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Biomedical subjects

R Raynor

Publications and source records attributed to R Raynor.

5 recordsLinked to original sources
PubMed2001

An interlaboratory study of a candidate reference method for platelet counting.

A multinational interlaboratory task force explored the important variables of platelet reference counting and developed a candidate flow cytometric reference method based on the RBC/platelet ratio. A multicenter comparison was performed to determine whether the method met the necessary criteria and was precise enough to be recommended as a new reference method. Each laboratory analyzed serial dilutions of normal specimens, stabilized material, and at least 60 patient specimens with a range of platelet counts from 1 to 400 x 10(3)/microL (1-400 x 10(9)/L). Pooled analysis of the serial dilutions showed that RBC-platelet and RBC-RBC coincidence events became negligible at sufficiently high dilutions (i.e., > 1:1,000). All laboratories demonstrated excellent intra-assay and acceptable interlaboratory precision. Two antibodies (CD61 and CD41) were used for identifying platelets and individually gave acceptable results, but in a minority of samples, staining differences were observed. The optimum method thus uses a double-labeling procedure with a final dilution factor of 1:1,000. The study demonstrated that this method meets the criteria for a reference platelet count.

Anticoagulants↗
PubMed1993

Whole blood method for simultaneous detection of surface and cytoplasmic antigens by flow cytometry.

Dual parameter analysis of surface antigens in flow cytometry has become a standard method for detection of cell subsets. However, few methods have been described for the extension of multiparameter analyses to include cytoplasmic or intracellular antigens. Here we describe a simple and reproducible method for simultaneous detection of surface and intracellular antigens by flow cytometry in lysed whole blood samples. This method employs the use of digitonin, a mild glycoside detergent, and formaldehyde for permeabilization and fixation. Red blood cells are lysed with 2% acetic acid. Preparation of samples in this manner resulted in altered light scatter characteristics relative to unpermeabilized samples; however, gating issues were overcome using a combination of scatter vs. fluorescence gating. Quantitation of CD3+/CD4+ and CD3+/CD8+ cells using this method was equivalent to counts obtained with the reference method using a commercially available lysis procedure and fluorescence vs. scatter gating. The effectiveness of the permeabilization process was assessed using a monoclonal antibody designated TIA-1, which is specific for a cytoplasmic antigen associated with cytotoxic granules predominantly found in CD8+ cells. The method effectively quantitated TIA-1 positive cells and demonstrated the specificity of the reagent for a subpopulation of CD8+ lymphocytes. Using this simplified procedure for simultaneous identification of surface and cytoplasmic antigens could help in studies of cell activation, proliferation, and other functional characteristics of the immune system.

Antibodies, Monoclonal↗
PubMed1993

Structure-function relationships of alkyl-lysophospholipid analogs in selective antitumor activity.

This investigation was initiated in order to delineate the structure-function relationship of the anticancer alkyl-lysophospholipids and assess their degree of selective cytotoxicity toward neoplastic cells. A series of glycerol phosphocholine analogs with varying substitutions in the sn-1 and sn-2 position were tested for their inhibitory activity as measured by thymidine incorporation, clonogenic assays and effects on protein kinase C activity against a series of human leukemic cell lines and healthy bone marrow progenitor cells. The IC50 was determined for each of the compounds in each cell line and healthy bone marrow cells following a 4-h incubation. The data indicated that a 16-18 carbon chain at the sn-1 coupled with a short substitution at sn-2 had the broadest antitumor activity and was the least toxic to normal bone marrow cells. The results provide a number of useful leads toward the design and development of potentially more active phospholipid compounds.

Antineoplastic Agents↗