RESUMO
Postinfectious IBS is defined in the industrialized world as IBS onset following a sentinel gastrointestinal infection. In developing nations, where repeated bacterial and parasitic gastrointestinal infections are common, the IBS pathophysiology may be altered. Our aim was to investigate the relationship between intestinal parasite infection and IBS in the "nonsterile" developing world environment. IBS subjects were identified from a population-based sample of 1624 participants using the Rome II Modular Questionnaire. Stool samples from cases and randomly selected controls were examined for ova and parasites. Logistic regression models explored the relationship between IBS and parasite infection. The overall IBS prevalence among participants was 13.2% (9.3% males, 15.9% females). There was no difference in parasite carriage between IBS cases and controls, 16.6% versus 15.4% (P = 0.78), nor among IBS subtypes. The pathophysiology of post-infectious IBS may be altered in the developing world as compared to industrialized nations and warrants investigation.
RESUMO
The effects of N-methylation and chain length on a cation-pi interaction have been investigated within the context of a beta-hairpin peptide. Significant enhancement of the interaction and structural stabilization of the hairpin have been observed upon Lys methylation. Thermodynamic analysis indicates an increased entropic driving force for folding upon methylation of Lys residues. Comparison of lysine to analogues ornithine (Orn) and diaminobutyric acid (Dab) indicates that lysine provides the strongest cation-pi interaction and also provides the most stable beta-hairpin due to a combination of side chain-side chain interactions and beta-sheet propensities. These studies have significance for the recognition of methylated lysine in histone proteins.
