplasmic bodies and rimmed vacuoles in the muscle fibers. Complete blood cell counts revealed macrocytic normochromic anemia and bone marrow puncture disclosed marked hyperplasia of megakaryocytes, erythroblasts and myeloblasts, suggesting a refractory anemia type of MDS. In addition, skin biopsy showed chronic cutaneous vasculitis. Serum protein electrophoresis and immunoelectrophoresis revealed the presence of IgM gamma type monoclonal gammopathy. With immunosuppressive therapy, serum creatine kinase level was decreased. Since immunological abnormalities and the presence of autoimmune diseases have been reported in patients with MDS, both polymyositis and chronic cutaneous vasculitis in the present patient may be caused by the similar autoimmune mechanisms related to MDS.

Autoimmune Diseases↗

[A case of central alveolar hypoventilation syndrome associated with cerebral infarction].

Central alveolar hypoventilation syndrome (CAH), or Ondine's curse, is a very rare disease characterized by dysfunction of respiratory center in the brain stem. Here, we report a case of CAH associated with cerebral infarction. A 59-year-old man developed right facial sensory deficit at age 56. Then, the facial sensory deficit spread to the left side and dysarthria and dysphagia also developed. Since age 58, he often developed respiratory failure and consciousness disturbance. Arterial blood gas analysis revealed alveolar hypoventilation and respiratory acidosis. Disorders of peripheral organs such as lung, airway, thorax and neuromuscular diseases were ruled out. Brain MRI showed cerebral infarction in the brain stem. We diagnosed him as CAH associated with brain stem infarction.

Blood Gas Analysis↗

[A case of early onset cerebellar ataxia with hearing loss, mental disturbance and primary hypogonadism].

A 14-year-old girl, whose birth and developmental history were normal till the age of 7, was admitted to our hospital because of slowly progressive difficulties in walking, speaking and hearing. She also complained of absence of menstruation. She showed poor school records since the age of 7. On neurological examination, she showed limb and truncal ataxia. There was no nystagmus but slurred speech was found. Muscular power was good and her sensory system was normal. Tendon reflexes were equally present, and plantar reflexes were flexor. Bilateral moderate nerve deafness was also present. Mental deficiency was diagnosed on an intelligence test. Brain CT and MRI showed cerebellar atrophy. Gynecological examination revealed scanty pubic hair and small uterus. Karyotype was 46XX. Endocrinological studies demonstrated high level of FSH, low level of E2, and the normal response to pituitary stimulation with LHRH, indicating the existence of primary hypogonadism. Although the etiology of this multisystem disorder is unknown, it is possible that both nervous and endocrine disorders were genetically determined.

Adolescent↗