INFLUENCE OF PULSATILE CATHETER PUMP SYNCHRONIZATION ON HAEMODYNAMIC VARIABLES: NUMERICAL SIMULATION

Severe cardiovascular diseases can be treated using left ventricular assist devices (LVAD). One of the possible LVADs is the Pulsatile Catheter (PUCA) pump that consists of a hydraulically or pneumatically driven membrane pump connected to a valved catheter. In this work a numerical model of the cardiocirculatory system and of the PUCA have been developed in order to study their interaction. In the numerical simulator a pathological condition of the left ventricle has been reproduced and successively the effects of the PUCA on the haemodynamic variables applied were studied. Different functioning modes were tested by changing the ratio between the pump frequency and the heart beat rate (HR) as 1:1, 1:2 or 1:3 and by introducing a delay time between the cardiac and the PUCA cycle. The performance of the pump was evaluated in terms of cardiac output, PUCA and coronary flows and it was studied for different HR values. Results show a good resemblance between the model and literature data and indicate that different synchronization and timing can influence the functioning of the pump. In particular, the frequency ratio and the time delay of the pump cycle can contribute to optimize the performance of the PUCA

Influence of Pulsatile Catheter Pump Synchronization on Haemodynamic Variables: Numerical Simulation.

Severe cardiovascular diseases can be treated using left ventricular assist devices (LVAD). One of the possible LVADs is the Pulsatile Catheter (PUCA) pump that consists of a hydraulically or pneumatically driven membrane pump connected to a valved catheter. In this work a numerical model of the cardiocirculatory system and of the PUCA have been developed in order to study their interaction. In the numerical simulator a pathological condition of the left ventricle has been reproduced and successively the effects of the PUCA on the haemodynamic variables applied were studied. Different functioning modes were tested by changing the ratio between the pump frequency and the heart beat rate (HR) as 1:1, 1:2 or 1:3 and by introducing a delay time between the cardiac and the PUCA cycle. The performance of the pump was evaluated in terms of cardiac output, PUCA and coronary flows and it was studied for different HR values. Results show a good resemblance between the model and literature data and indicate that different synchronization and timing can influence the functioning of the pump. In particular, the frequency ratio and the time delay of the pump cycle can contribute to optimize the performance of the PUCA

Assessment of telomere length during post-natal period in offspring produced by a bull and its fibroblast derived clone

Objective: To investigate the telomere length in bovine offspring produced by a cloned and control bull, and the telomerase activity in embryos produced with the same technology. Methods: Five daughters of a control and five daughters of a bull cloned using a fibroblast of the control were produced by IVF using sperm of the two bulls. Blood samples of the offspring were collected at 2, 6, and 12 months of age and the relative telomere length (RTL) was assessed by flow cytometry. At same time the body growth, hematological profile, and clinical biochemistry of the same progeny was extensively surveyed, and results have been reported in a previous work. Thereafter, the telomerase activity was assessed using a real time PCR quantitative assay in groups of embryos produced with the same technology. Results: The offspring of the clone exhibited a modest, but significant (P<0.05), shortening of the telomeres (21.36%, 20.56% and 20.56%) compared to that of the control (23.78%, 23.53% and 22.43%) as mean values determined at 2, 6 and 12 months, respectively. Shortening of telomeres in respect to the age was not significant. No statistical difference was reported between telomerase activity assessed in 144 cloned (3.4−03 ± 2.4−03 amoles/μL) and 80 control (2.1−03 ± 1.8−03 amoles/μL) embryos. Conclusions: The results have revealed a moderate shortening of telomeres in the offspring of the clone with respect to control. However, this study did not evidence differences in the two progenies that suggest welfare problems during the first year of life

Avoidable blindness and value based healthcare: more value with a population approach

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An Integrated Approach to Design Fluoro Substituted “Smart” Polymers for Protection of Monumental Buildings

Introduction of fluorinated groups in the structure of either fully acrylic or acrylic - vinyl ether copolymers, is achieved through the use of commercially available or specifically synthesized fluorinated acrylic comonomers. If suitably selected, these fluoroacrylates can allow both control on the macromolecular structure and tailoring of material properties that are relevant for coating applications, such as film-forming behavior, adhesion, water repellency and intrinsic photostability. Several copolymers of fluorinated acrylates and methacrylates with not-fluorinated methacrylates and vinyl ethers have been evaluated in terms of chemical stability under accelerated photoaging conditions, and their behavior as protective coating materials has been studied after application to various stone substrates that are commonly found in ancient buildings and objects of cultural significance

Global gene expression profiling and senescence biomarker analysis of hESC exposed to H2O2 induced non-cytotoxic oxidative stress.

BACKGROUND: Human embryonic stem cells (hESCs) potentially offer new routes to study, on the basis of the Developmental Origins of Health and Disease (DOHaD) concept, how the maternal environment during pregnancy influences the offspring's health and can predispose to chronic disease in later life. Reactive oxygen species (ROS), antioxidant defences and cellular redox status play a key function in gene expression regulation and are involved in diabetes and metabolic syndromes as in ageing. METHODS: We have, therefore, designed an in vitro cell model of oxidative stress by exposing hESCs to hydrogen peroxide (H2O2) during 72 h, in order to resemble the period of preimplantation embryonic development. RESULTS: We have analysed the global gene expression profiles of hESCs (HUES3) exposed to non-cytotoxic H2O2 concentrations, using Illumina microarray HT-12 v4, and we found the differential expression of 569 upregulated and 485 downregulated genes. The most affected gene ontology categories were those related with RNA processing and splicing, oxidation reduction and sterol metabolic processes. We compared our findings with a published RNA-seq profiling dataset of human embryos developed in vitro, thereupon exposed to oxidative stress, and we observed that one of the common downregulated genes between this publication and our data, NEDD1, is involved in centrosome structure and function. CONCLUSIONS: Therefore, we assessed the presence of supernumerary centrosomes and showed that the percentage of cells with more than two centrosomes increased acutely with H2O2 treatment in hESCs (HUES3 and 7) and in a control somatic cell line (Hs27), inducing a premature entry into senescence

FOXP1 circular RNA sustains mesenchymal stem cell identity via microRNA inhibition

Stem cell identity and plasticity are controlled by master regulatory genes and complex circuits also involving non-coding RNAs. Circular RNAs (circRNAs) are a class of RNAs generated from protein-coding genes by backsplicing, resulting in stable RNA structures devoid of free 5' and 3' ends. Little is known of the mechanisms of action of circRNAs, let alone in stem cell biology. In this study, for the first time, we determined that a circRNA controls mesenchymal stem cell (MSC) identity and differentiation. High-throughput MSC expression profiling from different tissues revealed a large number of expressed circRNAs. Among those, circFOXP1 was enriched in MSCs compared to differentiated mesodermal derivatives. Silencing of circFOXP1 dramatically impaired MSC differentiation in culture and in vivo. Furthermore, we demonstrated a direct interaction between circFOXP1 and miR-17-3p/miR-127-5p, which results in the modulation of non-canonical Wnt and EGFR pathways. Finally, we addressed the interplay between canonical and non-canonical Wnt pathways. Reprogramming to pluripotency of MSCs reduced circFOXP1 and non-canonical Wnt, whereas canonical Wnt was boosted. The opposing effect was observed during generation of MSCs from human pluripotent stem cells. Our results provide unprecedented evidence for a regulatory role for circFOXP1 as a gatekeeper of pivotal stem cell molecular networks