1,721,002 research outputs found
Is there a fetal origin of peripheral vascular disease?
No full textPeripheral vascular disease (PVD) is an atherosclerotic disease of the distal arterial system typically affecting the lower limbs. This syndrome encompasses a wide range of patients from those with asymptomatic arterial narrowing to those with intermittent claudication, and at the extreme end of the spectrum, patients with critical limb ischaemia and gangrene. The common pathophysiological mechanisms underlying the development of PVD and other atherosclerotic diseases are reflected in the fact that patients often have concomitant coronary artery and cerebrovascular disease. Over the last 20 years, a number of studies have established the importance of birth weight as a determinant of both coronary heart disease and cerebrovascular mortality.1,2 By contrast there has been very little work investigating the possible influence of the prenatal environment on the later development of peripheral vascular disease. In this review, we will summarise the epidemiological work conducted on peripheral vascular disease. In addition, we will appraise the evidence that birth weight is associated with the development of this disease. Finally, we will analyse the possible mechanisms underlying such an association using the information gained from both human and animal studies
Red blood cell migration in microvessels
No full textRed blood cell (RBC) migration effects and RBC–plasma interactions occurring in microvessel blood flow have been investigated numerically using a shear-induced particle migration model. The mathematical model is based on the momentum and continuity equations for the suspension flow and a constitutive equation accounting for the effects of shear-induced RBC migration in concentrated suspensions. The model couples a non-Newtonian stress/shear rate relationship with a shear-induced migration model of the suspended particles in which the viscosity is dependent on the haematocrit and the shear rate (Quemada model). The focus of this paper is on the determination of the two phenomenological parameters, Kc and K?, in a diffusive flux model when using the non-Newtonian Quemada model and assuming deformable particles. Previous use of the diffusive flux model has assumed constant values for the diffusion coefficients which serve as tuning parameters in the phenomenological equation. Here, previous data [1 and 16] is used to develop a new model in which the diffusion coefficients depend upon the tube haematocrit and the dimensionless vessel radius for initially uniform suspensions. This model is validated through previous publications and close agreement is obtained
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