Immunostaining of dystrophin and utrophin in skeletal muscle of dystrophinopathies

Immunostaining of biopsied skeletal muscle of 4 Duchenne (DMD), 12 Becker muscular dystrophy (BMD) and 3 DMD carriers' was performed using monoclonal antibodies against dystrophin and utrophin. In DMD, dystrophin-negative staining was observed except for revertant fibers which showed different stain patterns for each antibody. In 7 BMDs, there was faint/patchy stain in cases of deletion between exons 45-52, while in one case there was deletion between exons 12-17 and no stain was noted relevant to the deletion site. Moreover, in 2 cases of undetectable deletion, antibodies which recognize a terminal portion of the C-terminal domain revealed the absent stain. In DMD, the utrophin-positive fibers corresponded to dystrophin-negative fibers. In BMD, this relationship did not necessarily occur in each fiber. In DMD carriers, a cluster of dystrophin-negative fibers which was positive for utrophin were prominent. In dystrophinopathy, the immunostaining of dystrophin and utrophin is useful, in combination with dystrophin gene analysis to make a definite diagnosis.

Progressive external ophthalmoplegia and myositis

We reported a senile male patient with progressive external ophthalmoplegia (PEO) and myositis. The ophthalmoplegia was severe, but other neuromuscular features were nearly normal. Muscle enzymes in serum were moderately elevated. Autoimmune, endocrinological or malignant diseases were not observed during the previous 4 years. Pathology of non-weak limb muscles biopsied twice was consistent with active inflammatory myopathy. The ragged-red or cytochrome c oxidase-negative fibers, which are a hallmark of mitochondrial myopathy with PEO, were not increased in comparison with age-matched control muscles. Analysis of mitochondrial DNA in muscle by the Southern blot method did not reveal any deletions. It was concluded that the inflammatory myopathy, myositis clinically localized at the ocular muscles, is an important and distinct disorder in PEO.

[A mother and her son with autosomal dominant bulbar spinal muscular atrophy]

We reported a 49-year-old mother and her 28-year-old son with autosomal dominantly inherited bulbar spinal muscular atrophy (AD-BSMA). They showed progressive bulbar paresis, muscle wasting and weakness dominant in the proximal groups of limb muscles, and finger tremor. Onset of illness was in adult life. In laboratory examinations, elevated creatine kinase in serum and neurogenic changes either in EMG or muscle biopsy were noted. The son had neither gynecomastia nor abnormal sexual hormone levels which were observed in the sex-linked recessive bulbar spinal muscular atrophy (SR-BSMA). Elongation due to the CAG repeats at the androgen receptor gene of the X chromosome in SR-BSMA was not detected. In conclusion, it is clear that AD-BSMA is different from SR-BSMA on the basis of clinical and genetical aspects.

[Quantitative skeletal muscle pathology of aging regarding ragged-red fibers and cytochrome c oxidase-negative fibers]

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.

[HTLV-I associated myelopathy (HAM) and sarcoid myopathy]

A 65-year-old house-wife developed dirty erythematous rash on her face in April, 1989. Almost simultaneously, she complained of muscle soreness and weakness on both lower extremities. Pathological findings of the skin biopsy at that time was consistent with those of sarcoidosis with moderate inflammatory cell infiltration. In December, 1989, when she was admitted to our hospital, her lower extremities were paretic with marked spasticity, and mild bladder dysfunction was noted. HTLV-I antibody titers in serum and cerebrospinal fluid were significantly elevated. Biopsied limb skeletal muscle revealed the findings of the sarcoid myopathy with small inflammatory cell infiltration in endomysium. HLA haplotypes showed A24, B7, BW61, CW7, CW8, DR1 and DR4 which show relatively common types of those in HAM. Corticosteroid treatments including the methylprednisolone pulse therapy healed the skin lesion, but did not improve her neurological signs. Paraplegia and urinary disturbance were progressive. It is concluded that the inflammatory sarcoid myopathy with HAM in this patient may be caused by a common abnormal immunological background.