The heat shock response of Arabidopsis thaliana is dependent upon a complex regulatory network involving twenty-one known transcription factors and four heat shock protein families. It is known that heat shock proteins (Hsps) and transcription factors (Hsfs) are involved in cellular response to various forms of stress besides heat. However, the role of Hsps and Hsfs under cold and non-thermal stress conditions is not well understood, and it is unclear which types of stress interact least and most strongly with Hsp and Hsf response pathways. To address this issue, we have analyzed transcriptional response profiles of Arabidopsis Hsfs and Hsps to a range of abiotic and biotic stress treatments (heat, cold, osmotic stress, salt, drought, genotoxic stress, ultraviolet light, oxidative stress, wounding, and pathogen infection) in both above and below-ground plant tissues.

Degenerative mitral regurgitation is common and can be surgically repaired in the vast majority of patients,^1,2 improving symptoms and restoring normal life expectancy.^3-6 Despite the safety and efficacy of contemporary surgical correction, an ongoing international debate persists regarding the need for early intervention^7-9 in patients without the American College of Cardiology (ACC)/American Heart Association (AHA) guideline class I triggers (no or minimal symptoms and absence of left ventricular dysfunction). This is in part propagated by discordant views of the prognostic consequences of uncorrected severe mitral regurgitation; considered as benign by those supporting medical watchful waiting¹⁰ (nonsurgical observation until a distinct event is encountered) vs conveying excess mortality and morbidity (including heart failure and atrial fibrillation) by those advocating early surgical intervention.^5,11 This controversy is reflected in current international consensus statements, in which North American documents categorize early mitral surgery as a class IIA recommendation (in favor of the procedure),¹² whereas it is a class IIB recommendation in Europe (not strongly in favor of the procedure).¹³

Background: Mitral valve (MV) repair is preferred over replacement in clinical guidelines and is an important determinant of the indication for surgery in degenerative mitral regurgitation. However, the level of evidence supporting current recommendations is low, and recent data cast doubts on its validity in the current era. Accordingly, the aim of the present study was to analyze very long-term outcome after MV repair and replacement for degenerative mitral regurgitation with a flail leaflet. Methods: MIDA (Mitral Regurgitation International Database) is a multicenter registry enrolling patients with degenerative mitral regurgitation with a flail leaflet in 6 tertiary European and US centers. We analyzed the outcome after MV repair (n=1709) and replacement (n=213) overall, by propensity score matching, and by inverse probability-of-treatment weighting. Results: At baseline, patients undergoing MV repair were younger, had more comorbidities, and were more likely to present with a posterior leaflet prolapse than those undergoing MV replacement. After propensity score matching and inverse probability-of-treatment weighting, the 2 treatments groups were balanced, and absolute standardized differences were usually <10%, indicating adequate match. Operative mortality (defined as a death occurring within 30 days from surgery or during the same hospitalization) was lower after MV repair than after replacement in both the entire population (1.3% versus 4.7%; P <0.001) and the propensity-matched population (0.2% versus 4.4%; P <0.001). During a mean follow-up of 9.2 years, 552 deaths were observed, of which 207 were of cardiovascular origin. Twenty-year survival was better after MV repair than after MV replacement in both the entire population (46% versus 23%; P <0.001) and the matched population (41% versus 24%; P <0.001). Similar superiority of MV repair was obtained in patient subsets on the basis of age, sex, or any stratification criteria (all P <0.001). MV repair was also associated with reduced incidence of reoperations and valve-related complications. Conclusions: Among patients with degenerative mitral regurgitation with a flail leaflet referred to mitral surgery, MV repair was associated with lower operative mortality, better long-term survival, and fewer valve-related complications compared with MV replacement.

To evaluate a mastery learning, simulation-based curriculum for laparoscopic, totally extraperitoneal (TEP) inguinal hernia repair. Clinically relevant benefits from improvements in operative performance, time, and errors after simulation-based training are not clearly established. After performing a baseline TEP in the OR, general surgery residents randomized to mastery learning (ML) or standard practice (SP) were reassessed during subsequent TEPs. The ML curriculum involved Web-based modules followed by training on a TEP simulator until expert performance was achieved. Operative time, performance, and patient outcomes adjusted for staff, resident participation, difficulty of repair, PGY-level, and patient comorbidities were compared between groups with mixed effects-ANOVA and generalized linear models. Fifty residents (PGY1-5) performed 219 TEP repairs on 146 patients. Baseline operative time, performance, and demographics were similar between groups. To achieve mastery, ML-residents (n = 26) required a median of 16 (range 7–27) simulated repairs. After training, TEPs performed by ML-residents were faster than those by SP-residents, with time corrected for participation (mean ± SD, 34 ± 8 minutes vs. 48 ± 14 minutes; difference –13; 95%CI, –18 to –8; P < 0.001). Operative performance scores (GOALS, scale 6–30) were better for ML residents (21.9 ± 2.8 vs. 18.3 ± 3.8; P = 0.001). Intraoperative complications (peritoneal tear, procedure conversion), postoperative complications (urinary retention, seroma), and need for overnight stay were less likely in the ML group (adjusted odds ratios 0.14, 0.04, and 0, respectively; all P < 0.05). A simulation-based ML curriculum decreased operative time, improved trainee performance, and decreased intra- and postoperative complications and overnight stays after laparoscopic TEP inguinal hernia repair. ClinicalTrials.gov Identifier: NCT01085500