Search PubMed⌕ Search

Biomedical subjects

I Nonaka

Publications and source records attributed to I Nonaka.

At least 379 records · Page 21Linked to original sources
PubMed1987

Muscle involvement in pyruvate dehydrogenase complex (PDHC) deficiency.

Muscle biopsies from a 13-month-old female infant with a delay in developmental milestones, lactic acidosis and visual disturbance, and a 6 year-old female with frequent epileptic fits are described. Biochemical studies of biopsied muscles and skin fibroblasts demonstrated markedly decreased pyruvate dehydrogenase complex (PDHC) activity to about 16% of normal value. Muscle histochemistry in both patients showed disorganized intermyofibrillar networks containing large diformazan granules on NADH-TR, small angulated fibers with high nonspecific esterase (NSE) activity and basophilic fibers. Ragged-red fibers and increased lipid droplet accumulation were absent. Patient 1 had increased numbers of type 2C fibers (11.3%) and mild fiber type grouping. On electron microscopy, most mitochondria were nearly normal. There were focal aggregates of mildly enlarged mitochondria in the subsarcolemmal areas in both patients. Morphometric study showed that the mean mitochondrial size and the mitochondrial percentage of fiber volume were not significantly different amongst patients and normal controls.

Child↗
PubMed1987

Partial deficiency of subunits in complex I or IV of patients with mitochondrial myopathies.

Subunits of Complexes I, III, IV, and V from skeletal muscle mitochondria isolated from four patients with mitochondrial myopathies were analyzed by immunoblotting. A deficiency was observed in Complex I or IV, or in both. The patterns of deficiency of subunits of each complex were similar both in patients with deficiency of a single complex and in patients with combined deficiency of the two complexes. The deficiency of any of these subunits was only partial, and no abnormalities in the electrophoretic mobilities of the subunits were observed. These results suggest that the deficiency of Complex I or IV in these patients are based on similar molecular defects which lead to decreased levels of these subunits.

Adolescent↗
PubMed1987

Animal models utilized in research on muscular diseases in Japan.

A comparative study of human and animal muscular dystrophies revealed a number of differences in clinical symptoms and muscle pathology. In chicken muscular dystrophy (line 413), the white muscle was preferentially involved with striking vacuole formation in the sarcoplasm. Despite massive muscle fiber necrosis with phagocytosis which occurred in large groups in both hamsters (BIO 14.6) and mdx mouse dystrophies, the regenerating process compensated for the muscle fiber degeneration and resulted in no apparent clinical symptoms. Although the overall muscle pathology in dy mice (C57BL6J/dy+/dy+) including variation in fiber size, active fiber necrosis, interstitial fibrosis and progressive fatal course were very similar to those in human muscular dystrophy, dysmyelination at the anterior spinal roots in the mouse suggested the coexistence of neuropathic processes, which was probably involved in inducing muscle atrophy and weakness. A Japanese quail with slowly progressive muscle weakness was assumed to be a very important animal model for the adult onset type of human type II glycogenosis because there were very close morphological and biochemical similarities between the two species.

Animals↗
PubMed1986

Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes with acanthocytosis: a clinicopathological study of a unique case.

A case of a unique combination of mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like syndrome (MELAS) with acanthocytosis is reported. Neuropathological examination revealed pellagra-like change in Betz cells, brain-stem neurons and anterior horn cells as well as findings compatible with mitochondrial encephalomyopathies. Abnormal function of nicotinic acid-related enzymes could be the cause of the complicated clinicopathologic findings in this case. This is the first report of MELAS with acanthocytosis.

Acanthocytes↗
PubMed1986

Mitogenic heparin-binding lectin-like protein from cloned thymic myoid cells.

A mitogenic heparin-binding (reactive) lectin-like protein (HBP) was purified from the extract of a cloned rat thymic myoid cell R615B2 by a one-step procedure of affinity chromatography on a heparin--Sepharose CL-6B column. Four distinct peptide bands with molecular weights of 10,000, 13,000, 13,700, and 14,600 were detected on SDS-polyacrylamide gel electrophoresis. This protein is mitogenic at concentrations of as low as 1.1-70.0 ng/ml for peanut lectin-nonagglutinated thymocytes and splenocytes from euthymic mice and rats but not for splenocytes from nude mice. These results indicate that thymic myoid cell-derived HBP is an important signal for one particular step in T-cell differentiation.

Animals↗
PubMed1986

Hereditary peroneal muscular atrophy in the mouse: an experimental model for congenital contractures (arthrogryposis).

A new mutant, peroneal muscular atrophy (pma) mouse in CF#1 strain has an autosomal recessively inherited equinovarus (club foot deformity) of the hind legs because of the absence of the common peroneal nerve branch of the sciatic nerve. We found the peroneal muscles were hypoplastic with histochemical and electron microscopic characteristics of fetal muscle. The anterior horn cells in the spinal cord were not reduced in number and they appeared to be normal. The density and size of the myelinated fibers in the anterior spinal roots of L3, L4, and L5 and the sciatic nerve in the affected side were not different from those in the unaffected. Therefore, the absence of the common peroneal nerve in the pma mouse is thought to result from the misdirection of these nerve bundles into other peripheral nerves. As the anomalous condition was present at birth with no progression, the pma mouse may be an experimental model for the study of arthrogryposis multiplex congenita or club foot deformity, and may lead to the understanding of the muscle and nerve interaction during development.

Animals↗
PubMed1986

High AMP deaminase activity in rimmed vacuoles of skeletal muscle.

Localized high AMP deaminase activity was found in the rimmed vacuoles of skeletal muscles in acid maltase deficiency, distal myopathy with rimmed vacuole formation, and experimental chloroquine myopathy on histochemical staining. Acid phosphatase activity was also increased in and around these vacuoles, but the vacuoles were negative for other histochemical stainings such as with NADH-tetrazolium reductase, ATPase and phosphorylase. These findings suggest that AMP deaminase is bound to membranous components in addition to myosin in skeletal muscle.

AMP Deaminase↗
PubMed1986

Muscle involvement in a case of oculocutaneous albinism.

A 2-month-old girl with tyrosinase-positive oculocutaneous albinism (OCA) and severe muscle hypotonia is reported. She was admitted to our hospital because of poor sucking and poor weight gain. On physical examination she was found to have generalized muscle weakness and multiple anomalies including deafness, mental retardation, cataracta and a high-arched palate. A muscle biopsy showed marked variation in fiber size with bimodal distribution, suggesting a neuropathic process. Since electromyography showed a myopathic pattern, CK was definitely elevated and muscle histologic examination did not show any denervation of the type found in Werdnig-Hoffmann disease, the present disorder was assumed to be caused either by hardly developed motoneurons or by abnormal interaction between muscles and nerves.

Adenosine Triphosphatases↗
PubMed1986

Biochemical aspects of bupivacaine-induced acute muscle degradation.

A single injection of a local anaesthetic, bupivacaine, into the soleus muscle of adult rat has a severe mytoxic effect, i.e. rapid dissolution of myofilaments and degradation of myofibrillar proteins shortly after injection. Increased lysosomal enzymes were observed in homogenates of affected muscle. The activity of potent proteolytic enzyme, cathepsins B and L (assayed against a new synthetic substrate succinyl-Tyr-Met-naphthylamide), gradually increased and reached a plateau value that was 11-fold greater than the control 48 h after bupivacaine injection. The chronological change in the activity of cathepsins B and L was reflected in the myofibrillar protein pattern in bupivacaine-treated muscle. To determine whether the increase in lysosomal peptide hydrolases is due to activation of muscle lysosomes or not, mononuclear cells were separated from both injected and control muscles. The activity of cathepsins B and L in the lysate from injured muscle was 180-fold higher than the control. Affinity-purified antibody was used to study the intracellular localization of cathepsin B by immunohistochemical procedures. The results were consistent with the biochemical observation that the main source of cathepsin B in muscle homogenates was infiltrated mononuclear cells. Therefore, we conclude that the increased lysosomal enzymes may be derived mainly from mononuclear cells (macrophages), not from muscle lysosomes, in bupivacaine-induced acute muscle degeneration.

Animals↗
PubMed1986

Abnormal increases of lysosomal cysteinine proteinases in rimmed vacuoles in the skeletal muscle.

Skeletal muscle obtained from a patient with distal myopathy with rimmed vacuole formation (DMRV) was examined by a new direct labeled antibody enzyme method of immunohistochemistry. Abnormal increases of cathepsins B and H, capable of degrading the myofibrillar proteins, were demonstrated to be localized at the site of vacuoles and other intramyofibral portions and not to be associated with concomitant increases of their endogenous inhibitors. Autodigestion by these intramyofibral lysosomal proteinases may be of major importance in focal destruction of myofibers and formation of vacuoles, because no myofiber necrosis with invasion of macrophages, overt myositis, and neuropathy was seen in the muscle. These findings provide the first reasonable explanation of myofibral breakdown and atrophy in DMRV, and should be helpful in further studies on the mechanism of myofibral breakdown in various vacuolar myopathies and other myopathies of so far unknown pathogenesis.

Adult↗