Search results for "Constriction"

Changes in Adrenoceptors and G-Protein-Coupled Receptor Kinase 2 in <smlcap>L</smlcap>-NAME-Induced Hypertension Compared to Spontaneous …

2014

This work compares the expression of adrenoceptors (ARs) and G-protein-coupled receptor kinase (GRK) 2 (RT-PCR and immunoblotting) and functional responses in conductance (aorta) and resistance vessels (mesenteric resistance arteries; MRA) in two different models of rat hypertension: hypertension induced by chronic treatment with <smlcap>L</smlcap>-NAME (N<sup>G</sup>-nitro-<smlcap>L</smlcap>-arginine methyl-ester) (<smlcap>L</smlcap>-NAME-treated rats; LNHR), and genetically induced hypertension (spontaneously hypertensive rats; SHR). Changes found in the aorta, but not in the MRA, were: (1) a loss of contractile capacity, more evidently in α…

Opposite vascular activity of (R)-apomorphine and its oxidised derivatives. Endothelium-dependent vasoconstriction induced by the auto-oxidation meta…

2003

We have synthetised a series of oxidised apomorphine derivatives (orto and para quinones 2-5), in order to analyse their vascular activity. We have performed radioligand binding assays on rat cortical membranes and functional studies on rat aortic rings. Instead the relaxant activity exhibited by (R)-apomorphine, o-quinones 2, 4, show contractile activity dependent on endothelium in rat aortic rings. Compound 2, the main metabolite of (R)-apomorphine auto-oxidation, was the product which showed enhanced contractile activity by a complex mechanism related to activation of Ca(2+) channels through release and/or inhibition of endothelial factors. Moreover, this compound disrupts the endothelia…

Minimal clinically important difference for asthma endpoints: an expert consensus report

2020

Minimal clinically important difference (MCID) can be defined as the smallest change or difference in an outcome measure that is perceived as beneficial and would lead to a change in the patient's medical management.The aim of the current expert consensus report is to provide a “state-of-the-art” review of the currently available literature evidence about MCID for end-points to monitor asthma control, in order to facilitate optimal disease management and identify unmet needs in the field to guide future research.A series of MCID cut-offs are currently available in literature and validated among populations of asthmatic patients, with most of the evidence focusing on outcomes as patient repo…

11,12-EET Stimulates the Association of BK Channel α and β1 Subunits in Mitochondria to Induce Pulmonary Vasoconstriction

2012

In the systemic circulation, 11,12-epoxyeicosatrienoic acid (11,12-EET) elicits nitric oxide (NO)- and prostacyclin-independent vascular relaxation, partially through the activation of large conductance Ca(2+)-activated potassium (BK) channels. However, in the lung 11,12-EET contributes to hypoxia-induced pulmonary vasoconstriction. Since pulmonary artery smooth muscle cells also express BK channels, we assessed the consequences of BKβ(1) subunit deletion on pulmonary responsiveness to 11,12-EET as well as to acute hypoxia. In buffer-perfused mouse lungs, hypoxia increased pulmonary artery pressure and this was significantly enhanced in the presence of NO synthase (NOS) and cyclooxygenase (…

Vascular Dysfunction in Experimental Diabetes Is Improved by Pentaerithrityl Tetranitrate but Not Isosorbide-5-Mononitrate Therapy

2011

OBJECTIVE Diabetes is associated with vascular oxidative stress, activation of NADPH oxidase, and uncoupling of nitric oxide (NO) synthase (endothelial NO synthase [eNOS]). Pentaerithrityl tetranitrate (PETN) is an organic nitrate with potent antioxidant properties via induction of heme oxygenase-1 (HO-1). We tested whether treatment with PETN improves vascular dysfunction in the setting of experimental diabetes. RESEARCH DESIGN AND METHODS After induction of hyperglycemia by streptozotocin (STZ) injection (60 mg/kg i.v.), PETN (15 mg/kg/day p.o.) or isosorbide-5-mononitrate (ISMN; 75 mg/kg/day p.o.) was fed to Wistar rats for 7 weeks. Oxidative stress was assessed by optical methods and o…

Progressive Development of Renal Vascular Dysfunction in Brain Death Implicates Reversible Alterations of Nitric Oxide Metabolism

2011

Vascular endothelial dysfunction occurs in the kidney graft from marginal brain death (BD) donors and may be responsible for a low success rate after transplantation.BD was induced in 16 dogs for 6 hours. Immediately after the inflation of the intracranial balloon, the treated group (n = 8) received 40 mg/kg bolus followed by 3 mg/kg/min infusion of L-arginine for 30 minutes. Renal vascular function and hemodynamic and biochemical parameters were determined.BD caused vasoconstriction, increase in renal venous nitrite (4.9 ± 0.8 versus 2.6 ± 0.1, P.05) and myeloperoxidase levels (1.43 ± 0.04 versus 2.43 ± 0.23, P.001), and reduced vasodilatation of renal artery to acetylcholine. Larginine di…

The interaction between circadian rhythms of endothelial function: resting versus recruitable endothelial function

2013

“The importance of being external”: review of the literature of the rare phenomenon of common carotid occlusion with bulb reverse-crossed stenosis an…

2022

Common carotid artery occlusion (CCAO) is a rare phenomenon associated with the development of neurological symptoms. In CCAO, diversion of blood flow from the external carotid artery (ECA) to the internal carotid artery (ICA) via the carotid bulb (CB) may occur. This pathway activation has been called "carotid steal". Starting from a particular case we describe the ECD finding of a complete occlusion of CCA with patency of ICA and ECA. In case of occlusion of CCA, inversion of the ECA flow may occur, towards the ICA, and it can be damped by a significant stenosis crossed in retrograde direction that may concur to maintain the pressure balance between the two circulations. Usually, this par…

Bispectral index changes in carotid surgery.

2010

Intraoperative monitoring of cerebral ischemia with shunting during carotid endarterectomy (CEA) remains controversial. Our objective was to evaluate the sensitivity and specificity of BIS changes during carotid clamping in relation to shunted patients in awake CEA.Eighty CEAs under cervical block were included. There were two patient groups: with clinical signs of cerebral ischemia (shunted patients) and without signs of cerebral ischemia (nonshunted patients). Data were based on bispectral index (BIS) values and neurological monitoring at different surgery time points, with special attention paid during carotid clamping. BIS values were compared between shunted and nonshunted patients. Se…

Delayed filling of retinal and ciliary circulation after central retinal artery occlusion

1988

The filling times of the retinal and choroidal circulation were evaluated in 17 patients with central retinal artery occlusion by means of fluorescein angiography. A correlation between the filling times of the two circulations was found. However, two filling patterns were seen: first, both fillings delayed; second, both fillings normal. It is probable that in the former case an obstructive disease of the carotid arteries exists, while in the latter case an important pathology of the carotid arteries is lacking, favouring a rapid restoration of the retinal circulation. This hypothesis seems to be confirmed by the results of the Doppler velocimetry of the carotid arteries.