bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of acid-base disturbances on renal handling of magnesium in the dog
Authors: Wong Norman L. M. , Quamme Gary A. , Dirks John H. 
Published: August 2015

1. Clearance and micropuncture studies were performed in four groups of acutely thyropara-thyroidectomized animals to study the effects of alkalosis and acidosis on the renal handling of magnesium.
2. Our results indicate that chronic metabolic acidosis reduces, whereas acute metabolic alkalosis enhances, magnesium reabsorption.
3. The site within the nephron where absorption of magnesium increases or decreases during acid-base disturbances was beyond the late proximal tubule.
4. Tubular fluid bicarbonate was also measured in these experiments, and the results indicated that magnesium reabsorption in the distal tubule correlated to bicarbonate delivery. However, whether this was a direct or an indirect effect of bicarbonate on magnesium transport could not be delineated.
Blood flow in skeletal muscle of tetraplegic man during postural changes
Authors: Andersen Erling Bo , Boesen Finn , Henriksen Ole , Sonne Michael 
Published: August 2015

1. Relative changes in blood flow and vascular resistance in arm and leg muscle during head-up tilt at 45° were studied in eight patients with complete cervical spinal cord transection and in 13 healthy volunteers.
2. Muscle blood flow was measured by the local 133Xe washout method.
3. In forearm muscle kept at heart level blood flow remained constant in the tetraplegic patients during head-up tilt, in contrast to that seen in the normal subjects, where blood flow decreased by 30%. In the dependent leg muscle, head-up tilt caused a decrease in blood flow of 46% and 40% in the patients and normals, respectively. Abolition of the local veno-arteriolar axon reflex, by inducing local counter-pressure to prevent venous distension in the dependent leg muscle, reduced the decrease in blood flow to 24% and 23%, respectively. Thus, the vascular response to head-up tilt differed significantly in forearm muscle between the two groups, whereas no difference was seen in the leg muscle.
4. The absence of the vasoconstrictor response in forearm muscle indicates that postural sympathetic reflexes to this region depend on sympathetic reflexes integrated in centres located rostrally to the spinal cord. The results further suggest that local veno-arteriolar axon reflexes as well as spinal reflexes contribute to the observed vasoconstriction in the leg muscle.
Urogastrone–epidermal growth factor concentrations in prostatic fluid of normal individuals and patients with benign prostatic hypertrophy
Authors: Gregory H. , Willshire I. R. , Kavanagh J. P. , Blacklock N. J. , Chowdury S. , Richards R. C. 
Published: August 2015

1. High concentrations (272 ± 33 ng/ml) of urogastrone-epidermal growth factor were measured in prostatic fluid from normal males by a specific radioimmunoassay.
2. Significantly lower concentrations (155 ± 24 ng/ml) were observed in the prostatic fluid of patients with benign prostatic hypertrophy than in the age-matched normal controls (2P &lt; 0.01).
3. The growth factor content of seminal fluid was accounted for by the contribution of prostatic fluid.
4. Immunochemical studies failed to show evidence of synthesis within the gland nor could high affinity receptors for the protein be demonstrated in membrane preparations of the gland.
Release of adenosine and its metabolites from activated human leucocytes
Authors: Mann Jonathan S. , Renwick Andrew G. , Holgate Stephen T. 
Published: August 2015

1. Human leucocytes whose adenine nucleotide pool was prelabelled with [3H]adenine were investigated for their capacity to release adenosine and its metabolites and histamine when activated with the calcium ionophore A23187, antiimmunoglobulin E and the chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (f-MLP).
2. Sixty-nine per cent of the 3H-label assimilated by the cells was incorporated into their adenine nucleotide pool in the ratio adenosine 5′-phosphate (AMP):adenosine 5′-pyrophosphate (ADP):adenosine 5′-triphosphate (ATP), 3:1:1. Spontaneous release of label from leucocytes plateaued at 5 min at 22.1 ± 4.2% of the total radiolabel incorporated and mainly consisted of hypoxanthine, inosine and adenosine.
3. Activation of cells with the calcium ionophore A23187 (1.0 μmol/l) caused a net increase in [3H]purine release above baseline of 27.9 ± 4.6% accompanied by a net basophil histamine release of 46.6 ± 9.4%. A23187 (1.0–3.0 μmol/l) caused a parallel concentration-dependent release of labelled purines and histamine. Purified mononuclear cells and granulocytes exhibited a similar ionophore-dependent capacity to release [3H]purines.
4. The distribution of label did not significantly differ between supernatants of activated and non-activated cells. Preincubation of cells with dipyridamole (10μmol/l) and erythro-9-(2-hydroxy-3)-nonyladenine (EHNA) (10μmol/l) to inhibit uptake and catabolism of adenosine respectively, produced an increase in adenosine at the expense of hypoxanthine recovered from the supernatant of both ionophore-stimulated and resting cells.
5. Activation of leucocytes with f-MLP (1.0μmol/l) caused a net increase in release of basophil histamine, but was associated with only a transient net increase in release of [3H]purine in four of five experiments. Immunoglobulin E-dependent stimulation produced basophil histamine release in the absence of detectable [3H]purine release.
6. These data demonstrate that leucocytes can be stimulated to release adenosine and related nucleoside matabolites accompanying the release of basophil-derived histamine. As adenosine is a bronchoconstrictor in asthma and leucocyte infiltration of the airways is a characteristic feature of the disease, leucocyte-derived adenosine may contribute to the pathogenesis of airways obstruction.
Renal prostaglandins in cirrhosis of the liver
Authors: Guarner C. , Colina I. , Guarner F. , Corzo J. , Prieto J. , Vilardell F. 
Published: August 2015

1. Urinary prostaglandin excretion was studied in 42 patients with liver cirrhosis and in nine control subjects on restricted sodium intake and on bed rest. Creatinine clearance (CCr), sodium excretion (UNaV), plasma renin activity (PRA) and plasma aldosterone were also evaluated.
2. Patients without ascites and ascitic patients without renal failure showed increased urinary excretion of immunoreactive 6-ketoprostaglandin F1α (i6-keto-PGF1α), prostaglandin E2 (iPGE2) and thromboxane B2 (iTXB2) when compared with controls, while immunoreactive PGF2α (iPGF2α) levels did not differ from those in the control group. Patients with functional renal failure (FRF) presented a significant reduction of vasodilator prostaglandins but urinary excretion of iTXB2 was higher than in controls.
3. On the whole, cirrhotic patients with higher urinary excretion of prostaglandins had normal or nearly normal PRA and aldosterone levels. i6-keto-PGF1α and iPGE2 inversely correlated with PRA and aldosterone.
4. The relationship between i6-ketoPGF1α and CCr was found to be highly significant in cirrhotic patients but not in the control group. On the other hand, iPGE2 significantly correlated with UNaV and with the fractional excretion of sodium (FENa).
5. We concluded that: (a) enhanced renal prostaglandin synthesis in cirrhosis, inversely related to PRA and aldosterone, may be dependent on volume status; and (b) preserved renal function in these patients is associated with the ability to synthesize prostacyclin and PGE2.
Differences in age-independent effects of blood pressure on baroreflex sensitivity between normal and hypertensive subjects
Authors: Shimada Kazuyuki , Kitazumi Tadao , Ogura Hisakazu , Sadakane Noriko , Ozawa Toshio 
Published: August 2015

1. Inter-relationship between age, systolic blood pressure and baroreflex sensitivity index derived from the Valsalva manoeuvre was investigated in either combined or separated groups of normal and hypertensive subjects.
2. Both in the total population as a whole and in each blood pressure subgroup, the baroreflex sensitivity index was significantly inversely related to age and to systolic blood pressure. Furthermore, age was significantly related to systolic blood pressure except in the hypertensive group.
3. Partial correlation analysis showed that, in the total and hypertensive population, the baroreflex sensitivity index was significantly related to age and systolic blood pressure independently of each other variable. In the normal group, however, the baroreflex sensitivity index was not related to systolic blood pressure after adjusting for the effect of age, but remained significantly related to age independently of systolic blood pressure. The estimates of relative effects of the two variables on baroreflex sensitivity by multiple regression analysis were consistent with these results.
4. Thus a prevailing concept of the inhibitory effect of blood pressure on baroreflex function may be accurate exclusively in hypertensive patients, and baroreflex function appears to be more sensitive to age-related changes in this system than to those related to blood pressure level, particularly in non-hypertensive normal subjects.
Stimulus-induced release of endogenous catecholamines from human washed platelets
Authors: Smith C. C. T. , Wilson A. P. , Prichard B. N. C. , Betteridge D. J. 
Published: August 2015

1. Using high-performance liquid chromatography with electrochemical detection, we have studied the release of endogenous catecholamines from washed platelets induced to aggregate by ADP and thrombin.
2. Washed platelets exhibit irreversible aggregation with 10 μmol/l ADP and 0.3 unit of thrombin/ml, extents of aggregation being 27% and 76% respectively.
3. ADP (10μmol/l) increased noradrenaline release to the medium by 20% and adrenaline by 28%. As observed with aggregation, 0.3 unit of thrombin/ml produced a more marked effect on release than ADP, noradrenaline and adrenaline being increased by 570% and 169% respectively.
4. Values for platelet noradrenaline content were found to mirror those for the release from platelets induced by thrombin.
5. A correlation was observed between catecholamine release and the concentration of thrombin present in incubations. These data reflect the changes observed with platelet aggregation.
6. This is the first study to determine catecholamine release from platelets by direct measurement. Local catecholamine release after platelet aggregation in vivo may have important consequences for tissue perfusion.
Effect of serum from patients with essential hypertension on sodium transport in normal leucocytes
Authors: Gray H. H. , Hilton P. J. , Richardson P. J. 
Published: August 2015

1. This study has confirmed that serum from patients with essential hypertension inhibits sodium transport and elevates intracellular sodium in normal human leucocytes in vitro when compared with that of well matched normotensive controls.
2. The magnitude of this effect was positively correlated with the diastolic blood pressure of the hypertensive patient.
3. The degree of sodium transport inhibition conferred by the hypertensive's serum was correlated with the abnormal sodium transport in the hypertensive's own leucocytes.
4. These results confirm the presence of a serum inhibitor of sodium transport in essential hypertension. The relationship between the inhibitory effect and severity of hypertension argues that it may be of mechanistic importance.
Effect of guar on second-meal glucose tolerance in normal man
Authors: Trinick T. R. , Laker M. F. , Johnston D. G. , Keir M. , Buchanan K. D. , Alberti K. G. M. M. 
Published: August 2015

1. Whole body glucose turnover and absorption of a 50 g glucose drink was studied in six healthy volunteers on two occasions, 4 h after a ‘breakfast’ of 50 g of glucose, mixed on one occasion with 20 g of guar gum.
2. Plasma glucose concentrations were significantly reduced with guar gum compared with those obtained without guar gum (P &lt; 0.0001).
3. Whole body glucose turnover studied by an intravenous primed dose constant infusion technique using d-[3-3H]glucose showed no significant difference between the two groups: 353 ± 15 mmol with guar and 350 ± 9 mmol without guar.
4. Total oral glucose absorption, followed with a D-[1-14C]glucose tracer, was significantly decreased by guar treatment, being 219 ± 3 mmol with guar and 239 ± 5 mmol without guar (P &lt; 0.05).
5. Serum insulin levels were lowered by guar treatment (P&lt;0.05) while those of C-peptide, gastric inhibitory polypeptide, glucagon, Cortisol and pancreatic polypeptide did not differ significantly.
6. Blood lactate concentrations were raised in the guar treated group (P &lt; 0.05) whereas pyruvate, alanine, glycerol and 3-hydroxybutyrate concentrations did not differ significantly.
7. These results support the suggestion that guar improves second-meal tolerance to glucose by decreasing absorption.
Cytoplasmic free [Ca2+] is not increased in the platelets of deoxycorticosterone–salt and spontaneously hypertensive rats
Authors: Murakawa Koh-Ichi , Kanayama Yoshiharu , Kohno Masakazu , Kawarabayashi Takahiko , Yasunari Kenichi , Takeda Tadanao , Hyono Atsushi 
Published: August 2015

1. The cytoplasmic free calcium concentration ([Ca2+]i) in the platelets of spontaneously hypertensive rats (SHR), Wistar–Kyoto rats (WKY), deoxycorticosterone–salt hypertensive rats (DOC) and normotensive Sprague–Dawley rats (SD) was measured with the fluorescent dye, quin-2-tetra-acetoxymethyl ester.
2. No significant difference in platelet [Ca2+]i was found between SHR and WKY or between DOC and SD rats.
3. No correlations were found between systolic blood pressure and [Ca2+]i.
4. These results suggest that the elevation of platelet [Ca2+]i does not necessarily accompany hypertension in rats.
Selective effects of graft-versus-host reaction on disaccharidase expression by mouse jejunal enterocytes
Authors: Lund E. K. , Bruce M. G. , Smith M. W. , Ferguson A. 
Published: August 2015

1. Graft-versus-host reaction (GvHR) was induced in neonatal mice to produce crypt hyperplasia with and without stunted villi. Lactase activity was measured along individual villi of control and GvHR mice using quantitative cytochemistry.
2. Lactase activity increased in control mice as enterocytes migrated over the lower part of the villus. This increase was followed by a period when lactase activity remained approximately constant.
3. Effects produced by GvHR on this normal profile of development included an extension of the distance on the villus over which enterocytes could continue to increase lactase activity, a reduction in the time needed for an enterocyte to express lactase activity at maximal rate, and an overall decrease in the maximal lactase activity expressed by mature enterocytes.
4. These effects have been quantified by fitting logistic curves to the experimental data.
5. Parallel biochemical analyses of intestinal homogenates showed sucrase, isomaltase, trehalase and maltase activities to increase markedly 7–8 days after the injection of parental spleen cells.
6. Attention is drawn to similarities between these results and steroid induced precocious development of intestinal function in neonatal mice.
Infused salbutamol accentuates acid-induced lung injury in the rat
Authors: Braude Stanley , Royston David 
Published: August 2015

1. The effect in the rat of salbutamol infusion (1 μg min−1 kg−1) on acid-induced lung injury has been determined. Severity of lung injury was assessed by two techniques: the pulmonary clearance of 99mTc-diethylenetriaminepenta-acetate (99mTc-DTPA) and the lung wet/dry weight ratio, giving indices of alveolar epithelial permeability and transendothelial water filtration respectively.
2. Mean half-time of clearance of 99mTc-DTPA was increased significantly in rats who had intratracheal acid-induced injury and control (saline) intravenous infusion (19.4 ± 2.6 min) compared with non-acid-treated rats (98.1 ± 7.2) (P &lt; 0.0001). However, those animals who had intratracheal acid injury and subsequent salbutamol intravenous infusion had significantly faster clearance (11.5 ± 1.9) than the acid and control infusion group (P &lt; 0.05).
3. Gravimetric lung water in the acid-only rats (expressed as wet/dry weight ratio) was increased significantly (6.4 ± 0.3) compared with the non-acid-treated controls (5.4 ± 0.2) (P &lt; 0.01). Acid-treated rats who had salbutamol infused had dramatically increased lung water (10.0 ± 0.6) (P &lt; 0.001 vs acid and control infusion).
4. Intravenous salbutamol infusion itself produced no significant difference in the results for both techniques, compared with the non-acid-treated time-course controls.
5. Infused salbutamol accentuates acid-induced lung injury in the rat. Possible factors responsible for these findings include β2-adrenergic agonist mediated inhibition of hypoxic pulmonary vasoconstriction (HPV) and a predominant β1-adrenergic agonist inotropic effect of salbutamol with resultant rise in pulmonary artery pressure.
An improved approach for the determination of plasma [3H]noradrenaline kinetics using high-performance liquid chromatography
Authors: Howes L. G. , MacGilchrist A. , Hawksby C. , Sumner D. , Reid J. L. 
Published: August 2015

1. An improved approach for the determination of plasma [3H]noradrenaline ([3H]NA) kinetics in man is described, incorporating the extraction of plasma [3H]catechols on alumina and separation of [3H]NA from [3H]dihydroxymetabolites by high-performance liquid chromatography (HPLC).
2. After a 30 min intravenous infusion, [3H]NA accounted for 57.2 ± 13.2% of the radioactivity recovered by the procedure, while the dihydroxymetabolites 3,4-[3H]dihydroxyphenylethylene glycol ([3H]DHPG) and 3,4-[3H]dihydroxymandelic acid ([3H]DOMA) accounted for 32.3 ± 11.5% and 4.9 ± 6.0% respectively. After 90 min of constant infusion the proportion due to [3H]NA fell to 44.4 ± 10.4%, while that due to [3H]DHPG rose to 45.9 ± 9.5% because of an increase in the amount of [3H]DHPG at the later time.
3. Plasma [3H]NA radioactivity rose rapidly during the constant infusion and usually reached a plateau by 30 min. However, in individual subjects large variations in plasma [3H]NA radioactivity occurred during the course of the infusion, implying rapid and variable changes in plasma [3H]NA clearance.
4. The inclusion of a step to separate [3H]NA from [3H]dihydroxymetabolites is necessary if the aim is to determine plasma [3H]NA kinetics, as a large proportion of the radioactivity recovered from plasma on alumina is due to the presence of these metabolites.
Humoral hypercalcaemia of malignancy: Report of two further patients with biochemical studies on tumour extracts
Authors: Seshadri M. S. , Mason R. S. , Cornish C. J. , Pryke A. M. , Posen S. 
Published: August 2015

1. Tumour extracts from two patients with humoral hypercalcaemia of malignancy contained material which stimulated adenylate cyclase in chick renal membranes and in rat osteosarcoma cells.
2. Adenylate cyclase-stimulating activity in each system was inhibited by a specific parathyroid hormone (PTH) antagonist.
3. Studies in two HPLC systems suggested that the adenylate cyclase-stimulating factors extracted from these tumours differed from each other and from synthetic human parathyroid hormone 1–34.
4. The presence of similar PTH-like adenylate cyclase stimulating material(s) in oncogenic osteomalacia suggests that adenylate cyclase stimulating factor(s) may not be the direct or the sole cause of hypercalcaemia.
Muscle metabolism in patients with peripheral vascular disease investigated by 31P nuclear magnetic resonance spectroscopy
Authors: Hands L. J. , Bore P. J. , Galloway G. , Morris P. J. , Radda G. K. 
Published: August 2015

1. Eleven men with claudication and ten control subjects had calf muscle metabolism studied at rest and during exercise and the subsequent recovery period by 31P nuclear magnetic resonance (n.m.r.) spectroscopy.
2. The muscle of patients with severe claudication had a significantly greater depletion of phosphocreatine and fall in pH during exercise and a slower recovery of phosphocreatine and pH after exercise.
3. The muscle of patients with both mild and severe disease had slower rates of ADP recovery after exercise than that of control subjects.
4. Surgical correction of the associated arterial stenosis abolished claudication and led to correction of the metabolic abnormalities in two patients.
5. Claudication pain was not related to intracellular pH or concentration of phosphorus-containing metabolites.
6. Energy production via oxidative metabolism is impaired but glycolysis may be increased in the calf muscle of patients with intermittent claudication.
Neurogenic hyperacute ascites in mice
Authors: Nelson David P. , Robin Eugene D. , Wong Ronald J. , Morin Mark E. , Bensch Klaus G. , Murphy Brian J. , Theodore James 
Published: August 2015

1. Four groups of mice were subjected to controlled fatal head trauma and then evaluated for the presence of ascites (neurogenic hyperacute ascites, NHA). The animals died virtually instantaneously and without evidence of maintained pain or suffering. The volume of ascites was determined in one group of animals. Two of the traumatized groups were pretreated, one with the β-blocker propranolol and the other with the α-blocker phentolamine. A fifth, non-traumatized, group which was killed with ether inhalation served as a control group. Two more groups of non-traumatized mice were administered either the α-adrenergic agonist methoxamine hydrochloride or the β-agonist isoethrane mesylate before killing by ether inhalation, and then evaluated for ascites.
2. Transudative ascitic fluid was found in 87–100% of untreated traumatized mice and in no control animals. Pretreatment with phentolamine had no effect on the prevalence of ascites. Pretreatment with propranolol produced a significant decrease in the prevalence of ascites compared with trauma alone (P &lt; 0.001). Isoethrane (β-agonist) administration caused ascites in 100% of the treated animals. Methoxamine (α-agonist) administration did not cause ascites.
3. A previously undescribed consequence of acute brain trauma is described (NHA) which appears to be mediated by β-sympathetic activity of central origin. NHA is inhibited by β-blockade and can be simulated with β-agonist administration.
Parathyroidectomy, cardiovascular reactivity and calcium distribution in aorta and heart of spontaneously hypertensive rats
Authors: Schleiffer R. , Pernot F. , Gairard A. 
Published: August 2015

1. In order to elucidate the mechanisms by which parathyroidectomy (PTX), performed in young spontaneously hypertensive rats (SHR), delays the development and attenuates the level of hypertension, we studied, in vivo, cardiovascular reactivity (CVR, blood pressure response to bolus noradrenaline administration), aortic calcium distribution and cardiac calcium content in SHR with or without parathyroid glands.
2. PTX was performed in 6-week-old animals and experiments were done in pretreated anaesthetized animals 2 and 22 weeks after surgery. A significantly decreased CVR was observed 22 weeks after PTX in SHR-PTX as compared with controls.
3. These data are not specific for hypertensive animals since similar data are also obtained on nor-motensive Wistar rats treated in an identical fashion. In addition, after PTX in SHR and Wistar rats myocardial (auricle and ventricle) calcium content was more rapidly reduced (after 2 weeks) than aortic membrane-bound and cellular calcium fractions.
4. The present studies established that PTX decreases CVR and alters calcium content and distribution in the cardiovascular systems of rats from hypertensive and normotensive strains. Furthermore, the results confirm a requirement for the parathyroid glands in the pathogenesis of spontaneous hypertension in SHR and for the normal CVR.