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Objective:To quantify any correlation between the severity of spinal curvature of an adolescent with idiopathic scoliosis and their cardiopulmonary exercise endurance.Methods:The cardiopulmonary exercise test (CPET) results and the full-length spinal X-rays in a standing position of 64 adolescents with idiopathic scoliosis were reviewed retrospectively. Independent t-tests were used to compare the two datasets obtained from those with left or right thoracic scoliosis. The correlation between the Cobb angle and cardiopulmonary exercise endurance was analyzed using Pearson correlation coefficients, multiple factor linear regression and two-stage linear regression.Results:After adjusting for gender, age, height and weight, the multiple linear regression analysis showed that the Cobb angle was significantly negatively correlated with maximum tidal volume (β=-0.013) and significantly positively correlated with the rate of respiration (β=0.421). The relationship between the Cobb angle and cardiopulmonary exercise endurance was non-linear. With a Cobb angle > 34°, a 1° increase reduces cardiopulmonary exercise endurance by a factor of 1.4 on average. At smaller Cobb angles the corresponding increase is about 0.87 times.Conclusions:The Cobb angle is a negative predictor of ventilation during exercise among adolescents with idiopathic scoliosis. The more severe a patient′s spinal curvature, the lower the cardiopulmonary exercise endurance is likely to be.
RESUMO
Objective · To provide theoretical guidance for the design of molecules with high activity by building the quantitative structure-activity relationship (QSAR) model for tropane compounds as muscarinic M3 receptor antagonists. Methods · Six compounds (J1-J6) were prepared with3α-hydroxy-tropane (J0) as the starting material by modifying the structure in C-3α position of the tropane skeleton. The antagonistic activity of new tropane compounds to muscarinic M3 receptors on tracheal rings of guinea pigs was evaluated by functional assays in vitro. The antagonistic parameters (pA2) of new tropane compounds prepared in this paper and former studies were applied to construct the QSAR model. The information about structural optimization was acquired by analyzing the effect of steric field and electrostatic field of model on activity of tropane compounds. Results · The six new tropane compounds showed obvious antagonistic activity against M3 receptors. Among them, J4 had the greatest activity (pA2=7.992). The cross-validation correlation coefficient squared (q2) and the non-cross-validated correlation coefficient squared (r2) of the QSAR model were 0.585 and 0.993, respectively.Conclusion · The antagonistic activity to muscarinic M3 receptors can be obviously improved, when the conjugating extent of π-bonds is large and O or N atoms participate in conjugation on the rings in the R-substituting group at C-3α position of the compounds.