Flow cytometric probes of early events in cell activation

Abstract

By now, it's well established that the surface of a cell Contains transmembrane proteins which, on binding ligands, tell The biochemical computer inside what to do Without a need for any of the ligands coming through. Receptor‐triggered cytoplasmic “interrupt routines” May lead the nucleus to activate new sets of genes, Or otherwise induce a cell, which never reasons why, To twitch, secrete, endocytose, or reproduce, or die. By merely watching labeled ligands bind, we cannot know Down which of many paths the cells thus tagged are apt to go, But other changes, shortly after binding, may predict Which of its several options any given cell has picked. Flow cytometric methods are described here which allow Membrane potential to be estimated, to show how Potential changes may occur in seconds after binding Of ligand to a functional receptor, or for finding No change when cells don't have the right receptor, or can't see The ligand for antagonists of like affinity. With chlorotetracycline fluorescence, one can find Release of membrane calcium soon after ligands bind; Both this and the potential measurement can help support Decisions in an instrument about which cells to sort, Though narrowing the distributions which these methods yield Would greatly help to broaden applications in this field.

Physiological and morphological correlates of among-individual variation in standard metabolic rate in the leopard frog Rana pipiens

“…Finally, we re-suspended the cells in 1·ml HBSS for fluorescence analysis. We acquired fluorescence emission intensity of 20·000 total counts (a count is any particle, such as a cell, that the flow cytometer detects) at 663·nm with a FACSCaliber flow cytometer (BD Bioscience, San Jose, CA; Johnson et al, 1980;Shapiro, 1981).…”

“…In a novel approach, we examine two potential proximate correlates of variation in SMR, in addition to organ mass, in leopard frogs Rana pipiens. We measured SMR of the frogs, then measured the masses of energetically expensive organs, serum-free T4 thyroxine, and relative mitochondrial content using flow cytometry (Johnson et al, 1980;Shapiro, 1981). We asked three questions: first, how much amongindividual variation exists in the metabolic rate of an amphibian?…”

Flow cytometric detection of membrane potential changes in murine lymphocytes induced by concanavalin A

“…Thus dye uptake by the cells is sensed indirectly by observing a fall in suspension emission. However, when cell fluorescences are measured individually by flow cytometry, there is no contribution from extracellular dye and it is therefore possible to detect cell uptake or release directly (Shapiro, 1981). In these circumstances it is undesirable to use a high concentration of dye, because 'saturation' of cell fluorescence would impede the detection of changes in cell dye content.…”

Multivariate analysis and list mode processing of murine hemopoietic subpopulations for cytokinetic studies

“…A review of the fluorescent characteristics of nels 120-140) than did those comprised of more mature the cyanine dyes and selected applications in flow cytom-elements (areas 1 and 3). In addition, it is interesting to etry can be found in Shapiro et al (20)(21)(22) and Jacobber-note that the coefficient of variation ranges from 2.5 to ger (9,lO). Recently, Cohen et al (3) reported that the 5.0, and the mean channel number of the G1 peak also fluorescence intensity of fibroblasts exposed to cyanine varies from 97 to 101 between subpopulations, suggestwas dependent upon their cycling status.…”