Debate: should mesalamine be used in Crohn's disease?: comments and conclusions

Mesalamine has a well-established role in the management of ulcerative colitis. However, its role in the management of Crohn's disease (CD) is less clear. Studies evaluating its therapeutic value in CD have produced both positive and negative results. Meta-analyses have not clarified the situation, possibly because they have combined studies of different design. This debate critically examines the evidence for and against the use of mesalamine in CD.     

Multispectral analysis of magnetic resonance images

Magnetic resonance (MR) imaging systems produce spatial distribution estimates of proton density, relaxation time, and flow, in a two dimensional matrix form that is analogous to that of the image data obtained from multispectral imaging satellites. Advanced NASA satellite image processing offers sophisticated multispectral analysis of MR images. Spin echo and inversion recovery pulse sequence images were entered in a digital format compatible with satellite images and accurately registered pixel by pixel. Signatures of each tissue class were automatically determined using both supervised and unsupervised classification. Overall tissue classification was obtained in the form of a theme map. In MR images of the brain, for example, the classes included CSF, gray matter, white matter, subcutaneous fat, muscle, and bone. These methods provide an efficient means of identifying subtle relationships in a multi-image MR study.     

Recent developments in CT colonography

CT colonography allows reliable, non-invasive, rapid, high resolution imaging of the whole large bowel. Recent advances in technology such as computer-aided detection (CAD), scanning with or without bowel preparation, and low radiation are continually developing to improve the efficacy of this technique. This review will update the reader as to ongoing developments while presenting current thinking from the gastroenterological perspective.     

Variation of peptide transporter (PepT1 and HPT1) expression in Caco-2 cells as a function of cell origin

Caco-2 cell cultures are a widely used in vitro model for the small intestinal drug transport, although large differences have been reported for actively transported substrates from different laboratories. Therefore, we compared three different Caco-2 clones: (1) from the American Culture Tissue Collection (ATCC), (2) from the German Cancer Research Center (DKFZ) in Heidelberg, and (3) from the University Hospital in Marburg in different passage numbers regarding their morphology, multilayers, and tight junction formation, as well as expression of the peptide transporters, HPT1 and PepT1. We determined tight junction formation by measurement of the transepithelial electrical resistance, multilayer formation by confocal laser scanning microscopy, the expression of PepT1 and HPT1 by RT-PCR, indirect immunofluorescence and the permeability of the PepT1 substrate, cephradine. Morphology and TEER-values varied strongly between the different clones. The expression of PepT1 and HPT1 increased in the following order: HD > ATCC > MR. Indirect immunofluorescence revealed a heterogeneous distribution of the transporters in ATCC-cells, whereas it was homogeneous in HD-cells. Only a very weak expression was found in MR-cells. While in ATCC-cells expression of transporters decreased with increasing passage number, it increased in HD-cells. Expression levels were congruent with the transport of cephradine. Expression of PepT1 and HPT1 was strongly affected by the culture conditions. Under identical culture conditions, Heidelberg (HD) Caco-2 cells seemed to be an appropriate in vitro cell culture model for the transport of actively transported drugs, because interpassage changes are low and the transporter distribution was homogeneous throughout the monolayer.