Enhanced alcohol-drinking behavior associated with active ghrelinergic and serotoninergic neurons in the lateral hypothalamus and amygdala.

Central ghrelin is required for the rewarding properties of drug abuse. We investigated whether alcohol affects ghrelinergic, dopaminergic, and serotoninergic neurons and growth hormone secretagogue receptor 1A (GHS-R1A) levels in the reward system of the brain. Alcohol-naïve C57BL/6J mice received 2g/kg ethanol (EtOH) intraperitoneally (i.p.). Plasma ghrelin levels decreased between 1 and 4h. We investigated the effects of EtOH administration on plasma ghrelin levels in two different animal models at 1, 3, and 10months of age. Plasma ghrelin levels decreased following the EtOH treatment in 1- and 3-month-old short-term (1-day) alcohol vapor-exposed (STA) mice. In contrast, EtOH administration increased plasma ghrelin levels in 1- and 3-month-old long-term (20-day) alcohol vapor-exposed (LTA) mice. In vivo ghrelin release in the lateral hypothalamus (LH) increased in STA and LTA mice after the i.p. administration of EtOH. EtOH increased in vivo dopamine (DA), but not serotonin (5-HT) release in the LH of STA mice, and increased in vivo DA and 5-HT release in the LH of LTA mice. GHS-R1A mRNA expression and GHS-R1A protein levels in the LH were increased in LTA mice. The number of GHS-R1A-immunoreactive cells was greater in the LH and amygdala of LTA mice. These results support the neurobiological correlation between the development of drinking behavior and activation of ghrelinergic and serotonergic neurons in the LH. The activation of ghrelinergic systems in the amygdala may also induce an increase in 5-HT release in the LH during long-term alcohol intake.

An educational training simulator for advanced perfusion techniques using a high-fidelity virtual patient model.

The operation of cardiopulmonary bypass procedure requires an advanced skill in both physiological and mechanical knowledge. We developed a virtual patient simulator system using a numerical cardiovascular regulation model to manage perfusion crisis. This article evaluates the ability of the new simulator to prevent perfusion crisis. It combined short-term baroreflex regulation of venous capacity, vascular resistance, heart rate, time-varying elastance of the heart, and plasma-refilling with a simple lumped parameter model of the cardiovascular system. The combination of parameters related to baroreflex regulation was calculated using clinical hemodynamic data. We examined the effect of differences in autonomous-nerve control parameter settings on changes in blood volume and hemodynamic parameters and determined the influence of the model on operation of the control arterial line flow and blood volume during the initiation and weaning from cardiopulmonary bypass. Typical blood pressure (BP) changes (hypertension, stable, and hypotension) were reproducible using a combination of four control parameters that can be estimated from changes in patient physiology, BP, and blood volume. This simulation model is a useful educational tool to learn the recognition and management skills of extracorporeal circulation. Identification method for control parameter can be applied for diagnosis of heart failure.

Evaluation of basic perfusion techniques, ECCSIM-Lite simulator.

Although serious accidents during extracorporeal circulation are infrequent, potential adverse events with both equipment and operation do still occur and require immediate and well-coordinated responses. Hence, perfusionists need to be well trained in both standard and emergency procedures, and this would be aided by the establishment of an official education and training curriculum. In particular, the establishment of a simulator-based educational program and corresponding evaluation methods will spur development of increasingly medical simulators. ExtraCorporeal Circulation SIMulator (ECCSIM-Lite) was used during repeated sessions of undergraduate students (n = 12) using a simple training scenario. Trainees aimed to maintain reservoir volume around a constant mean, and increase or decrease the arterial flow avoiding rapid variations, and their performance was monitored. Ability to prevent backflow was also recorded as a measure of accomplishment. Skills in performances were evaluated by using a scoring system based on task accomplishment. Accomplishment score was improved in all participants after 1 week of training. Accomplishment scores reflecting ability to maintain flow improved to an average of 78%; in the third and final practice session backflow was prevented in 100% of cases. The average reservoir level maintenance score in the flow-up phase was 75%, in the flow-maintenance phase was 92%, and in the flow-down phase was 58%. During skill training, in which trainees learn methods of avoiding adverse events, the use of simulators combined with tractable skills scores can ease the transition from training session to clinical practice. Use of these training scenarios within a perfusion education system also has the advantage of providing an index of trainees' current proficiency and improvement by providing tractable skill scores. In conclusion, the use of ECCSIM-Lite simulations, together with evaluation of task accomplishment over repeated training sessions, is an effective method of basic skill training for perfusionists.

Virtual patient simulator for the perfusion resource management drill.

Perfusionists require a detailed understanding of a patient's physiological status while comprehending the mechanics and engineering of the cardiopulmonary bypass system, so it is beneficial for them to obtain relevant practical skills using extracorporeal circulation technology and educational physiological simulators. We designed a perfusion simulator system (ECCSIM: Extracorporeal Circulation SIMulator system) based on a hybrid of a simple hydraulic mock circulation loop linked to a computer simulation model. Patient physiological conditions (height, weight, and cardiac indices) were determined by a parameter estimation procedure and used to accurately reproduce hemodynamic conditions. Extracorporeal circulation trainees in pre-clinical education were able to maintain venous oxygen saturation levels above 50%, except during cardiac standstill and a brief resumption of pulsation. Infant amplitudes of reservoir volume oscillation and flow rate were greatly increased compared with adult cardiovascular parameters, this enabled the instructor to control the difficulty level of the operation using different hemodynamic variations. High-fidelity simulator systems with controllable difficulty levels and high physiological reproducibility are useful in constructing a perfusion resource management environment that enable basic training and periodic crisis management drills to be performed.