The Temporal Expression of Adipokines During Spinal Fusion

Background Context Adipokines are secreted by white adipose tissue and have been associated with fracture healing. Our goal was to report the temporal expression of adipokines during spinal fusion in an established rabbit model. Purpose Our goal was to report the temporal expression of adipokines during spinal fusion in an established rabbit model. Study Design The study design included a laboratory animal model. Methods New Zealand white rabbits were assigned to either sham surgery (n=2), unilateral posterior spinal fusion (n=14), or bilateral posterior spinal fusion (n=14). Rabbits were euthanized 1–6 and 10 weeks out from surgery. Fusion was evaluated by radiographs, manual palpation, and histology. Reverse transcription-polymerase chain reaction on the bone fusion mass catalogued the gene expression of leptin, adiponectin, resistin, and vascular endothelial growth factor (VEGF) at each time point. Results were normalized to the internal control gene, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) (2^ΔCt), and control bone sites (2^ΔΔCt). Quantitative data were analyzed by two-factor analysis of variance (p\u3c.05). Results Manual palpation scores, radiograph scores, and histologic findings showed progression of boney fusion over time (p Conclusions Leptin expression is likely associated with the maturation phase of bone fusion. Adiponectin and resistin may play a role early on during the fusion process. Our results suggest that leptin expression may be upstream of VEGF expression during spinal fusion, and both appear to play an important role in bone spinal fusion

NMR Observation of Rattling Phonons in the Pyrochlore Superconductor KOs2O6

We report nuclear magnetic resonance studies on the beta-pyrochlore oxide superconductor KOs2O6. The nuclear relaxation at the K sites is entirely caused by fluctuations of electric field gradient, which we ascribe to highly anharmonic low frequency oscillation (rattling) of K ions. A phenomenological analysis shows a crossover from overdamped to underdamped behavior of the rattling phonons with decreasing temperature and its sudden sharpening below the superconducting transition temperature Tc. Absence of the Hebel-Slichter peak in the relaxation rate at the O sites below Tc also indicates strong electron-phonon coupling.Comment: 4 pages, 3 figure

PdPt alloy nanocubes as electrocatalysts for oxygen reduction reaction in acid media

In this work, PdPt alloy nanocubes with different metal ratios were synthesised in the presence of polyvinylpyrrolidone (PVP). The surface morphology of the PdPt samples was characterised by transmission electron microscopy (TEM). TEM images showed that PdPt nanoparticles were cubic-shaped and the average size of the cubes was about 8–10 nm. Their electrocatalytic activity towards the oxygen reduction reaction (ORR) was studied in 0.5 M H2SO4 using the rotating disc electrode method. All the alloyed catalysts showed enhanced electrocatalytic activity for ORR as compared to the monometallic cubic Pd nanoparticles. Half-wave potential values for PdPt catalysts were comparable with that of Pt nanocubes. From the alloyed catalysts Pd36Pt64 exhibited the highest specific activity, which was only slightly lower than that of cubic Pt nanoparticles. The Koutecky–Levich analysis revealed that the reduction of oxygen proceeded via 4-electron pathway on all the electrocatalysts studied.This research was financially supported by institutional research funding (IUT20-16) of the Estonian Ministry of Education and Research and by the Estonian Research Council (Grant No. 9323) and by Archimedes Foundation (Project No. 3.2.0501.10-0015). KJ thanks the Archimedes Foundation for scholarship. JMF acknowledges financial support from MINECO (Spain), project CTQ2013-44083-P

Shape-Dependent Electrocatalysis: Oxygen Reduction on Carbon-Supported Gold Nanoparticles

Cubic, octahedral and quasi-spherical (two different particle sizes) Au nanoparticles are synthesised and dispersed in a carbon-black powder. The size and morphology of the Au nanocatalysts is confirmed by transmission electron microscopy and X-ray diffraction. Au nanospheres are approximately 5 and 30 nm in diameter, whereas the size of Au octahedra and nanocubes is approximately 40–45 nm. The electrocatalytic activity of these carbon-supported particles towards the oxygen reduction reaction (ORR) is studied in 0.5 M H2SO4 and 0.1 M KOH solutions by using the rotating-disk-electrode method. The specific activity (SA) for O2 reduction is measured, and the highest SA is observed for Au nanocubes supported on carbon. The highest mass activities are found for the smallest Au nanoparticles. Tafel analysis suggests that the mechanism of the ORR on shape-controlled Au/C catalysts is the same as on bulk Au.This research was financially supported by institutional research funding (IUT 20–16) of the Estonian Ministry of Education and Research and by the Estonian Research Council (Grant No. 8380), by Archimedes Foundation (Project No. 3.2.0501.10–0015), by the MCINN-FEDER (Spain) (project CTQ 2010–16271) and by the Generalitat Valenciana (project PROMETEO/2009/045)

Loading effect of carbon-supported platinum nanocubes on oxygen electroreduction

In this work, Vulcan carbon-supported cube-shape Pt nanoparticles with various metal loadings were synthesised in the presence of oleylamine and oleic acid. Surface morphology of different Pt/C samples was examined by transmission electron microscopy (TEM) and their metal loading verified by thermogravimetric analysis (TGA). TEM micrographs showed Pt nanoparticles with a preferential cubic-shape and increased agglomeration of the particles with increasing Pt loading. Electrochemical characterisation of the Pt/C catalysts indicated that the resulting Pt nanoparticles present a preferential (100) surface structure. The electrocatalytic properties of the Pt/C catalysts of different metal loading were evaluated towards the oxygen reduction reaction (ORR) both in acidic and alkaline media employing the rotating disk electrode (RDE) configuration. Interestingly, similar specific and mass activities were found in both solutions revealing that the ORR activities were independent of the Pt loading and suggesting that all the Pt nanocubes contributed as isolated particles.This work was financially supported by institutional research funding (IUT20-16) of the Estonian Ministry of Education and Research. This research was also supported by the EU through the European Regional Development Fund (TK141 “Advanced materials and high-technology devices for energy recuperation systems”). KJ would like to thank Archimedes Foundation for the partial study scholarship. JMF thanks MINECO (Project CTQ2016-76221-P (AEI/FEDER, UE)) and Generalitat Valenciana (Project PROMETEOII/2014/013) for financial support. JSG acknowledges financial support from VITC (Vicerrectorado de Investigación y Transferencia de Conocimiento) of the University of Alicante

Oxygen reduction reaction on carbon-supported palladium nanocubes in alkaline media

Carbon-supported Pd nanocubes with the size of 30, 10 and 7 nm were prepared and their electrocatalytic activity towards the oxygen reduction reaction (ORR) in alkaline solution was studied. For comparison carbon-supported spherical Pd nanoparticles and commercial Pd/C catalyst were used. The catalysts were characterised by transmission electron microscopy, electro-oxidation of carbon monoxide and cyclic voltammetry and the ORR activity was evaluated using the rotating disk electrode method. The ORR on all studied Pd/C catalysts proceeded via four-electron pathway where the rate-limiting step was the transfer of the first electron to O2 molecule. The specific activity of Pd nanocubes was more than two times higher than that of spherical Pd nanoparticles and increased with increasing the particle size.This research was financially supported by institutional research funding (IUT20-16) by the Estonian Ministry of Education and Research and by the Estonian Research Council (Grant No. 9323)

Oxygen electroreduction on carbon-supported Pd nanocubes in acid solutions

The oxygen reduction reaction (ORR) was studied on carbon-supported cubic palladium nanoparticles of different sizes (∼30 nm, ∼10 nm and ∼7 nm). Cetyltrimethylammonium bromide (CTAB) and polyvinylpyrrolidone (PVP) were used as capping agents to prepare the nanocubes and Pd content in the catalyst samples was 20 and 50 wt%. The surface morphology of the prepared materials was studied by transmission electron microscopy (TEM). The catalyst materials were electrochemically characterised by cyclic voltammetry and CO stripping experiments. The rotating disk electrode (RDE) method was employed for ORR studies in 0.5 M H2SO4 and 0.1 M HClO4 solutions. The ORR results revealed that the specific activity of cubic Pd nanoparticles is higher than that of spherical Pd particles and does not depend on the Pd content in the catalyst, but decreases with decreasing the size of Pd nanocubes. Mass activity of Pd nanocubes increased with decreasing the particle size. The ORR proceeds mainly via 4-electron pathway and the reaction mechanism is similar to that on bulk Pd.This research was financially supported by institutional research funding (IUT20-16) of the Estonian Ministry of Education and Research and by the Estonian Research Council (Grant No. 9323). HE thanks the Archimedes Foundation for scholarship. JMF acknowledges financial support from MINECO (Spain), project CTQ2013-44083-P

Endothelium-Derived Netrin-4 Supports Pancreatic Epithelial Cell Adhesion and Differentiation through Integrins α2β1 and α3β1

BACKGROUND: Netrins have been extensively studied in the developing central nervous system as pathfinding guidance cues, and more recently in non-neural tissues where they mediate cell adhesion, migration and differentiation. Netrin-4, a distant relative of Netrins 1-3, has been proposed to affect cell fate determination in developing epithelia, though receptors mediating these functions have yet to be identified. METHODOLOGY/PRINCIPAL FINDINGS: Using human embryonic pancreatic cells as a model of developing epithelium, here we report that Netrin-4 is abundantly expressed in vascular endothelial cells and pancreatic ductal cells, and supports epithelial cell adhesion through integrins α2β1 and α3β1. Interestingly, we find that Netrin-4 recognition by embryonic pancreatic cells through integrins α2β1 and α3β1 promotes insulin and glucagon gene expression. In addition, full genome microarray analysis revealed that fetal pancreatic cell adhesion to Netrin-4 causes a prominent down-regulation of cyclins and up-regulation of negative regulators of the cell cycle. Consistent with these results, a number of other genes whose activities have been linked to developmental decisions and/or cellular differentiation are up-regulated. CONCLUSIONS/SIGNIFICANCE: Given the recognized function of blood vessels in epithelial tissue morphogenesis, our results provide a mechanism by which endothelial-derived Netrin-4 may function as a pro-differentiation cue for adjacent developing pancreatic cell populations expressing adhesion receptors α2β1 and α3β1 integrins

Effect of kidney donation on bone mineral metabolism.

Kidney donation results in reductions in kidney function and lasting perturbations in phosphate homeostasis, which may lead to adverse cardiovascular sequelae. However, the acute effects of kidney donation on bone mineral parameters including regulators of calcium and phosphate metabolism are unknown. We conducted a prospective observational controlled study to determine the acute effects of kidney donation on mineral metabolism and skeletal health. Biochemical endpoints were determined before and after donation on days 1, 2 and 3, 6 weeks and 12 months in donors and at baseline, 6 weeks and 12 months in controls. Baseline characteristic of donors (n = 34) and controls (n = 34) were similar: age (53±10 vs 50±14 years, p = 0.33), BMI (26.3±2.89 vs 25.9±3.65, p = 0.59), systolic BP (128±13 vs 130±6 mmHg, p = 0.59), diastolic BP (80±9 vs 81±9 mmHg, p = 0.68) and baseline GFR (84.4±20.2 vs 83.6±25.2 ml/min/1.73m2, p = 0.89). eGFR reduced from 84.4±20.2 to 52.3±17.5 ml/min/1.73m2 (p<0.001) by day 1 with incomplete recovery by 12 months (67.7±22.6; p = 0.002). Phosphate increased by day 1 (1.1(0.9-1.2) to 1.3(1.1-1.4) mmol/L, p <0.001) but declined to 0.8(0.8-1.0) mmol/L (p<0.001) before normalizing by 6 weeks. Calcium declined on day 1 (p = 0.003) but recovered at 6 weeks or 12 months. PTH and FGF-23 remained unchanged, but α-Klotho reduced by day 1 (p = 0.001) and remained low at 6 weeks (p = 0.02) and 1 year (p = 0.04). In this study, we conclude that kidney donation results in acute disturbances in mineral metabolism characterised by a reduced phosphate and circulating α-Klotho concentration without acute changes in the phosphaturic hormones FGF23 and PTH

HGF Mediates the Anti-inflammatory Effects of PRP on Injured Tendons

Platelet-rich plasma (PRP) containing hepatocyte growth factor (HGF) and other growth factors are widely used in orthopaedic/sports medicine to repair injured tendons. While PRP treatment is reported to decrease pain in patients with tendon injury, the mechanism of this effect is not clear. Tendon pain is often associated with tendon inflammation, and HGF is known to protect tissues from inflammatory damages. Therefore, we hypothesized that HGF in PRP causes the anti-inflammatory effects. To test this hypothesis, we performed in vitro experiments on rabbit tendon cells and in vivo experiments on a mouse Achilles tendon injury model. We found that addition of PRP or HGF decreased gene expression of COX-1, COX-2, and mPGES-1, induced by the treatment of tendon cells in vitro with IL-1β. Further, the treatment of tendon cell cultures with HGF antibodies reduced the suppressive effects of PRP or HGF on IL-1β-induced COX-1, COX-2, and mPGES-1 gene expressions. Treatment with PRP or HGF almost completely blocked the cellular production of PGE2 and the expression of COX proteins. Finally, injection of PRP or HGF into wounded mouse Achilles tendons in vivo decreased PGE2 production in the tendinous tissues. Injection of platelet-poor plasma (PPP) however, did not reduce PGE2 levels in the wounded tendons, but the injection of HGF antibody inhibited the effects of PRP and HGF. Further, injection of PRP or HGF also decreased COX-1 and COX-2 proteins. These results indicate that PRP exerts anti-inflammatory effects on injured tendons through HGF. This study provides basic scientific evidence to support the use of PRP to treat injured tendons because PRP can reduce inflammation and thereby reduce the associated pain caused by high levels of PGE2. © 2013 Zhang et al