Circulating concentrations of trypsin-like immunoreactivity and activities of lipase and amylase after pancreatic duct ligation in dogs

The possibility that assay of circulating trypsin-like immunoreactivity (TLI) could assist in the diagnosis of acute pancreatitis in dogs has been examined by assaying plasma TLI concentrations after pancreatic duct ligation and comparing the results with plasma activities of lipase and amylase. Venous blood samples were obtained from 8 dogs before surgery, then daily for 5 days and at 14 days after ligation of pancreatic ducts. Plasma concentrations of TLI increased within 24 hours and tended to peak before and to decrease more rapidly than activities of lipase and amylase, remaining greater than the control range for 5 days in all but 2 dogs. Plasma lipase and amylase activities increased together and remained greater than the control range in all dogs for 5 days after surgery. Regression analysis of all postoperative data indicated significant correlations between concentration of TLI and lipase activity (r = 0.67, P less than 0.001), concentration of TLI and amylase activity (r = 0.53, P less than 0.001), and between lipase and amylase activities (r = 0.74, P less than 0.001). These findings suggested that assay of TLI may provide an early indication of acute pancreatitis in dogs. Because TLI is specifically pancreatic in origin, high plasma TLI concentration may prove a more reliable indicator of clinical pancreatitis than high activities of amylase or lipase, which may be derived from extrapancreatic tissues.     

Comparison of amylase and lipase activities in serum and plasma of dogs

BACKGROUND: Amylase and lipase activities are most often determined in serum, although heparinized plasma is more convenient to obtain and is used for many routine biochemical analyses. OBJECTIVE: The purpose of this study was to compare amylase and lipase activities in serum and plasma of dogs and to determine whether either specimen type is acceptable for analysis. METHODS: Serum and heparinized plasma were obtained from 101 randomly selected dogs and analyzed in parallel for alpha-amylase and lipase. Results were compared using Passing-Bablock regression, Bland-Altman difference plots, and correlation analysis. RESULTS: There was a high correlation between the results obtained from serum and those from plasma. Regressions (with 95% confidence intervals in parentheses) were as follows: lipase(plasma) = 0.984 (0.976/0.995) Chi lipase(serum) - 0.9 (2.9/0.7) (r =.999); a-amylase(plasma) = 1.003 (0.977/1.032) Chi alpha-amylase(serum) - 1.9 ( 20.7/23.3) (r =.991). Mean differences (serum - plasma) were 8 U/L and 4 U/L for lipase and alpha-amylase, respectively. Classification of results as normal or abnormal did not differ according to specimen type. CONCLUSION: In dogs, lipase and alpha-amylase activities can be determined with the same level of accuracy in serum and in heparinized plasma.     

Serum amylase and lipase activities after exploratory laparotomy in dogs

Serum amylase and lipase activities and creatinine concentration were determined before surgery, and at 1 and 2 days after exploratory laparotomy in 24 dogs. Examination of all viscera was done during each laparotomy, but a surgical procedure was not performed. The mean serum activities for lipase were: before surgery, 0.71 (0.0 to 2.0) Cherry Crandall units (CCU)/L; 1 day after surgery, 2.1 (0.0 to 4.5) CCU/L; and 2 days after surgery, 1.19 (0.0 to 3.9) CCU/L. The mean serum activities for amylase were: before surgery, 1,958 (1,027 to 3,426) IU/L; 1 day after surgery, 1,538 (937 to 2,659) IU/L; and 2 days after surgery, 1,663 (1,066 to 2,274) IU/L. Serum creatinine concentrations before surgery, 1 day after surgery, and 2 days after surgery were 0.88 (0.2 to 1.7) mg/dl, 0.78 (0.4 to 1.3) mg/dl, and 0.78 (0.3 to 1.3) mg/dl, respectively. Mean preoperative, day-1, and day-2 serum amylase activities and serum creatinine concentrations did not differ significantly from each other. Mean preoperative and day-2 serum lipase activities did not differ significantly; however, mean serum lipase activity was significantly greater when day 1 activities were compared with preoperative activities (P = 0.0002). Post-mortem examinations revealed no gross or histologic evidence of pancreatitis in any dog. The results of this study show that a 3 or more fold increase in serum lipase activity may occur after routine exploratory laparotomy in dogs without clinical signs or gross evidence of pancreatitis. Histologic evidence of pancreatitis was not found in the right pancreatic lobes in any dog.     

Serum amylase and lipase activities in the diagnosis of pancreatitis in dogs

To determine the usefulness of information provided by measurement of serum amylase activity in the evaluation of dogs for pancreatitis, the relationship of amylase activity to lipase activity in 713 paired serum samples was investigated by statistical analysis. Little change in mean amylase concentration was found until lipase values exceeded 800 U/L. The ranges of amylase activity (mean +/- 2 SD) were essentially the same for dogs with no pancreatitis (0 to 100 U of lipase activity/L) as for dogs with a high probability for the disease (700 to 799 U of lipase activity/L), 0 to 4,029 U/L and 857 to 4,869 U/L, respectively. Pathologic findings from biopsy and necropsy reports from 92 dogs for which serum lipase determinations were done indicated that serum lipase increased not only with pancreatitis, but also with other medical problems, such as renal and hepatic disease. It was concluded that determination of serum amylase activity without knowledge of serum lipase activity was of little value to diagnose pancreatitis. High amylase activity was not specific for pancreatitis and low amylase activity could not rule out the disease. The results of this study also showed that low serum lipase values almost always eliminated the possibility of pancreatitis and that high values were often, but not always, diagnostic for pancreatitis.     

Serum lipase activities and pancreatic lipase immunoreactivity concentrations in dogs with exocrine pancreatic insufficiency

OBJECTIVE: To determine serum lipase activities and pancreatic lipase immunoreactivity (PLI) concentrations in dogs with exocrine pancreatic insufficiency (EPI). ANIMALS: 74 healthy dogs and 25 dogs with EPI. PROCEDURES: A diagnosis of EPI was made on the basis of clinical signs, low serum trypsin like immunoreactivity (TLI) concentration, and response to treatment with enzyme replacement. Median values for fasting serum lipase activity and serum PLI concentrations were compared between the 2 groups with a Mann-Whitney U test. RESULTS: Median fasting serum lipase activity was not significantly different between dogs with EPI (366.0 U/L) and healthy dogs (294.5 U/L), and only 1 dog with EPI had a serum lipase activity less than the lower limit of the reference range. Median serum PLI concentration was significantly lower in dogs with EPI (0.1 microg/L) than in healthy dogs (16.3 microg/L). All dogs with EPI had serum PLI concentrations less than the lower limit of the reference range. CONCLUSION AND CLINICAL RELEVANCE: Serum lipase activity is not limited to the exocrine pancreas in origin, whereas serum PLI is derived only from the exocrine pancreas. Unlike in serum TLI concentrations, there was a small degree of overlap in serum PLI concentrations between healthy dogs and dogs with EPI. Serum TLI concentration remains the test of choice for diagnosis of EPI.     

Serum amylase and isoamylase values in dogs with pancreatic disease

Serum amylase and isoamylase values were determined in three groups of dogs. The first group contained control dogs while the other groups contained dogs with confirmed exocrine pancreatic insufficiency and diabetes mellitus respectively. The trypsin-like immunoreactivity test was also carried out on sera from dogs with exocrine pancreatic disease (EPI). A significant difference was detected in the serum amylase values between the three groups which may be of limited diagnostic value. Dogs with EPI had values lower than normal while those with diabetes mellitus had values higher than control dogs. No evidence of exocrine pancreatic insufficiency was found in dogs with diabetes mellitus.     

Effects of dexamethasone on pancreatic tissue and on serum amylase and lipase activities in dogs

The effects of dexamethasone on the pancreas and on pancreatic amylase and lipase activities were determined in clinically normal dogs and in dogs with neurologic disease. Dexamethasone increased serum lipase activity without any histologic damage to the pancreas in either group of dogs. It decreased serum amylase activity in the normal dogs and had a variable effect in dogs with neurologic disease, with or without confirmed pancreatitis. It was suggested that high serum lipase activity in dexamethasone-treated dogs may not be attributable to pancreatitis and that the reasons are still unknown. It was concluded that high serum lipase activity is an unreliable basis for diagnosis of pancreatitis in dogs treated with dexamethasone. The data allowed no conclusion about an additive effect of dexamethasone and neurologic disease causing pancreatitis.     

Effects of xylazine administration on serum amylase, pancreas-specific isoamylase and pancreatic polypeptide in normal dogs.

Changes in serum total amylase, pancreas-specific isoamylase and pancreatic polypeptide activities were measured in six dogs following multiple intramuscular injections of xylazine at 0.5 mg/kg of body weight. The activities of those analytes did not change over 24 hours of study.     

Prednisone treatment alters the serum amylase and lipase activities in normal dogs without causing pancreatitis.

In order to test the hypothesis that treatment with glucocorticoids causes pancreatitis in dogs, 18 mongrel dogs were divided into three groups of six individuals, each group receiving prednisone at different doses orally or intramuscularly for two weeks. Two groups consisting of six dogs each served as controls. Treatment for two weeks with oral prednisone at 1.2 mg/kg body weight or at 4 mg/kg body weight daily decreased the serum amylase activities, but increased the serum lipase activities. Postmortem examinations revealed microscopic evidence of mild pancreatitis in only one dog given prednisone, that clinically appeared normal. It was concluded that daily doses of 4 mg prednisone/kg body weight or less given orally or intramuscularly for two weeks do not cause pancreatitis in dogs.     

Effects of dexamethasone administration on serum trypsin-like immunoreactivity in healthy dogs

OBJECTIVE: To determine whether administration of dexamethasone altered serum trypsin-like immunoreactivity (TLI) in healthy dogs. ANIMALS: 12 healthy dogs. PROCEDURE: Dexamethasone (0.25 mg/kg, p.o., q 24 h) was administered for 7 days. Serum TLI, alpha-amylase and alanine aminotransferase (ALT) activities, and urea and creatinine concentrations were determined on days 0, 7, 14, and 21 of the study. RESULTS: Serum TLI and ALT activities were significantly increased, and serum alpha-amylase activity was significantly decreased after administration of dexamethasone for 7 days. However, values obtained on days 14 and 21 were not significantly different from baseline values. Dexamethasone administration was not associated with any significant changes in serum creatinine or urea concentrations. Serum TLI and alpha-amylase activities were significantly correlated prior to dexamethasone administration. Dogs did not develop clinical signs of pancreatitis. CONCLUSIONS AND CLINICAL RELEVANCE: Dexamethasone administration was associated with an increase in serum TLI. However, values returned to baseline 7 days after dexamethasone administration was discontinued. Serum TLI may be falsely high in dogs that have been treated with dexamethasone in the week preceding analysis.     

Relationship between dietary protein concentration and serum trypsin-like immunoreactivity in dogs

Serum trypsinogen concentration was studied in 6 adult mixed-breed dogs randomly fed diets containing 6.8, 31.4, or 39.7% protein (dry weight) for 3 weeks each. Blood was collected on days 20, 21, and 22 of each feeding period, and serum trypsinogen concentrations were determined by radioimmunoassay of trypsin-like immunoreactivity (TLI). Mean serum TLI concentrations for each dog fed each diet were compared. A significant (P less than 0.05) positive linear relationship (P less than 0.02) was determined between serum TLI concentrations and the percentage of dietary protein. Mean serum TLI concentrations for each dog fed all diets ranged from 5.7 to 20.2 micrograms/L.     

Proteinase, lipase and amylase activities in the small intestine of pigs suffering from colienterotoxaemia.

The activities of proteinases, lipases, amylases and the activities of proteinase inhibitors, as well as the numbers of Escherichia coli in the contents from the small intestine were examined for pigs suffering from colienterotoxaemia and for healthy pigs. Enzyme activities were determined using an agar diffusion test.Compared with healthy animals the activities of proteinases and amylases in diseased animals were reduced while lipases showed increased activity. In pathologically changed contents showing large numbers of E. coli, proteinases could not be demonstrated; however, proteinase inhibitors were found in these contents. In healthy animals, proteinase inhibitors were not demonstrated in ingesta-con-taining contents.In diseased animals, E. coli were found in large numbers in all parts of the small intestine. In healthy animals, E. coli was demonstrated especially in the posterior part of the small intestine and regularly in small numbers.The possible influence of digestive enzymes, especially proteinases and their inhibitors, on enterotoxins from E. coli is discussed.     

Influence of feeding on serum feline trypsin-like immunoreactivity.

OBJECTIVE: To determine whether feeding causes a change in feline trypsin-like immunoreactivity (fTLI) in serum from healthy cats. ANIMALS: 6 healthy domestic shorthair cats. PROCEDURES: For the first 12 days of the study, 3 cats were fed a high-protein, high-fat (diet 1), and the other 3 were fed a maintenance (diet 2). On day 12, diets were switched, and cats were fed the other diet for the remaining 12 days of the study. On days 11 and 23, food was withheld for 24 hours, and baseline serum fTLI was measured. Cats were offered food equivalent to half their daily caloric maintenance requirements, and serum fTLI was measured 1, 2, 4, 6, 12, and 24 hours later. Uneaten food was removed after 1 hour. RESULTS: Overall mean +/- SD serum fTLI was 22.7 +/- 5.8 micrograms/L when cats were fed diet 1 and 21.1 +/- 5.0 micrograms/L when cats were fed diet 2. There was no significant difference in serum fTLI over time or between diets. However, there was a statistically significant, but clinically unimportant (mean increase, 1.7 micrograms/L), increase in serum fTLI, compared with baseline values, 1 hour after cats were fed diet 2 but not when cats were fed diet 1. CONCLUSIONS AND CLINICAL RELEVANCE: A maintenance diet may cause a clinically unimportant increase in serum fTLI 1 hour after feeding in healthy cats. Results suggest that for healthy cats, it is not necessary to withhold food before collecting samples for determination of fTLI in serum. Whether feeding changes fTLI in serum from cats with disorders of the exocrine portion of the pancreas remains to be determined.     

Serum values of amylase and pancreatic lipase in healthy mature dogs and dogs with experimental pancreatitis

Serum values of amylase and pancreatic lipase were determined by the iodometric and the turbidimetric methods, respectively, in 44 mature healthy dogs and in 8 dogs with experimentally induced pancreatitis (plus 1 sham-operated control). Serum value of amylase in mature healthy dogs varied from 250 to 1,500 Caraway units/dl and that of pancreatic lipase varied from 0 to 50 IU/L. Maximal serum values of amylase and pancreatic lipase in the dogs with experimentally induced pancreatitis varied from 4,540 to 14,000 Caraway units/dl and 325 to 810 IU/L, respectively. Following pancreatic damage, serum values of amylase and pancreatic lipase increased rapidly in the 8 dogs and ran parallel to each other in 6 of the 8 dogs studied. However, the serum value of amylase returned to within normal range earlier than the serum value of pancreatic lipase in 2 dogs; the reverse was true in 2 other dogs.     

Sensitivity and specificity of canine serum total amylase and isoamylase activity determinations.

Serum isoamylases were determined prospectively in dogs with pancreatic and extrapancreatic diseases. Mean serum isoamylase determinations were significantly different (p less than 0.05) between normal dogs and dogs with pancreatitis and exocrine pancreatic insufficiency. The sensitivity of serum isoamylase determination exceeded that of total amylase activity for the diagnosis of pancreatitis. Serum isoamylase determinations were less influenced by extrapancreatic diseases compared to total amylase activity when used in the diagnosis of pancreatic disease. Neither serum isoamylase determination nor total amylase activity had adequate sensitivity to support their use in the diagnosis of exocrine pancreatic insufficiency. There were significant (p less than 0.05) linear correlations between isoamylase determinations, total amylase activity, and trypsin-like immunoreactivity concentration.     

Biological variability of C-reactive protein and specific canine pancreatic lipase immunoreactivity in apparently healthy dogs

Background: C‐reactive protein (CRP) and specific canine pancreatic lipase immunoreactivity (Spec cPL) are biomarkers of generalized or nonspecific inflammation and pancreatic inflammation in dogs, respectively. The extent of inter‐ and intraindividual variation over time of these analytes is not well defined in dogs. The minimal critical difference for sequential determinations of these markers (ie, the smallest change necessary to represent physiological change rather than biological variation), has not been defined. Objectives: To determine the inter‐ and intraindividual variability (CV_G and CV_I) and minimal critical difference for sequential determinations of serum CRP and Spec cPL concentrations in apparently healthy dogs. Animals: Eleven apparently healthy dogs owned by staff or students at a veterinary teaching hospital. Methods: Blood was collected repeatedly at varying intervals over 12 weeks. CRP and Spec cPL concentrations were determined with commercially available assays. Indices of inter‐, intraindividual, and assay variability and 1‐sided minimal critical differences for sequential concentrations were calculated. Results: For CRP, CV_G was 90.8%, CV_I was 115.5%, and the analytical variability (CV_A) was 6.3%; the index of individuality was 0.74, and 1‐sided critical difference was 269.9%. For Spec cPL, CV_G= 49.48%, CV_I= 193.8%, CV_A= 8.4%, index of individuality = 0.24, and 1‐sided critical difference was 452.6%. Conclusions and Clinical Importance: A population‐based reference range is appropriate for Spec cPL, but questionable for CRP in dogs. Large changes in serial measurements of Spec cPL are necessary to infer clinical importance, more modest changes in CRP are likely to be meaningful.