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阿滋海默症血液流變學的研究 血液流變學的研究在臨床醫學應用之發展上具有舉足輕重的影響。近年來阿滋海默症病患體內微循環障礙的病理徵象，漸為臨床醫師所重視。本研究主要以血液流變學(Hemorheology)模式評估阿滋海默症(Alzheimer’s disease)老人各項血液流變參數的異常，並討論血液流變參數異常的機制及其對於阿滋海默症老人體內微循環的影響。研究對象以 6位阿滋海默症老人為實驗組及10位年齡與實驗組相近的正常老人為對照組。兩組受測者以簡易智能狀態測驗(MMSE ; Minimurn Mental State Examination)以評估患者認知功能。經空腹採血進行血液各項生化、血球及血液流變參數檢測。分別於低、中及高剪切率下檢測全血黏度(Whole Blood Viscosity)，震盪流中檢測黏彈性(Blood Viscoelasticity)，低剪切率下測定紅血球聚集度(Erythrocyte Aggregation)，高剪切率下檢測紅血球變形度(Erythrocyte Deformability)及血漿黏度(Plasma Viscosity)，及利用Dintenfass所提之公式{Tk= [(ηr0.4-1)/ηr0.4 ] / Hct}計算出紅血球內黏度(Tk Level )。實驗結果顯示，阿滋海默症老人血液流變各項參數，從巨觀之血液黏度至微觀之紅血球變形度皆顯著異常於正常老人。其中阿滋海默症老人之血液黏度、血漿黏度、血漿纖維蛋白原、血液黏彈性及紅血球聚集度皆明顯高於正常老人，而紅血球變形度則明顯低於正常老人。然而紅血球容積比與紅血球內黏度並無明顯差異。而引起阿滋海默症老人血液中紅血球於低剪切率下表現出高聚集性，使血液黏度增高，其主因為血漿中纖維蛋白原增高。於高剪切率下表現出低變形度，使血液黏度增加則主因於紅血球膜性質的改變之故。
Hemrheological changes in patients with Alzheimer''s disease • Hemorheological studies were very important in the clinical development. Recently,microvascular abnormalities in Alzheimer’s disease is under intensive investigated.This study to evaluate the changes in hemorheological indexes for patients with Alzheimer’s disease and to discuss the mechanism of these changes and the effects in patients with Alzheimer’s disease.Six elderly patients with Alzheimer’s disease and ten age-matched healthy subjects were included by evaluating the cognitive function of the Minimum Mental State Examination test (MMSE) . Fasting blood samples were collected to measure the biochemistries, complete blood counts and hemorheological indexes. Whole blood viscosity was measured in low, middle and high shear rate. Blood viscoelasticity was measured in oscillated model, Moreover,erythrocyte aggregation was measured in low shear rate.And plasma viscosity and erythrocyte deformability were measured in high shear. “Tk”level was calculated according to the equation {Tk= [(ηr0.4-1)/ηr0.4 ] / Hct } of Dintenfass.The result revealed that there were significant different in all hemorheological indexes between Alzheimer’s disease group and control group except Hct and Tk level. Whole blood viscosity, plasma viscosity, viscoelasticity, plasma fibrinogen and erythrocyte aggregation of patients with Alzheimer’s disease group were significant higher than those of normal control group.Erythrocyte deformability of patients with Alzheimer’s disease was significant lower than healthy subjects. The increased erythrocyte aggregation duing low shear rate may due to the increased fibrinogen concentration.The decreased erythrocyte de- formability during high shear rate may result from membrane modification of erythrocyte.
