Publications by authors named "Herbert H Schaumburg"

Ethambutol is known to cause optic neuropathy and, more rarely, axonal polyneuropathy. We characterize the clinical, neurophysiological, and neuroimaging findings in a 72-year-old man who developed visual loss and paresthesias after 11 weeks of exposure to a supratherapeutic dose of ethambutol. This case demonstrates the selective vulnerability of the anterior visual pathways and peripheral nerves to ethambutol toxicity.

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The assessment of changes in sensory-motor function in clinical research presents a unique set of difficulties. Clinimetrics is the science of measurement as related to the identification of a clinical disorder, the tracing of the progression of the condition under study, and calculation of its impact. The selection of appropriate measures for clinical studies of sensory-motor function must consider validity, sensitivity, specificity, responsiveness, reliability, and feasibility.

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This study provides a detailed investigation of the anatomy of the rat caudal nerve along its entire length, as well as correlated nerve conduction measures in both large and small diameter axons. It determines that rodent caudal nerves provide a simple, sensitive experimental model for evaluation of the pathophysiology of degeneration, recovery, and prevention of length-dependent distal axonopathy. After first defining the normal anatomy and electrophysiology of the rat caudal nerves, acrylamide monomer, a reliable axonal toxin, was administered at different doses for escalating time periods.

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Background: Myeloneuropathy from chronic exposure to nitrous oxide has been described. Nitrous oxide irreversibly alters B(12) activation, causing signs and symptoms of B(12) deficiency.

Objectives: We describe a case of myeloneuropathy secondary to acute use of high-dose nitrous oxide.

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The present study explored parallel changes in the physiology and structure of myelinated (Adelta) and unmyelinated (C) small diameter axons in the cavernous nerve of rats associated with streptozotocin-induced hyperglycemia. Damage to these axons is thought to play a key role in diabetic autonomic neuropathy and erectile dysfunction, but their pathophysiology has been poorly studied. Velocities in slow conducting fibers were measured by applying multiple unit procedures; histopathology was evaluated with both light and electron microscopy.

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Objective: To illustrate the ultrastructural fibre composition of the rat cavernosal nerve at serial levels, from its origin in the main pelvic ganglion to its termination in the corpus cavernosum of the distal penile shaft, and to develop a technique that permits repeated electrophysiological recording from the fibres that form the cavernosal nerve distinct from the axons of the dorsal nerve of the penis (DNP).

Materials And Methods: For the light microscope and ultrastructural studies, Sprague-Dawley rats were anaesthetized and the pelvic organs and lower limbs were perfused with glutaraldehyde through the distal aorta. Tissue samples were embedded in epoxy resin and prepared for light and electron microscopy.

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Manganese neurotoxicity developed in a highly exposed worker after asymptomatic, moderate hepatic dysfunction from hepatitis C infection. Antiviral therapy was accompanied by resolution of increased blood manganese levels and neurologic improvement. Even asymptomatic hepatic dysfunction may impair manganese clearance and place highly exposed persons at risk for toxicity.

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Methyl bromide is toxic to the central and peripheral nervous systems. A patient with occupational exposure to this agent is described. MRI showed strikingly symmetric brainstem and cerebellar lesions.

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