ISSN:0267-1379    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

A major limitation in understanding the pathogenetic mechanisms responsible for the intestinal or colonic mucosal injury and dysfunction observed in inflammatory bowel disease (Crohn's disease, ulcerative colitis) is the relative lack of animal models that exhibit the chronic, spontaneously relapsing inflammation associated with these idiopathic diseases. Although no animal model has been developed that possesses all of the pathohistologic features of human inflammatory bowel disease, there are several different models available that exhibit some of the characteristics associated with ulcerative colitis or Crohn's disease. This review will focus primarily on some of the most popular models of intestinal or colonic inflammation induced by exogenous agents. The objective of this review is to critically evaluate each model in terms of its clinical and histopathological features, etiologic mechanisms, and responses to certain drug therapies known to be effective in the treatment of human inflammatory bowel disease.

ISSN:0267-1379    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Although much progress has been made in understanding the pathophysiology of inflammatory bowel disease, the precise etiology of Crohn's disease and ulcerative colitis remains unknown. It has been suggested that the complex interactions between an initiating factor and the gut immune system are primarily responsible for the promotion and perpetuation of the chronic inflammation associated with this disease. Because of this, much attention has been focused on studying the role of immunocytes and their inflammatory mediators in the pathogenesis of inflammatory bowel disease. These inflammatory mediators include 1) proinflammatory cytokines (interleukin-1, tumor necrosis factor-α, and interleukin-8), 2) inhibitory cytokines (interleukin-1 receptor antagonist), 3) immunoregulatory cytokines (interleukin-2, interleukin-6, and interferon-γ), 4) lipid mediators (prostaglandin E2, leukotriene B4, and platelet activating factor), 5) oxygen free radicals, and 6) neuropeptides.

ISSN:0267-1379    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Characterization of lymphocyte populations in the intestinal mucosa in inflammatory bowel disease (IBD) has demonstrated expansion of α, β T-cell populations, but as yet no specific abnormality of lymphocyte phenotype or function has been found in IBD. Up-regulation of adhesion molecules on endothelial cells probably is an important first step in mucosal inflammation in IBD. Abnormal IgG and complement deposition in ulcerative colitis suggests a role for antibody-mediated injury to this disease, but not in Crohn's disease. The search for specific antibody abnormalities has focused on antineutrophil cytoplasmic antibodies: until the specific antigen recognized by IBD sera is identified and sensitive, specific and standardized tests are developed, the significance of antineutrophil cytoplasmic antibodies in IBD will remain uncertain. Biochemical studies on a wide range of potential pathologic mechanisms have further characterized the role of mucus, lysozyme, hyaluronan, phospholipases, fatty acids, lipocortin, polyamines, glycosidases, and the coagulation pathway in IBD.

ISSN:0267-1379    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

There is no longer doubt that an increased risk for colon cancer exists in patients with ulcerative colitis. This conclusion is supported not only for cancer of the colon, but for the small bowel and the colon in Crohn's disease. This review covers new data and new ideas about risk factors, the latest observations on dysplasia as a premalignant lesion, recommendations for endoscopic surveillance, and management of the patient with potential cancer based on the outcome of surveillance.

ISSN:0267-1379    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Descriptive surveys of the epidemiology of inflammatory bowel disease from the north and south of Europe show north-south gradient in its incidence and continue to point to lifestyle and environmental causes. This theme is further examined in studies of the causal association between inflammatory bowel disease and smoking, oral contraceptive use, and diet by investigators from the United States and Europe, but the results are not conclusive. Childhood exposure to environmental tobacco smoke and the risk of ulcerative colitis is a new entry to the field that shows decreased risk of ulcerative colitis in passive smokers.

ISSN:0267-1379    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Significant advances have occurred in identifying the types of malnutrition and specific nutrient deficits that adversely affect clinical outcome in patients with inflammatory bowel disease (IBD). Innovative nutritional therapies are being developed to correct these deficits. The traditional clinical practice of prescribing bowel rest for patients with IBD is undergoing rigorous scientific scrutiny. Moreover, it is now hypothesized that in selected patients with IBD, it may be more advantageous to feed into the gut those fuels that are preferentially metabolized by its mucosa rather than to prescribe bowel rest, which starves the gut and produces intestinal atrophy and dysfunction. Examples of these fuels include glutamine, the preferred enterocyte fuel, and butyrate, the major energy source for the colonocyte. Additionally, the ω-3 fatty acids, commonly termed fish oils, provide important immunocompetence to the gut barrier and may benefit patients with IBD. As a result of reduced costs and improved morphologic and functional benefits to the gut, studies in patients with IBD continue to confirm the importance of providing total enteral nutrition rather than total parenteral nutrition.

ISSN:0267-1379    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Diagnosis of ulcerative colitis or Crohn's disease is determined by a combined effort of putting together clinical information with several diagnostic tools (endoscopy, histology, radiology, scintigraphy, ultrasonography, and microbiologic and laboratory tests), which can be also used for assessing disease activity. There is now an increased interest toward new entities such as collagenous and microscopic colitis, although the presence of intestinal tuberculosis should be called into differential diagnosis with Crohn's disease. For assessing disease activity, new interest is focused on the serum level determination of cytokines such as interleukin-1, interleukin-6, tumor necrosis factor-α, and others. In patients with long-standing ulcerative colitis, there is a trend to develop strictures, and the clinical course of Crohn's disease is characterized by a frequent need for surgical procedures. Evaluation of health status represents a further effort of better defining the patient's reactivity toward these chronic illnesses, whereas the economic cost might be of great relevance because of the early onset of these diseases. Inflammatory bowel disease patients might complain of several other associated disorders such as hepatobiliary disease, arthropathies, and others, including intestinal and extraintestinal neoplasias.

ISSN:0267-1379    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Increased intraocular pressure in children receiving corticosteroids for inflammatory bowel disease is an important new complication reported this past year. The incidence of glaucoma is unknown, but this finding suggests that careful ophthalmologic follow-up of children on corticosteroids may be important. A new study of Indium-111 leukocyte scans in children compared favorably with radiographic studies and surgical findings in inflammatory bowel disease. Indium scans may be most useful in the evaluation of small bowel Crohn's disease. Upper intestinal symptoms in Crohn's disease may be related to delayed gastric emptying. In a study of children with inflammatory bowel disease, none with ulcerative colitis, but 30% with Crohn's disease had abnormal gastric emptying. Anemia in children with Crohn's disease is common and may be due to malabsorption. In a recent study, 10 of 11 children with Crohn's disease had malabsorption of iron, whereas only six of the 11 had occult blood loss.

ISSN:0267-1379    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Inflammatory bowel disease comprises a group of idiopathic inflammatory intestinal disorders, ulcerative colitis, and Crohn's disease. It currently afflicts approximately 1 million Americans and has an annual incidence of 70,000 to 100,000 cases in the United States alone. Although the etiologic agents of ulcerative colitis and Crohn's disease remain elusive, we are still able to diagnose and treat these disorders effectively. Crohn's disease has no medical or surgical cure; however, total proctocolectomy is curative for ulcerative colitis. Effective treatment of ulcerative colitis and Crohn's disease depends on a precise diagnosis and determination of the the extent and severity of disease. In this article, the current medical therapies available for treatment of patients with inflammatory bowel disease will be reviewed and the status of other investigative drugs will be assessed.

ISSN:0267-1379    

出版商:OVID    

年代:1993

数据来源: OVID