Impairment of agonist-induced M muscarinic receptor activation by autoantibodies from chagasic patients with cardiovascular dysautonomia.

Previous studies showed that circulating autoantibodies against M muscarinic receptors (anti-MR Ab) are associated with decreased cardiac parasympathetic modulation in patients with chronic Chagas disease (CD). Here we investigated whether the exposure of MR to such antibodies could impair agonist-induced receptor activation, leading to the inhibition of associated signaling pathways. Preincubation of MR-expressing HEK 293T cells with serum IgG fractions from chagasic patients with cardiovascular dysautonomia, followed by the addition of carbachol, resulted in the attenuation of agonist-induced G protein activation and arrestin-2 recruitment.

Molecular characterization of ESBL-producing Shigella sonnei isolates from patients with bacilliary dysentery in Lebanon.

Background: Emergence of extended-spectrum beta-lactamases (ESBLs) in Shigella species imparting resistance to third-generation cephalosporins is a growing concern worldwide. The aim of this study is to molecularly characterize the newly emerging beta-lactam resistant Shigella sonnei, specifically ESBLs in Lebanon, and compare them to beta-lactam sensitive isolates.

Methodology: We compared five beta-lactam-resistant S.