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Short-term exposure to nicotine does not alter normal basal or NSAID-induced gut barrier function or transit. 51Cr-EDTA and the respective sugar markers correlate well in in vivo permeability testing in healthy humans. The radioactive test detects more NSAID-induced permeability increase than does the lactulose/mannitol ratio permeability test.

Background: Smoking modulates inflammatory bowel disease, protecting from ulcerative colitis on the one hand and worsening the course of Crohn’s disease on the other. This influence might occur through changes in intestinal permeability, because permeability is increased in most patients with Crohn’s disease. Aim: To study the influence of smoking on small intestinal permeability and its increase induced by indomethacin. Methods: 50 smokers and 50 nonsmokers underwent a 51Cr‐EDTA basal permeability test and the same test after challenge with indomethacin 125 mg p.o. Results: Small intestinal permeability was the same in smokers (median 1.22%; IQR 1.00–1.58) and nonsmokers (1.24%; 0.94–1.66). Basal small intestinal permeability was lower in females (1.09%; 0.87–1.33) than in males (1.48%; 1.18–1.88). Indomethacin challenge increased permeability by 110% (71–141) in smokers, vs. 156% (78–220) in the nonsmokers (P=0.04). Conclusion: Smoking reduces the effect of NSAID on small intestinal permeability. It is therefore unlikely that the adverse effect of smoking on Crohn’s disease is related to its influence on intestinal permeability.

An evaporative light scattering detector (ELSD) coupled with HPLC was used for the first time to characterize membranes. Polydispersed PEG-200, 600, and 1000 were selected as probe molecules to study the dependence of membrane retention on molecular weight via a gradient eluted HPLC separation coupled to ELSD detection. The results show that HPLC/ELSD is a really general and powerful technique to study the nanofiltration (NF) process since it does not require any special properties for the solutes (chromospheres or fluorophores) and possesses the required sensitivity. Especially in solvent resistant NF (SRNF), where a wide range of organic solvents is used, the ELSD detector was not affected by the interaction between solvent and solutes, which is a critical issue compared to other more common detectors.

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