Search results for "Circulation"
showing 10 items of 1137 documents
Stimulation of regional lymphatic and blood flow by epicutaneous oxazolone.
2002
The application of the epicutaneous antigen oxazolone results in persistent induration and erythema; however, the relative changes in lymph and blood flow in the inflammatory skin are largely unknown. To define the contribution of lymph and blood flow to the clinical appearance of cutaneous inflammation, we studied the sheep ear after the application of oxazolone. As a model for the study of these changes, the sheep ear had several experimental advantages: 1) a simplified superficial vascular network, 2) defined lymphatic drainage, and 3) an avascular and alymphatic cartilaginous barrier. Lymph flow was continuously monitored by cannulation of the prescapular efferent lymph duct. Blood flo…
Microcirculatory alterations in a mongolian gerbil sinus-vein thrombosis model
2001
Summary Background and purpose. The pathophysiology of sinus-vein thrombosis (SVT) is still controversial in patients and experimental animals, the microcirculatory alterations in particular. This study was designed to develop a new sinus-vein thrombosis model and to further elucidate pathophysiological events such as the relationship between local and regional cerebral blood flow and haemoglobin oxygen saturation (HbSO2), changes of the microvasculature, leukocyte behaviour and brain tissue damage. Methods. In a first experimental series, animals were divided into two groups which resulted from different procedures of inducing SVT. In the SSS middle occlusion group (SMO group), SVT was ind…
Cerebral blood flow alterations in a rat model of cerebral sinus thrombosis.
1993
Outcome from sinus vein thrombosis is very variable, with symptoms from headache to coma. Experimental findings suggest that an involvement of cortical veins is necessary to affect the cerebral microcirculation. Laser Doppler flowmetry was used to investigate the regional and temporal changes in local cortical blood flow after experimental occlusion and thrombosis of the superior sagittal sinus and tributary cortical veins in rats. Thrombosis was induced by slow injection of kaolin-cephalin suspension after frontal and caudal ligation of the sagittal sinus in rats. Local cerebral blood flow was measured by laser Doppler flowmetry and correlated with parenchymal damage found 24 hours after i…
Plastic foil technique attenuates inflammation in mesenteric intravital microscopy.
2000
Abstract Background. Interpretation of intravital microscopic observations is complicated by the “inflammatory”-type response to the trauma inflicted on the tissue by the surgical preparation. The present study evaluates different experimental conditions for prolonged observations of the mesenteric microcirculation in the rat. Methods. The mesentery was exteriorized through a median laparotomy and subjected to an organ bath or a modified plastic foil technique. Hemodynamic, metabolic, respiratory, and microcirculatory data were analyzed. Results. In contrast to the plastic foil technique, which yielded stable baseline values over a 5-h observation period, venular velocity and wall shear rat…
Inflammation-responsive focal constrictors in the mouse ear microcirculation
2006
In many capillary exchange beds, blood flow is locally regulated by precapillary sphincter-like activity. In this study, we used intravascular tracers and scanning electron microscopy to investigate precapillary blood flow regulation in the mouse ear. Gelatin ink injections of the normal mouse ear demonstrated 6.8 +/- 2.3 axial vessels with a cutoff of detectable tracer in the early branches: 19 +/- 11 focal constrictions were observed along the 1st to 5th order branches of the axial vessels. A perfusion tracer consisting of biotinylated anti-endothelial lectins (Ricinus Communis Agglutin, Lycopersicon Esculentum and Griffonia Simplicifolia) was circulated for 30 min under physiological con…
Bridging Mucosal Vessels Associated with Rhythmically Oscillating Blood Flow in Murine Colitis
2007
Oscillatory blood flow in the microcirculation is generally considered to be the result of cardiopulmonary influences or active vasomotion. In this report, we describe rhythmically oscillating blood flow in the bridging vessels of the mouse colon that appeared to be independent of known biological control mechanisms. Corrosion casting and scanning electron microscopy of the mouse colon demonstrated highly branched bridging vessels that connected the submucosal vessels with the mucosal plexus. Because of similar morphometric characteristics (19 +/- 11 microm vs. 28 +/- 16 microm), bridging arterioles and venules were distinguished by tracking fluorescent nanoparticles through the microcircul…
Fine structural features of the cerebral microvasculature in hydrocephalic human infants: correlated clinical observations.
1989
Four of 30 human cerebral cortex biopsies from infants ranging from four days to about ten years treated for hydrocephalus by shunt operations are described paying special attention to the vascular structures. The biopsy specimens were studied in semi-thin and ultrathin sections. Attention is drawn to the role of pinocytotic vesicles found in capillaries and smaller vessels as a possible transcellular route for the hydrocephalic oedema resolution. No intercellular dehiscences or the so called blisters were observed. With the passage of time, the number of membrane bound vesicles increased and arrays of pinocytotic vesicles were discernible both on the abluminal as well as luminal aspect of …
Expression of p53 Protein and Tumor Angiogenesis as Prognostic Factors in Nasopharyngeal Carcinoma Patients.
2002
The objective of this study was to evaluate the possible prognostic significance of p53 protein overexpression and tumor angiogenesis (TA) in nasopharyngeal carcinoma (NPC) patients, together with other clinicopathological variables. Forty-two NPC patients were evaluated in relation to survival. Nuclear p53 overexpression in neoplastic and endothelial cells was detected by immunohistochemistry (IHC) with the monoclonal antibody DO-7 and the polyclonal antibody against factor VIII-related antigen, respectively. Thereafter, we evaluated p53 cases in order to determine their nuclear immunoreactivity from negative (-) to positive (+, ++, +++). In addition, microvessels were counted in the most …
C1-esterase inhibitor reduces infarct volume after cortical vein occlusion.
1999
In order to clarify the role of complement as a mediator of cerebral infarct growth, we inhibited the classical complement activation pathway in a photochemical cortical vein occlusion model. Immediately after occlusion, rats were infused with either 0.9% saline (vehicle), or C1-esterase inhibitor (C1-INH) over 30 min. Regional cerebral blood flow (rCBF) decreased after occlusion, and was about 50% of baseline after 2 h. No difference was noted between experimental groups. Mean arterial blood pressure (MABP) and arterial blood gases were likewise unaffected by the treatment. However, administration of C1-INH had significantly reduced infarct volume by 72%, as evaluated after 5 days survival…
Prolonged Cerebral Circulation Time Is the Best Parameter for Predicting Vasospasm during Initial CT Perfusion in Subarachnoid Hemorrhagic Patients
2016
Purpose We sought to imitate angiographic cerebral circulation time (CCT) and create a similar index from baseline CT perfusion (CTP) to better predict vasospasm in patients with subarachnoid hemorrhage (SAH). Methods Forty-one SAH patients with available DSA and CTP were retrospectively included. The vasospasm group was comprised of patients with deterioration in conscious functioning and newly developed luminal narrowing; remaining cases were classified as the control group. The angiography CCT (XA-CCT) was defined as the difference in TTP (time to peak) between the selected arterial ROIs and the superior sagittal sinus (SSS). Four arterial ROIs were selected to generate four correspondin…