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Objective: To analyze the time points and levels of the expression of adhesion molecules in the pancreas and lung in pancreatitis of different severities, and to assess whether treatment with a monoclonal antibody against intercellular adhesion molecule-1 (ICAM-1) can reduce local and systemic complications., Background: The outcome of severe acute pancreatitis relates to its pulmonary and septic complications. Leukocyte adhesion and infiltration, both mediated by ICAM-1, are central events in the pathogenesis of necrotizing pancreatitis., Methods: Expression of ICAM-1 at different time points was assessed by immunohistochemistry and Western blot analysis in pancreas and lungs from rats with mild edematous or severe necrotizing pancreatitis. ICAM-1 expression was correlated with leukocyte infiltration and histologic changes. The possible therapeutic effect of monoclonal antibodies against ICAM-1 was assessed by measuring pancreatic and lung injury., Results: In edematous pancreatitis, increased ICAM-1 expression in pancreas was evident by 6 hours but did not occur in lung. In contrast, ICAM-1 was upregulated at 3 hours in the pancreas and at 12 hours in lung in necrotizing pancreatitis. Increased expression of ICAM-1 preceded leukocyte infiltration. Treatment of severe necrotizing pancreatitis with monoclonal antibodies against ICAM-1 decreased both local pancreatic injury and systemic lung injury compared with untreated controls., Conclusions: Upregulation of ICAM-1 and subsequent leukocyte infiltration appear to be significant mediators of pancreatic and pulmonary injury in pancreatitis, and both the onset and extent correlate with severity. The time course should permit effective prevention of tissue damage by treatment with ICAM-1 antibodies.

Objective: The purpose of the study was to determine the prevalence of activating K-ras mutations in the pancreas of patients with intraductal papillary mucinous tumors (IPMT) and to analyze their relation to the degree of site-specific histopathologic abnormality., Background: Intraductal papillary mucinous tumors of the pancreas have a biologic behavior that is significantly different from pancreatic ductal adenocarcinoma. Activating K-ras mutations, which may be important events in a multistage process of carcinogenesis, have been reported in IPMT., Methods: Forty-six different histologic specimens (comprising normal pancreatic ducts, hyperplasia, low-grade dysplasia, high-grade dysplasia-carcinoma in situ, and carcinoma) from 16 patients with IPMT and 9 specimens from patients with pancreatic ductal adenocarcinomas were designated by a pathologist. Genomic DNA was extracted from paraffin-embedded tissue sections after microdissection. The K-ras gene was amplified by polymerase chain reaction and subjected to DNA sequencing., Results: The K-ras mutations were detected in at least one specimen in 13 (81.2%) of 16 patients with IPMT. All mutations were found in codon 12. No codon 13 mutations were detected. The relative frequency of K-ras mutations in the different stages of IPMT was 16.7% in normal epithelium and papillary hyperplasia, 28.6% in low-grade dysplasia, and 57.1% in high-grade dysplasia-carcinoma in situ and invasive carcinoma. The K-ras mutations were detected in 6 (66%) of 9 pancreatic ductal adenocarcinomas., Conclusions: The K-ras codon 12 point mutations are as frequent in IPMT as in ductal adenocarcinoma. A stepwise increase in the frequency of codon 12 mutations correlated with the stage of neoplastic evolution to cancer. This finding is consistent with an important role of K-ras gene mutations in the transformation from normal epithelium to invasive carcinoma in the majority of patients with IPMT.

Objective: The purpose of the study is to review a single institutional experience with mucinous ductal ectasia (MDE) and intraductal papillary neoplasms (IPNs) and to compare the clinicopathologic features of the two groups of tumors., Summary Background Data: Mucinous ductal ectasia and IPNs represent newly recognized categories of pancreatic exocrine tumors, previously confused with pancreatic cystic neoplasms. The natural history of MDE and IPN is not well understood, and it is unclear whether MDE and IPN represent two distinct tumors or the same clinicopathologic entity., Methods: The authors reviewed the clinical presentation, treatment, histopathology, and outcomes of 23 patients diagnosed with MDE or IPN at their institution over the past 6 years., Results: The mean age at presentation for the cohort of patients with MDE and IPN was 62.5 years. The prevalence of abdominal pain was 75%, jaundice 25%, weight loss 42%, steatorrhea 37.5%, diabetes 37.5%, and history of pencreatitis 29%. Serum CA 19-9 levels ranged from 0 to 5350 units/mL with high levels reflecting advanced disease. There were no significant differences between MDE and IPN with respect to these parameters. Both MDE and IPN comprised papillary villous epithelial neoplasms involving the main and large pancreatic ducts. The tumors ranged from a few millimeters in size to panductal and were distinguished easily from cystic neoplasms in all cases. Invasive carcinoma was present in 11 (46%) of 24 patients, carcinoma in situ in an additional 10 (42%) of 24 patients, and low grade dysplasia in the remaining 3 (12%) of 24 patients. Mucinous ductal ectasia and IPN differed histopathologically only in degree of mucin secretion and tumor location. Mucinous ductal ectasia, but not IPN, was characteristically mucin-hypersecreting and more frequently involved the head of the gland than did IPN (11/16 vs. 1/8 p < 0.04). All patients were explored surgically and 20 (83%) of 24 of the tumors were resectable with frozen section control of the duct margins (9 pancreatoduodenectomies, 4 distal pencreatectomies, 7 total pancreatectomies). Despite the 88% prevalence of cancer, the overall survival at a mean follow-up of 21 months was 13 (87%) of 15 for MDE and 5 (71%) of 7 for IPN., Conclusions: Intraductal papillary neoplasms with or without MDE represent a spectrum of main duct papillary tumors ranging from adenoma to carcinoma with differing amounts of extracellular mucin production. Malignant IPNs with or without MDE typically exhibit extensive intraductal growth but are slow to invade the periductal tissues and slow to metastasize. The majority of patients with these tumors have resectable disease and a favorable prognosis; endoscopic therapy is inappropriate. The encompessing term intraductal papillary-mucinous tumors is appropriate.

Background: Calcium infusion and hypotension have been described as the most important risk factors for pancreatic injury after cardiopulmonary bypass., Methods: Rats were randomly allocated to three experimental groups undergoing either sham operation and saline infusion (Control, n = 30), hemorrhagic reduction of mean arterial pressure to 30 mmHg for 30 min alone (hypotension, n = 51), or hypovolemic hypotension followed by bolus infusion of CaCl2 (200 mg.kg-1; hypercalcemia, n = 85). Serum ionized calcium, amylase activity, trypsinogen activation peptide in pancreatic tissue homogenates, pancreatic wet/dry weight ratio, histologic changes, and mortality were assessed for 24 h., Results: Control rats showed no significant changes of any parameter throughout the experiments. In contrast, hypotension significantly increased serum amylase (P < 0.001), tissue trypsinogen activation peptide (P < 0.01), wet/dry weight ratio (P < 0.001), and histologic scores for edema (P < 0.001) and pancreatic necrosis (P < 0.05). Subsequent CaCl2 administration transiently increased [Ca2+] (P < 0.001) with the concentration rapidly returning to baseline within 3 h. That infusion of CaCl2 further increased amylase (P < 0.05), tissue trypsinogen activation peptide (P < 0.05), wet/dry weight ratio (P < 0.001), and histologic evidence of pancreatic edema (P < 0.05) and acinar necrosis (P < 0.05) when compared with hypotension alone. Whereas all Control animals survived the experiments, 22% (P < 0.05) and 47% (P < 0.05 vs. hypotension) of animals died in the hypotension and hypercalcemia groups, respectively., Conclusions: Temporary hypotension alone causes ectopic trypsinogen activation and lethal acute pancreatitis. Super-imposed hypercalcemia significantly aggravates hypotension-induced pancreatic injury and mortality in rats.

Cystic lesions of the pancreas include inflammatory pseudocysts, serous cystadenomas, and mucinous tumors, some of which are malignant. Preoperative clinical and radiological parameters are unreliable and may result in incorrect diagnosis and inappropriate treatment. Cyst fluid analysis for cytology, viscosity, carcino-embryonic antigen, CA 72-4, and CA 15-3 will distinguish mucinous from nonmucinous lesions and usually help in determining malignancy. Currently, there is no reliable method to differentiate inflammatory pseudocysts from serous cystadenomas. This distinction is important because the treatment of these two lesions is different; pseudocysts are either observed or drained, whereas serous tumors are usually resected. The tumor marker NB/70K was measured in aspirated cyst fluid from 13 inflammatory pseudocysts and 11 serous cystadenomas by a commercial immunoassay. Leukocyte esterase was measured using Chemstrip SG urine test strips and amylase and lipase on a routine chemistry analyzer. The cyst fluid NB/70K concentration was significantly higher in pseudocysts (mean, 555 U/ml; range, 42-1,926 U/ml) than in serous cystadenomas (mean, 12 U/ml; range 0-130 U/ml) and this difference was significant (p < 0.0002). Leukocyte esterase was detected in 7 of 11 pseudocysts but was absent in 10 of 10 serous tumors (p = 0.002). Amylase and lipase values were generally higher in pseudocysts but these markers were unreliable due to marked outliers. Cyst fluid NB/70K and leukocyte esterase are promising markers to help differentiate pseudocysts from serous tumors on percutaneous aspirates. When combined with previously reported cyst fluid parameters (amylase, lipase, cytology, and amylase isoenzymes), these two cystic lesions can be reliably distinguished.

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

Background: Bacterial infection of pancreatic necrosis is thought to be a major determinant of outcome in acute necrotizing pancreatitis. The determinants and possibilities for prophylaxis are unknown and difficult to study in humans., Objective: The time course of bacterial infection of the pancreas in a rodent model of acute necrotizing pancreatitis was characterized. The authors ascertained if there is a correlation with the degree of necrosis., Methods: Acute pancreatitis (AP) of graded severity was induced under sterile conditions by an intravenous infusion of cerulein (5 micrograms/kg/hr) for 6 hours (mild AP), or a combination of intravenous cerulein with an intraductal infusion of 10-mM glycodeoxycholic acid (0.2 mL for 2 min for moderate AP, 0.5 mL for 10 min for severe AP). Sham-operated animals (intravenous and intraductal NaCl 0.9%) served as controls. Ninety-six hours after induction, animals were killed for quantitative bacterial examination and histologic scoring of necrosis. In addition, groups of animals with severe AP were investigated at 12, 24, 48, 96, and 144 hours., Results: No significant pancreatic necrosis was found in control animals (0.3 +/- 0.1) or animals with mild AP (0.6 +/- 0.1) killed at 96 hours. Necrosis scores were 1.1 +/- 0.2 for animals with moderate AP and 1.9 +/- 0.2 for animals with severe AP. Control animals did not develop significant bacterial infection of the pancreas (> or = 10(3) CFU/g). At 96 hours, the prevalence of infection was 37.5% in animals with mild AP and 50% in animals with moderate AP. In animals with severe AP, infection of the pancreas increased from 33% in the first 24 hours to 75% between 48 and 96 hours (p < 0.05). The bacterial counts and the number of different species increased with time and was maximal (> 10(11) CFU/g) at 96 hours., Conclusion: Bacterial infection of the pancreas in rodent AP increases during the first several days, and its likelihood correlates with the severity of the disease. This model, which closely mimics the features of human acute pancreatitis, provides a unique opportunity to study the pathogenesis of infected necrosis and test therapeutic strategies.

Objective: The authors evaluated cyst fluid CA 72-4 as a tumor marker in the differential diagnosis of pancreatic cystic lesions., Summary Background Data: Pancreatic cystic lesions include inflammatory pseudocysts, serious cystadenomas, and mucinous tumors. Mucinous tumors can be further subdivided into mucinous cystadenocarcinomas and premalignant mucinous cystic neoplasms. The clinical and radiologic features of these lesions are unreliable to make a preoperative diagnosis of these diagnostically difficult lesions. Analysis of aspirated cyst fluid was proposed as an aid to making the preoperative differential diagnosis. Currently, a number of parameters have been reported as useful markers in cyst fluid aspirates, including the tumor markers carcinoembryonic antigen and CA 15.3, enzymes (amylase, lipase, and amylase isoenzymes), relative viscosity, and cytologic analysis. However, owing to the rarity of pancreatic cystic tumors, experience with cyst fluid analysis is limited. To define additional markers that might be useful in the differential diagnosis of pancreatic cysts, the authors measured the tumor-associated glycoprotein 72 (TAG-72) in aspirates from 19 pancreatic cystic lesions., Methods: Cyst fluid from 19 pancreatic cysts was obtained by needle aspiration. The tumor marker TAG-72 was measured by a commercial (CA 72-4) immunoassay., Results: Cyst fluid CA 72-4 levels in mucinous cystadenocarcinomas were markedly elevated (mean, 10,027 U/mL; range, 780 to 34,853 U/mL) compared with that in pseudocysts (mean, 3.8 U/mL; range, < 3 to 5.7 U/mL) and serous cystadenomas (mean and range, < 3 U/mL; p < 0.001). The level of CA 72-4 in benign mucinous cystic neoplasms was intermediate (mean, 44.2 U/mL; range, < 3 to 137 U/mL), but it was statistically different from either carcinomas (p = 0.009) or benign cysts (p < 0.001).

Pancreatic cystic lesions include inflammatory pseudocysts, benign serous tumors, and mucinous neoplasms, some of which are malignant. Clinical and radiologic indices are often inadequate to discriminate reliably among these possibilities. In an attempt to develop new preoperative diagnostic criteria to assist in decisions regarding therapy, the authors have performed cyst fluid analysis for tumor markers (carcinoembryonic antigen: CEA, CA 125, and CA 19.9), amylase content, amylase isoenzymes, relative viscosity, and cytology on 26 pancreatic cysts. The cases included nine pseudocysts, five serous cystadenomas, 4 mucinous cystic neoplasms, 7 mucinous cystadenocarcinomas, and one mucinous ductal adenocarcinoma with cystic degeneration. Carcinoembryonic antigen levels were high (> 367) in all benign and malignant mucinous cysts, but were low (< 23) in the pseudocysts and benign serous cystadenomas, an indication that CEA discriminates between mucinous and nonmucinous cysts (p < 0.0001). Values for CA 125 were high in all malignant cysts, low in pseudocysts, and variable in mucinous cystic neoplasms and serous cystadenomas. Levels of Ca 19.9 were nondiscriminatory. Cyst fluid amylase and lipase content were variable but were generally high in pseudocysts and low in cystic tumors. Amylase isoenzyme analysis was useful to differentiate pseudocysts from cystic tumors. Measurement of the relative viscosity in cyst fluid showed high (> serum viscosity) values in 89% of mucinous tumors and low values (< serum) in all pseudocysts and serous cystadenomas (p < 0.01). Cytologic analysis of cyst fluids was of limited value in differentiating pseudocysts from serous cystadenoma, but in seven of eight mucinous tumors provided useful diagnostic information and correctly classified three of five malignant tumors. The authors conclude that cyst fluid analysis can provide a preoperative classification of these diagnostically difficult lesions. The combination of viscosity, CEA, CA 125, and cytology can reliably distinguish malignant cystic tumors and potentially premalignant mucinous cystic neoplasms from pseudocysts and serous cystadenomas. Amylase content with isoenzyme analysis is useful to identify pseudocysts.