RESUMEN
Paciente de 32 años, que ingresa a la sala de guardia por sufrir poliltraumatismo secundario a accidente automovilístico. Se le realiza Rx de tórax que evidencia ensanchamietno de mediastino con sospecha clínica y por estudios con TAC y ecotransesofágico de rotura de aorta torácica, confirmada por angiografía de aorta descendente que muestra una imagen compatible con pseudoaneurisma. Debido a que la paciente persiste hipotensa, se decide tratamiento inmediato por vía endovascular, colocando un stent graft expandible con balón, con resultado exitoso y sin complicaciones. En el seguimiento con TAC con contraste al mes, a los 6 meses y al año, no se observaron alteraciones de la prótesis ni leaks peri protésico o re-estenosis. Palabras clave: Stent graft, ruptura traumática, pseudoaneurisma, accidente de tráfico.
Asunto(s)
Humanos , Adulto , Femenino , Accidentes de Tránsito , Aorta Torácica/cirugía , Aorta Torácica/lesiones , Procedimientos Quirúrgicos Cardiovasculares , Traumatología , Procedimientos Quirúrgicos Vasculares , ArgentinaRESUMEN
We endeavored to determine whether three behavioral effects of melatonin in rodents, i.e., depression of locomotor activity in hamsters, analgesia in mice, and impairment of 3-mercaptopropionic acid (3-MP) convulsions, exhibited the time dependency known to occur for several neuroendocrine effects of the hormone. Activity was monitored and registered by means of an optical actometer, and analgesia was assessed by the hot-plate procedure. Locomotor activity, analgesia, and seizure susceptibility were maximal at the beginning of the scotophase and minimal at noon. The effects of melatonin on the three parameters peaked at early night. The administration of the benzodiazepine antagonist flumazenil, although unable by itself to modify locomotor activity, pain, or seizure threshold, blunted the activity of melatonin. These results suggest that the time-dependent effects of melatonin on specific rodent behaviors may be mediated by central synapses employing gamma-aminobutyric acid (GABA) as an inhibitory transmitter.
Asunto(s)
Conducta Animal/efectos de los fármacos , Ritmo Circadiano/fisiología , Melatonina/farmacología , Animales , Ritmo Circadiano/efectos de los fármacos , Cricetinae , Flumazenil/farmacología , Masculino , Melatonina/antagonistas & inhibidores , Mesocricetus , Ratones , Actividad Motora/efectos de los fármacos , Dimensión del Dolor , Convulsiones/inducido químicamenteRESUMEN
The aim of the present study was to determine whether melatonin-induced depression of locomotor activity in hamsters is time-dependent and to analyze the inhibitory effects of the central-type benzodiazepine (BZP) antagonist Ro 15-1788 on melatonin-induced depression of locomotor behavior. Activity was monitored and registered by means of an optical actometer. Two phases of locomotor behavior were found. The initial phase, found both at noon and during the evening, exhibited an absence of diurnal variability, while a second long-lasting phase of activity exhibited a peak at early night. The IP injection of melatonin (minimal effective dose: 100 micrograms/kg) inhibited the early phase of activity at 1200 or 2000 h. Inhibition of the late phase of activity was found at 2000 or 0400 h, but not at midnight. When assessed at 2000 h, melatonin depression of the early phase of locomotor activity attained significance after 5 days of injection, while its effect on the late phase of activity attained significance during the second day of injection. The administration of Ro 15-1788, although unable by itself to modify locomotor activity, significantly attenuated the inhibitory effects of melatonin. These results indicate the existence of a time-dependency for melatonin activity on locomotor behavior similar to that known to occur for other effects of the hormone, and further support a link between melatonin and the activity of central type BZP receptors.
Asunto(s)
Encéfalo/efectos de los fármacos , Ritmo Circadiano/efectos de los fármacos , Flumazenil/farmacología , Antagonistas de Receptores de GABA-A , Melatonina/farmacología , Actividad Motora/efectos de los fármacos , Animales , Cricetinae , Relación Dosis-Respuesta a Droga , Melatonina/antagonistas & inhibidores , MesocricetusRESUMEN
The aim of this study was to determine whether melatonin-induced analgesia in mice exhibits the time dependency known to occur for several other effects of the hormone, and to analyze to what extent the activity of melatonin can be inhibited by the opiate antagonist naloxone or the central-type benzodiazepine (BZP) antagonist Ro 15-1788. Analgesia was assessed with the hot plate procedure. There was a significant diurnal variation in the pain threshold, with an increase in latency during the dark phase of the daily photo period. Melatonin (20-40 mg/kg i.p.) exhibited maximal analgesic effects at late evening (20:00 h). The administration of naloxone or Ro 15-1788 at 20:00 h, although unable by themselves to modify pain threshold, blunted the analgesic response to melatonin. Significant increases in the latency of the hot plate response were found after diazepam injection, an effect blocked by Ro 15-1788 or naloxone. These results indicate that time-dependent melatonin analgesia is sensitive to opioid or central-type BZP antagonism.