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Background and Aims: Neoadjuvant chemoradiation (nCRT) followed by curative surgery has gained acceptance as the therapy of choice in locally advanced rectal cancer. This prospective study evaluates the effect of nCRT on postoperative anorectal function and continence., Patients and Methods: Group A consisted of 12 patients (59.8 +/- 11.9 years, male:female = 8:4) who received nCRT (5-FU, CPT-11. 45 + 5.4 Gy boost) before surgery and Group B of 27 patients (61.9 +/- 10.6 years, male:female = 16:11) who were treated by surgery alone. All patients received a questionnaire to evaluate stool continence and anorectal function before as well as after surgery. Anorectal function was further analyzed by perfusion manometry pre- and postoperatively., Results: Preoperatively, none of the patients had signs or symptoms of fecal incontinence, and preoperative measurements showed values within normal limits. Postoperatively, fecal continence was impaired in both groups, but no significant difference was found between patients with or without nCRT. Anorectal manometry revealed an impairment of anorectal function after low anterior resection regardless of the treatment regime., Conclusion: nCRT does not impair anorectal function and fecal continence. The deterioration of continence and anal sphincter function after sphincter preserving surgery is solely caused by the surgical procedure.

Purpose: The novel method of organ-specific drug application we present here is unilateral chemoembolization of the lung by injecting the pulmonary artery with degradable starch microspheres and cytotoxic drugs to improve tumor control in lung metastases., Experimental Design: In a solitary metastasis rat model (CC531 adenocarcinoma), we studied the clinical and histological tumor response as well as subacute toxicity of the lung. Fourteen days after tumor induction, animals were randomized into five groups. Groups I and II served as controls. Group III received carboplatin i.v. (45 mg/kg). Isolated lung perfusion with buffered starch solution and carboplatin (15 mg/kg) was installed in group IV. Chemoembolization with carboplatin (15 mg/kg) was performed in group V., Results: Seven days later, the difference in the tumor volume before and after treatment was +422 mm(3) (+/-226) in group I, +697 mm(3) (+/-423) in group II, +70 mm(3) (+/-31) in group III, -8 mm(3) (+/-17) in group IV, and -17 mm(3) (+/-16) in group V (P < 0.05 groups IV and V versus groups I, II, and III). No pleural spread was observed in groups IV and V. Histologically, the area of tumor necrosis was largest in group IV. Mild alveolar cell hyperplasia, pulmonary edema, and hemorrhage without subacute fibrotic changes were noted in all groups., Conclusion: This is the first study to perform chemoembolization of the lung. Compared with i.v. therapy, chemoembolization was more effective without serious toxicity. Its efficacy was comparable with that of isolated lung perfusion but less stressful for a possible clinical application.

Clinically and biologically relevant animal models are mandatory to further evaluate both the pathophysiology and novel strategies for diagnosis and treatment of exocrine pancreatic cancer. This review briefly summarizes the features of human pancreatic cancer in order to define requirements for animal models of the disease. The described model systems in rodents include pancreatic cancer induced by chemicals, pancreatic cancer in transgenic, and immunodeficient animals.

Background: Capillary leakage with fluid loss into the third space contributes to many of the early systemic complications in severe acute pancreatitis. There has been increasing interest in endothelin as one of the factors affecting capillary permeability., Aim: To elucidate further the role of endothelin in the development of capillary leakage in acute pancreatitis by investigating the effect of exogenous endothelin administration and endothelin receptor blockade in sham operated animals and two models of acute pancreatitis., Methods: Determination of capillary permeability in the pancreas and colonic mucosa by quantifying extravasation of fluorescein labelled dextran using a novel computer assisted video image analysis system., Results: Pancreatic and colonic capillary permeability increased stepwise from mild to severe acute pancreatitis. Endothelin increased pancreatic and colonic capillary permeability in healthy animals and animals with mild acute pancreatitis but had no additional adverse effect in severe acute pancreatitis. Endothelin receptor blockade decreased pancreatic capillary permeability in sham operated rats but had no effect on the colon. In mild and severe acute pancreatitis, endothelin receptor blockade stabilised increased capillary permeability in both the pancreas and colon., Conclusions: Endothelin plays an important role in mediating capillary permeability in the pancreas. In severe pancreatitis, it increases capillary permeability even outside the pancreas, thereby contributing to capillary leakage. Endothelin receptor blockade significantly reduces capillary permeability in acute pancreatitis both in and outside the pancreas, suggesting a therapeutic approach to counteract capillary leakage in severe acute pancreatitis.

Objective: To evaluate the effect of a new endothelin receptor antagonist (ET-RA) on the course of severe experimental pancreatitis., Background: Endothelin-1 has been shown to reduce regional blood flow in various organs, including the pancreas, and to aggravate cerulein-induced mild pancreatitis., Methods: Acute necrotizing pancreatitis (ANP) was induced in rats by standardized intraductal bile acid infusion and cerulein hyperstimulation. Serum trypsinogen activation peptides (TAP) were measured to verify comparable disease severity. Starting 6 hours after the onset of ANP, animals randomly received either saline or the new ET-RA LU-135252. Monitoring included cardiorespiratory parameters, urine output, hematocrit, and TAP levels. After 24 hours, animals were relaparotomized to determine pancreatic capillary blood flow and to assess the amount of free intraabdominal fluid and acinar cell necrosis. Survival was determined in a second set of experiments on 24 animals observed for 48 hours after pancreatitis induction and treatment with either normal saline or ET-RA., Results: Comparable TAP increases confirmed equally severe ANP in both groups before treatment. Treatment with ET-RA significantly reduced the mortality rate, from 50% in untreated animals to 8%. Improved survival was associated with significantly decreased hematocrit, improved urinary output, decreased ascites, and increased pancreatic capillary blood flow. There were no significant differences in plasma TAP and acinar cell injury in the surviving animals of the two treatment groups., Conclusion: Therapy with the new ET-RA reduces the early mortality rate in experimental ANP, probably by reducing fluid sequestration and improving microcirculation.

Objective: The authors test antibiotic strategies aimed at either mitigating bacterial translocation from the gut or delivering antibiotics specifically concentrated by the pancreas for prevention of early secondary infection after acute necrotizing pancreatitis., Background: Infection currently is the principal cause of death after severe pancreatitis. The authors have shown that the risk of bacterial infection correlates directly with the degree of tissue injury in a rodent model of pancreatitis. Bacteria most likely arrive by translocation from the colon., Methods: Severe acute necrotizing pancreatitis was induced in rats by a combination of low-dose controlled intraductal infusion of glycodeoxycholic acid superimposed on intravenous cerulein hyperstimulation. At 6 hours, animals were randomly allocated to five treatment groups: controls, selective gut decontamination (oral antibiotics and cefotaxime), oral antibiotics alone, cefotaxime alone, or imipenem. At 96 hours, surviving animals were killed for quantitative bacterial study of the cecum, pancreas, and kidney., Results: The 96-hour mortality (35%) was unaffected by any treatment regimen. Cecal gram-negative bacteria were significantly reduced only by the oral antibiotics. Pancreatic infection was significantly reduced by full-gut decontamination and by imipenem, but not by oral antibiotics or by cefotaxime alone. Renal infection was reduced by both intravenous antibiotics., Conclusions: Early pancreatic infection after acute necrotizing pancreatitis can be reduced with a full-gut decontamination regimen or with an antibiotic concentrated by the pancreas (imipenem) but not by unconcentrated antibiotics of similar spectrum (cefotaxime) or by oral antibiotics alone. These findings suggest that 1) both direct bacterial translocation from the gut and hematogenous seeding interplay in pancreatic infection while hematogenous seeding is dominant at extrapancreatic sites and 2) imipenem may be useful in clinical pancreatitis.

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: Previous reports demonstrated that radiographic contrast medium, as used in contrast-enhanced computed tomography, increases acinar necrosis and mortality in experimental pancreatitis. The authors studied the possibility that these changes may be related to an additional impairment of pancreatic microcirculation., Methods: Fifty Wistar rats had acute pancreatitis induced by intraductal glycodeoxycholic acid (10 mmol/L for 10 min) and intravenous cerulein (5 micrograms/kg/hr for 6 hrs). After rehydration (16 mL/kg), pancreatic capillary perfusion was quantified by means of intravital microscopy at baseline before intravenous infusion of contrast medium (n = 25) or saline (n = 25), and 30 and 60 minutes thereafter. In addition to total capillary flow, capillaries were categorized as high- or low-flow (> or < 1.6 nL/min)., Results: Pancreatic capillary flow did not change in either high- or low-flow capillaries after saline infusion. However, contrast medium infusion induced a significant decrease of total capillary flow (p < 0.001). Analysis according to the relative flow rate revealed that this was primarily because of a significant additional reduction of perfusion in low-flow capillaries (p < 0.0001). Furthermore, complete capillary stasis was observed in 15.9 +/- 3.4% after contrast medium as compared with 3.2 +/- 1.2% after saline infusion (p < 0.006)., Conclusion: Radiographic contrast medium aggravates the impairment of pancreatic microcirculation in experimental necrotizing 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.

Background/aims: Contrast-enhanced computed tomography (CECT) is used to show areas of decreased pancreatic perfusion in severe acute pancreatitis (AP). To evaluate possible adverse effects of the contrast medium (CM) on the course of AP, the impact of intravenous CM in AP of graded severity in the rat was studied., Methods: Pancreatitis of three levels of severity was induced in Sprague-Dawley rats with intravenous cerulein hyperstimulation plus time- and pressure-controlled intraductal infusion of saline or glycodeoxycholic acid. At 7 hours, control and pancreatitis animals received intravenous ionic CM, nonionic CM, or saline. The principal outcome measures were 24-hour survival, trypsinogen activation peptides (TAP) in ascites, and histological acinar necrosis score., Results: There was no measurable effect of CM on the index features in control animals or animals with mild or moderate AP. In severe AP, CM caused a significant increase in mortality, ascites TAP, and necrosis score., Conclusions: Intravenous CM increases pancreatic injury when administered early in the course of severe experimental AP. Because CM may convert borderline ischemia to irreversible necrosis, CECT performed early in pancreatitis to show poor perfusion and predict areas of necrosis may depict a self-fulfilling prophecy. Early CECT should be reconsidered and perhaps avoided.

Objective: This phase-I study transferred the concept of isovolemic hemodilution, which has been proven beneficial in the treatment of experimental acute pancreatitis to the patient., Summary Background Data: Pancreatic ischemia represents one main mechanism in the pathogenesis of necrotizing pancreatitis. Isovolemic hemodilution with dextran 60 has been shown experimentally to limit the progression of pancreatic necrosis by improving pancreatic microcirculation., Methods: Thirteen patients with clinically severe nonbiliary pancreatitis and CT-classification E according to Balthazar were enrolled. Exclusion criteria were anemia, coronary heart disease, chronic obstructive pulmonary disease, coagulopathies, and secondary referral. The volume of blood to be exchanged for dextran 60 was calculated from a nomogram based on body surface. Isovolemic hemodilution aimed at a hematocrit of 30%. Independent from the exchange procedure conventional fluid resuscitation was performed to adjust the central venous pressure at 6 +/- 2 mm Hg., Results: Whole blood (750-1,700 mL) was exchanged for dextran 60 during 45 to 70 minutes. No adverse effect was encountered; central hemodynamics were not affected. Considering a mean Ranson score of 5, mortality was low (7.7%). Progression of pancreatic necrosis was registered in only two patients subsequently undergoing surgical treatment (15%)., Conclusions: Isovolemic hemodilution is practicable in patients. A randomized trial has to prove whether isovolemic hemodilution can substantially alter the course of acute pancreatitis as anticipated from animal studies.