Scanning electron microscopy of the floor of the fourth ventricle in rats subjected to graded impact injury to the sensorimotor cortex.

OBJECT: Respiratory dysfunction including apnea frequently follows head injury in humans. The purpose of this study was to identify any structural alterations in the region of brainstem respiratory nuclei that might account for immediate postinjury respiratory abnormalities in anesthetized experimental animals. METHODS: Using scanning electron microscopy, the authors examined the floor of the fourth ventricle in injured rats after a piston strike to the sensorimotor cortex that depressed the dura 1, 2, or 4 mm. The rats were killed within minutes of injury. Cortical impact depths measuring either 1 or 2 mm (eight rats) produced no respiratory abnormalities, and the structural integrity of the ependymal lining of the ventricular floor in these animals was not compromised. Thirteen rats were subjected to impact to a 4-mm depth and 10 of these exhibited immediate temporary or permanent apnea. The medullae of nine of these rats were studied using scanning electron microscopy, and the fourth ventricular floors of all nine rats showed tears. Four rats that exhibited immediate, permanent apnea had tears in the caudal fourth ventricle floor near the obex, whereas five rats with no or only transient apnea had tears located more anteriorly, near the aqueduct or laterally. Changes in cerebrospinal fluid flow or pressure dynamics may have caused these tears. Light microscopy, focused near the area postrema, revealed a shearing defect through the ependyma of the fourth ventricular floor into the subjacent neuropil with a disruption of axonal pathways. CONCLUSIONS: Respiratory neuronal network components lying within 2 mm of the area postrema may well have been disrupted by the caudal tears producing permanent apnea. A similar phenomenon could account for the transient or permanent postinjury apnea seen in humans with severe head injury.

Síndromes neurocutáneos: neurofibromatosis tipo - I / Neurocutaneus syndrome: neurofibromatosis type - I

Se expone la importancia del conocimiento de los aspectos clínicos y genéticos de los diferentes transtornos Neurocutáneos. Presentamos la serie personal del Profesor I. Pascual Castroviejo, de pacientes en el Servicio de Neurología Infantil a lo largo de 23.5 años. Esta serie está constituida por 174 casos de NEUROFIBROMATOSIS, 139 casos de Esclerosis Tuberosa, 48 casos de Incontinencia Pigmentaria Acromiante de Ito, 41 casos de síndrome de Stuger-Weber, 14 casos de Nevus Sebaceous de Jadassohn, 8 casos de Cutis Marmorata Telangiectásica congénita, 8 casos de Angioma Capilar, 8 casos de Melanosis Neurocutánea, 6 casos de síndrome de Sjogren-Larsson, 4 casos de Neuvus Fuscuceruleous de Ota, 3 casos de Incontinencia Pigmenti, 2 casos de síndrome de Goltz y 1 caso de Displasia Cerebelotrigeminal. Exponemos un seguimiento de 15 casos de NEUROFIBROMATOSIS TIPO - I entre Enero y Julio de 1990.