Association between Helicobacter pylori Infection and Nasal Polyps: A Systematic Review and Meta-Analysis.

BACKGROUND Helicobacter pylori (H. pylori) has definite or possible associations with multiple local and distant manifestations. H. pylori has been isolated from multiple sites throughout the body, including the nose. Clinical non-randomized studies with H. pylori report discrepant data regarding the association between H. pylori infection and nasal polyps. The aim of this first systematic review and meta-analysis was the assessment of the strength of the association between H. pylori infection and incidence of nasal polyps. METHODS We performed an electronic search in the three major medical databases, namely PubMed, EMBASE and Cochrane, to extract and analyze data as per PRISMA guidelines. RESULTS Out of 57 articles, 12 studies were graded as good quality for analysis. Male-to-female ratio was 2:1, and age ranged between 17-78 years. The cumulative pooled rate of H. pylori infection in the nasal polyp group was 32.3% (controls 17.8%). The comparison between the two groups revealed a more significant incidence of H. pylori infection among the nasal polyp group (OR 4.12), though with high heterogeneity I$^{2}$ = 66%. Subgroup analysis demonstrated that in European studies, the prevalence of H. pylori infection among the nasal polyp group was significantly higher than in controls, yielding null heterogeneity. Subgroup analysis based on immunohistochemistry resulted in null heterogeneity with preserving a statistically significant difference in H. pylori infection prevalence between the groups. CONCLUSION The present study revealed a positive association between H. pylori infection and nasal polyps

Activation and Deactivation of a Robust Immobilized Cp*Ir-Transfer Hydrogenation Catalyst: A Multielement in Situ X-ray Absorption Spectroscopy Study

A highly robust immobilized [Cp*IrCl2]2 precatalyst on Wang resin for transfer hydrogenation, which can be recycled up to 30 times, was studied using a novel combination of X-ray absorption spectroscopy (XAS) at Ir L3-edge, Cl K-edge, and K K-edge. These culminate in in situ XAS experiments that link structural changes of the Ir complex with its catalytic activity and its deactivation. Mercury poisoning and “hot filtration” experiments ruled out leached Ir as the active catalyst. Spectroscopic evidence indicates the exchange of one chloride ligand with an alkoxide to generate the active precatalyst. The exchange of the second chloride ligand, however, leads to a potassium alkoxide–iridate species as the deactivated form of this immobilized catalyst. These findings could be widely applicable to the many homogeneous transfer hydrogenation catalysts with Cp*IrCl substructure