I am curious if you received any response to your questions concerning H2DCFDA and CM-H2DCFDA. We have been using H2DCFDA in both human and murine cell lines to detect ROS. One of the chemicals used to pretreat the cells is dissolved in DMSO and we have also noticed an increase in fluorescence due to increases in DMSO concentration. Our problem has been the high amount of variability in fluorescence intensity (some cells very fluorescent, others with no fluorescence). Does anyone have any suggestions as to how to deal with this variability? We are trying to measure increases in ROS in response to the chemical treatment. We have a Bio-rad MRC1024 with an upright Nikon optiphot. Thanks in advance for any help or suggestions. Susan Garfield Laboratory of Experimental Carcinogenesis Division of Basic Sciences National Cancer Institute, NIH Building 37, Room 3C28 37 Convent Drive MSC4255 Bethesda, MD 20892-4255 Phone: 301-496-5688; Fax: 301-496-0734 -----Original Message----- From: coralia medeiros [SMTP:[log in to unmask]] Sent: Wednesday, September 16, 1998 4:34 PM To: [log in to unmask] Subject: ROS detection This message uses a character set that is not supported by the Internet Service. To view the original message content, open the attached message. If the text doesn't display correctly, save the attachment to disk, and then open it using a viewer that can display the original character set. << File: message.txt >>