2,438 research outputs found
História e arquivística
As diversas correntes metodológicas da historiografia contemporânea têm profundas implicações na doutrina arquivística, entendida quer como tecnologia, quer como pesquisa histórica. No trabalho de reconstituição das séries e fundos, a arquivística foi um fator incisivo no desenvolvimento da historiografia mundial. A historiografia e a arquivística, com os seus métodos e objetos próprios, desenvolvem-se como disciplinas interdependentes e autônomas
Institutionalising the dirt trail. Prompt, participatory and self-built urban upgrading processes in Berlin.
This research aims to analyse the complexity of the very delicate moment when the “dirt trial” of temporary uses – with all its related practices – meets the actors of conventional development and economy in a process of institutional reframing. Which are the factors encouraging fruitful collaborations among actors which would be normally lined up poles apart? Is it possible to overpass the impasse which sets the bottom-up against the top-down in favour of a new idea of developing the urban space based on dialogue, mediation and cross-fertilisation
Impaired myocardial relaxation with exercise determines peak aerobic exercise capacity in heart failure with preserved ejection fraction
Background
Heart failure with preserved ejection fraction (HFpEF) is a clinical syndrome characterized by impaired exercise capacity due to shortness of breath and/or fatigue. Assessment of diastolic dysfunction at rest and with exercise may provide insight into the pathophysiology of exercise intolerance in HFpEF. Aims
To measure echocardio-Doppler-derived parameters of diastolic function as they relate to various indices of aerobic exercise capacity in HFpEF. Methods
We selected 16 subjects with clinically stable HFpEF, no evidence of volume overload, but impaired functional capacity by cardiopulmonary exercise testing [peak oxygen consumption (VO2)]. We measured the transmitral E and A flow velocities, E/A ratio, and E deceleration time (DT) and tissue Doppler E′ velocity. We also indexed the E′ to the DT, as additional measure of impaired relaxation (E′DT), and calculated the diastolic functional reserve index (DFRI), as the product of E′ at rest and change in E′ with exercise. Results
E′ velocity, at rest and peak exercise, as well as the DFRI positively correlated with peak VO2, whereas DT, E′DT, and E/E′ with exercise inversely correlated with peak VO2. Of note, the E′DT at rest also significantly predicted E′ velocity at peak exercise (R = +0.81, P \u3c 0.001). Exercise E′ was the only independent predictor of peak VO2 at multivariable analysis (R = +0.67, P = 0.005). Conclusions
The E′ velocity at peak exercise is a strong and independent predictor of aerobic exercise capacity as measured by peak VO2 in patients with HFpEF, providing the link between abnormal myocardial relaxation with exercise and impaired aerobic exercise capacity in HFpEF
Interleukin-18 mediates cardiac dysfunction induced by western diet independent of obesity and hyperglycemia in the mouse
Obesity and diabetes are independent risk factors for heart failure and are associated with the consumption of diet rich in saturated fat and sugar, Western diet (WD), known to induce cardiac dysfunction in the mouse through incompletely characterized inflammatory mechanisms. We hypothesized that the detrimental cardiac effects of WD are mediated by interleukin-18 (IL-18), pro-inflammatory cytokine linked to cardiac dysfunction. C57BL/6J wild-type male mice and IL-18 knockout male mice were fed high-saturated fat and high-sugar diet for 8 weeks. We measured food intake, body weight and fasting glycemia. We assessed left ventricular (LV) systolic and diastolic function by Doppler echocardiography and cardiac catheterization. In wild-type mice, WD induced a significant increase in isovolumetric relaxation time, myocardial performance index and left ventricular end-diastolic pressure, reflecting an impairment in diastolic function, paired with a mild reduction in LV ejection fraction. IL-18 KO mice had higher food intake and greater increase in body weight without significant differences in hyperglycemia. Despite displaying greater obesity, IL-18 knockout mice fed with WD for 8 weeks had preserved cardiac diastolic function and higher left ventricular ejection fraction. IL-18 mediates diet-induced cardiac dysfunction, independent of food intake and obesity, thus highlighting a disconnect between the metabolic and cardiac effects of IL-18
Interleukin-1 blockade in recently decompensated systolic heart failure: study design of the recently decompensated heart failure anakinra response trial (RED-HART)
Heart Failure (HF) is a clinical syndrome characterized by
dyspnea, fatigue, and poor exercise capacity due to impaired cardiac
function. The incidence of HF is increasing and represents the leading
cause of hospitalization in the United States among patients > 65 years
of age. Neurohormonal blockade has proven to reduce morbidity
and mortality; however the persistent toll of HF demonstrates the
urgent need to continue to develop novel drugs that target other
pathophysiological paradigms. The presence of inflammation in
cardiovascular disease has been well-established and interleukin-1
(IL-1), the prototypical proinflammatory agent, has been shown in
preclinical animal models to induce cardiac dysfunction. The current
study will investigate the role of IL-1 as an inflammatory mediator of
HF progression and investigate whether IL-1 blockade with anakinra,
recombinant human IL-1 receptor antagonist, improves aerobic
exercise performance in patients with recently decompensated
systolic HF. This study will be composed of 3 treatment arms (20
patients each): 1) anakinra 100mg daily for 12 weeks; 2) anakinra
100mg daily for 2 weeks followed by placebo for 10 weeks; or 3)
placebo for 12 weeks. All patients will be followed for at least 24
weeks. The co-primary endpoints will be placebo-corrected interval
changes in peak oxygen consumption (VO2) and ventilatory efficiency
(VE/VCO2 slope) measured by Cardiopulmonary Exercise Testing
(CPX) after 2 weeks of anakinra treatment. Secondary endpoints will
include interval changes in 1) CPX variables at 4, 12 and 24 weeks;
2) echocardiographic measures of cardiac dimension/function; 3)
quality of life assessments; 4) inflammatory biomarkers; and 5) clinical
outcome including days alive outside of the hospital and survival free
of re-hospitalization for HF. The RED-HART study will be the first
study to address the potential benefits of IL-1 blockade on aerobic
exercise performance in patients with recently decompensated HF
Low NT-proBNP levels in overweight and obese patients do not rule out a diagnosis of heart failure with preserved ejection fraction
Background Heart failure with preserved ejection fraction (HFpEF) is a heterogeneous syndrome that presents clinicians with a diagnostic challenge. The use of natriuretic peptides to exclude a diagnosis of HFpEF has been proposed. We sought to compare HFpEF patients with N-terminal pro-brain natriuretic peptide (NT-proBNP) level above and below the proposed cut-off. Methods Stable patients (n = 30) with left ventricular (LV) ejection fraction ≥ 50% were eligible if they had a diagnosis of HF according to the European Society of Cardiology diagnostic criteria. Characteristics of patients with NT-proBNP below (≤125 pg/mL) and above (\u3e125 pg/mL) the diagnostic criterion were compared. Results There were 19 (66%) women with median age 54 years. Half were African American (16, 53%), and most were obese. There were no significant differences in clinical characteristics or medication use between groups. LV end-diastolic volume index was greater in high NT-proBNP patients (P = 0.03). Left atrial volume index, E/e\u27 ratio, and E/e\u27 ratio at peak exercise were not significantly different between NT-proBNP groups. Peak oxygen consumption (VO2), VO2 at ventilatory threshold, and ventilatory efficiency measures were impaired in all patients and were not significantly different between high and low NT-proBNP patients. Conclusions NT-proBNP was below the proposed diagnostic cut-off point of 125 pg/mL in half of this obese study cohort. Cardiac diastolic dysfunction and cardiorespiratory fitness were not significantly different between high and low NT-proBNP patients. These data indicate that excluding the diagnosis of HFpEF based solely on NT-proBNP levels should be discouraged
Validity of the Actigraph GT9X Accelerometer Step-Count Function in Adults with Heart Failure with Preserved Ejection Fraction
Low physical activity is associated with heart failure with preserved ejection fraction (HFpEF). Step-counts, a measure of physical activity, can be measured via accelerometry. To date, few studies have examined validity of accelerometer-derived step-counts in the adults with HFpEF.
PURPOSE To assess criterion validity of the Actigraph GT9X accelerometer step-count function in adults with HFpEF via ankle, waist, and wrist placement, compared with manually counted, directly observed steps.
METHODS Six adults with HFpEF (age: 57.2 ± 9.4 y; African American: 50%; females: 100%) completed a cardiopulmonary exercise test (CPET) on a treadmill while wearing synchronized GT9X accelerometers on the ankle, waist, and wrist. Steps during CPET were measured by using the step-count function on the GT9X at 60 Hz sampling and data were downloaded into 1-second and 10-second epochs. Hand-tallied, directly observed steps (OS) was the criterion measure. Criterion validity was assessed via paired t tests to determine whether mean total steps (TS) from the three devices were significantly different from the mean TS from OS, and Pearson correlations were used to determine associations between device-measured TS and the total OS. Simple linear regression models were used to assess the effect of walking speed on absolute percentage error of the devices compared to OS. Agreement of the devices throughout the duration of the CPET was examined using Pearson correlations. Alpha was set at 0.05 for all statistical analyses.
RESULTS Mean TS from waist-worn (t = -5.29, p = .001) and wrist-worn (t = -12.50, p \u3c .001) devices were significantly lower than mean TS from OS. Only TS from the ankle GT9X was significantly associated with TS from OS (r = 0.974, p = .001). GT9X-estimate steps from the ankle (r = 0.869, p \u3c .001), waist (r = 0.550, p \u3c.001), and wrist (r = 0.429, p \u3c.001) were all significantly associated with OS-measured steps. Absolute percentage error was significantly and negatively associated with treadmill speed for devices on the ankle (b = - 10.70, p \u3c .001), waist (b = -32.49, p \u3c .001) and wrist (b = -10.08, p \u3c .001).
CONCLUSION Our results suggest that accelerometer-derived TS may be a more accurate measure of TS when the device is worn on the ankle rather than waist or wrist, and that measurement error is higher at lower walking speed.https://scholarscompass.vcu.edu/gradposters/1153/thumbnail.jp
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