ISSN:0267-1379    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The cause or causes of ulcerative colitis and Crohn's disease remain obscure, but advances in the understanding of inflammation and its mediators have now translated into practical applications. There is increasing evidence that intestinal mucosal inflammation is mediated by cytokines, chemokines, and other inflammatory mediators that affect the recruitment of inflammatory cells. Standard medical therapy for inflammatory bowel disease uses drugs with a variety of anti-inflammatory effects and poorly defined molecular targets. These advances in understanding of the mechanisms of mucosal inflammation in inflammatory bowel disease have provided a means for the development of specific immuno-modifying treatments based on anti-cytokine strategies. The role of cytokines in the pathophysiology of inflammatory bowel disease may be equally large in ulcerative colitis and in Crohn's disease, but therapeutic interventions are most vital in Crohn's disease, where surgical cure is never certain. A better understanding of the role of cytokines in these diseases will also help explain the mechanism behind successful traditional treatments. Although some therapies are used in both conditions, we will organize our discussion on advances in medical therapy for inflammatory bowel disease in 1997 largely by disease.

ISSN:0267-1379    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Patients with long-standing extensive ulcerative colitis have an increased risk of colorectal cancer compared with the general population, and the carcinoma is frequently preceded by dysplasia. Molecular markers such as Ki-67, DPC-4, and DYS nuclear matrix proteins may potentially be useful for further refining the diagnosis of dysplasia, or may even eventually provide an alternative method of predicting colorectal cancer. If DYS nuclear matrix proteins prove to be reliably restricted to dysplasia and cancer, their identification in tissues or even serum could be immensely useful. Clinical studies provide further support to the increasingly prevalent recommendation that any dysplasia warrants colectomy. Chemopreventive methods, such as supplementation with folic acid, may help reduce the incidence of neoplasia, but more studies are needed.

ISSN:0267-1379    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The visceral afferents innervating the colon play a significant role in regulatory reflexes and consciously evoked sensations. These afferents travel centripetally in the pelvic and lumbar splanchnic nerves and enter the spinal cord via white rami. Afferents innervating the muscles of the hollow viscera encode graded intensities of intraluminal distension. A large proportion of them have low thresholds for response and a small proportion have high thresholds for response. The complexity of visceral pain cannot be explained fully on the basis of response characteristics of afferents. It can be proposed, however, that in the colon, which gives rise to sensations from fullness to intense pain, activation of low-threshold afferents contribute to regulatory reflexes and nonpainful sensations and activation of low- and high-threshold afferents contribute to acute pain. A prolonged activation and sensitization of both low- and high-threshold and sensitization of previously mechanically insensitive afferents may contribute to the visceral hyperalgesia. Recent studies indicate that k-opioid receptor agonists attenuate visceral hypersensitivity by acting at a peripheral site.

ISSN:0267-1379    

出版商:OVID    

年代:1998

数据来源: OVID

ISSN:0267-1379    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The recent identification of genetic defects responsible for hereditary nonpolyposis colon cancer (HNPCC), together with the refinement and dissemination of techniques that allow the diagnosis of germline DNA mismatch repair defects, has revolutionized the management of this disease. In particular, accurate genotypic identification allows tailoring of colorectal resection in HNPCC patients with established carcinoma, and refinement of strategies of surveillance and prophylaxis prior to malignant transformation. Recent studies have helped to clarify the risk of malignant transformation within specific risk groups. The creation of collaborative registries should allow further clarification of risk factors for intestinal and extraintestinal malignancies.

ISSN:0267-1379    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The ideal operation of rectal cancer excises the disease with minimal morbidity. The traditional abdominoperineal resection approach to rectal cancer was considered the surgical gold standard but significant morbidity in the form of mandatory stomas and nonhealing perineal wounds prompted a search for a better approach. Since about 1940, sphincter-sparing procedures, such as anterior resection, in appropriately selected patients have achieved equal or greater rates of survival and recurrence with the benefit of an improved quality of life. More recently, transanal local excision and coloanal anastomosis have been used with increasing frequency to spare the sphincter and cure the cancer.

ISSN:0267-1379    

出版商:OVID    

年代:1998

数据来源: OVID

ISSN:0267-1379    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

During the last decade research on the molecular pathogenesis of several bacterial intestinal infections has provided substantial knowledge necessary for the introduction of effective vaccines against major pathogens as well as for new diagnostic tools. A number of new and additional virulence factors in different infectious processes have been identified. Interestingly, several mechanisms and virulence factors are shared by bacteria of different species. Culture conditions resembling the environment in the small and the large intestine have been used to identify in vivo expression of various presumptive virulence factors. Although well-known bacterial diarrheal agents like Salmonella spp, Shigella spp, Campylobacter jejuni, and Escherichia coli with different adhesins still constitute a major part of identified infections, we have encountered epidemic outbreaks of Vibrio cholerae serotype O139 and of enterohemorrhagic E. coli O 157:H7. The extent of enterohemorrhagic E. coli infections of serotypes other than 0157:H7 remains largely unknown.

ISSN:0267-1379    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Viral gastroenteritis continues to be a major worldwide public health problem. The number of pathogens identified continues to increase, and better characterization of the viruses is inexorably pursued. However, investigators are still in the process of determining the mechanisms of virus-cell interactions, host responses, and pathogenesis. Despite deficiencies in knowledge of many aspects of these important issues, progress on a vaccine for the most important pathogen, rotavirus, has been significant.

ISSN:0267-1379    

出版商:OVID    

年代:1998

数据来源: OVID