Browsing by Author "Tapia, Luis"
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Item Descripción Histológica de los Diferentes Segmentos del Aparato Respiratorio de Avestruz (Struthio camelus var. Domesticus)(Sociedad Chilena de Anatomia, 2014) Illanes, Julio; Leitchle, Jorge; Leyton, Victor; Tapia, Luis; Fertilio, Bárbara; Castro, MarioDue to the growing interest of the ostrich industry (Struthio camelus var. domesticus) and the scarce bibliographic material related to morphology of the respiratory system of the ostrich, we carried out a comparative analysis of the laryngotracheal pulmonary segment of this bird. The research was conducted in six clinically healthy ostriches from which representative samples of the laryngotracheal pulmonary segment were obtained. Samples were processed using standard histological technique and a comparative morphological analysis between ostriches and chicken (Gallus gallus) was performed. In the ostrich, the arytenoid cartilage is double and placed in a dorsal and cranial position in relation to the larynx while the cricoid cartilage is single and situated in a ventral and caudal position. Like the chicken, the procricoid cartilage is also present. The trachea exhibits a greater number of rings compared to the chicken. At the syrinx level, the pessulus is made up of a dorso-ventral double-fold of mucous membrane with a lamina propria of dense connective tissue over a thick adipose layer. Unlike the chicken the ostrich pessulus does not contain any ossified or cartilaginous tissues. The mucosa between the larynx and secondary bronchi has a pseudostratified prismatic ciliated epithelium with mucous goblet cells with crypts and simple tubuloalveolar mucosal glands for mucous secretion. In the extrapulmonary primary bronchi this histological feature is observed only in the medial aspect where the ends of the cartilaginous rings are found. The remaining mucosa of these bronchi has a pseudostratified prismatic ciliated epithelium with mucous goblet cells. Aerial sacs show this histological feature in some sectors.Item Evidence of hysteresis in propofol pharmacodynamics(John Wiley & Sons, 2017) Sepúlveda, Pablo; Carrasco, E; Tapia, Luis; Ramos, Mario; Cruz, F; Conget, Paulette; Olivares, Q; Cortinez, IIt is commonly assumed that loss of responsiveness and recovery of responsiveness occur at similar concentrations of propofol. However, the 'conscious' and 'anaesthetised' conditions produced by general anaesthetics may behave as two bistable states. We hypothesised that loss of responsiveness and recovery of responsiveness occur at different propofol concentrations. Propofol was administered to 19 healthy volunteers by effect-site target-controlled infusion using increasing and decreasing stable concentration steps of 7 min. Propofol serum concentrations were measured from venous blood samples at the end of each 7-min step. A long step of 14 min was performed at loss of responsiveness. At this step, propofol concentrations were measured at 7 and 14 min. Propofol concentrations measured at loss of responsiveness and recovery of responsiveness were 2.6 (1.2-4.7) μg.ml-1 and 1.6 (0.6-3.3) μg.ml-1 , respectively (p < 0.001). Propofol plasma concentration and the corresponding bispectral index values measured at minute 7 and minute 14 of the long step performed at loss of responsiveness were 2.6 (1.2-4.7) vs. 2.6 (1.3-4.3) at recovery of responsiveness, (p = 0.96) and 61.2 (49.0-77.0) vs. 58.4 (45.0-74.0), (p = 0.058), respectively. Loss of responsiveness and recovery of responsiveness appear to occur at different propofol concentrations. However, it is possible that, if equilibration was not achieved between plasma and effect-sites at the end of each 7-min step, the higher concentrations found at loss of responsiveness compared with those observed during recovery of responsiveness could be explained by a possible bias in estimations of the effect-site concentrations of propofol by the Schnider model, rather than neural inertia.