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Biomedical subjects

L Z Stern

Publications and source records attributed to L Z Stern.

At least 55 records · Page 3Linked to original sources

Conduction velocities in single fibers of diseased human muscle.

Focal sarcolemmal lesions, segmental degeneration, and fiber splitting are observed in Duchenne muscular dystrophy and have been proposed to be major contributory causes of dysfunction of this disease. The presence of these abnormalities should affect impulse conduction along the sarcolemma. To test this prediction, we measured conduction velocities of the action potential in normal and diseased human intercostal muscle fibers by means of intracellular microelectrodes. The resting potentials of fibers from patients with Duchenne dystrophy, Becker dystrophy, and motor neuron disease were partially depolarized, and conduction velocities in these fibers were slower than normal. When the membrane potential was artifically hyperpolarized, the conduction velocity in Becker dystrophy fibers was not significantly different from normal. However, conduction velocity values in Duchenne dystrophy or motor neuron disease fibers were significantly lower than normal regardless of the level of membrane hyperpolarization. These data are analyzed in light of the presence of morphologic lesions in the diseased muscle fibers.

Action Potentials↗

Abnormal iris vasculature in myotonic dystrophy. An anterior segment angiographic study.

The microvasculature of the iris was studied in 35 patients with neuromuscular disease and 14 control subjects, using anterior segment fluorescein angiography. Myotonic muscular dystrophy, in which a variety of ocular changes have previously been reported, was found to be associated with both focal and generalized vascular abnormalities. Changes were seen in the fluorescein angiograms of all nine of the myotonic dystrophy patients in which the iris vessels could be seen. No evidence of a microcirculatory disorder was seen in patients with Duchenne's dystrophy, for which a vascular pathogenesis has been proposed. The angiograms of patients with limb-girdle dystrophy, facioscapulohumeral dystrophy, and Friedreich's ataxia were also normal.

Adult↗

Steroid myopathy.

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Adrenal Cortex Hormones↗

Cerebrospinal fluid gamma-aminobutyric acid variations in neurological disorders.

Neuropathologically, Huntington's disease is characterized by a profound reduction in neuronal cells originating in the corpus striatum and globus pallidus. Since one of these cell types utilizes gamma-aminobutyric acid (GABA) as a neurotransmitter, it may be possible to differentially diagnose this disorder on the basis of the CSF content of this amino acid. In order to determine the validity of this hypothesis, cerebrospinal fluid GABA was analyzed, using a recently developed radioreceptor assay procedure and was found to be significantly reduced in patients diagnosed as having Huntington's disease and also lower in patients with Alzheimer's disease, though no difference was noted between Parkinson patients and control subjects. The results suggest that analysis of cerebrospinal fluid GABA may have diagnostic, and perhaps predictive, value in certain neurological disorders.

Adolescent↗