Search results for "blood vessel"

Collagen-embedded hydroxylapatite–beta-tricalcium phosphate–silicon dioxide bone substitute granules assist rapid vascularization and promote cell gr…

2010

In the present study we assessed the biocompatibility in vitro and in vivo of a low-temperature sol-gel-manufactured SiO(2)-based bone graft substitute. Human primary osteoblasts and the osteoblastic cell line, MG63, cultured on the SiO(2) biomatrix in monoculture retained their osteoblastic morphology and cellular functionality in vitro. The effect of the biomaterial in vivo and its vascularization potential was tested subcutaneously in Wistar rats and demonstrated both rapid vascularization and good integration within the peri-implant tissue. Scaffold degradation was progressive during the first month after implantation, with tartrate-resistant acid phosphatase-positive macrophages being …

Comprehensive Analysis of VEGFR2 Expression in HPV-Positive and -Negative OPSCC Reveals Differing VEGFR2 Expression Patterns

2021

VEGF signaling regulated by the vascular endothelial growth factor receptor 2 (VEGFR2) plays a decisive role in tumor angiogenesis, initiation and progression in several tumors including HNSCC. However, the impact of HPV-status on the expression of VEGFR2 in OPSCC has not yet been investigated, although HPV oncoproteins E6 and E7 induce VEGF-expression. In a series of 56 OPSCC with known HPV-status, VEGFR2 expression patterns were analyzed both in blood vessels from tumor-free and tumor-containing regions and within tumor cells by immunohistochemistry using densitometry. Differences in subcellular colocalization of VEGFR2 with endothelial, tumor and stem cell markers were determined by doub…

Cardiac output following fetoscopic coagulation of major placental vessels in fetal sheep.

2008

Objectives To measure changes in cardiac output (CO) after partial cord occlusion in fetal sheep in order to investigate pathophysiological fetal adaptation mechanisms in a simulated acute placental insufficiency model under standardized conditions, with the aim of finding relevant methods for monitoring human fetuses during stress situations. Methods We used minimally invasive, percutaneous endoscopic techniques to close umbilical vessels in mid-gestational fetal sheep. Placental blood flow was reduced by preferentially closing first arterial and then the concomitant venous umbilical vessels within a short time interval. The investigations were carried out on 11 pregnant ewes at a median g…

Preclinical carotid atherosclerosis enhances the global cardiovascular risk and increases the rate of cerebro- and cardiovascular events in a five-ye…

2009

AIM: To evaluate if the intima-media thickening (IMT) and asymptomatic carotid plaque (ACP), as expression of carotid preclinical atherosclerosis (pre-ATS), can provide further information on the global cardiovascular risk (GCVR). METHODS: We studied 454 asymptomatic subjects, with a cluster of risk factors (RF), and evaluated the incidence of a first cardiovascular (CV) event in a five-year follow-up. The subjects at admission were subdivided in three groups of risk. RESULTS: Events occurred in 38% of subjects at high risk, in 13% and 6% of subjects at intermediate and low risk (p<0.003). Among evaluated parameters, carotid pre-ATS was a predictive marker of CV events (OR 2.7, 95% IC 1.4-5…

External stenting with a new polyester mesh reduces neointimal hyperplasia of vein grafts in a sheep model.

2007

Objective External stents placed around vein grafts have demonstrated effectiveness in reducing neointimal hyperplasia by preventing distension of the thin-walled vein grafts when exposed to arterial pressure. However, the ideal stent material has yet to be defined. The following study investigates the short- and long-term effects of an innovative polyester mesh stent designed with optimized adaptation of circumferential compliance. Methods Following in vitro definition of the ideal macro-porous polyester stent material, a total of 12 sheep underwent implantation of bilateral carotid artery vein graft bypasses. In six sheep, the short-term outcome (four weeks of implantation) was investigat…

Ceramide Mediates Acute Oxygen Sensing in Vascular Tissues

2014

AbstractAims: A variety of vessels, such as resistance pulmonary arteries (PA) and fetoplacental arteries and the ductus arteriosus (DA) are specialized in sensing and responding to changes in oxygen tension. Despite opposite stimuli, normoxic DA contraction and hypoxic fetoplacental and PA vasoconstriction share some mechanistic features. Activation of neutral sphingomyelinase (nSMase) and subsequent ceramide production has been involved in hypoxic pulmonary vasoconstriction (HPV). Herein we aimed to study the possible role of nSMase-derived ceramide as a common factor in the acute oxygen-sensing function of specialized vascular tissues. Results: The nSMase inhibitor GW4869 and an anticera…

Reinterpreting the Magnetic Resonance Signs of Hemodynamic Impairment in the Brains of Multiple Sclerosis Patients From the Perspective of a Recent D…

2010

Multiple sclerosis patients examined with perfusion magnetic resonance (MR) imaging techniques have been found to have patterns of abnormal blood flow. These include prolonged mean transit time, a trend toward decreased cerebral blood flow in the area of plaques, and decreased cerebral blood flow and prolonged mean transit time within normal-appearing white matter. In-creased cerebral blood flow and volume and decreased mean transit time (compared with the baseline values before the relapse) were found to precede the development of plaques. In addition, susceptibility-weighted imaging utilizing deoxyhemoglobin as the contrast has revealed that venous blood in cerebral veins of multiple scle…

The use of Endurant stent-graft for abdominal aortic aneurysm: the story about extension of instruction for use with persistent good results of stent…

2012

The Endurant stent-graft (Medtronic, Inc., Minneapolis, MN, USA) is a latest generation device for the treatment of abdominal aortic aneurysm. The idea behind designing such a graft came from the intention to broad the instruction for use (IFU) and to enable it to treat more challenging anatomy including the 10mm neck lengths, and more severe suprarenal and infrarenal angulations. Endurant stent-graft has active fixation through suprarenal stent with anchoring pins to provide migration resistance, optimized heights of stents and spacing between them for improved flexibility and conformability, low-profile delivery system with hydrophilic coating and controlled simple deployment mechanism. S…

2017

We propose a mesh-free and discrete (particle-based) multi-physics approach for modelling the hydrodynamics in flexible biological valves. In the first part of this study, the method is successfully validated against both traditional modelling techniques and experimental data. In the second part, it is further developed to account for the formation of solid aggregates in the flow and at the membrane surface. Simulations of various types of aggregates highlight the main benefits of discrete multi-physics and indicate the potential of this approach for coupling the hydrodynamics with phenomena such as clotting and calcification in biological valves.

Thromboinflammation and Vascular Dysfunction.

2018

Thromboinflammation and vascular dysfunction are inseparably combined with the innate and the adaptive immune response. While the role of this interplay has gained considerable attention in the arena of atherosclerosis/atherothrombosis and in deep vein thrombosis, its role in other forms of vascular disease and risk factors is currently emerging. In this brief review, we will focus on thromboinflammation with regard to cytokine signalling as well as on the novel role of a vascular coagulation-inflammatory circuit in arterial hypertension.Thrombo-Inflammation und vaskuläre Dysfunktion sind untrennbar mit dem angeborenen und dem erworbenen Immunsystem verbunden. Dieses Zusammenspiel wurde im …