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Diameter Changes (diameter + change)
Selected AbstractsC-Reactive Protein and Aortic Stiffness in Patients with Idiopathic Dilated CardiomyopathyECHOCARDIOGRAPHY, Issue 1 2007Feridun Kosar M.D. Background: Previous studies have shown an association between C-reactive protein (CRP)and arterial stiffness in most cardiovascular diseases. Increased CRP levels and arterial stiffness have been considered independent predictors of cardiovascular mortality in cardiovascular disease and even in the general population. Objective: The aim of this study was to investigate the relationship between CRP, a marker of systemic inflammation and aortic stiffness in patients with idiopathic dilated cardiomyopathy (DCMP). Methods: Serum CRP levels and aortic stiffness parameters were measured in DCMP patients (n= 37) and age- and gender-matched control subjects (n= 30). High-sensitivity CRP levels were determined by an immunonephelometry assay. Aortic strain (AS) and aortic distensibility (AD) were calculated from the aortic diameters measured using M-mode echocardiography and blood pressure obtained by sphygmomanometry. Results: Serum levels of CRP in DCMP patients were higher than in the control subjects (5.47 ± 2.06 mg/L and 2.35 ± 0.47 mg/L, P < 0.001, respectively). AS and AD were significantly decreased in DCMP patients compared to the controls (P < 0.001 and P < 0.001, respectively). There were positive correlations between CRP, and (r = 0.3.64, P = 0.027) smoking (r = 0.3.56, P = 0.024), and increasing age (r = 0.587, P < 0.001), and negative correlations between CRP, and DBP (r =,0.485, P < 0.001), diameter change (DC; r =,0.493, P < 0.001), AS (r =,0.526, P < 0.001), and AD (r =,0.626, P < 0.001). Conclusion: We have shown that there is a significant relation between high serum CRP levels and impaired aortic stiffness in patients with idiopathic DCMP. These findings may indicate an important role of CRP in the pathogenesis of impaired aortic stiffness in idiopathic DCMP. [source] Assessment of Carotid Compliance Using Real Time Vascular Ultrasound Image Analysis in Marfan SyndromeECHOCARDIOGRAPHY, Issue 4 2009Anatoli Kiotsekoglou M.D. Background: Fibrillin-1 deficiency, dysregulated cytokine transforming growth factor-,, and increased collagen deposition related to fibrillin-1 gene mutations could predispose to impaired carotid compliance (CC) in Marfan syndrome (MFS). We sought to detect any alterations in CC using the vascular image analysis system (VIA). Methods and Results: Thirty-two MFS patients, 20 men and 12 women (mean age 34.2 ± 12.05 years), and 29 controls matched for age, sex, and body surface area (BSA) were recruited. The entire length of each carotid system was initially scanned longitudinally using a 14 MHz linear transducer. Then, a stereotactic clamp held the transducer in contact with the carotid artery. Arterial diameter changes during the cardiac cycle were recorded for 1 minute from both right (RCCA) and left common carotid arteries (LCCA) separately using the VIA system. RCCA and LCCA compliance and distensibility measurements were significantly reduced in MFS patients when compared to controls, P < 0.05. RCCA and LCCA intima-media thickness did not differ between patients and controls, P > 0.05. MFS diagnosis and age were associated with reduced CC in both carotid arteries after adjusting for variables such as, sex, BSA, heart rate, beta-blockade, intima-media thickness, and aortic root size. Conclusions: Our findings showed a reduction in CC in adult patients with MFS. This could be attributed to fibrillin-1 deficiency resulting in structural abnormalities in the carotid arterial wall. [source] Below-ground hydraulic conductance is a function of environmental conditions and tree size in Scots pineFUNCTIONAL ECOLOGY, Issue 6 2007J. MARTÍNEZ-VILALTA Summary 1Variations in water tension in a transpiring tree cause elastic changes in stem diameter. To better understand the dynamics of these variations, stem diameter changes and sap flow rates were monitored simultaneously in trees from two Scots pine chronosequences in Scotland. 2Tree below-ground hydraulic conductance (kbg) was estimated from the relationship between leaf-specific sap flow rates and the difference between stem and soil water potentials estimated from diameter variations in the stem. 3In a given tree, kbg varied both within and among days, with conductance increasing as a function of sap flow and evaporative demand. These patterns could be explained in terms of a composite model of root water transport and possible changes in the gating of aquaporins. 4We interpreted these trends of increasing kbg with evaporative demand as a mechanism to enhance the ability of trees to control leaf water potential and keep it within physiologically acceptable limits, with potential implications for our general understanding of plant water relations, and for the estimation and modelling of ecosystem water fluxes. 5Across trees, kbg declined with increasing tree age/size, but the proportional contribution of below-ground to whole-tree hydraulic resistance also declined. This is consistent with an increase in below-ground carbon allocation in old/tall trees and a partial acclimation of tall trees to hydraulic limitations. It is argued that these trends have to be considered when discussing the importance of tree height for water transport and growth. [source] Motor patterns and propulsion in the rat intestine in vivo recorded by spatio-temporal mapsNEUROGASTROENTEROLOGY & MOTILITY, Issue 5 2005D. M. Ferens Abstract, We have used spatio-temporal maps derived from video images to investigate propagated contractions of the rat small intestine in vivo. The abdomen, including an exteriorized segment of jejunum, was housed in a humid chamber with a viewing window. Video records were converted to spatio-temporal maps of jejunal diameter changes. Intraluminal pressure and fluid outflow were measured. Contractions occupied 3.8 ± 0.2 cm of intestine and propagated anally at 3.1 ± 0.2 mm s,1 when baseline pressure was 4 mmHg. Contractions at any one point lasted 8.7 ± 0.6 s. Contractions often occurred in clusters; within cluster frequencies were 2.28 ± 0.04 min,1. Pressure waves, with amplitudes greater than about 9 mmHg, expelled fluid when the baseline pressure was 4 mmHg. In the presence ofl -NAME, circular muscle contractions occurred at a high frequency, but they were not propagated. We conclude that video recording methods give good spatio-temporal resolution of intestinal movement when applied in vivo. They reveal neurally-mediated propulsive contractions, similar to those previously recorded from intestinal segments in vitro. The propagated contractions had speeds of propagation that were slower and frequencies of occurrence that were less than speeds and frequencies of slow waves in the rat small intestine. [source] The effect of treatment zone diameter in hyperopic orthokeratologyOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 6 2009Paul Gifford Abstract Purpose:, To investigate the time course of treatment zone (TZ) diameter changes in hyperopic orthokeratology (OK) lens wear from 1 h in the open eye through to seven nights in the closed eye. Methods:, Twelve subjects were fitted with rigid hyperopic OK lenses. Lenses were worn in the open eye for 1 h then one night in the closed eye, separated by a washout period of 4 days. Changes in best corrected visual acuity (BCVA) and corneal topography (Medmont E-300) were measured on lens removal. The TZ, comprising the central steepened zone (CSZ) and surrounding annular flattened zone (AFZ), was measured from corneal topography. Subsequently, ten subjects wore the same lens design overnight for seven nights, and measurements were taken on lens removal and 8 h later on Days 1 and 7. Results:, Both CSZ and AFZ were apparent after 1 h of hyperopic OK lens wear. CSZ decreased while AFZ increased with longer periods of lens wear. BCVA reduced with longer periods of lens wear and was associated with decreasing CSZ (r = ,0.866, p < 0.001) and increasing AFZ (r = 0.447, p < 0.05). Conclusions:, The association of changes of treatment zone size with reductions in BCVA suggests that increasing CSZ may lead to better visual outcomes in hyperopic OK. [source] Effect of melt annealing on the phase structure and rheological behavior of propylene,ethylene copolymersPOLYMER ENGINEERING & SCIENCE, Issue 6 2007Vanesa De La Torre The morphological and rheological properties of a commercial propylene-ethylene copolymer (PEC) and a series of blends with different concentrations of poly (ethylene- co -propylene) are investigated. The blends are prepared mixing PEC with fractions obtained from it by solvent extraction. The phase structure of samples exposed to different thermal and mechanical histories was analyzed using scanning electron microscopy. The linear viscoelastic properties of the molten polymers were measured using different test sequences that include dynamic frequency and time sweeps. The phase structure of most blends changes dramatically with time when the polymers are kept in the molten state due to the coalescence of the domains. For example, the initial morphology of PEC which presents domains of ,1 ,m diameter changes to regions of more than 10 ,m of average diameter after 90 min at 178°C at rest. Coincidentally, the dynamic moduli of the blends change during annealing reaching values that depend on the mechanical history. For example, the elastic modulus of PEC increases ,32% during a dynamic time sweep of 45 min using a frequency of 0.1 s,1, while it decreases ,18% when a frequency of 1 s,1 is applied. Moreover, the modulus measured at 0.1 s,1 of samples annealed at rest during 45 min is ,58% larger than that of the fresh material. POLYM. ENG. SCI., 47:912,921, 2007. © 2007 Society of Plastics Engineers [source] | ||||||||||