Search results for "Constriction"
showing 10 items of 254 documents
Endothelium-dependent responses in human isolated thyroid arteries from donors
2004
The functional properties of the endothelium of human thyroid arteries remain unexplored. We investigated the intervention of nitric oxide (NO), prostacyclin (PGI(2)) and endothelium-derived hyperpolarizing factor (EDHF) in the responses to acetylcholine and noradrenaline in isolated thyroid arteries obtained from multi-organ donors. Artery rings were suspended in organ baths for isometric recording of tension. The contribution of NO, PGI(2) and EDHF to endothelium-dependent relaxation was determined by the inhibitory effects of N(G)-monomethyl-L-arginine (L-NMMA), indomethacin, and K(+) channel inhibitors respectively. Acetylcholine induced concentration-dependent relaxation; this effect w…
The intravascular ultrasound morphometry of iliac veins in subjects without severe chronic venous insufficiency and its implications for treatment in…
2019
Objectives The purpose of this study is to report the intravascular ultrasound morphometry of iliac veins and its relation to demographic and anthropometric factors in subjects without chronic venous insufficiency. Methods Thirty-three patients, without chronic venous insufficiency – qualified to great saphenous vein stripping due to unilateral, primary varicose veins – participated in the study. During the surgery, left and right external iliac veins, common iliac veins and inferior vena cava were interrogated with intravascular ultrasound. The morphometric analysis included measurement of a cross-sectional area at normal, non-stenosed vein segments (ref-CSA) and at the point of the most p…
A multicenter, site-independent, blinded study to compare the diagnostic accuracy of contrast-enhanced magnetic resonance angiography using 1.0M gado…
2007
Abstract Purpose Prospective evaluation of diagnostic accuracy of single field-of-view contrast-enhanced MR Angiography (ceMRA) with 1.0 M gadobutrol compared to intraarterial DSA in body arteries. Materials and methods In an European multicenter study 179 patients underwent ceMRA and DSA. For each indication five prospectively defined vessel segments were evaluated by local investigators onsite and by three site-independent blinded readers (BR) independently. Results The agreement between ceMRA and DSA diagnosis was statistically significant in the onsite (96.6%) and blinded reader (86.6–90.2%) evaluation. Sensitivity, specificity, accuracy, positive (PPV) and negative predictive values (N…
Detection of coronary artery calcifications predicting coronary heart disease: comparison of fluoroscopy and spiral CT.
1998
The aim of this study was to evaluate the clinical relevance of coronary artery calcifications detected by spiral CT, congruence with fluoroscopy (FS) and coronary angiography, and comparison with studies reporting on application of double-helical CT and ultrafast CT. Forty patients underwent spiral CT (2-mm slice thickness, table feed 3 mm/s), coronary angiography, and FS (performed in the usual manner). Stenosis and calcifications were evaluated semiquantitatively. Nineteen patients suffering from a stenosis ≥ 75 % were verified at coronary angiography. All had coronary artery calcification on spiral CT. Fluoroscopy did not detect 8 of 19 patients with a stenosis ≥ 75 % (1 vessel: n = 1; …
Plasma endothelin-1 levels in patients with angina pectoris and normal coronary angiograms.
1998
Some patients with typical angina and electrocardiographic evidence of ischemia have normal coronary angiograms. These patients have a reduced coronary flow reserve and abnormal endothelium-dependent vasodilator responses; this syndrome is known as microvascular angina. Among endothelium-derived peptides, endothelin-1 (ET-1) is a potent vasoconstrictor and an important modulator of microvascular function.Plasma ET-1 was measured in 13 patients with typical angina, instrumental evidence of ischemia, and normal arteriograms and in 20 normal control subjects.Mean concentration of ET-1 was 2.89+/-1.24 pmol/L in patients with angina and normal angiograms and 1.99+/-0.81 pmol/L in normal control …
Is ERCP manometry useful in the choice of treatment of stones of the common bile duct?
1988
To verify the appropriateness of sphincterotomy as the treatment of choice of choledocholithiasis, since 1980 we have been using endoscopic retrograde cholangiopancreatographic (ERCP) manometry of the sphincter of Oddi (SO). This method allows direct investigation of SO motor activity and provides useful information regarding the presence of benign papillary stenosis (BPS). Thirty-four patients were investigated because the radiological examination indicated BPS might be present. Of these, 20 had common bile duct (CBD) stones, while the remaining 14 presented with biliarylike pain and one or more of the following: CBD dilation (larger than 12 mm); emptying of the ERCP contrast medium took l…
Fibrinolysis in hypertriglyceridaemic subjects in response to venous occlusion.
1993
We have measured various fibrinolytic and coagulation parameters (t-PA antigen, PAI, fibrinogen, plasminogen and factor VII) before and after 10 min of venous occlusion in 20 hypertryglyceridaemic subjects (twelve males and eight females, age 38 +/- 4 years, body mass index 23 +/- 1.5) and 20 healthy normal subjects, matched for sex (twelve males and eight females), age (37 +/- 3.5 years) and body mass index (22.8 +/- 1.4). At rest, t-PA:Ag, PAI, fibrinogen, plasminogen and factor VII were significantly (P < 0.005) higher in hypertriglyceridaemic subjects than in normal controls. After venous occlusion, the increase in all parameters except t-PA:Ag was more marked in the patient group than …
Influence of Endothelial Nitric Oxide on Adrenergic Contractile Responses of Human Cerebral Arteries
1996
The present study was designed to investigate the influence of the endothelium and that of the L-arginine pathway on the contractile responses of isolated human cerebral arteries to electrical field stimulation (EFS) and norepinephrine. Rings of human middle cerebral artery were obtained during autopsy of 19 patients who had died 3–8 h before. EFS (1–8 Hz) induced frequency-dependent contractions that were abolished by tetrodotoxin, prazosin, and guanethidine (all at 10-6 M). The increases in tension were of greater magnitude in arteries denuded of endothelium. NG-monomethyl L-arginine (L-NMMA 10-4 M) potentiated the contractile response to EFS in artery rings with endothelium but did not …
Clonidine induces nitric oxide- and prostaglandin-mediated vasodilation in healthy human skin
2005
Sustained sympathetic activation not only leads to vasoconstriction but also might induce paradox vasodilation. This study was performed to explore whether and how alpha(2)-receptor stimulation mediates this vasodilation. We investigated 11 healthy subjects in 33 dermal microdialysis (MD) sessions. After nerve trunk blockade, MD fibers were inserted and perfused with physiological saline until skin trauma-related vasodilation subsided. Thereafter, fibers were perfused with either clonidine solutions (10(-3), 5 x 10(-4), 10(-4) mol/l), N(G)-monomethyl-l-arginine (L-NMMA; nitric oxide synthase blocker), acetylsalicylic acid (ASA; cyclooxygenase blocker), or combinations of these. Laser-Dopple…
Transposition of the left renal vein for treatment of the nutcracker phenomenon: long-term follow-up
2002
Abstract Objectives To assess the therapeutic value of left renal vein transposition for treatment of the nutcracker phenomenon in long-term follow-up. Methods Eight patients (4 women and 4 men) between 23 and 58 years old (mean 39.1) underwent transposition of the left renal vein for treatment of the nutcracker phenomenon associated with recurrent gross hematuria and flank pain. The postoperative follow-up was 41 to 136 months (mean 66.4). Results No perioperative complications were encountered. The postoperative complications comprised deep vein thrombosis (n = 1), retroperitoneal hematoma necessitating surgical revision (n = 1), and paralytic ileus that resolved with conservative managem…