The Experts below are selected from a list of 213 Experts worldwide ranked by ideXlab platform
Charles D. Forbes - One of the best experts on this subject based on the ideXlab platform.
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Dipyridamole increases human red blood Cell Deformability
European Journal of Clinical Pharmacology, 1992Co-Authors: A R Saniabadi, T C Fisher, J Belch, J Taylor, A. B. Bridges, Charles D. ForbesAbstract:An automated filtration technique has been used to investigate the effect of dipyridamole (DP) on red blood Cell Deformability in patients identified as having rigid red Cells. They were patients on haemodialysis (HD) for chronic renal failure (n=18), patients with peripheral vascular disease (PVD, n=23) and controls (hospital out-patients, n=33). Leucocytes and platelets were removed from heparinised blood by filtration through Imugard wool. Washed red Cell suspensions in buffer at 5% haematocrit, without or with 5 μM DP, were filtered through Nuclepore Hemafil Membranes with 4.7 μm pores. The initial steady state relative filtration pressure (iRFP) was used to assess Cell Deformability. A low iRFP value reflects increased Deformability and vice versa. The mean iRFP values were 0.33, 0.393 and 0.403 for controls, PVD and HD patients respectively, indicating that the red Cells in the two groups of patients were significantly more rigid. DP reduced the iRFP to 0.266, 0.278 and 0.263 for controls, PVD and HD patients respectively.
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Dipyridamole Increases Human Red-Blood-Cell Deformability
European Journal of Clinical Pharmacology, 1992Co-Authors: A R Saniabadi, T C Fisher, A Bridges, J Belch, C. S. Lau, J Taylor, Charles D. ForbesAbstract:An automated filtration technique has been used to investigate the effect of dipyridamole (DP) on red blood Cell Deformability in patients identified as having rigid red Cells. They were patients on haemodialysis (HD) for chronic renal failure (n = 18), patients with peripheral vascular disease (PVD, n = 23) and controls (hospital out-patients, n = 33). Leucocytes and platelets were removed from heparinised blood by filtration through Imugard wool. Washed red Cell suspensions in buffer at 5% haematocrit, without or with 5-mu-M DP, were filtered through Nuclepore Hemafil Membranes with 4.7-mu-m pores. The initial steady state relative filtration pressure (iRFP) was used to assess Cell Deformability. A low iRFP value reflects increased Deformability and vice versa. The mean iRFP values were 0.33, 0.393 and 0.403 for controls, PVD and HD patients respectively, indicating that the red Cells in the two groups of patients were significantly more rigid. DP reduced the iRFP to 0.266, 0.278 and 0.263 for controls, PVD and HD patients respectively. The results suggest that DP may be beneficial when red Cell rigidity contributes to impaired microvascular perfusion.
Makoto Kaneko - One of the best experts on this subject based on the ideXlab platform.
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Novel microfluidic chip for extracting Cell Deformability
2015 IEEE International Conference on Mechatronics and Automation (ICMA), 2015Co-Authors: Chia-hung Dylan Tsai, Makoto Kaneko, Shinya Sakuma, Kouji Mizoue, Fumihito AraiAbstract:A novel microfluidic design is proposed for extracting Cell Deformability under a stable local pressure. In conventional approaches, Cell Deformability is evaluated based on Cell's velocity through a constriction channel where the Cell is deformed due to geometrical constraints. A stiff Cell would move slower due to a greater resistance generated from the deformation. The pressure driving the flow inside the microfluidic system is assumed constant everywhere all the time. However, the assumption is not exactly true since instant change of flow resistance happens while a Cell passing through the constriction. Such pressure change could affect the evaluation results, and should be suppressed as much as possible. In this work, we firstly investigate how such Cell appearance affecting the local flow resistance and pressure change with theoretical modeling. After that, we proposed and fabricated a new microfluidic design to overcome such pressure variation. Two parallel channels are placed above and below the constriction channel, and the purpose is to reduce the resistance change due to Cell appearance inside the constriction. Human red blood Cells are tested, and the results give that the absolute correlation between Cell size and velocity significantly improved from 0.42 to 0.63. The increased correlation physically makes sense because greater deformation causes a greater resistance which lowers Cell velocity more. Therefore, the experimental results show that the proposed design effectively improves the Cell evaluation from conventional approaches.
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URAI - Evaluation of Cell Deformability through micro fluidic channel
2014 11th International Conference on Ubiquitous Robots and Ambient Intelligence (URAI), 2014Co-Authors: Makoto KanekoAbstract:"A fair measurement is possible only under one unknown", which is an iron principle in instrumentation technology. In other words, it is difficult to evaluate two unknowns simultaneously, through the measurement of just one output from sensor. The main topic is to evaluate Cell Deformability through a micro fluidic channel. When a Cell passes through a micro channel whose size is a bit smaller than that of Cell, the passing time (or speed) strongly depends on the stiffness, the viscosity, and the size of Cell. For evaluation of Cell Deformability, there are two approaches; one is the passive approach where each Cell is pushed in the channel under constant pressure, and the other is the active approach where each Cell is actively controlled by an actuator. As for the active approach, we developed a new actuator for controlling a Cell in micro channel with the resolution of 240 [nanometer] and applied for Cell stress test, which is a new Cell Deformability test. This paper explains the outline of our recent works.
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Evaluation of Cell Deformability through micro fluidic channel
2014 11th International Conference on Ubiquitous Robots and Ambient Intelligence (URAI), 2014Co-Authors: Makoto KanekoAbstract:"A fair measurement is possible only under one unknown", which is an iron principle in instrumentation technology. In other words, it is difficult to evaluate two unknowns simultaneously, through the measurement of just one output from sensor. The main topic is to evaluate Cell Deformability through a micro fluidic channel. When a Cell passes through a micro channel whose size is a bit smaller than that of Cell, the passing time (or speed) strongly depends on the stiffness, the viscosity, and the size of Cell. For evaluation of Cell Deformability, there are two approaches; one is the passive approach where each Cell is pushed in the channel under constant pressure, and the other is the active approach where each Cell is actively controlled by an actuator. As for the active approach, we developed a new actuator for controlling a Cell in micro channel with the resolution of 240 [nanometer] and applied for Cell stress test, which is a new Cell Deformability test. This paper explains the outline of our recent works.
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Normalization of flow-in velocity for improving the evaluation on Cell Deformability
2013 IEEE International Conference on Mechatronics and Automation, 2013Co-Authors: Chia-hung Dylan Tsai, Shinya Sakuma, Fumihito Arai, Makoto KanekoAbstract:A method for improving the evaluation of Cell Deformability is proposed. Cell Deformability can be evaluated by the ratio between the Cell velocities before and after entering the narrow throat of a microchannel. However, the flow-in velocity, the Cell velocity before entering the throat, varies with respect to the location of the Cell because of the laminar flow inside the microchannel. To compensate such velocity variation caused by different locations, we obtain a mean velocity by normalizing the velocity profile, and utilize this mean velocity for evaluating Cell Deformability. Experimental study on human red blood Cells is performed. By implementing a high-speed vision system, we acquire the information of the location and velocity of every single Cell through the narrow throat. The acquired data are processed by the proposed method. We compare both the results with and without the normalization, and find that the the proposed method effectively improve the consistency and accuracy of the evaluation.
A R Saniabadi - One of the best experts on this subject based on the ideXlab platform.
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Dipyridamole increases human red blood Cell Deformability
European Journal of Clinical Pharmacology, 1992Co-Authors: A R Saniabadi, T C Fisher, J Belch, J Taylor, A. B. Bridges, Charles D. ForbesAbstract:An automated filtration technique has been used to investigate the effect of dipyridamole (DP) on red blood Cell Deformability in patients identified as having rigid red Cells. They were patients on haemodialysis (HD) for chronic renal failure (n=18), patients with peripheral vascular disease (PVD, n=23) and controls (hospital out-patients, n=33). Leucocytes and platelets were removed from heparinised blood by filtration through Imugard wool. Washed red Cell suspensions in buffer at 5% haematocrit, without or with 5 μM DP, were filtered through Nuclepore Hemafil Membranes with 4.7 μm pores. The initial steady state relative filtration pressure (iRFP) was used to assess Cell Deformability. A low iRFP value reflects increased Deformability and vice versa. The mean iRFP values were 0.33, 0.393 and 0.403 for controls, PVD and HD patients respectively, indicating that the red Cells in the two groups of patients were significantly more rigid. DP reduced the iRFP to 0.266, 0.278 and 0.263 for controls, PVD and HD patients respectively.
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Dipyridamole Increases Human Red-Blood-Cell Deformability
European Journal of Clinical Pharmacology, 1992Co-Authors: A R Saniabadi, T C Fisher, A Bridges, J Belch, C. S. Lau, J Taylor, Charles D. ForbesAbstract:An automated filtration technique has been used to investigate the effect of dipyridamole (DP) on red blood Cell Deformability in patients identified as having rigid red Cells. They were patients on haemodialysis (HD) for chronic renal failure (n = 18), patients with peripheral vascular disease (PVD, n = 23) and controls (hospital out-patients, n = 33). Leucocytes and platelets were removed from heparinised blood by filtration through Imugard wool. Washed red Cell suspensions in buffer at 5% haematocrit, without or with 5-mu-M DP, were filtered through Nuclepore Hemafil Membranes with 4.7-mu-m pores. The initial steady state relative filtration pressure (iRFP) was used to assess Cell Deformability. A low iRFP value reflects increased Deformability and vice versa. The mean iRFP values were 0.33, 0.393 and 0.403 for controls, PVD and HD patients respectively, indicating that the red Cells in the two groups of patients were significantly more rigid. DP reduced the iRFP to 0.266, 0.278 and 0.263 for controls, PVD and HD patients respectively. The results suggest that DP may be beneficial when red Cell rigidity contributes to impaired microvascular perfusion.
M Musielak - One of the best experts on this subject based on the ideXlab platform.
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red blood Cell Deformability measurement review of techniques
Clinical Hemorheology and Microcirculation, 2009Co-Authors: M MusielakAbstract:Abstract Cell-Deformability characterization involves general measurement of highly complex relationships between Cell biology and physical forces to which the Cell is subjected. The review takes account of the modern technical solutions simulating the action of the force applied to the red blood Cell in macro- and microcirculation. Diffraction ektacytometers and rheoscopes measure the mean Deformability value for the total red blood Cell population investigated and the deformation distribution index of individual Cells, respectively. Deformation assays of a whole single Cell are possible by means of optical tweezers. The single Cell-measuring setups for micropipette aspiration and atomic force microscopy allow conducting a selective investigation of deformation parameters (e.g., cytoplasm viscosity, viscoelastic membrane properties). The distinction between instrument sensitivity to various RBC-rheological features as well as the influence of temperature on measurement are discussed. The reports quoted confront fascinating possibilities of the techniques with their medical applications since the RBC-Deformability has the key position in the etiology of a wide range of conditions.
Chen Wang - One of the best experts on this subject based on the ideXlab platform.
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electrical measurement of red blood Cell Deformability on a microfluidic device
Lab on a Chip, 2013Co-Authors: Yi Zheng, John Nguyen, Chen WangAbstract:This paper describes a microfluidic system and a technique for electrically measuring the Deformability of red blood Cells (RBCs). RBCs are deformed when they flow through a small capillary (microfluidic channel). The microfluidic device consists of two stages of microchannels as two measurement units for measuring Cell size/volume and Cell Deformability. A low frequency voltage signal is established across the microfluidic channel, and electrical current signal is sampled continuously when RBCs pass through the measurement areas. Mechanical opacity is defined to mitigate the coupled effect of Cell size/volume and Deformability. The system performed tests on controlled, glutaraldehyde-treated, and heated RBCs using a number of driving pressures. The experimental results proved the capability of the system for distinguishing different RBC populations based on their Deformability with a throughput of ∼10 Cells s−1.