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Artery Blood Flow (artery + blood_flow)
Kinds of Artery Blood Flow Terms modified by Artery Blood Flow Selected AbstractsCocaine and Ethanol: Combined Effects on Coronary Artery Blood Flow and Myocardial Function in DogsACADEMIC EMERGENCY MEDICINE, Issue 7 2009Lance D. Wilson MD Abstract Objectives:, In combination, cocaine and ethanol are more cardiotoxic than is either substance alone. These substances together constitute a drug abuse combination that commonly results in fatality. Previously the authors have demonstrated that cardiotoxicity of cocaine and ethanol is in part due to synergistic myocardial-depressant effects. However, it remains unclear whether this myocardial depression is associated with concomitant adverse effects on coronary blood flow in relation to these substances. The aim of this study was to investigate combined effects of cocaine and ethanol on myocardial blood flow, in relation to indices of myocardial function. Methods:, Anesthetized dogs were instrumented for hemodynamic monitoring with Doppler flow probes placed on the circumflex and left anterior descending (LAD) coronary arteries. Dogs were randomized to three groups (each n = 6): ethanol (E, 1.5 g/kg followed by placebo), cocaine (C, placebo followed by cocaine, 7.5 mg/kg IV), or cocaine plus ethanol (C + E). All measurements were made at control, after placebo or ethanol, and then at fixed time intervals after cocaine or placebo bolus over 3 hours. Results:, In both the C + E and the C groups, circumflex blood flow (CBF) decreased by 71% (95% confidence interval [CI] = 56% to 85%) and 57% (95% CI = 43% to 72%, both p < 0.04 vs. baseline) immediately after cocaine bolus. This was associated with transient depression of cardiac output, myocardial contractile function, and rate-pressure product (RPP), all indices of myocardial oxygen demand. A subsequent rebound increase of coronary sinus blood flow (CSBF) of 56% (95% CI = 26% to 137%, p < 0.03) compared to baseline occurred only in the C group and was associated with increases of myocardial contractile function and RPP. In the C + E group, 2 hours after drug administration, there was a decrease in CSBF of 49% (95% CI = 32% to 67%; p < 0.01) compared to baseline, which was associated with concomitant numerical decreases of the indices of myocardial oxygen demand and accumulation of cocaethylene. Conclusions:, Acute decreases in myocardial flow secondary to cocaine, and cocaine and ethanol in combination, were similar and temporally associated with cocaine's direct myocardial-depressant effects. Rebound increases in myocardial function and blood flow due to cocaine were attenuated by ethanol. Delayed myocardial depression and decreases in myocardial blood flow were observed only with coadministration of cocaine and ethanol. [source] Circulatory effects of apnoea in elite breath-hold diversACTA PHYSIOLOGICA, Issue 1 2009F. Joulia Abstract Aim:, Voluntary apnoea induces several physiological adaptations, including bradycardia, arterial hypertension and redistribution of regional blood flows. Elite breath-hold divers (BHDs) are able to maintain very long apnoea, inducing severe hypoxaemia without brain injury or black-out. It has thus been hypothesized that they develop protection mechanisms against hypoxia, as well as a decrease in overall oxygen uptake. Methods:, To test this hypothesis, the apnoea response was studied in BHDs and non-divers (NDs) during static and dynamic apnoeas (SA, DA). Heart rate, arterial oxygen saturation (SaO2), and popliteal artery blood flow were recorded to investigate the oxygen-conserving effect of apnoea response, and the internal carotid artery blood flow was used to examine the mechanisms of cerebral protection. Results:, The bradycardia and peripheral vasoconstriction were accentuated in BHDs compared with NDs (P < 0.01), in association with a smaller SaO2 decrease (,2.7% vs. ,4.9% during SA, P < 0.01 and ,6% vs. ,11.3% during DA, P < 0.01). Greater increase in carotid artery blood flow was also measured during apnoea in BHDs than in controls. Conclusion:, These results confirm that elite divers present a potentiation of the well-known apnoea response in both SA and DA conditions. This response is associated with higher brain perfusion which may partly explain the high levels of world apnoea records. [source] Effects of C-peptide on forearm blood flow and brachial artery dilatation in patients with type 1 diabetes mellitusACTA PHYSIOLOGICA, Issue 3 2001E. Fernqvist-Forbes Recent studies suggest that C-peptide increases blood flow in both exercising and resting forearm in patients with type 1 diabetes. Now we have studied the effect of C-peptide administration on endothelial-mediated and non-endothelial-mediated arterial responses as well as central haemodynamics in 10 patients with type 1 diabetes in a placebo-controlled double-blind study. Euglycaemia was maintained with an i.v. insulin infusion before and during the study. A high-resolution ultrasound technique and Doppler echocardiography were used to assess haemodynamic functions. Brachial artery blood flow and brachial artery diameter were measured in the basal state, 1 and 10 min after reactive hyperaemia and 4 min after sublingual glyceryl trinitrate administration (GTN; endothelial-independent vasodilatation), both before and after the end of 60-min C-peptide (6 pmol kg,1 min,1) or saline infusion periods. Echocardiographic measurements were also performed before and at the end of the infusion periods. Seven healthy age-matched males served as controls for vascular studies. The patients showed a blunted brachial dilatation after reactive hyperaemia in comparison with the healthy controls (2.1 ± 0.5% vs. 9.3 ± 0.3%, P < 0.001), indicating a disturbed endothelial function. C-peptide infusion compared with saline resulted in increased basal blood flow (33 ± 6%, P < 0.001) and brachial arterial dilatation (4 ± 1%, P < 0.05). Left ventricular ejection fraction seemed to be improved (5 ± 2%, P < 0.05) at the end of C-peptide infusion compared with placebo. The vascular response to reactive hyperaemia and GTN was not affected by C-peptide infusion. Our results demonstrate that physiological concentrations of C-peptide increase resting forearm blood flow, brachial artery diameter and left ventricular systolic function in patients with type 1 diabetes. [source] Reversal of portal hypertension and hyperdynamic splanchnic circulation by combined vascular endothelial growth factor and platelet-derived growth factor blockade in rats,HEPATOLOGY, Issue 4 2007Mercedes Fernandez Vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) pathways are crucial to angiogenesis, a process that contributes significantly to the pathogenesis of portal hypertension. This study determined the effects of inhibition of VEGF and/or PDGF signaling on hyperdynamic splanchnic circulation and portosystemic collateralization in rats with completely established portal hypertension, thus mimicking the situation in patients. Portal vein,ligated rats were treated with rapamycin (VEGF signaling inhibitor), Gleevec (PDGF signaling inhibitor), or both simultaneously when portal hypertension was already fully developed. Hemodynamic studies were performed by transit-time flowmetry. The extent of portosystemic collaterals was measured by radioactive microspheres. The expression of angiogenesis mediators was determined by Western blotting and immunohistochemistry. Combined inhibition of VEGF and PDGF signaling significantly reduced splanchnic neovascularization (i.e., CD31 and VEGFR-2 expression) and pericyte coverage of neovessels (that is, ,-smooth muscle actin and PDGFR-, expression) and translated into hemodynamic effects as marked as a 40% decrease in portal pressure, a 30% decrease in superior mesenteric artery blood flow, and a 63% increase in superior mesenteric artery resistance, yielding a significant reversal of the hemodynamic changes provoked by portal hypertension in rats. Portosystemic collateralization was reduced as well. Conclusions: Our results provide new insights into how angiogenesis regulates portal hypertension by demonstrating that the maintenance of increased portal pressure, hyperkinetic circulation, splanchnic neovascularization, and portosystemic collateralization is regulated by VEGF and PDGF in portal hypertensive rats. Importantly, these findings also suggest that an extended antiangiogenic strategy (that is, targeting VEGF/endothelium and PDGF/pericytes) may be a novel approach to the treatment of portal hypertension. (HEPATOLOGY 2007.) [source] Intraoperative portal vein blood flow predicts allograft and patient survival following liver transplantationHPB, Issue 3 2010Austin L. Spitzer Abstract Background:, We hypothesized that operative variables might predict survival following liver transplantation. Methods:, We examined perioperative variables from 469 liver transplants carried out at the University of Washington during 2003,2006. Logistic regression determined the variables' contributions to survival at 30, 90 and 365 days. Results:, Portal vein blood flow (>1 l/min) was significant to patient survival at 30, 90 and 365 days. Complete reperfusion was only a significant predictor of survival at 30 days. This provided model receiver operating characteristic (ROC) area under the curve (AUC) statistics of 0.93 and 0.87 for 30 and 90 days, respectively. At 365 days, hepatic artery blood flow (>250 ml/min) combined with portal vein blood flow was significantly predictive of survival, with an AUC of 0.74. A subset analysis of 110 transplants demonstrated improved 1-year survival with more aggressive vascular revisions. Discussion:, Portal vein blood flow is a significant predictor of survival after liver transplantation. Initially, the liver's survival is based on portal vein blood flow; however, subsequent biliary problems and patient demise result from both poor portal vein and inadequate hepatic artery blood flow. [source] Color doppler sonographic analysis of uterine and ovarian artery blood flow in women with polycystic ovary syndromeJOURNAL OF CLINICAL ULTRASOUND, Issue 6 2007Sebiha Özkan MD Abstract Purpose. To study the blood flow patterns of utero-ovarian circulation in polycystic ovary syndrome (PCOS) and to assess their relationship with clinical, metabolic, and hormonal data. Methods. Forty-three women with PCOS and 43 age-matched healthy controls underwent Doppler examination of the utero-ovarian circulation in the follicular phase. Demographic, hormonal, and metabolic parameters were determined. Student's t -test, ,2 -test, and Spearman correlation test were used for statistical analysis. Results. The ovarian artery pulsatility index (PI), resistance index (RI), and SD ratios were significantly lower in PCOS than in controls on the right side (p < 0.001, p = 0.02, p = 0.001, respectively) as well as on the left side (p < 0.001, p < 0.001, p < 0.001, respectively). The uterine artery systolic/diastolic (S/D) ratio was higher on both sides (p = 0.01) and the PI was higher on the left side (p = 0.02) in PCOS than in controls. The right uterine artery PI was positively correlated with luteinizing hormone and hemoglobin (r = 0.417, p = 0.043; r = 0.427, p = 0.033, respectively), the right uterine artery S/D was positively correlated with body mass index (r = 0.479, p = 0.015), and the left uterine artery PI was positively correlated with insulin (r = 0.458, p = 0.021). Conclusion. Doppler sonography of the utero-ovarian circulation may contribute to the evaluation of PCOS patients and a better understanding of the pathophysiology of this syndrome. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2007 [source] Tezosentan normalizes hepatomesenteric perfusion in a porcine model of cardiac tamponadeACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 2 2009A. ĹNEMAN Background: To investigate endothelin-1 (ET-1)-dependent hepatic and mesenteric vasoconstriction, and oxygen and lactate fluxes in an acute, fixed low cardiac output (CO) state. Methods: Sixteen anesthetized, mechanically ventilated pigs were studied. Cardiac tamponade was established to reduce portal venous blood flow (QPV) to 2/3 of the baseline value. CO, hepatic artery blood flow (QHA), QPV, hepatic laser-Doppler flow (LDF), hepatic venous and portal pressure, and hepatic and mesenteric oxygen and lactate fluxes were measured. Hepatic arterial (RHA), portal (RHP) and mesenteric (Rmes) vascular resistances were calculated. The combined ETA,ETB receptor antagonist tezosentan (RO 61-0612) or normal saline vehicle was infused in the low CO state. Measurements were made at baseline, after 30, 60, 90 min of tamponade, and 30, 60, 90 min following the infusion of tesozentan at 1 mg/kg/h. Results: Tamponade decreased CO, QPV, QHA, LDF, hepatic and mesenteric oxygen delivery, while hepatic and mesenteric oxygen extraction and lactate release increased. RHA, RHP and Rmes all increased. Ninety minutes after tesozentan, QPV, LDF and hepatic and mesenteric oxygen delivery and extraction increased approaching baseline values, but no effect was seen on CO or QHA. Hepatic and mesenteric handling of lactate converted to extraction. RHA, RHP and Rmes returned to baseline values. No changes were observed in these variables among control animals not receiving tesozentan. Conclusion: In a porcine model of acute splanchnic hypoperfusion, unselective ET-1 blockade restored hepatomesenteric perfusion and reversed lactate metabolism. These observations might be relevant when considering liver protection in low CO states. [source] Different vasodilator responses of human arms and legsTHE JOURNAL OF PHYSIOLOGY, Issue 3 2004Sean C. Newcomer Forearm vascular responses to intra-arterial infusions of endothelium-dependent and -independent vasodilators have been thoroughly characterized in humans. While the forearm is a well-established experimental model for studying human vascular function, it is of limited consequence to systemic cardiovascular control owing to its small muscle mass and blood flow requirements. In the present study we determined whether these responses could be generalized to the leg. Based upon blood pressure differences between the leg and arm during upright posture, we hypothesized that the responsiveness to endothelium-dependent vasodilators would be greater in the forearm than the leg. Brachial and femoral artery blood flow (Q, ultrasound Doppler) at rest and during intra-arterial infusions of endothelium-dependent (acetylcholine and substance P) and -independent (sodium nitroprusside) vasodilators were measured in eight healthy men (22,27 years old). Resting blood flows in the forearm before infusion of acetylcholine, substance P or sodium nitroprusside were 25 ± 4, 30 ± 7 and 29 ± 5 ml min,1, respectively, and in the leg were 370 ± 32, 409 ± 62 and 330 ± 30 ml min,1, respectively. At the highest infusion rate of acetylcholine (16 ,g (100 ml tissue),1 min,1) there was a greater (P < 0.05) increase in Q to the forearm (1864 ± 476%) than to the leg (569 ± 86%). Similarly, at the highest infusion rate of substance P (125 pg (100 ml tissue),1 min,1) there was a greater (P < 0.05) increase in Q to the forearm (911 ± 286%) than to the leg (243 ± 58%). The responses to sodium nitroprusside (1 ,g (100 ml tissue),1 min,1) were also greater (P < 0.05) in the forearm (925 ± 164%) than in the leg (326 ± 65%). These data indicate that vascular responses to both endothelium-dependent and -independent vasodilator agents are blunted in the leg compared to the forearm. [source] Reductions in basal limb blood flow and vascular conductance with human ageing: role for augmented ,-adrenergic vasoconstrictionTHE JOURNAL OF PHYSIOLOGY, Issue 3 2001Frank A. Dinenno 1Basal whole-limb blood flow and vascular conductance decrease with age in men. We determined whether these age-associated changes in limb haemodynamics are mediated by tonically augmented sympathetic ,-adrenergic vasoconstriction. 2Seven young (28 ± 2 years; mean ±s.e.m.) and eight older (64 ± 2 years) healthy, normotensive adult men were studied. Baseline femoral artery blood flow (Doppler ultrasound) and calculated vascular conductance were 29 and 31 % lower, respectively, and vascular resistance was 53 % higher in the older men (all P < 0.001). 3Local (intra-femoral artery) ,-adrenergic receptor blockade with phentolamine evoked greater increases in femoral blood flow (105 ± 11 vs. 60 ± 6 %) and vascular conductance (125 ± 13 vs. 66 ± 7 %), and reductions in vascular resistance (55 ± 2 vs. 39 ± 3 %) in the experimental limb of the older compared with the young men (all P < 0.001). As a result, ,-adrenergic receptor blockade eliminated the significance of the age-associated differences in absolute levels of femoral blood flow (500 ± 51 vs. 551 ± 35 ml min,1), vascular conductance (6.02 ± 0.73 vs. 6.33 ± 0.26 U), and vascular resistance (0.17 ± 0.03 vs. 0.16 ± 0.01 U; P= 0.4,0.8, n.s.). Femoral haemodynamics in the control limb were unaffected by phentolamine administration in the contralateral (experimental) limb. Complete ,-adrenergic receptor blockade was demonstrated by the absence of vasoconstriction in the experimental limb in response to the cold pressor test. Local propranolol was administered to control for any ,-adrenergic effects of phentolamine. Propranolol did not affect haemodynamics in the experimental or control limbs. 4Our results indicate that the age-related reductions in basal limb blood flow and vascular conductance are mediated largely by chronically elevated sympathetic ,-adrenergic vasoconstriction. This may have important physiological and pathophysiological implications for the ageing human. [source] A Novel Subcutaneous Counterpulsation Device: Acute Hemodynamic Efficacy During Pharmacologically Induced Hypertension, Hypotension, and Heart FailureARTIFICIAL ORGANS, Issue 7 2010Carlo R. Bartoli Abstract The miniaturization of mechanical assist devices and less invasive implantation techniques may lead to earlier intervention in patients with heart failure. As such, we evaluated the effectiveness of a novel, minimally invasive, implantable counterpulsation device (CPD) in augmenting cardiac function during impaired hemodynamics. We compared the efficacy of a 32-mL stroke volume CPD with a standard 40-mL intra-aortic balloon pump (IABP) over a range of clinically relevant pathophysiological conditions. Male calves were instrumented via thoracotomy, the CPD was anastomosed to the left carotid artery, and the IABP was positioned in the descending aorta. Hemodynamic conditions of hypertension, hypotension, and heart failure were pharmacologically simulated and data were recorded during CPD and IABP support (off, 1:2, 1:1 modes) for each condition. In all three pathophysiological conditions, the CPD and IABP produced similar and statistically significant (P < 0.05) increases in coronary artery blood flow normalized to the left ventricular (LV) workload. During hypotension and heart failure conditions, however, the CPD produced significantly greater reductions in LV workload and myocardial oxygen consumption as compared with the IABP. A novel 32-mL CPD connected to a peripheral artery produced equivalent or greater hemodynamic benefits than a standard 40-mL IABP during pharmacologically induced hypertension, hypotension, and heart failure conditions. [source] Retinal vascular findings and penile cavernosal artery blood flowBJU INTERNATIONAL, Issue 9 2003Y. Kawanishi Authors from Japan attempt to correlate retinal vascular changes with cavernosal arterial blood flow. They studied patients with erectile dysfunction, but excluded patients with previous pelvic surgery, pelvic injury or diabetes. They found that penile changes can be anticipated from retinal vascular changes seen on fundoscopy. OBJECTIVE To assess the correlation between retinal vascular findings and penile cavernosal arterial blood flow, as it is probable that systemic atherosclerotic vascular disease is important in male erectile dysfunction (ED), and being systemic, it might be possible to evaluate the extent of atherosclerosis from retinal vascular findings. PATIENTS AND METHODS The study included 75 patients with ED; any with a history of pelvic injury, pelvic surgery, or diabetes mellitus were excluded. All patients gave fully informed consent. Ocular fundus photographs were taken with an automatic-focus fundus camera under amydriatic conditions. Three ophthalmologists, unaware of the patients' detailed data, evaluated the photographs using Hyman's classification to evaluate retinal vascular findings. Blood flow in the penile cavernosal artery was measured with colour Doppler ultrasonography, and the peak systolic velocity used as a haemodynamic variable. Correlations among the peak systolic velocity, retinal vascular findings and vascular risk factors (including hypertension, age, cigarette smoking, and hyperlipidaemia) were investigated using multivariate analysis. RESULTS Of the 75 patients, 72 (96%) had both right and left retinal vascular images of sufficient quality for evaluation; 37 were classified as normal and 35 as Grade I, while no patient was Grade II. From a logistic regression multivariate analysis, the peak systolic velocity was the only significant factor correlating with retinal vascular findings, with an odds ratio of 3.34. In contrast, hypertension, age, cigarette smoking and hyperlipidaemia did not correlate significantly with the retinal vascular findings. Similarly, the retinal vascular finding was the only significant factor correlating with the peak systolic velocity of cavernosal blood flow (odds ratio 3.28) and again hypertension, age, cigarette smoking and hyperlipidaemia were not significant factors. CONCLUSIONS These findings support the assumption that penile erectile function is one of the diseases of atherosclerosis, and emerges nearly simultaneously with retinal vascular disease. It is possible to predict penile arterial conditions in patients with ED from their retinal vascular findings. Thus, amydriatic fundoscopy, a simple practical examination, may be helpful for primary physicians in diagnosing and treating ED. [source] In vivo evaluation of an implantable portal pump system for augmenting liver perfusionBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 8 2000L. R. Jiao Background Increasing portal inflow in cirrhosis using a mechanical pump reduces portal venous pressure and improves liver function. A pump has been developed for portal vein implantation in human cirrhosis. This study describes the initial in vivo evaluation in a porcine model. Methods Five Large White pigs underwent laparotomy and exposure of the liver. Flow in the hepatic artery, portal vein and hepatic microcirculation was monitored continuously. Hepatic tissue oxygenation was measured by near-infrared spectroscopy. After baseline measurements the pump was inserted into the portal vein. Pump flow rate was then increased stepwise to 50 per cent over the baseline value for a period of 2 h. The pump was then stopped for 20 min and left in situ while continuing to collect systemic and hepatic haemodynamic data. The animal was killed and biopsies for histological examination were taken from the liver, small intestine and spleen. Results The baseline total hepatic blood flow was 626(39) ml/min; the hepatic artery supplied 18·4(2·1) per cent and the portal vein 81·6(2·1) per cent. The pump was inserted successfully in all animals without surgical complications. During surgical insertion of the pump, the temporary portal vein occlusion resulted in a significant rise in hepatic artery blood flow (22(3) per cent; P < 0·01 versus baseline). Portal vein flow was augmented by pumping; there was a significant correlation between the pump motor speed and portal vein flow (P < 0·0001). This inflow correlated directly with flow in the hepatic microcirculation and hepatic tissue oxygenation (P < 0·001). The pump ran satisfactorily throughout the study. Histological examination revealed no evidence of structural damage to the liver or ischaemic changes in the small intestine or spleen. Conclusion It is technically possible and safe to insert an implantable pump in the portal vein. Portal venous blood flow can be increased up to 50 per cent with a resultant increase in flow in the hepatic microcirculation and hepatic oxygenation and without adverse effects on either hepatic or systemic haemodynamics. © 2000 British Journal of Surgery Society Ltd [source] Rupture of a peripheral popliteal artery plaque documented by intravascular ultrasound: A case report,CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 7 2009Hiroaki Kohno MD Abstract A 58-year-old male with dyslipidemia and coronary spastic angina suddenly experienced pain in the right limb while walking on November 1, 2008. Right-ankle brachial pressure index (ABI) was decreased (0.80) and left-ABI was normal (1.24). Bilateral ABI was normal during January 2008. Ultrasonography in the right-lower limb artery revealed severe stenosis in the right-popliteal artery with extended and large echolucent plaques containing an isoechoic area. We carried out lower limb angiography: subtotal occlusion of the popliteal artery was found. By intravascular ultrasound (IVUS), right-popliteal artery plaques were echolucent and eccentric; ulceration with a thin fibrous cap was noted. Percutaneous transluminal angioplasty was done and popliteal artery blood flow was improved. Right-ABI improved to 1.13 after 4 days. To prevent the progression and rupture of the plaques, lipid-lowering therapy and antiplatelet therapy were started. Plaque rupture of the popliteal artery was diagnosed by these characteristics on IVUS. Patients with peripheral artery disease may have plaque rupture similar to those with acute coronary syndromes who have identical unstable plaques and unstable atheromas. In addition to appropriate local revascularization, systemic therapy to stabilize the unstable plaque is indicated because failure to do so may cause recurrent events. © 2009 Wiley-Liss, Inc. [source] Reperfusion of myocardium does not necessarily equate with epicardial coronary artery blood flowCLINICAL CARDIOLOGY, Issue 11 2004C. Richard Conti M.D., M.A.C.C. Editor-in-Chief [source] Assessment of coronary blood flow and the reactivity of the microcirculation non-invasively with transthoracic echocardiographyCLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 3 2008Tuomas Kiviniemi Summary Background:, The development in ultrasound technology has allowed the use of non-invasive transthoracic echocardiography (TTE) for the study of coronary artery physiology and pathophysiology. TTE can be used to detect atherosclerotic changes in epicardial coronary arteries and to study the effects of specific interventions on coronary microcirculation. Aim:, The purpose of this review was to summarize the development of TTE, and outweigh the strenghts and weaknesses of the method for the evaluation of coronary artery blood flow. Moreover, findings from clinical trials studying microcirculatory reactivity using TTE are presented. Conclusions:, TTE is a feasible and reproducible method for the evaluation of coronary artery blood flow. It can also be used in assessing the vasodilation of the epicardial coronary artery simultaneously with flow velocity measurement during the cold pressor test and coronary flow velocity reserve assessment. It is specifically suitable for repeated measurements in interventional trials. [source] Effect of fat digestion on superior mesenteric artery blood flow in humansCLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 1 2007T. Symersky Summary Background and aim:, Intraluminal nutrients stimulate superior mesenteric artery (SMA) blood flow. Of the macronutrients, especially fat affects the magnitude of the SMA blood flow response to a meal. Little is known however on the influence of fat hydrolysis on SMA flow. Methods:, We compared in eight healthy volunteers the SMA flow response (Doppler ultrasonography) to continuous intraduodenal fat perfusion (LCT, 240 kCal h,1) during conditions with normal hydrolysis (placebo, control), increased hydrolysis (pancreatic enzyme supplementation; 50 kU lipase) and impaired hydrolysis (orlistat 240 mg). Results:, Intraduodenal LCT significantly (P<0·01) increased SMA flow in all experiments over basal. The SMA flow response to fat during pancreatic enzyme supplementation (1·49 ± 0·1 l min,1) was significantly (P<0·05) higher compared with placebo (1·11 ± 0·16 l min,1). Lipase inhibition with orlistat did not significantly affect fat stimulated SMA flow compared with placebo: 0·89 ± 0·08 l min,1 versus 1·11 ± 0·16 l min,1. Conclusions:, Administration of pancreatic enzymes significantly increases fat stimulated SMA flow. Fat digest products in the intestinal lumen contribute to the regulation of SMA blood flow. [source] Hyperoxia-induced arterial compliance decrease in healthy manCLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 1 2005Pascal Rossi Summary Introduction:, Oxygen therapy is commonly used in emergency department and intensive care units without careful evaluation of its effects, especially on the haemodynamics and artery characteristics. Materials and methods:, A prospective laboratory study evaluated brachial circulatory effects of normobaric hyperoxia using ultrasonography-Doppler. The study was set in a hospital research laboratory. The subjects were thirteen healthy volunteers. Investigations were performed under normal air ventilation and after 20 min of hyperoxic mixture ventilation using a high concentration mask. Two dimensional images and brachial blood flow velocities were recorded using ultrasonography and pulsed Doppler to study changes in cross sectional area, blood flow, resistance index, and cross-sectional compliance coefficient. Results:, During hyperoxic exposure, mean PaO2 was 372 ± 21 mmHg. A significant decrease of heart rate was observed. Arterial pressures (systolic and diastolic arterial pressures) were not modified. A decrease of cross sectional areas at end diastole and end systole was observed. Pulsed Doppler study showed a decrease of brachial artery blood flow and an increase of the resistance index. Furthermore, a decrease of the cross-sectional compliance coefficient was observed during hyperoxic exposure in all subjects. Conclusion:, This study using two-dimensional ultrasonography and pulsed Doppler could demonstrate an increase in brachial arterial tone and a decrease in brachial blood flow under normobaric hyperoxia. [source] | ||||||||||||||||||||||