The neuritogenic effect of exogenous ganglioside has been documented with a variety of neuronal and neuroblastoma systems, but the mechanism is not understood. Involvement of Ca2+ is suggested by this study which demonstrates that treatment of Neuro-2A cells with bovine brain gangliosides (BBG) in Ca2(+)-depleted medium failed to produce neurite outgrowth. This was in contrast to treatment with retinoic acid or dibutyryl cyclic AMP which induced differentiation under the same conditions. Addition of BBG to Neuro-2A cells caused small, but significant, increases in both influx and efflux of Ca2+. It thus appears that although neuritogenesis can proceed by more than one mechanism, that induced by BBG requires exogenous Ca2+ and involves stimulation of Ca2+ flux.

In patients with primary sclerosing cholangitis, MR cholangiopancreatography better shows the bile ducts and can depict more strictures, especially of the peripheral intrahepatic ducts, than ERCP. MR cholangiopancreatography can be used to noninvasively diagnose and follow up patients with primary sclerosing cholangitis.

Contrast-enhanced MR cholangiography with IV mangafodipir trisodium can successfully detect the presence and location of bile duct leaks in patients suspected of having such leaks after undergoing cholecystectomy. More research is necessary before acceptance of this examination as routine in the workup of these patients.