This study provides clear evidence from viable endoscopic colorectal samples that mast cell mediators were secreted during active inflammation in CD and UC. However, the extent of mast cell involvement and activation differs considerably between CD and UC. Significantly increased rates of tryptase secretion were found both in non-inflamed and inflamed tissue of UC, indicating that mast cell involvement is a typical feature of UC.

No abstract

Developmental prosopagnosia (DP) is commonly associated with the failure to properly perceive individuating facial properties, notably those conveying configural or holistic content. While this may indicate that the primary impairment is perceptual, it is conceivable

Evidence has accumulated to support a model for odorant detection in which individual olfactory receptor neurons (ORNs) express one of a large family of G protein-coupled receptor proteins that are activated by a small number of closely related volatile chemicals. However, the issue of whether an individual ORN expresses one or multiple types of receptor proteins has yet to be definitively addressed. Physiological data indicate that some individual ORNs can be activated by odorants differing substantially in structure and/or perceived quality, suggesting multiple receptors or one nonspecific receptor per cell. In contrast, molecular biological studies favor a scheme with a single, fairly selective receptor per cell. The present studies directly assessed whether individual rat ORNs can express multiple receptors using single-cell PCR techniques with degenerate primers designed to amplify a wide variety of receptor sequences. We found that whereas only a single OR sequence was obtained from most ORNs examined, one ORN produced two distinct receptor sequences that represented different receptor gene families. Double-label in situ hybridization studies indicated that a subset of ORNs co-express two distinct receptor mRNAs. A laminar segregation analysis of the cell nuclei of ORNs labeled with the two OR mRNA probes showed that for one probe, the histogram of the distribution of the cell nuclei along the depth of the epithelium was bimodal, with one peak overlapping the (unimodal) histogram for the other probe. These results are consistent with co-expression of two OR mRNAs in a population of single ORNs.

IntroductionThe term food allergy (FA) is defined as an immune-mediated hypersensitivity to ingested allergens. This immunologic response to nutritive antigens in the intestine is mostly an immediate type hypersensitivity depending on food-specific IgE-antibodies [1]. Food antigen and IgE-antibody crosslinking causes mast cell and eosinophil degranulation with subsequent release of histamine (H) and other mediators like leukotrienes, prostaglandins and platelet activating factor at the mucosal surface of the gut [2]. Histamine might influence the occurrence and severity of intestinal as well as extraintestinal symptoms and their duration. In the intestine H is catabolized by the enzymes diamine oxidase (DAO) and histamine-N-methyltransferase (HNMT) which are present in the epithelial cells of the small and large bowel [3]. In this context, the aim of this study was to investigate the distribution and activity of DAO in the intestinal mucosa of healthy persons and patients suffering from FA. Materials and methodsThe study involved 12 patients with manifest FA complaining of chronic or intermittent diarrhoea (100%), abdominal pain and/or bloating (55%), vomiting and/or malabsorption (25%) and urticaria, flush or skin reactions (20%). They had colonoscopy in order to exclude other gastrointestinal diseases. In all cases, diagnosis of FA was confirmed by double-blind, placebo-controlled oral food challenge (DBPCFC) and by demonstration of food-specific IgE-antibodies in blood, skin or intestinal lavage fluid [4]. In the control group (CG), 11 individuals were included who underwent colonoscopy because of obstipation, workingup of anaemia or abdominal pain without any abnormal endoscopic or histologic findings in the lower gastrointestinal tract and without allergic diseases.The endoscopically taken biopsies (n = 64/FA, n = 57/CG) were stored immediately in liquid nitrogen. They were homogenized with 1500 ml phosphate buffer (1500 rpm, 5 min, micro-dismembrator, Braun Biotech, Germany) and centrifuged (7500 rpm = 2500 g, 4°C, 10 min). DAO activity was measured in the tissue homogenates (supernatants) adding 14 C-putrescine as substrate according to the method of Kusche et al. [5]. The DAO activity was given in cpm/hour ¥ mg wet weight (ww), mean ± SD. Intraassay variation of the DAO-assay was 16.2 %. In addition, total histamine degradation capacity (THDC, D ng histamine degradation/hour ¥ mg ww, mean ± SD, intraassay variation = 8.5 %), reflecting the enzyme activity of all histamine catabolizing enzymes, was determined from each tissue homogenate. Therefore, the histamine content was measured in duplicate at t 0 and after 60 min in 100 ml aliquots (37°C) by radioimmunoassay (Coulter-Immunodiagnostics, Germany, intraassay variation = 11.8 %, interassay variation = 21.2 %). Enzymatic histamine degradation was stopped by denaturating the enzymes by 100 ml perchloric acid (8 %) at t 0 and t 60 , respectively. For statistics the U-Test (Mann-Whitney-Wilcoxon) for independent data was used. Results and discussionIn patien...