Publications by authors named "R K Zwerner"

Flow cytometry, the method of choice for determining subset cell populations, requires sophisticated instrumentation and highly trained operators. An alternative method for subpopulation determinations is presented that is fast, simple, and readily interpreted for absolute subset counts. This method uses antibody labeled microspheres added to whole blood and after lysing, read on a hemocytometer using an ordinary light microscope.

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A method is presented in which specific cells can be rapidly separated from whole blood by the use of antibody labelled dense particles utilizing gravity as a means of separation. This method specifically removes the targeted cells with minimal non-specific cell loss. The method is simple to perform and rapid, requiring less than 10 min for cell/particle binding and separation.

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Anti-CD4 antibody (T4)-coated microspheres were used to label CD4 cells in whole blood. The mixture was lysed and analyzed by a modified Coulter VCS hematology analyzer, which differentiated microsphere-labeled cells by a change in Coulter volume, conductance, and light scatter. %CD3+/CD4+ fluorescent values from a profile were compared to %CD4 values using the VCS-microsphere method.

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We compared the performance of a rapid and simple anti-CD4 antibody-coated microsphere assay with flow cytometry and immunofluorescence for quantitation of absolute count of CD4+ T lymphocytes. A longitudinal evaluation of CD4+ T lymphocytes by flow cytometry and microsphere assay in 10 human immunodeficiency virus (HIV)-seronegative and 59 HIV-seropositive individuals was conducted over a period of 9 months. Standard flow cytometry analysis was performed to establish the absolute CD4+ T-lymphocyte count.

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Objective: To evaluate a manual method (Cytosphere) for quantifying CD4+ T-cell numbers.

Design: Cross-sectional study of HIV-1-seronegative and HIV-1-seropositive individuals evaluated for absolute CD4 counts by both standardized flow cytometric measurements and manual Cytosphere technology using a hemacytometer.

Setting: University research hospitals in both the United States and Africa.

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