Glycoprotein profile assessed by1h-nmr as a global inflammation marker in patients with HIV infection. A prospective study

Plasma glycoproteins are a composite biomarker of inflammation and can be detected byH-NMR. The aim of this study was to prospectively appraise the clinical value of plasma glycopro-teins assessed byH-NMR in people living with HIV (PLWH). A total of 221 patients with HIV infection were recruited and studied at baseline and at 48 and 144 weeks. Patients were distributed into two groups according to baseline CD4 T-cell number below or above 200 cells/µL. Patients with fewer than 200 cells/µL were distributed into the responders and nonresponders according to antiretroviral therapy (ART) response at 144 weeks. Glycoprotein concentrations were determined byH-NMR arising from the protein bond N-acetylglucosamine and N-acetylgalactosamine signals (GlycA); and N-acetylneuraminic acid signal (GlycB) associated with the sugar-protein bond con-centration and aggregation state (shapes (height/width)). Basal glycoprotein concentrations were higher in patients with < 200 CD4 T-cell/µL (Glyc A: 1040(917.9-1199.1) vs. 950.4(845.5-1050.9), p < 0.001, and Glyc B: 521(440.3-610.3) vs. 468.6(417.9-507.0) µ mol/L, p < 0.001) being reduced by ART. The height/width (H/W) ratio was the parameter showing a better association with this clinical sta-tus. Baseline glycoproteins predict the condition of responder/nonresponder. In this study,H-NMR glycoproteins provide novel insights to assess inflammation status and have prognostic value in PLWH

Short-Range Order in Polyethylene Melts: Identification and Characterization

Experimental results by Fisher et al. [Faraday Discuss. Chem. Soc. 1979, 68, 26] showed the existence of local orientational correlations of segments of the n-alkane molecules in the liquid state. Since the estimated correlation volume is below 10(3) angstrom(3), molecular dynamics simulations appear to be a suitable method for their identification and characterization. We used molecular dynamics to fully characterize short-range order in polyethylene melts. The characterization started by identifying sequences of aligned segments in chains, each one having at least one Kuhn monomer in length. Afterward, a search was made for interactions of a tagged aligned chain segment with others fulfilling the same condition, laying within a limiting separation distance (18 angstrom) and making a limiting orientation angle (40 degrees). When, at least, four interactions are counted, a short-range ordered region is defined. Chain placement in these regions has similarities to that of the unit cell at the solid phase, although with different separation distances and angle. Overall, short-range order resembles a dynamic uniaxial nematic phase, the local order parameter increasing with the chain length in agreement with experimental results. Segments at the ordered regions persist over time, for times longer than the Rouse relaxation time of the chain. Those in random conformational sequences between the ordered regions have a mass distribution in agreement with the Flory distribution, with a number-average value comparable to experimental results for the molecular mass between entanglements