ISSN:0267-1379    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Continuing progress is being made in understanding the regulation of pancreatic acinar cell function by receptor-activated intracellular signaling mechanisms. Knowledge of how ligands interact at the molecular level with their receptors and activate heterotrimeric G proteins is increasing. In addition to inositol trisphosphate, intracellular messengers include cyclic ADP ribose, nicotinic acid adenine dinucleotide phosphate, arachidonic acid, and diacylglycerol. Ca2+signaling involves the interaction of inositol trisphosphate, cyclic ADP ribose, and nicotinic acid adenine dinucleotide phosphate with distinct subcellular Ca2+stores. Ca2+signals ultimately induce exocytosis of zymogen granules and identification of the proteins involved on the granule and plasma membrane, and understanding of their roles is continuing. Other receptor-activated signaling pathways primarily regulate nonsecretory events. Considerable progress has been made in understanding how the mammalian target of rapamycin pathway regulates protein synthesis through translation factors and ribosomal proteins. Other pathways in acinar cells include the mitogen-activated protein kinases, the tyrosine kinases, and the transforming growth factor-&bgr;–Smad pathways.

ISSN:0267-1379    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

The neurohormonal control of pancreatic exocrine secretion is a complex interaction of multiple pathways involving a large number of gut hormones, neurotransmitters, and neuropeptides. Recent studies have elucidated a role for cholecystokinin in the regulation of bicarbonate and fluid secretion from pancreatic duct cells and suggested that cholecystokinin stimulation of human pancreatic acinar cells is likely regulated by an indirect mechanism of stimulation of afferent neurons. Evidence supports the regulation of potassium channels in rat pancreatic acinar cells by the cyclic AMP–mediated agonist secretin. Mechanisms for the regulation of cholecystokinin and secretin release by releasing factors have also been elucidated. The area postrema has been implicated in the mediation of inhibition of pancreatic secretion by the gut hormones peptide YY and pancreatic polypeptide. The neurotransmitter serotonin has been demonstrated to play a role in acid-induced secretin release and in pancreatic secretion stimulated by luminal factors. The regulation of pancreatic exocrine secretion by purines, nitric oxide, and &ggr;-aminobutyric acid as well as by the neuropeptides pituitary adenylate cyclase–activating peptide, gastrin-releasing peptide, and substance P is reviewed. The role of the central nervous system in modulating pancreatic secretion is also described. This review highlights the recent advances in knowledge of the neurohormonal regulation of pancreatic exocrine secretion.

ISSN:0267-1379    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

The recognition that variations in the DNA sequence of key genes predispose individuals to acute pancreatitis, chronic pancreatitis, and pancreatic cancer represents one of the greatest breakthroughs in pancreas research. This review highlights recent progress in understanding mutations in the cationic trypsinogen gene, the pancreatic secretory trypsin inhibitor gene, and the cystic fibrosis transmembrane conductance regulator gene with respect to pancreatitis. It also notes progress in the use of microarray technology, classification of chronic pancreatitis, and predisposition to pancreatic cancer.

ISSN:0267-1379    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Acute pancreatitis begins as acute pancreatic injury and may generate a systemic inflammatory response that evolves into multiorgan failure, leading to death. Multiple inciting factors such as toxins (alcohol), gallstones, or endoscopic retrograde cholangiopancreatography result in a cascade of events beginning with the intra-acinar activation of zymogens and the release of cytokines and other proinflammatory mediators. Their release is a major determinant of the systemic inflammatory response and distant organ failure. Attempts to attenuate the severity of acute pancreatitis by blocking specific inflammatory mediators have had limited success. This review is divided into experimental acute pancreatitis and clinical acute pancreatitis. The distinction is maintained because although animal models of disease have helped define the pathogenesis of acute pancreatitis, they do not completely reproduce the clinical syndrome of human acute pancreatitis or guarantee equal success of therapies in humans.

ISSN:0267-1379    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

The pathogenesis of idiopathic chronic pancreatitis remains poorly understood despite the high expectations for ascribing the pancreatic damage in affected patients to genetic defects. Neither mutations in the cationic trypsinogen gene nor mutations of the cystic fibrosis conductance regulator gene account for the chronic pancreatitis noted in most patients with idiopathic chronic pancreatitis. Attempts to find an autoimmune basis for the pancreatitis in these patients have not been very successful. The diagnosis of small duct idiopathic chronic pancreatitis remains a great source of frustration for clinicians. Such patients with negative results of radiographic studies often cannot be diagnosed unless a hormone stimulation test such as a secretin test is performed. Although the porcine biologic form of secretin, which has been used to diagnose chronic pancreatitis, became unavailable because of widespread use in the treatment of children with autism, a synthetic form of porcine secretin has now been approved by the US Food and Drug Administration and is available. The true value of endoscopic ultrasonography in diagnosing small duct chronic pancreatitis remains to be fully defined. Endoscopic ultrasonography is becoming the test of choice in detecting radiographic abnormalities in both the parenchyma and ducts of the pancreas. Endoscopic ultrasonography–guided celiac plexus block can be performed relatively easily and very safely. It can provide excellent short-term pain relief in some patients, but reliable predictors of which patients will be successful with this therapy are not yet available. Because long-term follow-up data on the use of endoscopic ultrasonography in this respect are not available, and because the pain of chronic pancreatitis is, indeed, chronic, the role of endoscopic ultrasonography–guided celiac plexus block should be limited to treating those patients with chronic pancreatitis whose pain has not responded to other modalities.

ISSN:0267-1379    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Advances in the scientific knowledge and medical management of pancreatic cancer are lagging behind significant discoveries in other tumors. From 2001 to 2002, the period covered by this review, few but yet important findings have continued to push this field of medicine ahead. However, the most promising advance made in pancreatic cancer is the increased awareness of this disease by private and federal agencies as well as the population at large. In addition, there has been a remarkable increase in scientific communication among different research groups around the country. National cooperation among government, philanthropic organizations, advocacy groups, and scientists offers for the first time a framework of hope regarding the establishment of a comprehensive plan to fight this dismal disease. Scientists have responded with renewed enthusiasm, which has resulted in significant advances in two exciting areas of wide interest in the field—genetic animal models and postgenomic mechanisms of pancreatic carcinogenesis. The questions that these studies address and their potential impact on this field of research are highlighted here.

ISSN:0267-1379    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Over the past year considerable progress has been made in the field of pancreatic surgery. Innovative diagnostic techniques continue to improve the preoperative staging of pancreatic cancer. For patients with cancer and biliary obstruction, preoperative biliary stenting appears to increase the incidence of wound infection after pancreatoduodenectomy but has no effect on other perioperative complications. New information about the molecular biology of pancreatic cancer may begin to influence the surgical approach to the disease. More cases of intraductal papillary mucinous neoplasms are being diagnosed and studied. The impact of adjuvant chemotherapy and chemoradiation on survival has been more clearly defined in a large, randomized trial. In patients with sterile acute necrotizing pancreatitis, conservative nonsurgical management has continued to produce favorable results. For chronic pancreatitis, surgery appears to diminish both chronic pain and recurrent episodes of acute pain.

ISSN:0267-1379    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Endoscopic ultrasound is an established modality for staging gastrointestinal and pancreatic malignancies. Since the development of the linear array echoendoscope, the field of interventional endoscopy has continued to evolve as an adjunctive method to standard endosonography. The ability to sample extraluminal lesions or lymph nodes has overcome the initial limitations of endoscopic ultrasound and provided a list of attractive endoscopic ultrasound-guided therapeutic applications.This review focuses on recent advancements in the field of interventional endosonography related to the diagnosis and therapy of pancreatic diseases. In particular, the article reviews the role of endoscopic ultrasound–guided fine-needle aspiration in diagnosing various pancreatic diseases; the role of endoscopic ultrasound–guided fine-needle injection in delivering neurolytic, chemotherapeutic, or biologic agents; and emerging procedures like endoscopic ultrasound–assisted biliary bypass in the setting of malignant biliary obstruction.

ISSN:0267-1379    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Endoscopic detection of dysplasia currently requires either the presence of a visible lesion (such as a polyp) or the serendipitous sampling of a dysplastic focus during “blind” surveillance biopsies. To accurately and efficiently examine large areas of mucosa during surveillance endoscopy, new methods are required to render dysplasia visible. Spectroscopy and optical coherence tomography are two technologies under active investigation for this purpose. This review presents the basic concepts behind these technologies and discusses their utility in the detection of gastrointestinal dysplasia.

ISSN:0267-1379    

出版商:OVID    

年代:2002

数据来源: OVID