环孢素A对肾移植患者血清肝酶活性及总胆汁酸水平的影响

目的 :监测肾移植患者血清肝酶谷丙转氨酶 (ALT)、谷草转氨酶 (AST)、谷氨酰转肽酶 (r -GT)、碱性磷酸酶 (ALP)活性及总胆汁酸 (TBA)、总胆红素 (TBIL)水平的变化 ,了解环孢素A (CSA)的肝毒性作用。方法 :采用酶速率法、酶循环法及比色法 ,对 58例肾移植术后患者血清肝酶活性及总胆汁酸、总胆红素水平进行监测。结果 :移植术后早期 1～ 3个月内及半年左右 ,发生肝酶活性及总胆汁酸升高异常比例较高。结论 :药物的肝毒性在肾移植中应引起足够的重视 ,应及时监测肝酶活性及TBA水平 。

Measurement of serum paraoxonase-1 activity in the evaluation of liver function

Paraoxonase-1 (PON1) is an esterase and lactonase synthesized by the liver and found in the circulation associated with high-density lipoproteins. The physiological function of PON1 seems to be to degrade specific oxidized cholesteryl esters and oxidized phospholipids in lipoproteins and cell membranes. PON1 is, therefore, an antioxidant enzyme. Alterations in circulating PON1 levels have been reported in a variety of diseases involving oxidative stress including chronic liver diseases. Measurement of serum PON1 activity has been proposed as a potential test for the evaluation of liver function. However, this measurement is still restricted to research and has not been extensively applied in routine clinical chemistry laboratories. The reason for this restriction is due to the problem that the substrate commonly used for PON1 measurement, paraoxon, is toxic and unstable. The recent development of new assays with non-toxic substrates makes this proposal closer to a practical development. The present editorial summarizes PON1 biochemistry and function, its involvement with chronic liver impairment, and some aspects related to the measurement of PON1 activity in circulation.

Correlation of serum arylesterase activity on phenylacetate estimated by the integrated method to common classical biochemical indexes of liver damage

The correlation of serum arylesterase(PON1) activity on phenylacetate determined by an integrated method to clas-sical biochemical indexes of liver damage was investigated for the use of PON1 activity to evaluate liver damage.PON1 reaction curve as absorbance at 270 nm for 0.20 mmol/L phenylacetate hydrolysis was analyzed by the integrated method to determine maximal PON1 reaction rate.Classical biochemical indexes of liver damage were determined routinely.The 95% confidence threshold of PON1 activity in sera from healthy individuals was 2.12 mkat/L [(4.73±1.31) mkat/L,n=105].PON1 activity in clinical sera was closely correlated to serum albumin,total protein and the ratio of albumin to globulins,but was weakly correlated to both direct and total bilirubin in serum.There were no correlations of PON1 activity to γ-glutamyltransferase,alkaline phos-phatase,alanine aminotransferase and aspartate aminotransferase.Among 127 clinical sera with PON1 activity>2.12 mkat/L,there were 92% healthy individuals examined by albumin,90% healthy individuals examined by total protein,88% healthy individuals examined by total bilirubin,86% healthy individuals examined by direct bilirubin and 64% healthy individuals examined by the ratio of albumin to globulins,respectively.In each group of healthy individuals judged by classical biochemical indexes of close correlation to PON1 activity,percentage of healthy individuals examined by PON1 activity was always >80%.These results suggested PON1 activity on phenylacetate estimated by the integrated method was also suitable for the evaluation of liver damage.