Serum Immunoreactive Trypsin Research Articles

Cystic fibrosis newborn screening: outcome of infants with normal sweat tests

Newborn babies positively screened for cystic fibrosis (CF) (high serum immunoreactive trypsin (IRT) with DNA analysis) are referred for a diagnostic sweat test, which may be normal (sweat chloride <30...

46 Delay in meconium emission: should it be considered a risk for cystic fibrosis?

Background: Ten to 15% of CF infants present with meconium ileus (MI), that sometimes can lead to intestinal malformation. Serum immunoreactive trypsin (IRT) levels may be normal and newborn screening (NBS) could be erroneously considered negative. In our CFNBS protocol newborn babies presenting problems with meconium passage (delay in meconium emission − MD − included) undergo sweat test also if IRT is negative Aim: The aim of this study is to investigate the incidence of CF in neonates with MI and MD to determine if infants with this last condition have to be submitted to CF diagnostic test. Patients and Method: A retrospective 5-year study examines neonates screened in our Center that presented problems in meconium passage, with regard to IRT values and CF diagnosis. Results: In a 5-year period (2006–2010) we screened 172,185 newborns and diagnosed 50 CF. Eigthy-two newborns were reported having some problems related to meconium passage: 13 were referred as MI (group 1), 7 as intestinal atresia (IA) (group 2), 62 as MD (group 3). In group 1 8/13 had IRT positive, 6/13 were diagnosed as CF and one of them had IRT normal value; 2 died without diagnosis. In group 2 6/7 had IRT negative, 2/7 had CF and one of them was IRT negative. In group 3 nobody out 62 had IRT positive, nor positive sweat test. Conclusion: In this series 12% of CF neonates presented with MI and/or IA, and 2 of them were IRT negative confirming that CF with MI and IA can have negative NBS. Delay in meconium pass is therefore, asscociated neither with positive screening nor with CF, suggesting that newborns with MD and IRT negative don’t require further analysis for CF.

47 CFTR gene mutations and the risk for developing a pancreatic cancer: is it only a consequence of chronic inflammation?

Background: Ten to 15% of CF infants present with meconium ileus (MI), that sometimes can lead to intestinal malformation. Serum immunoreactive trypsin (IRT) levels may be normal and newborn screening (NBS) could be erroneously considered negative. In our CFNBS protocol newborn babies presenting problems with meconium passage (delay in meconium emission − MD − included) undergo sweat test also if IRT is negative Aim: The aim of this study is to investigate the incidence of CF in neonates with MI and MD to determine if infants with this last condition have to be submitted to CF diagnostic test. Patients and Method: A retrospective 5-year study examines neonates screened in our Center that presented problems in meconium passage, with regard to IRT values and CF diagnosis. Results: In a 5-year period (2006–2010) we screened 172,185 newborns and diagnosed 50 CF. Eigthy-two newborns were reported having some problems related to meconium passage: 13 were referred as MI (group 1), 7 as intestinal atresia (IA) (group 2), 62 as MD (group 3). In group 1 8/13 had IRT positive, 6/13 were diagnosed as CF and one of them had IRT normal value; 2 died without diagnosis. In group 2 6/7 had IRT negative, 2/7 had CF and one of them was IRT negative. In group 3 nobody out 62 had IRT positive, nor positive sweat test. Conclusion: In this series 12% of CF neonates presented with MI and/or IA, and 2 of them were IRT negative confirming that CF with MI and IA can have negative NBS. Delay in meconium pass is therefore, asscociated neither with positive screening nor with CF, suggesting that newborns with MD and IRT negative don’t require further analysis for CF.

Persistent elevated tissue‐transglutaminase in cystic fibrosis

Persistent elevated tissue‐transglutaminase in cystic fibrosis

Endoscopic Ultrasound (EUS), Chronic Pancreatitis, and Pancreatic Cancer (PC) Precursors in High Risk Individuals

Endoscopic Ultrasound (EUS), Chronic Pancreatitis, and Pancreatic Cancer (PC) Precursors in High Risk Individuals

Immunoreactive trypsin levels in neonates with meconium ileus

Serum immunoreactive trypsin (IRT) is used as a screening test for cystic fibrosis (CF) in neonates in many countries. Variations in IRT levels are observed in healthy and cystic neonates within the first few weeks of life. Fifteen percentage of CF neonates present with meconium ileus (MI). We hypothesised that there may be differences in serum IRT levels in cystic babies with simple and complicated MI. The aim of this study was to investigate the serum levels of IRT in neonates with CF presenting with MI. IRT levels were sequentially measured in neonates (n = 29) with CF with intestinal obstruction due to simple or complicated MI. These were compared to levels obtained from non-cystic neonates/controls admitted with a variety of other intra-abdominal pathologies (n = 49) IRT levels were significantly higher in the CF-MI group than the non-cystic controls (P < 0.001). There was no statistical difference in IRT levels between the simple or complicated MI groups. In the MI group there was no statistical difference between those who required operation, no difference between the pre- and post-operative IRT levels and no significant relationship between IRT levels and birth weight or gestation. Serum IRT levels are significantly elevated in neonates with CF and MI compared with non-cystic, non-MI neonates. The results of this observational study highlight that a single raised level of IRT in a neonate should prompt the analysis for CF regardless of any underlying surgical pathology.

Pancreatic volume in type 1 and type 2 diabetes mellitus.

We measured pancreatic volume (PV) using helical computed tomography (CT) in 26 patients with type 1 diabetes mellitus (DM), 29 patients with type 2 DM, and 22 healthy individuals. We also evaluated the relationship between PV and the body surface area (BSA), established the pancreatic volume index (PVI) by dividing PV by BSA to correct PV for the body build, and examined its relationships with the duration of illness, serum C-peptide immunoreactivity level (CPR), and serum immunoreactive trypsin level (IRT). BSA and PV were correlated significantly (p<0.0001, r=0.645) in healthy individuals, and they were correlated also in the diabetic patients (p=0.0023, r=0.563 in type 1 DM; p=0.0346, r=0.392 in type 2 DM). PV was significantly smaller in the type 1 DM group than in the healthy group and type 2 DM group (p<0.001 for both). PVI was also significantly smaller in the type 1 DM group than in the healthy group and type 2 DM group (p<0.001 for both). PVI and IRT were significantly correlated in both DM groups (p<0.0001, r=0.732 in type 1 DM; p=0.0469, r=0.371 in type 2 DM). PVI was not correlated with the duration of illness or CPR. Helical CT was useful for the measurement of the pancreatic volume, and the pancreatic volume was reduced particularly in the patients with type 1 DM. A strong correlation was observed between PV and exocrine pancreatic function in type 1 DM, but the correlation between PV and exocrine pancreatic function was weak in type 2 DM.

Tolbutamide causes a modest increase in insulin secretion in cystic fibrosis patients with impaired glucose tolerance

We examined the effect of intravenous (IV) tolbutamide administration on glucose and hormone levels in cystic fibrosis (CF) patients with impaired first-phase insulin secretion and oral glucose tolerance (oral glucose tolerance test [OGTT]) and compared them with CF patients with only an impaired first-phase insulin secretion and healthy control subjects. Five CF patients with an impaired OGTT, ie, a serum glucose value of 7.8 mmol/L or greater 120 minutes after an oral glucose load (group I), five CF patients with a normal OGTT, ie, a serum glucose not exceeding 7.8 mmol/L 120 minutes after oral glucose (group II), and five healthy control (CON) subjects underwent IV glucose tolerance tests with glucose alone (IVGTT) and glucose administered in conjunction with tolbutamide ([IVTTT] 25 mg/kg; maximum dose, 1 g). Serum glucose levels were measured using the glucose oxidase method; insulin, C-peptide, and glucagon levels were measured by the double-antibody radioimmunoassay (RIA) technique. Serum immunoreactive trypsin (IRT) and hemoglobin A 1 (HbA 1) levels and height and weight were measured for each subject, and in addition, pulmonary function was assessed in those with CF. There were no significant differences in the area under the curve (AUC) for glucose or glucagon levels or the serum glucose disappearance rate ( k value) between group I, group II, or CON subjects during the IVGTT. First-phase insulin and C-peptide secretion was abnormal during IVGTT and IVTTT in the CF groups: in group I it was severely impaired, whereas in group II it was between group I and CON values. During the IVTTT serum glucose levels and glucose k values were not significantly altered in any of the three groups as compared with the IVGTT. Tolbutamide administration significantly increased the AUC for serum insulin in group II and CON subjects as compared with IVGTT values (67% and 135%, respectively, P < .05), with a modest ( P > .05) increase in group I levels (28%). Likewise, there were significant increases in the AUC for C-peptide with IVTTT in group II (49%, P < .05) and CON subjects (58%, P < .01), with a lesser increase in group I (21%). The glucagon AUC was not significantly altered in IVTTT as compared with IVGTT in any group. These observations suggest that endocrine function in CF subjects is a continuous spectrum from those with diabetes mellitus to normals. Only long-term studies will determine if the residual secretion of insulin in response to oral sulfonylurea is of clinical importance.

Cystic fibrosis screening in neonates — measurement of immunoreactive trypsin and direct genotype analysis for ΔF508 mutation

This study investigated the clinical usefulness of screening for cystic fibrosis (CF) in 19,992 newborns, over 39 months, in an Austrian population. Immunoreactive serum trypsin (IRT) determination was followed by sweat chloride analysis (sweat test) to establish diagnosis. In a retrospective analysis covering 6 months of the study period, individuals who were considered to be at risk after IRT estimation (n = 22) were analysed for delta F508 mutation, using a new method of DNA extraction from the initial dried blood specimens. A total of 119 infants (0.6%) had values greater than 750 ng trypsin/ml whole blood. In 88 babies sweat tests were performed, leading to the diagnosis of CF in 11 cases. One patient was not initially identified by screening but was later discovered due to his clinical status. Three infants were noted to carry the delta F508 mutation (1 homozygous, 2 heterozygous). Two of these babies already had CF. The second heterozygote was a carrier. A highly efficient three tier screening strategy is presented in which IRT estimation, determination of delta F508 status and sweat chloride testing could lead to a high sensitivity analysis of this population.

Serum pancreatic stone protein in pancreatic diseases.

Serum pancreatic stone protein (PSP) was determined in sera of pancreatic and nonpancreatic diseases using enzyme immunoassay specific to human PSP to study the diagnostic and pathophysiological significance of PSP. Serum PSP in acute pancreatitis (mean +/- SD = 1075.4 +/- 2849.1 ng/mL, n = 33) was significantly higher than that in controls (78.6 +/- 31.8 ng/mL, n = 37, p < 0.01), chronic pancreatitis (156.8 +/- 82.8 ng/mL, n = 32, p < 0.05), and pancreatic cancer (148.468.8 ng/mL, n = 26, p < 0.05). No significant difference was found between noncalcified and calcified chronic pancreatitis. Serum PSP levels were significantly higher in chronic renal failure under hemodialysis (1796.0 +/- 1492.9 ng/mL) than in other diseases such as peptic ulcer, liver cirrhosis, gallstone, and diabetes mellitus. Low but significant correlation was obtained between serum PSP and serum immunoreactive trypsin (r = 0.22, p < 0.05). Increased serum PSP levels in acute pancreatitis and chronic renal failure suggest that serum PSP levels reflect reflex from pancreatic secretion, release from damaged pancreatic acinar cells, or retention in circulation, and can be useful for diagnosis of acute pancreatitis, but not chronic calcified pancreatitis.

Effect of Environmental and Genetic Factors on Serum Immunoreactive Trypsin in Insulin-dependent Diabetes Mellitus

Effect of Environmental and Genetic Factors on Serum Immunoreactive Trypsin in Insulin-dependent Diabetes Mellitus

Exocrine Pancreatic Function (Serum Immunoreactive Trypsin, Fecal Chymotrypsin, and Pancreatic Isoamylase) in Indian Diabetics

Forty-nine patients with tropical calcific pancreatitis (TCP), 51 insulin-dependent diabetics (IDDMs), 87 non-insulin-dependent diabetics (NID-DMs), and 66 nondiabetic controls were studied to evaluate their exocrine pancreatic function by measurement of serum immunoreactive trypsin (IRT, normal for white caucasians from the U.K. of 140-414 micrograms/L), pancreatic isoamylase (PIA, normal of 35-125 U/L), and fecal chymotrypsin (FCT, normal of greater than 6.6 u/g). The majority of patients were studied within 1 year of diagnosis. TCP subjects included 7 nondiabetics, 6 with impaired glucose tolerance (IGT-TCP), and 36 diabetics [fibrocalculous pancreatic diabetes (FCPD)]. There was evidence of active pancreatitis (IRT greater than 800 micrograms/L) and partial preservation of function in nondiabetic TCP subjects [median IRT of 220 micrograms/L (range of 102-1,360 micrograms/L), FCT of 2.2 u/g (range 0.7-12.8 u/g)] and also in IGT-TCP subjects [IRT of 370 micrograms/L (range of 30-1,360 micrograms/L), FCT of 4.2 u/g (range of 1-38 u/g)]. FCPDs showed severely diminished exocrine function [IRT of 50 micrograms/L (range of 0-184 micrograms/L), FCT of 0.23 u/g (range of 0-10.4 u/g)]; none showed IRT greater than 800 micrograms/L. IDDMs and NIDDMs also showed diminished exocrine pancreatic function in approximately 30 and approximately 10%, respectively. Controls showed a wide range of IRT and FCT concentrations; IRT concentrations tended to be higher than those reported in white Caucasians from the U.K. Three controls, one IDDM, and two NIDDMs showed "pancreatic" IRT concentrations in the absence of symptoms. PIA concentrations were diminished in FCPD but were similar in IDDM and NIDDM subjects compared to controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Peritoneal absorption of pancreatic enzymes in bile‐induced acute pancreatitis in dogs

To clarify the contribution of peritoneal absorption of enzyme-rich exudate to the persistent elevation of serum amylase in bile-induced pancreatitis in dogs, serum amylase, lipase and immunoreactive trypsin (IRT) levels were measured during 24 h after induction of pancreatitis with and without peritoneal lavage. The basal level of serum amylase activity (m +/- s.e. = 1291 +/- 111 U/L) reached a plateau at 30 min (2688 +/- 185) after induction of pancreatitis and continued to rise until 24 h (7201 +/- 424). This persistent amylase elevation could be reduced significantly by peritoneal lavage. Serum IRT rose to a peak (378 +/- 103 ng/mL) at 30 min from the basal (20 +/- 5), then decreased until 3 h (211 +/- 34) and maintained a consistent level thereafter. Serum lipase elevation took an intermediate course between the levels of serum amylase and IRT. Intraperitoneal injection of 5 mL pancreatic juice could reproduce similar elevations to those of the respective enzymes, except lipase, seen in pancreatitis. These results suggest that transperitoneal absorption of pancreatic enzymes contributes to the elevation in serum enzymes levels and that rates of peritoneal absorption and serum disappearance differ from enzyme to enzyme.

Prevention of experimental acute pancreatitis by intraduodenal trypsin inhibitor in rat

To confirm that trypsin activity is a most important initiating factor in closed duodenal loop pancreatitis in rats, we observed the course of acute pancreatitis when trypsinogen activation was inhibited by intraduodenal infusion of a potent synthetic trypsin inhibitor (TI, nafamostat mesilate) but the other conditions were left unchanged. Intraduodenal and intrapancreatic trypsinogen activation was inhibited for 16 hr after the intraduodenal infusion of the inhibitor, although elevation of serum amylase and immunoreactive trypsin and pancreatic trypsinogen remained similar both in the TI and control groups. The mortality decreased from 44% (control) to 4% (TI) at 48 hr after establishing the model. Active trypsin in duodenal reflux is an initiating factor for further development of acute pancreatitis in the closed loop model, and inhibition of the initial activation of trypsinogen has a favorable effect on acute pancreatitis even if other deleterious factors remain unchanged.

Behaviour of serum immunoreactive trypsin after serum activation by enterokinase in normal and cystic fibrosis patients. Evidence of a trypsin-α 1-proteinase inhibitor complex in some cystic fibrosis patients

Serum immunoreactive trypsin (IRT) concentrations are elevated in newborn children with cystic fibrosis (CF) and subsequently fall, in most cases, to values below normal. To evaluate the molecular form(s) of IRT present in serum, we have performed serum activation by enterokinase and have measured serum IRT before and after activation. This approach is based on the postulate that enterokinase converts trypsinogen into trypsin, and this trypsin would then be mainly trapped by α 2-macroglubulin, thus escaping the assay. This assumption was confirmed in the 28 controls studied, where the mean percentage (±S.D.) of IRT recovery after serum activation was 13.7 ± 2.9. Previous inhibition of α 2-macroglobulin by methylamine raised the recovery over 85%, confirming that most of the serum IRT present in controls was in the form of trypsinogen. Identical results were obtained in the serum of 10 obligate heterozygotes and in 57 out of 80 CF patients. In 23 CF patients the mean percentage of IRT recovery after serum activation was 41.6 ± 17.6. Gel-filtration studies were performed on the sera of the CF patients showing an abnormal increase in the IRT recovery after serum activation. We could demonstrate that IRT was distributed in two fractions: one eluted with the M r 25 000 protein as usually found in controls and other CF sera, and the other eluted with the M r 75 000 protein corresponding to a complex of trypsin with α 1-proteinase inhibitor. These results show that, in these sera, active trypsin has been directly released in blood. These findings suggest that in some patients with CF, subclinical attacks of acute pancreatitis may occur.

PANCREATIC ENZYMES IN SERUM AND URINE AS INDICATORS OF PANCREATIC ALLOGRAFT REJECTION IN THE PIG

We have studied the reliability of serum and urinary immunoreactive anionic trypsin (irAT), immunoreactive cationic trypsin (irCT), and amylase activity as rejection indicators in a porcine whole-organ pancreaticoduodenal transplantation model with exocrine drainage to the urinary bladder. No immunosuppressive therapy was administered. Exocrine tissue integrity and function were studied by measuring these enzymes in serum and urine. Urine analyses were performed before and after an intravenous secretin-cholecystokinin stimulation. Of 16 transplanted pigs, 10 became diabetic during a 2-week observation period while six remained normoglycemic. Serum irAT was found to predict rejection while serum amylase and serum irCT did not. An increase in irAT was seen in rejecting pigs preceding the onset of hyperglycemia by a median of 2 days (range 1-9). Secretion of irAT into the urine remained high during the observation period in nondiabetic pigs while the output declined in diabetic pigs. This decline was seen after the increase in serum irAT. When urine was sampled after a secretin-CCK stimulation, these findings were clearly evident, but less unequivocal results were obtained without stimulation. IrAT measurements were superior to measurements of amylase, irCT, or bicarbonate. Thus rejection of a pancreatic allograft was first indicated by a temporary rise in serum immunoreactive anionic trypsin, probably due to the onset of tissue damage. Thereafter, stimulated urinary enzyme output levels gradually declined and finally, hyperglycemia developed.

Exocrine Pancreatic Function in Sjögren's Syndrome

Pancreatic function testing was carried out in 19 patients with Sjögren's syndrome (SS) (nine primary type, ten secondary) by the N-benzoyl-tyrosil-p-aminobenzoic acid (PABA) test, serum immunoreactive trypsin (IRT) levels, and stool fat measurements to evaluate the incidence and type of exocrine pancreatic alterations in this disease. Exocrine pancreatic impairment was found to be present in 63% of the patients. Three types of secretory patterns were observed: (1) normal PABA test results and normal IRT levels (37% [7/19] of the patients); (2) normal PABA test results and elevated IRT levels (42% [8/19]; and (3) low PABA test results and elevated IRT levels (21% [4/19]), including two patients with steatorrhea. Functional pancreatic impairment tended to be more severe in patients with longer disease duration and it was related to the degree of alteration of salivary flow but not to labial salivary gland histologic changes or the type of SS. Inasmuch as hypertrypsinemia was the common marker of pancreatic dysfunction in all patients, we suggest a periodic measurement of serum IRT levels in the follow-up of patients with SS to detect early stages of pancreatic involvement.

Increased phosphoinositide breakdown by phospholipase C in erythrocyte membranes from patients with cystic fibrosis

Phosphoinositide phospholipase C activity has been measured in erythrocyte membranes from age-matched control and CF subjects. Inositol phospholipids were labelled with [ 3H]myo-inositol and control experiments demonstrated that the [ 3H]-labelled products released by incubation of membranes with Ca 2+ were derived specifically from erythrocytes (a) by purification of erythrocytes on cellulose columns, (b) by demonstration that the phospholipase C activity was inhibited by 10 mmol/l neomycin but not by 1 mmol/l p-methylsulphonylfluoride. The [ 3]H]-labelled products were shown to be inositol phosphates by their elution from anion-exchange columns. Membranes from CF patients showed increased phospholipase C activity compared to controls which did not correlate with the degree of [ 3H]inositol labelling of the membranes, with pancreatic function as assessed by serum immunoreactive trypsin or with medications taken by the patients.

Renal Tubular Dysfunction in Pancreatic Cancer and Chronic Pancreatitis

Urinary excretion of alpha-glucosidase (AGL), gamma-glutamyltransferase (GGT) and ribonuclease (RNase), and serum amylase and immunoreactive trypsin (IRT) were determined in 38 control subjects, 48 patients with pancreatic cancer, 77 with chronic pancreatitis and 47 with extrapancreatic diseases in order to ascertain the presence of a renal tubular damage and to investigate its etiology. A significantly increased frequency of pathological results for all urinary enzymes was documented in the various groups of patients as compared to controls. Significant correlations were detected among AGL, GGT and RNase. Considering the subjects as a whole, GGT and RNase excretions correlated with serum IRT and amylase; the two urinary enzymes were found to be higher when jaundice was present. In chronic pancreatic disease enzymuria was related to increased serum pancreatic enzymes; in extrapancreatic diseases it was associated to hyperbilirubinemia. The vast majority of patients with pancreatic cancer and elevated urinary enzymes presented hepatic metastases and/or jaundice. We can conclude that an anatomical and functional tubular impairment is detectable in some patients with chronic pancreatic and extrapancreatic diseases. Tubular damage seems to least in part to be related to pancreatic inflammation and necrosis in chronic pancreatic disease, while jaundice may be found to play an important role in diseases of the hepatobiliary tract. In pancreatic cancer, liver dysfunction (presence of liver metastases and/or extrahepatic cholestasis) also appears to be involved in altering tubular cells.

Serum immunoreactive trypsin in tropical pancreatic diabetes syndrome.

Fifteen patients with tropical pancreatic diabetes syndrome (TPDS), 16 insulin-dependent diabetics (IDD), 27 non-insulin-dependent diabetics (NIDD) and 14 normal subjects, all from India, were investigated for markers of beta-cell (C-peptide) and exocrine (immunoreactive trypsin; IRT) reserve. IRT and C-peptide concentrations were the lowest in TPDS, lower than normal in IDD, and not significantly different from normal in NIDDs. There was a highly significant correlation (rs = 0.93; P less than 0.0001) between IRT and C-peptide (measured in 50% of patients and controls) concentrations when all diabetic groups were combined. Such a correlation was absent when TPDS patients were considered in isolation, largely because of the markedly low IRT concentration. Fourteen of 15 patients (93%) with TPDS had subnormal IRT concentrations, of which 11 had IRT values of less than 50 micrograms/L. These IRT values are similar to those previously reported in cystic fibrosis. Only 6 of 16 IDDs (38%) had subnormal IRT concentrations, of which only one was below 50 micrograms/L. These data suggest that exocrine pancreatic reserve is markedly diminished in TPDS and that a subnormal IRT concentration may be a useful biochemical marker for this form of diabetes.