Multi-Modal, Surface-Focused Anticoagulation Using Poly-2-methoxyethylacrylate Polymer Grafts and Surface Nitric Oxide Release

This study examines platelet adhesion on surfaces that combine coatings to limit protein adsorption along with “anti-platelet” nitric oxide (NO) release. Uncoated and poly-2-methoxyethylacrylate (PMEA) coated, gas permeable polypropylene (PP) membranes were placed in a bioreactor to separate plasma and gas flows. Nitrogen with 100/500/1000 ppm of NO was supplied to the gas side as a proof of concept. On the plasma side, platelet rich plasma (PRP, 1 × 108 cell/mL) was recirculated at low (60)/high (300) flows (mL/min). After 8 hours, adsorbed platelets on PP was quantified via a lactate dehydrogenase assay. Compared to plain PP, the PMEA coating alone reduced adsorption by 17.4 ± 9.2% and 29.6 ± 16.6% at low and high flow (p \u3c 0.05), respectively. NO was more effective at low plasma flow. At 100 and 500 ppm of NO, adsorption fell by 37.9 ± 6.1% and 100 ± 4.7%, (p \u3c 0.001), on plain PP. At high flow with 100, 500, and 1000 ppm of NO, adsorption reduced by 17.9 ± 17.8%, 46.4 ± 23.2%, and 100 ± 4.8%, (p \u3c 0.001), respectively. On PMEA-coated PP with only 100 ppm, adsorption fell by 69.7 ± 6.8 and 65.6% ± 16.9%, (p \u3c 0.001), at low and high flows respectively. Therefore, the combination of an anti-adsorptive coating with NO has great potential to reduce platelet adhesion and coagulation at biomaterial surfaces

Shells around black holes: the effect of freely specifiable quantities in Einstein's constraint equations

We solve Einstein's constraint equations in the conformal thin-sandwich decomposition to model thin shells of non-interacting particles in circular orbit about a non-rotating black hole. We use these simple models to explore the effects of some of the freely specifiable quantities in this decomposition on the physical content of the solutions. Specifically, we adopt either maximal slicing or Kerr-Schild slicing, and make different choices for the value of the lapse on the black hole horizon. For one particular choice of these quantities the resulting equations can be solved analytically; for all others we construct numerical solutions. We find that these different choices have no effect on our solutions when they are expressed in terms of gauge-invariant quantities.Comment: 9 pages, 4 figure

Effects of Emulsion Composition on Pulmonary Tobramycin Delivery During Antibacterial Perfluorocarbon Ventilation

Background: The effectiveness of inhaled aerosolized antibiotics is limited by poor ventilation of infected airways. Pulmonary delivery of antibiotics emulsified within liquid perfluorocarbon [antibacterial perfluorocarbon ventilation (APV)] may solve this problem through better airway penetration and improved spatial uniformity. However, little work has been done to explore emulsion formulation and the corresponding effects on drug delivery during APV. This study investigated the effects of emulsion formulation on emulsion stability and the pharmacokinetics of antibiotic delivery via APV. Methods: Gravity-driven phase separation was examined in vitro by measuring emulsion tobramycin concentrations at varying heights within a column of emulsion over 4 hours for varying values of fluorosurfactant concentration (Cfs?=?5?48?mg/mL H2O). Serum and pulmonary tobramycin concentrations in rats were then evaluated following pulmonary tobramycin delivery via aerosol or APV utilizing sufficiently stable emulsions of varying aqueous volume percentage (Vaq?=?1%?5%), aqueous tobramycin concentration (Ct?=?20?100?mg/mL), and Cfs (15 and 48?mg/mL H2O). Results: In vitro assessment showed sufficient spatial and temporal uniformity of tobramycin dispersion within emulsion for Cfs?≥15?mg/mL H2O, while lower Cfs values showed insufficient emulsification even immediately following preparation. APV with stable emulsion formulations resulted in 5?22 times greater pulmonary tobramycin concentrations at 4 hours post-delivery relative to aerosolized delivery. Concentrations increased with emulsion formulations utilizing increased Vaq (with decreased Ct) and, to a lesser extent, increased Cfs. Conclusions: The emulsion stability necessary for effective delivery is retained at Cfs values as low as 15?mg/mL H2O. Additionally, the pulmonary retention of antibiotic delivered via APV is significantly greater than that of aerosolized delivery and can be most effectively increased by increasing Vaq and decreasing Ct. APV has been further proven as an effective means of pulmonary drug delivery with the potential to significantly improve antibiotic therapy for lung disease patients.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140106/1/jamp.2015.1235.pd

HUMAN ADIPOSE-DERIVED STEM CELLS ATTENUATE CIGARETTE SMOKE INDUCED BONE MARROW HYPOPLASIA VIA SECRETION OF ANTI-INFLAMMATORY CYTOKINE TSG-6

poster abstractIntroduction We have previously observed bone marrow (BM) hypo-plasia in a murine model of chronic smoking, which was ameliorated by mu-rine adipose-derived stromal cells (ASC). This study was designed to test the hypothesis that ASC exert their marrow protective effects through key paracrine factors. Methods Mice (NSG or C57BL/6) were exposed to ciga-rette smoke (CS) for 1 day to 6 months. Human ASC or ASC conditioned media were administered through intravenous (i.v.) or intraperitoneal (i.p.) injections. Secretion of TSG-6 from ASC in response to TNF alpha and IL-1 beta were measured by ELISA. Expression of TSG-6 in ASC was knocked down by siRNA. BM hematopoietic progenitors were quantified by colony forming-unit assays. Possible engrafted human ASC in mouse BM were ex-amined by anti-human nuclei staining. Results The myelossupressive effect of cigarette smoking occurred acutely (1 day: 65.6% of nonsmoking control, NSC, p0.05) or ASC conditioned media (105.7% NSC, p>0.05). Inflammatory cytokines (TNF alpha and IL-1 beta) elevated in smokers (Kuschner et al, 1996; de Maat et al, 2002) demonstrated strong cross-species stimulatory effects on secretions of an anti-inflammatory cytokine, TSG-6 from ASC (TNF alpha: 8.7 +/- 1.3 fold, IL-1 beta: 8.2 +/- 1.1 fold). Knocking down TSG-6 (>90%) abolished the marrow-protective effect of ASC. No human cells were detected in recipient mouse bone marrow. Conclusions The pro-tective effects of ASC against smoking-induced myelosuppression are medi-ated by trophic factors rather than cell engraftment or differentiation. TSG-6 appears to play a significant role in the modulatory pathway: smoke--inflammatory cytokine release--TSG6 secretion from ASC--bone marrow protection

Characterization of a Reverse-Phase Perfluorocarbon Emulsion for the Pulmonary Delivery of Tobramycin

Background: Aerosolized delivery of antibiotics is hindered by poor penetration within distal and plugged airways. Antibacterial perfluorocarbon ventilation (APV) is a proposed solution in which the lungs are partially or totally filled with perfluorocarbon (PFC) containing emulsified antibiotics. The purpose of this study was to evaluate emulsion stability and rheological, antibacterial, and pharmacokinetic characteristics. Methods: This study examined emulsion aqueous droplet diameter and number density over 24?hr and emulsion and neat PFC viscosity and surface tension. Additionally, Pseudomonas aeruginosa biofilm growth was measured after 2-hr exposure to emulsion with variable aqueous volume percentages (0.25, 1, and 2.5%) and aqueous tobramycin concentrations (Ca=0.4, 4, and 40?mg/mL). Lastly, the time course of serum and pulmonary tobramycin concentrations was evaluated following APV and conventional aerosolized delivery of tobramycin in rats. Results: The initial aqueous droplet diameter averaged 1.9±0.2??m with little change over time. Initial aqueous droplet number density averaged 3.5±1.7?109 droplets/mL with a significant (p<0.01) decrease over time. Emulsion and PFC viscosity were not significantly different, averaging 1.22±0.03?10?3 Pa·sec. The surface tensions of PFC and emulsion were 15.0±0.1?10?3 and 14.6±0.6?10?3 N/m, respectively, and the aqueous interfacial tensions were 46.7±0.3?10?3 and 26.9±11.0?10?3 N/m (p<0.01), respectively. Biofilm growth decreased markedly with increasing Ca and, to a lesser extent, aqueous volume percentage. Tobramycin delivered via APV yielded 2.5 and 10 times larger pulmonary concentrations at 1 and 4?hr post delivery, respectively, and significantly (p<0.05) lower serum concentrations compared with aerosolized delivery. Conclusions: The emulsion is bactericidal, retains the rheology necessary for pulmonary delivery, is sufficiently stable for this application, and results in increased pulmonary retention of the antibiotic.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140105/1/jamp.2013.1058.pd

Fabrication and In vivo Thrombogenecity Testing of Nitric Oxide Generating Artificial Lungs

Hollow fiber artificial lungs are increasingly being used for long-term applications. However, clot formation limits their use to 1–2 weeks. This study investigated the effect of nitric oxide generating (NOgen) hollow fibers on artificial lung thrombogenicity. Silicone hollow fibers were fabricated to incorporate 50 nm copper particles as a catalyst for NO generation from the blood. Fibers with and without (control) these particles were incorporated into artificial lungs with a 0.1 m2 surface area and inserted in circuits coated tip-to-tip with the NOgen material. Circuits (N = 5/each) were attached to rabbits in a pumpless, arterio-venous configuration and run for 4 h at an activated clotting time of 350–400 s. Three control circuits clotted completely, while none of the NOgen circuits failed. Accordingly, blood flows were significantly higher in the NOgen group (95.9 ± 11.7, p \u3c 0.01) compared to the controls (35.2 ± 19.7; mL/min), and resistance was significantly higher in the control group after 4 h (15.38 ± 9.65, p \u3c 0.001) than in NOgen (0.09 ± 0.03; mmHg/mL/min). On the other hand, platelet counts and plasma fibrinogen concentration expressed as percent of baseline in control group (63.7 ± 5.7%, 77.2 ± 5.6%; p \u3c 0.05) were greater than those in the NOgen group (60.4 ± 5.1%, 63.2 ± 3.7%). Plasma copper levels in the NOgen group were 2.8 times baseline at 4 h (132.8 ± 4.5 μg/dL) and unchanged in the controls. This study demonstrates that NO generating gas exchange fibers could be a potentially effective way to control coagulation inside artificial lungs

Achieving One‐Step Surface Coating of Highly Hydrophilic Poly(Carboxybetaine Methacrylate) Polymers on Hydrophobic and Hydrophilic Surfaces

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108623/1/admi201400071.pd

Complementary Embryonic and Adult Cell Populations Enhance Myocardial Repair in Rat Myocardial Injury Model

We compared the functional outcome of Isl-1+ cardiac progenitors, CD90+ bone marrow-derived progenitor cells, and the combination of the two in a rat myocardial infarction (MI) model. Isl-1+ cells were isolated from embryonic day 12.5 (E12.5) rat hearts and expanded in vitro. Thy-1+/CD90+ cells were isolated from the bone marrow of adult Sprague-Dawley rats by immunomagnetic cell sorting. Six-week-old female Sprague-Dawley rats underwent permanent left anterior descending (LAD) coronary artery ligation and received intramyocardial injection of either saline, Isl-1+ cells, CD90+ cells, or a combination of Isl-1+ and CD90+ cells, at the time of infarction. Cells were delivered transepicardially to the peri-infarct zone. Left ventricular function was assessed by transthoracic echocardiography at 1- and 4-week post-MI and by Millar catheterization (-dP/dt and +dP/dt) at 4-week post-MI. Fluorescence in situ hybridization (Isl-1+cells) and monochrystalline iron oxide nanoparticles labeling (MION; CD90+ cells) were performed to assess biodistribution of transplanted cells. Only the combination of cells demonstrated a significant improvement of cardiac function as assessed by anterior wall contractility, dP/dt (max), and dP/dt (min), compared to Isl-1+ or CD90+ cell monotherapies. In the combination cell group, viable cells were detected at week 4 when anterior wall motion was completely restored. In conclusion, the combination of Isl-1+ cardiac progenitors and adult bone marrow-derived CD90+ cells shows prolonged and robust myocardial tissue repair and provides support for the use of complementary cell populations to enhance myocardial repair

Phenotypic and pharmacogenetic evaluation of patients with thiazide-induced hyponatremia.

Thiazide diuretics are among the most widely used treatments for hypertension, but thiazide-induced hyponatremia (TIH), a clinically significant adverse effect, is poorly understood. Here, we have studied the phenotypic and genetic characteristics of patients hospitalized with TIH. In a cohort of 109 TIH patients, those with severe TIH displayed an extended phenotype of intravascular volume expansion, increased free water reabsorption, urinary prostaglandin E2 excretion, and reduced excretion of serum chloride, magnesium, zinc, and antidiuretic hormone. GWAS in a separate cohort of 48 TIH patients and 2,922 controls from the 1958 British birth cohort identified an additional 14 regions associated with TIH. We identified a suggestive association with a variant in SLCO2A1, which encodes a prostaglandin transporter in the distal nephron. Resequencing of SLCO2A1 revealed a nonsynonymous variant, rs34550074 (p.A396T), and association with this SNP was replicated in a second cohort of TIH cases. TIH patients with the p.A396T variant demonstrated increased urinary excretion of prostaglandin E2 and metabolites. Moreover, the SLCO2A1 phospho-mimic p.A396E showed loss of transporter function in vitro. These findings indicate that the phenotype of TIH involves a more extensive metabolic derangement than previously recognized. We propose one mechanism underlying TIH development in a subgroup of patients in which SLCO2A1 regulation is altered.This work was supported by an Academy of Medical Sciences grant for clinical lecturers (to JSW and MG), British Heart Foundation grant PG/09/089 (to KMO), the National Institute for Health Research (NIHR) Royal Brompton Cardiovascular Biomedical Research Unit (to JSW and SC), the Fondation Leducq (to JSW and SC), and the British Heart Foundation (to JSW and SC). MDT holds a Medical Research Council Senior Clinical Fellowship (G0902313). This work was supported by the Medical Research Council (grant numbers G510364 and G1000861). This research used the ALICE and SPECTRE High Performance Computing Facilities at the University of Leicester

Testing gravitational-wave searches with numerical relativity waveforms: Results from the first Numerical INJection Analysis (NINJA) project

The Numerical INJection Analysis (NINJA) project is a collaborative effort between members of the numerical relativity and gravitational-wave data analysis communities. The purpose of NINJA is to study the sensitivity of existing gravitational-wave search algorithms using numerically generated waveforms and to foster closer collaboration between the numerical relativity and data analysis communities. We describe the results of the first NINJA analysis which focused on gravitational waveforms from binary black hole coalescence. Ten numerical relativity groups contributed numerical data which were used to generate a set of gravitational-wave signals. These signals were injected into a simulated data set, designed to mimic the response of the Initial LIGO and Virgo gravitational-wave detectors. Nine groups analysed this data using search and parameter-estimation pipelines. Matched filter algorithms, un-modelled-burst searches and Bayesian parameter-estimation and model-selection algorithms were applied to the data. We report the efficiency of these search methods in detecting the numerical waveforms and measuring their parameters. We describe preliminary comparisons between the different search methods and suggest improvements for future NINJA analyses.Comment: 56 pages, 25 figures; various clarifications; accepted to CQ