Clinical Aspects of Blood Viscosity and Cell Deformability


Book Description

After many years of relative neglect, the importance of study of factors governing blood flow has at last achieved recognition; in this volume are documented many of the techniques, and the basic scientific and clinical observations, which have helped to open up understanding of this highly important aspect of human physiology and pathology in recent years. The text is logically divided into five sections beginning with blood cell deformability, then moving on to theoretical consideration of blood rheology, followed by accounts of the interrelationships between rheology, blood flow and vascular occlusion. The final two sections deal with blood rheology in clinical practice and therapeutic aspects of the study of blood flow. As regards blood cell deformability (Section A), the basic problem is set out by Kiesewetter and colleagues in the first paragraph of chapter 1 (p. 3), in which they point out that whereas human erythrocytes at rest have a diameter of approxi mately 7. 5 /-tm, nutritive capillaries have diameters ranging from 3-5 /-tm, and chapters in section A give an account of the ways in which the red cell can undergo deformation to permit capillary perfusion and the maintenance of the microcirculation.




Clinical Blood Rheology


Book Description

Published in 1988: Study of blood flow properties (rheology) has attracted growing interest from clinicians in recent years. A United Kingdom meeting and a European meeting in 1979 resulted in previous publications summarizing the literature up to that time.




Blood Viscosity


Book Description




Red Blood Cell Aggregation


Book Description

Red blood cells in humans—and most other mammals—have a tendency to form aggregates with a characteristic face-to-face morphology, similar to a stack of coins. Known as rouleaux, these aggregates are a normally occurring phenomenon and have a major impact on blood rheology. What is the underlying mechanism that produces this pattern? Does this really happen in blood circulation? And do these rouleaux formations have a useful function? The first book to offer a comprehensive review of the subject, Red Blood Cell Aggregation tackles these and other questions related to red blood cell (RBC) aggregates. The book covers basic, clinical, and physiological aspects of this important biophysical phenomenon and integrates these areas with concepts in bioengineering. It brings together state-of-the-art research on the determinants, mechanisms, and measurement and effects of RBC aggregation as well as on variations and comparative aspects. After an introductory overview, the book outlines factors and conditions that affect RBC aggregation. It presents the two hypotheses—the bridging model and the depletion model—that provide potential mechanisms for the adhesive forces that lead to the regular packing of the cells in rouleaux formations. The book also reviews the methods used to quantify RBC aggregation in vitro, focusing on their importance in clinical practice. Chapters discuss the effect of RBC aggregation on the in vitro rheology of blood as well as on tube flow. The book also looks at what happens in the circulation when red blood cells aggregate and examines variations due to physiological and pathophysiological challenges. The concluding chapter explores the formation of red blood cell aggregates in other mammals. Written by leading researchers in the field, this is an invaluable resource for basic science, medical, and clinical researchers; graduate students; and clinicians interested in mammalian red blood cells.




Clinical Blood Rheology


Book Description

Published in 1988: Study of blood flow properties (rheology) has attracted growing interest from clinicians in recent years. A United Kingdom meeting and a European meeting in 1979 resulted in previous publications summarizing the literature up to that time.




Clinical Hemorheology


Book Description

The task the editors have set themselves is to survey the field of clinical hemorheology from basic principles to up-to-date research. It is only in a new science like this that it is possible to span the whole field in a book of this size. Hemorheology, as a new approach to the study and management of a wide range of circulatory diseases, is now beginning to appear with increasing frequency in general as well as specialized medical journals. Hemorheology is also just beginning to creep into the undergraduate medical curriculum. Therefore, the majority of graduate doctors are unequipped to assess the place of hemorheology in the overall framework of circulatory physiology and pathology or to assess its relevance to their everyday practice. It is hoped that this book will fill this gap. The approach of the book is interdisciplinary. The first part deals with basic principles of blood flow, circulation and hemorheology. It has been written with the general doctor in mind, who has no special knowledge of hemodynamics and rheological concepts, terminology or methodology. To maintain the emphasis on practical clinical applications, all the chapters in the second part of the book have been written by clinical specialists practicing in the individual areas of disease. The book is so designed that clinicians may be able to read the relevant chapters in the second part of the book in isolation, using the basic science aspects contained in the first part of the book as reference chapters.




Blood Viscosity and Shock


Book Description

The hemodynamic significance of the flow properties of blood was put into perspective only during the past decade. Advances in modern technologies today allow the quantitative analy­ sis of the fluidity of blood and its components under conditions approximating the flow in vivo, particularly those in the microcirculation. The hematocrit is the most important of the determinants of blood fluidity (reciprocal value of blood viscosity); acute increases in the hematocrit exert deleterious effects on circulation and oxygen transport owing to impaired fluidity of blood. High viscosity of plasma due to hyper- or dysproteinemias initiates the microcirculatory dysfunctions in hyperviscosity syndromes. Furthermore, the fluidity or deformability of red cells might be critically diminished and therefore cause redistribution of blood elements and adversely affect the resistance to flow within the microvessels. In low­ flow states blood fluidity most likely becomes the key determinant for microvessel perfu­ sion, overriding the neural and local metabolic control mechanisms operative at physiological conditions to adjust blood supply to tissue demand. Microcirculatory disturbances are there­ fore encountered whenever driving pressures are reduced, as in shock or hypotension, and distal to stenoses of macrovessels, but also in hemoconcentration due to plasma volume con­ traction, polycythemia, leukemia, and dysproteinemia. Based on experimental studies exploring the possibilities and limitations, with regard to improving the fluidity of blood by reducing the hematocrit, the concept of intentional hemo­ dilution has been introduced to clinical medicine.




Handbook of Hemorheology and Hemodynamics


Book Description

This publication primarily focuses on the macro- and micro-rheological behavior of blood and its formed elements, on interactions between the formed elements and blood vessel walls, and on the microvascular aspects of hemodynamics. 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. Sections of the Handbook include History of Hemorheology; Hemorheology, covering basic aspects, blood composition, blood rheology, cell mechanics, pathophysiology, methods and comparative studies; Hemodynamics, covering basic principles, microcirculation, in vivo effects, endothelium and methods; and Clinical Aspects of Hemorheology, covering hyperviscosity, clinical significance and treatment. The goal is to foster greater interchange between workers in the fields so as to promote collaborative efforts and, hopefully, improved health. In selecting topics for this handbook the editors have attempted to provide a general overview of both basic science and clinical hemorheology and hemodynamics. 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. 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. The editors of the handbook have each been active in the fields of bio- and hemorheology for many years, and have published extensively. They have successfully achieved their objective to publish a well-written and well-edited handbook that will be valuable for researchers and students in the field.




Clinical Hemorheology


Book Description

The task the editors have set themselves is to survey the field of clinical hemorheology from basic principles to up-to-date research. It is only in a new science like this that it is possible to span the whole field in a book of this size. Hemorheology, as a new approach to the study and management of a wide range of circulatory diseases, is now beginning to appear with increasing frequency in general as well as specialized medical journals. Hemorheology is also just beginning to creep into the undergraduate medical curriculum. Therefore, the majority of graduate doctors are unequipped to assess the place of hemorheology in the overall framework of circulatory physiology and pathology or to assess its relevance to their everyday practice. It is hoped that this book will fill this gap. The approach of the book is interdisciplinary. The first part deals with basic principles of blood flow, circulation and hemorheology. It has been written with the general doctor in mind, who has no special knowledge of hemodynamics and rheological concepts, terminology or methodology. To maintain the emphasis on practical clinical applications, all the chapters in the second part of the book have been written by clinical specialists practicing in the individual areas of disease. The book is so designed that clinicians may be able to read the relevant chapters in the second part of the book in isolation, using the basic science aspects contained in the first part of the book as reference chapters.




Red Cell Membrane Transport in Health and Disease


Book Description

51 worldwide leading experts in the field of erythrocyte research contributed to this first book on transport processes in red blood cells. It explains the latest findings on the basis of well-established principles, in an accessibly structured and carefully organized compilation.