Re: anti-malarial antibodiesGabriel, We routinely use DRAQ5, a DNA stain that is sold by Biostatus (www.biostatus.com). It's rapidly taken in by living cells (5 min at room temperature) and binds to DNA stoichiometrically. We use it at concentration of 10 mM final. You should be able to stain the RBCs, fix them at source with formaldehyde and then ship them. We get good correlation between microscopy parasitemia and flow. The staining is however not reliable for parasitemias less than 1%. John Waitumbi ----- Original Message ----- From: Gabriel Alespeiti To: Cytometry Mailing List Sent: Thursday, July 25, 2002 10:12 PM Subject: Re: anti-malarial antibodies Dear colleagues, I have read the replies on anti-malarial antibodies and I hope to get some help from the experts in this field. A researcher in the Institute is conducting parasitaemia studies of Plasmodium falciparum infected erythrocytes using Giemsa stained microscopy, a tedious, time consuming and technically imprecise method. We want to replace the microscopic counts with a flow cytometry method. Peripheral blood will be collected in Brazil and will need to be fixed before shipping. A FACScalibur is available for this work. We would like to analyze 25 samples a day, the expected parasitemia level is between 0.05% and 8%. I tried formaldehyde fixation followed by propidium iodide staining and even though there is a direct correlation between cytometric and microscopic determination, the manual counts are significantly higher than the flow counts. What I'm looking for is a simple, proven protocol for daily use that gives directly the % of parasitaemia by flow. In our case, determination of erythrocyte or parasite antigens; even though useful, is not necessary. What is important for us is to be able to detect low infection levels. Does anybody know, what is the lowest level of infection that can be detected by flow? Please post the reply on this site, so other people can benefit from it. Thank you very much. -- ************************************** Gabriel E. Alespeiti Supervisor, Flow Cytometry Lindsley F. Kimball Research Institute New York Blood Center 310 E.67th St. Room 2-16E New York, NY 10021 Phone: (212) 570-3346 Fax: (212) 570-3307 E-mail:gabriel_alespeiti@nybc.org **************************************
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