Distrofia muscular progresiva de Duchene y acetato de alfa-tocoferilo: condiciones clínico-terapéuticas / Progresive muscular dystrophy and alpha-tocoferilo acetate: clinic-therapeutic consideration

Se presenta un caso sobre Distrofia Muscular Progresiva Seudohipertrófica de Duchenne tipo infantil, en un niño de 8 años de edad, sexo masculino, con un año de evolución. Se menciona la evolución clínica favorable, en base a un seguimiento longitudinal del paciente con el empleo de vitamina E (Acetato de alfa-Tocoferilo)

Distrofia muscular progresiva de Duchene y acetato de alfa-tocoferilo: condiciones clínico-terapéuticas / Progresive muscular dystrophy and alpha-tocoferilo acetate: clinic-therapeutic consideration

Se presenta un caso sobre Distrofia Muscular Progresiva Seudohipertrófica de Duchenne tipo infantil, en un niño de 8 años de edad, sexo masculino, con un año de evolución. Se menciona la evolución clínica favorable, en base a un seguimiento longitudinal del paciente con el empleo de vitamina E (Acetato de alfa-Tocoferilo) (AU)

Partial deficiency of complexes I and IV of the mitochondrial respiratory chain in skeletal muscle of two patients with mitochondrial myopathy.

Respiratory chain enzymes were studied in isolated mitochondria of two patients with mitochondrial myopathy. Both patients had been suffering from chronic progressive external ophthalmoplegia and abnormal muscular fatigability since late childhood. One of the patients exhibited the complete triad of symptoms characteristic of Kearns-Sayre syndrome. Venous lactate levels at rest and during minimal exercise were increased in both patients. Histochemical examination of muscle revealed ragged red fibres and intermingled fibres negative for cytochrome c oxidase. Biochemical studies showed decreased activities of complex I and complex IV of the respiratory chain in both patients. Reduced minus oxidized spectra of mitochondrial cytochromes revealed a decreased content of cytochrome aa3 in only one patient, but a normal content in the other. A combined deficiency of complexes I and IV in muscle might either be due to a deficiency of a single subunit common to both complexes or to a coincidental deficiency of both complexes expressed either in the same or in different fibres.

Mitochondrial myopathies with necrotizing encephalopathy of the Leigh type.

Two patients with mitochondrial encephalomyopathy (MEP) serve to emphasize the variability of this group of diseases. Cerebral insults, mitochondrial cardiopathy, relapsing ileus, cerebral angioma, ataxia, and myoclonic seizures characterized the first case of an adult man with similar diseases in his family, interpreted as transitional form between mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) and myoclonus epilepsy associated with ragged red fibers (MERRF). The second patient, a floppy infant with cardiomyopathy and myoclonism, statomotoric and mental retardation showed combined defects in mitochondrial respiratory chain at NADH-CoQ reductase and cytochrome c oxidase and a deficiency of carnitine. In both patients neuropathologically criteria of Leigh's syndrome could be demonstrated in the cerebral cortex, in case 2 also clinically. The classificatory problems of the relationships between KSS, MELAS, MERRF, Leigh's as well as Alpers' syndromes are discussed.

Melas (Mitochondrial encephalopathy, lactic acidosis and stroke like episodes): relato de um caso / Melas (mitochondrial encephalopathy, lactic acidosis and stroke like episodes): report of a case

Relato de caso de menino de 12 anos de idade que apresentou diversas crises convulsivas, cefaléia e vômitos de difícil controle, concomitantes a sinais neurológicos focais. Esses episódios eram recorrentes e apresentavam regressäo, com permanência de discreto déficit. A investigaçäo revelou aumento do ácido láctico plasmático, lesöes semelhantes a infartos cerebrais e calcificaçöes nos gânglios da base. A biópsia muscular mostrou inúmeras fibras granulares (ragged-reds) e diminuiçäo da citocromo c oxidase no tecido muscular. É apresentada revisäo sobre as desordens mitocondriais com comprometimento do sistema nervoso central e músculos, enfatizando-se o diagnóstico e reconhecimento desta nova entidade, tendo em vista possível tratamento sintomático

Subpopulations of skeletal muscle mitochondria: response to ischemia.

The respiratory activity of distinct populations of subsarcolemmal (SS) and interfibrillar (IF) skeletal muscle mitochondria was studied in rat hindlimb muscle subjected to 30 min of global ischemia at 37 C. State 3 (ADP-dependent) and state 4 (ADP-independent) rates of respiration were determined polarographically using glutamate as the substrate, in order to calculate the respiratory control index (RCI). The RCI is the ratio of state 3 to state 4 respirations and is a sensitive indicator of mitochondrial coupling. An approximately 20 per cent decline in RCI was noted in the SS mitochondria following 30 min of warm ischemia. This decrease was a direct result of a significant decline in the state 3 respiratory rates. IF RCIs following the ischemic interval were not different from control. These data support the concept of separate populations of mitochondria within the skeletal muscle cell and demonstrate a specific injury pattern in the response to ischemia.

Effects of training on skeletal muscle in protein-deprived rats.

The effects of exercise on atrophy of muscle fibres and loss of mitochondria in the extensor digitorum longus (EDL) and soleus muscles were studied in protein deprived rats. They had smaller muscle fibres than aged-matched control rats, the difference being more evident in type 2 than type 1 fibres both in the fast EDL and slow soleus muscles. The loss of weight was more pronounced in the EDL muscle which is composed mainly of type 2 fibres than in the soleus muscle which is composed mainly of type 1 fibres. Protein deprived rats subjected to a programme of periodic running on a treadmill for 12 weeks showed less muscle atrophy than sedentary, protein deprived rats. This effect of exercise in diminishing the degree of atrophy was more pronounced in the type 2 than type 1 fibres. The protein deprived rats which had been sedentary showed a marked loss of subsarcolemmal mitochondria, which was not seen in protein deprived rats undergoing exercise.

Mitochondrial myopathy as a cause of ptosis and ophthalmoplegia in elderly females.

Of 27 patients with ptosis and ophthalmoplegia or both, and abnormal mitochondria in proximal limb muscles, 13 were elderly females, in whom symptoms began late in life. Clinical, electrophysiological, and morphological findings are presented, and possible etiological factors are discussed. The ocular mitochondriopathy in post-menopausal females seems to represent a separate, previously not described syndrome.