Pancreatic Isoamylase Activity Research Articles

Can Serum Pancreatic Amylase and Lipase Levels Be Used as Diagnostic Markers to Distinguish Between Patients With Mucinous Cystic Lesions of the Pancreas, Chronic Pancreatitis, and Pancreatic Ductal Adenocarcinoma?

This study aimed to assess the presence of pancreatic hyperenzymemia in patients with pancreatic cystic lesions as compared to other chronic diseases of the pancreas. Ninety-one patients were studied: 32 had mucinous cystic lesions, 35 had chronic pancreatitis (CP), and 24 had pancreatic ductal adenocarcinoma (PDAC). Surgery was carried out in 10 of the 32 patients with mucinous cystic lesion (7 of them had severe dysplasia), in 5 patients with CP, and in 9 patients with PDAC. Abnormally high serum pancreatic isoamylase activity was present in 11 (34.4%) patients with mucinous cystic lesions, in 14 (40.0%) patients with CP, and none in patients with PDAC (P = 0.002); whereas serum lipase activity was abnormally high in 8 (25.0%) patients with mucinous cystic lesion, in 17 (48.6%) patients with CP, and in 3 (12.5%) patients with PDAC (P = 0.009). In 7 patients with mucinous cystic lesions and histologically confirmed severe dysplasia, abnormally high levels of both serum pancreatic amylase and lipase were present in 3 (42.9%) patients. High serum concentrations of pancreatic amylase and lipase were found in no more than half of the patients with mucinous cystic lesions. High levels of pancreatic enzymes were not associated with a greater risk of malignancy.

ISOLATED PANCREATIC AMYLASE DEFICIENCY-PROBABLE ERROR IN MOLECULAR BASIS

109 This study was to investigate further a 33 month-old Caucasian male found to have isolated amylase deficiency that appeared relevant to his failure-to-thrive. Secretin stimulated duodenal fluid collected at endoscopy at 20 months suggested isolated amylase deficiency (<3% of reference value), and normal pH, lipase ad proteases, that appeared to improve when repeated after catch-up weight gain on enzyme supplements to 3-10% of reference range. METHOD AND RESULTS: Serum pancreatic isoamylase activity measured by wheat germ enzyme inhibition was undetectable, but macroamylasemia, possibly suggesting disproportionate increase in salivary component was detected. Immuno-precipitation and Western blot analysis in the pancreatic fluid compared with positive and negative controls showed that the amylase activity was mainly from salivary isoenzyme and not pancreatic amylase at ages of 20 and 33 months, again suggesting compensatory salivary increase. Close homology to salivary isoform and multiple copies of genes made study of genomic DNA mutation difficult. We were able to isolate RNA from pancreatic fluid cellular debris to partly overcome these limitations. RT-PCR confirmed the presence of pancreatic amylase mRNA. cDNA sequences showed divergence in the amylase gene at 5′ end 927 bp coding region. Alignment with human pancreatic amylase revealed that most changes (7 out of 10 codon) were silent mutation, but Try67 to His, Cys118 to Ser and Thr178 to Val were significant. These three changes were located in the outer side of the core of activation domain of amylase. Combinations of these mutations however were documented in controls suggesting polymorphism. CONCLUSIONS: 1) apparent compensatory increase in salivary amylase was seen in duodenal fluid that can be misinterpreted as pancreatic isoform; 2) sequence divergence though probably from polymorphism could affect and lead to delay maturation; 3) method of isolation RNA from pancreatic fluid offers unique advantages in studying molecular basis of pancreatic enzyme deficiencies.

Influence of jejunal morphology changes on exocrine pancreatic function in celiac disease.

Concurrent exocrine pancreatic dysfunction may be one of the factors implicated in malabsorption in untreated celiac disease, as shown by studies on bicarbonate and pancreatic enzyme secretion. The purpose of this study was to evaluate exocrine pancreatic function in relation to jejunal morphology in celiac disease. Thirty-six patients fulfilling the ESPGHAN criteria for celiac disease, aged 3 to 18 years and 36 control subjects matched for age and sex were investigated. The design of the study included measurement of serum pancreatic isoamylase by a chromogenic method after selective inhibition of sialic isoamylase in the untreated phase in patients consuming a gluten-containing diet and after gluten elimination for a period of 1 year; fecal human elastase activity determined by enzyme-linked immunosorbent assay in patients consuming a gluten-free diet and again after gluten challenge for 6 months; correlation of serum pancreatic isoamylase and fecal elastase to the jejunal morphology, classified by criteria described by Marsch; the enzymes in the control group; and ultrasonography of the pancreas in both groups. Enzyme values obtained from celiac disease patients with normal mucosa were significantly higher than those obtained from patients with villous atrophy (p < 0.001) and comparable to those obtained from the control group. Serum pancreatic isoamylase activity increased to normal after gluten elimination, and human elastase activity decreased to values below 200 microg/g of stool after gluten challenge. Enzyme activity was related inversely to the degree of intestinal damage. The echogenicity of the pancreas was normal, regardless of enzyme activity or gut morphology. Exocrine pancreatic function is abnormal in celiac disease when mucosal atrophy is present. Exocrine pancreatic function parameters are associated with the changes of intestinal mucosal morphology in three consecutive phases of the disease.

FIFTEEN YEAR PROSPECTIVE STUDY OF PANCREATITIS IN A POPULATION OF PATIENTS WITH CYSTIC FIBROSIS

In Cystic Fibrosis (CF) pancreatic damage begins in utero. Pancreatic insufficiency (PI) is usually present at birth. In 15% of patients, the progression of pancreatic disease does not occur or is retarded. These patients are pancreatic sufficient (PS) and are susceptible to acute recurrent pancreatitis. The aim of this study is to investigate the frequency, natural history and outcome of pancreatitis in a CF population. Pancreatic function was assessed in 96 CF patients at diagnosis by measurement of serum pancreatic isoamylase activity (Phadebas PIA test, PIA normal values 40- 120 u/L). Fifteen CF patients (16%) who had pancreatic sufficiency (PS) (PIA 60-250 u/L) were followed up for episodes of pancreatic pain, evaluated with serial measurements of serum amylase, serum PIA and ultrasound of the pancreas. At the final phase, exocrine pancreatic function was monitored by serial fecal human pancreatic elastase (ELISA, Schebo-Tech, E1 normal values>200μg/gr stool). Clinical status was assessed by Schwachman score. Six of 15 patients with PS (40%) manifested recurrent, multiple episodes of acute pancreatic pain, marked elevation of pancreatic enzymes (PIA up to 2400 u/L) and evidence of pancreatitis on ultrasound. The episodes decreased gradually and serum PIA was stabilized at 60 to 90u/L. Gradual decline of fecal elastase to less than 200 (144, 170, 180) μg/gr stool was demonstrated in three while the remaining 12 PS patients had fecal elastase ranging from 257 to 2068μg/gr stool. Schwachman score in PS patients remained high throughout the observation period. It is concluded that acute recurrent pancreatitis occured in 6% of a CF population, exclusively in PS patients (40%). A subgroup of PS patients (20%) among those with recurrent pancreatitis developed PI and the need for pancreatic enzyme supplementation. Monitoring of exocrine pancreatic function in PS patients, especially in those with burnt out recurrent pancreatitis, is recommended.

Increased intrapancreatic trypsinogen activation in ischemia-induced experimental pancreatitis.

The potential of pancreatic ischemia to cause acute pancreatitis as indicated by morphologic changes and ectopic trypsinogen activation was investigated. Experimental evidence has shown that pancreatic ischemia is important in the evolution of severe pancreatitis, but whether ischemia can initiate pancreatitis has been disputed. Pancreatic ischemia was induced in rats by hemorrhagic hypotension (30 mm Hg for 30 min; n = 64). Changes of pancreatic microcirculatory perfusion were studied using diffuse reflectance spectroscopy. Serum amylase, trypsinogen activation peptide (TAP) in serum and pancreatic tissue, wet/dry weight ratio, and histology were determined over 24 hours and compared with sham-operated control subjects (n = 35). In control animals, serum amylase (47.9 +/- 2.1 units/L), serum (7.9 +/- 0.7 nmol/L) and tissue TAP (63.0 +/- 5.4 nmol/L x g), wet/dry weight ratio (2.8 +/- 0.1), and histology remained unchanged. Temporary hypotension markedly decreased pancreatic perfusion with incomplete recovery after reperfusion. Pancreatic isoamylase activity increased within 1 hour (110 +/- 5 units/L, p < 0.05) and further to 151 +/- 18 units/L at 24 hours. Tissue TAP was elevated at 1 hour (134 +/- 16 nmol/L x g, p < 0.05) and increased to 341 +/- 43 nmol/L x g (p < 0.001) after 24 hours, whereas serum TAP remained unchanged (8.3 +/- 0.5 nmol/L). Morphologic alterations included elevated wet/dry weight ratio (4.1 +/- 0.3, p < 0.01) and increased histologic scores for edema (p < 0.05) and acinar necrosis (p < 0.05) at 24 hours. Trypsinogen activation preceded the development of pancreatic necrosis. In addition to its potentiating role, severe pancreatic ischemia can play a pathogenetic role in the initiation of acute pancreatitis.

Total pancreatic and salivary serum iso-amylase activities in alcohol misusers in relapse and remission and in alcoholic liver disease

By means of immunoinhibition by specific salivary monoclonal antibodies in combination with a chromogenic substrate, assays of serum amylase were performed in control subjects, in chronic alcohol misusers in relapse or remission and in patients with alcoholic liver disease (ALD). There was a selective increase in the salivary isoenzyme in the ALD group. There were no significant changes in either of the alcohol misusing groups, compared with control subjects. It is suggested that the increase in salivary iso-amylase observed in patients with ALD is related to the previously reported functional and histological abnormalities in the parotid glands of this group of patients. It is also suggested that assay of pancreatic iso-amylase may be more discriminatory than total amylase levels in detecting pancreatic disease in patients with alcoholic cirrhosis.

Oxygen derived free radicals in patients with chronic pancreatic and other digestive diseases.

To ascertain modifications in the activation products derived from oxygen free radicals in patients with chronic pancreatic and extra-pancreatic diseases, lipid peroxide activity was measured in the sera of 40 control subjects, 28 patients with pancreatic cancer, 49 with chronic pancreatitis, and 53 with extra-pancreatic diseases. In 142 of the subjects, elastase 1, amylase, and pancreatic isoamylase activities were also determined. Increased lipid peroxide activities were found in some patients with both chronic pancreatic and extra-pancreatic diseases. Patients with chronic pancreatitis studied during relapse had higher activities of lipid peroxides than those without active disease. No difference was found between the values in patients with pancreatic cancer with liver metastases and those without. Correlations were found between lipid peroxides and both amylase and pancreatic isoamylase activities; no correlation was detected between lipid peroxides and elastase 1. In benign biliary tract disease a correlation was detected between lipid peroxides and alanine aminotransferase and alkaline phosphatase activities. In all patients, however, a correlation was found between alkaline phosphatase and lipid peroxide activities. It is concluded that activation of oxygen derived free radicals occurs in chronic pancreatic as well as in extra-pancreatic disease; it seems to reflect the degree of inflammation.

Diagnostic value of measuring pancreatic isoamylase with a double–monoclonal antibody immunoassay in serum of hospitalized hyperamylasemic patients

We evaluated the diagnostic utility of measuring pancreatic isoamylase (P-AMY) with a double-monoclonal antibody technique in a population of 43 consecutive hospitalized hyperamylasemic patients in comparison with serum pancreatic lipase (LPS) activity. In 27 cases (62.8%), the final diagnosis was acute pancreatitis. Predictive values were calculated for P-AMY and LPS activities, and a P-AMY percentage was calculated for selected decision levels. The maximal diagnostic efficiency was 0.930, 0.814, and 0.767 for LPS, P-AMY activity, and P-AMY percentage, respectively, indicating that serum LPS measurement was clinically superior to P-AMY for distinguishing patients with or without pancreatitis. Measurement of both P-AMY activity and percentage in serum did not significantly improve diagnostic accuracy.

Time-resolved immunofluorometric assay of human pancreatic isoamylase in serum, with use of two monoclonal antibodies.

This new method for determining pancreatic isoamylase (EC 3.2.1.1) in serum involves two monoclonal antibodies: one immobilized in a microtitration well (the capture antibody), the other biotinylated. After the sample is incubated with the two antibodies, the captured immunocomplex is quantified by adding streptavidin labeled with a europium chelator and measuring the specific Eu3+ fluorescence in a time-resolved mode. Three assay protocols are proposed, involving incubation times of 90, 45, or 25 min. The assay has low (0.005%) cross-reactivity with the salivary isoenzyme. Analytical performance was satisfactory. Results correlate well with results obtained by measuring total amylase activity or by measuring pancreatic isoamylase activity after immunoinhibition. Unlike numerous current amylase assays, this method measures enzyme mass rather than enzyme activity. Potentially, this is a highly specific assay.

Direct, rapid assay of pancreatic isoamylase activity by use of monoclonal antibodies with low affinity for macroamylasemic complexes.

Two Monoclonal Antibodies produced against Pancreatic Amylase have been produced and used to develop immunoassays (MAPA assays) for serum isoamylases. One antibody binds pancreatic isoamylase specifically and neither antibody inactivates amylolytic activity. MAPA assays that measure pancreatic and total enzymatic activities directly and rapidly in hyperamylasemic serum are described in this report. The influence of isoamylase determination on diagnosis is also investigated in 35 hyperamylasemic patients. The percentage for pancreatic amylase in serum as determined by immunoassay correlates well with results obtained by conventional electrophoresis (r = 0.90). Chart review indicates that use of MAPA assays would have potentially changed the diagnosis in 27% of patients. Five of six additional patients with hyperamylasemia caused by macroamylasemia had normal immunoreactive amylase values, and in all six patients the values were strikingly lower than predicted. The ability to assay organ-specific pancreatic isoamylase directly and early in the clinical course should reduce the risks of misdiagnosis and inappropriate therapy, especially in salivary-type hyperamylasemia or macroamylasemia.

Hyperamylasemia in Ethiopian Immigrants to Israel

Letters and Corrections1 June 1987Hyperamylasemia in Ethiopian Immigrants to IsraelDAVID HUMINER, M.D., SILVIO D. PITLIK, M.D.DAVID HUMINER, M.D.Search for more papers by this author, SILVIO D. PITLIK, M.D.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-106-6-910_1 SectionsAboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail ExcerptTo the editor: In 1985 we examined 13 newly arrived Ethiopian immigrants to Israel who were very ill on arrival. These patients came from a tropical area and most were affected by famine and had severe malnutrition and many infectious diseases(1).A striking laboratory finding was noted: 9 of the 13 patients had hyperamylasemia (greater than 324 U/L, Phadebas method) in blood samples taken shortly after refeeding. Six patients also had hyperamylasuria (less than 2000 U/L, Phadebas method). Isoenzyme analysis showed isolated elevation of pancreatic or salivary isoamylase activity in 3 patients, and of both isoenzymes in 2 other patients....

Panc reatic Enzymes in Chronic Renal Failure

Serum was obtained from 55 patients, including 43 with stable chronic renal failure (CRF) (28 receiving chronic hemodialysis [CHD] and 15 receiving chronic ambulatory peritoneal dialysis [CAPD]), nine with peritonitis receiving CAPD, and three with pancreatitis receiving CAPD. Total serum amylase activity, lipase activity, isoamylase fractionation, and lipase concentration were used to measure pancreatic enzymes. Amylase activity was increased in 35 of 43 patients with CRF but was greater than threefold elevated in only three. Pancreatic isoamylase activity was greater than 80% in only one patient with CRF but was greater than 80% in all three patients with pancreatitis receiving CAPD. Lipase activity was increased in 26 patients and lipase concentration was elevated in 27. Peritoneal fluid from three patients with pancreatitis receiving CAPD contained high levels of amylase. Serum amylase and lipase are frequently elevated in patients with CRF in the absence of clinical pancreatitis. However, serum amylase activity greater than threefold elevated or the presence of pancreatic enzymes in the peritoneal fluid may suggest coexistent pancreatitis.

Salivary amylase and pancreatic enzymes in Sjögren's syndrome.

Concentrations of immunoreactive trypsin (IRT) and pancreatic and salivary amylase activities were measured in 22 patients with primary Sjögren's syndrome (SS) and in 13 patients with secondary SS. Nineteen of the 22 patients with primary SS had above-normal IRT, and six had above-normal pancreatic isoamylase activity. Six of the 13 patients with secondary SS had above-normal IRT; none had above-normal isoamylase activities. Serum IRT and pancreatic isoamylase were correlated significantly (r = 0.7; p less than 0.0001). Above-normal values for IRT and pancreatic isoamylase were more frequent in patients who had SS for longer than 10 years, but were not related to the presence of salivary gland autoantibodies or to salivary isoamylase activity. We conclude that the concentration and activity of pancreatic enzymes are frequently abnormal in SS; that the abnormality is greater and more frequent in patients with primary SS; and that it increases with the duration of the disease.

Hyperamylasemia in Patients with Eating Disorders

Hyperamylasemia, which has been reported in patients with the eating disorders anorexia nervosa and bulimia, generally has been thought to result from pancreatitis. To evaluate the mechanisms of hyperamylasemia, we measured amylase, lipase, and isoamylase activity in 17 consecutive patients admitted to the eating disorder unit. Six patients had elevated amylase activity, and 5 of these 6 had isolated increases in salivary isoamylase activity. Six other patients had normal serum total amylase activity but modest elevations in the salivary isoamylase fraction. No patient developed clinical evidence of pancreatitis during hospitalization. Thus, the hyperamylasemia in patients with anorexia and bulimia often is caused by increased salivary-type amylase activity. The appropriate diagnostic test for hyperamylasemia in patients with anorexia or bulimia is the simple measurement of serum lipase or pancreatic isoamylase activity. If these levels are found to be normal, further tests to exclude pancreatitis are unnecessary.

Pancreatic disease in dyspepsia.

Determination of the serum activity of pancreatic isoamylase was performed in 30-65-year-old men seeking primary health care centers for dyspepsia. Of 36 consecutive patients 7 had abnormal pancreatic isoamylase activity in serum. This figure indicates dyspepsia to be commonly associated with pancreatic disease such as chronic pancreatitis.

Serum lipase, isoamylase and pancreatic function test (PFT) in juvenile-onset insulin-dependent diabetes mellitus.

Significantly decreased activity of pancreatic isoamylase in serum was found in a group of 51 juvenile-onset insulin-dependent diabetics as compared to healthy subjects (p less than 0.005). No significant changes were observed for urinary p-aminobenzoic acid excretion in 20 of the juvenile-onset diabetics in whom the NBT-PABA test was performed, even though 25% of the values were below the normal limit. A highly significant decrease of serum lipase activity was found in juvenile-onset diabetics as compared to controls (p less than 0.001). No significant correlation was found in juvenile-onset diabetics between serum pancreatic isoamylase and lipase or marker of chymotrypsin activity expressed as the amount of p-aminobenzoic acid excreted into urine. The NBT-PABA test appears to be of small importance in the evaluation of changes of the exocrine pancreas in insulin-dependent diabetes mellitus. However, simultaneous evaluation of serum pancreatic isoamylase and lipase activities justified the suspicion of pancreatic damage in 50% of the patients tested.

Kinetic measurement of total amylase and isoamylase activities with a centrifugal analyzer.

We evaluated a new kinetic assay for alpha-amylase (Phadebas IsoAmylase Test), using modified starch as the substrate and a CentrifiChem 400 centrifugal analyzer system. We determined isoamylase activities by using a selective inhibitor. Results were compared with those obtained with the chromogenic Phadebas dyed-starch technique. The method for total amylase appeared to be rapid and precise (CV = 4%) and results correlated well with the chromogenic method. Samples with activities up to 3000 arb. units/L can be analyzed without dilution. Glucose and pyruvate interfere with the assay, but hemoglobin and bilirubin do not. Pancreatic (P) and salivary (S) isoamylase activity can be determined with acceptable precision (CVP = 8%, CVS = 10%) by an automated routine procedure with commercially available reagents.

Ethnie ‘hyperamylasaemia’: clarification by isoamylase analysis

Total serum amylase and its pancreatic (P-type) and salivary (S-type) isoamylase activities were measured in 92 individuals without pancreatic or salivary disease. They were divided into three ethnic sub-groups resident in the UK, namely native Britons, Asians and West Indians. The mean total amylase activity was highest in West Indians (383 U/l), intermediate in Asians (317 U/l) and lowest in Britons (179 U/l). Nine of the 28 Asians and 8 of the 16 West Indians had total amylase activities above the upper end of the reference range for Britons. Such a finding, if accompanied by abdominal symptoms, could lead to exhaustive pancreatic investigation in these ethnic groups unless the appropriate reference range is used. Isoenzyme analysis by inhibitor and electrophoretic techniques indicated that the increase in total amylase was due to increase in S-type isoamylase, P-type isoamylase or both. There was a good correlation between results by the two methods. These differences in serum amylase seem to be genetically determined.

Two serum pancreatic isoamylase determinations compared.

Serum pancreatic isoamylase activity was measured by a method involving inhibition of salivary isoamylase and by a well-known agarose electrophoretic method, modified by us. We saw changes in electrophoretic patterns of pancreatic isoamylase fractions after storage of serum samples for three weeks at 4-8 degrees C, but with the inhibition method no alterations in activities were found. Within-assay and between-assay imprecisions of both methods were about the same. Serum pancreatic amylase activities as measured by the inhibition method exceeded by about 10% those obtained by the electrophoretic method. The inhibition method seems to be a reasonable candidate for routine application, whereas the electrophoretic method is still time-consuming and requires special skill to perform. Some suggestions are given for improving the calibration of the inhibition method recommended by the manufacturer.

Immunoreactive trypsin and pancreatic isoamylase activity in serum of patients with chronic renal failure or hepatic cirrhosis.

In 121 patients with either liver cirrhosis or chronic renal failure, abnormal values for the concentrations of two pancreatic enzymes in serum were a frequent finding. In renal insufficiency a decreased rate of enzyme elimination is the most likely cause of the above-normal values we observed for serum immunoreactive trypsin and pancreatic isoamylase activity. As for patients with liver cirrhosis, we believe that changes in entrance rates into the blood--i.e., an affected pancreas--is a likely explanation of the abnormally high values we often found for these serum enzymes.