Biomedical subjects

R Zwerner

Publications and source records attributed to R Zwerner.

4 recordsLinked to original sources

PubMed1995

Lymphocyte subset determination using a hematology analyzer.

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. CD3 gating was used to exclude CD4+ monocytes from the 90LS-FALS lymphocyte gate. The results correlated well (R = 0.996). The percentage of CD4+ lymphocytes from profile scatterplots and VCS scatterplots showed a line of regression close to the equivalence line (n = 76, slope = 0.96) when CD3 gating was used for the profile. These results suggest that CD3 gating, though necessary for 90LS-FALS scatterplots, may not be necessary for volume-conductance-light scatterplots.

Antibody Specificity↗

PubMed1994

A rapid and reliable assay to enumerate CD4+ T lymphocytes in whole blood.

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. The microsphere assay uses whole blood; CD14+ and CD4+ cells are first blocked by small latex beads coated with anti-CD14 antibody, and remaining cells are stained with larger anti-CD4 antibody-coated beads. Cells rosetted with only anti-CD4 antibody-coated beads are counted with use of a hemacytometer. Immunofluorescence microscopy was performed by standard techniques with use of peripheral blood mononuclear cells. The predictive value for stratification of HIV-seropositive patients by CD4+ T-lymphocyte values of < 200/microliters was 95% when the microsphere method was compared with flow cytometry. A correlation coefficient of 0.91 between the two assay methods was demonstrated in 281 CD4+ T-lymphocyte tests for absolute count. Finally, the flow cytometry method yielded better results than did the microsphere assay and immunofluorescence microscopy, in descending order of accuracy. The microsphere method should be effective in determining absolute CD4+ T-lymphocyte count in developing countries where, for a variety of reasons, no other method can be reliably performed.

CD4 Lymphocyte Count↗

PubMed1993

A rapid manual method for CD4+ T-cell quantitation for use in developing countries.

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. PATIENTS, PARTICIPANTS: Blood specimens from 382 patients were evaluated. These were broken down into 294 samples obtained from HIV-1-seropositive patients and 88 samples obtained from HIV-1-seronegative patients. INTERVENTIONS: None. OUTCOME MEASURED: Absolute CD4 cell number. RESULTS: Evaluation of samples obtained from HIV-1 patients in both the United States and Africa demonstrated an overall correlation of the Cytosphere assay with flow cytometry of 0.912 (95% confidence interval, 0.895-0.928; P < 0.001). When samples were stratified based on CD4+ T-cell counts determined by flow cytometry, the Cytosphere assay had a 96% predictive value for correctly identifying individuals with CD4 T-cell counts > 200 x 10(6)/l and a 92% predictive value for correctly identifying individuals with CD4 T-cell counts < 200 x 10(6)/l. CONCLUSIONS: This assay appears to have the potential for the quantitation of CD4 cells in the limited laboratory facilities in developing countries and to have a strong correlation with standard flow cytometric technology.

Adult↗

PubMed1982

Molecular comparison of mouse Thy-1 and its human homologue.

Physicochemical techniques were used to verify previous immunochemical studies showing homology of the human Thy-1 (formerly p25) antigen and the murine Thy-1 or theta antigen. Peptide maps and amino acid compositions showed close similarity between these two proteins; however, they were not identical. These data confirm that the p25 antigen is the human homologue of mouse Thy-1.

Alanine↗