Impact of distance from implant center on mechanical circulatory device patient outcomes.

OBJECTIVES: Patients on left ventricular assist device (LVAD) support receive extensive care and education before discharge home. We investigated the impact of patient's residential distance from LVAD implantation center on outcomes and survival. METHODS: A total of 214 patients received a LVAD between 2006 and 2018 at our institution. Patient's residential distance from the LVAD implantation center, LVAD complications, hospitalization, and death were recorded. Patients were divided into two groups: patients living less than or equal to 100 miles (Group 1), patients living more than 100 (Group 2). RESULTS: A total of 106 patients were assigned to Group 1 and 108 patients were assigned to Group 2. Destination therapy was intended in 20% of patients in Group 1 and 34% in Group 2 (p = .023). Mean length of stay was 13 ± 9 days for Group 1 and 21 ± 12 for Group 2 (p < .001). Major postoperative complications were unplanned readmissions due to infections (9% and 12%), gastrointenstinal bleeding (15% and 14%), cerebrovascular accidents (6% and 7.4%), and acute kidney injury (5% and 2%), respectively for Group 1 and Group 2. There was no difference in major complications (all p > .05) and survival between patients in both groups (p > .05). CONCLUSIONS: Distance from implanting center had no impact on adverse outcomes after LVAD implantation. There was a significant increase in hospital stay for patients who live far from the implanting center, suggesting that distance should not be a contraindication when considering patients for LVAD therapy, but plans should be made for prolonged hospital stay or extended local stay near the hospital for close follow-up.

In-situ preparation of N-TiO2/graphene nanocomposite and its enhanced photocatalytic hydrogen production by H2S splitting under solar light.

Highly monodispersed nitrogen doped TiO2 nanoparticles were successfully deposited on graphene (N-TiO2/Gr) by a facile in-situ wet chemical method for the first time. N-TiO2/Gr has been further used for photocatalytic hydrogen production using a naturally occurring abundant source of energy i.e. solar light. The N-TiO2/Gr nanocomposite composition was optimized by varying the concentrations of dopant nitrogen and graphene (using various concentrations of graphene) for utmost hydrogen production. The structural, optical and morphological aspects of nanocomposites were studied using XRD, UV-DRS, Raman, XPS, FESEM, and TEM. The structural study of the nanocomposite shows existence of anatase N-TiO2. Further, the details of the components present in the composition were confirmed with Raman and XPS. The morphological study shows that very tiny, 7-10 nm sized, N-TiO2 nanoparticles are deposited on the graphene sheet. The optical study reveals a drastic change in absorption edge and consequent total absorption due to nitrogen doping and presence of graphene. Considering the extended absorption edge to the visible region, these nanocomposites were further used as a photocatalyst to transform hazardous H2S waste into eco-friendly hydrogen using solar light. The N-TiO2/Gr nanocomposite with 2% graphene exhibits enhanced photocatalytic stable hydrogen production i.e. ∼5941 µmol h(-1) under solar light irradiation using just 0.2 gm nanocomposite, which is much higher as compared to P25, undoped TiO2 and TiO2/Gr nanocomposite. The enhancement in the photocatalytic activity is attributed to 'N' doping as well as high specific surface area and charge carrier ability of graphene. The recycling of the photocatalyst shows a good stability of the nanocomposites. This work may provide new insights to design other semiconductor deposited graphene novel nanocomposites as a visible light active photocatalyst.

Accelerated wound closure of pressure ulcers in aged mice by chitosan scaffolds with and without bFGF.

Pressure ulcers are a significant healthcare concern, especially for elderly populations. Our work served to ameliorate the chronicity of these ulcers by addressing ischemia-reperfusion injury mediated by neutrophils and the concomitant loss of vasculature in these wounds. To this end, chitosan scaffolds loaded with basic fibroblast growth factor (bFGF) contained in gelatin microparticles were developed and tested for clinical relevance in an aged mouse model. Pressure ulcers were induced in aged mice, and efficacy of treatment was assessed. On days 3 and 7, both chitosan and chitosan-bFGF scaffolds significantly accelerated wound closure compared to gauze control. By day 10, all wounds achieved similar closure. Delivery and angiogenic function of bFGF was verified through ELISA and histology. Elevated neutrophil levels were observed in chitosan and chitosan-bFGF groups. Since neutrophil elastase contributes to the proteolytic environments of pressure ulcers, the effect of chitosan on elastase was assessed. In vitro, chitosan inhibited elastase activity. In vivo, elastase protein levels in wounds were reduced with chitosan-bFGF scaffolds by day 10. These results suggest that chitosan is an effective material for growth factor delivery and can help to heal chronic ulcers. Collectively, our data show that chitosan-bFGF scaffolds are effective in accelerating wound closure of pressure ulcers in aged animals.

The effect of chitosan on the migration of neutrophil-like HL60 cells, mediated by IL-8.

Research interest in chitosan stems in part from the demonstrated wound healing properties. The benefits of chitosan as a therapeutic agent appear to be paradoxical because chitosan also elicits neutrophil infiltration indicative of an inflammatory response. While the affinity between chitosan and neutrophils has been well documented, the underlying mechanism is unclear. To our knowledge, no studies have investigated the consequences of chitosan-neutrophil interaction to explain neutrophil migration. To that end, transwell migration assays to chitosan of varying extent of acetylation were conducted using a differentiated model cell line (HL60-PMN) in order to assess the effect of chitosan chemistry and the resultant physical properties such as charge and hydrophobicity on neutrophil migration. As chitosan N-acetylation increased, neutrophil migration increased and chitosan became less positively charged and more hydrophobic. Moreover, HL60-PMN cells secreted the potent neutrophil chemokine IL-8, also known as CXCL8, when exposed to chitosan and IL-8 levels increased with N-acetylation, and migration was inhibited by anti-IL-8 antibodies. Collectively these results suggest that chitosan-neutrophil interaction is encouraged by material properties, results in IL-8 secretion, and causes migration of neutrophils to chitosan. The implication is that the wound healing properties of chitosan may be enhanced through the attenuation of overabundant neutrophils, and thus the inflammatory response, simply by changing chitosan N-acetylation.