Stress-Induced Cardiomyopathy

Stress-induced cardiomyopathy is a relatively uncommon syndrome with difficult definition. Cases with transient and reversible left ventricular dysfunction, precipitated by emotional stress and without coronary artery disease, are called takotsubo syndrome, left ventricular apical ballooning, and broken heart syndrome. Many names used to refer to this syndrome are related to the shape of the left ventricle and/or the precipitating factors, but there is not yet a consensus about the proper name. Situations related to physical stress, such as intracranial bleeding, have similar patterns, including the absence of previous cardiac involvement. The increased blood levels of endogenous catecholamine, and increase of myocardial catecholamine in areas with high density of sympathetic innervations, seem to be the mechanisms for myocardial cell necrosis with eosinophilic transverse bands. The localized spasm of the epicardial coronaries, or diffuse microcirculatory dysfunction, is also one of the proposed mechanisms. There are still some areas of controversy that have no definite answer.Facultad de Ciencias Médica

Diagnostic role of new Doppler index in assessment of renal artery stenosis

Background: Renal artery stenosis (RAS) is one of the main causes of secondary systemic arterial hypertension. Several non-invasive diagnostic methods for RAS have been used in hypertensive patients, such as color Doppler ultrasound (US). The aim of this study was to assess the sensitivity and specificity of a new renal Doppler US direct-method parameter: the renal-renal ratio (RRR), and compare with the sensitivity and specificity of direct-method conventional parameters: renal peak systolic velocity (RPSV) and renal aortic ratio (RAR), for the diagnosis of severe RAS. Methods: Our study group included 34 patients with severe arterial hypertension (21 males and 13 females), mean age 54 (± 8.92) years old consecutively evaluated by renal color Doppler ultrasound (US) for significant RAS diagnosis. All of them underwent digital subtraction arteriography (DSA). RAS was significant if a diameter reduction 200 cm/s with 97% sensitivity, 72% specificity, 81% positive predictive value and 95% negative predictive value; RAR >3 with 77% sensitivity, 90% specificity, 90% positive predictive value and 76% negative predictive value. The optimal sensitivity and specificity cutoff for the new RRR was >2.7 with 97% sensitivity (p 200cm/s and RAR >3). Both RRR and RPSV show better sensitivity than RAR for the RAS diagnosis.Facultad de Ciencias Médica

Factors Affecting Infestation by Triatoma infestans in a Rural Area of the Humid Chaco in Argentina: A Multi-Model Inference Approach

Vector-borne transmission of Chagas disease remains a major public health problem in parts of Latin America. Triatoma infestans is the main vector in the countries located in the South American Cone, particularly in the Gran Chaco ecoregion where residual insecticide control has achieved only a moderate, irregular impact. To contribute to improved control strategies, we analyzed the factors associated with the presence and abundance of T. infestans in 327 inhabited houses in a well-defined rural area with no recent vector control interventions in the humid Argentine Chaco. Bugs were found mainly in domiciles, kitchens, storerooms, and chicken coops and nests, particularly where adequate refuge and animal hosts (humans, dogs, cats or poultry) were available. Domiciles constructed from mud were the most often infested, but brick-and-cement domiciles, even in good conditions, were also found infested. Availability of refuge and hosts for T. infestans are key targets for vector control. Ten-fold variations in domestic infestation observed across neighboring villages, and differences in the relevant factors for T. infestans presence with respect to other areas of the Gran Chaco region suggest that host management, building techniques and insecticide use need to be tailored to the local environment, socio-economic characteristics, and climatic conditions

Consistent patterns of common species across tropical tree communities

Trees structure the Earth’s most biodiverse ecosystem, tropical forests. The vast number of tree species presents a formidable challenge to understanding these forests, including their response to environmental change, as very little is known about most tropical tree species. A focus on the common species may circumvent this challenge. Here we investigate abundance patterns of common tree species using inventory data on 1,003,805 trees with trunk diameters of at least 10 cm across 1,568 locations1,2,3,4,5,6 in closed-canopy, structurally intact old-growth tropical forests in Africa, Amazonia and Southeast Asia. We estimate that 2.2%, 2.2% and 2.3% of species comprise 50% of the tropical trees in these regions, respectively. Extrapolating across all closed-canopy tropical forests, we estimate that just 1,053 species comprise half of Earth’s 800 billion tropical trees with trunk diameters of at least 10 cm. Despite differing biogeographic, climatic and anthropogenic histories7, we find notably consistent patterns of common species and species abundance distributions across the continents. This suggests that fundamental mechanisms of tree community assembly may apply to all tropical forests. Resampling analyses show that the most common species are likely to belong to a manageable list of known species, enabling targeted efforts to understand their ecology. Although they do not detract from the importance of rare species, our results open new opportunities to understand the world’s most diverse forests, including modelling their response to environmental change, by focusing on the common species that constitute the majority of their trees.Publisher PDFPeer reviewe

Stress-Induced Cardiomyopathy

Stress-induced cardiomyopathy is a relatively uncommon syndrome with difficult definition. Cases with transient and reversible left ventricular dysfunction, precipitated by emotional stress and without coronary artery disease, are called takotsubo syndrome, left ventricular apical ballooning, and broken heart syndrome. Many names used to refer to this syndrome are related to the shape of the left ventricle and/or the precipitating factors, but there is not yet a consensus about the proper name. Situations related to physical stress, such as intracranial bleeding, have similar patterns, including the absence of previous cardiac involvement. The increased blood levels of endogenous catecholamine, and increase of myocardial catecholamine in areas with high density of sympathetic innervations, seem to be the mechanisms for myocardial cell necrosis with eosinophilic transverse bands. The localized spasm of the epicardial coronaries, or diffuse microcirculatory dysfunction, is also one of the proposed mechanisms. There are still some areas of controversy that have no definite answer.Facultad de Ciencias Médica

Estudio comparativo del pleuston en cuatro lagunas de la provincia de Buenos Aires

En esta contribución se pretende intentar un análisis comparativo de la composición cuali y cuantitativa de la "comunidad" denominada Pleuston tal como se presenta en un conjunto de lagunas de la provincia de Buenos Aires a nivel de su mesofauna.De acuerdo con Ringuelet (1962) el pleuston queda definido como el conjunto de organismos vinculados a la vegetación flotante. No es nuestra intención, en esta ocasión, abrir juicio sobre si este posee propiedadessuficientes para ser considerado una comunidad real, optando por lo tanto para futuros trabajos la consideración de este tema

Left Ventricular Diastolic Function in Healthy Adult Individuals: Results of the World Alliance Societies of Echocardiography Normal Values Study

Background: The World Alliance Societies of Echocardiography (WASE) study was conducted to describe echocardiographic normal values in adults and to compare races and nationalities using a uniform acquisition and measurement protocol. This report focuses on left ventricular (LV) diastolic function.Methods: WASE is an international, cross-sectional study. Participants were enrolled with equal distribution according to age and gender. Echocardiograms were analyzed in a core laboratory based on the latest American Society of Echocardiography/European Association of Cardiovascular Imaging guidelines. Left ventricular diastolic function was assessed by E, E/A, e' velocities, E/e', left atrial volume index (LAVI), and tricuspid regurgitation velocity. Determination of LV diastolic function was made using the algorithm proposed by the guidelines.Results: A total of 2,008 subjects from 15 countries were enrolled. The majority were of white or Asian race (42.8%, 41.8%, respectively). E and E/e' were higher in female patients, while LAVI was similar in both genders. Consistent increase in E/e' and decrease in E/A, E, and e' were found as age increased. The upper limit of normal for LAVI was higher in WASE compared with the guidelines. The lower limits of normal for e' were smaller in elder groups than those in the guidelines, while the upper limits of normal for E/e' were below the guideline values. These findings suggest that the cutoff value for LAVI should be shifted upward and age-specific cutoff values for e' should be considered. In WASE, <93.6% of patients were classified as normal LV diastolic function using the guidelines' algorithm, and the proportion increased to 97.4% when applying the revised cutoff values for LAVI obtained in our study.Conclusions: Guideline-recommended normal values for e' velocities and LAVI should be reconsidered. The algorithm for the determination of LV diastolic function proposed by the guidelines is useful, but adjustments to LAVI could further improve it

Normal Values of Three-Dimensional Right Ventricular Size and Function Measurements: Results of the World Alliance Societies of Echocardiography Study

Background: Normal values for three-dimensional (3D) right ventricular (RV) size and function are not well established, as they originate from small studies that involved predominantly white North American and European populations, did not use RV-focused views, and relied on older 3D RV analysis software. The World Alliance Societies of Echocardiography study was designed to generate reference ranges for normal subjects around the world. The aim of this study was to assess the worldwide capability of 3D imaging of the right ventricle and report size and function measurements, including their dependency on age, sex, and ethnicity. Methods: Healthy subjects free of cardiac, pulmonary, and renal disease were prospectively enrolled at 19 centers in 15 countries, representing six continents. Three-dimensional wide-angle RV data sets were obtained and analyzed using dedicated RV software (TomTec) to measure end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume, and ejection fraction (EF). Results were categorized by sex, age (18-40, 41-65, and >65 years) and ethnicity. Results: Of the 2,007 subjects with attempted 3D RV acquisitions, 1,051 had adequate image quality for confi-dent measurements. Upper and lower limits for body surface area-indexed EDV, ESV, and EF were 48 and 95 mL/m2, 19 and 43 mL/m2, and 44% and 58%, respectively, for men and 42 and 81 mL/m2, 16 and 36 mL/m2, and 46% and 61%, respectively, for women. Men had significantly larger EDVs, ESVs, and stroke volumes (even after body surface area indexing) and lower EFs than women (P < .05). EDV and ESV did not show any meaningful differences among age groups. Three-dimensional RV volumes were smallest in Asians. Conclusions: Reliability of 3D RV acquisition is low worldwide, underscoring the importance of future improve-ments in imaging techniques. Sex and race must be taken into consideration in the assessment of both RV volumes and EF. (J Am Soc Echocardiogr 2023;36:858-66.