Rypins E B, Sankary H, Wynn M J
Clin Chem. 1985 Sep;31(9):1557-9.
Data from first-order galactose clearance were used to estimate "effective" hepatic blood flow in normal subjects and in patients with hepatic diseases. Galactose clearance was determined by infusing galactose intravenously at a constant rate and measuring its resulting steady-state concentration in blood. The infusion rate must not exceed the maximum rate of galactose clearance by the liver, the "galactose elimination capacity." With this constraint and within the physiological and pathophysiological limits of hepatic blood flow, a constant infusion at 50 mg/min results in steady-state concentrations ranging from 20 to 200 mg/L. To measure galactose within this range, we modified a YSI Model 23A glucose analyzer and, using an immobilized galactose oxidase (EC 1.1.3.9)/hydrogen peroxide electrode system, accurately measured galactose in water and blood. The galactose metabolic clearance rate was calculated for six normal rats and for a normal and a cirrhotic human subject. The speed of the analysis (40 s), the small sample required (25 microL), and the suitability of fresh whole blood as the sample make the method ideal for measuring hepatic blood flow in small laboratory animals as well as for determining at bedside the effective hepatic blood flow in humans.
利用一级半乳糖清除率数据来估算正常受试者和肝病患者的“有效”肝血流量。半乳糖清除率是通过以恒定速率静脉输注半乳糖并测量其在血液中的稳态浓度来确定的。输注速率不得超过肝脏对半乳糖的最大清除率，即“半乳糖清除能力”。在这种限制条件下，以及在肝血流量的生理和病理生理限度内，以50mg/min的恒定输注速率会导致稳态浓度在20至200mg/L范围内。为了测量该范围内的半乳糖，我们对YSI 23A葡萄糖分析仪进行了改进，并使用固定化半乳糖氧化酶（EC 1.1.3.9）/过氧化氢电极系统，准确测量了水和血液中的半乳糖。计算了六只正常大鼠以及一名正常人和一名肝硬化患者的半乳糖代谢清除率。分析速度（40秒）、所需样本量小（25微升）以及新鲜全血作为样本的适用性，使得该方法非常适合测量小型实验动物的肝血流量，以及在床边测定人类的有效肝血流量。
