Document Detail


Lipase activity measured in serum by a continuous-monitoring pH-Stat technique--an update.
MedLine Citation:
PMID:  2758637     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Using recent knowledge regarding the roles of colipase, bile acids, Ca2+, and emulsifiers, we optimized a previously published pH-Stat method for lipase (EC 3.1.1.3) activity measurements. The recommended assay conditions are: olive oil/triolein, 100 mL/L; sodium glycocholate, 35 mmol/L; Ca2+, 8.5 mmol/L; and colipase, 6.0 mg/L. The sample volume is 0.10 mL, the reaction pH 9.0, the temperature 30 degrees C, and the concentration of titrant 15 mmol/L. Hydroxypropyl methylcellulose, 20 g/L, replaces acacia as emulsifier to avoid inhibition by excess Ca2+. The standard curve is linear to greater than 4566 U/L. The reference interval with olive oil as substrate is 30-235 U/L. Lipase activities with triolein substrate are 9.9% greater than with olive oil. Interference by pancreatic carboxylesterase (EC 3.1.1.1) activity is inhibited by incubating the sample with diisopropylfluorophosphate. Results correlate well with those by the optimized SingleVial method of Boehringer Mannheim Diagnostics (r = 0.997) and the immunochemical assay of Beckman Instruments, Inc. (r = 0.995). Correlation with the aca method (E.I. DuPont de Nemours & Company) is less satisfactory (r = 0.892), probably owing to lack of colipase in the latter method.
Authors:
N W Tietz; J R Astles; D F Shuey
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Clinical chemistry     Volume:  35     ISSN:  0009-9147     ISO Abbreviation:  Clin. Chem.     Publication Date:  1989 Aug 
Date Detail:
Created Date:  1989-09-13     Completed Date:  1989-09-13     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9421549     Medline TA:  Clin Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1688-93     Citation Subset:  IM    
Affiliation:
Department of Pathology, University of Kentucky Medical Center, Lexington.
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MeSH Terms
Descriptor/Qualifier:
Adult
Autoanalysis
Calcium / pharmacology
Carboxylesterase
Carboxylic Ester Hydrolases / antagonists & inhibitors
Colipases
Glycocholic Acid
Humans
Hydrogen-Ion Concentration
Lipase / blood*
Plant Oils
Sodium Chloride / pharmacology
Triolein
Chemical
Reg. No./Substance:
0/Colipases; 0/Plant Oils; 122-32-7/Triolein; 475-31-0/Glycocholic Acid; 7440-70-2/Calcium; 7647-14-5/Sodium Chloride; 8001-25-0/olive oil; EC 3.1.1.-/Carboxylic Ester Hydrolases; EC 3.1.1.1/Carboxylesterase; EC 3.1.1.3/Lipase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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