Few of paperon alteration in thixotroplc properties of blood from patients with cerebral vascular diseases has been found yet. With Low Shear 30 rheometer, we modified the measuring protocol according to Huang's equation and determined the thixotroplc parameters of whole blood from 72 male patients with cerebral vascular diseases, thus we compared these parameters with those of blood from healthy subjects matched in sex and age. The results demonstrated that the yield stress, non-Newtonian contribution of viscosity',apparent viscosity (2.37 s-1) and the equilibrium value of structure parameters in the patients with cerebral arteriosclerosis (CA, n=14), transient cerebral ischemic attack (TIA, n=12) and cerebral thrombosis (n=46) were significantly higher than those of corresponding control groups. However, there were no significant changes In hematoerit, Newtonian contribution of viscosity and apparent kinetic rate constant of rouleaux breakdown. No significant differences of the thixotropic parameters existed among groups of CA, TIA and cerebral thrombosis. The results suggest that the patients with cerebral vascular diseases had evidently increased the amount and degree of RBC aggregation. Further more, before onset of cerebral thrombosis the patients with CA and TIA had already obvious change in thixotropy of blood. This probably implies that abnormality of thixotropy of blood is not a trigger factor for ischemic stroke, but a possible subsidiary or an associated risk factors.

In order to study the role of hemorheology in pathogenesis of acute hemorrhagic necrotizing pancreatitis (AHNP), forty four adult hybrid dogs were used and divided into 5 groups. Groups I and II were operation control (8 dogs) and acute interstitial pancreatitis group (8 dogs) respectively. Groups III-V suffered from AHNP by injection of sodium taurocholate in major pancreatic duct. Furthernore, groups IV and V were treated with Dextran 40 solution and Salvia Miltiorrhizae intravenous injection respectively. Arterial blood pressure and central venous pressure in all 5 groups did not exhibit significant changes before and after operation. Serum amylase and ]ipase level of groups III-V increased obviously after AHHP, but they decreased more rapidly in groups IV and V after treatment with drug than those in group III. Henorheologic changes were measured with Low Shear 30 sinus. Plasma viscosity of all 5 groups had no evident changes before and after operation. There were no significant changes in henatocrit (HCT), apparent viscosities of whole blood at 0.512 sec-1 (η0.512) and 51.2 see-1 (751.2), aggregation index of RBC (AI), viscous component (η') and elastic component (η") of complex viscosity; and elastic molulus (G') of whole blood in groups I and II had no significant alteration before and after operation. However, the parameters mentioned above in groups III-V increased significantly after AHNP had been induced by experiment. They decreased continuously after treatment with drug in groups IV and V. However, Salvia Miltiorrhizae injection in group V had better improvement in henorheological alteration than DX40 in group IV did. The results suggested that abnornality of hemorheology was an important factor to introduce the disturbance of nicrocirculation of pancreas during AHNP and correction of henorheological abnoruality could improve symptons of pancreatitis.

We studied hemor-heologic alterations in acute pancreatitis in 2g dogs to find out that during the early stage of induction of acute necrotizing pancrea-tiffs, all the hemorheologic parameters were signifi-cantly elevated, and continued to increase at the restintervals but no difference between the acute in-terstitial pancreatitis and control groups. We suggest that increased blood viscosity and tendency of ery-throeytes to aggregate with rouleaux formation are the causes of microeirculatory thrombosis in pan-creas. They may be th key factors in the patbo. genesis of pancreatic necrosis in acute necrotizing pancreatitis.

The steady state non-Newtonian viscosity of whole human blood has been widely studied as a function of the shear rate; and used to characterize the blood in various pathological disorders. In our previous studies, we demonstrated that blood is a thixotropic fluid. Its time-dependency and shear rate dependency of rheological behavior can be represented by an equation developed by Huang. Parameters of the equation can be used for the characterization of an individual's blood. They provide information, such as the kinetic rate constant of breakdown of RBC rouleaux to individual erythrocytes and the relative amount of rouleau formation in the dynamic equilibrium between rouleaux and individual erythrocytes. In this communication, the thixotropic parameters from blood samples of fifteen apparently healthy human subjects were investigated. When compared to the use of apparent viscosity values for the correlation with a pathological disorder, thixotropic parameters are preferable. The mean values of thixotropic parameters obtained from apparently healthy human subjects provide a base for comparison with the same parameters as obtained from blood samples of patients with certain pathological disorders involving the circulation.