This paper introduces a novel method for theoretical determination of amino acid substitution groups. The method here involves making a binary matrix based on 48 qualitative physicochemical properties and calculating a substitution matrix based on this using dot products. Isolated groups with high scores are determined to be valid substitution groups and conserved groups are derived from these valid groups. 258 valid groups and 31 conserved groups are found.

International audienceThe diagnosis of Marfan syndrome (MFS) is challenging and international criteria have been proposed. The 1996 Ghent criteria were adopted worldwide, but new diagnostic criteria for MFS were released in 2010, giving more weight to aortic root aneurysm and ectopia lentis. We aimed to compare the diagnosis reached by applying this new nosology vs the Ghent nosology in a well-known series of 1009 probands defined by the presence of an FBN1 mutation. A total of 842 patients could be classified as MFS according to the new nosology (83%) as compared to 894 (89%) according to the 1996 Ghent criteria. The remaining 17% would be classified as ectopia lentis syndrome (ELS), mitral valve prolapse syndrome or mitral valve, aorta, skeleton and skin (MASS) syndrome, or potential MFS in patients aged less than 20 years. Taking into account the median age at last follow-up (29 years), the possibility has to be considered that these patients would go on to develop classic MFS with time. Although the number of patients for a given diagnosis differed only slightly, the new nosology led to a different diagnosis in 15% of cases. Indeed, 10% of MFS patients were reclassified as ELS or MASS in the absence of aortic dilatation; conversely, 5% were reclassified as MFS in the presence of aortic dilatation. The nosology is easier to apply because the systemic score is helpful to reach the diagnosis of MFS only in a minority of patients. Diagnostic criteria should be a flexible and dynamic tool so that reclassification of patients with alternative diagnosis is possible, requiring regular clinical and aortic follow-up

Extubation of patients under ECLS is safe and feasible. Furthermore, in extubated patients, we observed fewer cases of ventilator-associated pneumonia and better 30-day survival rates.

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International audienceStudy Type - Therapy (case series) Level of Evidence 4 OBJECTIVE To review experience with nephrectomy/thrombectomy for a renal cell carcimoma (RCC) with a level IV tumour thrombus and to evaluate the benefit of deep hypothermic circulatory arrest (DHCA) with cardiopulmonary bypass (CPBP). PATIENTS AND METHODS A multi-institutional retrospective database was created to assess the outcomes of surgery for RCC and associated level IV tumour thrombus from 1983 to 2007. Patients were identified based on radiographic records/operative findings. Only cases using CPBP were analysed. Clinicopathological and operative characteristics including use of DHCA were recorded. Overall survival (OS) for all patients and by use of DHCA was assessed. Comparisons of clinical and operative characteristics by use of DHCA were performed. A Cox regression model determined predictors of perioperative/in-hospital mortality. RESULTS In all, 63 patients underwent resection with CPBP; overall perioperative mortality was 22.2%. There were no significant differences in clinicopathological characteristics, operative duration, estimated blood loss, transfusions, and hospital stay by use of DHCA. Perioperative mortality rate was lower in patients undergoing DHCA (8.3% vs 37.5%, P= 0.006). The median OS was longer for the patients undergoing DHCA (15.8 vs 7.7 months); however, this failed to reach statistical significance (P= 0.357). On multivariate analysis, age of >60 years (hazard ratio [HR] 6.7, 95% confidence interval [CI] 1.5-31.1, P= 0.015) and the use of DHCA (HR 0.13, 95% CI 0.036-0.51, P= 0.003) were independent predictors of perioperative mortality. CONCLUSIONS Radical nephrectomy and level IV tumour thrombectomy is associated with significant mortality. The use of DHCA does not appear to adversely affect operative characteristics and may limit perioperative mortality. Further prospective studies should be performed to confirm the benefit of DHCA