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Arterial
Kinds of Arterial Terms modified by Arterial Selected AbstractsCerebral oxygenation decreases during exercise in humans with beta-adrenergic blockadeACTA PHYSIOLOGICA, Issue 3 2009T. Seifert Abstract Aim:, Beta-blockers reduce exercise capacity by attenuated increase in cardiac output, but it remains unknown whether performance also relates to attenuated cerebral oxygenation. Methods:, Acting as their own controls, eight healthy subjects performed a continuous incremental cycle test to exhaustion with or without administration of the non-selective beta-blocker propranolol. Changes in cerebral blood flow velocity were measured with transcranial Doppler ultrasound and those in cerebral oxygenation were evaluated using near-infrared spectroscopy and the calculated cerebral mitochondrial oxygen tension derived from arterial to internal jugular venous concentration differences. Results:, Arterial lactate and cardiac output increased to 15.3 ± 4.2 mm and 20.8 ± 1.5 L min,1 respectively (mean ± SD). Frontal lobe oxygenation remained unaffected but the calculated cerebral mitochondrial oxygen tension decreased by 29 ± 7 mmHg (P < 0.05). Propranolol reduced resting heart rate (58 ± 6 vs. 69 ± 8 beats min,1) and at exercise exhaustion, cardiac output (16.6 ± 3.6 L min,1) and arterial lactate (9.4 ± 3.7 mm) were attenuated with a reduction in exercise capacity from 239 ± 42 to 209 ± 31 W (all P < 0.05). Propranolol also attenuated the increase in cerebral blood flow velocity and frontal lobe oxygenation (P < 0.05) whereas the cerebral mitochondrial oxygen tension decreased to a similar degree as during control exercise (delta 28 ± 10 mmHg; P < 0.05). Conclusion:, Propranolol attenuated the increase in cardiac output of consequence for cerebral perfusion and oxygenation. We suggest that a decrease in cerebral oxygenation limits exercise capacity. [source] "Supranormal" Cardiac Function in Athletes Related to Better Arterial and Endothelial FunctionECHOCARDIOGRAPHY, Issue 6 2010Maria Florescu M.D. Objective: Athlete's heart is associated with left ventricular (LV) hypertrophy (LVH), and "supranormal" cardiac function, suggesting that this is a physiological process. Hypertrophy alone cannot explain increase in cardiac function, therefore, other mechanisms, such as better ventriculo-arterial coupling might be involved. Methods: We studied 60 male (21 ± 3 years) subjects: 27 endurance athletes, and a control group of 33 age-matched sedentary subjects. We assessed global systolic and diastolic LV function, short- and long-axis myocardial velocities, arterial structure and function and ventriculo-arterial coupling, endothelial function by flow-mediated dilatation, and amino-terminal pro-brain natriuretic peptide (NT-proBNP) and biological markers of myocardial fibrosis and of oxidative stress. Results: Athletes had "supranormal" LV longitudinal function (12.4 ± 1.0 vs 10.1 ± 1.4 cm/s for longitudinal systolic velocity, and 17.4 ± 2.6 vs 15.1 ± 2.4 cm/s for longitudinal early diastolic velocity, both P < 0.01), whereas ejection fraction and short-axis function were similar to controls. Meanwhile, they had better endothelial function (16.7 ± 7.0 vs 13.3 ± 5.3%, P < 0.05) and lower arterial stiffness (pulse wave velocity 7.1 ± 0.6 vs 8.8 ± 1.1 m/s, P = 0.0001), related to lower oxidative stress (0.259 ± 0.71 vs 0.428 ± 0.88 nmol/mL, P = 0.0001), with improved ventriculo-arterial coupling (37.1 ± 21.5 vs 15.5 ± 13.4 mmHg.m/s3× 103, P = 0.0001). NT-proBNP and markers of myocardial fibrosis were not different from controls. LV longitudinal function was directly related to ventriculo-arterial coupling, and inversely related to arterial stiffness and to oxidative stress. Conclusions: "Supranormal" cardiac function in athletes is due to better endothelial and arterial function, related to lower oxidative stress, with optimized ventriculo-arterial coupling; athlete's heart is purely a physiological phenomenon, associated with "supranormal" cardiac function, and there are no markers of myocardial fibrosis. (Echocardiography 2010;27:659-667) [source] Short-term cortisol infusion in the brachial artery, with and without inhibiting 11,-hydroxysteroid dehydrogenase, does not alter forearm vascular resistance in normotensive and hypertensive subjectsEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 12 2002S. H. M. Van Uum Abstract Background Vascular tone is increased in primary hypertension, and glucocorticoids affect vascular tone. Local cortisol availability is modulated by activity of 11,-hydroxysteroid dehydrogenase (11,-HSD). As this activity may be decreased in patients with primary hypertension, vascular sensitivity to cortisol may be increased in these patients. We studied the acute effect of cortisol on forearm vascular resistance (FVR) by infusing cortisol directly into the brachial artery, both with and without inhibition of 11,-HSD, in normotensive and hypertensive subjects. Design Twenty normotensive volunteers and 20 patients with primary hypertension participated in the study. After a 10-min infusion of vehicle (glucose 5%), cortisol was infused into the brachial artery in three stepwise increasing doses (3·5, 10·5 and 35 µg per 100 mL of forearm volume), each for 10 min. Next, the participants received placebo or 500 mg glycyrrhetinic acid (GA) orally, and 150 min later the same infusion schedule was repeated. Forearm vascular resistance was measured during the last 5 min of the infused vehicle and of each dose. Arterial and forearm venous plasma samples for measurement of cortisol and cortisone were taken at the end of the infusions of glucose 5% and the highest cortisol dose. Results In both normotensive and hypertensive subjects, neither the infusion of cortisol nor the administration of GA changed FVR. Also 2 h after the cortisol infusion there remained no change in FVR in both the normotensive and hypertensive groups who received placebo. Following the infusion of the highest cortisol dose, total plasma cortisone levels in the venous plasma were decreased compared with levels in the arterial plasma (36 ± 3 and 49 ± 4 nmol L,1, respectively, P < 0·05). The protein-bound venous cortisone was 37·1 ± 4·8 nmol L,1 during the vehicle compared with 23·9 ± 3·7 nmol L,1 during the cortisol infusion (P < 0·01), whereas the free cortisone level was not altered by the cortisol infusion. Conclusions In both normotensive and hypertensive subjects, high-dose cortisol infusion both with and without 11,-HSD inhibition did not change FVR either immediately or after 2 h. We could not demonstrate in vivo 11,-HSD activity in the forearm vascular tissues. When binding of cortisone to CBG is changed, e.g. during cortisol infusion, arterio-venous changes in cortisone cannot reliably be used to assess (alterations in) local 11,-HSD activity. [source] Leg ulcers and hydroxyurea: report of three cases with essential thrombocythemiaINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 12 2002Zeynep Demirçay MD Case 1,A 65-year-old woman with essential thrombocythemia (ET) had been taking oral hydroxyurea (HU), 1000 mg daily, for 7 years. Six months ago, she developed an ulcer on the outer part of her left ankle, which healed spontaneously within 2 months. She presented with a new, tender, shallow ulcer, 2 cm × 2 cm in size, at the same site. Doppler examination revealed thrombosis of the left common femoral vein and a calcified atheroma plaque of the left common femoral artery. The dosage of HU was decreased to 500 mg daily when the platelet counts were found to be within normal levels. The ulcer completely healed within 2 months with occlusive wound dressings, and has not recurred within the follow-up period of 1 year. Case 2,A 56-year-old women presented with multiple, painful, leg ulcers of 1 year duration. She had been diagnosed as having ET and had been on HU therapy, 1500 mg/day, for the past 5 years. Interferon-,-2b was started 3 months ago, in addition to HU, which was tapered to 1000 mg daily. She had suffered from hypertension for 20 years treated with nifedipine and enalapril, and had recently been diagnosed with diabetes mellitus which was controlled by diet. Examination revealed three ulcers located on the lateral aspects of both ankles and right distal toe. Arterial and venous Doppler examinations were within normal limits. Histopathology of the ulcer revealed nonspecific changes with a mixed inflammatory cell infiltrate around dermal vessels. The ulcers completely healed within 10 weeks with topical hydrocolloid dressings. After healing, she was lost to follow-up. A year later, it was learned that she had developed a new ulcer at her right heel, 3 months after her last visit (by phone call). This ulcer persisted for 8 months until HU was withdrawn. Case 3,A 64-year-old woman with ET presented with a painful leg ulcer of 6 months' duration. She had been taking oral HU for 5 years. She had a 20-year history of hypertension treated with lisinopril. Examination revealed a punched-out ulcer of 2 cm × 2 cm over the right lateral malleolus (Fig. 1). Doppler examination of the veins revealed insufficiency of the right greater saphenous and femoral veins. Angiography showed multiple stenoses of the right popliteal and femoral arteries. As her platelet count remained high, HU was continued. During the follow-up period of 13 months, the ulcer showed only partial improvement with local wound care. Figure 1. Punched-out ulcer surrounded by an erythematous border over the right malleolus (Case 3) [source] Percutaneous Left and Right Heart Catheterization in Fully Anticoagulated Patients Utilizing the Radial Artery and Forearm Vein: A Two-Center ExperienceJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 3 2006TED S. N. LO M.R.C.P. Background: Stopping oral anticoagulants prior to cardiac catheterization is associated with an increased risk of thromboembolism. Performing the procedures via the femoral artery and vein without interruption of anticoagulation is associated with a high rate of major access site complications. The transradial technique for left heart catheterization is safe in fully anticoagulated patients but few data are available on the percutaneous right and left heart catheterization utilizing a combination of the radial artery and antecubital vein in this group of patients. Methods: We report our experience in 28 consecutive patients that underwent left and right heart catheterizations via this percutaneous arm approach without interruption of anticoagulation. These were compared to 31 consecutive non-anticoagulated patients that underwent the procedure via a conventional femoral artery and vein approach. Results: Arterial and venous accesses were achieved and complete angiographic and hemodynamic data obtained in all patients. There were no access site complications in the anticoagulated patients despite an International normalized ratio (INR) of 2.5 ± 0.5. Procedural duration was longer in the anticoagulated group of patients, but fluoroscopy time and patient radiation dose were similar in both groups. Conclusion: Our experience suggests that left and right heart catheterization can be safely performed in most fully anticoagulated patients using this technique with a low bleeding and thromboembolic risk and no increase in radiation exposure. [source] Percutaneous Suture Closure for Management of Large French Size Arterial and Venous PunctureJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 4 2000TED FELDMAN M.D. Aortic valvuloplasty procedures have been limited principally by the occurrence of restenosis in this patient population. Once a decision has been made to proceed with aortic valvuloplasty, one of the next major concerns is management of the femoral artery puncture. For these procedures, 12Fr and 14Fr sheath introducers and prolonged compression with clamps or hemostatic devices have been necessary. Prolonged immobilization is painful for the elderly population in whom aortic valvuloplasty is used. The ability to use percutaneous suture closure to eliminate the need for manual compression, especially for clamp or hemostatic devices, has greatly improved patient tolerance for these procedures. A technique for preloading the suture closure device prior to insertion of a large bore sheath is the technique of choice to make this possible. Mitral valvuloplasty has faced fewer limitations and of course yields results equivalent to surgical commissurotomy in randomized trials. Improved management of the 14Fr femoral venous site has made outpatient treatment simpler. The technical approach necessary for success in the venous system uses contrast injections through the Perclose device marker port to insure that the device is properly positioned prior to deployment of the sutures. More rapid immobilization and simplified postprocedural management can be achieved using percutaneous suture closure for large caliber sheaths after mitral and aortic valvuloplasty. [source] Evaluation of Quantitative Portal Venous, Hepatic Arterial, and Total Hepatic Tissue Blood Flow Using Xenon CT in Alcoholic Liver Cirrhosis,Comparison With Liver Cirrhosis Related to Hepatitis C Virus and Nonalcoholic SteatohepatitisALCOHOLISM, Issue 2010Hideaki Takahashi Background/Aims:, Xenon computed tomography (Xe-CT) is a noninvasive method of quantifying and visualizing tissue blood flow (TBF). For the liver, Xe-CT allows separate measurement of hepatic arterial and portal venous TBF. The present study evaluated the usefulness of Xe-CT as a noninvasive diagnostic procedure for measuring hepatic TBF in alcoholic liver cirrhosis (AL-LC), compared with liver cirrhosis related to nonalcoholic steatohepatitis (NASH), (NASH-LC), and hepatitis C virus (HCV), (C-LC). Methods:, Xe-CT was performed on 22 patients with AL-LC, 7 patients with NASH-LC, and 24 patients with C-LC. Severity of LC was classified according to Child-Pugh classification. Correlations between hepatic TBF, Child-Pugh classification, and indocyanin green retention (ICG) rate after 15 minutes (ICG15R) were examined. Correlations of hepatic TBF in Child-Pugh class A to AL-LC, NASH-LC, and C-LC were also examined. Results:, Portal venous TBF (PVTBF) displayed a significant negative correlation with Child-Pugh score and ICG15R (r = ,0.432, p < 0.01, r = ,0.442, p < 0.01, respectively). Moreover, ICG15R displayed a significant positive correlation with Child-Pugh score (r = 0.661, p < 0.001). Meanwhile, mean PVTBF and total hepatic TBF (THTBF) was significantly lower in AL-LC than in C-LC (p < 0.05). Mean PVTBF was significantly lower in Child-Pugh class A to AL-LC and NASH-LC than in that to C-LC (p < 0.05). Similarly, mean THTBF was significantly lower in Child-Pugh class A to NASH-LC than in that to C-LC (p < 0.05). Conclusions:, Measurement of hepatic TBF using Xe-CT is useful as a noninvasive, objective method of assessing the state of the liver in chronic liver disease. [source] Dexmedetomidine during coronary artery bypass grafting surgery: is it neuroprotective?ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 8 2007A preliminary study Background:, In the present study, we aimed to determine whether during coronary artery bypass grafting (CABG) surgery, dexmedetomidine has protective effects against cerebral ischemic injury. Method:, Twenty-four patients, aged 50,70 years, undergoing CABG surgery were randomized into two groups of 12 patients each: those receiving dexmedetomidine (group D) and those not receiving it (group C). As basal blood samples from arterial and jugular bulb catheters were drawn, dexmedetomidine (1 ,g/kg bolus and infusion at a rate of 0.7 ,g/kg/h) was administered to patients in group D. Arterial and jugular venous blood gas analyses, serum S-100B protein (S-100B), neuron-specific enolase (NSE) and lactate measurements were performed after induction, 10 min after the initiation of cardiopulmonary bypass (CPB), 1 min after declamping, at the end of CPB, at the end of the operation and 24 h after surgery. Mann,Whitney U - and Wilcoxon's tests were used for statistical analyses. Results:, No significant between-group differences were found regarding arterial and jugular venous pH, PO2, PCO2 and O2 saturations. S-100B, NSE and lactate levels were also similar between groups D and C. During the post-operative period, there were no clinically overt neurological complications in any patient. Conclusion:, Cerebral ischemia marker (S-100B, NSE, lactate) patterns were as expected during CPB; however, there were no differences between the groups, which led us to believe that during CABG surgery dexmedetomidine has no neuroprotective effects. Future studies with larger populations are recommended to further establish the effects of this drug. [source] Evaluation of hematological, chemistry and blood gas values in dogs receiving hemoglobin glutamer-200JOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue 1 2007DACVECC, DACVIM, Marie E. Kerl DVM Abstract Objective: To evaluate the degree of interference that administration of hemoglobin glutamer-200 (Hb-200) caused for complete blood counts (CBC), biochemical profiles, cooximetry, and point of care (POC) testing in healthy dogs. Design: Prospective, longitudinal experimental study. Setting: Veterinary medical teaching hospital. Animals: Six purpose-bred research hounds. Interventions: Dogs were administered FDA-approved hemoglobin-based oxygen carrier (Hb-200) intravenously at 7.5 mL/kg over 2 hours. Arterial and venous blood samples were obtained before administration (Time 0) and at 3, 8, 14, 26, 50, 74, 98, 122, and 146 hours following administration. Measurements and main results: No adverse health effects were observed in any of the dogs. Characteristic mucous membrane, serum, and plasma color changes occurred following administration of Hb-200. Laboratory values that were significantly lower than baseline included packed cell volume, red blood cell count, hemoglobin, hematocrit, creatinine, cholesterol, alanine aminotransferase, and alkaline phosphatase. Laboratory values that were significantly greater than baseline included mean corpuscular hemoglobin concentration, arterial pH, arterial total carbon dioxide, arterial bicarbonate, amylase, albumin, total protein, globulin, calcium, phosphorous, total bilirubin, carboxyhemoglobin, and methemoglobin. All values returned to baseline by the completion of the 146-hour monitoring period. Conclusions: In normal dogs, administration of Hb-200 resulted in statistically significant changes in multiple laboratory parameters; however, these changes are not likely to be clinically significant in the care of critically ill dogs. [source] Relationship of Ultrafiltration and Anastomotic Flow in Isolated Rat LungsMICROCIRCULATION, Issue 5 2001WEN LIN ABSTRACT Objective: When arterial and venous pressures are increased to equal values in "stop-flow" studies, perfusate continues to enter the pulmonary vasculature from the arterial and venous reservoirs. Losses of fluid from the pulmonary vasculature are due to ultrafiltration and flow through disrupted anastomotic (bronchial) vessels. This study compared the relative sites of ultrafiltration and anastomotic flows at low and high intravascular pressures. Methods: Isolated rat lungs were perfused for 10 minutes with FITC-dextran, which was used to detect ultrafiltration. Arterial and venous catheters were then connected to reservoirs containing radioactively labeled dextrans at 20 or 30 cm H2O for 10 minutes. The vasculature was subsequently flushed into serial vials, and ultrafiltration and vascular filling during the equal-pressure interval were calculated. Results: Ultrafiltration equaled 0.43 ± 0.11 mL at 20 cm H2O and was similar to the volume of fresh arterial and venous perfusate which entered and remained in the pulmonary vasculature during the equal-pressure interval (0.45 ± 0.10 mL). At 30 cm H2O, 0.80 ± 0.23 mL entered and remained in the vasculature during the equal-pressure interval, replacing the original perfusate, and calculated transudation (0.56 ± 0.09 mL) was not significantly more than at 20 cm H2O. Fluid also entered the airspaces at 30 cm H2O but not at 20 cm H2O. Conclusions: At 20 cm H2O, flow through anastomotic vessels occurs at sites that are at the arterial and venous ends of the microcirculation. Flow in exchange vessels remains minimal, permitting measurements of ultrafiltration and exchange. Losses of perfusate from the pulmonary vessels complicate measurements of ultrafiltration at 30 cm H2O. [source] Versatility of vertical rectus abdominis musculocutaneous flapsMICROSURGERY, Issue 5 2006Markus V. Küntscher M.D., Ph.D. The purpose of the study was to demonstrate a variety of indications for the vertical rectus abdominis musculocutaneous (VRAM) flap with respect to donor-site morbidity and alternative procedures. Fifteen VRAM flaps were performed in 15 patients during a 4-year period. The average age of patients was 58 years (range, 34,76 years). Inferiorly based VRAM flaps were used for defect coverage after tumor resection and for penile reconstruction in 7 cases. Superiorly based VRAM flaps were performed in 7 cases for reconstruction of osteocutaneous defects following sternal osteomyelitis and tumor resection. Arterial and venous "supercharging" was necessary in one case. One free VRAM flap was performed in a patient suffering from an osteocutaneous defect after resection of a malignant melanoma metastasis with infiltration of the brain and skull. The reconstructive goals were achieved in all cases using VRAM flap procedures. No total flap loss occurred. Minor complications as well as abdominal wall bulging and hernias were observed in four cases. The pedicled VRAM flap provides a reliable tool for coverage of large soft-tissue defects of the chest wall, groin, hip, and perineum even in a high-risk population, in which a safe and fast forward flap procedure is the primary reconstructive goal. Arterial and/or venous supercharging may be necessary, particularly in superiorly based VRAM flaps. An inferiorly based VRAM flap is a reliable tool for phalloplasty under special circumstances. The indication for free VRAM flaps is given in rare clinical situations. Stabilization of the donor site using artificial mesh is highly recommended. © 2006 Wiley-Liss, Inc. Microsurgery, 2006. [source] Intestinal and hepatic metabolism of glutamine and citrulline in humansTHE JOURNAL OF PHYSIOLOGY, Issue 2 2007Marcel C. G. Van De Poll Glutamine plays an important role in nitrogen homeostasis and intestinal substrate supply. It has been suggested that glutamine is a precursor for arginine through an intestinal,renal pathway involving inter-organ transport of citrulline. The importance of intestinal glutamine metabolism for endogenous arginine synthesis in humans, however, has remained unaddressed. The aim of this study was to investigate the intestinal conversion of glutamine to citrulline and the effect of the liver on splanchnic citrulline metabolism in humans. Eight patients undergoing upper gastrointestinal surgery received a primed continuous intravenous infusion of [2- 15N]glutamine and [ureido- 13C,2H2]citrulline. Arterial, portal venous and hepatic venous blood were sampled and portal and hepatic blood flows were measured. Organ specific amino acid uptake (disposal), production and net balance, as well as whole body rates of plasma appearance were calculated according to established methods. The intestines consumed glutamine at a rate that was dependent on glutamine supply. Approximately 13% of glutamine taken up by the intestines was converted to citrulline. Quantitatively glutamine was the only important precursor for intestinal citrulline release. Both glutamine and citrulline were consumed and produced by the liver, but net hepatic flux of both amino acids was not significantly different from zero. Plasma glutamine was the precursor of 80% of plasma citrulline and plasma citrulline in turn was the precursor of 10% of plasma arginine. In conclusion, glutamine is an important precursor for the synthesis of arginine after intestinal conversion to citrulline in humans. [source] Presumed perinatal ischemic stroke: Vascular classification predicts outcomesANNALS OF NEUROLOGY, Issue 4 2008Adam Kirton MD, FRCPC Objective Perinatal stroke commonly causes childhood neurological morbidity. Presumed perinatal ischemic stroke (PPIS) defines children presenting outside a normal perinatal period with chronic, focal infarction on neuroimaging. Infarcts are assumed to represent arterial strokes, but recent evidence suggests the periventricular venous infarction (PVI) of infants born preterm may also occur in utero and present as PPIS. Using the largest published cohort, we aimed to define arterial and PVI PPIS syndromes and their outcomes. Methods A PPIS consecutive cohort was identified (SickKids Children's Stroke Program, 1992,2006). Systematic neuroradiological scoring executed by blinded investigators included previously defined arterial stroke syndromes. PVI criteria included unilateral injury with at least four of the following conditions: (1) focal periventricular encephalomalacia, (2) internal capsule T2 prolongation, (3) cortical and (4) relative basal ganglia sparing, and (5) remote hemorrhage. Arterial and PVI classifications were validated and correlated with neurological outcomes (Pediatric Stroke Outcome Measure). Results In 59 PPISs (64% male), 94% of lesions fell within potential middle cerebral artery territories. Although arterial proximal M1 infarction was most common (n = 19; 35%), venous PVI was second (n = 12; 22%) and accounted for 75% of subcortical injuries. Motor outcomes (mean follow-up, 5.3 years) were predicted by basal ganglia involvement including leg hemiparesis, spasticity, and need for assistive devices (p < 0.01). Nonmotor outcomes were associated with cortical involvement, including cognitive/behavioral outcomes, visual deficits, and epilepsy (p < 0.01). Classification interrater reliability was excellent (correlation coefficients > 0.975). Interpretation Recognizable PPIS patterns predict long-term morbidity and may guide surveillance, therapy, and counseling. PVI is an underrecognized cause of PPIS and congenital hemiplegia. Ann Neurol 2008 [source] Randomized trial comparing natural and synthetic surfactant: increased infection rate after natural surfactant?ACTA PAEDIATRICA, Issue 5 2000AK Kukkonen The efficacy of a natural porcine surfactant and a synthetic surfactant were compared in a randomized trial. In three neonatal intensive care units, 228 neonates with respiratory distress and a ratio of arterial to alveolar partial pressure of oxygen <0.22 were randomly assigned to receive either Curosurf 100mgkg,1 or Exosurf Neonatal 5 ml kg,1. After Curosurf, the fraction of inspired oxygen was lower from 15min (0.45 ± 0.22 vs 0.70 ± 0.22, p = 0.0001) to 6 h (0.48 ± 0.26 vs 0.64 ± 0.23,p= 0.0001) and the mean airway pressure was lower at 1 h (8.3 3.2 mmH2O vs 9.4 ± 3.1 mmH2O ,= 0.01). Thereafter the respiratory parameters were similar. The duration of mechanical ventilation (median 6 vs 5 d) and the duration of oxygen supplementation (median 5 vs 4 d) were similar for Curosurf and Exosurf After Curosurf, C-reactive protein value over 40 mg r1 occurred in 45% (vs 12%; RR 3.62, 95%CI 2.12-6.17, p = 0.001), leukopenia in 52% (vs 28%; RR 1.85, 95%CI 1.31-2.61, ,= 0.001) and bacteraemia in 11% (vs 4%; RR3.17, 95%CI 1.05-9.52, p < 0.05). We conclude that when given as rescue therapy Curosurf had no advantage compared with Exosurf in addition to the more effective initial response. Curosurf may increase the risk of infection. [source] Cerebral oxygenation decreases during exercise in humans with beta-adrenergic blockadeACTA PHYSIOLOGICA, Issue 3 2009T. Seifert Abstract Aim:, Beta-blockers reduce exercise capacity by attenuated increase in cardiac output, but it remains unknown whether performance also relates to attenuated cerebral oxygenation. Methods:, Acting as their own controls, eight healthy subjects performed a continuous incremental cycle test to exhaustion with or without administration of the non-selective beta-blocker propranolol. Changes in cerebral blood flow velocity were measured with transcranial Doppler ultrasound and those in cerebral oxygenation were evaluated using near-infrared spectroscopy and the calculated cerebral mitochondrial oxygen tension derived from arterial to internal jugular venous concentration differences. Results:, Arterial lactate and cardiac output increased to 15.3 ± 4.2 mm and 20.8 ± 1.5 L min,1 respectively (mean ± SD). Frontal lobe oxygenation remained unaffected but the calculated cerebral mitochondrial oxygen tension decreased by 29 ± 7 mmHg (P < 0.05). Propranolol reduced resting heart rate (58 ± 6 vs. 69 ± 8 beats min,1) and at exercise exhaustion, cardiac output (16.6 ± 3.6 L min,1) and arterial lactate (9.4 ± 3.7 mm) were attenuated with a reduction in exercise capacity from 239 ± 42 to 209 ± 31 W (all P < 0.05). Propranolol also attenuated the increase in cerebral blood flow velocity and frontal lobe oxygenation (P < 0.05) whereas the cerebral mitochondrial oxygen tension decreased to a similar degree as during control exercise (delta 28 ± 10 mmHg; P < 0.05). Conclusion:, Propranolol attenuated the increase in cardiac output of consequence for cerebral perfusion and oxygenation. We suggest that a decrease in cerebral oxygenation limits exercise capacity. [source] Does limb angular motion raise limb arterial pressure?ACTA PHYSIOLOGICA, Issue 3 2009D. D. Sheriff Abstract Aim:, Mechanical factors such as the muscle pump have been proposed to augment flow by several mechanisms. The potential for limb angular motion to augment local perfusion pressure (pressure = ½,r2,2, where , is the fluid density, r the radius and , the angular velocity) has been overlooked. We sought to test the hypothesis that limb angular motion augments limb arterial pressure. Methods:, Nine human subjects performed horizontal shoulder flexion (,±90° at 0.75 Hz for 30 s). We measured finger arterial pressure (photoplethysmography) in the moving (Trial 1) and non-moving arm (Trial 2) in separate trials along with the pressure (strain gauge) generated at the fingers within a length of water-filled tubing mounted on the moving arm in both trials. Results:, Arm swinging raised (P < 0.05) the mean pressure measured in the tubing by 11 ± 2 and 14 ± 2 mmHg (Trials 1 and 2 respectively). In response to exercise, the rise in mean finger arterial pressure in the swinging limb (18 ± 3 mmHg, Trial 1) exceeded (P < 0.05) the rise in the resting limb (8 ± 2 mmHg, Trial 2) by an amount similar to the 11 mmHg rise in pressure generated in the tubing in Trial 1. Conclusions:, We conclude that the swinging of a limb creates centrifugal force (a biomechanical centrifuge) which imparts additional pressure to the arteries, but not the veins owing to the venous valves, which further widens the arterial,venous pressure difference. [source] 5-Hydroxytryptamine-induced microvascular pressure transients in lungs of anaesthetized rabbitsACTA PHYSIOLOGICA, Issue 2 2001N. Sen We determined lung microvascular pressure transients induced by 5-hydroxytryptamine (5HT), by the micropuncture technique. We mechanically ventilated anaesthetized (halothane 0.8%), open-chested rabbits, in which we recorded pulmonary artery (PA), left atrial (LA) and carotid artery pressures and cardiac output. For 4-min periods of stopped ventilation, we constantly inflated the lung with airway pressure of 7 cmH2O, then micropunctured the lung to determine pressures in arterioles and venules of 20,25 ,m diameter. An intravenous bolus infusion of 5HT (100 ,g), increased total pulmonary vascular resistance by 59%. Prior to 5HT infusion, the arterial, microvascular and venous segments comprised 30, 50 and 19% of the total pulmonary vascular pressure drop, respectively. However 14 s after 5HT infusion, the PA-arteriole pressure difference (arterial pressure drop) increased 46%, while the venule-LA pressure difference (venous pressure drop) increased >100%. The arteriole,venule pressure difference (microvascular pressure drop) was abolished. The increase in the arterial pressure drop was maintained for 4.8 min, whereas the increased venous pressure drop reverted to baseline in <1 min. We conclude that in the rabbit lung in situ, a 5HT bolus causes sustained arterial constriction and a strong but transient venous constriction. [source] Expression of the hyaluronan receptor LYVE-1 is not restricted to the lymphatic vasculature; LYVE-1 is also expressed on embryonic blood vesselsDEVELOPMENTAL DYNAMICS, Issue 7 2008Emma J. Gordon Abstract Expression of the hyaluronan receptor LYVE-1 is one of few available criteria used to discriminate lymphatic vessels from blood vessels. Until now, endothelial LYVE-1 expression was reported to be restricted to lymphatic vessels and to lymph node, liver, and spleen sinuses. Here, we provide the first evidence that LYVE-1 is expressed on blood vessels of the yolk sac during mouse embryogenesis. LYVE-1 is ubiquitously expressed in the yolk sac capillary plexus at E9.5, then becomes progressively down-regulated on arterial endothelium during vascular remodelling. LYVE-1 is also expressed on intra-embryonic arterial and venous endothelium at early embryonic stages and on endothelial cells of the lung and endocardium throughout embryogenesis. These findings have important implications for the use of LYVE-1 as a specific marker of the lymphatic vasculature during embryogenesis and neo-lymphangiogenesis. Our data are also the first demonstration, to our knowledge, that the mouse yolk sac is devoid of lymphatic vessels. Developmental Dynamics 237:1901,1909, 2008. © 2008 Wiley-Liss, Inc. [source] Structural and biophysical simulation of angiogenesis and vascular remodeling ,DEVELOPMENTAL DYNAMICS, Issue 4 2001Ralf Gödde Abstract The purpose of this report is to introduce a new computer model for the simulation of microvascular growth and remodeling into arteries and veins that imitates angiogenesis and blood flow in real vascular plexuses. A C++ computer program was developed based on geometric and biophysical initial and boundary conditions. Geometry was defined on a two-dimensional isometric grid by using defined sources and drains and elementary bifurcations that were able to proliferate or to regress under the influence of random and deterministic processes. Biophysics was defined by pressure, flow, and velocity distributions in the network by using the nodal-admittance-matrix-method, and accounting for hemodynamic peculiarities like Fahraeus-Lindqvist effect and exchange with extravascular tissue. The proposed model is the first to simulate interdigitation between the terminal branches of arterial and venous trees. This was achieved by inclusion of vessel regression and anastomosis in the capillary plexus and by remodeling in dependence from hemodynamics. The choice of regulatory properties influences the resulting vascular patterns. The model predicts interdigitating arteriovenous patterning if shear stress-dependent but not pressure-dependent remodeling was applied. By approximating the variability of natural vascular patterns, we hope to better understand homogeneity of transport, spatial distribution of hemodynamic properties and biomass allocation to the vascular wall or blood during development, or during evolution of circulatory systems. © 2001 Wiley-Liss, Inc. [source] Association between plasma osteoprotegerin concentrations and urinary albumin excretion in Type 2 diabetesDIABETIC MEDICINE, Issue 4 2009G. D. Xiang Abstract Aims Osteoprotegerin (OPG) is a recently identified inhibitor of bone resorption. Recent studies indicate that OPG is also associated with endothelial dysfunction in Type 2 diabetes. The aim was to investigate the relationship between plasma OPG levels and urinary albumin excretion (UAE) in Type 2 diabetic patients. Methods This study included 154 newly diagnosed Type 2 diabetic patients and 46 healthy subjects. Plasma OPG and 24-h UAE were measured. High-resolution ultrasound was used to measure flow-mediated (endothelium-dependent arterial) dilation (FMD). Results Compared with the normoalbuminuric subgroup, OPG levels in the microalbuminuric subgroup were significantly higher, and OPG levels in macroalbuminuria subgroup were significantly higher than those in the normoalbuminuria and albuminuria subgroups. Multiple regression analysis showed that only FMD (r = ,0.26), C-reactive protein (r = 0.23), fasting blood glucose (r = 0.25), 2-h blood glucose (r = 0.21), HbA1c (r = 0.28), UAE (r = 0.27) and retinopathy (r = 0.27) were significant factors associated with OPG. Pearson's correlation analyses showed a positive correlation between OPG and logUAE (r = 0.440) and negative correlations between OPG and FMD (r = ,0.284), and between FMD and logUAE (r = ,0.602). Conclusions Plasma OPG levels are significantly associated with UAE in Type 2 diabetic patients. [source] Interstitial glucose in skeletal muscle of diabetic patients during an oral glucose tolerance testDIABETIC MEDICINE, Issue 1 2005M. Frossard Abstract Aim The presence of a transcapillary arterial,interstitial gradient for glucose (AIGglu) in skeletal muscle may be interpreted as a consequence of intact cellular glucose uptake. We hypothesized that the AIGglu decreases in Type 2 diabetes mellitus as a consequence of insulin resistance, whereas it remains intact in Type 1 diabetes. Methods Glucose concentrations were measured in serum and interstitial space fluid of skeletal muscle during an oral glucose tolerance test (OGTT) in patients with Type 1 and Type 2 diabetes and in young and middle-aged healthy volunteers, using microdialysis. Results The area under the curve for glucose in serum (AUCSE) was higher than in interstitial space fluid of skeletal muscle (AUCMU) in healthy young (AUCSE = 1147 ± 332 vs. AUCMU = 633 ± 257 mM/min/ml; P = 0.006), healthy middle-aged volunteers (AUCSE = 1406 ± 186 vs. AUCMU = 1048 ± 229 mM/min/ml; P = 0.001) and in Type 1 diabetic patients (AUCSE = 2273 ± 486 vs. AUCMU = 1655 ± 178 mM/min/ml; P = 0.003). In contrast, in Type 2 diabetic patients AUCSE (2908 ± 1023 mM/min/ml) was not significantly different from AUCMU (2610 ± 722 mM/min/ml; P = NS). Conclusion The present data indicate that AIGglu is compromised in Type 2 diabetes in contrast to Type 1 diabetes where it appears to be normal. Because no changes in muscle blood flow were detected, insulin resistance appears to be the main cause for the observed decreased AIGglu in skeletal muscle in Type 2 diabetic patients. [source] The case for venous rather than arterial blood gases in diabetic ketoacidosisEMERGENCY MEDICINE AUSTRALASIA, Issue 1 2006Anne-Maree Kelly Abstract Objectives:, For patients with diabetic ketoacidosis (DKA), arterial blood gas (BG) sampling for measurement of pH and bicarbonate has been considered an essential part of initial evaluation and monitoring of progress. There is growing evidence that venous values can be clinically acceptable alternatives to arterial measurements. This article summarizes the recent evidence regarding the validity of venous BG sampling in DKA. Methods:, Medline search for the years 1995 to present, hand search of reference lists, search of on-line evidence-based medicine sites. Results:, In patients with DKA the weighted average difference between arterial and venous pH was 0.02 pH units (95% limits of agreement ,0.009 to +0.021 pH units) and between arterial and venous bicarbonate was ,1.88 mEq/L. Conclusions:, There is reasonable evidence that venous and arterial pH have sufficient agreement as to be clinically interchangeable in patients with DKA who are haemodynamically stable and without respiratory failure. There is some evidence that venous and arterial bicarbonate also agree closely in DKA but this requires confirmation. [source] Agreement between bicarbonate measured on arterial and venous blood gasesEMERGENCY MEDICINE AUSTRALASIA, Issue 5-6 2004Anne-Maree Kelly Abstract Objective:, This study aims to determine the extent of agreement between venous and arterial bicarbonate for a group of emergency department patients with respiratory or metabolic illness requiring blood gas analysis as part of their evaluation. Methods:, This prospective study of patients who were deemed by their treating doctor to require an arterial blood gas analysis to determine their ventilatory or acid-base status, compared bicarbonate on an arterial and a venous sample taken as close to simultaneously as possible. Data were analysed using bias (Bland-Altman) methods. Subgroup analyses were performed for the metabolic, respiratory, chronic obstructive airways disease and acidotic subgroups. Results:, Two hundred and forty-six patients were entered into the study; 195 with acute respiratory disease and 51 with suspected metabolic derangement. The values of bicarbonate on arterial and venous samples showed close agreement with an average difference between the samples of 1.20 mmol/L (95% limits of agreement being ,2.73 to +5.13 mmol/L). Similar agreement was found for all subgroups. Conclusion:, Venous bicarbonate estimation shows a high level of agreement with the arterial value, with acceptably narrow 95% limits of agreement. These results suggest that venous bicarbonate estimation may be an acceptable substitute for arterial measurement. [source] Nitric oxide synthase inhibition in Thoroughbred horses augments O2 extraction at rest and submaximal exercise, but not during short-term maximal exerciseEQUINE VETERINARY JOURNAL, Issue S36 2006M. MANOHAR Summary Reason for performing study: Work is required to establish the role of endogenous nitric oxide (NO) in metabolism of resting and exercising horses. Objectives: To examine the effects of NO synthase inhibition on O2 extraction and anaerobic metabolism at rest, and during submaximal and maximal exertion. Methods: Placebo and NO synthase inhibition (with N,-nitro-L-arginine methyl ester [l -NAME] administered at 20 mg/kg bwt i.v.) studies were performed in random order, 7 days apart on 7 healthy, exercise-trained Thoroughbred horses at rest and during incremental exercise leading to 120 sec of maximal exertion at 14 m/sec on a 3.5% uphill grade. Results: At rest, NO synthase inhibition significantly augmented the arterial to mixed-venous blood O2 content gradient and O2 extraction as mixed-venous blood O2 tension and saturation decreased significantly. While NO synthase inhibition did not affect arterial blood-gas tensions in exercising horses, the exercise-induced increment in haemoglobin concentration and arterial O2 content was attenuated. In the l -NAME study, during submaximal exercise, mixed-venous blood O2 tension and haemoglobin-O2 saturation decreased to a greater extent causing O2 extraction to increase significantly. During maximal exertion, arterial hypoxaemia, desaturation of haemoglobin and hypercapnia of a similar magnitude developed in both treatments. Also, the changes in mixed-venous blood O2 tension and haemoglobin-O2 saturation, arterial to mixed-venous blood O2 content gradient, O2 extraction and markers of anaerobic metabolism (lactate and ammonia production, and metabolic acidosis) were not different from those in the placebo study. Conclusion: Endogenous NO production augments O2 extraction at rest and during submaximal exertion, but not the during short-term maximal exercise. Also, NO synthase inhibition does not affect anaerobic metabolism at rest or during exertion. Potential relevance: It is unlikely that endogenous NO release modifies aerobic or anaerobic metabolism in horses performing short-term maximal exertion. [source] Clenbuterol administration does not attenuate the exercise-induced pulmonary arterial, capillary or venous hypertension in strenuously exercising Thoroughbred horsesEQUINE VETERINARY JOURNAL, Issue 6 2000M. MANOHAR Summary The present study was carried out to ascertain whether ,2 -adrenergic receptor stimulation with clenbuterol would attenuate the pulmonary arterial, capillary and venous hypertension in horses performing high-intensity exercise and, in turn, modify the occurrence of exercise-induced pulmonary haemorrhage (EIPH). Experiments were carried out on 6 healthy, sound, exercise-trained Thoroughbred horses. All horses were studied in the control (no medications) and the clenbuterol (0.8 ,g/kg bwt, i.v.) treatments. The sequence of these treatments was randomised for every horse, and 7 days were allowed between them. Using catheter-tip-transducers whose in-vivo signals were referenced at the point of the left shoulder, right heart/pulmonary vascular pressures were determined at rest, sub-maximal exercise and during galloping at 14.2 m/s on a 3.5% uphill grade - a workload that elicited maximal heart rate and induced EIPH in all horses. In the control experiments, incremental exercise resulted in progressive significant increments in right atrial as well as pulmonary arterial, capillary and venous (wedge) pressures and all horses experienced EIPH. Clenbuterol administration to standing horses caused tachycardia, but significant changes in mean right atrial or pulmonary vascular pressures were not observed. During exercise performed after clenbuterol administration, heart rate as well as right atrial and pulmonary arterial, capillary and wedge pressures also increased progressively with increasing work intensity. However, these values were not found to be statistically significantly different from corresponding data in the control study and the incidence of EIPH remained unaffected. Since clenbuterol administration also does not affect the transpulmonary pressure during exercise, it is unlikely that the transmural force exerted onto the blood-gas barrier of exercising horses is altered following i.v. clenbuterol administration at the recommended dosage. [source] Arterial stiffness in relation to subclinical atherosclerosisEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 1 2009A. Wykretowicz ABSTRACT Background, Increased arterial stiffness or arteriosclerosis, represents a physiological part of ageing. Atherosclerosis is a process that does not affect the arterial bed uniformly but has a variable local distribution and is frequently superimposed on stiffened vessels. We therefore addressed the question of whether any correlation exists between the general characteristics of arterial stiffness or wave reflection and subclinical atherosclerosis as assessed by carotid intima-media thickness (IMT) in a sample of healthy subjects. Methods, A total of 116 healthy subjects (mean age 55 years, 43 female) were evaluated. Arterial stiffness and wave reflection was assessed with the use of digital volume pulse analysis (DVP) and pulse wave analysis (PWA). Subclinical atherosclerosis was assessed by measurement of IMT. Results, Stiffness Index (SIDVP), the measure of general arterial stiffness correlated significantly with IMT (r = 0·37, P < 0·01). IMT correlated significantly with age (r = 0·5, P < 0·0001), waist to hip ratio (WHR) (r = 0·39, P < 0·0001) and mean blood pressure (BPmean) (r = 0·4, P < 0·0001). IMT did not correlate with measures of wave reflection. SIDVP correlated significantly with age (r = 0·32, P < 0·005), WHR (r = 0·36, P < 0·0001), BPmean (r = 0·36, P < 0·0001) and measurements of wave reflection. However analysis of a model which included variables that significantly influenced SIDVP and IMT, such as age, WHR and mean BP showed that arterial stiffness is not independently associated with subclinical atherosclerosis. Conclusions, The indices of subclinical atherosclerosis, arterial stiffness and wave reflection, indicate different aspects of vascular status in otherwise healthy subjects [source] Neuronal and vascular localization of histamine N-methyltransferase in the bovine central nervous systemEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2000Masahiro Nishibori Abstract Histamine N-methyltransferase (HMT) (EC 2.1.1.8) plays a crucial role in the inactivation of the neurotransmitter histamine in the CNS. However, the localization of HMT remains to be determined. In the present study, we investigated immunohistochemical localization of HMT in the bovine CNS using a polyclonal antibody against bovine HMT. The HMT-like immunoreactivity was observed mainly in neurons. Strongly immunoreactive neurons were present in the oculomotor nucleus and ruber nucleus in the midbrain, the facial nucleus in the pons, the dorsal vagal nucleus and hypoglossal nucleus in the medulla oblongata and in the anterior horn as well as intermediolateral zone of the spinal cord. Intermediately immunoreactive neurons were present in the piriform cortex and the inferior olivary nucleus. The grey matter of the forebrain regions was diffusely and faintly stained. In the cerebellum and the striatum, the nerve fibres in the white matter were positive. The tuberomammillary nucleus, where histaminergic neurons are present, were weakly positive. The other immunoreactive structures in the CNS were blood vessels. Almost all of the blood vessel walls, irrespective of whether they were arterial or venous, were variably stained. The glial fibrillary acidic protein- (GFAP-) immunoreactive astrocytes were not stained. These findings indicated that histamine released from histaminergic nerve terminals or varicose fibres is methylated mainly in postsynaptic or extrasynaptic neurons rather than in astrocytes. The localization of HMT in the blood vessel wall may mean that blood-borne histamine and histamine released from mast cells associated with the blood vessels are catabolized in this structure. [source] Organ-specific ligation-induced changes in harmonic components of the pulse spectrum and regional vasoconstrictor selectivity in Wistar ratsEXPERIMENTAL PHYSIOLOGY, Issue 1 2006Tse Lin Hsu It has been shown previously that the amplitudes of the harmonic components of the pulse spectrum vary in specific patterns when the arteries leading to different organs are ligated, with the variations in the harmonics being linearly additive. Since ligation can be regarded as a vast increase in organ resistance, the present study examined the potential of using these ligation-induced variations in the pulse spectrum as reference parameters for an increase in vascular resistance and for regional vasoconstrictor selectivity. A vasoconstrictor, either arginine vasopressin (AVP) or angiotensin II (Ang II), was infused into anaesthetized Wistar rats via the femoral vein for 1 h. The distinct harmonic-specific drug effects on the pulse spectrum were simulated by combining renal artery and superior mesenteric artery ligations in different ratios, the ratio with the lowest mean square difference determining the regional drug selectivity. The ratios indicated that the effect of AVP on the pulse spectrum was attributable to the combined effect of ligating the renal and superior mesenteric arteries, while the effect of Ang II was attributable to ligation of the renal artery. The results are comparable with those of investigations of regional vascular resistance performed using traditional methods. Our findings indicate that the ligation-induced variations in the pulse spectrum can be used to determine regional increases in vascular resistance. This implies that blood pressure can be used as the sole parameter to determine which arterial bed has been affected by the vasoconstrictor, and how seriously. [source] Combined neural network model to compute wavelet coefficientsEXPERT SYSTEMS, Issue 3 2006nan Güler Abstract: In recent years a novel model based on artificial neural networks technology has been introduced in the signal processing community for modelling the signals under study. The wavelet coefficients characterize the behaviour of the signal and computation of the wavelet coefficients is particularly important for recognition and diagnostic purposes. Therefore, we dealt with wavelet decomposition of time-varying biomedical signals. In the present study, we propose a new approach that takes advantage of combined neural network (CNN) models to compute the wavelet coefficients. The computation was provided and expressed by applying the CNNs to ophthalmic arterial and internal carotid arterial Doppler signals. The results were consistent with theoretical analysis and showed good promise for discrete wavelet transform of the time-varying biomedical signals. Since the proposed CNNs have high performance and require no complicated mathematical functions of the discrete wavelet transform, they were found to be effective for the computation of wavelet coefficients. [source] Urgent arterial: venous fistula to secure vascular access in a patient with severe factor V deficiency and intracranial haemorrhageHAEMOPHILIA, Issue 4 2007L. PEAKE No abstract is available for this article. [source] | |||||||||||||||||||||||||||||||||||||||||||