instruction:
Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.
question:
Context: To investigate the significance of respiratory muscle weakness in chronic heart failure and its relation both to maximum oxygen consumption during cardiopulmonary exercise testing and to skeletal muscle (quadriceps) strength.', 'Seven healthy men aged 54.9 (SEM 4.3) years and 20 men with chronic heart failure aged 61.4 (1.6) years (P = 0.20) with radionuclide left ventricular ejection fraction of 25.4 (3.0)%.', 'Mouth pressures during maximum static inspiratory effort (PImax) at functional residual capacity (FRC) and residual volume (RV) were measured in all subjects and taken as indices of inspiratory muscle strength. Similarly, mouth pressures during maximum static expiratory effort (PEmax) at FRC and total lung capacity (TLC) were taken as indices of expiratory muscle strength. Cardiopulmonary exercise testing was performed in all subjects. All controls and 15 heart failure patients also had their right quadriceps muscle strength measured.', 'There was respiratory muscle weakness in heart failure patients, with reduction of PImax at FRC (59.7) (6.3) v 85.6 (9.6) cm H2O, P = 0.045), PEmax at FRC (94.8 (6.2) v 134.6 (9.1) cm H2O, P = 0.004), and PEmax at TLC (121.7 (8.5) v 160.7 (13) cm H2O, P = 0.028). PImax at RV was also reduced but this did not reach statistical significance (77.3 (6.6) v 89.3 (13) cm H2O, P = 0.44). There was also significant weakness of the right quadriceps muscle (308.5 (22) v 446.2 (28) N, P = 0.001). PImax at both FRC and RV correlated with maximum oxygen consumption (r = 0.59, P = 0.006, and r = 0.45, P = 0.048 respectively) but not PEmax. There was, however, no significant correlation between PImax and right quadriceps strength.
Answer: Respiratory muscle weakness is seen in chronic heart failure. The results suggest that inspiratory muscles are important in determining maximum oxygen consumption and exercise tolerance in these patients. The lack of correlation between respiratory and right quadriceps muscle strength further suggests that the magnitude and time course of respiratory and locomotor muscle weakness may differ in individual patients. Treatment aimed at improving the function of the involved muscle groups may alleviate symptoms.
answer:
Is inspiratory muscle strength a determinant of maximum oxygen consumption in chronic heart failure?


question:
Context: Surfactant protein (SP) D shares target cells with the proinflammatory cytokine TNF-alpha, an important autocrine stimulator of dendritic cells and macrophages in the airways.', 'We sought to study the mechanisms by which TNF-alpha and SP-D can affect cellular components of the pulmonary innate immune system.', 'Cytokine and SP-D protein and mRNA expression was assessed by means of ELISA, Western blotting, and real-time PCR, respectively, by using in vivo models of allergic airway sensitization. Macrophage and dendritic cell phenotypes were analyzed by means of FACS analysis. Maturation of bone marrow-derived dendritic cells was investigated in vitro.', 'TNF-alpha, elicited either by allergen exposure or pulmonary overexpression, induced SP-D, IL-13, and mononuclear cell influx in the lung. Recombinant IL-13 by itself was also capable of enhancing SP-D in vivo and in vitro, and the SP-D response to allergen challenge was impaired in IL-13-deficient mice. Allergen-induced increase of SP-D in the airways coincided with resolution of TNF-alpha release and cell influx. SP-D-deficient mice had constitutively high numbers of alveolar mononuclear cells expressing TNF-alpha, MHC class II, CD86, and CD11b, characteristics of proinflammatory, myeloid dendritic cells. Recombinant SP-D significantly suppressed all of these molecules in bone marrow-derived dendritic cell cultures.
Answer: TNF-alpha can contribute to enhanced SP-D production in the lung indirectly through inducing IL-13. SP-D, on the other hand, can antagonize the proinflammatory effects of TNF-alpha on macrophages and dendritic cells, at least partly, by inhibiting production of this cytokine.
answer:
Does surfactant protein D inhibit TNF-alpha production by macrophages and dendritic cells in mice?


question:
Context: Previous studies have shown a relationship between intima-media thickness (IMT) of the common carotid artery and coronary artery disease (CAD). The role of IMT in the prediction of significant CAD has not been established.', 'To investigate the diagnostic accuracy of IMT measurement and the detection of carotid plaques in relation to cardiovascular risk factors in the prediction of significant CAD.', 'One hundred and seventy patients (121 men and 49 women; average age 58 +/- 11 years) undergoing selective coronary angiography were examined by carotid ultrasound. IMT was measured. Plasma lipid concentrations and other risk factors were determined.', 'Angiographically proven significant CAD was found in 138 (81%) of all patients. Carotid plaques were detected in 98 (58%) of all patients. Presence of carotid plaques in common carotid artery (P<0.001) and male sex (P<0.005) were found to be categorical risk factors for significant CAD but in multiple regression analysis only age (P=0.15), IMT (P<0.01), high density lipoprotein (HDL) cholesterol (P=0.02) and, less significantly, total cholesterol (P=0.09) were found to be independent parameters for the prediction of significant CAD. IMT of 0.75 mm was determined as a cut-off point for the detection of significant CAD (sensitivity 78%, specificity 79%, positive predictive value 95%, negative predictive value 41%, odds ratio 12.9, 95% CI 3.5 to 47.6).
Answer: The increase in IMT is the significant positive predictor of angiographically proven CAD; other predictors are high age, low HDL cholesterol and, less significantly, high total cholesterol. Presence of carotid plaques and male sex do not add any new information for the prediction of CAD once the predictors are considered.
answer:

Is intima-media thickness of the common carotid artery the significant predictor of angiographically proven coronary artery disease?