Search results for "Vasoconstriction"
showing 10 items of 134 documents
Helmet continuous positive airway pressure and prone positioning: A proposal for an early management of COVID-19 patients
2020
In late December 2019, clusters of patients with interstitial pneumonia of unknown cause were reported by some local health facilities in Wuhan (China). The Chinese Centre for Disease Control conducted an epidemiologic and etiologic investigation, leading to the identification of a novel coronavirus (SARS-CoV-2).1, 2 On March 11th, the World Health Organization (WHO) declared the novel coronavirus disease (COVID-19) a pandemic. In the area of Wuhan, COVID-19 mainly affected male patients (around 60%), with a median age of about 50 years; 40% of patients developed Acute Respiratory Distress Syndrome (ARDS) 5% requiring intensive care. The mortality rate was around 2%.3, 4 However, Grasselli …
Relaxant and antiadrenergic effects of ranolazine in human saphenous vein.
2019
Abstract OBJECTIVES Ranolazine improves vascular function in animal models. We evaluate the effects of ranolazine on vascular function and adrenergic response in human saphenous vein. METHODS Rings from 53 patients undergoing coronary artery bypass grafting were mounted in organ baths. Concentration–response curves to ranolazine were constructed in rings precontracted with phenylephrine, endothelin-1, vasopressin, KCl and the thromboxane A2 analogue U-46619. In rings precontracted with phenylephrine, relaxation to ranolazine was tested in the absence and presence of endothelial factors inhibitors, K+ channel blockers and verapamil. The effects of ranolazine on frequency–response and concent…
Oxidative lung injury correlates with one-lung ventilation time during pulmonary lobectomy: a study of exhaled breath condensate and blood.
2015
OBJECTIVES: During lung lobectomy, the operated lung is collapsed and hypoperfused; oxygen deprivation is accompanied by reactive hypoxic pulmonary vasoconstriction. After lung lobectomy, ischaemia present in the collapsed state is followed by expansion–reperfusion and lung injury attributed to the production of reactive oxygen species. The primary objective of this study was to investigate the time course of several markers of oxidative stress simultaneously in exhaled breath condensate and blood and to determine the relationship between oxidative stress and one-lung ventilation time in patients undergoing lung lobectomy. METHODS: This single-centre, observational, prospective study includ…
Target oxygen levels in preterm neonates
2013
To achieve postnatal adaptation newly born infant need to aerate the lungs, reduce pulmonary vascular resistance, and initiate oxygen and carbon dioxide exchange. The cornerstone of newborn resuscitation resides therefore in the establishment of a functional residual capacity and an adequate oxygenation. Recent guidelines have established guidelines concerning oxygen supplementation in preterm infants in the delivery room (DR); however, they are vague and unspecific. Herewith, we will address available information regarding the use of oxygen supplementation in the DR in preterm infants to satisfactorily overcome postnatal adaptation. Introduction: Resuscitation of the newborn is considered …
Neutrophil Adherence to Activated Saphenous Vein and Mammary Endothelium After Graft Preparation
2005
Interaction of circulating leukocytes and vascular endothelium plays an important role in vasoconstriction, endothelial dysfunction, and vascular injury. Dilation procedures of grafts before coronary artery bypass graft surgery might lead to vascular injury and subsequent bypass graft disease.We analyzed in vitro the adherence of fluorescence-labeled polymorphonuclear neutrophils (PMNs) to endothelium of human saphenous vein grafts or internal mammary artery grafts after stimulation with thrombin (0.5 to 2 U/mL) or dilating procedures. Furthermore, we investigated endothelial function of prepared grafts.Thrombin stimulation resulted in a dose-dependent increase of PMN adherence to the endot…
Role of nitric oxide synthase isoforms for ophthalmic artery reactivity in mice.
2014
Abstract Nitric oxide synthases (NOS) are involved in regulation of ocular vascular tone and blood flow. While endothelial NOS (eNOS) has recently been shown to mediate endothelium-dependent vasodilation in mouse retinal arterioles, the contribution of individual NOS isoforms to vascular responses is unknown in the retrobulbar vasculature. Moreover, it is unknown whether the lack of a single NOS isoform affects neuron survival in the retina. Thus, the goal of the present study was to examine the hypothesis that the lack of individual nitric oxide synthase (NOS) isoforms affects the reactivity of mouse ophthalmic arteries and neuron density in the retinal ganglion cell (RGC) layer. Mice defi…
Gathering of aging and estrogen withdrawal in vascular dysfunction of senescent accelerated mice.
2010
The aim of this work was to characterize a mouse model of experimental menopause and cardiovascular aging that closely reflects menopause in women. Senescence accelerated mouse (SAM)-Resistant type 1 (SAMR1, n=30) and SAM-Prone type 8 (SAMP8, n=30) were separated at 5months of age into three groups: 1) sham-operated (Sham); 2) ovariectomized (Ovx); and 3) ovariectomized chronically-treated with estrogen (Ovx+E2). Contractile responses to KCl (60mM) and thromboxane A(2) were greater in aorta from SAMP8 mice compared with SAMR1 in all groups. Neither ovariectomy nor estrogen replacement modified the contractile responses from SAMR1 mice. Conversely, in Ovx SAMP8 the increased maximal contract…
Modulatory Role of Endothelial and Nonendothelial Nitric Oxide in 5-Hydroxytryptamine-induced Contraction in Cerebral Arteries after Subarachnoid Hem…
1996
OBJECTIVE : Endothelial dysfunction is claimed to play a role in the pathogenesis of delayed cerebral vasospasm after subarachnoid hemorrhage (SAH). We have examined the effect of experimental SAH on the modulatory action of endothelial and nonendothelial nitric oxide (NO) in the contractile response of goat middle cerebral artery to 5-hydroxytryptamine (5-HT). METHODS : We compared the 5-HT-induced contractile responses of cerebral arteries from control goats and from goats with SAH that had been experimentally induced 3 days earlier by delivery of autologous arterial blood into the subarachnoid space. Contractile responses were examined by recording the isometric tension in isolated cereb…
Changes in the cerebrovascular effects of endothelin-1 and nicardipine after experimental subarachnoid hemorrhage.
1993
The role of endothelium-related factors in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage (SAH) has gained interest since the discovery of endothelin-1 (ET-1). We have examined, before and after SAH, the responsiveness of the cerebrovascular bed of the goat to ET-1, the sources of Ca2+ in ET-1-induced responses, and the ability of the Ca2+ entry blocker nicardipine to counteract them. Before SAH, injection of ET-1 into the cerebral circulation increased cerebrovascular resistance, thereby producing dose-dependent reductions in cerebral blood flow (CBF), which were prevented by nicardipine. In isolated middle cerebral arteries, ET-1 induced concentration-dependent contr…
Endothelin-1-Mediated Drug Resistance in EGFR-Mutant Non-Small Cell Lung Carcinoma.
2020
Abstract Progression on therapy in non-small cell lung carcinoma (NSCLC) is often evaluated radiographically, however, image-based evaluation of said therapies may not distinguish disease progression due to intrinsic tumor drug resistance or inefficient tumor penetration of the drugs. Here we report that the inhibition of mutated EGFR promotes the secretion of a potent vasoconstrictor, endothelin-1 (EDN1), which continues to increase as the cells become resistant with a mesenchymal phenotype. As EDN1 and its receptor (EDNR) is linked to cancer progression, EDNR-antagonists have been evaluated in several clinical trials with disappointing results. These trials were based on a hypothesis that…