Advanced echocardiography in characterization and management of patients with secondary mitral regurgitation

Severe secondary MR is known to be associated with a worse prognosis, whilst the effect of reducing MR on prognosis has still been unclear. The question remains what influences the prognosis of these patients: is it the LV or the valve (i.e. the MR)? Characterization and risk-stratification of patients with secondary MR therefore remains challenging. Until recently the decision to intervene for secondary MR was based also on the LVEF. However, LVEF is subject to many limitations. Advanced echocardiography, such as speckle tracking echocardiography, from which LVGLS could be derived has shown to be of much more diagnostic and prognostic value in various valvular heart disease and is currently being implemented more in valvular heart disease guidelines. This supports the fact that LVGLS can detect LV dysfunction in an earlier stage and therefore guide physicians to refer patients for intervention before it is too late. Also the mitral valve geometry has an important role in the technical feasibility of intervention, but also could elaborate on which specific transcatheter intervention is more appropriate according to their targets (i.e. leaflets, annulus or sub apparatus). Additionally, multimodality imaging remains key in characterization and quantification of secondary MR and may help further risk-stratification.LUMC / Geneeskund

Applying a novel combination of techniques to develop a predictive model for diabetes complications

© 2015 Sangi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Among the many related issues of diabetes management, its complications constitute the main part of the heavy burden of this disease. The aim of this paper is to develop a risk advisor model to predict the chances of diabetes complications according to the changes in risk factors. As the starting point, an inclusive list of (k) diabetes complications and (n) their correlated predisposing factors are derived from the existing endocrinology text books. A type of data meta-analysis has been done to extract and combine the numeric value of the relationships between these two. The whole n (risk factors) - k (complications) model was broken down into k different (n-1) relationships and these (n-1) dependencies were broken into n (1-1) models. Applying regression analysis (seven patterns) and artificial neural networks (ANN), we created models to show the (1-1) correspondence between factors and complications. Then all 1-1 models related to an individual complication were integrated using the naïve Bayes theorem. Finally, a Bayesian belief network was developed to show the influence of all risk factors and complications on each other. We assessed the predictive power of the 1-1 models by R2, F-ratio and adjusted R2 equations; sensitivity, specificity and positive predictive value were calculated to evaluate the final model using real patient data. The results suggest that the best fitted regression models outperform the predictive ability of an ANN model, as well as six other regression patterns for all 1-1 models

Individually addressable double quantum dots formed with nanowire polytypes and identified by epitaxial markers

Double quantum dots (DQDs) hold great promise as building blocks for quantum technology as they allow for two electronic states to coherently couple. Defining QDs with materials rather than using electrostatic gating allows for QDs with a hard-wall confinement potential and more robust charge and spin states. An unresolved problem is how to individually address these quantum dots, which is necessary for controlling quantum states. We here report the fabrication of double quantum dot devices defined by the conduction band edge offset at the interface of the wurtzite and zinc blende crystal phases of InAs in nanowires. By using sacrifical epitaxial GaSb markers selectively forming on one crystal phase, we are able to precisely align gate electrodes allowing us to probe and control each QD independently. We hence observe textbook-like charge stability diagrams, a discrete energy spectrum and electron numbers consistent with theoretical estimates and investigate the tunability of the devices, finding that changing the electron number can be used to tune the tunnel barrier as expected by simple band diagram arguments.Comment: 5 pages, 3 figure

Cytochrome-P450 enzymes and autoimmunity: expansion of the relationship and introduction of free radicals as the link

The Cytochrome-P-450 enzymes (CYP) are among the most important xenobiotic-metabolizing enzymes, which produce reactive oxygen species (ROS) as the result of metabolizing xenobiotics

Sex differences in prognosis of significant secondary mitral regurgitation

Aims Secondary mitral regurgitation (MR) is more frequent in men than in women. However, little is known about differences in prognosis between men and women with secondary MR. The objective of this study is to investigate the sex distribution of secondary MR and the prognostic differences between sexes.Methods Patients with significant secondary MR, of both ischaemic and non-ischaemic aetiologies, were identified through the departmental electronic patient files and retrospectively analysed. The primary endpoint was all-cause mortality.Results A total of 698 patients (mean age 66 +/- 11 years) with significant secondary MR were included: 471 (67%) men and 227 (33%) women. Ischaemic heart failure was significantly more common in men (61%), whereas non-ischaemic heart failure was more prevalent in women (63%). Women had significantly smaller left ventricular (LV) volumes when compared with men and more preserved LV systolic function when assessed with LV global longitudinal strain (GLS; 8.5 +/- 4.1% vs. 7.5 +/- 3.6%; P = 0.004). Women more often underwent surgical mitral valve repair (34%) when compared with men (26%), although no differences were observed for transcatheter mitral valve repair. During a median follow-up of 57 [interquartile range 29-110] months, 373 (53%) patients died. Women showed significantly lower mortality rates at 1-, 2- and 5-year follow-up (9%, 16% and 33% vs. 10%, 20% and 42%) when compared with men (P = 0.001).Conclusions Significant secondary MR is more frequently observed in men as compared with women and is associated with worse prognosis.Cardiolog

Prognostic implications of left ventricular myocardial work indices in patients with secondary mitral regurgitation

Background: Assessment of left ventricular (LV) function in patients with secondary mitral regurgitation (SMR) remains challenging but is an important parameter for risk stratification. The association of LV myocardial work components (work index [GWI], constructive [GCW] and wasted [GWW] work, and work efficiency) derived from pressure-strain loops obtained with speckle tracking echocardiography, and all-cause mortality in patients with SMR was investigated. Methods: LV myocardial GWI, GCW, GWW, and global work efficiency were measured with speckle tracking strain echocardiography in 373 patients (72% men, median age 68 years) with various grades of SMR. All-cause mortality was the primary end point. Results: Mild SMR was observed in 143 patients, 128 had moderate SMR, and 102 had severe SMR. Patients with severe SMR had the largest LV volumes and the worst LV ejection fraction and LV global longitudinal strain. In patients with severe SMR, LV GWI and GCW were more impaired (500 mm Hg% versus 680 mm Hg% P=0.024 and 678 mm Hg% versus 851 mm Hg% P=0.006, respectively), while GWW was lower (130 mm Hg% versus 260 mm Hg% P<0.001, respectively) and global work efficiency was significantly higher (82% versus 76%, P=0.001) compared with patients with mild SMR. After a median follow-up of 56 months, 161 patients died. LV GWI <= 500 mm Hg%, LV GCW <= 750 mm Hg%, and LV GWW Conclusions: Patients with severe SMR had the worst LV GWI and LV GCW but better LV GWW and global work efficiency reflecting the unloading of the LV in the low-pressure left atrial chamber. These parameters were independently associated with worse long-term survival in patients with SMR.Cardiolog

Taxifolin prevents cisplatin nephrotoxicity by modulating Nrf2/HO-1 pathway and mitigating oxidative stress and inflammation in mice

Cisplatin (CIS) is an effective chemotherapeutic agent used in the treatment of several malignancies. The clinical use of CIS is associated with adverse effects, including acute kidney injury (AKI). Oxidative stress and inflammation are key events in the development of CIS-induced AKI. This study investigated the protective effect of taxifolin (TAX), a bioactive flavonoid with promising health-promoting properties, on CIS-induced nephrotoxicity in mice. TAX was orally given to mice for 10 days and a single dose of CIS was injected at day 7. Serum blood urea nitrogen (BUN) and creatinine were elevated, and multiple histopathological alterations were observed in the kidney of CIS-administered mice. CIS increased renal malondialdehyde (MDA), nitric oxide (NO), nuclear factor-kappaB (NF-κB) p65, tumor necrosis factor (TNF)-α, and interleukin (IL)-1β, and decreased cellular antioxidants in mice. TAX remarkably prevented kidney injury, ameliorated serum BUN and creatinine, and renal MDA, NO, NF-κB p65, and pro-inflammatory cytokines, and boosted antioxidant defenses in CIS-administered mice. TAX downregulated Bax and caspase-3, and upregulated Bcl-2. These effects were associated with upregulation of nuclear factor erythroid 2-related factor 2 (Nrf2) expression and heme oxygenase (HO)-1 activity in CIS-administered mice. In conclusion, TAX prevented CIS-induced AKI by mitigating tissue injury, oxidative stress, inflammation, and cell death. The protective efficacy of TAX was associated with the upregulation of Nrf2/HO-1 signaling

Human factors for dementia: Evidence based design

Designing care environments for people living with dementia is a complex challenge as the key stakeholder may have difficulty communicating their capabilities, limitations and preferences. This paper describes the use of evidence-based design personas in a multi-disciplinary team with architects and chartered human factors specialists. Four individual personas (Alison, Barry, Christine and David) and a couple persona (Chris and Sally) were used to bring the voices of the people living with different stages of dementia to the design process. Their changing/fluctuating symptoms were communicated in two formats (wheel and matrix) within an inclusive design process to adapt a Victorian semi-detached house. The demonstrator house presents evidence based design, adaptation and support solutions to support people living with dementia to age well at home

Comparison of the h-index for different fields of research using bootstrap methodology

An important disadvantage of the h-index is that typically it cannot take into account the specific field of research of a researcher. Usually sample point estimates of the average and median h-index values for the various fields are reported that are highly variable and dependent of the specific samples and it would be useful to provide confidence intervals of prediction accuracy. In this paper we apply the non-parametric bootstrap technique for constructing confidence intervals for the h-index for different fields of research. In this way no specific assumptions about the distribution of the empirical h-index are required as well as no large samples since that the methodology is based on resampling from the initial sample. The results of the analysis showed important differences between the various fields. The performance of the bootstrap intervals for the mean and median h-index for most fields seems to be rather satisfactory as revealed by the performed simulation