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Biomedical subjects

D Schwab

Publications and source records attributed to D Schwab.

At least 19 recordsLinked to original sources
PubMed2001

[Pathobiology of dysplasia in chronic inflammatory bowel disease: Current recommendations for surveillance of dysplasia].

Pathobiology of dysplasia in chronic inflammatory bowel disease: Current recommendations for surveillance of dysplasia. Patients with ulcerative colitis and Crohn's disease bear an about 10- and 4-fold increased risk, respectively, for developing colorectal carcinoma. Apart from typical locations of colorectal carcinoma in the sigmoid colon and rectum other locations were also often observed, e. g. right hemicolon or multifocal distribution. Histologically colorectal neoplasms frequently present as mucinous adenocarcinoma (signet-ring cell carcinoma). The risk for neoplasm depends on extension, severity, duration and therapeutic responsiveness of chronic colonic inflammation, and it seems pathogenetically to be similar in ulcerative colitis and Crohn's disease. Colorectal carcinoma in inflammatory bowel disease arises from epithelial dysplasia. Since there are no reliable biological markers available to date, surveillance-programs continue to rely on the discovery of dysplasia (unequivocal intraepithelial neoplasia). Detection of dysplasia by colonoscopy achieves 70-85 % sensitivity.Endoscopic surveillance should start after 8 years of disease's duration in pancolitis, after 10-12 years in left- sided colitis and after 12 years in Crohn's disease of the colon, with regular intervals every 1-2 years. 3-5 biopsies should be done every 10 cm from mucosa free of inflammation. Additionally, every fine or discrete alteration of the mucosal surface should be recorded. Multiple biosies should also be taken from such minimal lesions as well as from more macroscopically suspicious areas like plaques, nodular lesions or stenosis. The clinical consequence of a positive screening for dysplasia is colectomy because of an assumed risk of cancer of about 40-70 %. Dysplasia in macroscopically suspect areas bear the highest risk of cancer (non-adenoma like dysplasia), followed by multiple high-grade lesions without a macroscopic lesion, and multiple low-grade dysplasias. Detection of single dysplastic lesions in flat mucosa should be followed by a control endoscopy after 2-6 months, and if dysplasia is seen again, colectomy is recommended.

Adenocarcinoma, Mucinous↗
PubMed2001

Immunoglobulin E and eosinophilic cationic protein in segmental lavage fluid of the small and large bowel identify patients with food allergy.

OBJECTIVE: Members of the general population often assume that they suffer from food allergy, but the true prevalence is low. Testing for the diagnosis of food-related hypersensitivity entails laborious procedures, including GI endoscopy. Our objective was to develop an endoscopic screening approach for food allergy. METHODS: Endoscopically guided segmental lavage was performed in 11 patients with GI allergy and in 20 controls during lower GI endoscopy of the terminal ileum, the coecum, and the rectosigmoid. Eosinophilic cationic protein (ECP) and protein were measured in native lavage fluid, and immunoglobulin E (IgE) was also measured after a 10-fold lavage concentration. RESULTS: IgE/protein in lavage fluid from the coecum (0.055 +/- 0.068 U/mg vs 0.003 +/- 0.012 U/mg; p = 0.001) and the rectosigmoid (0.134 +/- 0.170 U/mg vs 0.019 +/- 0.042 U/mg; p < 0.05) was significantly elevated in patients with GI allergy. ECP/protein was significantly elevated at the terminal ileum (22.95 +/- 37.67 microg/mg vs 7.09 +/- 7.68 microg/mg; p < 0.05) and the rectosigmoid (23.66 +/- 19.43 microg/mg vs 11.97 +/- 16.39 microg/mg; p < 0.05). The combined use of GI lavage IgE and ECP as a diagnostic test for food allergy resulted in a sensitivity of 91% and a specificity of 80%. CONCLUSIONS: In endoscopically guided segmental lavage fluid, IgE and ECP/protein are increased in patients with food allergy. These measurements seem to offer an attractive diagnostic tool and may serve as a screening method.

Adult↗
PubMed2001

Hepatic uptake of synthetic chlorogenic acid derivatives by the organic anion transport proteins.

Chlorogenic acid derivatives were recently identified as novel, potent, and specific inhibitors of the hepatic glucose 6-phosphate translocase. Inhibition of the glucose 6-phosphate translocase leads to a decrease in hepatic glucose production, rendering chlorogenic acid derivatives as potential novel therapeutics in patients with type 2 diabetes. The present study examines the hepatic uptake mechanism of the radiolabeled chlorogenic acid derivative S 1743 into freshly isolated rat hepatocytes. Initial uptake rates were Na(+)-independent and followed saturation kinetics with no superimposition of facilitated diffusion. Inhibition studies demonstrated that other chlorogenic acid derivatives inhibited uptake of the radiolabeled compound S 1743 into rat hepatocytes in the range of 1.1 to 11 microM, whereas the natural chlorogenic acid (up to 100 microM) had no effect at all. In addition, inhibition of S 1743 uptake into rat hepatocytes was found in the presence of sulfobromophthalein, sulfolithocholyltaurine, estrone-3-sulfate, cholyltaurine, verapamil, bumetanide, probenecide, phenol red, digoxin, and ouabain (in decreasing order) but not with N-methylnicotinamide, alpha-ketoglutarate, p-aminohippurate, geneticin sulfate, and 5-sulfosalicylate. The observed inhibition pattern suggested that members of the family of the organic anion transporting polypeptides (Oatps) could be involved in hepatic uptake of chlorogenic acid derivatives. Indeed, S 1743 uptake could be demonstrated in Oatp1- and Oatp2-expressing Xenopus laevis oocytes as well as in Oatp1-expressing Chinese hamster ovary cells. A comparison of the inhibition pattern obtained in hepatocytes compared with that obtained in Oatp1-expressing Chinese hamster ovary cells suggests that facilitated uptake by Oatp1 is a major contributor in total hepatic uptake of chlorogenic acid derivatives.

Animals↗
PubMed2000

A preliminary study of spatial distribution and mating system of pygmy mouse lemurs (Microcebus cf. myoxinus).

According to current hypotheses on the evolution of life history traits and social systems of Malagasy lemurs, nocturnality is associated with a solitary lifestyle and a polygynous or promiscuous mating system. Recent studies, however, have indicated that this may not be true of all lemurs. The goal of this study was to investigate the sociality and the mating system of pygmy mouse lemurs (Microcebus cf myoxinus), which are the smallest known primates, and which retain characteristics of the most primitive primates. I compared my findings with data on the sympatric Microcebus murinus and Cheirogaleus medius. Observational, morphometric and spatial distribution data were obtained by a radiotracking study in 1994, and from a capture-recapture study conducted during 1995/96. Pygmy mouse lemurs usually slept alone in a tangle of vegetation. During the mating season, sleeping sites of males were distributed over a much broader area than were female sites, indicating that male home ranges are larger than those of females. The home ranges of males overlapped during the mating season, and males occasionally roamed over long distances during a single night. Pygmy mouse lemurs forage primarily alone. Analysis of estrus stages indicate that female cycles are unsynchronized during the mating season. There was a lack of sexual dimorphism in body size but not in body mass. Males were heavier than females during the reproductive season but lighter than females the rest of the year. Testes of males varied in size seasonally and enlarged significantly during the mating season. The presence of a vaginal sperm plug in a female indicated the importance of preventing additional matings in this species. Thus pygmy mouse lemurs follow the predictions derived from sexual selection theory for multi-male mating systems with promiscuous matings and male sperm competition.

Animals↗