scholarly journals Measurement of rapid changes in cell volume by forward light scattering

2003 ◽  
Vol 447 (1) ◽  
pp. 97-108 ◽  
Author(s):  
S. P. Srinivas ◽  
Joseph A. Bonanno ◽  
Els Larivi�re ◽  
Danny Jans ◽  
Willy Van Driessche
Keyword(s):  
Light Scattering ◽  
Cell Volume ◽  
Rapid Changes

scholarly journals Two Independent Light Dilution Corrections for the SO2 Camera Retrieve Comparable Emission Rates at Masaya Volcano, Nicaragua

2021 ◽  
Vol 13 (5) ◽  
pp. 935
Author(s):  
Matthew Varnam ◽  
Mike Burton ◽  
Ben Esse ◽  
Giuseppe Salerno ◽  
Ryunosuke Kazahaya ◽  
...  
Keyword(s):  
Light Scattering ◽  
Optical Depth ◽  
Camera Calibration ◽  
Wind Direction ◽  
Emission Rate ◽  
Emission Rates ◽  
Depth Images ◽  
Masaya Volcano ◽  
Rapid Changes ◽  
Volcanic Emission

SO2 cameras are able to measure rapid changes in volcanic emission rate but require accurate calibrations and corrections to convert optical depth images into slant column densities. We conducted a test at Masaya volcano of two SO2 camera calibration approaches, calibration cells and co-located spectrometer, and corrected both calibrations for light dilution, a process caused by light scattering between the plume and camera. We demonstrate an advancement on the image-based correction that allows the retrieval of the scattering efficiency across a 2D area of an SO2 camera image. When appropriately corrected for the dilution, we show that our two calibration approaches produce final calculated emission rates that agree with simultaneously measured traverse flux data and each other but highlight that the observed distribution of gas within the image is different. We demonstrate that traverses and SO2 camera techniques, when used together, generate better plume speed estimates for traverses and improved knowledge of wind direction for the camera, producing more reliable emission rates. We suggest combining traverses and the SO2 camera should be adopted where possible.

scholarly journals Reflection coefficient and permeability of urea and ethylene glycol in the human red cell membrane.

1983 ◽  
Vol 81 (2) ◽  
pp. 239-253 ◽  
Author(s):  
D G Levitt ◽  
H J Mlekoday
Keyword(s):  
Refractive Index ◽  
Light Scattering ◽  
Reflection Coefficient ◽  
Ethylene Glycol ◽  
Cell Volume ◽  
Solute Concentration ◽  
Transport Systems ◽  
Red Cell ◽  
Red Cell Membrane ◽  
Nacl Concentration

The reflection coefficient (sigma) and permeability (P) of urea and ethylene glycol were determined by fitting the equations of Kedem and Katchalsky (1958) to the change in light scattering produced by adding a permeable solute to a red cell suspension. The measurements incorporated three important modifications: (a) the injection artifact was eliminated by using echinocyte cells; (b) the use of an additional adjustable parameter (Km), the effective dissociation constant at the inner side of the membrane; (c) the light scattering is not directly proportional to cell volume (as is usually assumed) because refractive index and scattering properties of the cell depend on the intracellular permeable solute concentration. This necessitates calibrating for known changes in refractive index (by the addition of dextran) and cell volume (by varying the NaCl concentration). The best fit was for sigma = 0.95, Po = 8.3 X 10(-4) cm/s, and Km = 100 mM for urea and sigma = 1.0, Po = 3.9 X 10(-4) cm/s, and Km = 30 mM for ethylene glycol. The effects of the inhibitors copper, phloretin, p-chloromercuriphenylsulfonate, and 5,5'-dithiobis (2-nitro) benzoic acid on the urea, ethylene glycol, and water permeability were determined. The results suggest that there are three separate, independent transport systems: one for water, one for urea and related compounds, and one for ethylene glycol and glycerol.

scholarly journals Measurement of the intramitochondrial volume in hepatocytes without cell disruption and its elevation by hormones and valinomycin

1983 ◽  
Vol 214 (2) ◽  
pp. 395-404 ◽  
Author(s):  
P T Quinlan ◽  
A P Thomas ◽  
A E Armston ◽  
A P Halestrap
Keyword(s):  
Light Scattering ◽  
Cell Volume ◽  
Respiratory Chain ◽  
Mitochondrial Protein ◽  
Liver Cells ◽  
Hormonal Control ◽  
Cell Disruption ◽  
Mitochondrial Volume ◽  
Respiratory Chain Activity ◽  
Stimulation Of

Methods have been developed to measure the lysophospholipid content and matrix volume of liver cell mitochondria in situ in order to test the hypothesis that these parameters may be important in the hormonal control of mitochondrial function [Armston, Halestrap & Scott (1982) Biochim. Biophys. Acta 681, 429-439]. No change in the labelling of mitochondrial lysophospholipids with [32P]Pi was detected after treatment of liver cells with glucagon, phenylephrine or vasopressin. Incorporation of [32P]Pi into mitochondrial phosphatidylinositol was enhanced by phenylephrine and vasopressin. Mitochondrial volumes were measured using rapid disruption of cells by sonication into 3H2O and [14C]sucrose or without cell disruption using 3H2O and [14C]mannitol. In control cells the two methods gave values of 1.09 and 0.40 microliters/mg of mitochondrial protein respectively, which represent 19 and 7% respectively of the total cell volume measured with 3H2O and inulin [14C]carboxylic acid. Both methods showed that glucagon, phenylephrine and 1 nm-valinomycin produced significant increases (13% and 26% using sucrose and mannitol respectively) in mitochondrial volume. The increase was coincident with the stimulation of gluconeogenesis from L-lactate and pyruvate and of mitochondrial respiratory chain activity. The effects of glucagon and phenylephrine were additive on both mitochondrial volume and respiratory chain activity, but not on gluconeogenesis. Liver cells exposed to gluconeogenic hormones or low concentrations of valinomycin showed a decrease in light scattering at 520 nM correlating with the change in mitochondrial volume but without a change in whole-cell volume. The time course and hormone sensitivity of this response were similar to those for the hormonal stimulation of gluconeogenesis. The light-scattering response to glucagon, phenylephrine and vasopressin, but not to valinomycin, were greatly reduced or abolished in Ca2+-free media.

Development of instrumentation and fluorochromes for automated multiparameter analysis of cells.

1977 ◽  
Vol 23 (8) ◽  
pp. 1492-1498 ◽  
Author(s):  
R C Leif ◽  
R A Thomas ◽  
T A Yopp ◽  
B D Watson ◽  
V R Guarino ◽  
...  
Keyword(s):  
Rare Earth ◽  
Light Scattering ◽  
Cell Volume ◽  
Holographic Grating ◽  
Physical Parameters ◽  
Ultraviolet Laser ◽  
Multiparameter Analysis ◽  
Automated Instrument

Abstract We have developed and interfaced to a computer an automated instrument (the AMAC III) which is designed to observe simultaneously several physical parameters of cells. Typical parameters include electronic cell volume (Coulter effect), RF amplitude (opacity), multiwavelength fluorescence of cytological stains, and cell light-scattering. The use of a new ultraviolet laser combined with a holographic grating spectrograph promises to increase the number of fluorescing species that can be detected simultaneously. This number can be further increased by use of special rare-earth-based fluorochromes, that emit well-defined, spectrally distinct peaks.

scholarly journals Accurate and independent measurement of volume and hemoglobin concentration of individual red cells by laser light scattering

Blood ◽  
1986 ◽  
Vol 68 (2) ◽  
pp. 506-513 ◽  
Author(s):  
N Mohandas ◽  
YR Kim ◽  
DH Tycko ◽  
J Orlik ◽  
J Wyatt ◽  
...  
Keyword(s):  
Light Scattering ◽  
Cell Volume ◽  
Concentration Distribution ◽  
Laser Light ◽  
Hemoglobin Concentration ◽  
Laser Light Scattering ◽  
Red Cells ◽  
Red Cell ◽  
Flow Cytometric ◽  
Wide Range

Cell volume (MCV) and hemoglobin concentration (MCHC) are the red cell indices used to characterize the blood of patients with anemia. Since the introduction of flow cytometric methods for the measurement of these indices, it has generally been assumed that the values derived by these instruments are accurate. However, it has recently been shown that a number of cellular factors, including alterations in cellular deformability, can lead to inaccurate measurement of cell volume by these automated instruments. Because cell hemoglobin concentration and hematocrit are computed from the measured values of cell volume, accuracy of these indices is also compromised by inaccurate determination of cell volume. A recently developed experimental flow cytometric method based on laser light scattering, which can independently measure volume and hemoglobin concentration, has been used in the present study to measure MCV and MCHC of density- fractionated normal and sickle red cells, hydrated and dehydrated normal red cells, and various pathologic cells. We found that the new method accurately measures both volume and hemoglobin concentrations over a wide range of MCV (30 to 120 fL) and MCHC (27 to 45 g/dL) values. This is in contrast to currently available methods in which hemoglobin concentration values are accurately measured over a more limited range (27 to 35 g/dL). In addition, as the experimental method independently measures volume and hemoglobin concentration of individual red cells, it allowed us to generate histograms of volume and hemoglobin concentration distribution and derive coefficient of variation for volume distribution and standard deviation of hemoglobin concentration distribution. We have been able to document that volume and hemoglobin concentration distributions can vary independently of each other in pathologic red cell samples.

scholarly journals Large and rapid changes in light scattering accompany secretion by nerve terminals in the mammalian neurohypophysis.

1985 ◽  
Vol 86 (3) ◽  
pp. 395-411 ◽  
Author(s):  
B M Salzberg ◽  
A L Obaid ◽  
H Gainer
Keyword(s):  
Membrane Potential ◽  
Light Scattering ◽  
Secretory Activity ◽  
Peptide Hormones ◽  
Nerve Terminals ◽  
Optical Signals ◽  
Rapid Changes ◽  
Frequency Of Stimulation

Large changes in the opacity of the unstained mouse neurohypophysis follow membrane potential changes known to trigger the release of peptide hormones. These intrinsic optical signals, arising in neurosecretory terminals, reflect variations in light scattering and depend upon both the frequency of stimulation and [Ca2+]o. Their magnitude is decreased in the presence of Ca2+ antagonists and by the replacement of H2O in the medium by D2O. These observations suggest a correspondence between the intrinsic optical changes and secretory activity in these nerve terminals.

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