bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pulmonary Vascular Reactivity and Ischaemia-Reperfusion Injury in the Rat
Authors: Messent M. , Griffiths M. J. D. , Evans T. W. 
Published: August 2015

1. The endothelium has been shown to modulate the pulmonary vascular response to hypoxia in the rat. Acute lung injury is associated with loss of hypoxic pulmonary vasoconstriction and increased pulmonary vascular permeability. Similar loss of the vascular response to hypoxia is seen after ischaemia-reperfusion injury of the myocardium.
2. The effects of reperfusion injury on pulmonary endothelial integrity, as shown by the albumin escape index and hypoxic pulmonary vasoconstriction, were investigated in isolated, blood-perfused rat lungs.
3. Ischaemia for 0.5 h, which itself caused no increase in the albumin escape index, was followed by reperfusion for 0.25 h, 0.5 h and 1 h. Controls were subjected to 2 h of perfusion only (n = 5 in all groups). The pulmonary pressor response to hypoxia (fractional inspired oxygen concentration, 3%) was measured before and after ischaemia-reperfusion, and the dilator response to acetylcholine was measured after ischaemia-reperfusion in all cases.
4. Ischaemia-reperfusion significantly increased the albumin escape index after 0.5 h (mean ± SEM, 1.40 ± 0.27) and 1 h (2.0 ± 0.30) compared with controls (0.54 ± 0.30, P &lt;0.05 in both cases). The pulmonary pressor response to hypoxia was augmented significantly after reperfusion when compared with baseline hypoxic pulmonary vasoconstriction (change from baseline: 13.2 ± 4.63 and 22.2 ± 7.1% after 0.5 and 1.0 h of reperfusion, respectively, P &lt;0.05). Vasorelaxation of sustained hypoxic vasoconstriction using acetylcholine was similar in both control lungs and those subjected to ischaemia-reperfusion.
5. These results suggest that the pressor response to hypoxia is augmented after damage to the pulmonary vascular endothelium induced by ischaemia-reperfusion. Although this may be due to diminished release of endothelium-derived relaxing factors, the normal vasodilator response to acetylcholine suggests the phenomenon is not due to a reduction in the release of endothelium-derived relaxing factor/nitric oxide.
Human Pyruvate Dehydrogenase Complex as An Autoantigen in Primary Biliary Cirrhosis
Authors: Palmer Jeremy M. , Bassendine Margaret F. , James Oliver F. W. , Yeaman Stephen J. 
Published: August 2015

1. The sera of more than 90% of patients with primary biliary cirrhosis contain antimitochondrial antibodies which react with the E2 component of the pyruvate dehydrogenase complex, identified as the major autoantigen in primary biliary cirrhosis. All previous studies in this area have utilized protein derived from animal tissue or have used recombinant human pyruvate dehydrogenase complex E2 expressed in Escherichia coli.
2. We report the preparation and characterization of native pyruvate dehydrogenase complex and pyruvate dehydrogenase complex E2 from human heart tissue and its application in studies of immune reactivity with the sera of patients with primary biliary cirrhosis.
3. The immune reactivity of sera from patients with primary biliary cirrhosis versus the bovine and human E2/X components of pyruvate dehydrogenase complex was indistinguishable in both immunoblotting and the more sensitive e.l.i.s.a.
4. These findings suggest that the reactivity of sera from patients with primary biliary cirrhosis against the major autoantigen of the disease is a property of that antigen, independent of its human or bovine origin. Furthermore, this justifies the use of bovine pyruvate dehydrogenase complex in past and future work on primary biliary cirrhosis antibody reactivity.
Relationship between Insulin Release, Antinatriuresis and Hypokalaemia after Glucose Ingestion in Normal and Hypertensive Man
Authors: Natali Andrea , Galvan Alfredo Quiñones , Santoro Donatella , Pecori Neda , Taddei Stefano , Salvetti Antonio , Ferrannini Eleuterio 
Published: August 2015

1. Insulin simultaneously causes hypokalaemia and antinatriuresis, and it has been suggested that the two effects are tightly coupled. Whether these actions are preserved in patients with essential hypertension is not known.
2. Eight hypertensive patients and eight normotensive control subjects were studied before and after the ingestion of 75 g of glucose. Despite similar glycaemic profiles, the patients showed a hyperinsulinaemic response incremental area 49 ±8 versus 27 ± 6 nmoll−1 3h, P &lt;0.04) but a blunted hypokalemic response (−7±1 versus −16±1%, P &lt;0.001). Both absolute and fractional urinary excretion of sodium and potassium were significantly decreased during glucose-induced hyperinsulinaemia in hypertensive patients as well as in normotensive subjects (P &lt;0.05 for all changes).
3. To test whether hypokalaemia is required for insulin-induced antinatriuresis, each hypertensive patient received another oral glucose load during which enough potassium chloride was given to clamp the plasma potassium concentration at baseline. Under these conditions, significant insulin-induced antinatriuresis still occurred. In addition, whereas the glycaemic profile was superimposable, the response of the plasma insulin concentration was significantly greater with than without maintenance of the plasma potassium concentration (total area 79 ± 14 versus 63 ± 8 nmoll−1 3h, P &lt;0.04).
4. We conclude that (a) insulin causes antinatriuresis, antikaliuresis and hypokalaemia under physiological conditions; (b) in hyperinsulinaemic (insulin-resistant) patients with essential hypertension, the anti-natriuretic action of insulin is quantitatively preserved; and (c) clamping plasma potassium levels prevents insulin-induced antikaliuresis but not anti-natriuresis, and potentiates the insulin secretory response to glucose.
Effect of Inhalation of 30% Nitrous Oxide on Spectral Components of Heart Rate Variability in Conscious man
Authors: Galletly D. C. , Tobin P. D. , Robinson B.J. , Corfiatis T. 
Published: August 2015

1. Periodicities in cardiac interbeat interval may be resolved into discrete frequency components by applying Fourier analysis to heart rate time series. Low-frequency components (&lt;0.15 Hz) are believed to be under parasympathetic and sympathetic control, whereas a higher frequency component in phase with respiration is believed to be entirely parasympathetic. The ratio of the power in the low-/high-frequency spectrum gives an estimate of sympathetic/para-sympathetic balance.
2. This study examined, using heart rate variability spectral analysis, the cardiac autonomic effects of breathing 30% N2O in normal subjects. While supine, the inhalation of N2O caused a significant fall in high-frequency power and a rise in the low-/high-frequency spectrum. During air breathing, tilting caused a significant rise in the mean blood pressure, heart rate, low-frequency power and low-/high-frequency spectrum. During N2O breathing, tilting caused a rise in the heart rate and the mean blood pressure, but no significant alteration in the power of individual spectral components. During tilting, the heart rate, the low-frequency and low-/high-frequency spectrum were less when breathing N2O than when breathing air.
3. These observations are consistent with the effect of N2O being an enhanced sympathetic balance of sinoatrial control, with the primary effect being through reduced parasympathetic tone. Enhanced sympathetic dominance of heart rate variability was seen on standing while subjects breathed air, but this effect was blunted with N2O.
Effects of Decreased Glutamine Supply on Gut and Liver Metabolism in vivo in Rats
Authors: Heeneman Sylvia , Deutz Nicolaas E. P. 
Published: August 2015

1. It has recently been suggested that glutamine may be a conditionally essential nutrient rather than a non-essential amino acid. Therefore, administration of methionine sulphoximine was used to create a model of decreased arterial glutamine concentrations for 4 days. Glutamine consumption in portal-drained viscera and liver was measured after an overnight fast by determining fluxes and intracellular concentrations in normal rats, methionine sulphoximine-treated rats and pair-fed controls. Moreover, fluxes and intracellular concentrations of several other amino acids and ammonia and production of urea by the liver were determined concomitantly.
2. Methionine sulphoximine treatment for 4 days resulted in a 50% decrease in arterial glutamine concentration. Although the glutamine consumption and the intracellular glutamine concentration of the intestine were reduced by 50% at day 4, no changes in intestinal amino acid and ammonia metabolism were observed.
3. In the liver, glutamine consumption was reduced and ammonia uptake was increased, but urea synthesis was not changed. The decreased intracellular glutamine, glutamate, aspartate and ammonia concentrations coincided with a substantial reduction in liver branched-chain amino acid production.
4. These results suggest that reduced intestinal glutamine uptake does not induce marked changes in intestinal amino acid metabolism. The decreased liver branched-chain amino acid production suggests a reduction in the net liver protein degradation rate during methionine sulphoximine treatment.
Muscle Blood Flow during Intermittent Exercise: Comparison of the Microdialysis Ethanol Technique and 133Xe Clearance
Authors: Hickner R. C. , Bone D. , Ungerstedt U. , Jorfeldt L. , Henriksson J. 
Published: August 2015

1. Local skeletal muscle blood flow was monitored using the microdialysis ethanol technique and 133Xe clearance during intermittent isometric contractions (5 s on/10 s off) of the thigh at 0–60% of the maximal voluntary isometric contraction force.
2. A linear increase in blood flow over a 25-fold range was detected using both l33Xe clearance and the microdialysis ethanol technique.
3. The median correlation coefficient between percentage maximal voluntary isometric contraction force and the ethanol outflow/inflow ratio, a marker of blood flow, was r = −0.98 (−0.94 to −0.99) (median and range, n = 6). The corresponding correlation coefficient for 133Xe clearance was r = 0.97 (0.92–0.98), the correlation coefficient between the ethanol outflow/inflow ratio and 133Xe clearance being r = −0.92 (−0.89 to −0.94).
4. Dialysate glucose concentration, although affected by blood flow, was not always significantly correlated with blood flow changes (r = 0.70; 0.51-0.95).
5. It may be concluded that the ethanol technique provides a valid measure of changes in local skeletal muscle blood flow. The data furthermore show that a linear increase in thigh skeletal muscle blood flow exists during the studied protocol of intermittent isometric contractions.
Effects of Nitric Oxide Donors in Vitro on the Arachidonic Acid-Induced Platelet Release Reaction and Platelet Cyclic GMP Concentration in Pre-Eclampsia
Authors: Hardy E. , Rubin P. C. , Horn E. H. 
Published: August 2015

1. Platelet activation in vivo occurs in healthy pregnancy and is more pronounced in pre-eclampsia.
2. This study has investigated: (i) the inhibitory potency of the nitric oxide donors 3-morpholinosydnonimine and sodium nitroprusside, on the platelet release reaction in vitro in non-pregnant, healthy pregnant and pre-eclamptic women; (ii) the concentration of cyclic GMP during incubation of washed platelets with sodium nitroprusside in a separate group of non-pregnant, healthy pregnant and pre-eclamptic women.
3. The half-maximal inhibitory concentration of sodium nitroprusside, in the presence of a phosphodiesterase inhibitor, for inhibition of the platelet release reaction was lower in the pre-eclamptic subjects than in the non-pregnant subjects (P &lt; 0.05).
4. Several of the pre-eclamptic women were studied again postnatally. The half-maximal inhibitory concentrations of sodium nitroprusside and 3-morpholinosydnonimine were higher in the postnatal than in the antenatal sample (P &lt; 0.02).
5. Peak platelet cyclic GMP responses to sodium nitroprusside were significantly higher in the pre-eclamptic women than in the healthy pregnant and non-pregnant women.
6. These results suggest that platelets are more sensitive to the inhibitory effects of nitric oxide donors in pre-eclampsia.
Increased Systolic Blood Pressure in Adult Rats Induced by Fetal Exposure to Maternal Low Protein Diets
Authors: Langley Simon C. , Jackson Alan A. 
Published: August 2015

1. Possible associations between maternal nutrition in pregnancy and non-communicable diseases of adulthood were assessed using a rat model. Rats were habituated to diets containing a range of protein levels (18, 12, 9 and 6% by weight), over a 14 day period, before mating. The low protein diets were maintained throughout pregnancy. Lactating mothers and their offspring were transferred to a standard chow diet (20% protein).
2. Pregnant rats demonstrated a graded response to the diets, with those fed 9 and 6% protein tending to consume less energy and gain less weight than 18% protein fed controls. Litter size and newborn death rates were not significantly altered by the low protein diets.
3. Offspring of 12 and 9% protein fed dams were grossly normal, gaining weight at a similar rate to those born to 18% protein fed control rats. Offspring of the 6% protein fed dams were smaller than pups from all other groups, over a 21 week period.
4. At 9 weeks of age, systolic blood pressure was determined in the offspring. All offspring from the three low protein groups were found to have significantly elevated blood pressure (15–22 mmHg) relative to the control group. An inverse relationship between maternal protein intake and the systolic blood pressure of the offspring was observed. Blood pressure remained elevated in the offspring of the 9 and 6% protein fed dams until 21 weeks of age. The observed hypertension was associated with increased pulmonary angiotensin-converting enzyme activity in the low protein groups.
5. The data are consistent with the hypothesis that poor maternal nutrition in pregnancy may irreversibly impair aspects of physiological and biochemical function in the fetus. This has potential adverse consequences for the later health of the offspring.
Evaluation of Multi-Frequency Bio-Impedance Analysis for the Assessment of Extracellular and Total Body Water in Surgical Patients
Authors: Hannan W. J. , Cowen S. J. , Fearon K. C. H. , Plester C. E. , Falconer J. S. , Richardson R. A. 
Published: August 2015

1. Multi-frequency bio-impedance analysis has been used to estimate extracellular and total body water in a heterogeneous group of 43 surgical patients (23 males, 20 females).
2. Radioisotope-dilution methods were used for the measurement of extracellular and total body water.
3. Resistance and reactance were measured between wrist and ankle at frequencies from 5 kHz to 1 MHz.
4. Extracellular and total body water were estimated by multiple stepwise regression using the radioisotope values as the dependent variables. The parameters included in the regression were: resistance and reactance at each frequency, body habitus parameters, plasma albumin and plasma sodium.
5. The standard errors of the estimates between the measured and esitmated values were 1.73 litres (coefficient of variation 9.6%) and 2.17 litres (coefficient of variation 6.0%) for extracellular and total body water, respectively.
6. These errors represent a useful improvement relative to those obtained from anthropometric estimates. However, the improvements relative to the use of a single frequency (50 kHz) are not clinically significant.
Amino Acid Profile and Aromatic Amino Acid Concentration in Total Parenteral Nutrition: Effect on Growth, Protein Metabolism and Aromatic Amino Acid Metabolism in the Neonatal Piglet
Authors: Wykes Linda J. , House James D. , Ball Ronald O. , Pencharz Paul B. 
Published: August 2015

1. The protein and amino acid utilization of two commercially available amino acid solutions, one egg-patterned (Vamin), the other human-milk-patterned (Vaminolact), were studied in piglets receiving total parenteral nutrition. It was hypothesized that Vaminolact was deficient in total aromatic amino acids, so a third group received a human-milk-patterned amino acid solution with added phenylalanine.
2. The piglets were on total parenteral nutrition for 8 days from day 2 or 3 of life. They all received a total energy intake of 1040 kJ day−1 kg−1 with macro-nutrient intakes of 14.6g of amino acid, 27.4 g of glucose and 9.4 g of fat day−1 kg−1.
3. Nitrogen balances were performed on days 3-8 of total parenteral nutrition. On day 8 a primed constant infusion of (1-14C]-phenylalanine was given to measure phenylalanine flux and fractional conversion to tyrosine. Transamination catabolites of phenylalanine and tyrosine were measured in urine on day 7.
4. The piglets receiving Vaminolact gained significantly less weight (0.86 kg compared with 1.18 kg for Vamin and 1.20 kg for phenylalanine-supplemented Vaminolact; P &lt; 0.02) and nitrogen (1435 mg day−1 kg−1 compared with 1601 mg and 1836 mg day−1 kg−1 for the other groups; P &lt; 0.0001).
5. The piglets receiving Vamin had high plasma phenylalanine levels (2234 μmol/l compared with 156 μmol/l for Vaminolact and 399 μmol for phenylalanine-supplemented Vaminolact; P &lt; 0.0001). Those receiving Vamin also had an elevated excretion of phenylalanine transamination metabolites and low plasma lysine levels. Phenylalanine flux was highest in the Vamin group, intermediate in the phenylalanine-supplemented Vaminolact group and lowest in the Vaminolact group.
6. We conclude that Vaminolact is limiting in aromatic amino acids and that the addition of phenylalanine to the level in Vamin significantly improves growth and nitrogen retention; however, increasing the phenylalanine content of total parenteral nutrition is not the most metabolically suitable way to provide aromatic amino acids in neonatal total parenteral nutrition.
Studies with Radiolabelled Serum Amyloid P Component Provide Evidence for Turnover and Regression of Amyloid Deposits In Vivo
Authors: Hawkins Philip N. 
Published: August 2015

1. Quantitative scintigraphic and turnover studies, utilizing the specific binding affinity of serum amyloid P component for amyloid fibrils, have been developed as a tool for evaluating amyloid deposits in vivo.
2. Serial studies in over 300 patients have shown characteristic, diagnostic tissue distributions of amyloid in different types of amyloidosis. There is generally a poor correlation between quantity of amyloid and associated organ dysfunction.
3. Contrary to previous expectations, regression of amyloid has been demonstrated systematically for the first time: AA, AL and variant transthyretin-associated amyloid deposits often regress rapidly, and sometimes completely, if the supply of fibril protein precursors is substantially reduced.
Physiology and Pathophysiology of Heart Rate and Blood Pressure Variability in Humans: Is Power Spectral Analysis Largely An Index of Baroreflex Gain?
Authors: Sleight Peter , La Rovere Maria Teresa , Mortara Andrea , Pinna Gianni , Maestri Roberto , Leuzzi Stefano , Bianchini Beatrice , Tavazzi Luigi , Bernardi Luciano 
Published: August 2015

1. It is often assumed that the power in the low-(around 0.10 Hz) and high-frequency (around 0.25 Hz) bands obtained by power spectral analysis of cardiovascular variables reflects vagal and sympathetic tone respectively. An alternative model attributes the low-frequency band to a resonance in the control system that is produced by the inefficiently slow time constant of the reflex response to beat-to-beat changes in blood pressure effected by the sympathetic (with or without the parasympathetic) arm(s) of the baroreflex (De Boer model).
2. We have applied the De Boer model of circulatory variability to patients with varying baroreflex sensitivity and one normal subject, and have shown that the main differences in spectral power (for both low and high frequency) between and within subjects are caused by changes in the arterial baroreflex gain, particularly for vagal control of heart rate (R—R interval) and left ventricular stroke output. We have computed the power spectrum at rest and during neck suction (to stimulate carotid baroreceptors). We stimulated the baroreceptors at two frequencies (0.1 and 0.2 Hz), which were both distinct from the controlled respiration rate (0.25 Hz), in both normal subjects and heart failure patients with either sensitive or poor baroreflex control.
3. The data broadly confirm the De Boer model. The low-frequency (0.1 Hz) peak in either R—R or blood pressure variability) was spontaneously generated only if the baroreflex control of the autonomic outflow was relatively intact. With a large stimulus to the carotid baroreceptor it was possible to influence the low-frequency R—R but not low-frequency blood pressure variability. This implies that it is too simplistic to use power spectral analysis as a simple measure of autonomic balance
its underlying modulation is more complex than generally believed.
4. It may be that power spectral analysis is more a sensitive indicator of baroreflex control, particularly of vagal control, than direct evidence of autonomic balance. of course, there is often a correlation between the gain of the reflex and the autonomic balance of vagus and sympathetic. These considerations may help our understanding of some conditions, such as exercise or heart failure, when the power spectral analysis method fails to identify increased sympathetic discharge; this failure may partly be explained by the decrease in baroreflex sensitivity which occurs in these two conditions.
Brain Natriuretic Peptide: Effect on Left Ventricular Filling Patterns in Healthy Subjects
Authors: Clarkson Peter B. M. , Wheeldon Nigel M. , MacLeod Catherine , Coutie Wendy , MacDonald Thomas M. 
Published: August 2015

1. Elevated plasma concentrations of brain natriuretic peptide are found in conditions associated with impaired left ventricular diastolic function. The purpose of this study was to determine whether this peptide actually plays a physiological role in improving myocardial performance in diastole.
2. Nine normal subjects received infusions of brain natriuretic peptide or placebo in a randomized, double-blind, crossover study. Brain natriuretic peptide infusion produced a significant reduction in isovolumic relaxation time (means and 95% confidence interval for difference−10.8 ms, −14.5 to −7.0 ms) (P &lt; 0.01) and significantly increased both the peak E/A velocity (0.54, 0.14–0.94) (P &lt; 0.05) and the E/A time velocity integral (1.09, 0.20–1.98) (P &lt; 0.05).
3. These responses were evident at concentrations of brain natriuretic peptide that produced no associated effects on blood pressure, heart rate or stroke distance.
4. Brain natriuretic peptide infusion in normal subjects significantly reduces isovolumic relaxation time and improves transmitral Doppler flow profiles, suggesting that this peptide may be important in the control of left ventricular diastolic relaxation in man.