Calmodulin is a nonessential activator of secretory phospholipase A(2)

Ammodytoxins are presynaptically neurotoxic snake venom group IIA secreted phospholipase A(2) enzymes that interact specifically with calmodulin in the cytosol of nerve cells. We show that calmodulin behaves as an activator of ammodytoxin under both nonreducing and reducing (cytosol-like) conditions by stimulating its enzymatic activity up to 21-fold. Kinetic analysis, using a general modifier mechanism, and surface plasmon resonance measurements reveal that calmodulin influences both the catalytic and the vesicle binding properties of the enzyme without affecting its calcium binding properties. The equilibrium dissociation constant of the ammodytoxin-calmodulin complex under cytosol-like conditions is in the low nanomolar range (3 nM), while under nonreducing conditions, the binding affinity is in the subnanomolar range (0.07-0.18 nM). Upon exposure to cytosol-like conditions, ammodytoxin undergoes a slow hysteretic transition to a less active state. Calmodulin stabilizes the conformation of ammodytoxin and thereby restores its activity. These results provide insights into the neurotoxic action of ammodytoxins and the mechanisms involved in the regulation of secreted phospholipase A(2) activity within the cytosol

Mortality after surgery in Europe: a 7 day cohort study

Background: Clinical outcomes after major surgery are poorly described at the national level. Evidence of heterogeneity between hospitals and health-care systems suggests potential to improve care for patients but this potential remains unconfirmed. The European Surgical Outcomes Study was an international study designed to assess outcomes after non-cardiac surgery in Europe.Methods: We did this 7 day cohort study between April 4 and April 11, 2011. We collected data describing consecutive patients aged 16 years and older undergoing inpatient non-cardiac surgery in 498 hospitals across 28 European nations. Patients were followed up for a maximum of 60 days. The primary endpoint was in-hospital mortality. Secondary outcome measures were duration of hospital stay and admission to critical care. We used χ² and Fisher’s exact tests to compare categorical variables and the t test or the Mann-Whitney U test to compare continuous variables. Significance was set at p<0·05. We constructed multilevel logistic regression models to adjust for the differences in mortality rates between countries.Findings: We included 46 539 patients, of whom 1855 (4%) died before hospital discharge. 3599 (8%) patients were admitted to critical care after surgery with a median length of stay of 1·2 days (IQR 0·9–3·6). 1358 (73%) patients who died were not admitted to critical care at any stage after surgery. Crude mortality rates varied widely between countries (from 1·2% [95% CI 0·0–3·0] for Iceland to 21·5% [16·9–26·2] for Latvia). After adjustment for confounding variables, important differences remained between countries when compared with the UK, the country with the largest dataset (OR range from 0·44 [95% CI 0·19 1·05; p=0·06] for Finland to 6·92 [2·37–20·27; p=0·0004] for Poland).Interpretation: The mortality rate for patients undergoing inpatient non-cardiac surgery was higher than anticipated. Variations in mortality between countries suggest the need for national and international strategies to improve care for this group of patients.Funding: European Society of Intensive Care Medicine, European Society of Anaesthesiology