Search PubMed⌕ Search

Biomedical subjects

I Nonaka

Publications and source records attributed to I Nonaka.

At least 361 records · Page 20Linked to original sources
PubMed1988

Shaking rat Kawasaki (SRK): a new neurological mutant rat in the Wistar strain.

Shaking rat Kawasaki (SRK), a newly discovered neurological mutant rat in the Wistar strain, is described. The abnormalities of SRK rats are transmitted as an autosomal recessive trait. The neurological signs are shaking of the body and an ataxic-paretic gait from day 10 postnatal. The affected rats survive for about 1 month. Macroscopically, the cerebellum is small and frequently the vermis and paraflocculus lacking. The most conspicuous histological finding in the central nervous system is malposition of the neurons in the cerebral cortex, hippocampus and cerebellum. Myelination and synapse formation are intact. Abnormal myelinated fibers are present in the molecular layer of the cerebral cortex and in the central gray matter of the spinal cord. These morphological abnormalities resemble those reported in the reeler mutant mouse. SRK rats are another good animal model of human congenital malformations with neuronal migration disorders.

Animals↗
PubMed1988

Muscle pathology in cytochrome c oxidase deficiency.

Muscle biopsies from 16 patients with cytochrome c oxidase (CCO) deficiency were examined morphologically. Two siblings had the fatal infantile form. The muscle of the older sister at the age of 5 months had numerous ragged-red fibers (RRF) and increased numbers of lipid droplets; at 28 days the brother had no RRF suggesting that the RRF formed later than 28 days. The muscle pathology in two patients with the benign infantile form improved as they grew older; numbers of RRF, lipid droplets and glycogen particles decreased and CCO activity increased in the second biopsy. In the encephalomyopathic form, RRF were seen in 5 of 12 muscles mostly in patients more than 6 years of age. Muscle spindles and blood vessel walls in the biopsies from three patients with rapid clinical aggravation had no CCO activity, suggesting that enzyme activity differed from tissue to tissue (tissue specificity).

Adolescent↗
PubMed1988

Variability in the activity of respiratory chain enzymes in mitochondrial myopathies.

Four patients with mitochondrial abnormality had multiple muscle biopsies at several year intervals during which respiratory chain enzyme activities were shown to be quite variable. In three patients, progression of the disease paralleled the decrease in respiratory chain enzyme activity. In one patient, the clinical and pathological findings improved with age as is seen in the benign infantile form of cytochrome c oxidase (CCO) deficiency. The variability in these mitochondrial disorders may result from the varied proportions of normal and abnormal mitochondria in the muscle cells in which the mitochondria are said to be randomly replicated from numerous mitochondrial DNA copies.

Adolescent↗
PubMed1988

Skeletal muscle pathology in chronic progressive external ophthalmoplegia with ragged-red fibers.

Histochemical investigations were carried out on skeletal muscle biopsies from ten patients with chronic progressive external ophthalmoplegia with ragged-red fibers (RRF). In addition to the RRF, mild myopathic change consisting of variation in size of both type 1 and 2 fibers was seen in all patients, as well as neuropathic change in eight. Scattered fibers with absent cytochrome c oxidase (CCO) activity (focal deficiency) were seen in all patients. In serial sections, CCO deficiency did not always occupy the entire length of a fiber but was localized segmentally to regions measuring several hundred micrometers in length, suggesting the heterogeneity of CCO activity even in the same fiber.

Adult↗
PubMed1988

Internodal Schwann cell fingers in the ventral spinal roots in mice: incidence and relationship to the diameter of myelinated fibers.

Internodal Schwann cell fingers were present in the lumbar, cervical, and thoracic spinal roots of adult mice at the age of 3 months, but they were not recognized in five mice examined at the age of 3 weeks. In the L4 ventral roots of ICR mice aged 3 months, the incidence of internodal Schwann cell fingers was 0.79% at the central-peripheral transitional zone and 2.43% at the distal regions, respectively. The ratio of axon diameter to total fiber diameter of myelinated fibers with internodal Schwann cell fingers was lower than that of fibers without them. Therefore, we conclude that internodal Schwann cell fingers are probably related to the developmental increase in the thickness of the myelin sheaths in the ventral spinal roots at all levels of the spinal cord.

Animals↗
PubMed1988

A morphometric study of muscle mitochondria in cytochrome c oxidase deficiency.

Quantitative analysis of mitochondrial size and its percentage of total fibre volume in different muscle fibre types was performed on biceps brachii muscles of controls aged from 9 months to 10 years, and patients aged from 8 months to 14 years, with cytochrome c oxidase (CCO) deficiency confirmed by both histochemical and biochemical analyses. The disease was classified into 2 subgroups: one not containing ragged-red fibres (RRF) (group I), and one containing RRF (group II). Relationship between type 1 and 2 fibres in mitochondrial size and percentages of total fibre volume showed significant differences in the controls and group I. A comparison of the controls and group I did not show significant differences in mitochondrial size, but abnormally enlarged mitochondria were occasionally observed in the latter. In group I, statistical differences were observed in mitochondrial percentage of total fibre volume, though these differences remained in the control range, suggesting the presence of mild morphological changes in mitochondria on electron microscopy. In group II, mitochondrial size and its percentage of total fibre volume were markedly increased in both type 1 and 2 fibres, with no statistical differences observed between the 2 fibre types.

Child↗
PubMed1988

Perifascicular atrophic fibers in childhood dermatomyositis with particular reference to mitochondrial changes.

Ten of 17 muscle biopsy specimens from 15 patients with childhood dermatomyositis (DM) showed distinct perifascicular atrophy. The atrophic fibers showed the following characteristics: (1) decreased cytochrome c oxidase (CCO) activity, (2) rare positive reaction with acridine orange (AO) staining, (3) type 2C reaction in 7.9% (0.4-17.5%) of the fibers, (4) an increased number of activated satellite cells, (5) mitochondria which were increased in number but decreased in size, (6) a significantly decreased CCO activity in isolated mitochondria (51.6 +/- 30.3 nmol/min per mg mitochondrial protein) as compared with that in the controls (103.6 +/- 41.5). The major pathogenetic mechanism in muscles in childhood DM is thought to be ischemia due to involvement of the microvasculature. The presence of type 2C fibers and increased numbers of activated satellite cells reflect a focal repair process taking place concomitantly in the damaged myofibers. Mitochondrial enzyme defect, especially CCO deficiency is present not only in genetic disorders with mitochondrial involvement but in other neuromuscular disorders including inflammatory myopathies.

Age Factors↗
PubMed1988

Semi-quantitative immunohistochemical studies on Thy-1 antigen expressed by thymic myoid cells.

Thy-1 antigen expression in the rat thymic myoid cell line R615B2 (Thy-1(+] and R613Ad (Thy-1(-] was studied with a semi-quantitative immunohistochemical assay without disrupting the cell cultures. With this assay, the quantity of Thy-1 antigen on R615B2 cells was detected separately in the cytoplasm and on the cell surface by the use of appropriate fixatives such as chilled ethanol and methanol + 0.3% H2O2. Extracellular Thy-1 antigen was also found in the culture supernatant of R615B2 cells. More than half of extracellular Thy-1 antigen remained in the supernatant even after 100,000 X g centrifugation. No form of Thy-1 antigen was detected at significant levels in R613Ad cells.

Animals↗
PubMed1988

Intraepidermal pilar epithelioma: a new dermatopathologic interpretation of a skin tumor.

An intraepidermally developed epithelial cell tumor, forming multiple nests, was examined to identify its cytologic characteristics. Histochemically, the tumor cells contained neither glycogen nor lipid substance. By N-(7-dimethylamino-3-methyl-4-coumarinyl)maleimide staining, the cytoplasm of the tumor cells in the periphery of each nest was rich in SH groups but not in SS linkages, whereas centrally located homogeneous tumor cells contained SS diffusely but no SH. The tumor cells showed no activity of phosphorylase and a weak activity of succinic dehydrogenase. Immunohistochemically, antihair keratin monoclonal antibodies specific for hair cells decorated the tumor cells, but carcinoembryonic antigen staining showed no positivity. Ultrastructurally, the tumor cells underwent a keratinization forming a fingerprint pattern of keratin filaments; however, membrane-coating granules and marginal bands were not formed. These intraepidermal tumor cells may have cytologic natures similar to those of hair cortical cells. The term intraepidermal pilar epithelioma is proposed as a diagnosis for this tumor.

Cell Differentiation↗
PubMed1988

Defects in muscle fiber growth in fatal infantile cytochrome c oxidase deficiency.

In addition to numerous ragged-red fibers in the muscle from a female infant with fetal infantile cytochrome c oxidase deficiency, the muscle fibers were small in caliber with electron microscopic characteristics of immaturity; the satellite cells were significantly increased in number to 31.3% as compared with those in controls, 8.4 +/- 1.6% (p less than 0.001). In the culture system, the biopsied muscle showed markedly reduced growth despite the presence of numerous satellite cells which are known to act as myoblasts in muscle regeneration, and formed fewer numbers of myotubes containing poorly organized myofibrils and mitochondria with no cytochrome c oxidase activity. A defect in myogenesis and a paucity in repair process in severe form may account for the progressive course and a fatal outcome.

Biopsy↗
PubMed1988

Atypical form of Menkes kinky hair disease with mitochondrial NADH-CoQ reductase deficiency.

A male infant with an atypical form of Menkes kinky hair disease showed mitochondrial NADH-CoQ reductase (complex I) deficiency in a femoris muscle biopsy. His clinical features consisted of hypotonicity of the upper limbs, hyper-reflexia of the lower extremities, abnormal hair and fine myoclonic movement of the hands. The serum levels of copper and ceruloplasmin were just below normal range, and the copper concentration in fibroblastic cells was much increased (101.2 ng/mg of protein). The occurrence of this case suggests that there may be a mild form of Menkes disease with a NADH-CoQ reductase deficiency or other mitochondrial enzyme defects.

Atrophy↗
PubMed1987

Acid maltase deficiency in the Japanese quail; early morphological event in skeletal muscle.

The skeletal muscle of Japanese quails with acid maltase deficiency (AMD) was studied morphologically at various developmental stages, from the 16th embryonal day up to 3 months after hatching. Membrane-bound glycogen particles began to appear in the affected skeletal muscle at the 16th embryonal day. In normal embryonic muscles, a certain amount of free glycogen particles was observed but they were not membrane-bound. Therefore, this is the earliest morphological event in the muscle of Japanese quails with AMD. In muscle at 3 weeks after hatching, the initial focal degeneration of myofibrils was recognizable but it was not associated with autophagic vacuoles. Quails with AMD developed muscle weakness and difficulty in lifting their wings at about 3 months after hatching: then numerous autophagic vacuoles were present. The formation of large autophagic vacuoles followed by fiber loss and fatty replacement seemed to contribute to the progressive muscle weakness. The study of Japanese quail with AMD will greatly facilitate the elucidation of the pathogenetic mechanism and is also a useful model for therapeutic trials in human AMD.

Animals↗
PubMed1987

Muscle fiber growth and necrosis in dystrophic muscles: a comparative study between dy and mdx mice.

Histopathological and morphometric studies of murine dystrophic muscles in the early postnatal period were performed. In dy mice, obtained by in vitro fertilization, scattered necrotic fibers were noted at 10 days of age followed by poorly compensated regeneration leading to muscle fiber loss, marked variation in fiber size, and fibrous and adipose tissue proliferation. In mdx mice, clusters of necrotic muscle fibers seen at 10-15 days were followed by well compensated regeneration with little fibrosis. There appeared to be no delay in muscle fiber growth and fiber type differentiation in both dy and mdx mice up to 10 days of age since there was no distinct difference in muscle fiber size, fiber type differentiation and the incidence of myosatellite cells between dystrophic muscles and those from age-matched control mice. Muscle fibers appeared to undergo necrosis only when they had reached a certain stage of maturation since at early stages of development or regeneration they rarely became necrotic. The difference in clinical symptoms between dy and mdx mice may result from differences in their regenerative response to necrosis.

Animals↗
PubMed1987

Congenital myotonic dystrophy. Changes in muscle pathology with ageing.

Undifferentiated type 2C fibers and satellite cells were increased in number in younger patients with congenital myotonic dystrophy (CMD) indicating immaturity in muscle fiber growth. The changes found in a 38-year-old man with CMD were identical to those described in late onset myotonic dystrophy. Type 1 fibers were found to become predominant with age. This suggests that in this disorder fiber type transformation progresses with age, presumably due to abnormal neural influences or aberrant sarcolemmal responses.

Adult↗
PubMed1987

Two cases of NADH-coenzyme Q reductase deficiency: relationship to MELAS syndrome.

Muscle biopsy specimens from two patients with MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes) were studied biochemically. 14CO2 production rates from (1-14C)pyruvate, (U-14C)malate, and (1-14C)2-ketoglutarate were all decreased in intact mitochondria in both patients. Rotenone-sensitive NADH cytochrome c reductase activities were decreased to 8% (patient 1) and 6% (patient 2) of control values; succinate cytochrome c reductase and cytochrome c oxidase values were within normal limits. These results indicate that both patients have a defect of NADH-CoQ reductase of the respiratory chain and that MELAS can be brought about by a defect of NADH-CoQ reductase.

Acidosis, Lactic↗