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Luminal Diameter (luminal + diameter)
Selected AbstractsNitric oxide counteracts angiotensin II induced contraction in efferent arterioles in miceACTA PHYSIOLOGICA, Issue 4 2004A. Patzak Abstract Aim:, Efferent arterioles (Ef) are one of the final control elements in glomerular haemodynamics. The influence of nitric oxide (NO) on Ef remains ambiguous. Methods:, To test the hypothesis that endothelial NO plays an important role in this context, afferent arterioles (Af) and Ef of wild-type mice (WT), and Ef of mice lacking the endothelial NO synthetase [eNOS(,/,)] were perfused. Perfusion was performed in Ef via Af (orthograde) as well as from the distal end of Ef (retrograde), which provides an estimate for the importance of substances derived from the glomerulus. Angiotensin II (Ang II) was added in doses ranging from 10,12 to 10,6 mol L,1 to the bath solution. Results:, Ang II reduced the luminal diameter of Af to 68 ± 7 and in Ef to 55 ± 8% during orthograde, and to 35 ± 6% during retrograde perfusion (10,6 mol L,1 Ang II) in WT. Pre-treatment with NG -Nitro- l -arginine-methylester (l -NAME) (10,4 mol L,1) increased the Ang II sensitivity in retrograde (17 ± 9%) and orthograde perfused Ef (19 ± 9%). The Ang II sensitivity was enhanced in eNOS(,/,) mice compared with WT, too. Already at a dose of Ang II 10,9 mol L,1, luminal diameters diminished to 8 ± 7 and 7 ± 4%. Conclusion:, The increased Ang II sensitivity during l -NAME pre-treatment and in eNOS(,/,) mice indicates a strong counteraction of endothelial derived NO on Ang II induced contraction in Ef. Moreover, Ef are similarly sensitive to Ang II during either retrograde or orthograde perfusion in the absence of NO effects, suggesting that NO mediates, at least in part, the action of potential vasodilatory substances from the glomerulus. [source] Changes in capillary luminal diameter in rat soleus muscle after hind-limb suspensionACTA PHYSIOLOGICA, Issue 4 2000Kano This study examined the time course change of the capillary luminal diameter and the number of capillaries in the rat soleus muscle during hind-limb suspension. Male Wistar rats were divided into 1 and 3 weeks of hind-limb suspension (HS) groups (HS-1 and HS-3). The HS groups were compared with age-matched control groups. All morphometric parameters with respect to capillary and muscle fibre cross-sectional area were determined in perfusion-fixed soleus muscles. After 1 and 3 weeks of hind-limb suspension, the mean muscle fibre cross-sectional area was significantly decreased in HS-1 (,32.0%) and HS-3 (,59.3%) compared with age-matched control groups. Despite a lower capillary-to-fibre ratio (HS-1, ,19.3%; HS-3, ,21.2%), the capillary density was unchanged in HS-1 and significantly increased in HS-3 compared with age-matched control groups. The mean capillary luminal diameter was significantly smaller in HS-1 (,19.9%) and HS-3 (,21.9%) than in the age-matched control groups. The capillary-to-fibre perimeter ratio which indicates the capillary surface area available for gas exchange between blood and tissue did not significantly differ between control groups and HS groups. In conclusion, the morphometrical adaptations in rat soleus with the suspension involved changes in both the capillary luminal diameter and number of capillaries, and the change in capillary surface area was proportional to the degree of muscle atrophy in HS groups. [source] Is Left Ventricular Diastolic Thickening Documented During Dobutamine and Pacing Stress Echocardiography Related to Myocardial Ischemia?ECHOCARDIOGRAPHY, Issue 1 2002An Animal Model Study Transient increase in diastolic wall thickness (pseudohypertrophy) during pacing stress echocardiography has been reported in normal myocardium. To evaluate the occurrence of pseudohypertrophy and to investigate the contribution of myocardial ischemia on its production during pacing and dobutamine stress echocardiography, we produced a physiologically significant coronary stenosis in 14 open chest dogs. The stenosis in the circumflex artery was measured by quantitative coronary angiography (range: 50% to 89% reduction in luminal diameter), and no resting segmental wallmotion abnormalities were observed by epicardial echocardiography (short-axis, papillary level). In each study, dobutamine (5,40 ,g/kg/min) and pacing (up to 260 beats/min) were performed randomly. Positivity of stress echocardiography tests was quantitatively determined by a significant (P < 0.05) reduction or failure to increase in absolute and percent systolic wall thickening in the myocardial area supplied by the stenotic artery as compared to the left anterior descending (LAD) artery-related areas. Diastolic wall thickness and left ventricular diastolic area were compared before and after each stress test in the circumflex and LAD artery-related regions. Pseudohypertrophy was observed in 57% and 86% of dogs for pacing and dobutamine, respectively, in the circumflex region, and in 50% and 64% in the LAD region. Despite its increased incidence in the circumflex region, the augmented diastolic wall thickness did not correlate with coronary stenosis severity or stress test positivity, but correlated inversely with changes in left ventricular diastolic area. In addition, it correlated directly with changes in heart rate only for pacing. In conclusion, pseudohypertrophy was a frequent finding during pacing and dobutamine stress echocardiography tests but was not related to myocardial ischemia in this animal model. [source] Impact of Tricuspid Regurgitation and Prior Coronary Bypass Surgery on the Geometry of the Coronary Sinus: A Rotational Coronary Angiography StudyJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2010DAN BLENDEA M.D., Ph.D. Coronary Venous Geometry in Patients Undergoing CRT.,Introduction: The coronary sinus (CS) is often distorted in patients with advanced cardiomyopathy, making CS cannulation difficult. The objective of this study was to examine the impact of the underlying cardiac pathology on the variability of the CS anatomy, using rotational coronary venous angiography (RCVA). Methods and Results: Seventy-nine patients undergoing RCVA for cardiac resynchronization therapy (CRT) were evaluated: age 63 ± 15 years, 43% with prior coronary artery bypass grafting (CABG). Aspects of the CS anatomy which could impact cannulation were examined: the CS ostial angle, the posterior displacement of the CS away from the atrioventricular groove, a measure of CS curvature, and the presence of stenoses and aneurysmal dilatations. The CS ostial angle was variable (65,151°, mean 119 ± 19°, <90° in 8 patients) and decreased significantly (P = 0.0022) with increasing severity of tricuspid regurgitation (TR), reaching 94 ± 18° in patients with severe TR. The posterior displacement of the CS was significantly more accentuated in patients with prior CABG when compared with the patients without CABG (7.1 ± 3.7 vs 4.5 ± 2.8 mm; P = 0.0246). The decrease in luminal diameter at the CS,great cardiac vein (GCV) junction was 2.0 ± 1.0 mm, being more pronounced in patients with prior CABG versus nonCABG (26 vs 20%; P = 0.042). Stenoses and aneurysmal dilatations of the CS,GCV were encountered in 4 (5%) and 6 (8%) of patients, respectively, all of them with prior CABG, representing 12% and 18% of the CABG group. Conclusion: The CS anatomy in patients undergoing CRT is variable, and is impacted by the severity of the underlying TR and history of a prior CABG. (J Cardiovasc Electrophysiol, Vol. 21, pp. 436,440, April 2010) [source] Cutting Balloon for In-Stent Restenosis:JOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 4 2004Acute, Long-Term Results Introduction: Conventional percutaneous coronary intervention for the treatment of in-stent restenosis (ISR) has shown a high rate of ISR (30,55%). Considering the need for both extrusion of hyperplastic intima and additional stent expansion, a cutting balloon might be more effective for the treatment of ISR. Methods: We prospectively assessed the immediate and 8-month outcome of balloon angioplasty using the Barath Cutting Balloon in 100 consecutive patients (mean age: 60.5 ± 10.8 years, 71% male). Results: In 73 lesions (73%), a good result was reached with the cutting balloon only. In 21 lesions (21%) postdilatation and in 6 lesions (6%) predilatation with a conventional balloon was necessary. The mean inflation pressure was 8.7 ± 2.0 (range: 6.0,18.0) atm. Before the procedure the mean minimal luminal diameter (MLD) was 0.95 ± 0.45 mm. Quantitative coronary analysis showed a mean diameter stenosis of 65%± 16%. Immediately after the procedure the mean MLD was 2.42 ± 0.54 mm with a mean diameter stenosis of 19%± 13%. Two patients died during the follow-up period (1 stroke, 1 nonvascular). At 8-month follow-up 26 patients (26%) reported to have anginal complaints CCS class II,IV of whom 16 (16%) needed target lesion revascularization. Conclusion: Treatment of ISR using the Barath Cutting Balloon can be performed safely with good immediate results and a relatively low need for repeated target lesion revascularization at 8-month follow-up. [source] Reactive Oxygen Species Are Necessary for High Flow (Shear Stress)-induced Diameter Enlargement of Rat Resistance ArteriesMICROCIRCULATION, Issue 5 2009ERIC J. BELIN DE CHANTEMÈLE ABSTRACT Objectives: Chronic increases in blood flow induce remodeling associated with increases in diameter and endothelium-mediated dilation. Remodeling requires cell growth and migration, which may involve reactive oxygen species (ROS). Nevertheless, the role of ROS in flow-mediated remodeling in resistance arteries is not known. Materials and Methods: Rat mesenteric resistance arteries (MRAs) were exposed to high flow (HF) by sequentially ligating second-order MRAs in vivo. After three weeks, arteries were collected for structural, pharmacological, and biochemical analysis. Results: In HF arteries, luminal diameter (431±12 to 553±14 ,m; n=10), endothelium (acetylcholine)-mediated vasodilatation (61±6 to 77±6% relaxation) and NAD(P)H subunit (gp91phox and p67phox) expression levels, and ROS (dihydroethydine microphotography) and peroxynitrite (3-nitro-tyrosine) production were higher than in normal flow arteries. Acute ROS scavenging with tempol improved acetylcholine-dependent relaxation (92±4% relaxation), confirming that ROS are produced in HF arteries. Chronic treatment with tempol prevented the increase in diameter, reduced ROS and peroxynitrite production, and improved endothelium-mediated relaxation in HF arteries. Thus, ROS and NO were involved in HF-induced diameter enlargement, possibly through the formation of peroxynitrite, while ROS reduced the increase in endothelium-dependent relaxation. Conclusions: ROS production is necessary for flow-mediated diameter enlargement of resistance arteries. However, ROS counteract, in part, the associated improvement in endothelium-mediated relaxation. [source] Altered Autonomic Cardiac Control Predicts Restenosis After Percutaneous Coronary InterventionPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2 2006MATTHIAS GOERNIG Background: Early and late restenosis in up to 30% remains a major problem for long-term success after percutaneous coronary intervention (PCI). Compared to bare metal stents, the use of drug-eluting stents reduces restenosis below 10%, but implant coasts have to be considered. In restenosis noninvasive testing lacks diagnostic power. We applied a new approach to identify patients with a high risk for restenosis after PCI by combining heart rate (HR) and blood pressure variability (BPV) analyses. Methods: In 52 patients with clinical suspicion of restenosis and history of PCI, we investigated patterns of cardiovagal autonomic regulation prior to cardiac catheterization. The patients were separated in (i) patients with restenosis (CAD+R) and (ii) patients without restenosis (CAD,R), where restenosis is defined as a stenosis greater than 75% of luminal diameter in at least one main vessel. The following parameters/methods were evaluated: Canadian Cardiovascular Society grade (CCS-grade), vessel disease score (CAD-level), left ventricular ejection fraction (LVEF), heart rate variability (HRV), BPV, baroreflex sensitivity (BRS), as well as HR turbulence and blood pressure (BP) potentiation caused by premature ventricular complexes. Results: Whereas age, LVEF, CAD-level, CCS-grade, and mean BP did not differ between CAD+R and CAD,R, significant differences were found in (i) BPV: diastolic LF/P, systolic, and diastolic UVLF, (ii) in BRS: slope of tachycardic sequences, and (iii) in extrasystolic parameters: heart rate turbulence onset (HRTO) and potentiation of systolic BP (SBPP). Standard HRV parameters did not show significant differences between the groups. Using the two parameters diastolic LF/P (threshold >0.2) and HRTO (threshold >0) restenosis were predicted in 83.4%. Conclusions: These results demonstrate that indicators of sympathetic activation or vagal depression identify restenosis in patients after PCI, thus opening a perspective for a new noninvasive monitoring. [source] Pyogenic granuloma of the oral cavity: Comparative study of its clinicopathological and immunohistochemical featuresPATHOLOGY INTERNATIONAL, Issue 7 2005Apostolos Epivatianos There are two histological types of pyogenic granuloma (PG) of the oral cavity: the lobular capillary hemangioma (LCH) and non-LCH type. The aim of the present study was to examine and compare the clinical features, etiological factors, diameter of vascular elements and immunohistochemical features of LCH and non-LCH histological types of PG to determine whether they are two distinct entities. Thirty cases of LCH and 26 cases of non-LCH PG were retrieved and retrospectively studied. Clinically, LCH PG occurred more frequently (66.4%) as sessile lesion whereas non-LCH PG occurred as pedunculated (77%). Non-LCH PG was associated more frequently (86.4%) with etiological factors. The lobular area of the LCH PG contained a greater number of blood vessels with small luminal diameter than did the central area of non-LCH PG. In the central area of non-LCH PG a significantly greater number of vessels with perivascular mesenchymal cells non-reactive for ,-smooth muscle actin and muscle-specific actin was present than in the lobular area of LCH PG. The differences found in the present study suggest that the two histological types of PG represent distinct entities. [source] Quantitative coronary arteriography on digital flat-panel systemCATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 2 2004Paul L. Van Herck MD Abstract On images acquired with a digital flat-panel (DFP) detector, known for its better image quality, the performance of a validated quantitative coronary arteriography (QCA) software, CAASII (Cardiovascular Angiography Analysis System or CAAS), and a DFP-dedicated QCA algorithm (flat-panel analysis software or FPAS) was compared in a phantom and a patient study. On phantom, FPAS performed with higher accuracy the quantification of the smallest tubes and the calibration of an empty catheter. The overall accuracy and precision for the quantification procedure was better for FPAS (0.07 ± 0.04 mm) than for the CAAS (0.19 ± 0.06 mm; P = 0.03 and P < 0.01, respectively). In the patient study, the main difference between the two algorithms was found in the small diameters: CAAS almost always gave higher values than FPAS for the minimal luminal diameter (P < 0.001) and could only give values up to 70% for diameter stenosis. In conclusion, the FPAS can be considered more appropriate for assessing severe stenoses on digital flat-panel images. Catheter Cardiovasc Interv 2004;63:192,200. © 2004 Wiley-Liss, Inc. [source] Nitric oxide counteracts angiotensin II induced contraction in efferent arterioles in miceACTA PHYSIOLOGICA, Issue 4 2004A. Patzak Abstract Aim:, Efferent arterioles (Ef) are one of the final control elements in glomerular haemodynamics. The influence of nitric oxide (NO) on Ef remains ambiguous. Methods:, To test the hypothesis that endothelial NO plays an important role in this context, afferent arterioles (Af) and Ef of wild-type mice (WT), and Ef of mice lacking the endothelial NO synthetase [eNOS(,/,)] were perfused. Perfusion was performed in Ef via Af (orthograde) as well as from the distal end of Ef (retrograde), which provides an estimate for the importance of substances derived from the glomerulus. Angiotensin II (Ang II) was added in doses ranging from 10,12 to 10,6 mol L,1 to the bath solution. Results:, Ang II reduced the luminal diameter of Af to 68 ± 7 and in Ef to 55 ± 8% during orthograde, and to 35 ± 6% during retrograde perfusion (10,6 mol L,1 Ang II) in WT. Pre-treatment with NG -Nitro- l -arginine-methylester (l -NAME) (10,4 mol L,1) increased the Ang II sensitivity in retrograde (17 ± 9%) and orthograde perfused Ef (19 ± 9%). The Ang II sensitivity was enhanced in eNOS(,/,) mice compared with WT, too. Already at a dose of Ang II 10,9 mol L,1, luminal diameters diminished to 8 ± 7 and 7 ± 4%. Conclusion:, The increased Ang II sensitivity during l -NAME pre-treatment and in eNOS(,/,) mice indicates a strong counteraction of endothelial derived NO on Ang II induced contraction in Ef. Moreover, Ef are similarly sensitive to Ang II during either retrograde or orthograde perfusion in the absence of NO effects, suggesting that NO mediates, at least in part, the action of potential vasodilatory substances from the glomerulus. [source] Fibrosis and Stenosis of the Long Penetrating Cerebral Arteries: the Cause of the White Matter Pathology in Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and LeukoencephalopathyBRAIN PATHOLOGY, Issue 4 2004Qing Miao MSc In cerebral autosomal dominant arteriopathy with subcortical infarcts and leuco-encephalopathy (CADASIL) the vascular smooth muscle cells are destroyed and granular osmiophilic material is deposited followed by fibrosis of the arterial wall. To verify whether true stenosis of the fibrotic white matter arteries is a key pathogenic event in CADASIL, we analyzed the thickness of walls (expressed as sclerotic index) and luminal diameters of penetrating arterioles in both grey matter and white matter of four CADASIL patients due to the C475T (R133C) mutation in the Notch3 gene and in 9 age-matched controls. We also reconstructed 9 arterioles from 1000 serial sections in two CADASIL patients. The thickness of the arteriolar walls in both grey matter and white matter was significantly increased in the CADASIL patients compared with controls. Furthermore, in CADASIL patients the arteriolar walls were significantly thicker in the white matter than in the grey matter. The distribution curve of arteriolar internal diameters in CADASIL patients shifted towards smaller sizes. In serial sections, the marked increase in the thickness of the white matter penetrating arterioles or their branches did not occur until the internal diameters had decreased to about 20 to 30 ,m and external diameters to about 100 to 130 ,m. In conclusion, long penetrating arterioles and their branches supplying subcortical structures in CADASIL are stenosed and their walls are thickened. This conforms to the abundance of infarcts and primary ischemic damage in CADASIL patients' white matter. [source] | ||||||||||||||||||||||