I have had the same problems with several of my clients over the years and feel as you do that you can't validate the experiment without proper negative controls. Even though they have been doing the same experiments for years, there is still individual variation among animals and reagent lots. We even see variation among the same reagent lots that have been alloquated and stored in a liquid nitrogen freezer for different periods of time. The best thing you can do is tell the students what you feel is necessary for the proper interpretation of the data and let the instructor worry about explaining why he thinks negative controls aren't necessary. Tell him you need negative controls for the apoptosis experiment because there are changes which occur over time with the alignment of the laser and variables in machine pressure which necessitate these controls for you to set up the machine properly. Most of my clients don't know enough about the workings of my machines to question me and just prepare negative controls when I specifically ask them to. I still have one client who doesn't do negative controls but they run their own experiments on the machines and when they have problems, I just remind them that there will always be unexplained variables since there are no negative controls. hope this helps Janet Dow > I have a client who is teaching an undergraduate immunology class this >fall. He approached me about including Flow Cytometry. I was thrilled to >help and introduce a new batch of potential scientists to Flow Cytometry. >Week number one the class came to the lab to get an overview of Flow >Cytometry. This week they were doing an experiment which involved single >and double staining of spleen and thymocytes. When the samples arrived I >was pretty surprised. My client, their instructor, had not done any >negative controls of any kind. No Igg controls, no unstained cells, >nothing. When I approached him about it he did not seem to think it was a >problem, after all he has done this staining for years. > I am curious what this listserve has to think about this. Am I >being over >vigil about the need to include negative controls in the education process. > As far as I am concerned, there is no way to validate this experiment to >the students. Flow cytometery is what I spend my working day on and it >irks me to no end to see it presented incorrectly. Am I correct to >consider this presentation of Flow incorrect? Am I getting caught up on >philosophical issues and missing the point here? > The lab is coming back again next week to learn about apoptosis. I >don't >want to open a can of worms if it isn't warranted. > Thanks in advance for all feedback. > Joan K > > > > Flow Cytometry Lab Supervisor > VMRCVM > (540) 231-4115 > FAX 540-231-7367 > jkalnits@vt.edu > > "It is better to serve than to receive." > B. Borg Janet Dow Research Technician and Manager Flow Cytometry Facility North Carolina State College of Veterinary Medicine Room C-314 Raleigh, NC 27606 (919)513-6364
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