Chronic exercise impairs nitric oxide pathway in rabbit carotid and femoral arteries.

KEY POINTS: Some of the beneficial effects of exercise in preventing vascular related diseases are mediated by the enhancement of endothelial function where the role of nitric oxide (NO) is well documented, although the relevance of calcium activated potassium channels is not fully understood. The impact of oxidative stress induced by training on endothelial function remains to be clarified. By evaluating different endothelial vasodilator pathways on two vascular beds in a rabbit model of chronic exercise, we found a decreased NO bioavailability and endothelial nitric oxide synthase expression in both carotid and femoral arteries. Physical training induced carotid endothelial dysfunction as a result of an increase in oxidative stress and a reduction in superoxide dismutase expression. In the femoral artery, the lower production of NO was counteracted by an increased participation of large conductance calcium activated potassium channels, preventing endothelial dysfunction. ABSTRACT: The present study aimed to evaluate the effects of chronic exercise on vasodilator response in two different arteries. Rings of carotid and femoral arteries from control and trained rabbits were suspended in organ baths for isometric recording of tension. Endothelial nitric oxide synthase (eNOS), Cu/Zn and Mn-superoxide dismutase (SOD), and large conductance calcium activated potassium (BKCa) channel protein expression were measured by western blotting. In the carotid artery, training reduced the relaxation to ACh (10-9 to 3 × 10-6  m) that was reversed by N-acetylcysteine (10-3  m). l-NAME (10-4  m) reduced the relaxation to ACh in both groups, although the effect was lower in the trained group (in mean ± SEM, 39 ± 2% vs. 28 ± 3%). Physical training did not modify the relaxation to ACh in femoral arteries, although the response to l-NAME was lower in the trained group (in mean ± SEM, 41 ± 5% vs. 17 ± 2%). Charybdotoxin (10-7  m) plus apamin (10-6  m) further reduced the maximal relaxation to ACh only in the trained group. The remaining relaxation in both carotid and femoral arteries was abolished by KCl (2 × 10-2  m) and BaCl2 (3 × 10-6  m) plus ouabain (10-4  m) in both groups. Physical training decreased eNOS expression in both carotid and femoral arteries and Cu/Zn and Mn-SOD expression only in the carotid artery. BKCa channels were overexpressed in the trained group in the femoral artery. In conclusion, chronic exercise induces endothelial dysfunction in the carotid artery as a result of oxidative stress. In the femoral artery, it modifies the vasodilator pathways, enhancing the participation of BKCa channels, thus compensating for the impairment of NO-mediated vasodilatation.

Effects of the Inhibition of Late Sodium Current by GS967 on Stretch-Induced Changes in Cardiac Electrophysiology.

PURPOSE: Mechanical stretch increases sodium and calcium entry into myocytes and activates the late sodium current. GS967, a triazolopyridine derivative, is a sodium channel blocker with preferential effects on the late sodium current. The present study evaluates whether GS967 inhibits or modulates the arrhythmogenic electrophysiological effects of myocardial stretch. METHODS: Atrial and ventricular refractoriness and ventricular fibrillation modifications induced by acute stretch were studied in Langendorff-perfused rabbit hearts (n = 28) using epicardial multiple electrodes and high-resolution mapping techniques under control conditions and during the perfusion of GS967 at different concentrations (0.03, 0.1, and 0.3 µM). RESULTS: On comparing ventricular refractoriness, conduction velocity and wavelength obtained before stretch had no significant changes under each GS967 concentration while atrial refractoriness increased under GS967 0.3 µM. Under GS967, the stretch-induced changes were attenuated, and no significant differences were observed between before and during stretch. GS967 0.3 µM diminished the normal stretch-induced changes resulting in longer (less shortened) atrial refractoriness (138 ± 26 ms vs 95 ± 9 ms; p < 0.01), ventricular refractoriness (155 ± 18 ms vs 124 ± 16 ms; p < 0.01) and increments in spectral concentration (23 ± 5% vs 17 ± 2%; p < 0.01), the fifth percentile of ventricular activation intervals (46 ± 8 ms vs 31 ± 3 ms; p < 0.05), and wavelength of ventricular fibrillation (2.5 ±0.5 cm vs 1.7 ± 0.3 cm; p < 0.05) during stretch. The stretch-induced increments in dominant frequency during ventricular fibrillation (control = 38%, 0.03 µM = 33%, 0.1 µM = 33%, 0.3 µM = 14%; p < 0.01) and the stretch-induced increments in arrhythmia complexity index (control = 62%, 0.03µM = 41%, 0.1 µM = 32%, 0.3 µM = 16%; p < 0.05) progressively decreased on increasing the GS967 concentration. CONCLUSIONS: GS967 attenuates stretch-induced changes in cardiac electrophysiology.

Effects of JTV-519 on stretch-induced manifestations of mechanoelectric feedback.

JTV-519 is a 1,4-benzothiazepine derivative with multichannel effects that inhibits Ca2+ release from the sarcoplasmic reticulum and stabilizes the closed state of the ryanodine receptor, preventing myocardial damage and the induction of arrhythmias during Ca2+ overload. Mechanical stretch increases cellular Na+ inflow, activates the reverse mode of the Na+ /Ca2+ exchanger, and modifies Ca2+ handling and myocardial electrophysiology, favoring arrhythmogenesis. This study aims to determine whether JTV-519 modifies the stretch-induced manifestations of mechanoelectric feedback. The ventricular fibrillation (VF) modifications induced by acute stretch were studied in Langendorff-perfused rabbit hearts using epicardial multiple electrodes under control conditions (n=9) or during JTV-519 perfusion: 0.1 µmol/L (n=9) and 1 µmol/L (n=9). Spectral and mapping techniques were used to establish the baseline, stretch and post-stretch VF characteristics. JTV-519 slowed baseline VF and decreased activation complexity. These effects were dose-dependent (baseline VF dominant frequency: control=13.9±2.2 Hz; JTV 0.1 µmol/L=11.1±1.1 Hz, P<.01; JTV 1 µmol/L=6.6±1.1 Hz, P<.0001). The stretch-induced acceleration of VF (control=38.8%) was significantly reduced by JTV-519 0.1 µmol/L (19.8%) and abolished by JTV 1 µmol/L (-1.5%). During stretch, the VF activation complexity index was reduced in both JTV-519 series (control=1.60±0.15; JTV 0.1 µmol/L=1.13±0.3, P<.0001; JTV 1 µmol/L=0.57±0.21, P<.0001), and was independently related to VF dominant frequency (R=.82; P<.0001). The fifth percentile of the VF activation intervals, conduction velocity and wavelength entered the multiple linear regression model using dominant frequency as the dependent variable (R=-.84; P<.0001). In conclusion, JTV-519 slowed and simplified the baseline VF activation patterns and abolished the stretch-induced manifestations of mechanoelectric feedback.

Ranolazine Attenuates the Electrophysiological Effects of Myocardial Stretch in Langendorff-Perfused Rabbit Hearts.

PURPOSE: Mechanical stretch is an arrhythmogenic factor found in situations of cardiac overload or dyssynchronic contraction. Ranolazine is an antianginal agent that inhibits the late Na (+) current and has been shown to exert a protective effect against arrhythmias. The present study aims to determine whether ranolazine modifies the electrophysiological responses induced by acute mechanical stretch. METHODS: The ventricular fibrillation modifications induced by acute stretch were studied in Langendorff-perfused rabbit hearts using epicardial multiple electrodes under control conditions (n = 9) or during perfusion of the late Na(+) current blocker ranolazine 5 µM (n = 9). Spectral and mapping techniques were used to establish the ventricular fibrillation dominant frequency, the spectral concentration and the complexity of myocardial activation in three situations: baseline, stretch and post-stretch. RESULTS: Ranolazine attenuated the increase in ventricular fibrillation dominant frequency produced by stretch (23.0 vs 40.4 %) (control: baseline =13.6 ± 2.6 Hz, stretch = 19.1 ± 3.1 Hz, p < 0.0001; ranolazine: baseline = 1.4 ± 1.8 Hz, stretch =14.0 ± 2.4 Hz, p < 0.05 vs baseline, p < 0.001 vs control). During stretch, ventricular fibrillation was less complex in the ranolazine than in the control series, as evaluated by the lesser percentage of complex maps and the greater spectral concentration of ventricular fibrillation. These changes were associated to an increase in the fifth percentile of VV intervals during ventricular fibrillation (50 ± 8 vs 38 ± 5 ms, p < .01) and in the wavelength of the activation (2.4 ± 0.3 vs 1.9 ± 0.2 cm, p < 0.001) under ranolazine. CONCLUSIONS: The late inward Na(+) current inhibitor ranolazine attenuates the electrophysiological effects responsible for the acceleration and increase in complexity of ventricular fibrillation produced by myocardial stretch.

Development and Long-Term Follow-Up of an Experimental Model of Myocardial Infarction in Rabbits.

A chronic model of acute myocardial infarction was developed to study the mechanisms involved in adverse postinfarction ventricular remodeling. In an acute myocardial infarction (AMI), the left circumflex coronary artery of New Zealand White rabbits (n = 9) was occluded by ligature for 1 h, followed by reperfusion. A specific care protocol was applied before, during, and after the intervention, and the results were compared with those of a sham operated group (n = 7). After 5 weeks, programmed stimulation and high-resolution mapping were performed on isolated and perfused hearts using the Langendorff technique. The infarct size determined by 2,3,5-triphenyltetrazolium chloride inside of the area at risk (thioflavin-S) was then determined. The area at risk was similar in both groups (54.33% (experimental infarct group) vs. 58.59% (sham group), ns). The infarct size was 73.16% as a percentage of the risk area. The experimental infarct group had a higher inducibility of ventricular arrhythmias (100% vs. 43% in the sham group, p = 0.009). A reproducible chronic experimental model of myocardial infarction is presented in which the extent and characteristics of the lesions enable the study of the vulnerability to develop ventricular arrhythmias because of the remodeling process that occurs during cardiac tissue repair.

Effect of chronic exercise on myocardial electrophysiological heterogeneity and stability. Role of intrinsic cholinergic neurons: A study in the isolated rabbit heart.

A study has been made of the effect of chronic exercise on myocardial electrophysiological heterogeneity and stability, as well as of the role of cholinergic neurons in these changes. Determinations in hearts from untrained and trained rabbits on a treadmill were performed. The hearts were isolated and perfused. A pacing electrode and a recording multielectrode were located in the left ventricle. The parameters determined during induced VF, before and after atropine (1µM), were: fibrillatory cycle length (VV), ventricular functional refractory period (FRPVF), normalized energy (NE) of the fibrillatory signal and its coefficient of variation (CV), and electrical ventricular activation complexity, as an approach to myocardial heterogeneity and stability. The VV interval was longer in the trained group than in the control group both prior to atropine (78±10 vs. 68±10 ms) and after atropine (76±8 vs. 67±10 ms). Likewise, FRPVF was longer in the trained group than in the control group both prior to and after atropine (53±8 vs. 42±7 ms and 50±6 vs. 40±6 ms, respectively), and atropine did not modify FRPVF. The CV of FRPVF was lower in the trained group than in the control group prior to atropine (12.5±1.5% vs. 15.1±3.8%) and, decreased after atropine (15.1±3.8% vs. 12.2±2.4%) in the control group. The trained group showed higher NE values before (0.40±0.04 vs. 0.36±0.05) and after atropine (0.37±0.04 vs. 0.34±0.06; p = 0.08). Training decreased the CV of NE both before (23.3±2% vs. 25.2±4%; p = 0.08) and after parasympathetic blockade (22.6±1% vs. 26.1±5%). Cholinergic blockade did not modify these parameters within the control and trained groups. Activation complexity was lower in the trained than in the control animals before atropine (34±8 vs. 41±5), and increased after atropine in the control group (41±5 vs. 48±9, respectively). Thus, training decreases the intrinsic heterogeneity of the myocardium, increases electrophysiological stability, and prevents some modifications due to muscarinic block.

Effects of S-Nitrosoglutathione on Electrophysiological Manifestations of Mechanoelectric Feedback.

Electromechanical coupling studies have described the intervention of nitric oxide and S-nitrosylation processes in Ca2+ release induced by stretch, with heterogeneous findings. On the other hand, ion channel function activated by stretch is influenced by nitric oxide, and concentration-dependent biphasic effects upon several cellular functions have been described. The present study uses isolated and perfused rabbit hearts to investigate the changes in mechanoelectric feedback produced by two different concentrations of the nitric oxide carrier S-nitrosoglutathione. Epicardial multielectrodes were used to record myocardial activation at baseline and during and after left ventricular free wall stretch using an intraventricular device. Three experimental series were studied: (a) control (n = 10); (b) S-nitrosoglutathione 10 µM (n = 11); and (c) S-nitrosoglutathione 50 µM (n = 11). The changes in ventricular fibrillation (VF) pattern induced by stretch were analyzed and compared. S-nitrosoglutathione 10 µM did not modify VF at baseline, but attenuated acceleration of the arrhythmia (15.6 ± 1.7 vs. 21.3 ± 3.8 Hz; p < 0.0001) and reduction of percentile 5 of the activation intervals (42 ± 3 vs. 38 ± 4 ms; p < 0.05) induced by stretch. In contrast, at baseline using the 50 µM concentration, percentile 5 was shortened (38 ± 6 vs. 52 ± 10 ms; p < 0.005) and the complexity index increased (1.77 ± 0.18 vs. 1.27 ± 0.13; p < 0.0001). The greatest complexity indices (1.84 ± 0.17; p < 0.05) were obtained during stretch in this series. S-nitrosoglutathione 10 µM attenuates the effects of mechanoelectric feedback, while at a concentration of 50 µM the drug alters the baseline VF pattern and accentuates the increase in complexity of the arrhythmia induced by myocardial stretch.

Do indicators of maternal iron status reflect placental iron status at delivery?

Indicators of maternal iron (Fe) status were studied in relation to placental Fe (Pl-Fe) status. Placental (Pl) and maternal (M) venous blood samples were obtained from primiparous women (n = 38), with normal delivery at Paroissien Hospital, Argentina. Maternal hemoglobin (M Hb), soluble transferrin receptor (M sTfR) (ELISA) and serum ferritin (M S-Ft) were studied in relation to Pl-Fe, ferritin (Pl-Ft) and transferrin receptor (Pl-TfR). Pl-TfR was measured by dot blot assay, Pl-Ft and M S-Ft by immunoassay (IRMA) and Pl-Fe by atomic absorption spectrometry. Fe status indicators were, respectively, (mean +/- SD): M Hb 113 +/- 16 g/L; M S-Ft 36 +/- 42 microg/L; M sTfR 6.3 +/- 3.1 mg/L; Pl-Fe 170 +/- 56 microg/g placenta; Pl-Ft 33 +/- 18 microg/g placenta; Pl-TfR 18 +/- 18 (range 0-58) microg/g placenta. Pl-Fe, Pl-Ft and Pl-TfR did not correlate to M Hb, M S-Ft and M sTfR. Women with Pl- Fe, Pl-Ft and Pl-TfR above or below the corresponding median values did not show any statistical significant difference in M Hb, M sTfR or M S-Ft values. Pl-Ft concentration was lower in women with Hb < 110 g/L than in women with normal values: 26 +/- 13 vs. 38 +/- 20 microg/g, respectively (p = 0.021). When Pl-TfR, Pl-Ft and Pl-Fe were compared in women with M S-Ft above or below the cut-off point of 10 or 20 microg/L, no significant difference was found for Pl-TfR neither for Pl-Ft nor Pl-Fe. These results suggest that maternal indicators of Fe status, particularly M sTfR and M S-Ft, do not reflect Fe status of the placenta at delivery.

Experimental Study of the Effects of EIPA, Losartan, and BQ-123 on Electrophysiological Changes Induced by Myocardial Stretch.

INTRODUCTION AND OBJECTIVES: Mechanical response to myocardial stretch has been explained by various mechanisms, which include Na(+)/H(+) exchanger activation by autocrine-paracrine system activity. Drug-induced changes were analyzed to investigate the role of these mechanisms in the electrophysiological responses to acute myocardial stretch. METHODS: Multiple epicardial electrodes and mapping techniques were used to analyze changes in ventricular fibrillation induced by acute myocardial stretch in isolated perfused rabbit hearts. Four series were studied: control (n = 9); during perfusion with the angiotensin receptor blocker losartan (1 µM, n = 8); during perfusion with the endothelin A receptor blocker BQ-123 (0.1 µM, n = 9), and during perfusion with the Na(+)/H(+) exchanger inhibitor EIPA (5-[N-ethyl-N-isopropyl]-amiloride) (1 µM, n = 9). RESULTS: EIPA attenuated the increase in the dominant frequency of stretch-induced fibrillation (control=40.4%; losartan=36% [not significant]; BQ-123=46% [not significant]; and EIPA=22% [P<.001]). During stretch, the activation maps were less complex (P<.0001) and the spectral concentration of the arrhythmia was greater (greater regularity) in the EIPA series: control=18 (3%); EIPA = 26 (9%) (P < .02); losartan=18 (5%) (not significant); and BQ-123=18 (4%) (not significant). CONCLUSIONS: The Na(+)/H(+) exchanger inhibitor EIPA attenuated the electrophysiological effects responsible for the acceleration and increased complexity of ventricular fibrillation induced by acute myocardial stretch. The angiotensin II receptor antagonist losartan and the endothelin A receptor blocker BQ-123 did not modify these effects.

Interrelationship between bone turnover markers and dietary calcium intake in pregnant women: a longitudinal study.

This longitudinal study evaluated bone turnover and the interrelationship between changes in bone biomarkers and habitual dietary calcium intake during pregnancy in a group of women ranging widely with regard to dietary calcium intake. Thirty-nine healthy pregnant and 30 nonpregnant women were studied. Calcium, phosphorus, 1alpha,25-dihydroxyvitamin D (1,25diHOD), bone alkaline phosphatase (bALP), carboxyterminal propeptides of type I procollagen (PICP) and carboxyterminal telopeptides of type I collagen (betaCTX and ICTP) were measured in serum and calcium, and creatinine and aminoterminal telopeptide (NTX) were determined in urine. Serum calcium and phosphorus did not change but the urinary Ca/Creat ratio and 1,25diHOD increased throughout pregnancy (P < 0.001 and P < 0.0001, respectively). Serum b-ALP and PICP increased during the last two trimesters (P < 0.0001 and P < 0.001, respectively). All studied bone resorption markers increased compared to nonpregnant values throughout pregnancy. The highest increment was observed in the third trimester. The level of significance decreased as follows: betaCTX > NTX >ICTP. Serum 1,25 diHOD versus calcium intake showed a positive and significant correlation (r = 0.51, P < 0.02). A negative correlation between the absolute change in betaCTX, NTX, and b-ALP between the third and second trimester and calcium intake at the end of pregnancy was observed in pregnant women who did not cover adequately calcium intake requirements (r = -0.47, P < 0.03; r = -0.41, P < 0.05; and r = -0.43, P < 0.05, respectively). These results suggest that skeletal response to pregnancy may not be entirely independent of maternal calcium intake, especially in women with usually low calcium intake. In summary, not only hormonal changes in calcium metabolism that occur during pregnancy but also other considerations, such as low dietary calcium intake, may lead to an increment in the biological activity of the skeleton. Additional studies must be conducted to confirm our findings and to gain a better understanding of skeletal response to a low calcium intake during pregnancy.

[Usefulness of erythrocyte protoporphyrin test in the puerperium compared to the soluble transferrin receptor]. / Utilidad en el post parto de la determinación de protoporfirina eritrocitaria y su relación con el receptor soluble de transferrina.

UNLABELLED: Erythrocyte protoporphyrin (EP), serum ferritin (SF), soluble transferrin receptor (sTfR) and routine hematological laboratory tests were studied in 77 women 24 h post-partum, assisted at Paroissien Hospital (in Buenos Aires Province). Hematocrite (Hct), hemoglobin (Hb), red blood cells (RBC) and white blood cells (WBC) were determined using an electronic counter (Mega); EP by Piomelli's; SF by ELISA (IMx Ferritina, Abbott); sTfR by ELISA (Orion Diagnostica) and C-Reactive Protein (PCR-Latex, Wiener lab). All determinations were made in fasting blood samples. Statistical analysis (Receiver Operating Characteristics, ROC) were performed using Med Calc software. The soluble transferrin receptor (sTfR) was used as gold standard. RESULTS: (mean +/- SD): Hct (%) 35 +/- 5; Hb (g/l) 113 +/- 18; RBC x 103/mm3 3,893 +/- 489; MCV (fL) 90 +/- 6; WBC/mm3 9,543 +/- 2,669; EP (microg/dl RBC) 46 +/- 39; sTfR (mg/l) 4.7 +/- 2.8; SF (microg/l) 26 +/- 31; PCR (Pos/Neg) 72/5. EP did not correlate with SF but it did with sTfR (r=0.323, p=0.007). Sensitivity (Se) and specificity (Sp) of SF and EP were, respectively: 83% and 63% for a cut-off point of 25 microg SF/L; 38% and 90% for a cut-off point of 53 microg EPdl RBC. These results suggest that EP might be a useful and cheap indicator to assess maternal Fe nutritional status during the early perinatal period in hospital laboratories, allowing the detection of 16% of women presenting normal Hb values.

[Pica during pregnancy: a frequently underestimated problem]. / La pica durante el embarazo: un trastorno frecuentemente subestimado.

Pica is the compulsive intake of non-nutritive substances such as earth, clay, chalk, soap and ice. The most common forms of pica are geophagia or the intake of earth and pagophagia or the intake of ice. The description of this peculiar phenomenon dates back to the Greco-Roman civilization. Its prevalence during pregnancy is generally underestimated. Published data reveal a prevalence of between 8% and 65%. Investigations from Latin America indicate a prevalence of 23% to 44%. It is not clear yet which are the causes that predispose to pica, but they are frequently associated with anemia or iron deficiency during pregnancy. Its diagnosis, which only consists in questioning pregnant women, is generally omitted during prenatal care, probably because health professionals have no knowledge about this disorder. The identification of pica in pregnant women could contribute to the detection of a risk group where it is necessary to implement strategies as regards both the evaluation and the nutritional education.

Evaluation of the complexity of myocardial activation during ventricular fibrillation. An experimental study.

INTRODUCTION AND OBJECTIVES: An experimental model is used to analyze the characteristics of ventricular fibrillation in situations of variable complexity, establishing relationships among the data produced by different methods for analyzing the arrhythmia. METHODS: In 27 isolated rabbit heart preparations studied under the action of drugs (propranolol and KB-R7943) or physical procedures (stretching) that produce different degrees of change in the complexity of myocardial activation during ventricular fibrillation, use was made of spectral, morphological, and mapping techniques to process the recordings obtained with epicardial multielectrodes. RESULTS: The complexity of ventricular fibrillation assessed by mapping techniques was related to the dominant frequency, normalized spectral energy, signal regularity index, and their corresponding coefficients of variation, as well as the area of the regions of interest identified on the basis of these parameters. In the multivariate analysis, we used as independent variables the area of the regions of interest related to the spectral energy and the coefficient of variation of the energy (complexity index=-0.005×area of the spectral energy regions -2.234×coefficient of variation of the energy+1.578; P=.0001; r=0.68). CONCLUSIONS: The spectral and morphological indicators and, independently, those derived from the analysis of normalized energy regions of interest provide a reliable approach to the evaluation of the complexity of ventricular fibrillation as an alternative to complex mapping techniques.

Evaluación del ambiente educacional en residencias de cardiología / Assessment of Educational Environment in Cardiology Residencies

Introducción: El "ambiente educacional", producto del ambiente físico, de las relaciones interpersonales, de los factores estresantes y del sistema de reconocimientos y sanciones, entre otros, influye en la motivación de los estudiantes, en la disposición hacia el estudio y en el rendimiento académico. La evaluación del ambiente educacional se focaliza en la percepción que los estudiantes tienen del contexto más allá de lo que podría ser apreciado "objetivamente" por un observador externo. Objetivo: Presentar los resultados obtenidos de la aplicación de una versión local del cuestionario PHEEM a residentes de cardiología para explorar si la percepción de los residentes es diferente según la condición pública o privada del servicio hospitalario. Material y métodos: Se utilizó el cuestionario PHEEM (Postgraduate Hospital Educational Environment Measure), desarrollado por S. Roff, S. McAleer y A. Skinner, el cual es un instrumento específico para evaluar el ambiente educacional en el contexto hospitalario. Resultados: Respondieron 148 residentes de 31 hospitales diferentes de la Ciudad de Buenos Aires y el Conurbano Bonaerense, asistentes al Curso Bienal de Cardiología en 2012: 71 residentes de hospitales públicos, 75 de hospitales privados y 2 no identificaron la condición del hospital. Se encontraron diferencias significativas que indicarían mejores condiciones para el aprendizaje en las residencias privadas. Las diferencias se refieren a la disponibilidad de supervisión, a las instalaciones sanitarias y sala de reuniones/descanso para los médicos de guardia, a la sensación de seguridad física dentro del hospital y a la cantidad de consultas y de estudios suficientes para el aprendizaje. No se registraron discrepancias en cuanto al alto nivel de exigencia, al escaso feedback y a la falta de tiempo "protegido" para estudiar dentro del horario de trabajo semanal. Conclusión: Sería necesario evaluar residencias de otras especialidades y en otras jurisdicciones para analizar si se trata de una conclusión general o si aplica solo a la especialidad cardiología en el área metropolitana.

Introduction: The "educational environment", which is the combined result of physical environment, interpersonal relations, stressing factors and the reward and penalty system, among others, influences student motivation, readiness to study and academic achievement. Educational environment assessment focuses on student perception of the context beyond what might be "objectively" appreciated by an external observer. Objective: The aim of this study is to present results obtained from the application of a local version of the PHEEM questionnaire to cardiology residents to explore whether their perception differs according to hospital public or private condition. Methods: We applied the PHEEM (Postgraduate Hospital Educational Environment Measure) questionnaire, developed by S. Roff, S. McAleer and A. Skinner, which is a specific tool to assess educational environment in the hospital setting. Results: One hundred and forty eight residents from 31 Buenos Aires City and Greater Buenos Aires hospitals, who attended the 2012 Biennial Cardiology Course, completed the questionnaire: 71 residents from public hospitals, 75 from private hospitals and 2 who did not identify hospital condition. Private hospital residencies showed significantly better learning conditions. Differences were found in supervision availability, sanitation facilities and resting / meeting rooms for doctors on call, the sense of physical security inside the hospital and the adequate number of patients and studies for learning. There were no differences regarding the high level of exigency, poor feedback and lack of "protected" time to study during working week hours. Conclusions: It would be necessary to evaluate other specialty residencies and programs implemented in other jurisdictions, to analyze whether this is a general conclusion or it only applies to cardiology residencies in the metropolitan area.

Escolas traçadas com régua e compasso na Colômbia e no Brasil / Schools drawn with a ruler and a compass in Colombia and Brazil

Com este artigo, que é parte de uma pesquisa mais ampla, pretendemos refletir sobre o processo de escolarização da infância, em duas revistas destinadas à formação de professores para o magistério. Ambas produzidas por grupos articulados a políticas educacionais e divulgadas para as redes públicas de ensino de São Paulo (Brasil) e outra para Bogotá (Colômbia), de 1932 a 1939. Fizemos duas perguntas às revistas: O que podem nos dizer sobre as finalidades políticas da formação de professores para o magistério? E sobre as relações entre os métodos científicos da psicologia e da pedagogia? No final, apresentamos nossas suspeitas de cumplicidade entre projetos pedagógicos e projetos políticos autoritários, atuando no conjunto das forças cognitivas, psicológicas, culturais e institucionais.

Cáncer inflamatorio de la mama: aspectos clínicos y tratamiento / Inflammatory carcinoma of the breast: clinical aspects and treatment

Presentar la incidencia, manifestaciones clínicas más frecuentes, y el tratamiento del carcinoma inflamatorio de la mama en el Hospital Oncológico Padre Machado. Se revisaron en forma retrospectiva, historias médicas con diagnóstico de cáncer de mama localmente avanzado, encontrándose 24 pacientes con diagnóstico de cáncer inflamatorio, tratadas en el Servicio de Patología Mamaria del Hospital Oncológico Padre Machado, entre enero 1992 y diciembre 2004. La edad promedio fue de 47,8 años, 66,67 por ciento fueron premenopáusicas; 58,33 por ciento se ubicó en toda la mama, la induración, edema, eritema se presentó en un 62,50 por ciento, 91,67 por ciento y 95,83 por ciento, respectivamente. En todas las pacientes el diagnóstico fue realizado con biopsia incisional que incluyó la piel. El 50 por ciento de las pacientes presentaron plastrones axilares y el 16, 67 por ciento fueron metastásicos al momento del diagnóstico. El 93,33 por ciento de las pacientes recibió quimioterapia primaria, la cirugia se realizó en el 66,67 por ciento de las pacientes; siendo las mastectomía radical modificada la más frecuente. El 54,17 por ciento fueron receptores estrogénicos positivos. Nueve pacientes tuvieron recurrencia a distancia (37,50 por ciento). El 66,7 por ciento de las pacientes, presentan probabilidad de recaída sistémica en 33,5 meses. La sobrevida promedio de estas pacientes fue de 15,73 meses. A pesar de ser una entidad poco frecuente, con una diseminación sistémica precoz, alta posibilidad de recidiva locorregional y poca respuesta al tratamiento, es importante su diagnóstico para poder instaurar un tratamiento adecuado

Uso del bisturí armónico: en la cirugía tiroidea / Use of the harmonic scalpel: In thyroid surgery

El propósito de este estudio, es investigar la utilidad del uso del bisturí armónico en el tratamiento de la patología tiroidea. Aunado a los avances existentes en los estudios imaginológicos, sobre todo el ultrasonido, ultrasonido Doppler y, la instauración de la punción aspiración con aguja fina en los pacientes con nódulos tiroideos, el bisturí armónico permite no sólo ahorrar tiempo quirúrgico, sino que disminuye significativamente la posibilidad de complicaciones. El uso de este equipo ha evolucionado a la par del desarrollo de la cirugía laparoscópica, que ha permitido el uso de técnicas novedosas el desarrollo de la cirugía mínimamente invasiva. La tiroidectomía efectuada con bisturí armónico es un procedimiento factible, con escasas complicaciones y que permite principalmente ahorrar tiempo quirúrgico, lo cual redundará en los costos finales de la cirugía.

The purpose of this study is to investigate the utility of the use of the harmonic scalpel in the treatment of the thyroid pathology. Joined to the existent advances in the imaginologic studies, ultrasound and Doppler and setting-up of the fine-needle aspiration in patients with thyroid nodules, the harmonic scalpel only allows not to save surgical time, but rather it diminishes the possibility of complications significantly. The use of this scalpel has evolved at same time of the development of the laparoscopic surgery, which has allowed the use of technical novel the development of the minimally invasive thyroidectomy. The thyroidectomy made with harmonic scalpel is a feasible procedure, with low complications and that allows mainly saving surgical time, that which will redound in the final costs of the surgery.

Sarcoma radioinducido: en el área de cabeza y cuello / Radiotherapy-induced sarcoma: in the head and neck area

El desarrollo de sarcomas durante el curso de tratamiento de una lesión maligna previa es inusual. El origen de estos tumores y los factores promotores de este son controversiales. Hay diversos reportes que afirman categóricamente la inducción de apariciones de sarcomas posterior a administración de radioterapia. Pacientes curados de una lesión maligna tienen una significativa probabilidad de desarrollar otros tumores. Numerosas han sido las publicaciones han documentado la frecuencia de segundas neoplasias malignas asociadas con radioterapia en pacientes que han sobrevivido a su tumor primario. Hay muchos ejemplos que podemos mencionar de carcinogenesis en humanos posterior a irradiación: Individuos que han sido tratados con radioterapia para espondilitis anquilosante, uso de Rayos X en pacientes embarazadas, tratamiento de tiña capitis, uso de energía nuclear en conflictos bélicos, etc. El caso que describimos es un joven con antecedente de rabdomiosarcoma alveolar en parpado inferior y diez y siete años más tarde; se presenta con leiomiosarcoma radioinducido a nivel etmoidal. Se discute su manejo y se revisa la literatura a partir de su descripción por Cahan y colegas en 1948

Cáncer primario de vagina: experiencia en el Hospital Oncológico Padre Machado (1988-1998) / Primary cancer of vagina: experience in the Hospital Oncológico Padre Machado (1988-1998)

Los carcinomas primarios de vagina sólo representan entre el 1-2 por ciento de todos los tumores malignos del área ginecológica. El objetivo del presente trabajo es de evaluar nuestra experiencia en el manejo de esta neoplasia. Se revisó la casuística de nuestro Hospital entre 1988 y 1998, encontrado solo 11 pacientes con este tipo de lesión. En cuanto a los resultados obtenidos, se encontró que la edad promedio fue 46,73 años, con un rango comprendido entre 29 y 76 años. El tipo histológico más frecuente fue el carcinoma epidermoide (90,9 por ciento), seguido del adenocarcinoma (9,1 por ciento). La asociación con el VPH fue del 45,5 por ciento. Según la clasificación de la FIGO, los estadio de la enfermedad fueron 3 (27,3 por ciento) en estadio I, 5 (45,5 por ciento) en estadio II y 3 (27,3 por ciento) en estadio III. El tratamiento con radioterapia se realizó en 10 pacientes. Se indicó quimioterapia concurrente a una de las pacientes irradiadas. Hubo persistencia de enfermedad en 3 casos (27,35 por ciento) y recidiva en tres casos (27,35 por ciento). Se realizó vaginectomía en dos pacientes con recidiva. La tasa de sobrevida actuarial a los 4 años fue del 60 por ciento. Concluimos que es una patología ginecológica poco frecuente cuyo tratamiento primario de elección es la radioterapia