Analysis of effect of storage time and centrifugation speed on activity of biliary α-amylase

Abstract

Objective To study the effect of storage time and centrifugation speed on the activity of biliary α-amylase and the factors which affect the activity of α-amylase. Methods A total of 18 cases were randomly selected from 27 cases with endoscopic retrograde cholangiopancreatography in our hospital. The activity of biliary α-amylase was measured by iodine-starch colorimetry after bile samples were stored at 4℃ for 30 min, 3 h, 12 h, 24 h, 72 h and 30 d respectively, which was to study storage time in 6 groups each 18 cases. The bile samples in other 9 cases were used to study centrifugation speed including one group without sample centrifugation and the other two groups with sample centrifugation at 3 000 r/min or 8 000 r/min respectively. Results The activity of α- amylase decreased 0.73%, 2.11% and 3.94% in the bile stored at 4℃ for 3 h, 12~72 h or stored to 30 d respectively when compared with that stored 30 min (P>0.05), which indicated that the activity of biliary α-amylase did not change significantly for a period of storage 30 d at 4℃. The activity of biliary α- amylase decreased 0.16% after the centrifugation of 3 000 r/min compared with that without centrifugation, and increased 4.74% after the centrifugation of 8 000 r/min. The increase of 4.91% in the activity of biliary α-amylase was found at 8 000 r/min compared with that at 3 000 r/min(P>0.05), which indicated that the activity of biliary α-AMY had no obvious change when the centrifugal speed did not exceed 8 000 r/min. Conclusions The activity of biliary α-amylase would be relatively stable when bile is stored at 4℃ for 30 d and the centrifugal speed is 8 000 r/min or less.

Keywords

• |biliary α-amylase|storage time|centrifugation speed|stability|iodine-starch colorimetry