1. Volume 121, Issue 6, Pages 1320-1328 (December 2001)
Epithelial barrier defects in ulcerative colitis: Characterization and quantification by electrophysiological imaging 
Alfred H. Gitter, Friederike Wullstein, Michael Fromm, Jörg Dieter Schulzke 
Gastroenterology 
Volume 121, Issue 6, Pages (December 2001)
DOI: /gast
Copyright © 2001 American Gastroenterological Association Terms and Conditions

2. Fig. 1
Low-resolution conductance scanning. Electric current was applied across the colonic wall while mounted horizontally in an Ussing-type chamber. A probe consisting of 2 microelectrodes recorded the vertical voltage drop in the mucosal bath solution at various horizontal positions 100 μm above the surface. The differential amplifier of the probe was connected to an AC bridge system with synchronous demodulation. Thus, the spatial distribution of local conductivity was recorded in 2-dimensional scans of 2.5 · 3.0 mm2 of the mucosa.
Gastroenterology  , DOI: ( /gast )
Copyright © 2001 American Gastroenterological Association Terms and Conditions

3. Fig. 2
Morphologic alterations leading to local increases of permeability. (Left) Histology of H&E-stained sigmoid colon. Note that the pictures were not selected for quality, but taken from the sites that were marked after recording. (Right) The corresponding scan of transepithelial conductivity. The local conductivity, measured in 6 · 6 or 6 · 7 points, is graphed as the intersections of a 3D Cartesian mesh grid; x- and y-coordinates describe the position in the mucosal surface. (A) In control tissue, surface and crypts are covered by an intact monolayered epithelium. In this specimen, the distribution of conductivity was even. (B) UC specimen with mild inflammation. The mucosa showed mild crypt rarefaction, but visible epithelial lesions were absent, although the local conductivity increased dramatically in a local leak (cf. Figure 5). (C) UC specimen with severe crypt deformation and rarefaction. The conductivity seemed normal where the tissue was covered by confluentepithelium (ep), but it was higher at anerosion (E). (D) UC specimen with severe crypt deformation and rarefaction. The conductivity was elevated in the regenerative epithelium above anoedematous lamina propria (O), and increased dramatically at a localerosion (E).
Gastroenterology  , DOI: ( /gast )
Copyright © 2001 American Gastroenterological Association Terms and Conditions

4. Fig. 5
H&E-stained cross-section of a colonic crypt (upper region) at the site of a leak in a UC specimen with mild inflammation, i.e., in the absence of gross epithelial lesions. Several apoptotic fragments can be seen (arrows).
Gastroenterology  , DOI: ( /gast )
Copyright © 2001 American Gastroenterological Association Terms and Conditions

5. Fig. 3
Parameters describing the conductivity of sigmoid colon in controls (n = 8), and in UC tissue with mild inflammation (I, n = 4), or with severe inflammation (II–III, n = 8). The experimental data are presented in the order of increasing overall conductivity. (A) Overall conductivity, as would have been measured in a conventional Ussing chamber; (B) basal conductivity, measured in flat areas without leaks; (C) range of conductivities recorded in each tissue, and the median (crossed).
Gastroenterology  , DOI: ( /gast )
Copyright © 2001 American Gastroenterological Association Terms and Conditions

6. Fig. 4
Conductivity in a UC tissue with severe inflammation (Truelove III). (Left) Histology; (Right) the corresponding scan of conductivity and the surface profile. The probe was moved, in steps of 200 μm, over a distance of 1600 μm, from a large ulcer-type lesion towards a tissue region covered with an intact epithelium. The conductivity (●) decreased, and simultaneously, surface height (○), a measure of mucosal thickness, increased.
Gastroenterology  , DOI: ( /gast )
Copyright © 2001 American Gastroenterological Association Terms and Conditions