M. Meakin

University of Birmingham, Birmingham, England, United Kingdom

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Publications (7)4.71 Total impact

  • J Stuart · M W Kenny · M Meakin · G S Lucas · N M Caldwell
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    ABSTRACT: Positive-pressure and initial-flow-rate (Hémorhéomètre) methods for the study of erythrocyte filtration through 5 micron diameter pores are highly sensitive to the presence of contaminating leucocytes in the erythrocyte test suspension. A pre-filtration step, in which heparinised or EDTA-anticoagulated whole-blood was passed through a column of Imugard IG500 cotton wool, was therefore developed. This procedure removed contaminating platelets and leucocytes, but not erythrocyte sub-populations, and is likely to improve the sensitivity and specificity of erythrocyte filtration techniques.
    No preview · Article · Feb 1984 · Biorheology. Supplement: the official journal of the International Society of Biorheology
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    ABSTRACT: Positive-pressure and initial-flow-rate (Hémorhéomètre) filtration systems were used to study the deformability of erythrocytes from whole blood stored in EDTA or heparin. When all contaminating platelets and leucocytes were removed from the erythrocyte suspension there was no significant anticoagulant effect on erythrocyte filtration. Blood may therefore be stored in K2EDTA (1.5 mg/ml blood) or lithium heparin (15 IU/ml blood) for up to 6 hours at room temperature prior to measurement of erythrocyte filterability.
    No preview · Article · Feb 1984 · Biorheology. Supplement: the official journal of the International Society of Biorheology
  • M.W. Kenny · M. Meakin · J. Stuart
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    ABSTRACT: A gravity filtration technique, using cotton wool from an Imugard IG500 filter, has been developed for removal of leucocytes and platelets from EDTA- or heparin-anticoagulated blood prior to studies of erythrocyte deformability. This technique removed 98.1% of leucocytes and 99.8% of platelets, without causing haemolysis, and was found to be superior to alternative methods of cell removal including centrifugation, column sedimentation, and filtration through cellulose. The erythrocytes recovered after filtration through cotton wool were representative of the original blood sample, as judged by cell size distribution, and there was no selective removal of reticulocytes, irreversibly sickled cells, or Heinz-body containing cells.
    No preview · Article · Jan 1983
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    ABSTRACT: Initial-flow-rate (Hémorhéomètre) and positive-pressure filtration systems were used to study the effects of EDTA and heparin on erythrocyte filterability after storage of whole blood for up to 6 hours from venepuncture. Heparin had a time-dependent, adverse effect on filtration through 5 μm diameter pores, causing an increase in platelet microaggregate formation and a decrease in leucocyte filterability. Erythrocyte suspensions from which all contaminating platelets and leucocytes had been removed by prefiltration through Imugard IG500 cotton wool, however, showed no significant alteration in erythrocyte filterability during storage of blood in EDTA or heparin; the filtration values were similar to those of defibrinated blood. Thus, for both initial-flow-rate and positive-pressure studies of erythrocyte filterability, blood may be stored at room temperature in either dipotassium EDTA (1.5 mg/ml blood) or lithium heparin (15 IU/ml blood) for up to 6 hours after venepuncture.
    No preview · Article · Jan 1983
  • G.S. Lucas · N.M. Caldwell · M. Meakin · J. Stuart
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    ABSTRACT: A comparison of filtration methods for the study of erythrocyte deformability has been made using an initial-flow-rate gravity filtration instrument (Hémorhéomètre) and both the initial (Pi) and final (Pf) pressures of positive-pressure filtration systems. Pf was the most sensitive filtration parameter for the detection of either a sub-population of hardened erythrocytes or a more uniform loss of deformability of the bulk cell population. This pilot study provides a basis for evaluation of commercial instruments and demonstrates the potential sensitivity, and improving precision, of positive-pressure systems.
    No preview · Article · Jan 1983
  • M W Kenny · M Meakin · D J Worthington · J Stuart
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    ABSTRACT: A serial study of erythrocyte deformability, plasma viscosity, and whole-blood viscosity has been made during 10 sickle-cell vaso-occlusive crises. The peak serum lactate dehydrogenase level was used to confirm the duration of crisis and the rheological changes were compared with 19 estimations made on the same patients when asymptomatic. Erythrocyte deformability, measured by filtration of washed erythrocytes through polycarbonate filters of 5 microgram pore size, was significantly reduced on day 1 of crisis and, in one additional patient, this occurred 24 h before the onset of pain. There was no increase in irreversibly-sick-led-cell counts and plasma- and blood-viscosity did not increase significantly until day 5 of crisis, in parallel with the acute-phase rise in plasma fibrinogen. Measurement of erythrocyte filterability is therefore a valuable technique for investigating the pathogenesis of the early stages of sickle-cell crisis.
    No preview · Article · Oct 1981 · British Journal of Haematology
  • M.W. Kenny · M. Meakin · J. Stuart
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    ABSTRACT: A positive-pressure, washed-erythrocyte method for the measurement of red cell filterability has been compared with a negative-pressure, whole-blood technique. Using 5 μm pore-size polycarbonate filters, both methods detected a sub-population of 4-5 x 107/1 glutaraldehyde-hardened erythrocytes and both showed a decrease in erythrocyte filterability in proportion to increasing concentrations of added fibrinogen. The washed-erythrocyte method gave better reproducibility with less variation between filter batches and is recommended for the study of patients in whom plasma hyperproteinaemia may adversely affect erythrocyte filtration.
    No preview · Article · Jan 1981