bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of citrate on plasma aluminium concentration and aluminium excretion in the rat
Authors: Lote C. J. , Saunders H. C. , Wood J. A. , Spencer A. J. 
Published: August 2015

1. Plasma aluminium concentration and urinary aluminium excretion were monitored for 4.5 h in rats after the administration of 25 μg or 800 μg of aluminium as an intravenous bolus, either as aluminium chloride or as aluminium citrate (i.e. aluminium chloride together with sodium citrate).
2. Immediately after the bolus aluminium administration, the plasma aluminium concentration was higher in the groups given aluminium chloride than in those which received aluminium citrate, although the difference was significant (P&lt;0.05) only for the 25 μg dose. This difference between aluminium chloride and citrate indicates that the citrate form has a higher volume of distribution (i.e. is able to leave the plasma). The calculated volume of distribution for the 25 μg dose of aluminium chloride (17.5 ml) was similar to the plasma volume of the rats used (15 ml).
3. In experiments in vitro, the ultrafilterability of aqueous solutions of aluminium chloride and aluminium citrate were compared. Only 1.05 ± 0.09% of the aluminium chloride solution was ultrafilterable (aluminium concentration 28 200 ± 730 ng/ml), whereas 97.3 ± 2.4% of the aluminium citrate was ultrafilterable (aluminium concentration 42000 ± 370 ng/ml). When the filterability of aluminium in plasma was examined, the aluminium chloride ultrafilterability was identical with that in aqueous solution (1.06 ± 0.13%, aluminium concentration 19 800 ± 2956 ng/ml), but the aluminium citrate was 79.8 ± 7.1% ultrafilterable (aluminium concentration 10125 ± 591 ng/ml).
4. The differences in ultrafilterability in vitro were reflected in the urinary aluminium excretion in vivo. Even though the plasma levels of aluminium were lower in the groups that received citrate, the aluminium administered as citrate was excreted much more rapidly than the aluminium chloride. With the 25 μg dose of aluminium as chloride, 13.39 ± 0.87 μg (i.e. 53%) was excreted in 4.5 h, whereas with the citrate form 21.85 ± 3.05 μg (87%) was excreted in 4.5 h (P&lt;0.01). For the 800 μg dose of aluminium, the excretion was 160.03 ± 18.40 μg (chloride) and 451.16 ± 36.76 μg (citrate) (P&lt;0.01).
5. It is clear that renal aluminium excretion is much more efficient if aluminium citrate is administered rather than aluminium chloride. The findings raise the possibility that intravenous citrate could have therapeutic applications in patients who have accumulated aluminium.
2,3-Dinor metabolites of thromboxane A2 and prostacyclin in urine from healthy human subjects: diurnal variation and relation to 24 h excretion
Authors: Wennmalm Å. , Benthin G. , Granström E.F. , Persson L. , Winell S. 
Published: August 2015

1. Urinary levels of the 2,3-dinor metabolites of thromboxane A2 (2,3-dinor-thromboxane A2, Tx-M) and prostacyclin (2,3-dinor-6-keto-prostaglandin F1α, PGI-M) are frequently analysed as indices of platelet and endothelial activity and interaction in vivo. Despite this, little is known about the possible diurnal variations in urinary Tx-M and PGI-M in healthy human subjects, and how the urinary levels of Tx-M and PGI-M in single samples reflect their respective 24 h excretion rates. We addressed this by determining Tx-M, PGI-M and creatinine in consecutive portions of urine collected during 24 h in 15 healthy non-smoking subjects.
2. The total 24 h excretion of Tx-M and PGI-M did not differ between men (223 ± 31 and 132 ± 27 ng, respectively) and women (215 ± 44 and 127 ± 29 ng, respectively). Neither the excretion of Tx-M nor that of PGI-M displayed any significant diurnal variation.
3. The excretion of Tx-M during a 3 h period and the Tx-M/creatinine ratio in a urine sample accurately reflected the 24 h excretion of Tx-M (correlation coefficient ranges 0.74–0.94 and 0.74–0.86, respectively). The excretion of PGI-M during a 3 h period and the PGI-M/creatinine ratio in a urinary sample were accurate measures of 24 h excretion of PGI-M (correlation coefficient ranges 0.76–0.94 and 0.72–0.83, respectively). Urinary Tx-M and PGI-M expressed as simple concentrations were poor indices of their respective 24 h excretion.
4. We conclude that time-related excretions of Tx-M and PGI-M may be the best indices ex vivo of the cardiovascular formation of thromboxane A2 and prostacyclin, but that urinary creatinine-related concentrations of Tx-M and PGI-M in a urine sample are accurate measures as well.
Relative effects of fat-, carbohydrate- and protein-containing liquid diets on cardiac output in healthy adult subjects
Authors: Hawley Susan K. , Channer Kevin S. 
Published: August 2015

1. Nine healthy adult subjects consumed four types of proprietary liquid diet of similar volume and calorific value but of different nutritional composition. The effects on resting cardiac output, mean blood pressure and pulse rate were measured.
2. A significant rise in cardiac output occurred with the balanced, protein and carbohydrate diets but not with the fat diet. The greatest rise was seen with the balanced diet. Water alone had no effect on cardiac output.
3. The average time taken to reach peak cardiac output was shortest with the carbohydrate diet and longest with the fat diet.
4. The increases in cardiac output resulted from a rise in both pulse rate and stroke volume. The carbohydrate diet produced the most sustained rise in pulse rate but the least sustained elevation in stroke volume.
5. No significant changes were seen in mean blood pressure when each liquid meal was compared with water.
6. Our data show that the increase in cardiac output with liquid ingestion is related to the dietary components. These effects are additive.
Carotid arterial haemodynamics after mild degrees of lower-body negative pressure in man
Authors: Lacolley P. J. , Pannier B. M. , Slama M. A. , Cuche J. L. , Hoeks A. P. G. , Laurent S. , London G. M. , Safar M. E. 
Published: August 2015

1. Pulsatile changes in the diameter of the common carotid artery were studied transcutaneously using an echo-tracking technique in 15 normal subjects: eight subjects before and during application of graded lower-body negative pressure from −5 to −15 mmHg, and seven subjects before and during weight-bearing head-up tilt at 30 and 60 degrees.
2. In concomitant studies of changes in forearm vascular resistance, it was seen that mild lower-body negative pressure produced deactivation of cardiopulmonary receptors without changes in systemic blood pressure or heart rate.
3. After lower-body negative pressure, a significant decrease in carotid arterial diastolic diameter [from 0.662 ± 0.028 to 0.624 ± 0.033 cm (lower-body negative pressure −10 mmHg) and 0.640 ± 0.030 cm lower-body negative pressure −15 mmHg), P&lt;0.001 and &lt;0.05] was observed.
4. After head-up tilt, carotid arterial diameter was also significantly decreased at 30 and 60 degrees, whereas a significant increase in heart rate occurred only at 60 degrees and mean blood pressure did not change.
5. The study provides evidence that the geometry of the arterial wall is substantially modified by noninvasive manoeuvres such as head-up tilting and lower-body negative pressure. The latter is assumed to selectively deactivate human cardiopulmonary receptors, but the present data suggest that local changes may also influence carotid baroreceptors.
Renal divalent cation excretion in secondary hypertension
Authors: Barbagallo Mario , Resnick Lawrence M. , Sosa R. Ernest , Corbett Mary Lou , Laragh John H. 
Published: August 2015

1. To determine whether abnormal renal calcium excretion is unique to primary genetic hypertension, blood pressure and 24 h urinary excretion of calcium, magnesium, sodium and creatinine were measured in deoxycorticosterone—saline and two-kidney, one-clip Goldblatt hypertensive rats and in their respective controls on low (0.2%) and high (1.8%) dietary calcium intakes.
2. Calcium supplementation lowered blood pressure (P&lt;0.05) in deoxycorticosterone—saline rats and in control saline-loaded rats, raised blood pressure in two-kidney, one clip rats, and had no effect in sham-operated control rats.
3. On both diets, calcium excretion was higher in hypertensive than in normotensive rats. The high calcium diet increased urinary calcium excretion in all rats, but the changes in urinary calcium excretion closely paralleled the diet-induced changes in blood pressure. Thus, urinary calcium excretion in deoxycorticosterone—saline animals, in whom calcium lowered blood pressure the most, rose the least (107%). Urinary calcium excretion rose the most in two-kidney, one-clip animals (1113%), whose blood pressure also rose the most.
4. Urinary magnesium excretion was also abnormal in hypertensive rats compared with normotensive rats, falling on the high compared with the low calcium diet in normotensive rats, but not in either hypertensive strain. Furthermore, urinary magnesium excretion was closely linked to urinary calcium excretion in saline-loaded control rats (r = 0.78; P = 0.008), but was dissociated from urinary calcium excretion in deoxycorticosterone—saline rats (r = 0.02; not significant).
5. We conclude (a) that the renal handling of both calcium and magnesium is altered in secondary hypertension, and (b) that dietary calcium supplementation may have different effects on blood pressure in different forms of hypertensive disease. We hypothesize that elevated blood pressure per se may be responsible for the exaggerated calciuresis of hypertension.
Paradoxical effects of mild hypoxia and moderate altitude on human visual perception
Authors: Schlaepfer Thomas E. , Bärtsch Peter , Fisch Hans U. 
Published: August 2015

1. Prolonged (&gt; 10h) exposure to hypoxia and high altitude (&gt; 5000 m) invariably have detrimental effects on cognitive performance. Paradoxically, mild improvements in cognitive function in patients with chronic obstructive pulmonary disease after cessation of oxygen therapy have been reported.
2. We studied in each of 10 healthy subjects the effect of an acute altitude challenge [rapid helicopter transport to the Jungfraujoch (3450 m), experiment 1] and of an acute exposure to mild hypoxia (fractional inspiratory oxygen concentration 14.5%, experiment 2) on a simple test of cognitive performance (the time needed to read briefly displayed letters).
3. Under both hypoxic conditions the time needed to read briefly presented letters decreased, from 12.1 ± sd 3.8 ms to 8.3 ± 1.5 ms (P&lt;0.01) in experiment 1, and from 11.9 ± 1.9 ms to 8.1 ± 1.1 ms (P&lt;0.01) in experiment 2.
4. A rapid and mild hypoxic challenge seems to improve a simple measure of cognitive performance above normal values. The common notion that exposure to hypoxia and altitude invariably impairs cognitive performance may have to be re-evaluated.
Evidence for the indirect utilization of glucose for the synthesis of hepatic glycogen in man
Authors: King R. F. G. J. , Madan M. , Alexander D. , Boyd A. , Ibrahim K. , McMahon M. J. , Johnston D. 
Published: August 2015

1. This study was designed to test the hypothesis that three-carbon intermediates can be used in the ‘indirect’ pathway of glycogen synthesis in human liver (i.e. a route additional to the use of glucose by the ‘direct’ pathway).
2. After an overnight fast, 13 patients were given an infusion of 20% (w/v) glucose before elective abdominal operation. All received a 2.5 g bolus of 2220 kBq of selectively 3H- and 14C-labelled glucose before removal of a 1 g biopsy of liver. 3H and 14C were determined in purified glycogen as well as in glucose and lactate from samples of peripheral blood.
3. The ratio and specific activities of 3H and 14C in glycogen were found to be significantly lower than those in administered glucose. By calculation, 7–74% of glycogen repletion occurred by indirect pathways and not all of this was from the glucose supplied.
4. This study suggests that the operation of a direct pathway in man is not exclusive and that significant repletion of hepatic glycogen occurs by an indirect route.
Relationship between hepatic lipid peroxidation and fibrogenesis in carbon tetrachloride-treated rats: effect of zinc administration
Authors: Camps Jordi , Bargallo Teresa , Gimenez America , Alie Silvia , Caballeria Joan , Pares Albert , Joven Jorge , Masana Lluis , Rodes Joan 
Published: August 2015

1. Lipid peroxidation and hepatic fibrogenesis were investigated in 25 carbon tetrachloride-treated rats and in 25 control animals. Rats were further divided into two groups to receive either a standard diet or one supplemented with zinc. From each group, animals were killed at weeks 3 and 18 of the experiment for histological and biochemical assessments which included hepatic lipid peroxide and collagen concentrations and plasma zinc concentration as well as the hepatic activities of proline hydroxylase and collagenase.
2. Results indicated that oral zinc supplementation was associated with a decrease in lipid peroxidation (mean 51%; P&lt;0.05), collagen deposition (mean 32%; P&lt; 0.001) and proline hydroxylase activity (mean 30%; P&lt;0.05) at week 18, together with an increase in collagenase activity (mean 208%; P&lt;0.01) at week 3, in carbon tetrachloride-treated rats.
3. There was a significant direct correlation between lipid peroxidation and proline hydroxylase activity in carbon tetrachloride-treated rats (r = 0.52; P&lt;0.01) and also a significant inverse correlation between lipid peroxidation and plasma zinc concentration in these animals (r = −0.62; P&lt;0.001).
4. These findings are consistent with the hypothesis that hepatic lipid peroxidation plays an important role in the aetiology of hepatic fibrogenesis and that zinc mitigates the process.
Evidence against the formation of 2-amino-6-(2-formyl-5-hydroxymethyl-pyrrol-l-yl)-hexanoic acid ('pyrraline') as an early-stage product or advanced glycation end product in non-enzymic protein glycation
Authors: Smith Patricia R. , Somani Hanif H. , Thornalley Paul J. , Benn Jonathan , Sonksen Peter H. 
Published: August 2015

1. It has been suggested that 2-amino-6-(2-formyl-5-hydroxymethyl-pyrrol-l-yl)-hexanoic acid ('pyrraline') is formed as an advanced glycation end product in the Maillard reaction under physiological conditions. Antibodies were raised to caproyl-pyrraline linked to keyhole-limpet haemocyanin and were used to develop an e.l.i.s.a. and Western blotting system for the specific detection of pyrraline in samples in vivo and in vitro.
2. Human serum albumin was isolated from the serum samples of diabetic and non-diabetic subjects. Pyrraline was not detected (&lt;1.2 pmol) in any of the samples, indicating that it was not a major advanced glycation end product in vivo.
3. BSA was incubated separately with D-glucose and a model fructosamine, N-(l-deoxy-D-fructos-l-yl)-hippuryl-lysine, under physiological conditions for 30 days. Aliquots removed from the incubations at 5 day intervals contained no detectable pyrraline, indicating that pyrraline was not an early-stage product of the Maillard reaction in vitro.
4. The model fructosamine, N&gt;-(1-deoxy-D-fructos-l-yl)-hippuryl-lysine, was incubated at pH 7.4 and 37°C for 25 days during which it degraded to hippuryl-lysine and N&gt;-carboxymethyl-hippuryl-lysine. Aliquots were removed at 5 day intervals and assayed for pyrraline. None was detected (&lt;23 pmol/ml) in the course of the degradation of the fructosamine (400 nmol/ml degraded), indicating that pyrraline was not a major product of the degradation of fructosamine under physiological conditions in vitro.
5. We conclude that pyrraline is not a major intermediate or advanced glycation end product in the Maillard reaction under physiological conditions in vitro and in vivo. A previous report of immunoassay of pyrraline may have given positive results because of non-specific antibodies raised to impure hapten.
Muscle weakness in women occurs at an earlier age than in men, but strength is preserved by hormone replacement therapy
Authors: Phillips S. K. , Rook K. M. , Siddle N. C. , Bruce S. A. , Woledge R. C. 
Published: August 2015

1. The time-course of the age-related decline in specific muscle force (maximum voluntary force per cross-sectional area) in men and women was determined by measuring the maximum voluntary force and cross-sectional area of the adductor pollicis muscle in 273 subjects aged 17–90 years (176 men, 30 premenopausal women and 67 peri- or post-menopausal women who were not receiving hormone replacement therapy).
2. To determine whether the loss of specific muscle force is hormone-dependent in women, we studied a further 25 women, aged 42–72 years, who were receiving hormone replacement therapy.
3. There was no significant difference in specific force between young men and pre-menopausal women. Around the time of the menopause there was a dramatic decline in specific force in women which was prevented by the use of hormone replacement therapy. In men the weakness started later (around the age of 60 years) and the decline in specific force was more gradual, reaching the level seen in postmenopausal women after the age of 75 years.
4. The protective effect of hormone replacement therapy on muscle strength is likely to be an important contributory factor to its proven action in preventing osteoporotic fractures. The dramatic peri-menopausal decline in muscle strength is a likely explanation for the known increases in falls and Colles’ fractures around the time of the menopause.
Glycerol exchange across the human forearm assessed by a combination of tracer and arteriovenous exchange techniques
Authors: Elia M. , Khan K. , Calder G. , Kurpad A. 
Published: August 2015

1. Whole-body kinetics and regional exchange of glycerol across forearm muscle were assessed in eight lean subjects by a combination of a tracer method (infusion of [2H5]glycerol) and arteriovenous catheterization.
2. During an apparent steady state, the enrichment of glycerol in deep venous blood from the muscle bed of the forearm was about half (4.40 ± 1.72 atom per cent excess) that observed in arterialized blood (8.41 ± 4.30 atom per cent excess). Under the same conditions, the circulating concentrations of glycerol in arterialized (91 ± 24 μmol/l) and venous (87 ± 32 μmol/l) blood were similar.
3. In a further group of 37 subjects it was found that about half had a positive arteriovenous concentration difference and the other had half a negative arteriovenous concentration difference (mean −1.6 ± 11.9 μmol/l; range −25 to +22 μmol/l).
4. These results suggest: (a) that human muscle does not always release glycerol and may take it up; (b) that there is substantial isotopic exchange of glycerol across forearm muscle tissue, which is not reflected by the net exchange of glycerol; this could be due to slow equilibrium of enriched glycerol from the circulation, with unenriched free glycerol in the muscle pool, or due to the simultaneous metabolic utilization of enriched glycerol and metabolic production of unenriched glycerol; (c) that the estimation of glycerol flux rates is strongly dependent on whether the blood is arterialized or deep venous.
β
2-Adrenoceptor desensitization in cultured human airway smooth muscle
Authors: Hall Ian P. , Daykin Keri , Widdop Sophie 
Published: August 2015

1. The mechanisms underlying control of cyclic AMP responses to isoprenaline were studied in primary cultures of human airway smooth muscle cells. In these cells, isoprenaline induced concentration-related cyclic AMP formation via β2-adrenoceptor stimulation.
2. Prior incubation of cells with varying concentrations of isoprenaline (1–16 h), forskolin, prostaglandin E2 or a stable analogue of cyclic AMP all produced concentration-related desensitization of cyclic AMP responses to subsequent challenge with isoprenaline (maximum reduction with 1 μmol/l isoprenaline, 85% after 16 h). The desensitization induced over 2 h (44%) by a concentration of prostaglandin E2 which gave a similar rise in cyclic AMP levels to 1 μmol/l isoprenaline was significantly less (P &lt; 0.05) than the desensitization (62%) induced over 2 h by 1 μmol/l isoprenaline itself.
3. Isoprenaline-induced desensitization of β2-adrenoceptor-induced cyclic AMP formation was insensitive to prior exposure of cells to dexamethasone.
4. These findings suggest that isoprenaline-induced desensitization of β2-adrenoceptor-induced cyclic AMP formation in primary cultures of human airway smooth muscle cells is mediated through both a cyclic AMP-dependent and probably an additional cyclic AMP-independent pathway, and that these pathways are insensitive to inhibition by glucocorticoids.
Acute-phase protein response is impaired in severely malnourished children
Authors: Doherty J. F. , Golden M. H. N. , Raynes J. G. , Griffin G. E. , McAdam K. P. W. J. 
Published: August 2015

1. The responses of plasma levels of C-reactive protein and serum amyloid A were assessed in two groups of malnourished children.
2. Sixty-six severely malnourished children were studied at admission. Fifty of these had clinical and/or laboratory evidence of infection. C-reactive protein was not elevated in 23 (46%) and serum amyloid A was not raised in 29 (58%) of these 50 children.
3. Surviving children (n = 62) received two doses of diphtheria-pertussis-tetanus vaccine, to which the C-reactive protein and serum amyloid A responses were measured. The first was given early in recovery, the second after nutritional rehabilitation. Ten mildly malnourished children acted as controls, receiving a single dose of diphtheria-pertussis-tetanus vaccine.
4. The responses of both C-reactive protein and serum amyloid A to diphtheria-pertussis-tetanus vaccine were significantly less in early recovery than after nutritional recovery. The response of the mildly malnourished group was no different from that of the severely malnourished group in early recovery, but was less than their response on discharge.
5. The acute-phase protein response of malnourished children is impaired. This may have prognostic implications as the response plays a central role in promoting healing.