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Kinds of Pressure Decreased Selected AbstractsPlasma IL-6 concentration is inversely related to insulin sensitivity, and acute-phase proteins associate with glucose and lipid metabolism in healthy subjectsDIABETES OBESITY & METABOLISM, Issue 6 2005M. K. Heliövaara Aim:, It has been shown that atherosclerosis is an inflammatory disease. Recent data suggest that inflammation precedes type 2 diabetes. Hence, we wanted to study the interrelationship between IL-6, insulin sensitivity, lipids and numerous acute-phase proteins. Methods:, Twenty-one healthy individuals [16 males/5 females, age 27.9 ± 1.8 years, body mass index (BMI) 24.1 ± 0.8 kg/m2] participated in the study. Each patient went through a 4-h hyperinsulinaemic (40 mU/m2/min) euglycaemic clamp and 4-h saline infusion. Blood samples were taken before and at the end of the infusions. Results:, Plasma interleukin (IL)-6 concentration correlated inversely with insulin sensitivity (M -value) (r = ,0.49, p < 0.05). Moreover, the plasma levels of IL-6 associated with c-peptide (r = 0.49, p < 0.05), fat% (r = 0.43, p < 0.05) and diastolic blood pressure (r = 0.46, p < 0.05). ,-1-acid glycoprotein was related to HbA1c (r = 0.47, p < 0.05), insulin (r = 0.55, p < 0.01), diastolic blood pressure (r = 0.58, p < 0.01), systolic blood pressure (r = 0.58, p < 0.01) and triglycerides (r = 0.58, p < 0.01). Haptoglobin was correlated with insulin (r = 0.46, p < 0.05), total cholesterol (r = 0.61, p < 0.01), BMI (r = 0.58, p < 0.01), fat% (r = 0.63, p < 0.01) and lipid oxidation during clamp (r = 0.43, p < 0.05). Diastolic blood pressure decreased during the clamp (from 78.3 ± 1.9 to 72.1 ± 2.0 mmHg, p = 0.001). Insulin infusion did not affect the serum levels of most acute-phase proteins. Conclusions:, Our study suggests that low grade inflammation, as reflected by IL-6, A1GP and haptoglobin contributes to the regulation of insulin sensitivity, lipid metabolism and blood pressure in normal human physiology. [source] Rosiglitazone improves insulin sensitivity, glucose tolerance and ambulatory blood pressure in subjects with impaired glucose toleranceDIABETIC MEDICINE, Issue 5 2004S. M. A. Bennett Abstract Aims To determine the effects of rosiglitazone on insulin sensitivity, glucose tolerance and ambulatory blood pressure when administered to subjects with persistent impaired glucose tolerance (IGT). Methods Eighteen subjects with persistent IGT were randomized to receive rosiglitazone 4 mg twice daily or matching placebo for 12 weeks. Evaluation at baseline and at the end of treatment included measurement of whole body insulin sensitivity during a euglycaemic hyperinsulinaemic clamp and deriving an insulin sensitivity index. Changes in glucose and insulin concentration were determined after oral glucose tolerance test (OGTT) and mixed meal tolerance tests, and 24-h ambulatory blood pressure was monitored. Results Rosiglitazone significantly improved the insulin sensitivity index by 2.26 µg/kg per min per pmol/l relative to placebo (P = 0.0003). Four of nine subjects receiving rosiglitazone reverted to normal glucose tolerance and 5/9 remained IGT, although four of these had improved 2-h glucose values. In the placebo group, 1/9 subjects progressed to Type 2 diabetes and 8/9 remained IGT. Following OGTT and meal tolerance test, glucose and insulin area under curve were reduced over 3 and 4 h, respectively. Compared with placebo, ambulatory blood pressure decreased significantly in the rosiglitazone group by 10 mmHg systolic (P = 0.0066) and 8 mmHg diastolic (P = 0.0126). Conclusions Consistent with its effects in patients with Type 2 diabetes, rosiglitazone substantially improved whole body insulin sensitivity and the glycaemic and insulinaemic responses to an OGTT and meal tolerance test in subjects with persistent IGT. Furthermore, rosiglitazone reduced systolic and diastolic ambulatory blood pressure in these subjects. [source] Long-term follow-up of achalasic patients treated with botulinum toxinDISEASES OF THE ESOPHAGUS, Issue 2 2000D'Onofrio Botulinum toxin A (BoTx), a potent inhibitor of acetylcholine release from nerve endings both within the myenteric plexus and at the nerve,muscle junction, has been shown to decrease the lower esophageal sphincter (LES) pressure in patients with achalasia. Because of this property, the esophageal injection of BoTx has been suggested as an alternative treatment in achalasia. The objective of this study was to determine the long-term efficacy and safety of intrasphincteric injection of BoTx in a group of achalasic patients. Nineteen patients (mean age 56.1 ± 19.2 years) were enrolled in the study. All of them were injected endoscopically with 100 U of BoTx by sclerotherapy needle at different sites of the LES. Symptom score (dysphagia, regurgitation and chest pain, each on a 0,3 scale), esophageal manometer and esophageal radionuclide emptying were assessed before the treatment and at 4 weeks, 3 months and 1 year after BoTx injection. In case of failure or relapse (symptom score >2), the treatment was repeated. All but five patients (74%) were in clinical remission at 1 month. Mean symptom score after 1 month of BoTx decreased from 7.1 ± 0.9 to 2.2 ± 2.5 (p < 0.05). LES pressure decreased from 38.4 ± 13.7 to 27.4 ± 13.5 mmHg (p < 0.05) and 10-min radionuclide retention decreased from 70.9 ± 20.7% to 33.8 ± 27.0% (p < 0.05). Side-effects (transient chest pain) were mild and infrequent. At 12 months, the clinical score was 0.9 ± 0.5 (p < 0.05 vs. basal); mean LES pressure was 22.0 ± 7.1 (p < 0.05 vs. basal) and 10-min radionuclide retention was 15.8 ± 6.0% (p < 0.05 vs. basal). The efficacy of the first injection of BoTx lasted for a mean period of 9 months (range 2,14 months). At the time of writing (follow-up period mean 17.6 months, range 2,31), 14 patients (10 with one injection) were still in remission (74%). Our results showed that one or two intrasphincteric injections of BoTx resulted in clinical and objective improvement in about 74% of achalasic patients and are not associated with serious adverse effects; the efficacy of BoTx treatment was long lasting; this procedure could be considered an attractive treatment, especially in elderly patients who are poor candidates for more invasive procedures. [source] Controls on englacial sediment deposition during the November 1996 jökulhlaup, Skei,arįrjökull, IcelandEARTH SURFACE PROCESSES AND LANDFORMS, Issue 9 2001Matthew J. Roberts Abstract This paper presents sedimentary evidence for rapid englacial debris entrainment during jökulhlaups. Previous studies of jökulhlaup sedimentology have focused predominantly on proglacial impact, rather than depositional processes within glaciers. However, observations of supraglacial floodwater outbursts suggest that englacial sediment emplacement is possible during jökulhlaups. The November 1996 jökulhlaup from Skei,arįrjökull, Iceland presented one of the first opportunities to examine englacial flood deposits in relation to former supraglacial outlets. Using observations from Skei,arįrjökull, this paper identifies and explains controls on the deposition of englacial flood sediments and presents a qualitative model for englacial jökulhlaup deposition. Englacial jökulhlaup deposits were contained within complex networks of upglacier-dipping fractures. Simultaneous englacial deposition of fines and boulder-sized sediment demonstrates that englacial fracture discharge had a high transport capacity. Fracture geometry was an important control on the architecture of englacial jökulhlaup deposits. The occurrence of pervasively frozen flood deposits within Skei,arįrjökull is attributed to freeze-on by glaciohydraulic supercooling. Floodwater, flowing subglacially or through upglacier-dipping fractures, would have supercooled as it was raised to the surface faster than its pressure-melting point could increase as glaciostatic pressure decreased. Evidence for floodwater contact with the glacier bed is supported by the ubiquitous occurrence of sheared diamict rip-ups and intra-clasts of basal ice within jökulhlaup fractures, deposited englacially some 200,350 m above the bed of Skei,arįrjökull. Evidence for fluidal supercooled sediment accretion is apparent within stratified sands, deposited englacially at exceptionally high angles of rest in the absence of post-depositional disturbance. Such primary sediment structures cannot be explained unless sediment is progressively accreted to opposing fracture walls. Ice retreat from areas of former supraglacial outbursts revealed distinct ridges characterized by localized upwellings of sediment-rich floodwater. These deposits are an important addition to current models of englacial sedimentation and demonstrate the potential for post-jökulhlaup landform development. Copyright © 2001 John Wiley & Sons, Ltd. [source] Comparison of in vivo effects of nitroglycerin and insulin on the aortic pressure waveformEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 1 2004J. Westerbacka Abstract Background, Individuals whose platelets are resistant to the antiaggregatory effects of insulin in vitro are also resistant to the antiaggregatory effects of nitroglycerin (GTN). We have previously shown that insulin acutely diminishes central wave reflection in large arteries and that this action of insulin is blunted in insulin-resistant subjects. However, as yet, no studies have compared the haemodynamic effects of insulin and GTN on large arterial function in the same group of subjects. The aim of this study was to determine whether resistance to the haemodynamic effects of insulin is a defect specific to insulin or whether individuals resistant to the vascular actions of insulin are also resistant to GTN. Design and results, Dose,response characteristics of insulin and GTN on the aortic waveform were determined using applanation tonometry and pulse wave analysis (PWA) in seven healthy men (age 26 ± 1 year, BMI 25 ± 2 kg m,2). Three doses of sublingual GTN (500 µg for 1, 3 or 5 min) and insulin (0·5, 1 or 2 mU kg,1 min,1 for 120 min) were administered on three separate occasions. Both agents dose-dependently decreased central pulse pressure and the augmentation index (AIx) without changing brachial artery blood pressure. We next compared responses to insulin (2 mU kg,1 min,1 for 120 min) and sublingual GTN (500 µg for 5 min) in 20 nondiabetic subjects (age 50 ± 2 year, BMI 21·0,36·3 kg m,2). Again, both agents significantly decreased AIx. Although the vascular effects of insulin and GTN vascular were positively correlated [Spearman's r = 0·92 (95% confidence interval 0·81,0·97), P < 0·0001], the time-course for the action GTN was faster than that of insulin. Brachial systolic blood pressure remained unchanged during the insulin infusion (122 ± 3 vs. 121 ± 3 mmHg, 0 vs. 120 min) but aortic systolic blood pressure decreased significantly by 30 min (111 ± 3 vs. 107 ± 3 mmHg, 0 vs. 30 min, P < 0·01). Similarly, GTN decreased aortic systolic blood pressure from 119 ± 4 to maximally 112 ± 3 mmHg (P < 0·001) without significantly decreasing systolic blood pressure in the brachial artery. Conclusions, The effects of insulin and GTN on large arterial haemodynamics are dose-dependent and significantly correlated. The exact mechanisms and sites of action of insulin and GTN in subjects with insulin resistance remain to be established. [source] Modulation of systemic and renal haemodynamics by ,-opioids in conscious lambsEXPERIMENTAL PHYSIOLOGY, Issue 5 2006Wei Qi The purpose of the present study was to determine the cardiovascular effects of the ,-opioid receptor agonist U-50488H at two stages of postnatal maturation under physiological conditions. Experiments were carried out firstly to define systemic and renal haemodynamic responses to ,-opioid receptor activation and, secondly, to determine whether these effects are altered during postnatal maturation. To investigate whether the responses to U-50488H resulted from receptor-dependent effects, responses to U-50488H were also tested in the presence of the specific ,-opioid receptor antagonist 5,-guanidinonaltrindole (GNTI). Experiments were carried out in two groups of conscious, chronically instrumented lambs aged ,1 and ,6 weeks. Mean arterial pressure, mean venous pressure and renal blood flow (RBF) were measured for 30 min before and 90 min after i.v. injection of U-50488H or vehicle. Heart rate increased in both age groups of lambs within 10 min of U-50488H administration. Mean arterial pressure decreased for 50 min following U-50488H administration at 1 week but, in contrast, increased transiently at 10 min in 6-week-old lambs, returning to control levels by 20 min. In both age groups, there was a sustained decrease in RBF following U-50488H. The aforementioned responses to U-50488H were abolished by pretreatment with GNTI. These data provide the first measurements of systemic and renal haemodynamic responses to ,-opioid receptor activation during postnatal maturation. [source] Improvement in "uremic" cardiomyopathy by persistent ultrafiltrationHEMODIALYSIS INTERNATIONAL, Issue 1 2007Hüseyin TÖZ Abstract Some patients with end-stage renal disease suffer severe cardiac dilatation with functional disturbances, notably low ejection fraction (EF) and valvular regurgitation. They often have normal or low blood pressure, and tolerate ultrafiltration (UF) poorly. The aim of our study was to investigate to what extent this condition can still be improved by persistent slow UF. Twelve patients with cardiothoracic index >0.54 and EF <0.45 but otherwise uncomplicated were treated by slow, prolonged UF during hemodialysis (3 times a week) sessions, if necessary supplemented by isolated UF sessions on a separate day. Repeated chest X-rays and Doppler echocardiography were applied. During treatment periods varying from 20 to 120 days, all of the patients lost weight (12±10 kg) and became edema free. Cardiothoracic index decreased in all patients from a mean of 0.59±0.04 to 0.47±0.03. Blood pressure decreased when it had been elevated and increased when it was below normal. Ejection fraction increased in all of them from a mean of 0.31±0.9 to 0.50±0.9. Mitral and tricuspid regurgitation were found in every patient and disappeared or improved in all of them. Striking improvement of cardiac dilatation and dysfunction can be achieved by carefully monitored persistent UF in the majority of patients with seemingly intractable dilated cardiomyopathy. [source] Nocturnal Hemodialysis Is Better Than Quotidian HemodialysisHEMODIALYSIS INTERNATIONAL, Issue 1 2003MP Kooistra Background. It is unknown whether long nocturnal (6,7 times weekly 6,8 hours) hemodialysis (NHD) is better than frequent short hemodialysis (,daily', quotidian hemodialysis, QHD). Methods. A Dutch NHD pilot study (,Nocturne') started in December 2001. We can now evaluate effects of 4 months NHD in 14 patients. Baseline dialysis frequency was 3.5 or less (3.13 ± 0.23, M ± SD) in group A (n = 8), and 4 or more (5.0 ± 0.89) in group B (n = 6), weekly dialysis time was equal in both groups. Results. Single pool Kt/V, being higher in group B at baseline, increased in both groups (A: 3.1 ± 0.8/week to 9.5 ± 2.3, B: 3.8 ± 1.0 to 10.9 ± 4.1). Baseline nPCR, being higher in group B, increased in both groups (A: 1.0 ± 0.3 g/kg/week to 1.4 ± 0.3, and B: 1.2 ± 0.5 to 1.8 ± 0.5). Baseline albumin was higher in group B, and increased in group A (39.6 ± 3.7 g/l to 43.2 ± 1.5), not in B (41.4 ± 2.3 to 42.8 ± 2.3). Target weight increased only in group A (71.8 ± 10.5 kg to 75.3 ± 11.9), not in B (71.4 ± 25.5 to 71.3 ± 26.7). NHD resulted in normophosphatemia in both groups despite phosphate supplementation and cessation of phosphate binders. PTH decreased in both groups (A: 40.6 ± 38.0 pmol/l to 14.4 ± 11.7, B: 35.6 ± 37.7 to 22.4 ± 41.5). In both groups, pre- and postdialysis mean arterial pressure decreased (A: 106.8 ± 7.9 mmHg to 94.4 ± 12.1 and 97.3 ± 9.5 mmHg to 86.3 ± 8.2, B: 102.2 ± 28.4 to 89.4 ± 9.5 and 90.3 ± 26.8 to 82.7 ± 12.9). Antihypertensives were discontinued or markedly reduced. Fatigue, insomnia, prurigo, restlessness, appetite, physical condition, working ability and quality of life (SF36) improved significantly in both groups. Conclusion. This small pilot study suggests that phosphate and PTH control, blood pressure, uremic symptoms and quality of life improve when conventional hemodialysis or QHD patients switch to NHD. Nutritional parameters improve only in the previously conventionally treated group. [source] Body positions and esophageal sphincter pressures in obese patients during anesthesiaACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 4 2010A. DE LEON Background: The lower esophageal sphincter (LES) and the upper esophageal sphincter (UES) play a central role in preventing regurgitation and aspiration. The aim of the present study was to evaluate the UES, LES and barrier pressures (BP) in obese patients before and during anesthesia in different body positions. Methods: Using high-resolution solid-state manometry, we studied 17 patients (27,63 years) with a BMI,35 kg/m2 who were undergoing a laparoscopic bariatric surgery before and after anesthesia induction. Before anesthesia, the subjects were placed in the supine position, in the reverse Trendelenburg position (+20°) and in the Trendelenburg position (,20°). Thereafter, anesthesia was induced with remifentanil and propofol and maintained with remifentanil and sevoflurane, and the recordings in the different positions were repeated. Results: Before anesthesia, there were no differences in UES pressure in the different positions but compared with the other positions, it increased during the reverse Trendelenburg during anesthesia. LES pressure decreased in all body positions during anesthesia. The LES pressure increased during the Trendelenburg position before but not during anesthesia. The BP remained positive in all body positions both before and during anesthesia. Conclusion: LES pressure increased during the Trendelenburg position before anesthesia. This effect was abolished during anesthesia. LES and BPs decreased during anesthesia but remained positive in all patients regardless of the body position. [source] Influence of hypertension on lower urinary tract symptoms in benign prostatic hyperplasiaINTERNATIONAL JOURNAL OF UROLOGY, Issue 11 2003KIMIO SUGAYA Abstract Aim:, To clarify the influence of hypertension on lower urinary tract symptoms (LUTS) we examined the relationship between blood pressure, LUTS, and the effect of terazosin on LUTS in patients with benign prostatic hyperplasia (BPH). Methods:, The subjects were patients who had LUTS and BPH. They were treated with terazosin (1 mg, twice-a-day) for 12 weeks. Calculation of the International Prostate Symptom Score (IPSS), measurement of blood pressure, and uroflowmetry were performed before and after 12 weeks of therapy. Patients were divided into a normotensive (NT) group and a hypertensive (HT) group at the time of first examination. Results:, The IPSS for urinary frequency and nocturia in BPH-HT patients (n = 21; mean age, 71 years) were significantly higher than those in the BPH-NT patients (n = 21; mean age, 69 years) before the administration of terazosin. The total IPSS the BPH-HT patients was also significantly higher than that of the BPH-NT patients. There were no differences of uroflowmetric parameters between the two groups. After 12 weeks of therapy, systolic and diastolic blood pressure decreased in the BPH-HT patients, but not in the BPH-NT patients. However, the systolic pressure of the BPH-HT patients was still significantly higher than that of the BPH-NT patients. The score for each IPSS parameter decreased in both groups, but the difference of the score between the two groups increased. Conclusion:, Hypertension may worsen LUTS and may decrease the improvement of symptoms by terazosin. [source] Dietary Approaches to Stop Hypertension (DASH) diet: applicability and acceptability to a UK populationJOURNAL OF HUMAN NUTRITION & DIETETICS, Issue 1 2010K. E. Harnden Abstract Background:, The Dietary Approaches to Stop Hypertension (DASH) diet is widely promoted in the USA for the prevention and treatment of high blood pressure. It is high in fruit and vegetables, low-fat dairy and wholegrain foods and low in saturated fat and refined sugar. To our knowledge, the use of this dietary pattern has not been assessed in a free-living UK population. Methods:, The DASH diet was adapted to fit UK food preferences and portion sizes. Fourteen healthy subjects followed the adapted DASH diet for 30 days in which they self-selected all food and beverages. Dietary intake was assessed by 5-day food diaries completed before and towards the end of the study. Blood pressure was measured at the beginning and end of the study to assess compliance to the DASH style diet. Results:, The DASH diet was easily adapted to fit with UK food preferences. Furthermore, it was well tolerated and accepted by subjects. When on the DASH style diet, subjects reported consuming significantly (P < 0.01) more carbohydrate and protein and less total fat (5%, 6% and 9% total energy, respectively). Sodium intakes decreased by 860 mg day,1 (P < 0.001). Systolic and diastolic blood pressure decreased significantly (P < 0.05) by 4.6 and 3.9 mmHg, respectively when on the DASH style diet. Conclusions:, The DASH style diet was well accepted and was associated with a decrease in blood pressure in normotensive individuals and should be considered when giving dietary advice to people with elevated blood pressure in the UK. [source] Different bispectral index values from both sides of the forehead in unilateral carotid artery stenosisACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 1 2009E. H. LEE Bispectral index (BIS) values derived from the left and right forehead are usually the same. We report on two patients with unilateral carotid artery stenosis in whom we observed differences between the BIS values obtained from sensors placed on each side of the forehead. During surgery, the BIS values of the diseased side decreased more than those of the opposite side when the mean arterial pressure decreased below 70 mmHg. BIS monitors should be used with caution in patients with unilateral carotid artery and cerebrovascular disease. [source] Effect of delayed supine positioning after induction of spinal anaesthesia for caesarean sectionACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 4 2002F. Kųhler Background: The study tested the hypothesis that the incidence of hypotension during spinal anaesthesia for caesarean section is less in parturients who remain in the sitting position for 3 min compared with parturients who are placed in the modified supine position immediately after induction of spinal anesthesia. Methods: Spinal anaesthesia was induced with the woman in the sitting position using 2.8 ml hyperbaric bupivacaine 0.5% at the L3,4 or L2,3 interspace. Ninety-eight patients scheduled for elective caesarean section under spinal anaesthesia were randomised to assume the supine position on an operating table tilted 10° to the left (modified supine position) immediately after spinal injection (group 0, n=52) or to remain in the sitting position for 3 min before they also assumed the modified supine position (group 3, n=46). Isotonic saline 2,300 ml was given intravenously over 15 min before spinal injection followed by 15 ml/kg over 15,20 min after induction of spinal anaesthesia. If the systolic blood pressure decreased to less than 70% of baseline or to less than 100 mmHg or if there was any complaint of nausea, ephedrine was given in 5 mg boluses intravenously every 2 min. Results: The blood pressure decreased significantly in both groups following spinal injection (P<0.001). Blood pressure variations over time differed significantly between the two groups (P<0.05). However, the incidence of maternal hypotension before delivery was similar in the two groups. The difference was caused by the time to the blood pressure nadir being significantly shorter in group 0 compared with group 3 (9.1±4.5 min vs. 11.7±3.7 min, P<0.01). Similar numbers of patients received rescue with ephedrine before delivery: 35 (67%) in group 0 vs. 26 (57%) in group 3 (NS). The mean total dose of ephedrine before delivery was 10.9 mg in group 0 vs. 9.2 mg in group 3 (NS). There were no differences in neonatal outcome between the two groups. Conclusion: At elective caesarean section, a 3-min delay before supine positioning does not influence the incidence of maternal hypotension after induction of spinal anaesthesia in the sitting position with 2.8 ml of bupivacaine 0.5% with 8% dextrose. [source] During hypoxic exercise some vasoconstriction is needed to match O2 delivery with O2 demand at the microcirculatory levelTHE JOURNAL OF PHYSIOLOGY, Issue 1 2008Carsten Lundby To test the hypothesis that the increased sympathetic tonus elicited by chronic hypoxia is needed to match O2 delivery with O2 demand at the microvascular level eight male subjects were investigated at 4559 m altitude during maximal exercise with and without infusion of ATP (80 ,g (kg body mass),1 min,1) into the right femoral artery. Compared to sea level peak leg vascular conductance was reduced by 39% at altitude. However, the infusion of ATP at altitude did not alter femoral vein blood flow (7.6 ± 1.0 versus 7.9 ± 1.0 l min,1) and femoral arterial oxygen delivery (1.2 ± 0.2 versus 1.3 ± 0.2 l min,1; control and ATP, respectively). Despite the fact that with ATP mean arterial blood pressure decreased (106.9 ± 14.2 versus 83.3 ± 16.0 mmHg, P < 0.05), peak cardiac output remained unchanged. Arterial oxygen extraction fraction was reduced from 85.9 ± 5.3 to 72.0 ± 10.2% (P < 0.05), and the corresponding venous O2 content was increased from 25.5 ± 10.0 to 46.3 ± 18.5 ml l,1 (control and ATP, respectively, P < 0.05). With ATP, leg arterial,venous O2 difference was decreased (P < 0.05) from 139.3 ± 9.0 to 116.9 ± 8.4,1 and leg was 20% lower compared to the control trial (1.1 ± 0.2 versus 0.9 ± 0.1 l min,1) (P= 0.069). In summary, at altitude, some degree of vasoconstriction is needed to match O2 delivery with O2 demand. Peak cardiac output at altitude is not limited by excessive mean arterial pressure. Exercising leg is not limited by restricted vasodilatation in the altitude-acclimatized human. [source] Exercise Training During Hemodialysis Reduces Blood Pressure and Increases Physical Functioning and Quality of LifeARTIFICIAL ORGANS, Issue 7 2010Maycon De Moura Reboredo Abstract Hypertension and cardiovascular diseases are highly prevalent in hemodialysis patients and are associated with the reduction of physical functioning and quality of life. We evaluated the effects of supervised aerobic exercise training on physical functioning, blood pressure, quality of life, and laboratory data in hemodialysis patients. Fourteen patients were evaluated at the beginning and after 12 weeks of stretching exercises (control phase) and at the end of 12 weeks of aerobic exercise training performed during hemodialysis sessions (intervention phase). Patients underwent a 6-min walking test (6MWT), 24-h ambulatory blood pressure monitoring, a Medical Outcomes Study 36,Item Short-Form Health Survey (SF-36) quality of life questionnaire, and blood sample collections. After the intervention phase, the 6MWT distance increased from 508.7 ± 91.9 m to 554.9 ± 105.8 m (P = 0.001), systolic and diastolic blood pressure decreased respectively from 150.6 ± 18.4 mm Hg to 143.5 ± 14.7 mm Hg and from 94.6 ± 10.5 mm Hg to 91.4 ± 9.7 mm Hg (P < 0.05), while hemoglobin levels increased from 10.8 ± 1.2 g/dL to 11.6 ± 0.8 g/dL (P < 0.05). Moreover, there was a significant increase in the physical functioning, social functioning, and mental health dimensions of the SF-36. Aerobic exercise training during hemodialysis increased physical functioning, reduced blood pressure levels, and improved the control of anemia and quality of life in patients with end-stage renal disease. [source] Effects of Left Ventricular Assist Device on Cardiac Function: Experimental Study of Relationship between Pump Flow and Left Ventricular Diastolic FunctionARTIFICIAL ORGANS, Issue 9 2001Akira Saito Abstract: The left ventricular assist device (LVAD) with centrifugal pump has two characteristics. One is a pump flow wave of the centrifugal pump, consisting of the pulsatile flow of the native heart and the nonpulsatile flow of the centrifugal pump. The other is that the centrifugal pump fills from the native heart not only in the systolic phase, but also in the diastolic phase. In the case of the apex outlet LVAD with centrifugal pump, blood flows from the left atrium through the left ventricle to the pump. Pump flow is regulated by preload, and preload is regulated by diastolic hemodynamics. The aim of this study is to analyze the relationship between pump flow and the diastolic hemodynamics of the native heart. Ten anesthetized intact pigs were studied after placement of an LVAD. Data were recorded with the LVAD off (control) and the LVAD on. The assist rate was changed to 25%, 50%, and 75%. The indexes of left ventricular (LV) diastolic function included LV myocardial relaxation (time constant of isovolumic pressure decay [Tau] and maximum negative dP/dt[LV dP/dt min]) and LV filling (peak filling rate [PFR], time to peak filling rate [tPFR], and diastolic filling time [DFT]). Stroke volume decreased significantly in 75% assist. LV end-systolic pressure decreased significantly in 50% and 75% assist. LV end-diastolic volume decreased as assist rate increased, but there were no significant changes. Stroke work decreased significantly in 50% and 75% assist. LV dP/dt min decreased significantly in 50% and 75% assist. Tau prolonged as assist rate increased, but there were no significant changes. DFT shortened significantly in 75% assist. PFR increased significantly in 75% assist. tPFR shortened significantly in 50% and 75% assist. In this study, LV relaxation delayed as an increasing of pump assist rate, but it suggested a result of reduction of cardiac work. Also, it was suggested that LVAD increases the pressure difference between the left atrium and the left ventricle in the diastolic phase. This phenomenon is due to the filling of the left ventricle. In this study it was suggested that as pump assist rate increases, it is more effective to keep cardiac function in the diastolic phase. [source] Broth conditions determining specific cake resistance during microfiltration of Bacillus subtilisBIOTECHNOLOGY & BIOENGINEERING, Issue 2 2006Kevin Graves Abstract The effects of broth pH, pressure, temperature, and fermentation medium on specific cake resistance were studied for dead-end microfiltration of Bacillus subtilis. Decreases in pH and transmembrane pressure decreased the specific cake resistance for cells grown in both complex and defined media. With the complex medium, the reduction in resistance with temperature decrease did not offset the flux decrease caused by the increase in viscosity. The greatest decrease in specific cake resistance occurred with adjustment of pH to 7.5 for cells grown in defined medium. For those cells the change in pH resulted in aggregation leading to a large increase in flux. © 2006 Wiley Periodicals, Inc. [source] Cross sectional study of automated blood pressure measurements throughout pregnancyBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 4 2004N. Ochsenbein-Kölble Objective To generate reliable new reference ranges for pregnancy blood pressure from a large population. Design A prospective cross sectional study. Setting Obstetric outpatient clinic, Zurich University Hospital. Sample Accurately dateable singleton pregnancies (Caucasian: n= 3234; Asian [predominantly from Sri Lanka, Thailand and the Philippines]: n= 577; Black n= 212). Methods Between January 1996 and February 2000 blood pressure was determined in 4023 pregnant women using an oscillometric automated device (Dinamap) according to British Hypertension Society recommendations. Women receiving antihypertensive medication were excluded. Main outcome measure Blood pressure. Results Only the means of duplicate measures at the booking visit (5,42 weeks) were used in the analysis. Mean blood pressure decreased from early to mid pregnancy before increasing to levels 4 mmHg higher at term than in early pregnancy. Values >130/80 and <90/50 mmHg were above the 95th and below the 5th centiles, respectively. Parity, age and body mass index were significant determinants in Caucasians. Blood pressure was slightly lower in Asians and Blacks. Conclusions The current World Health Organisation definition of high diastolic blood pressure (,90 mmHg on two occasions) reflects values >2 standard deviations from the mean. This may be too conservative as threshold for detecting women at risk of pre-eclampsia. Further studies are required to determine the prognostic implications of gestational values ,95th centile (,130/80 mmHg) and ,5th centile (,90/50 mmHg). [source] Alfuzosin in the treatment of high leak-point pressure in children with neurogenic bladderBJU INTERNATIONAL, Issue 7 2002H. Schulte-Baukloh Objective ,To decrease the detrusor leak-point pressure (LPP) of >,40 cmH2O in children with a neurogenic bladder, using the ,1 -adrenergic blocking agent alfuzosin. Patients and methods ,Videocystometry was used to measure the detrusor LPP and several other variables before and 3 weeks after the oral administration of alfuzosin (2.5,7.5 mg/day) in 17 children (mean age 6.3 years) with an upper motor neurone lesion. Results ,The mean (sd) detrusor LPP decreased from 68 (37) to 46 (31) cmH2O (P < 0.01), reflex volume (defined as the volume at the first uninhibited bladder contraction of >,15 cmH2O) increased from 78 (69) to 112 (118) mL (+ 44%), bladder compliance increased from 9.3 (6.1) to 19.6 (14.6) mL/cmH2O (+ 111%), maximal vesical pressure decreased from 84 (40) to 70 (47) cmH2O (, 17%), and the mean number of uninhibited bladder contractions decreased from 6.3 to 3.5 (, 44%). The therapy was well tolerated; side-effects were rare and not severe. Intermittent catheterization could be avoided in six children. Conclusion ,Alfuzosin decreases the detrusor LPP in children with a neurogenic bladder caused by an upper motor neurone lesion, significantly and therapeutically, and should be considered as an alternative or addition to intermittent catheterization and anticholinergic drugs in selected patients. [source] Percutaneous transvenous mitral commissurotomy: Immediate and long-term follow-up resultsCATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 4 2002Ramesh Arora MD Abstract Percutaneous transvenous mitral commissurotomy has emerged as an effective nonsurgical technique for the treatment of patients with symptomatic mitral stenosis. This report highlights the immediate and long-term follow-up results of this procedure in an unselected cohort of patients with rheumatic mitral stenosis from a single center. It was performed in a total of 4,850 patients using double balloon in 320 (6.6%), flow-guided Inoue balloon technique in 4,374 (90.2%), and metallic valvulotome in 156 (3.2%) patients. Their age range was 6.5,72 years (mean, 27.2 ± 11.2 years) and 1,552 (32%) patients were under 20 years of age. Atrial fibrillation was present in 702 (14.5%) patients. No patient was rejected on the basis of echocardiographic score using the Wilkins criteria. Echocardiographic score of , 8 was present in 1,632 (33.6%) patients, of which 103 (2.1%) had densely calcified (Wilkins score 4+) valve. A detailed clinical and echocardiographic (two-dimensional, continuous-wave Doppler and color-flow imaging) assessment was done at every 3 months for the first year and at 6-month interval thereafter. The procedure was technically successful in 4,838 (99.8%) patients but optimal result was achieved in 4,408 (90.9%) patients with an increase in mitral valve area (MVA) from 0.7 ± 0.2 to 1.9 ± 0.3 cm2 (P < 0.001) and a reduction in mean transmitral gradient from 29.5 ± 7.0 to 5.9 ± 2.1 mm Hg (P < 0.001). The mean left atrial pressure decreased from 32.1 ± 9.8 to 13.1 ± 6.2 mm Hg (P < 0.001). Although there was no statistically significant difference in the MVA achieved between de novo and restenosed valves (1.9 ± 0.3 and 1.8 ± 0.2 cm2, respectively; P > 0.05), or between noncalcific and calcific valves (2.0 ± 0.3 and 1.8 ± 0.2 cm2, respectively; P > 0.05), on the whole MVA obtained after percutaneous transvenous mitral commissurotomy was less in restenosed and calcific valves. Ten (0.20%) patients had cardiac tamponade during the procedure. Mitral regurgitation appeared or worsened in 2,038 (42%) patients, of which 68 (1.4%) developed severe mitral regurgitation. Urgent mitral valve replacement was carried out in 52 (1.1%) of these patients. Data of 3,500 patients followed over a period of 94 ± 41 months (range, 12,166 months) revealed MVA of 1.7 ± 0.3 cm2. Elective mitral valve replacement was done in 34 (0.97%) patients. Mitral restenosis was seen in 168 (4.8%) patients, of which 133 (3.8%) were having recurrence of class III or more symptoms. Thus, percutaneous transvenous mitral commissurotomy is an effective and safe procedure with gratifying results in high percentage of patients. The benefits are sustained in a majority of these patients on long-term follow-up. It should be considered as the treatment of choice in patients with rheumatic mitral stenosis of all age groups. Cathet Cardiovasc Intervent 2002;55:450,456. © 2002 Wiley-Liss, Inc. [source] 2224: Oxygenation of the human retinaACTA OPHTHALMOLOGICA, Issue 2010E STEFANSSON Purpose Partial pressure of oxygen in the optic nerve and retina is regulated by the intraocular pressure and systemic blood pressure, the resistance in the blood vessels and oxygen consumption of the tissue. The PO2 is autoregulated and moderate changes in intraocular pressure, blood pressure or tissue oxygen consumption do not affect the retinal and optic nerve oxygen tension. Methods If the intraocular pressure is increased above 40 mmHg or the ocular perfusion pressure decreased below 50 mmHg the autoregulation is overwhelmed and the optic nerve becomes hypoxic. The levels of perfusion pressure that lead to optic nerve hypoxia in the laboratory correspond remarkably well to the levels that increase the risk of glaucomatous optic nerve atrophy in human glaucoma patients. Medical intervention can affect optic nerve PO2. Lowering the intraocular pressure tends to increase the optic nerve PO2, even though this effect may be masked by the autoregulation when the optic nerve PO2 and perfusion pressure is in the normal range. Results Carbonic anhydrase inhibitors increase retinal PO2 through a mechanism of vasodilatation and lowering of the intraocular pressure. Carbonic anhydrase inhibition reduces the removal of CO2 from the tissue and the CO2 accumulation induces vasodilatation resulting in increased blood flow and improved oxygen supply. This effect is inhibited by indomethacin but not other cyclo-oxygenase inhibitors. Conclusion Carbonic anhydrase inhibitors increase retinal blood flow and increase oxygen delivery. Glaucoma drugs and glaucoma surgery lower intraocular pressure, increase ocular perfusion pressure and blood flow. Demand of oxygen by retinal cells may be reduced through apoptosis and tissue atrophy, as well as active destruction of tissue by laser photocoagulation. [source] PERCUTANEOUS TRANSCATHETER CLOSURE OF PATENT DUCTUS ARTERIOSUS WITH AN AMPLATZER DUCT OCCLUDER USING RETROGRADE GUIDEWIRE-ESTABLISHED FEMORAL ARTERIOVENOUS LOOPCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 5-6 2008Jian-Fa Zhang SUMMARY 1The traditional antegrade wire-guided percutaneous transcatheter approach is not ideal in closing some types of patent ductus arteriosus (PDA) with abnormal morphology. The aim of the present study was to evaluate the efficacy of a retrograde wire-guided transcatheter approach for closure of some types of PDA using the Amplatzer duct occluder (ADO). 2Nineteen patients with abnormal PDA morphology, including a smaller ostium of the side of the pulmonary artery compared with the side of the descending aorta, severe calcification or tortuosity, were included in the present study. In these patients, after the antegrade approach failed to cross a wire from the pulmonary artery via the PDA to the descending aorta, a retrograde guidewire was passed through the PDA in the opposite direction, from the descending aorta to the pulmonary artery, to establish a femoral arteriovenous loop that assisted the deployment of the ADO in all 19 patients. The size of the PDA, as determined by angiography, was 3.1 ± 1.1 mm and the diameter of the ADO selected was 6.5 ± 1.5 mm. 3In 16 cases, systolic murmur disappeared after the procedure. Systolic murmur (less than Grade II) and angiographic residual shunt remained in three cases immediately after the procedure, but disappeared 1 month later. Mean pulmonary arterial pressure decreased from 33 ± 8 to 22 ± 4 mmHg in all 19 patients (P < 0.01). There were no complications during or after the procedure. 4The retrograde wire-guided technique offers an alternative approach to facilitate closure of a PDA that cannot be achieved by traditional antegrade wire-guided methods due to morphological abnormalities in the PDA. [source] Effects of mild aerobic physical exercise on membrane fluidity of erythrocytes in essential hypertensionCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 5-6 2003Kazushi Tsuda Summary 1.,The present study was undertaken to investigate the effects of aerobic physical exercise on membrane function in mild essential hypertension. 2.,Hypertensive patients were divided into an exercise group (n = 8) and a non-exercise (control) group (n = 8). Physical exercise within the intensity of the anaerobic threshold level was performed twice a week for 6 months. Membrane fluidity of erythrocytes was examined by means of electron paramagnetic resonance (EPR) and spin-labelling methods before and after the trial period in both groups. 3.,After physical exercise, blood pressure decreased significantly. 4.,Compared with the non-exercise group, in the exercise group both the order parameter (S) and the peak height ratio (ho/h -1) in the EPR spectra of erythrocytes were significantly reduced (S, 0.717 ± 0.004 vs 0.691 ± 0.008, respectively (n = 8), P < 0.05; ho/h -1, 5.38 ± 0.06 vs 4.89 ± 0.06, respectively (n = 8), P < 0.05). These findings indicated that exercise increased membrane fluidity and improved the membrane microviscosity of erythrocytes. 5.,There was no direct correlation between blood pressure reduction and the exercise-induced increase in membrane fluidity of erythrocytes. 6.,In the non-exercise (control) group, blood pressure and membrane fluidity were not changed after a 6 month follow-up period. 7., The results show that aerobic physical exercise increased erythrocyte membrane fluidity and improved the rigidity of cell membranes in hypertensive patients. The improvement of rheological properties of erythrocytes may explain, in part, the cellular mechanisms for the beneficial effects of physical exercise in hypertension. [source] Rest and exercise hemodynamics before and after valve replacement-A combined doppler/catheter studyCLINICAL CARDIOLOGY, Issue 1 2000G. Inselmann M.D. Abstract Background: Hemodynamic improvement is a common finding following valve replacement. However, despite a normally functioning prosthesis and normal left ventricular ejection fraction, some patients may show an abnormal hemodynamic response to exercise. Methods: In a combined catheter/Doppler study, rest and exercise hemodynamics were evaluated in 23 patients following aortic (n = 12) (Group 1) or mitral valve (n = 11) (Group 2) replacement and compared with preoperative findings. Patient selection was based on absence of coronary artery disease and left ventricular failure as shown by preoperative angiography. Cardiac output, pulmonary artery pressure, pulmonary capillary pressure, and pulmonary resistance were measured by right heart catheterization, whereas the gradient across the valve prosthesis was determined by Doppler echocardiography. Postoperative evaluation was done at rest and during exercise. The mean follow-up was 8.2 ± 2.2 years in Group 1 and 4.2 ± 1 years in Group 2. Results: With exercise, there was a significant rise in cardiac output in both groups. In Group 1, mean pulmonary pressure/capillary pressure decreased from 24 ± 9/18 ± 9 mmHg preoperatively to 18 ± 2/12 ± 4 mmHg postoperatively (p < 0.05), and increased to 43 ± 12/30 ± 8 mmHg with exercise (p < 0.05). The corresponding values for Group 2 were 36 ± 12/24 ± 6 mmHg preoperatively, 24 ± 7/17 ± 6 mmHg postoperatively (p < 0.05), and 51 ± 2/38 ± 4 mmHg with exercise (p < 0.05). Pulmonary vascular resistance was 109 ± 56 dyne·s·cm -5 preoperatively, 70 ± 39 dyne·s·cm -5 postoperatively (p < 0.05), and 70 ± 36 dyne·s·cm -5 with exercise in Group 1. The corresponding values for Group 2 were 241 ± 155 dyne·s·cm -5, 116 ± 39 dyne·s·cm -5 (p < 0.05), and 104 ± 47 dyne·s·cm -5. There was a significant increase in the gradients across the valve prosthesis in both groups, showing a significant correlation between the gradient at rest and exercise. No correlation was found between valve prosthesis gradient and pulmonary pressures. Conclusion: Exercise-induced pulmonary hypertension and abnormal left ventricular filling pressures seem to be a frequent finding following aortic or mitral valve replacement. Both hemodynamic abnormalities seem not to be determined by obstruction to flow across the valve prosthesis and may be concealed, showing nearly normal values at rest but a pathologic response to physical stress. [source] Global phase behavior of imidazolium ionic liquids and compressed 1,1,1,2-tetrafluoroethane (R-134a)AICHE JOURNAL, Issue 2 2009Wei Ren Abstract Novel processes involving ionic liquids with refrigerant gases have recently been developed. Here, the complete global phase behavior has been measured for the refrigerant gas, 1,1,1,2-tetrafluoroethane (R-134a) and 1- n -alkyl-3-methyl-imidazolium ionic liquids with the anions hexafluorophosphate [PF6], tetrafluoroborate [BF4] and bis(trifluoromethylsulfonyl)imide [Tf2N] from ,0°C to 105°C and to 33 MPa. All of the systems studied were Type V from the classification scheme of Scott-van Konynenburg with regions of vapor-liquid equilibrium, miscible/critical regions, vapor-liquid-liquid equilibrium, and upper and lower critical endpoints (UCEP and LCEP). The effect of the alkyl chain length has been investigated, for ethyl-([EMIm]), n -butyl-([BMIm]), and n -hexyl-([HMIm]). With increasing chain length, the temperature of the lower critical end points increases and pressure at the mixture critical points decrease. With a common cation, the temperature of the LCEP increased and the mixture critical point pressures decreased in the order of [BF4], [PF6], and [Tf2N]. © 2008 American Institute of Chemical Engineers AIChE J, 2009 [source] The electrocardiographic and hemodynamic effect of metohexital and propofol with and without esmololACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 2 2006R. Korpinen Background:, Metohexital and propofol are short-acting induction agents, which have a tendency to prolong the QTc interval of the ECG. We studied whether this increase could be prevented by combining a beta-blocking agent, esmolol, with these drugs. Simultaneously, we studied the hemodynamic effects of these combinations. Methods:, In a randomized, double-blind study, 80 ASA I,II young adults were premedicated with oxycodone and atropin and allocated to one of four groups: propofol (P), propofol + esmolol (P + E), metohexital (E) or metohexital + esmolol (M + E). The doses were 2 mg/kg propofol/metohexital and 1 mg/kg esmolol. Alfentanil 15 µg/kg was used in all groups. The hemodynamic parameters were measured non-invasively and the electrocardiographic parameters using the signal processing method. Result:, The highest QTc values, which often exceeded the normal upper limit of 440 ms, were recorded at the baseline or immediately after the administration of the induction drugs. The intervals were significantly shorter if esmolol was co-administered with either propofol or metohexital. The heart rate increased in the group M and decreased in the group P + E but remained unchanged in the groups P and M + E. Systolic and diastolic arterial pressures decreased during the study in all groups, most prominently in group P + E. Conclusions:, During the anesthesia induction, the QTc interval was significantly shorter when esmolol was co-administered with either propofol or metohexital. The hemodynamic responses were properly controlled with the combination of metohexital and esmolol as well as with propofol alone, but the combination of propofol and esmolol tended to cause hemodynamic depression. [source] Continuous Vagus Nerve Stimulation Effects on the Gut-Brain Axis in SwineNEUROMODULATION, Issue 1 2007Idoia Dķaz-Güemes DVM ABSTRACT Objectives., This study was designed to assess vagus nerve stimulation effects on the food intake pattern in swine and determine the electrical stimulus direction. Material and Methods., Fifteen Large White pigs were randomly divided into three groups, groups A,C. All animals underwent implantation of a vagus nerve stimulator at the gastro-esophogeal junction. In group A, the stimulation was switched off, whereas stimulation was switched on in groups B and C. Food intake and body weight were registered in groups A and B, but not in group C, which was used to measure direction of stimulation in the vagus and effect on heart rate and blood pressure. Variables measured in group C included the bispectral index, blood pressure, and heart rate. A Student's t -test and one-way analysis of variance were used to detect differences between groups. All animals were sacrificed to identify effects of implantation and stimulation on the vagus nerve. Results., With respect to food intake, there was no difference between groups A and B; however, body weight did register a continuous increase. During stimulation, in group C arterial pressures decreased significantly, whereas the heart rate and bispectral index increased. Conclusion., The stimulation protocol applied in this study was insufficient to cause changes in the feeding behavior of swine; however, it did increase central nervous system activity. [source] Lower oesophageal sphincter dysfunction is part of the functional abnormality in epiphrenic diverticulumBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 8 2009X. B. D'Journo Background: The pathophysiology and management of epiphrenic diverticula remain controversial. This study investigated the underlying functional abnormalities and long-term results of surgical treatment. Methods: Patients with symptoms and epiphrenic diverticula who had undergone long myotomy and Belsey Mark IV fundoplication were reviewed retrospectively. They were assessed before and after surgery by radiology, functional testing and endoscopy, and compared with a group of 40 normal volunteers. Results: The study included 23 consecutive symptomatic patients who had surgery, 20 of whom had oesophageal spastic disorders. Lower oesophageal sphincter (LOS) incoordination was considered the most constant functional abnormality (P < 0·001). After operation oesophageal diameter increased, contraction pressures decreased and peristalsis was reduced. LOS resting and gradient pressures decreased (P = 0·001). Despite unchanged acid exposure values, endoscopy revealed increased mucosal damage after operation (P = 0·003). New columnar-lined metaplasia was documented in eight patients (P = 0·013). Symptoms had decreased after a median of 61 months (P = 0·001). Conclusion: Epiphrenic diverticulum was associated with spastic dysfunction and LOS abnormalities. A long myotomy including the LOS relieved functional obstruction and symptoms, but partial fundoplication did not prevent reflux damage. Copyright © 2009 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source] |