Does myocardial protection by isoflurane preconditioning preserve Ca2+ cycling proteins independent of sarcolemmal and mitochondrial KATP channels?
I/R-induced depression in cardiac performance is associated with a down-regulation of the major sarcoplasmic reticulum Ca2+-cycling proteins. Anesthesia preconditioning with isoflurane prevents I/R-related degradation of the RyR2 and SERCA2a in the sarcoplasmic reticulum. However, this effect was independent of its activation of K(ATP) channels.
Increased apoptosis in reflux esophagitis may be a protective mechanism counteracting increased proliferation. Inhibition of apoptosis by overexpression of bcl-2 protein occurs early in the dysplasia-carcinoma sequence of Barrett esophagus. The resulting prolongation of cell survival may promote neoplastic progression. Despite the absence of apoptosis, bcl-2 was not widely overexpressed in Barrett high-grade dysplasia and adenocarcinoma, suggesting that cells acquire other ways of avoiding apoptosis as malignancy appears.