TASK DEFINITION: In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.
PROBLEM: Context: Microalbuminuria and impaired endothelium-dependent vasodilation are both predictors for cardiac events in patients with type 2 diabetes. The aim of the study was to evaluate whether microalbuminuria correlated with coronary endothelium-dependent vasodilation.', 'We evaluated 84 patients (47 men, mean age 50.5 +/- 5.9 years) with type 2 diabetes for 9.4 +/- 3.4 years, without angiographic coronary stenosis and without major cardiovascular risk factors or other confounding factors, for endothelium investigation. Quantitative coronary angiography was used to assess coronary artery response to cold pressor testing, used to assess endothelium-dependent vasodilation, and to isosorbide dinitrate (endothelium-independent vasodilation).', 'Endothelium-dependent vasodilation differed in the patients with and without microalbuminuria (changes in coronary artery diameter during cold pressor testing: -15.0 +/- 1.9% vs. -10.2 +/- 1.3%, respectively, P < 0.05) and correlated with urinary albumin excretion rate (r = -0.39, P = 0.003), diastolic blood pressure (r = 0.29, P < 0.01), and left ventricular mass index (r = -0.24, P < 0.05). Independent predictors for endothelium-dependent vasodilation were urinary albumin excretion rate (beta -0.04 [95% CI -0.07 to -0.01], P < 0.005) and left ventricular mass index (-0.26 [-0.49 to -0.05], P < 0.05). Endothelium-independent vasodilation was similar in both groups.\Question: Is impaired coronary endothelium-dependent vasodilation associated with microalbuminuria in patients with type 2 diabetes and angiographically normal coronary arteries?

SOLUTION: Type 2 diabetic patients with microalbuminuria have a more severely impaired coronary endothelium-dependent vasodilation than those with normoalbuminuria. These data suggest a common pathophysiological process for both coronary vasomotor abnormalities and microalbuminuria.

PROBLEM: Context: To assess how different imputation methods used to account for missing variance data in primary studies influence tests of heterogeneity and pooled results from a meta-analysis with continuous outcomes.', 'Point and variance estimates for changes in serum creatinine, glomerular filtration rate, systolic blood pressure, and diastolic blood pressure were variably reported among 48 primary longitudinal studies of living kidney donors (71%-78% of point estimates were reported, 8%-13% of variance data were reported). We compared the results of meta-analysis, which either were restricted to available data or used four methods to impute missing variance data. These methods used reported P-values, reported nonparametric summaries, results from other similar studies using multiple imputation, or results from estimated correlation coefficients.', 'Significant heterogeneity was present in all four outcomes regardless of the imputation methods applied. The random effects point estimates and 95% confidence intervals varied little across imputation methods, and the differences were not clinically significant.\Question: Do imputing variance estimates alter the conclusions of a meta-analysis with continuous outcomes : a case study of changes in renal function after living kidney donation?

SOLUTION: Different methods to impute the variance data in the primary studies did not alter the conclusions from this meta-analysis of continuous outcomes. Such reproducibility increases confidence in the results. However, as with most meta-analyses, there was no gold standard of truth, and results must be interpreted judiciously. The generalization of these findings to other meta-analyses, which differ in outcomes, missing data, or between-study heterogeneity, requires further consideration.

PROBLEM: Context: The mechanisms responsible for the cardiac dysfunction associated with dietary protein restriction (PR) are poorly understood. Thus, this study was designed to evaluate the effects of PR on calcium kinetics, basal and β-adrenergic contractility in murine ventricular cardiomyocytes.', 'After breastfeeding male Fisher rats were distributed into a control group (CG, n = 20) and a protein-restricted group (PRG, n = 20), receiving isocaloric diets for 35 days containing 15% and 6% protein, respectively. Biometric and hemodynamic variables were measured. After euthanasia left ventricles (LV) were collected for histopathological evaluation, SERCA2a expression, cardiomyocytes contractility and Ca(2+)sparks analysis.', 'PRG animals showed reduced general growth, increased heart rate and arterial pressure. These animals presented extracellular matrix expansion and disorganization, cardiomyocytes hypotrophy, reduced amplitudes of shortening and maximum velocity of contraction and relaxation at baseline and after β-adrenergic stimulation. Reduced SERCA2a expression as well as higher frequency and lower amplitude of Ca(2+)sparks were observed in PRG cardiomyocytes.\Question: Is basal and β-adrenergic cardiomyocytes contractility dysfunction induced by dietary protein restriction associated with downregulation of SERCA2a expression and disturbance of endoplasmic reticulum Ca2+ regulation in rats?

SOLUTION:
The observations reveal that protein restriction induces marked myocardial morphofunctional damage. The pathological changes of cardiomyocyte mechanics suggest the potential involvement of the β-adrenergic system, which is possibly associated with changes in SERCA2a expression and disturbances in Ca(2+) intracellular kinetics.