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Type: Artigo de periódico
Title: Impaired Elasticity Of Red Blood Cells With Different Membrane Protein Defects Measured By Optical Tweezer Technique
Author: Brandao M.M.
Cesar C.L.
Costa F.F.
Saad S.O.
Abstract: The deformability of erythrocytes is a critical determinant of flow in the microcirculation. This deformability is the combined result of several mechanical and geometrical properties, such as internal viscosity, surface area-volume ratio and membrane elasticity and viscosity. The importance of the erythrocyte membrane organization in maintaining the red cell deformability is well established . Mutations in the red cell membrane proteins, as spectrin, ankyrin and band 3, are commonly observed in hereditary spherocytosis (HS), a hemolytic anemia with reduced surface area-volume ratio and deformability of the erythrocyte. We have studied, by Laser Optical Tweezers based on photon momentum transfer, the red cell elasticity and deformability of 6 patients with hereditary spherocytosis (three band 3, two beta-spectrin and one ankyrin mutation) and 13 normal controls (C). The trap was set with a Nd:YAG laser focused in a microscope and the measurement was obtained by dragging the red blood cell through human AB plasm fluid with a known viscosity. The analysis of the cell deformation vs velocity allowed us to obtain the cell elasticity. At least 10 erythrocytes from each subject were submitted to 6 velocities, varying from 150 to 250 nm/s (150, 170, 190, 210, 230, 250 p.m/ s). HS erythrocytes presented significantly lower elasticity than the normal control cells (C: mean ±SD, 0.00081 ±0.000405 dyn/cm vs. HS: mean ±SD, 0.0030 ±0.005 dyn/cm p=0.008. Student T test). At least 30% of the HS cells presented no deformability during the experiments. We were not able to detect any difference in red blood cell elasticity according to band 3 or spectrin or ankyrin defects (p= 0.62, ANOVA). We conclude that defects affecting the red cell membrane can be detected by the optical tweezer technique.
Rights: fechado
Identifier DOI: 
Date Issue: 2000
Appears in Collections:Unicamp - Artigos e Outros Documentos

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