bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of undernutrition on thermoregulation in the elderly
Authors: Fellows I. W. , Macdonald I. A. , Bennett T. , Allison S. P. 
Published: August 2015

1. With use of a liquid-conditioned coverall, the thermoregulatory responses to a lowering of environmental temperature from 35°C to 23°C were assessed in eight normally nourished and six undernourished elderly female patients, during their convalescence after surgical repair of a fracture of the femoral neck.
2. There was no difference in the peripheral vasoconstriction of the two groups in response to a cold environment.
3. On lowering the environmental temperature, the increase in metabolic rate was significantly impaired in the undernourished group compared with the normally nourished group (P &lt; 0.05).
4. There was a small decrease in core temperature in the undernourished group (median change −0.1°C) during the period of exposure to the lowest environmental temperature (23°C). This was significantly different from the lack of change (median change 0°C) in core temperature observed in the normally nourished group (P &lt; 0.05).
5. This defect of thermogenesis may underlie the propensity of undernourished elderly patients to suffer hypothermia and fracture of the femoral neck in the winter months.
Variability of the haemodynamic responses to laboratory tests employed in assessment of neural cardiovascular regulation in man
Authors: Parati Gianfranco , Pomidossi Guido , Ramirez Agustin , Cesana Bruno , Mancia Giuseppe 
Published: August 2015

1. In man evaluation of neural cardiovascular regulation makes use of a variety of tests which address the excitatory and reflex inhibitory neural influences that control circulation. Because interpretation of these tests is largely based on the magnitude of the elicited haemodynamic responses, their reproducibility in any given subject is critical.
2. In 39 subjects with continuous blood pressure (intra-arterial catheter) and heart rate monitoring we measured (i) the blood pressure and heart rate rises during hand-grip and cold-pressor test, (ii) the heart rate changes occurring during baroreceptor stimulation and deactivation by injection of phenylephrine and trinitroglycerine, and (iii) the heart rate and blood pressure changes occurring with alteration in carotid baroreceptor activity by a neck chamber. Each test was carefully standardized and performed at 30 min intervals for a total of six times in each subject.
3. The results showed that the responses to any test were clearly different from one another and that this occurred in all subjects studied. For the group as a whole the average response variability (coefficient of variation) ranged from 10.2% for the blood pressure response to carotid baroreceptor stimulation to 44.2% for the heart rate response to cold-pressor test. The variability of the responses was not related to basal blood pressure or heart rate, nor to the temporal sequence of the test performance.
4. Thus tests employed for studying neural cardiovascular control in man produce responses whose reproducibility is limited. This phenomenon may make it more difficult to define the response magnitude typical of each subject, as well as its comparison in different conditions and diseases.
Na+ leak in erythrocytes from essential hypertensive patients
Authors: Garay Ricardo P. , Nazaret Corinne 
Published: August 2015

1. Ouabain- and bumetanide-resistant (OBR) Na+ efflux from human erythrocytes into a Mg2+-sucrose medium exhibits kinetic properties consistent with a transmembrane Na+ leak.
2. In 52 essential hypertensive patients, the rate constant of Na+ leak (ke) was 15.0 ± 2.9 × 10−3h−1 (mean ±sd). This was significantly higher than the ke in 47 normotensive controls (13.2 ± 1.6 × 10−3h−1; t = 3.81, P &lt; 0.001; Mann-Whitney U rank sum test P = 0.0014). The relatively small number of patients studied was insufficient to decide if the hypertensive population was bi-modally distributed. Nevertheless, if the upper end of the normotensive population is used as a cutoff point, it appears that a subgroup of 12 hypertensive patients had an increased Na+ leak, ke = 19.5 ± 1.9 × 10−3 h−1 (mean±sd). The increased Na+ leak remained constant in repeated determinations over several months.
3. Na+ movements catalysed by the Na+-K+ co-transport and Na+-Li+ countertransport systems were measured in the above 52 hypertensive patients. Seventeen hypertensive patients showed a low apparent affinity of the co-transport system for internal Na+ and 12 exhibited a high maximal rate of Na+-Li+ countertransport. None of these two abnormalities was found in the 12 hypertensive patients with increased ke. We propose to denote them as Leak-(+) hypertensive patients.
4. Passive net Na+ entry was abnormally high in all Leak-(+) hypertensive patients. However, erythrocyte Na+ content was increased in only five of the 12 Leak-(+) hypertensive patients. A normal or even decreased Na+ content was associated with the presence of compensatory increases in the maximal rate of the Na+-K+ pump and the Na+-K+ co-transport system.
Evidence against a role for superoxide ions in the injury of nephrotoxic nephritis in rats
Authors: Webb D. B. , Mackenzie R. , Zoob S. N. , Rees A. J. 
Published: August 2015

1. The accelerated model of nephrotoxic serum nephritis (NTSN) was produced in 12 Sprague-Dawley rats. Six of these rats were administered superoxide dismutase (EC 1.15.1.1; SOD) subcutaneously (8 mg/kg) 8-hourly for 4 days. The first dose was given 6 h before the nephrotoxic serum (NTS).
2. The progression of renal disease was monitored by following (i) albumin excretion, (ii) serum creatinine and creatinine clearance and (iii) renal histopathology and immunofluorescence.
3. There was no evidence that SOD influences the course of NTSN.
4. SOD was scarcely excreted by control rats or rats with NTSN.
Hepatic lactate uptake is enhanced by low pH at low lactate concentrations in perfused rat liver
Authors: Sestoft Leif , Marshall Michael O. 
Published: August 2015

1. The effect of pH on lactate uptake was studied in perfused liver of rats starved for 48 h.
2. At both low pH (6.8) and normal pH (7.4) lactate uptake was a linear function of lactate concentration in input medium in the range 0.4–1.5 mmol/l.
2. In the lower concentration range (0.4–0.8 mmol/l) the rate of lactate uptake was 30% higher at pH 6.8 than at pH 7.4.
4. At pH 6.8 lactate uptake was independent of whether Pco2 was 2.7 or 5.3 kPa.
5. We suggest the increased rate of lactate uptake at low pH and concentrations lower than 0.8 mmol/l was due to the stimulatory effect of H+ on the lactate carrier.
Biochemical evidence for an increased and progressive deposition of collagen in lungs of patients with pulmonary fibrosis
Authors: Kirk Jacqueline M. E. , Da Costa P. E. , Turner-Warwick Margaret , Littleton R. J. , Laurent G. J. 
Published: August 2015

1. To assess the role of changes in lung collagen in pulmonary fibrosis, the content of this protein was measured in biopsy and autopsy lung from patients with cryptogenic fibrosing alveolitis (CFA), a fibrotic lung disorder of unknown cause.
2. The collagen concentration was measured in lung samples from 21 patients with CFA (14 autopsy and seven open-lung biopsy) and 17 normal subjects; total lung collagen was determined in the right lung of 10 patients who died from CFA and the results were compared with those from 10 normal lungs.
3. There was a wide variation in the collagen concentrations but the mean value (±sem) for patients with CFA (217±13mg/g dry weight) was significantly higher (P &lt; 0.02) than that of the controls (155 ± 15mg/g dry weight). The mean collagen concentration of the autopsy samples (243 ± 20 mg/g dry weight) was significantly higher (P &lt; 0.05) than that of the biopsy samples (165 ± 24 mg/g dry weight).
4. The mean total collagen was markedly raised (P &lt; 0.001) in right lungs of patients with CFA (32.5 ± 4.3g) compared with normal lungs (14.0 ± 1.1g). When corrected for the predicted lung volume this difference in total lung collagen remained statistically significant (P &lt; 0.01, mean for patients 4.7 ± 0.7 mg/ml, controls 2.3 ± 0.2 mg/ml).
5. These results demonstrate an increased deposition of lung collagen in this form of pulmonary fibrosis. They also suggest that there is a greater collagen concentration in lungs of patients with later disease, indicating a progressive deposition of collagen during the course of the disease.
A microcalorimetric study of heat production in resting skeletal muscle from human subjects
Authors: Fagher B. , Monti M. , Wadsö I. 
Published: August 2015

1. Different microcalorimetric techniques have been compared for the assessment in vitro of the total metabolic activity of resting skeletal muscle. Human fibre bundles were suspended in Krebs-Ringer-phosphate buffer containing glucose and insulin and the heat evolution was continuously monitored for 2–6 h. Palmitate as substrate was also tested.
2. The power signals declined rapidly when a static calorimetric method (A) was used. Two different perfusion methods (B, C) gave higher power values. Long-lasting steady states were observed with method C, where the sample was contained in a cage acting as a stirrer.
3. Significant differences were found for fibre bundles from different human muscles as well as age- and sex-related differences. The heat production in samples from the rectus abdominis muscle (method B), 0.73 mW/g muscle wet wt., was significantly higher than for the obliquus internus muscle, 0.44 mW/g, and the vastus lateralis muscle, 0.55 mW/g, but not different from the heat production value of vastus medialis, 0.66 mW/g.
4. In method C particularly, the fibre bundles are believed to be in adequate contact with the surrounding medium. With the use of a multichannel calorimeter it is possible to perform up to four experiments simultaneously, e.g. involving the calorigenic effects of pharmacological substances. The technique provides a new approach for detailed studies of muscle metabolism in physiological and pathological conditions.
Atrial natriuretic peptide: an endogenous factor enhancing sodium excretion in man
Authors: Anderson John , Struthers Allan , Christofides Nic , Bloom Stephen 
Published: August 2015

1. For many years experimental evidence has suggested the existence of a circulating factor able to enhance sodium excretion.
2. Very recently peptides with natriuretic activity in experimental animals have been isolated from mammalian and human cardiac tissue. In order to determine whether this natriuretic activity has relevance to man we have studied the effects of an infusion of α-human atrial natriuretic peptide (α-h-ANP) in normal subjects.
3. Sodium excretion trebled (P = &lt;0.005) during the infusion of a calculated dose of 15 pmol of α-h-ANP min−1 kg−1 and there was an accompanying diuresis; radioimmunoassay of plasma α-h-ANP during the natriuresis indicated a mean peak incremental concentration of 203 ± 78 (sem) pmol/l. The infusion of a calculated dose of 1.5 pmol min−1 kg−1 did not affect sodium excretion.
4. There were no haemodynamic changes and no side effects were noted.
Thermogenesis in human skeletal muscle as measured by direct microcalorimetry and muscle contractile performance during β-adrenoceptor blockade
Authors: Fagher Birger , Liedholm Hans , Monti Mario , Moritz Ulrich 
Published: August 2015

1. The influence of β-adrenoceptor-blockade on skeletal muscle was studied in ten healthy males with propranolol, atenolol and pindolol randomly given for 8 days each in a cross-over double blind test. After 7 days on each drug, muscle function was tested by an isokinetic dynamometer. Thermogenesis in biopsy samples taken from vastus lateralis muscle after a low grade exercise was studied after 8 days on each drug by direct calorimetry with a perfusion microcalorimeter.
2. Before drug administration, a median heat production rate of 0.67 mW/g of muscle was measured. This value was significantly reduced by 25% during propranolol, but no significant change was found during atenolol or pindolol administration.
3. Peak torque decline during isokinetic endurance test changed significantly in knee flexor but not in extensor muscles, from 15% to 27% after propranolol and from 15% to 23% after pindolol. Maximum dynamic strength was unaltered.
4. Our data suggest that blockade of sympathetic β2-receptors decreases thermogenesis in human skeletal muscle and impairs isokinetic endurance.
Neuropeptide Y in renovascular models of hypertension in the rat
Authors: Allen J. M. , Godfrey N. P. , Yeats J. C. , Bing R. F. , Bloom S. R. 
Published: August 2015

1. Neuropeptide Y content of the kidneys, heart, blood vessels, adrenals and brain stem was determined in both two-kidney, one-clip and one-kidney, one-clip Goldblatt hypertension in rats and compared with levels in age- and sex-matched controls.
2. Renal neuropeptide Y content was significantly reduced in the clipped kidney of rats in both Goldblatt two-kidney, one-clip and Goldblatt one-kidney, one-clip models of hypertension. The content of neuropeptide Y was also reduced but to a lesser extent in the contralateral, non-ischaemic kidney in the two-kidney, one-clip model.
3. In both models of hypertension, neuropeptide Y content in the heart was significantly reduced in the left ventricle and septum but unchanged in the atria and right ventricle wall.
4. There was no significant change in the concentration of neuropeptide Y through the vasculature (major arteries and veins), including the renal artery distal to the clip, or in adrenals and brain stem.
Effects of sulindac on renal function and prostaglandin synthesis in patients with moderate chronic renal insufficiency
Authors: Mistry C. D. , Lote C. J. , Gokal R. , Currie W. J. C. , Vandenburg M. , Mallick N. P. 
Published: August 2015

1. The renal effects of therapeutic doses of sulindac were studied in nine patients with stable renal insufficiency, mean creatinine clearance 37.0 ± 2.2 ml min−1 1.73 m−2 (range 24.7–54.6 ml min−1 1.73 m−2).
2. Nine days' treatment with sulindac produced a small, but significant, reduction in the mean creatinine clearance (37.0 ± 2.2 to 34.7 ± 2.2 ml min−1 1.73 m−2; P &lt; 0.02) and 99mTc diethylenetriaminepenta-acetate (DTPA) clearance (35.5 ± 3.4 to 31.4 ± 3.6 ml min−1 1.73 m−2; P &lt; 0.02) without altering body weight, effective renal plasma flow [131I]hippuran clearance), plasma renin activity (PRA), 24 h urinary volume or electrolyte excretion.
3. After discontinuation of sulindac, creatinine clearance returned to pretreatment values.
4. In five female patients, pretreatment urinary excretion of the 6-ketoprostaglandin F1α (6-keto-PGF1α), a stable breakdown product of prostacyclin (PGI2), was significantly reduced (P &lt; 0.02) when compared with four healthy controls, whereas prostaglandin E2 (PGE2) was unchanged. Administration of sulindac did not significantly alter the excretion rate of PGE2 or 6-ketoPGF1α in this group of patients.
5. In chronic renal disease with moderate renal impairment, reduced renal prostacyclin synthesis may be an important predisposing factor to the renal toxicity associated with the use of nonsteroidal anti-inflammatory drugs (NSAID). Short term use of sulindac in therapeutic doses does not appear to influence the excretion of prostaglandins and produces only a minor reversible change in renal function; used cautiously it may have advantages over other NSAID in these patients.-
Dopamine blockade and natriuresis during water immersion in normal man
Authors: Coruzzi P. , Biggi A. , Musiari L. , Ravanetti C. , Vescovi P. P. , Novarini A. 
Published: August 2015

1. Natriuresis was studied during water immersion in eight normal subjects either in the absence or in the presence of dopamine blockade by domperidone.
2. Creatinine clearance showed no significant changes; urine flow remained significantly above control values during water immersion, implying persistent suppression of antidiuretic hormone.
3. The marked natriuresis seen during water immersion alone was significantly blunted (P &lt; 0.05) but not abolished during water immersion plus domperidone.
4. Suppression of the renin–aldosterone system by water immersion alone was not significantly different from that obtained during water immersion plus dopamine blockade.
5. On the contrary, plasma prolactin levels, previously suppressed during water immersion alone, were significantly stimulated during water immersion plus domperidone, thus indirectly suggesting a role of dopamine in mediating the blunted natriuresis seen during water immersion.
Sensory mechanisms in the upper respiratory tract affect the inhalation of cigarette smoke in man
Authors: Grant S. G. N. , Woodman G. , Newman S. P. , Pavia D. , Clarke S. W. 
Published: August 2015

1. Cigarette puffing parameters (puff volume, puff duration, number of puffs, total smoking time) and inhaled smoke volume (by a radiotracer techique) have been measured in a group of 11 asymptomatic smokers, once after topical anaesthesia of the upper airways and once without anaesthesia.
2. Topical anaesthesia significantly reduced the mean inhaled smoke volume per puff for the group from 41.1 ml to 30.6 ml (P &lt; 0.05) and the total inhaled smoke volume from 575 ml to 528 ml (P = 0.05), but cigarette puffing parameters were unchanged.
3. It is concluded that stimulation of upper airway sensory receptors, probably sensitive to nicotine, may be an important mechanism in determining the amount of cigarette smoke inhaled by smokers.
The plasma release of atrial natriuretic peptide in man
Authors: Anderson J. V. , Donckier J. , McKenna W. J. , Bloom S. R. 
Published: August 2015

1. We studied plasma atrial natriuretic peptide (ANP) concentrations in seven normal subjects after the acute intravenous infusion of sodium chloride/potassium chloride solution (saline).
2. Three separate infusions of 6, 12 and 18 ml of saline/kg body weight each significantly increased the circulating concentration of ANP without changes of plasma osmolality or electrolyte concentrations.
3. The mean maximal rise of the plasma ANP concentration after the three saline infusions was significantly correlated (r = 0.74, P &lt; 0.001) with, but occurred 10–30 min later than, the maximal atrial pressure rise.
4. These observations are in accord with the hypotheses that: (a) ANP is a circulating natriuretic factor; (b) atrial distension is an important stimulus to ANP release in man.
Palmitic acid oxidation and incorporation into triglyceride by needle liver biopsy specimens from control subjects and patients with alcoholic fatty liver disease
Authors: Leung N. W. Y. , Peters T. J. 
Published: August 2015

1. A micro-technique was developed to measure fatty acid oxidation in vitro and to investigate its possible derangement in alcoholic fatty liver disease.
2. Percutaneous liver biopsy specimens were obtained from nine control subjects and 28 alcoholic patients with mild to severe fatty liver. Fresh tissue (10–15 mg) was incubated at 37°C for 90 min in a sealed reaction flask containing 1.92 mmol/l [l-14C]palmitic acid (1–2 μCi) and 1% essentially fatty acid free albumin in Krebs-Henseleit buffer, pH 7.4. Radiolabelled CO2 and perchloric acid-soluble ketone bodies were isolated and counted.
3. CO2 production was markedly reduced in alcoholic patients with mild and severe fatty liver compared with controls. This depression was reversed by the addition of malate to the reaction flask but not by carnitine or coenzyme A.
4. Ketone body production was similar in controls and patients with mild and severe fatty liver.
5. After the incubation in vitro, the tissue was extracted with chloroform/methanol and the triglyceride fraction isolated by thin layer chromatography and counted for radioactivity. The rate of palmitic acid incorporation into triglyceride was higher in alcoholic patients, particularly those with severe fatty infiltration, compared with controls.
6. It is suggested that alcoholic fatty liver is accompanied by a progressive reduction in palmitic acid oxidation with the major defect occurring in the tricarboxylic acid cycle. In contrast, the rate of palmitic acid esterification into ‘triglyceride is enhanced.
Effects of thyroid dysfunction on serum calcium in the rat
Authors: Gammage M. D. , Logan S. D. 
Published: August 2015

1. Serum calcium was measured under different circumstances of thyroid dysfunction in male Sprague-Dawley and female Wistar rats.
2. After induction of hypothyroidism with 131I and propylthiouracil, serum calcium fell from a control value of 2.43 ± 0.08 mmol/l to 2.07 ± 0.08 mmol/l (P &lt; 0.01).
3. Thyroid hormone replacement therapy in hypothyroid rats caused a return of serum calcium to control values (2.09 ± 0.04 mmol/l to 2.41 ± 0.02 mmol/l, P &lt; 0.01).
4. Treatment of normal rats with thyroid hormones caused elevation of serum calcium to 2.59 ± 0.04 mmol/l compared with a control value of 2.44 ± 0.02 mmol/l (P &lt; 0.01).
5. Time-course studies demonstrated a slow decline in serum calcium levels over a 10 week period during induction of hypothyroidism with propylthiouracil alone but a very rapid normalization of serum calcium (within 1 h) after replacement therapy with l-tri-iodothyronine.
6. These data illustrate the considerable influence that thyroid hormones exert on calcium metabolism and demonstrate for the first time consistent changes in serum calcium in the rat with hypo- and hyper-thyroidism.
Brown adipose tissue uncoupling protein content in human infants, children and adults
Authors: Lean M. E. J. , James W. P. T. , Jennings G. , Trayhurn P. 
Published: August 2015

1. A solid-phase radioimmunoassay is described for the estimation of the uncoupling protein content of human brown adipose tissue mitochondria, as an index of thermogenic capacity.
2. The concentration of inner mitochondrial membrane uncoupling protein was measured in brown adipose tissue samples from 48 individuals who died suddenly.
3. The uncoupling protein content of axillary adipose tissue was greater than that of perirenal adipose tissue.
4. Variations in brown adipose tissue uncoupling protein content, which would be consistent with changing thermogenic requirements and capacity, were observed in different groups of subjects. Significantly lower concentrations were found in adults and in pre-term and stillborn infants than in older infants and children.
Effect of posture on plasma immunoreactive atrial natriuretic peptide concentrations in man
Authors: Solomon L. R. , Atherton J. C. , Bobinski H. , Green R. 
Published: August 2015

1. The effect of changes of posture on plasma atrial natriuretic peptide concentrations and renal function was studied in normal human volunteers.
2. Plasma atrial natriuretic peptide concentrations increased in the supine posture, reached a maximum value after 30–60 min, remained elevated for 4 h and decreased to baseline values on return to the upright posture. Inflation of antishock trousers, which apply positive pressure to the legs and lower abdomen, attenuated the fall in plasma atrial natriuretic peptide concentration in the upright position.
3. In the supine posture there were increases in urine flow rate, sodium, lithium, fractional sodium and fractional lithium clearances. Fractional distal water and sodium excretion, and total distal water and sodium reabsorption, which were estimated by the lithium clearance technique, also increased.
4. Heart rate and systolic and diastolic blood pressures decreased in the supine and increased on return to the upright posture. Inflation of antishock trousers prevented the increase in heart rate in the upright posture.
5. The contribution of haemodynamic factors to the increase in plasma atrial natriuretic peptide concentrations in the supine position and the relationship between this increase and the associated changes in renal function are discussed. However, the contribution of atrial natriuretic peptide to these changes is uncertain.