bluuebunny/crossref_metadata_2025 huggingface dataset:
Elevated Serum Superoxide Dismutase Levels Correlate with Disease Severity and Neutrophil Degranulation in Idiopathic Pulmonary Fibrosis
Authors: Borzì Rosa Maria , Grigolo Brunella , Meliconi R. , Fasano L. , Sturani C. , Fabbri M. , Porstmann T. , Facchini A.
Published: August 2015

1. Tissue damage in idiopathic pulmonary fibrosis is due in part to oxidant-antioxidant imbalance.

2. We evaluated the serum levels of the antioxidant enzyme Cu/Zn superoxide dismutase (EC 1.15.1.1) in 25 patients with idiopathic pulmonary fibrosis, 34 patients with sarcoidosis and 40 healthy control subjects by an enzyme immunometric assay.

3. We found that patients with idiopathic pulmonary fibrosis have higher serum Cu/Zn superoxide dismutase levels than control subjects and patients with sarcoidosis. In addition, serum Cu/Zn superoxide dismutase levels correlate with disease severity indexes in patients with idiopathic pulmonary fibrosis.

4. The increase in serum Cu/Zn superoxide dismutase level in idiopathic pulmonary fibrosis could depend on degranulation of activated neutrophils or release from damaged cells. To elucidate the contribution of neutrophil degranulation we determined the polymorphonuclear cell elastase level in the same specimens. We found a strong correlation between serum Cu/Zn superoxide dismutase and polymorphonuclear cell elastase activities, and, in patients with idiopathic pulmonary fibrosis, we observed higher levels of polymorphonuclear cell elastase than in control subjects and patients with sarcoidosis, which correlated positively with disease severity indexes.

5. Cu/Zn superoxide dismutase can catalyse the dismutation of O2 into H2Oz and generate OH · These oxygen radicals are probably the major factors responsible for tissue damage (in particular, alveolar and endothelial cells) and fibrosis in experimental lung injury.

6. Taking into account: (a) the specific enzymic activity of Cu/Zn superoxide dismutase (i.e. production of H2O2 and OH ·), (b) the possible enhancement of the effect of reduced glutathione deficiency (high H2O2) by increased Cu/Zn superoxide dismutase activity, and (c) the correlation that we found between disease severity and Cu/Zn superoxide dismutase and polyphorphonuclear cell elastase levels, we suggest that, in idiopathic pulmonary fibrosis, increased activities of Cu/Zn superoxide dismutase and polymorphonuclear cell elastase can achieve a pro-inflammatory pathogenic effect.

7. However, the results of this study of serum Cu/Zn superoxide dismutase and polymorphonuclear cell elastase concentrations in individual patients does not support a clear-cut cause-effect relationship between these enzyme levels and the clinical changes in the patients.
Vasodilatory Action of the Calcium Antagonist Amlodipine on Large and Resistance Pulmonary Arteries from Normoxic and Chronically Hypoxic Rats
Authors: Woodmansey Paul A. , Zhang Fan , Channer Kevin S. , Morice Alyn H.
Published: August 2015

1. Isolated rat aorta and pulmonary arteries were maximally precontracted with 100 mmol/l KCl, and the vasorelaxation due to the dihydropyridine calcium antagonist amlodipine was measured. The response of large pulmonary arteries (mean lumen diameter 983 μm) was directly compared with that of isolated pulmonary resistance vessels (mean lumen diameter 259 μm) from both normoxic animals and animals exposed to chronic hypoxia.

2. Amlodipine caused a significant relaxation of aorta (P <0.001). A significant relaxation of large and resistance pulmonary arteries from both normoxic and chronically hypoxic animals was also demonstrated at all doses tested (P <0.05) or less).

3. Amlodipine produced significantly more relaxation in pulmonary resistance vessels than in large pulmonary arteries from both normoxic and chronically hypoxic rats (P <0.02).

4. The action of amlodipine was slow in onset and persistent in all vessels studied. In the pulmonary vessels from normoxic animals both the rate of onset and the magnitude of effect was proportional to the drug concentration (P <0.001).

5. These results demonstrate that amlodipine is a potent inhibitor of KCl-induced contractions in rat pulmonary arteries with a preferential action in pulmonary resistance vessels.
Expression of the Three Endothelin Genes and Plasma Levels of Endothelin in Pre-Eclamptic and Normal Gestations
Authors: McMahon L. P. , Redman C. W. G. , Firth J. D.
Published: August 2015

1. Maternal vasoconstriction and fetal growth retardation are part of the syndrome of pre-eclampsia and are thought to be related to placental insufficiency. There is evidence to suggest that the powerfully vasoactive endothelin peptides might be involved in the pathogenesis.

2. The production of endothelins appears to be regulated mainly by modulation of mRNA levels, and they are thought to exert their effects locally, rather than systemically. Hence, the measurement of endothelin mRNA levels in tissues would be expected to reflect the activity of the endothelin systems.

3. RNAase protection assays, using specific antisense probes capable of distinguishing between the endothelin mRNA isoforms, have been used to examine the expression of the three endothelin genes in placental villous tissue, amniotic membrane and myometrium. Samples were taken from 15 pre-eclamptic women and from 14 women with normal gestations. Myometrium was taken at hysterectomy from five non-pregnant women as an additional control. Plasma concentrations of immunoreactive endothelin [endothelin-1, endothelin-2 and big endothelin (not distinguished)] were measured in samples taken concurrently from uterine vein and peripheral blood during surgery in ten patients.

4. The level of endothelin-1 mRNA in placental villous tissue was significantly higher in pre-eclamptic women (32 weeks gestation) than in control subjects (38 weeks gestation) (1.85 +0.26 versus 0.52 +0.09 arbitrary units, means + SEM, P <0.001) and in gravid than in non-gravid myometrium (P <0.001). Endothelin-2 was not expressed in villous tissue, but was expressed in amniotic membrane and myometrium, with relatively little difference between preeclamptic and control groups. Endothelin-3 was expressed at very low levels in all tissues examined.

5. The concentration of immunoreactive endothelin was higher in uterine than in peripheral vein blood in samples which were taken simultaneously (9.0 +1.2 versus 5.6 +0.7 pmol/l, P <0.05). Levels were not significantly different in pre-eclamptic and control groups.

6. Endothelin-1 gene expression is increased in placental villous tissue of pre-eclamptic gestations, possibly contributing to placental vasoconstriction/vascular insufficiency and hence fetal growth retardation in this disease.
Concentration-Dependent Effects of Insulin on Ca2+ Influx in Vascular Smooth Muscle Cells of Normotensive and Spontaneously Hypertensive Rats
Authors: Zhu Zhiming , Tepel Martin , Neusser Marcus , Mehring Norbert , Zidek Walter
Published: August 2015

1. The effect of insulin on cytosolic free Ca2+ concentration was measured using fura-2 in vascular smooth muscle cells of normotensive and spontaneously hypertensive rats.

2. In both strains, insulin increased cytosolic free Ca2+ concentration in a concentration range between 10−6 and 10−3 units/ml. The maximum increase in cytosolic free Ca2+ concentration was observed with 10−5 units/ml insulin (107 +25 and 82+27 nmol/l in spontaneously hypertensive rats and normotensive rats, respectively).

3. The effect of insulin was dependent on extracellular Ca2+ and was enhanced by stimulation of protein kinase C.

4. Thus insulin appears to induce a Ca2+ influx in vascular smooth muscle cells only over a certain range of concentrations. No significant difference in the response to insulin of cells from normotensive and hypertensive rats was observed.
Acetyl-CoA:lyso-Platelet-Activating Factor Acetyltransferase Activity in Neutrophils from Asthmatic Patients and Normal Subjects
Authors: Misso Neil L. A. , Gillon Robyn L. , Taylor Marcia L. , Stewart Geoffrey A. , Thompson Philip J.
Published: August 2015

1. Platelet-activating factor is a putative mediator of inflammation in asthma and the enzyme acetyl-CoA:lyso-platelet-activating factor acetyltransferase appears to be important in regulating platelet-activating factor production by leucocytes. To determine whether there are differences in acetyl-transferase activity between asthmatic patients and normal subjects, enzyme activity was assayed in neutrophil lysates from atopic asthmatic patients (n = 20), aspirin-sensitive asthmatic patients (n = 12) and healthy, non-atopic, non-asthmatic control subjects (n = 20), both basally and after stimulation with the calcium ionophore A23187.

2. For a range of acetyl-CoA concentrations, acetyl-transferase activity (nmol of [acetyl-3H]PAF min−1 mg−1 of protein) in unstimulated neutrophils from atopic asthmatic patients was significantly higher than that for normal subjects (P = 0.038) and the mean Vmax. for atopic asthmatic patients [18.4 (SD 6.9) nmol min−1 mg−1 of protein] was significantly greater than that for the control subjects [14.9 (SD 4.6) nmol min−1 mg−1 of protein P <0.05]. The mean Vmax. for aspirin-sensitive asthmatic patients [15.9 (SD 6.9) nmol min−1 mg−1 of protein] was not significantly different from that for the normal subjects.

3. The mean ratio Vmax. stimulated/ Vmax. unstimulated for acetyltransferase from atopic asthmatic patients (1.71, SD 0.45) was significantly less than that for the normal subjects (2.13, SD 0.63, P <0.05), suggesting that acetyltransferase from atopic asthmatic patients was less sensitive to stimulation with A23187 in vitro. The mean ratio Vmax. stimulated/ Vmax. unstimulated for aspirin-sensitive asthmatic patients (2.05, SD 0.71) was not significantly different from that for the normal subjects.

4. Vmax. stimulated was significantly correlated with Vmax. unstimulated in atopic asthmatic patients (P = 0.0001) and aspirin-sensitive asthmatic patients (P = 0.012), but not in normal subjects (P = 0.071).

5. These results suggest that, in atopic asthmatic patients, neutrophils may be subject to chronic priming in vivo for increased acetyltransferase activity and capacity for platelet-activating factor synthesis. In these patients the increased platelet-activating factor production may be contributing significantly to the degree of inflammation associated with their asthma.
Effect of Chronic Low-Dose Arginine Vasopressin Infusion on Body Fluid Homoeostasis during Adaptation from a High-to a Low-Sodium Diet in Normal Man
Authors: Sutters M. , Carmichael D. J. S. , Lightman S. L. , Peart W. S.
Published: August 2015

1. A diuresis occurs within the first 36 h of salt restriction. A decline in plasma arginine vasopressin concentration may contribute to both the diuresis and antinatriuresis.

2. We have studied six normal human subjects during 36 h of dietary sodium restriction. In one study subjects received an intravenous infusion of D-glucose, and in the other an infusion of arginine vasopressin (6 fmol min−1 kg−1).

3. In the D-glucose phase plasma arginine vasopressin concentration fell (1.77 +034 to 1.02 +0.13 pg/ml), urine flow increased (67.9 +113 to 89.8 + 17.1 ml/h), haemoconcentration occurred (packed cell volume 40.8 +0.3 to 42.8 +03%, protein concentration 71.6 +03 to 74.5 + 0.6 g/l), plasma sodium concentration fell (140 +0.2 to 138 +0.2 mmol/l) and plasma renin activity increased (1600+153 to 3700 + 356 pg of angiotensin I h−1 ml−1).

4. In the arginine vasopressin phase plasma arginine vasopressin concentration remained constant (13 + 0.13 to 134 +0.11 pg/ml), the diuresis was reversed (65.7 +9.9 to 52.1 +8.9 ml/h), plasma sodium concentration fell further (139.8 +0.4 to 136.1 +0.4 mmol/l), the rise in plasma renin activity was reduced (arginine vasopressin 2552 + 292; D-glucose, 3700 + 356 pg of angiotensin I h−1 ml−1) and creatinine clearance was lower in the last 12 h of salt restriction (arginine vasopressin, 96.1 +6.9; D-glucose 116.5 + 6.8 ml/min). Renal sodium excretion was unaffected by arginine vasopressin infusion.

5. We conclude that the fall in plasma arginine vasopressin concentration during dietary salt restriction, whilst not affecting renal sodium excretion, may be important in the regulation of plasma sodium concentration, plasma renin activity and glomerular filtration.
Determinants of the Renal Clearance of Exogenous Lithium in a Large Sample of a White Male Working Population
Authors: Cappuccio Francesco P. , Strazzullo Pasquale
Published: August 2015

1. The associations between the renal clearance of ingested lithium (used as a marker of renal proximal tubular sodium handling) and a number of biological variables have been investigated in an unselected sample of 592 healthy and untreated white men (aged 21–68 years) under their usual living conditions and drawn from a population at work.

2. Renal excretion of lithium was expressed both as clearance of lithium and as fractional excretion of lithium, i.e. normalized for unit of glomerular filtrate.

3. Clearance of lithium was positively associated with a number of anthropometric variables such as weight (r = 0.215; P <0.001), height (r = 0.212; P <0.001), body mass index (r = 0.122; P <0.01) and body surface area (r = 0.244; P <0.001). However, when expressed as fractional excretion of lithium many of these associations were lost or tended to be negative (weight, r = −0.107, P <0.01; body mass index, r = −0.119, P <0.01), greatly depending on the strong relationship between body size and/or mass and glomerular filtration rate. The associations between clearance of lithium and other renal variables reflected, in part, a spurious association mediated by the common relationship with glomerular filtration rate. However, when expressed as fractional excretion of lithium, only some associations were apparent (fractional excretion of sodium, r = 0.256, P <0.001; fractional excretion of uric acid, r = 0.336; P <0.001), probably indicating some plausible biological relationships. These results were confirmed by analysis of co-variance by quintiles of clearance of lithium and fractional excretion of lithium.

4. The results of the present study show that the renal excretion of ingested lithium (an approximate index of proximal tubular sodium handling in man) could be used in an epidemiological setting. However, the use of the fractional excretion of lithium rather than the clearance of lithium as such would be advisable to remove the confounding effects of age and anthropometry, at least in a white middle-aged male working population.
Tumour Necrosis Factor-α, Resting Energy Expenditure and Cachexia in Cystic Fibrosis
Authors: Elborn J. Stuart , Cordon Sally M. , Western Philip J. , MaCdonald Ian A. , Shale Dennis J.
Published: August 2015

1. We investigated the relationship between circulating tumour necrosis factor-α concentrations, resting energy expenditure, cachexia and altered intermediary metabolism in patients with cystic fibrosis and chronic pulmonary infection.

2. Twenty adult patients with cystic fibrosis and chronic bronchial sepsis covering a spectrum of severity of lung disease (forced expiratory volume in 1 s 30–100% of predicted) were compared with 10 age matched, healthy, non-cystic fibrosis subjects.

3. Circulating tumour necrosis factor-α, C-reactive protein and neutrophil elastase-α1-antiproteinase complex concentrations were determined simultaneously with glycerol, non-esterified fatty acids, catecholamines, anthropometric indices and resting energy expenditure (ventilated hood method).

4. Weight, body mass index and arm muscle mass were reduced in patients with cystic fibrosis compared with healthy control subjects (P <0.01), whereas mean resting energy expenditure was increased [121 versus 101% predicted, mean difference 19.2% (95% confidence interval 11.0-27.4%), P <0.001]. Circulating concentrations of glycerol (P <0.01), non-esterified fatty acids (P <0.01), adrenaline (P <0.05), tumour necrosis factor-α, C-reactive protein and neutrophil elastase-α1-antiproteinase complex (P <0.01) were increased in patients compared with control subjects [tumour necrosis factor-α 96.9 versus 24.7 pg/ml, mean difference 72.2 pg/ml [95% confidence interval 27.7-116.7 pg/ml), P <0.001]. Resting energy expenditure was significantly related to tumour necrosis factor-α levels and forced expiratory volume in 1 s.

5. In patients with cystic fibrosis and chronic pulmonary sepsis changes in resting energy expenditure, body composition and intermediary metabolism are consistent with the systemic effects of the host inflammatory response, which may be responsible for cachexia in adult patients. In particular these changes are consistent with the action of tumour necrosis factor-α, which was detected in the circulation during a period of apparent clinical stability.
Rat Renal, Aortic and Pulmonary Endothelin-1 Receptors: Effects of Changes in Sodium and Water Intake
Authors: Michel Harald , Bäcker Angela , Meyer-Lehnert Harald , Migas Iris , Kramer Herbert J.
Published: August 2015

1. In the present study we investigated, first, the effects of high Na+ intake and, second, the effects of water deprivation on plasma endothelin-1 concentration and urinary endothelin-1 excretion and on endothelin receptors in membranes of renal glomeruli and papillae and of aortic smooth muscle and lung tissue from 32 female Sprague-Dawley rats.

2. After 5 weeks of high Na+ intake (n = 8) urinary Na+ excretion was 10.5 + 1.3 compared with 1.6 + 0.2 mmol/24h in controls. Body weight, plasma osmolality, plasma endothelin-1 concentration (23 + 6 versus 28 + 3 fmol/ml) and urinary endothelin-1 excretion (6.1 + 13 versus 4.7 + 0.3 pmol/24 h) remained unchanged.

3. The characteristics of endothelin-1 receptors in glomeruli, papillae, aortic smooth muscle and lung tissue from salt-loaded rats were not different from those of controls.

4. After 48 h water deprivation (n = 8) body weight had decreased, whereas packed cell volume and plasma and urine osmolalities had increased compared with controls (n = 8) (P <0.05). Plasma endothelin-1 concentration (40 + 6 versus 21 + 2 fmol/ml) was higher (P <0.01) and urinary endothelin-1 excretion (1.0 + 0.2 versus 2.8 + 03 pmol/24 h) was lower than in controls (P <0.01).

5. Water deprivation was accompanied by increases in endothelin-1 binding sites in glomeruli (Bmax. 4.8 + 0.4 versus 3.6 + 0.2 pmol/mg of protein; P <0.05) with unchanged receptor affinity (Kd 56 + 9 versus 57 + 8 pmol/l), in papillae (Bmax. 8.0 + 0.7 versus 6.2 + 0.5 pmol/mg of protein; P <0.05) with unchanged Kd (78 + 6 versus 63 + 4 pmol/l) and in aortic smooth muscle cells (Bmax. 3.5 + 0.2 versus 2.8 + 0.2 pmol/mg of protein; P <0.05) in which Kd rose to 307 + 27 versus 180 + 22 pmol/l (P <0.05). Endothelin-1 receptors in lung tissue were unaltered (Bmax. 10.0 + 03 versus 103 + 0.8 pmol/mg of protein; Kd 152 + 12 versus 137 + 14 pmol/l).

6. Our results suggest that the peripheral endothelin-1 system may play a role in the adaptation to changes in body water content rather than in Na+ balance.
A Comparison of the Renal and Neuroendocrine Effects of Two 5-Hydroxytryptamine Renal Prodrugs in Normal Man
Authors: Li Kam Wa T. C. , Freestone S. , Samson R. R. , Johnson N. R. , Lee M. R.
Published: August 2015

1. The effects of 1 h intravenous infusions of equimolar amounts (45 nmol min−1 kg−1) of two putative 5-hydroxytryptamine renal prodrugs, 5-hydroxy-L-tryptophan and γ-L-glutamyl-5-hydroxy-L-tryptophan, were investigated in a randomized, placebo-controlled, cross-over study in nine healthy male subjects.

2. Cumulative urinary 5-hydroxytryptamine excretion over the 3 h observation period rose by about 370-fold after 5-hydroxy-L-tryptophan and 390-fold after γ-L-glutamyl-5-hydroxy-L-tryptophan when compared with placebo infusion. Urinary 5-hydroxy-L-tryptophan excretion was three times higher after administration of γ-L-glutamyl-5-hydroxy-L-tryptophan than after 5-hydroxy-L-tryptophan infusion. Urinary 5-hydroxyindole-3-acetic acid excretion after 5-hydroxy-L-tryptophan infusion was significantly greater than that after γ-L-glutamyl-5-hydroxy-L-tryptophan administration. Urinary dopamine excretion was not affected by either compound when compared with placebo.

3. 5-Hydroxy-L-tryptophan significantly reduced urine flow rate and urinary sodium excretion. γ-L-Glutamyl-5-hydroxy-L-tryptophan was antinatriuretic but did not affect urine output. These changes occurred without significant alterations in effective renal plasma flow and glomerular filtration rate.

4. Both 5-hydroxy-L-tryptophan and γ-L-glutamyl-5-hydroxy-L-tryptophan significantly increased plasma aldosterone concentration without a concomitant rise in plasma renin activity. The increase after γ-L-glutamyl-5-hydroxy-L-tryptophan was smaller and delayed. 5-Hydroxy-L-tryptophan, but not γ-glutamyl-5-hydroxy-L-tryptophan, increased serum growth hormone concentration.

5. There was a significant increase in diastolic blood pressure after 5-hydroxy-L-tryptophan administration, but not after γ-L-glutamyl-5-hydroxy-L-rryptophan.

6. These results show that both prodrugs generate 5-hydroxytryptamine. The antinatriuresis after both compounds is presumably mediated by intrarenally generated 5-hydroxytryptamine and this appears to be predominantly a tubular effect. The urinary metabolite data and greater extrarenal effects produced by 5-hydroxy-L-tryptophan indicate that the glutamyl derivative is relatively more selective for the kidney than 5-hydroxy-L-tryptophan.
Sulphide Impairment of Substrate Oxidation in Rat Colonocytes: A Biochemical Basis for Ulcerative Colitis?
Authors: Roediger W. E. W. , Duncan A. , Kapaniris O. , Millard S.
Published: August 2015

1. Isolated colonic epithelial cells of the rat were incubated for 40 min with [6-14C]glucose and n-[1-14C]batyrate in the presence of 0.1-2.0 mmol/l NaHS, a concentration range found in the human colon. Metabolic products, 14CO2, acetoacetate, β-hydroxybutyrate and lactate, were measured and injury to cells was judged by diminished production of metabolites.

2. Oxidation of n-butyrate to CO2 and acetoacetate was reduced at 0.1 and 0.5 mmol/l NaHS, whereas glucose oxidation remained unimpaired. At 1.0-2.0 mmol/l NaHS, n-butyrate and glucose oxidation were dose-dependently reduced at the same rate.

3. To bypass short-chain acyl-CoA dehydrogenase activity necessary for butyrate oxidation, ketogenesis from crotonate was measured in the presence of 1.0 mmol/l NaHS. Suppression by sulphide of ketogenesis from crotonate (−10.5 + 6.1%) compared with control conditions was not significant, whereas suppression of ketogenesis from n-butyrate (−36.00 + 5.14%) was signficant (P = <0.01). Inhibition of FAD-linked oxidation was more affected by NaHS than was NAD-linked oxidation.

4. L-Methionine (5.0 mmol/l) significantly redressed the impaired β-oxidation induced by NaHS. Methionine equally improved CO2 and ketone body production, suggesting a global reversal of the action of sulphide.

5. Sulphide-induced oxidative changes closely mirror the impairment of β-oxidation observed in colonocytes of patients with ulcerative colitis. A hypothesis for the disease process of ulcerative colitis is that sulphides may form persulphides with butyryl-CoA, which would inhibit cellular short-chain acyl-CoA dehydrogenase and β-oxidation to induce an energy-deficiency state in colonocytes and mucosal inflammation.
Indomethacin Stimulates Basal Glucose Production in Humans without Changes in Concentrations of Glucoregulatory Hormones
Authors: Corssmit E. P. M. , Romijn J. A. , Endert E. , Sauerwein H. P.
Published: August 2015

1. To investigate whether indomethacin affects basal glucose production, we measured hepatic glucose production in six healthy postabsorptive subjects on two occasions: once after administration of indomethacin (150 mg orally) and once after administration of placebo.

2. Glucose production was measured by primed, continuous infusion of [3-3H]-glucose.

3. Indomethacin administration resulted in an increase in glucose production from 10.9 (SEM 0.3) μmol min−1 kg−1 to a maximum of 16.5 (SEM 1.6) μmol min−1 kg−1 (P <0.05) within ∼1 h, whereas in the control experiment glucose production declined gradually (P <0.01) (P <0.05 indomethacin versus control). There were no differences in plasma concentrations of insulin, C-peptide and counter-regulatory hormones between the two experiments.

4. Since indomethacin administration resulted in an increase in glucose production in the absence of any changes in concentrations of glucoregulatory hormones, we conclude that indomethacin stimulates hepatic glucose production through other mechanisms.
Forearm Substrate Utilization during Exercise after a Meal Containing Both Fat and Carbohydrate
Authors: Griffiths A. John , Humphreys Sandy M. , Clark Mo L. , Frayn Keith N.
Published: August 2015

1. Whilst the provision of exogenous carbohydrate has been shown to be beneficial to endurance exercise performance, little attention has been paid to the possibility of dietary manipulation of the availability of fat.

2. Ten normal subjects were studied on two occasions: after an overnight fast (postabsorptive state) and after a meal containing 80g of fat and 80g of carbohydrate (fed state). Forearm substrate exchange was studied during 60 min of isometric forearm exercise (5s contraction, 5s relaxation).

3. In the fed state concentrations of plasma triacylglycerol (1510 ± 150 versus 850 ± 80 μmol/l, P < 0.01), blood ketone bodies (151 ± 21 versus 80 ± 10 μmol/l, P < 0.01) and plasma insulin (17 ± 3 versus 7 ± 1 m-units/l, P < 0.01) were elevated compared with the postabsorptive state; plasma glucose and non-esterified fatty acid concentrations were not significantly different.

4. Forearm blood flow and O2 consumption each increased about 6-fold during exercise, with no differences between the two nutritional states. The potential contribution of individual substrates to forearm O2 consumption (a calculation which is independent of blood flow) was assessed: for triacylglycerol it was significantly greater in the fed state (P < 0.01). The sum of the potential contributions of triacylglycerol, non-esterified fatty acids, glucose and ketone bodies to forearm O2 consumption was significantly greater, both before and during exercise, in the fed than in the postabsorptive state (P < 0.05), implying the sparing of endogenous (forearm) fuels.

5. These studies highlight the potential for manipulation of substrate supply during exercise by feeding meals containing both carbohydrate and fat.
Nitrogen Homoeostasis in Man: Diurnal Changes in Nitrogen Excretion, Leucine Oxidation and Whole Body Leucine Kinetics during a Reduction from a High to a Moderate Protein Intake
Authors: Quevedo Marcelo R. , Price Gill M. , Halliday David , Pacy Paul J. , Millward D. Joe
Published: August 2015

1. The adaptation of the diurnal cycle of nitrogen (N) homoeostasis during a change in protein intake was investigated with diurnal measurements of N and leucine balance and turnover during a reduction from a high to a moderate protein intake in normal adults.

2. In experiment 1, during a 9 day period after a reduction from 1.82 to 0.77 g of protein day−1 kg−1, N excretion fell slowly at a similar rate in fed and fasted states so that the lowered intake was unable to replete any of the postabsorptive losses for 3 days. There was a marked negative N balance, which persisted throughout the study, although with a significant reduction in N losses in both fed and fasted states on day 4, balances during days 4–9 (−32.8 ± 28.3 mg of N day−1 kg−1) were less negative than during days 1–3 (−79.1 ± 60.4 mg of N day−1 kg−1).

3. In experiment 2, during a 14 day period after a reduction from 1.89 to 0.77 g of protein day−1kg−1, [1-13C]leucine oxidation and turnover were measured by primed intravenous infusion, during fasting and feeding in subjects before and on days 3, 7 and 14 after the dietary change. Leucine oxidation fell by 32% (P < 0.05) on day 3 in the fed state and by 12% (P < 0.05) during fasting, falling further in each case by day 7 with improved balance. N losses predicted from the leucine oxidation fell with the same time course as the measured N excretion in experiment 1, but the predicted losses were lower, so that the overall negative leucine balance on day 3 (−22 ± 17 mg of N day−1 kg−1) became positive by day 7 (+ 15 ± 21 mg of N day−1 kg−1).

4. Rates of protein synthesis and degradation calculated from leucine kinetics indicated that feeding the high protein diet resulted in a 60% inhibition of degradation and a 15% (P < 0.05) stimulation of synthesis. With the moderate protein diet the improving fasting balance between days 3 and 7 was the result of a non-significant fall in degradation. Feeding the moderate protein diet abolished the stimulation of synthesis and significantly lowered the inhibition of degradation (31 ± 9%). The improving fed balance between days 3 and 7 was the result of changes in the rates of synthesis and degradation which were below the detection limits of the methods. The daily sum of fasted and fed rates of synthesis (4.33 g day−1 kg−1) did not change with the lowered intake, whereas the rate of degradation increased significantly from 3.61 to 4.26 g day−1 kg−1).

5. Thus, in response to a lower protein intake, adaptation of amino acid oxidation and N excretion occurs, with a similar pattern of gradual reductions in fed and fasted periods during the first week. Thus protein requirements are influenced by the habitual protein intake, which influences the nutritional demand for protein for repletion of fasting losses, the efficiency of such repletion and the consequent dietary need.
Gender Differences in Urinary Kallikrein Excretion in Man: Variation Throughout the Menstrual Cycle
Authors: Albano J. D. M. , Campbell S. K. , Farrer A. , Millar J. G. B.
Published: August 2015

1. Urinary kallikrein excretion was measured in healthy male subjects and in healthy pre- and post-menopausal females.

2. Urinary kallikrein excretion was shown to be constant throughout a 24 h period. Individual male subjects showed little fluctuation in urinary kallikrein excretion; within-subject variance accounted for 1.65% of the total.

3. Female subjects with ovulatory menstrual periods excreted significantly more kallikrein than post-menopausal females and males.

4. Pre-menopausal females showed a much greater within-subject variation in urinary kallikrein excretion and this could be related to the stage of the menstrual cycle, with significantly greater urinary kallikrein excretion in the luteal phase than in the follicular phase.

5. Plasma renin activity and plasma aldosterone concentration also showed a menstrual variation, with concentrations in the luteal phase being significantly higher than those in the follicular phase.

6. The rise in urinary kallikrein excretion in the luteal phase could be abolished by oral administration of the aldosterone antagonist spironolactone.

7. Urinary kallikrein excretion in post-menopausal females was similar to the range found in males, and showed no cyclic changes over a 4 week period.

8. Gender and menstrual status should be taken into account in studies of the physiological role of tissue kallikreins.
Lipoprotein Profiles in a Family with Two Mutants of Apolipoprotein E: Possible Association with Hypertriglyceridaemia but Not with Dysbetalipoproteinaemia
Authors: Zhao Shui-Ping , Van den Maagdenberg Arn M. J. M. , Vroom Ton F. F. P. , Hooft Ferdinand M. Van't , Leuven Jan A. Gevers , Havekes Louis M. , Frants Rune R. , Van Der Laarse Arnoud , Smelt Augustinus H. M.
Published: August 2015

1. The plasma lipoprotein profiles of eight members of a Dutch pedigree spanning three generations where two rare apolipoprotein E mutants, APOE*3(Cys-112→Arg; Arg-251→Gly) and APOE*2(Val-236 →Glu), segregate were analysed to determine whether the APOE mutants were associated with dyslipidaemia.

2. The proband, a 51-year-old Caucasian male, was a carrier of APOE*3(Cys-112→Arg; Arg-251→Gly) and his spouse was a carrier of APOE*2(Val-236→Glu). Four other family members were carriers of one or both of the mutant APOE genes.

3. The plasma cholesterol and triacylglycerol concentrations were markedly elevated in the proband and were classified as type IV hyperlipoproteinaemia. The plasma triacylglycerol concentration was moderately increased in a sister, who was a carrier of APOE*3(Cys-112→Arg; Arg-251→Gly), and in the son, who was a compound heterozygote for both mutant APOE alleles. Normal plasma lipid levels were observed in all other family members. In the plasma samples of the proband and his family members β-very-low-density lipoprotein was not detectable and the molar ratio of very-low-density lipoprotein-cholesterol to very-low-density lipoprotein-triacylglycerol was less than 0.9. The concentration of intermediate-density lipoprotein was within normal limits.

4. None of the family members carrying APOE*3-(Cys-112→Arg; Arg-251→Gly) and/or APOE*2(Val-236→Glu) exhibited lipoprotein abnormalities characteristic of familial dysbetalipoproteinaemia, although three family members carrying APOE*3-(Cys-112→Arg; Arg-251→Gly) showed hypertriglyceridaemia.
β-Adrenoceptor Subtypes Mediating the Metabolic Effects of BRL 35135 in Man
Authors: Wheeldon N. M. , McDevitt D. G. , McFarlane L. C. , Lipworth B. J.
Published: August 2015

1. The aim of the present study was to evaluate the metabolic responses produced in man by the β-adrenoceptor agonist BRL 35135, and to determine which of these responses are β3-, rather than β1- or β2-, mediated.

2. Eight normal male subjects received single oral doses of BRL 35135 (8 mg) or the selective β2-adrenoceptor agonist salbutamol (8 mg) after pretreatment with placebo, bisoprolol (5 mg) as a selective β1-antagonist or nadolol (20 mg) to block β1-and β2-, but not β3-adrenoceptors.

3. BRL 35135 and salbutamol produced a significant fall in serum potassium concentration compared with placebo, in keeping with β2-adrenoceptor stimulation. Both drugs also produced a significant increase in serum glucose, insulin and lactate concentrations, which mirrored the hypokalaemic response, being unaffected by selective β1-blockade (bisoprolol), but completely blocked by nadolol. BRL 35135 (but not salbutamol) also produced a significant rise in serum free fatty acid and glycerol concentrations, which appeared to be β2-mediated.

4. A significant increase in basal metabolic rate occurred with both BRL 35135 and salbutamol. In the case of salbutamol, this effect appeared to be mediated solely by β2-adrenoceptors, whereas BRL 35135 produced a thermogenic response which could only be partially accounted for by a combination of β1- and β2-adrenoceptor stimulation.

5. These results infer the possibility of thermogenic β3-adrenoceptors in man, although these do not appear to be involved in the control of carbohydrate or fat metabolism.
Tumour and Host Tissue Responses to Branched-Chain Amino Acid Supplementation of Patients with Cancer
Authors: McNurlan M. A. , Heys S. D. , Park K. G. M. , Broom J. , Brown D. S. , Eremin O. , Garlick P. J.
Published: August 2015

1 Rates of protein synthesis have been measured from the incorporation of 57 mg of l-[1-13C]leucine/kg for 90 min into muscle tissue and colorectal tumours removed at surgery from cancer patients.

2. For the 20 h preceding surgery and during the measurement of protein synthesis, the patients received intravenous saline, conventional intravenous nutrition (0.2 g of N and 103 non-protein kJ/kg body weight) or intravenous nutrition enriched with the branched-chain amino acids leucine, isoleucine and valine (0.2 g of N with 30% from branched-chain amino acids and 103 non-protein kJ/kg body weight).

3. Conventional intravenous nutrition resulted in a significant stimulation of the rate of protein synthesis in both muscle tissue (2.64 ± 0.75%/day versus 1.78 ± 0.51%/day in saline control, means ± SD) and tumour tissue (43.9 ± 10.3%/day versus 22.6 ± 5.6%/day in saline control).

4. Pre-operative nutrition enriched with branched-chain amino acids was less effective than conventional intravenous nutrition in stimulating protein synthesis in both muscle and tumour. The rates of protein synthesis were 2.12 ± 0.41%/day in muscle and 33.7 ± 5.3%/day in the tumours.

5. The expression of proliferating cell nuclear antigen in sections of the tumours showed changes with intravenous feeding of the two different amino acid mixtures that were similar to the changes in protein synthesis, and these two variables were significantly correlated. This is evidence that feeding with conventional mixtures and mixtures enriched with branched-chain amino acids stimulates tumour growth.

6. In this study the mixture enriched with branched-chain amino acids provided no clear advantage for cancer patients, since a smaller response to branched-chain amino acids was observed in both tumours and host muscle tissue.
Studies in Surgical Trauma: Oxidative Stress in Ischaemia-Reperfusion of Rat Liver
Authors: Liu P. T. , Symons A. M. , Howarth J. A. , Boulter P. S. , Parke D. V.
Published: August 2015

1. Hypovolaemic shock associated with surgical trauma has been studied in a rat liver ischaemia-reperfusion model by determination of oxidative stress, lipid peroxidation and tissue infiltration of polymorphonuclear leucocytes.

2. Liver ischaemia alone resulted in slight liver oedema and polymorphonuclear leucocyte infiltration, a slight increase in thiobarbituric acid-reacting substances (an index of lipid peroxidation) and decreases in liver reduced glutathione and total radical-trapping antioxidant parameter, indices of oxidative stress. Ischaemia plus 30 min of reperfusion further increased liver oedema, polymorphonuclear leucocyte infiltration and thiobarbituric-acid reacting substances, and further decreased liver reduced glutathione and total radical-trapping antioxidant parameter.

3. After 60 and 90 min of reperfusion, oedema (40% increase), polymorphonuclear leucocyte infiltration (40-fold increase) and thiobarbituric-acid reacting substances (20-fold increase) were maximal, and liver reduced glutathione (75–95% decrease) and total radical-trapping antioxidant parameter (85–90% decrease) were at a minimum.

4. All parameters were exacerbated by 24 h starvation. Liver reduced glutathione closely paralleled total radical-trapping antioxidant parameter, and ischaemia alone depleted both by 30% in fed rats and 50% in fasted rats.

5. Oxidative stress and lipid peroxidation were associated more with the period of reperfusion and polymorphonuclear leucocyte infiltration. Polymorphonuclear leucocyte infiltration into lung also occurred after 90 min of liver reperfusion.

6. Possible mechanisms of hepatic ischaemia-reperfusion-induced oxidative stress are discussed.
Sympathetic Restraint of Baroreflex Control of Heart Period in Normotensive and Hypertensive Subjects
Authors: Lucini Daniela , Pagani Massimo , Mela Giuseppe Sandro , Malliani Alberto
Published: August 2015

1. We assessed the effects of changing levels of sympathetic drive on the gain of baroreflex control of the sino-atrial node, in normotensive and hypertensive subjects.

2. Autoregressive spectral and cross-spectral analysis of R—R interval and systolic arterial pressure (non-invasive Finapres method) variabilities providing an estimate of baroreflex gain through the frequency domain index α were performed on data from 63 normotensive and 78 mild hypertensive subjects. Subjects were studied at rest and during active orthostatism, which induces sympathetic predominance. Seven control subjects and 14 hypertensive subjects were also studied after chronic atenolol treatment, to attenuate β-adrenoceptor-mediated responses.

3. In both normotensive and hypertensive subjects, the index α was reduced by active standing and increased by chronic β-adrenoceptor blockade. Furthermore, at rest, the index at was correlated with R—R variance and appeared significantly reduced with age. The age-related negative correlation of the index α was no longer evident during the standing-induced increase in sympathetic drive, in both normotensive and hypertensive subjects.

4. The index α, a non-invasive frequency domain estimate of the overall gain of baroreflex control of the sino-atrial node, which appears to be reduced in essential hypertension, is negatively modulated by physiological increases in sympathetic drive, and augmented by pharmacological blockade of β-adrenoceptors.

5. In essential hypertension the enhanced sympathetic drive present already at rest, and the simultaneous reduction of the gain of baroreflex mechanisms, are the expression of a complex alteration in neural cardiovascular control.
Short-Term Variation in the Elastic Properties of a Muscular Artery in Humans
Authors: Hofstra L , Willigers J. M. , Huvers F. C. , Schaper N. C. , Kester A. D. M. , Kitslaar P. J. E. H. M. , Hoeks A. P. G.
Published: August 2015

1. Information on the interaction between mechanical strain and the elastic properties of large arteries could give insight to the origin of haemodynamic vascular injury, possibly resulting in formation of atherosclerotic plaques. Intra-individual variation in the elastic properties of muscular arteries measured using non-invasive techniques has been observed. This variation could be due to changes in blood pressure, since the elastic properties of muscular arteries are strongly non-linear.

2. The objective of the present study was to evaluate variability in the elastic properties of a muscular artery over a time period of up to 1 h. Furthermore, the relation between changes in elastic properties and alterations in blood pressure was studied. With a non-invasive high-resolution ultrasound technique, the diameter and distension of the femoral artery were assessed by repeated measurements in 10 healthy subjects (mean age 27 ± 2.9 years) under resting conditions over 40–60 min. Intra-arterial blood pressure of the contralateral common femoral artery and heart rate were recorded simultaneously. From the distension and pulse pressure, the distension/pressure ratio was calculated, a measure of the compliance. For each parameter the variation coefficient was computed.

3. In all subjects a considerable variation was found in distension (mean variation coefficient 14.8%) but not in pulse pressure (mean variation coefficient 3.7%). The expected positive correlation between pulse pressure and distension was absent in eight subjects. As a consequence, large intra-individual variation was found in the distension/pressure ratio (mean variation coefficient 15.3%). When plotted as function of time, gradual fluctuations in the distension/pressure ratio were observed.

4. In the majority of the subjects no correlation between diastolic pressure and diameter was observed. Therefore the non-linear relation between diastolic diameter and distension cannot explain the observed variation in the distension/pressure ratio. A possible explanation might be a modification of the elastic properties of this large muscular artery by vasoactive substances and the central nervous system.

5. Under resting conditions, the elastic properties of the femoral artery in humans show large intra-individual variation with time. This variation cannot be explained by alterations in diastolic diameter, suggesting that active vessel wall behaviour is responsible for the variability. Due to the variability of the distension/pressure ratio in this large artery, a single measurement cannot give a proper characterization of the elastic properties.
Time Course of Systemic and Renal Plasma Prostanoid Concentrations and Renal Function in Ovine Hyperdynamic Sepsis
Authors: Weber Andreas , Schwieger Ian M. , Poinsot Olivier , Morel Denis R.
Published: August 2015

1. We continuously recorded systemic and renal haemodynamic changes, and arterial, renal venous and urinary concentrations of thromboxane B2, 6-keto-prostaglandin F1α and prostaglandin E2, and determined their relationship to renal function in an ovine model of progressive hyperdynamic sepsis.

2. Nine chronically instrumented unanaesthetized sheep were given a continuous intravenous infusion of Escherichia coli endotoxin (20 ng min−1 kg−1) for 3 days.

3. Within the first 12 h of infusion, endotoxin induced a major hypotensive septic syndrome, including a persistent 30% reduction in mean arterial pressure, a 50% decrease in systemic vascular resistance and a 50% increase in mean pulmonary artery pressure, associated with severe lactacidaemia.

4. Renal blood flow decreased by 40%, and creatinine clearance, urine flow, and fractional sodium excretion decreased by more than 75%, of baseline values. After 12 h of endotoxin infusion, cardiac output increased two-fold and renal blood flow recovered to baseline values, whereas creatinine clearance remained depressed. Four sheep died between 13 and 22 h of endotoxaemia; these animals (allocated to group 1) presented a significantly and persistently more reduced renal blood flow (−23%) and creatinine clearance (−77%) after 4 h than the remaining five sheep (allocated to group 2), which survived more than 36 h (−16% and −21%, respectively), whereas systemic and pulmonary haemodynamic and gas exchange data remained similar in both groups.

5. The more pronounced decreases in renal blood flow, creatinine clearance and urine flow in group 1 were associated with higher plasma renin activity and plasma 6-keto-prostaglandin F1α concentrations and a lower fractional urinary excretion of 6-keto-prostaglandin F1α than in group 2, whereas plasma thromboxane B2 concentrations were similarly increased in both groups. Plasma prostaglandin E2 concentrations and urinary excretion were not notably affected by endotoxin infusion in either group.

6. Our results are not in favour of a significant renal production of any of these three prostanoids during endotoxaemia. In both groups, values of creatinine clearance were linearly correlated with simultaneous mean arterial pressure values after starting endotoxin infusion (group 1: creatinine clearance = 1.99 × mean arterial pressure −105, r = 0.95; group 2: creatinine clearance = 2.06 × mean arterial pressure −104, r = 0.80).

7. These findings indicate that during continuous endotoxin administration in sheep (1) the renal haemodynamic and functional responses are biphasic, (2) severe impairment of renal function is associated with elevated plasma renin activity and 6-keto-prostaglandin F1α plasma concentrations and with early fatality, and (3) renal filtration capacity directly depends on renal perfusion pressure, suggesting a loss of renal filtration autoregulation during endotoxaemia.