Evaluation of a new urinary amylase test strip in the diagnosis of acute pancreatitis.

We have developed a novel rapid test strip for detecting pancreatic amylase in urine and prospectively evaluated its accuracy in screening for acute pancreatitis (AP). The test strip is based on the immunochromatography principle and uses two monoclonal antibodies specific for pancreatic amylase. Urine samples were collected from 500 consecutive patients with acute abdominal disease (52 with AP) and prospectively tested with the strip. The accuracy of the test strip was compared with that of two quantitative urine amylase determinations and a urinary dipstick test for amylase (Rapignost). Sensitivity of the test was 69% and specificity was 97% in differentiating patients with AP from those with acute abdominal extrapancreatic disease at admission. The negative predictive value was 0.986. The test showed moderate agreement both with an assay measuring total amylase activity and with another measuring pancreatic amylase immunoreactivity. At similar high specificity (97%), quantitative determination of total amylase activity (cut-off 3960 U/L) and pancreatic amylase (cut-off 2180 micrograms/L) showed lower sensitivity (54% and 41%) than the test strip (69%). The test is specific and rapid to perform, and it rules out AP with high probability. It could therefore be useful in an emergency setting without laboratory facilities in the differential diagnosis of acute abdominal pain.

Hyperamylasemia after cardiac surgery in infants and children.

OBJECTIVE: This study was conducted to clarify the incidence of hyperamylasemia after cardiac surgery in infants and children. DESIGN AND PATIENTS: 186 infants and children operated on at Children's Hospital. Helsinki, during an 11-month period were enrolled in the study. Serum samples were taken before and on 3 consecutive days after cardiac surgery at the intensive care unit and before discharge from the hospital. MEASUREMENTS: We measured serum total amylase and serum pancreatic amylase with two different assays (1) reduction of salivary amylase from total amylase activity and (2) measurement of mass concentration with monoclonal antibodies. RESULTS: Preoperative values for both total amylase and pancreatic isoenzymes were strongly age-related. At least one of the three tests showed postoperative hyperamylasemia (> +/- 2 SD above starting values of the age group and maximal value > 3 times the individual starting value) in 64/186 (34%) patients. 22/186 (12%) patients had abnormal results in all assays. A more than tenfold rise in pancreatic amylase, suggesting pancreatitis, was found in 14 patients (8%). Mortality was 21% in this subgroup, but 5% in the rest of the patients. Hyperamylasemia was more common after 1 year of age, and after open-heart surgery, especially homograft implantation or cardiac transplantation. CONCLUSIONS: Hyperamylasemia is a common finding after cardiac surgery in pediatric patients. Amylase isoenzyme measurements are needed for clinical decision making. Age-group-related reference values are mandatory for the right interpretation of amylase values.

Immunocatalytic assay of pancreatic alpha-amylase in serum and urine with a specific monoclonal antibody.

In this immunocatalytic assay for alpha-amylase (EC 3.2.1.1) of pancreatic origin, a highly specific monoclonal antibody coupled to plastic beads is used to extract pancreatic amylase from samples, leaving salivary amylase in solution. The catalytic activity of the bound pancreatic amylase is then determined with blocked p-nitrophenyl maltoheptaoside as substrate. The method shows no cross-reactivity with salivary amylase, analytical recovery is 89-109% for pancreatic amylase, and interassay imprecision is 7.1-7.7%. We used the method to determine pancreatic amylase in serum and urine from healthy controls and different patient groups. The reference intervals for 34 supposedly healthy controls were: serum, 10-48 U/L (mean 27 U/L); urine, less than 20-435 U/L (mean 104 U/L). Results by the present assay correlated well with a salivary amylase inhibition assay (Boehringer Mannheim). We conclude that the described immunocatalytic assay is clinically useful for detecting increased activities of pancreatic amylase in serum and urine.

Gas-liquid chromatographic determination of mexiletine in human serum with nitrogen sensitive detection.

A simple and rapid method for the quantitative determination of mexiletine, using gas-liquid chromatography with nitrogen sensitive detection, is described. Only one extraction step is needed, the recovery is between 92-96% and the precision varies between 2.0--5.5%. The lower limit of detection reached 0.5 micro mol/1. During routine handling the method was easy, quick and cheap.

The hydration of phospholipids and phospholipid-cholesterol complexes.

The hydration characteristics of phosphatidylcholines and the effect of cholesterol on these were studied with differential thermal analysis and water vapour adsorption experiments. Also the water adsorption of egg phosphatidylethanolamine and the effect of cholesterol on this was studied and compared with corresponding qualities of phosphatidylcholine. The differential thermal analysis study showed that the monohydrates of egg, dipalmitoyl, and dioleoyl phosphatidylcholine tightly bind approximately 9 molecules of water per phosphatidylcholine molecule. Cholesterol is proved to somewhat increase the water binding of the phospholipids. Cholesterol is also shown to decrease the heat change of the chain melting transition of dioleoyl phosphatidylcholine, but not to abolish it completely. The water adsorption experiments indicate that the hydration of phosphatidylcholines takes place in two steps; a strong initial water binding and a second phase of weak binding. The adsorption isotherm of egg phosphatidylethanolamine is strikingly different from that of egg phosphatidylcholine. Cholesterol is shown, also by this method, to increase the hydration of phospholipids especially that of dipalmitoylphosphatidylcholine. The results in this study are in good agreement with those presented by many other authors. Starting with the accumulated information of the hydration characteristics of phosphatidylcholines the organization of the bound water around the polar group is discussed and the most probable model is evaluated.