Hua xi yi ke da xue xue bao = Journal of West China University of Medical Sciences = Huaxi yike daxue xuebao / [bian ji zhe, Hua xi yi ke da xue xue bao bian wei hui]
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Hua Xi Yi Ke Da Xue Xue Bao · Mar 1999
[On the problems of fitting linear regression models for hierarchically structured data in medical research].
There are a large number of the hierarchically structured data in the field of medical sciences, which have been analyzed usually by conventional linear regression models. The objective of this paper is to explore the problems and the relationship of parameter estimates of the three common linear regression models in fitting the hierarchically structured date, and the correction of the precision of parameter estimates. It is shown that the estimate of parameter and it's precision of linear regression models is related to the variation of independent variable between and within level 2 units, and the difference of residual estimates is associated with the difference of parameter estimates. The three common linear regression models are all inappropriate for the hierarchically structured data, but the standard error of the level 1 combined model can be corrected by variance inflation factor in conditions.
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Hua Xi Yi Ke Da Xue Xue Bao · Mar 1999
[Leukocyte adhesion molecule expression and circulating ICAM-1, E-selectin levels during cardiopulmonary bypass in patients undergoing valve replacement].
The objectives of this study were to measure leukocyte adhesion molecule expression, assess the possibility of evaluating the serum levels of the soluble form of endothelium adhesion molecule as an alternative for endothelia cell activation, and analyze the correlation and regression between leukocyte adhesion molecule expression and soluble endothelium adhesion molecule levels during cardiopulmonary bypass (CPB) in patients undergoing valve replacement. Twelve adult patients were included in this study. The extracorporeal circuit was primed with Ringer's lactate. ⋯ Upregulation of the leukocyte adhesion molecule expression and increase of the circulation endothelium adhesion molecule levels lasted at least 2 days after surgery (P < 0.05) except CD11a. There were correlation and regression between leukocyte adhesion molecule expression and soluble endothelium adhesion molecule levels (r = 0.91-0.99, P = 0.0322-0.0005; Y = -1377.06-44.64 + 1.49-14.78a to Y = 44.64 + 1.49a). These results suggest that CPB causes obvious leukocyte-endothelia interactions, that the expression of these adhesion molecules are presented by means of receptor-ligand form, and that the measurement of sICAM-1 and sE-selectin may well be used as a marker of endothelial cell activation.