Sulfation of cellulose with sulfur-trioxideeimethyl sulfoxide

A novel function of N-cadherin and Connexin43: marked enhancement of alkaline phosphatase activity in rat calvarial osteoblast exposed to sulfated hyaluronan

In this study, we examined the interaction of the osteoblast which forms bone and sulfated hyaluronan (SHya). For the purpose of the creation of a new functional polysaccharide, we introduced a sulfate group in hyaluronan (Hya) of high molecular weight, and SHya of high molecular weight could be obtained for the first time. When rat calvarial osteoblast (rOB) cells were cultured with a high concentration of SHya, they formed aggregated spheroids after 4h and the spheroids grew to about 200microm after 24h. We examined the expression of cell adhesion molecules in order to clarify the mechanism of aggregate formation. The N-cadherin (N-cad) and Connexin43 (Cx43) expression level of rOB cells cultured with SHya remarkably increased after 2h. A difference in the expression of Integrin beta1 (Intbeta1) could not be observed between the SHya addition and control group. The alkaline phosphatase (ALPase) activity of rOB cells cultured with SHya after 8h was significantly enhanced in comparison with control. Therefore, the sulfate group of SHya seems to enhance expression of cell adhesion protein such as N-cad and Cx43, resulting in aggregate formation and further remarkable induction of the ALPase activity of rOB cells.

Synthesis and characterisation of dextran and pullulan sulphate

Dextrans and pullulans of different molar masses in the range of 10(4)-10(5) g/mol were sulphated via a SO3-pyridine complex. The degree of substitution achieved was DS = 2.4 and DS = 1.4 for dextran sulphate and DS = 2.0 and DS = 1.4 for pullulan sulphate, respectively. Confirmation of sulphation was given by FTIR spectroscopy. Asymmetrical S=O and symmetrical C-O-S stretching vibrations were detected at 1260 and 820 cm(-1). Reactivity of the polysaccharide C-atoms was determined by 13C NMR spectroscopy: For dextran this was C-3 > C-2 > C-4, while for pullulan it was C-6 > C-3 > C-2 > C-4.