bluuebunny/crossref_metadata_2025_split huggingface dataset:
Platelet-Activating Factor Mediates Pancreatic Function Derangement in Caerulein-Induced Pancreatitis in Rats
Authors: Alonso Ricardo , Montero Angel , Arévalo Miguel , García Luis J. , Sánchez-Vicente Concepción , Rodríguez-Nodal Fernando , López-NOVOA José M , Calvo José J. 
Published: August 2015

1. We have assessed the role of platelet-activating factor in caerulein-induced acute pancreatitis (four subcutaneous injections of caerulein at a dose of 20 μg/kg) by measuring platelet-activating factor levels in portal blood, pancreatic tissue and peritoneal exudate in rats with and without pancreatitis.
2. We have also observed the effect of the platelet-activating factor antagonist, BN-52021, on the hyper-amylasaemia and exocrine pancreatic secretion impairment associated with pancreatitis.
3. In rats with pancreatitis the basal pancreatic flow rate was increased (1.63 ± 0.41 versus 0.25 ± 0.03 μl/min). Total protein output was similar in both untreated (5.98 ± 1.93 μg/min) and caerulein-injected (6.5 ± 2.0 μg/min) animals. Amylase output was lower in rats with pancreatitis (19.6 ± 4.8 μ-units/min) than in controls (39.4 ± 16.6 μ-units/min).
4. Caerulein-treated animals had significantly higher serum amylase levels than untreated animals. BN-52021 significantly reduced the caerulein-induced hyperamylasaemia.
5. Portal blood platelet-activating factor levels increased in rats with pancreatitis and in rats infused with cholecystokinin. Rats injected with caerulein and BN-52021 had portal blood levels of platelet-activating factor that were lower than those with pancreatitis.
6. Morphological derangements associated with pancreatitis (inflammatory infiltration and cell vacuolization) were also markedly reduced in BN-52021-treated animals.
7. The results of this study suggest that platelet-activating factor is involved in the development of caerulein-induced acute pancreatitis in rats.
Comparison of Stable Isotopes and Radioisotopes in the Measurement of Iron Absorption in Healthy Women
Authors: Barrett Jon F. R. , Whittaker Paul G , Fenwick John D. , Williams John G. , Lind Tom 
Published: August 2015

1. Stable isotope methods are being used to investigate the absorption of dietary iron. In order to be certain that this new methodology is accurate, we have compared results obtained using stable isotopes and inductively coupled plasma mass spectrometry with those determined using a radioisotope and whole body counting.
2. The stable isotope 54Fe (2.8 mg) was given to 10 healthy non-pregnant women. Six women received the isotope in aqueous form, and four took it with a meat meal. The 54Fe served as a carrier for 10 ng of the radioisotope 59Fe. An ampoule (200 μg) of the isotope 57Fe or 58Fe was then given intravenously, and in serum samples taken over the next 10 h the ratios of the stable iron isotopes were measured by inductively coupled plasma mass spectrometry and the oral iron absorption was calculated. This was then compared with the results obtained by using a whole body counter to measure (on day 0 and day 14) the γ-activity emitted by the radioisotope.
3. The mean iron absorption measured by both methods ranged from 8% to 45%. Measurement of the post-absorptive serum enrichment of the stable isotopes provided estimates of absorption from both aqueous and food iron which were similar to that yielded by whole body counting, the mean difference being −1.5% (95% confidence interval −5.2 to 2.1%). Absorption estimated by stable isotopes exhibited the same inverse relationship with the serum ferritin level (body iron stores) to that known to exist with whole body counting. Similar estimates of food iron absorption were obtained irrespective of the type of isotope used as an extrinsic label, implying that stable isotopes are as valid as radioisotopes in reflecting intrinsic food iron absorption.
4. This study validates the use of stable isotopes and post-absorption curves as a new and accurate technique in the measurement of iron absorption.
Signal Variance Electrocardiogram: A Test for Early Detection of Myocardial Involvement in Cystic Fibrosis?
Authors: Freyschuss Ulla , Hjelte Lena , Johannesson Marie , Nowak Jacek , Sylvén Christer 
Published: August 2015

1. Variance electrocardiography is a new resting procedure for the detection of ischaemia-induced variability in the electrical expression of the depolarization phase. The analysis is performed on 220 cardiac cycles using high-fidelity ECG signals from 24 leads, and the electrical variability is expressed as an electrical variability index ranging from 1 to 150. In this study, variance electrocardiography was employed to detect cardiac involvement in 23 patients with cystic fibrosis.
2. Patients with cystic fibrosis presented a significantly higher mean electrical variability index than control subjects, and their index values correlated inversely with the arterial oxygen partial pressure and forced expiratory volume in 1.0 s. Patients with a high electrical variability index (&gt; 75) displayed a lower clinical score (Shwachman score) and a longer duration of chronic colonization with Pseudomonas aeruginosa. Patients with conduction disturbances and patients with echocardiographic right ventricular pathology presented higher indices than those without.
3. Electrical variability index is increased in cystic fibrosis and correlates with other signs of cardiac and pulmonary derangement. Variance electrocardiography may therefore have the potential to be a sensitive and simple method for monitoring cardiac involvement in this disease.
Renal Effects of Local Infusion of Adenosine in Man
Authors: Edlund Anders , Ohlsén Hans , Sollevi Alf 
Published: August 2015

1. The effects of local intra-arterial infusion of adenosine on renal blood flow, glomerular filtration and renin release in eight healthy awake subjects have been examined.
2. Renal blood flow and glomerular filtration rate were measured as the clearances of p-aminohippurate and inulin, respectively. After basal samplings, adenosine was infused intra-arterially at successive rates of 2 and 10 μg min−1 kg−1 for 40 min at each rate.
3. Apart from a small increase in heart rate (65 ± 4 to 71 ± 4 beats/min), there were no signs of sympathetic activation (unchanged blood pressure and catecholamine levels) during the infusion. Clearance of p-aminohippurate tended to increase, but not significantly, during adenosine infusion (518 ± 48 ml/min basal, 563 ± 52 ml/min during the highest dose of adenosine). The arterial plasma concentration of p-aminohippurate decreased by 9 ± 3% (P &lt; 0.05), consistent with a small increase in renal blood flow in the infused kidney. Inulin clearance was reduced from 115 ± 3 to 97 ± 2 ml/min (P &lt;0.001). The extraction of inulin, reflecting the filtration fraction, was 18% in both kidneys in the basal state. During infusion of adenosine the extraction in the infused kidney decreased to 12 ± 3% (P &lt; 0.01 compared with the control kidney, 23 ± 3%).
4. The total excretion of Na+ was unchanged, but there was a minor decrease in K+ clearance. Thus, the K+/Na+ excretion ratio decreased from a basal value of 13 ± 2 to 10 ± 2 (P &lt;0.01) at the highest dose of adenosine. The calculated renal uptake of oxygen was unchanged in the control kidney, but decreased in the adenosine-infused kidney from a basal value of 5.4 ± 0.5 ml/min to 3.8 ± 0.4 ml/min at the highest dose of adenosine (P &lt; 0.01).
5. During continued intra-arterial adenosine infusion, nitroprusside was infused (0.3-2.5 μg min−1 kg−1) for 15 min to decrease blood pressure and stimulate renin production. Mean blood pressure decreased from 90 ± 2 to 63 ± 2 mmHg, whereas heart rate remained unaffected. There were increases in the arterial concentrations of adrenaline (0.3 ± 0.1 to 1.3 ± 0.3 nmol/l; P&lt;0.01), aldosterone (136 ± 24 to 491 ± 144 pmol/l; P&lt;0.001) and renin activity (0.8 ± 0.2 to 1.8 ± 0.5 pmol) of angiotensin I h−1 min−1; P &lt; 0.05; values correspond to the basal state and 15 min of nitroprusside infusion, respectively). In the control kidney the arteriovenous concentration difference for renin activity increased from the basal state by 2.3 ± 0.8 pmol of angiotensin I h−1 ml−1, but remained unchanged in the adenosine-infused kidney (0.0 ± 0.3 pmol of angiotensin I h−1 ml−1, P &lt; 0.02).
6. In conclusion, the direct renal effects of adenosine in healthy awake subjects include a local dilatation of postglomerular vessels, thereby decreasing glomerular filtration, and a reduction in renal oxygen consumption. Furthermore, adenosine prevents an increase in renin release during nitroprusside-induced hypotension.
Ventilatory and Heart Rate Responses after Exercise in Chronic Cardiac Failure
Authors: Riley M. , Stanford C. F. , Nicholls D. P. 
Published: August 2015

1. To determine if the recovery period after exercise is abnormal in chronic cardiac failure, we studied 15 patients with stable chronic cardiac failure, and 14 normal subjects during and after symptom-limited maximal treadmill exercise.
2. In patients, O2 consumption fell exponentially from 16.8 (13.7-20.0) ml min−1 kg−1 at peak exercise to 6.0 (5.2-6.7) ml min−1 kg−1 at 3 min of recovery and in control subjects it fell from 30.2 (27.0-33.5) ml min−1 kg−1 to 6.7 (5.9-7.4) ml min−1 kg−1 (mean and 95% confidence intervals). The associated decay constants were slower in patients [0.70 (0.58-0.83) min−1 versus 0.93 (0.81-1.05) min−1 in control subjects (P &lt; 0.01, t-test)].
3. CO2 consumption kinetics displayed similar abnormalities [(k: 0.55 (0.41-0.69) min−1 versus 0.71 (0.59-0.83) min−1, P &lt; 0.05)] and heart rate kinetics showed a similar trend [(k: 0.53 (0.33-0.74) min−1 versus 0.76 (0.62-0.89) min−1, P = 0.08].
4. We conclude that patients with cardiac failure recover more slowly from exercise than normal subjects, and that this may further impair their ability to perform exercise, with consequent effect on quality of life.
Pressure-Diuresis-Natriuresis Response in Hyperthyroid and Hypothyroid Rats
Authors: Vargas Félix , Atucha Noemí M. , Sabio J. Mario , Quesada Tomás , García-Estañ Joaquín 
Published: August 2015

1. Renal responses to changes in renal perfusion pressure were studied in anaesthetized hyperthyroid (thyroxine, 300 μg day−1 kg−1) and hypothyroid (methimazole, 0.03% via drinking water) rats to determine whether an abnormality in the pressure-diuresis-natriuresis phenomenon is involved in the resetting of kidney function in these disorders.
2. There were no significant differences between control and hypothyroid rats with respect to the relationships between renal perfusion pressure and absolute or fractional water and sodium excretion. However, in hyperthyroid rats the pressure-diuresis-natriuresis mechanism was impaired.
3. Renal blood flow and glomerular filtration rate were well autoregulated and there were no differences between control and hypothyroid rats at every level of renal perfusion pressure. A significantly lower glomerular filtration rate was observed in hyperthyroid rats when data were expressed per gram kidney weight, but glomerular filtration rate was similar to that of control rats when normalized by body weight.
4. The shift in the pressure-diuresis-natriuresis response of hyperthyroid rats is mainly due to an increase in tubular reabsorption. Blunting of the renal pressure-diuresis-natriuresis mechanism in hyperthyroid rats may represent the functional resetting of the kidney necessary for sustained hypertension. However, a normal pressure-natriuresis response was observed in hypothyroid rats, in which blood pressure was markedly reduced.
Role for Endothelin in the Renal Responses to Radiocontrast Media in the Rat
Authors: Oldroyd S. , Slee S.-J. , Haylor J. , Morcos S. K. , Wilson C. 
Published: August 2015

1. The involvement of endothelin in the renal responses to radiocontrast media was examined in the rat in vitro and in vivo using BQ123, a selective endothelin (ETA) receptor antagonist, and phosphoramidon, an endothelin-converting enzyme inhibitor.
2. For experiments in vitro, an isolated perfused rat kidney was employed perfusing in closed circuit with an albumin-based Krebs-Henseleit solution. The effects of BQ123 and phosphoramidon on the renal responses to iotrolan (iso-osmolar radiocontrast media) and diatrizoate (high-osmolar radiocontrast media) were examined. In vivo, renal conductance was measured using a Doppler flow probe in the anaesthetized rat pretreated with indomethacin, and the effects of BQ123 and phosphoramidon on the renal response to intravenous diatrizoate were examined.
3. In vitro, iotrolan and diatrizoate both produced a biphasic effect on the glomerular filtration rate, characterized by a transient increase followed by a sustained fall. Pretreatment with BQ123 (10 μmol/l), but not phosphoramidon (1 mmol/l), prevented both the increase and the sustained fall in glomerular filtration rate induced by radiocontrast media.
4. In vitro, iotrolan and diatrizoate both produced a sustained fall in renal perfusate flow. An initial increase in renal perfusate flow was only observed with diatrizoate. Pretreatment with BQ123 (10 μmol/l), but not with phosphoramidon (1 mmol/l), markedly inhibited the sustained fall in renal perfusate flow produced by both iotrolan and diatrizoate. BQ123 (10 μmol/l), however, markedly potentiated the renal vasodilatation produced by diatrizoate.
5. In vivo, in the anaesthetized rat treated with indomethacin, the sustained fall in renal conductance produced by diatrizoate (2.9 g of iodine/kg, intravenously) was markedly inhibited by pretreatment with BQ123 (1 mg/kg) but not with phosphoramidon (10 mg/kg).
6. A role for endothelin as a mediator of the renal responses of radiocontrast media is proposed.
A Comparison of Bone Mineral Density between Caucasian, Asian and Afro-Caribbean Women
Authors: Tobias J. H. , Cook D. G. , Chambers T. J. , Dalzell N. 
Published: August 2015

1. We analysed the lumbar spine (L2-L4) and femoral neck bone mineral density results of Caucasian (n = 2232), Asian (Indian sub-continent) (n = 153) and Afro-Caribbean (n = 102) women referred for bone densitometry over a 30 month period. To assess the risk of osteoporosis, the results of Caucasian and Asian women were compared with those of a reference Caucasian population supplied by Lunar.
2. Subject characteristics were similar in all three groups, other than expected ethnic differences in stature and weight. We found that lumbar spine and femoral neck bone mineral density in Caucasians was lower than in Afro-Caribbeans, but higher than in Asians. Consistent with this, bone mineral density was also lower in Asians as compared with the reference Caucasian population, both at the lumbar spine and femoral neck. As a consequence, a higher proportion of Asian women were classified as being at increased risk of osteoporosis than Caucasian women.
3. Since ethnic differences in skeletal size might influence bone mineral density, we also obtained values for bone mineral content in Caucasian and Asian women that were corrected for projected skeletal area, and weight and years since menopause, using regression equations derived from the Caucasian study population. After this analysis, the difference in bone mineral content between Caucasians and Asians at the lumbar spine disappeared, while that at the femoral neck persisted.
4. We conclude that the assessment of risk of osteoporosis in Asian women by comparing bone mineral density with a reference Caucasian population may have limited validity because of the influence of skeletal size on such measurements.
Bone Density and Mineral Metabolism in Thyroidectomized Patients Treated with Long-Term l-Thyroxine
Authors: Giannini Sandro , Nobile Martino , Sartori Leonardo , Binotto Pierluigi , Ciuffreda Matteo , Gemo Giancarlo , Pelizzo Maria Rosa , D'Angelo Angela , Crepaldi Gaetano 
Published: August 2015

1. A decreased bone mass has been reported in patients with endogenous hyperthyroidism, but the effect on bone density and mineral metabolism of thyroxine administration in thyroidectomized patients is still controversial. To further contribute to this debate, we studied 25 women thyroidectomized for thyroid cancer on long-term treatment with thyroid-stimulating hormone-suppressive doses of L-thyroxine. Twenty-one sex- and age-matched normal subjects were also studied as a control group.
2. The bone density of the spine and serum calcitonin, calcitriol and parathyroid hormone concentrations were not different when the whole patient group was compared with the control subjects, nor when the patients and control subjects were compared according to their menopausal status. However, postmenopausal thyroidectomized patients showed significantly lower bone mass (P &lt; 0.001) than premenopausal patients.
3. L-Thyroxine-treated patients showed significantly higher levels of bone alkaline phosphatase and urine hydroxyproline excretion than control subjects (P &lt; 0.003 and P &lt; 0.001, respectively). These differences were still present when patients and control subjects were analysed according to their menopausal status. However, bone alkaline phosphatase was significantly higher in postmenopausal than in premenopausal women only in L-thyroxine-treated patients (P &lt; 0.05). In postmenopausal L-thyroxine-treated patients a negative correlation between time since menopause and bone mass (P &lt; 0.05) and a positive correlation between bone alkaline phosphatase and hydroxyproline excretion (P &lt; 0.03) were also found.
4. We conclude that long-term thyroid-stimulating hormone-suppressive treatment with L-thyroxine in thyroidectomized women is not associated with a decrease in spinal bone mass nor with calcitonin deficiency, and that L-thyroxine treatment may increase skeletal sensitivity to menopause-related bone loss.
Prolonged Changes in Protein and Amino Acid Metabolism after Zymosan Treatment in Rats
Authors: Rooyackers Olav E. , Saris Wim H. M. , Soeters Peter B. , Wagenmakers Anton J. M. 
Published: August 2015

1. Intraperitoneal injections of zymosan were given to rats, according to a modified procedure, in order to create a pattern of illness with an acute critical phase for 36 h followed by a prolonged recovery phase lasting for at least 10 days. Changes in amino acid and protein metabolism were studied in both phases.
2. Differences between this modified and the original zymosan model are a lower mortality (16%), which is limited to the first 36 critical hours, and the absence of signs of severe illness during the prolonged recovery phase.
3. Wasting of muscle protein and decreased protein synthesis rates in muscle were observed during the acute phase of illness. Liver size and liver protein synthesis rates were increased during the same period. The decrease in the total amount of muscle protein and the increase in liver weight were still present 12 days after zymosan treatment, despite a normalization of protein synthesis rates. Large decreases were observed in the concentrations of the conditionally essential amino acids glutamine and arginine in muscle over 6 days. Decreases in plasma glutamine and arginine on day 12 after zymosan indicated that the rats were still not fully recovered on this day.
4. We conclude that injection of a single dose of zymosan in rats leads to metabolic derangements both during the acute phase of critical illness and during the prolonged recovery phase. The model seems suited for investigating the biochemical mechanisms behind these metabolic derangements and for studying therapeutic and nutritional interventions during recovery from critical illness.
An Angiotensin Converting Enzyme Inhibitor, Perindopril, Prevents Progression of Preformed Atherosclerotic Lesions in the Cholesterol-Fed Rabbit
Authors: Fennessy Paul A. , Campbell Julie H. , Campbell Gordon R. 
Published: August 2015

1. The aim was to determine whether the angiotensin converting enzyme inhibitor perindopril, at a concentration approaching that used in human antihypertensive therapy, influences progression of preformed atherosclerotic plaques.
2. Rabbits had their right carotid artery de-endothelialized with a balloon catheter, which resulted in the formation of a myointimal thickening.
3. At 14 weeks post surgery groups I, II and III (n = 6 per group) were fed a 1% cholesterol-enriched diet for 6 weeks, then group I rabbits were sacrificed. Groups II and III were placed on a normolipidaemic diet for a further 6 weeks with group III rabbits also receiving 0.3 mg day−1 kg−1 perindopril. Groups IV and V were treated the same as groups II and III, respectively, except that they received a normal diet throughout.
4. Group I rabbits fed a 1% cholesterol-enriched diet for 6 weeks developed lipid-filled lesions covering 26.3 ± 14.3% of the surface area of the descending thoracic aorta. This was exacerbated in rabbits fed a 1% cholesterol diet for 6 weeks followed by 6 weeks on a normal diet (61.2 ± 27.3%). In rabbits fed a 1% cholesterol diet for 6 weeks then a normal diet for a further 6 weeks plus 0.3 mg day−1 kg−1 perindopril, the percentage surface area covered by lesions was 21.8 ± 15.8%. No lesions developed in the aortas of rabbits fed a normal diet. In the right coronary artery the resulting neointima in rabbits fed a 1% cholesterol diet for 6 weeks only was 42.4 ± 5.7% of the cross-sectional area of the vessel wall, 57.4 ± 8.0% in rabbits receiving 6 weeks' cholesterol diet then 6 weeks' normal diet, 36.0 ± 6.6% in rabbits fed a 6-week cholesterol diet then 6 weeks' normal diet with 0.3 mg day−1 kg−1 perindopril and 33.2 ± 4.9% and 31.8 ± 3.1% in rabbits on a normal diet throughout with 0 and 0.3 mg day−1 kg−1 perindopril respectively. The cellular composition of the lesions was also altered in perindopril-treated animals, with fewer and smaller fat-filled cells surrounded by more extracellular matrix.
5. Perindopril is effective in preventing progression of existing atherosclerotic lesions in the cholesterol-fed rabbit after 6 weeks on a normal diet.
Effects of Fasting on Fatty Acid Kinetics and on the Cardiovascular, Thermogenic and Metabolic Responses to the Glucose Clamp
Authors: Webber J. , Taylor J. , Greathead H. , Dawson J. , Buttery P. J. , Macdonald I. A. 
Published: August 2015

1. The effects of fasting for 12, 36 and 72 h were examined in 19 normal subjects. Each subject was studied before and during a euglycaemic (4 mmol/l) hyperinsulinaemic (100 m-units min−1 m−2) clamp. Measurements were made of palmitate turnover and oxidation, glucose disposal, thermogenesis, intermediary metabolites and cardiovascular variables.
2. Basal respiratory exchange ratio fell from 0.78 ± 0.01 to 0.75 ± 0.01 to 0.72 ± 0.01 with fasting (P &lt; 0.001). In response to the clamp it rose to 0.91 ± 0.02, 0.83 ± 0.01 and 0.77 ± 0.01 after 12, 36 and 72 h respectively. Metabolic rate rose during the clamp by 0.41 ± 0.06, 0.11 ± 0.03 and 0.14 ± 0.04 kJ/min respectively (P &lt; 0.001 for 36- and 72-h values versus that at 12 h).
3. Fasting reduced total insulin-mediated glucose disposal rates from 42.6 ± 2.5, to 31.0 ± 1.8 to 21.3 ± 1.5 μmol min−1 kg−1 body weight after 12, 36 and 72h respectively (P &lt; 0.001). Glucose oxidation fell from 16.9 ± 1.1 to 8.7 ± 1.7 to 0.2 ± 1.3 μmol min−1kg−1 body weight over the same period (P &lt; 0.001). Non-oxidative glucose disposal rates did not change significantly.
4. Basal plasma palmitate turnover increased with duration of fasting, being 1.16 ± 0.08, 1.72 ± 0.17 and 2.30 ± 0.35 μmol min−1 kg−1 body weight. In response to the clamp, palmitate turnover fell to 0.42 ± 0.05, 0.69 ± 0.08 and 1.28 ± 0.45μmol min−1 kg−1 body weight. Plasma palmitate oxidation was 0.58 ± 0.04, 0.75 ± 0.06 and 1.13 ± 0.11 μmol min−1 kg−1 body weight basally, and fell to 0.16 ± 0.02, 0.28 ± 0.04 and 0.43 ± 0.13 μmol min−1 kg−1 body weight by the end of the clamp. The proportion of total lipid oxidation represented by plasma non-essential fatty acid oxidation was not affected by fasting, but fell in response to the clamp.
5. Fasting caused a progressive resistance to the effects of insulin and glucose on oxidative glucose disposal and on forearm glucose uptake. Insulin-mediated glucose storage was unaffected by fasting, but the apparent cost of this storage was reduced by fasting.