Made available in DSpace on 2014-06-11T19:28:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-02-27Bitstream added on 2014-06-13T18:57:59Z : No. of bitstreams: 1 bitencourt_ws_me_botfm.pdf: 486980 bytes, checksum: abd8e85670c15a06e39908123b00d522 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A ativação do sistema nervoso simpático em pacientes coronariopatas pode provocar instabilidade hemodinâmica e alterações metabólicas, aumentando a incidência de isquemia ou infarto do miocárdio e graves disritmias. A resposta adrenérgica pós-operatória pode promover isquemia miocárdica devido à taquicardia, ao tempo diastólico diminuído, à vasoconstrição coronariana e ao aumento da agregação plaquetária. Pacientes submetidos à cirurgia vascular e que apresentaram isquemia miocárdica por mais de duas horas, apresentaram 32 vezes mais risco de eventos mórbidos no pós-operatório. Esforços agressivos na prevenção, ou tratamento da isquemia durante estes períodos podem melhorar o prognóstico destes pacientes. Os fármacos agonistas 2- adrenérgicos reduzem o tônus simpático, reduzindo a necessidade anestésica, e induzindo a analgesia e ansiólise (Maze, 1991), sendo uma das opções na prevenção de isquemia miocárdica peri-operatória. O objetivo desta pesquisa foi avaliar os efeitos sobre o sistema cardiovascular e concentração plasmática da vasopressina da dexmedetomidina no cão anestesiado e submetido à isquemia e reperfusão renais, empregando-se dose semelhante àquelas utilizada na anestesiologia. Vinte cães adultos, anestesiados com propofol, fentanil, isoflurano e rocurônio, foram distribuídos, de forma aleatória e encoberta, em dois grupos com 10 cães: Grupo 1 (G1): injeção de 20 ml de solução de cloreto de sódio a 0,9% em 10 minutos, seguida de injeção de 20 ml da mesma solução, em 1 hora; Grupo 2 (G2): injeção de 20 ml de solução de cloreto de sódio a 0,9% contendo dexmedetomidina 2 g.kg-1, em 10 minutos, seguida da injeção de 20 ml da mesma solução, com a mesma dose de dexmedetomidina (2 g.kg-1), em 1 hora... / The activation of the sympathetic nervous system in coronary disease patients can cause homodynamic instability and metabolic alterations, increasing the occurrences of ischemia or myocardium infarction and severe arrhythmia. The post-surgical adrenergic response can promote myocardium ischemia due to tachyarrhythmia, reduced diastolic rate, coronary vasoconstriction and the increase of platelets clogging. Patients submitted to vascular surgery and that have had myocardium ischemia for longer than two hours, presented 32 times more risks of morbid events in post-operation. Aggressive prevention efforts, or treatment of ischemia during this period can improve the prognostics of this patient. The pharmaceuticals agonists 2-adrenergics decrease the sympathetic tonus, reducing the anesthetic need, and inducing the analgesia and ansiolozy (Maze, 1991), being one of the options of myocardic ischemia peri-operational prevention. The purpose of this research was to evaluate the effects over the cardiovascular system and plasmatic concentration vasopressin of the dexmedetomidine in the anesthesiaed canine and submitted to renal ischemia and reperfusion, applying similar doses to those used in anesthesiology. Twenty adult canines, anesthesiaed with propofol, fentanil, isoflurane and rocurane, were distributed randomly and blindly, into two groups with 10 dogs each: Group 1 (G1): injection of 20 ml of 0.9% sodium chloride solution in 10 minutes, followed by the injection of 20 ml of the same solution, in 1 hour; Group 2 (G2): injection of 20 ml of 0.9% sodium chloride solution dexmedetomidine 2 g.kg-1, in 10 minutes, followed by the injection of 20 ml of same solution, with the same doses of dexmedetomidine (2 g.kg-1), in 1 hour... (Complete abstract click electronic access below)

Orientador: Geraldo Rolim Rodrigues Júnior / Banca: Norma Sueli Pinheiro Módolo / Banca: Simone Maria D'Angelo Vanni / Resumo: A ativação do sistema nervoso simpático em pacientes coronariopatas pode provocar instabilidade hemodinâmica e alterações metabólicas, aumentando a incidência de isquemia ou infarto do miocárdio e graves disritmias. A resposta adrenérgica pós-operatória pode promover isquemia miocárdica devido à taquicardia, ao tempo diastólico diminuído, à vasoconstrição coronariana e ao aumento da agregação plaquetária. Pacientes submetidos à cirurgia vascular e que apresentaram isquemia miocárdica por mais de duas horas, apresentaram 32 vezes mais risco de eventos mórbidos no pós-operatório. Esforços agressivos na prevenção, ou tratamento da isquemia durante estes períodos podem melhorar o prognóstico destes pacientes. Os fármacos agonistas 2- adrenérgicos reduzem o tônus simpático, reduzindo a necessidade anestésica, e induzindo a analgesia e ansiólise (Maze, 1991), sendo uma das opções na prevenção de isquemia miocárdica peri-operatória. O objetivo desta pesquisa foi avaliar os efeitos sobre o sistema cardiovascular e concentração plasmática da vasopressina da dexmedetomidina no cão anestesiado e submetido à isquemia e reperfusão renais, empregando-se dose semelhante àquelas utilizada na anestesiologia. Vinte cães adultos, anestesiados com propofol, fentanil, isoflurano e rocurônio, foram distribuídos, de forma aleatória e encoberta, em dois grupos com 10 cães: Grupo 1 (G1): injeção de 20 ml de solução de cloreto de sódio a 0,9% em 10 minutos, seguida de injeção de 20 ml da mesma solução, em 1 hora; Grupo 2 (G2): injeção de 20 ml de solução de cloreto de sódio a 0,9% contendo dexmedetomidina 2 g.kg-1, em 10 minutos, seguida da injeção de 20 ml da mesma solução, com a mesma dose de dexmedetomidina (2 g.kg-1), em 1 hora... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The activation of the sympathetic nervous system in coronary disease patients can cause homodynamic instability and metabolic alterations, increasing the occurrences of ischemia or myocardium infarction and severe arrhythmia. The post-surgical adrenergic response can promote myocardium ischemia due to tachyarrhythmia, reduced diastolic rate, coronary vasoconstriction and the increase of platelets clogging. Patients submitted to vascular surgery and that have had myocardium ischemia for longer than two hours, presented 32 times more risks of morbid events in post-operation. Aggressive prevention efforts, or treatment of ischemia during this period can improve the prognostics of this patient. The pharmaceuticals agonists 2-adrenergics decrease the sympathetic tonus, reducing the anesthetic need, and inducing the analgesia and ansiolozy (Maze, 1991), being one of the options of myocardic ischemia peri-operational prevention. The purpose of this research was to evaluate the effects over the cardiovascular system and plasmatic concentration vasopressin of the dexmedetomidine in the anesthesiaed canine and submitted to renal ischemia and reperfusion, applying similar doses to those used in anesthesiology. Twenty adult canines, anesthesiaed with propofol, fentanil, isoflurane and rocurane, were distributed randomly and blindly, into two groups with 10 dogs each: Group 1 (G1): injection of 20 ml of 0.9% sodium chloride solution in 10 minutes, followed by the injection of 20 ml of the same solution, in 1 hour; Group 2 (G2): injection of 20 ml of 0.9% sodium chloride solution dexmedetomidine 2 g.kg-1, in 10 minutes, followed by the injection of 20 ml of same solution, with the same doses of dexmedetomidine (2 g.kg-1), in 1 hour... (Complete abstract click electronic access below) / Mestre

Made available in DSpace on 2014-06-11T19:27:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-26Bitstream added on 2014-06-13T20:55:54Z : No. of bitstreams: 1 machado_da_me_ilha.pdf: 1511743 bytes, checksum: 02f8492fa42747b8dd47642f8ed0d7f9 (MD5) / Este projeto visa à análise cinemática de um arranjo experimental capaz de reproduzir o fluxo sanguíneo em artérias. O mecanismo procura realizar esse escoamento através de um sistema came-seguidor juntamente com um sistema hidráulico, utilizando êmbolo e duas válvulas controladoras de fluxo. O mecanismo came-seguidor será utilizado devido a sua versatilidade em garantir que o escoamento sanguíneo ocorra durante um ciclo cardíaco. A came será radial com seguidores de roletes. O seguidor de roletes será ligado ao cilindro hidráulico que controla o fluxo sanguíneo. Um tubo de látex foi acoplado ao sistema hidráulico representando a aorta abdominal, foi confeccionado com as dimensões reais desta artéria e o látex foi escolhido, pois possui um coeficiente de elasticidade muito próximo da artéria. Um manômetro foi acoplado ao sistema para medir a pressão no interior do tubo de látex. Na sequência um tubo de complacência simular as perdas de carga do sistema circulatório. O deslocamento radial do tubo de látex e variação de pressão do manômetro foram monitorados através de filmagem. Posteriormente, os resultados experimentais foram comparados e validados com os resultados numéricos obtidos com o programa ANSYS e com a literatura / This project aims to kinematic analysis of an experimental apparatus able to reproduce the blood flow in arteries. The mechanism cam-follower and the hydraulic system using piston and two controlling valves of flow were used to realize the fluid flow. The camfollower mechanism was used to ensure that the fluid flow occurs during the cardiac cycle. The cam is radial with roller followers. The follower roller is connected to the hydraulic cylinder which controls the fluid flow. A latex tube was attached to the hydraulic system representing the abdominal aorta. The latex tube has the same real dimensions of this artery and it was chosen due the modulus of elasticity very close to the artery. A manometer was used to measure the outlet pressure of latex tube. After latex tube there is a complacency tube to control the pressure drop of circulatory system. The radial displacement of the latex tube and pressure variation of the manometer were monitored through filming. The experimental results were compared and validated with numerical results obtained with ANSYS software and with literature

Cardiovascular disease is the leading cause of death with over 600,000 deaths per year. A key feature of heart failure is over stimulation of the beta-adrenergic receptors. Over stimulation of these receptors leads to changes in contractility of the heart, which can eventually lead to myocardial remodeling such as cardiomyocyte cell death (apoptosis). Prolonged activation and injury of the heart stimulates fibroblasts to repair the injured site and can lead to stiffening and scar formation. These changes in the heart are heightened in post-menopausal women as estrogen is depleted. Clinical trials have shown that estrogen has cardioprotective effects through its receptors: estrogen receptor alpha (ER-α) and estrogen receptor beta (ER-β). Though estrogen has been shown to be cardioprotective, studies have shown that hormone replacement therapy had little to no benefit to postmenopausal women with heart disease. These discrepancies lead to the need for more studies on how estrogen can protect the heart against failure. We therefore, examined the effects of estrogen deficiency and its role on cardiac structure and function following chronic β-adrenergic stimulation. Female mice (4 months of age) were treated with isoproterenol (ISO) (400μg/kg/h, subcutaneously) for 7 days one month after bilateral ovariectomy (OVX) at 3 months of age. Echocardiography and pulse wave doppler analysis was performed to examine cardiac function. Animals were then euthanized and hearts were isolated and paraffin embedded for histology analysis. Fibrosis was analyzed using Masson’s trichrome staining and apoptosis was analyzed with TUNEL assay. Ovariectomy did result in significant compromised cardiac function and ISO treatment exacerbated these results. Results from the echocardiography exam showed that ISO increased left ventricular diameter and that ovariectomy increased the diameter in a similar manner. Ovariectomized mice treated with ISO showed even greater increases in left ventricular diameter. The Doppler pattern results also showed a significant decrease in contraction time in the ISO and OVX+ISO groups compared to the OVX group alone. Surprisingly, Masson’s trichrome staining showed no significant change between the SHAM and ISO treated groups. The low amount of fibrosis could be attributed to the length of the ISO treatment. One-month post-ovariectomy may not be long enough to cause significant estrogen loss for the heart with effects on fibrosis. Extending the length of time post-ovariectomy before beginning isoproterenol treatment will be important to study the effects of estrogen loss on heart failure over time. We will analyze cardiac apoptosis and hypertrophy as further indicators of cardiac remodeling following ovariectomy and chronic beta-adrenergic stimulation. The results of this work can provide new information on heart disease in post menopausal women and alternative drug targets.

Multiple myeloma is characterized by the malignant proliferation of clonal plasma cells producing monoclonal paraproteins, leading to multi-organ damage. On the other hand monoclonal B-cell lymphocytosis (MBCL) is characterized by the malignant proliferation of clonal B-lymphocytes, with potential to develop into chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL). CLL/SLL can result in visceromegaly, anemia, thrombocytopenia, fevers, night sweats and unintentional weight loss. Literature review demonstrates these two malignant clonal bone marrow disorders are most frequently seen independently in patients; however, we report one rare diagnostic challenge where both clonal disorders were identified in a single patient concurrently. A 64-year-old man initially presented with worsening back pain. Thoracic spine x-ray revealed a T11 compression fracture, confirmed by magnetic resonance imaging. Complete blood count revealed a white blood cell count of 7.3 K/uL with 54% lymphocyte predominance and peripheral smear demonstrated a population of small lymphocytes with round nuclei and an atypical chromatin pattern suggestive of CLL/MBCL. Flow cytometry revealed a monoclonal B-cell CD5 positive, CD23 positive, CD10 negative population with an absolute count of 1.6 K/uL. Due to the instability and pain associated with the spinal fracture, patient had kyphoplasty performed and intraoperative bone biopsies were taken from both T11 and T12 vertebrae. Interestingly each bone biopsy revealed involvement by both a kappa-light chain restricted plasma cell neoplasm, ranging from 15% to 30% cellularity, as well as a CD5-positive B-cell lymphocyte population. It suggested two concurrent but pathologically distinct pathologies including plasma cell myeloma and a separate B-cell lymphoproliferative disorder with immunophenotypic features suggestive of CLL/MBCL. Bone marrow biopsy was performed for definitive evaluation and confirmed multiple myeloma with 15-20% kappa-restricted plasma cells identified, and also confirmed concurrent MBCL with CD5 and CD23-positive, kappa-restricted B-cells identified on bone marrow flow cytometry. Adding an additional layer of complexity, bone marrow molecular genetics revealed presence of a MYD88 mutation, raising concern for possible lymphoplasmacytic lymphoma (LPL). However, secondary pathologic review ruled out LPL, as the immunophenotypic pattern of the clonal B-cells was not consistent with that of LPL, and although the MYD88 mutation is predominantly seen in LPL, it has also been seen in a small percentage of CLL/SLL cases and exceedingly rarely described in MM as well. Serum protein electrophoresis with immunofixation, serum quantitative immunoglobulins and serum quantitative free light chain assay revealed findings consistent with IgG kappa multiple myeloma and systemic CT imaging was negative for any lymphadenopathy, confirming MBCL. Patient was started on first-line multiple myeloma systemic therapy for transplant eligible patients and has demonstrated an excellent response to treatment thus far. This patient case serves to demonstrate the importance of maintaining a broad differential when approaching hematological problems; It also underlines the necessity for a complete diagnostic evaluation to identify rare clinical conundrums such as with our patient, allowing for proper and timely treatment. While we use “Occam’s razor” to explain multiple problems with a single unifying diagnosis the rare possibility of divergent diagnosis is to be always entertained.

Magister Educationis - MEd / Role-play is a teaching strategy which is very useful in enhancing the acquisition of knowledge and conceptualisation of some topics in Life Science. According to the theory of constructivism, learning science is a process in which learners construct understanding of the materials. Role-play and constructivism are intertwined, yet role-play as a teaching strategy lacks classroom application in the teaching of Life Sciences. Role-play is not often used in the teaching of Life Sciences, and to be specific, in the teaching of the circulatory system. The study is motivated by learners’ misconceptions of the circulatory system. The study is undertaken to determine the effect of role play on the learners’ conception about the human circulatory system. Random sampling resulted in the selection of one out of 6 grade 10 classes with 49 learners in each from one school in the Metro East District in Cape Town.

Methamphetamine abuse is a growing global health concern. Cardiovascular disease is the leading cause of death in methamphetamine users because of its significant effects on vasoconstriction, pulmonary hypertension, atherosclerotic plaque formation, cardiac arrhythmias, and cardiomyopathy. Stimulants like methamphetamine and cocaine are known to induce severe coronary vasospasm resulting in angina and myocardial infarction (MI), but MI secondary to methamphetamine-induced coronary thrombosis is rarely reported. A 40-year-old female with medical history of immune thrombocytopenia s/p splenectomy, NSTEMI, tobacco and substance abuse presented to the hospital via EMS in an unresponsive state. Patient was admitted to the hospital 20 days before the current episode with complaints of chest pain and was diagnosed with NSTEMI due to troponin elevation without EKG changes; Echocardiogram at that time showed a left ventricular ejection fraction (LVEF) of 55-60% without any other abnormalities. Coronary angiography at that time was unremarkable except for mild luminal irregularities of the left anterior descending (LAD) artery. The patient’s symptoms resolved and was discharged home with a diagnosis of COVID-induced MI with nonobstructive coronaries. During the current episode, the patient started having crushing substernal chest pain radiating to left shoulder and associated with dizziness. She suffered cardiac arrest on the way to the hospital but was successfully resuscitated. EKG revealed anterior STEMI and the patient was loaded with aspirin. Emergent coronary angiography showed 100% occlusion of proximal LAD, while other coronaries were completely patent without any atherosclerotic plaque. A successful mechanical thrombectomy followed by a 4 x 28 mm drug-eluting stent was placed in the ostial-proximal LAD. TIMI-3 flow was restored and post-intervention troponin peaked at 70. Urine drug screen was positive for amphetamines and benzodiazepines. The echocardiogram showed a reduced LVEF of 30%. Patient was started on dual antiplatelet therapy with aspirin and ticagrelor, rosuvastatin, and low-dose metoprolol tartrate; further guideline-directed medical therapy could not be initiated due to patient’s low blood pressure. Hypercoagulability workup was negative for any abnormalities. As other usual causes were ruled out, the patient was deemed to have methamphetamine-induced coronary thrombosis resulting in myocardial infarction, and cardiomyopathy. Discussion Amphetamines are potent sympathomimetic agents that increase the risk of MI through various cardiovascular effects. Elevated serum catecholamines lead to increased heart rate, and blood pressure resulting in increased myocardial oxygen demand, while also inducing coronary vasospasm which can limit myocardial oxygen supply. Furthermore, in-vitro studies have shown amphetamines are prothrombotic as they can induce tissue factor (TF) expression, activate endothelial cells, and inhibit the activity of tissue factor pathway inhibitor (TFPI). They also increase the expression of plasminogen activator inhibitor-1 (PAI-1), a key fibrinolysis suppressant. In contrast to cocaine, amphetamines can induce thrombosis even in a non-inflamed endothelium, affecting even young individuals without atherosclerotic risk factors. These cumulative procoagulant effects may result in coronary artery thrombi as seen in our patient, which combined with other adrenergic effects, poses a significant risk for acute coronary events.

Forskning visar att läroböcker spelar en viktig roll i de naturvetenskapliga ämnena. Samtidigt riktas kritik mot lärobokens utformning där samverkan mellan människans organsystem inte visas tydligt i texter och bilder. I denna studie undersöks hur blodomloppets samverkan med andningen samt med matspjälkningen skildras i läroböckernas texter och bilder som används i grundskolans årskurs 4-6. Intervjuer med fem lärare har genomförts för att undersöka hur text och bild från läroböckerna används i undervisningen. Analyserna av läroböckerna visade att skildringen av hur blodomloppet samverkar med matspjälkningen är tydliga i lärobokens texter medan det saknas bilder på denna samverkan. Den samverkan som sker mellan blodomloppet och andningen är tydlig i både bilder och text. Intervjuerna pekade på att användandet av läroböcker är lågt i de naturvetenskapliga ämnena i grundskolans årskurs 4-6. / Research shows that the textbook plays an important role in science education. However, textbooks has been criticized because of the poor descriptions of the interaction between the human circulatory, respiratory and digestive systems. This study shows how the relationship between the circulatory system, respiratory and digestive system is described in primary school science textbooks in both texts and images. Five teachers have been interviewed to examine how they use the texts and the images from the textbooks in the classroom. Analyzes of the textbooks show that the interaction between the circulatory system and the digestive system is clearly described in texts though there is a lack of illustrative images. The interaction between the circulatory system and the respiration is clear in both images and text. The interviews showed that the use of science textbooks is scarce in primary school year 4-6.

Este trabalho se caracteriza por ser uma proposta de intervenção pedagógica construtivista, que utiliza as ideias de Jean Piaget sobre a construção do conhecimento, como diretrizes para alcançar a aprendizagem. Espera-se permitir a aprendizagem de um conteúdo específico da Ciência, que é o Sistema Circulatório (SC) e, ao mesmo tempo, a compreensão do processo de construção do conhecimento científico. Para atingir esses objetivos de aprendizagem foi construída uma sequência didática (SD). Essa SD conta com estratégias para permitir que os estudantes aprendam um conteúdo específico (SC), e participem de atividades que envolvem a História da Ciência (HC). A SD procura fatos pontuais que mostram a construção dos conceitos científicos sobre o SC, e que acima de tudo, destacam o caráter descontínuo da evolução da Ciência, entremeados por erros e acertos, ambos essenciais para prosseguir. A SD foi aplicada em um curso piloto, e os materiais produzidos pelos estudantes durante as intervenções propostas foram analisados de acordo com a \"análise discursiva textual\", no intuito de avaliar a aprendizagem em desenvolvimento e a propriedade das intervenções dentro da SD. Esta modalidade de análise foi tomada para adequar-se à natureza dos dados que se apresentavam, caracterizando uma pesquisa qualitativa. A primeira intervenção da SD foi a sondagem das concepções prévias dos estudantes, por meio de discussões em sala de aula. A segunda foi um momento de atividade prática, em que os estudantes puderam manipular nosso objeto de estudo (o elemento coração no SC). Eles receberam vários corações de galinha, e deviam analisá-los; fazer anotações e desenhos do que eles estavam observando. Depois de expressarem suas ideias, e explorarem algo concreto do SC, os estudantes receberam textos que traziam ideias distintas sobre o funcionamento deste sistema, formuladas por diferentes \"pensadores\" ao longo da HC. Muitas dessas ideias eram semelhantes às dos estudantes e outras bem distintas. Em seguida uma linha do tempo lhes foi apresentada, onde apareciam todos os pensadores dos textos anteriores, localizados na sua época. A última intervenção foi uma aula expositiva-dialogada e prática, mostrando como compreendemos o SC hoje. Depois de expor como a Ciência defende o funcionamento do SC atualmente, o coração de boi foi utilizado para mostrar estruturas importantes do coração. Foi possível perceber que existe uma forte relação entre as ideias dos estudantes e as encontradas na literatura histórica a respeito desse conteúdo. A SD permitiu em vários momentos que os estudantes fossem atores de seus próprios conhecimentos, manipulassem estruturas concretas, e tivessem acesso a ideias distintas a respeito do funcionamento do SC - muitas delas, para o contexto atual, consideradas erradas. Com isso eles se relacionaram melhor com a ideia do erro, presente tanto no contexto da HC, como no ambiente de sala de aula, o que favoreceu o processo de ensino e aprendizagem em uma perspectiva construtivista. / This work is characterized by a constructivist pedagogical intervention proposal that makes use of Jean Piaget\'s ideas of knowledge construction as ways to reach learning. It is expected that learning about a specific Science content, such as the circulatory system may be enabled simultaneously with an understanding of the scientific knowledge construction process. A didactic sequence (DS) was elaborated in order to fulfill these two learning objectives. This DS contains strategies to lead students to learn a specific content (SC) and participate in activities that involve the History of Science (HC). The DS calls the attention to points that show the building up of scientific knowledge about SC stressing the discontinuous character of science evolution with sequences of misses and hits that are both essential for progress. SD was applied to a pilot course and materials produced by students during the proposed interventions have been analysed according to the \"textual discursive analysis\", aiming to an evaluation of ongoing learning and the adequacy of interventions within the SD. This kind of analysis was used to be adequate to the nature of data, characterizing a qualitative investigation. The first DS intervention was the investigation about student\'s previous conceptions by means of classroom discussions. The second intervention involved a practice activity when students could handle our study object (the heart element at SC). They received several hicken hearts that they should analyse writing notes and drawing sketches of what was being observed. After expressing their ideas and some concrete exploration about SC, students received texts containing different ideas about his scheme that had been written by several intellectuals along HS. Many of these ideas were similar to those of students but others were quite different. Then a timeline was presented to them where all the previous texts intellectuals appeared in their epoch. The last intervention was an expositive class with dialogues and practice showing how SC is presently understood. A cow heart was then used to show the important heart structures. Is has been possible to onclude that there is a strong relation between students ideas and those that may be found in historical literature about this subject. DS often enabled students to be the actors of their own knowledge, handling concrete structures and having access to different ideas about the heart functioning- some of them to be considered as wrong in the present context. This situation led them to improvement in the idea of errors that are present in HS context but also in the classroom and this favored the teaching and learning process from a constructivist perspective.

Heart failure (HF) affects an estimated 5.8 million Americans, accounting for near 250,000 deaths each year. With shortages in available donor hearts, mechanical circulatory support (MCS) has emerged as a life-saving treatment for advanced stage HF. With growth in MCS use, a clinical and developmental need has emerged for a standard characterization and evaluation platform that may be utilized for inter-device comparison and system training. The goal of this research was to harness SynCardia's total artificial heart (TAH) to meet this need. We first sought to characterize the TAH in modern physiological terms - i.e. hemodynamics and pressure-volume loops. We then developed a model of HF using the TAH and mock circulatory system operating in a reduced output mode. We demonstrated that MCS devices could be incorporated and evaluated within the HF model. Finally, we characterized the operational envelope of SynCardia's Freedom (portable), Driver operating against varying loading conditions. Our results describe the hemodynamic envelope of the TAH. Uniquely, the TAH was found not to operate with time-varying elastance, to be insensitive to variations in afterload up to at least 135 mmHg mean aortic pressure, and exhibit Starling-like behavior. After transitioning the setup to mimic heart failure conditions, left atrial pressure and left ventricular pressure were noted to be elevated, aortic flow was reduced, sensitivity to afterload was increased, and Starling-like behavior was blunted, consistent with human heart failure. The system was then configured to allow ready addition of ventricular assist devices, which upon placement in the flow circuit resulted in restoration of hemodynamics to normal. Lastly, we demonstrated that the Freedom Driver is capable of overcoming systolic pressures of 200 mmHg as an upper driving limit. Understanding the physiology and hemodynamics of MCS devices is vital for proper use, future device development, and operator training. Characterization of the TAH affords insight into the functional parameters that govern artificial heart behavior providing perspective on differences compared to the human heart. The use of the system as a heart failure model has the potential to serve as a valuable research and teaching tool to foster safe MCS device use.