The contribution of ionic interactions to the retention of charged glycopeptides was found to be substantial. Thus, O-glycopeptides carrying find more neutral glycans were more retained than O-sialoglycopeptides because negatively charged sialic acid residues were electrostatically repelled by the stationary phase. In addition, glycopeptides differing only in the position of the linkage of the sialic acid moiety could be separated. The same chromatographic behaviour was observed for model systems constituted by a synthetic tetrapeptide covalently conjugated to neutral and sialylated carbohydrates. Subsequent detection of caseinomacropeptide O-glycopeptides was carried out on an electrospray ion trap tandem mass
spectrometer at both positive and negative ionization modes. MS(2) fragmentation at positive ionization mode was valid for determining the glycan structure as the resulting main fragments corresponded to Y(n)-type ions derived from sequential glycosidic bond fragmentation, whilst the fragmentation of the peptide structure was preferably obtained through the formation of b(n)-type ions at the MS(3) stage, allowing the complete structure selleck chemical elucidation of the peptidic chain. Overall, the developed
method allowed the identification and characterization of 41 O-glycopeptides covering all the known glycosylation sites without any previous enrichment step. These results point out that HILIC coupled to multistage MS procedures can be a powerful technique for future glycoproteomic applications.”
“Objective: High restenosis rates are a limitation of peripheral vascular interventions. Previous studies have shown that surgical implantation of a tissue-engineered endothelium onto the adventitia surface of injured
vessels Digestive enzyme regulates vascular repair. In the present study, we developed a particulate formulation of tissue-engineered endothelium and a method to deliver the formulation perivascular to injured blood vessels using a percutaneous, minimally invasive technique.
Methods: Stainless steel stents were implanted in 18 balloon-injured femoral arteries of nine domestic swine, followed by ultrasound-guided percutaneous perivascular injection of gelatin particles containing cultured allogeneic porcine aortic endothelial cells (PAE). Controls received injections of empty particles (matrix) or no perivascular injection (sham) after stent deployment. Animals were sacrificed after 90 days.
Results: Angiographic analysis revealed a significantly greater lumen diameter in the stented segments of arteries treated with PAE/matrix (4.72 +/- 0.12 mm) compared with matrix (4.01 +/- 0.20 mm) or sham (4.03 +/- 0.16 mm) controls (P < .05). Similarly, histologic analysis revealed that PAE/matrix-treated arteries had the greatest lumen area (20.4 +/- 0.7 mm(2); P < .05) compared with controls (16.1 +/- 0.9mm(2) and 17.1 +/- 1.