bluuebunny/crossref_metadata_2025_split huggingface dataset:
Availability of amino acids supplied intravenously in healthy man as synthetic dipeptides: Kinetic evaluation of l-alanyl-l-glutamine and glycyl-l-tyrosine
Authors: Albers S. , Wernerman J. , Stehle P. , Vinnars E. , Fürst P. 
Published: August 2015

1. For the first time utilization of intravenously administered l-alanyl-l-glutamine and glycyl-l-tyrosine was investigated by means of their kinetic behaviour after bolus injection in 10 and 11 apparently healthy male subjects (age 26.6 ± 5.7 years), respectively.
2. The injection of the synthetic dipeptides was not accompanied by any side effects or complaints.
3. The synthetic dipeptides l-alanyl-l-glutamine and glycyl-l-tyrosine were rapidly cleared from plasma. By applying a monoexponential model the elimination half-lives were found to have very similar values (3.8 ± 0.5 and 3.4 ± 0.3 min) whether alanine or glycine was occupying the N-terminal position. The estimated volume of distribution was approximately that of the extracellular space.
4. Peptide disappearance was accompanied by a prompt equimolar increase in the concentrations of the constituent amino acids alanine and glutamine as well as glycine and tyrosine.
5. The study provides firm evidence that l-alanyl-l-glutamine and glycyl-l-tyrosine are rapidly (quantitatively) hydrolysed. The results of this study may indicate a safe and efficient parenteral use of the investigated peptides as sources of free glutamine and free tyrosine.
Derivation of urinary dopamine from plasma dopa
Authors: Zimlichman Reuven , Levinson Paul D. , Kelly Gerald , Stull Robin , Keiser Harry R. , Goldstein David S. 
Published: August 2015

1. We estimated the extent to which circulating dopa (3,4-dihydroxyphenylalanine) is the source of urinary dopamine (DA; 3,4-dihydroxyphenethylamine). Tritiated dopa ([3H]dopa) was infused for 90 min into the left renal artery of seven anaesthetized foxhounds, and levels of labelled and unlabelled dopa and DA were measured in the ureteral urine and in the femoral arterial and left renal venous plasma.
2. Only a small percentage of [3H]dopa delivered to the kidneys was excreted as [3H]DA (0.59% from the left kidney, 0.68% from the right); however, the arterial concentration of endogenous dopa (1220 pg/ml) and the renal plasma flows (144 and 141 ml/min by p-aminohippurate clearances) were such that all of the urinary excretion of endogenous DA (about 1 ng/min from each kidney) could be accounted for by uptake and decarboxylation of circulating endogenous dopa.
3. Plasma dopa is the main source of urinary DA.
Increased spontaneous production of interleukin-1 together with inhibitory activity in systemic sclerosis
Authors: Westacott C. I. , Whicher J. T. , Hutton C. W. , Dieppe P. A. 
Published: August 2015

1. Increased spontaneous production of interleukin-1, measured as lymphocyte-activating factor activity, was seen in unstimulated monocytes from systemic sclerosis patients.
2. Inhibitory activity to interleukin-1 was seen in both normal and patient monocyte supernatants.
3. Inhibitory activity was significantly higher in unstimulated and stimulated monocyte supernatants from systemic sclerosis patients.
4. The net effect was an apparent decrease in lymphocyte-activating factor activity in the monocyte supernatants from systemic sclerosis patients.
5. These findings suggest a possible mechanism by which collagen deposition could be enhanced, thereby giving rise to the extensive fibrosis characteristic of systemic sclerosis.
A comparison of endogenous digoxin-like immunoreactivity and sodium transport inhibitory activity in umbilical arterial and venous serum
Authors: Morris J. F. , Poston L. , Wolfe C. D. , Hilton P. J. 
Published: August 2015

1. Endogenous digoxin-like immunoreactivity (EDLI) was measured by radioimmunoassay for digoxin in 13 paired samples of arterial and venous umbilical cord serum. EDLI was present in vein and artery, but was higher in the venous samples (P &lt; 0.025).
2. The venous cord serum inhibited the ouabain-sensitive sodium efflux rate constant of a normal mixed leucocyte population when compared with the effect of arterial cord serum (P &lt; 0.005).
3. It is suggested that the placenta may be involved in the production or metabolism of neonatal EDLI and of the inhibitor of sodium transport.
Increased urinary excretion of prostaglandin E in patients with idiopathic hypercalciuria
Authors: Henríquez-La Roche Carlos , Rodríguez-Iturbe Bernardo , Herrera José , Parra Gustavo 
Published: August 2015

1. Because urinary prostaglandin excretion could play a role in idiopathic hypercalciuria (IH), we studied the excretion of prostaglandin E (PGE), calcium and sodium at various urine flows in 21 patients (14 males) with urolithiasis and IH, seven stone formers (five males) with normal calciuria and 20 controls (11 males). Dietary composition was comparable and sodium intake was restricted to 100–120 mmol/day.
2. Analyses were performed on 30 min urine collections obtained after overnight water deprivation and during water diuresis. Male IH patients had increased levels of urinary PGE at all ranges of urine flow. PGE excretion correlated directly with urine flow in patients and controls, but the slope of this relationship in individual IH male patients was steeper than in controls (P &lt; 0.01). Calciuria correlated directly with urine output in patients with IH but not in controls. Calcium and sodium excretion were directly correlated (P &lt; 0.0001) in patients and controls. There were no significant differences between absorptive IH (seven patients) and renal IH (eight patients). There were no significant differences between stone formers with normocalciuria and control subjects.
3. The findings suggest that increased urinary PGE could play a role in the hypercalciuria syndrome, possibly by promoting natriuresis.
Renal handling of pepsinogens A and C in man
Authors: ten Kate Reinier W. , Pals Gerard , Pronk Jan C. , Bank Ruud A. , Eriksson Aldur W. , Donker Ab J. M. , Meuwissen Stephan G. M. 
Published: August 2015

1. Fractional excretions of pepsinogens A and C in the urine were investigated in 21 healthy subjects and in 38 patients with chronic renal insufficiency. In eight of the healthy subjects fractional excretions were measured again after oral administration of omeprazole for 9 days.
2. The mean fractional excretion of pepsinogen A was 27.6% (range 4.4–73.9%) in healthy subjects and remained unchanged after omeprazole administration. In patients with renal failure the mean fractional excretion of pepsinogen A was 37.9% (range 7.0–81.9%). The mean fractional excretion of pepsinogen C was 1.0% (range 0.04–6.8%) in healthy subjects and decreased after omeprazole. In patients with chronic renal diseases a sharp rise in fractional excretion of pepsinogen C was observed once glomerular filtration rate was less than 40 ml/min.
3. Fractional excretion of pepsinogen A was unexpectedly high for a negatively charged protein with a molecule mass of 40 000 daltons. This might be explained by the presence of the positively charged activation peptide. Furthermore, pepsinogen C seemed to be almost entirely reabsorbed from the glomerular filtrate and a tubular reabsorption maximum appeared to be present. Pepsinogen C may, therefore, be a new marker of tubular function. The cause of the remarkable difference in tubular handling of two quite similar low-molecular-mass proteins remains to be elucidated.
Urinary excretion of guanosine 3′:5′-cyclic monophosphate during sleep in obstructive sleep apnoea patients with and without nasal continuous positive airway pressure treatment
Authors: Krieger Jean , Schmidt Mariette , Sforza Emilia , Lehr Lydia , IMBS Jean-Louis , Coumaros Geneviève , Kurtz Daniel 
Published: August 2015

1. It has recently been shown that obstructive sleep apnoea (OSA) patients have increased urinary water and salt excretion during sleep which tends to normalize with nasal continuous positive airway pressure (CPAP) treatment.
2. To investigate the mechanisms of these changes in renal function, nocturnal urinary excretion of catecholamines and guanosine 3′:5′-cyclic monophosphate (cyclic GMP), which reflects atrial natriuretic factor (ANF) release, and next-morning plasma active renin concentrations were studied in 21 OSA patients on 2 consecutive nights, either untreated or treated with nasal CPAP.
3. In keeping with previous results, fractional urine flow and fractional Na+ and Cl− excretions were higher during untreated than during CPAP-treated nights.
4. No difference in plasma active renin concentration or in urinary excretion of noradrenaline, adrenaline, free dopamine and total dopamine could be demonstrated, but cyclic GMP excretion was significantly higher during untreated than during CPAP-treated nights.
5. The data are consistent with the hypothesis that the increased water and salt excretion in OSA patients is due to increased ANF release.
6. The proposed mechanism is an atrial distension due to increased (more negative) intrathoracic pressures during ineffective inspiratory efforts against the occluded upper airways which have been found in OSA.
Atrial natriuretic peptide levels in plasma and in cardiac tissues after chronic hypoxia in rats
Authors: Winter R. J. D. , Meleagros L. , Pervez S. , Jamal H. , Krausz T. , Polak J. M. , Bloom S. R. 
Published: August 2015

1. Atrial natriuretic peptide (ANP) levels were measured in cardiac tissues and in plasma from adult rats exposed to chronic alveolar hypoxia for periods of 2 h, 24 h and 7 days. Levels were also measured in rats that were maintained in hypoxia for 7 days and then returned to air for 24 h.
2. Plasma ANP was not altered at 2 h but was significantly increased at both 24 h and at 7 days. Plasma ANP in animals exposed to hypoxia for 7 days was normal 24 h after returning to air breathing, despite the persistence of indices of pulmonary hypertension.
3. No significant right atrial hypertrophy was observed under these conditions of chronic hypoxia. A reduction in right atrial ANP content was found at 24 h and was accompanied by a decrease in the number of electrondense granules per right atrial muscle cell. After exposure to hypoxia for 7 days, right atrial ANP and granule number was not different from control, and no alteration was found in right atrial ANP level after removal from the hypoxic environment.
4. No significant right ventricular hypertrophy was produced by exposure to hypoxia for 2 or 24 h. In the former group ventricular ANP had decreased significantly compared with control. Right ventricular hypertrophy was found in both the hypoxic groups after exposure for 7 days, when selective increases in right ventricular ANP content were found.
5. These findings are consistent with the hypothesis that ANP release occurs on exposure to chronic hypoxia and is independent of the associated cardiac hypertrophy and pulmonary vascular remodelling. The findings may have relevance to the natriuresis and reported changes in the renin-angiotensin-aldosterone axis under hypoxic conditions.
Ascorbic acid: a factor concentrated in human gastric juice
Authors: Rathbone B. J. , Johnson A. W. , Wyatt Judith I. , Kelleher J. , Heatley R. V. , Losowsky M. S. 
Published: August 2015

1. Concentrations of ascorbic acid (ascorbic and dehydro-ascorbic; A+D; measured by the 2,4-dinitrophenylhydrazine method) of nearly three times those of plasma are present in gastric juice samples from patients with normal gastric histology.
2. A significant reduction in gastric juice ascorbic acid (A+D) was observed in patients with chronic gastritis. This reduction in concentration was independent of the grade of gastritis.
3. Concentrations of ascorbic acid (A+D) in gastric biopsy specimens were consistently higher in the antrum than in the body of the stomach.
4. These data demonstrate that considerable quantities of ascorbic acid (A+D) are normally ‘secreted’ into the stomach.
5. Ascorbic acid (ascorbic only; A; measured by h.p.l.c.) was present predominantly in its biologically active form in the patients with normal gastric histology. However, in patients with gastritis, independent of grade, ascorbic acid was present predominantly in its oxidized, biologically inactive form.
A comparison of the visual analogue scale and modified Borg scale for the measurement of dyspnoea during exercise
Authors: Wilson Rachel C. , Jones P. W. 
Published: August 2015

1. The intensity of breathlessness during exercise was measured in ten normal subjects using a visual analogue scale (VAS) and a Borg scale to compare the use of the scales and their repeatability, both within the duration of a period of exercise and between tests. For each scale, subjects performed two exercise tests separated by a period of 2–6 weeks. Each exercise test consisted of two cycles of progressively increasing and decreasing workload.
2. All subjects felt confidently able to use both scales to quantify their feelings of breathlessness exclusively of other sensation. Equal preference was expressed for use of a particular scale.
3. With both scales there was a large intersubject variation in the relationship between dyspnoea score and minute ventilation (VE) (P &lt; 0.01), and in the range of the scale used.
4. There was a good correlation between the VAS and Borg scores at each level of VE (r2 = 0.71), but the VAS score was used over a wider range than the Borg score.
5. The relationship between VE and the dyspnoea score measured by the two techniques was predominantly linear. The mean r2 for VAS score/VE was 0.68 (sd 0.19) and for Borg score/VE the mean r2 was 0.75 (sd 0.13).
6. The relationships VAS score/VE and Borg score/VE were unaffected by the direction in which the workload was varied (P &gt; 0.05).
7. VE, measured at each work rate, did not differ between the two cycles (P &gt; 0.05) or between the 2 days (P &gt; 0.05).
8. With both scales, the slope of the VE-breathlessness relationship was slightly higher during the second half of the exercise compared with the first (0.05 &lt; P &gt; 0.01).
9. The scores with both scales were lower in the second test compared with the first (P &lt; 0.01): Borg 16% lower, VAS 27% lower.
10. Measurements of dyspnoea made with the Borg scale appeared to have greater stability than VAS measurements and to correlate with VE a little better.
Hypertension and renal dysfunction in primary hyperparathyroidism: effect of parathyroidectomy
Authors: Salahudeen A. K. , Thomas T. H. , Sellars L. , Tapster S. , Keavey P. , Farndon J. R. , Johnston I. D. A. , Wilkinson R. 
Published: August 2015

1. Twenty-four patients with primary hyperparathyroidism were studied before and 18 restudied 6.5 months (mean) after parathyroidectomy, to investigate the pathogenesis of the hypertension which may accompany this condition. Comparison was made with age-matched patients with essential hypertension and with normotensive control subjects.
2. There was a significant inverse relationship between mean arterial pressure and 51Cr-labelled ethylenediaminetetra-acetate (51Cr-EDTA) clearance in patients with hyperparathyroidism both before and after parathyroidectomy, but not in patients with essential hypertension.
3. Creatinine clearance appeared to overestimate glomerular filtration rate in some patients with hyperparathyroidism, falling significantly after surgery while 51Cr-EDTA clearance was unchanged. This observation may explain the failure of some previous studies to relate hypertension to impairment of renal function.
4. Plasma renin activity, plasma aldosterone and whole-body exchangeable sodium did not differ between normotensive and hypertensive patients with primary hyperparathyroidism and were unchanged after surgery.
5. Parathyroidectomy did not result in any change in blood pressure or in glomerular filtration rate measured by 51Cr-EDTA clearance.
Pharmacological modification of oxygen affinity improves deformability of deoxygenated sickle erythrocytes: a possible therapeutic approach to sickle cell disease
Authors: Keidan A. J. , Sowter M. C. , Johnson C. S. , Marwah S. S. , Stuart J. 
Published: August 2015

1. The formation of polymerized haemoglobin S in sickle cells is critically dependent on the concentration of deoxygenated haemoglobin so that compounds which increase the oxygen affinity of haemoglobin S are potential anti-sickling agents.
2. BW12C [5-(2-formyl-3-hydroxyphenoxy)pentanoic acid] and BWA589C [4-(2-formyl-3-hydroxyphenoxymethyl)benzoic acid] are aromatic benzaldehydes that cause a dose-dependent left-shift of the oxygen saturation curve of haemoglobin S by stabilization of its oxy-(R)-conformation.
3. A 5 μm pore filtration method, which is highly sensitive to polymerization of haemoglobin S, was used to demonstrate a significant improvement in the deformability of deoxygenated sickle erythrocytes at concentrations (0.75–1.5 mmol/l) of BW12C and BWA589C that are achievable in vivo. Both compounds may therefore be of value for the treatment of sickle cell disease.
4. Filtration of sickle cells through pores of 5μm diameter is a sensitive technique for evaluating the rheological effects of potential anti-sickling compounds.
Altered platelet function during mental stress and adrenaline infusion in humans: evidence for an increased aggregability in vivo as measured by filtragometry
Authors: Larsson P. T. , Hjemdahl P. , Olsson G. , Egberg N. , Hornstra G. 
Published: August 2015

1. The effects of mental stress induced by a colour word conflict test (CWT; n = 9) or 3 h infusions of placebo or adrenaline (0.4 nmol min−1 kg−1; n = 9) on platelet function in vivo were studied in 16 healthy male volunteers.
2. Platelet function was assessed by a filtragometry technique, which reflects aggregability in vivo, and by measurements of the plasma levels of β-thromboglobulin (β-TG) and platelet factor 4 (PF4).
3. Adrenaline and CWT induced marked cardiovascular responses as expected. Venous plasma adrenaline increased from 0.1–0.2 nmol/l at rest to 4.87 ± 0.42 nmol/l during adrenaline infusion and to 0.46 ± 0.10 nmol/l during CWT.
4. Filtragometry measurements were reproducible within individuals with coefficients of variation of 7.9% during placebo infusion and 5.4% for resting measurements between days.
5. Platelet aggregability, as measured by filtragometry, was similarly increased during both adrenaline infusion (P &lt; 0.05) and CWT (P &lt; 0.01).
6. The coefficients of variation for β-TG and PF4 levels were 17.3% for log β-TG and 27.9% for log PF4 between days, but could not be calculated for within-day variability. Both β-TG (P &lt; 0.05) and PF4 (P &lt; 0.01) levels decreased time-dependently during placebo infusion, indicating that long resting periods (hours) are needed to attain basal levels. Artefactual results could not be identified by evaluating βTG/PF4 ratios.
7. β-TG and PF4 levels did not decrease time-dependently during adrenaline infusion. There were no significant changes of β-TG or PF4 during CWT.
8. Our results suggest that platelet aggregability in vivo is enhanced by mental stress and high physiological levels of circulating adrenaline. The more pronounced effect of adrenaline and CWT on filtragometry readings than β-TG and PF4 levels in plasma suggests that platelet aggregability in vivo is not necessarily paralleled by increased platelet release.
Brainstem auditory evoked responses in rats with experimental chronic renal failure
Authors: Shvili Y. , Gafter U. , Zohar Y. , Talmi Y. P. , Levi J. 
Published: August 2015

1. Chronic renal failure was induced in rats by five-sixths nephrectomy. Brainstem auditory evoked response (BAER) was recorded after 3 months.
2. In the uraemic rats latency of the first wave was delayed, while the interpeak I-V latency was similar to that of the controls.
3. These results suggest a delayed neural conduction along the acoustic nerve or cochlear changes in uraemic rats.
Regulation of α- and β-myosin heavy chain messenger RNAs in the rat myocardium by amiodarone and by thyroid status
Authors: Franklyn J. A. , Green N. K. , Gammage M. D. , Ahlquist J. A. O. , Sheppard M. C. 
Published: August 2015

1. A number of the cardiovascular effects of amiodarone resemble those of hypothyroidism, prompting examination of the relationship between the actions of the drug and thyroid hormones. Amiodarone treatment of the rat was used as a model to determine the influence of the drug on thyroid hormone-regulated gene expression in the myocardium and liver; interactions between amiodarone and thyroid status were examined in hypothyroid and tri-iodothyronine (T3)-treated animals.
2. Myocardial levels of α- and β-myosin heavy chain (MHC) messenger RNAs (mRNAs) were measured by dot hybridization to specific oligonucleotide probes; myocardial actin mRNA was measured in parallel by hybridization to a complementary DNA (cDNA) probe. Hepatic levels of Spot 14 and thyroxine-binding prealbumin mRNA were similarly determined by dot hybridization to radiolabelled cDNAs.
3. Amiodarone treatment of the rat resulted in specific increases in both α- and β-MHC mRNAs in the myocardium, as well as hepatic Spot 14 mRNA, changes reversed by T3 administration.
4. Hypothyroidism resulted in a reduction in myocardial α-MHC and hepatic Spot 14 mRNAs, in contrast to amiodarone, whilst hypothyroidism and amiodarone both exerted stimulatory influences on β-MHC mRNA. Treatment of hypothyroid rats with amiodarone had no significant effect on β-MHC or Spot 14 mRNAs, but a further reduction in α-MHC mRNA, compared with the untreated hypothyroid state, was evident.
5. The demonstrated influence of amiodarone on both α- and β-MHC mRNAs and interactions between amiodarone and thyroid status in regulating MHC gene expression may be relevant to its therapeutic effect in man.
Acute effects of thiazides, with and without carbonic anhydrase inhibiting activity, on lithium and free water clearance in man
Authors: Boer W. H. , Koomans H. A. , Mees E. J. Dorhout 
Published: August 2015

1. The acute effects of chlorothiazide and bendroflumethiazide on renal Li+ clearance (CLi) were studied in Na+-restricted healthy humans during maximum water diuresis.
2. Chlorothiazide, which has marked carbonic anhydrase inhibiting activity, increased CLi by about 25%. The concomitant rise in uric acid clearance, maximum urine flow and bicarbonate excretion suggests that this drug suppressed proximal reabsorption through carbonic anhydrase inhibition, which would also explain the observed fall in glomerular filtration rate (increased glomerulotubular feedback activity).
3. Bendroflumethiazide, which lacks carbonic anhydrase inhibiting activity, did not affect CLi or any of the other above-mentioned variables.
4. It is concluded from the lack of an effect of bendroflumethiazide on CLi that Li+ is not reabsorbed in thiazide-sensitive segments of the human distal nephron. The rise in CLi after chlorothiazide is most likely due to suppressed Li+ reabsorption in the proximal tubules resulting from carbonic anhydrase inhibition.
5. The results of this study are compatible with the concept that CLi is an index of Na+ and water delivery from the proximal tubules in humans.