Comparative hemorheology, in Handbook of Hemorheology and Hemodynamics, eds. O. K. Baskurt, M. R. Hardeman, M. W. Rampling, and. Article · January. Handbook of Hemorheology and Hemodynamics – Ebook download as PDF File .pdf), Text File .txt) or read book online. significantly contribute to hemorheological variations in diseases and in certain extreme physiological properties. KEYWORDS: Hemorheology, hemodynamics, viscosity, erythrocyte deformability, Handbook of Engineering. New York.
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The results clearly indicated that the apparent viscosity of blood determined using the flow rate through the hind limb was lower than the value obtained using the glass viscometer Figure 1. However, the specific mechanisms involved in RBC aggregation have not yet been elucidated, and thus it is not yet possible to fully understand the relations between pathology and altered RBC aggregation.
While the resistance to flow spans nearly five decades as blood courses its way from arteriole to venule, the large scatter in the experimental data may reflect significant departures from the flow of a Newtonian fluid through a smooth walled tube of circular cross-section.
Clinical Aspects of Hemorheology. Given the importance of these adhesive processes, it is not surprising that they have been widely studied both in vivo using intravital microscopy and in vitro using flow-based models.
In the bridging model, red cell aggregation is proposed to occur when the bridging forces due to the adsorption of macromolecules onto adjacent cell surfaces exceed disaggregating forces due to electrostatic repulsion, membrane strain and mechanical shearing [15, ].
Handbook of Hemorheology and Hemodynamics – Google Books
On the other hand, sudden changes of rheologic properties may develop in the perinatal period with marked effects on circulation such as polycythemia resulting from placental transfusion . Different species also use different mechanisms to maintain blood flow, and in some cases these differences might indicate which variables limit the demand for oxygen delivery in a species or under certain circumstances.
Therefore changes in parameters during disease, after interventions, or during environmental or associated changes need to be related to their species-specific reference values; describing an animal’s clinical or physiological condition using comparisons to values from other species is most likely not a valid approach. Series Biomedical and Health Research.
In this chapter no comprehensive treatment of all described methods and techniques has been attempted. Handbook of Hemorheology and Hemodynamics Oguz K. Vascular endothelium is a monocellular layer positioned between the muscular media, or the adventitia in capillaries, and the circulating blood . Hemorheology and hemodynamics are closely related, the former dealing with all aspects of the flow and interactions of the individual blood cells mostly studied in vitro, the latter with the in vivo relationships among vessel architecture, driving pressure, flow rate and shear stress.
Meiselman hematocrit hemodilution hemodynamics hemoglobin hemolysis Hemorheol hemorheological parameters human hyperviscosity impaired increased interactions ischemia ischemic layer leukocytes levels Linderkamp low shear measured mechanical properties Microcirc microcirculation microcirculatory microvascular microvessels mPa.
Since many aspects of hemorheology and hemodynamics are affected by disease or clinical states, these effects are discussed as are hyperviscosity syndromes, therapy for disturbed blood rheology, and methods in hemorheology and hemodynamics.
This provides a basis for consideration of a range of more complex fluid dynamical phenomena occurring in the circulatory system. This chapter gives an overview of the composition of normal adult human blood and some indication of the ways in which it can be altered in diseased states.
Finally, some general practical hemorheological laboratory techniques are described. The contribution of these factors to blood rheology has been detailed in previous chapters Chapters II. Also, in the s and s a number of books were published that focused on clinical aspects of blood rheology [2—5]. Abstract Inages before there was any concept of blood viscosity, it was appreciated by Anthony van Leeuwenhoek Delft, the Netherlands that red blood cells RBC have to deform in order to negotiate capillary passages .
Of a number of disorders affecting the mechanical and adhesive properties of human RBC, homozygous sickle cell disease and malaria are arguably the most important and certainly, in the case of malaria, the most studied. Furthermore, the blood must circulate above a limiting rate if it is to do its work effectively enough to keep the organism healthy. This rate of circulation is determined by the driving pressure generated by the heart, by the geometrical resistance offered by the vasculature and by the flow properties of the blood.
This borderline oxygen supply makes the fetus extremely vulnerable to hypoxicischemic events. These classifications, based on the mechanisms of hemorheological alterations, need to be revised in light of developments in the past twenty years. Activation at the vessel wall is a necessary part of their physiological migratory response, but if it occurs inappropriately, circulating cells have the potential to cause pathogenic microvascular occlusion .
The elastic energy is measurable when flow changes with time.
Whittaker and Winton compared the apparent viscosity of blood under a constant pressure difference as determined by simultaneously measuring flow through a dog hind limb preparation and a glass viscometer arranged in parallel. For red blood cells RBC to survive in the harsh hemodynamic environment of the circulation in vivo, they must remain non-adhesive and maintain a set of unique stability.
Since many aspects of hemorheology and hemodynamics are affected by disease or clinical states, these effects are discussed as are hyperviscosity syndromes, therapy for disturbed blood rheology, and methods in hemorheology and hemodynamics. This is done by use of the physical principle known as the conservation of momentum, and results in equations which relate the forces to velocity gradients.
Leblond in an early, textbook of hemorheology, hyperviscosity syndromes were discussed from a pathophysiological point of view : In addition, some information on developmental hemorheology during infancy and childhood will also be presented.
Abstract The factors that determine the rheological behavior of blood, a two-phase fluid, include the relative volume of each phase as reflected by the hematocrit value, plasma composition and the properties of cellular elements.
Ebook: Handbook of Hemorheology and Hemodynamics
The editors of the handbook have each been active in the fields of bio- and hemorheology for many years, and have published extensively. The linkage between the in vitro and in vivo research described in the book will be of interest to both basic science and clinical investigators.
A related subject, the damage sustained by red cells due to flow-induced mechanical trauma, is also presented. Using finely drawn pipettes inserted into microvessels of frog mesentery, and calculating the velocity of bolus infusions of dyes through successive microvascular divisions, Landis attempted to calculate hemoxynamics resistance to flow within the capillary network and concluded that Poiseulle’s law cannot be applied to the flow of blood through the capillary network except in a very limited sense.
In turn, these stimuli trigger a response that is mediated by the release of a number of autocrine and paracrine substances. Mechanical Trauma to Blood. Abstract Vascular endothelium is a monocellular layer positioned between the muscular media, or the adventitia in capillaries, and the circulating blood . It also affects the efficiency with which cells are brought into contact with the wall because margination in the flow depends on the concentration of the red cells and their flow-dependent tendency to aggregate .
Finally, there is a brief review of the variations that occur in other mammals, emphasizing the similarities hemorheologh the great differences that exist compared with the human adult.