Non-uniform recovery of left ventricular transmural mechanics in ST-segment elevation myocardial infarction

<p>Abstract</p> <p>Background</p> <p>After a transient ischemic episode, the subendocardial region is more severely injured than outer subepicardial layers and may regain a proportionately greater degree of mechanical function in the longitudinal direction. We sought to explore left ventricular (LV) transmural mechanics in patients with ST-segment elevation myocardial infarction (STEMI) for determining the mechanism underlying recovery of global LV function after primary percutaneous coronary intervention (PCI).</p> <p>Methods</p> <p>A total of 42 patients (62 ± 11 years old, 71% male) with a first STEMI underwent serial assessments of LV longitudinal, circumferential and radial strains (LS, CS and RS) by selective tracking of subendocardial and subepicardial regions within 48 hours and a median of 5 months after PCI. LV mechanical parameters were compared with sixteen age and gender matched normal controls.</p> <p>Results</p> <p>In comparison with controls, endocardial and epicardial LS were markedly attenuated at 48 hours following PCI (P < 0.001). An improvement in LV ejection fraction (EF > 5%) following PCI was seen in 24 (57%) patients and was associated with improvement in endocardial and epicardial LS (P < 0.001 and P = 0.003, respectively) and endocardial CS (P = 0.01). Radial strain and wall motion score index, however, remained persistently abnormal. The change in endocardial LS (OR 1.2, 95% CI 1.03 to 1.42, P = 0.01) and the change in epicardial LS (OR 1.2, 95% 1.03 to 1.46, P = 0.02) were significantly associated with the improvement in LVEF, independent of the location of STEMI and the presence of underlying multivessel disease.</p> <p>Conclusions</p> <p>In patients with STEMI treated by PCI, the recovery of LV subendocardial shortening strain seen in the longitudinal direction underlies the improvement in LV global function despite persistent abnormalities in radial mechanics and wall motion score index.</p

The Role of the Frank–Starling Law in the Transduction of Cellular Work to Whole Organ Pump Function: A Computational Modeling Analysis

We have developed a multi-scale biophysical electromechanics model of the rat left ventricle at room temperature. This model has been applied to investigate the relative roles of cellular scale length dependent regulators of tension generation on the transduction of work from the cell to whole organ pump function. Specifically, the role of the length dependent Ca2+ sensitivity of tension (Ca50), filament overlap tension dependence, velocity dependence of tension, and tension dependent binding of Ca2+ to Troponin C on metrics of efficient transduction of work and stress and strain homogeneity were predicted by performing simulations in the absence of each of these feedback mechanisms. The length dependent Ca50 and the filament overlap, which make up the Frank-Starling Law, were found to be the two dominant regulators of the efficient transduction of work. Analyzing the fiber velocity field in the absence of the Frank-Starling mechanisms showed that the decreased efficiency in the transduction of work in the absence of filament overlap effects was caused by increased post systolic shortening, whereas the decreased efficiency in the absence of length dependent Ca50 was caused by an inversion in the regional distribution of strain

Environmental Impact Assessment (EIA) and Optimal Site Selection of Municipal Solid Waste Landfill via SAW, GIS and Leopold Matrix (Case Study: Yazd)

Introduction: Waste production from any source would lead to the formation of various pollutants. The existence of these materials and in turn, every non-normative plan designed for waste disposal produces environmentally detrimental effects. Therefore, evaluating positive and negative effects of influential engineering- sanitary projects in environment seem to be necessary such as landfill construction for management of urban health. The present study aimed to evaluate positioning and of municipal solid waste landfills by geological information system (GIS). To this purpose, the required layers were prepared and profit sites were obtained by 3 steps: talent mapping, field survey to study characteristics of suitable areas and EIA by means of Leopold matrix for zonal ranking and selection of optimal location. Results: To depict talent map, the layers were combined by simple additive weighting method using various data including geology, land use, distance from the city boundaries, slope, distance from roads, vegetation, infiltration and hydrology. The resulted data suggested that four sites were posited in appropriate ranks. Conclusion: The study findings revealed, that site No.1 (X:256915 & Y:3540127) was determined as the optimum location for engineering - Sanitary landfill

Glycosylphosphatidylinositols synthesized by Trichophyton rubrum in a cell-free system. Nachweis von Glykosylphosphatidylinositolen von Trichophyton rubrum synthetisiert im zellfreien System

Pusch U, Effendy I, Schwarz RT, Azzouz N. Glycosylphosphatidylinositols synthesized by Trichophyton rubrum in a cell-free system. Mycoses. 2003;46(3-4):104-113.The opportunistic fungi Trichophyton rubrum and T. mentagrophytes , are responsible for relatively non-inflammatory chronic dermatophytes infections in immunocompromised patients but also in healthy individuals. This chronic infection is associated with immunosuppressive effects of the cell wall components particularly the polysaccharides secreted by these organisms. We have studied glycosylphosphatidylinositol (GPI) anchor biosynthesis in the pathogenic fungus T. rubrum and could demonstrate that T. rubrum is able to synthesize GPI structures. Glycolipids synthesized in a cell-free system prepared from the dermatophyte T. rubrum and labeled with [(3) H]mannose, and [(3) H]galactose using GDP-[(3) H]mannose and UDP-[(3) H]galactose, respectively, were identified and structurally characterized as GPIs. The evolutionary conserved backbone of T. rubrum GPIs incorporates galactose. Further, all glycolipids lack the acyl group on the inositol which was shown for Saccharomyces cerevisiae and mammalian GPIs. Our data suggest significant differences in the GPI biosynthetic pathway between mammalian and T. rubrum cells that could perhaps be exploited for the development of an antimycotic for Trichophyton infection