Search PubMed⌕ Search

Biomedical subjects

I Nonaka

Publications and source records attributed to I Nonaka.

At least 451 records · Page 25Linked to original sources
PubMed1981

A clinical and histological study of Ullrich's disease (congenital atonic-sclerotic muscular dystrophy).

Clinical characteristics recognized in five cases with Ullrich's disease included muscle weakness and wasting, striking contracture of proximal (sclerotic) joints and hyperflexibility of distal (atonic) joints since an early infantile stage, and slowly progressive course. The biopsied muscles demonstrated myopathic changes including a remarkable variation in fiber size, notably proliferated endomysial connective tissue, increased myofibers with centralized nuclei and a few necrotic fibers with active phagocytosis. On histochemical examination, no specific intracytoplasmic structural abnormalities such as nemaline bodies, cores and myotubes were recognized. Although both type 1 and 2 fibers were distributed in checkerboard pattern in most muscle fascicles, type 1 fiber predominance or type 2 fiber deficiency was common in severely damaged muscles, suggesting the presence of some kind of neural influence exerting on the myopathic process as the disease progressed. Since it still remains uncertain whether this disorder belongs to the muscular dystrophies, or to other neuromuscular or mesodermal diseases, we would rather label it Ullrich's disease then Ullrich's muscular "dystrophy" until its pathogenesis becomes clear.

Adolescent↗
PubMed1980

Anastomoses of transverse tubules with terminal cisternae in polymyositis.

Abnormal transverse or T tubules spatially continuous with sarcoplasmic reticulum (SR), as visualized with a lanthanum (La) tracer, were found in biopsy specimens from nine patients with polymyositis whose serum enzyme (creatine phosphokinase [CPK]) levels were elevated before the time of biopsy. On comparison with the T system in more than 50 control subjects without CPK elevation, it became apparent that presumed anastomoses of T tubules with SR were the most consistent anatomical correlates of the enzyme leakage. Two types of anastomoses were seen on the basis of passage of La: first, early segmental dilation of T tubules and perpendicular continuations with SR; and second, focal proliferation of T tubules forming "T tubule networks" and then anastomosing with SR at the periphery of the networks. The latter is considered to be a concurrent repair process for the injured triads. Lanthanum did not penetrate freely through the plasma membrane of necrotized muscle fibers. It is concluded that junctional sites between T tubules and SR may be the primary sites of leakage of sarcoplasmic enzymes in polymyositis.

Adolescent↗
PubMed1980

Calcium-activated neutral protease. Its localization in the myofibril, especially at the Z-band.

Calcium-activated neutral protease (CANP) was demonstrated in myofibrils, especially at the Z-band in chicken glycerinated myofibrils, by an immunofluorescent method. The amount of CANP bound to myofibrils was approximately 4 percent of that contained in the whole muscle homogenate. No immunological difference was recognized between the myofibril-bound CANP and the soluble one when examined by Ouchterlony's immunodiffusion analysis. A possible role of myofilbril-bound CANP in the physiological turnover of the myofibrillar proteins is discussed.

Animals↗
PubMed1978

Werdnig-Hoffmann disease: proposal of a pathogenetic mechanism.

Light and electron microscopic study and morphometric analysis were performed on the spinal cords and roots from six cases of acute Werdnig-Hoffmann disease and four control cases, in search of the pathogenesis of the selective motor neuron changes considered primarily responsible for Werdnig-Hoffman disease. This investigation posits a centrifugal traction mechanism based upon the discovery of cylindrical outgrowths of glial bundles, selective loss of large myelinated fibers, and axonal degeneration in the proximal portion of anterior spinal roots (and to a lesser extent in posterior spinal roots) in all six disease cases. This traction mechanism exerts principally upon anterior spinal nerve roots and can account for morphologic and morphometric data characteristically ascribed to Werdnig-Hoffmann disease.

Axons↗
PubMed1977

Satellite cells and muscle regeneration in diseased human skeletal muscles.

By virtue of the lanthanum nitrate staining technique applied to biopsied muscle we are able to demonstrate interaction between satellite cells and parent myofibers, as well as development of premyocytes from activated satellite cells. The process of regeneration in diseased muscle appears to differ from that described in experimental myogenesis. Transformation of activated satellite cells to two types of premyocytes in the process of muscle regeneration seems to rely primarily on the state of innervation and recovery rate of the parent cell after injury. Activated satellite cells are characterized morphologically by proliferation of caveolae, first on the parent fiber side, and early T-tubule and myofilament formation and central displacement. In diseased human muscle the satellite cells appear to play significant roles in muscle regeneration both as a source of reinforcement for failing metabolism in the parent cell and as potential replacements for the necrotic segment of the parent cell. This study also demonstrates that the satellite cells are capable of developing into independent myocytes which may fuse with or replace the parent cell, dependent upon the type and extent of the injury sustained. Abnormal fusion among premyocytes or with their parent fiber, resulting in formation of split-or ring-fibers, becomes conceivable when both innervation and recovery from the injury of the parent cell are delayed. Thus, myotube formation, characteristic of usual myogenesis, seldom takes place in the regenerative process instituted by satellite cells in diseased human skeletal muscles.

Humans↗