ABSTRACT
BACKGROUND AND AIM: Available assays for measurement of pancreatic isoamylase in serum based on specific immunoinhibition of salivary fraction are unable to detect macroamylase. We combined a polyethylene glycol test which identifies macroamylase by selective precipitation with an automated assay for total amylase and pancreatic isoamylase measurement. METHODS: We analysed 24 sera proven positive for macroamylase using gel filtration chromatography and 80 negative sera. Precipitation of macroamylase with polyethylene glycol, colourimetric measurement of total amylase activity and immunoinhibition for the determination of pancreatic isoamylase were carried out. RESULTS: Macroamylasaemic sera showed precipitation of at least 71% of the amylase activity, while sera with normal-sized amylase exhibited a maximum of 61%. In all the macroamylasaemic sera but two, the immunoinhibition test showed a rise in pancreatic isoamylase, which was found to be the prevalent fraction in 16. In 21 out of 24 sera with macroamylase and 67 out of 80 with normal-sized amylase, the precipitated amylase activity was also measured after immunoinhibition of non pancreatic activity. In macroamylasaemic sera, the percentage of precipitated pancreatic isoamylase activity ranged from 75% to 98%, while in samples with normal-sized amylase it was less than 71%. CONCLUSIONS: Polyethylene glycol precipitation can easily be combined with automated assays for the determination of pancreatic isoamylase and should be carried out whenever dealing with hyperamylasaemia of unclear origin.
Subject(s)
Amylases/blood , Chemical Precipitation , Humans , Macromolecular Substances , Polyethylene Glycols , Reproducibility of Results , Solvents , Time FactorsSubject(s)
Chymotrypsin/metabolism , Feces/enzymology , Adolescent , Adult , Child , Child, Preschool , Female , Humans , Infant , Male , Middle Aged , Photometry , Reference ValuesABSTRACT
The paper reports the occurrence of myocardial infarctions in a patient with severe deficiency of blood coagulation factor XII (Hageman factor). Factor XII plays a central role in the intrinsic activation of fibrinolysis and consequently the defective intrinsic fibrinolytic activity detected in the present case casts some doubt on its role in the increased vulnerability to thrombotic accident.