Search results for "microcirculation"

Focal topographic changes in inflammatory microcirculation associated with lymphocyte slowing and transmigration

2001

Microcirculation is the primary mechanism for delivering lymphocytes to inflammatory tissues. Blood flow within microvessels ensures a supply of lymphocytes at the blood-endothelial interface. Whether the structure of the inflammatory microcirculation facilitates lymphocyte transmigration is less clear. To illuminate the microcirculatory changes associated with lymphocyte transmigration, we used intravital videomicroscopy to examine the dermal microcirculation after application of the epicutaneous antigen oxazolone. Intravascular injection of fluorescein-labeled dextran demonstrated focal topographic changes in the microcirculation. These focal changes had the appearance of loops or hairpin…

Evaluation of Oxygen Diffusion Distances in Human Breast Cancer Using Cell Line Specific in Vivo Data: Role of Various Pathogenetic Mechanisms in the…

1988

Radiobiological hypoxia in malignant tumors has been shown to originate (i) from spatial and temporal functional disturbances of tumor microcirculation resulting in a limited convective O2 flux in microregions even in tissue areas exhibiting high vascular densities, and (ii) from morphological abnormalities of the microcirculatory bed leading to a limitation of the diffusive O2 flux. In addition to these pathogenetic mechanisms, systemic factors (anemia, arterial hypoxia) can also play a role in the development of tumor hypoxia.

Monitoring of cortical blood flow: Clinical relevance of experimental laser Doppler studies

1996

Continuous monitoring of cortical blood flow provides real time information of CBF-changes during neurosurgical operations and on the neurointensive care unit. Laser Doppler flowmetry is a continuous, noninvasive technique suitable for measurement of the cortical microcirculation. In a number of experimental studies we have analyzed the characteristics of this method for cortical blood flow monitoring. The high spatial resolution of laser Doppler flowmetry and the heterogeneity of the cortical microvascular network results in a scatter of flow values over a wide range depending on the site of measurement. Data collection from different spots and calculation of frequency histogram may serve …

Relationship Between Size and Oxygenation Status of Malignant Tumors

1983

During advanced phases of malignant growth, there are typical changes in the microvasculature pattern within the tissue of many solid tumors. Partly due to these peculiarities of tumor vascularization, a series of characteristic variations of tumor microcirculation occurs (for a review see 1). These alterations lead not only to marked restrictions and inhomogeneities of both convective and diffusive transport but also to an impairment of the efficiency of antitumor therapies.

Microvessel-like structures from outgrowth endothelial cells from human peripheral blood in 2-dimensional and 3-dimensional co-cultures with osteobla…

2007

Tissue regeneration involves complex processes in the interaction between different cell types that control the process of neo-vascularization. In bone, osteoblasts and bone marrow stem cells provide cue elements for the proliferation of endothelial cells, differentiation of endothelial precursors, and the maturation of a vascular network. In this study, we investigated outgrowth endothelial cells (OECs), a potential source of autologous endothelial cells derived from human peripheral blood, in direct 2-dimensional (2-D) and 3-D co-culture systems with cells relevant for the regeneration of bone tissue, such as osteoblasts. In the co-cultures, OECs were evaluated in terms of their stability…

Murine Microvideo Endoscopy of the Colonic Microcirculation

2007

Natural orifice endoscopy in small animal models has been limited in the past by instrument size and optical performance. In this report, we investigate the feasibility of using a recently developed microvideo endoscopy system to evaluate the colon microcirculation. Using a murine model of acute colitis, microvideo endoscopy was useful in mapping the topography of inflammation as well as identifying relevant structures in the microcirculation. We conclude that natural orifice endoscopy is a useful method for the minimally invasive longitudinal assessment of the colonic mucosal microcirculation.

Intravascular pillars and pruning in the extraembryonic vessels of chick embryos.

2010

To investigate the local mechanical forces associated with intravascular pillars and vessel pruning, we studied the conducting vessels in the extraembryonic circulation of the chick embryo. During the development days 13-17, intravascular pillars and blood flow parameters were identified using fluorescent vascular tracers and digital time-series video reconstructions. The geometry of selected vessels was confirmed by corrosion casting and scanning electron microscopy. Computational simulations of pruning vessels suggested that serial pillars form along pre-existing velocity streamlines; blood pressure demonstrated no obvious spatial relationship with the intravascular pillars. Modeling a Re…

Mortality in patients with hepatocellular carcinoma predicted by six scoring: none is the winner

2007

Oral microcirculation in post-menopause: a possible correlation with periodontitis

2011

doi: 10.1111/j.1741-2358.2011.00608.x Oral microcirculation in post-menopause: a possible correlation with periodontitis Objectives:  The reduction in the level of oestrogen, typical in menopause, has some effect on the health of the oral cavity. In fact, post-menopausal women present more severe periodontal disease than pre-menopausal women. Numerous factors can be held to be responsible for this increase, among which are the effects of oestrogens on the oral epithelium, on the salivary glands, on bone tissue and on the endothelium. Our double blind study aims to evaluate the possible variations in oral microcirculation in post-menopausal women. Methods:  Twenty-seven women in post-menopau…

Margination of Fluorescent Polylactic Acid-Polyaspartamide based Nanoparticles in Microcapillaries In Vitro: the Effect of Hematocrit and Pressure.

2017

The last decade has seen the emergence of vascular-targeted drug delivery systems as a promising approach for the treatment of many diseases, such as cardiovascular diseases and cancer. In this field, one of the major challenges is carrier margination propensity (i.e., particle migration from blood flow to vessel walls); indeed, binding of these particles to targeted cells and tissues is only possible if there is direct carrier–wall interaction. Here, a microfluidic system mimicking the hydrodynamic conditions of human microcirculation in vitro is used to investigate the effect of red blood cells (RBCs) on a carrier margination in relation to RBC concentration (hematocrit) and pressure drop…