Exercise capacity and cardiac hemodynamic response in female ApoE/LDLR^{-/-} mice : a paradox of preserved V'O_{2max} and exercise capacity despite coronary atherosclerosis

We assessed exercise performance, coronary blood flow and cardiac reserve of female ApoE/LDLR-/- mice with advanced atherosclerosis compared with age-matched, wild-type C57BL6/J mice. Exercise capacity was assessed as whole body maximal oxygen consumption (V'O2max), maximum running velocity (vmax) and maximum distance (DISTmax) during treadmill exercise. Cardiac systolic and diastolic function in basal conditions and in response to dobutamine (mimicking exercise-induced cardiac stress) were assessed by Magnetic Resonance Imaging (MRI) in vivo. Function of coronary circulation was assessed in isolated perfused hearts. In female ApoE/LDLR-/- mice V'O2max, vmax and DISTmax were not impaired as compared with C57BL6/J mice. Cardiac function at rest and systolic and diastolic cardiac reserve were also preserved in female ApoE/LDLR-/- mice as evidenced by preserved fractional area change and similar fall in systolic and end diastolic area after dobutamine. Moreover, endothelium-dependent responses of coronary circulation induced by bradykinin (Bk) and acetylcholine (ACh) were preserved, while endothelium-independent responses induced by NO-donors were augmented in female ApoE/LDLR-/- mice. Basal COX-2-dependent production of 6-keto-PGF1α was increased. Concluding, we suggest that robust compensatory mechanisms in coronary circulation involving PGI2- and NO-pathways may efficiently counterbalance coronary atherosclerosis-induced impairment in V'O2max and exercise capacity

Poluição atmosférica e internações hospitalares por doenças respiratórias em crianças e adolescentes em Cubatão, São Paulo, Brasil, entre 1997 e 2004 Air pollution and pediatric hospital admissions due to respiratory diseases in Cubatão, São Paulo State, Brazil, from 1997 to 2004

O objetivo deste estudo foi avaliar os efeitos dos poluentes atmosféricos e suas estruturas de defasagem sobre a morbidade respiratória de crianças e adolescentes, na cidade de Cubatão, São Paulo, Brasil, entre 1997 e 2004. Um estudo ecológico de séries temporais foi realizado, analisando internações nos hospitais do Sistema Único de Saúde por doenças respiratórias de crianças e adolescentes residentes no município. Foram utilizados modelos lineares generalizados de regressão de Poisson, controlando-se para sazonalidade, temperatura, umidade e tendência de curta duração. PM10 e ozônio estiveram positiva e estatisticamente associados com as internações por doenças respiratórias. No grupo de crianças, aumentos de um interquartil nas médias móveis de sete dias do PM10 (56,5µg/m³) e de cinco dias do ozônio (46,7µg/m³) levaram a aumentos nas internações hospitalares de 9,6% (IC95%: 3,0%-16,1%) e 2,4% (IC95%: 0,1%-4,7%), respectivamente. Esforços para redução das concentrações dos poluentes do ar ainda precisam ser implementados para minimizar os seus efeitos adversos sobre crianças e adolescentes em Cubatão.The aim of this study was to evaluate the effects of air pollutants and their lag structures in relation to respiratory morbidity among children and adolescents in the city of Cubatão, São Paulo State, Brazil, from 1997 to 2004. An ecological time-series study was performed, analyzing respiratory hospital admissions of children and adolescents in National Health System hospitals in Cubatão. Generalized linear Poisson regression models were used to control for seasonality, temperature, humidity, and short-term trends. PM10 and ozone were significantly associated with respiratory hospital admissions. Among children, inter-quartile range increases in the PM10 7-day moving average (56.5µg/m³) and in the ozone 5-day moving average (46.7µg/m³) led to increases of 9.6% (95%CI: 3.0%-16.1%) and 2.4% (95%CI: 0.1%-4.7%) in respiratory hospital admissions, respectively. Efforts to reduce air pollutants need to be adopted to minimize the adverse effects on children and adolescents in Cubatão

Effect of Dolomite Addition on the Structure and Properties of Multicomponent Amphibolite Glasses

The structure and properties of the glass can be modified by introducing appropriate additives. Dolomite is one of the primary raw materials modifying the properties of glass, in which the essential component is calcium-magnesium double carbonate CaCO3∙MgCO3. The paper presents the research results on glasses obtained by smelting pure amphibolite and amphibolite modified with 10 and 20% dolomite additives. The raw material used was mined in the Poland region of Lower Silesia. The glass melting process was carried out in an electric furnace at 1450 °C for 2 h. The structure and properties of the glasses and crystallization products were determined by Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy—Energy Dispersive Spectroscopy (SEM-EDS). Viscosity and Vickers microhardness were also measured. It was found that the modification of amphibolite glass by adding dolomite affects the glasses’ properties and structure. The research results determined the effect of dolomite addition on the properties of alumino-silicate glasses in terms of the mineral fibre products used in the construction industry

Comprehensive MRI for the detection of subtle alterations in diastolic cardiac function in apoE/LDLR^{-/-} mice with advanced atherosclerosis

ApoE/LDLR-/- mice represent a reliable model of atherosclerosis. However, it is not clear whether cardiac performance is impaired in this murine model of atherosclerosis. Here, we used MRI to characterize cardiac performance in vivo in apoE/LDLR-/- mice with advanced atherosclerosis. Six-month-old apoE/LDLR-/- mice and age-matched C57BL/6J mice (control) were examined using highly time-resolved cine-MRI [whole-chamber left ventricle (LV) imaging] and MR tagging (three slices: basal, mid-cavity and apical). Global and regional measures of cardiac function included LV volumes, kinetics, time-dependent parameters, strains and rotations. Histological analysis was performed using OMSB (orceine with Martius, Scarlet and Blue) and ORO (oil red-O) staining to demonstrate the presence of advanced coronary atherosclerosis. MR-tagging-based strain analysis in apoE/LDLR-/- mice revealed an increased frequency of radial and circumferential systolic stretch (25% and 50% of segments, respectively, p≤0.012), increased radial post-systolic strain index (45% of segments, p=0.009) and decreased LV untwisting rate (-30.3° (11.6°)/cycle, p=0.004) when compared with control mice. Maximal strains and LV twist were unchanged. Most of the cine-MRI-based LV functional and anatomical parameters also remained unchanged in apoE/LDLR-/-mice, with only a lower filling rate, longer filling time, shorter isovolumetric contraction time and slower heart rate observed in comparison with control mice. The coronary arteries displayed severe atherosclerosis, as evidenced by histological analysis. Using comprehensive MRI methods, we have demonstrated that, despite severe coronary atherosclerosis in six-month-old apoE/LDLR-/- mice, cardiac performance including global parameters, twist and strains, was well preserved. Only subtle diastolic alterations, possibly of ischemic background, were uncovered

Analysis of Outcomes in Ischemic vs Nonischemic Cardiomyopathy in Patients With Atrial Fibrillation A Report From the GARFIELD-AF Registry

IMPORTANCE Congestive heart failure (CHF) is commonly associated with nonvalvular atrial fibrillation (AF), and their combination may affect treatment strategies and outcomes