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Biomedical subjects

S A Barron

Publications and source records attributed to S A Barron.

33 records · Page 2Linked to original sources
PubMed1981

Polymyositis beginning as a focal process.

Six patients with polymyositis initially complained of a single, localized, painful mass involving an extremity. The mass enlarged during the course of a two- to six-week period. Biopsy of the lesion revealed myopathic changes with inflammation, and the diagnosis of benign inflammatory pseudotumor was considered. The mass regressed, but during the next three to six months, a rapidly progressive generalized myopathy developed that caused weakness of the trunk and extremities in association with malaise and weight loss. Subsequent muscle biopsy specimens obtained from a site remote from the original mass were again characterized by lymphocytic infiltration, fiber necrosis, and regenerative activity. Our experience indicates that polymyositis may begin as a focal process that mimics a localized inflammatory pseudoneoplastic reaction. An essential clue to the diagnosis of polymyositis at this early stage is the elevation of ESR and serum creatine phosphokinase levels that does not occur in pseudotumor. The muscle biopsy further serves to distinguish polymyositis from pseudotumor.

Adult↗
PubMed1981

An eye movement disorder in amyotrophic lateral sclerosis.

Defective pursuit eye movements were recorded by electrooculography (EOG) in 11 of 18 patients (61%) with amyotrophic lateral sclerosis. Pursuit defects consisted of a breakdown of smooth tracking into saccadic motions that were grossly in excess (frequencies and amplitudes) of saccadic interruptions of pursuit in normal subjects. In nine patients, defective pursuits cogwheeling) were obvious by visual inspection as well as by EOG; in two, this abnormality was seen only by EOG. In eight patients, the pursuit defect was the only abnormality of oculomotor function; in three, there were also saccadic defects (optokinetic nystagmus or conjugate gaze) discerned by EOG. Autopsy revealed neuronal degeneration in substantia nigra and demyelination in integral capsule in one patient with the pursuit defect but not in another patient without the defect. The pursuit defect may be a sign of extrapyramidal or supratentorial pyramidal involvement in ALS.

Adult↗
PubMed1980

Denervating changes in focal myositis, a benign inflammatory pseudotumor.

Focal myositis is a benign pseudotumor of skeletal muscle, the cause of which is obscure. It usually appears as a steadily enlarging mass within the muscle of an extremity. The pathologic features are those of an inflammatory myopathy in which lymphocytic infiltrates, muscle cell necrosis, and regeneration are seen. Four cases of focal myositis were studied using enzyme histochemistry and electron microscopy. The changes of denervation atrophy, reinnervation, and fiber hypertrophy were found. Intramuscular nerve damage manifested by axonal swelling, demyelination, and endoneurial fibrosis was evident. The findings suggest that a denervating process plays an important role in the pathogenesis of focal myositis.

Adult↗
PubMed1979

Continuous muscle fiber activity: a case with unusual clinical features.

A patient with continuous muscle fiber activity is described. From our search of the literature, we believe this is the oldest patient with a reported case of this disorder, and the symptoms and treatment varied from previously reported cases in these respects: symptoms remained confined to the lower extremities after 18 months had elapsed, there was no response to phenytoin sodium or carbamazepine, and the patient required a full dose of tubocurarine chloride to stop the abnormal myoelectric potentials. A site of dysfunction in the unbranched motor axon is suggested as the locus of generation of the stimulus for the abnormal myoelectric activity.

Aged↗
PubMed1979

A familial mitochondrial myopathy with central defect in neural transmission.

A family was found to exhibit progressive external ophthalmoplegia, congenital cataracts, variable somatic weakness, gonadal dysgenesis, and, in one member, an abnormal chromosomal pattern. Muscle biopsy specimens showed "ragged-red" fibers; electron microscopy showed widespread paracrystalline mitochondrial inclusions. Orbicularis oculi reflex testing in the propositus showed bilateral absence of the late response. The family was evaluated in relation to other familial mitochondrial myopathies; a central defect in brain stem neural transmission was suggested as a mechanism for the progressive external ophthalmoplegia.

Adult↗
PubMed1979

Skeletal muscle in polymyositis. Immunohistochemical study.

Thirty-two patients with adult-onset polymyositis uncomplicated by cancer or systemic connective tissue disease were studied. Muscle biopsy specimens were examined with direct immunofluorescence microscopy and results were compared with those in 94 control subjects. Sarcolemmal and sarcoplasmic staining were observed in both groups and considered to be nonspecific. Immune deposits in the muscle microvasculature were present in some cases of systemic lupus erythematosus and dermatomyositis but were not present in polymyositis. Our data suggest that the finding of vascular immunofluorescence excludes the diagnosis of adult polymyositis and implies that the pathogenesis of this disease and other idiopathic inflammatory myopathies may differ.

Adult↗
PubMed1978

Weakness in malignancy: evidence for a remote effect of tumor on distal axons.

Malignant tumors are known to have a "remote" or nonmetastatic effect on the central and peripheral nervous systems. Eight patients were seen with proximal muscle weakness in association with bronchogenic carcinoma (5), carcinoma of breast (2), and leukemia (1). Electromyography demonstrated small polyphasic motor unit potentials. Muscle biopsy, however, showed evidence of denervation. Electron microscopy revealed morphological abnormalities in the intramuscular segments of axons. This combination of EMG and biopsy findings is presented as evidence for a remote effect of tumor on the intramuscular distal axons.

Axons↗
PubMed1978

The early effects of ischemia upon skeletal muscle mitochondria.

The effects of early ischemia were studied in the anterior tibial muscle of Sprague-Dawley rats after 2--24 hr of tourniquet compression at the thigh. Ragged-red fibers, moth-eaten fibers, cores and targets were seen in tissue examined by enzyme histochemistry and electron microscopy. Giant mitochondria, abnormalities of cristal arrangement, crystalloids, osmiophilic inclusion bodies and myeloid figures were dominant features of the mitochondrial reaction. The results of this experiment indicate that early ischemia induces a variety of changes described in other neuromuscular conditions such as dystrophy and the "mitochondrial myopathies". The pathogenesis of these changes and their relationship to human disease of muscle is discussed.

Adenosine Triphosphatases↗
PubMed1978

Phenytoin disposition in smokers and nonsmokers.

Smoking habit did not affect the disposition kinetics of intravenously administered phenytoin. Phenyoin was given to 8 smokers and 8 nonsmokers and plasma concentrations of phenytoin were determined over a three day period by GLC and RIA techniques. Nonlinear least squares computer fit of the plasma concentration-time data yielded coefficients of a biexponential equation for calculation of half-lives (t1/2beta), clearances (ClB) and volumes of distribution. There were no statistically significant differences in these parameters with respect to either sex or smoking habit. However, more variable t1/2beta's were noted in the smoking group. No differences in serum protein binding between smoking and nonsmoking groups were found. Serum thiocyanate concentrations were used as a measure of smoking habit. There was no significant correlation between thiocyanate concentrations and t1/2beta or ClB. Attemps to correlate phenytoin ClB with basal metabolic rate also failed.

Adult↗
PubMed1976

Changes in size of normal lateral ventricles during aging determined by computerized tomography.

One hundred thirty-five normal volunteers were examined by computerized tomography (CT) and their ventricular size was measured by planimetry. A pattern of change in ventricular size from the first through the ninth decades was discerned and quantified. A gradually progressive increase in ventricular size from the first through sixth decades was followed by a dramatic increase in the eighth and ninth. The range of normal ventricular size was relatively more wide in the eighth and ninth decades than in the first seven; thus, abnormalities of ventricular size may be more easily identified in younger than older subjects. These data are more valuable than those from pneumoencephalography or autopsy studies because CT is not subject to the artifact inherent in those procedures.

Adolescent↗