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Pulsatile flow

About: Pulsatile flow is a research topic. Over the lifetime, 6278 publications have been published within this topic receiving 149638 citations.


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Journal ArticleDOI
TL;DR: The data suggest fluid flow-induced mobilization of intracellular Ca2+ may contribute to the mechanism by which mechanical loads are transduced by chondrocytes.
Abstract: Fluid flow-induced shear stress results in a variety of morphological and metabolic changes in cultured bovine articular chondrocytes (BAC). However, the mechanism by which the flow signal is transduced into a biological response is unknown. Therefore, we investigated the effects of fluid flow on intracellular Ca2+ concentration ([Ca2+]i) in BAC. Cells loaded with fura 2 were exposed to steady and pulsatile (0.5 Hz) flow at 9, 18, and 34 ml/min in a parallel-plate flow chamber. In response to flow, there was a significant and flow rate-dependent increase in the percentage of cells showing a rise in [Ca2+]i, but no effect on the [Ca2+]i response amplitude. There was no significant difference between the [Ca2+]i responses to steady and pulsatile flow. Mean intracellular Ca2+ response values ranged between 26.2 +/- 1.6 (9 ml/min) and 38.0 +/- 6.8 nM (34 ml/min) above basal [Ca2+]i (81.3 +/- 24.1 nM, n = 90). Removal of extracellular Ca2+ or addition of Gd3+ significantly reduced the percentage of cells responding, suggesting that influx of Ca2+, possibly through mechanosensitive channels, contributes to the rise in intracellular Ca2+. Our data suggest fluid flow-induced mobilization of intracellular Ca2+ may contribute to the mechanism by which mechanical loads are transduced by chondrocytes.

106 citations

Journal ArticleDOI
TL;DR: Quantitative changes in the arterial waveform were found in long-term smokers compared with nonsmoking control subjects, marking the presence of abnormal structure or tone in the peripheral vasculature that affects pulsatile arterial function.

106 citations

Journal ArticleDOI
01 May 1999-Stroke
TL;DR: Venous TCCS can reliably image a significant part of the cerebral venous system and can provide information on venous hemodynamics in normal subjects and pathological cases.
Abstract: Background and Purpose—Transcranial color-coded duplex sonography (TCCS) of intracranial veins and sinuses in adults is a new, emerging application of ultrasonographic imaging. This study reports a standardized examination protocol for venous TCCS and provides reference data for clinical application. Methods—In 130 healthy volunteers (mean age, 45.9±16.9 years; range, 14 to 77 years) the intracranial venous system was examined using frequency-based transtemporal TCCS. Identification rate, blood flow velocity , resistance index, and systolic/diastolic ratio were recorded for each examined venous vessel. Results—Intracranial veins and sinuses show a low pulsatile forward flow with maximal systolic blood flow velocity up to 20 cm/s. Significant side differences of blood flow velocity in the paired venous structures could not be detected. Venous flow velocities decreased with age, whereas resistance indices and systolic/diastolic ratios increased. Women showed higher flow velocities than men. Mean identificat...

105 citations

Journal ArticleDOI
TL;DR: The flow dynamics in two representative models of a terminal aneurysm of the basilar artery under Newtonian and non-Newtonian fluid assumptions are described and their hemodynamics are compared with that of a healthy basilar arteries.
Abstract: Blood flow dynamics under physiologically realistic pulsatile conditions plays an important role in the growth, rupture, and surgical treatment of intracranial aneurysms. The temporal and spatial variations of wall pressure and wall shear stress in the aneurysm are hypothesized to be correlated with its continuous expansion and eventual rupture. In addition, the assessment of the velocity field in the aneurysm dome and neck is important for the correct placement of endovascular coils. This paper describes the flow dynamics in two representative models of a terminal aneurysm of the basilar artery under Newtonian and non-Newtonian fluid assumptions, and compares their hemodynamics with that of a healthy basilar artery. Virtual aneurysm models are investigated numerically, with geometric features defined by beta = 0 deg and beta = 23.2 deg, where beta is the tilt angle of the aneurysm dome with respect to the basilar artery. The intra-aneurysmal pulsatile flow shows complex ring vortex structures for beta = 0 deg and single recirculation regions for beta = 23.2 deg during both systole and diastole. The pressure and shear stress on the aneurysm wall exhibit large temporal and spatial variations for both models. When compared to a non-Newtonian fluid, the symmetric aneurysm model (beta = 0 deg) exhibits a more unstable Newtonian flow dynamics, although with a lower peak wall shear stress than the asymmetric model (beta = 23.2 deg). The non-Newtonian fluid assumption yields more stable flows than a Newtonian fluid, for the same inlet flow rate. Both fluid modeling assumptions, however, lead to asymmetric oscillatory flows inside the aneurysm dome.

105 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023274
2022641
2021170
2020181
2019171
2018189