A linear standard curve for determining amylase isoenzymes by selective inhibition.
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Amylases↗
Biomedical subjects
F J Hoek
Publications and source records attributed to F J Hoek.
Removal of bile acids from the blood by hemodialysis with a polyacrylonitril membrane: treatment of pruritus of cholestatic disease.
Hemodialysis with a polyacrylonitril membrane is evaluated as a possible method to alleviate pruritus accompanying severe prolonged cholestasis. To that extent results of a series of 30 dialysis sessions of a patient with advanced primary biliary cirrhosis are reported. Efficacy is measured with a pruritus score, kept by the patient herself, as well as with pre- and postdialysis plasma bile acid concentrations and bile acid concentrations in dialysates. Bile acid removal can then be calculated in three different ways: (a) From the decrease of the plasma bile acid concentration by dialysis a figure of 300 mumol bile acid removed is estimated. (b) Measurements of bile acid concentration in the dialysates results in a figure of 666 +/- (SD) 87 mumol bile acid removed. (c) From the mean pre- and postdialysis plasma bile acid concentrations together with an effective clearance rate of 8 ml/min for the bile acid mixture, calculated from ultrafiltration experiments, a removal of 589 +/- 100 mumol bile acid is calculated. These figures compare favorably with figures reported in the literature for the alternative techniques used, plasmapheresis and plasma perfusion over activated charcoal.
Acrylic Resins↗
[A new pancreas function test: the PABA test].
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4-Aminobenzoic Acid↗
In vitro and in vivo analysis of the PABA test compared with the Lundh test--influence of intraluminal pH.
Lundh test and PABA test results were compared in 50 patients. In the resulting correlation curve three areas of interest were differentiated: (1) an area with mean tryptic activity, found in the Lundh test, below 4 U/ml, where an abnormal PABA test result was also seen; (2) an intermediate area from 4 to 9 U/ml, where PABA test results may be found in discordance with the Lundh test; (3) the normal level, where PABA excretion was shown to be independent of intestinal chymotrypsin activity. In experiments in vitro on the kinetics of the hydrolysis of BTPABA by chymotrypsin the profound influence of the pH on Km and Vmax was shown. This influence of the pH explains why in the intermediate area of pancreatic dysfunction normal PABA test results were found in a number of cases. A higher mean pH level of the Lundh test aspirates was found for patients with a normal PABA test result than for patients with an abnormal PABA test.
4-Aminobenzoic Acid↗
Determination of uric acid with uricase and peroxidase.
A reliable method for the determination of uric acid in plasma or serum is described. The hydrogen peroxidase developed in the uricase reaction is used, together with peroxidase, for the coupling of sulphonated dichlorophenol and 4-aminoantipyine to a red dye. The difference in absorbance at 515 nm before and after addition of uricase is measured. Of the components tested for interference some gave rise to falsely lowered values. Reagents are cheap and the high molecular absorption coefficient of the red dye permits the use of small sample volumes.
Humans↗
Interference with the kinetic determination of acid phosphatase.
This study advocates cautious use of the kinetic determination method for acid phosphatase with alpha-naphthylphosphate as substrate and a diazonium salt for colour development. The occurrence of considerable blank rates due to the spontaneous hydrolysis of the substrate was noticed. Of the diazonium salts which were tested as alternatives for Fast Red TR, diazotised p-nitroaniline seemed to be useful. Also the interaction between plasma components and diazonium salts may influence the results of the determination. In this respect a number of possible interfering compounds was investigated and from these a structural element which may lead to side reactions was deduced.
Acid Phosphatase↗
Cholesterol nucleation-influencing activity in T-tube bile.
Nucleation-influencing activity was determined in T-tube bile samples derived from patients with obstructive jaundice. Since native T-tube bile samples do not nucleate, nucleation-influencing activity was determined by measuring the influence of T-tube bile on the nucleation time of model bile. In the assay, T-tube bile was mixed with model bile, and the nucleation time of this mixture was compared with the nucleation time of a model bile supplemented with the same amount of lipid as present in the bile sample. The results were expressed as ratio of the nucleation time of the mixture and the nucleation time of the control (NTm/NTc). There was a significant difference (p less than 0.01) between bile samples from patients with cholesterol gallstones and samples from patients with biliary obstruction due to other causes. More than 80% of the 33 samples from eight patients with stones were nucleation-promoting (NTm/NTc less than or equal to 0.6). Of the 40 bile samples from patients without stones, 7 were nucleation-promoting, 25 had no effect (NTm/NTc = 0.8 to 1.2) and 8 bile samples were nucleation-inhibiting (NTm/NTc greater than or equal to 1.4). There was no correlation between the lipid or protein content of a T-tube bile sample and its nucleation-influencing activity. The presence of both nucleation-promoting and nucleation-inhibiting activity in the same T-tube bile was demonstrated by chromatography on concanavalin A-Sepharose. More than 75% of the biliary protein did not bind to the column. This fraction showed nucleation-inhibiting activity.(ABSTRACT TRUNCATED AT 250 WORDS)
Bile↗