Analysis of factors regulating erythrocyte deformability.

Mohandas, Narla; Clark, Margaret; Jacobs, Mark S.; Shohet, Stephen B.

doi:10.1172/jci109888

Cited by 345 publications

(229 citation statements)

References 21 publications

Supporting

Mentioning

211

Contrasting

Unclassified

Order By: Relevance

“…Such data are often plotted versus the shear stress of the undisturbed shear flow ðs ¼ g 0 _ cÞ suggesting that EI scales with s. If, on the other hand, the same blood sample was tested varying both g 0 and _ c, it was shown that EI does not scale with s. Using four viscosities between 12 and 51 mPas, EI was found to scale with g 1:5 0 _ c (3). An exponent greater unity can also be inferred from other experimental results (4,5).…”

supporting

confidence: 60%

Effects of shear rate and suspending medium viscosity on elongation of red cells tank‐treading in shear flow

Fischer

Korzeniewski

2011

Cytometry Pt A

View full text Add to dashboard Cite

Elongation measurements of red cells subjected to simple shear flow are usually performed using a single suspending medium (viscosity g 0 ) and varying the mean shear rate ð _ cÞ. Such data are often plotted versus the shear stress ðs ¼ g 0 _ cÞ suggesting that the elongation scales with s. In this work, normal blood samples were tested in a rheoscope varying both g 0 and _ c. The ranges of _ c were chosen to restrict the elongation of the red cells to low values where the behavior is dominated by their intrinsic properties. It was found that the elongation scales with g s 0 _ c with s decreasing from two at g 0 5 20 mPas to unity at g 0 5 70 mPas. Above g 0 5 70 mPas, the elongation is therefore essentially determined by the membrane elasticity alone. A side observation was a large variation of the elongation both intraindividually and interindividually. ' International Society for Advancement of CytometryKey terms rheoscope; image processing; computer modeling; scaling behavior; shape distributions; share of cell viscosities A standard method to measure the mechanical properties of red cells is to suspend the cells in solutions much more viscous than blood plasma and to measure their elongation when the suspension is subjected to simple shear flow (1,2). In addition to being elongated, the membrane moves around the elongated shape thus inducing an eddy flow within the cytoplasm. The membrane motion has been termed tanktread motion (1). The elongation is usually quantified by an elongation index EI ¼ LÀB LþB , where L and B denote the length and the width of the elongated cell. Measurements of EI of different blood samples are usually performed using a constant viscosity of the suspending medium (g 0 ) under variation of the mean shear rate ð _ cÞ. Such data are often plotted versus the shear stress of the undisturbed shear flow ðs ¼ g 0 _ cÞ suggesting that EI scales with s. If, on the other hand, the same blood sample was tested varying both g 0 and _ c, it was shown that EI does not scale with s. Using four viscosities between 12 and 51 mPas, EI was found to scale with g 1:5 0 _ c (3). An exponent greater unity can also be inferred from other experimental results (4,5).To explain this finding, the following hypothesis is put forward. (i) Besides elastic stresses, viscous stresses resist an elongation of tank-treading red cells. (ii) A variable contribution of the viscous stresses being three dimensional in the cytoplasm and two dimensional in the membrane is responsible for an exponent greater unity.To rationalize the hypothesis, we consider the following experiment. We first measure EI with a certain set of _ c and g 0 . Then we decrease _ c by a certain amount and increase g 0 to such an extent that EI remains constant. The elastic stresses and bending moments in the membrane remain essentially constant as EI did not change.

show abstract

supporting

confidence: 60%

Effects of shear rate and suspending medium viscosity on elongation of red cells tank‐treading in shear flow

Fischer

Korzeniewski

2011

Cytometry Pt A

View full text Add to dashboard Cite

show abstract

“…Whole blood was diluted to a final hematocrit (volume fraction of RBCs) of 2 ϫ 10 Ϫ3 l/l in 5.0 ml of a solution of 0.14 mM of PVP (Mw ϭ 360,000; Sigma-Aldrich, St. Louis, MO) in phosphate buffered saline (PBS; pH 7.4). The viscosity of the PVP medium at 37°C was 31 mPa/s, and a physiological osmolality (290 mOsm/ kg) was used to prevent cell shrinkage or swelling (31). Approximately 100 l of the dilute suspension was used for each experiment.…”

Section: Methodsmentioning

confidence: 99%

“…The stiffness of the RBC membrane can be reduced artificially by heat treatment (13,31), typically performed at 48°C. The sensitivity of the rheoscope was tested by using such heattreated RBCs.…”

Section: Methodsmentioning

confidence: 99%

“…During aging, the area of the RBC surface decreases and osmotic gradients drain water from the cell, causing its volume to decrease and its internal viscosity and density to increase. The net effect is decreased deformability (31). This density-deformability (or density-age) dependence was exploited to separate less deformable (high-density) cells from deformable (low-density) cells by centrifugation (7,13).…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Measurement of the distribution of red blood cell deformability using an automated rheoscope

et al. 2002

View full text Add to dashboard Cite

“…The Ektacytometer Index (EI formerly called Deformability Index (DI) (7)) is then defined as: EI = A -B / A + B where A and B are the measured intensities. This quantity may then be directly related to the elongation (L -W/L + W) (9).…”

Section: Methodsmentioning

confidence: 99%

Isovolumetric sphering of erythrocytes for more accurate and precise cell volume measurement by flow cytometry

Kim¹,

Ornstein

1983

Cytometry

103

View full text Add to dashboard Cite

Typical mammalian erythrocytes are biconcave disks. Flow cytometric light-scattering measurements of red cell volume show large, orientation-dependent variations in signal size. To eliminate errors caused by shape factors, we sphere erythrocytes isovolumetrically on an AutoAnalyzer manifold (Technicon Instruments Corp., Tarrytown, N.Y.) using a carefully controlled ratio of concentrations of a salt of long chain sulfated fatty alcohol (e.g., sodium dodecyl sulfate (SDS)) to albumin in neutrally buffered isotonic saline, producing a suspension with at least 2% hours of stability with respect to cell volume, cell count and retention of hemoglobin. A two-step manifold modification of this procedure is preferred. It uses the endogeneous serum protein and a first SDS-saline reagent without added albumin at a low dilution, and further dilution with a second SDS-saline containing a very low concentration of glutaraldehyde. This bypasses a serious shelf life problem with the albumin-SDS reagent.Microhematocrit and Coulter electronic impedance measurements were correlated with light-scattering measurements on our own flow cytometer system of unsphered, sphered, and sphered and fixed samples. These reveal marked superiority over unsphered samples (e.g., reduced coefficients of variation of cell volume and improved correlation with microhematocrit) of the sphered and of the sphered and lightly fixed cells. The resulting tighter unimodal cell volume distributions also provide the following advantages: 1) The separation of signals of large platelets from that of the smallest red cells is substantially increased permitting better resolution of microcytic red cells in some abnormal bloods, and 2) bimodality of red cell volume distribution in abnormal bloods is more easily resolved.

show abstract

Analysis of factors regulating erythrocyte deformability.

Cited by 345 publications

References 21 publications

Effects of shear rate and suspending medium viscosity on elongation of red cells tank‐treading in shear flow

Effects of shear rate and suspending medium viscosity on elongation of red cells tank‐treading in shear flow

Measurement of the distribution of red blood cell deformability using an automated rheoscope

Isovolumetric sphering of erythrocytes for more accurate and precise cell volume measurement by flow cytometry

Contact Info

Product

Resources

About