ISSN:0267-1379    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Overlapping neural, hormonal, and paracrine pathways finely regulate gastric acid secretion. In rats and guinea pigs, most of the intrinsic neural innervation to the gastric mucosa originates in the myenteric plexus. In contrast, human stomachs have a clearly defined submucosal plexus that contains a variety of transmitters including nitric oxide, vasoactive intestinal peptide (VIP), gastrin-releasing peptide (GRP), substance P, and calcitonin gene-related peptide (CGRP). Although GRP is known to participate in meal-stimulated acid secretion by releasing gastrin in a variety of laboratory animals, recent studies were unable to demonstrate a role for endogenous GRP in meal-stimulated gastrin secretion in humans. Pituitary adenylate cyclase-activating polypeptide (PACAP), a member of the secretin–glucagon–VIP family, has been localized to gastric mucosal neurons and may participate in vagally mediated acid secretion. Two novel peptides, ghrelin and leptin, have been localized to the stomach. Peripheral administration of ghrelin stimulates and of leptin inhibits acid secretion. The binding of secretagogues to parietal cells generates changes in second messengers that regulate the translocation and activation of the proton pump, H+K+-ATPase. In resting cells, H+K+-ATPase is contained within cytoplasmic tubulovesicles in an inactive form. At stimulation, the tubulovesicles fuse with the apical canaliculi and the H+K+-ATPase is incorporated into the apical membrane where it actively pumps H+ions in exchange for K+. Acute infection withHelicobacter pyloriresults in hypochlorhydria, whereas chronic infection can cause either hypo- or hyperchlorhydria, depending on the distribution of the infection and the degree of corpus gastritis. Recent studies suggest that inflammatory cytokines, produced in response to the organism, can play a role in the perturbations in acid and gastrin secretion induced byH. pylori.

ISSN:0267-1379    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

The mechanisms by which the gastroduodenal mucosa maintains viability and normal functioning despite its intensely caustic environment have puzzled clinicians and investigators alike for at least 150 years. Protective mechanisms have been divided into three main categories: preepithelial (mucus and bicarbonate secretion), epithelial (cellular buffering, mucosal architecture and permeability), and postepithelial mechanisms (mucosal blood flow). Within each category are many other factors that bear on the ability of the mucosa to withstand constant changes of luminal pH. We will summarize some of the recent findings that pertain to the nature and regulation of these defense mechanisms in the context of a historical overview. Therapeutic implications of these findings will also be presented in the discussion of novel antiinflammatory compounds designed to upregulate simultaneously several defensive mechanisms, with the expectation that gastroduodenal damage will be minimized.

ISSN:0267-1379    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

We review papers on nonsteroidal antiinflammatory drugs (NSAID) and the stomach published in the 12 months ending April 2002. During this period, some further developments occurred in the ongoing search for safer antiinflammatory drugs. The highly selective COX-2 inhibitors (COX-2i) have again exhibited some toxicity in animal models of repair, but continue to seem a safer alternative than nonselective inhibitors from the standpoint of the production of human ulcers. Some data on the gastrointestinal safety of valdecoxib and parecoxib are available, while co-therapies with acid suppressants to reduce the risk of conventional NSAID also remain an option (a study comparing lansoprazole with misoprostol is now published). Whether co-prescribing a proton pump inhibitor with a COX-2i in patients at higher risk is effective or justified awaits the results of yet to be completed studies. The nitric oxide (NO)-donating NSAID and NO-donating aspirin show some distinct promise in animal studies and early-phase clinical trials.

ISSN:0267-1379    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

The introduction of the “Maastricht 2–2000” document provides some guidance with regard to the management ofHelicobacter pyloriinfection in both primary and specialist practice settings, albeit primarily in the European setting. The putative role ofH. pyloriin gastric carcinogenesis was supported by a further study. Studies on the natural history of peptic ulcer disease (PUD) highlight the particular vulnerability of the elderly patient to PUD and its complications, and focus attention on targeted intervention in this group, particularly the avoidance of nonsteroidal antiinflammatory drugs (NSAID). Little has evolved with regard to the introduction of new NSAID, but reports indicate the potential association of cyclooxygenase-2 (COX 2)-selective agent use with an increased risk of cardiovascular events. The role ofH. pyloriand NSAID as risk factors for peptic ulcer disease and its complications is again explored, and both meta-analysis and clinical studies provide some evidence of their synergistic effect. The introduction of esomeprazole, the S-isomer of omeprazole, has widened the clinician's therapeutic choice; the true value of this agent remains to be determined.

ISSN:0267-1379    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Technologic milestones have been achieved in the field of interventional endoscopy. These have resulted in improved hemostasis, more accurate cancer staging, safer and less invasive methods of removing gastric neoplasms, and endoscopic palliation of malignant gastric outlet obstruction via stenting. However, just as these milestones are achieved, new challenges emerge: (1) How much sedation can one use safely? (2) What is the risk of transmitting infection and how can that be prevented? (3) Can scopes be made smaller and more comfortable? (4) Can optics be improved? (5) Can endoscopic repair of gastric perforations be safely performed? In this section, we review some of these issues. First, we will provide an update on the most recent concepts in the field of light sedation and infection control. Then, a review of the most commonly used interventional endoscopy procedures, including hemostasis, endosonography, endoscopic mucosal resection, stenting, and percutaneous gastrostomy tube placements. Finally, an overview of the ongoing research and development in the field of interventional endoscopy and how it can improve patient comfort, diagnostic accuracy, therapeutic efficacy, and training in the future.

ISSN:0267-1379    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Most significant research relating to gastric surgery in the past year has centered on surgery for gastroesophageal reflux disease (GERD). Antireflux surgery has become more popular with advanced laparoscopic technology. Two previously accepted surgical principles have been challenged by current studies: the importance of division of the short gastrics and the dictum that partial fundoplication is preferred for patients at risk for dysphagia. Additionally, risk factors for postoperative dysphagia have been identified, allowing for better patient selection and education. Further study on the cause of GERD has shown a positive correlation between pathologic gastroesophageal reflux and those with hiatal hernia or disordered esophageal peristalsis, although cause or effect has not yet been established. Literature relating to bariatric surgery has confirmed the safety and efficacy of the laparoscopic Roux-en-Y gastric bypass, and several papers address the appropriateness of prophylactic cholecystectomy in these patients. The role of laparoscopic surgery for treatment of perforated peptic ulcer disease has now been validated, with subsequent eradication ofHelicobacter pyloriinfection. The relationship ofH. pyloriinfection to acutely bleeding ulcers is less clear. Indications for ulcer surgery are predominantly limited now to perforation and bleeding because of the availability of effective acid-reducing medications and recognition of the role ofH. pyloriinfection.

ISSN:0267-1379    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Disorders of the stomach represent a significant portion of the practice of pediatric gastroenterology. Controversy still exists in the appropriate management of children with abdominal pain and vomiting and large gaps remain in our understanding of the physiology and pathophysiology of the stomach in children. Nevertheless, we have made significant progress in understandingHelicobacter pyloriinfection and gastric motility in the pediatric population.

ISSN:0267-1379    

出版商:OVID    

年代:2002

数据来源: OVID

ISSN:0267-1379    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Diarrhea is a common sequela of deregulated immune pathways underlying the wide range of intestinal acute and chronic diseases. The ongoing investigation of novel immune components and susceptibility factors allows better understanding of these pathologic mechanisms and continues to advance therapeutic options.

ISSN:0267-1379    

出版商:OVID    

年代:2002

数据来源: OVID