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C Fernández-del Castillo

Publications and source records attributed to C Fernández-del Castillo.

At least 19 recordsLinked to original sources
PubMed2005

Degradation and inactivation of plasma tumor necrosis factor-alpha by pancreatic proteases in experimental acute pancreatitis.

BACKGROUND: Release of TNFalpha is thought to play an important role in mediating systemic effects in acute pancreatitis (AP). We have been unable to find an elevation of plasma TNFalpha in AP and hypothesize that it is susceptible to catabolism by circulating pancreatic proteases. METHODS: (1) AP was induced in Sprague-Dawley rats by cerulein hyperstimulation preceded by intraductal infusion of saline (mild) or glycodeoxycholic acid (severe). Healthy and sham-operated animals served as controls. Severity of pancreatitis was confirmed by histology. Plasma TNFalpha levels were measured at various time points after induction of AP with competitive ELISA. (2) Recombinant rat TNFalpha (rrTNFalpha) was incubated with trypsin, elastase, chymotrypsin and pepsin. Western Blot was performed to visualize TNF degradation. (3) RrTNFalpha was incubated in a concentration and time-dependant manner with proteases and TNF bioactivity was evaluated with a cytotoxicity assay. RESULTS: (1) Plasma TNFalpha levels in severe pancreatitis were significantly lower than in sham-operated controls after 0.5 and 6 h. (2) Incubation with proteases showed degradation in the presence of trypsin, elastase and chymotrypsin and no effect of pepsin. (3) There was a concentration dependent inactivation of rrTNFalpha in the presence of pancreatic proteases and a complete time-dependent inactivation in the presence of trypsin. CONCLUSION: Plasma TNFalpha does not rise in experimental AP, and levels are significantly lower in severe pancreatitis compared to sham-operated controls. Our study demonstrates degradation and inactivation of TNFalpha by pancreatic proteases, suggesting that it is unlikely it plays an important role in the development of distant organ failure.

Acute Disease↗
PubMed2001

Telomerase activity in periampullary tumors correlates with aggressive malignancy.

OBJECTIVE: To determine the presence of telomerase activity in a variety of periampullary malignancies and pancreatic diseases and quantify its activity to establish any association with the stage or aggressiveness of malignancy. SUMMARY BACKGROUND DATA: Progressive shortening of telomeres, repetitive DNA sequences at the ends of chromosomes, plays a role in cell senescence. Telomerase catalyzes conservation of telomeric repeats and may promote cell immortality and hence malignancy. It is absent in normal tissues but upregulated in more than 80% of cancers. METHODS: Fresh specimens of 62 periampullary tumors were snap-frozen in liquid nitrogen and adjacent tissue was formalin-fixed for histopathology. The telomerase repeat amplification protocol (TRAP) was used to obtain telomerase DNA products. These were separated with gel electrophoresis, stained with SYBR green, and quantified by densitometry. Findings were confirmed with a fluorometric TRAP assay in which fluorescent primers specific for telomerase were selectively amplified in its presence. RESULTS: Telomerase activity was upregulated in 26 of 33 periampullary malignancies (79%): 17 of 21 pancreatic adenocarcinomas (81%), 2 of 2 cholangiocarcinomas, 2 of 2 duodenal carcinomas, and 5 of 8 ampullary carcinomas (63%). Poorly differentiated periampullary tumors had significantly higher telomerase activity than well-differentiated tumors, and tumors larger than 2 cm had significantly higher telomerase activity than those 2 cm or smaller. Pancreatic ductal adenocarcinomas with lymph node metastases had significantly greater activity than node-negative cancers. Two of 11 intraductal papillary mucinous tumors were positive for telomerase activity, but only in foci of invasive carcinoma. Chronic pancreatitis (n = 7), serous cystadenomas (n = 5), benign mucinous cystic neoplasms (n = 4), neuroendocrine cancer (n = 1), and acinar cell carcinoma (n = 1) had no detectable telomerase activity. CONCLUSION: Telomerase activity is common in periampullary carcinomas. The magnitude of activity correlates with aggressiveness in pancreatic adenocarcinoma and may prove useful as a molecular index for biologic staging.

Adenocarcinoma↗
PubMed2001

Evaluation of morphology and microcirculation of the pancreas by ex vivo and in vivo reflectance confocal microscopy.

BACKGROUND: Near-infrared reflectance confocal microscopy (CM) provides non-invasive real-time images of thin virtual horizontal tissue sections with high resolution and contrast. AIM: Aim of the study was to characterize morphology, microcirculation and leukocyte-endothelial interaction (LEI) in normal pancreas by in vivo and ex vivo CM. METHODS: For CM we used water immersion objective lenses of high numerical aperture and near-infrared wavelengths. Experimentally measured lateral optical resolution is 0.5-1 micron and the axial resolution is 3-5 microns. The maximum depth of resolution was 300-400 microns. For ex vivo imaging, freshly excised pancreatic tissue from rats was studied by reflectance CM and conventional histopathology. For in vivo CM, the pancreatic head was exteriorized on a specially constructed stage for imaging the microcirculation and LEI. Images were obtained in real time at rates of 30 frames/s and later analyzed off-line to evaluate LEI and functional capillary density (FCD). RESULTS: CM allowed high resolution visualization of normal pancreas acinar cells, ducts, islets, capillaries and LEI in postcapillary venules. Histological images and optical sections from ex vivo CM can be correlated. Cellular morphology is better analyzed by conventional histology, but angioarchitecture and connective tissue structure are better evaluated by CM. FCD (265.7 +/- 16.6 cm-1) and LEI (rolling leukocytes 5.3 +/- 1.6/100 microns/sticking leukocytes 1.5 +/- 0.9/100 microns) were evaluated by in vivo CM in the normal pancreas. CONCLUSIONS: CM findings in tissues ex vivo correlate with those of classical histology but add informative details of connective tissue structure and angioarchitecture. Potential future applications for in vivo CM include real-time analysis of microcirculation, leukocyte-endothelial interaction and angiostructure in inflammatory and malignant pancreatic diseases.

Animals↗
PubMed2001

Cystic neoplasms of the pancreas.

Cystic tumors of the pancreas have become increasingly prevalent. In large series, more than 90% of pancreatic cystic neoplasms are accounted for by mucinous cystadenomas and cystadenocarcinomas, serous cystadenomas, and intraductal papillary mucinous tumors. Differentiating cystic neoplasms from pseudocysts can almost always be accomplished by clinical and radiological means, but in doubtful cases, when observation is contemplated, or when it is important to determine preoperatively the type of cystic neoplasm, cyst fluid analysis is useful. This can be readily obtained by endoscopic ultrasound, and analysis of enzymes, viscosity, cytology and a variety of tumor markers allows for a better differential diagnosis.

Cystadenoma, Mucinous↗
PubMed1999

Interstitial trypsinogen release and its relevance to the transformation of mild into necrotizing pancreatitis in rats.

BACKGROUND & AIMS: Intracellular activation of trypsinogen is currently believed to initiate pancreatitis. Factors responsible for the progression of mild to necrotizing pancreatitis are poorly understood. This study evaluated the significance of interstitial protease release and activation in this process. METHODS: In rats with cerulein-induced pancreatitis, concentrations of trypsinogen and its activation peptide TAP were measured in lymph and blood, and pancreatic injury was determined. Activation of extracellular trypsinogen was induced by intravenous infusion of enterokinase, which does not enter the acinar cell. Gabexate mesilate (acinar cell permeable) or soybean trypsin inhibitor (acinar cell nonpermeable) was administered to distinguish the effects of intracellular or extracellular protease activation. RESULTS: In cerulein pancreatitis, trypsinogen levels increased prominently and were highest in lymph and portal vein blood, whereas TAP increments were modest. Combined cerulein/enterokinase infusions resulted in marked TAP increases in lymph and blood and in severe necrohemorrhagic pancreatitis. Gabexate mesilate as well as soybean trypsin inhibitor significantly decreased TAP levels in both lymph and blood and reduced pancreatic injury, with no significant differences between groups. CONCLUSIONS: In secretagogue-induced pancreatitis, large amounts of trypsinogen are present in the interstitium and drain via the portal and lymphatic circulation. Activation of this extracellular trypsinogen induces hemorrhagic necrosis in a setting of mild edematous pancreatitis. This phenomenon may be the central event in the progression to fulminant necrotizing pancreatitis.

Animals↗
PubMed1999

Specific therapy for local and systemic complications of acute pancreatitis with monoclonal antibodies against ICAM-1.

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.

Acute Disease↗
PubMed1999

Sequential accumulation of K-ras mutations and p53 overexpression in the progression of pancreatic mucinous cystic neoplasms to malignancy.

OBJECTIVE: Pancreatic mucinous cystic neoplasms (MCNs) provide a spectrum of neoplastic changes ranging from benign to malignant. The authors have correlated K-ras mutations and p53 overexpression with the evolution of these tumors. METHODS: Areas of mild, moderate, or severe dysplasia were microdissected from paraffin-embedded tissue sections of 28 different MCNs (10 benign, 9 borderline, 9 malignant). Nonneoplastic pancreatic ducts were also microdissected from tissues adjacent to the tumors. Ten serous cystadenomas served as negative controls. K-ras codon 12 mutations were identified by a mutant-enriched nested polymerase chain reaction-restriction fragment length polymorphism assay and confirmed by sequencing. p53 overexpression was demonstrated by immunohistochemistry. RESULTS: K-ras mutations were detected in 20% of benign, 33% of borderline, and 89% of malignant MCNs. Histologically, mutations were found in 26% (7/27) of MCN epithelia with mild dysplasia, 38% (5/13) of MCN epithelia with moderate dysplasia, and 89% (8/9) of MCN epithelia with severe dysplasia or carcinoma. Ten percent (4/39) of nonneoplastic pancreatic ducts at the margins of MCN harbored mutations, all associated with borderline or malignant tumors. Overexpression of p53 occurred in none of the benign or borderline MCNs but in 44% (4/9) of the malignant tumors (p = 0.006 benign/borderline vs. malignant). p53 immunoreactivity was concentrated in areas of severe dysplasia/carcinoma or invasion, where K-ras mutation had been detected. CONCLUSION: These findings demonstrate a sequential accumulation of genetic changes in the carcinogenesis of MCN. K-ras mutations appear early and increase in proportion with increasing dysplasia. Overexpression of p53 is a late finding observed only in carcinomas, and in combination with mutated K-ras genes. The presence of K-ras mutations in nonneoplastic ducts supports formal pancreatic resection over enucleation for treatment. Mucinous cystic neoplasms may be a useful model to study the evolution of pancreatic ductal adenocarcinomas, in which precursor lesions remain unknown.

DNA Mutational Analysis↗
PubMed1999

Trypsin and activation of circulating trypsinogen contribute to pancreatitis-associated lung injury.

Pancreatic proteases are secreted in acute pancreatitis, but their contribution to associated lung injury is unclear. Applying models of mild edematous (intravenous caerulein) and severe necrotizing (intraductal glycodeoxycholic acid) pancreatitis in rats, we showed that both trypsinogen and trypsin concentrations in peripheral blood, as well as lung injury, correlate with the severity of the disease. To isolate the potential contribution of proteases to lung injury, trypsin or trypsinogen was injected into healthy rats or trypsinogen secreted in caerulein pancreatitis was activated by intravenous enterokinase. Pulmonary injury induced by protease infusions was dose dependent and was ameliorated by neutrophil depletion. Trypsinogen activation worsened lung injury in mild pancreatitis. In vitro incubation of leukocytes with trypsinogen showed that stimulated leukocytes can convert trypsinogen to trypsin. In conclusion, this study demonstrates that the occurrence and severity of pancreatitis-associated lung injury (PALI) corresponds to the levels of circulating trypsinogen and its activation to trypsin. Neutrophils are involved in both protease activation and development of pulmonary injury.

Acute Disease↗
PubMed1998

Middle segment pancreatectomy: a novel technique for conserving pancreatic tissue.

Pancreatoduodenectomy and extended distal pancreatectomy for benign tumors in the pancreatic neck and body incur a notable waste of normal tissue and unnecessary risk of both diabetes mellitus and splenic loss. We describe the technique of a limited resection of the middle portion of the pancreas, termed middle segment pancreatectomy, and report our results in 12 patients. Middle segment pancreatectomy was used in 12 consecutive patients with pancreatic tumors of the neck or body. The transected pancreatic head was sutured with duct ligation, and a Roux-en-Y loop of jejunum was anastomosed to the tail using mucosa-to-mucosa duct approximation and a 5F catheter for duct stenting and drainage. In 12 patients, 7 with cystic tumors (5 patients with serous cystadenoma; 2 patients with mucinous cystic neoplasms), 3 with islet cell adenomas, 1 with islet cell carcinoma, and 1 with intraductal papillary mucinous tumor, the tumor was resected by a middle segment pancreatectomy. In each case, the tumor, measuring 0.9 to 5.2 cm, lay in the neck or body of the pancreas and could not be safely enucleated without compromising the pancreatic duct. Each tumor was resected with clear margins. Two patients had a temporary pancreatic fistula; 1 patient had delayed gastric emptying. Median postoperative length of stay was 8 days. No patient became diabetic or required oral pancreatic enzyme supplements. No local recurrences occurred after a mean follow-up of 18 months. Middle segment pancreatectomy is a safe and effective technique for resecting selected pancreatic tumors in the neck and body of the pancreas while preserving pancreatic endocrine and exocrine function and the spleen.

Humans↗
PubMed1998

Implications of peritoneal cytology for pancreatic cancer management.

OBJECTIVE: To assess the implications of positive cytology for malignant cells (positive results) from peritoneal washings in the management of patients with pancreatic cancer. DESIGN: Retrospective cohort study. SETTING: Referral practice in a university hospital. PATIENTS: A total of 32 consecutive pancreatic cancer patients with positive results from peritoneal washings during a 4-year period, 17 with visible biopsy-proven intraabdominal metastases at the time of laparoscopy or laparotomy and 15 without visible metastases. A treatment-matched control group of 30 patients was randomly selected from a group of 105 patients with negative cytology for malignant cells (negative results) from peritoneal-fluid cytology. INTERVENTIONS: Eight of 17 patients with visible metastases underwent treatment with chemotherapy, radiation, or both; 13 of the 15 patients with no visible metastases underwent further treatment, including pancreatic resection in 2 patients and external beam radiation in 13 patients (3 with intraoperative radiation therapy). MAIN OUTCOME MEASURES: Time to metastases and mortality. RESULTS: Median survival among patients with and without visible metastasis was 7.8 months and 8.6 months, respectively (P=.95), despite the fact that patients without visible metastases received more treatment. Patients without visible metastases at presentation were found to have metastatic disease as documented by computed tomographic scan or subsequent laparotomy at a median time of 2.9 months. The survival of treatment-matched patients with negative cytology was significantly longer (median, 13.5 months; P=.04). CONCLUSIONS: Pancreatic cancer patients with peritoneal micrometastases have a dismal outcome even without macroscopic metastases. Since these patients do not benefit from local therapy, the finding of a positive result from peritoneal-fluid cytologic testing contraindicates further irradiation or surgery, except for specific complications.

Cohort Studies↗
PubMed1998

Metastases to the pancreas and their surgical extirpation.

BACKGROUND: The pancreas is an unusual but occasionally favored site for metastases, notably from carcinomas of the kidney and lung. The pancreas may be the only identified locus of spread, and therefore may provide an opportunity for significant palliation or even cure using pancreatectomy. OBJECTIVE: To report the treatment and outcome of patients presenting with metastases to the pancreas. DESIGN: Five-year survey. SETTING: Tertiary referral center. PATIENTS: Ten patients with apparently isolated metastases to the pancreas were identified from January 1, 1991, to December 31, 1995. All patients were followed up until death or to September 1997. RESULTS: The patients had been treated previously for carcinoma of the lung (n=4), renal cell carcinoma (n=2), sarcoma (n=2), breast carcinoma (n=1), and endometrial carcinoma (n=1). The interval between primary treatment and presentation of the metastases averaged 70 months (14-24 months for lung cancer, 10 and 22 years for renal cell carcinoma, 4 and 6 years for sarcoma, 8 years for breast cancer, and 36 months for endometrial carcinoma). Metastases were initially misdiagnosed as primary pancreatic cancers in 7 patients. In 4 patients (those with renal cell cancer and sarcomas), the tumor was completely resected using total pancreatectomy (n=3) or Whipple resection (n=1). Survival after diagnosis averaged 22 months. Two of the 4 patients undergoing pancreatic resection remain alive and well 20 and 25 months after pancreatectomy. CONCLUSIONS: The pancreas may be the presenting and perhaps sole locus for metastasis, typically years after treatment for certain extrapancreatic malignant neoplasms. Recognition and surgical treatment can provide worthwhile palliation and long-term survival.

Female↗
PubMed1998

Débridement and closed packing for the treatment of necrotizing pancreatitis.

OBJECTIVE: To evaluate the results of débridement and closed packing for necrotizing pancreatitis and to determine the optimal timing of surgical intervention based on patient outcomes. METHODS: Between February 1990 and November 1996, 64 consecutive patients with necrotizing pancreatitis were treated with necrosectomy followed by closed packing of the cavity with stuffed Penrose and closed suction drains. The mean APACHE II score immediately before surgery was 9, and 31% of the patients had organ failure. Patients were stratified with an outcome score based on death and major complications; this was correlated with the timing of surgical intervention. The data were then subjected to cut-point analysis by sequential group comparison. RESULTS: Patients underwent surgery a median of 31 days after diagnosis. Fifty-six percent had infected necrosis. The mortality rate was 6.2% and was no different in infected or sterile necrosis. Eleven patients required a second surgical procedure and 13 required percutaneous drainage; a single surgical procedure sufficed in 69%. Enteric fistulae occurred in 16% of patients. The mean hospital stay after surgery was 41 days, and the interval until return to regular activities was 147 days. A significant negative correlation between duration of pancreatitis and outcome scores was found, and sequential group comparison demonstrated that the change point at which significantly better outcomes were encountered was day 27. CONCLUSION: Débridement of pancreatic necrosis followed by closed packing and drainage is accomplished with a low mortality rate and reduced rates of complications and second surgical procedures. Although intervention is best deferred until the demarcation of necrosis is complete, delay beyond the fourth week confers no additional advantage.

APACHE↗
PubMed1998

On the protective mechanisms of nitric oxide in acute pancreatitis.

BACKGROUND: Ectopic protease activation, microcirculatory changes, and leucocyte activation are the main events in the pathogenesis of acute pancreatitis. Nitric oxide (NO) is known to be a key mediator in the normal and inflamed pancreas. AIMS: To investigate the targets on which NO exerts its effect in caerulein induced pancreatitis. METHODS: Acute pancreatitis was induced in rats which additionally received either the NO synthase substrate, L-arginine; the NO donor, sodium nitroprusside; or the NO synthase inhibitor, N-nitro-L-arginine methyl ester (L-NAME). At six hours, pancreatic injury (oedema, leucocyte content, ectopic trypsinogen activation) was analysed and pancreatic oxygenation and perfusion were determined. A direct influence of NO on amylase secretion and trypsinogen activation was evaluated separately in vitro. RESULTS: Both NO donors reduced the grade of inflammation. L-NAME increased the severity of inflammation, while decreasing pancreatic tissue oxygenation. Although neither amylase secretion nor intracellular trypsinogen activation in caerulein stimulated pancreatic acini was influenced by either NO donors or inhibitors, both NO donors decreased intrapancreatic trypsinogen activation peptide (TAP) and pancreatic oedema in vivo, and L-NAME increased TAP. CONCLUSIONS: NO protects against injury caused by pancreatitis in the intact animal but has no discernible effect on isolated acini. It is likely that in pancreatitis NO acts indirectly via microcirculatory changes, including inhibition of leucocyte activation and preservation of capillary perfusion.

Acute Disease↗
PubMed1998

Subcellular kinetics of early trypsinogen activation in acute rodent pancreatitis.

To investigate the debated role of intracellular trypsinogen activation and its relation to lysosomal enzyme redistribution in the pathogenesis of acute pancreatitis, rats were infused with the cholecystokinin analog caerulein at 5 micrograms.kg-1.h-1 for intervals up to 3 h, and the changes were contrasted with those in animals receiving saline or 0.25 microgram.kg-1.h-1 caerulein. Saline or 0.25 microgram.kg-1.h-1 caerulein did not induce significant changes. In contrast, 5 micrograms.kg-1.h-1 caerulein caused significant hyperamylasemia and pancreatic edema within 30 min. Pancreatic content of trypsinogen activation peptide (TAP) increased continuously (significant within 15 min). TAP generation was predominantly located in the zymogen fraction during the first hour but expanded to other intracellular compartments thereafter. Cathepsin B activity in the zymogen compartment increased continuously throughout the experiments and correlated significantly with TAP generation in the same compartment. Total trypsinogen content increased to 143% with marked interstitial trypsinogen accumulation after 3 h. Supramaximal caerulein stimulation causes trypsinogen activation by 15 min that originates in the zymogen compartment and is associated with increasing cathepsin B activity in this subcellular compartment. However, a much larger pool of trypsinogen survives and accumulates in the extracellular space and may become critical in the evolution of necrotizing pancreatitis.

Acute Disease↗
PubMed1997

Pancreatic injury in rats induced by fatty acid ethyl ester, a nonoxidative metabolite of alcohol.

BACKGROUND & AIMS: The mechanism by which alcohol injures the pancreas remains unknown. Alcohol-intoxicated humans have high levels of fatty acid ethyl esters (FAEEs), nonoxidative products of ethanol metabolism, in blood, pancreas, and liver. The aims of this study were to determine whether FAEEs are toxic to the pancreas in vivo and, if so, to assess whether this injury is specific to the pancreas and to compare it to the injury observed in acute pancreatitis. METHODS: FAEEs were infused into Sprague-Dawley rats. Levels of FAEEs in plasma and pancreas were measured, and pancreatic injury was assessed during a 48-hour period for edema formation and ectopic trypsinogen activation and by light and electron microscopy. RESULTS: FAEEs induced highly significant increases in pancreatic edema, pancreatic trypsinogen activation, and vacuolization of acinar cells. These findings were specific to the pancreas and were not found in liver, lung, myocardium, skeletal muscle, or subcutaneous fat. CONCLUSIONS: FAEEs at concentrations found in human plasma produce a pancreatitis-like injury in rats, providing direct evidence that FAEEs can produce organ-specific toxicity. Thus, FAEEs may contribute to acute alcohol-induced damage to the pancreas.

Animals↗
PubMed1997

Analysis of K-ras oncogene mutations in chronic pancreatitis with ductal hyperplasia.

BACKGROUND: K-ras oncogene mutations have been identified in up to 95% of pancreatic cancers, implying their critical role in their molecular pathogenesis. However, the earliest stage in which K-ras mutations can be detected in potential precursor lesions of pancreatic cancer remains unclear. This study evaluates pancreatic ductal hyperplasia in the setting of chronic pancreatitis, which predisposes to pancreatic cancer development, for K-ras codon 12 and 13 mutations. METHODS: Paraffin-embedded surgical specimens from 42 patients with chronic pancreatitis were examined microscopically for the presence of ductal hyperplasia. Both hyperplastic and nonhyperplastic ducts were microdissected from the specimens that contained hyperplasia (11 of 42). Four of the remaining specimens without hyperplasia served as controls. Genomic DNA was extracted, and polymerase chain reaction and amplification of the K-ras oncogene was performed. Polymerase chain reaction products were evaluated by means of hybridization to mutant specific oligonucleotide probes and by means of automated DNA sequencing. RESULTS: K-ras codon 12 mutations representing glycine to valine substitutions were present in 2 of (18%) 11 patients with ductal hyperplasia. No mutations were found in the controls without ductal hyperplasia. CONCLUSIONS: Our study supports the premise that K-ras mutations develop in a subset of chronic pancreatitis associated hyperplasia and provides a genetic basis for the potential progression of chronic pancreatitis to pancreatic cancer.

Adult↗
PubMed1997

A rat model of pancreatic ductal adenocarcinoma: targeting chemical carcinogens.

BACKGROUND: Current experimental models of pancreatic cancer either fail to reproduce the ductal phenotype or cause simultaneous cancers in other organs also. To develop an animal of pancreatic cancer that accurately mimics the human condition, we restricted carcinogenic exposure to the pancreas and specifically targeted ductal epithelial cells. Three different carcinogens were either implanted directly into the pancreas or infused into the pancreatic duct, with or without near-total pancreatectomy (as a means of inducing pancreatic ductal cell proliferation). METHODS: Groups of male Sprague-Dawley rats were exposed to varying doses of dimethylbenzanthracine (DMBA), methynitronitrosoguanidine, or ethylnitronitrosoguanidine either through direct implantation into the pancreas or infusion into the pancreatic duct. Near-total pancreatectomy was added in all groups except two DMBA implantation groups. Surviving rats were killed at 3, 6, 9, or 12 months, and the pancreata were evaluated histologically. RESULTS: All three carcinogens caused pancreatic inflammation, ductal hyperplasia, atypia, and dysplasia beginning by 3 months and becoming more prominent at later time points. Only DMBA caused frequent invasive pancreatic ductal adenocarcinoma, which was first evident by 6 months. The prevalence of pancreatic cancer among DMBA-treated rats evaluated after 10 months was 39% (19 of 49). The addition of pancreatic resection did not enhance pancreatic cancer development. CONCLUSIONS: Of the strategies tested, only direct implantation of DMBA into the rat pancreas frequently produces pancreatic cancer histologically similar to human ductal adenocarcinoma. The development of hyperplastic, atypical, and dysplastic changes preceding and accompanying carcinomas suggests that these lesions are preneoplastic. This model recapitulates the progression from normal to neoplastic epithelium and is likely to be useful for the study of morphologic and molecular mechanisms underlying the early stages of pancreatic carcinogenesis and for the investigation of novel diagnostic and therapeutic techniques.

9,10-Dimethyl-1,2-benzanthracene↗