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Schäfer F, Sturdy J, Hellevik LR. Age and sex-dependent sensitivity analysis of a common carotid artery model. Biomech Model Mechanobiol 2024; 23:825-843. [PMID: 38369558 PMCID: PMC11101589 DOI: 10.1007/s10237-023-01808-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 12/22/2023] [Indexed: 02/20/2024]
Abstract
The common carotid artery (CCA) is an accessible and informative site for assessing cardiovascular function which makes it a prime candidate for clinically relevant computational modelling. The interpretation of supplemental information possible through modelling is encumbered by measurement uncertainty and population variability in model parameters. The distribution of model parameters likely depends on the specific sub-population of interest and delineation based on sex, age or health status may correspond to distinct ranges of typical parameter values. To assess this impact in a 1D-CCA-model, we delineated specific sub-populations based on age, sex and health status and carried out uncertainty quantification and sensitivity analysis for each sub-population. We performed a structured literature review to characterize sub-population-specific variabilities for eight model parameters without consideration of health status; variations for a healthy sub-populations were based on previously established references values. The variabilities of diameter and distensibility found in the literature review differed from those previously established in a healthy population. Model diameter change and pulse pressure were most sensitive to variations in distensibility, while pressure was most sensitive to resistance in the Windkessel model for all groups. Uncertainties were lower when variabilities were based on a healthy sub-population; however, the qualitative distribution of sensitivity indices was largely similar between the healthy and general population. Average sensitivity of the pressure waveform showed a moderate dependence on age with decreasing sensitivity to distal resistance and increasing sensitivity to distensibility and diameter. The female population was less sensitive to variations in diameter but more sensitive to distensibility coefficient than the male population. Overall, as hypothesized input variabilities differed between sub-populations and resulted in distinct uncertainties and sensitivities of the 1D-CCA-model outputs, particularly over age for the pressure waveform and between males and females for pulse pressure.
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Affiliation(s)
- Friederike Schäfer
- Division of Biomechanics, Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Richard Birkelands vei 1A, 7034, Trondheim, Norway.
| | - Jacob Sturdy
- Division of Biomechanics, Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Richard Birkelands vei 1A, 7034, Trondheim, Norway
| | - Leif Rune Hellevik
- Division of Biomechanics, Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Richard Birkelands vei 1A, 7034, Trondheim, Norway
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2
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Michel ME, Wen CC, Yee SW, Giacomini KM, Hamdoun A, Nicklisch SCT. TICBase: Integrated Resource for Data on Drug and Environmental Chemical Interactions with Mammalian Drug Transporters. Clin Pharmacol Ther 2023; 114:1293-1303. [PMID: 37657924 DOI: 10.1002/cpt.3036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Accepted: 07/28/2023] [Indexed: 09/03/2023]
Abstract
Environmental health science seeks to predict how environmental toxins, chemical toxicants, and prescription drugs accumulate and interact within the body. Xenobiotic transporters of the ATP-binding cassette (ABC) and solute carrier (SLC) superfamilies are major determinants of the uptake and disposition of xenobiotics across the kingdoms of life. The goal of this study was to integrate drug and environmental chemical interactions of mammalian ABC and SLC proteins in a centralized, integrative database. We built upon an existing publicly accessible platform-the "TransPortal"-which was updated with novel data and searchable features on transporter-interfering chemicals from manually curated literature data. The integrated resource TransPortal-TICBase (https://transportal.compbio.ucsf.edu) now contains information on 46 different mammalian xenobiotic transporters of the ABC- and SLC-type superfamilies, including 13 newly added rodent and 2 additional human drug transporters, 126 clinical drug-drug interactions, and a more than quadrupled expansion of the initial in vitro chemical interaction data from 1,402 to 6,296 total interactions. Based on our updated database, environmental interference with major human and rodent drug transporters occurs across the ABC- and SLC-type superfamilies, with kinetics indicating that some chemicals, such as the ionic liquid 1-hexylpyridinium chloride and the antiseptic chlorhexidine, can act as strong inhibitors with potencies similar or even higher than pharmacological model inhibitors. The new integrated web portal serves as a central repository of current and emerging data for interactions of prescription drugs and environmental chemicals with human drug transporters. This archive has important implications for predicting adverse drug-drug and drug-environmental chemical interactions and can serve as a reference website for the broader scientific community of clinicians and researchers.
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Affiliation(s)
- Matthew E Michel
- Department of Environmental Toxicology, University of California, Davis, Davis, California, USA
| | | | - Sook Wah Yee
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, USA
| | - Kathleen M Giacomini
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, USA
| | - Amro Hamdoun
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, USA
| | - Sascha C T Nicklisch
- Department of Environmental Toxicology, University of California, Davis, Davis, California, USA
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3
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Knüppel F, Sun A, Wurm FH, Hussong J, Torner B. Effect of Particle Migration on the Stress Field in Microfluidic Flows of Blood Analog Fluids at High Reynolds Numbers. MICROMACHINES 2023; 14:1494. [PMID: 37630030 PMCID: PMC10456677 DOI: 10.3390/mi14081494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 07/19/2023] [Accepted: 07/21/2023] [Indexed: 08/27/2023]
Abstract
In the present paper, we investigate how the reductions in shear stresses and pressure losses in microfluidic gaps are directly linked to the local characteristics of cell-free layers (CFLs) at channel Reynolds numbers relevant to ventricular assist device (VAD) applications. For this, detailed studies of local particle distributions of a particulate blood analog fluid are combined with wall shear stress and pressure loss measurements in two complementary set-ups with identical flow geometry, bulk Reynolds numbers and particle Reynolds numbers. For all investigated particle volume fractions of up to 5%, reductions in the stress and pressure loss were measured in comparison to a flow of an equivalent homogeneous fluid (without particles). We could explain this due to the formation of a CFL ranging from 10 to 20 μm. Variations in the channel Reynolds number between Re = 50 and 150 did not lead to measurable changes in CFL heights or stress reductions for all investigated particle volume fractions. These measurements were used to describe the complete chain of how CFL formation leads to a stress reduction, which reduces the apparent viscosity of the suspension and results in the Fåhræus-Lindqvist effect. This chain of causes was investigated for the first time for flows with high Reynolds numbers (Re∼100), representing a flow regime which can be found in the narrow gaps of a VAD.
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Affiliation(s)
- Finn Knüppel
- Institute of Turbomachinery, Faculty for Mechanical Engineering and Ship Design, University of Rostock, 18055 Rostock, Germany; (F.K.); (F.-H.W.)
| | - Ang Sun
- Institute for Fluid Mechanics and Aerodynamics, Technical University of Darmstadt, 64287 Darmstadt, Germany; (A.S.); (J.H.)
| | - Frank-Hendrik Wurm
- Institute of Turbomachinery, Faculty for Mechanical Engineering and Ship Design, University of Rostock, 18055 Rostock, Germany; (F.K.); (F.-H.W.)
| | - Jeanette Hussong
- Institute for Fluid Mechanics and Aerodynamics, Technical University of Darmstadt, 64287 Darmstadt, Germany; (A.S.); (J.H.)
| | - Benjamin Torner
- Institute of Turbomachinery, Faculty for Mechanical Engineering and Ship Design, University of Rostock, 18055 Rostock, Germany; (F.K.); (F.-H.W.)
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Romańska J, Wawrzoniak T, Hołowaty D, Mazanowska N, Krajewski P. Point-of-Care Verification of Blood Culture Volume in Neonates: A Feasibility Trial. JOURNAL OF MOTHER AND CHILD 2023; 27:83-92. [PMID: 37561917 PMCID: PMC10414768 DOI: 10.34763/jmotherandchild.20232701.d-22-00063] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 02/01/2023] [Indexed: 08/12/2023]
Abstract
BACKGROUND Blood cultures remain the gold standard for the diagnosis of sepsis. However, volumes of blood submitted for cultures often do not match the recommended values. We propose a simple intervention aimed to verify the volume of blood sampled using a scale. This study was undertaken in preparation for a future, multicenter, pre- and post-intervention trial. Our primary objective was to test the feasibility (uptake and retention) of this future intervention. MATERIALS AND METHODS This study was conducted at a neonatal department in Warsaw, Poland, over a period of eight months (May to December 2020). Before starting the study, we undertook an educational intervention focused on obtaining adequate blood volumes for culture. The culture bottles that were weighed in advance were distributed in all blood collection areas. Blood volume was verified by weighing the bottle immediately after blood inoculation. The calculated value was communicated to the collecting clinician and recorded. The primary outcome measure was the percentage of blood culture submissions for which the blood volume inoculated into the bottles was determined by weighing. RESULTS During the study period, 244 blood samples were collected for culture, out of which 205 samples were weighed (84.0%, CI95 [78.8% to 88.4%]). This high proportion remained stable throughout the study period. We have not observed any adverse events related to the study. CONCLUSIONS The point-of-care verification of blood culture volume using a scale was feasible to implement. Since we have met our pre-established criterion for success, a future, definitive trial is likely to proceed.
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Affiliation(s)
- Justyna Romańska
- Department of Obstetrics and Gynaecology, Division of Neonatology and Neonatal Intensive Care, Medical University of Warsaw, Warsaw, Poland
| | - Tomasz Wawrzoniak
- Department of Obstetrics and Gynaecology, Division of Neonatology and Neonatal Intensive Care, Medical University of Warsaw, Warsaw, Poland
| | - Dominika Hołowaty
- Department of Obstetrics and Gynaecology, Division of Neonatology and Neonatal Intensive Care, Medical University of Warsaw, Warsaw, Poland
| | - Natalia Mazanowska
- Department of Obstetrics and Gynaecology, Division of Neonatology and Neonatal Intensive Care, Medical University of Warsaw, Warsaw, Poland
| | - Paweł Krajewski
- Department of Obstetrics and Gynaecology, Division of Neonatology and Neonatal Intensive Care, Medical University of Warsaw, Warsaw, Poland
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Nowak M, Divo E, Adamczyk WP. Multiscale model for blood flow after a bileaflet artificial aortic valve implantation. Comput Biol Med 2023; 158:106805. [PMID: 37019010 DOI: 10.1016/j.compbiomed.2023.106805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 02/15/2023] [Accepted: 03/20/2023] [Indexed: 04/05/2023]
Abstract
Cardiovascular diseases are the leading cause of mortality in the world, mainly due to atherosclerosis and its consequences. The article presents the numerical model of the blood flow through artificial aortic valve. The overset mesh approach was applied to simulate the valve leaflets motion and to realize the moving mesh, in the aortic arch and the main branches of cardiovascular system. To capture the cardiac system's response and the effect of vessel compliance on the outlet pressure, the lumped parameter model has been also included within the solution procedure. Three different turbulence modeling approaches were used and compared - the laminar, k-ϵ and k-ω model. The simulation results were also compared with the model excluding the moving valve geometry and the importance of the lumped parameter model for the outlet boundary condition was analyzed. Proposed numerical model and protocol was found as suitable for performing the virtual operations on the real patient vasculature geometry. The time-efficient turbulence model and overall solving procedure allows to support the clinicians in making decisions about the patient treatment and to predict the results of the future surgery.
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Robert Bateman A, Alexander Bateman G, Barber T. Investigating the hemodynamic implications of triangular cross-sectioned superior sagittal sinus vessels and the errors associated with idealised modelling. J Biomech 2023; 149:111507. [PMID: 36868042 DOI: 10.1016/j.jbiomech.2023.111507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 01/31/2023] [Accepted: 02/13/2023] [Indexed: 02/17/2023]
Abstract
The superior sagittal sinus (SSS) is a blood vessel that is often observed to be approximately triangular in cross-section, due to how the venous wall attaches to the surrounding tissue. Despite this, the vessel has been assumed to be circular, when models are generated without patient-specific data. In this study, the differences between the cerebral hemodynamics of one circular, three triangular and five patient-specific cross-sectional models of a SSS were conducted. The errors associated with using circular cross-sectioned flow extensions were also determined. Computational fluid dynamics (CFD) models were generated from these geometries, with a population mean transient blood flow profile incorporated. The maximal helicity of the fluid flow was found to be elevated in the triangular cross-section, compared to the circular, with a higher wall shear stress (WSS) observed over a smaller, more concentrated region on the posterior sinus wall. The errors associated with using a circular cross-section were detailed, with the cross-sectional area appearing to have a greater influence on the hemodynamic parameters than the triangularity or circularity of the cross-section. This highlighted the importance of exhibiting caution when incorporating idealised modelling, especially when commenting on the true hemodynamics of these models. Errors were also found to be induced when using a circular cross-sectioned flow extension, for a geometry which was non-circular. This study highlights the importance of understanding the human anatomy when modelling blood vessels.
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Affiliation(s)
| | - Grant Alexander Bateman
- Department of Medical Imaging, John Hunter Hospital, Newcastle, NSW, Australia; Newcastle University Faculty of Health, Callaghan Campus, Newcastle, NSW, Australia
| | - Tracie Barber
- School of Mechanical Engineering, University of New South Wales, Sydney, NSW, Australia
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7
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Cashin JL, Wirtz AJ, Genin GM, Zayed M. A Fenestrated Balloon Expandable Stent System for the Treatment of Aortoiliac Occlusive Disease. JOURNAL OF ENGINEERING AND SCIENCE IN MEDICAL DIAGNOSTICS AND THERAPY 2023; 6:011004. [PMID: 36353246 PMCID: PMC9635567 DOI: 10.1115/1.4055877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 09/24/2022] [Indexed: 06/16/2023]
Abstract
In aortoiliac occlusive disease, atherosclerotic plaques can occlude the distal aortic bifurcation and proximal bilateral iliac artery and thus cause ischemia in the lower extremity. This is typically treated by restoring patency with balloon expandable stents. Stents are typically deployed in a "kissing stent" configuration into the bilateral iliac arteries and into the distal aortic bifurcation lumen to restore antegrade arterial flow. However, these stents typically become re-occluded by plaques. To understand the reasons for this and look for solutions, we simulated flow dynamics in the aortic bifurcation in the presence and absence of stents using computational fluid dynamics. Results demonstrated that the kissing stent configuration was associated with high levels of vorticity and flow constriction. These prothrombotic variables were alleviated in an alternative, aortoiliac fenestrated (AIFEN), tapered, and balloon-expandable stent design. Our findings suggest that stent design can be tailored to improve flow fields for aortoiliac stenting.
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Affiliation(s)
- John L Cashin
- Department of Surgery, Section of Vascular Surgery, Washington University School of Medicine, St. Louis, MO 63110
| | - Alex J Wirtz
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO 63130
| | - Guy M Genin
- NSF Science and Technology Center for Engineering Mechanobiology, Washington University in St. Louis, St. Louis, MO 63130; Departments of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO 63130; Department of Neurological Surgery, Washington University in St. Louis, St. Louis, MO 63130
| | - Mohamed Zayed
- Cardiovascular Research Innovation in Surgery & Engineering Center, and the Section of Vascular Surgery, Washington University School of Medicine, St. Louis, MO 63110
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8
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Jones AW, Tilson C. Distribution ratios of ethanol and water between whole blood, plasma, serum, and erythrocytes: Recommendations for interpreting clinical laboratory results in a legal context. J Forensic Sci 2023; 68:9-21. [PMID: 36317846 DOI: 10.1111/1556-4029.15164] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 10/15/2022] [Accepted: 10/17/2022] [Indexed: 12/30/2022]
Abstract
This article reviews the scientific literature dealing with the distribution of ethanol and water between whole blood (WB), plasma, serum, and erythrocytes (red-blood cells). Knowledge of the ethanol distribution ratio is important when analytical results derived from hospital clinical laboratories are interpreted in a forensic context, such as during the prosecution of traffic offenders. Statutory blood-alcohol concentration (BAC) limits for driving are defined as the concentration of ethanol in WB and not in plasma, serum or red-blood cells. These bio-fluids differ in their water content and thereby the concentrations of ethanol. Plasma and serum contain ~90%-92% w/w water, WB ~78%-80% w/w and erythrocytes ~64%-66% w/w. The mean plasma/WB and serum/WB distribution ratios of ethanol are therefore expected to be ~1.15:1 (91/79 = 1.15), which is in good agreement with values determined empirically. However, in individual cases, the actual distribution ratio will depend on the person's age, gender, and biochemical and hematological properties of the blood specimen, such as its hematocrit. For legal purposes, we recommend that the concentration of ethanol in plasma or serum determined at hospital laboratories is divided by a factor of 1.2, which would provide a conservative estimate of the co-existing BAC and the chance of overestimating the true value is only 1 in 2000 (0.05%).
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Affiliation(s)
- Alan Wayne Jones
- Department of Biomedical and Clinical Sciences, Division of Clinical Chemistry and Pharmacology, University of Linköping, Linköping, Sweden
| | - Christopher Tilson
- Georgia Bureau of Investigation, Division of Forensic Sciences, Decatur, Georgia, USA
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Tripathy HP, Pattanaik P, Mishra DK, Kamilla SK, Holderbaum W. Experimental and probabilistic model validation of ultrasonic MEMS transceiver for blood glucose sensing. Sci Rep 2022; 12:21259. [PMID: 36481774 PMCID: PMC9732296 DOI: 10.1038/s41598-022-25717-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022] Open
Abstract
In contrast to traditional laboratory glucose monitoring, recent developments have focused on blood glucose self-monitoring and providing patients with a self-monitoring device. This paper proposes a system based on ultrasound principles for quantifying glucose levels in blood by conducting an in-vitro experiment with goat blood before human blood. The ultrasonic transceiver is powered by a frequency generator that operates at 40 kHz and 1.6 V, and variations in glucose level affect the ultrasonic transceiver readings. The RVM probabilistic model is used to determine the variation in glucose levels in a blood sample. Blood glucose levels are measured simultaneously using a commercial glucose metre for confirmation. The experimental data values proposed are highly correlated with commercial glucose metre readings. The proposed ultrasonic MEMS-based blood glucometer measures a glucose level of [Formula: see text] mg/dl. In the near future, the miniature version of the experimental model may be useful to human society.
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Affiliation(s)
- Hara Prasada Tripathy
- grid.412612.20000 0004 1760 9349Semiconductor Research Laboratory, Faculty of Engineering and Technology (ITER), Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar, 751030 India
| | - Priyabrata Pattanaik
- grid.412612.20000 0004 1760 9349Semiconductor Research Laboratory, Faculty of Engineering and Technology (ITER), Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar, 751030 India
| | - Dilip Kumar Mishra
- grid.412612.20000 0004 1760 9349Semiconductor Research Laboratory, Faculty of Engineering and Technology (ITER), Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar, 751030 India
| | - Sushanta Kumar Kamilla
- grid.412612.20000 0004 1760 9349Semiconductor Research Laboratory, Faculty of Engineering and Technology (ITER), Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar, 751030 India
| | - William Holderbaum
- grid.9435.b0000 0004 0457 9566School of Biological Science, Biomedical Engineering, University of Reading, Whiteknights, RG6 6AY UK
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Effect of hemoglobin hydration on the physical properties of erythrocyte cytoplasm and whole blood. Electrochim Acta 2022. [DOI: 10.1016/j.electacta.2022.141560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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11
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Rubio A, López M, Rodrigues T, Campo-Deaño L, Vega EJ. A particulate blood analogue based on artificial viscoelastic blood plasma and RBC-like microparticles at a concentration matching the human haematocrit. SOFT MATTER 2022; 18:7510-7523. [PMID: 36148801 DOI: 10.1039/d2sm00947a] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
There has been enormous interest in the production of fluids with rheological properties similar to those of real blood over the last few years. Application fields range from biomicrofluidics (microscale) to forensic science (macroscale). The inclusion of flexible microparticles in blood analogue fluids has been demonstrated to be essential in order to reproduce the behaviour of blood flow in these fields. Here, we describe a protocol to produce a whole human blood analogue composed of a proposed plasma analogue and flexible spherical microparticles that mimic the key structural attributes of RBCs (size and mechanical properties), at a concentration matching the human haematocrit (∼42% by volume). Polydimethylsiloxane (PDMS) flexible microparticles were used to mimic RBCs, whose capability to deform is tunable by means of the mixing ratio of the PDMS precursor. Their flow through glass micronozzles allowed us to find the appropriate mixing ratio of PDMS to have approximately the same Young's modulus (E) as that exhibited by real RBCs. Shear and extensional rheology and microrheology techniques were used to match the properties exhibited by human plasma and whole blood at body temperature (37 °C). Finally, we study the flow of our proposed fluid through a microfluidic channel, showing the in vitro reproduction of the multiphase flow effects taking place in the human microcirculatory system, such as the cell-free layer (CFL) and the Fåhræus-Lindqvist effect. A macroscale application in the field of forensic science is also presented, concerning the impact of our blood analogue droplets on a solid surface for bloodstain pattern analysis.
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Affiliation(s)
- A Rubio
- Depto. de Ingeniería Mecánica, Energética y de los Materiales and Instituto de Computación Científica Avanzada (ICCAEx), Universidad de Extremadura, E-06006, Badajoz, Spain. ejvega@unex
| | - M López
- Depto. de Ingeniería Mecánica, Energética y de los Materiales and Instituto de Computación Científica Avanzada (ICCAEx), Universidad de Extremadura, E-06006, Badajoz, Spain. ejvega@unex
| | - T Rodrigues
- CEFT, Depto. de Engenharia Mecânica, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
- ALiCE, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
| | - L Campo-Deaño
- CEFT, Depto. de Engenharia Mecânica, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
- ALiCE, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
| | - E J Vega
- Depto. de Ingeniería Mecánica, Energética y de los Materiales and Instituto de Computación Científica Avanzada (ICCAEx), Universidad de Extremadura, E-06006, Badajoz, Spain. ejvega@unex
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Jubelin C, Muñoz-Garcia J, Griscom L, Cochonneau D, Ollivier E, Heymann MF, Vallette FM, Oliver L, Heymann D. Three-dimensional in vitro culture models in oncology research. Cell Biosci 2022; 12:155. [PMID: 36089610 PMCID: PMC9465969 DOI: 10.1186/s13578-022-00887-3] [Citation(s) in RCA: 70] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 08/18/2022] [Indexed: 11/10/2022] Open
Abstract
AbstractCancer is a multifactorial disease that is responsible for 10 million deaths per year. The intra- and inter-heterogeneity of malignant tumors make it difficult to develop single targeted approaches. Similarly, their diversity requires various models to investigate the mechanisms involved in cancer initiation, progression, drug resistance and recurrence. Of the in vitro cell-based models, monolayer adherent (also known as 2D culture) cell cultures have been used for the longest time. However, it appears that they are often less appropriate than the three-dimensional (3D) cell culture approach for mimicking the biological behavior of tumor cells, in particular the mechanisms leading to therapeutic escape and drug resistance. Multicellular tumor spheroids are widely used to study cancers in 3D, and can be generated by a multiplicity of techniques, such as liquid-based and scaffold-based 3D cultures, microfluidics and bioprinting. Organoids are more complex 3D models than multicellular tumor spheroids because they are generated from stem cells isolated from patients and are considered as powerful tools to reproduce the disease development in vitro. The present review provides an overview of the various 3D culture models that have been set up to study cancer development and drug response. The advantages of 3D models compared to 2D cell cultures, the limitations, and the fields of application of these models and their techniques of production are also discussed.
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A realistic arteriovenous dialysis graft model for hemodynamic simulations. PLoS One 2022; 17:e0269825. [PMID: 35862379 PMCID: PMC9302782 DOI: 10.1371/journal.pone.0269825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 05/30/2022] [Indexed: 11/19/2022] Open
Abstract
Objective The hemodynamic benefit of novel arteriovenous graft (AVG) designs is typically assessed using computational models that assume highly idealized graft configurations and/or simplified boundary conditions representing the peripheral vasculature. The objective of this study is to evaluate whether idealized AVG models are suitable for hemodynamic evaluation of new graft designs, or whether more realistic models are required. Methods An idealized and a realistic, clinical imaging based, parametrized AVG geometry were created. Furthermore, two physiological boundary condition models were developed to represent the peripheral vasculature. We assessed how graft geometry (idealized or realistic) and applied boundary condition models of the peripheral vasculature (physiological or distal zero-flow) impacted hemodynamic metrics related to AVG dysfunction. Results Anastomotic regions exposed to high WSS (>7, ≤40 Pa), very high WSS (>40 Pa) and highly oscillatory WSS were larger in the simulations using the realistic AVG geometry. The magnitude of velocity perturbations in the venous segment was up to 1.7 times larger in the realistic AVG geometry compared to the idealized one. When applying a (non-physiological zero-flow) boundary condition that neglected blood flow to and from the peripheral vasculature, we observed large regions exposed to highly oscillatory WSS. These regions could not be observed when using either of the newly developed distal boundary condition models. Conclusion Hemodynamic metrics related to AVG dysfunction are highly dependent on the geometry and the distal boundary condition model used. Consequently, the hemodynamic benefit of a novel graft design can be misrepresented when using idealized AVG modelling setups.
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Abstract
Arterial stenosis is a problem of immediate significance, as cardiovascular disease is the number one leading cause of death worldwide. Generally, the study of stenotic flow assumes a smooth, curved stenosis and artery. However, the real situation is unlikely to present an infinitely smooth-surfaced arterial stenosis. Here, the impact of surface roughness on the flow in an arterial stenosis was studied via a computational fluid dynamics analysis. A patient-specific geometry with a smooth surface was reconstructed, and a partially rough model was built by artificially adding random roughness only on the stenotic region of the smooth model. It was found that the flow was oscillatory downstream of the stenosis in the models. A slightly lower velocity near the wall and more oscillatory flows were observed due to the presence of the roughness in the stenotic region. However, the pressure distributions did not vary significantly between the smooth and rough models. The differences in the wall shear metrics were slight in the stenotic region and became larger in the downstream region of the models.
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15
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Liu X, Aslan S, Kim B, Warburton L, Jackson D, Muhuri A, Subramanian A, Mass P, Cleveland V, Loke YH, Hibino N, Olivieri L, Krieger A. Computational Fontan Analysis: Preserving Accuracy While Expediting Workflow. World J Pediatr Congenit Heart Surg 2022; 13:293-301. [PMID: 35446218 DOI: 10.1177/21501351211073619] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Background: Postoperative outcomes of the Fontan operation have been linked to geometry of the cavopulmonary pathway, including graft shape after implantation. Computational fluid dynamics (CFD) simulations are used to explore different surgical options. The objective of this study is to perform a systematic in vitro validation for investigating the accuracy and efficiency of CFD simulation to predict Fontan hemodynamics. Methods: CFD simulations were performed to measure indexed power loss (iPL) and hepatic flow distribution (HFD) in 10 patient-specific Fontan models, with varying mesh and numerical solvers. The results were compared with a novel in vitro flow loop setup with 3D printed Fontan models. A high-resolution differential pressure sensor was used to measure the pressure drop for validating iPL predictions. Microparticles with particle filtering system were used to measure HFD. The computational time was measured for a representative Fontan model with different mesh sizes and numerical solvers. Results: When compared to in vitro setup, variations in CFD mesh sizes had significant effect on HFD (P = .0002) but no significant impact on iPL (P = .069). Numerical solvers had no significant impact in both iPL (P = .50) and HFD (P = .55). A transient solver with 0.5 mm mesh size requires computational time 100 times more than a steady solver with 2.5 mm mesh size to generate similar results. Conclusions: The predictive value of CFD for Fontan planning can be validated against an in vitro flow loop. The prediction accuracy can be affected by the mesh size, model shape complexity, and flow competition.
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Affiliation(s)
- Xiaolong Liu
- Department of Mechanical Engineering, 1466Johns Hopkins University, Baltimore, MD, USA.,Department of Mechanical Engineering, 1068University of Maryland, College Park, MD, USA
| | - Seda Aslan
- Department of Mechanical Engineering, 1466Johns Hopkins University, Baltimore, MD, USA.,Department of Mechanical Engineering, 1068University of Maryland, College Park, MD, USA
| | - Byeol Kim
- Department of Mechanical Engineering, 1466Johns Hopkins University, Baltimore, MD, USA.,Department of Mechanical Engineering, 1068University of Maryland, College Park, MD, USA
| | - Linnea Warburton
- Department of Mechanical Engineering, 1068University of Maryland, College Park, MD, USA
| | - Derrick Jackson
- Department of Mechanical Engineering, 1068University of Maryland, College Park, MD, USA
| | - Abir Muhuri
- Department of Mechanical Engineering, 1068University of Maryland, College Park, MD, USA
| | - Akshay Subramanian
- Department of Mechanical Engineering, 1068University of Maryland, College Park, MD, USA
| | - Paige Mass
- Sheikh Zayed Institute for Pediatric Surgical Innovation, 8404Children's National Medical Center, Washington, DC, USA
| | - Vincent Cleveland
- Sheikh Zayed Institute for Pediatric Surgical Innovation, 8404Children's National Medical Center, Washington, DC, USA
| | - Yue-Hin Loke
- 8404Division of Cardiology, Children's National Medical Center, Washington, DC, USA
| | - Narutoshi Hibino
- 2462Department of Cardiac Surgery, University of Chicago/21880Advocate Children's Hospital, Chicago, IL, USA
| | - Laura Olivieri
- Sheikh Zayed Institute for Pediatric Surgical Innovation, 8404Children's National Medical Center, Washington, DC, USA.,8404Division of Cardiology, Children's National Medical Center, Washington, DC, USA
| | - Axel Krieger
- Department of Mechanical Engineering, 1466Johns Hopkins University, Baltimore, MD, USA.,Department of Mechanical Engineering, 1068University of Maryland, College Park, MD, USA
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16
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Blood Flow Simulation to Determine the Risk of Thrombosis in the Fontan Circulation: Comparison between Atriopulmonary and Total Cavopulmonary Connections. FLUIDS 2022. [DOI: 10.3390/fluids7040138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Three-dimensional computational fluid dynamics (CFD) simulations were performed in the anastomotic region of the Fontan route between the venae cava and pulmonary arteries to investigate the risk of thrombosis due to blood stasis in the Fontan circulation. The finite volume method based on the time-averaged continuity and Navier–Stokes equations combined with the k-ω SST turbulent model was used in the CFD simulations. Low shear rate (SR) and SR on the wall (WSR) of <10 s−1 were used as markers to assess blood stasis as a cause of blood coagulation. Simulated blood flow velocity and both SR and WSR were reduced in the right atrium (RA) as the cavity of a flow channel in the atriopulmonary connection (APC) Fontan model, whereas the values increased in the total cavopulmonary connection (TCPC) Fontan model, which has no cavity. The volume of SR <10 s−1 and wall surface area of WSR <10 s−1 were, respectively, 4.6–261.8 cm3 and 1.2–38.3 cm2 in the APC Fontan model, and 0.1–0.3 cm3 and 0.1–0.6 cm2 in the TCPC Fontan model. The SR and WSR increased in the APC model with a normal-sized RA and the TCPC model as the flow rate of blood from the inferior vena cava increased with exercise; however, the SR and WSR in the RA decreased in the APC model with a dilated RA owing to the development of a recirculating flow. These findings suggest that the APC Fontan has a higher risk of thrombosis due to blood stasis than the TCPC Fontan and a higher RA dilation is associated with a higher risk of thrombosis from a fluid mechanics perspective.
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17
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Bappoo N, Syed MBJ, Khinsoe G, Kelsey LJ, Forsythe RO, Powell JT, Hoskins PR, McBride OMB, Norman PE, Jansen S, Newby DE, Doyle BJ. Low Shear Stress at Baseline Predicts Expansion and Aneurysm-Related Events in Patients With Abdominal Aortic Aneurysm. Circ Cardiovasc Imaging 2021; 14:1112-1121. [PMID: 34875845 DOI: 10.1161/circimaging.121.013160] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Low shear stress has been implicated in abdominal aortic aneurysm (AAA) expansion and clinical events. We tested the hypothesis that low shear stress in AAA at baseline is a marker of expansion rate and future aneurysm-related events. METHODS Patients were imaged with computed tomography angiography at baseline and followed up every 6 months >24 months with ultrasound measurements of maximum diameter. From baseline computed tomography angiography, we reconstructed 3-dimensional models for automated computational fluid dynamics simulations and computed luminal shear stress. The primary composite end point was aneurysm repair and/or rupture, and the secondary end point was aneurysm expansion rate. RESULTS We included 295 patients with median AAA diameter of 49 mm (interquartile range, 43-54 mm) and median follow-up of 914 (interquartile range, 670-1112) days. There were 114 (39%) aneurysm-related events, with 13 AAA ruptures and 98 repairs (one rupture was repaired). Patients with low shear stress (<0.4 Pa) experienced a higher number of aneurysm-related events (44%) compared with medium (0.4-0.6 Pa; 27%) and high (>0.6 Pa; 29%) shear stress groups (P=0.010). This association was independent of known risk factors (adjusted hazard ratio, 1.72 [95% CI, 1.08-2.73]; P=0.023). Low shear stress was also independently associated with AAA expansion rate (β=+0.28 mm/y [95% CI, 0.02-0.53]; P=0.037). CONCLUSIONS We show for the first time that low shear stress (<0.4 Pa) at baseline is associated with both AAA expansion and future aneurysm-related events. Aneurysms within the lowest tertile of shear stress, versus those with higher shear stress, were more likely to rupture or reach thresholds for elective repair. Larger prospective validation trials are needed to confirm these findings and translate them into clinical management.
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Affiliation(s)
- Nikhilesh Bappoo
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research (N.B., G.K., L.J.K., P.E.N., B.J.D.), The University of Western Australia, Perth.,School of Engineering (N.B., G.K., L.J.K., B.K.D.), The University of Western Australia, Perth
| | - Maaz B J Syed
- Centre for Cardiovascular Science, Queens Medical Research Institute, University of Edinburgh, United Kingdom (M.B.J.S., R.O.F., P.R.H., O.M.B.M., D.E.N., B.J.D.)
| | - Georgia Khinsoe
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research (N.B., G.K., L.J.K., P.E.N., B.J.D.), The University of Western Australia, Perth.,School of Engineering (N.B., G.K., L.J.K., B.K.D.), The University of Western Australia, Perth
| | - Lachlan J Kelsey
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research (N.B., G.K., L.J.K., P.E.N., B.J.D.), The University of Western Australia, Perth.,School of Engineering (N.B., G.K., L.J.K., B.K.D.), The University of Western Australia, Perth
| | - Rachael O Forsythe
- Centre for Cardiovascular Science, Queens Medical Research Institute, University of Edinburgh, United Kingdom (M.B.J.S., R.O.F., P.R.H., O.M.B.M., D.E.N., B.J.D.)
| | - Janet T Powell
- Vascular Surgery Research Group, Imperial College London, London, United Kingdom (J.T.P.)
| | - Peter R Hoskins
- Centre for Cardiovascular Science, Queens Medical Research Institute, University of Edinburgh, United Kingdom (M.B.J.S., R.O.F., P.R.H., O.M.B.M., D.E.N., B.J.D.).,Biomedical Engineering, Dundee University, United Kingdom (P.R.H.)
| | - Olivia M B McBride
- Centre for Cardiovascular Science, Queens Medical Research Institute, University of Edinburgh, United Kingdom (M.B.J.S., R.O.F., P.R.H., O.M.B.M., D.E.N., B.J.D.)
| | - Paul E Norman
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research (N.B., G.K., L.J.K., P.E.N., B.J.D.), The University of Western Australia, Perth.,Medical School (P.E.N., S.J.), The University of Western Australia, Perth
| | - Shirley Jansen
- Medical School (P.E.N., S.J.), The University of Western Australia, Perth.,Heart and Vascular Research Institute, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Perth, Australia (S.J.).,Department of Vascular and Endovascular Surgery, Sir Charles Gairdner Hospital, Perth, Australia (S.J.).,Curtin Medical School, Curtin University, Perth, Australia (S.J.)
| | - David E Newby
- Centre for Cardiovascular Science, Queens Medical Research Institute, University of Edinburgh, United Kingdom (M.B.J.S., R.O.F., P.R.H., O.M.B.M., D.E.N., B.J.D.)
| | - Barry J Doyle
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research (N.B., G.K., L.J.K., P.E.N., B.J.D.), The University of Western Australia, Perth.,School of Engineering (N.B., G.K., L.J.K., B.K.D.), The University of Western Australia, Perth.,Centre for Cardiovascular Science, Queens Medical Research Institute, University of Edinburgh, United Kingdom (M.B.J.S., R.O.F., P.R.H., O.M.B.M., D.E.N., B.J.D.).,Australian Research Council Centre for Personalised Therapeutics Technologies (B.J.D.)
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18
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Petersdorff-Campen KV, Dupuch MA, Magkoutas K, Meboldt M, Hierold C, Schmid Daners M. Pressure and Bernoulli-based Flow Measurement via a Tapered Inflow VAD Cannula. IEEE Trans Biomed Eng 2021; 69:1620-1629. [PMID: 34727020 DOI: 10.1109/tbme.2021.3123983] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Currently available ventricular assist devices provide continuous flow and do not adapt to the changing needs of patients. Physiological control algorithms have been proposed that adapt the pump speed based on the left ventricular pressure. However, so far, no clinically used pump can acquire this pressure. Therefore, for the validation of physiological control concepts in vivo, a system that can continuously and accurately provide the left ventricular pressure signal is needed. METHODS We demonstrate the integration of two pressure sensors into a tapered inflow cannula compatible with the HeartMate 3 (HM3) ventricular assist device. Selective laser melting was used to incorporate functional elements with a small footprint and therefore retain the geometry, function and implantability of the original cannula. The system was tested on a hybrid mock circulation system. Static and simulated physiological flow and pressure profiles were used to evaluate the combined pressure and flow sensing capabilities of the modified cannula. CONCLUSION The cannula prototypes enabled continuous pressure measurements at two points of their inner wall in the range of 100 and 200 mmHg. The developed, Bernoulli-based, two sensor model improved the accuracy of the measured simulated left ventricular pressure by eliminating the influence of flow inside the cannula. This method reduced the flow induced pressure uncertainty from up to 7.6 mmHg in single sensor measurements to 0.3 mmHg. Additionally, the two-sensor system and model enable the measurement of the blood flow through the pump with an accuracy of 0.140.04 L/min, without dedicated flow sensors.
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19
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Zaky ZA, Moustafa B, Aly AH. Plasma cell sensor using photonic crystal cavity. OPTICAL AND QUANTUM ELECTRONICS 2021; 53:591. [PMID: 34602711 PMCID: PMC8475417 DOI: 10.1007/s11082-021-03201-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 08/18/2021] [Indexed: 06/13/2023]
Abstract
The performance of one-dimensional photonic crystal for plasma cell application is studied theoretically. The geometry of the structure can detect the change in the refractive index of the plasma cells in a sample that infiltrated through the defect layer. We have obtained a variation on the resonant peak positions using the analyte defect layer with different refractive indices. The defect peak of the optimized structure is red-shifted from 2195 to 2322 nm when the refractive index of the defect layer changes from 1.3246 to 1.3634. This indicates a high sensitivity of the device (S = 3300 nm/RIU) as well as a high Q-factor (Q = 103). The proposed sensor has a great potential for biosensing applications and the detection of convalescent plasma.
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Affiliation(s)
- Zaky A. Zaky
- TH-PPM Group, Physics Department, Faculty of Sciences, Beni-Suef University, Beni-Suef, Egypt
| | - Basma Moustafa
- TH-PPM Group, Physics Department, Faculty of Sciences, Beni-Suef University, Beni-Suef, Egypt
| | - Arafa H. Aly
- TH-PPM Group, Physics Department, Faculty of Sciences, Beni-Suef University, Beni-Suef, Egypt
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20
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Aramburu J, Antón R, Rodríguez-Fraile M, Sangro B, Bilbao JI. Computational Fluid Dynamics Modeling of Liver Radioembolization: A Review. Cardiovasc Intervent Radiol 2021; 45:12-20. [PMID: 34518913 PMCID: PMC8716346 DOI: 10.1007/s00270-021-02956-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 08/25/2021] [Indexed: 12/16/2022]
Abstract
Yttrium-90 radioembolization (RE) is a widely used transcatheter intraarterial therapy for patients with unresectable liver cancer. In the last decade, computer simulations of hepatic artery hemodynamics during RE have been performed with the aim of better understanding and improving the therapy. In this review, we introduce the concept of computational fluid dynamics (CFD) modeling with a clinical perspective and we review the CFD models used to study RE from the fluid mechanics point of view. Finally, we show what CFD simulations have taught us about the hemodynamics during RE, the current capabilities of CFD simulations of RE, and we suggest some future perspectives.
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Affiliation(s)
- Jorge Aramburu
- Universidad de Navarra, TECNUN Escuela de Ingeniería, 20018, Donostia-San Sebastián, Spain.
| | - Raúl Antón
- Universidad de Navarra, TECNUN Escuela de Ingeniería, 20018, Donostia-San Sebastián, Spain.,IdiSNA, Instituto de Investigación Sanitaria de Navarra, 31008, Pamplona, Spain
| | - Macarena Rodríguez-Fraile
- IdiSNA, Instituto de Investigación Sanitaria de Navarra, 31008, Pamplona, Spain.,Department of Nuclear Medicine, Clínica Universidad de Navarra, 31008, Pamplona, Spain
| | - Bruno Sangro
- IdiSNA, Instituto de Investigación Sanitaria de Navarra, 31008, Pamplona, Spain.,Liver Unit, Clínica Universidad de Navarra and CIBEREHD, 31008, Pamplona, Spain
| | - José Ignacio Bilbao
- IdiSNA, Instituto de Investigación Sanitaria de Navarra, 31008, Pamplona, Spain.,Department of Radiology, Clínica Universidad de Navarra, 31008, Pamplona, Spain
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21
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Hertaeg MJ, Tabor RF, Routh AF, Garnier G. Pattern formation in drying blood drops. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2021; 379:20200391. [PMID: 34148412 PMCID: PMC8405133 DOI: 10.1098/rsta.2020.0391] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/12/2021] [Indexed: 05/20/2023]
Abstract
Patterns in dried droplets are commonly observed as rings left after spills of dirty water or coffee have evaporated. Patterns are also seen in dried blood droplets and the patterns have been shown to differ from patients afflicted with different medical conditions. This has been proposed as the basis for a new generation of low-cost blood diagnostics. Before these diagnostics can be widely used, the underlying mechanisms leading to pattern formation in these systems must be understood. We analyse the height profile and appearance of dispersions prepared with red blood cells (RBCs) from healthy donors. The red cell concentrations and diluent were varied and compared with simple polystyrene particle systems to identify the dominant mechanistic variables. Typically, a high concentration of non-volatile components suppresses ring formation. However, RBC suspensions display a greater volume of edge deposition when the red cell concentration is higher. This discrepancy is caused by the consolidation front halting during drying for most blood suspensions. This prevents the standard horizontal drying mechanism and leads to two clearly defined regions in final crack patterns and height profile. This article is part of a discussion meeting issue 'A cracking approach to inventing new tough materials: fracture stranger than friction'.
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Affiliation(s)
- Michael. J. Hertaeg
- BioPRIA and Department of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Rico F. Tabor
- School of Chemistry, Monash University, Clayton, Victoria 3800, Australia
| | - Alexander F. Routh
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, Cambridgeshire CB3 0AS, UK
| | - Gil Garnier
- BioPRIA and Department of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia
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22
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Mohammadi A, Bianchi L, Korganbayev S, De Landro M, Saccomandi P. Thermomechanical Modeling of Laser Ablation Therapy of Tumors: Sensitivity Analysis and Optimization of Influential Variables. IEEE Trans Biomed Eng 2021; 69:302-313. [PMID: 34181533 DOI: 10.1109/tbme.2021.3092889] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In cancer treatment, laser ablation is a promising technique used to induce localized thermal damage. Different variables influence the temperature distribution in the tissue and the resulting therapy efficacy; thus, the optimal therapy settings are required for obtaining the desired clinical outcome. In this work, thermomechanical modeling of contactless laser ablation was implemented to analyze the sensitivity of independent variables on the optimal treatment conditions. The Finite Element Method was utilized to solve the governing equations, i.e., the bioheat, mechanical deformation, and the Navier-Stokes equations. Validation of the model was evaluated by comparing experimental and simulated temperatures, which indicated high accuracy for estimating temperature. In particular, the results showed that the model is capable of estimating temperature with a good correlation factor (R=0.98) and low Mean Absolute Error (3.9 C). A sensitivity analysis based on laser irradiation time, power, beam distribution, and the blood vessel depth on temperature distribution and fraction of necrotic tissue was performed. Based on the most significant variables i.e., laser irradiation time and power, an optimization process was performed. This resulted into an indication of the optimal therapy settings for achieving maximum procedure efficiency i.e., the required fraction of necrotic tissue within the target volume, constituted by tumor and safety margins around it.
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23
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A Computational Analysis of the Influence of a Pressure Wire in Evaluating Coronary Stenosis. FLUIDS 2021. [DOI: 10.3390/fluids6040165] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cardiovascular disease is one of the world’s leading causes of morbidity and mortality. Fractional flow reserve (FFR) was proposed in the 1990s to more accurately evaluate the functional severity of intermediate coronary stenosis, and it is currently the gold standard in cardiac catheterization laboratories where coronary pressure and flow are routinely obtained. The clinical measurement of FFR relies on a pressure wire for the recording of pressures; however, in computational fluid dynamics studies, an FFR is frequently predicted using a wire-absent model. We aim to investigate the influence of the physical presence of a 0.014-inch (≈0.36 mm) pressure wire in the calculation of virtual FFR. Ideal and patient-specific models were simulated with the absence and presence of a pressure wire. The computed FFR reduced from 0.96 to 0.93 after inserting a wire in a 3-mm non-stenosed (pipe) ideal model. In mild stenotic cases, the difference in FFR between the wire-absent and wire-included models was slight. The overestimation in severe case was large but is of less clinical significance because, in practice, this tight lesion does not require sophisticated measurement to be considered critical. However, an absence of the pressure wire in simulations could contribute to an over-evaluation for an intermediate coronary stenosis.
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24
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CFD Simulations of Radioembolization: A Proof-of-Concept Study on the Impact of the Hepatic Artery Tree Truncation. MATHEMATICS 2021. [DOI: 10.3390/math9080839] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Radioembolization (RE) is a treatment for patients with liver cancer, one of the leading cause of cancer-related deaths worldwide. RE consists of the transcatheter intraarterial infusion of radioactive microspheres, which are injected at the hepatic artery level and are transported in the bloodstream, aiming to target tumors and spare healthy liver parenchyma. In paving the way towards a computer platform that allows for a treatment planning based on computational fluid dynamics (CFD) simulations, the current simulation (model preprocess, model solving, model postprocess) times (of the order of days) make the CFD-based assessment non-viable. One of the approaches to reduce the simulation time includes the reduction in size of the simulated truncated hepatic artery. In this study, we analyze for three patient-specific hepatic arteries the impact of reducing the geometry of the hepatic artery on the simulation time. Results show that geometries can be efficiently shortened without impacting greatly on the microsphere distribution.
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25
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Efficacy of New Zeolite-Based Hemostatic Gauze in a Gunshot Model of Junctional Femoral Artery Hemorrhage in Swine. J Surg Res 2021; 263:176-185. [PMID: 33676113 DOI: 10.1016/j.jss.2020.12.040] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 11/11/2020] [Accepted: 12/16/2020] [Indexed: 11/21/2022]
Abstract
BACKGROUND This work sought to (1) establish a reliable gunshot model of junctional femoral artery rupture in swine that accurately simulates field rescue conditions and (2) use the gunshot model to compare the efficacy and ease of application of zeolite nanometer hemostatic gauze with other hemostatic materials. METHODS Thirty-six healthy landrace swine (body weight 50 ± 5 kg) were randomly divided into three groups which were treated with Combat Gauze (CG), FeiChuang hemostatic gauze (FG), or standard medical gauze (SG). A gunshot model of femoral artery hemorrhage in landrace swine was used with portable ultrasound to accurately position the wound. After the shooting, when mean arterial pressure of swine decreased by at least 30% for 10 s, wounds were pressed with standard packing (39 g) of gauze materials for 3 min to stop bleeding, then bandaged with pressure. Blood samples were taken 15 min before injury, then 10 min, 30 min, and 60 min after injury to determine hemodynamic, coagulation, and arterial blood gas indexes. Wound temperatures were taken at 5 min, 10 min, 30 min, and 60 min after injury, and survival times were recorded. The volume of blood loss and survival time were used to evaluate hemostatic effect, whereas the fill time, wound temperature, and physiological indexes were used to evaluate the safety and operation of the product. RESULTS The CG (11.15 ± 3.09 mL/kg) and FG (12.19 ± 3.5 mL/kg) groups had significantly less blood loss than the SG group (16.8 ± 5.14 mL/kg) (P = 0.04; P = 0.039, respectively). After gauze packing, bleeding in CG (5.85 ± 1.17 mL/kg) and FG (5.37 ± 0.93 mL/kg) groups remained significantly lower than that of the SG group (6.93 ± 1.03 mL/kg) (P = 0.011; P = 0.003, respectively). Wound temperature rose with time for all groups (P < 0.001). The wound temperatures in the FG group and the CG group were significantly higher than that of the SG group (P = 004 and 0.009, respectively). Survival rates and times were not significantly different among the three groups, although the FG group had the longest average survival time (standard deviation [SD] 204.8 s), compared with the SG group (SD 177.8 s) and CG (SD 187.5 s) groups. No significant differences in hemodynamics, blood gas, and coagulation were observed among the three groups. CONCLUSIONS The gunshot model of junctional femoral arterial hemorrhage guided by ultrasound had high accuracy for femoral arterial rupture by bullet wound and provided consistent and reproducible field-simulation conditions for comparison of hemostatic materials. FeiChuang zeolite hemostatic gauze effectively controlled bleeding as well as combat gauze, without excessive heat as found in other zeolite-based products. However, improvements to application technique, such as a packing device, are needed to improve operating time.
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26
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Orr A, Gualdieri R, Cossette ML, Shafer ABA, Stotesbury T. Whole bovine blood use in forensic research: Sample preparation and storage considerations. Sci Justice 2021; 61:214-220. [PMID: 33985669 DOI: 10.1016/j.scijus.2021.02.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 02/18/2021] [Accepted: 02/21/2021] [Indexed: 10/22/2022]
Abstract
Mammalian whole blood sources are often used for forensic research and training when human samples cannot be sourced. While porcine, ovine and equine blood have been shown to be viable alternatives to whole human blood for forensic purposes, procurement can still pose a problem, especially for smaller and remote institutions. This work explores the use of whole bovine blood for basic bloodstain simulation. Sample preparation through the addition of ACD-A anticoagulant was optimized and storability was explored. Viscosity, surface tension, density, and packed cell volume, four fluid properties relevant to bloodstain pattern analysis, were monitored over four days and in two temperature conditions. Linear mixed models accounting for variation in the donor demonstrated that these fluid properties of the bovine blood changed predictably over time and with temperature. Whole bovine blood with 12.5% v/v ACD-A was found to be viable for use in basic bloodstain simulation at ambient and physiological temperature.
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Affiliation(s)
- Amanda Orr
- Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON K9L 0G2, Canada
| | - Rebecca Gualdieri
- Forensic Science Undergraduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON K9L 0G2, Canada
| | - Marie-Laurence Cossette
- Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON K9L 0G2, Canada; Forensic Science Undergraduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON K9L 0G2, Canada
| | - Aaron B A Shafer
- Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON K9L 0G2, Canada; Forensic Science Undergraduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON K9L 0G2, Canada
| | - Theresa Stotesbury
- Forensic Science Undergraduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON K9L 0G2, Canada; Faculty of Science, Forensic Science, Ontario Tech University, 2000 Simcoe St N, Oshawa, ON L1G 0C5, Canada.
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Xu F, Johnson EL, Wang C, Jafari A, Yang CH, Sacks MS, Krishnamurthy A, Hsu MC. Computational investigation of left ventricular hemodynamics following bioprosthetic aortic and mitral valve replacement. MECHANICS RESEARCH COMMUNICATIONS 2021; 112:103604. [PMID: 34305195 PMCID: PMC8301225 DOI: 10.1016/j.mechrescom.2020.103604] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The left ventricle of the heart is a fundamental structure in the human cardiac system that pumps oxygenated blood into the systemic circulation. Several valvular conditions can cause the aortic and mitral valves associated with the left ventricle to become severely diseased and require replacement. However, the clinical outcomes of such operations, specifically the postoperative ventricular hemodynamics of replacing both valves, are not well understood. This work uses computational fluid-structure interaction (FSI) to develop an improved understanding of this effect by modeling a left ventricle with the aortic and mitral valves replaced with bioprostheses. We use a hybrid Arbitrary Lagrangian-Eulerian/immersogeometric framework to accommodate the analysis of cardiac hemodynamics and heart valve structural mechanics in a moving fluid domain. The motion of the endocardium is obtained from a cardiac biomechanics simulation and provided as an input to the proposed numerical framework. The results from the simulations in this work indicate that the replacement of the native mitral valve with a tri-radially symmetric bioprosthesis dramatically changes the ventricular hemodynamics. Most significantly, the vortical motion in the left ventricle is found to reverse direction after mitral valve replacement. This study demonstrates that the proposed computational FSI framework is capable of simulating complex multiphysics problems and can provide an in-depth understanding of the cardiac mechanics.
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Affiliation(s)
- Fei Xu
- Ansys Inc., Austin, TX 78746, USA
| | - Emily L. Johnson
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA
| | | | - Arian Jafari
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA
| | - Cheng-Hau Yang
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA
| | - Michael S. Sacks
- Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, TX 78712, USA
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA
| | - Adarsh Krishnamurthy
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA
| | - Ming-Chen Hsu
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA
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28
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Bateman AR, Bateman GA, Barber T. The relationship between cerebral blood flow and venous sinus pressure: can hyperemia induce idiopathic intracranial hypertension? Fluids Barriers CNS 2021; 18:5. [PMID: 33541388 PMCID: PMC7860203 DOI: 10.1186/s12987-021-00239-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 01/16/2021] [Indexed: 01/06/2023] Open
Abstract
Background It has been shown that idiopathic intracranial hypertension (IIH) in children is associated with cerebral hyperemia, which induces an increase in cerebral venous pressure. The current literature suggests venous pressure scales with blood flow in a linear fashion, however, a linear relationship would not raise the pressure high enough to induce IIH. There is, however, some evidence to suggest that this relationship could be quadratic in nature. The purpose of this paper is to characterize the relationship between cerebral blood flow and the pressure drop across the cerebral venous system. Methods 10 CT venogram data sets were collected for this study, with 5 useable geometries created. Computational fluid dynamics (CFD) models were generated using these geometries, with 10 simulations conducted per patient. The flow rates tested ranged from 200 mL/min to 2000 mL/min. 3D pressure and velocity streamline distributions were created and analyzed for each CFD model, with pressure drops across the cerebral venous system determined. The effective and hydraulic diameters were determined at the superior sagittal sinus, transverse sinus and both proximal and distal sigmoid sinuses. Results A quadratic relationship between blood flow and sinus pressure was found, with correlations of 0.99 or above in all five patients. The presence of vortical blood flow was found to explain this trend, with fluid curl and pressure drop correlations being above 0.97. This suggests that the presence of high blood flow should be considered in the diagnostic workup of IIH. Conclusions The cerebral venous sinus blood flow and pressure response relationship are quadratic in nature, with the major cause of this being the degree of rotation induced in the flow. The elevated blood flow found in children with IIH can explain the increased ICP that is found, secondary to the increase in venous pressure that develops.
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Affiliation(s)
- Alexander Robert Bateman
- School of Mechanical Engineering, University of New South Wales, Library Rd, Kensington, NSW, 2052, Australia.
| | - Grant Alexander Bateman
- Department of Medical Imaging, John Hunter Hospital, Newcastle, NSW, Australia.,Newcastle University Faculty of Health, Callaghan Campus, Newcastle, NSW, Australia
| | - Tracie Barber
- School of Mechanical Engineering, University of New South Wales, Library Rd, Kensington, NSW, 2052, Australia
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29
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Basil-Kway V, Castillo-Reyther R, Domínguez-Salgado LA, Espinosa-Tanguma R, Medina Ú, Gordillo-Moscoso A. Early prognostic capacity of serum lactate for severe postpartum hemorrhage. Int J Gynaecol Obstet 2020; 153:483-488. [PMID: 33119891 DOI: 10.1002/ijgo.13446] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 07/23/2020] [Accepted: 10/27/2020] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To evaluate whether the concentration of serum lactate during the diagnosis of postpartum hemorrhage (bleeding ≥500 mL during labor or ≥1000 mL during cesarean delivery) predicts severe hemorrhage (SPPH; blood loss ≥1500 mL at end of labor or in the following 24 h). METHODS A prospective cohort pilot study was conducted of women with a vaginal or cesarean delivery from February 2018 to March 2019 who presented with bleeding ≥500 mL measured by the gravimetric method in a reference hospital in San Luis Potosi, Mexico. Venous blood samples were taken for analysis of serum lactate. A receiver operating characteristic curve determined the serum lactate threshold value for SPPH and χ2 test assessed the difference in serum lactate elevation between SPPH and non-SPPH groups. Lastly, the prognostic capacity between the thresholds was compared. RESULTS SPPH developed in 43.33% of the 30 women in the study group. The best prognostic threshold was 2.68 mmol/L of serum lactate (odds ratio [OR] 17.88, 95% confidence interval [CI] 2.7-16.8, P < 0.001); sensitivity was 0.85 (95% CI 0.55-0.98); specificity was 0.76 (95% CI 0.50-0.93). CONCLUSION Serum lactate may be a useful prognostic marker for SPPH, more studies are needed to validate these findings.
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Affiliation(s)
- Venance Basil-Kway
- Department of Clinical Epidemiology, School of Medicine, Universidad Autonoma de San Luis Potosi, San Luis Potosi, Mexico
| | - Roberto Castillo-Reyther
- Department of Obstetrics and Gynecology, Hospital Central Dr. Ignacio Morones Prieto, San Luis Potosi, Mexico.,School of Medicine, Universidad Autonoma de San Luis Potosi, San Luis Potosi, Mexico
| | - L Andrés Domínguez-Salgado
- Department of Clinical Epidemiology, School of Medicine, Universidad Autonoma de San Luis Potosi, San Luis Potosi, Mexico
| | - Ricardo Espinosa-Tanguma
- Department of Physiology, School of Medicine, Universidad Autonoma de San Luis Potosi, San Luis Potosi, Mexico
| | - Úrsula Medina
- Department of Clinical Epidemiology, School of Medicine, Universidad Autonoma de San Luis Potosi, San Luis Potosi, Mexico.,Department of Pharmacology, School of Medicine, Universidad Autonoma de San Luis Potosi, San Luis Potosi, Mexico
| | - Antonio Gordillo-Moscoso
- Department of Clinical Epidemiology, School of Medicine, Universidad Autonoma de San Luis Potosi, San Luis Potosi, Mexico
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30
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Wallnöfer EA, Thurner GC, Kremser C, Talasz H, Stollenwerk MM, Helbok A, Klammsteiner N, Albrecht-Schgoer K, Dietrich H, Jaschke W, Debbage P. Albumin-based nanoparticles as contrast medium for MRI: vascular imaging, tissue and cell interactions, and pharmacokinetics of second-generation nanoparticles. Histochem Cell Biol 2020; 155:19-73. [PMID: 33040183 DOI: 10.1007/s00418-020-01919-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2020] [Indexed: 12/14/2022]
Abstract
This multidisciplinary study examined the pharmacokinetics of nanoparticles based on albumin-DTPA-gadolinium chelates, testing the hypothesis that these nanoparticles create a stronger vessel signal than conventional gadolinium-based contrast agents and exploring if they are safe for clinical use. Nanoparticles based on human serum albumin, bearing gadolinium and designed for use in magnetic resonance imaging, were used to generate magnet resonance images (MRI) of the vascular system in rats ("blood pool imaging"). At the low nanoparticle doses used for radionuclide imaging, nanoparticle-associated metals were cleared from the blood into the liver during the first 4 h after nanoparticle application. At the higher doses required for MRI, the liver became saturated and kidney and spleen acted as additional sinks for the metals, and accounted for most processing of the nanoparticles. The multiple components of the nanoparticles were cleared independently of one another. Albumin was detected in liver, spleen, and kidneys for up to 2 days after intravenous injection. Gadolinium was retained in the liver, kidneys, and spleen in significant concentrations for much longer. Gadolinium was present as significant fractions of initial dose for longer than 2 weeks after application, and gadolinium clearance was only complete after 6 weeks. Our analysis could not account quantitatively for the full dose of gadolinium that was applied, but numerous organs were found to contain gadolinium in the collagen of their connective tissues. Multiple lines of evidence indicated intracellular processing opening the DTPA chelates and leading to gadolinium long-term storage, in particular inside lysosomes. Turnover of the stored gadolinium was found to occur in soluble form in the kidneys, the liver, and the colon for up to 3 weeks after application. Gadolinium overload poses a significant hazard due to the high toxicity of free gadolinium ions. We discuss the relevance of our findings to gadolinium-deposition diseases.
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Affiliation(s)
- E A Wallnöfer
- Department of Radiology, Medical University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria
| | - G C Thurner
- Department of Radiology, Medical University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria
- Division of Histology and Embryology, Department of Anatomy, Histology and Embryology, Medical University of Innsbruck, Müllerstrasse 59, 6020, Innsbruck, Austria
| | - C Kremser
- Department of Radiology, Medical University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria
| | - H Talasz
- Division of Clinical Biochemistry, Biocenter, Medical University of Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria
| | - M M Stollenwerk
- Faculty of Health and Society, Biomedical Laboratory Science, University Hospital MAS, Malmö University, 205 06, Malmö, Sweden
- Division of Histology and Embryology, Department of Anatomy, Histology and Embryology, Medical University of Innsbruck, Müllerstrasse 59, 6020, Innsbruck, Austria
| | - A Helbok
- Department of Nuclear Medicine, Innsbruck Medical University, Anichstrasse 35, 6020, Innsbruck, Austria
| | - N Klammsteiner
- Division of Histology and Embryology, Department of Anatomy, Histology and Embryology, Medical University of Innsbruck, Müllerstrasse 59, 6020, Innsbruck, Austria
| | - K Albrecht-Schgoer
- Department of Pharmaceutical Technology, Institute of Pharmacy, Leopold-Franzens-University Innsbruck, Innrain 80-82/IV, 6020, Innsbruck, Austria
- Institute of Cell Genetics, Department for Pharmacology and Genetics, Medical University of Innsbruck, Peter-Mayr-Strasse 1a, 6020, Innsbruck, Austria
| | - H Dietrich
- Central Laboratory Animal Facilities, Innsbruck Medical University, Peter-Mayr-Strasse 4a, 6020, Innsbruck, Austria
| | - W Jaschke
- Department of Radiology, Medical University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria
| | - P Debbage
- Division of Histology and Embryology, Department of Anatomy, Histology and Embryology, Medical University of Innsbruck, Müllerstrasse 59, 6020, Innsbruck, Austria.
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31
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Ge S, Nemiroski A, Mirica KA, Mace CR, Hennek JW, Kumar AA, Whitesides GM. Magnetic Levitation in Chemistry, Materials Science, and Biochemistry. Angew Chem Int Ed Engl 2020; 59:17810-17855. [PMID: 31165560 DOI: 10.1002/anie.201903391] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Indexed: 12/25/2022]
Abstract
All matter has density. The recorded uses of density to characterize matter date back to as early as ca. 250 BC, when Archimedes was believed to have solved "The Puzzle of The King's Crown" using density.[1] Today, measurements of density are used to separate and characterize a range of materials (including cells and organisms), and their chemical and/or physical changes in time and space. This Review describes a density-based technique-magnetic levitation (which we call "MagLev" for simplicity)-developed and used to solve problems in the fields of chemistry, materials science, and biochemistry. MagLev has two principal characteristics-simplicity, and applicability to a wide range of materials-that make it useful for a number of applications (for example, characterization of materials, quality control of manufactured plastic parts, self-assembly of objects in 3D, separation of different types of biological cells, and bioanalyses). Its simplicity and breadth of applications also enable its use in low-resource settings (for example-in economically developing regions-in evaluating water/food quality, and in diagnosing disease).
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Affiliation(s)
- Shencheng Ge
- Department of Chemistry & Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA, 02138, USA
| | - Alex Nemiroski
- Department of Chemistry & Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA, 02138, USA
| | - Katherine A Mirica
- Department of Chemistry & Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA, 02138, USA
| | - Charles R Mace
- Department of Chemistry & Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA, 02138, USA
| | - Jonathan W Hennek
- Department of Chemistry & Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA, 02138, USA
| | - Ashok A Kumar
- Department of Chemistry & Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA, 02138, USA
| | - George M Whitesides
- Department of Chemistry & Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA, 02138, USA.,Wyss Institute for Biologically Inspired Engineering, Harvard University, 60 Oxford Street, Cambridge, MA, 02138, USA.,Kavli Institute for Bionano Science & Technology, Harvard University, 29 Oxford Street, Cambridge, MA, 02138, USA
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32
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Ge S, Nemiroski A, Mirica KA, Mace CR, Hennek JW, Kumar AA, Whitesides GM. Magnetische Levitation in Chemie, Materialwissenschaft und Biochemie. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201903391] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Shencheng Ge
- Department of Chemistry & Chemical Biology Harvard University 12 Oxford Street Cambridge MA 02138 USA
| | - Alex Nemiroski
- Department of Chemistry & Chemical Biology Harvard University 12 Oxford Street Cambridge MA 02138 USA
| | - Katherine A. Mirica
- Department of Chemistry & Chemical Biology Harvard University 12 Oxford Street Cambridge MA 02138 USA
| | - Charles R. Mace
- Department of Chemistry & Chemical Biology Harvard University 12 Oxford Street Cambridge MA 02138 USA
| | - Jonathan W. Hennek
- Department of Chemistry & Chemical Biology Harvard University 12 Oxford Street Cambridge MA 02138 USA
| | - Ashok A. Kumar
- Department of Chemistry & Chemical Biology Harvard University 12 Oxford Street Cambridge MA 02138 USA
| | - George M. Whitesides
- Department of Chemistry & Chemical Biology Harvard University 12 Oxford Street Cambridge MA 02138 USA
- Wyss Institute for Biologically Inspired Engineering Harvard University 60 Oxford Street Cambridge MA 02138 USA
- Kavli Institute for Bionano Science & Technology Harvard University 29 Oxford Street Cambridge MA 02138 USA
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33
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Aramburu J, Antón R, Rivas A, Ramos JC, Sangro B, Bilbao JI. Liver Radioembolization: An Analysis of Parameters that Influence the Catheter-Based Particle-Delivery via CFD. Curr Med Chem 2020; 27:1600-1615. [DOI: 10.2174/0929867325666180622145647] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 05/18/2017] [Accepted: 05/25/2017] [Indexed: 12/13/2022]
Abstract
Radioembolization (RE) is a valuable treatment for liver cancer. It consists of administering
radioactive microspheres by an intra-arterially placed catheter with the aim of
lodging these microspheres, which are driven by the bloodstream, in the tumoral bed. Even
though it is a safe treatment, some radiation-induced complications may arise. In trying to
detect or solve the possible incidences that cause nontarget irradiation, simulating the particle-
hemodynamics in hepatic arteries during RE by computational fluid dynamics (CFD)
tools has become a valuable approach. This paper reviews the parameters that influence the
outcome of RE and that have been studied via numerical simulations. In this numerical approach,
the outcome of RE is regarded as successful if particles reach the artery branches that
feed tumor-bearing liver segments. Up to 10 parameters have been reviewed. The variation
of each parameter actually alters the hemodynamic pattern in the vicinities of the catheter tip
and locally alters the incorporation of the particles into the bloodstream. Therefore, in general,
the local influences of these parameters should result in global differences in terms of
particle distribution in the hepatic artery branches. However, it has been observed that under
some (qualitatively described) appropriate conditions where particles align with blood
streamlines, the local influence resulting from a variation of a given parameter vanishes and
no global differences are observed. Furthermore, the increasing number of CFD studies on
RE suggests that numerical simulations have become an invaluable research tool in the study
of RE.
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Affiliation(s)
- Jorge Aramburu
- Universidad de Navarra, TECNUN Escuela de Ingenieros, 20018 Donostia-San Sebastian, Spain
| | - Raúl Antón
- Universidad de Navarra, TECNUN Escuela de Ingenieros, 20018 Donostia-San Sebastian, Spain
| | - Alejandro Rivas
- Universidad de Navarra, TECNUN Escuela de Ingenieros, 20018 Donostia-San Sebastian, Spain
| | - Juan C. Ramos
- Universidad de Navarra, TECNUN Escuela de Ingenieros, 20018 Donostia-San Sebastian, Spain
| | - Bruno Sangro
- IdiSNA, Instituto de Investigacion Sanitaria de Navarra, 31008 Pamplona, Spain
| | - José I. Bilbao
- IdiSNA, Instituto de Investigacion Sanitaria de Navarra, 31008 Pamplona, Spain
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34
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Shipley RJ, Sweeney PW, Chapman SJ, Roose T. A four-compartment multiscale model of fluid and drug distribution in vascular tumours. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2020; 36:e3315. [PMID: 32031302 PMCID: PMC7187161 DOI: 10.1002/cnm.3315] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Revised: 11/29/2019] [Accepted: 01/17/2020] [Indexed: 06/10/2023]
Abstract
The subtle relationship between vascular network structure and mass transport is vital to predict and improve the efficacy of anticancer treatments. Here, mathematical homogenisation is used to derive a new multiscale continuum model of blood and chemotherapy transport in the vasculature and interstitium of a vascular tumour. This framework enables information at a range of vascular hierarchies to be fed into an effective description on the length scale of the tumour. The model behaviour is explored through a demonstrative case study of a simplified representation of a dorsal skinfold chamber, to examine the role of vascular network architecture in influencing fluid and drug perfusion on the length scale of the chamber. A single parameter, P, is identified that relates tumour-scale fluid perfusion to the permeability and density of the capillary bed. By fixing the topological and physiological properties of the arteriole and venule networks, an optimal value for P is identified, which maximises tumour fluid transport and is thus hypothesised to benefit chemotherapy delivery. We calculate the values for P for eight explicit network structures; in each case, vascular intervention by either decreasing the permeability or increasing the density of the capillary network would increase fluid perfusion through the cancerous tissue. Chemotherapeutic strategies are compared and indicate that single injection is consistently more successful compared with constant perfusion, and the model predicts optimal timing of a second dose. These results highlight the potential of computational modelling to elucidate the link between vascular architecture and fluid, drug distribution in tumours.
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Affiliation(s)
| | - Paul W. Sweeney
- Department of Mechanical EngineeringUniversity College LondonLondonUK
| | - Stephen J. Chapman
- Oxford Centre for Industrial and Applied MathematicsMathematical InstituteOxfordUK
| | - Tiina Roose
- School of Engineering Sciences, Faculty of Engineering and Physical SciencesUniversity of SouthamptonSouthamptonUK
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35
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Rikkert LG, van der Pol E, van Leeuwen TG, Nieuwland R, Coumans FAW. Centrifugation affects the purity of liquid biopsy-based tumor biomarkers. Cytometry A 2019; 93:1207-1212. [PMID: 30551256 PMCID: PMC6590195 DOI: 10.1002/cyto.a.23641] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 09/28/2018] [Accepted: 10/01/2018] [Indexed: 01/05/2023]
Abstract
Biomarkers in the blood of cancer patients include circulating tumor cells (CTCs), tumor-educated platelets (TEPs), tumor-derived extracellular vesicles (tdEVs), EV-associated miRNA (EV-miRNA), and circulating cell-free DNA (ccfDNA). Because the size and density of biomarkers differ, blood is centrifuged to isolate or concentrate the biomarker of interest. Here, we applied a model to estimate the effect of centrifugation on the purity of a biomarker according to published protocols. The model is based on the Stokes equation and was validated using polystyrene beads in buffer and plasma. Next, the model was applied to predict the biomarker behavior during centrifugation. The result was expressed as the recovery of CTCs, TEPs, tdEVs in three size ranges (1-8, 0.2-1, and 0.05-0.2 μm), EV-miRNA, and ccfDNA. Bead recovery was predicted with errors <18%. Most notable cofounders are the 22% contamination of 1-8 μm tdEVs for TEPs and the 8-82% contamination of <1 μm tdEVs for ccfDNA. A Stokes model can predict biomarker behavior in blood. None of the evaluated protocols produces a pure biomarker. Thus, care should be taken in the interpretation of obtained results, as, for example, results from TEPs may originate from co-isolated large tdEVs and ccfDNA may originate from DNA enclosed in <1 μm tdEVs. © 2018 The Authors. Cytometry Part A published by Wiley Periodicals, Inc. on behalf of International Society for Advancement of Cytometry.
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Affiliation(s)
- Linda G Rikkert
- Medical Cell BioPhysics, University of Twente, Enschede, the Netherlands.,Amsterdam UMC, University of Amsterdam, Laboratory of Experimental Clinical Chemistry, Amsterdam, the Netherlands.,Amsterdam UMC, University of Amsterdam, Vesicle Observation Center, Amsterdam, the Netherlands
| | - Edwin van der Pol
- Amsterdam UMC, University of Amsterdam, Vesicle Observation Center, Amsterdam, the Netherlands.,Amsterdam UMC, University of Amsterdam, Biomedical Engineering and Physics, Amsterdam, the Netherlands
| | - Ton G van Leeuwen
- Amsterdam UMC, University of Amsterdam, Vesicle Observation Center, Amsterdam, the Netherlands.,Amsterdam UMC, University of Amsterdam, Biomedical Engineering and Physics, Amsterdam, the Netherlands
| | - Rienk Nieuwland
- Amsterdam UMC, University of Amsterdam, Laboratory of Experimental Clinical Chemistry, Amsterdam, the Netherlands.,Amsterdam UMC, University of Amsterdam, Vesicle Observation Center, Amsterdam, the Netherlands
| | - Frank A W Coumans
- Amsterdam UMC, University of Amsterdam, Laboratory of Experimental Clinical Chemistry, Amsterdam, the Netherlands.,Amsterdam UMC, University of Amsterdam, Vesicle Observation Center, Amsterdam, the Netherlands
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36
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Ortiz-Santaliestra ME, Rodríguez A, Pareja-Carrera J, Mateo R, Martinez-Haro M. Tools for non-invasive sampling of metal accumulation and its effects in Mediterranean pond turtle populations inhabiting mining areas. CHEMOSPHERE 2019; 231:194-206. [PMID: 31129400 DOI: 10.1016/j.chemosphere.2019.05.082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 05/10/2019] [Accepted: 05/11/2019] [Indexed: 06/09/2023]
Abstract
Among reptiles, freshwater turtle species have high potential for metal accumulation because of their long lifespan or their aquatic and terrestrial habits. In order to monitor metal bioaccumulation, determine potential toxic effects, and investigate tools for non-invasive metal sampling in reptiles, we studied lead (Pb) and mercury (Hg) accumulation in Mediterranean pond turtles (Mauremys leprosa) inhabiting two former mining areas, one of them with high environmental concentrations of Pb (Sierra Madrona-Alcudia Valley district) and the other one with high environmental concentrations of Hg (Almadén district). Individuals from the Pb mining area showed mean blood concentrations (i.e. 5.59 μg Pb/g dry weight, d.w.) that were higher than those measured in other populations. Blood Hg concentrations were highest (8.83 μg Hg/g d.w.) in the site close to the former Hg mines, whereas blood Hg concentrations in terrapins from another site of Almadén district, located ∼28 km downstream, were not different from locations at the non-mining area. Animals from the Pb-contaminated site showed evidence of oxidative stress, whereas those from the Hg-contaminated site showed increased activity of the antioxidant enzyme glutathione peroxidase, as well as reduced circulating levels of the main endogenous antioxidant peptide, glutathione. Concentrations measured in feces and carapace scutes were useful indicators to monitor blood concentrations of Pb, but not of Hg. Our results provide evidence of the usefulness of freshwater turtles as sentinels of chronic metal pollution, and validate non-invasive tools to advance Pb monitoring in reptiles.
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Affiliation(s)
- Manuel E Ortiz-Santaliestra
- Instituto de Investigación en Recursos Cinegéticos (IREC) CSIC-UCLM-JCCM. Ronda de Toledo 12, 13005, Ciudad Real, Spain.
| | - Antonio Rodríguez
- Instituto de Investigación en Recursos Cinegéticos (IREC) CSIC-UCLM-JCCM. Ronda de Toledo 12, 13005, Ciudad Real, Spain.
| | - Jennifer Pareja-Carrera
- Instituto de Investigación en Recursos Cinegéticos (IREC) CSIC-UCLM-JCCM. Ronda de Toledo 12, 13005, Ciudad Real, Spain.
| | - Rafael Mateo
- Instituto de Investigación en Recursos Cinegéticos (IREC) CSIC-UCLM-JCCM. Ronda de Toledo 12, 13005, Ciudad Real, Spain.
| | - Mónica Martinez-Haro
- Instituto de Investigación en Recursos Cinegéticos (IREC) CSIC-UCLM-JCCM. Ronda de Toledo 12, 13005, Ciudad Real, Spain.
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37
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Gimnich OA, Singh J, Bismuth J, Shah DJ, Brunner G. Magnetic resonance imaging based modeling of microvascular perfusion in patients with peripheral artery disease. J Biomech 2019; 93:147-158. [PMID: 31331663 PMCID: PMC7390497 DOI: 10.1016/j.jbiomech.2019.06.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 06/25/2019] [Accepted: 06/26/2019] [Indexed: 11/20/2022]
Abstract
Peripheral artery disease (PAD) is associated with an increased risk of adverse cardiovascular events, impaired lower extremity blood flow and microvascular perfusion abnormalities in the calf muscles which can be determined with contrast-enhanced magnetic resonance imaging (CE-MRI). We developed a computational model of the microvascular perfusion in the calf muscles. We included 20 patients (10 PAD, 10 controls) and utilized the geometry, mean signal intensity and arterial input functions from CE-MRI calf muscle perfusion scans. The model included the microvascular pressure (pv), outflow filtration coefficient (OFC), transfer rate constant (kt), porosity (φ), and the interstitial permeability (Ktissue). Parameters were fitted and the simulations were compared across PAD patients and controls. Intra-observer reproducibility of the simulated mean signal intensities was excellent (intraclass correlation coefficients >0.995). kt and Ktissue were higher in PAD patients compared with controls (4.72 interquartile range (IQR) 3.33, 5.56 vs. 2.47 IQR 2.10, 2.85; p = 0.003; and 3.68 IQR 3.18, 4.41 vs. 1.81 IQR 1.81, 1.81; p < 0.001). Conversely, porosity (φ) was lower in PAD patients compared with controls (0.52 IQR 0.49, 0.54 vs. 0.61 IQR 0.58, 0.64; p = 0.016). Porosity (φ) was correlated with the ankle brachial index (r = 0.64, p = 0.011). The proposed computational microvascular model is robust and reproducible, and essential model parameters differ significantly between PAD patients and controls.
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Affiliation(s)
- Olga A Gimnich
- Cardiovascular Imaging Research and Data Sciences Laboratory, Department of Medicine, Baylor College of Medicine, Houston, TX, USA; Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Jaykrishna Singh
- Methodist DeBakey Heart and Vascular Center, Houston Methodist Hospital, Houston, TX, USA
| | - Jean Bismuth
- Methodist DeBakey Heart and Vascular Center, Houston Methodist Hospital, Houston, TX, USA
| | - Dipan J Shah
- Methodist DeBakey Heart and Vascular Center, Houston Methodist Hospital, Houston, TX, USA
| | - Gerd Brunner
- Cardiovascular Imaging Research and Data Sciences Laboratory, Department of Medicine, Baylor College of Medicine, Houston, TX, USA; Methodist DeBakey Heart and Vascular Center, Houston Methodist Hospital, Houston, TX, USA; Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA, USA..
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Qiao Y, Fan J, Ding Y, Zhu T, Luo K. A Primary Computational Fluid Dynamics Study of Pre- and Post-TEVAR With Intentional Left Subclavian Artery Coverage in a Type B Aortic Dissection. J Biomech Eng 2019; 141:2735390. [DOI: 10.1115/1.4043881] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Indexed: 11/08/2022]
Abstract
The impact of left subclavian artery (LSA) coverage during thoracic endovascular aortic repair (TEVAR) on the circulatory system is not fully understood. Here, we coupled a single-phase non-Newtonian model with fluid–structure interaction (FSI) technique to simulate blood flow in an acute type B aortic dissection. Three-element Windkessel model was implemented to reproduce physiological pressure waves, where a new workflow was designed to determine model parameters with the absence of measured data. Simulations were carried out in three geometric models to demonstrate the consequence of TEVAR with the LSA coverage; case A: pre-TEVAR aorta; case B: post-TEVAR aorta with the disappearance of LSA; case C: post-TEVAR aorta with virtually adding LSA. Results show that the blood flow through the compressed true lumen is only 8.43%, which may lead to ischemia in related organs. After TEVAR, the wall pressure on the stented segment increases and blood flow in the supra-aortic branches and true lumen is improved. Meantime, the average deformation of the aorta is obviously reduced due to the implantation of the stent graft. After virtually adding LSA, significant changes in the distribution of blood flow and two indices based on wall shear stress are observed. Moreover, the movement of residual false lumen becomes stable, which could contribute to patient recovery. Overall, this study quantitatively evaluates the efficacy of TEVAR for acute type B aortic dissection and demonstrates that the coverage of LSA has a considerable impact on the important hemodynamic parameters.
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Affiliation(s)
- Yonghui Qiao
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, 38 Zheda Road, Hangzhou 310027, China e-mail:
| | - Jianren Fan
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, 38 Zheda Road, Hangzhou 310027, China e-mail:
| | - Ying Ding
- Department of Radiology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China e-mail:
| | - Ting Zhu
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China e-mail:
| | - Kun Luo
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, 38 Zheda Road, Hangzhou 310027, China e-mail:
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A predictive computational model to estimate myocardial temperature during intracoronary hypothermia in acute myocardial infarction. Med Eng Phys 2019; 68:65-75. [DOI: 10.1016/j.medengphy.2019.03.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 03/15/2019] [Accepted: 03/31/2019] [Indexed: 11/20/2022]
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40
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Finlayson KA, Leusch FDL, van de Merwe JP. Cytotoxicity of organic and inorganic compounds to primary cell cultures established from internal tissues of Chelonia mydas. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 664:958-967. [PMID: 30769319 DOI: 10.1016/j.scitotenv.2019.02.052] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 01/30/2019] [Accepted: 02/03/2019] [Indexed: 06/09/2023]
Abstract
Chemical contaminants have been found in the tissues of sea turtles from all over the world; however, very little is known about the effects. Recently, in vitro alternatives to live animal testing have been applied to sea turtles due to their ethical and practical benefits. While primary skin fibroblasts have been established for several species of sea turtle, cells from internal organs are lacking, though they may be more relevant due to the well documented accumulation of contaminants within internal tissues. This study established primary cell cultures from the small intestine, heart, liver, ovary and skin of green turtles (Chelonia mydas). Cells were exposed to ten contaminants typically found in sea turtles to examine potential variations in sensitivity among cells established from different organs. Differences between cells established from different animals were also examined, including a comparison of cells established from a turtle with fibropapillomatosis (FP) and healthy turtles. Loggerhead (Caretta caretta) primary skin cells were also included for species comparisons. Significant differences were found between the organ types, with liver and heart being the least sensitive, and skin being the most sensitive. Overall, variation between the organ types was low. Primary skin fibroblasts may be a suitable and representative cell type for in vitro turtle toxicology research, as it is relatively easy to obtain from healthy live animals. Skin cultures provide a more sensitive indication of effect, and could be used as an early warning of the potential effects of chemical contamination. Some species differences were found but no differences were found between cell cultures from an FP turtle and healthy turtles. When EC50 values were compared to accumulation values from the literature, inorganic contaminants, such as Zn, Cd, Cr, Hg, and Cu were identified as posing a potential risk to sea turtle populations around the world.
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Affiliation(s)
- Kimberly A Finlayson
- Australian Rivers Institute, School of Environment and Science, Griffith University, Gold Coast, Australia.
| | - Frederic D L Leusch
- Australian Rivers Institute, School of Environment and Science, Griffith University, Gold Coast, Australia
| | - Jason P van de Merwe
- Australian Rivers Institute, School of Environment and Science, Griffith University, Gold Coast, Australia
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Liu X, Liu L. Effect of valve lesion on venous valve cycle: A modified immersed finite element modeling. PLoS One 2019; 14:e0213012. [PMID: 30830909 PMCID: PMC6398833 DOI: 10.1371/journal.pone.0213012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 02/13/2019] [Indexed: 01/21/2023] Open
Abstract
The present study aimed to understand the effect of venous valve lesion on the valve cycle. A modified immersed finite element method was used to model the blood–tissue interactions in the pathological vein. The contact process between leaflets or between leaflet and sinus was evaluated using an adhesive contact method. The venous valve modeling was validated by comparing the results of the healthy valve with those of experiments and other simulations. Four valve lesions induced by the abnormal elasticity variation were considered for the unhealthy valve: fibrosis, atrophy, incomplete fibrosis, and incomplete atrophy. The opening orifice area was inversely proportional to the structural stiffness of the valve, while the transvalvular flow velocity was proportional to the structural stiffness of the valve. The stiffening of the fibrotic leaflet led to a decrease in the orifice area and a stronger jet. The leaflet and blood wall shear stress (WSS) in fibrosis was the highest. The softening of the atrophic leaflet resulted in overly soft behavior. The venous incompetence and reflux were observed in atrophy. Also, the atrophic leaflet in incomplete atrophy exhibited weak resistance to the hemodynamic action, and the valve was reluctant to be closed owing to the large rotation of the healthy leaflet. Low blood WSS and maximum leaflet WSS existed in all the cases. A less biologically favorable condition was found especially in the fibrotic leaflet, involving a higher mechanical cost. This study provided an insight into the venous valve lesion, which might help understand the valve mechanism of the diseased vein. These findings will be more useful when the biology is also understood. Thus, more biological studies are needed.
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Affiliation(s)
- Xiang Liu
- School of Science, Wuhan University of Technology, Wuhan, China
- Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics, Wuhan University of Technology, Wuhan, China
| | - Lisheng Liu
- Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics, Wuhan University of Technology, Wuhan, China
- State Key Laboratory of Advanced Technology of Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, China
- * E-mail:
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Aramburu J, Antón R, Rivas A, Ramos JC, Larraona GS, Sangro B, Bilbao JI. A methodology for numerically analysing the hepatic artery haemodynamics during B-TACE: a proof of concept. Comput Methods Biomech Biomed Engin 2019; 22:518-532. [PMID: 30732467 DOI: 10.1080/10255842.2019.1567720] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Balloon-occluded transarterial chemoembolisation (B-TACE) is an intraarterial transcatheter treatment for liver cancer. In B-TACE, an artery-occluding microballoon catheter occludes an artery and promotes collateral circulation for drug delivery to tumours. This paper presents a methodology for analysing the haemodynamics during B-TACE, by combining zero-dimensional and three-dimensional modelling tools. As a proof of concept, we apply the methodology to a patient-specific hepatic artery geometry and analyse two catheter locations. Results show that the blood flow redistribution can be predicted in this proof-of-concept study, suggesting that this approach could potentially be used to optimise catheter location.
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Affiliation(s)
- Jorge Aramburu
- a Universidad de Navarra , TECNUN Escuela de Ingenieros , Donostia-San Sebastián , Spain
| | - Raúl Antón
- a Universidad de Navarra , TECNUN Escuela de Ingenieros , Donostia-San Sebastián , Spain.,b Instituto de Investigación Sanitaria de Navarra (IdiSNA) , Pamplona , Spain
| | - Alejandro Rivas
- a Universidad de Navarra , TECNUN Escuela de Ingenieros , Donostia-San Sebastián , Spain
| | - Juan Carlos Ramos
- a Universidad de Navarra , TECNUN Escuela de Ingenieros , Donostia-San Sebastián , Spain
| | - Gorka S Larraona
- a Universidad de Navarra , TECNUN Escuela de Ingenieros , Donostia-San Sebastián , Spain
| | - Bruno Sangro
- b Instituto de Investigación Sanitaria de Navarra (IdiSNA) , Pamplona , Spain.,c Clínica Universidad de Navarra , Pamplona , Spain.,d Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD) , Pamplona , Spain
| | - José Ignacio Bilbao
- b Instituto de Investigación Sanitaria de Navarra (IdiSNA) , Pamplona , Spain.,c Clínica Universidad de Navarra , Pamplona , Spain
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Finlayson KA, Leusch FDL, van de Merwe JP. Primary green turtle (Chelonia mydas) skin fibroblasts as an in vitro model for assessing genotoxicity and oxidative stress. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2019; 207:13-18. [PMID: 30502692 DOI: 10.1016/j.aquatox.2018.11.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 11/26/2018] [Accepted: 11/26/2018] [Indexed: 06/09/2023]
Abstract
Little is known about the effects of contaminants that accumulate in sea turtles. When in vivo exposure studies have ethical and logistical barriers, as is the case with sea turtles, in vitro tools can provide important information on the effects of contaminants. Several in vitro studies have assessed cytotoxicity of contaminants to sea turtles cells, however to gain a more refined mechanistic understanding of the effects of contaminants, sub-lethal effects also require investigation. Considering the complex mixture of contaminants that sea turtles are potentially exposed to, high throughput testing methods are necessary so that a large number of contaminants (and mixtures) can be rapidly tested. This study examined oxidative stress (reactive oxygen species production) and genotoxicity (micronucleus formation) in primary green turtle skin fibroblasts in response to 16 organic and inorganic contaminants found in coastal environments. Significant induction of oxidative stress was found with Cu, Co, Cr, and Hg. Significant effects on genotoxicity were found with Cu, Co, Cr, Hg, Pb and metolachlor. Effect concentrations from the bioassays were used in a simple risk assessment of turtles worldwide using accumulation values from the literature to identify populations at risk. Cu, Co, Cr and Hg were identified as posing the biggest threat to sea turtles. This study demonstrated the validity of using primary turtle cell cultures in the assessment of risk associated with a large number of contaminants using a high-throughput toxicity testing format.
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Affiliation(s)
- Kimberly A Finlayson
- Australian Rivers Institute, School of Environment and Science, Griffith University, Gold Coast, Australia.
| | - Frederic D L Leusch
- Australian Rivers Institute, School of Environment and Science, Griffith University, Gold Coast, Australia
| | - Jason P van de Merwe
- Australian Rivers Institute, School of Environment and Science, Griffith University, Gold Coast, Australia
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Fossan FE, Sturdy J, Müller LO, Strand A, Bråten AT, Jørgensen A, Wiseth R, Hellevik LR. Uncertainty Quantification and Sensitivity Analysis for Computational FFR Estimation in Stable Coronary Artery Disease. Cardiovasc Eng Technol 2018; 9:597-622. [PMID: 30382522 DOI: 10.1007/s13239-018-00388-w] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 10/12/2018] [Indexed: 12/21/2022]
Abstract
PURPOSE The main objectives of this study are to validate a reduced-order model for the estimation of the fractional flow reserve (FFR) index based on blood flow simulations that incorporate clinical imaging and patient-specific characteristics, and to assess the uncertainty of FFR predictions with respect to input data on a per patient basis. METHODS We consider 13 patients with symptoms of stable coronary artery disease for which 24 invasive FFR measurements are available. We perform an extensive sensitivity analysis on the parameters related to the construction of a reduced-order (hybrid 1D-0D) model for FFR predictions. Next we define an optimal setting by comparing reduced-order model predictions with solutions based on the 3D incompressible Navier-Stokes equations. Finally, we characterize prediction uncertainty with respect to input data and identify the most influential inputs by means of sensitivity analysis. RESULTS Agreement between FFR computed by the reduced-order model and by the full 3D model was satisfactory, with a bias ([Formula: see text]) of [Formula: see text] at the 24 measured locations. Moreover, the uncertainty related to the factor by which peripheral resistance is reduced from baseline to hyperemic conditions proved to be the most influential parameter for FFR predictions, whereas uncertainty in stenosis geometry had greater effect in cases with low FFR. CONCLUSION Model errors related to solving a simplified reduced-order model rather than a full 3D problem were small compared with uncertainty related to input data. Improved measurement of coronary blood flow has the potential to reduce uncertainty in computational FFR predictions significantly.
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Affiliation(s)
- Fredrik E Fossan
- Department of Structural Engineering, Norwegian University of Science and Technology, Trondheim, Norway.
| | - Jacob Sturdy
- Department of Structural Engineering, Norwegian University of Science and Technology, Trondheim, Norway
| | - Lucas O Müller
- Department of Structural Engineering, Norwegian University of Science and Technology, Trondheim, Norway
| | - Andreas Strand
- Department of Structural Engineering, Norwegian University of Science and Technology, Trondheim, Norway
| | - Anders T Bråten
- Clinic of Cardiology, St. Olavs Hospital, Trondheim, Norway
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway
| | - Arve Jørgensen
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway
- Department of Radiology and Nuclear Medicine, St. Olavs Hospital, Trondheim, Norway
| | - Rune Wiseth
- Clinic of Cardiology, St. Olavs Hospital, Trondheim, Norway
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway
| | - Leif R Hellevik
- Department of Structural Engineering, Norwegian University of Science and Technology, Trondheim, Norway
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Joseph J, P M N, Shah MI, Sivaprakasam M. Arterial compliance probe for cuffless evaluation of carotid pulse pressure. PLoS One 2018; 13:e0202480. [PMID: 30114216 PMCID: PMC6095577 DOI: 10.1371/journal.pone.0202480] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 08/04/2018] [Indexed: 01/06/2023] Open
Abstract
OBJECTIVE Assessment of local arterial properties has become increasingly important in cardiovascular research as well as in clinical domains. Vascular wall stiffness indices are related to local pulse pressure (ΔP) level, mechanical and geometrical characteristics of the arterial vessel. Non-invasive evaluation of local ΔP from the central arteries (aorta and carotid) is not straightforward in a non-specialist clinical setting. In this work, we present a method and system for real-time and beat-by-beat evaluation of local ΔP from superficial arteries-a non-invasive, cuffless and calibration-free technique. METHODS The proposed technique uses a bi-modal arterial compliance probe which consisted of two identical magnetic plethysmograph (MPG) sensors located at 23 mm distance apart and a single-element ultrasound transducer. Simultaneously measured local pulse wave velocity (PWV) and arterial dimensions were used in a mathematical model for calibration-free evaluation of local ΔP. The proposed approach was initially verified using an arterial flow phantom, with invasive pressure catheter as the reference device. The developed porotype device was validated on 22 normotensive human subjects (age = 24.5 ± 4 years). Two independent measurements of local ΔP from the carotid artery were made during physically relaxed and post-exercise condition. RESULTS Phantom-based verification study yielded a correlation coefficient (r) of 0.93 (p < 0.001) for estimated ΔP versus reference brachial ΔP, with a non-significant bias and standard deviation of error equal to 1.11 mmHg and ±1.97 mmHg respectively. The ability of the developed system to acquire high-fidelity waveforms (dual MPG signals and ultrasound echoes from proximal and distal arterial walls) from the carotid artery was demonstrated by the in-vivo validation study. The group average beat-to-beat variation in measured carotid local PWV, arterial diameter parameters-distension and end-diastolic diameter, and local ΔP were 4.2%, 2.6%, 3.3%, and 10.2% respectively in physically relaxed condition. Consistent with the physiological phenomenon, local ΔP measured from the carotid artery of young populations was, on an average, 22 mmHg lower than the reference ΔP obtained from the brachial artery. Like the reference brachial blood pressure (BP) monitor, the developed prototype device reliably captured variations in carotid local ΔP induced by an external intervention. CONCLUSION This technique could provide a direct measurement of local PWV, arterial dimensions, and a calibration-free estimate of beat-by-beat local ΔP. It can be potentially extended for calibration-free cuffless BP measurement and non-invasive characterization of central arteries with locally estimated biomechanical properties.
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Affiliation(s)
- Jayaraj Joseph
- Healthcare Technology Innovation Centre, Indian Institute of Technology Madras, Chennai, Tamil Nadu, India
| | - Nabeel P M
- Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai, Tamil Nadu, India
| | - Malay Ilesh Shah
- Healthcare Technology Innovation Centre, Indian Institute of Technology Madras, Chennai, Tamil Nadu, India
| | - Mohanasankar Sivaprakasam
- Healthcare Technology Innovation Centre, Indian Institute of Technology Madras, Chennai, Tamil Nadu, India
- Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai, Tamil Nadu, India
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Yao HD, Svensson MY, Nilsson H. Deformation of dorsal root ganglion due to pressure transients of venous blood and cerebrospinal fluid in the cervical vertebral canal. J Biomech 2018; 76:16-26. [PMID: 29801662 DOI: 10.1016/j.jbiomech.2018.05.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 04/26/2018] [Accepted: 05/07/2018] [Indexed: 11/17/2022]
Abstract
The dorsal root ganglion (DRG) that is embedded in the foramen of the cervical vertebra can be injured during a whiplash motion. A potential cause is that whilst the neck bends in the whiplash motion, the changes of spinal canal volume induce impulsive pressure transients in the venous blood outside the dura mater (DM) and in the cerebrospinal fluid (CSF) inside the DM. The fluids can dynamically interact with the DRG and DM, which are deformable. In this work, the interaction is investigated numerically using a strong-coupling partitioned method that synchronize the computations of the fluid and structure. It is found that the interaction includes two basic processes, i.e., the pulling and pressing processes. In the pulling process, the DRG is stretched towards the spinal canal, and the venous blood is driven into the canal via the foramen. This process results from negative pressure in the fluids. In contrast, the pressing process is caused by positive pressure that leads to compression of the DRG and the outflow of the venous blood from the canal. The largest pressure gradient is observed at the foramen, where the DRG is located at. The DRG is subject to prominent von Mises stress near its end, which is fixed without motions. The negative internal pressure is more efficient to deform the DRG than the positive internal pressure. This indicates that the most hazardous condition for the DRG is the pulling process.
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Affiliation(s)
- Hua-Dong Yao
- Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
| | - Mats Y Svensson
- Chalmers University of Technology, SE-412 96 Gothenburg, Sweden; SAFER Vehicle and Traffic Safety Centre, Chalmers University of Technology, Sweden
| | - Håkan Nilsson
- Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
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Aramburu J, Antón R, Rivas A, Ramos JC, Larraona GS, Sangro B, Bilbao JI. Numerical zero-dimensional hepatic artery hemodynamics model for balloon-occluded transarterial chemoembolization. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e2983. [PMID: 29575739 DOI: 10.1002/cnm.2983] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 02/28/2018] [Accepted: 03/04/2018] [Indexed: 06/08/2023]
Abstract
Balloon-occluded transarterial chemoembolization (B-TACE) is a valuable treatment option for patients with inoperable malignant tumors in the liver. Balloon-occluded transarterial chemoembolization consists of the transcatheter infusion of an anticancer drug mixture and embolic agents. Contrary to conventional TACE, B-TACE is performed via an artery-occluding microballoon catheter, which makes the blood flow to redistribute due to the intra- and extrahepatic arterial collateral circulation. Several recent studies have stressed the importance of the redistribution of blood flow in enhancing the treatment outcome. In the present study, the geometries of a representative hepatic artery and the communicating arcades (CAs) are modeled. An in silico zero-dimensional hemodynamic model is created by characterizing the geometry and the boundary conditions and then is validated in vitro. The role of CAs is assessed by combining 2 cancer scenarios and 2 catheter locations. The importance of the diameter of the CAs is also studied. Results show that occluding a main artery leads to collateral circulation and CAs start to play a role in blood-flow redistribution. In summary, numerical zero-dimensional simulations permit a fast and reliable approach for exploring the blood-flow redistribution caused by the occlusion of a main artery, and this approach could be used during B-TACE planning.
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Affiliation(s)
- Jorge Aramburu
- TECNUN Escuela de Ingenieros, Universidad de Navarra, P° Manuel Lardizabal 13, 20018, Donostia-San Sebastián, Spain
| | - Raúl Antón
- TECNUN Escuela de Ingenieros, Universidad de Navarra, P° Manuel Lardizabal 13, 20018, Donostia-San Sebastián, Spain
- Instituto de Investigación Sanitaria de Navarra (IdiSNA), Av. Pío XII 36, 31008, Pamplona, Spain
| | - Alejandro Rivas
- TECNUN Escuela de Ingenieros, Universidad de Navarra, P° Manuel Lardizabal 13, 20018, Donostia-San Sebastián, Spain
| | - Juan Carlos Ramos
- TECNUN Escuela de Ingenieros, Universidad de Navarra, P° Manuel Lardizabal 13, 20018, Donostia-San Sebastián, Spain
| | - Gorka S Larraona
- TECNUN Escuela de Ingenieros, Universidad de Navarra, P° Manuel Lardizabal 13, 20018, Donostia-San Sebastián, Spain
| | - Bruno Sangro
- Instituto de Investigación Sanitaria de Navarra (IdiSNA), Av. Pío XII 36, 31008, Pamplona, Spain
- Clínica Universidad de Navarra, Av. Pío XII 36, 31008, Pamplona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Av. Pío XII 36, 31008, Pamplona, Spain
| | - José Ignacio Bilbao
- Instituto de Investigación Sanitaria de Navarra (IdiSNA), Av. Pío XII 36, 31008, Pamplona, Spain
- Clínica Universidad de Navarra, Av. Pío XII 36, 31008, Pamplona, Spain
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Xu F, Morganti S, Zakerzadeh R, Kamensky D, Auricchio F, Reali A, Hughes TJ, Sacks MS, Hsu MC. A framework for designing patient-specific bioprosthetic heart valves using immersogeometric fluid-structure interaction analysis. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e2938. [PMID: 29119728 PMCID: PMC5893448 DOI: 10.1002/cnm.2938] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 09/08/2017] [Accepted: 10/22/2017] [Indexed: 05/07/2023]
Abstract
Numerous studies have suggested that medical image derived computational mechanics models could be developed to reduce mortality and morbidity due to cardiovascular diseases by allowing for patient-specific surgical planning and customized medical device design. In this work, we present a novel framework for designing prosthetic heart valves using a parametric design platform and immersogeometric fluid-structure interaction (FSI) analysis. We parameterize the leaflet geometry using several key design parameters. This allows for generating various perturbations of the leaflet design for the patient-specific aortic root reconstructed from the medical image data. Each design is analyzed using our hybrid arbitrary Lagrangian-Eulerian/immersogeometric FSI methodology, which allows us to efficiently simulate the coupling of the deforming aortic root, the parametrically designed prosthetic valves, and the surrounding blood flow under physiological conditions. A parametric study is performed to investigate the influence of the geometry on heart valve performance, indicated by the effective orifice area and the coaptation area. Finally, the FSI simulation result of a design that balances effective orifice area and coaptation area reasonably well is compared with patient-specific phase contrast magnetic resonance imaging data to demonstrate the qualitative similarity of the flow patterns in the ascending aorta.
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Affiliation(s)
- Fei Xu
- Department of Mechanical Engineering, Iowa State University, 2025 Black Engineering, Ames, IA 50011, USA
| | - Simone Morganti
- Department of Electrical, Computer, and Biomedical Engineering, University of Pavia, via Ferrata 3, 27100, Pavia Italy
| | - Rana Zakerzadeh
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, The University of Texas at Austin, 201 East 24th St, Stop C0200, Austin, TX 78712, USA
| | - David Kamensky
- Department of Structural Engineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0085 La Jolla, CA 92093, USA
| | - Ferdinando Auricchio
- Department of Civil Engineering and Architecture, University of Pavia, via Ferrata 3, 27100, Pavia, Italy
| | - Alessandro Reali
- Department of Civil Engineering and Architecture, University of Pavia, via Ferrata 3, 27100, Pavia, Italy
| | - Thomas J.R. Hughes
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, The University of Texas at Austin, 201 East 24th St, Stop C0200, Austin, TX 78712, USA
| | - Michael S. Sacks
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, The University of Texas at Austin, 201 East 24th St, Stop C0200, Austin, TX 78712, USA
| | - Ming-Chen Hsu
- Department of Mechanical Engineering, Iowa State University, 2025 Black Engineering, Ames, IA 50011, USA
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Dörp E, Schneditz D, Moser M. The Measurement of Blood Density to Investigate Protein Deposition at the blood/hollow Fiber Membrane Interface during Ultrafiltration. Int J Artif Organs 2018. [DOI: 10.1177/039139889101400708] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- E. Dörp
- Faculty of Medicine, University of Rostock, Rostock - Germany
| | - D. Schneditz
- Department of Physiology, Karl-Franzens University, Graz - Austria
| | - M. Moser
- Department of Physiology, Karl-Franzens University, Graz - Austria
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50
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Hazama H, Yoshimori M, Honda N, Awazu K. Evaluation of Endovenous Laser Ablation for Varicose Veins Using a Computer Simulation Model (Secondary publication). Laser Ther 2017; 26:282-287. [PMID: 29434428 DOI: 10.5978/islsm.17-re-03] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 11/11/2017] [Indexed: 11/06/2022]
Abstract
Background and aims Endovenous laser ablation (EVLA) has been well-reported as a minimally invasive method to deal with varices of the lower extremities. The lasers used fall into two categories: pigment, i.e., hemoglobin-specific lasers in the visible and near-infrared (near-IR) wavebands and longer wavelength mid-infrared lasers where the chromophore is water. The fiber used to deliver the laser energy is also important, and not enough attention has been paid to this element of EVLA. The present study was therefore designed to compare EVLA delivered through two specific fiber types coupled with a near-IR laser wavelength where water was the major chromophore. Materials and methods A laser diode system at the wavelength of 1470 nm was used as the laser energy source near a peak in the water absorption spectrum. Laser energy was delivered with two specific types of optical fiber, a Radial™ fiber and a Radial 2ring™ fiber (CeramOptec, Germany), and EVLA was evaluated using a computer simulation model taking light transport into account based on the Monte Carlo method and temperature distribution with the heat conduction equation. Results and conclusions It was confirmed from both the simulation model and a previously published ex vivo experiment that carbonization and sticking during EVLA caused by excess temperature rise can be minimized by using the Radial 2ring fiber compared with the Radial fiber, coupled with the 1470 nm wavelength. In the future, lasers with different wavelengths or optical fibers with differing irradiation modes may appear as candidate systems for EVLA. It is important to evaluate safety and efficacy carefully using the methods in the present study before moving to in vivo indications in human subjects.
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Affiliation(s)
| | | | | | - Kunio Awazu
- Graduate School of Engineering, Osaka University.,Graduate School of Frontier Biosciences, Osaka University.,Global Center for Medical Engineering and Informatics
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