I developed a flow cytometric method for measuring pinocytosis, which was originally published in Cytometry 7:251-262, 1986 ( how time flies). In those studies, I saw no evidience of quenching due to dextran-FITC concentration in the range of 0.1 - 10 mg/ml. However, the fluorescence is quite sensitive to pH, so you need to be concerned about endosomal acidification and the use of buffered solutions. As for freezing the solution, I never tried, so I can't help you there. Bruce H. Davis, M.D. Dept. of Clinical Pathology William Beaumont Hosp. 3601 W 13 Mile Rd. Royal Oak, MI 48073-6769 USA Phone: 248-551-5137 FAX: 248-551-1262 "Fang-Yao (Stephen) Hou" wrote: > Hi,fellow flow cytometrists: > > I am trying to develop a flow pinocytosis assay using fluorescein dextran > from Molecular Probe (D-1845). This assay will be used to monitor the > antigen uptake by dendritic cells. Does anyone here try similar approach? > Please share with me your sucess. > > Currently, I have two questions in mind. The first one is about the > stability of frozen fluorescein dextran in solution in the event that > we may prepare several stocks and freeze them. The second one is the > concern that too much dextran may end up with lower fluorescence. I saw > this phenomenon once and suspected that either quenching or too much > dextran outside the cells being like a barrier resulted in the lower > fluorescence. I would appreciate your help and would like to see any > references as well. Thanks. > > Fang-Yao (Stephen) Hou > FYHOU@DELPHI.COM > >
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