Characteristic alterations of serum isoenzymes of amylase in diseases of liver, pancreas, salivary gland, lung, and genitalia

Hyperamylasemia as an Early Predictor of Mortality in Patients with Acute Paraquat Poisoning

Background

Paraquat (PQ) is a non-selective and fast-acting contact herbicide which has been widely used in developing countries. Hyperamylasemia was reported in patients with PQ poisoning. This study investigated the predictive value and clinical characteristics of hyperamylasemia in patients with PQ poisoning.

Material/Methods

This study included 87 patients with acute PQ poisoning admitted from July 2012 to May 2015. Data were collected from medical records. Receiver operating characteristic (ROC) analysis was conducted to analyze the discriminatory potential of serum amylase with respect to 90-day mortality.

Results

Of 87 patients, 29 patients had elevated serum amylase. We found that serum amylase was significantly higher among patients with AKI than those with non-AKI (p<0.001), and was an independent predictor of mortality (hazard ratio [HR]=3.644; 95% [CI], 1.684–7.881; p=0.001). The area under the ROC curve for the serum amylase (area under curve [AUC]=0.796; 95% [CI], 0.690–0.903) had a better discriminatory potential than plasma PQ concentration (0.698;0.570–0.825) or urinary PQ concentration (0.647;0.514–0.781) in predicting 90-day mortality.

Conclusions

Hyperamylasemia is a valuable early predictor of 90-day mortality in PQ poisoning.

Etiology and diagnosis of acute biliary pancreatitis

Establishing a biliary etiology in acute pancreatitis is clinically important because of the potential need for invasive treatment, such as endoscopic retrograde cholangiopancreatography. The etiology of acute biliary pancreatitis (ABP) is multifactorial and complex. Passage of small gallbladder stones or biliary sludge through the ampulla of Vater seems to be important in the pathogenesis of ABP. Other factors, such as anatomical variations associated with an increased biliopancreatic reflux, bile and pancreatic juice exclusion from the duodenum, and genetic factors might contribute to the development of ABP. A diagnosis of a biliary etiology in acute pancreatitis is supported by both laboratory and imaging investigations. An increased serum level of alanine aminotransferase (>1.0 microkat/l) is associated with a high probability of gallstone pancreatitis (positive predictive value 80-90%). Confirmation of choledocholithiasis is most accurately obtained using endoscopic ultrasonography or magnetic resonance cholangiopancreatography. This Review discusses the pathogenesis of ABP and the clinical techniques used to predict and establish a biliary origin in patients with suspected ABP.

Pancreatic cellular injury after cardiac surgery with cardiopulmonary bypass: frequency, time course and risk factors

Although often clinically silent, pancreatic cellular injury (PCI) is relatively frequent after cardiac surgery with cardiopulmonary bypass; and its etiology and time course are largely unknown. We defined PCI as the simultaneous presence of abnormal values of pancreatic isoamylase and immunoreactive trypsin (IRT). The frequency and time evolution of PCI were assessed in this condition using assays for specific exocrine pancreatic enzymes. Correlations with inflammatory markers were searched for preoperative risk factors. One hundred ninety-three patients submitted to cardiac surgery were enrolled prospectively. Blood IRT, amylase, pancreatic isoamylase, lipase, and markers of inflammation (alpha1-protease inhibitor, alpha2-macroglobulin, myeloperoxidase) were measured preoperatively and postoperatively until day 8. The postoperative increase in plasma levels of pancreatic enzymes and urinary IRT was biphasic in all patients: early after surgery and later (from day 4 to 8 after surgery). One hundred thirty-three patients (69%) experienced PCI, with mean IRT, isoamylase, and alpha1-protease inhibitor values higher for each sample than that in patients without PCI. By multiple regression analysis, we found preoperative values of plasma IRT >or=40 ng/mL, amylase >or=42 IU/mL, and pancreatic isoamylase >or=20 IU/L associated with a higher incidence of postsurgery PCI (P < 0.005). In the PCI patients, a significant correlation was found between the 4 pancreatic enzymes and urinary IRT, total calcium, myeloperoxidase, alpha1-protease inhibitor, and alpha2-macroglobulin. These data support a high prevalence of postoperative PCI after cardiac surgery with cardiopulmonary bypass, typically biphasic and clinically silent, especially when pancreatic enzymes were elevated preoperatively.

Hyperamylasemia in bulimia nervosa and hyperemesis gravidarum

OBJECTIVES

The exact causes of hyperamylasemia detected in bulimia nervosa are unknown but it is presumed to be due either to repeated binging or to vomiting. This study set out to investigate the importance of vomiting in producing the raised serum amylase and to clarify whether the amylase in pancreatic or salivary.

METHODS

Patients suffering from hyperemesis gravidarum who were repeatedly vomiting in pregnancy but not binge eating had their total serum and pancreatic amylase measured. Bulimic patients and a control sample of nonvomiting pregnant women were similarly studied. An assessment of the frequency and duration of vomiting and binging was also made.

RESULTS

Results show 45% (5) of bulimic patients had raised serum amylase, but none had a raised pancreatic amylase. Twenty-four percent (7) of the hyperemetic patients also had a raised serum amylase level, all with a normal pancreatic amylase level. None of the nonvomiting pregnant patients had a raised amylase.

DISCUSSION

Of patients with hyperemesis gravidarum who repeatedly vomit but do not binge, a significant number had raised amylase. This suggests that it is the vomiting rather than the binge behavior that increases amylase in bulimic patients. This increased amylase probably comes from the salivary gland.

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.

Postburn pancreatitis

OBJECTIVE

The authors examined the prevalence and complications of pancreatitis in severely burned patients. Factors predictive for the development of pancreatitis after burns are considered.

SUMMARY BACKGROUND DATA

Pancreatitis has been documented at necropsy after burns; however, it is not clinically recognized as a common complication of burn injury. Recent improvements in survival rates could yield previously unrecognized complications, such as pancreatitis, particularly in those patients who previously would have not survived. The hypothesis is that pancreatitis is a frequent complication after major burn injury and causes significant morbidity for patients with large burns.

METHODS

This retrospective review of adult patients with large burns examines postburn pancreatitis using stepwise logistic regression analysis.

RESULTS

Forty-nine of 121 (40%) patients developed hyperamylasemia or hyperlipasemia well after the admission period (23 +/- 3 days), and all enzyme abnormalities were temporally associated with emerging infections. Most of these patients (40/49, 82%) had symptoms of pancreatitis. Three patients (6%) had pancreatic pseudocysts or abscesses. Inhalation injury (p = 0.0001), associated trauma (p = 0.0311), and escharotomy (p = 0.0415) were risk factors for pancreatitis. Using Fischer's exact test, patients with pancreatitis had increased mortality and length of stay. Patients with high enzyme elevations and > or = 50% body surface area burned were at severe risk of pancreatic pseudocyst or abscess development (43%; 90% confidence interval of 23-77%).

CONCLUSIONS

Pancreatitis is a frequent complication after large burn injuries. Patients at high risk for pancreatitis complications should receive surveillance examinations during their acute hospitalization.

The role of serum amylase in the diagnosis of acute pelvic inflammatory disease

The use of serum amylase levels in the diagnosis of acute pelvic inflammatory disease (PID) was investigated prospectively. Eighty-five women presenting with the chief complaint of lower abdominal pain were entered into the study; all patients were examined by one of the principal investigators. In addition to the usual laboratory studies, a serum amylase level was obtained on all patients; the investigators were blinded to the results. Patients were diagnosed with PID if they fulfilled previously published clinical criteria. Forty-eight patients met the criteria for the diagnosis of PID (PID group); 37 patients were diagnosed with other disease processes (non-PID group). The average serum amylase level for the PID group was 62 U/L, with a standard deviation (STD) of 24; for the non-PID group, the average was 76 U/L with an STD of 32. Although there was a statistical difference between the two groups (P < .05), there was no clinically significant difference because both values fell within the normal range of serum amylase. The routine use of serum amylase in the diagnosis of acute PID seems to be of no value.

A prospective study of amylase-rich pleural effusions with special reference to amylase isoenzyme analysis

By analysis of pleural effusions from 200 patients, 25 cases of amylase-rich effusions were identified, for an overall incidence of 13 percent. Four of the 25 patients (16 percent) had evidence of pancreatitis. These patients had higher mean ratios of pleural fluid to serum amylase levels (18 +/- 6.3 [SEM] vs 4.8 +/- 1.3) compared to patients with nonpancreatic diseases (p = 0.003); all four exhibited a predominant pancreatic isoenzyme profile. Of the 21 patients with nonpancreatic amylase-rich effusions, lung cancer was the most commonly associated condition (8 patients). In 14 of the 21 patients in whom an isoenzyme profile was obtained, salivary-type amylase was predominant. Amylase-rich pleural effusions occur frequently, and pleural fluid isoamylase determination is specific for pancreatitis-associated effusions. The finding of a pleural effusion rich in salivary isoamylase should prompt an evaluation for carcinoma (particularly of lung primary), but may also be seen in other pleural inflammatory conditions.

Risk factors for pancreatic cellular injury after cardiopulmonary bypass

BACKGROUND

Pancreatitis is a known complication of cardiac surgery with cardiopulmonary bypass. Although ischemia is believed to be a factor, the cause of pancreatitis after cardiopulmonary bypass remains unknown.

METHODS

We prospectively studied 300 consecutive patients undergoing cardiac surgery with cardiopulmonary bypass. Serum amylase, pancreatic isoamylase, and serum lipase were measured on postoperative days 1,2,3,7, and 10. Pancreatic cellular injury was defined as the presence of hyperamylasemia (greater than 123 U per liter) with an increase in either the serum level of lipase (greater than 24 U per liter) or the peak level of pancreatic isoamylase. Trypsinogen-activation peptides, which indicate intrapancreatic enzyme activation, were measured in the urine of the last 101 patients studied.

RESULTS

Evidence of pancreatic cellular injury was detected in 80 patients (27 percent), of whom 23 had associated abdominal signs or symptoms and 3 had severe pancreatitis (2 with pancreatic abscess and 1 with necrotizing hemorrhagic pancreatitis). Two of 19 postoperative deaths were secondary to pancreatitis. In multivariate analyses, the development of pancreatic cellular injury was significantly associated with preoperative renal insufficiency, valve surgery, postoperative hypotension, and perioperative administration of calcium chloride. The administration of more than 800 mg of calcium chloride per square meter of body-surface area was an independent predictor of pancreatic cellular injury, and the increase in risk was dose-related. No differences were found in the level of trypsinogen-activation peptides between patients who had pancreatic cellular injury and those who did not.

CONCLUSIONS

Pancreatic cellular injury, as indicated by hyperamylasemia of pancreatic origin, is common after cardiac surgery. The administration of large doses of calcium chloride is an independent predictor of pancreatic cellular injury and may be a cause of it.

Serum amylase of non-parotid and non-pancreatic origin increases on feeding in rats and may originate from the liver

1. In order to evaluate possible non-salivary contributions to the content of salivary-type amylase in the circulation, parotid glands--the only salivary source of amylase in rats--have been totally removed and the effects on serum amylase have been assessed, after fasting and at different times after feeding. 2. Despite the parotidectomy the resting level of salivary-type amylase remained the same and an increase was still found to occur on feeding. 3. Isoelectric focusing has identified additional isoforms of amylase in serum and liver distinct from those occurring in parotid saliva. 4. The liver therefore may be contributing to the fasting levels of serum amylase and to the increases that occur on feeding, in rats.

Hyperamylasemia after cardiac surgery. Incidence, significance, and management

The significance of hyperamylasemia and its relationship to pancreatitis after cardiac surgery is controversial. Three hundred consecutive patients undergoing cardiopulmonary bypass were prospectively studied to determine the incidence and significance of postoperative hyperamylasemia. Ninety-six of three hundred patients (32%) developed hyperamylasemia. Fifty-six patients (19%) were classified as having isolated hyperamylasemia because they were asymptomatic and had normal serum lipase. Thirty-two patients (10.7%) had subclinical pancreatitis defined as elevation of serum amylase and lipase or pancreatic isoamylase. Many of these patients had mild gastrointestinal symptoms that were self-limited. Eight patients (2.7%) had overt pancreatitis documented by clinical findings, biochemical abnormalities, and computed tomography (CT) scan or autopsy. Isoamylase analysis demonstrated that isolated hyperamylasemia usually originated from nonpancreatic sources. However, hyperamylasemia occurring in conjunction with abdominal signs and symptoms or elevated serum lipase was almost always pancreatic in origin. Patients with hyperamylasemia had a significantly higher mortality rate (seven of 96 patients, 7.5%) than those with normal serum amylase (two of 204 patients, 0.9%) (p less than 0.01) even when the amylase was nonpancreatic in origin (five of 56 patients, 9%). The reason that nonpancreatic hyperamylasemia is associated with increased postoperative mortality is not established but may represent a variety of metabolic aberrations or tissue injuries. It is concluded that 1) hyperamylasemia after cardiopulmonary bypass is a marker of potential clinical importance, and 2) pancreatitis in this setting is more common than previously recognized and is a potentially lethal complications. Successful treatment depends on early diagnosis and aggressive treatment.

Serum amylase levels in ectopic pregnancy

Thirty-four women with abdominal complaints and a positive pregnancy test were evaluated for possible ectopic pregnancy (EP). Serum amylase levels were obtained as part of the diagnostic workup to note any correlation of enzyme levels with the presence of EP. Thirteen individuals (30%) were subsequently diagnosed as having an EP, and serum amylase levels in all of these patients were within normal limits, averaging 81 U/L. There was no statistically significant difference in amylase levels between the EP group and the non-EP group (P = .70). Serum amylase levels cannot reliably predict the presence of EP and should not be used as a screening or diagnostic test for this disorder.

Immunohistochemical and immunoelectron microscopic study of an amylase-producing, CA19-9 positive ovarian mucinous cystadenocarcinoma

A 75-year-old woman with a right ovarian tumor revealed high levels of serum amylase and CA19-9 which decreased to within normal limits after the operation. A histopathological study of surgically excised tumor tissue revealed a mucinous cystadenocarcinoma. The tumor was composed of three elements: adenoma, adenoma with low potential malignancy, and adenocarcinoma. Using the light microscopic indirect immunoperoxidase technique for amylase and CEA, and the Avidin-Biotin affinity technique for CA19-9 and CA12-5, the amylase and CA19-9 were stained in the cytoplasm of the adenoma and adenocarcinoma although CEA was stained only in the cytoplasm of the adenocarcinoma. An ultrastructural study using the immunoperoxidase method revealed that CA19-9 was positive in the apical portion of the tumor cells and amylase was positive in the entire secretory vesicles of the tumor cells. Furthermore, ciliated tumor cells derived from fallopian tube epithelium were not observed in the light and electron microscopic specimens.

Frequency of pancreatitis in fulminant hepatic failure using isoenzyme markers

Evidence of acute pancreatitis was sought in 35 patients with fulminant hepatic failure. Total amylase was raised in 22 patients and isoenzyme separation showed a distinct P3 isoenzyme (indicative of pancreatitis) in 14. In four patients with marked hyperamylasaemia (greater than 1000 U/l) the predominant isoenzyme was the salivary fraction. Pancreatic lipase was abnormally raised (greater than 200 U/l) in 34 patients but exceeded 1000 U/l in 12 of the 14 with a distinct P3 isoenzyme. Thus on the basis of a distinct P3 isoenzyme of amylase and an increased pancreatic lipase activity evidence of pancreatitis was found in 34% of patients in this series.

Puzzling persistent hyperamylasemia, probably neither pancreatic nor pathologic

Increased serum amylase levels most commonly signify pancreatic disease. One hundred seventeen consecutive patients were studied because their serum amylase levels were abnormally high for periods ranging from 3 to 48 weeks. In each case, extensive clinical and radiologic evaluation had failed to reveal a reason for the abnormality. The amylase isoenzymes of their sera were separated by polyacrylamide gel electrophoresis, and the fractions were measured by a saccharogenic assay. The findings in the 117 patients showed that 79 percent had non-pancreatic causes for their hyperamylasemia. The biggest single group (64 percent) had a normal distribution of isoamylases, albeit at unusually high concentrations. This phenomenon, which has not been defined previously, is probably a variant of normal in which the homeostatic balance between production and metabolism is set at a high level. Macroamylasemia accounted for 6 percent of the cases and salivary hyperamylasemia for only 9 percent. Three patients had the characteristic isoamylase pattern ("old amylase") associated with pancreatic pseudocysts. Isoamylase fractionation is a cheap, efficient, and effective means of ruling out a pancreatic cause for hyperamylasemia. It is probable that in the majority of cases of persistent hyperamylasemia without obvious clinical cause there will be no disease at all.

Hyperamylasemia and S-type isozyme dominance in liver cirrhosis

To investigate the mechanisms of serum amylase abnormalities in liver disease, we determined serum amylase levels, S-type isozyme proportion, clinical symptoms, and laboratory data in 38 cases of histologically confirmed liver cirrhosis and 19 controls. Of the 12 patients who were hyperamylasemic (12/38, 32%), 5 showed S-type isozyme dominance (5/12, 42%), whereas in the 26 normoamylasemic cirrhosis patients, only 5 were S-type isozyme dominant (5/26, 19%). Isozyme percentages were significantly higher (P less than 0.01) in the dominant-S-type cases than in the controls, and S-type dominance was found more frequently in the hyperamylasemic than in the normoamylasemic cirrhosis cases. Only ascites and esophageal varices were observed more frequently as clinical symptoms in the dominant-S-type cases. Our results suggest that amylase is not produced in the human liver, but that the decreased clearance rate of amylase, especially the S-type isozyme, may be a cause of hyperamylasemia and S-type isozyme dominance in cirrhosis.

Timing of surgical drainage for pancreatic pseudocyst. Clinical and chemical criteria

Traditional concepts of managing pancreatic pseudocysts have changed with the advent of computerized tomography (CT) and ultrasound scanning, but new misconceptions related to spontaneous resolution have replaced some old ones. This report shows a difference in natural history and treatment requirements when pseudocysts are associated with acute versus chronic pancreatitis. There were 42 consecutive patients with pseudocysts treated over 5 years. Thirty-one were known alcoholics, two had gallstone pancreatitis, and nine had idiopathic pancreatitis. An attack of acute pancreatitis was identifiable within 2 months preceding in 22 patients, but there were only chronic symptoms in 20. Spontaneous resolution of the pseudocyst occurred in three patients (7%), all of whom had recent acute idiopathic pancreatitis, normal serum amylase levels, and pancreatograms showing normal pancreatic ducts freely communicating with the pseudocyst. Factors associated with failure to resolve included known chronic pancreatitis, pancreatic duct changes of chronic pancreatitis, persistence greater than 6 weeks, and thick walls (when seen) on scan. Nearly all (18/19) patients with known chronic pancreatitis had successful internal drainage of the pseudocysts immediately upon admission, whereas 6/20 patients with antecedent acute pancreatitis were found to require external drainage at the time surgery was eventually elected. Isoamylase analysis, performed on serum from 19 patients by means of polyacrylamide gel electrophoresis, detected the abnormal pancreatic isoamylase pattern described as "old amylase" in 15. When old amylase was present in the serum, internal drainage was always possible (14/14). In four of five patients whose serum contained no detectable old amylase, internal drainage was not possible regardless of the length of prior observation. There were four nonfatal complications arising from an acute pseudocyst during the wait for maturity. It is concluded that prolonged waiting is expensive and unnecessary for pseudocysts in chronic pancreatitis when there has been no recent acute attack. However, pseudocysts developing after identifiable acute pancreatitis should be observed in the safety of a hospital for up to 6 weeks to allow for either spontaneous resolution or maturation of the cyst wall. The appearance of old amylase in the serum suggests that the pseudocyst wall has achieved sufficient maturity to allow safe internal anastomosis.

Serum amylase isoenzyme alterations in acute abdominal conditions

To determine the accuracy of the serum amylase in identifying a pancreatic source, amylase isoenzymes were determined prospectively in 65 patients initially evaluated with a complaint of abdominal pain and associated hyperamylasemia. Isoenzyme patterns were demonstrated by an electrophoretic technique, and the results were correlated with clinical diagnoses. Patients were divided into two diagnostic groups. Group I consisted of 42 patients with clinical findings suggesting pancreatitis. P-type isoenzymes were normal or elevated in 31 of these patients (74%), and s-type isoenzymes were normal or elevated in 11 (26%). Group 2 consisted of 23 patients with abdominal pain attributed to causes other than pancreatitis. Four patients (17%) had elevation of p-type isoenzymes, and 19 patients (83%) had predominantly s-type patterns. We conclude that amylase isoenzymes cannot determine unequivocally the cause of hyperamylasemia, but they can enhance the diagnostic specificity of the serum amylase. Elevated serum amylase with a predominant p-type pattern suggests pancreatic disease; elevation of s-type isoenzymes suggests but is not conclusive for, diagnoses other than pancreatitis. Hyperamylasemia with a normal isoenzyme pattern occurred in a few patients in both groups, and it was nondiagnostic.

Acute pancreatitis after cardiopulmonary bypass

We have described a spectrum of pancreatic surgery after cardiopulmonary bypass. At one end is a subclinical lesion which was manifested only by elevations in serum isoamylase levels (27 percent of patients) and increased ribonuclease levels (13 percent of patients) in asymptomatic patients followed after cardiac surgery. At the other end is a severe and often lethal necrotizing pancreatitis. Acute necrotizing pancreatitis was found at autopsy in 25 percent of 138 patients who died after cardiac surgery, and it correlated strongly with low output, acute tubular necrosis, and infarction of the liver, spleen, or bowel. It was the principal cause of death in 4 percent of these patients. In addition, 24 percent of 38 nonsurgical patients who died from cardiac failure and hypoperfusion had acute pancreatitis at autopsy, whereas acute pancreatitis was not observed in 55 nonsurgical patients who died without a significant period of low output. Acute pancreatitis was recognized postoperatively in 12 patients (0.2 percent). Three had mild pancreatitis, and all responded well to conservative therapy. In nine patients, fulminant necrotizing pancreatitis developed. Their courses were characterized by significant early postoperative hemodynamic compromise, abdominal distention, ileus, fever, and episodes of late vascular instability associated with hypocalcemia. The diagnosis of pancreatitis was usually missed because of the absence of pain, tenderness and hyperamylasemia. The diagnosis was confirmed at laparotomy in eight patients and at autopsy in one. The only two survivors among the nine with severe cases had aggressive mobilization, debridement, and wide drainage of the necrotic pancreas. We suggest that a mild subclinical injury to the pancreas may occur as a consequence of cardiopulmonary bypass and may progress to severe ischemic necrosis if hypoperfusion follows in the postoperative period, the presentation of necrotizing pancreatitis may be atypical in the cardiac surgical patient and should be considered if nonspecific abdominal symptoms are present, and aggressive debridement and drainage may be the optimal treatment for aggressive forms of this disease.

Biochemistry of human alpha amylase isoenzymes

The purpose of this article is to review recent literature on the isoenzymes of alpha amylase. Although some studies are cited from the literature of fields other than clinical biochemistry, the aim is to bring together findings that may be of interest to clinical laboratory physicians and scientists. It is hoped that this will be useful in suggesting further studies of amylase. To this end, the review is more selective than exhaustive. The review will discuss the history and chemistry alpha amylases, the measurement of amylase and amylase isoenzymes, posttranslational modifications of human amylases, and the genetics of human pancreatic and salivary amylases. Finally, we will discuss other tissue sources of amylase with emphasis on "genital" amylases and their relationship to the amylase found in serous ovarian tumors.

Identification of amylase isoenzymes in intestinal contents

Samples of intestinal contents were obtained from 16 patients: 5 from the midjejunum, 10 from the distal ileum, and 1 from the cecum. The presence of pancreatic and nonpancreatic isoamylases in these fluids was evaluated by an inhibitor assay (Pharmacia Corporation) and by polyacrylamide gel electrophoresis. In every sample the inhibitor assay detected the presence of pancreatic-type isoamylase but not salivary-type isoamylase. Electrophoresis confirmed that salivary-type isoamylase was totally absent. Therefore, in intestinal disorders which disrupt the intestinal mucosal barrier (such as ischemia, perforation, ulceration, or obstruction), the amylase which escapes from the intestinal lumen and is reabsorbed into the circulation is likely to consist entirely of pancreatic-type isoamylases. In these circumstances, measurement of serum amylase isoenzymes will not distinguish acute pancreatitis from an acute intraabdominal catastrophe requiring surgery.

Development of experimental cancer in the head of the pancreas by surgical induction of tissue injury

The majority of carcinomas of the pancreas in humans are of ductal origin and are located in the head of the gland. These clinical characteristics however, are not affected in traditional animal models of the disease. Partial pancreatic duct obstruction with ductal epithelial hyperplasia was produced in the Syrian golden hamster by wrapping the head of the pancreas with cellophane tape. Wrapped and unwrapped animals were then exposed to an exogenous carcinogen (N-nitrosobis[2-oxopropyl]amine). Assay of serum ribonuclease activity was used as a marker of disease. Invasive lesions developed in both groups of animals. Fifty percent of the tumors in the Group II (cellophane wrap and N-nitrosobis [2-oxopropyl] amine) hamsters were located in the head of the gland and were of ductal origin. All tumors in animals receiving N-nitrosobis [2-oxopropyl]amine alone (Group I) occurred peripherally and were derived from ductular or acinar tissue. Elevation of serum ribonuclease activity was noted early in the course of carcinogenesis, thereafter returning to normal, which may explain the clinical controversy regarding this marker. This new model should enhance our knowledge of the interrelationships between etiologic factors, precursor lesions, and pancreatic cancer.

Serum and urinary amylase isoenzymes in carcinoma of the prostate

Serum and urinary amylase isoenzyme activities were evaluated in 70 patients with carcinoma of the prostate. The results were compared with amylase isoenzyme activities fo 20 healthy man and 30 patients with benign prostatic hypertrophy. Increased serum S-type amylase activity was found in 13 patients (18%) with carcinoma of the prostate, whereas no changes of this isoenzyme was found in benign prostatic hypertrophy. No significant changes of serum P-type amylase activities were observed in our patients.

Clinical significance of elevated serum and urine amylase levels in patients with appendicitis

During the 45 month period beginning January 1977, 251 patients with a pathologically confirmed diagnosis of acute appendicitis underwent celiotomy at the Medical College of Virginia Hospital. A preoperative serum or urine amylase determination was recorded in 155 of the patients (62 percent). Of this group, 15 patients (10 percent) had elevation of serum amylase or 2 hour urine amylase. Hyperamylasemia or hyperamylasuria directly led to misdiagnosis or treatment delay in 5 of the 15 patients. Appendiceal rupture occurred in three patients, two of whom had prolonged (greater than 1 month) hospitalizations directly attributable to the misdiagnosis. As a result of this study, we conclude that (1) acute appendicitis and elevated amylase levels may occur concurrently, (2) hyperamylasemia or hyperamylasuria should not dissuade the surgeon from early operation if other clinical features suggest appendicitis, and (3) abdominal pain and elevation of amylase level define significant intraabdominal disease, not specifically pancreatic disease.

Serum amylase and its isoenzymes in cases of viral hepatitis

Serum amylase (SA) and its isoenzymes were studied in 9 control cases and 26 cases of Viral Hepatitis (VH). A significant rise in SA level was found in VH cases (Mean value--287.15 + 100.64) as compared to control cases (Mean value--155.56 + 28.57). The value was markedly increased in 8 cases with hepatic encephalopathy (Mean value--388 + 57.21). Isoenzymes of SA were estimated in all the cases by means of polyacrylamide gel electrophoresis and a direct saccharogenic assay of amylase activity. Besides two regular peaks (Pancreatic and Salivary fractions) a third peak (Slowest of all) was noticed in 4 out of 9 control cases (44.5%) and 19 out of 26 cases of VH (73.1%). Out of 8 cases who developed hepatic encephalopathy during the course, 7 had this peak (87.5%). SA levels and its isoenzymes level correlated well with the extent of hepatic damage (SGPT and Serum bilirubin levels). The possibility of hepatic origin of the third peak has been discussed.

Serous ovarian neoplastic amylase (SONA): a potentially useful marker for serous ovarian tumors

A series of cystic ovarian tumors was studied with regard to amylase activity in the cyst fluid. Large amounts of amylase activity were present only in those patients with endosalpingeal-type lining epithelium (serous ovarian neoplasms). The amylase activity from two such patients was further characterized using G75 Sephadex chromatography, DEAE Sephadex chromatography, agarose gel chromatography, isoelectric focusing, and heat inactivation studies. Serous ovarian neoplastic amylase (SONA) exhibited properties different from amylases of pancreatic and salivary gland origin. Serous ovarian neoplastic amylase (SONA) may be a pancreatic and salivary gland origin. Serous ovarian neoplastic amylase (SONA) may be a useful biochemical marker in diagnosing and managing patients with serous ovarian neoplasms.

Prevalence and nature of hyperamylasemia in acute alcoholism

Determination of serum amylase activity in 100 consecutive patients admitted to an alcohol detoxification unit revealed hyperamylasemia in 39 cases. Further clinical evaluation of 15 of the 39 alcoholic patients with hyperamylasemia was unremarkable except for bilateral enlargement of the parotid glands in two cases. Nine of the 15 patients demonstrated markedly low amylase to creatinine clearance ratio; however, macroamylase complexes were not detected in the sera of any patients. Serum isoamylase separation revealed that the mean salivary isoamylase for the 15 alcoholic patients was significantly (P less than 0.05) elevated as compared to the control values. Individually, the salivary-type isoamylase was clearly elevated in ten patients while pancreatic type isoamylase was elevated in four. These data indicate that elevated serum amylase activity occurs frequently in alcoholic patients. Hyperamylasemia in a large number of alcoholic patients is nonpancreatic in origin and may be related to the injurious effect of ethanol on salivary glands and other tissues.

The diagnosis of exocrine pancreatic disease: the present position reviewed

In this paper, recent advances in the diagnosis of pancreatic disease are reviewed, together with older methods currently in use. The clinical role of these techniques in the diagnosis of pancreatic disease is discussed with particular reference to symptomatology and prognosis of the various pancreatic disorders. Likely future developments in this field are considered.

Sensitivity and specificity of serum ribonuclease in the diagnosis of pancreatic cancer

The serum levels of a poly-[C]-specific acid ribonuclease (RNase) found in the pancreas was measured in 40 normal persons and 137 patients with pancreatic cancer, other cancers, obstructive jaundice, acute pancreatitis or chronic pancreatitis. Serum RNase increased by as much as 800 percent above normal in 69 percent of patients with pancreatic cancer. Analysis of the serum isoenzymes of RNase by isoelectric focusing did not reveal any unique RNases produced by the tumours. In contrast, serum RNase rose in only 8 percent of patients with other cancers, 11 percent of other patients with obstructive jaundice and in no patients with chronic pancreatitis. These data suggest that the finding of increased serum RNase is of adjunctive value inthe diagnosis of pancreatic carcinoma and may be particularly helpful in distinguishing it from other causes of biliary obstruction and from chronic pancreatitis.

Pancreatic enzyme levels in bile of patients with extrahepatic biliary tract disease

A total of ninety three patients with biliary tract disease were studied to determine the concentration of the pancreatic enzymes, amylase and lipase, in bile obtained from the gallbladder and/or common bile duct. Of seventy gallbladder bile samples, amylase levels were higher than actual or predicted serum levels in 87 per cent, while bile lipase were higher than serum lipase values in 66 per cent. Bile obtained from the common bile duct had enzyme concentrations which fluctuated from values similar to those in serum to remarkably high levels. This suggests that pancreatic enzymes enter the biliary system through a common terminal ampulla which is known to exist in 60 to 90 per cent of human subjects. The premise is advanced that pancreatic enzymes may initiate inflammatory changes in the gallbladder and could play a role in gallstone formation by altering the constituents which maintain cholesterol in a soluble state. Biliary reflux of pancreatic enzymes could play a role in the pathogenesis of some cases of cholecystitis can cholelithiasis.

Pancreatitis-like isoamylase pattern in normal persons

On the assumption that a rise in the pancreatic type isoamylases may not necessarily indicate underlying pancreatitis, genetic studies of human serum and urinary amylase isoenzymes have been performed with the use of electrophoresis. Although the preponderant increase in the two principal pancreatic isoamylases Amylase-1 and 2 has been accepted to be a specific index of pancreatic involvement, 1.68% of normal persons had Amylase-2 with an elevated amylase activity (named "Dominant Amylase-2") up to the same levels as the major isoenzymes. Results of pancreozymin-secretin test and other laboratory findings of these persons with Dominant Amylase-2 were all within normal ranges. Pedigree studies confirmed an autosomal dominant mode of inheritance for this variant. The important of serial determination and pedigree investigations has been shown to distinguish normal persons having Dominant Amylase-2 from patients with pancreatitis without elevated amylase activity. The existence of an inherited trait of pancreatitis-like isoamylase pattern in healthy individuals must be born in mind before coming to a conclusion when amylase isoenzymes are used for clinical medicine, though preponderance of the pancreatic type isoenzymes in serum and urine has been revealed to be a characteristic finding in pancreatitis. Knowledge of amylase genetic polymorphism provides a scientific basis for amylase isoenzyme interpretation.

Susceptibility of the pancreas to ischemic injury in shock

The pancreas, like the kidney, is highly vulnerable to ischemic necrosis. This form of pancreatic injury may express itself as prolonged hyperamylasemia with only minimal signs or symptoms of inflammation, or may produce severe pancreatitis followed by abscesses and death. Autopsy examination of patients dying after oligemic shock showed a 9% incidence of major pancreatic injury if there was not concomitant acute renal tubular necrosis (ATN), but a 50% incidence in those with ATN. Similarly, among patients dying after non-oligemic shock, 12% of those without ATN had major pancreatic injury but 35% with ATN also had pancreatic ischemic injury. Among 13 selected patients examined prospectively after being in shock, pancreatic injury was indicated by hyperamylasemia, hyperlipasemia, elevated amylase/creatinine clearance ratio, and elevated circulating isoamylases specifically of pancreatic origin. Four of the 13 had clinical manifestations of pancreatitis. Not only must shock be added to this list of causes of pancreatitis, but pancreatic ischemia due to hypoperfusion may also be the critical factor which causes the progression from edema to necrosis in other forms of pancreatitis, including those associated with alcohol and biliary disease.

Clinical evaluation of the pancreatitis-like isoamylase pattern in normal persons

Amylase isoenzyme analysis of serum and urine has been performed in 4001 normal persons and 500 patients with various disease using electrophoresis on thin layer polyacrylamide gel. Although elevation of amylase activity in amylase-1 and 2 has been reported to be the specific findings in patients with pancreatitis, 1.69% of normal persons had an elevated Amylase-2(named "Dominant Amylase-2") up to the same levels as major isoenzymes (Amylase-1 and 3), along with Amylase-1. Pedigree study confirmed an autosomal dominant mode of inheritance for Dominant Amylase-2. Knowledge of the genetic polymorphism is of importance in clinical assessment of amylase isoenzymes in patients having an elevated Amylase-2 suggestive of pancreatitis. Predominance of the pancreatic components in serum and urine has been revealed to be a specific index of pancreatic involvement. However, the existecne of an inherited trait of pancreatitis-like isoamylase pattern in healthy individuals must be borne in mind. On the basis of the present study, it may be concluded that a rise in the pancreatic type isoenzymes may not necessarily indicate underlying pancreatitis, especially in the absence of elevated amylase and lipase levels.

Macroamylasemia and other chronic nonspecific hyperamylasemias: chemical oddities or clinical entities?

Seventeen patients with chronic hyperamylasemia were studied using standard clinical and laboratory parameters, amylase/creatinine clearance ratios, and polyacrylamide gel electrophoresis of serum amylases. These patients, none of whom had evidence of pancreatic disease or other specific source for the elevated serum amylase, fell into three groups: (1) Normal serum isoamylase profile and normal amylase clearance (6 patients). We postulate that the generalized hyperamylasemia may be due to reduced extrarenal catabolism of amylase, a previously undescribed phenomenon. (2) Macroamylasemia and very low amylase clearance (9 patients). Seven of the nine patients had recurrent epigastric pain. Evidence for an autoimmune basis is discussed. (3) Salivary-type hyperamylasemia and low amylase clearance (2 patients). This entity may really be macroamylasemia in which the macroamylase complex dissociated during analysis. Chronic hyperamylasemia is often not of pancreatic origin. The assumption that the pancreas is at fault, especially if there is abdominal pain, may cause morbidity due to gross overtreatment.