Experimental studies on pancreatic duct occlusion with prolamine

The effect of the occlusion of the pancreatic duct system with prolamine (Ethibloc) has been studied in animal experiments with dogs and mini-pigs. The solution becomes solid in the duct system and becomes disintegrated again within 11 days. This time, however, is sufficient to keep a high-grade atrophy of the exocrine parenchyma. With this method one doesn't risk the provocation of an acute pancreatitis. The endocrine function of the atrophied glands is satisfactory, no animal became diabetic. The basal jugular vein insulin shows no difference to that of the control group, but nevertheless the mean whole pancreas hormone content is reduced for insulin and somatostatin, but not for glucagon.     

Pancreatic duct occlusion with Ethibloc. An experimental study in juvenile pigs

In the transplantation of vascularized pancreatic grafts severe problems are related to the exocclusion is an improved alternative to duct ligation in producing atrophy of the exocrine pancreas while leaving the endocrine pancreas intact. Fractional growth rate in duct-ligated and duct-occluded animals was reduced to 1/3 - 1/4 of that of sham operated controls. Fasting blood glucose, fasting insulin, sum of blood glucose and glucose elimination rate during an intravenous glucose tolerance test remained normal in the duct-ligated and Ethibloc-occluded animals. There was a diminished insulin response to a maximal glucose load. In spite of this, the glucose tolerance remained virtually normal. The volume of the pancreas was reduced to 1/3 of its normal size after both experimental procedures. Histologically, the islets appeared to remain normal, while the exocrine portion of the gland was replaced by fibrous tissue. No traces of the active compound, Ethibloc, remained after 4 weeks. This study shows that pancreatic duct occlusion with Ethibloc results in impairment of endocrine function. Consequently, Ethibloc duct occlusion does not seem to be a superior alternative to other methods of producing exocrine atrophy in organs intended for transplantation.     

小型猪慢性胰腺炎模型的建立

目的建立小型猪慢性胰腺炎（CP）模型。方法西双版纳小型猪28头,随机分两组,6头为正常对照．22头经剖腹行胰管不全结扎。术后2～12周处死取出胰腺,同时取出正常组胰腺行组织学检查,进行病理分期,观察分期与喂养周数间关系。结果胰管结扎的22头小猪存活18头,15头胰腺体尾部形成CP,成功率68．2％。CP严重程度随胰管结扎后喂养周数增加而增加（r=0．39,P〈0．05）。结论小型猪胰管部分结扎能形成CP．其严重程度与胰管结扎后喂养周数间呈部分相关关系。     

Characteristics of endocrine disorders in the early stages of the development of chronic experimental pancreatitis

The experiments on normal mongrel dogs and those with chronic experimental pancreatitis were performed to reveal the early changes of the endocrine pancreas function. The concentration of immunoreactive insulin and glucagon were studied in afferent vessels of the organ after intraarterial glucose-loading during pancreatic perfusion in situ. The data obtained have shown that in chronic pancreatitis the maximum secretion of insulin is decreased and delayed, as compared to normal animals. At the same time insulin-glucagon secretion ratio remains unchanged. That was indicative of the normal alpha-cell function at the early stages of the disease.     

The duct-ligated pancreas transplant and its effect on the islet cellular composition of the host pancreas

Summary Rats rendered diabetic by streptozotocin were subjected to pancreas transplantation. After twenty weeks, the duct-ligated pancreas transplant was studied morphometrically to determine the effect of duct occlusion on the various cell populations of the islets. Concomitantly, the streptozotocin-treated host pancreas was examined for a possible influence of the graft on the diabetic pattern of islet cell population. Twenty weeks after pancreas transplantation, the volume fractions of insulin, glucagon, somatostatin and pancreatic polypeptide cells in the graft islets did not differ from those of the normal control pancreas. In the pancreas of nontransplanted diabetic rats, insulin-positive B cells were reduced from 60–65% to less than 10% of the islet volume, whereas non-B cells were significantly increased in volume density. The changes in fractional volume of the various islet cells correlated fairly well with changes in plasma concentration of the corresponding pancreas hormones. In the recipient's own pancreas, the relative volumes of glucagon and somatostatin cells were unaffected by the pancreas transplant. However, the insulin cell mass was significantly increased, and comprised about 20% of the islet volume, while cells containing pancreatic polypeptide were found only sporadically.Supported by Nordic Insulin Fund, The Swedish Diabetes Association, and MFR, proj. no. 4499. The technical assistance by M. Maxe and M. Carlesson is gratefully acknowledged     

Brief occlusion of the main pancreatic duct rapidly initiates signals which lead to increased duct cell proliferation in the rat

In the course of investigating the signals associated with pancreas regeneration, we have developed a method to initiate pancreatic duct cell proliferation by brief occlusion of the main pancreatic duct. The resulting duct cell proliferation, induced by temporary partial main duct occlusion, was compared to that induced by firmly tying a cellophane strip around the head of the pancreas for longer periods of time. Both methods stimulated a biphasic increase in duct cell proliferation, with proliferation maxima at 3 and 14 days post operation. The short duration of temporary main duct occlusion (60 s) that was needed to stimulate duct cell proliferation, and the similar duct cell proliferation profiles that were observed after both the temporary and the longer term main duct occlusion, led us to conclude that the signals which initiate proliferation occur rapidly at the beginning of each procedure.     

TRANSECTION OF THE PANCREAS BY BLUNT TRAUMA

If a diagnosis of traumatic pancreatitis is made and the patient does not improve clinically during the first 24 hours, transection of the pancreas should be suspected. If this is found to be the case at operation, the distal pancreas should be resected and the proximal end of the pancreas closed carefully with interrupted mattress suture of non-absorbable suture material. Particularly, the pancreatic duct should be ligated to prevent the formation of an external fistula. Any attempt at reapproximation of the transected pancreas will invariably result in an external pancreatic fistula if the patient survives the immediate postoperative period.     

Recovery of exocrine pancreas six months following pancreatitis induction with L-arginine in streptozotocin-diabetic rats.

The aim of the present work was to investigate the laboratory and morphologic alterations in the pancreas 6 months after pancreatitis induction with L-arginine (Arg) in normal and streptozotocin (STZ)-diabetic rats. The amylase content of the pancreas was significantly decreased in the Arg-treated groups vs. the control group. No significant changes were observed in the DNA, soluble protein and lipase contents of the pancreas. In the STZ-treated groups, the serum glucose level was significantly elevated, whereas the serum immunoreactive insulin (IRI) level was significantly decreased vs. the control group. In these treated groups, the amylase content of the pancreas was also significantly decreased, but that of trypsinogen was significantly elevated vs. the control group. Histologic sections revealed periductal fibroses, adipose tissue and tubular complexes in the Arg-treated rats, but centroacinar hyperplasia was not observed in these groups. No alterations were observed on histological examination in the diabetic rats vs. normal rats 6 months following pancreatitis induction. In conclusion, a major restitution of the pancreatic enzyme content, but moderate histologic alterations were detected 6 months following pancreatitis induction with Arg. The diabetic state appeared to shift the normal pancreatic enzyme content (decreased amylase and increased trypsinogen) in this long-term study, but not to modify the recovery of the exocrine pancreas 6 months following Arg-induced pancreatitis.     

Proteomics portrait of archival lesions of chronic pancreatitis

Chronic pancreatitis is a chronic inflammatory disorder of the pancreas. The etiology is multi-fold, but all lead to progressive scarring and loss of pancreatic function. Early diagnosis is difficult; and the understanding of the molecular events that underlie this progressive disease is limited. In this study, we investigated differential proteins associated with mild and severe chronic pancreatitis in comparison with normal pancreas and pancreatic cancer. Paraffin-embedded formalin-fixed tissues from five well-characterized specimens each of normal pancreas (NL), mild chronic pancreatitis (MCP), severe chronic pancreatitis (SCP) and pancreatic ductal adenocarcinoma (PDAC) were subjected to proteomic analysis using a "label-free" comparative approach. Our results show that the numbers of differential proteins increase substantially with the disease severity, from mild to severe chronic pancreatitis, while the number of dysregulated proteins is highest in pancreatic adenocarcinoma. Important functional groups and biological processes associated with chronic pancreatitis and cancer include acinar cell secretory proteins, pancreatic fibrosis/stellate cell activation, glycoproteins, and inflammatory proteins. Three differential proteins were selected for verification by immunohistochemistry, including collagen 14A1, lumican and versican. Further canonical pathway analysis revealed that acute phase response signal, prothrombin activation pathway, and pancreatic fibrosis/pancreatic stellate cell activation pathway were the most significant pathways involved in chronic pancreatitis, while pathways relating to metabolism were the most significant pathways in pancreatic adenocarcinoma. Our study reveals a group of differentially expressed proteins and the related pathways that may shed light on the pathogenesis of chronic pancreatitis and the common molecular events associated with chronic pancreatitis and pancreatic adenocarcinoma.     

Morphological changes in the rat exocrine pancreas after pancreatic duct ligation

In the present study, morphological changes of the exocrine pancreas in rats after pancreatic duct ligation were examined with light microscopy (hematoxylin-eosin, TUNEL, and PCNA staining) and scanning electron microscopy in order to elucidate the effects of increased pancreatic duct pressure. On the fifth day after pancreatic duct ligation, ductular proliferation, periductal fibrosis, and disappearance of acini were observed. TUNEL and PCNA staining demonstrated many apoptotic acinar cells and proliferating ductal cells immediately after ligation, which reached a maximal number on the 2nd or 3rd day. Tortuous or helical interlobular pancreatic ducts with inner surfaces containing many crater-like depressions and long cilia were found after ligation. These changes were almost identical to those observed in the pancreatic tissue of model chronic pancreatitis rats, WBN/Kob rats, and stroke-prone spontaneously hypertensive (SHRSP) rats. In summary, the morphological changes observed after pancreatic duct ligation were similar to those of chronic pancreatitis, therefore, the characteristic changes of pancreatic ducts observed in chronic pancreatitis may be caused by increased pancreatic duct pressure.     

Alcohol and Acute Pancreatitis

Alcohol abuse is associated with the development of both acute and chronic pancreatitis. The majority of patients who abuse alcohol will not develop pancreatitis; the reasons for different susceptibilities to alcohol are unknown. Most patients who present with acute alcoholic pancreatitits will have underlying chronic disease, but up to a third will have no evidence of chronic pancreatitis. Alcohol has a number of acute effects on the pancreas that are potentially toxic. These include increasing pancreatic duct pressure, decreasing pancreatic blood flow, generating free radicals, and stimulating pathologic zymogen activation within the pancreatic acinar cell.     

Impaired differentiation of endocrine and exocrine cells of the pancreas in transgenic mouse expressing the truncated type II activin receptor

Activin A is expressed in endocrine precursor cells of the fetal pancreatic anlage. To determine the physiological significance of activins in the pancreas, a transgenic mouse line expressing the truncated type II activin receptor under the control of beta-actin promoter was developed. Histological analyses of the pancreas revealed that the pancreatic islets of the transgenic mouse were small in size and were located mainly along the pancreatic ducts. Immunoreactive insulin was detected in islets, some acinar cells, and in some epithelial cells in the duct. In addition, there were abnormal endocrine cells outside the islets. The shape and the size of the endocrine cells varied and some of them were larger than islets. These cells expressed immunoreactive insulin and glucagon. In the exocrine portion, there were morphologically abnormal exocrine cells, which did not form a typical acinar structure. The cells lacked spatial polarity characteristics of acinar cells but expressed immunoreactive amylase, which was distributed diffusely in the cytoplasm. Plasma glucose concentration was normal in the transgenic mouse before and after the administration of glucose. The insulin content of the pancreas in transgenic and normal mice was nearly identical. These results suggest that activins or related ligands regulate the differentiation of the pancreatic endocrine and exocrine cells.     

Combined use of brushing cytology and endoscopic retrograde pancreatography for the early detection of pancreatic cancer

Seventy-two cases of pancreatic cancer were examined by brushing cytology combined with endoscopic retrograde pancreatography. The results of this combined method were better than those reported for the exfoliative cytologic study of pancreatic fluid. The method detected a minute cancer of the main pancreatic duct that was not detected with any other method. The cells obtained by this technique had very well-preserved cytoplasm and nuclear chromatin, which facilitated making a correct diagnosis. Though this method can be applied only to the main pancreatic duct, it is effective for the diagnosis of ductal cell carcinoma, especially those located at the head of the pancreas, which is the most common site for pancreatic cancer. It is a safe procedure, with no complications seen in this series. The differentiation of carcinoma cells from the benign atypical cells of chronic pancreatitis is illustrated and emphasized.     

Effect of somatostatin on bile-induced acute hemorrhagic pancreatitis in the dog.

In 21 female Beagle dogs an experimental pancreatitis was induced by injection of bile into the pancreatic duct system. Beside controls, dogs received 62.5 micrograms/h cyclic somatostatin (SRIF) a continuous i.v. infusion starting with a bolus of 250 micrograms 15 minutes before or 2 hours after bile injection. Following blood parameters were determined: lipase, amylase, blood count, minerals, glucose, insulin, gastrin, secretin and CCK. Two controls died within 24 hours, the others were sacrificed after 48 hours. All pancreata were examined morephologically. The controls developed all clinical signs of acute hemorrhagic pancreatitis, whereas all SRIF-treated dogs were in much better general condition. Lipase and amylase increased in all groups. In the controls insulin, gastrin and secretin remained unchanged and CCK rose slightly. SRIF-treatment diminished insulin, CCK and the test meal-induced increase of secretin. At autopsy the pancreata of the controls were nearly entirely apoplectic. The SRIF-treated dogs showed less damage of the pancreas and no severe hemorrhagic necrosis was noted. The beneficial effect of SRIF cannot only be due to an interaction with intestinal hormones. An additional direct protective effect on the exocrine parenchyma is proposed to exist.     

Pancreatic duct occlusion in the rat: report and assessment of a new technique

Temporary reduction of the exocrine pancreatic secretion may be desirable in various experimental models. In the rat this can be achieved by obstructing the connection between the pancreas and the duodenum. A new, simple technique of pancreatic duct occlusion using metal hemostatic clips is described. The reduction of secretion produced by the procedure was assessed by measuring duodenal protein, amylase, and trypsin during stimulation with cholecystokinin. Stimulated duodenal amylase activity 1 and 4 weeks following duct occlusion was reduced by approximately 80% compared with sham-operated controls, whereas proteolytic activity was reduced by 96 and 60%, respectively. The magnitude and duration of pancreatic insufficiency achieved by this technique is equivalent to that achieved with more complicated methods.     

Diabetes mellitus and the exocrine pancreas

Diabetes and carbohydrate intolerance can occur in pancreatitis. Although one-half of patients with acute pancreatitis will have some evidence of glucose intolerance during their acute illness, few will require insulin administration on either a short- or long-term basis. The diabetes seen in acute pancreatitis is likely due to a combination of factors, including alerted insulin secretion, increased glucagon release, and decreased glucose utilization by the liver and peripheral tissue. Chronic pancreatitis is often associated with diabetes mellitus, with the incidence as high as 70 percent when pancreatic calcification is present. These patients tend to be very sensitive to the effects of insulin and hypoglycemia. This is probably secondary to concurrent hepatic disease, malnutrition, and a relative decrease in glucagon reserves. The diabetes seen in chronic pancreatitis is associated with decreased insulin production. Finally, although the endocrine pancreas may influence the exocrine gland through a portal system, primary diabetes mellitus probably does not result in clinically significant alterations in pancreatic exocrine function.     

Absence of the major zymogen granule membrane protein, GP2, does not affect pancreatic morphology or secretion

The majority of digestive enzymes in humans are produced in the pancreas where they are stored in zymogen granules before secretion into the intestine. GP2 is the major membrane protein present in zymogen granules of the exocrine pancreas. Numerous studies have shown that GP2 binds digestive enzymes such as amylase, thereby supporting a role in protein sorting to the zymogen granule. Other studies have suggested that GP2 is important in the formation of zymogen granules. A knock-out mouse was generated for GP2 to study the impact of the protein on pancreatic function. GP2-deficient mice displayed no gross signs of nutrient malab-sorption such as weight loss, growth retardation, or diarrhea. Zymogen granules in the GP2 knock-out mice appeared normal on electron microscopy and contained the normal complement of proteins excluding GP2. Primary cultures of pancreatic acini appropriately responded to secretagogue stimulation with the secretion of digestive enzymes. The course of experimentally induced pancreatitis was also examined in the knock-out mice because proteins known to associate with GP2 have been found to possess a protective role. When GP2 knock-out mice were subjected to two different models of pancreatitis, no major differences were detected. In conclusion, GP2 is not essential for pancreatic exocrine secretion or zymogen granule formation. It is unlikely that GP2 serves a major intracellular role within the pancreatic acinar cell and may be functionally active after it is secreted from the pancreas.     

Survivin和MMP14在胰腺癌中的表达及临床病理意义

目的:研究胰腺癌组织中Survivin和MMP14的表达及其临床病理意义,为筛选胰腺癌分子诊断新靶标提供理论依据。方法:采用免疫组织化学技术(S-P)法检测44例胰腺癌、13例胰腺炎及21例正常胰腺组织中Survivin和MMP14表达情况,并分析其与胰腺癌临床病理参数的相关性。结果:胰腺癌组织中Survivin和MMP14蛋白均呈明显高表达,其表达与胰腺癌患者的性别、年龄、肿瘤部位、临床分期、分级及有无淋巴结转移均显著相关性(P0.05)。胰腺炎与正常胰腺组织中Survivin和MMP14蛋白表达的差异无统计学意义(P0.05),但均显著低于胰腺癌组织(P=0.000/P=0.001)。结论:Survivin和MMP14蛋白在胰腺癌组织中均呈异常高表达,但与胰腺癌的临床病理特点均无关,可能成为新的胰腺癌诊断标志物。     

Pancreatic Duct Patterns in Acute Pancreatitis: A MRI Study

Objectives

To study the MRI findings of the pancreatic duct in patients with acute pancreatitis.

Materials and Methods

A total of 239 patients with acute pancreatitis and 125 controls were analyzed in this study. The severity of acute pancreatitis was graded using the MR severity index (MRSI) and the Acute Physiology And Chronic Healthy Evaluation II(APACHE II) scoring systems. The number of main pancreatic duct (MPD) segments visualized, and both MPD diameter and pancreatic duct disruption were noted and compared with the severity of acute pancreatitis.

Results

The frequency of MPD segment visualization in the control group was higher than that in the acute pancreatitis group (p<0.05). The number of MPD segments visualized was negatively correlated with the MRSI score (p<0.05) and the APACHE II score (p<0.05). There was no difference in the MPD diameter between the acute pancreatitis and control groups or among the patients with different severities of acute pancreatitis (p>0.05). The prevalence of pancreatic duct disruption was 7.9% in the acute pancreatitis group. The prevalences of pancreatic duct disruption were 4.8% and 15.3% in the mild and severe acute pancreatitis groups based on the APACHE II score, respectively, and were 0%, 5.7% and 43.5% in the mild, moderate and severe acute pancreatitis groups according the MRSI score, respectively. The prevalence of pancreatic duct disruption was correlated with the severity of acute pancreatitis based on the APACHE II score (p<0.05) and MRSI score (p<0.05).

Conclusion

The pancreatic duct in acute pancreatitis patients was of normal diameter. The number of MPD segments visualized and visible pancreatic duct disruption on MRI may be supplementary indicators for determining the severity of acute pancreatitis.     

The distribution and localization of the monoclonal antibody-defined antigen 19-9 (CA19-9) in chronic pancreatitis and pancreatic carcinoma. An immunohistochemical study

The carbohydrate antigen 19-9 (CA19-9) is considered to be of great importance in the diagnosis, differential diagnosis and follow-up of human pancreatic carcinoma. CA19-9 antigen has been isolated and characterized as the oligosaccharide sialylazed lacto-N-fucopentaose II and a monoclonal antibody against CA19-9 is commercially available. In this immunochemical study we have examined the localisation and distribution of monoclonal anti-CA19-9 in pancreatic tissue obtained from 20 patients with a normal pancreas (lacking pancreatic tumour or evidence of inflammation), from 50 patients with chronic pancreatitis and from 50 patients with pancreatic carcinomas of various types. In the normal pancreas (free from tumour or inflammation) we found anti-CA19-9 to be localized in the branches of the pancreatic ducts with discontinuities predominantly at the apical surfaces of the lining epithelium. In chronic pancreatitis a continuous positive reaction was found in the small, medium and large ramifications of the pancreatic ducts. In ductal epithelium exhibiting mucoid transformation, a mosaic-like, discontinuous positive reaction was found, whereas in epithelium showing pseudopapillary and papillary hyperplasia a uniform positive reaction was obtained. Multilayered epithelium ("squamous metaplasia") was negative. The fluid content of any cysts present and the tubular accumulations found in chronic pancreatitis showed a positive reaction. The reaction in chronic pancreatitis differed from that in normal pancreas in its distribution but not in its intensity. All carcinomas of the exocrine pancreas showed intensely positive reaction in a very varied distribution whereas the anaplastic carcinomas gave a negative reaction. Whilst in chronic pancreatitis the binding of anti-CA19-9 was unimpressive and strictly localized, in exocrine pancreatic carcinomas binding was and strictly localized, in exocrine pancreatic carcinomas binding was very marked and diffuse in distribution. From this we conclude that malignant cells display a greater number of CA19-9 epitopes than cells in chronic pancreatitis. The difference can only be regarded as quantitative, since the immunohistochemical reaction does not allow qualitative discrimination between chronic pancreatitis and pancreatic carcinoma; CA19-9 should not be therefore termed a "tumour marker". The glycoprotein nature of CA19-9 was confirmed by sialidase and chemical desialylation.