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Unlabelled: In the advanced stage of dystrophinopathy, cardiac dysfunction is a serious complication for prognosis. Recently, an angiotensin converting enzyme (ACE), which converts angiotensin (A) 1 to A 2, has been reported to be effective for cardiac insufficiency. The A 2 is produced more dominantly in the path via the production of a neutral serine protease, chymase (MW 25,000), secreted from the mast cell. We have observed localization of chymase in diseased human skeletal muscle tissues, and evaluated its clinical significance. The frozen muscle biopsied specimens from 91 neuromuscular disorders (muscular dystrophies, inflammatory myopathies and neurogenic muscular disorders) were stained by using monoclonal antibody against the chymase, and the positive cells in a whole sectional field were counted. In the serial sections, we also performed routine histochemistry and immunostainings of immunological markers (CD4, CD8 and others) as well as the apoptotic proteins for comparison., Results: The chymase-positive mast cells were scattered mainly in the endomysium, partly in the perimysium and around small vessels. Although the positivity was not disease specific, more numerous strongly positive cells were observed in dystrophinopathy and inflammatory myopathies, but less in myotonic dystrophy and neurogenic muscle disorders. In the normal control muscle, however, strongly positive cells appeared less frequently than in the above mentioned diseased muscles. The chymase-positive cells partly corresponded to the ubiquitin-positive ones, but perforin, granzyme A, Fas and Bcl-2 did not. In conclusion, the chymase-positive mast cell may play a primary or secondary role in the diseased muscle, and their more abundant appearance in dystrophinopathy and some other myopathies suggest the effectiveness of an ACE blocker, an anti-chymase drug.

Immunostaining of the Fas antigen using the anti-Fas IgG1 antibody was performed on biopsied human diseased muscles. The immunostaining showed negative results in the control muscles. In dystrophinopathy [DMD and BMD], positivity was seen mainly in type 2 fibers with no correlation to the opaque fibers and histochemical Ca2+ loading fibers in DMD. In DMD carriers, a relative correlation was seen between dystrophin-negative and Fas-positive fibers. In distal myopathy with rimmed vacuoles, fibers with positive staining in the vacuoles but negative in their membranes were seen at high frequency. In FSH, a very low frequency of positivity was seen. And in myotonic dystrophy, positivity was seen in the type 2 fibers containing the internal nuclei. In inflammatory myopathies, strong positivity was seen in the medium size fibers, and mild to moderate positivity in the fibers facing the perimysium. In neurogenic muscular disorders, fibers with concave borders or highly atrophic fibers showed Fas-positivity. In conclusion, there was no disease-specific Fas reaction in the human pathologic muscle samples, but the high positivity was apparent in some myopathies. This fact of Fas antigen would reflect a pathologic state in the skeletal muscle.

A statistical analysis of mitochondrial abnormality of aging in human skeletal muscle fibers was performed. Sixty one muscle samples were obtained from patients with acute medical illness autopsied strictly within 2 hours after death, or with orthopedic or surgical diseases biopsied with informed consents. The patients aged from 16 to 89, averaging 58 +/- 21 years in males and 21 to 92, averaging 55 +/- 20 years in females. Sections were stained by modified Gomori's trichrome, succinate dehydrogenase and cytochrome c oxidase-negative [CCO(-)] fibers approximately in 10,000 fibers in each muscle were evaluated. Both RRF and CCO (-) fibers were not observed below the fourth decade, but sequentially increased with age, especially after the seventh decade. The incidence of CCO (-) fibers was higher than that of RRF. RRF did not necessarily correspond to CCO (-) fibers. The present quantitative pathological result is a useful tool to evaluate the mitochondrial function in fresh human skeletal muscles by the age.

A patient with chronic progressive external ophthalmoplegia (CPEO) who had abundant cytoplasmic bodies in muscle fibers and a deletion of mitochondrial DNA is reported. The patient was a 26-year-old male suffering from ophthalmoplegia from age 21. He had a marfanoid skeletal abnormality and perceptive hearing loss, but had neither retinopathy, ataxia, nor dementia. In the mitochondria isolated from the biopsied skeletal muscle, NADH-ubiquinone oxidoreductase activity was slightly decreased, succinate-cytochrome c reductase activity was slightly increased, and cytochrome c oxidase activity remained normal. Southern blot analysis of the muscle DNA identified heteroplasmy composed of a normal-sized mitochondrial DNA and a mutant mitochondrial DNA with a 4.2-kilobase deletion. The PCR plus S1 analysis showed that the deletion extended from nucleotide position 7860 +/- 60 to 12,090 +/- 70. The histological studies of the biopsied muscle revealed ragged-red fibers and cytochrome c oxidase-negative fibers in 15.7% and 18.6% of the muscle fibers, respectively. Other conspicuous histological change was abundant cytoplasmic bodies surrounded by clusters of abnormal mitochondria. The cytoplasmic bodies were found preferentially in type 1 fibers, and exclusively in cytochrome c oxidase-negative fibers and in ragged-red fibers. Focal existence of cytoplasmic bodies in muscle fibers with abnormal mitochondria suggests that segregated distribution of the abnormal mitochondria with deleted mitochondrial DNA is involved in the pathogenesis of cytoplasmic bodies.

We analysed the patterns of skeletal muscular involvement in 18 patients with bulbar-spinal muscular atrophy (BSMA) of the Kennedy-Alter-Sung type by using the computed tomographic scanner. Fatty infiltrations were prominent in various skeletal muscles of extremities and trunk, and its degree was severe in the following numerical orders; the gluteal muscles, flexors of the thighs, flexors of the lower extremities, extensors and the adductors of the thighs, the paraspinal muscles, and extensors of the lower extremities. There was statistically significant correlation between fatty infiltrations in flexors of the lower extremities and duration of illness. And were noted findings that the skeletal muscle lesion progressed with the preserved fasciae and sectional areas, fatty infiltrations in the lower extremities were more conspicuous in flexors than in extensors, and compensatory hypertrophic muscles in the thigh were apparent in 50% of cases. In conclusions, the computed tomographic analyses on skeletal muscle of BSMA may be useful to detect distributions, progression of the muscle lesion, in addition to a profile of the myopathic alterations of the disease.

We have demonstrated the histochemical fiber types of human skeletal muscle in paraffin sections by the immunohistochemical method, together with compatible observations previously made in frozen sections that carbonic anhydrase III is mainly localized in type 1 fibers (Shima et al. 1983), and muscle-specific enolase in type 2 fibers (Ibi et al. 1983). This method is useful to analyze the fiber types when frozen muscle samples at biopsy or autopsy cannot be obtained.

We have localized beta-enolase activity in human skeletal muscle fiber using the immunohistochemical method (two-step method). The first immunoreagent was rabbit anti-human beta-enolase serum raised in New Zealand white rabbit, and the second was peroxidase conjugated staphylococcal protein A. The immunohistochemical reaction for beta-enolase was noted higher in type 2 fiber, which demonstrates the low oxidative and high glycolytic enzyme activity, than in type 1 fiber.