Resazurin dye has been broadly used as indicator of cell viability in several types of assays for evaluation of the biocompatibility of medical and dental materials. Mitochondrial enzymes, as carriers of diaphorase activities, are probably responsible for the transference of electrons from NADPH + H+ to resazurin, which is reduced to resorufin. The level of reduction can be quantified by spectrophotometers since resazurin exhibits an absorption peak at 600 ηm and resorufin at 570 ηm wavelengths. However, the requirement of a spectrophotometer and specific filters for the quantification could be a barrier to many laboratories. Digital cameras containing red, green and blue filters, which allow the capture of red (600 to 700 ηm) and green (500 to 600 ηm) light wavelengths in ranges bordering on resazurin and resorufin absorption bands, could be used as an alternative method for the assessment of resazurin and resorufin concentrations. Thus, our aim was to develop a simple, cheap and precise method based on a digital CCD camera to measure the reduction of resazurin. We compared the capability of the CCD-based method to distinguish different concentrations of L929 and normal Human buccal fibroblast cell lines with that of a conventional microplate reader. The correlation was analyzed through the Pearson coefficient. The results showed a strong association between the measurements of the method developed here and those made with the microplate reader (r² = 0.996; p < 0.01) and with the cellular concentrations (r² = 0.965; p < 0.01). We concluded that the developed Colorimetric Quantification System based on CCD Images allowed rapid assessment of the cultured cell concentrations with simple equipment at a reduced cost.

Miastenia grave é doença neuromuscular caracterizada por excessiva fatigabilidade da junção muscular e envolve, particularmente, músculos inervados por nervos cranianos. Acredita-se que o defeito esteja localizado na junção neuromuscular. Os autores estudaram os achados histoquímicos e e morfométricos em 4 pacientes com miastenia grave mostrando que as fibras do tipo II eram significativamente menores que as fibras do tipo I.

Myasthenia gravis is a neuromuscular disease characterized by excessive fatigability of muscle function and particularly involves muscles innervated by the cranial nerves. It is believed that the defect is in the neuromuscular junction. The authors studied histochemical and morphometric findings in 4 patients with myasthenia gravis showing that the type II fibres were significantly smaller than the type I fibres.

Estudamos um paciente com quadro clínico rebelde, produzido por intoxicação pelo Parathion. Foi observado um fenômeno miotônico transitório, não descrito na literatura revisada. A constatação de cifras de AchE eritrocitária baixas e de colinesterase plasmática normais, indicou que era portador de déficit congênito de AchE, esclarecendo-se a evolução crônica do seu quadro. O fenômeno miotônico associado ao quadro clínico, eletrofisiológico, histológico e bioquímico fazem deste paciente um modelo clínico, de etiologia conhecida, da discutida síndrome de Isaacs.

A case of 38 year old man who worked with organochlorinated and Parathion during 5 years is reported. His follow-up was up to 2 years. The onset of the disease was characterized by cholinergic signs, headache, loss of weight, trembling, miokimias, fasciculations, ataxia, myotonic phenomena (in hands only) and motor sensitive peripheral polyneuropathy (affecting the lower limbs symmetrically). Low concentrations of blood cholinesterases confirmed the etiology. Myotonic phenomena disappeared spontaneuosly 6 months after the initial observation. One year later, the concentration of erytrocyte acetilcholinesterase was found to be low and plasma cholinesterase was normal, suggesting that the patient was carrier of a congenital deficiency of acetilcholinesterase. in literature relationship between myotonia and intoxication due to organophosphorus was not found. The whole clinical picture, cholinergic symptoms, transitory myotonic phenomena and spontaneous motor activity could be explained by an excess of acetilcholine. Eletromyography (EMG) in the first observation showed neuromuscular transmission blocking characterized by deficiency or absence of voluntary activity, unexcitability of fibular nerves, with fibrilations and positive peaks as described previously with Mipafox (another organophosphorus agent). During 2 years of observation numerous end-plates potentials of muscular fibres persisted in the EMG. A progressive increase in voluntary activity showed by unit motor potential of almost normal amplitude and very increased duration was observed. No potentials of reinnervation were noted. The results of EMG were explained as disturbances of neuromuscular transmission associated with moderate signs of denervation The Eaton-Lambert's test and the stimulation of a single unit motor potential confirmed disorder of neuromuscular synapses. The histochemistry of brachial biceps showed scattered atrophic and angulated type I and II fibres. Teased-fibres preparations showed nerve fibres with B, C, and G alterations as defined by Dyck et al. indicating axonal degeneration. These results were according to velocity of sensitive conduction. The conduction velocity of fibular nerves was strongly delayed during all the evolution indicating serious disorders of motor nerves myelin. We think that intoxication by organophosphorus should not be expressed as an identical alteration of both motor and sensitive nerves. The association of myotonic phenomena with such clinical, electrophysiological and histological picture is characteristic of the Isaac's syndrome model with known etiology.

São apresentados os resultados dos exames clínicos, eletrofisiológicos e do estudo do ponto motor, da imunofluorescência, da histoquímica e da ultrami-croscopia da biópsia muscular de um caso de miopatia miotubular. São discutidos estes resultados em relação aos achados de 56 casos desta moléstia consignados na literatura até 1978, sendo dada enfase à etiopatogenia.

A case of myotubular myopathy in a 10 years old girl is reported. Clinically, palpebral ptosis, ocular movements limitation, facial diplegia, posi-tivity of Gower's test, muscular hypotrophy distal, foot drop and deep absent reflexes were found. These signals were described by most of authors, besides symptoms referred, like partial urinary incontinency and frequent vomits. Reflexes H absents and teary in our patient were observed but were not described in the other cases of the literature. Routine laboratory tests were within normal limits; only aldolase was lightly elevated. In all muscles examinated it was noted a spontaneous electromyographic activity with +- of 2,64 ± 1,33 ms, 36,87 ± 30,87 µV and 88,13 ± 24,82 /s of frequency without characteristics of desenervation potentials of myoneural plates. The voluntary electromyographic activity was of myopathic pattern. A curve I/D made in the motor point of braquial biceps muscle was normal. The biopsy was made in the motor point of this muscle for histochemical, electron, immunofluorescence and vital stain microscopy. The biopsy showed 35% of fibras with central nuclei, predominance and hypotrophy of type I fibres, in some of them there were not myofibrils in the central zone, and poor differentiation between the fibre types in oxidative enzymes reactions. The electron microscopy confirmed the histochemical studies. The direct immunofluorescence was positive in some fibres. The vital stain showed beaded subterminal motor fibres. The clinical, electromyographic and principally histological findings suggest a innervation congenital disorder of muscle fibres.

É relatado um caso de doença de McArdle em paciente do sexo masculino, que apresentava cãimbras relacionadas a exercícios físicos e emissão de urina vermelha. A falta de elevação da taxa do lactato venoso após exercício físico em condições anaeróbicas, aliada à histoquímica do músculo, comprovaram o diagnóstico.

This disease was described by McArdle as an inherited autosomal recessive affection characterized by glicogen storage with normal chain in the skeletal muscles, due to absence of myophosphorylase activity. Under a clinical aspect, excessive fatigability, cramps and myoglobinuria appear following physical exercise. A case of this disease in a 36-year-old male patient is reported. Failure of elevation of venous blood lactate after physical effort under anaerobic conditions, as well as muscle histochemistry, made diagnosis confirmation possible. The authors comment on the differential diagnosis betwen McArdle's disease and the other causes of myoglobinuria, specially phosphofructokinase and carnitine-palmityl-transferase deficiency.

É relatado um caso de miopatia ocular tipo Kiloh-Nevin não-familiar com importantes alterações histoquímicas e ultraestruturais. O paciente apresentava fenômenos de natureza miastênica e dores musculares, achados pouco comuns. Do ponto de vista histopatológico foram assinaladas a abundante quantidade de "fibras rasgadas" ("ragged-red fibres") e a predominante atrofia nas fibras musculares tipo I. Também o estudo ultraestrutural mostrou a importância das alterações mitocondriais, notadamente a abundância de inclusões cristalóides na matriz mitocondrial. Os autores concluem tecendo considerações sobre a provável alteração à nível da transmissão neuromuscular, atribuindo a algum fator enzi-mático geneticamente determinado a etiopatogenia da miopatia.

A non-familiar case of Kiloh-Nevin ocular myopathy with important histochemical and ultrastructural abnormalities is reported. The patient, a 43 year-old male presented with 10 year long, progressive ocular ophtalmoplegia, myasthenic symptoms and severe muscular pain, an uncommon finding in this type of myopathy. The histochemical study showed muscular atrophy, mainly in type I fibres and a great amount of ragged-red fibres. Of particular interest, in this case, was the ultrastructural finding of severe mitochondrial abnormalities with a lot of inclussions in the cristae matrix; nevertheless these changes are not specific. The authors suggest a possible abnormality in the neuro-muscular transmission system and a genetically controlled enzimatic factor as responsible for the aethiology and pathogenesis of the Kiloh-Nevin ocular myopathy.