Follow-up of nemaline myopathy in two patients with novel mutations in the skeletal muscle alpha-actin gene (ACTA1)

Nemaline myopathy has been associated with mutations in five different genes, which all encode protein components of the sarcomeric thin filaments. We report follow-up studies in two children with mutations not previously described in skeletal muscle alpha-actin (ACTA1). Case 1 was a male patient who after birth suffered from pronounced muscle weakness and hypotonia. Muscle biopsy showed small fibers with numerous rods. He failed to achieve any motor milestones. At the age of 17 he required 24 h ventilator support. He could not lift his arms against gravity, but he could use his hands to control his electric wheelchair. The muscle biopsy showed marked replacement of muscle tissue by fat and connective tissue. Only few fibers showed nemaline rods. He had a de novo, heterozygous mutation, G268D in ACTA1. Case 2 was a female patient with feeding difficulties and mild hypotonia in the neonatal period. Muscle biopsy showed hypoplastic muscle fibers and numerous rods. At 11 years of age she walked and moved unhindered and could run fairly well. She had a de novo, heterozygous mutation, K373E, in ACTA1. These two patients illustrate the marked variability in the clinical features of nemaline myopathy in spite of similar muscle pathology in early childhood. The severe muscle atrophy with replacement of fat and connective tissue in case 1 demonstrates the progressive nature of nemaline myopathy in some cases. The described two mutations add to the previously reported mutations in ACTA1 associated with nemaline myopathy.     

Multiple forms of acetylcholinesterase in nutritional and inherited muscular dystrophy of the chicken

Isozymes of acetylcholinesterase (AChE) are found in the cytoplasm of chick embryo muscle. They are maintained in muscles from birds with inherited muscular dystrophy and return with denervation but not tenotomy of normal muscle. The present study examined AChE activity in pectoral and lateral adductor muscles of birds with nutritional muscular dystrophy brought on by diets deficient in vitamin E, selenium, and sulfur amino acids, and containing excess arginine. Cytochemical and acrylamide gel electrophoretic studies showed that cytoplasmic AChE activity and embryo AChE forms appeared in pectoral muscle from vitamin E-deficient birds after 6 weeks of age. The cytoplasmic activity and embryo isozymes did not appear in muscles from birds grown with a vitamin E supplement. Cytoplasmic AChE activity was localized in focal regions of intact muscle fibers. The lateral adductor muscle of the leg was little affected. The results suggest that vitamin E deficiency interrupts neuromuscular interactions that suppress embryo AChE isozyme in “white” muscle of the chicken.     

Genuine myotubular myopathy

Two patients, a father and his 14-year-old son, were suffering from a facioperoneal syndrome, and muscle biopsy findings were consistent with a myotubular myopathy. The father exhibited central nuclei in most muscle fibers, but his son had typical changes exclusively in hypotrophic type I fibers. The cytochemical and ultrastructural analysis revealed a spectrum of pathological changes typical of myotubular myopathy. Energy-dispersive electron probe x-ray microanalysis was performed on 6-to 12-μm thick freeze-dried cryosections visualized in the scanning or scanning transmission mode of electron microscopy. We found a high intracellular sodium and chlorine concentration and a low potassium concentration in comparison with control muscles. These changes pointed in the direction similar to results from human fetal muscle. The changes in the intracellular elemental composition may indicate a membrane pump dysfunction, which might be caused by a partial arrest in muscle fiber maturation.     

Myopathological findings in thalassemia major

In thalassemia major (TM) one third of patients suffers from muscle wasting, weakness and cramps. Six patients with TM were studied. All had muscle wasting and proximal weakness; serum levels of vitamin E were low (0.6-7.0 micrograms/dl) while CPK, LDH and aldolase were normal. EMG revealed low-amplitude short-duration polyphasic potentials in 3 patients and normal activity in 3 others. Nerve conduction velocities were normal in 3 patients studied. On muscle biopsies, moderate variation in fiber size with fiber atrophy and preponderance of type 1 fibers were discovered. Our findings confirm the existence of nonspecific myopathic changes in TM. Chronic vitamin E deficiency should be considered in the pathogenesis of the myopathy in TM.     

Vitamin E deficiency associated with vision loss and bulbar weakness

We describe a 14-year-old boy who was severely debilitated by the neurological syndrome associated with vitamin E deficiency secondary to chronic cholestatic liver disease. In addition to the usual neurological deficits described with this deficiency, the patient had severe bulbar weakness and vision loss which we attribute to the degree and duration of his vitamin E deficiency. Vitamin A deficiency may have contributed to his visual disturbance. Early recognition of vitamin E deficiency is important, as the neurological and visual disorders which result are treatable.     

Familial idiopathic vitamin E deficiency associated with cerebellar atrophy

Sibling cases of familial vitamin E deficiency accompanied by ataxia, polyneuropathy and mental retardation were reported. Case 1 was a 37-year-old male who developed progressive gait disturbance, deformity of the feet and head tremor from childhood, after normal delivery and development of early childhood. On physical examination, he had cataract, high arched palate and pes cavus. Neurological examination revealed mental retardation (WAIS 68), scanning speech, muscular atrophy of the face and extremities with predominance in the lower limbs, absent Achilles tendon reflex, disturbance of superficial and deep sensation predominant in distal limbs, and marked gait ataxia. Ataxia was both cerebellar and sensory in nature. Laboratory data of the blood showed no significant abnormalities including blood glucose and vitamin B12 except a markedly low level of serum vitamin E. The brain CT scan revealed severe cerebellar atrophy and marked dilatation of the cisterna magna and the subarachnoid space around the cerebellum. Motor nerve conduction velocity in the leg was decreased. Biopsy specimen from the quadriceps muscle showed neurogenic atrophy. Sural nerve biopsy revealed decrease in large myelinated fibers with axonal degeneration and regeneration. Oral administration of alpha-tocopherol acetate, 600 mg per day, diminished ataxia significantly. Based on lysosomal enzyme activity in leukocytes, clinical and laboratory examination, lipidosis or spinocerebellar degeneration was excluded. Chronic lipid malabsorption or beta lipoprotein deficiency which can cause decrease in vitamin E absorption, was not recognized. On oral loading with 2 g of alpha-tocopherol acetate, the decrease rate of serum vitamin E was normal. Consequently the low vitamin E was considered to have resulted from selective impairment of vitamin E absorption.(ABSTRACT TRUNCATED AT 250 WORDS)     

A patient with vitamin E deficient, myopathy presenting with amyotrophy]

We report a 61-year-old man with vitamin E deficiency, presenting with, myopathy as an only clinical symptom. In 1997, at 59 years of age, he noted mild proxymal-muscle weakness and atrophy in the four extremities, nine years after he received a Billroth II partial gastrectomy for a gastric ulcer. His muscle weakness slowly exacerbated, and he was admitted to our hospital in 1999. On admission, neurological examination confirmed mild proximal-muscle weakness and atrophy in the four extremities. Intelligence, cranial nerves, coordination, sensation and tendon reflexes were all normal. Laboratory examination showed normochromic anemia (Hb 9.9 g/dl, Ht 30.9%, MCV 97.5 fl, MCHC 31.2 pg), hypoproteinemia (5.0 g/dl), and hypocholesterolemia (107 mg/dl). The levels of serum CK, lactate and pyruvate were normal. The serum vitamin E level was markedly reduced (0.17 mg/dl; normal 0.75-1.41). Cerebrospinal fluid was normal. Nerve conduction, sensory evoked potentials (SEP), electromyography (EMG), head CT and electroencephalography (EEG) were all normal. Muscle biopsy from the right deltoid muscle showed both mild myogenic and neurogenic changes. Remarkably, type 1 muscle fiber predominance and granular accumulation of autofluorescent lipofuscin granules in the muscle fibers were found. These pathological findings were compatible with those of vitamin E-deficient myopathy. Thus, he was diagnosed as having vitamin E-deficient myopathy, which was confirmed by apparent effective supplementation of vitamin E. Interestingly, our present case did not show any other neurological manifestations such as deep sensory disturbance, sensory ataxia or polyneuropathy. A long-term workload due to hard physical labor and smoking in our patient may have accelerated oxidative muscle damage, resulting in amyotrophy mainly due to vitamin E deficient myopathy.     

Unusual type of neural muscular atrophy with a possible X-chromosomal inheritance pattern

In a large family five affected males belonging to four different kinships exhibited a muscle wasting of varying degree and with a predominantly proximal distribution. The index case had a facio-scapulo-humeral and peroneal muscular atrophy, whereas one of his cousins suffered a more generalized involvement starting in infancy and similar to Werdnig-Hoffman disease. The other affected family members had only slight changes. The index case and his affected brother had a positive Babinski sign. In enzyme histochemical preparations, specimens from the index case showed small group atrophy of type 2 fibers along with pseudomyopathic changes (whorled and coiled fibers, splitting) of type 1 fibers. Similar findings were observed in his cousin. Ultrastructural investigation gave no further information. Since all patients were males and the offspring of unaffected sisters, an X-chromosomal mode of transmission is proposed for this illness.     

Necrotizing myopathy associated with hemolytic anemia in owl monkeys (Aotus trivirgatus)

In 40 owl monkeys with hemolytic anemia of unknown etiology, 37 had a myopathy characterized by focal or diffuse necrosis of sarcoplasm which was eosinophilic and floccular. Phagocytosis of necrotic fibers and regenerative changes were also observed. The severity of lesions roughly paralleled the severity of anemia and of centrilobular hepatic necrosis assumed to be caused by hypoxia. That the myopathy was not caused by anemia per se was suggested by the finding of mild myopathy in 10 of 24 monkeys known never to have been severely anemic. Although anemic owl monkeys are known not to be deficient in either vitamin E or selenium, parenteral vitamin E is partially protective against hemolysis in this species. The myopathy, which resembled that caused by vitamin E or selenium deficiency in other species, is probably the result of a metabolic abnormality involving vitamin E in an unknown way.     

The cardiomyopathy of Friedreich's ataxia morphological observations in 3 cases

In the light of the recent finding of deposits of calcium salts and iron in myocardial cells in one case of Friedreich's ataxia, we have made a detailed morphological study of 3 new cases of this cardiomyopathy. Calcium deposits were not found in the muscle fibers but lipofuscin granules and deposits of iron were observed in our 3 cases. In addition to the usual findings of interstitial fibrosis, hypertrophy and degeneration of myocardial fibers, foci of segmental active muscle necrosis were constantly present. There is a possibility that Friedreich's ataxia could be a neurocardiac degenerative disease with a membrane defect which could be related to defective metabolism of vitamin E or other micronutrients.     

Adult-onset spinocerebellar syndrome with idiopathic vitamin E deficiency

A 62-year-old man and his maternal uncle had a selective vitamin E deficiency without generalized fat malabsorption. A progressive neurological disorder comprising ataxia, areflexia, and loss of proprioception developed in their sixth and seventh decades. The vitamin E deficiency is thought to be due to abnormally accelerated utilization, excretion, or degradation of the vitamin. This adult-onset spinocerebellar syndrome is due to vitamin E deficiency not caused by malabsorption.     

Neuromuscular dysfunction and ultrastructural pathology in children with chronic cholestasis and vitamin E deficiency

The ultrastructural pathology of nerve and muscle and the neurological dysfunction in children with cholestatic liver disease and vitamin E deficiency have not been previously correlated. We studied two children with this syndrome. One child, 11 years of age, had severe hyporeflexia and decreased vibratory sense. Nerve conduction was delayed. The second child, 2 years of age, was neurologically normal. Both children showed ultrastructural evidence of damage to the sural nerve and accumulation of electron-dense deposits in the muscle fibers. Abnormalities of the nerves included disruption of the myelin sheath and separation and degeneration of the inner and outer components of the Schmidt-Lanterman incisure.     

Friedreich’s ataxia with isolated vitamin E deficiency: a neuropathological study of a Tunisian patient

The neuropathological findings in a Tunisian patient with Friedreich’s ataxia with vitamin E deficiency are reported. The main histological changes are: (1) spinal sensory system demyelination with neuronal atrophy, axonal spheroids and corpora amylacea; (2) neuronal lipofuscin accumulation in the third cortical layer of the cerebral cortex, thalamus, lateral geniculate body, twelfth and ambiguus nuclei, spinal horns and posterior root ganglia. Ultrastructurally, the lipopigments were of uniform granularity without lipid droplets. Received: 20 May 1996 / Revised, accepted: 6 October 1996     

维生素E对离心运动后大鼠骨骼肌线粒体内丙二醛、超氧化物歧化酶的影响

背景：许多实验表明自由基的增加与骨骼肌运动性损伤有关，而维生素E作为一种抗氧化剂，具有清除自由基的功效，可减轻运动中抗氧化酶所受的自由基损伤，减缓疲劳出现，进而提高运动能力。 目的：从细胞线粒体自由基代谢的角度，探讨维生素E对离心运动后大鼠骨骼肌细胞线粒体丙二醛、超氧化物歧化酶的影响，以进一步阐明维生素E抗骨骼肌运动性损伤的内在机制。 设计、时间及地点：随机分组，动物实验观察，于2007-05/10在沈阳体育学院国家体育总局重点实验室和中国医科大学重点实验室完成。 材料：雄性SD大鼠48只，体质量(304±12) g。随机分为对照组、运动组、生理盐水组、维生素E组，12只/组。 方法：维生素E组腹腔注射维生素 E胶丸，1.0~1.2 mg/kg，总量为4 mL/kg，初次注射时间为鼠正式实验前1 d，以后每8 h注射1次，共4次。生理盐水组以生理盐水为对照，注射方式、注射量及运动方式、处死时间同维生素E组。运动组只进行运动，不给予药物或生理盐水，对照组仅为常规饲养，无任何干预。采用一次力竭性下坡跑运动建造大鼠损伤模型，运动结束后，取大鼠右侧肱三头肌。 主要观察指标：采用微量测定试剂盒和6010紫外-可见分光光度计测定丙二醛含量及超氧化物歧化酶活力。 结果：肱三头肌细胞线粒体各组丙二醛、超氧化物歧化酶在离心运动后24 h均显著增加(P < 0.01)。与运动组比较，生理盐水组丙二醛、超氧化物歧化酶值均无显著性差异(P > 0.05)，维生素E组丙二醛显著降低(P < 0.01)，而超氧化物歧化酶显著增高(P < 0.01)。 结论：补充维生素E可降低骨骼肌细胞线粒体丙二醛的含量，增加细胞线粒体超氧化物歧化酶的活性，提高骨骼肌细胞的抗氧化能力，进而可减轻自由基对肌肉的损伤作用。维生素E对运动性骨骼肌损伤的预防作用主要是通过维生素E的抗氧化作用完成的。     

Heterogeneity of human skeletal muscle tropomyosin

Six polypeptides resolved by two-dimensional electrophoresis of homogenates from human skeletal muscle have been identified as tropomyosin by electrophoretic and immunochemical methods. The 6 proteins are consistently present in approximately the same abundance in normal biceps, deltoid, gastrocnemius, and quadriceps muscle. Analysis of samples from individuals with Becker's dystrophy, Duchenne dystrophy, limb girdle dystrophy, polymyositis, myopathy related to vitamin E deficiency, type II fiber deficiency, and from an infant with indistinct fiber type differentiation, however, showed quantitative variations in the tropomyosin pattern. Muscle with histochemically demonstrated type II fiber deficiency lacked two of the normal tropomyosin proteins and the type II myosin light chains. Muscles lacking type I myosin light chains were deficient in a different pair of tropomyosin proteins. The results suggest that normal human skeletal muscle contains one major type of tropomyosin protein (beta-tropomyosin) common to both fast and slow fibers, together with two other major proteins (alpha-tropomyosin and alpha'-tropomyosin), one of which is specific to fast fibers and the other to slow fibers. Preliminary data from the reaction of muscle homogenates with alkaline phosphatase indicate that 3 of the 6 tropomyosin polypeptides resolved by two-dimensional electrophoresis are phosphorylated forms of the alpha-, alpha'-, and beta-tropomyosins.     

Histoenzymatic profile of human muscle cultured in monolayer and innervated de novo by fetal rat spinal cord

We examined histoenzymatic characteristics of human muscle fibers grown in monolayer culture and innervated de novo in culture for 60-90 days by fetal rat spinal cord neurons. Serial cryostat cross sections were obtained using a freshly frozen sandwich of adult rat muscle and cultured human muscle. An advanced degree of morphologic and histoenzymatic maturation of cultured human muscle was reached after innervation. In contrast to aneurally cultured human muscle fibers, the innervated muscle fibers were smaller in diameter and had myonuclei preferentially located at the periphery of the fiber. The innervated fibers contained a well-developed intermyofibrillar network revealed by the NADH-TR and SDH reactions. Phosphorylase activity was strong to moderate in most muscle fibers. Although most of the innervated cultured muscle fibers were still not fully differentiated into two histochemical fiber types because they had strong ATPase activity after both alkaline and acid preincubation, a few of them had an ATPase profile similar to type 2 fibers in human adult muscle and had reciprocal staining with phosphorylase and NADH-TR reactions. This is the first evidence of differentiation into different histochemical fiber types of human muscle cultured in monolayer and innervated de novo by fetal rat spinal cord.     

Apolipoprotein E and apolipoprotein E messenger RNA in muscle of inclusion body myositis and myopathies

Sporadic inclusion body myositis and the hereditary inclusion body myopathies are severe, progressive muscle diseases, characterized pathologically by vacuolated muscle fibers containing paired helical filaments. We immunostained muscle biopsy specimens from sporadic inclusion body myositis, hereditary inclusion body myopathy, disease control, and normal patients with several antibodies against apolipoprotein E (ApoE). Approximately 80 to 90% of the vacuolated muscle fibers of sporadic inclusion body myositis contained well-defined, strongly immunoreactive ApoE inclusions, In hereditary inclusion body myopathy, only rare vacuolated fibers had immunoreactive inclusions, whereas most had diffuse cytoplasmic ApoE immunoreactivity. Ultrastructurally, ApoE immunoreactivity in sporadic myositis was localized mainly to the paired helical filaments. By contrast, in the hereditary form, ApoE immunoreactivity occurred on material in close proximity to the paired helical filaments, but never was on the paired helical filaments. In both muscle diseases, ApoE was also on the 6-to 10-nm filaments and amorphous material. In the sporadic form, ApoE-immunoreactive deposits colocalized with Congo red-positive deposits; however, in muscle fibers from patients with hereditary disease there was no congophilia. ApoE messenger RNA was not detectable in muscle fibers from patients with hereditary or sporadic disease but was expressed abundantly in muscle macrophages. In all control and inclusion body myositis or myopathy biopsy specimens, ApoE immunoreactivity was strong at the postsynaptic domain of neuromuscular junctions; nonjunctional regions of normal fibers were negative for ApoE. ApoE immunoreactivity occurred diffusely in regenerating muscle fibers, a subset of which had detectable ApoE messenger RNA.     

Unknown cause of familial neuromuscular disease with infiltration of cytotoxic/suppressor T cells

We report two brothers, aged 68 and 61 years respectively, who had an unclassified familial neuromuscular disease with infiltration of cytotoxic/suppressor T cells in muscle biopsies. The elder brother was in good health and active during child and adulthood until the age of 65 when muscle atrophy in the quadriceps muscle was noted. His muscle weakness and atrophy progressed relatively rapidly in the course of a few years. The muscle symptoms predominated in the under extremities at the initial stage, later to be generalized, sparing the facial muscles. The serum creatine kinase (CK) was 145 mu/ml (normal 5-80 mu/ml). EMG revealed myopathic changes. A biopsy taken from biceps muscle showed extensive inflammatory cellular infiltrations among fibers and in the perimysium. The infiltrated cells were identified to be cytotoxic/suppressor T cells. The younger brother first noticed diminished bulk in quadriceps muscle bilaterally at the age of 59. The muscle symptoms were similar to those seen in his brother. Serum CK was 520 mu/ml. EMG showed myopathic changes except for fibrillation potentials in the biceps. A biopsy taken from quadriceps muscle revealed the similar findings of his brother. The classification of these cases is a controversial subjects. We differentiated quadriceps myopathy, limb-girdle muscular dystrophy and myositis, which we couldn't classify. So at this point we reported these cases as unknown cause of familial neuromuscular disease.     

Reversible inflammatory and vacuolar myopathy with vitamin E deficiency in celiac disease

We report a patient with late-onset celiac disease and neurological manifestations including myopathy, polyneuropathy, and ataxia. Laboratory investigations showed anti-gliadin antibodies and severe vitamin E deficiency. Muscle biopsy revealed inflammatory infiltrates and rimmed vacuoles, similar to those found in inclusion-body myositis. A gluten-free diet and vitamin E supplementation reversed both the clinical neurological manifestations and the abnormalities in the muscle biopsy. Anti-gliadin antibodies were no longer present. This case illustrates the spectrum of neurological complications of celiac disease and documents the occurrence of reversible pathology resembling inclusion-body myopathy in the muscle.     

Vascular pathology in chronic progressive external ophthalmoplegia with ragged-red fibers]

Vascular involvement in biopsied muscle specimens from 11 patients with chronic progressive external ophthalmoplegia (CPEO) with ragged-red fibers (RRF) was studied. Almost none of 69 intramuscular arteries examined were strongly stained with succinate dehydrogenase (SDH) except one patient who had 2 SSV (strongly SDH-reactive blood vessels) in his muscle biopsy. Although RRF and focal cytochrome c oxidase (CCO) deficiency in muscle fibers were the common histochemical changes in muscle biopsy specimens from CPEO patients, all mitochondria in both endothelial and smooth muscle cells of the arteries had normal morphology except for the two SSV and all mitochondria in the blood vessels had normal CCO activity by electron cytochemistry. The findings obtained from the present study were quite different from those in mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS), and myoclonus epilepsy associated with ragged-red fibers (MERRF) in which the striking vascular involvement with SSV is the most common and major abnormality in muscle biopsy specimens. To study vascular involvement in mitochondrial encephalomyopathies is the one of very important clues to understand the pathophysiology of phenotypic expressions in mitochondrial encephalomyopathies.