Search results for "microcirculation"
showing 10 items of 319 documents
Physiological properties of malignant tumours
1992
It is generally accepted that tumour microcirculation, blood flow, oxygen and nutrient supply, tissue pH distribution, and the bioenergetic status--factors which are usually closely linked and which define the so-called metabolic microenvironment--can markedly influence the therapeutic response of malignant tumours to conventional irradiation, chemotherapy, other non-surgical treatment modalities, and the cell proliferation activity within the tumours. Currently available information on the parameters defining the metabolic micromilieu in human tumours is presented in this paper. According to these data, significant variations in these relevant factors are likely to occur between different …
Expression of the endothelial markers PECAM-1, vWf, and CD34 in vivo and in vitro.
2002
EC culture models are essential to study pathological alterations of endothelial cells (ECs) in pulmonary vascular diseases under standardized conditions. Nevertheless, little is known about the spectrum of alterations of vessel-specific endothelial phenotypes in monolayer cultures. For the comparative study of endothelial markers in vivo and in vitro we investigated immunohistochemically the expression of PECAM-1, vWf, and CD34 by pulmonary ECs in vivo and in stimulated/unstimulated human umbilical vein endothelial cells (HU-VEC) and human pulmonary microvascular endothelial cells (HPMEC). In vivo, vessel type-specific expression patterns were found for vWf and CD34, while PECAM-1 was homo…
Microvascular in vivo assessment of reperfusion injury: significance of prostaglandin E1 and I2 in postischemic “no-reflow” and “reflow-paradox”
2004
Microvascular ischemia-reperfusion (I/R) injury is characterized by failure of capillary perfusion ("no-reflow") and reoxygenation-associated phenomena ("reflow-paradox"), including activation of leukocyte-endothelium interaction with cytotoxic mediator-induced loss of endothelial integrity. The objectives of this study were to elucidate the impact of both prostaglandins E(1) (PGE(1)) and I(2) (PGI(2)) in microvascular reperfusion injury, with special focus on the distinct pathophysiology of no-reflow- and reflow-paradox phenomena.By use of the hamster dorsal skinfold preparation and in vivo fluorescence microscopy, the microcirculation of a striated skin muscle was assessed before 4 h of p…
Inflammation-Induced Intussusceptive Angiogenesis in Murine Colitis
2010
Intussusceptive angiogenesis is a morphogenetic process that forms new blood vessels by the division of a single blood vessel into two lumens. Here, we show that this process of intraluminal division participates in the inflammation-induced neovascularization associated with chemically induced murine colitis. In studies of both acute (4-7 days) and chronic (28-31 days) colitis, intravital microscopy of intravascular tracers demonstrated a twofold reduction in blood flow velocity. In the acute colitis model, the decreased velocity was associated with marked dilatation of the mucosal plexus. In contrast, chronic inflammation was associated with normal caliber vessels and duplication (and trip…
Automated Measurement of Microcirculatory Blood Flow Velocity in Pulmonary Metastases of Rats
2014
Because the lung is a major target organ of metastatic disease, animal models to study the physiology of pulmonary metastases are of great importance. However, very few methods exist to date to investigate lung metastases in a dynamic fashion at the microcirculatory level, due to the difficulty to access the lung with a microscope. Here, an intravital microscopy method is presented to functionally image and quantify the microcirculation of superficial pulmonary metastases in rats, using a closed-chest pulmonary window and automated analysis of blood flow velocity and direction. The utility of this method is demonstrated to measure increases in blood flow velocity in response to pharmacologi…
Neonatal form of nemaline myopathy, muscle immaturity, and a microvascular injury.
1990
An infant with a neonatal form of nemaline myopathy showed ultrastructural features of muscle immaturity. Immaturity was characterized by an abnormal presence of myotubes, as well as cells in clusters within a common basement membrane and a great number of satellite cells adhering to very small muscle fibers. In addition, degenerative changes and a severe microvascular lesion were observed. The pathologic findings in the muscle of this patient were those of neonatal nemaline myopathy complicating severe microvascular injury, possibly induced by an unknown toxic agent. ( J Child Neurol 1990;5:122-126).
HETEROGENEOUS OXYGEN TRANSPORT WITHIN MALIGNANT TUMORS
1981
Publisher Summary This chapter discusses the heterogeneous oxygen transport within malignant tumors. Many solid tumors disturbances in the vascularization and in the microcirculation generally lead to distinct restrictions in the convective and diffusive transport. Beyond that, a heterogeneous distribution of the transport conditions develops causing an insufficient and heterogeneous substrate supply as well as an inadequate drainage of wastes. As one of the compulsory manifestations, a poor and heterogeneous oxygen supply becomes more extensively evident with increasing tumor size or age. The polarographic measurements of the local tissue pO 2 values in animal tumors show that very low oxy…
Clinical disorders responsible for plasma hyperviscosity and skin complications
2017
In this brief review, we have examined some clinical disorders which are associated to an altered hemorheological profile and at times accompanied by skin ulcers. This skin condition may be, in fact, observed in patients with primary plasma hyperviscosity such as multiple myeloma, Waldenstrom macroglobulinemia, cryoglobulinemia, cryofibrinogenemia, dysfibrinogenemia and connective tissue diseases. It must be underlined that the altered hemorheological pattern is not the only responsible for this skin complication but, as it worsens the microcirculatory flow, it contributes to determine the occurrence of the skin ulcers.
Differential adhesion of polymorphous neutrophilic granulocytes to macro- and microvascular endothelial cells under flow conditions.
2002
<i>Objective:</i> As one of the important active barriers in the human organism, endothelial cells (EC) play a central role in the biological reaction to a variety of stimuli, e.g. during the induction and regulation of inflammation, as well as in the reaction to transplantation and biomaterial implantation. In the study of endothelial function, the most widely used in vitro model is that of human umbilical vein EC (HUVEC), i.e. an EC type of embryonic and macrovascular origin. However, many of the important pathological processes occur at microvascular level, thus questioning the validity of the HUVEC model. Moreover, the morphological and functional heterogeneity of the endoth…
Perspectives in Clinical Hemorheology and Microcirculation: Review of the Conference of the German Society for Clinical Microcirculation and Hemorheo…
2011
During the 29th conference of the German Society for Clinical Microcirculation and Hemorheology – held in the Freie Universitat Berlin a broad range of different topics of experimental and clinical studies in the field were presented. A special spotlight was dedicated to the Conference President’s (Prof. Dr. J. Plendl, Head of the Department of Veterinary Anatomy) scientific area “Anatomical and Experimental Microcirculation” [5, 6, 9, 13]. Of special interest were the angiogenetic studies: Examinations of the influence of PDGF-BB on adipose-tissue derived stem cells and how these influence angiogenesis [9] and the angiogenesis and healing with non-shrinking, fast degradable PLGA/CaP scaffo…