576 research outputs found
Analysis of ischaemic crisis using the informational causal entropy-complexity plane
In the present work, an ischaemic process, mainly focused on the reperfusion stage, is studied using the informational causal entropy-complexity plane. Ischaemic wall behavior under this condition was analyzed through wall thickness and ventricular pressure variations, acquired during an obstructive flow maneuver performed on left coronary arteries of surgically instrumented animals. Basically, the induction of ischaemia depends on the temporary occlusion of left circumflex coronary artery (which supplies blood to the posterior left ventricular wall) that lasts for a few seconds. Normal perfusion of the wall was then reestablished while the anterior ventricular wall remained adequately perfused during the entire maneuver. The obtained results showed that system dynamics could be effectively described by entropy-complexity loops, in both abnormally and well perfused walls. These results could contribute to making an objective indicator of the recovery heart tissues after an ischaemic process, in a way to quantify the restoration of myocardial behavior after the supply of oxygen to the ventricular wall was suppressed for a brief period.Fil: Legnani, Walter. Universidad TecnolĂłgica Nacional. Facultad Regional Buenos Aires; Argentina. Universidad Nacional de LanĂşs; ArgentinaFil: Traversaro Varela, Francisco. Instituto TecnolĂłgico de Buenos Aires; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Redelico, Francisco Oscar. Hospital Italiano; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad Nacional de Quilmes; ArgentinaFil: Cymberknop, Leandro Javier. Instituto Tecnologico de Buenos Aires. Departamento de Bioingenieria; Argentina. Universidad TecnolĂłgica Nacional. Facultad Regional Buenos Aires; ArgentinaFil: Armentano, Ricardo Luis. Universidad TecnolĂłgica Nacional. Facultad Regional Buenos Aires; Argentina. Instituto Tecnologico de Buenos Aires. Departamento de Bioingenieria; ArgentinaFil: Rosso, Osvaldo AnĂbal. Universidad de los Andes; Chile. Universidade Federal de Alagoas; Brasil. Hospital Italiano; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentin
Short-term assessment of left ventricular function after coronary artery bypass grafting
Background: The effect of coronary artery bypass grafting on postoperative left ventricular function is still the subject of ongoing studies. The degree of recovery and its duration have not been precisely determined, and the published data are discordant. The objective of this study was to assess the effect of surgical revascularization on left ventricular systolic function.
Methods: We prospectively studied 50 consecutive patients who underwent elective isolated coronary artery bypass grafting in the period from January 2017 to November 2017. All patients had echocardiography preoperatively, pre-discharge, and at 3 and 6 months postoperatively. Left ventricular end-systolic volume, left ventricular end-diastolic volume, stroke volume, and ejection fraction were measured in all patients.
Results: The mean age was 57.22±7.04 years. The mean number of grafts was 2.60±1.02. Improvement in Canadian Cardiovascular Society (CCS) score from (2.72 ± 1.03) preoperatively to [(0.12 ± 0.39), p<0.001] after six months was achieved. Additionally, improvement in the patient New York Heart Association (NYHA) score occurred from (1.70 ± 0.97) preoperatively to [(0.12 ± 0.33), p<0.001] after six months. A significant improvement in left ventricular function occurred as demonstrated by improvement in mean left ventricular ejection fraction from (54.14±9.80) % to [(62.40 ± 4.18) %, p<0.001] at six months. The mean total hospital stay was 5.62±1.51 days. The mean total intensive care unit length of stay was 47.16±25.73 hours. Two patients (4%) had re-exploration for bleeding, and postoperative myocardial infarction occurred in three patients (6%). One patient (2%) had postoperative neurocognitive dysfunction, and 3 patients (6%) had postoperative atrial fibrillation. Two patients (4%) suffered from superficial wound infection. There was no hospital mortality.
Conclusion: Patients undergoing CABG experienced an improvement in left ventricular contractile function at six months postoperatively. Further studies are required to evaluate the changes after 6 months
The effect of nitro-oleic versus losartan in diabetic nephropathy: modulation of parathyroid hormone-related protein
Background: Parathyroid hormone-related protein (PTHrP) involvement in the mechanisms related to angiotensin II (AngII)-induced renal injury has become an emerging concern. The current study was thus designed to compare the possible preventive and therapeutic effect of AngII antagonists, losartan and nitro-oleic (NO2-OA) acid, on diabetic nephropathy (DN) and evaluate their effect on PTHrP modulation as well as on the functional and histopathological parameters in the kidney of diabetic rats.Â
Materials and methods: Forty eight adult male Sprague Dawley rats were divided into control group, DN group, pre-diabetic nephropathy (pre-DN) losartan group, pre-diabetic nephropathy nitro-oleic acid (pre-DN NO2-OA) group, post-diabetic nephropathy (post-DN) losartan and post-diabetic nephropathy nitro-oleic acid (post-DN NO2-OA) groups. At the end of the study, systolic blood pressure (SBP), serum fasting glucose, glomerular filtration rate (GFR), urea, urea albumin excretion (UAE), serum angiotensin, renal PTHrP gene expression and correlations between PTHrP and SBP, serum glucose, AngII and kidney functions were evaluated. Histo- logical examination, Masson’s trichrome, periodic acid-Schiff staining as well as morphometric analysis and histopathological scoring for tubular and glomerular parameters have been carried out.Â
Results: Prophylactic losartan and NO2-OA were associated with improvement in SBP, serum glucose, urea, GFR, UAE, with reduction in serum AngII and PTHrP overexpression observed in diabetic kidney. Treatment with losartan and NO2-OA showed the same effect except that post-DN NO2-OA showed no significant effect regarding kidney function. Strong correlations were observed between PTHrP and SBP, serum glucose, AngII and kidney functions. Histopathological results revealed obvious improvement in glomerulosclerosis, vascular and tubular injury parameters in prophylactic groups especially with losartan.Â
Conclusions: Both pre and post-DN losartan, NO2-OA may have a potential role in protection and regression of DN through reduction of PTHrP overexpression.
Therapeutic role of bone marrow mesenchymal stem cells in diabetic neuronal alternations of rat hippocampus
Background: As the hippocampus is the main brain region for many forms of learning and memory functions and is acutely sensitive to blood glucose changes, diabetes mellitus, which is a serious metabolic disease, is often accompanied by learning and memory deficits. Through scientific literatures, mesenchymal stem cells (MSCs) promote functional recovery in rats with traumatic brain injury, so the present work was conducted to study MSCs as a possible treatment for the diabetic neuronal degeneration and functional impairment of rat hippocampus.
Materials and methods: It was carried out using male albino rats: non-diabetic control groups (4, 8, 12 weeks) (n = 15), diabetic groups by i.v. injection of streptozotocin for (4, 8, 12 weeks) (n = 15) and MSCs treatment to diabetic groups for (8, 12 weeks) (n = 10). Hippocampal learning and memory functions were assessed by the Morris Water Maze test and its results were statistically analysed. The rat hippocampal regions (CA1 and CA3) were subjected to histological, ultrastructural examination and morphometrical analyse of pyramidal neurons.
Results: Neurons of the diabetic groups showed disturbed function and architecture; shrunken hyperchromatic nuclei and vacuolated eosinophilic cytoplasm (apoptotic changes) also MSCs treatment improved hippocampal learning and memory functions plus its architectural changes; increasing populations and normal regular distribution.
Conclusions: It can be concluded that diabetic hippocampal neuronal alternations and functional impairment can be ameliorated by MSCs treatment
Experimental Indicators of Accretion Processes in Active Galactic Nuclei
Bright Active Galactic Nuclei are powered by accretion of mass onto the super
massive black holes at the centers of the host galaxies. For fainter objects
star formation may significantly contribute to the luminosity. We summarize
experimental indicators of the accretion processes in Active Galactic Nuclei
(AGN), i.e., observable activity indicators that allow us to conclude on the
nature of accretion. The Galactic Center is the closest galactic nucleus that
can be studied with unprecedented angular resolution and sensitivity.
Therefore, here we also include the presentation of recent observational
results on Sagittarius A* and the conditions for star formation in the central
stellar cluster. We cover results across the electromagnetic spectrum and find
that the Sagittarius A* (SgrA*) system is well ordered with respect to its
geometrical orientation and its emission processes of which we assume to
reflect the accretion process onto the super massive black hole.Comment: 16 pages, 4 figures, conference proceeding: Accretion Processes in
Cosmic Sources - APCS2016 - 5-10 September 2016, Saint Petersburg, Russi
Heme oxygenase effect on mesenchymal stem cells action on experimental Alzheimer's disease
The objective is to evaluate the effect of heme oxygenase-1 (HO-1) enzyme inducer and inhibitor on Mesenchymal Stem Cells (MSCs) in Alzheimer disease. Materials and Methods: 70 female albino rats were divided equally into 7 groups as follows:
group 1: healthy control; group 2: Aluminium chloride induced Alzheimer disease; group 3:
induced Alzheimer rats that received intravenous injection of MSCs; group 4: induced Alzheimer rats that received MSCs and HO inducer cobalt protoporphyrin; group 5: induced Alzheimer rats that received MSCs and HO inhibitor zinc protoporphyrin; group 6: induced Alzheimer rats that received HO inducer; group7: induced Alzheimer rats that received HO inhibitor. Brain tissue was collected for HO-1, seladin-1 gene expression by real time polymerase chain reaction, heme oxygenase activity, cholesterol estimation and histopathological examination. Results: MSCs decreased the plaque lesions, heme oxygenase induction with stem cells also decreased plaque lesions however there was hemorrhage in the brain. Both heme oxygenase inducer alone or with stem cells increased seladin-1 expression and decreased cholesterol level.
Conclusion: MSCs alone or with HO-1 induction
exert a therapeutic effect against the brain
lesion in Alzheimer’s disease possibly through decreasing the brain cholesterol level and increasing seladin-1 gene expression
CFD Investigation on the Steady Interaction between an Offset Jet and an Oblique Wall Jet
In this paper a CFD investigation on the interaction between an offset jet and an oblique wall jet using two-dimensional steady RANS equations is performed. This combination is denoted WOJ (Wall Offset jets). Several turbulence models such as the standard k-ω, SST k-ω, standard k-ε, RNG k-ε and realizable k-ε models are tested in the present study. A parametric study is performed to highlight the wall inclination effect on the WOJ flow maximum velocity decay as well as the shear layers spreading. Comparison between combined wall and offset jet (WOJ) and single offset jet (SOJ) flows is also established. Results show that increasing the wall inclination improves the combined wall and offset jets flow spreading. Furthermore, the outer shear layers spreading, is better than the inner shear layers one. Comparing to the combined wall and offset jet flow (WOJ), a better spreading is found in the case of single offset jet flow (SOJ)
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