Serum immunoreactive trypsin concentration after a Lundh meal. Its value in the diagnosis of pancreatic disease.

The changes in serum trypsin concentration have been measured in 47 subjects for up to 2 hours after a Lundh meal. In 18 healthy controls, mean fasting trypsin concentration was 285 +/- 125 ng/ml (mean +/- 2 SD). The maximum increase after the Lundh meal (the trypsin response ratio) was 6.7 +/- 7.5%. Six patients with chronic renal failure had elevated fasting serum trypsin concentrations (range 460-1100 ng/ml) but trypsin response ratios fell within the control range. Of five patients with relapsing pancreatitis, two had raised and three normal or low fasting trypsins. After stimulation two had elevated trypsin response ratios; one of the two had evidence of main duct obstruction. Eleven out of 12 patients with chronic pancreatitis (with or without insufficiency) had low fasting trypsin concentrations (range 0-120 ng/ml) Seven of the 12 also had raised trypsin response ratios. In six patients with cancer of the pancreas, fasting trypsin was low in three, normal in two, and raised in one. Both patients with a normal fasting level had a raised trypsin response ratio. The combination of a single estimation of fasting serum trypsin concentration followed by serial measurements after a Lundh meal provides a useful screening test for chronic pancreatic disease.

The decay of endogenously labelled 75Se-selenomethionine labelled proteins in duodenal juice: evidence for recirculation in man.

The decay of the specific radioactivity of duodenal juice proteins, endogenously labelled with 75Se-selenomethionine has been studied in man. Duodenal juice was collected against a background infusion of cholecystokinin-pancreozymin (1 unit/kg/hr) and secretin (1 unit/Kg/hr). In 4 subjects, duodenal juice was aspirated continuously and pooled in 30 min. aliquots. In 3 other subjects approximately 5-10 ml of juice was removed at 15 min, intervals. The rate of decay of protein specific radioactivity was significantly more rapid in the drainage group (p less than 0.01). A similar trend was also observed for trypsin. The data suggests that endogenous duodenal juice proteins might be recirculated as intact proteins in man.

The use of Bond-Elut for the estimation of serum bile pigments bonded covalently to albumin.

A simple and precise method has been devised for the quantitation of biliprotein (delta-bilirubin or albumin bound bilirubin) in serum. In the presence of caffeine/benzoate, Bond-Elut (C8, 200 mg) extracts unconjugated and conjugated bilirubin but not pigments that are covalently bonded to albumin which pass through the column and can be quantitated by a standard diazo method. Following elution from the Bond-Elut column with methanol-acetonitrile (50:50, v/v) unconjugated and conjugated bilirubin can be quantitated either as total pigments or individually by HPLC.

The effect of secretin on bile flow and bile acid and bilirubin excretion following relief of prolonged bile duct obstruction in the rat.

Bile flow was re-established in rats whose bile ducts had been obstructed for 5, 10, 15 and 28 days (Groups I, II, III and IV, n = 5). The effect of i.v. secretin on bile flow in control rats, whose bile ducts had been cannulated, was minimal, but in cholestatic rats there was an immediate response which was related to the duration of the obstruction and the degree of bile duct proliferation. In 40 min the mean excess bile flow production amounted to 76, 258, 320 and 432 microliters/100 g body wt. in Groups I, II, III and IV, respectively. Choleresis was prolonged in the Group IV rats that had developed cirrhosis. Synthetic secretin had a minimal effect on bile acid and bilirubin excretion. It is postulated that the proliferating bile ductules are the site of secretin choleresis, although the possibility that reduced inactivation of the hormone plays a role cannot be excluded.

Urinary immunoreactive trypsin excretion: a non-invasive screening test for pancreatic cancer.

The ratio of renal clearance of immunoreactive trypsin relative to renal clearance of creatinine was measured in 71 subjects including 27 controls and patients with cancer of pancreas, chronic pancreatitis, and acute pancreatitis. The upper limit of the control range was 4.1 x 10(-5) (mean + 2SD). 6 of 9 patients (67%) with acute pancreatitis had raised values. All 18 patients with chronic pancreatitis had values within the control range. In contrast, all 17 patients with carcinoma of pancreas had raised clearance ratios. The test may therefore prove valuable in distinguishing between chronic pancreatitis and cancer of pancreas.

The relative values of serum immuno-reactive trypsin concentration and total amylase activity in the diagnosis of mumps, chronic renal failure, and pancreatic disease.

Fasting serum concentrations of trypsin and amylase activity have been compared in 107 subjects, including 18 controls and patients with mumps, acute pancreatitis, chronic pancreatitis, cancer of the pancreas, and chronic renal failure. There was no significant correlation between amylase activity and trypsin concentrations in any of these groups. In all 12 patients with acute pancreatitis and all 16 with chronic renal failure the serum immuno-reactive trypsin concentrations were elevated. Amylase activity was increased in 87% (20 out of 23) of patients with mumps, but only 13% (3 out of 23) had hypertrypsinaemia suggesting subclinical pancreatitis. In 18 patients with chronic pancreatitis low levels of serum trypsin were measured in 11 (61%), reflecting a decrease in pancreatic acinar mass. In contrast, serum amylase was normal or raised in all 18. Subnormal values of the trypsin to amylase ratio was obtained in 15 (83%). Trypsin levels in 20 patients with carcinoma of the pancreas were abnormal in 11 (55%). Six (30%) had abnormal amylase levels. It is concluded that it is more useful to measure the serum trypsin concentration than the amylase activity in the diagnosis of both mumps-pancreatitis and chronic pancreatic disease and that the trypsin to amylase ratio is more sensitive than either enzyme alone in the diagnosis of chronic pancreatitis.

Pancreatic hypofunction in extrahepatic portal venous obstruction.

Pancreatic function was studied in 29 patients with extrahepatic portal venous obstruction, and 30 age-matched controls. The aetiology of the portal venous obstruction was known in 20 out of 29 patients. No patient had a history of pancreatitis. Serum trypsin, both fasting and for 120 minutes after a Lundh meal, was significantly lower in the patients than in controls (P less than 0.005). 5/28 (18%) patients had reduced fasting serum trypsin levels and in 5/14 trypsin was abnormal after a Lundh meal. Mean fasting serum glucose (3.8 +/- ).49 mmol/l was significantly higher than in control subjects (mean 3.4 +/- 0.42 mmol/l) (P less than 0.05). After 100 g glucose orally, mean serum glucose at 180 minutes (5.26 +/- 1.58 mmol/l) was higher than the control value (3.96 +/- 1.45 mmol/l) (P less than 0.05), and 30 and 60 minutes serum C-peptide values were significantly lower (P less than 0.005). Pancreatic hypofunction found in these patients probably results from an abnormal portal circulation in association with mild pancreatic damage secondary to chronic venous congestion.

Measurement of trypsin in duodenal juice by radioimmunoassay.

Trypsin in duodenal aspirate and pure pancreatic juice samples has been measured by both radioimmunoassay and enzymatic mathods. The radioimmunossay has been shown to be specific and to detect trypsin in the presence of aprotinin (Trasylol). In duodenal juice samples from control subjects and from patients with primary biliary cirrhosis a good correlation was obtained between both immunoreactive trypsin concentration and trypsin activity. The immunoreactive trypsinogen concentration in pure pancreatic juice also correlated well with activated trypsin activity. The mean immunoreactive trypsin concentration and the concentration of enzymatically inert immunoreactive trypsin in duodenal juice samples from patients with primary biliary cirrhosis were significantly lower than controls, suggesting pancreatic hyposecretion in this disease. After five duodenal juice samples had been stored for three months at -70 degrees C, immunoreactive trypsin concentration in samples stored without Trasylol were reduced by 12 . 0 +/- 4 . 2 (mean +/- SD) times the concentration of samples stored in Trasylol. Trypsin autodegradation continues even at -70 degrees C; Trasylol protects against this. Radioimmunoassay is a reliable method of trypsin estimation in duodenal juice and has advantages over conventional enzymatic analysis.

Metabolism of 125I-labelled trypsin in man: evidence of recirculation.

125I-labelled human trypsin metabolism has been investigated in man. Three subjects received 125I-trypsin and 131I-albumin intravenously. Against a background secretin infusion (1 U/kg/h), trypsin decayed biexponentially from the serum with half-lives of 17.5, 21, and 24 minutes for the rapid disappearance phase and 520, 540, and 560 minutes for the slow phase. Between 13% and 38% of the 125I injected was recovered from duodenal juice aspirated continously over 300 minutes. In contrast, less than 1% of the 131I-albumin injected was recovered. When bile and pure pancreatic juice were collected at endoscopic retrograde cholangiopancreatography after intravenous 125I-trypsin in a fourth subject 125I radioactivity was found to be secreted via both these routes. After 125I-trypsin infusion into the duodenum 11% of the total dose was found to be present in the circulation after 75 minutes. These results support the concept that recirculation of trypsin exists in man.