Improving the Study of Protein Glycosylation with New Tools for Glycopeptide Enrichment

High confidence methods are needed for determining the glycosylation profiles of complex biological samples as well as recombinant therapeutic proteins. A common glycan analysis workflow involves liberation of N-glycans from glycoproteins with PNGase F or O-glycans by hydrazinolysis prior to their analysis. This method is limited in that it does not permit determination of glycan attachment sites. Alternative proteomics-based workflows are emerging that utilize site-specific proteolysis to generate peptide mixtures followed by selective enrichment strategies to isolate glycopeptides. Methods designed for the analysis of complex samples can yield a comprehensive snapshot of individual glycans species, the site of attachment of each individual glycan and the identity of the respective protein in many cases. This chapter will highlight advancements in enzymes that digest glycoproteins into distinct fragments and new strategies to enrich specific glycopeptides

Research of psychotropic drug mixtures using high-pressure liquid chromatography in hasty poisoning cases

The qualitative and quantitative method of determination of amitryptilin, codeine and fluoxetine in the mixture using high-pressure liquid chromatography is described in this paper. Chromatogram is presented which shows, that preparations are fully separated and do not interfere each others analysis. Tables with chromatographical separation characteristics are also presented. Proposed calibration curves of quantitative analysis and calculated medium relative error of quantitative ascertainment for every preparation of the mixture are shown. Final conclusion: method is applicable for qualitative and quantitative analysis of amitryptiline, fluoxetine and codeine in the mixture in hasty poisoning cases

In vivo incorporation of an azide-labeled sugar analog to detect mammalian glycosylphosphatidylinositol molecules isolated from the cell surface

AbstractN-Acetylgalactosamine (GalNAc) linked to the first mannose of glycosylphosphatidylinositol (GPI) core has been previously reported to be heterogeneously present on some mammalian GPI-anchored proteins. Here we present a method for profiling GalNAc-containing GPI-anchored proteins in mammalian cells by metabolic labeling with tetraacetylated N-azidoacetylgalactosamine (GalNAz) followed by biotinylation of the incorporated sugar analog. We have labeled both endogenous and recombinant GPI-anchored proteins with GalNAz, and demonstrated that the azide-activated sugar gets incorporated into the GPI glycan, likely as an unsubstituted side branch of the core structure. GalNAz was detected only on GPI molecules attached to proteins, and not on GPI precursors, indicating that GalNAc modification takes place after the GPI anchor is transferred to protein. We have highlighted the utility of this cell labeling approach by demonstrating the ability to examine specific GalNAc-containing GPI-anchored proteins isolated non-destructively from separate membrane domains (apical and basolateral) in polarized epithelial cells. This study represents the first demonstration of site-specific in vivo labeling of a GPI moiety with a synthetic sugar analog

IJOMEH 2010;23(4) TRENDS IN THE INCIDENCE OF OCCUPATIONAL DISEASES IN LITHUANIA BETWEEN 1999 AND 2008

Abstract Objectives: The aim of the study was to investigate the trends in the incidence of occupational diseases in Lithuania during the period of 1999-2008. The analysis concerned both the individuals with diagnosed disease(s) and the number of diagnosed cases. Material and Methods: Incidence rates were calculated using data from the Republic of Lithuania National Register of Occupational Diseases and data on the employed population provided by the government Department of Statistics. The rates were age-standardized using the direct standardization method. The changes in the incidence rates throughout the study period were analyzed using segmented regression calculated with the JOINPOINT (v. 3.3.1) statistical software. We determined joinpoints in the dynamic lines of the incidence rates and calculated mean annual absolute change and mean annual relative (percentage) change for each period. Results and Conclusions: During the study period, the number of occupational diseases was, on average, 1.5 times as high as the number of individuals diagnosed with such diseases. Joinpoint positions in the dynamic lines of the incidence rates coincided for individuals with occupational diseases and for the cases of occupational diseases. The incidence was found to slightly increase during the period of 1999-2003, then to rise more rapidly during that of 2003-2006, and to decrease from 2006 to 2008