Blockwise synthesis of polylactosamine fragments and keratan sulfate oligosaccharides comprised of dimeric Galß(1 → 4)GlcNAc6Sß.

In this paper, the chemical synthesis of polylactosamine fragments up to docosasaccharide (22-mer) via the blockwise synthetic approach is reported. We used suitably protected tetrasaccharide and octasaccharide sequences as key building blocks. The use of such large building blocks as glycosyl donors and acceptors enabled the rapid construction of polysaccharide frameworks. Furthermore, the coupling reaction between these large building blocks facilitated the purification of glycosylated products, for which size exclusion column chromatography is highly effective. Then, we applied the building blocks to the synthesis of keratan sulfate glycan, which is partially sulfated poly-N-acetyllactosamine. Consequently, we achieved the synthesis of the octasaccharide of a keratan sulfate glycan comprised of a repeating Galß(1 â†’ 4)GlcNAc6Sß disaccharide unit.

Magnetic resonance enterocolonography in detecting erosion and redness in intestinal mucosa of patients with Crohn's disease.

BACKGROUND AND AIM: In Crohn's disease (CD), assessment of disease activity and extension is important for clinical management. Endoscopy is the most reliable tool for evaluating disease activity in these patients and it distinguishes between lesions based on ulcer, erosion, and redness. Magnetic resonance imaging (MRI) is less invasive than endoscopy; however, the sensitivity of MRI in detecting lesions is believed to be lower, and whether MRI can detect milder lesions has not been studied. The aim of this study was to compare the detection ability of magnetic resonance enterocolonography (MREC) with ileocolonic endoscopy in patients with CD. METHODS: A total of 27 patients with CD underwent both MREC and ileocolonoscopy. There were 55 lesions (18 ileum and 37 colon) endoscopically detected, and the findings of MREC were compared with each ileocolonoscopic finding to determine sensitivity and specificity. RESULTS: For a positive lesion defined as having at least one of the following: wall thickness, edema, diffusion-weighted imaging (DWI) high intensity and relative contrast enhancement (RCE) on MREC, the sensitivities were 100% for ulcer, 84.6% for erosion, and 52.9% for redness, suggesting an ability to detect milder lesions such as erosion or redness. Moreover, RCE values were well correlated with the severity of endoscopically identified active lesions. CONCLUSION: MREC findings may be useful not only for evaluation of ulcers, but also for detection of endoscopically identified milder lesions in CD, suggesting a clinical usefulness of MREC for disease detection and monitoring.