bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Nifedipine during Low, Normal and High Intakes of Sodium in Patients with Essential Hypertension
Authors: Valdés Gloria , Soto M. Eugenia , Croxatto Hector R. , Bellolio Teresa , Corbalán Ramón , Casanegra Pablo 
Published: August 2015

1. Nifedipine (20 mg) was given by mouth to seven patients with moderate essential hypertension receiving a low, normal or high sodium intake. The drug produced an important hypotensive effect. Normal sodium intake enhanced the hypotensive action of the drug compared with that during the low and high sodium regimens. Blood pressure remained significantly lower 3 h after drug ingestion.
2. Increases in heart rate and plasma renin activity under all conditions reflected enhanced adrenergic activity.
3. A short-term natriuresis followed nifedipine ingestion in spite of increased aldosterone excretion during the low sodium diet and a decrease in urinary kallikrein during the low and high sodium diets.
4. Nifedipine increased urinary volume only during the high sodium intake.
5. Apart from vasodilatation, nifedipine induces important changes in neurogenic, renal and adrenal mechanisms that regulate blood pressure homoeostasis. Different conditions of sodium balance modulate most of these effects.
Preferential Desensitization to Cardiovascular β2-Adrenoceptor Stimulation in Patients with Peripheral Autonomic Neuropathy after Treatment with Pindolol
Authors: Veld A. J. Man In 'T , Vincent H. H. , Schalekamp M. A. D. H. 
Published: August 2015

1. Three patients with orthostatic hypotension due to peripheral autonomic neuropathy were studied. The diagnosis was based on severe hypotension during 60° head-up tilting and absence of the systolic pressure overshoot in phase IV of the Valsalva response. There was no clinical evidence for central nervous system involvement. Plasma noradrenaline levels were 50 and 90 pg/ml in two patients and below 25 pg/ml in one. Noradrenaline was unresponsive to head-up tilting. Heart rate did not change after atropine (2 mg intravenously) in two patients and it increased from 62 to 118 beats/min in the remaining patient after 1 mg. Thus the three patients had a peripheral sympathetic lesion which was accompanied with an efferent para-sympathetic lesion in two.
2. Infusion of isoprenaline in these patients showed supersensitivity for the chronotropic and vascular effects of this drug. Similar cardiac and vascular supersensitivity was observed for salbutamol. Cardiac chronotropic supersensitivity to prenalterol was less pronounced as compared with isoprenaline and salbutamol. The patients were treated with pindolol, 15 mg daily, divided in three doses. After 4 weeks' treatment pindolol was stopped and the infusions of isoprenaline and salbutamol were repeated 72 h after the last dose of pindolol (5 mg). The isoprenaline dose-heart rate response curve was shifted to the right by a factor of 10. The salbutamol dose-heart rate response curve was shifted by a factor of 45, whereas the prenalterol dose-heart rate response curve was shifted by a factor of only 3.
3. The observed chronotropic effects of salbutamol provide evidence for the existence of cardiac β2-adrenoceptors in man. Comparison of the cardiovascular responses after the non-selective β-adrenoceptor agonist isoprenaline, the β2-selective agonist salbutamol and the β1-selective agonist prenalterol suggests preferential β2-adrenoceptor sensitization in chronic autonomic failure, which can be reversed by treatment with the non-selective partial β-adrenoceptor agonist pindolol.
Myocardial Exchanges of Glutamate, Alanine and Citrate in Controls and Patients with Coronary Artery Disease
Authors: Thomassen A. R. , Nielsen T. T. , Bagger J. P. , Henningsen P. 
Published: August 2015

1. Myocardial exchanges of plasma alanine, glutamate, citrate, lactate, glucose and free fatty acids were determined in 17 patients with coronary artery disease and in seven control subjects during rest, atrial pacing and recovery.
2. Myocardial release of alanine was demonstrated in all subjects. The amount released was higher in patients with coronary artery disease than in controls. In the patients alanine release was related to severity of coronary artery stenosis.
3. All subjects showed myocardial uptake of glutamate, higher in patients than in controls at rest and during recovery. During atrial pacing myocardial glutamate extraction remained unchanged in controls but decreased in patients.
4. Citrate was released by the heart in all controls and patients. During recovery citrate output was higher in patients than in controls.
5. Myocardial alanine and citrate release during recovery were positively correlated. Both were positively related to myocardial uptake of glutamate during recovery and to the decrease in glutamate extraction during pacing.
6. The results indicate changed myocardial citrate and amino acid metabolism in coronary artery disease. Measurement of myocardial exchanges of glutamate, alanine and citrate in addition to lactate is suggested as a sensitive biochemical test in assessing myocardial ischaemia in man.
Glucose Turnover and Indices of Recycling in Thyrotoxicosis and Primary Thyroid Failure
Authors: McCulloch A. J. , Nosadini R. , Pernet A. , Piniewska M. , Cook D. B. , Clark F. , Johnston D. G. , Alberti K. G. M. M. 
Published: August 2015

1. Glucose turnover was examined by using simultaneous bolus intravenous tracer administration of both [3-3H]glucose and [1-14C]glucose in hyperthyroid and hypothyroid subjects before and during appropriate therapy and in matched controls.
2. In hyperthyroid subjects, total glucose turnover (as indicated by analysis of decay of [3-3H]glucose specific radioactivity) was increased (18.1 ± 1.0 vs 12.4 ± 0.9 μnol kg−1 min−1, P &lt; 0.01), as was the metabolic clearance rate for glucose (3.5 ± 0.3 vs 2.4 ± 0.2 ml kg−1 min−1, P &lt; 0.01).
3. Glucose turnover rates determined with [1-14C]glucose as tracer were lower than total glucose turnover rates in all subjects. This difference represents an index of recycling of the 14C label between glucose and glucose-derived C3 intermediates.
4. The recycling index was increased in hyperthyroidism both in amount (4.7 ± 0.6 vs 1.3 ± 0.3 μmol kg−1 min−1, P &lt; 0.001) and when expressed as a percentage of total glucose turnover (27 ± 3 vs 10 ± 2%, P &lt; 0.001).
5. Turnover rates determined by [1-14C]glucose represent irreversible glucose disposal and were similar in hyperthyroid and control subjects (hyperthyroid 13.4 ± 1.1 vs control 11.2 ± 0.9 μmol kg−1 min−1). The major fraction of the increase in total glucose turnover could thus be accounted for by increased cycling of glucose.
6. Total glucose turnover, metabolic clearance and indices of recycling returned to normal with treatment of hyperthyroidism.
7. In hypothyroidism, total glucose turnover (hypothyroid 8.2 ± 0.3 vs control 11.7 ± 1.2 μmol kg−1 min−1, P &lt; 0.01) and metabolic clearance (hypothyroid 1.6 ± 0.1 vs control 2.3 ± 0.2 ml kg−1 min−1, P &lt; 0.001) were decreased and returned to normal with thyroxine therapy. Indices of glucose recycling were normal.
Effect of Aldosterone on the Human Erythrocyte Sodium-Potassium Pump in vitro
Authors: Stern N. , Beck F. , Sowers J. 
Published: August 2015

1. The effects of aldosterone in vitro on the Na+,K+-dependent ATPase activity of isolated human erythrocyte membranes and on rubidium (86Rb) uptake and [3H]ouabain binding of intact erythrocytes were studied.
2. ATPase activity was nearly doubled (0.061 ± 0.006 to 0.110 ± 0.01 μmol of Pl h−1 mg−1 of protein) by the addition of a physiological concentration of aldosterone (2.7 × 10-10 mol/l). Higher concentrations had no greater effect.
3. Aldosterone had no significant effect on 86Rb uptake or [3H]ouabain binding.
4. Erythrocytes contain aldosterone at concentrations similar to that in plasma. The effect of aldosterone on ATPase is probably maximal.
Platelet α2-Adrenergic Receptors in Treated and Untreated Essential Hypertension
Authors: Motulsky Harvey J. , O'Connor Daniel T. , Insel Paul A. 
Published: August 2015

1. One hypothesis to account for altered adrenergic response in hypertensive patients is alteration in adrenergic receptors on responsive cells. We therefore used radioligand binding methods to examine the α2-adrenergic receptors on platelets isolated from 17 normal men and from 19 men with essential hypertension. in these studies we used the α2-selective radioligand [3H]yohimbine to determine receptor number and affinity on intact platelets.
2. The median number of receptors per platelet was 265 for the hypertensive patients versus 246 for the platelets of controls. Likewise there was no difference between hypertensives and controls in the dissociation constant of the receptors for [3H]yohimbine or adrenaline.
3. Anti-hypertensive treatment with the α2-agonist guanabenz or the β-antagonist propranolol did not change the number or affinity of platelet α2-receptors.
4. in untreated hypertensives the receptor number did not correlate with age, blood pressure, or 24 h urinary excretion of catecholamines or Na+.
5. We conclude that neither hypertension nor anti-hypertensive treatment alters the number of α2-adrenergic receptors on human platelets. Furthermore, because therapy with an α2-agonist does not alter the receptor number and because the receptor number did not correlate with urinary excretion of catecholamines (an index of sympathetic-nervous-system activity), we conclude that ‘down-regulation’ of human platelet α2-adrenergic receptors may not readily occur in vivo.
Elevated Arterial Cyclic AMP Levels during the Onset of Renal Hypertension in Rats
Authors: Chatelain Ricardo Exequiel 
Published: August 2015

1. To determine the possible role of arterial cyclic AMP in the pathogenesis of hypertensive vascular hypertrophy and hyperplasia, the changes in the level of this nucleotide were studied during the development of renal hypertension in rats with aortic ligation between the renal arteries.
2. A twofold increase in the cyclic AMP level of the thoracic aorta was observed in 9-day hypertensive rats when compared with sham-operated controls. At this time the total amounts of DNA and collagen were unchanged, although a marked increase in arterial fibrous protein was already present.
3. Arterial cyclic AMP remained significantly elevated in the thoracic aorta of 30-day hypertensive animals. At this time the hypertensive vascular alterations had reached completion as shown by the abnormal accumulation of collagen, DNA and non-fibrous protein.
4. Contrary to the events taking place in the thoracic aorta, a marked decrease in cyclic AMP was present in the abdominal portion, which was protected from high blood pressure by the aortic ligature. in this segment decreased cyclic AMP coexisted with an unchanged collagen content and a diminution in the contents of DNA and non-fibrous protein.
5. Thus a marked increase in arterial cyclic AMP precedes the initiation of DNA replication and collagen accumulation in vascular territories subjected to high blood pressure. These studies suggest the participation of this nucleotide in the vascular growth induced by hypertension.
Trans-Mucosal Passage of Intact Peptides in the Guinea-Pig Small Intestine in Vivo: A Re-Appraisal
Authors: Gardner Michael L. G. , Lindblad Bo S. , Burston David , Matthews David M. 
Published: August 2015

1. Re-examination of data for the chemical analysis of peptide-bound amino acids in the mesenteric venous blood of anaesthetized guinea-pigs suggests that there are small, but significant, amounts of small peptides in the blood of fasted animals.
2. Furthermore, there is a significant increase in the peptide content of the mesenteric venous blood during intraduodenal infusion of a partial digest of casein.
3. The data are consistent with the view that some 10% of the amino nitrogen entering the mesenteric blood during absorption of a casein digest in vivo may be in the form of small peptides, although it is not possible to define confidence limits for this estimate.
Effect of pH, Viscosity and Ionic-Strength Changes on Ciliary Beating Frequency of Human Bronchial Explants
Authors: Luk Chun Ka , Dulfano Mauricio J. 
Published: August 2015

1. Ciliary activity is significantly influenced by chemical and physical properties of the liquid medium in which the cilia beat.
2. We studied the effect of changes in pH, ionic strength and viscosity on the ciliary beat frequency (CBF) of explants of human respiratory mucosa.
3. Optimal CBF was elicited at pH 7.0-9.0, with a marked reduction of CBF outside these limits. The CBF was well preserved at NaCl concentrations between 5 g/l (80 mmol/l) and 12 g/l (200 mmol/l), but there was rapid loss at concentrations below 0.5 gA (10 mmol/l). The cilia beat best at viscosities below 1.0 centipoises (1 mN s m−2). Increase of the viscosity gradually decreases CBF with a significant drop at viscosities above 87 millipoises.
4. It is concluded that the above limits may fairly accurately indicate the actual physical characteristics of the periciliary environment (‘sol layer’) in vivo.
The Effect of Phenylephrine upon Arterial Pressure, Carotid Sinus Radius and Baroreflex Sensitivity in the Conscious Greyhound
Authors: Peveler R. C. , Bergel D. H. , Robinson J. L. , Sleight P. 
Published: August 2015

1. A method for recording carotid sinus diameter in conscious dogs has been developed, using an ultrasound transit time technique. We have used this method to measure the distensibility of the carotid sinus in resting animals, and we have investigated the effect of injecting the vasoactive drug phenylephrine on the mechanical behaviour of the sinus wall.
2. Baroreflex sensitivity was measured in the dogs by the usual method of relating the slowing of the heart to the transient pressure rise induced by the injections of phenylephrine.
3. We have shown that phenylephrine directly reduces the radius of the carotid sinus during the measurements of baroreflex sensitivity. At a dose of 2–4 μg/kg, phenylephrine has an enhancing effect on the baroreflex response, possibly resulting from a modification of baroreceptor output.
Role of Impaired Inspiratory Muscle Function in Limiting the Ventilatory Response to Carbon Dioxide in Chronic Airflow Obstruction
Authors: Gribbin H. R. , Gardiner I. T. , Heinz G. J. , Gibson G. J. , Pride N. B. 
Published: August 2015

1. Twenty patients with severe chronic airflow obstruction (CAFO), four of whom were hypercapnic, had greatly reduced ventilatory responses to rebreathing CO2 under hyperoxic conditions, compared with the responses in normal subjects.
2. Mouth occlusion pressure (P0.1) responses to CO2 were also reduced in the patients compared with those of normal subjects but the reduction was less severe than in the ventilatory response.
3. in ten patients with CAFO minimum pleural pressure during tidal breathing [Ppl min. (dynamic)] at a Pco2 of 8.0 kPa was only slightly less negative than in the normal subjects (−16.2 cm water vs −23.4 cm water).
4. During rebreathing end-expiratory volume (EEV) fell progressively in the normal subjects (mean fall = 800 ml); in the patients there was a progressive rise in EEV (mean rise = 390 ml).
5. When Ppl min. (dynamic) was compared with minimum static pleural pressures at the same lung volume the patients were generating a much higher proportion of their available static pressure (47.0%) than the normal subjects (26.4%) at a Pco2 of 8.0 kPa, suggesting that despite the slightly less negative Ppl min. (dynamic), inspiratory muscle activation was greater in the patients than in normal subjects. Similar conclusions were reached from an analysis of the inspiratory work of breathing.
6. We conclude that hyperinflation, by impairing the capacity of the inspiratory muscles to lower pleural pressure, reduces the ventilatory response to CO2 and adds to the effects of abnormalities in pulmonary mechanics so that measurements of absolute pleural pressure or work of breathing underestimate inspiratory muscle activation in patients with severe CAFO.
7. Hyperinflation and severe airflow obstruction also reduce the change in P0.1 for a given degree of inspiratory muscle activation.
8. Our results suggest that, despite the impaired pressure and ventilatory response to rebreathing CO2 in the patients, their central respiratory drive was greater than that of the normal subjects.
Testing for Autonomic Neuropathy: Heart Rate Changes after Orthostatic Manoeuvres and Static Muscle Contractions
Authors: Wieling W. , Borst C. , Van Brederode J. F. M. , Van Dongen Torman M. A. , Van Montfrans G. A. , Dunning A. J. 
Published: August 2015

1. The initial heart rate (HR) response evoked by standing, 70° head-up tilt, handgrip and contraction of abdominal and leg muscles was analysed in diabetic patients with autonomic neuropathy and in matched controls.
2. in healthy subjects standing induced an immediate, large, HR increase lasting 20 s that far exceeded the small HR rise induced by tilt. The HR response with handgrip and to contraction of abdominal and leg muscles was strikingly similar for the first 5 s to the HR increase after standing.
3. in diabetic patients handgrip and standing induced a small HR increase starting after 2–3 s. Contraction of abdominal and leg muscles evoked little or no HR changes. The HR rise after tilt up was delayed by 10 s compared with healthy controls.
4. It is concluded that the circulatory response to active and passive changes of posture differs fundamentally. Standing and handgrip are superior to head-up tilt as a test for vagal HR control. An abrupt and large HR increase after standing excludes cardiac parasympathetic neuropathy. A modified response, however, may be due to afferent as well as to efferent lesions, e.g. in muscle afferents or in vagal afferents from cardiopulmonary receptors.
Influence of Muscle Wasting on Oral Glucose Tolerance Testing
Authors: Moxley Richard T. , Griggs Robert C. , Forbes Gilbert B. , Goldblatt David , Donohoe Katherine 
Published: August 2015

1. The effect of muscle wasting on glucose tolerance was studied. Oral glucose tolerance testing was performed in three groups of wasted patients: myotonic dystrophy (11); amyotrophic lateral sclerosis (10); other lower motor neuron disease (four). Normal subjects (11) and non-wasted neurological disease (five) controls were studied for comparison. An average decrease of 29–36% in lean body mass was present in the wasted individuals.
2. A slightly higher plasma glucose occurred at 120 min after glucose ingestion in wasted compared with non-wasted individuals (119.2 ± 5 vs 99.9 ± 4 mg/100 ml, P &lt; 0.05).
3. Normal insulin release was seen in all patient groups except those with myotonic dystrophy, who displayed marked hyperinsulinaemia from 30 to 240 min after glucose. This excessive insulin output was not due to a greater absolute decrease in lean body mass in the myotonic dystrophy patients than in the other wasted subjects. No significant correlation between the cumulative insulin release or peak insulin values and the absolute or height adjusted lean body mass was noted within any of the wasted or non-wasted groups.
4. in contrast to the findings of many studies, only clinically insignificant glucose intolerance was detected in ambulatory wasted patients and only patients with myotonic dystrophy had abnormal insulin release. Muscle loss appeared to exert only a slight influence on glucose regulation in these wasted patients and no typical effect of muscular atrophy on pancreatic insulin release was noted.
The Effects of Human Milk and Low-Protein Formulae on the Rates of Total Body Protein Turnover and Urinary 3-Methyl-Histidine Excretion of Preterm Infants
Authors: Pencharz P. B. , Farri L. , Papageorgiou A. 
Published: August 2015

1. The effects of human milk and two low-protein formulae on the protein metabolism of 30 preterm appropriate for gestational age infants, birth weight 1.5-2.0 kg, were studied. The compositions of the two formulae were identical except for the protein source, with either casein or whey predominant.
2. The three diet groups all received similar nitrogen (390 mg of N day−1 kg−1) and energy intakes (500 kJ day−1 kg−1).
3. Growth rates for length and weight were comparable and approximated to intrauterine growth. Nitrogen absorption and net nitrogen utilization were enhanced in the human-milk-fed group. However, there were no differences in nitrogen retention, which averaged 274 mg day−1 kg−1 and approximated to intrauterine accretion rates.
4. Rates of whole-body nitrogen flux, protein synthesis and breakdown in the human-milk group were increased by 43–54% over the values seen in either of the two formula-fed groups (P &lt; 0.01). No differences were seen between the two formula groups.
5. No differences were seen in urine 3-methylhistidine excretion between the three study groups.
6. Our results suggest significant differences in the whole-body protein metabolism of formula-fed infants compared with human-milk-fed infants.
Growth Characteristics of α-Foetoprotein-Secreting Human Hepatocellular Carcinoma in Athymic (Nude) Mice
Authors: Bassendine M. F. , Wright N. A. , Thomas H. C. , Sherlock S. 
Published: August 2015

1. The growth characteristics of a human hepatocellular carcinoma, derived from the PLC/PRF/5 cell-line (‘Alexander’), transplanted into sub-lethally irradiated athymic (nu/nu) mice have been examined. The xenograft re-expresses α-foetoprotein production although this tumour marker was not detected during cell culture in vitro.
2. There is a positive correlation between serum α-foetoprotein concentration and tumour mass (r = 0.978), validating the use of this tumour marker to assess growth.
3. in mice with progressively growing xenografts there is a linear correlation between log serum α-foetoprotein concentration and time, compatible with exponential tumour growth. Growth of the human hepatocellular carcinoma xenograft is rapid, with an α-foetoprotein doubling time of 6.1 ± 2.1 days (±standard deviation) and a mass doubling time of 3.6 ± 1.2 days (±standard deviation).
4. The tumour cell birth or production rate, determined by a stathmokinetic (metaphase arrest) technique using vincristine, is 15.7 ± 3.8 (95% confidence limits) cells per 1000 cells per hour. The tumour cell loss factor (49%) is low and may contribute to the rapid growth of this human hepatocellular carcinoma xenograft.
A Radioimmunoassay for α-and β-Gliadins
Authors: Ciclitira P. J. , Lennox E. S. 
Published: August 2015

1. A rapid, sensitive specific radioimmunoassay for α- and β-gliadin has been developed using an antiserum raised in rabbits to A-gliadin, a component of α-gliadin.
2. The antigen used in the assay was α-gliadin labelled with 125I; antigen-antibody complexes were collected after adsorption to Staphylococcus aureus in suspension.
3. The sensitivity of the assay, as judged by competitive binding with unlabelled antigen, was 1 ng of α- or β-gliadin, which show complete cross-reaction with this antiserum.
4. Cross-reactivity to other wheat proteins was &lt; 1% and no cross-reactivity to extracts of rye, barley or oats was observed.
5. This radioimmunoassay for α- and β-gliadin has been used to measure their amount in different varieties of wheat flour, several foods prepared from flour, e.g. bread, biscuits and products prepared as ‘gluten free’. The possibility of assaying for α-gliadin in prepared foods is of special value since α-, β-, γ- and ω-gliadin have been shown to exacerbate coeliac disease.