Πέμπτη 19 Νοεμβρίου 2020

Modeling of Virtual Mechanical Circulatory Hemodynamics for Biventricular Heart Failure Support

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Abstract

Objective

In this study, a mechanical circulatory support simulation tool was used to investigate the application of a unique device with two centrifugal pumps and one motor for the biventricular assist device (BVAD) support application. Several conditions—including a range of combined left and right systolic heart failure severities, aortic and pulmonary valve regurgitation, and combinations of high and low systemic and pulmonary vascular resistances—were considered in the simulation matrix. Relative advantages and limitations of using the device in BVAD applications are discussed.

Methods

The simulated BVAD pump was based on the Cleveland Clinic pediatric continuous-flow total artificial heart (P-CFTAH), which is currently under development. Different combined disease states (n = 10) were evaluated to model the interaction with the BVAD, considering combinations of normal heart, moderate failure and severe systolic failure of the left and right ventricles, regurgitation of the aortic and pulmonary valves and combinations of vascular resistance. The virtual mock loop simulation tool (MATLAB; MathWorks®, Natick, MA) simulates the hemodynamics at the pump ports using a lumped-parameter model for systemic/pulmonary circulation characteristic inputs (values for impedance, systolic and diastolic ventricular compliance, beat rate, and blood volume), and characteristics of the cardiac chambers and valves.

Results

Simulation results showed that this single-pump BVAD can provide regulated support of up to 5 L/min over a range of combined heart failure states and is suitable for smaller adult and pediatric support. However, good self-regulation of the atrial pressure difference was not maintained with the introduction of aortic valve regurgitation or high systemic vascular resistance when combined with low pulmonary vascular resistance.

Conclusions

This initial in silico study demonstrated that use of the P-CFTAH as a BVAD supports cardiac output and arterial pressure in biventricular heart failure conditions. A similar but larger device would be required for a large adult patient who needs more than 5 L/min of support.

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Urea entrapment in cellulose acetate microparticles obtained by electrospraying

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Abstract

Urea is a widely used source of nitrogen, but its rapid solubilization in water leads to significant wastage on application. Thus, the quest for an efficient and economical polymeric matrix able to encapsulated urea is a long-standing challenge. In this paper, we present a simple and economical method for urea entrapment in cellulose acetate (CA) microparticles produced by the electrospraying process. The morphology and diameter of the microparticles were optimized experimentally by evaluating the solvent composition (binary mixture) and polymer concentration. The electrospraying process parameters, such as particle collection distance, applied voltage and flow rate, were also evaluated. The particle diameter was determined by scanning electron microscopy (SEM) and the CA microparticle characteristics, urea incorporation and in vitro release profile were determined by Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetr y (DSC). The morphological characteristics (shape and porosity) of the CA microparticles were affected by the diffusion rate and CA solubility due to solvent evaporation in the electrospraying process. The SEM images showed monodispersed and spherical CA microparticles with a diameter size of 2.2 ± 0.3 µm. The FTIR spectra and SEM images verified the urea entrapment in the CA microparticles (100 mg/g), and the particle morphology did not appear to be affected. The release of urea from the CA microparticles showed a maximum of 79% after 7 h, which is a significant difference in relation to in vitro urea release. The results obtained using the electrospray technology represent a step forward in the search to improve the incorporation of urea into CA microparticles.

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Overlapping Molecular Pathways Leading to Autism Spectrum Disorders, Fragile X Syndrome, and Targeted Treatments

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Abstract

Autism spectrum disorders (ASD) are subdivided into idiopathic (unknown) etiology and secondary, based on known etiology. There are hundreds of causes of ASD and most of them are genetic in origin or related to the interplay of genetic etiology and environmental toxicology. Approximately 30 to 50% of the etiologies can be identified when using a combination of available genetic testing. Many of these gene mutations are either core components of the Wnt signaling pathway or their modulators. The full mutation of the fragile X mental retardation 1 (FMR1) gene leads to fragile X syndrome (FXS), the most common cause of monogenic origin of ASD, accounting for ~ 2% of the cases. There is an overlap of molecular mechanisms in those with idiopathic ASD and those with FXS, an interaction between various signaling pathways is suggested during the development of the autistic brain. This review summarizes the cross talk between neurobiological pathways found in ASD and FXS. These signaling pathways are currently under evaluation to target specific treatments in search of the reversal of the molecular abnormalities found in both idiopathic ASD and FXS.

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BDNF rs6265 Variant Alters Outcomes with Levodopa in Early-Stage Parkinson’s Disease

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Abstract

Disease outcomes are heterogeneous in Parkinson's disease and may be predicted by gene variants. This study investigated if the BDNF rs6265 single nucleotide polymorphism (SNP) is associated with differential outcomes with specific pharmacotherapy treatment strategies in the "NIH Exploratory Trials in PD Long-term Study 1" (NET-PD LS-1, n = 540). DNA samples were genotyped for the rs6265 SNP and others (rs11030094, rs10501087, rs1491850, rs908867, and rs1157659). The primary measures were the Unified Parkinson's Disease Rating Scale (UPDRS) and its motor component (UPDRS-III). Groups were divided by genotype and treatment regimen (levodopa monotherapy vs levodopa with other medications vs no levodopa). T allele carriers were associated with worse UPDRS outcomes compared to C/C subjects when treated with levodopa monotherapy (+ 6 points, p = 0.02) and to T allele carriers treated with no levodopa treat ment strategies (UPDRS: + 8 points, p = 0.01; UPDRS-III: + 6 points, p = 0.01). Similar effects of worse outcomes associated with levodopa monotherapy were observed in the BDNF rs11030094, rs10501087, and rs1491850 SNPs. This study suggests the levodopa monotherapy strategy is associated with worse disease outcomes in BDNF rs6265 T carriers. Pending prospective validation, BDNF variants may be precision medicine factors to consider for symptomatic treatment decisions for early-stage PD patients.

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Green synthesis of CuFeS 2 nanoparticles using mimosa leaves extract for photocatalysis and supercapacitor applications

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Abstract

We successfully synthesized CuFeS2 nanoparticles (NPs) using a simple synthesis method mediated by touch me not (Mimosa pudica) leaves extract. X-ray diffraction (XRD) was used to analyze the structural properties, and it shows that the CuFeS2 NPs have a tetragonal structure and quasi-pyramidal NPs of an average crystallite size of 31.0 nm with a secondary phase of few minor peaks of covellite (CuS). The optical characterization showed that CuFeS2 NPs have band gap energy ranges of 1.98–2.46 eV for different annealing temperatures. The electrochemical properties of the CuFeS2 NPs were investigated using cyclic voltammetry (CV), galvanostatic charge discharge (GCD), and electrochemical impedance spectroscopy (EIS). An appreciable value of specific capacitance of 501.4 F/g was obtained at a scan rate of 10 mV/s for the CuFeS2 NPs annealed at 250 °C which can be said to be within the optimum ideal annealing temperature for CuFeS2 NPs. The CuFeS2 NPs was used in the photodegradation of methylene blue (MB) under of solar irradiation. The highest rate constant of 3.1 × 10−2 min−1 and degradation efficiency of 98% were obtained for the unannealed CuFeS2 NPs with good stability after three cycles. Therefore, the synthesized CuFeS2 NPs were obtained using a Mimosa pudica leaves extract prospective application in both electrochemical energy storage devices and treatment of water contaminants. GO was added to increase the active sites for these ions, surface area, and conductivity of these electrodes for enhanced supercapacitive performance.

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Laparoscopic Greater Curvature Plication for the Treatment of Obesity: a Systematic Review

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Abstract

Background

During the last decade, laparoscopic greater curvature plication (LGCP) has been used as a bariatric procedure for the treatment of obesity, regarded as less invasive and less expensive than other surgical bariatric procedures. We aimed to systematically review the literature and highlight recent clinical data regarding outcomes of LGCP in the treatment of obesity.

Methods

A comprehensive research of Pubmed database on LGCP was performed. The search was conducted on the first of May 2020 and was not limited to any date range. Outcomes of interest were surgical technique, postoperative complications, weight loss outcomes, comorbidities improvement or resolution, and revisional surgeries after technical failure or weight regain.

Results

Fifty-three articles were eligible for inclusion, with 3103 patients undergoing LGCP (mean age: 13.8–55 years). Mean preoperative body mass index (BMI) ranged from 31.2 to 47.8 kg/m2. Mean operative time ranged from 48 to 193 min. Length of hospital stay ranged from 0.75 to 7.2 days. Most studies provided postoperative follow-up up to 12 months. Mean percentage of excess weight loss (%EWL) ranged from 30.2 to 71.1% and 35 to 77.1% at 6 and 12 months post-LGCP, respectively. Only one study followed patients for more than 10 years and mean %EWL at 1, 5, and 10 years was 67%, 55%, and 42%, respectively.

Conclusion

LGCP seems to be an acceptable surgical procedure for the treatment of obesity, especially in centers having a low medical budget. However, most existing comparative studies report superiority of LSG regarding weight loss.

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A Randomized, Controlled Trial Comparing the Impact of a Low-Calorie Ketogenic vs a Standard Low-Calorie Diet on Fat-Free Mass in Patients Receiving an Elipse™ Intragastric Balloon Treatment

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Abstract

Background

The Elipse™ intragastric balloon (EIGB) is a new swallowable balloon for weight loss (WL). Preserving metabolically active fat-free mass (FFM) and resting metabolic rate (RMR) during WL are crucial to maximize fat mass (FM) loss. After EIGB placement, a standard low-calorie diet (LCD) is generally prescribed. A low-calorie ketogenic diet (LCKD) has proven to be safe and effective in reducing FM while preserving FFM and RMR.

Objective

To prospectively compare the effects on WL, FM, FFM, and RMR in two groups of patients who were randomized to two different diets: LCKD and a standard LCD after EIGB placement.

Methods

WL, FM, FFM, and RMR were measured before EIGB and at 4 months in 48 patients who received either a LCKD (n = 24) or a standard LCD (n = 24). Compliance in following the prescribed diet was determined with food frequency questionnaires in all patients. The impact of LCKD and LCD on renal function was also evaluated.

Results

The LCKD group showed a significantly lower decrease in FFM and RMR when compared with the LCD group (3.55 vs 14.3%, p < 0.001; 9.79 vs 11.4%, p < 0.001, respectively). FM decreased more significantly with LCKD compared to LCD (41.6 vs 33.1%, p = 0.0606). Compliance in following the prescribed diets, without negative impact on renal function, was found.

Conclusion

Based on our findings, despite the small sample size, we were able to support the hypothesis that LCKD is associated with an increased FM loss while reducing the FFM loss and the RMR, without interfering with renal function after EIGB.

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