An electron microscopical study of the T-system in biopsied muscles from Fukuyama type congenital muscular dystrophy

The behavior of the tubular system in muscles from six patients with Fukuyama type congenital muscular dystrophy (FCMD) was examined by electron microscopy using a lanthanum nitrate stain for a comparison with that in Duchenne muscular dystrophy (DMD). In FCMD, many fibers showed morphological changes of the T-system as follows: aggregated tubular components forming honeycomb-like structures, focal dilatation of T-tubules with tangle formation, and numerous longitudinally projecting tubules, which were quite similar to those found in cases with DMD. The fibers with abnormal T-systems occasionally showed ultrastructural characteristics of regenerating fibers, including excessive ribosome particles, immaturely organized myofibrils, and an increased number of internal nuclei and satellite cells. The present results suggested that there was no qualitative difference in the behavior of the T-system between FCMD and DMD, and the morphological changes of the T-system in dystrophic muscles were not primary lesions initiating myonecrosis but reflected the behavior of sarcotubular formation in the process of muscle regeneration.

Diagnosis of partial deficiency of the pyruvate dehydrogenase complex in biopsied muscle

We have measured the total activity of pyruvate dehydrogenase (PDH) complex, by in vitro activation with a broad specificity protein phosphatase, and the basal activity, supposed to be present in vivo, in biopsied muscles from three patients with PDH complex deficiency and 11 patients with lactic acidemia. Results showed that the total PDH complex activity must be determined in biopsied muscles for the diagnosis, because the basal activities of two of three patients with PDH complex deficiency overlapped those of two patients with lactic acidemia whose total activities were within normal range.

Effects of thymic myoid cell culture supernatant on cells from lymphatic tissues

Conditioned media (MCM) of cloned thymic myoid cells (IT45R92, R613Ad, and R615B2) were used to investigate their possible involvement in thymic biological events. Those myoid cells produced in a culture medium biological activities capable of stimulating the growth of thymocytes, spleen cells, and bone marrow cells of mice and rats. Surface markers detected on spleen cells proliferating in MCM were characteristic of monocyte-macrophage lineages (C3R, Fc gamma R, asialo GM1) and T-cell lineages (Thy 1) but not B cells (sIgG). Chromatographic studies also suggested that the biological activities of MCM could be separated into two different molecular entities, such as a colony-stimulating activity and an interleukin 1-like activity which supported the growth of monocyte-macrophage lineages and T-cell lineages, respectively. These results indicate that thymic myoid cells produce cytokines important for the regulation of intrathymic interleukin cascade by which clonally differentiated thymic lymphocytes may be expanded into a sizable pool.

Congenital muscular dystrophy. A histochemical study with morphometric analysis on biopsied muscles

Muscle biopsies from 10 Japanese patients (9 females and 1 male) with congenital muscular dystrophy (CMD) were studied. Their clinical features varied remarkably in severity; one patient died at 6 years of age. Family history was negative in all but one patient who had an affected sibling. Muscle biopsy findings varied from mild myopathic to advanced dystrophic changes. Hypertrophic fibers associated with occasional fiber splitting were assumed to reflect a chronic dystrophic process. Histochemical examination revealed type 1 fiber predominance in 5 patients, and type 2 fiber predominance in one. Eight patients had a slight to moderate increase in the number of undifferentiated type 2C fibers suggesting a regenerating process after fiber necrosis. Type 2B fibers were fairly well preserved in 8 patients. The overall findings differed from those of the Fukuyama type congenital muscular dystrophy (FCMD) and Duchenne muscular dystrophy (DMD) in which more active fiber necrosis and regeneration are seen. We conclude that the present CMD patients suffered from a chronic dystrophic process similar to that in limb-girdle muscular dystrophy.

Localization of calcium-activated neutral protease (CANP) in the peripheral nerve

Localization of calcium-activated neutral protease (CANP) in the rat peripheral nerve was studied by an indirect immunofluorescent method, using rabbit antiserum against CANP extracted from chicken skeletal muscle. Its specificity to CANP, as well as its cross-reactivity with rat CANP, were confirmed by the Ouchterlony immunodiffusion procedure and immunoreplica method. CANP was demonstrated in the axon, but not in the myelin sheath or endoneurium. We could not conclude whether or not CANP in axons exists in association with neurofilaments.

Two siblings with multiple intracranial haemangiomatosis with calcification

Two siblings with multiple intracranial haemangiomatosis are reported, each having psychomotor retardation, epilepsy and gyriform type calcification in the occipital and frontal lobes. There were haemangiomas in one autopsy case with calcification in the deep layers of the cortex and subcortical white matter.

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.

Internodal microvillus-like Schwann cell fingers in myelinated fibres in mouse spinal roots

Collections of microvillus-like Schwann cell fingers identical to those described previously in the nodal gap substance were commonly found along the internodes of large myelinated fibres in the spinal roots of adult mice. They were covered by Schwann cell basal lamina and focally protruded from the outer cytoplasmic Schwann cell compartment. Unlike nodal Schwann cell fingers, these internodal fingers had no contact with the axolemma, but were directed toward the endoneurium. These were not recognized in the distal peripheral nerves. The frequent occurrence of internodal Schwann cell fingers in the spinal root fibres suggests that these structures may be involved in some electrophysiological regulatory mechanism in this particular region of the nervous system.

Fatal infantile mitochondrial myopathy and renal dysfunction caused by cytochrome c oxidase deficiency: immunological studies in a new patient

A 3-month-old female infant had profound generalized weakness, de Toni-Fanconi-Debre syndrome, and lactic acidosis. She required assisted ventilation and died at the age of 8 months. Muscle biopsy showed accumulation of mitochondria, glycogen, and lipid droplets. Histochemical reaction and immunocytochemical stain for cytochrome c oxidase showed very weak results, but both reactions were normal in intrafusal fibers of the muscle spindle. In crude extracts of the patient's muscle, cytochrome c oxidase activity was undetectable and enzyme-linked immunosorbent assay showed decreased reaction at all dilutions of antiserum. These data indicate that the amount of immunoreactive enzyme protein is markedly decreased in muscle of patients with fatal infantile cytochrome c oxidase deficiency and renal dysfunction.

Successful carnitine treatment in two siblings having lipid storage myopathy with hypertrophic cardiomyopathy

Two Japanese siblings had lipid storage myopathy with hypertrophic cardiomyopathy (HCM). They had slowly progressive muscle weakness and ventricular hypertrophy of the heart evidenced by electrocardiography and echocardiography. Their developmental milestones were normal until three years of age when mild weakness in the lower limbs became evident. Laboratory examination showed transient high creatine kinase levels (CK) and hyperammonemia. Histochemical investigation on the muscles revealed abnormal accumulation of sudanophilic lipid droplets predominantly in type 1 fibers, type 2 A fiber atrophy and type 2 B fiber deficiency. In case 1, excessive lipid droplets were also observed in the biopsied cardiac muscle. Carnitine was decreased in the skeletal muscles and the serum. Treatment with DL-carnitine to both cases resulted in marked clinical improvement and decreased lipid droplets in the muscles.

Skeletal muscle involvement in Escobar syndrome

In addition to the clinical characteristics of Escobar syndrome, including an anomalous facial expression, multiple joint contractures, multiple pterygia and a short stature, two female siblings developed proximal dominant muscle weakness from birth and slowly progressive scoliosis. Biopsied specimens obtained from the paravertebral and gluteus maximums muscles at the time of spinal surgery showed variation in fiber size, increased numbers of fibers with central nuclei, interstitial fibrosis and disorganized intermyofibrillar networks with occasional core/targetoid formations. The most outstanding histochemical abnormality in both cases was an abnormal fiber type distribution (type 2 fiber deficiency) which might be the result of an abnormal or deficient neural supply to the developing muscles. The defective neural influence on the muscle is assumed to produce the above-mentioned muscle changes, inducing multiple joint contractures and scoliosis.

Congenital muscular dystrophy with severe infantile scoliosis

A girl with congenital muscular dystrophy with severe scoliosis from birth was presented. No positive family history was obtainable. She developed muscle hypotonia and weakness, and feeding difficulty during the neonatal period. Her developmental milestones were delayed; she learned to walk at the age of 2 years when she walked with a "waddling gait" and stood up with Gowers' maneuver. On physical examination at 2 years old, she had mild proximal dominant muscle weakness and atrophy, and severe scoliosis with a Cobb's angle of 74 degrees but no joint contractures in the extremities. Creatine kinase was slightly elevated. Biopsied muscle showed myopathic changes, including variation in fiber size, moderate fibrous tissue proliferation, some necrotic and regenerating fibers and type 1 fiber predominance, consistent with those seen in chronic progressive muscular dystrophy.

Autosomal recessive distal muscular dystrophy: a comparative study with distal myopathy with rimmed vacuole formation

To clarify the clinical and morphological characteristics of distal muscular dystrophy, clinical and pathological material from 4 affected persons was compared with similar studies in 4 patients with distal myopathy with rimmed vacuole formation. Although these two forms of autosomal recessive distal myopathy with onset in young adulthood were highly similar in their clinical symptoms, histochemical and electron microscopic findings of muscles subjected to biopsy were quite different. The muscle abnormalities in distal muscular dystrophy were almost the same as those in Duchenne muscular dystrophy, showing massive fiber necrosis followed by active fiber regeneration. In contrast, distal myopathy with rimmed vacuole formation showed a progressive muscle fiber atrophy and loss, rimmed vacuoles in the sarcoplasm, and no apparent fiber necrosis or regeneration.

A genetic variant of Emery-Dreifuss disease. Muscular dystrophy with humeropelvic distribution, early joint contracture, and permanent atrial paralysis

A 38-year-old woman, a product of consanguineous parents, had been observed to have limited neck flexion and elbow joints contracture since early childhood. In addition, she experienced humeropelvic muscular weakness and atrophy, so that she was unable to walk by age 27. At 34 years of age, she required a permanent pacemaker to treat complete atrioventricular block with ventricular bradycardia. A myocardial biopsy confirmed cardiomyopathy. The clinical features of the present case are similar to those of the Emery-Dreifuss syndrome; however, this case may be inherited through an autosomal recessive trait.

Clonal heterogeneity of thymic muscle-cell precursors

Three myoid-cell clones were established from the thymuses of two Wistar rats; one thymus yielded two clones, R615A and R615B2, and the other yielded one clone, R613Ad. The three clones were divided into two subtypes. Both subtypes were able to form myofibrils, expressed AChR on their cell-surface membrane, and contained myofibrillar ATPase characteristic of undifferentiated type-2C fibers, but they differed from each other in morphology, expression of Thy 1 antigen, spontaneous contractility, and qualitative accumulation of AChR. Immunolocalization studies using antisera against the respective cell subtypes also indicated regional differences in their cellular origin. These results show that the thymus contains heterogenous myoid-cell precursors.

Demonstration of acid alpha-glucosidase in different types of Pompe disease by use of an immunochemical method

The nature of mutant acid alpha-glucosidase (AAG) in muscle was studied in 6 patients with Pompe disease, consisting of 2 each of the infantile, childhood and adult types. Anti-human liver AAG rabbit antibody prepared in the present study was confirmed to be monospecific by immunodiffusion, immunotitration and immunohistochemical methods. It was found by the immunodiffusion and enzyme immunoassay methods using this antibody that the mutation produced a normal amount of enzyme protein but the latter was an inactive form, suggesting structural gene mutation in 5 of the 6 cases. In the remaining childhood type case there was no detectable amount of enzyme protein, suggesting that the mutation causes a reduction in the amount of the enzyme protein or synthesis of unstable enzyme protein. Similarly, the enzyme activity of AAG was markedly reduced in all patients, but that of neutral alpha-glucosidase was the least reduced in the adult type, medium in the childhood type, and the most reduced in the infantile type.

Muscular abnormalities in experimental hypothyroidism of rats with special reference to the mounding phenomenon

The mounding phenomenon was examined in vitro on the excised extensor digitorum longus or soleus muscle of hypothyroid rats. The mounding phenomenon was more prominent and lasted longer in hypothyroid muscles than in controls. In single skinned muscle fibers of both type 1 and type 2 from hypothyroid animals, the maximum tension produced by Ca ion was reduced and activity of Ca uptake by the sarcoplasmic reticulum was also decreased, judging from the response to caffeine. Decreased Ca uptake might retard the relaxation of contracture, thereby rendering the mounding more prominent. Morphological studies of both extensor digitorum longus and soleus muscles showed an increase of type 1 muscle fiber population as well as mild changes in arrangement of the internal membrane system. However, there was no muscle necrosis or other derangements. These results supported the idea that functional abnormality of the sarcoplasmic reticulum could be the basis of the exaggeration of the mounding phenomenon in hypothyroidism.

6-Aminonicotinamide-induced hydrocephalus in suckling mice

Following a single intraperitoneal injection of 6-aminonicotinamide (6-AN, 50 mg/kg of body weight) into newborn mice of the Institute of Cancer Research strain, hydrocephalus consistently developed nine days after injection, with rapid progression. All of these mice died before reaching adulthood. The most striking early histologic change in these mice was cytoplasmic vacuolation of ependymal cells, which was observed as early as 24 hours after injection. Vacuolation of subependymal astrocytes appeared during the next few days. After day seven, the aqueduct was obliterated by swollen vacuolated ependymal cells and subependymal astrocytes. The aqueduct remained obliterated even after the vacuolation of the ependymal cells subsided after day nine, when vacuolation of subependymal astrocytes was still pronounced. These morphological observations reveal that, in newborn mice, the ependymal cells are the most sensitive to the toxic action of 6-AN and suggest that the pathogenesis of 6-AN-induced hydrocephalus is likely to be due to the combination of ependymal cell damage and compression of the lumen by the edematous periaqueductal gray matter. This is a highly reproducible animal model of drug-induced hydrocephalus.

Behavior of sarcotubular system formation in experimentally induced regeneration of muscle fibers

To examine the behavior of transverse (T)-tubule formation in experimentally-induced regenerating fibers, a local anesthetic, bupivacaine hydrochloride, was injected directly into the rat soleus muscle to cause myonecrosis. The regenerating fibers following necrosis were then examined by electron microscopy using lanthanum nitrate which clearly demonstrated the sarcotubular system. In the early stage of regeneration within 7 days after muscle necrosis, the T-tubules seemed to be composed of markedly proliferated subsarcolemmal caveolae with occasional honeycomb structure formation. Around 10 days, the T-tubules in regenerating fibers were tortuously and irregularly arranged with focal dilatation in diameter, and extended longitudinally along the axis of well organized myofibrils. As the regenerating fibers matured, the sarcotubular system, irregular in course and in shape, gradually became organized into a regular transverse position against the myofibrils, along with a marked decrease in longitudinally arranged tubular components. These morphological findings of the early T-tubule formation seen in the present study were similar to those found in early myogenesis, and in biopsied muscles from cases of polymyositis and progressive muscular dystrophy.

Regenerative capability of skeletal muscle in chicken muscular dystrophy

To examine the morphological sequence of regenerating fibers after myonecrosis in dystrophic muscles, 0.5 ml of 0.5% bupivacaine hydrochloride (BPVC) (Marcaine) solution, a local anesthetic with a cytotoxic effect on the muscle fibers, was injected directly into the dystrophic (line 413) and nondystrophic (line 412) posterior latissimus dorsi (PLD) muscles of young and adult chickens. Although the dystrophic muscles after BPVC injection showed a rapid recovery with a similar tempo to that of nondystrophic ones, they showed different morphological behavior in the early phase of regeneration, including marked variability in the size of fibers and in the intracytoplasmic enzyme activities of nicotinamide adenine dinucleotide, reduced-tetrazolium reductase (NADH-TR), acetylcholinesterase (AChE), and nonspecific esterase (NSE).

Two-step mechanism of myofibrillar protein degradation in acute plasmocid-induced muscle necrosis

Acute muscle necrosis was induced in rats by intramuscular injection of plasmocid, a known myotoxic agent. A single injection of 5 mg/ml plasmocid produced massive fiber necrosis with extensive phagocytosis. Plasmocid administration led to a preferential decrease of alpha-actinin with preservation of other structural proteins within 3 h after injection, and large increases (2-7-fold) in the activities of acid hydrolases, cathepsins B and L, cathepsin D and alpha-galactosidase within 48 h after injection. The plasmocid-induced stimulation of alpha-actinin loss seen at 3 h, when no increases of acid hydrolases occurred, could be inhibited by a cysteine protease inhibitor, Ep-475 (E-64-c), and EGTA. On the other hand, increased lysosomal enzyme activity seemed to have a close correlation with the appearance of invading mononuclear cells, probably macrophages, and not muscle lysosomes. These observations suggest that a two step mechanism of protein degradation (nonlysosomal and lysosomal processes) possibly occurs in plasmocid-induced muscle degradation and macrophages can serve as a main endogenous reservoir of proteases in pathological states.

Idiopathic hyperCKemia

In three adult men, serum creatine kinase activity was constantly raised for at least 4 years. They had been normal in other neuromuscular functions and did not have any established disease. Quantitative morphologic and pharmacologic studies were performed on biopsied muscle. The biceps brachii of patient 1 contained 0.3% necrotic fibers. In patient 2, only slight variation of muscle fiber diameter was noted. Muscle of patient 3 contained a few small angular fibers, and 11% of fibers exhibited internal nuclei. Sensitivity to caffeine in vitro was increased in patients 2 and 3, as seen in survivors of malignant hyperthermia; patients in hyperCKemia may be susceptible to malignant hyperthermia.

Childhood acid maltase deficiency. A clinical, biochemical, and morphologic study of three patients

Three children, including two siblings and a patient with sporadic glycogenosis type II (childhood form of acid maltase deficiency [AMD] ), were studied clinically, biochemically, and morphologically. In addition to a delay in developmental milestones and mild generalized muscle weakness, nasal vocalization and an electromyographic finding of abnormal insertion voltage, followed by pseudomyotonic discharge, were assumed to be characteristic diagnostic findings for the childhood form of AMD. Since the neutral maltase activity was highest in the muscle biopsy specimen from the patient with the least severe weakness, the enzyme may play a role in reducing muscle involvement. Selective type 2A fiber atrophy and type 2B fiber deficiency in the affected muscles were the common histochemical findings in this particular form of AMD.

Muscle fiber type differentiation and satellite cell populations in normally grown and neonatally denervated muscles in the rat

To examine the neural influence upon fiber type differentiation in developing muscles, newborn rats were subjected to sciatic nerve dissection, and the denervated extensor digitorum longus (EDL) (white) and soleus (red) muscles were examined in chronologic sequence by means of histochemistry and electron microscopy. The skeletal muscles in the newborn rats were undifferentiated (type 2C fibers seen on ATPase staining) and contained numerous myotubes. In the controls, the type 2C fibers started to differentiate at around 5 days and had almost completed type differentiation by 30 days in EDL and by 90 days in soleus muscles. On the other hand, none of the fibers in the neonatally denervated muscles developed into well differentiated type 1 and 2 A fibers, but both the EDL and soleus showed long-lasting type 2C and 2B populations. The satellite cells in the denervated EDL and soleus muscles decreased in number at the same rate as in the control muscles with maturation. The absence of a neural supply in the developing muscles induced a delay in muscle fiber type differentiation but did not influence the satellite cell populations in either EDL or soleus muscles.

Fatal lipid storage disorder

A 12-week-old female infant died from acute encephalopathy mimicking Reye syndrome. Because of positive serum hepatitis B surface antigen (HBs Ag) and perivascular inflammatory cell infiltration in the liver, she was diagnosed as having acute hepatitis. The most striking finding in the present case was extremely excessive lipid accumulation in the striated muscles including biceps brachii, tongue and cardiac muscles. The levels of serum, liver and muscle carnitine were within normal limits, though liver carnitine palmityl transferase (CPT) was markedly decreased in activity. Although the primary metabolic defect has yet to be elucidated, it is assumed that the fulminant hepatic failure induced lipid accumulation in the skeletal muscle by a certain abnormal lipid metabolism.

Congenital myopathy without specific features (minimal change myopathy)

Three patients including a father and his daughter as well as a sporadic case who had a history of delayed developmental milestones showed symptoms of generalized muscle weakness predominantly in the neck flexors, high-arched palate, slender stature, myopathic face and nasal tone vocalisation. Histological and histochemical examinations on the biopsied muscles demonstrated minimal nonspecific changes; mild variation in fiber size, slight abnormality in fiber type distribution and an increased number of undifferentiated type 2C fibers. The abnormal muscle pathology was assumed to have resulted from delayed muscle fiber growth and differentiation due to a probable defective neural influence upon the developing muscles.

Effect of cycloheximide administration on bupivacaine-induced acute muscle degradation

We have examined the effect of cycloheximide on bupivacaine-induced, macrophage-mediated muscle degeneration in rats and obtained the following results. Direct intramuscular injection of bupivacaine into soleus muscle caused uniform muscle degeneration (Ishiura, S. et al. (1983) J. Biochem. 94, 311-314). The degeneration was most prominent 48 h after injection, with many infiltrating macrophages. Intraperitoneal administration of cycloheximide prevented the bupivacaine-induced macrophage invasion and decrease of structural proteins 48 h after injection. Cycloheximide inhibited the increase in lysosomal enzymes in bupivacaine-treated muscle. The peritoneal macrophages increased in number immediately after bupivacaine injection, while cycloheximide inhibited their accumulation. These results indicated that cycloheximide inhibited muscle degradation by preventing macrophage proliferation.

Malignant hyperthermia and related neuromuscular diseases: caffeine contracture of the skinned muscle fibers

Using the skinned fiber preparation, the response to caffeine was studied on the skeletal muscle of malignant hyperthermia or other neuromuscular diseases. The sensitivity to caffeine was increased in the muscle of malignant hyperthermia. The sensitivity also was increased in Duchenne muscular dystrophy or asymptomatic patients with raised serum creatine kinase activity. Judging from the interaction between caffeine and the contractile system, the abnormal response originated from the sarcoplasmic reticulum in malignant hyperthermia. In Duchenne muscular dystrophy, the contractile system also might be involved in the increased sensitivity. Since the disease spectrum presenting abnormal responses is broad, it is suggested that muscle fibers become sensitive to caffeine when they are degenerating or regenerating.

Immunocytochemical localization of cathepsin B in degenerating rat skeletal muscle induced by a local anesthetic, bupivacaine

Experimental acute degenerative changes in skeletal muscle accompanied by a drastic increase in cathepsins B&L were induced in rats by intramuscular injection of a local anesthetic, bupivacaine. Cathepsins B&L have been implicated in the rapid disappearance of muscle fibers. Degenerating muscle showed a spotty fluorescence when stained with antibodies against cathepsin B, indicating that the increased cathepsin B did not originate from the muscle itself, but from invading phagocytes. We report here results showing that cathepsin B of nonmuscle cell origin is involved in the breakdown of myofibrillar proteins in acute bupivacaine-induced muscle degeneration.

Fetal muscle characteristics in nemaline myopathy

In addition to the intracytoplasmic rods in approximately 1/4 muscle fibers, there were a large number of fibers with fetal muscle characteristics in a female infant who had severe muscle weakness and hypotonia, and failure to thrive since birth. A histochemical examination disclosed abnormal distribution in muscle fiber types including remarkable type 1 fiber predominance and increased number of type 2 C fibers (11.4%). Scattered throughout were fibers consisting of multiple myocytes enclosed in a single basement membrane, and small-calibered fibers containing abundant intermediate (skeleton) filaments and dispersed microtubules. Both were histologically identical to premature fibers found in the fetal muscle. The existence of an increased number of satellite cells as compared with age-matched controls was also suggestive of delayed or arrested muscle fiber maturation. A certain impaired neural influence upon the developing muscle is probably responsible for producing abnormal fiber type distribution and immature small-calibered fibers which account for small muscle bulk and muscle weakness in nemaline myopathy.

Pathophysiology of muscle fiber necrosis induced by bupivacaine hydrochloride (Marcaine)

A single direct injection of a local anesthetic, 0.5% bupivacaine hydrochloride (BPVC) (Marcaine), into rat soleus and extensor digitorum longus (EDL) muscles produced massive fiber necrosis with extensive phagocytosis followed by rapid regeneration, predominantly in the soleus. Since the sarcoplasmic reticulum (SR) was functionally disturbed by BPVC administration as confirmed by an in vitro study, the sarcolemmal lysis seen in the early phase of degeneration was not assumed to simply result from direct damage to the plasma membrane caused by BPVC. The extracellular fluid containing a high concentration of calcium (Ca) ions then permeated into the sarcoplasm through the defective membrane resulting in hyper-contracted myofibrils. Selective damage to the Z-line, an early sign of muscle degeneration, was shown by electron microscopy and SDS gel electrophoresis (preferential loss of alpha-actinin). Administration of leupeptin, a thiol protease inhibitor, proved to be ineffective in inhibiting the necrotic process, because the BPVC induced muscle fiber breakdown was probably too acute and fulminant to demonstrate the inhibitory effect upon the degenerative process. Well preserved satellite cells, peripheral nerves, and acetylcholinesterase activity, and the absence of fibrous tissue proliferation in this system may be responsible for the extremely rapid regeneration with complete muscle fiber type differentiation. Since the sequence of fiber breakdown induced by BPVC administration was similar to that of progressive muscular dystrophy, this chemical will be one of the most useful tools for studying the pathophysiology of fiber necrosis and regeneration in diseased muscle.

Vacuolar myopathy with type 2 A fiber atrophy and type 2 B fiber deficiency. A case of childhood form acid alpha-1,4-glucosidase deficiency

This report describes a female patient with childhood form of acid maltase deficiency who survived till fifteen years old. Although acid alpha-1,4-glucosidase was deficient in the liver, kidney, skeletal and cardiac muscles, neutral alpha-1,4-glucosidase was present in normal concentrations in those organs. On light microscopic examination, numerous intracytoplasmic vacuoles containing acid phosphatase positive granules and PAS positive materials were present in both type 1 and 2 A fibers, predominantly in the latter. The striking finding in the present case was a selective type 2 fiber atrophy with type 2 B fiber deficiency believed to result from type 2 motor neuron dysfunction in the spinal cord. Electron microscopic study revealed extensive glycogen particle accumulation, autophagic vacuoles and myelin figures in the muscle fibers.

Involvement of the Onuf nucleus in Werdnig-Hoffmann disease

Contrary to contention that Onuf nucleus is spared in Werdnig-Hoffmann disease (WHD) as it is in ALS, we found central chromatolysis in the Onuf neurons of the sacral cord from all five WHD patients. They were less depopulated but the central chromatolysis appeared more frequently than in anterior motor neurons. In contrast, the sacral autonomic neurons were not affected in any of the five cases. This argues against the view that the Onuf nucleus is autonomic and is spared with other autonomic neurons.

Adult form acid maltase deficiency -- a case report

The case of a 26 year old man with acute respiratory difficulty was reported. Morphological and biochemical analysis of biopsied gastrocnemius muscle indicated a diagnosis of adult form acid maltase deficiency. Clinically, the most interesting point of our case was the presence of a thickening of the posterior papillary muscles and chordae without any functional disturbance, which was detected by echocardiogram. Another interesting point of our case was the existence of a sibling who died of progressive muscular dystrophy at the age of 31 years. This may raise the possibility that we are dealing with a familial type of adult form acid maltase deficiency.

Myosin light chain components in single muscle fibers of Duchenne muscular dystrophy

Single muscle fibers were prepared from biopsy specimens of Duchenne muscular dystrophy (DMD), normal, and neuromuscular disease controls. Single muscle cells were classified as type 1, type 2, or intermediate by the skinned fiber method. The intermediate fiber was most abundant in DMD, comprising 29% of fibers examined. The fiber type of single muscle fibers was contrasted to the composition of myosin light chain (MLC) components, which was analyzed by micro two-dimensional gel electrophoresis. In DMD, each of the components exhibited the same electrophoretic mobility as those in the controls. Type 1 fibers of DMD were more diverse in the composition of MLC than those of controls; 55% of type 1 fibers of DMD contained distinct fast-type MLC 3. Some intermediate fibers contained all five MLC components, but in others the composition was not different from usual type 1 or type 2 fibers. The diversity of MLC composition in DMD muscle cells might reflect the abundance of young muscle fibers in the tissue due to active muscle regeneration and/or retardation of maturation.

Muscle histochemistry in congenital muscular dystrophy with central nervous system involvement

Muscles from 13 patients with clinical characteristics of congenital muscular dystrophy and central nervous system involvement (Fukuyama type) (FCMD) were examined using morphometric and fiber type analysis. The muscles from patients aged 5 months to 3 years demonstrated small-calibered fibers with increased variation in fiber size, connective tissue proliferation, and scattered necrotic and regenerating fibers. Groups of atrophic fibers were absent. Both type 1 and type 2 fibers were affected, though type 1 fibers predominated and type 2B fibers decreased as the disease progressed. The muscle changes were apparently progressive, affecting not only the limbs but also the intercostal, diaphragm, and cardiac muscles. Although there was no qualitative difference in the muscle histochemistry between FCMD and Duchenne muscular dystrophy (DMD), there was a greater proportion of type 2C fibers and fibrosis was present at the early infantile stage of FCMD.

Basilar artery occlusion in a case of Duchenne muscular dystrophy

This is a report of a case of Duchenne muscular dystrophy (DMD), with multiple infarcts in the territories of the basilar artery. He developed abrupt vomiting and transient left hemiparesis at the age of 4 years. The episodes were seen 3 times between 4-year-1-month to 5-year-1-month old. Transaxial computerized tomography (CT) revealed multiple, well-defined but irregularly marginated areas of low density centered in the mid- and upper pons, right cerebral peduncle and thalamus. A right vertebral angiogram illustrated the narrowed basilar artery. The rectus femoris muscle was biopsied at the age of 4-year-1-month which showed marked variation in fiber size, myonecrosis with phagocytosis, central nuclei, and adipose and connective tissue proliferation, which were consistent with those seen in DMD. It remains unknown whether the basilar artery occlusion was an incidental event in this particular case or closely related to the disease process of DMD.

Therapeutic trial with protease inhibitor (leupeptin) in chicken muscular dystrophy. A histologic and histochemical study

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.