Neuropathology of the antischistosomal agent amoscanate administered in high oral doses to rats.

Amoscanate is a highly effective antischistosomal agent when administered as a 5% absorbable aqueous suspension. This preparation produces lesions in the brains of young adult rats given extremely high oral doses. Lesions are confined to areas adjacent to the lateral ventricles and are dominated by necrosis of the neuropil of the medial striatum, with relative sparing of bundles of myelinated fibers in the necrotic zone. There is a striking accumulation of calcium-containing microgranules in these areas. The ependyma survives on the ventricular wall overlying the necrotic zone, but pyknosis and increased extracellular space are apparent among ependymal and subependymal cells in the region. Occasionally, fibers of the fornix are focally damaged in immediate proximity to the lateral ventricle; the corpus callosum is rarefied, and microhemorrhages also occur. It is hypothesized that high concentration of the toxic agent in ventricular cerebrospinal fluid plays an important role in pathogenesis. The neuropil of the medial striatum is selectively vulnerable.

Unilateral Duane's retraction syndrome (Type 1).

Duane's retraction syndrome (DRS) is a congenital eye movement disorder characterized by adduction deficiency, abduction limitation, globe retraction, and palpebral fissure narrowing on attempted adduction. In a case of unilateral DRS, the right side of the brainstem, cavernous sinus, and orbit were completely normal. The left abducens nucleus contained no cell bodies from motor neurons, but in its rostral portion, it contained several small cell bodies believed to be compatible with internuclear neurons. The left abducens nerve was absent. The left lateral rectus muscle was partially innervated by branches from the inferior oculomotor nerve.