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Kageyama S, Takeishi N, Taenaka H, Yoshida T, Wada S. Fluid dynamic assessment of positive end-expiratory pressure in a tracheostomy tube connector during respiration. Med Biol Eng Comput 2022; 60:2981-2993. [PMID: 36002620 PMCID: PMC9402408 DOI: 10.1007/s11517-022-02649-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 08/19/2022] [Indexed: 11/24/2022]
Abstract
High-flow oxygen therapy using a tracheostomy tube is a promising clinical approach to reduce the work of breathing in tracheostomized patients. Positive end-expiratory pressure (PEEP) is usually applied during oxygen inflow to improve oxygenation by preventing end-expiratory lung collapse. However, much is still unknown about the geometrical effects of PEEP, especially regarding tracheostomy tube connectors (or adapters). Quantifying the degree of end-expiratory pressure (EEP) that takes patient-specific spirometry into account would be useful in this regard, but no such framework has been established yet. Thus, a platform to assess PEEP under respiration was developed, wherein three-dimensional simulation of airflow in a tracheostomy tube connector is coupled with a lumped lung model. The numerical model successfully reflected the magnitude of EEP measured experimentally using a lung phantom. Numerical simulations were further performed to quantify the effects of geometrical parameters on PEEP, such as inlet angles and rate of stenosis in the connector. Although sharp inlet angles increased the magnitude of EEP, they cannot be expected to achieve clinically reasonable PEEP. On the other hand, geometrical constriction in the connector can potentially result in PEEP as obtained with conventional nasal cannulae.
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Kageyama S, Takeishi N, Harada N, Taniguchi K, Morita K, Wada S. Airway performance in infants with congenital tracheal stenosis associated with unilateral pulmonary agenesis: effect of tracheal shape on energy flux. Med Biol Eng Comput 2022; 60:2335-2348. [DOI: 10.1007/s11517-022-02601-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 06/07/2022] [Indexed: 12/01/2022]
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Ito H, Takeishi N. Editorial for the Special Issue on Advances in Microfluidics for Quantifying Cell Mechanics and Biotransport. Micromachines (Basel) 2022; 13:mi13071127. [PMID: 35888944 PMCID: PMC9319838 DOI: 10.3390/mi13071127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 07/15/2022] [Indexed: 12/07/2022]
Abstract
Microfluidics is a powerful tool to precisely control fluids as well as to manipulate suspended small particles in a micrometer-sized space [...].
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Affiliation(s)
- Hiroaki Ito
- Department of Physics, Graduate School of Science, Chiba University, Yayoi-cho 1-33, Inage-ku, Chiba 263-8522, Japan
- Correspondence: (H.I.); (N.T.)
| | - Naoki Takeishi
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka 560-8531, Japan
- Correspondence: (H.I.); (N.T.)
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Takeishi N, Shigematsu T, Enosaki R, Ishida S, Ii S, Wada S. Development of a mesoscopic framework spanning nanoscale protofibril dynamics to macro-scale fibrin clot formation. J R Soc Interface 2021; 18:20210554. [PMID: 34753310 PMCID: PMC8580471 DOI: 10.1098/rsif.2021.0554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 10/14/2021] [Indexed: 11/23/2022] Open
Abstract
Thrombi form a micro-scale fibrin network consisting of an interlinked structure of nanoscale protofibrils, resulting in haemostasis. It is theorized that the mechanical effect of the fibrin clot is caused by the polymeric protofibrils between crosslinks, or to their dynamics on a nanoscale order. Despite a number of studies, however, it is still unknown, how the nanoscale protofibril dynamics affect the formation of the macro-scale fibrin clot and thus its mechanical properties. A mesoscopic framework would be useful to tackle this multi-scale problem, but it has not yet been established. We thus propose a minimal mesoscopic model for protofibrils based on Brownian dynamics, and performed numerical simulations of protofibril aggregation. We also performed stretch tests of polymeric protofibrils to quantify the elasticity of fibrin clots. Our model results successfully captured the conformational properties of aggregated protofibrils, e.g., strain-hardening response. Furthermore, the results suggest that the bending stiffness of individual protofibrils increases to resist extension.
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Affiliation(s)
- Naoki Takeishi
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama Toyonaka, Osaka 560-8531, Japan
| | - Taiki Shigematsu
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama Toyonaka, Osaka 560-8531, Japan
| | - Ryogo Enosaki
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama Toyonaka, Osaka 560-8531, Japan
| | - Shunichi Ishida
- Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan
| | - Satoshi Ii
- Graduate School of Systems Design, Tokyo Metropolitan University, 1-1 Minami-Osawa Hachioji, Tokyo 192-0397, Japan
| | - Shigeo Wada
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama Toyonaka, Osaka 560-8531, Japan
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Takeishi N, Yamashita H, Omori T, Yokoyama N, Sugihara-Seki M. Axial and Nonaxial Migration of Red Blood Cells in a Microtube. Micromachines (Basel) 2021; 12:mi12101162. [PMID: 34683214 PMCID: PMC8541681 DOI: 10.3390/mi12101162] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 09/22/2021] [Accepted: 09/24/2021] [Indexed: 11/18/2022]
Abstract
Human red blood cells (RBCs) are subjected to high viscous shear stress, especially during microcirculation, resulting in stable deformed shapes such as parachute or slipper shape. Those unique deformed RBC shapes, accompanied with axial or nonaxial migration, cannot be fully described according to traditional knowledge about lateral movement of deformable spherical particles. Although several experimental and numerical studies have investigated RBC behavior in microchannels with similar diameters as RBCs, the detailed mechanical characteristics of RBC lateral movement—in particular, regarding the relationship between stable deformed shapes, equilibrium radial RBC position, and membrane load—has not yet been fully described. Thus, we numerically investigated the behavior of single RBCs with radii of 4 μm in a circular microchannel with diameters of 15 μm. Flow was assumed to be almost inertialess. The problem was characterized by the capillary number, which is the ratio between fluid viscous force and membrane elastic force. The power (or energy dissipation) associated with membrane deformations was introduced to quantify the state of membrane loads. Simulations were performed with different capillary numbers, viscosity ratios of the internal to external fluids of RBCs, and initial RBC centroid positions. Our numerical results demonstrated that axial or nonaxial migration of RBC depended on the stable deformed RBC shapes, and the equilibrium radial position of the RBC centroid correlated well with energy expenditure associated with membrane deformations.
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Affiliation(s)
- Naoki Takeishi
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka 560-8531, Japan; (H.Y.); (M.S.-S.)
- Correspondence: ; Tel./Fax: +81-6-6850-6173
| | - Hiroshi Yamashita
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka 560-8531, Japan; (H.Y.); (M.S.-S.)
- Department of Pure and Applied Physics, Kansai University, 3-3-35 Yamate-cho, Suita 564-8680, Japan
| | - Toshihiro Omori
- Department of Finemechanics, Tohoku University, 6-6-01 Aoba, Sendai 980-8579, Japan;
| | - Naoto Yokoyama
- Department of Mechanical Engineering, Tokyo Denki University, 5 Senju-Asahi, Adachi, Tokyo 120-8551, Japan;
| | - Masako Sugihara-Seki
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka 560-8531, Japan; (H.Y.); (M.S.-S.)
- Department of Pure and Applied Physics, Kansai University, 3-3-35 Yamate-cho, Suita 564-8680, Japan
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Yokoyama N, Takeishi N, Wada S. Cerebrospinal fluid flow driven by arterial pulsations in axisymmetric perivascular spaces: Analogy with Taylor's swimming sheet. J Theor Biol 2021; 523:110709. [PMID: 33862088 DOI: 10.1016/j.jtbi.2021.110709] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 03/19/2021] [Accepted: 03/31/2021] [Indexed: 11/30/2022]
Abstract
Cerebrospinal fluid (CSF) flow in the perivascular space (PVS), which surrounds the arteries in the brain, is of paramount importance in the removal of metabolic waste. Despite a number of experimental and numerical studies regarding CSF flow, the underlying mechanics of CSF flow are still debated, especially regarding whether an arterial pulsation can indeed produce net CSF flow velocity. Furthermore, the relationship between CSF flow and arterial wall pulsation has not been fully defined. To clarify these questions, we numerically investigated the CSF flow in the PVS in an axisymmetric channel with a pulsating boundary, where CSF is modeled as an incompressible, Newtonian viscous fluid in non-porous space. Our numerical results show that the net CSF flow velocity driven by the arterial pulsation is consistent with that of previous animal experiments. However, the peak oscillatory velocity is two orders of magnitude larger than the net velocity. Interestingly, the net CSF flow velocity collapses on the analytical solution derived from the lubrication theory in analogy with Taylor's swimming sheet model.
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Affiliation(s)
- Naoto Yokoyama
- Department of Mechanical Engineering, Tokyo Denki University, 5 Senju-Asahi, Adachi, Tokyo 120-8551, Japan.
| | - Naoki Takeishi
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama Toyonaka, Osaka 560-8531, Japan
| | - Shigeo Wada
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama Toyonaka, Osaka 560-8531, Japan
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Takeishi N, Ito H, Kaneko M, Wada S. Deformation of a Red Blood Cell in a Narrow Rectangular Microchannel. Micromachines (Basel) 2019; 10:E199. [PMID: 30901883 PMCID: PMC6470855 DOI: 10.3390/mi10030199] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 03/15/2019] [Accepted: 03/16/2019] [Indexed: 01/14/2023]
Abstract
The deformability of a red blood cell (RBC) is one of the most important biological parameters affecting blood flow, both in large arteries and in the microcirculation, and hence it can be used to quantify the cell state. Despite numerous studies on the mechanical properties of RBCs, including cell rigidity, much is still unknown about the relationship between deformability and the configuration of flowing cells, especially in a confined rectangular channel. Recent computer simulation techniques have successfully been used to investigate the detailed behavior of RBCs in a channel, but the dynamics of a translating RBC in a narrow rectangular microchannel have not yet been fully understood. In this study, we numerically investigated the behavior of RBCs flowing at different velocities in a narrow rectangular microchannel that mimicked a microfluidic device. The problem is characterized by the capillary number C a , which is the ratio between the fluid viscous force and the membrane elastic force. We found that confined RBCs in a narrow rectangular microchannel maintained a nearly unchanged biconcave shape at low C a , then assumed an asymmetrical slipper shape at moderate C a , and finally attained a symmetrical parachute shape at high C a . Once a RBC deformed into one of these shapes, it was maintained as the final stable configurations. Since the slipper shape was only found at moderate C a , measuring configurations of flowing cells will be helpful to quantify the cell state.
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Affiliation(s)
- Naoki Takeishi
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan.
| | - Hiroaki Ito
- Department of Mechanical Engineering, Osaka University, Suita, Osaka 565-0871, Japan.
- Department of Physics, Graduate School of Science, Chiba University, Chiba 263-8522, Japan.
| | - Makoto Kaneko
- Department of Mechanical Engineering, Osaka University, Suita, Osaka 565-0871, Japan.
| | - Shigeo Wada
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan.
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Abstract
Previous studies have concluded that microparticles (MPs) can more effectively approach the microvessel wall than nanoparticles because of margination. In this study, however, we show that MPs are not marginated in capillaries where the vessel diameter is comparable to that of red blood cells (RBCs). We numerically investigated the behavior of MPs with a diameter of 1 μm in various microvessel sizes, including capillaries. In capillaries, the flow mode of RBCs shifted from multi-file flow to bolus (single-file) flow, and MPs were captured by the bolus flow of the RBCs instead of being marginated. Once MPs were captured, they rarely escaped from the vortex-like flow structures between RBCs. These capture events were enhanced when the hematocrit was decreased, and reduced when the shear rate was increased. Our results suggest that microparticles may be rather inefficient drug carriers when targeting capillaries because of capture events, but nanoparticles, which are more randomly distributed in capillaries, may be more effective carriers.
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Affiliation(s)
- Naoki Takeishi
- Institute for Frontier Life and Medical Sciences, Kyoto University, Department of Biosystems Science, 53 Shogoin-Kawara-cho, Sakyo, Kyoto, 606-8507, Japan
| | - Yohsuke Imai
- School of Engineering, Tohoku University, 6-6-01 Aoba, Aoba, Sendai, 980-8579, Japan.
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Takeishi N, Imai Y, Ishida S, Omori T, Kamm RD, Ishikawa T. Cell adhesion during bullet motion in capillaries. Am J Physiol Heart Circ Physiol 2016; 311:H395-403. [PMID: 27261363 DOI: 10.1152/ajpheart.00241.2016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 05/31/2016] [Indexed: 01/13/2023]
Abstract
A numerical analysis is presented of cell adhesion in capillaries whose diameter is comparable to or smaller than that of the cell. In contrast to a large number of previous efforts on leukocyte and tumor cell rolling, much is still unknown about cell motion in capillaries. The solid and fluid mechanics of a cell in flow was coupled with a slip bond model of ligand-receptor interactions. When the size of a capillary was reduced, the cell always transitioned to "bullet-like" motion, with a consequent decrease in the velocity of the cell. A state diagram was obtained for various values of capillary diameter and receptor density. We found that bullet motion enables firm adhesion of a cell to the capillary wall even for a weak ligand-receptor binding. We also quantified effects of various parameters, including the dissociation rate constant, the spring constant, and the reactive compliance on the characteristics of cell motion. Our results suggest that even under the interaction between P-selectin glycoprotein ligand-1 (PSGL-1) and P-selectin, which is mainly responsible for leukocyte rolling, a cell is able to show firm adhesion in a small capillary. These findings may help in understanding such phenomena as leukocyte plugging and cancer metastasis.
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Affiliation(s)
- Naoki Takeishi
- Graduate School of Biomedical Engineering, Tohoku University, Aoba, Sendai, Japan
| | - Yohsuke Imai
- School of Engineering, Tohoku University, Aoba, Sendai, Japan;
| | - Shunichi Ishida
- Graduate School of Biomedical Engineering, Tohoku University, Aoba, Sendai, Japan
| | - Toshihiro Omori
- School of Engineering, Tohoku University, Aoba, Sendai, Japan
| | - Roger D Kamm
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts; and Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Takuji Ishikawa
- Graduate School of Biomedical Engineering, Tohoku University, Aoba, Sendai, Japan; School of Engineering, Tohoku University, Aoba, Sendai, Japan
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Takeishi N, Imai Y, Yamaguchi T, Ishikawa T. Flow of a circulating tumor cell and red blood cells in microvessels. Phys Rev E Stat Nonlin Soft Matter Phys 2015; 92:063011. [PMID: 26764808 DOI: 10.1103/physreve.92.063011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Indexed: 06/05/2023]
Abstract
Quantifying the behavior of circulating tumor cells (CTCs) in the blood stream is of fundamental importance for understanding metastasis. Here, we investigate the flow mode and velocity of CTCs interacting with red blood cells (RBCs) in various sized microvessels. The flow of leukocytes in microvessels has been described previously; a leukocyte forms a train with RBCs in small microvessels and exhibits margination in large microvessels. Important differences in the physical properties of leukocytes and CTCs result from size. The dimensions of leukocytes are similar to those of RBCs, but CTCs are significantly larger. We investigate numerically the size effects on the flow mode and the cell velocity, and we identify similarities and differences between leukocytes and CTCs. We find that a transition from train formation to margination occurs when (R-a)/t(R)≈1, where R is the vessel radius, a is the cell radius, and t(R) is the thickness of RBCs, but that the motion of RBCs differs from the case of leukocytes. Our results also show that the velocities of CTCs and leukocytes are larger than the average blood velocity, but only CTCs move faster than RBCs for microvessels of R/a≈1.5-2.0. These findings are expected to be useful not only for understanding metastasis, but also for developing microfluidic devices.
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Affiliation(s)
- Naoki Takeishi
- Graduate School of Biomedical Engineering, Tohoku University, 6-6-01 Aoba, Aoba, Sendai 980-8579, Japan
| | - Yohsuke Imai
- School of Engineering, Tohoku University, 6-6-01 Aoba, Aoba, Sendai 980-8579, Japan
| | - Takami Yamaguchi
- Graduate School of Biomedical Engineering, Tohoku University, 6-6-01 Aoba, Aoba, Sendai 980-8579, Japan
| | - Takuji Ishikawa
- School of Engineering, Tohoku University, 6-6-01 Aoba, Aoba, Sendai 980-8579, Japan
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Abstract
We numerically investigated margination of leukocytes at arteriole shear rate in straight circular channels with diameters ranging from 10 to 22 μm. Our results demonstrated that passing motion of RBCs effectively induces leukocyte margination not only in small channels but also in large channels. A longer time is needed for margination to occur in a larger channel, but once a leukocyte has marginated, passing motion of RBCs occurs continuously independent of the channel diameter, and leukocyte margination is sustained for a long duration. We also show that leukocytes rarely approach the wall surface to within a microvillus length at arteriole shear rate. We numerically investigated margination of leukocytes at arteriole shear rate in straight circular channels with diameters ranging from 10 to 22 µm. Our results demonstrated that passing motion of RBCs effectively induces leukocyte margination not only in small channels but also in large channels. We also show that leukocytes rarely approach the wall surface to within a microvillus length at arteriole shear rate.
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Affiliation(s)
- Naoki Takeishi
- Department of Biomedical Engineering, Tohoku University, AobaSendai, Japan
| | - Yohsuke Imai
- Department of Bioengineering and Robotics, Tohoku University, AobaSendai, Japan
| | - Keita Nakaaki
- Department of Bioengineering and Robotics, Tohoku University, AobaSendai, Japan
| | - Takami Yamaguchi
- Department of Biomedical Engineering, Tohoku University, AobaSendai, Japan
| | - Takuji Ishikawa
- Department of Bioengineering and Robotics, Tohoku University, AobaSendai, Japan
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Mori M, Kawaguchi M, Takeishi N, Nagano Y, Yue M. [Survey on sexual activities during pregnancy--responses from husbands]. Josanpu Zasshi 1981; 35:526-31. [PMID: 6911195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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