Effects of L-carnitine, L-acetylcarnitine and gangliosides on the regeneration of the transected sciatic nerve in rats

Three pharmacological agents, L-carnitine, L-acetylcarnitine and gangliosides, were tested for their ability to enhance the regeneration of the rat sciatic nerve following transection and microsurgical repair. The drugs were administered intraperitoneally at the dose of 50 mg/kg/d for 28 and 56 d postoperatively. At the end of treatment, the motor function recovery of the peroneal component of the sciatic nerve was assessed and the regenerated nerves were analysed morphometrically on histological semi-thin sections. Also, the reinnervated extensor digitorum longus (EDL) muscles were studied histochemically using the adenosine-triphosphatase (ATP-ase) technique 56 d after surgery. Motor function assessment at 56 d after nerve repair revealed that L-acetylcarnitine-treated animals recovered a clinical grade significantly higher (p less than 0.05) than the control animals. Twenty-eight days after nerve repair, the number of myelinated fibres was significantly higher (p less than 0.05) in L-acetylcarnitine and ganglioside-treated animals than in control animals. However, 56 d after nerve repair the number of regenerated fibres in all the drug-treated groups was not significantly different from that of the control group. The EDL muscles of the drug-treated animals did not show significant differences from those of control animals with respect to fibre composition and fibre diameter although the L-acetylcarnitine-treated animals exhibited a significantly lower (p less than 0.05) degree of muscle atrophy than did the control animals. The results of the present work seem to indicate that L-acetylcarnitine and to a lesser extent gangliosides exert some favourable effect on the regeneration of the transected sciatic nerve in rats.(ABSTRACT TRUNCATED AT 250 WORDS

Centronuclear myopathy: histopathological aspects in ten patients with chilfhood onset Miopatia centronuclear: aspectos histopatológicos em dez pacientes com a forma clínica de início na infância

Centronuclear myopathy is a rare congenital myopathy. According to the period of onset of signs and symptoms and the degree of muscular involvement three clinical forms are distinguished: severe neonatal; childhood onset; and adult onset. We describe herein the muscle biopsy findings of ten patients with the childhood onset form of the disease including three cases with ultrastructural study. The biopsies disclosed increased nuclear centralization that varied from 25 to 90% of the fibers, type 1 predominance, great variability in fiber diameters, involvement in the internal fiber's architecture, and focal areas of myofilament disorganization. The main histopathologic differential diagnoses included type I fiber predominance, congenital fiber type disproportion, and myotonic dystrophy. The histologic abnormalities in centronuclear myopathy may be due to an arrest of maturation on the fetal myotubular stage. The cause of this arrest remains elusive.<br>A miopatia centronuclear (MCN) é uma forma rara de miopatia congênita. De acordo com a época do início dos sinais e sintomas e com o grau de envolvimento muscular são distinguidas três formas clínicas: forma neonatal severa; forma de início na infância; e de início na vida adulta. São apresentados neste estudo os achados histopatológicos de dez pacientes portadores da forma de início na infância da MCN. Os fragmentos musculares foram processados através de colorações de rotina e histoquímica, e em três casos foi realizado estudo ultraestrutural. Dentre os resultados obtidos, destacou-se o aumento da centralização nuclear na fibra muscular, que variou de 25 a 90%. Adicionalmente, foram observadas predominância de fibras do tipo I, variabilidade entre o diâmetro das fibras musculares, alterações da arquitetura interna das fibras musculares e presença de áreas focais de desorganização dos miofilamentos. Devido a estes aspectos, os principais diagnósticos diferenciais considerados foram as miopatias por predominância de fibras e por desproporção de fibras, e a distrofia miotônica. As anormalidades histológicas observadas na MCN podem ser devidas a uma parada no processo maturacional do músculo esquelético na fase miotubular fetal. A causa deste defeito ainda permanece sem explicação completa