Biorheology最新文献

{"title":"Characterisation and optimisation of foams for varicose vein sclerotherapy.","authors":"T G Roberts,&nbsp;S J Cox,&nbsp;A L Lewis,&nbsp;S A Jones","doi":"10.3233/BIR-201004","DOIUrl":"https://doi.org/10.3233/BIR-201004","url":null,"abstract":"<p><strong>Background: </strong>Foam sclerotherapy is the process of using an aqueous foam to deliver surfactant to a varicose vein to damage vein wall endothelial cells, causing the vein to spasm, collapse and ultimately be re-absorbed into the body. Aqueous foams are complex fluids that can exhibit a significant yield stress and high effective viscosity which depend on their composition, particularly the bubble size and liquid fraction.</p><p><strong>Objective: </strong>To characterise the properties of foams used for varicose vein sclerotherapy and determine their effectiveness in the displacement of blood during sclerotherapy.</p><p><strong>Methods: </strong>Foams are modelled as yield stress fluids and their flow profiles in a model vein are predicted. Values of the yield stress are determined from experimental data for three different foams using the Sauter mean of the bubble size distribution. Along with the measured liquid fraction of the foams, this information is collected into a Bingham number which entirely characterises the process of sclerotherapy.</p><p><strong>Results: </strong>Polydispersity in bubble size has a strong effect on the yield stress of a foam and the Sauter mean of the size distribution better captures the effects of a few large bubbles. Reducing the polydispersity increases the yield stress, and a higher yield stress results in a larger plug region moving along the vein, which is more effective in displacing blood. The width of the plug region is proportional to the Bingham number, which also has a quadratic dependence on the liquid fraction of the foam. Assuming typical values for the rate of injection of a foam, we predict that for a vein of diameter 5 mm, the most effective foams have low liquid fraction, a narrow size distribution, and a Bingham number B ≈ 4.5.</p><p><strong>Conclusions: </strong>The Sauter mean radius provides the most appropriate measure of the bubble size for sclerotherapy and the Bingham number then provides a simple measure of the efficacy of foam sclerotherapy in a vein of a given size, and explains the ability of different foams to remove varicose veins. Foams containing small bubbles, with a narrow size distribution, and a low liquid fraction are beneficial for sclerotherapy.</p>","PeriodicalId":9167,"journal":{"name":"Biorheology","volume":"57 2-4","pages":"77-85"},"PeriodicalIF":1.1,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/BIR-201004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38751597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Porcine bile viscosity is proportional to density.","authors":"Nguyen Ngoc Minh,&nbsp;Hiromichi Obara","doi":"10.3233/BIR-190238","DOIUrl":"https://doi.org/10.3233/BIR-190238","url":null,"abstract":"<p><strong>Background: </strong>The gallbladder filling and emptying cycle controls bile flow into the duodenum. Disruption of this emptying and refilling cycle leads to bile stasis and subsequent gallstone formation. The bile flow rate is inversely proportional to its viscosity. Moreover, bile is a complex material with varying density in different people because of its diverse components. These density changes alter the viscosity. Prediction of shear viscosity from density measurements may thus contribute to medical assessment and treatment of the patient.</p><p><strong>Objective: </strong>To investigate the relationship between the shear viscosity and density of bile.</p><p><strong>Methods: </strong>Natural and filtered bile samples were prepared for density, viscosity and pressure drop measurements. The density and shear viscosity were measured by a density meter and viscometer, respectively, and a relationship was established between them. Measurements of the pressure drop in a glass tube were used to estimate the apparent viscosity and compared with shear viscosity obtained with the viscometer.</p><p><strong>Results: </strong>The natural bile with higher density showed a greater shear viscosity than the filtered bile, especially at low shear rates. Bile viscosity was proportional to density. In addition, the pressure drop of the natural samples was greater than that of the filtered sample. The viscosity measured by the viscometer deviated from the results obtained using Poiseuille's law and the tube pressure drop measurements. The density difference between the natural and filtered bile samples was smaller than 1%. However, the viscosities of the natural and filtered bile samples varied by up to >30%.</p><p><strong>Conclusions: </strong>Porcine bile viscosity is proportional to density. Based on the bile density, one can easily evaluate the shear viscosity using a linear relationship. The density considerably influences the bile viscosity, with small density increases greatly increasing the shear viscosity.</p>","PeriodicalId":9167,"journal":{"name":"Biorheology","volume":"57 1","pages":"27-36"},"PeriodicalIF":1.1,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/BIR-190238","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37871153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preface.","authors":"H. Lipowsky","doi":"10.3233/bir-190233","DOIUrl":"https://doi.org/10.3233/bir-190233","url":null,"abstract":"","PeriodicalId":9167,"journal":{"name":"Biorheology","volume":"56 2-3 1","pages":"73-75"},"PeriodicalIF":1.1,"publicationDate":"2019-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/bir-190233","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42826730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Relative shedding of glycosaminoglycans from the endothelial glycocalyx during inflammation and their contribution to stiffness of the glycocalyx.","authors":"H. Lipowsky","doi":"10.3233/BIR-190225","DOIUrl":"https://doi.org/10.3233/BIR-190225","url":null,"abstract":"BACKGROUND\u0000The endothelial (EC) surface layer (glycocalyx) has been shown to act as a barrier to transvascular exchange of solutes, and adhesion of leukocytes (WBCs) during the inflammatory process. It is a labile structure whose components are readily shed by the action of proteases and endoglycosidases. Details of shedding of specific constituents of the glycocalyx remain to be determined.\u0000\u0000\u0000OBJECTIVES\u0000To review the contributions of the primary glycosaminoglycans that comprise the glycocalyx, heparan sulfate (HS), chondroitin sulfate (CS) and hyaluronan (HA), as barrier to WBC-EC adhesion, and elucidate the rates of shedding of each component in response to an inflammatory stimulus. Assess the potential role that stiffness of the glycocalyx plays in resisting infiltration by WBCs during the adhesion process.\u0000\u0000\u0000METHODS\u0000Quantitate shedding of the glycocalyx in post-capillary venules of rat mesentery in response to superfusion of the tissue with 10-6 M fMLP. The presence and loss of HS, CS and HA was assessed by labeling all components with fluorescently labelled lectin (BS-1) or HS antibodies, and HA with fluorescently labelled hyaluronan binding protein (HBP).\u0000\u0000\u0000RESULTS\u0000Following a 30 min exposure of the mesentery to fMLP about 50% of HBP was lost in contrast to a previously shown loss of 20% of lectin labelled GAGs, and 25% loss of Mab labelled HS. The time constant for HBP shedding (5.8 min) was one-third that for BS-1 labelled GAGs (14.3 min). An attempt was made to assess stiffness of the glycocalyx by observing the motion of adhered lectin coated fluorescently labelled microspheres (FLM) under oscillatory flow conditions. Estimates of the elastic modulus of the glycocalyx revealed a value of 26 mPa, which was orders of magnitude below published data obtained by atomic force microscopy.\u0000\u0000\u0000CONCLUSIONS\u0000The relatively rapid shedding of HA compared to HS was consistent with the hypothesis that HA may form the dominant barrier to WBC-EC adhesion. Prior observations that HA lies closer to and parallel to the endothelial membrane, compared to HS suggests that the compact layer of HA near the EC membrane surrounds WBC adhesion receptors that are much shorter in length than the total thickness of the glycocalyx. The relatively low elastic modulus of the glycocalyx under shear is consistent with the hypothesis that the FLMs adhered to strands of HS normal to the EC surface that extended above the relatively more compact and stiffer HA layer below. Gradients of stiffness within the glycocalyx may not be detected by compressive indentation tests published to date.","PeriodicalId":9167,"journal":{"name":"Biorheology","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2019-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/BIR-190225","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47139577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shear-thickening fluids in biologically relevant agents.","authors":"Peter Kilbride,&nbsp;Marina Vazquez Rull,&nbsp;Adam Townsend,&nbsp;Helen Wilson,&nbsp;John Morris","doi":"10.3233/BIR-180196","DOIUrl":"https://doi.org/10.3233/BIR-180196","url":null,"abstract":"<p><strong>Background: </strong>The rheology of shear thickening fluids is well characterized for many physical applications, however the literature surrounding biologically or cryobiologically compatible shear thickening fluids is less well understood.</p><p><strong>Objective: </strong>This study examined fluids consisting of corn-derived hydroxyethyl starch with a variety of sugars and cryoprotectants to characterize their shear-rate viscosity relationship. The objective was to establish if cryobiologically relevant materials could be used to afford biologics protection through shear-thickening.</p><p><strong>Results: </strong>Fluids consisting of 50% hydroxyethyl starch by weight exhibited shear thickening with a variety of cryoprotectants. Lowering the temperature of the fluid both reduced critical shear rates and enhanced thickening magnitude. Starch derived from corn, wheat, and rice all exhibited non-Newtonian shear-dependent viscosity behaviour at 50% by weight in water. Between the starch sources however, the shear-rate viscosity relationship varied widely, with wheat-derived starch shear thinning, and the remaining starches forming shear thickening fluids. Different starch sources had different baseline viscosities, critical shear rates, and rates of viscosity increase.</p><p><strong>Conclusions: </strong>This study established that shear thickening is compatible with cryobiologically relevant agents, particularly so at lower temperatures. This forms the basis for harnessing these phenomena in biological processes such as cryopreservation.</p>","PeriodicalId":9167,"journal":{"name":"Biorheology","volume":"56 1","pages":"39-50"},"PeriodicalIF":1.1,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/BIR-180196","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37006302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microvascular hemodynamics: System properties1.","authors":"Axel R Pries","doi":"10.3233/BIR-190207","DOIUrl":"10.3233/BIR-190207","url":null,"abstract":"<p><p>The hemodynamics of the microcirculation reflect system properties of the involved components. The blood itself is a complex suspension of water, small and large molecules and different cell types. Under most conditions, its rheologic properties are dominated by the different behaviour of fluid and cellular compartments. When perfused through small-bore tubes or vessels, the suspension exhibits specific emergent properties. The Fahraeus-effect and the Fahreaeus-Lindqvist-effect result from the interaction of cellular particles with each other and with the vessel wall. Additional phenomena occur in vascular networks due to the uneven distribution of blood cells and blood plasma at divergent microvascular bifurcations. In order to understand microvascular hemodynamics in vivo but also in artificial microfluidic geometries it is thus necessary to recognize the pertinent system properties on the level of the blood, the microvessels and the microvascular networks or perfused structures.</p>","PeriodicalId":9167,"journal":{"name":"Biorheology","volume":"56 1","pages":"1-13"},"PeriodicalIF":1.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37006303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Endothelial surface glycocalyx (ESG) components and ultra-structure revealed by stochastic optical reconstruction microscopy (STORM).","authors":"Jie Fan,&nbsp;Yi Sun,&nbsp;Yifan Xia,&nbsp;John M Tarbell,&nbsp;Bingmei M Fu","doi":"10.3233/BIR-180204","DOIUrl":"https://doi.org/10.3233/BIR-180204","url":null,"abstract":"<p><strong>Background: </strong>In order to play different roles in vascular functions as a mechanosensor to blood flows and as a barrier to transvascular exchange, the endothelial surface glycocalyx (ESG) should have an organized structure. Due to the limitations of optical and electron microscopy, the ultra-structure of ESG has not been revealed until the recent development of super-resolution optical microscopy, STORM.</p><p><strong>Objectives: </strong>To investigate the ESG components and their organization on bEnd3 (mouse brain microvascular endothelial cells) monolayer.</p><p><strong>Methods: </strong>ESG was immunolabeled with anti-heparan sulfate (HS), followed by an ATTO488 conjugated goat anti-mouse IgG, and with biotinylated hyaluronic acid (HA) binding protein, followed by an AF647 conjugated anti-biotin. The ESG was then imaged by the STORM.</p><p><strong>Results: </strong>HA is a long molecule weaving into a network which covers the endothelial luminal surface. In contrast, HS is a shorter molecule, perpendicular to the cell surface. HA and HS are partially overlapped with each other at the endothelial luminal surface. We also quantified the length, diameter, orientation, and density of HS at the top, middle and bottom regions of the endothelial surface.</p><p><strong>Conclusions: </strong>Our results suggest that HS plays a major role in mechanosensing and HA plays a major role in the molecular sieve.</p>","PeriodicalId":9167,"journal":{"name":"Biorheology","volume":" ","pages":"77-88"},"PeriodicalIF":1.1,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/BIR-180204","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37366759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanobiology of the abluminal glycocalyx.","authors":"P. Butler, A. Bhatnagar","doi":"10.3233/bir-190212","DOIUrl":"https://doi.org/10.3233/bir-190212","url":null,"abstract":"BACKGROUND Endothelial cells (ECs) sense the forces from blood flow through the glycocalyx, a carbohydrate rich luminal surface layer decorating most cells, and through forces transmitted through focal adhesions (FAs) on the abluminal side of the cell. OBJECTIVES This perspective paper explores a complementary hypothesis, that glycocalyx molecules on the abluminal side of the EC between the basement membrane and the EC membrane, occupying the space outside of FAs, work in concert with FAs to sense blood flow-induced shear stress applied to the luminal surface. RESULTS First, we summarize recent studies suggesting that the glycocalyx repels the plasma membrane away from the basement membrane, while integrin molecules attach to extracellular matrix (ECM) ligands. This coordinated attraction and repulsion results in the focal nature of integrin-mediated adhesion making the abluminal glycocalyx a participant in mechanotransduction. Further, the glycocalyx mechanically links the plasma membrane to the basement membrane providing a mechanism of force transduction when the cell deforms in the peri-FA space. To determine if the membrane might deform against a restoring force of an elastic abluminal glycocalyx in the peri-FA space we present some analysis from a multicomponent elastic finite element model of a sheared and focally adhered endothelial cell whose abluminal topography was assessed using quantitative total internal reflection fluorescence microscopy with an assumption that glycocalyx fills the space between the membrane and extracellular matrix. CONCLUSIONS While requiring experimental verification, this analysis supports the hypothesis that shear on the luminal surface can be transmitted to the abluminal surface and deform the cell in the vicinity of the focal adhesions, with the magnitude of deformation depending on the abluminal glycocalyx modulus.","PeriodicalId":9167,"journal":{"name":"Biorheology","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/bir-190212","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69793266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rheological properties and efficacy of the formulation of hyaluronic acid with tamarind seed polysaccharide for arthritis.","authors":"Won Ho Yoon,&nbsp;Keyong Ho Lee","doi":"10.3233/BIR-190208","DOIUrl":"https://doi.org/10.3233/BIR-190208","url":null,"abstract":"<p><strong>Background: </strong>Tamarind seed polysaccharide (TSP) is used as a texturizing agent and a thickener in food and pharmaceutical products. There are no publications describing the addition of TSP to intra-articular injection formulations for arthritis.</p><p><strong>Objective: </strong>The purpose of this study was to investigate the rheology and efficacy of the formulation of TSP with hyaluronic acid (HA) as a new material for injection for arthritis.</p><p><strong>Methods: </strong>We investigated the viscoelastic properties of formulations of HA and TSP as potential lubricants for arthritis, and tested the improvement of right/left paw weight distribution in monosodium iodoacetate-induced arthritis in the rat.</p><p><strong>Results: </strong>HA formulations with 3% and 4% TSP showed improved rheological characteristics and were protected against changes induced by heat sterilization. Addition of TSP also reduced pain in the arthritis model, as evidenced by normalization of the distribution of paw weight.</p><p><strong>Conclusions: </strong>TSP is a potential material as a substitute for HA or in combination with HA for intra-articular injection for arthritis.</p>","PeriodicalId":9167,"journal":{"name":"Biorheology","volume":"56 1","pages":"31-38"},"PeriodicalIF":1.1,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/BIR-190208","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37088540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The endothelial glycocalyx: Barrier functions versus red cell hemodynamics: A model of steady state ultrafiltration through a bi-layer formed by a porous outer layer and more selective membrane-associated inner layer.","authors":"FitzRoy E Curry,&nbsp;C Charles Michel","doi":"10.3233/BIR-180198","DOIUrl":"https://doi.org/10.3233/BIR-180198","url":null,"abstract":"<p><strong>Background: </strong>Ultrastructural investigations of the endothelial glycocalyx reveal a layer adjacent to the cell surface with a structure consistent with the primary  ultrafilter of vascular walls. Theory predicts this layer can be no greater than 200-300 nm thick, a result  to be reconciled with observations that red cells and large macromolecules are excluded  from a region 1 micrometer or more from the cell membrane.</p><p><strong>Objective: </strong>To determine whether this apparent inconsistency might be accounted for by a model of steady state water and protein transport through a glycocalyx bi-layer formed by a porous outer layer in series with a more selective inner layer.</p><p><strong>Methods: </strong>Expressions for coupled water and albumin fluxes through the two layers were used to describe steady state ultra-filtration though the bi-layer model.</p><p><strong>Results: </strong>Albumin accumulates at the interface between the porous layer and the selective inner layer. The osmotic pressure of accumulated albumin significantly modifies the observed permeability properties of the microvessel wall by an effective unstirred layer effect.</p><p><strong>Conclusions: </strong>The model places significant constraints on the outer layer permeability properties . The only outer layer properties that are consistent with measured steady state filtration rates and models of red cell flux through microvessels are an albumin permeability coefficient and hydraulic conductivity more than an order of magnitude larger than the those of the inner layer.</p>","PeriodicalId":9167,"journal":{"name":"Biorheology","volume":" ","pages":"113-130"},"PeriodicalIF":1.1,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/BIR-180198","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"36871328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}