Therapeutic trial with protease inhibitor (Leupeptin) in chicken muscular dystrophy

Summary For the purpose of observing the therapeutic benefit of protease inhibitors for progressive muscular dystrophy, a large quantity of doses of leupeptin of 10 mg/kg/day and 50 mg/kg/day were administered i.p. to male chickens afflicted with hereditary muscular dystrophy (line 413) for 4 months starting on the 7th day ex ovo. No clinical improvement was identified in physical ability as a result of the examination by flip test, and creatine kinase (CK) values. The number of necrotic fibers in the pectoralis superficialis (PS) muscle which is known to be preferentially damaged in dystrophic chicken, did not decrease significantly in the birds treated with 10 mg leupeptin/kg/day (number of necrotic fibers; 47.7/mm²) and 50 mg/kg/day (46.4/mm²) as compared to that of the untreated ones (43.2/mm²). A morphometric analysis of fiber diameter distribution also showed no statistical difference between the treated and untreated birds.In the second group, 10 mg leupeptin/kg and a combination of leupeptin and bestatin of 10 mg/kg each were injected directly into the left lower half of the PS muscle three times a week for 4 months. Necrotic fibers were still present in the injected site, remote area of the left upper PS muscle treated with leupeptin (52.7/mm²), leupeptin and bestatin (52.2/mm²), and contralateral right upper PS muscle (41.6 and 53.5/mm², respectively). The number of necrotic fibers in treated muscles was again not significantly different from that in untreated dystrophic ones (39.6/mm²). In fiber diameter analysis, no statistical difference was recognized between the treated and untreated dystrophic muscles.Partly supported by a grant-in-aid for New Drug Development Research from the Ministry of Health and Welfare, Japan     

Arthrogryposis multiplex congenita: histochemical study of biopsied muscles

Morphometric analysis was performed after histochemical staining on 12 biopsied muscles of the affected limbs from 12 patients with arthrogryposis multiplex congenita. Except for one muscle, samples demonstrated variation in fiber size associated with abnormal fiber type distribution suggesting abnormal innervation: large groups of atrophic fibers in one muscle, either type 1 or 2 fiber predominance with occasional fiber type grouping in five, a complete lack of type 2 fibers in one, type one fiber atrophy in one, both type 2A and 2B fiber atrophy in two, and increased number of type 2C fibers in four. In most patients with arthrogryposis multiplex congenita, a defect in neural influence on the developing muscles may be responsible for the absence or maldevelopment of some muscle groups. Underdeveloped muscles are then assumed to induce imbalance of agonists and antagonists resulting in permanent contractures.     

IMMUNOLOGICAL STUDIES OF ONCHOCERCIASIS IN GUATEMALA

The serum levels of the four immunoglobulins, IgG, IgA, IgM and IgE, in Guatemalan onchocerciasis patients were determined quantitatively using a laser immunoassay system or radioimmunosorbent test. The IgG and IgE levels in Guatemalan onchocerciasis patients positive for Onchocerca volvulus microfilariae were significantly higher than the levels in Guatemalan controls negative for microfilariae and in healthy Japanese controls. But, no differences in the levels of IgA and IgM were obtained between the Guatemalan onchocerciasis patient group and the two control groups.     

The fundamental architecture of the microvasculature of the basal ganglia and changes in senility

The microvascular architecture of the basal ganglia of human brains was studied on diaphanized specimens after intravascular barium injection and vascular stains. Observation by scanning electron microscope was also performed. The putamen and caudate nucieus showed dense capillary networks. Less dense capillary networks were noted in the capsula interna. The capillary network in the globus pallidus was less dense than that in the striatum but denser than that in the capsula interna. The lenticulostriate arteries ran through the putamen, across the internal capsule and reached the caudate nucleus. Though the arterial branches running within the putamen had many small branches, branching was minimal while crossing the capsula interna and began showing rich ramification again when they reached the caudate nucleus. There were retrograde ramifications in the putamen and caudate nucleus. They appeared to play a significant role in the regulation of blood pressure and are considered to play some role in the occurrence of circulatory disturbances which are prone to involve these structures. The fountain-like ramifications were seen in the putamen and caudate nucleus, but their function is not clear. In the brains of senile patients, intertwining of the arterial blood vessels was noted in the fountain-like rami. This structure began to appear in the patients over the age of 50. While the etiology of the intertwining of the arteries remains unknown, its increasing frequency with age supports a hypothesis that this represents a phenomenon correlated with aging or concomitant brain atrophy.     

Progressive Muscular Dystrophy with Particular Reference to Muscle Regeneration

In various progressive muscular dystrophies (PMD), there were a number of fibers with histological and histochemical characteristics of regenerating fibers. With a morphometric analysis in diseased muscles, an identification of type 2C fiber on ATPase stain was the most simple and reliable method for fiber type evaluation. The type 2C fiber comprised 16.5% in Duchenne and 27.5% in Fukuyama type congenital MD, suggesting an active regenerating process taking place in both diseases. Regenerative capacity of muscle fibers after experimental damage to dystrophic chicken and mdx mouse muscles was similar to those seen in nondystrophic control muscles. From the above results, we speculate that a certain environmental factor such as interstitial fibrosis seems to play a major role in delaying regeneration in dystrophic muscles.     

Tau protein immunoreactivity in muscle fibers with rimmed vacuoles differs from that in regenerating muscle fibers

Summary To determine whether tau protein found in muscle fibers with rimmed vacuoles and in regenerating fibers was phosphorylated, we examined eight muscle biopsy samples containing rimmed vacuoles (from five patients with distal myopathy with rimmed vacuole formation and three patients with inclusion body myositis) and three muscle biopsy samples from patients with Duchenne muscular dystrophy containing numerous regenerating fibers. Although both rimmed vacuolated and regenerating fibers had increased immunoreactivity against tubulin and tau protein, tau protein in the former was more highly phosphorylated than that in the latter. While very few microtubules in muscle fibers with rimmed vacuoles were recognizable by electron microscopy, regenerating fibers, especially immature ones, contained numerous microtubules. Since tau protein found in vacuolated fibers is hyperphosphorylated, it can be considered to have reduced ability to bind tubulin molecules. Thus, the tau protein cannot stabilize microtubules, resulting in their depolymerization even in the presence of tubulin molecules.     

Primary Intestinal Myopathy, a Cause of Chronic Idiopathic Intestinal Pseudoobstruction Syndrome (Cips): Clinicopathological Studies of Seven Cases in Children

Clinicopathological data on seven instances of primary intestinal myopathy in children are reported. The ages of the patients ranged from eleven months to thirteen years. A persistent intestinal obstruction was the main and constant clinical feature. An ineffective intestinal propulsion was documented on manometric studies. Various urological abnormalities were present in three cases. One patient died and six survive but are dependent on enteral and parenteral nutrition. The morphological findings consisted of degenerative changes involving the muscular layers of the intestinal wall. These changes varied from cytoplasmic vacuolation to definite atrophy and disappearance of the muscular fibers. An extensive interstitial fibrosis underlined these atrophic changes in the late stages of the disease.

A familial history was identified in three cases, one consistent with an autosomal dominant transmission.     

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.