Search results for "Constriction"
showing 10 items of 254 documents
Pre-clinical assessment of a water-in-fluorocarbon emulsion for the treatment of pulmonary vascular diseases
2019
Abstract Hypoxic pulmonary vasoconstriction (HPV) is a well-characterized vascular response to low oxygen pressures and is involved in life-threatening conditions such as high-altitude pulmonary edema (HAPE) and pulmonary arterial hypertension (PAH). While the efficacy of oral therapies can be affected by drug metabolism, or dose-limiting systemic toxicity, inhaled treatment via pressured metered dose inhalers (pMDI) may be an effective, nontoxic, practical alternative. We hypothesized that a stable water-in-perfluorooctyl bromide (PFOB) emulsion that provides solubility in common pMDI propellants, engineered for intrapulmonary delivery of pulmonary vasodilators, reverses HPV during acute h…
Vascular effects of sildenafil in patients with pulmonary fibrosis and pulmonary hypertension: an ex vivo/in vitro study
2015
Sildenafil improves the 6-min walking distance in patients with idiopathic pulmonary fibrosis (IPF) and right-sided ventricular systolic dysfunction.We analysed the previously unexplored role of sildenafil on vasoconstriction and remodelling of pulmonary arteries from patients with IPF and pulmonary hypertension (PH) ex vivo. Pulmonary arteries from 18 donors without lung disease, nine IPF, eight PH+IPF and four PH patients were isolated to measure vasodilator and anti-contractile effects of sildenafil in isometric organ bath. Ventilation/perfusion was explored in an animal model of bleomycin lung fibrosis.Sildenafil relaxed serotonin (5-HT) pre-contracted pulmonary arteries in healthy dono…
Bronchodilatory Effect of Deep Inspiration Is Absent in Subjects With Mild COPD
2004
Study objectives To investigate whether the bronchodilatory effect of deep inspiration is impaired in subjects with COPD. Methods We measured deep inspiration-induced bronchodilation in 19 patients with COPD and 17 healthy subjects (mean age, 67.8 ± 7.1 years vs 62.5 ± 9.3 years, respectively [± SEM]). Each subject underwent a series of single-dose methacholine provocations to induce at least a 15% reduction in inspiratory vital capacity (IVC). When this was achieved, subjects were asked to perform four consecutive deep inspirations, after which the IVC measurement was repeated and the percentage of bronchodilation by deep inspiration was calculated. Results The percentage of reduction in I…
Long-Term Follow-Up of Repeat Endoscopic Third Ventriculostomy in Obstructive Hydrocephalus.
2017
Endoscopic third ventriculostomy (ETV) is a safe and less-invasive treatment strategy for patients with obstructive hydrocephalus and provides excellent outcome. Nevertheless, repeat ETV in cases of ETV failure is a controversial issue.Between 1993 and 1999, 113 patients underwent a total of 126 ETVs at the Department of Neurosurgery, Mainz University Hospital. Obstructive hydrocephalus was the causative pathology in all cases. A very long-term follow-up of up to 16 years could be achieved. All medical reports of patients who received ETV were reviewed and analyzed with focus on ETV failure with following repeat ETV and its initial as well as very long-term success.Thirty-one events of ETV …
Diabetes-induced changes in endothelial mechanisms implicated in rabbit carotid arterial response to 5-hydroxytryptamine
2000
Abstract The influence of diabetes on endothelial mechanisms implicated in the response of isolated rabbit carotid arteries to 5-hydroxytryptamine (5- HT ) was studied. 5-HT induced a concentration–dependent contraction that was potentiated in arteries from diabetic rabbits with respect to that in arteries from control rabbits. Endothelium removal potentiated 5-HT contractions in arteries from both control and diabetic rabbits but increased the maximum effect only in arteries from diabetic rabbits. Incubation of arterial segments with N G -nitro- l -arginine ( l- NA) enhanced the contractile response to 5-HT. This l -NA enhancement was greater in arteries from diabetic rabbits than in arter…
Participation of Intracellular Calcium Stores in Serotonin-Induced Contractions in Rat Aorta
1993
Serotonin 1 mumol/l induces a contractile response in the isolated rat aorta in both the presence or absence of extracellular Ca. The present study analyzes the influence of temperature and caffeine on subsequent serotonin-induced contractions. In Ca-free medium, the contraction elicited by serotonin was higher at 25 degrees C than at 37 degrees C. In addition, the existence of two independent intracellular Ca pools releasable by serotonin, one of them also sensitive to caffeine, is postulated. The results also showed that addition of serotonin decreases the contractile response to this agonist in Ca-free medium.
Sialodochoplasty in the treatment of salivary-duct stricture in chronic sialoadenitis: technique and results
2007
PURPOSE: This study was undertaken to investigate peroral balloon angioplasty of salivary-duct strictures (sialodochoplasty) in chronic sialadenitis, analysing the technique, results and limitations. MATERIALS AND METHODS: Nine patients underwent sialodochoplasty: seven for Stensen''s-duct strictures and two for Wharton''s-duct strictures. One patient had a double stricture of Stensen''s duct and another a salivary stone associated with a Wharton''s-duct stricture. All patients were subjected to preliminary sialography to evaluate stricture site, length and grade. Sialodochoplasty was performed after local anaesthesia and progressive dilation of the salivary-duct orifice. RESULTS: The stric…
DOSE-RELATED EFFICACY OF A CONTINUOUS INTRACISTERNAL NIMODIPINE TREATMENT ON CEREBRAL VASOSPASM IN THE RAT DOUBLE SUBARACHNOID HEMORRHAGE MODEL
2009
Objective Intracisternal continuous therapy is a concept in the treatment of cerebral vasospasm after subarachnoid hemorrhage. The purpose of the current study was to investigate the effect of intracisternal nimodipine after induced vasospasm. Methods Sixty-five male Wistar rats were randomized into 4 groups: the control sham-operated group, the control subarachnoid hemorrhage-only group, and the treatment groups receiving 5 or 10 microL/hour of intracisternal nimodipine continuously for 5 days via subcutaneously implanted Alzet osmotic pumps (Durect Corp., Cupertino, CA). Vasospasm was analyzed 5 days later by means of digital subtraction angiography. Morphological examination of the brain…
Effectiveness of oral N -acetylcysteine in a rat experimental model of asthma
2002
Oxidative stress appears to be relevant to asthma pathogenesis. Therefore, the effectiveness of the antioxidant N -acetylcysteine was examined on antigen-induced pulmonary responses in sensitized Brown-Norway rats. N -acetylcysteine (oral, 1 mmol kg(-1)per day for 7 days before challenge) did not reduce the immediate bronchospasm that followed aerosol antigen exposure but prevented airway hyperreactivity to 5-hydroxytryptamine at 24 h after antigen challenge, and reduced the eosinophils (from 0.178 +/- 0.038 in the absence to 0.064 +/- 0.020 x10(6)cells ml(-1)in the presence of N -acetylcysteine;P< 0.05), and Evans blue dye extravasation in bronchoalveolar lavage fluid. Taurine levels in br…
Staphylococcal α-toxin provokes coronary vasoconstriction and loss in myocardial contractility in perfused rat hearts: Role of thromboxane generation
2000
Background —Cardiac performance is severely depressed in septic shock. Endotoxin has been implicated as the causative agent in Gram-negative sepsis, but similar abnormalities are encountered in Gram-positive sepsis. We investigated the influence of the major exotoxin of Staphylococcus aureus, staphylococcal α-toxin, in isolated perfused rat hearts. Methods and Results —α-Toxin 0.25 to 1 μg/mL caused a dose-dependent increase in coronary perfusion pressure that more than doubled. In parallel, we noted a decrease in left ventricular developed pressure and the maximum rate of left ventricular pressure rise (dP/dt max ), dropping to a minimum of <60% of control. These changes were accompani…