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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The role of ischaemia in the pathogenesis of acute pancreatitis is unknown. Some experimental studies have shown that ischaemia has little effect on the pancreas, while others have found an association with pancreatic injury. Ischaemia-reperfusion damage has been well documented in other sites such as the intestine, cardiac muscle, and skeletal muscle. However, in the pancreas, injury is usually seen only after complete ischaemia, which is uncommon clinically. Experimental chronic pancreatitis is characterized by low pancreatic blood flow, low interstitial pH, and impaired pancreatic tissue oxygenation, which are all findings consistent with the ischaemia-reperfusion mechanisms. Acute pancreatitis is also associated with a reduction in pancreatic blood flow and evidence of free radical generation, similarly suggesting the possibility of ischaemia-reperfusion injury. Ethanol ingestion, which is commonly associated clinically with both chronic and acute pancreatitis, may itself contribute to an ischaemic-reperfusion injury. We have shown that administration of ethanol to cats decreases pancreatic blood flow and may also directly activate neutrophils. Further investigation is needed to determine whether or not these findings are also associated with an ischaemia-reperfusion injury.
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PMID:Ischaemia-reperfusion mechanisms in acute pancreatitis. 886 66

Despite numerous experimental and clinical investigations there is no consensus on the evolution of chronic pancreatitis (CP). In the 1970s and 1980s, Sarles persistently emphasised the de novo evolution of CP due to pancreatolithiasis. In recent years, however, clinical and morphological studies have provided strong evidence for the initial proposal of acute pancreatitis progressing to chronic pancreatitis. The so-called necrosis-fibrosis-sequence theory is supported by immunohistochemical work suggesting that inflammatory mediators primarily contribute to tissue destruction and that infiltration of pancreatic nerves by immune cells is a pathogenetic factor for the generation of pain in CP. While Sarles postulates that acinar hypersecretion and an imbalance of pancreatic stone promoting and inhibiting factors trigger the evaluation of CP, the necrosis-fibrosis-sequence theory also involves other pathomechanisms (e.g. changes in ductal permeability, ischemia, oxidative stress) which have been shown to cause (acute) pancreatic injury. Despite this unifying template, which also lessens the need to identify independent mechanisms for the pathogenesis of acute and chronic alcoholic pancreatitis, there are still open questions, e.g. on genetic factors that (like in hereditary CP) may explain the different susceptibility of the pancreas to injury and the individual immunological response.
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PMID:[New aspects in the pathophysiology of chronic pancreatitis]. 941 Jun 72

Abdominal pain, excruciating and recurrent, is the dominant feature of chronic pancreatitis that initially brings most of the patients to the physician's attention. The pathogenesis of pancreatic pain is often multifactorial and explains why not all patients respond to the same mode of therapy. Increased intraductal pressure as a result of ductal stricture and/or calculi is the most frequent cause for pain in the large majority of patients with large duct disease. Interstitial hypertension, ongoing pancreatic ischemia, neuronal inflammation, and extra pancreatic complications may be the sole or additional factors in the pathogenesis of pain. The management of pain is difficult and requires a team approach. Internist, gastroenterologist, radiologist, surgeon, and a psychiatrist may have to work together to achieve maximum success. Drug and alcohol dependency needs vigorous management by a psychiatrist. Supportive therapy with a low-fat diet and antioxidant supplementation are helpful. When analgesic therapy fails, surgery may have to be considered much before a narcotic dependency develops. If at all of use, oral pancreatic enzyme therapy is suitable only in a selected group of patients--women with idiopathic pancreatitis. Endoscopic papillotomy, stent placement, and stone removal, although becoming popular, are under trial only and appear to be suitable in those with obstructive disease mostly localized to the head of the pancreas without much proximal disease. A patient with a dilated duct system is a good candidate for Puestow's pancreatico-jejunal anastamosis, which appears to be the best surgical procedure. Those with small duct diseases are difficult to be managed. Resective procedures and celiac ganglion blocking are suggested but not of much help.
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PMID:Chronic pancreatitis: pathogenesis and management of pain. 975 70

Free radicals have been implicated in over a hundred disease conditions in humans, including arthritis, hemorrhagic shock, atherosclerosis, advancing age, ischemia and reperfusion injury of many organs, Alzheimer and Parkinson's disease, gastrointestinal dysfunctions, tumor promotion and carcinogenesis, and AIDS. Antioxidants are potent scavengers of free radicals and serve as inhibitors of neoplastic processes. A large number of synthetic and natural antioxidants have been demonstrated to induce beneficial effects on human health and disease prevention. However, the structure-activity relationship, bioavailability and therapeutic efficacy of the antioxidants differ extensively. Oligomeric proanthocyanidins, naturally occurring antioxidants widely available in fruits, vegetables, nuts, seeds, flowers and bark, have been reported to possess a broad spectrum of biological, pharmacological and therapeutic activities against free radicals and oxidative stress. We have assessed the concentration- or dose-dependent free radical scavenging ability of a novel IH636 grape seed proanthocyanidin extract (GSPE) both in vitro and in vivo models, and compared the free radical scavenging ability of GSPE with vitamins C, E and beta-carotene. These experiments demonstrated that GSPE is highly bioavailable and provides significantly greater protection against free radicals and free radical-induced lipid peroxidation and DNA damage than vitamins C, E and beta-carotene. GSPE was also shown to demonstrate cytotoxicity towards human breast, lung and gastric adenocarcinoma cells, while enhancing the growth and viability of normal human gastric mucosal cells. The comparative protective effects of GSPE, vitamins C and E were examined on tobacco-induced oxidative stress and apoptotic cell death in human oral keratinocytes. Oxidative tissue damage was determined by lipid peroxidation and DNA fragmentation, while apoptotic cell death was assessed by flow cytometry. GSPE provided significantly better protection as compared to vitamins C and E, singly and in combination. GSPE also demonstrated excellent protection against acetaminophen overdose-induced liver and kidney damage by regulating bcl-X(L) gene, DNA damage and presumably by reducing oxidative stress. GSPE demonstrated excellent protection against myocardial ischemia-reperfusion injury and myocardial infarction in rats. GSPE was also shown to upregulate bcl(2) gene and downregulate the oncogene c-myc. Topical application of GSPE enhances sun protection factor in human volunteers, as well as supplementation of GSPE ameliorates chronic pancreatitis in humans. These results demonstrate that GSPE provides excellent protection against oxidative stress and free radical-mediated tissue injury.
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PMID:Free radicals and grape seed proanthocyanidin extract: importance in human health and disease prevention. 1096 38

The etiology of acute pancreatitis, apart from alcohol abuse and cholelithiasis may also include a vascular component responsible for pancreatic ischemia. It is now acknowledged that chronic pancreatitis may be a consequence of the acute variant, but it remains unclear what factors influence this sequence of morphological changes. In order to clarify this issue we proposed a model of experimental acute pancreatitis in rats induced by a 30 min reduction of blood flow in inferior splenic artery followed by reperfusion. Rats were sacrificed at 1 h, 12 h, 24 h, and 2, 3, 5, 7, 14, 21, 28 days after cessation of ischemia. We performed histopathological examination of pancreatic tissue and measured pancreatic blood flow, plasma amylase activity and interleukin-1 beta concentration. The present findings indicate that transient pancreatic ischemia leads to the development of acute necro-haemorrhagic pancreatitis. The morphological features of acute inflammation are correlated positively with functional disorders. In some cases the features of chronic pancreatitis may appear transiently after the acute phase, whereas the repair of postinflammatory injury involves the regeneration of acinar cells.
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PMID:Morphological changes and morphological-functional correlations in acute experimental ischemia/reperfusion pancreatitis in rats. 1124 88

The objective of this study was to assess the biochemical and histological signs of pancreatic damage development and pancreatic recovery in the course of ischemia-reperfusion induced pancreatitis. Acute pancreatitis was induced in rats by limitation of pancreatic blood flow (PBF) in inferior splenic artery for 30 min using microvascular clips, followed by reperfusion. Rats were sacrificed at the time: 1 h, 12 h, 24 h, and 2, 3, 5, 7, 10, 14, 21 and 28 days after ischemia. PBF was measured using laser Doppler flowmeter. Plasma amylase, interleukin 1beta (IL-1beta) and interleukin 10 (IL-10) concentration, pancreatic DNA synthesis, as well as, morphological features of pancreatic damage were examined. Ischemia with reperfusion caused acute necrotizing pancreatitis followed by pancreatic regeneration. After removal of microvascular clips, PBF was reduced and the maximal fall of PBF was observed 24 h after ischemia, then PBF grew reaching the control value at 28th day. Plasma amylase activity was increased between 12th h and 3rd day with maximum at 24 h after ischemia. Also plasma IL-1beta and IL-10 were elevated with maximal value at the first and second day after ischemia, respectively. DNA synthesis was maximally reduced at the first day (by 70%) and from second day the reversion of this tendency was observed with full restoration of pancreatic DNA synthesis within four weeks. Morphological features of pancreatic tissue showed necrosis, strongly pronounced edema and leukocyte infiltration. Maximal intensity of morphological signs of pancreatic damage was observed between first and second day of reperfusion. During pancreatic regeneration between second and tenth day after ischemia the temporary appearance of chronic pancreatitis-like features such as fibrosis, acinar cell loss, formation of tubular complexes and dilatation of ducts was observed. The regeneration was completed within four weeks after pancreatitis development. We conclude that partial and temporary pancreatic ischemia followed by reperfusion causes acute necrotizing pancreatitis with subsequent regeneration within four weeks. Pancreatic repair after necrotizing pancreatitis is connected with the increase in plasma IL-10 concentration and transitory formation of tubular complexes.
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PMID:Pancreatic damage and regeneration in the course of ischemia-reperfusion induced pancreatitis in rats. 1145 2

Pancreatic microvascular control is a complex physiological process which is incompletely understood. Blood flow in the pancreas is altered by a large number of endogenous and exogenous factors in the context of acute and chronic pancreatitis. The frequency of progression from acute pancreatitis to a chronic form is a controversial question. In acute pancreatitis reductions in blood flow and alterations of microvascular integrity resulting in impaired tissue oxygenation play an important part in the progression and possibly the initiation of the disease. Endothelin and nitric oxide are believed to be two of the most effective vasoactive mediators. The beneficial effect of therapeutic strategies affecting vasoactive mediators is confirmed in experimental studies. Chronic disease is associated with decreased pancreatic blood flow and histological changes in the vasculature in both patients and animal models. Further studies are needed to clarify whether ischemia in chronic pancreatitis is more important in perpetuating the disease or as primary cause of the inflammatory processes.
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PMID:Importance of microcirculatory disturbances in the pathogenesis of pancreatitis. 1175 96

The present paper summarizes the various themes of research which have been developed in the department of medical gastroenterology since it was created in 1977. These include: in pancreatology, the study of chronic pancreatitis pathogenesis, acute pancreatitis pathogenesis and immunomodulation, endoscopic treatment of chronic pancreatitis, the development of new imaging techniques of the bile ducts and the pancreas, as well as the treatment of pancreatic cancer and benign or malignant biliary diseases. in hepatology, the immunomodulation of liver cirrhosis, especially alcoholic liver disease, the modulation of experimental acute and chronic hepatitis, the study of liver ischemia-reperfusion. Clinical hepatology has focused on liver transplantation, prognosis factors of chronic liver disease and treatment of portal hypertension and viral hepatitis. in gut diseases, the treatment of gastro-oesophageal reflux and its complications, the therapeutic endoscopy of the upper and lower GI and the prevention, as well as the treatment, of colon cancer, the pathogenesis and the immunopharmacology of inflammatory bowel diseases and the clinical enteral and parenteral nutrition.
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PMID:[The medical gastroenterology department]. 1258 14

A duodenum-preserving pancreatic head resection (DPPHR) was first reported by Beger et al. in 1980. However, its application has been limited to chronic pancreatitis because of it is a subtotal pancreatic head resection. In 1990, we reported duodenum-preserving total pancreatic head resection (DPTPHR) in 26 cases. This opened the way for total pancreatic head resection, expanding the application of this approach to tumorigenic morbidities such as intraductal papillary mucinous tumor (IMPT), other benign tumors, and small pancreatic cancers. On the other hand, Nakao et al. reported pancreatic head resection with segmental duodenectomy (PHRSD) as an alternative pylorus-preserving pancreatoduodenectomy technique in 24 cases. Hirata et al. also reported this technique as a new pylorus-preserving pancreatoduodenostomy with increased vessel preservation. When performing DPTPHR, the surgeon should ensure adequate duodenal blood supply. Avoidance of duodenal ischemia is very important in this operation, and thus it is necessary to maintain blood flow in the posterior pancreatoduodenal artery and to preserve the mesoduodenal vessels. Postoperative pancreatic functional tests reveal that DPTPHR is superior to PPPD, including PHSRD, because the entire duodenum and duodenal integrity is very important for postoperative pancreatic function.
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PMID:[Duodenum-preserving total pancreatic head resection and pancreatic head resection with segmental duodenostomy]. 1285 95

Biliary stricture and duodenal obstruction have been increasingly recognized as complications of chronic pancreatitis. The anatomical relationship of the distal common bile duct and the duodenum with the head of the pancreas is the main factor for their involvement in chronic pancreatitis. In hospitalized patients with pancreatitis, the incidence of biliary stricture and duodenal obstruction is reported to be about 6% and 1.2%, respectively. For patients requiring an operation for chronic pancreatitis the incidence increases to 35% for biliary stricture and 12% for duodenal obstruction. Fibrosis around the distal common bile duct can cause stenosis with obstruction of bile flow. Clinically, the presentation of these patients ranges from being asymptomatic with elevated alkaline phosphatase or bilirubin, or both, to being septic with cholangitis. Jaundice, cholangitis, hyperbilirubinemia, and persistent elevation of serum alkaline phosphatase occur more frequently in patients with pancreatitis with a biliary stricture. A twofold elevation of alkaline phosphatase is a marker of possible common duct stenosis in patients with chronic pancreatitis. The incidence of both biliary cirrhosis and cholangitis in these patients is about 10%. ERCP reveals a characteristic long, smoothly tapered stricture of the intrapancreatic common bile duct. In duodenal obstruction, the factors that convert self-limiting edema to chronic fibrosis and stricture formation are unknown, but ischemia superimposed on inflammation may be the major cause. These patients present with a prolonged history of nausea and vomiting. Barium studies typically show a long constricting lesion of the duodenum, and endoscopy reveals reactive inflammatory changes in a narrowed duodenum. Operation is indicated in patients with common bile duct strictures secondary to chronic pancreatitis when there is evidence of cholangitis, biliary cirrhosis, common duct stones, progression of stricture, elevation of alkaline phophatase and/or bilirubin for over a month, and an inability to rule out cancer. The operation of choice is either choledochoduodenostomy or choledochojejunostomy. A cholecystoenterostomy is less favored because of its higher failure rate (23%). Endoscopic stenting plays a role in patients who are unfit for surgery, but it is not recommended as definitive therapy. For duodenal obstruction, failure to resolve the obstruction with 1-2 weeks of conservative therapy is an indication for bypass. The operation of choice is a gastrojejunostomy. Not uncommonly, combined obstruction of the pancreatic duct, common bile duct, and duodenum will develop. Combined drainage procedures or resection are used to manage these problems.
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PMID:Management of biliary and duodenal complications of chronic pancreatitis. 1453 24


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