RESUMEN
BACKGROUND AND PURPOSE: Although migraine is the second most disabling condition worldwide, there is poor awareness of it. The objective was to assess the awareness of migraine and previous diagnostic and therapeutic consultations and treatments in a large international population of migraineurs. METHODS: This was a multicentre study conducted in 12 headache centres in seven countries. Each centre recruited up to 100 patients referred for a first visit and diagnosed with migraine. Subjects were given a structured clinical questionnaire-based interview about the perceptions of the type of headache they suffered from, its cause, previous diagnoses, investigations and treatments. RESULTS: In all, 1161 patients completed the study. Twenty-eight per cent of participants were aware that they suffered from migraine. Sixty-four per cent called their migraine 'headache'; less commonly they used terms such as 'cervical pain' (4%), tension headache (3%) and sinusitis (1%). Eight per cent of general practitioners and 35% of specialists (of whom 51% were neurologists and/or headache specialists) consulted for migraine formulated the correct diagnosis. Before participating in the study, 50% of patients had undergone X-ray, computed tomography and/or magnetic resonance imaging of the cervical spine and 76% underwent brain and/or cervical spine imaging for migraine. Twenty-eight per cent of patients had received symptomatic migraine-specific medications and 29% at least one migraine preventive medication. CONCLUSIONS: Although migraine is a very common disease, poor awareness of it amongst patients and physicians is still an issue in several countries. This highlights the importance of the promotion of migraine awareness to reduce its burden and limit direct and indirect costs and the risk of exposure to useless investigations.
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Conocimientos, Actitudes y Práctica en Salud , Trastornos Migrañosos/diagnóstico , Trastornos Migrañosos/psicología , Adulto , Anciano , Encéfalo/diagnóstico por imagen , Estudios de Cohortes , Diagnóstico Diferencial , Errores Diagnósticos , Femenino , Cefalea/diagnóstico , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Trastornos Migrañosos/terapia , Médicos , Encuestas y Cuestionarios , Tomografía Computarizada por Rayos X , Adulto JovenRESUMEN
AIM: To evaluate the diagnostic performance of ultra-low-dose computed tomography (ULDCT) in comparison to standard coronary calcium score (CCS) acquisition for the evaluation of coronary artery calcification (CAC). MATERIALS AND METHODS: Standard CCS acquisition and ULDCT were performed in patients referred for coronary CT angiography for the evaluation of coronary artery disease. CAC in ULDCT was graded subjectively using a four-point scale (from 0, no calcification, to 3, severe calcification) for the complete study and for each individual coronary segment. The summation of all individual coronary segment scores generated an ULDCT total CAC score. ULDCT results were compared to standard Agatston score and sensitivity and specificity of ULDCT were calculated. RESULTS: CCS and ULDCT were performed in 74 patients, with a mean DLP of 77.7 mGy·cm (±12.1) and 9.3 mGy·cm (±0.6), respectively (p<0.001). Coronary calcification was detected in 47 patients (63.5%) in standard CCS acquisition (median Agatston score of 41; interquartile range [IQR]:0263), in comparison to 42 patients (56.8%) in ULDCT (p<0.001). The sensitivity and specificity of the ULDCT total CAC score ≥1 was 80.9% and 85.2%, respectively, with an accuracy of 82.4%. The area under the receiver operating characteristic curve for the presence of CAC was 0.87. CONCLUSION: ULDCT shows good sensitivity, specificity, and overall accuracy for the detection of coronary calcification with a markedly lower radiation dose in comparison to CCS. ULDCT is unlikely to miss coronary calcification in individuals with at least moderate calcium load (Agatston score >100).
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Angiografía por Tomografía Computarizada/métodos , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Calcificación Vascular/diagnóstico por imagen , Técnicas de Imagen Sincronizada Cardíacas , Enfermedad de la Arteria Coronaria/clasificación , Femenino , Humanos , Masculino , Persona de Mediana Edad , Dosis de Radiación , Interpretación de Imagen Radiográfica Asistida por Computador , Estudios Retrospectivos , Sensibilidad y Especificidad , Calcificación Vascular/clasificaciónRESUMEN
A favorable attitude of health professionals to organ donation can positively influence the decision of families of potential donors. By increasing health professionals knowledge about donation and transplantation and qualifying them to disseminate information, education has produced a positive response to increase the insufficient number of donors. Educating students early in their careers may become crucial in this setting. In order to supply the necessary information about the process of donation and transplantation, a medical school in association with the Hospital Transplant Coordination Department created an educational program of organ donation and transplantation. This course is intended for medical, biomedical, and nutrition students. The objective of our program is to supply basic knowledge about organ donation and transplantation to students of medicine, nutrition, and biomedicine and to enhance their commitment to this process. Each semester, 50 to 90 students are enrolled in the course, which involves a total of 25 hours. Various aspects are approached such as brain death, donor management, political and legal aspects of donation, and skin, lung, bone marrow, heart, pancreas, liver, and kidney transplantation. Between March 2006 and June 2007, three courses were carried out and 200 students were trained. The students evaluated the course and rated it as excellent, concluding that it contributed to their education. Their attitude toward organ donation and transplantation was strongly positive at the end of the course. This project aims to educate and stimulate students in the process of organ donation and transplantation and should be implemented in other medical schools.
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Educación de Pregrado en Medicina , Obtención de Tejidos y Órganos/normas , Muerte Encefálica , Curriculum , Familia , Educación en Salud , Humanos , Facultades de Medicina , Inmunología del TrasplanteRESUMEN
BACKGROUND: Few data are available on quality of life after surgical repair of tetralogy of Fallot (ToF), and on its relationship to right ventricle function. METHODS: Patients with at least 1 year of follow-up evaluation after surgery were studied. Right ventricle function was evaluated by the Doppler-derived myocardial performance index (MPI), and health-related quality of life (HRQL) was assessed by the Child Health Questionnaire, Parent Form-50. Findings were compared with those for an age- and sex-matched group of healthy children. RESULTS: The study enrolled 35 successfully repaired ToF patients with 4.9 years (range, 3-7 years) of follow-up evaluation after surgery and 36 healthy children. The MPI demonstrated right ventricle dysfunction in patients compared with controls (0.34; range, 0.26-0.49 vs 0.2; range, 0.13-0.27; p < 0.01), although HRQL for the psychosocial domain was similar between patients and healthy children (summary score, 47.9; range, 45-52 vs 47.5; range, 44.5-50; p = 0.17). A trend for poorer physical area results was observed in patients (summary score, 44; range, 31-52 vs 48.5; range, 45.7-51.7; p = 0.06). Neither physical nor psychosocial summary scores for HRQL had any correlation with right ventricle MPI. CONCLUSIONS: Right ventricle dysfunction is present in postoperative ToF patients. The psychosocial domain of HRQL is preserved after surgery. A trend for worse results was observed in the physical domain. The right ventricle function is not related to quality of life after surgical repair of ToF.
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Estado de Salud , Evaluación de Resultado en la Atención de Salud , Calidad de Vida , Tetralogía de Fallot/cirugía , Función Ventricular Derecha/fisiología , Niño , Preescolar , Ecocardiografía Doppler en Color , Electrocardiografía , Femenino , Estudios de Seguimiento , Ventrículos Cardíacos/diagnóstico por imagen , Ventrículos Cardíacos/fisiopatología , Humanos , Tiempo de Internación , Masculino , Periodo Posoperatorio , Estudios Retrospectivos , Tetralogía de Fallot/diagnóstico por imagen , Tetralogía de Fallot/fisiopatología , Factores de TiempoRESUMEN
OBJECTIVE: In this study, we test the hypothesis that off-pump coronary bypass surgery might result in less lymphocyte activation than on-pump coronary surgery. We also study the behavior of lymphocyte activation markers during and after surgery. BACKGROUND: Coronary artery bypass surgery is known to be associated with changes of inflammatory mediators, immune function, and early phase lymphocyte activation, which could cause postoperative lymphopenia and lymphocyte unresponsiveness. METHODS: We studied lymphocyte activation response in 28 patients randomized to off-pump (n = 13) or on-pump (n = 15) coronary artery bypass surgery. Expression of CD25, CD26, CD69, and DR on T (CD3+) and B (CD19+) lymphocytes on peripheral blood was assessed through flow cytometry. RESULTS: The response of T lymphocytes and their activation markers, as well as B lymphocytes and their activation markers, was similar after on- and off-pump surgery. Overall, T lymphocytes decreased to the lowest level 9 h after surgery and tended to increase later. For B lymphocytes, there was early reduction with increase on the 1st postoperative day. There was early activation of CD69+ and late activation of CD25+ on T lymphocytes. For B lymphocytes, there was early activation of CD69+ and late activation of DR+. CONCLUSIONS: (1) Compared to on-pump cardiopulmonary bypass, off-pump surgery does not reduce lymphocyte activation. (2) Coronary bypass surgery causes the early activation of lymphocytes, as evidenced by the increased expression of lymphocyte activation markers.
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Linfocitos B/metabolismo , Puente Cardiopulmonar , Puente de Arteria Coronaria/métodos , Enfermedad Coronaria/cirugía , Activación de Linfocitos/fisiología , Linfocitos T/metabolismo , Antígenos CD/biosíntesis , Antígenos CD19/biosíntesis , Antígenos de Diferenciación de Linfocitos T/biosíntesis , Linfocitos B/inmunología , Biomarcadores/sangre , Complejo CD3/biosíntesis , Enfermedad Coronaria/sangre , Enfermedad Coronaria/inmunología , Dipeptidil Peptidasa 4/biosíntesis , Femenino , Citometría de Flujo , Humanos , Lectinas Tipo C , Recuento de Linfocitos , Masculino , Persona de Mediana Edad , Daño por Reperfusión Miocárdica/sangre , Daño por Reperfusión Miocárdica/inmunología , Receptores de Interleucina-2/biosíntesis , Factores de Riesgo , Linfocitos T/inmunología , Resultado del TratamientoRESUMEN
We here report the case of a patient with systemic capillary leak syndrome (SCLS). This syndrome is a rare condition characterized by recurrent episodes of hypotension with hemoconcentration and hypoproteinemia. It is due to unexplained episodic capillary hyperpermeabilty that results in fluid and protein shift from the intravascular to the interstitial space: generalized edema, shock and renal failure follow. A 59 yo man was admitted to our intensive care unit because of unexplained shock with hemoconcentration, renal failure, and metabolic acidosis. Previous attemps to reverse shock in a medical ward with crystalloids and dopamine failed. An abdominal CT scan, a TEE, and chest X ray study were inconclusive. No sign or history of major infections or anaphylaxis were present. The patient was resuscitated with massive fluid infusions and norepinephrine on the guide of a Swan Ganz catheter. The diagnosis was made on the basis of a previous episode of severe shock complicated with renal failure and a compartment syndrome, the hemoconcentration, and the negative cardiopulmonary findings. A small amount of monoclonal immunoglobulin G, kappa chain, found in the serum confirmed the diagnosis. The SCLS should be considered in the differential diagnosis of idiopathic and anaphylactic shock. Patients may benefit from a prophylactic treatment with theophilline and terbutaline.
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Síndrome de Fuga Capilar/diagnóstico , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Necrotizing fasciitis is a rare soft tissue infection and a life-threatening emergency, often fatal. Its incidence and management are described plentifully in the medical literature regarding the most common anatomical sites involved like the abdomen, lower and upper limbs, and perineum. However, available data and case reports of chest wall necrotizing fasciitis after thoracic procedures are scarce, mainly after major cardiac operations. We report and discuss a case of necrotizing fasciitis of the chest wall occurring in the immediate postoperative period of a cardiac procedure, and include a brief review of the concepts, pathophysiology, and treatment reported in the medical literature. We emphasize the need for early diagnosis and urgent and effective surgical debridement. Of importance is the fact that we have not found any references in the literature to cases similar or equal to the one we describe here, which occurred in the postoperative period of a cardiac procedure.
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Fascitis Necrotizante/cirugía , Complicaciones Posoperatorias/cirugía , Infecciones de los Tejidos Blandos/cirugía , Adulto , Aneurisma de la Aorta Torácica/cirugía , Insuficiencia de la Válvula Aórtica/cirugía , Desbridamiento/métodos , Drenaje/métodos , Fascitis Necrotizante/diagnóstico , Fascitis Necrotizante/fisiopatología , Humanos , Masculino , Síndrome de Marfan/complicaciones , Complicaciones Posoperatorias/diagnóstico , Complicaciones Posoperatorias/fisiopatología , Infecciones de los Tejidos Blandos/diagnóstico , Infecciones de los Tejidos Blandos/fisiopatologíaRESUMEN
Converging evidence supports a role of serotonin (5-hydroxytryptamine; 5-HT) in barrel cortex development. Systemic administration of 5-HT-depleting drugs reduces cross-sectional whisker barrel areas in the somatosensory cortex (SSC) of neonatal rats. Here we assess the relative impact on barrel pattern formation of (i) 5-HT depletion and (ii) decreased brain growth, which is often associated with pharmacological 5-HT depletion, by comparing the effects of 5-HT-depleting drugs with those of reduced protein intake. Left hemisphere 5-HT levels in the SSC and right hemisphere whisker barrel areas were assessed at postnatal day 6 (P6) in the same animal following injection of p-chloroamphetamine (PCA) or p-chlorophenylalanine (PCPA) at P0. Both drugs significantly reduced cortical 5-HT content and mean barrel areas at P6, but also body and brain growth. Differences in brain weight accounted for 84.4% of the variance in barrel size, with negligible contributions by cortical 5-HT content. PCPA-treated animals sacrificed at P14 yielded similar trends, albeit less pronounced. Finally, reduced protein intake resulted in lower body weight and cortical 5-HT levels at P6, but yielded no change in brain weight or mean barrel area. Barrel formation therefore appears markedly less sensitive to 5-HT depletion per se than to drug-induced growth impairment.
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Fenclonina/farmacología , Serotonina/metabolismo , Corteza Somatosensorial/fisiología , p-Cloroanfetamina/farmacología , Envejecimiento , Animales , Animales Recién Nacidos , Peso Corporal/efectos de los fármacos , Encéfalo/anatomía & histología , Ácido Hidroxiindolacético/metabolismo , Tamaño de los Órganos/efectos de los fármacos , Ratas , Ratas Endogámicas Lew , Corteza Somatosensorial/efectos de los fármacos , Corteza Somatosensorial/crecimiento & desarrollo , Vibrisas/inervaciónRESUMEN
BACKGROUND: This study reports long-term results of partial left ventriculectomy (PLV). METHODS: Forty-four patients with dilated cardiomyopathy were operated on in a 4-year study. Echocardiograms, catheterization, and stress tests with oxygen consumption (VO2) were performed. RESULTS: The survivors' preoperative ejection fractions of 22.1% +/- 4.9% improved to 30.9% +/- 9.4%, left ventricular (LV) end-diastolic diameter decreased from 79.4 +/- 9.3 mm to 61.9 +/- 8.2 mm, and maximum VO2 consumption improved from 8.8 +/- 3.9 mL/kg per minute to 15.8 +/- 6.1 mL/kg per minute at 22.6 months. These data also showed improvements in nonsurviving patients, according to the last evaluation before death. Seven of 12 survivors (58.3%) were in New York Heart Association (NYHA) I and II in December 1998. Twelve patients had elevated pulmonary vascular resistance (PVR) contraindicating heart transplant. In five patients the PVR returned to normal and one high-PVR patient was transplanted at the 16th postoperative month. Survival was 56.8%, 47.7%, 38.4%, and 35.9%, respectively, at 3, 6, 12, and 18 months, with a tendency to stabilize at 32.7% thereafter. Arrhythmias and heart failure were the main causes of death. CONCLUSIONS: In spite of improvement of ventricular function and quality of life of the survivors, high mortality is a limiting factor. PLV can be indicated as a bridge to heart transplantation in high-PVR patients or if ventricular assist devices or donor hearts are not available.
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Procedimientos Quirúrgicos Cardíacos , Cardiomiopatía Dilatada/cirugía , Ventrículos Cardíacos/cirugía , Adulto , Anciano , Cardiomiopatía Dilatada/diagnóstico por imagen , Cardiomiopatía Dilatada/mortalidad , Cardiomiopatía Dilatada/fisiopatología , Femenino , Trasplante de Corazón , Hemodinámica , Humanos , Masculino , Persona de Mediana Edad , Calidad de Vida , Análisis de Supervivencia , Ultrasonografía , Resistencia VascularRESUMEN
Holt-Oram syndrome was first described in 1960 as an association of familial heart disease and musculoskeletal abnormalities. The most important findings include atrial septal defects, atrioventricular conduction abnormalities, vascular hypoplasia, and upper limb musculoskeletal deformities. We report two patients with this syndrome in the same family and discuss the variability of the musculoskeletal abnormalities and their association with the cardiac morphologic defects. Both patients in this study had associated eosinophilia, which has not been reported in the literature.
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Anomalías Múltiples/genética , Deformidades Congénitas de la Mano/genética , Cardiopatías Congénitas/genética , Pulgar/anomalías , Anomalías Múltiples/diagnóstico , Adulto , Eosinofilia/diagnóstico , Deformidades Congénitas de la Mano/diagnóstico , Cardiopatías Congénitas/diagnóstico , Humanos , Masculino , Linaje , SíndromeRESUMEN
Visual evoked potentials (VEPs) were recorded in 12 adult participants as a function of the temporal frequency of a phase-reversed checkerboard, with or without a simultaneously presented white noise. During the VEP recordings also the pulse rate was measured. VEP amplitude changed as function of temporal frequency, but it was not affected by noise. Pulse rate was stable during the session without noise, but it increased during the white noise stimulation at high temporal frequencies. Heart acceleration might be associated to conditions when processing at low levels of visual sensitivity (high temporal frequencies) is furthermore disturbed by interfering stimulation (noise).
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Estimulación Acústica , Potenciales Evocados Visuales/fisiología , Frecuencia Cardíaca/fisiología , Ruido , Adulto , Femenino , Humanos , Pulso ArterialRESUMEN
The surgical technique for partial left ventriculectomy (Batista operation) as performed in two surgical centers is described. This surgical remodeling of the left ventricle restores the abnormal geometric configuration produced by the dilated failing heart. It accomplishes a reduction of the left ventricular end-diastolic diameter and end-diastolic volume with consequent increase in left ventricular function. This procedure represents the newest surgical approach in the management of patients with end-stage cardiomyopathy; it can be used as a bridge to transplantation or perhaps as a definitive form of therapy, particularly in those patients in whom heart transplantation is contraindicated. This report describes technical guidelines to avoid serious intraoperative and postoperative complications directly associated with this technique.
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Procedimientos Quirúrgicos Cardíacos , Ventrículos Cardíacos/cirugía , Procedimientos Quirúrgicos Cardíacos/métodos , Puente Cardiopulmonar , Ecocardiografía , Estudios de Seguimiento , Insuficiencia Cardíaca/diagnóstico por imagen , Insuficiencia Cardíaca/cirugía , Ventrículos Cardíacos/diagnóstico por imagen , Humanos , Guías de Práctica Clínica como Asunto , Técnicas de Sutura , Resultado del TratamientoRESUMEN
BACKGROUND: Medically refractory heart failure is traditionally managed with cardiac transplantation although some limited success has also been obtained in selected patients using dynamic cardiomyoplasty or mechanical assist devices. Recently, a new surgical alternative called partial left ventriculectomy (PLV) was introduced by Batista in 1995. The procedure attempts to relieve symptoms of congestive failure by reducing myocardial mass and restoring the normal mass-to-volume ratio of the left ventricle. Despite initial enthusiasm, the results of PLV are not yet known. The aim of this study was to determine survival and clinical outcomes in a group of patients submitted to PLV as a means of surgical treatment for end stage heart disease (ESHD) METHODS: From November 1994 to December 1995, 15 patients with ESHD and dilated cardiomyopathy (DCM) were operated on by the technique described by Randas Batista. We compared preoperative and postoperative assessments of NYHA Functional Class (FC), Quality of Life index (QOL), echocardiographic, ergometric, radioisotopic ventriculography and hemodynamic data at intervals of zero, one, three, six and nine, and twelve months postoperatively. Kaplan-Meier, student t-test and chi-square analysis were applied to the numerical and categoric variables. RESULTS: Survival was 80% at one month, 66% at three months, 53% at six months, 47% at nine months and 40% at one year. We also found that 6 of 7 patients (85%) with tricuspid regurgitation (TR) died compared to 4 of 8 patients (50%) without TR. This was the only risk factor indentified which influenced mortality. Post-operative echocardiographic evaluations demonstrated reduced left ventricular end-diastolic and end-systolic diameters at six months (LVESD 65.5 +/- 8.3 mm preoperatively versus 56.83 +/- 5.74 mm at six months, p=0.007 and LVEDD 73.84 +/- 8.25 mm preoperatively versus 65.33 +/- 5.72 mm at six months, p=0.009). Survivors enjoyed an improved clinical status according to both the NYHA functional class (preoperative Class IV=100% versus postoperative at six months : Class IV = 50%, Class III = 17% and Class II = 33%) and the Quality of Life index (100% were in grade 6 and 7 preoperatively versus 0% at six months). However, statistical significance was not reached in most of these data due to the small number of patients. CONCLUSIONS: Actuarial survival in this series of patients was 53% at six months and 40% at twelve months with survivors showing fewer symptoms and clinical events than preoperatively (100% hospitalized preoperatively versus no patient hospitalized at six months). Therefore, the Batista Operation improves the quality of life patients with dilated cardiomyopathy and can possibly be a new means for bridging to cardiac transplantation in severely ill patients who are not likely to survive long enough to recieve a donor heart. Additional improvements in late results will likely be seen after further experience, evolution of the surgical techniques and better patient selection.
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Procedimientos Quirúrgicos Cardíacos/métodos , Insuficiencia Cardíaca/cirugía , Hipertrofia Ventricular Izquierda/cirugía , Adulto , Anciano , Brasil , Procedimientos Quirúrgicos Cardíacos/mortalidad , Distribución de Chi-Cuadrado , Femenino , Estudios de Seguimiento , Insuficiencia Cardíaca/complicaciones , Insuficiencia Cardíaca/diagnóstico , Insuficiencia Cardíaca/mortalidad , Ventrículos Cardíacos/cirugía , Humanos , Hipertrofia Ventricular Izquierda/complicaciones , Hipertrofia Ventricular Izquierda/mortalidad , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Sensibilidad y Especificidad , Índice de Severidad de la Enfermedad , Análisis de Supervivencia , Resultado del TratamientoRESUMEN
A wealth of clinical data supports a major role of genetic liability as well as of altered brain dopamine (DA) functioning in different types of behavioural disturbances. Genetic influence on behaviour involves multiple genes, rather than one or two major genes, as well as non-genetic sources of variance. Thus, in recent years, increasing attention has been devoted to the involvement of stressful experiences (life events) in the development and expression of psychopathology. Moreover, a diathesis-stress hypothesis has been proposed, which suggests that the environmental factors (stress) are not specific for a given pathology, whereas genetic factors (diathesis) are. Results obtained in an animal model offer support to this hypothesis. Indeed, mice of the C57BL/6 and DBA/2 inbred strains are equally susceptible to stress but develop different behavioural disturbances related to different alterations of brain DA receptors. Moreover, quantitative trait loci (QTL) associations in the C57 (B) x DBA (D) recombinant inbred (RI) strains indicate a number of provisional QTLs influencing the behavioural effect of stress. Finally, the results of this analysis suggest the involvement of regulatory factors related to stress response and neural or synaptic plasticity in the control of brain DA receptor plasticity.
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Apomorfina/farmacología , Conducta Animal/efectos de los fármacos , Agonistas de Dopamina/farmacología , Predisposición Genética a la Enfermedad , Estrés Fisiológico/genética , Animales , Conducta Animal/fisiología , Mapeo Cromosómico , Susceptibilidad a Enfermedades/fisiopatología , Marcadores Genéticos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos DBA , Fenotipo , Receptores Dopaminérgicos/efectos de los fármacos , Estrés Fisiológico/fisiopatologíaRESUMEN
Para o tratamento da incompetência cronotrópica, marcapassos com adaptaçäo em freqüência baseados em diferentes sinais de sensores têm sido desenvolvidos, visando restaurar o mecanismo fisiológico em malha fechada e utilizando informaçäo fornecida pelo sistema nervoso autônomo (SNA). A medida da impedância cardíaca unipolar permite a monitorizaçäo do estado de contraçäo do coraçäo, diretamente relacionado ao tônus simpático. Marcapassos uni ou bicamerais com sistemas responsivos controlados pelo SNA foram implantados em 262 pacientes em vários centros clínicos. Protocolos de exercícios clíncos, monitorizaçäo por Holter, testes de estresse psicológico e estudos adicionais visando uma variaçäo intencional do tônus simpático confirmaram a resposta fisiológica em freqüência para os vários tipos de mudanças hemodinâmicas.