I might suggest that you try using SYBR Green II from Mol Probes. I investigated this label while investigating variants of the rodent micronucleus assay. It was not suitable because it was too bright! This was with ethanol fixed, RNAse treated mouse erythrocytes. It was quite easy to identify rbc populations with 1 through 4 parasites each. As we used the malaria as a DNA size standard for identifying micronuclei, we had no interest in comparing our signals to viable parasite levels. See the paper Dertinger SD, Torous DK, Tometsko KR. Simple and reliable enumeration of micronucleated reticulocytes with a single-laser flow cytometer. Mutat Res. 1996 Dec 20;371(3-4):283-92 for the basic method. -Jim Weaver * * * Gabriel Alespeiti wrote- * * >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. *
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