The role of the habenular complex in the elevation of dorsal raphe nucleus serotonin and the changes in the behavioral responses produced by uncontrollable stress.

Previous research indicates that the serotonergic neurons of the caudal dorsal raphe nucleus (DRN) are activated to a greater degree by inescapable shock (IS) as compared to escapable shock (ES), causing a greater release of serotonin (5-HT) in the DRN and in target regions. This differential activation is necessary for the behavioral changes that occur after exposure to IS, but not to ES (i.e. learned helplessness/behavioral depression). Although the critical role of the DRN in learned helplessness is clear, the neural inputs to the caudal DRN which result in this selective activation are unknown. One structure that may be involved in the activation of the DRN and the induction of learned helplessness/behavioral depression is the habenular complex. In experiment 1, habenula lesions eliminated the differential rise in DRN extracellular 5-HT levels in response to IS and ES exposure by severely attenuating the rise in 5-HT for both groups. In experiment 2, sham operated and habenula lesioned rats were exposed to either ES, IS or no stress (home cage control; HCC). Twenty-four hours later, sham rats previously exposed to IS exhibited longer escape latencies as compared to both ES and HCC rats (i.e. learned helplessness). The habenular lesion eliminated the differences in escape latency between groups, thus eliminating the induction of learned helplessness/behavioral depression. These results suggest that the habenula is necessary for the differential activation of the DRN and the escape deficits produced by IS.

Escapable and inescapable stress differentially alter extracellular levels of 5-HT in the basolateral amygdala of the rat.

The effects of escapable and yoked inescapable electric tailshocks on extracellular levels of serotonin (5-HT) in the basolateral amygdala were measured by in vivo microdialysis. Inescapable, but not escapable, shock increased extracellular 5-HT in the amygdala relative to restrained controls. Basal levels of 5-HT were elevated 24 h after inescapable shock, and previously inescapably shocked subjects exhibited an exaggerated 5-HT response to two brief footshocks. Levels of extracellular 5-HIAA did not follow any particular pattern and were not correlated with the changes in 5-HT.

Escapable and inescapable stress differentially and selectively alter extracellular levels of 5-HT in the ventral hippocampus and dorsal periaqueductal gray of the rat.

The effects of escapable and yoked inescapable electric tailshocks on extracellular levels of serotonin (5-HT) in the ventral hippocampus and dorsal periaqueductal gray (dPAG) were measured by in vivo microdialysis. Inescapable, but not escapable shock increased extracellular 5-HT in the ventral hippocampus relative to restrained controls. Basal levels of 5-HT were elevated 24 h after inescapable shock, and previously inescapably shocked subjects exhibited an exaggerated 5-HT response to 2 brief footshocks. In contrast, escapable, but not inescapable shock, increased extracellular 5-HT in the dPAG, increased basal 5-HT in the dPAG 24 h later, and led to an enhanced 5-HT response to subsequent brief footshock.

Colecistectomía laparoscópica en pacientes con cirugía del abdomen superior / Laparoscopic cholecystectomy in patients with upper abdominal surgery

Hasta hace poco tiempo, la existencia de cirugía previa en el abdomen superior era una contraindicación para practicar la colecistectomía laparoscópica. Presentamos nuestros 12 primeros pacientes operados, 10 mujeres y 2 hombres. La cirugía previa más frecuente practicada fue la gástrica por úlcera duodenal. En el 83,4 por ciento se completó el procedimiento, con un índice de conversión del 16,6 por ciento. No hubo morbilidad ni mortalidad. Como conclusión, la existencia de cirugía previa en el abdomen superior no contraindica la CL. Se requiere eso sí, una mayor experiencia en la técnica laparoscópica y un instrumental más completo.

Tratamiento paliativo del cáncer de esófago irresecable / Palliative treatment of the irresecable esophageal cancer

En nuestro medio el cáncer esofágico sigue diagnosticándose tardíamente, por lo cual el tratamiento quirúrgico con intención resectiva no excede el 30 por ciento. Al resto de los pacientes sólo se les puede ofrecer tratamientos paliativos. De un total de 224 enfermos portadores de esta localización de cáncer, 170 accedieron a esta última alternativa de tratamiento. Dilataciones periódicas, gastrostomías, prótesis endoluminales o puentes con ascenso de estómago o de un segmento de intestino grueso fueron los procedimientos terapéuticos utilizados en esta serie, motivo de este estudio. De ellos, la dilatación periódica es el que presenta menor morbimortalidad, y los procedimientos de puente están indicados cuando los pacientes en buenas condiciones generales presentan intensa disfagia, y la operación les permite una mejor calidad de vida en el corto o mediano plazo de sobrevida

[Morphologic substrates of the ventricular route of secretion and transport of substances in the tubero-infundibular region of the hypothalamus. Ultrastructural study]. / Sustratos morfológicos de la vía ventricular de secreción y transporte de sustancias en la región tuberoinfundibular del hipotálamo. Estudio ultraestructural.

Ultrastructural studies of the ependyma of the tuberoinfundibular region of the rat hypothalamus have revealed the existence of intraventricular axonal endings and of cytoplasmic blebs and bulbs that project from the apical surface of the ependymal cells to the ventricular lumen. All these structures account for the processes of ependymal apocrine secretion and the neuroventriculocrinia, and hence the release of biologically active substances into the cerebrospinal fluid (CSF). These substances contained in the CSF must act on the nervous nuclei of the tuberoinfundibular region, such as the arcuate nucleus, which is very important in the neuroendocrine regulation of the anterior pituitary gland. Dilated intercellular spaces among neighbouring ependymocytes of this region, small intraependymal cisternae and, in particular, a lateral prolongation of the infundibular recess, which courses through the nervous tissue between the arcuate nucleus and the median eminence from the vertex of the lateral angle of the infundibular recess, may be the route followed by the CSF from the third ventricle to the tissue compartment of the tuberoinfundibular region. Also studied are the cisternae of the region and the relationships of these with the lateral prolongation of the infundibular recess. Some of these cisternae may be filled by the CSF through the prolongation. In this way, the tissue compartment of CSF would be enlarged, and hence the ventricular route for the secretion and transport of biologically active substances would be potentiated.

Sustratos morfológicos de la vía ventricular de secreción y transporte de sustancias en la región tuberoinfundibular del hipotálamo: estudio ultraestructural / Morphologic substrates of the ventricular route of secretion and transport of substances in the tubero-infundibular region of the hypothalamus: ultrastructural study

Ultrastructural studies of the ependyma of the tuberoinfundibular region of the rat hypothalamus have revealed the existence of intraventricular axonal endings and of cytoplasmic blebs and bulbs that project from the apical surface of the ependymal cells to the ventricular lumen. All these structures account for the processes of ependymal apocrine secretion and the neuroventriculocrinia, and hence the release of biologically active substances into the cerebrospinal fluid (CSF). These substances contained in the CSF must act on the nervous nuclei of the tuberoinfundibular region, such as the arcuate nucleus, which is very important in the neuroendocrine regulation of the anterior pituitary gland. Dilated intercellular spaces among neighbouring ependymocytes of this region, small intraependymal cisternae and, in particular, a lateral prolongation of the infundibular recess, which courses through the nervous tissue between the arcuate nucleus and the median eminence from the vertex of the lateral angle of the infundibular recess, may be the route followed by the CSF from the third ventricle to the tissue compartment of the tuberoinfundibular region. Also studied are the cisternae of the region and the relationships of these with the lateral prolongation of the infundibular recess. Some of these cisternae may be filled by the CSF through the prolongation. In this way, the tissue compartment of CSF would be enlarged, and hence the ventricular route for the secretion and transport of biologically active substances would be potentiated

Obstrucción mecánica de intestino delgado: análisis de parámetros pronósticos / Mechanical obstruction of low intestine: analysis of prognostic parameters

Se analizan retrospectivamente 147 casos de obstrucción mecánica de Intestino delgado, entre los años 1986-1988. De ellos, un 54% son mujeres y 46% hombres. Se analizan diversos parámetros clínicos y de laboratorio para establecer la probabilidad de necrosis intestinal. De ellos, el único que demuestra utilidad es la desviación izquierda mayor de 20%. Las etiologías principales fueron bridas (63%) y hernias (23%). La morbilidad general fue de 39% y la mortalidad de 7,5%