采用Low Shear-30流变测定仪，改变人血红细胞压积（HCT），血浆浓度和正弦振荡剪切流频率，观察血液粘弹特性的变化。建立了经验方程，以表示HCT与粘性分量（η'），弹性分量（η"）的关系。

In order to demonstrate that IL-8 mRNA expression in endothelial cells is not only regulated by chemical factors, but also by mechanical factors, in this article, after pretreating cultured human umbilical vein endothelial cells (HUVECs) with shear stress for different time, we employed both RT-PCR to assay IL-8mRNA expression and immunocytochemical staining to detect NF-kB activation in HUVECs. We found that: (i) IL-8mRNA expressed little in HUVECs untreated or pretreated with low laminar shear stress for 0.5 hour; IL-8mRNA expression was increased when HUVECs were pretreated with low laminar shear stress for 1 hour, and increased further when pretreated for 2 hours; (ii) the immunoreactivity of NF-kB p65 in the nuclei of HUVECs untreated or pretreated with low laminar shear stress for 0.5 hour was negative, while it became weak positive in the nuclei of HUVECs pretreated with shear stress for 1 hour and positive in the nuclei of HUVECs pretreated for 2 hours. The results imply that low laminar shear stress was capable of inducing IL-8 gene expression and activating NF-kB, which were both time-dependent. The induction of IL-8 gene expression by laminar shear stress is probably due to the activation of NF-kB. We suggest that IL-8mRNA expression in endothelial cells induced by low shear stress may play a key role in the pathogenesis and development of both inflammation and arterioatherosclerosis.

The thixotroplc parameters of whole blood from 314 healthy subjects (154 women, 160 men) were measured with our modified method by Low shear 30 Rheometer and calculated according Huang's equation. This communication offered the reference range of thixotropic parameters from man and woman group. The results demonstrated that no significant differences existed in the plasma viscosity and fibrinogen between man and woman group. Man group had statistical-ly higher values in HCT, yield stress (to), Newtonlan contribution of viscosity (μ), non-Newtonian contribution of viscosity (ηs-μ), apparent viscosity at 2.37 sec-1 (ηs), the equi-librium value of the structual parameter (A) and apparent kinetic rate constant of rouleaux breakdown (ARC) than those in woman group. The man and woman groups could be sepa-rately divided into five subgroups in terms of age. It was found that the levels of fibrinogen and plasma viscosity had a tendency of increasing with aging. In the old subgroup (>60 years) of men and women HCT, to, ηs, μ, (ηs-μ) and A had significant lower values than those in young and middle-age subgroups. However, It was Very interested that there were differences of ARC versus age between man group and woman group, i.e. ARC in the man subgroup III, IV had lower and the woman subgroup I, III, IV had higher values than their respective older subgroup did.

The theological properties of whole human blood exhibit thixotropic behavior at low shear rates up to about ten reciprocal seconds (1). The accepted cause of this shear rate-dependent and time-dependent behavior is the progressive breakdown of rouleaux into individual red cells. Huang developed a theological e uation which incorporates the kinetics of rouleau breakdown in his models (2). This five-parameter e uation was used successfully to represent the hysteresis loop and the tor ue-decay curve of whole human blood. Numerical values of these five thixotropic parameters, which characterize the rheological behavior of the blood from apparently healthy human subjects, were established (3). In this communication, we examine the effect of hematocrit on each of the above mentioned parameters. The results show that the following parameters will increase their values with an increase in hematocrit: the yield stress, Newtonian contribution of viscosity, non-Newtonian contri-bution of viscosity, apparent viscosity and the e uilibrium value of the structural parameter which indicates the relative amount of rouleaux in blood. Mathematical e uations were developed to give the relationship between parameters and hematocrit. Two other thixotropic parameters, viz. the kinetic rate constant of rouleaux breakdown into individual red cells and the order of the breakdown reaction, were found to be independent of the hematocrit. It is consistent with reaction kinetic theory that the rate constant and the order of reaction are independent of the concentration of reactants.

血管内皮细胞位于血流和血管壁之间，除受化学因素的调节外还受力学因素的影响。切应力可通过刺激相应的力学感受系统来调节内皮细胞某些基因的表达，其中包括诱导内皮细胞表达IL-8。为了阐明MA PK信号途径中的ERK1/2 信号通路是否参与调控低切应力上调人脐静脉内皮细胞IL-8基因表达，采用Westernblot分析了低切应力（4.20 dyne/cm2）处理不同时间内皮细胞ERK1/2的磷酸化水平及TPK抑制剂Genistein,M EK抑制剂PD98059对其磷酸化的影响; 采用定量RT-PCR 检测内皮细胞经低切应力刺激或给予阻断剂后再行切应力刺激等处理后IL-8基因的表达。结果显示：（1）低切应力处理可引起内皮细胞ERK1/2蛋白磷酸化水平上调，其磷酸化水平与切应力作用时间有关，具有快速、双向性的特点（在刺激10min时达到高峰，2h左右降至未刺激水平），阻断剂Genistein和PD98059处理后，ERK1/2磷酸化水平与低切应力刺激10min比较明显降低；（2）阻断剂Genistein，PD98059可显著抑制低切应力所致的内皮细胞IL-8mRNA上调。结果表明低切应力可通过ERK1/2信号途径上调人脐静脉内皮细胞IL-8基因的表达。