Development of a Gene-Activated Scaffold Incorporating Multifunctional Cell-Penetrating Peptides for pSDF-1α Delivery for Enhanced Angiogenesis in Tissue Engineering Applications

Non-viral gene delivery has become a popular approach in tissue engineering, as it permits the transient delivery of a therapeutic gene, in order to stimulate tissue repair. However, the efficacy of non-viral delivery vectors remains an issue. Our lab has created gene-activated scaffolds by incorporating various non-viral delivery vectors, including the glycosaminoglycan-binding enhanced transduction (GET) peptide into collagen-based scaffolds with proven osteogenic potential. A modification to the GET peptide (FLR) by substitution of arginine residues with histidine (FLH) has been designed to enhance plasmid DNA (pDNA) delivery. In this study, we complexed pDNA with combinations of FLR and FLH peptides, termed GET* nanoparticles. We sought to enhance our gene-activated scaffold platform by incorporating GET* nanoparticles into collagen–nanohydroxyapatite scaffolds with proven osteogenic capacity. GET* N/P 8 was shown to be the most effective formulation for delivery to MSCs in 2D. Furthermore, GET* N/P 8 nanoparticles incorporated into collagen–nanohydroxyapatite (coll–nHA) scaffolds at a 1:1 ratio of collagen:nanohydroxyapatite was shown to be the optimal gene-activated scaffold. pDNA encoding stromal-derived factor 1α (pSDF-1α), an angiogenic chemokine which plays a role in BMP mediated differentiation of MSCs, was then delivered to MSCs using our optimised gene-activated scaffold platform, with the aim of significantly increasing angiogenesis as an important precursor to bone repair. The GET* N/P 8 coll–nHA scaffolds successfully delivered pSDF-1α to MSCs, resulting in a significant, sustained increase in SDF-1α protein production and an enhanced angiogenic effect, a key precursor in the early stages of bone repair.     

A 1D High Performance Thin Layer Chromatography Method Validated to Quantify Phospholipids Including Cardiolipin and Monolysocardiolipin from Biological Samples

The aim of this study is to identify high performance thin layer chromatography (HPTLC) conditions allowing the separation and quantification of mammalian cellular phospholipids (PLs) (sphingomyelin, phosphatidylcholine, phosphatidylserine, phosphatidylinositol, phosphatidylethanolamine, and especially phosphatidic acid, cardiolipin, and monolysocardiolipin, these latter two being specifically located in mitochondria membranes). In order to make this method faster and easier, a 1D HPTLC method is chosen, testing several eluents as well as several staining methods. A pre‐conditioning of HPTLC plates with boric acid and a copper staining reagent followed by carbonization are selected for the quality of PL separation and homogeneity of staining. The selected conditions are discussed and the method validation is performed according to the International Conference on Harmonization guidelines. Linearity is effective between 1 and 8 µg and limit of quantification is between 0.5 and 2.3 µg depending on PL classes. Precision measurements show coefficients of variation <6%, and when amounts are close to the detection limit, <12%. Lipid extracts of tumor cell lines or isolated mitochondria are used to assess PL profiles. This shows that the HPTLC method can be used routinely to follow level variations of PLs. Practical Applications: The changes in PL composition play a crucial role in tumor processes and regulate cellular functions modulating cellular signaling or mitochondrial metabolism. The simple and cost‐effective 1D HPTLC method that is developed is applied to lipid extracts of whole tumor cells or hepatocyte‐isolated mitochondria. It is sensitive as well as precise to detect variations of phosphatidic acid or cardiolipin levels linked to physio‐pathological conditions. It can also be used to investigate the composition changes of other membrane PLs. Moreover, with a simultaneous analysis of 14 samples/standards on the same plate (six plates per day), this method is adapted for large series of samples.     

Effects of Spray-Drying Conditions on the Physicochemical Properties of Blackberry Powder

The purpose of this work was to study the effects of spray-drying conditions on the physicochemical characteristics of blackberry powder using a central composite rotatable design. Inlet air temperature (140–180°C) and maltodextrin concentration (5–25%) were employed as independent variables. Moisture content, hygroscopicity, anthocyanin retention, color, powder morphology, and particle size were analyzed. A higher inlet air temperature significantly increased the hygroscopicity of the powder, decreased its moisture content, and led to the formation of larger particles with smooth surfaces. Powders produced with higher maltodextrin concentrations were less hygroscopic, slightly lighter and less red, and had a lower moisture content. Anthocyanin retention was mainly affected by drying temperature due to the heat sensitivity of the pigment. The optimal processing conditions were an inlet air temperature of 140–150°C and maltodextrin concentration of 5–7%. Overall, these results indicate that good quality powders can be obtained by spray drying, with potential applications for the food industry.     

Soft-Chemistry Synthesis, Characterization, and Stabilization of CGO/Al2O3/Pt Nanostructured Composite Powders

Soft-chemistry routes were used to synthesize Ce_0.9Gd_0.1O_1.95-based powders with attractive and stable structural, morphological, and textural properties. In the intermediate temperature range between 500° and 700°C, the average Gd-doped CeO₂ (CGO) crystallite size is in the range 9–22 nm and the specific surface area varies from 43.4 to 8 m²/g. Above 700°C, a phase separation occurs between ceria and gadolinium oxide. Addition of alumina was found to be useful in stabilizing the CGO nanocrystallites at a high temperature and to avoid phase separation. A homogeneous dispersion of Pt nanoparticles (<10 nm at 1000°C) in the CGO materials was found to be possible by post-impregnation, although direct insertion of the Pt precursors during the synthesis led to aggregated particles, with less potential for catalytic applications.     

Application of bacteria involved in the biological sulfur cycle for paper mill effluent purification

In anaerobic wastewater treatment, the occurrence of biological sulfate reduction results in the formation of unwanted hydrogen sulfide, which is odorous, corrosive and toxic. In this paper, the role and application of bacteria in anaerobic and aerobic sulfur transformations are described and exemplified for the treatment of a paper mill wastewater. The sulfate containing wastewater first passes an anaerobic UASB reactor for bulk COD removal which is accompanied by the formation of biogas and hydrogen sulfide. In an aeration pond, the residual COD_organic and the formed dissolved hydrogen sulfide are removed. The biogas, consisting of CH₄ (80-90 vol.%), CO₂ (10-20 vol.%) and H₂S (0.8-1.2 vol.%), is desulfurised prior to its combustion in a power generator thereby using a new biological process for H₂S removal. This process will be described in more detail in this paper. Biomass from the anaerobic bioreactor has a compact granular structure and contains a diverse microbial community. Therefore, other anaerobic bioreactors throughout the world are inoculated with biomass from this UASB reactor. The sludge was also successfully used in investigation on sulfate reduction with carbon monoxide as the electron donor and the conversion of methanethiol. This shows the biotechnological potential of this complex reactor biomass.     

The heat treatment and the gelation are strong determinants of the kinetics of milk proteins digestion and of the peripheral availability of amino acids

This study aimed to determine the kinetics of milk protein digestion and amino acid absorption after ingestion of four dairy matrices by six minipigs: unheated or heated skim milk and corresponding rennet gels. Digestive contents and plasma samples were collected over a 7 h-period after meal ingestion. Gelation of milk slowed down the outflow of the meal from the stomach and the subsequent absorption of amino acids, and decreased their bioavailability in peripheral blood. The gelled rennet matrices also led to low levels of milk proteins at the duodenum. Caseins and β-lactoglobulin, respectively, were sensitive and resistant to hydrolysis in the stomach with the unheated matrices, but showed similar digestion with the heated matrices, with a heat-induced susceptibility to hydrolysis for β-lactoglobulin. These results suggest a significant influence of the meal microstructure (resulting from heat treatment) and macrostructure (resulting from gelation process) on the different steps of milk proteins digestion.     

Newly designed polyacrylamide/dextran gels for electrophoresis protein separation: synthesis and characterization

Newly designed gels for electrophoresis protein separation were synthesized from acrylamide, N,N′‐methylenebis (acrylamide) and dextran mixtures. Radical polymerization was initiated by ammonium persulfate and N,N,N′,N′‐tetramethylethylenediamine. The time dependence of absorbance during polymerization was monitored using UV‐visible spectroscopy. The exothermic polymerization process exhibited a sharp rise of temperature reminiscent of the Trommsdorff effect. The swelling kinetics of the synthesized gels was examined in deionized water and buffer solutions. One of the challenges was to find an alternative to commercial products, sold as mixtures with no detailed chemical contents, commonly used in sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS‐PAGE) for protein separation. For this reason, a systematic comparison was made of the properties of one of the most commonly used commercial gels, Duracryl^? from Genomics Solution Inc., and those of the synthesized polyacrylamide/dextran gels. Copyright © 2011 Society of Chemical Industry     

Dissemination of the Coping Power program: Importance of intensity of counselor training.

This study examined an important but rarely investigated aspect of the dissemination process: the intensity of training provided to practitioners. Counselors in 57 schools were randomly assigned to 1 of 3 conditions: Coping Power–training plus feedback (CP-TF), Coping Power–basic training (CP-BT), or a comparison condition. CP-TF counselors produced reductions in children’s externalizing behavior problems and improvements in children’s social and academic skills in comparison to results for target children in both the comparison and the CP-BT conditions. Training intensity was critical for successful dissemination, although the implementation mechanism underlying this effect remains unclear, as condition effects were not significant for completion of session objectives but were significant for the quality of counselors’ engagement with children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)