Effect of unilateral nephrectomy on the localization of aortic sudanophilic lesions in cholesterol-fed rabbits

Roach, Margot R.; Fletcher, Joan

doi:10.1016/0021-9150(76)90088-5

Cited by 15 publications

(3 citation statements)

References 8 publications

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“…There is compelling evidence that early atherosclerotic lesions most often originate near arterial bends and branch sites, where complex blood flow patterns occur. This finding, together with observations that experimental perturbations in flow can initiate or redistribute lesions, 1,2 strongly implicates local hemodynamics in atherogenesis. More specifically, exhaustive study of selected arterial sites, eg, the carotid bifurcation, has provided evidence that low and/or fluctuating shear stresses are proatherogenic.…”

mentioning

confidence: 59%

Assembly and Reorientation of Stress Fibers Drives Morphological Changes to Endothelial Cells Exposed to Shear Stress

Noria

McCue

et al. 2004

The American Journal of Pathology

152

122

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Fluid shear stress greatly influences the biology of vascular endothelial cells and the pathogenesis of atherosclerosis. Endothelial cells undergo profound shape change and reorientation in response to physiological levels of fluid shear stress. These morphological changes influence cell function; however, the processes that produce them are poorly understood. We have examined how actin assembly is related to shear-induced endothelial cell shape change. To do so, we imposed physiological levels of shear stress on cultured endothelium for up to 96 hours and then permeabilized the cells and exposed them briefly to fluorescently labeled monomeric actin at various time points to assess actin assembly. Alternatively, monomeric actin was microinjected into cells to allow continuous monitoring of actin distribution. Actin assembly occurred primarily at the ends of stress fibers, which simultaneously reoriented to the shear axis, frequently fused with neighboring stress fibers, and ultimately drove the poles of the cells in the upstream and/or downstream directions. Actin polymerization occurred where stress fibers inserted into focal adhesion complexes, but usually only at one end of the stress fiber. Neither the upstream nor downstream focal adhesion complex was preferred. Changes in actin organization were accompanied by translocation and remodeling of cell-substrate adhesion complexes and transient formation of punctate cell-cell adherens junctions. These findings indicate that stress fiber assembly and realignment provide a novel mode by which cell morphology is altered by mechanical signals.

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mentioning

confidence: 59%

Assembly and Reorientation of Stress Fibers Drives Morphological Changes to Endothelial Cells Exposed to Shear Stress

Noria

McCue

et al. 2004

The American Journal of Pathology

152

122

View full text Add to dashboard Cite

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“…22 In rabbits that were fed cholesterol, lesions were observed at the same site, and the distribution of lesions was altered by surgical modifications that would have altered the pattern of blood flow. 23 In dogs there was a major difference in the velocity profiles measured at site 1 and those at site 3, which was four diameters downstream. In humans lesions occur within two diameters of the ostium, 7 -8 i.e., the region within which flow separation was observed in the dogs.…”

Section: Bifurcation Geometry and Velocity Profilesmentioning

confidence: 99%

Blood velocity profiles in the origin of the canine renal artery and their relevance in the localization and development of atherosclerosis.

Yamamoto

Tanaka

Jones

et al. 1992

Arterioscler Thromb

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Using a 20-MHz 80-channel pulsed Doppler velocimeter and 30 -MHz high-resolution echo ultrasound, we investigated the in vivo hemodynamlcs at the origin of the renal artery by measuring the velocity profiles and bifurcation geometry of a surgically exposed left renal artery in 10 anesthetized dogs. The angle between the aorta and the renal artery ranged from 60° to 90° (mean, 84°) although the bifurcation did not lie in a single anterodorsal plane and the diameter of the renal artery ranged from 1-5 to 3.5 mm (mean, 2.4 mm). Despite different geometries, the velocity profiles in the different aortorenal bifurcations were similar. Although regions of reverse velocity were observed, the net flow in the renal artery was in the forward direction throughout the cardiac cycle. The peak Reynolds' number was 486±63. The velocity profiles in the proximal renal artery in the plane parallel to the bifurcation showed velocity vectors directed toward the caudal wall throughout the cardiac cycle. Reverse flow, indicating flow separation, was observed near the cranial wall even during systole. When the probe was placed on the cranial wall perpendicular to the wall, a velocity component from the cranial side to the caudal side was observed. At a distance of four diameters from the renal ostia, velocity profiles were almost parabolic These results indicate that the velocity pattern near the cranial wall at the renal ostia, at which atherosclerotic lesions are prone to develop, are characterized by 1) a low time-averaged shear rate, 2) separation of the flow, and 3) a time-varying oscillation of the flow. arly atherosclerotic lesions tend to be found at bifurcations and the curved regions of arteries, and it has been suggested that hemodynamic factors play an important role in lesion development. This hypothesis is supported by the rapidly growing number of effects that blood flow appears to exert on the walls of blood vessels.1 Particular blood flow patterns may influence the shape and orientation of endothelial cells, 2 the release of various autacoids, 3 -4 and the mass-transport properties of the vessel wall.' Some of the effects appear to depend on not only the magnitude of the wall shear stress but also its time-and directiondependent characteristics. 6 From the Departments of Urology and Medical Engineering

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“…1 There is strong evidence that arterial geometry is an important factor affecting the pattern of flow, 2 ' 3 the orientation of endothelial cell nuclei, 4 the initial deposition sites of atheroma, 5 and the localization of cerebral aneurysms. 6 In this paper we will focus on possible reasons for the localization of saccular aneurysms in relation to the geometry of the apex or branching region of cerebral arterial bifurcations.…”

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confidence: 99%

Shape changes at the apex of isolated human cerebral bifurcations with changes in transmural pressure.

Macfarlane¹,

Canham²,

Roach³

1983

Stroke

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SUMMARY The geometry of arterial bifurcations appears to play a significant role in the development of vascular disease. We have investigated the changes in bifurcation geometry with changes in distending pressure over the range 0.0 to 190.0 mm Hg. Five cerebral arterial bifurcations from human subjects were studied. The investigation focussed on the shape and on changes in the shape of the leading edge of the flow divider (internal apical curve). The curve outline at each transmural pressure increment (each 10.0 mm Hg) was photographed and digitized. The curves were plotted serially on an expanded scale. Visual comparison of the curves indicated flattening in the central region and broadening of the shoulders of the curves with increasing transmural pressure. Regression analysis using second order polynomials was used to obtain coefficients for equations defining short, overlapping segments of each curve. Twenty-four coordinates were used for each successive regression. Each curve was characterized by 85 to 100 digitized coordinates. The regression equations for each curve were used to calculate the curvature parameter, K, and the radius of curvature, R. Three of the five bifurcations demonstrated a negative correlation of K with increasing transmural pressure (p < .001). This result supports the visual observation that the internal apical curve flattens with increasing transmural pressure. Flattening of the internal apical curve together with thinning of the arterial wall with increasing transmural pressure would contribute to a stress concentration at the apex of a cerebral bifurcation. This stress concentration would be more pronounced in the presence of a medial gap at the apex of the bifurcation. It is on or near this region of stress concentration that aneurysms develop. Stroke, Vol 14, No 1, 1982 IN RECENT YEARS there has been a growing awareness of the importance of vascular geometry and its role in the development of vascular disease. 1 There is strong evidence that arterial geometry is an important factor affecting the pattern of flow, 2 ' 3 the orientation of endothelial cell nuclei, 4 the initial deposition sites of atheroma, 5 and the localization of cerebral aneurysms. 6 In this paper we will focus on possible reasons for the localization of saccular aneurysms in relation to the geometry of the apex or branching region of cerebral arterial bifurcations. Hassler 6 and Stehbens and Ludatscher 7 have reported that cerebral aneurysms develop almost exclusively at the apices of bifurcations. In previous work, Macfarlane et al. 8 have demonstrated in vitro variations in the deformability of the apical region and nonlinear changes in the size of the internal apical curvature in bifurcations of isolated human cerebral arteries subjected to a range of static pressures. The internal apical curve is the outline of the leading edge of the flow divider which separates the parent trunk into the daughter branches. This curve lies in a plane perpendicular to the plane of bifurcation ( fig. 1). It is on or near...

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Effect of unilateral nephrectomy on the localization of aortic sudanophilic lesions in cholesterol-fed rabbits

Cited by 15 publications

References 8 publications

Assembly and Reorientation of Stress Fibers Drives Morphological Changes to Endothelial Cells Exposed to Shear Stress

Assembly and Reorientation of Stress Fibers Drives Morphological Changes to Endothelial Cells Exposed to Shear Stress

Blood velocity profiles in the origin of the canine renal artery and their relevance in the localization and development of atherosclerosis.

Shape changes at the apex of isolated human cerebral bifurcations with changes in transmural pressure.

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