Clinical Application of Exercise Stress Echocardiography in an Outpatient Pediatric Population.

Background: Exercise stress echocardiography (ESE) is commonly employed in adults, but its applicability in pediatric populations remains to be clarified. Methods: A total of 309 consecutive children (C), with a mean age of 14.1 ± 2.6 years (range 6-17 years), underwent treadmill ESE starting in 2002. They were divided into two groups: Group I comprised 258 children, including 237 with symptoms related to exercise (such as chest pain, fatigue, lipothymia/syncope, or one aborted sudden death), 15 with electrocardiogram (ECG) abnormalities, and 6 with a positive ECG stress test showing ST changes. Group II consisted of 10 asymptomatic children whose parents requested routine screening, 11 with symptoms unrelated to exercise, 12 with a family history of sudden death, and 17 with known pathologies (including 10 with hypertrophic cardiomyopathy, 2 with aortic coarctation, and the remainder with various conditions, such as Cortriatriatum sinister, pulmonary stenosis, subaortic stenosis, bicuspid aortic valve, left ventricular hypertrophy related to arterial hypertension, and aortic switch operation). Regional wall motion abnormalities (RWMAs) and transvalvular or intraventricular (IVG) gradients were assessed using 2D and continuous-wave Doppler, respectively, in all cases. Results: The success rate was 100% (309/309). Stress-induced RWMAs were observed in two children. A significant IVG (>30 mmHg) was detected in 101 out of the 258 children (39%) in Group I, who presented with exercise-related symptoms, ECG abnormalities, or positive stress ECG. In Group I, the odds ratio (OR) of ESE reproducing the symptoms in children with IVG compared to those without IVG was 8.22 (95% CI: 4.84-13.99, p < 0.001). Conclusions: Treadmill ESE is both feasible and safe for pediatric populations. RWMAs demonstrated limited utility in our cohort of children, while IVG induced by exercise was frequently observed in symptomatic children.

Exercise-Induced Intraventricular Gradients As a Potential Cause of Sudden Cardiac Death.

A 16-year-old boy reported an episode of dizziness related to intense training six months before an episode of aborted sudden death. The screening required for competitive sports practice was normal. There were no personal or familial antecedents of sudden death or heart disease. After winning a triathlon competition, he experienced a cardiac arrest episode. He received defibrillation with the return of spontaneous circulation. A medical evaluation that included electrocardiogram (ECG) and echocardiogram had normal results. A complete study including cardiac MRI, coronary CT angiography, a genetic study for heart disease, the flecainide test, and a stress echocardiogram with ergometrine was done, and all results were normal. During a Holter ECG and exercise stress echo, isolated premature ventricular complexes were detected. During the effort treadmill stress echocardiogram, the athlete developed a significant intraventricular obstruction with an end-systolic peak, without systolic anterior movement of the mitral valve, which disappeared in the first minute of the recovery. We highlight the possible cause-effect relation between the events.

Microvascular Dysfunction Is Associated With Impaired Myocardial Work in Obstructive and Nonobstructive Hypertrophic Cardiomyopathy: A Multimodality Study.

Background Two-dimensional speckle tracking echocardiography has been shown to correlate with microvascular dysfunction, a hallmark of hypertrophic cardiomyopathy (HCM). We hypothesized that there is an association between myocardial work and left ventricular ischemia, with incremental value to global longitudinal strain, in patients with HCM. Methods and Results We performed a prospective assessment of patients with HCM, undergoing 2-dimensional speckle tracking echocardiography and stress perfusion cardiac magnetic resonance. Results were stratified according to obstructive or nonobstructive HCM and the presence of significant replacement fibrosis (late gadolinium enhancement ≥15% of left ventricular mass). Seventy-five patients with HCM (63% men, age 55±15 years) were evaluated, 28% with obstructive HCM (mean gradient 89±60 mm Hg). Perfusion defects were found in 90.7%, involving 22.5±16.9% of left ventricular mass, and 38.7% had late gadolinium enhancement ≥15%. In a multivariable analysis, a lower global work index (r=-0.519, ß-estimate -10.822; P=0.001), lower global work efficiency (r=-0.379, ß-estimate -0.123; P=0.041), and impaired global constructive work (r=-0.532, ß-estimate -13.788; P<0.001) significantly correlated with ischemia. A segmental analysis supported these findings, albeit with lower correlation coefficients. A global work index cutoff ≤1755 mm Hg% was associated with hypoperfusion with a sensitivity of 88% and a specificity of 71%, while the best cutoff for global longitudinal strain (>-15.5%) had a sensitivity of 64% and a specificity of 57%. The association between myocardial work and perfusion defects was significant independently of late gadolinium enhancement ≥15% and obstructive HCM. Conclusions Impaired myocardial work was significantly correlated with the extent of ischemia in cardiac magnetic resonance, independently of the degree of left ventricular hypertrophy or fibrosis, with a higher predictive power than global longitudinal strain.

Intraventricular gradients-When we have to "exercise" our minds: A case report.

Increased intraventricular pressure gradients due to dynamic left ventricular outflow tract obstruction during exercise have long been known to cause different symptoms. Exercise stress echocardiography is fundamental in the diagnostic approach of symptoms presenting during exercise. We hypothesize on the possible pathophysiological mechanisms responsible for our patient's syncopal episodes.

Associations between perfusion defects, tissue changes and myocardial deformation in hypertrophic cardiomyopathy, uncovered by a cardiac magnetic resonance segmental analysis.

BACKGROUND: Microvascular dysfunction is an often overlooked feature of hypertrophic cardiomyopathy (HCM). Our aim was to assess the association between microvascular dysfunction, wall thickness, tissue characteristics and myocardial deformation in HCM patients, by analyzing individual myocardial segments. METHODS: Prospective assessment including cardiac magnetic resonance to assess wall thickness, T1 and T2 mapping, extracellular volume, late gadolinium enhancement (LGE) and stress perfusion. Results were stratified according to the 16 American Heart Association segments. RESULTS: Seventy-five patients were recruited (1200 segments), 63% male, mean age 54.6±14.8 years, maximal wall thickness of 20.22±4.6 mm. Among the 424 segments (35%) with perfusion defects, 24% had defects only in the endocardial layer and 12% in both endocardial and epicardial layers. Perfusion defects were more often detected in hypertrophied segments (64%). Among the 660 segments with normal wall thickness, 19% presented perfusion defects. Independently of wall thickness, segments with perfusion defects had a higher T1 (ß-estimate 30.28, p<0.001), extracelluar volume (ß-estimate 1.50, p<0.001) and T2 (ß-estimate 0.73, p<0.001) and had late gadolinium enhancement more frequently (odds ratio 4.16, p<0.001). Higher values of circumferential strain (lower deformation) and lower values of radial strain were found in segments with perfusion defects (ß-estimate 2.76, p<0.001; and ß-estimate -10.39, p<0.001, circumferential and radial strain, respectively). CONCLUSION: While microvascular dysfunction was more prevalent in more hypertrophied segments, it also had a major presence in segments without hypertrophy. In this segmental analysis, we found an association between the presence of ischemia and tissue abnormalities, replacement fibrosis as well as impaired strain, independently of the segmental wall thickness.

Index of microcirculatory resistance in the assessment of coronary microvascular dysfunction in hypertrophic cardiomyopathy.

INTRODUCTION AND OBJECTIVES: Coronary microvascular dysfunction (CMD) is one of the most important pathophysiological features in hypertrophic cardiomyopathy (HCM). The index of microcirculatory resistance (IMR) is an invasive method to assess the coronary microcirculation. The aim was to assess CMD in patients with HCM by IMR. METHODS: Adult patients with HCM without epicardial coronary artery disease underwent cardiac catheterization for the assessment of CMD by IMR (normal cut-off value ≤22.0) and coronary flow reserve (CFR) (normal cut-off value ≥2). Cardiovascular magnetic resonance (CMR) was performed to assess the ischemic burden by perfusion imaging during regadenoson-induced hyperemia, and the extent of myocardial fibrosis was assessed by late gadolinium enhancement (LGE), native T1 mapping and extracellular volume (ECV). RESULTS: Fourteen patients were enrolled with a mean age of 62.8±6.2years, 8 (57.1%) males, of whom 9 (64.3%) had obstructive HCM. Using IMR, CMD was detected in 4 (29%) patients. Among four patients with an IMR>22.0, all had non-obstructive HCM and two had angina. CFR<2 was reported in eight patients (57%). Concordance between IMR and CFR (both normal or both abnormal) was verified in 6 patients (43%). Among four patients with IMR>22.0, perfusion defects were found in two of the three patients who underwent stress CMR. Increased ECV (>28%) was documented in two of the patients with IMR>22 and in three of the patients with IMR≤22.0. LGE was >15% in 2 of the patients with IMR>22 and in 4 with IMR≤22.0. CONCLUSIONS: IMR assessment in HCM is feasible and safe. Patients with abnormal IMR seemed to have more significant tissue abnormalities on CMR.

Efectos del entrenamiento en marcos relacionales de condicionalidad sobre el responder relacional deíctico / Effects of Training in Conditional Relational Framing on the Deictic Relational Responding

Resumen Desde la Teoría de los Marcos Relacionales, la toma de perspectiva se concibe como un patrón de responder relacional arbitrariamente aplicable bajo control de claves contextuales deícticas personales, espaciales y temporales. Además, se asume necesaria la capacidad para responder relacionalmente bajo el control de claves contextuales condicionales. Sin embargo, no se ha reportado evidencia empírica que permita identificar la relación existente entre los marcos de condicionalidad y la precisión en el responder relacional deíctico. El objetivo del estudio fue analizar si el entrenamiento en marco de condicionalidad podría facilitar el desempeño sobre el responder deíctico. Participaron cuatro niños con desarrollo normalizado que fueron divididos en dos condiciones experimentales (C1 y C2). Los participantes de ambas condiciones se expusieron a un protocolo de evaluación y entrenamiento en marcos deícticos. A su vez, solo los participantes de la C2 se expusieron a una fase de evaluación y entrenamiento en marcos de condicionalidad previo al entrenamiento en marcos deícticos. Los resultados mostraron que todos los participantes exhibieron mejoras en sus ejecuciones post-test en las relaciones deícticas y que los participantes de C2 obtuvieron mejores resultados con respecto a su pre-test en los niveles de mayor complejidad deíctica tras el entrenamiento en marcos condicionales. Se discute la necesidad de protocolos de toma de perspectiva más naturalistas que posibiliten indagar en cómo se desarrollan los términos relacionales y se abstrae la función de las claves contextuales que permiten interpretar, atribuir y predecir el comportamiento de otro.

Abstract According to Relational Frame Theory, perspective taking is conceived as an arbitrarily applicable relational pattern of relational responding under the control of personal, spatial, and temporal deictic contextual cues. Furthermore, the ability to respond relationally under the control of conditional contextual cues is assumed to be necessary. However, no empirical evidence has been reported to identify the relationship between conditionality frames and accuracy in deictic relational responding. The study aimed to analyze whether training in conditionality frames could facilitate performance on deictic responding. Four children with normalized development participated and were divided into two experimental conditions (C1 and C2). Participants in both conditions were exposed to an evaluation protocol and training on deictic frames. In turn, only C2 participants were exposed to an evaluation and training phase in conditionality frames before the training in deictic frames. Results showed that all the participants exhibited improvements in their post-test performances on deictic relations and that the C2 participants performed better with respect to their pre-test on the levels of greater deictic complexity after training in conditional frames. We discuss the need for more naturalistic perspective-taking protocols that allow us to investigate how relational terms are developed and abstract the role of contextual cues that allow us to interpret, attribute, and predict another's behavior.

Exercise stress echocardiography: Where are we now?

Exercise stress echocardiography (ESE) is a widely used diagnostic test in cardiology departments. ESE is mainly used to study patients with coronary artery disease; however, it has increasingly been used in other clinical scenarios including valve pathology, congenital heart disease, hypertrophic and dilated cardiomyopathies, athlete evaluations, diastolic function evaluation, and pulmonary circulation study. In our laboratories, we use an established methodology in which cardiac function is evaluated while exercising on a treadmill. After completing the exercise regimen, patients remain in a standing position or lie down on the left lateral decubitus, depending on the clinical questions to be answered for further evaluation. This method increases the quality and quantity of information obtained. Here, we present the various methods of exercise stress echocardiography and our experience in many clinical arenas in detail. We also present alternatives to ESE that may be used and their advantages and disadvantages. We review recent advances in ESE and future directions for this established method in the study of cardiac patients and underline the advantage of using a diagnostic tool that is radiation-free.

Transaxillary Approach for Surgical Repair of Simple Congenital Cardiac Lesions: Pitfalls, and Complications.

BACKGROUND: In the treatment of simple congenital cardiac lesions, percutaneous and cosmetic surgical approaches have steadily gained prominence. Surgically, right vertical axillary approach is sparsely used despite superior cosmesis and less pain and blood product usage. Knowledge of potential pitfalls could lead to its more widespread acceptance. METHODS: We retrospectively analyzed perioperative outcomes of 104 consecutive patients who underwent surgery by this technique between mid-2016 and December 2019, including ostium secundum (67), sinus venosus (34), coronary sinus (1), and ostium primum (1) atrial septal defects and hemianomalous pulmonary venous connection (1). Perioperative variables, surgical times, complications, and follow-up data were analyzed. RESULTS: Patient weight ranged from 6.8 to 41 kg. Incision length ranged from 4 to 6 cm. There was no mortality. All cannulation was central. Difficulty in cannulation (inferior vena cava) was seen in two patients. Morbidity included pneumothorax in 2 (1.9%) patients and subcutaneous emphysema necessitating prolonged intercostal drain retention in 20 (19.2%) patients. Surgical time increased linearly (r = 0.567; P < .001) with increasing patient weight but cardiopulmonary bypass (CPB) time remained unaffected. No chest deformities or paresthesia were noted on follow-up. Scar size decreased in some patients. CONCLUSIONS: Right vertical axillary approach can be safely employed to treat simple congenital cardiac lesions with adequate awareness of potential pitfalls. Increasing patient weight increases the surgical time but does not affect CPB times. Incidence of pneumothorax and subcutaneous emphysema is similar to other thoracotomy approaches. It is cosmetically superior.

Myocardial work is associated with significant left ventricular myocardial fibrosis in patients with hypertrophic cardiomyopathy.

Late gadolinium enhancement on cardiac magnetic resonance adds prognostic information in patients with hypertrophic cardiomyopathy. Whether Myocardial work, a new parameter on transthoracic echocardiographic, can be associated with significant fibrosis in hypertrophic cardiomyopathy patients is unknown. In a single-centre prospective evaluation of hypertrophic cardiomyopathy patients in whom transthoracic echocardiographic and cardiac magnetic resonance were performed, Myocardial work and related indices were calculated from global longitudinal strain and from estimated left ventricular pressure curves. The extent of late gadolinium enhancement was quantitatively assessed. Late gadolinium enhancement ≥ 15% was chosen to define significant fibrosis. Logistic regression analysis was used to find the variables associated with late gadolinium enhancement ≥ 15% and cut-off values were determined. Among the forty-six patients analysed mean age was 56 ± 15 years, 28 (61%) were male patients and the mean left ventricular ejection fraction by transthoracic echocardiographic was 67 ± 8%. Global constructive work and global work index were significantly related to late gadolinium enhancement ≥ 15%, while global longitudinal strain nearly reached statistical significance. A cut-off ≤ 1550 mmHg% of global constructive work was associated with significant fibrosis with a sensitivity of 91% and a specificity of 84%, while the best cut-off for global longitudinal strain (> - 15%) had a sensitivity of 67% and a specificity of 76%. In our study cohort, global constructive work was associated with significant left ventricular myocardial fibrosis in cardiac magnetic resonance, suggesting its utility in patients who may not be able to have a cardiac magnetic resonance study.

The Impact of Ischemia Assessed by Magnetic Resonance on Functional, Arrhythmic, and Imaging Features of Hypertrophic Cardiomyopathy.

Aims: The aim of the study is to investigate the association between the degree of ischemia due to coronary microvascular dysfunction (CMD) and the left ventricular (LV) tissue characteristics, systolic performance, and clinical manifestations in hypertrophic cardiomyopathy (HCM). Methods and Results: This prospective study enrolled 75 patients with HCM without obstructive epicardial coronary artery disease. Each patient underwent cardiovascular magnetic resonance (CMR) including parametric mapping, perfusion imaging during regadenoson-induced hyperemia, late gadolinium enhancement (LGE) and three-dimensional longitudinal, circumferential, and radial strains analysis. Electrocardiogram, 24-h Holter recording, and cardiopulmonary exercise testing (CPET) were performed to assess arrhythmias and functional capacity. In total, 47 (63%) patients were men with the mean age of 54.6 (14.8) years, 51 (68%) patients had non-obstructive HCM, maximum wall thickness (MWT) was 20.2 (4.6) mm, LV ejection fraction (LVEF) was 71.6 (8.3%), and ischemic burden was 22.5 (16.9%) of LV. Greater MWT was associated with the severity of ischemia (ß-estimate:1.353, 95% CI:0.182; 2.523, p = 0.024). Ischemic burden was strongly associated with higher values of native T1 (ß-estimate:9.018, 95% CI:4.721; 13.315, p < 0.001). The association between ischemia and LGE was significant in following subgroup analyses: MWT 15-20 mm (ß-estimate:1.941, 95% CI:0.738; 3.143, p = 0.002), non-obstructive HCM (ß-estimate:1.471, 95% CI:0.258; 2.683, p = 0.019), women (ß-estimate:1.957, 95% CI:0.423; 3.492, p = 0.015) and age <40 years (ß-estimate:4.874, 95% CI:1.155; 8.594, p = 0.016). Ischemia in ≥21% of LV was associated with LGE >15% (AUC 0.766, sensitivity 0.724, specificity 0.659). Ischemia was also associated with atrial fibrillation or flutter (AF/AFL) (OR-estimate:1.481, 95% CI:1.020; 2.152, p = 0.039), but no association was seen for non-sustained ventricular tachycardia. Ischemia was associated with shorter time to anaerobic threshold (ß-estimate: -0.442, 95% CI: -0.860; -0.023, p = 0.039). Conclusion: In HCM, ischemia associates with morphological markers of severity of disease, fibrosis, arrhythmia, and functional capacity.

Tricuspid Prosthesis Malfunction Unmasked By Exercise Stress Echocardiography.

Exercise echocardiography is used mainly in the study of patients with coronary artery disease, however the technique is increasingly used in the study of other pathologies. We present the first case of use of exercise stress echocardiography for clinical decision in one patient with biological prostheses in tricuspid position. The clinical exam, the echocardiogram, the cardiac MRI, the NT proBNP were normal and the patient has been considered to have no indication for surgery. The patient was only presented and accepted for surgery after the results of exercise stress echocardiography.

Análisis del concepto de abstracción y su uso en referencia a las relaciones conductuales / An analysis of the concept of abstraction and its use about behavioral relations

Resumen El concepto de abstracción ha sido difundido en la literatura conceptual y experimental en el análisis de la conducta desde inicios del siglo XX. Su uso en las aproximaciones derivadas de la teoría del condicionamiento, predominantemente ha sido permeado por categorías de orden operacional, lo cual ha permitido que se considere de forma equivalente o análoga a los conceptos de categorización y formación de conceptos, y que se formulen taxonomías de niveles de abstracción con base en criterios morfológicos. En el presente escrito, se describen las características de dichos usos en la tradición del análisis de la conducta, se identifican algunas insuficiencias conceptuales en torno a su definición con base en categorías operacionales y morfológicas, y se propone como alternativa una definición del comportamiento abstracto y una taxonomía de niveles de complejidad de este comportamiento desde una perspectiva interconductual.

Abstract The use of the concept of abstraction has been disseminated within the conditioning theory, predominantly permeated by operational categories, which has allowed it to be considered equivalent to the concepts of categorization and concept formation. Consequently, the taxonomies of levels of abstraction are formulated based on morphological criteria. In the present paper, the characteristics of these uses are described, some shortcomings are identified around their definition based on operational and morphological categories, and an alternative definition of abstract behavior and a taxonomy of complexity levels from a perspective interbehavioral is proposed.

Female Gender is not a Risk Factor for Early Mortality after Coronary Artery Bypass Grafting.

Background: The female gender is considered as a risk factor for morbidity and mortality after coronary artery bypass grafting (CABG). Aim: In this analysis, we assessed the impact of female gender on early outcome after CABG. Study Design: This is a retrospective analysis of data from our center situated in South India. Statistical Analysis: Patients were categorized according to gender and potential differences in pre-operative and post-operative factors were explored. Significant risk factors were then built in a multivariate model to account for differences in predicting gender influence on surgical outcome. Methods: 773 consecutive patients underwent first time CABG between January 2015 and December 2016. 96.77% of cases were performed using off-pump technique. 132 (17.07%) patients were females. These patients formed the study group. Results: The in-house/ 30-day mortality in females was similar to that of males (3.03% vs. 3.12%, p value 0.957). Mediastinitis developed more commonly in females (5.35% vs. 1.30%; p value 0.004) compared to males. There were more re-admissions to hospital for female patients (21.37% in females vs. 10.14% in males, p value <0.001). In multivariate analysis using logistic regression; there was a significant association between age (OR 1.08), chronic obstructive airway disease (OR 4.315), and use of therapeutic antibiotics (OR 6.299), IABP usage (OR 11.18) and renal failure requiring dialysis (OR 28.939) with mortality. Conclusions: Early mortality in females was similar to that of males. Females were associated with higher rate of wound infection and readmission to hospital.

Modified technique for uncommon coarctation of the aorta with arch hypoplasia.

A true presubclavian coarctation of the aorta with arch hypoplasia without major intracardiac anomaly can result in a surgical dilemma. Theoretically, one can avoid repair through median sternotomy using selective cerebral perfusion and its sequelae since no major intracardiac repair is needed. Repair through thoracotomy is technically challenging if arch reconstruction is required and precise surgical planning is required to avoid spinal hypoperfusion and to maintain cerebral perfusion. Moreover, inadequate repair often has resulted in hypoplastic aortic arch or residual coarctation on follow-up requiring future intervention. We have employed a modified surgical repair through thoracotomy avoiding cardiopulmonary bypass to address presubclavian coarctation of the aorta with diffuse arch hypoplasia with theoretically less chance for future stenosis.

In silico and in vitro analysis of boAP3d1 protein interaction with bovine leukaemia virus gp51.

The envelope glycoprotein 51 (gp51) is essential for bovine leukaemia virus (BLV) entry to bovine B-lymphocytes. Although the bovine adaptor protein 3 complex subunit delta-1 (boAP3D1) has been proposed as the potential receptor, the specific ligand-receptor interaction has not yet been completely defined and boAP3D1 receptor and gp51 3D structures have not been determined. This study was thus aimed at a functional annotation of boAP3D1 cellular adaptor protein and BLV gp51 and, proposing a reliable model for gp51-AP3D1 interaction using bioinformatics tools. The boAP3D1 receptor interaction patterns were calculated based on models of boAP3D1 receptor and gp51 complexes' 3D structures, which were constructed using homology techniques and data-driven docking strategy. The results showed that the participation of 6 key amino acids (aa) on gp51 (Asn170, Trp127, His115, Ala97, Ser98 and Glu128) and 4 aa on AP3D1 (Lys925, Asp807, Asp695 and Arg800) was highly probable in the interaction between gp51 and BLVR domains. Three gp51 recombinant peptides were expressed and purified to validate these results: the complete domain (rgp51), the N-terminal portion (rNgp51) and the C-terminal fragment (rCgp51); and binding assays to Madin-Darby bovine kidney (MDBK) cells were then carried out with each recombinant. It was found that rNgp51 preferentially bound to MDBK cells, suggesting this domain's functional role during invasion. The rNgp51-MDBK cell interaction was sensitive to trypsin (98% reduction) and chymotrypsin treatment (80% reduction). These results highlighted that the N-terminal portion of gp51 interacted in vitro with the AP3D1 receptor and provides a plausible in silico interaction model.

Effects of the Functional Content of Instructions on Second-Order Matching-to-Sample Performance / Efeitos do conteúdo funcional da instrução sobre o desempenho em igualação à amostra de segunda ordem / Efectos del contenido funcional de la instrucción sobre el desempeño en igualación a la muestra de segundo orden

Abstract The effect of the functional content of instructions on the acquisition, transfer and description of performance in a second order matching-to-sample task was evaluated. Twenty undergraduate students were assigned to one of four experimental groups: (a) procedural instruction at the start of the task (PStart); (b) procedural instruction in each trial (PTrial); (c) instruction referring to instances in each trial (ITrial); and (d) instruction referring to relation in each trial (RTrial). The proportion of correct attempts was analyzed, and was found to be higher in the ITrial and RTrial groups for the training phase, and for the PStart, PTrial and RTrial groups in the extra-instance and extra-modal transfer test, as well as for the ITrial group in the extra-relational test; the larger number of accurate performance descriptions was observed in the RTrial group. These results show that abstract stimulus control can be presented either by way of transfer of functions throughout instructions, or by differentiation of positive and negative cases of the contingencies, which is enhanced by the concurrent presence of the instruction and the stimulus array.

Resumo Neste estudo, avaliou-se o efeito do conteúdo funcional da instrução sobre a aquisição, transferência e descrição da execução numa tarefa de igualação à amostra de segunda ordem. Foram designados vinte estudantes de psicologia a um de quatro grupos experimentais: (a) instrução procedimental ao início da tarefa (PInício); (b) instrução procedimental em cada ensaio (PEnsaio); (c) instrução referida a instâncias em cada ensaio (IEnsaio), e (d) instrução referida à relação em cada ensaio (REnsaio). Analisou-se a proporção de acertos, a qual foi superior nos grupos IEnsaio e REnsaio na fase de treinamento, para os grupos PInício, PEnsaio e REnsaio em testes de transferência extrainstância e extramodal, e para o grupo IEnsaio em testes de transferência extrarrelacional; a maior quantidade de descrições adequadas de execução se apresentou no grupo REnsaio. Esses resultados mostram que o controle abstrato do estímulo pode ser apresentado tanto por transferência de função por meio de instruções quanto por diferenciação de casos positivos e negativos das contingências, o que se vê potencializado pela presença simultânea da instrução e do acordo estimulativo.

Resumen En el presente estudio se evaluó el efecto del contenido funcional de la instrucción sobre la adquisición, transferencia y descripción de la ejecución en una tarea de igualación a la muestra de segundo orden. Se asignaron veinte estudiantes de psicología a uno de cuatro grupos experimentales: (a) instrucción procedimental al inicio de la tarea (PInicio); (b) instrucción procedimental en cada ensayo (PEnsayo); (c) instrucción referida a instancias en cada ensayo (IEnsayo); y (d) instrucción referida a relación en cada ensayo (REnsayo). Se analizó la proporción de aciertos, la cual fue superior en los grupos IEnsayo y REnsayo en la fase de entrenamiento, para los grupos PInicio, PEnsayo y REnsayo en pruebas de transferencia extrainstancia y extramodal, y para el grupo IEnsayo en pruebas de transferencia extrarelacional; la mayor cantidad de descripciones adecuadas de ejecución se presentó en el grupo REnsayo. Estos resultados muestran que el control abstracto del estímulo se puede presentar tanto por transferencia de función a través de instrucciones como por diferenciación de casos positivos y negativos de las contingencias, lo cual se ve potenciado por la presencia concurrente de la instrucción y el arreglo estimulativo.

Easy and fast method for expression and native extraction of Plasmodium vivax Duffy binding protein fragments.

BACKGROUND: The Plasmodium vivax Duffy binding protein (PvDBP) has been the most studied ligand binding human reticulocytes to date. This molecule has a cysteine-rich domain in region II (RII) which has been used as control for evaluating the target cell binding activity of several parasite molecules. However, obtaining rPvDBP-RII in a soluble form using the Escherichia coli expression system usually requires laborious and time-consuming steps for recovering the molecule's structure and function, considering it is extracted from inclusion bodies. The present study describes an easy and fast method for expressing and obtaining several PvDBP fragments which should prove ideal for use in protein-cell interaction assays. RESULTS: Two PvDBP encoding regions (rii and riii/v) were cloned in pEXP5-CT vector and expressed in E. coli and extracted from the soluble fraction (rPvDBP-RIIS and rPvDBP-RIII/VS) using a simple freezing/thawing protocol. After the purification, dichroism analysis enabled verifying high rPvDBP-RIIS and rPvDBP-RIII/VS secondary structure α-helix content, which was lowered when molecules were extracted from inclusion bodies (rPvDBP-RIIIB and rPvDBP-RIII/VIB) using a denaturing step. Interestingly, rPvDBP-RIIS, but not rPvDBP-RIIIB, bound to human reticulocytes, while rPvDBP-RIII/VS and rPvDBP-RIII/VIB bound to such cells in a similar way to negative control (cells incubated without recombinant proteins). CONCLUSIONS: This research has shown for the first time how rPvDBP-RII can be expressed and obtained in soluble form using the E. coli system and avoiding the denaturation and refolding steps commonly used. The results highlight the usefulness of the rPvDBP-RIII/VS fragment as a non-binding control for protein-cell target interaction assays. The soluble extraction protocol described is a good alternative to obtain fully functional P. vivax proteins in a fast and easy way, which will surely prove useful to laboratories working in studying this parasite's biology.

Funciones ejecutivas, rasgos de personalidad e impulsividad en condenados por acceso carnal violento / Executive functions, personality traits and impulse-control in convicted of violent-carnal access

Resumen Se evaluaron las funciones ejecutivas, los rasgos de personalidad y la impulsividad en 29 hombres condenados por acceso carnal violento y recluidos en la cárcel Modelo Bogotá-Colombia, mediante un cuestionario sociodemográfico, la Batería Neuropsicológica de Funciones Ejecutivas y Lóbulos Frontales (banfe), la Escala de Impulsividad de Barratt (bis 11) y el Cuestionario Exploratorio de Personalidad (ceper iii), con el fin de identificar relaciones entre sus puntuaciones. Los resultados evidencian que el 41,4 % de los participantes mostró puntuaciones diagnósticas en al menos un factor de impulsividad o de funciones ejecutivas. El 79,3 % de los participantes evidenció al menos un rasgo de personalidad, siendo los del tipo obsesivo-compulsivo, pasivo-agresivo y dependiente, los de mayor frecuencia. Se identificaron algunas correlaciones entre los factores de impulsividad, los rasgos de personalidad y las funciones ejecutivas. Estos hallazgos se discuten en términos de la relación entre los constructos evaluados, la agresión sexual y sus implicaciones sobre el tratamiento penitenciario.

Abstract Executive-functions, personality traits and impulsivity were evaluated in 29 men convicted of violent-carnal access in the Modelo Jail (Bogota-Colombia), through a sociodemographic questionnaire, the Neuropsychological Battery for Executive Functions and Frontal Lobes (banfe), the Barratt Impulsivity Scale (bis 11) and the Personality Exploratory Questionnaire (ceper III), in order to identify relationships between their scores. The results show that 41,4 % of the participants showed diagnostic scores in at least one factor of impulsivity or executive functions. At least one personality trait was observed in 79,3 % of the participants; obsessive-compulsive, passive-aggressive and dependent traits were those with highest frequency. Some correlations were identified between impulsivity factors, personality traits and executive functions. These findings are discussed in terms of the relationship between the constructs evaluated, sexual assault and their implications on the treatment of prisioners.