bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative Kinetics of Microvascular Inulin and 99mTc-Labelled Diethylenetriaminepenta-Acetic Acid Exchange
Authors: Cousins C. , Gunasekera R. D. , Mubashar M. , Mohammadtaghi S. , Strong R. , Myers M. J. , Peters A. M. 
Published: August 2015

1. After simultaneous intravenous injection as a mixture, 99mTc-labelled diethylenetriaminepentaacetic acid (99mTc-DTPA; molecular mass 492 Da) and inulin (∼6000 Da) gave arterial plasma clearance curves consisting of three exponentials, the time courses of which were not significantly different between the two solutes.
2. The ratio of 99mTc-DTPA to inuiin concentration in antecubital venous plasma (normalized to the ratio in arterial plasma at 30 s) was 0.6, significantly less than unity, within 2 min after intravenous injection, but increased to reach unity by 60 min. The minimun concentration ratio of 99mTc-DTPA to inulin in arterial plasma was 0.75 at 4 min, also rising to just above unity at 60 min.
3. The extraction fraction from plasma to interstitial space was higher for 99mTc-DTPA (∼0.5) than for inuiin (∼0.2). For both solutes, the net extraction fraction decreased with time, becoming negative at about 25 min after injection. Thereafter, the net extraction fractions remained negative, between −0.05 and −0.1, and not significantly different between the two solutes.
4. 99mTc-DTPA time—activity curves recorded over the limbs with scintillation probes were biphasic, with an initial phase corresponding closely in time with the first exponential of the arterial 99mTc-DTPA plasma clearance curve. The second phase corresponded in time to the intermediate exponential of the arterial 99mTc-DTPA plasma clearance curve.
5. The time course of net 99mTcm-DTPA extraction fraction across the forearm vascular bed was bi-exponential, with phases corresponding in time with the two phases of the limb uptake curves.
6. Deconvolution analysis of the limb time—activity curves, using the arterial time—concentration curve as the input function, gave bi-exponential 99mTc-DTPA impulse response curves in which the time courses of the exponentials corresponded with the first and intermediate exponentials of the arterial 99mTc-DTPA clearance curve.
7. The bi-exponential nature of the equilibrium of 99mTc-DTPA between vascular and interstitial compartments suggests the presence of two separate functional volumes within the interstitial space. Although 99mTc-DTPA and inuiin clearly diffuse at different rates across the endothelium, as would be expected from their disparate sizes, the similarity in the time courses of their initial exponentials and simultaneous equalization of transfer rates (i.e. when net extraction fraction was zero) is consistent with the hypothesis that inuiin moves initially into a smaller functional interstitial fluid volume than 99mTc-DTPA. The total distribution volumes, however, are not significantly different between the two solutes.
Effect of Red Wine on Endothelium-Dependent Relaxation in Rabbits
Authors: Cishek Mary Beth , Galloway Michael T. , Karim Malina , German J. Bruce , Kappagoda C. Tissa 
Published: August 2015

1. Published data on the effects of red wine, ethanol and flavonoids on endothelium-dependent relaxation are equivocal. The present study was undertaken to determine the effects of red wine, ethanol and selected flavonoids present in red wine on endothelium-dependent relaxation.
2. Aortic rings from New Zealand White rabbits were set up in organ baths (20 ml) and contracted with noradrenaline (10−6 mol/l). An attempt was made to elicit dose-dependent relaxant responses to red wine (15, 30, 40, 80 or 120 μl), ethanol (5.4, 10.8 and 16.2 μl) and the flavonoids catechin, epicatechin, quercetin and polymeric phenols (10−7 to 10−4 mol/l). In some experiments, endothelium-dependent relaxation to cumulative doses of acetylcholine (10−9 to 10−6 mol/l) was determined before and after incubating the rings for 15 min with red wine (120 μl), ethanol (16.2 μl), quercetin (10−5 mol/l), catechin (10−5 mol/l), epicatechin (10−5 mol/l) and PPs (10−5 mol/l) respectively. cGMP was also measured in some rings in the control state and after addition of 120 μl of red wine, sodium nitroprusside (10−4 mol/l) and polymeric phenols (10−5 mol/l).
3. Red wine evoked a dose-dependent relaxation in aortic rings. The highest volumes of wine (120 μl) relaxed the vessels by 71.35 ± 7.89% of the maximal contraction (8.95 ± 0.97 g). Polymeric phenols also relaxed the precontracted rings. These responses were abolished by NG-l-argine methyl ester (l-NAME) and by removal of endothelium. Addition of red wine, polymeric phenols and sodium nitroprusside increased the cGMP content of the rings. In tissues previously incubated with red wine and polymeric phenols, endothelium-dependent relaxation in response to acetylcholine was attenuated. Ethanol had no such effect.
4. Acute exposure of aortic rings to red wine and polymeric phenols evokes an endothelium-dependent relaxation which is mediated by nitric oxide. However, prior exposure to both red wine and polymeric phenols has a second effect in that it attenuates the endothelium-dependent relaxation evoked by acetylcholine. Since this effect is restored by arginine, it is likely to be due to depletion of substrate for nitric oxide synthase.
Effect of Narcotic Agents and of Bleeding on Systemic and Renal Haemodynamics in Healthy and CCl4-treated Cirrhotic Rats
Authors: Van Roey G. , Lijnen P. , Verbesselt R. , Verbruggen A. , Fevery J. 
Published: August 2015

1. The haemodynamic effects of different narcotic agents have been tested in healthy rats and in rats with cirrhosis.
2. Pentobarbital suppresses the sympathetic nervous system. Susceptibility to ketamine is unpredictable, leading to both insufficient pain relief and narcosis related mortality. The combination diazepam—fluanisone induces profound hypotension. After insertion of catheters, awake, freely moving rats are stable and not distressed. This allows repeated measurements after manipulation. Moreover, procedure-related mortality is low and rats have a better stress response.
3. In the awake animal, arterial pressure is 126 ± 10 for healthy animals, and 111 ± 16 and 102 ± 10 mmHg for cirrhotic animals without and with ascites, respectively (P = 0.018). The respective values for portal pressure are 6.9 ± 1.4, 11.6 ± 2.5 and 16.2 ± 2.9 mmHg (P = 0.0001). After a bleeding, arterial pressure is better preserved than portal pressure in the three groups (P &lt; 0.0001). Plasma volume in cirrhotic rats exceeds that of healthy rats. Plasma renin activity, aldosterone and catecholamines do not differ between the groups studied. In cirrhotic rats with and without ascites, glomerular filtration rate tends to be higher (P = 0.12), renal plasma flow is elevated (P = 0.001) and nitration fraction is lower (P = 0.002) than in healthy rats.
4. In conclusion, haemodynamic experiments in the cirrhotic rat should be performed in the awake rat. Arterial hypotension, impaired filtration fraction, enlarged plasma volume and portal hypertension are present in cirrhosis before the development of ascites. This can as well be explained by splanchnic pooling of blood, as by peripheral vasodilatation. The decrease in portal pressure with preserved arterial pressure after a bleeding protects cirrhotic rats from ongoing variceal bleeding.
Determinative Role of Peroxidized Low-Density Lipoprotein in Myocardial Thromboxane Synthesis during Pacing-Induced Ischaemia in Humans
Authors: Hsu Hsiu-Ching , Chen Ming-Fong , Lee Chii-Ming , Lee Yuan-Teh 
Published: August 2015

1. Myocardial thromboxane A2 production increases in patients with pacing-induced ischaemia and correlates with a decrease in myocardial lactate extraction. The release of myocardial thromboxane A2 before any lactate production was observed in patients with unstable angina. This study was proposed to clarify whether the early thromboxane A2 release contributed to the ongoing myocardial ischaemia and to determine which metabolites can be attributed to the thromboxane A2 release. Thirty-five patients with chest pain and positive treadmill exercise test underwent atrial pacing to the predicted maximal heart rate. The pacing was maintained at this peak rate for 10 min, then ceased. Blood samples of the ascending aorta and coronary sinus were drawn simultaneously at rest, at 2 and 10 min of peak-pacing, and 5 and 10 min after termination of the pacing; samples were used for analyses of lipid profiles, prostacyclin, thromboxane A2, lactate and lipid peroxides on plasma and low-density lipoprotein particles.
2. Twenty out of 35 patients who displayed pacing-induced ischaemia were documented by electrocardiographic evidence of ST depression &gt;2 mm developing after 2 min of peak-pacing [ischaemic group, STΔ(+)]. They had (i) negative fractional lactate extraction; (ii) pacing-induced decreases of plasma thromboxane A2 levels in the coronary sinus blood (564 ± 57 versus 479 ± 47 ng/l, P &lt; 0.05) at 2 min of peak-pacing; the data increased at 10 min of peak-pacing (564 ± 57 versus 620 ± 60 ng/l, P &lt; 0.05), then returned to baseline levels at 5 and 10 min post-pacing; (iii) significantly increased lipid peroxides on low-density lipoprotein of the coronary sinus blood at 2 and 10 min of peak-pacing (each P &lt; 0.001), as well as at 5 min post-pacing (P &lt; 0.05); (iv) significant correlation between thromboxane A2 levels and lipid peroxides on low-density lipoprotein of the coronary sinus blood samples.
3. In STΔ(+) patients, myocardial thromboxane synthesis changed before lactate production and correlated with the increase of lipid peroxides on low-density lipoprotein of the coronary venous blood. This implies that lipid peroxides on low-density lipoprotein participate in thromboxane production and play a determinative role in pacing-induced ischaemia.
Rate of Gastric Emptying is a Determinant of Postprandial Hypotension in Non-Insulin-Dependent Diabetes Mellitus
Authors: Jones K. L. , Tonkin A. , Horowitz M. , Wishart J. M. , Carney B. I. , Guha S. , Green L. 
Published: August 2015

1. Postprandial hypotension is now recognized as an important clinical problem, particularly in the elderly and in patients with autonomic dysfunction. The mechanisms responsible are poorly understood; however, impaired regulation of splanchnic blood flow and the release of gastrointestinal hormones appear to be important The effect of gastric emptying on the magnitude of the postprandial fall in blood pressure has not been evaluated.
2. The aim of this study was to determine whether there is a relationship between changes in blood pressure and the rate of gastric emptying after ingestion of 75 g of glucose in patients with noninsulin-dependent diabetes mellitus (NIDDM) and both young and older normal subjects. Sixteen patients with recently diagnosed NIDDM, median age 57 (39–79) years, 10 ‘young’ subjects with a median age of 23 (19–26) years and nine ‘older’ subjects, median age 48 (40–68) years, were measured simultaneously for gastric emptying of 75 g of glucose in 350 ml of water, blood pressure and blood glucose concentrations, commencing at approximately 10.00 hours after an overnight fast. Measurements of blood pressure were made in the sitting position immediately before glucose ingestion and at 15 min intervals up to 180 min.
3. Gastric emptying of glucose was not significantly different between the three groups [50% emptying time (T50): 95 ± 73 min in patients with NIDDM compared with 120 ± 13.2 min in the ‘young’ group and 97 ± 8.1 min in the ‘older’ group]. There was a significant fall in mean blood pressure after the glucose load in the patients with NIDDM (P &lt; 0.0001) and the ‘older’ normal subjects (P &lt; 0.05), but not the ‘young’ normal subjects. Postprandial hypotension (fall in systolic blood pressure ≥20 mmHg) was evident in seven (44%) patients with NIDDM and three (33%) ‘older’ normal subjects. The area under the change in mean blood pressure curve was related significantly to the gastric emptying T50 (r = 0.67, P &lt; 0.005) in the patients with NIDDM, but not in either control group.
4. In conclusion, in patients with recently diagnosed NIDDM the fall in blood pressure after an oral glucose load is (i) greater than in both young and older normal subjects and (ii) related to the rate of gastric emptying.
Influences on Adrenaline-Induced Thermogenesis in Obese Women and Relationship to Cardiovascular Responses
Authors: Walsh Kevin M. , Adams Calam , Sinclair Annemarie , Leen Eddie , Lean Michael E. J. 
Published: August 2015

1. In order to evaluate factors influencing thermogenesis in obesity, energy expenditure was measured before and during an adrenaline infusion (25 ng min−1 kg−1 ideal body weight for 30 min) in 22 obese females.
2. Thermogenic responses were related to body morphology, age and biochemistry. In addition, thermogenic responses were related to cardiovascular responses by simultaneously measuring blood pressure, pulse rate and cardiac output using Doppler sonography.
3. Resting energy expenditure was predicted by body weight, lean body mass and fat mass.
4. Adrenaline-induced thermogenesis was predicted by fasting insulin, low basal respiratory quotient and body fat.
5. There was a significant relationship between the cardiac output and thermogenic responses to adrenaline (r = 0.63 P &lt; 0.015) but there was no relationship to the heart rate or blood pressure responses. For every 1% increase in energy expenditure, there was a 5% increase in cardiac output.
6. In conclusion, the factors predicting resting energy expenditure and adrenaline-induced thermogenesis are different. Increased lipid oxidation and central fat distribution (with hyperinsulinaemia) are associated with a greater thermogenic response. The proportionately greater cardiac output responses may have implications for thermogenic agents designed to induce weight loss.
Lack of Effect of Vitamin E on l-Arginine-Responsive Endothelial Dysfunction in Patients with Mild Hypercholesterolaemia and Coronary Artery Disease
Authors: Chowienczyk P. J. , Kneale B. J. , Brett S. E. , Paganga G. , Jenkins B. S. , Ritter J. M. 
Published: August 2015

1. Dietary supplementation with vitamin E reduces ischaemic events in patients with established coronary artery disease and improves endothelial function in cholesterol-fed rabbits. We examined whether such dietary supplementation with vitamin E improves endothelial function in patients with mild hypercholesterolaemia and coronary artery disease.
2. Twenty patients (total cholesterol 6.8 ± 1.1 mmol/l, mean ± SD) with angiographically documented coronary artery disease were randomly allocated to receive placebo (n = 10) or vitamin E, 400 i.u. daily, (n = 10) for 8 weeks. Endothelium-dependent and independent vasodilatation within forearm vasculature was assessed by brachial artery infusion of acetylcholine (co-infused with saline vehicle and l-arginine) and nitroprusside before and after supplementation.
3. Plasma concentrations of vitamin E increased from 32.9 ± 3.8 to 69.1 ± 11.8 μmol/l (means ± SE) in the vitamin E-supplemented group (P &lt; 0.01) but did not change significantly in the placebo group. Lipid profiles remained similar before and after supplementation in both groups. Forearm blood flow responses to acetylcholine (7.5 and 15 μg/min) and nitroprusside (3 and 10 μg/min) were similar before and after supplementation in both groups. Acute intra-arterial administration of l-arginine (10 mg/min) augmented the response to acetylcholine (15 μg/min) in both groups before and after supplementation to a similar degree (mean augmentation: 60 ± 18%, P &lt; 0.01).
4. Acute administration of l-arginine reverses endothelial dysfunction in forearm vasculature of patients with mild hypercholesterolaemia and coronary artery disease but supplementation with vitamin E (400 i.u. daily) for 8 weeks does not reverse l-arginine-responsive endothelial dysfunction.
Pharmacological Characterization of Coronary Small Arteries from Pigs with Chronic Ischaemic Myocardial Remodelling
Authors: Buus Niels H. , Terp Kim , Baandrup Ulrik , Mulvany Michael J. , Nyborg Niels C. B. 
Published: August 2015

1. The effect of chronic ischaemic myocardial remodelling on small coronary artery reactivity in vitro was studied in a newly developed pig model.
2. Pigs were subjected to selective intracoronary embolizations with microspheres in the left anterior descending artery and circumflex artery causing scattered myocardial fibrosis. After an observation period of 130 days, heart dimensions and ejection fraction were determined with magnetic resonance imaging. Small arteries were isolated from the left ventricle and mounted as ring preparations in a myograph. Control arteries were taken from matched non-embolized pigs.
3. Compared with control pigs, end-systolic and -diastolic volumes increased and left ventricular mass nearly doubled in embolized pigs. This indicates substantial myocardial hypertrophy, as the fraction area of fibrosis was only 12%.
4. Coronary small arteries preconstricted with 30 mmol/l KCl showed a normal contractile response to acetylcholine and 5-hydroxytryptamine. Sensitivity of the relaxation to bradykinin was nearly 3-fold increased and also slightly enhanced to isoprenaline in arteries from embolized pigs compared with controls, whereas relaxation to 5-hydroxytryptamine in the presence of ketanserin was similar. After inhibition of nitric oxide synthase with NG-nitro-l-arginine the sensitivity to acetylcholine increased to a similar extent in arteries from embolized pigs and controls. NG-Nitro-l-arginine abolished the relaxing effects of bradykinin and of 5-hydroxytryptamine in the presence of ketanserin.
5. We conclude that both the contractile function of the smooth muscle cells and the endothelial production or action of nitric oxide is preserved or slightly enhanced in coronary small arteries from pigs with chronic myocardial remodelling.
Relationship between Serum Alkaline Phosphatase and Pyridoxal-5′-Phosphate Levels in Hypophosphatasia
Authors: Iqbal S. J. , Brain A. , Reynolds T. M. , Penny M. , Holland S. 
Published: August 2015

1. Hypophosphatasia is a disorder characterized by low serum levels of alkaline phosphatase (ALP) and a range of skeletal deformities. The levels of a number of phosphorylated metabolites, namely phosphoethanolamine and pyrophosphate, are characteristically raised. Levels of pyridoxal-5′-phosphate (PLP) have also been reported to be raised.
2. Hypophosphatasia is a rare disease and experience of measuring PLP in patients is lacking. We have had the chance to look at PLP levels in four families with hypophosphatasia, specifically to examine the quantitative relationship between ALP and PLP which has not been described before.
3. We confirmed that PLP levels are raised in hypo-phosphatasia and related to the disease severity. A significant negative linear relationship was found between the log PLP and log ALP (log PLP = 5.99−2.76 log ALP; r = − 0.85, P &lt; 0.001).
4. Measurement of PLP is simpler than some of the phosphorylated compounds, e.g. pyrophosphate. PLP may be a useful measure in patients with a suspected diagnosis of hypophosphatasia or for screening family members to detect potential heterozygotes and to monitor any response to therapy.
5. There did not appear to be any adverse clinical effects in relation to disturbed vitamin B6 metabolism in hypophosphatasia.
6. Vitamin B6 is used therapeutically in a number of conditions with monitoring of PLP levels. In these conditions PLP levels should be interpreted in conjunction with the prevailing serum ALP levels as the metabolism of these compounds is closely inter-related.
Whole Body Protein Metabolism in Human Pulmonary Tuberculosis and Undernutrition: Evidence for Anabolic Block in Tuberculosis
Authors: MacAllan Derek C. , McNurlan Margaret A. , Kurpad Anura V. , De Souza George , Shetty Prakash S. , Calder A. Graham , Griffin George E. 
Published: August 2015

1. Differing patterns of protein metabolism are seen in wasting due to undernutrition and wasting due to chronic infection.
2. We investigated whole body energy and protein metabolism in nine subjects with pulmonary tuberculosis, six undernourished subjects (body mass index &lt; 18.5 kg/m2) and seven control subjects from an Indian population. Fasting subjects were infused with l-[1-13C] leucine (2.3 μmol · h−1 · kg−1) for 8 h, 4 h fasted then 4 h fed. Leucine kinetics were derived from 13C-enrichment of leucine and α-ketoisocaproic acid in plasma and CO2 in breath.
3. Undernourished subjects, but not tuberculosis subjects, had higher rates of whole body protein turnover per unit lean body mass than controls [163.1 ± 9.4 and 148.6 ± 14.6 μmol compared with 142.8 ± 14.7 μmol leucine/h per kg, based on α-ketoisocaproic acid enrichment (P = 0.039)].
4. In response to feeding, protein oxidation increased in all groups. Tuberculosis subjects had the highest fed rates of oxidation (47.0 ± 10.5 compared with 37.1 ± 5.4 μmol · h−1 · kg−1 in controls), resulting in a less positive net protein balance in the fed phase (controls, 39.7 ± 6.2; undernourished subjects, 29.2 ± 10.6; tuberculosis subjects, 24.5 ± 93; P = 0.010). Thus fed-phase tuberculosis subjects oxidized a greater proportion of leucine flux (33.2%) than either of the other groups (controls, 24.0%; undernourished subjects, 24.0%; P = 0.017).
5. Tuberculosis did not increase fasting whole body protein turnover but impaired the anabolic response to feeding compared with control and undernourished subjects. Such ‘anabolic block’ may contribute to wasting in tuberculosis and may represent the mechanism by which some inflammatory states remain refractory to nutrition support.
Reflex Responses of Venous Capacitance Vessels in Patients with Hypertrophic Cardiomyopathy
Authors: Thomson Helen L. , Morris-Thurgood Jayne , Atherton John , McKenna William J , Frenneaux Michael P. 
Published: August 2015

1. The aim of this study was to determine if there is impaired reflex venoconstriction in patients with hypertrophic cardiomyopathy and whether this is related to a history of syncope or exercise hypotension.
2. Thirty percent of patients with hypertrophic cardiomyopathy have exercise-induced hypotension associated with a failure of arteriolar constriction. Impaired venoconstriction could exacerbate this situation.
3. We evaluated 43 patients with hypertrophic cardiomyopathy and 24 controls. Nuclear venous plethysmography was used to measure forearm venous capacitance during lower body negative pressure, splenic venous volume changes during bicycle exercise and blood pressure responses to treadmill exercise. We assessed any association between abnormal reflex venous control and a history of syncope and exercise hypotension.
4. The percentage reduction in unstressed forearm venous volume during lower body negative pressure was similar in patients and controls (8.9 ± 7.1% versus 9.7 ± 5.9%, P not significant). Patients with a history of syncope demonstrated a less marked percentage reduction in volume than those without (−2.1 ± 6.9% versus −10.6 ± 6.0%, P = 0.001). In three patients with a history of syncope there was a paradoxical increase in forearm venous volume during lower body negative pressure. During exercise there was a substantially smaller decrease in splenic venous volume in patients compared with controls (−20.1 ± 14.0% and −42.6 ± 12.6% respectively, P = 0.0001). Furthermore, there was an association between attenuated splenic venoconstriction or venodilation and exercise hypotension in patients (P = 0.005).
5. Abnormal reflex control of venous capacitance beds in patients with hypertrophic cardiomyopathy was associated with both syncope and exercise hypotension.