ABSTRACT
Due to the heterogeneous and isomeric nature of glycans, the development of an advanced separation of distinct glycan isomers is essential for glycan research and application. In this study, we utilized porous graphite carbon (PGC) chromatography for the separation of isomeric oligosaccharides without reduction or chemical derivatization at 190 °C in a custom-built heating oven. Furthermore, the fine structures of glycan isomers could be identified by using ultrahigh temperature PGC liquid chromatography mass spectrometry (UHT-PGC-LCMS). A nonreduced hydrolyzed dextran was applied to verify the performance of UHT-PGC. When the temperature of the PGC column was increased from 25 to 190 °C, the liquid chromatography separation power of the nonreduced dextran ladder significantly increased. The advantage of the UHT-PGC column was its high peak capacity with gradient elution in 10 min at 190 °C, 6700 psi, and a 250 µL/min flow rate for native glycan analysis. Four synthetic Lewis antigen isomers were used to elucidate the separation effectiveness in UHT-PGC. Moreover, mass spectrometry-based sequencing to generate specific diagnostic ions from the four synthetic Lewis antigens was used to predict isomeric glycans based on the relative intensity ratio (RIR) of diagnostic ions. The intensities of the diagnostic ions of synthetic isomers were used to identify each isomer of the fucosylated glycan. The results clearly showed that terminal Lewis A and X residues were in the 3- and 6-arms of N-glycan, respectively.
Subject(s)
Chromatography, Liquid/methods , Fucose/chemistry , Fucose/isolation & purification , Graphite/chemistry , Tandem Mass Spectrometry/methods , Temperature , Dextrans/chemistry , Glycosylation , Hydrolysis , Ions , Isomerism , Polysaccharides/chemistry , Polysaccharides/isolation & purification , Porosity , Time FactorsABSTRACT
Heterotopic pancreas causing small bowel intussusception is rare. We report the case of a 24-year-old woman who presented with intermittent episodes of abdominal cramping and pain that had persisted for 10 days. A target-shaped lesion consisting of multiple concentric rings was found on the left side on contrast-enhanced computed tomography. Surgical intervention demonstrated jejunal intussusception caused by a jejunal heterotopic pancreas. Microscopically, several nesidioblastoses of pancreas were identified. Although very rare, small intestinal pancreatic rests may cause subacute bowel obstruction.
