bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of the Renal Nerves in Modulating Renin Release During Pressure Reduction at the Feline Kidney
Authors: Johns Edward J. 
Published: August 2015

1. Experiments were undertaken in pentobarbitone-anaesthetized cats to determine how reflex activation of the renal nerves altered the responsiveness of the kidney to release renin during reductions in renal perfusion pressure. Reflex activation of the renal nerves was achieved by reducing carotid sinus perfusion pressure by 30 mmHg, which increased systemic blood pressure. During this period renal perfusion pressure was regulated at control levels and neither renal blood flow nor glomerular filtration rate changed, but there was a significant decrease in sodium excretion and increase in renin secretion. Renal denervation abolished both these latter responses.
2. Renal perfusion pressure reduction, by 25-30 mmHg, had no effect on renal blood flow or glomerular filtration rate but significantly decreased sodium excretion and increased renin secretion. Simultaneous reduction of carotid sinus and renal perfusion pressures had no effect on renal blood flow or glomerular filtration rate, decreased sodium excretion, and the magnitude of the increase in renin secretion was significantly greater than that obtained with reduction in renal perfusion pressure alone. Renal denervation abolished the increase in renin secretion during these manoeuvres.
3. During atenolol administration, renal haemodynamics and sodium excretion responses to renal pressure reduction were similar to those obtained in the absence of the drug. Renin secretion was increased, but significantly less than in the absence of atenolol. Simultaneous carotid sinus and renal pressure reductions during atenolol administration had no effect on renal haemodynamics, reduced sodium excretion and increased renin secretion, the magnitude of which was significantly greater than that recorded with only renal pressure reduction in the presence of atenolol.
4. Direct electrical stimulation of the renal nerves, at frequencies which caused a 5-10% reduction in renal blood flow, did not change glomerular filtration rate, decreased sodium excretion by 30% and increased the rate of renin secretion twofold. In the presence of atenolol, such renal nerve stimulation reduced renal blood flow to the same degree, did not change filtration rate, decreased sodium excretion by 37% but did not change renin secretion.
5. These results show that the magnitude of the release of renin in response to renal pressure reduction is dependent on activity within the renal nerves, being blunted after denervation, and enhanced during reflex activation of the renal nerves.
The effect of Adrenaline upon Cardiovascular and Metabolic Functions in Man
Authors: Fellows I. W. , Bennett T. , Macdonald I. A. 
Published: August 2015

1. On three separate occasions, at least 1 week apart, seven young healthy male subjects received intravenous infusions of either adrenaline, 50 ng min−1 kg−1 (high A), adrenaline, 10 ng min−1 kg−1 (low A) or sodium chloride solution (saline :154 mmol of NaCl/1) plus ascorbic acid, 1 mg/ml (control), over 30 min.
2. Venous adrenaline concentrations of 2.19 ± 0.15 nmol/l, 0.73 ± 0.08 nmol/l and 0.15 ± 0.03 nmol/l were achieved during the high A, low A and control infusions respectively.
3. Heart rate rose significantly by 19 ± 3 beats/min (high A) and by 6 ± 1 beats/min (low A). Heart rate remained significantly elevated 30 min after cessation of the high A infusion, despite venous plasma adrenaline concentration having fallen to control levels.
4. The diastolic blood pressure fell during the high A and low A infusions, but the systolic blood pressure rose only during the high A infusion.
5. Vasodilatation occurred in the calf vascular bed during both high A and low A infusions. The changes in hand blood flow and hand vascular resistance were not statistically significant, although there was a tendency to vasoconstriction during the infusion of adrenaline.
6. Metabolic rate rose significantly by 23.5 ± 1.8% (high A) and by 11.8 ± 1.6% (low A). Metabolic rate remained elevated between 15 and 30 min after termination of the high A infusion. There was an initial transient increase in respiratory exchange ratio (RER) during the adrenaline infusions. During the later stages of the adrenaline infusions and after their cessation, RER fell, probably reflecting increased fat oxidation.
7. Blood glucose, glycerol and lactate concentrations all rose significantly during the high A infusion, but only the blood glycerol concentration rose during the low A infusion. Plasma potassium concentration fell during and after the high A infusion but only after cessation of the low A infusion.
8. When adrenaline was infused intravenously at rates that elevated the plasma adrenaline concentration within the physiological range, peripheral circulatory effects were observed similar to those previously described for larger doses of adrenaline. The persistent tachycardia noted after stopping the high A infusion may, at least in part, have been a consequence of the concomitantly elevated metabolic rate.
The effect of Arginine Vasopressin on Ureagenesis in Isolated rat Hepatocytes
Authors: Drew P. J. T. , Monson J. P. , Metcalfe H. K. , Evans S. J. W. , Iles R. A. , Cohen R. D. 
Published: August 2015

1. The effect of arginine vasopressin (AVP) on ureagenesis was measured in isolated rat hepatocytes with ammonium chloride and l(+)-lactate as substrates.
2. AVP was found to stimulate urea synthesis and the dose-response curve suggests that such an effect is present at concentrations of the hormone as low as 25-50 pmol/l.
3. Both the dose-response curve and the concentrations of NH4+ employed suggest that the effect observed could be of physiological significance.
Human pancreatic and biliary responses to physiological concentrations of cholecystokinin octapeptide
Authors: Anagnostides A. A. , Chadwick V. S. , Selden A. C. , Barr J. , Maton P. N. 
Published: August 2015

1. To determine the functional significance of physiological plasma concentrations of cholecystokinin, five volunteers each received graded doses of intravenous infusions of cholecystokinin octapeptide (CCK-8). At each dose plasma concentrations of CCK-8 were determined and pancreatic and biliary outputs were measured.
2. Threshold plasma concentrations of CCK-8 for augmenting pancreatic trypsin secretion were undetectable (&lt; 3 pmol/l), and maximal trypsin output of 21.9 ± 1.95 k-i.u./30 min was produced by 17.1 ± 6.4 pmol of CCK-8/1. Calculated half-maximal output was produced by 4.7 pmol of CCK-8/1.
3. Maximal trypsin output during infusions of CCK-8 was significantly less than that after a combination of the CCK-like peptide, caerulein, and secretin (32.95 ± 2.16 k-i.u./30 min, P &lt; 0.001).
4. Biliary bile acid and bilirubin outputs were significantly augmented only when plasma concentrations of CCK-8 were &gt; 5 pmol/l.
5. Plasma concentrations of CCK-8 in the low picomolar range exert significant effects on pancreatic and biliary secretion. CCK-8 fulfills the criteria for a circulating hormone.
Intra-individual variability in postural blood pressure in the elderly
Authors: Lipsitz Lewis A. , Storch Helene A. , Minaker Kenneth L. , Rowe John W. 
Published: August 2015

1. Orthostatic hypotension, an age-related phenomenon, has been associated with hypertension and body weight variability. To evaluate the relative contributions of blood pressure elevation and abnormalities in extracellular volume regulation to orthostatic hypotension, elderly institutionalized subjects (mean age = 87 ± 7 years), taking no cardiovascular medications, underwent measurement of body weight (n = 15) and first morning supine and standing blood pressures (n = 19), 12–13 times per subject over a 2–4 week period.
2. There was a wide day-to-day variability in postural systolic blood pressure change (coefficient of variation = 533%) and a strong negative correlation between each day's postural change in systolic blood pressure and basal supine blood pressure (r = −0.55, P &lt; 0.0001).
3. There was no association between postural blood pressure change and heart rate response or body weight changes, which were very small over the duration of the study (coefficient of variation = 0.6%).
4. Elderly individuals have intact homoeostatic mechanisms for the control of standing pressure when basal blood pressure is normal. Postural hypotension in the elderly is a variable phenomenon related to elevations in basal blood pressure.
The characterization and energetic potential of brown adipose tissue in man
Authors: Cunningham S. , Leslie P. , Hopwood D. , Illingworth P. , Jung R. T. , Nicholls D. G. , Peden N. , Rafael J. , Rial E. 
Published: August 2015

1. In adult man, brown fat can be detected in perinephric fat depots by visual inspection, electron microscopy and nucleotide binding to the tissue-specific uncoupling protein.
2. The 32 kDa uncoupling protein is functionally active, showing a nucleotide-sensitive conductance to protons and an uncoupling response to fatty acids.
3. The amount of uncoupling protein in human mitochondria is equivalent to that in a partially cold-adapted guinea pig, indicating some potential for thermogenesis.
4. Respiratory capacity measurements indicate that the total perinephric fat in adult man can only account for one-fivehundredth of the whole-body response to infused noradrenaline. Thus, although brown fat has been found to be quantitatively important in animal studies, considerable caution must be exercised in extrapolating its significance to adult man.
Partial isolation and function of the prostacyclin regulating plasma factor
Authors: Deckmyn H. , Zoja C. , Arnout J. , Todisco A. , Bulcke F. VANDEN , D'hondt L. , Hendrickx N. , Gresele P. , Vermylen J. 
Published: August 2015

1. Rat aortic rings stop producing prostacyclin upon prolonged washing in buffer. This ‘exhaustion’ is caused by inhibition of cyclo-oxygenase, since these rings still convert cyclic endoperoxides but not arachidonic acid into prostacyclin, and most probably is due to high concentrations of peroxides: it can be accelerated by H2O2 or by interrupting the glutathione cycle, while it is delayed by reduced glutathione.
2. Incubation of exhausted rings in human plasma or in a plasma filtrate restores to some extent prostacyclin formation. This filtrate, in particular from uraemic subjects, also inhibits the H2O2 initiated oxidation of guaiacol by ram seminal vesicle microsomes or horseradish peroxidase.
3. The prostacyclin regulating plasma factor has been partially purified and identified as a stable and very polar molecule of mol. wt. 300–400, able to reactivate prostacyclin generation by exhausted rings. We suggest that one or more low mol. wt. plasma components prolong vascular prostacyclin formation by acting as reducing cofactor for cyclo-oxygenase peroxidase.
4. The main physiological role of this plasma activity is probably to protect the vascular prostacyclin forming system from exhaustion during persistent irritation.
Effect of bisphosphonates on prostaglandin synthesis by rat bone cells and mouse calvaria in culture
Authors: Ohya Keiichi , Yamada Shoji , Felix Rolf , Fleisch Herbert 
Published: August 2015

1. Bisphosphonates are potent inhibitors of bone resorption and also inhibit prostaglandin (PG) E2 synthesis in bone cells. Therefore we have investigated whether a correlation exists between inhibition of bone resorption and inhibition of PGE2 formation.
2. Initially, bisphosphonates were tested for their effect on the release of [14C]PGE2 from rat calvaria cells labelled with [14C]arachidonic acid and stimulated by bradykinin, thrombin and mechanical manipulation. The effect on [14C]-PGE2 synthesis was not correlated with the known inhibitory activity of bisphosphonates on bone resorption.
3. Mouse calvaria were then treated with epidermal growth factor (EGF) to induce PGE2 synthesis and bone resorption, with or without bisphosphonates. The bisphosphonates either decreased, had no effect or increased PGE2 production, but all inhibited the release of calcium.
4. Finally, the bisphosphonates were given in vivo to mice before explantation of the calvaria. Some of the bisphosphonates decreased the production of PGE2, suggesting that these compounds may have such an effect in vivo. But again no relationship between the effect on PGE2 synthesis and bone resorption was found.
5. Thus, these experiments show the inhibitory effect of bisphosphonates on bone resorption is unlikely to be explained only by their effect on PGE2 synthesis.
Enhanced distal absorption of potassium by magnesium-deficient rats
Authors: Wong Norman L. M. , Sutton Roger A. L. , Mavichak Viroon , Quamme Gary A. , Dirks John H. 
Published: August 2015

1. The effect of acute potassium infusion on renal tubular reabsorption of potassium by magnesium-deficient and pair-fed control rats has been studied by the recollection micropuncture method.
2. During potassium chloride infusion, the amount of potassium remaining in the distal tubule is lower in magnesium-deficient than in pair-fed rats. This could be due to a reduction in potassium secretion or to an enhancement of potassium reabsorption.
3. The present study demonstrates enhanced renal potassium retention in the magnesium-deficient rat, and is in contrast to previous reports of renal potassium wasting in this circumstance.
The effect of indomethacin on the renal response to arginine vasopressin in man
Authors: Dixey J. J. , Williams T. D. M. , Lightman S. L. , Lant A. F. , Brewerton D. A. 
Published: August 2015

1. The renal response to graded intravenous infusions of arginine vasopressin (AVP) was investigated in a two part study in six volunteers. First, under maximal water diuresis, seven control incremental infusions of AVP were given from zero to 12 fmol min−1 kg−1. Second, the AVP infusions were repeated after pretreatment with indomethacin, 150 mg daily for 36 h.
2. After the AVP infusions, plasma AVP concentrations did not change significantly and remained within the physiological range; in contrast, urinary AVP excretion rate increased steadily. Indomethacin did not alter the plasma or urinary concentrations of AVP.
3. AVP caused a fall in urine flow rate from a state of maximal diuresis to one of maximal anti-diuresis. After indomethacin, fractional free water clearance was reduced by an average of 26% at the zero, 2 and 4 fmol min−1 kg−1 infusion rates of AVP.
4. A significant increase in fractional sodium clearance of approximately 50% occurred during the AVP infusions, which was abolished after pretreatment with indomethacin.
5. After indomethacin, urinary prostaglandin E2 (PGE2) excretion rate was reduced by an average of 40%) at the zero and 2 fmol min−1 kg−1 infusion rates of AVP. At higher AVP infusion rates, no significant inhibition of PGE2 was observed.
6. Urinary kallikrein excretion rate decreased steadily to one-third of its original value after AVP and this change remained unaltered by indomethacin.
7. The findings show that infusions of AVP, resulting in plasma concentrations in the physiological range, evoke a maximal antidiuretic response, which is accompanied by natriuresis. Significant inhibition of urinary prostaglandin excretion by indomethacin is accompanied by both enhancement of the antidiuretic effect of an abolition of the natriuretic response to AVP.
Calculation of the VD/VT ratio by the helium washout technique
Authors: Jordanoglou J. , Tatsis G. , Bissiouli Z. 
Published: August 2015

1. In four normal subjects and 51 patients with chronic bronchitis-emphysema, bronchial asthma and pulmonary fibrosis, the VD/VT ratio was measured by a helium washout technique (w VD/VT) and by the conventional Bohr's method using the arterial CO2 tension (VD/VT).
2. In 16 patients the w VD/VT ratio was compared with that calculated from Bohr's equation with the alveolar CO2 tension measured by the rebreathing technique (A VD/VT).
3. It was found that the values for the VD/VT ratio obtained by the helium washout technique were very close to those obtained by the conventional method using the Paco2 or P¯Aco2 values.
Assessment of the effect of nifedipine on myocardial ischaemia by using the ST segment/heart rate slope
Authors: Bishop N. , Hart G. , Elamin M. S. , Silverton N. P. , Boyle R. , Stoker J. B. , Smith D. R. , Mary D. A. S. G. , Linden R. J. 
Published: August 2015

1. Nifedipine is used in patients with stable angina of effort and any resulting change in symptoms is attributed to several effects of nifedipine. However, there have been indications in such patients that one effect of nifedipine could be an increase in the severity of myocardial ischaemia, and the present report involves a trial the results of which could explain this effect.
2. In the present trial, the effect of nifedipine on myocardial ischaemia was assessed by using the maximal ST/heart rate slope. This slope was used as an index of myocardial ischaemia because, in our hands in patients with angina, an increase or a decrease in the value of the slope respectively indicated an increase or a decrease in the severity of myocardial ischaemia as assessed by coronary arteriography.
3. The maximal ST/heart rate slope was obtained at least twice in each of 23 patients with stable angina, with and without nifedipine; two patients were examined twice and three other patients were examined after an increased dose. Nifedipine resulted in an increase in the slope in 24 of the 28 comparisons, no change in three and a decrease in one comparison; there was a statistically significant (P &lt; 0.005; n = 28; paired t-test) increase in the maximal ST/heart rate slope. A further increase in the slope was obtained by increasing the dose of nifedipine in two out of three patients.
4. The increase in the maximal ST/heart rate slope occurred in the absence of any effect of nifedipine on the initial level of the ST segment.
5. It is concluded that nifedipine therapy in the patients with stable angina caused increases in the maximal ST/heart rate slope, suggesting an increase in the severity of myocardial ischaemia.
Effect of peptide chain length on amino acid and nitrogen absorption from two lactalbumin hydrolysates in the normal human jejunum
Authors: Grimble G. K. , Keohane P. P. , Higgins B. E. , Kaminski M. V. , Silk D. B. A. 
Published: August 2015

1. A double lumen jejunal perfusion technique has been used in man to study the effect of peptide chain length on absorption of amino acid nitrogen from two partial enzymic hydrolysates of lactalbumin.
2. Copper-chelation chromatography showed that one lactalbumin hydrolysate (LH2) contained 98% peptides with a chain length &gt; 4, whilst the other (LH1) contained a more even spread of chain lengths with 55% &lt;4.
3. Absorption of total nitrogen and of 14 amino acid residues occurred to a significantly greater extent from the low molecular weight LH1 than from the higher molecular weight LH2.
4. The results suggest that the pattern of nitrogen and amino acid absorption from partial enzymic hydrolysates of whole protein is markedly influenced by peptide chain length and that brush border peptide hydrolysis has an important rate limiting effect on absorption rates.
Reappraisal of the ‘lectin hypothesis' in the aetiopathogenesis of coeliac disease
Authors: Colyer J. , Farthing M. J. G. , Kumar P. J. , Clark M. L. , Ohannesian A. D. , Waldron N. M. 
Published: August 2015

1. The agglutinating properties of a crude gluten digest, purified gliadin fractions and established plant lectins were investigated using mammalian erythrocytes, rat enterocytes and normal and coeliac human enterocytes as the target systems.
2. Gliadin preparations failed to cause agglutination of any of the cells tested, whereas established pure plant lectins were active cell agglutinins.
3. These studies indicate that gliadin peptides do not interact with intestinal cells in a polyvalent, lectin-like manner and as such cannot be regarded as true lectins.
4. Mucosal damage in coeliac disease is unlikely therefore to be related to lectin-like activity of gliadin.
Effect of simple short term dietary control on urine electrolyte excretion in normal men
Authors: McInnes Gordon T. , Flores Josue G. , Shelton John R. , Harrison Ian R. , Perkins Richard M. , Clarke Joan M. 
Published: August 2015

1. Normal diet and a simple short term prescribed diet were compared with respect to mean excretion of urine electrolytes and the variability in these responses in 12 healthy male subjects. Urine was collected from 7 to 15 h (overnight) and 15 to 25 h (daytime) after the start of dietary control.
2. Differences in mean responses were slight. For sodium and potassium excretion, however, there were tendencies for responses in subjects with high excretion on normal diet to decrease and for responses in those with low excretion on normal diet to increase towards the overall mean during the prescribed diet.
3. The prescribed diet reduced markedly the variability in electrolyte responses and for log transformed data reductions in variability were statistically significant in the daytime urine collections.
4. The results of this study have confirmed quantitatively the benefit of a short period of simple dietary control. The marked reduction in the variability of sodium and potassium excretion improves considerably the precision and sensitivity of studies of urine electrolyte composition.
Change in plasma immunoreactive atrial natriuretic peptide during sequential ultrafiltration and haemodialysis
Authors: Wilkins M. R. , Wood J. A. , Adu D. , Lote C. J. , Kendall M. J. , Michael J. 
Published: August 2015

1. Plasma immunoreactive human atrial natriuretic peptide (Ir-ANP) levels were measured in eight patients with chronic renal failure who were volume-expanded and during treatment by sequential ultrafiltration and haemodialysis. One patient was studied at two separate treatment sessions.
2. Plasma Ir-ANP levels were raised in all patients (mean ± SE 184 ± 44 pmol/l, n = 9) compared with healthy controls (11 ± 1.4 pmol/l), but showed considerable inter-patient variability.
3. Plasma Ir-ANP levels fell with fluid removal during ultrafiltration (123 ± 30 pmol/l, n = 9, P &lt; 0.02) and again as fluid was removed during haemodialysis (76 ± 20 pmol/l, n = 9, P &lt; 0.02).
4. Seven patients studied 48 h later, before their next dialysis treatment, had regained weight and showed a coincident rise in circulating plasma Ir-ANP (130 ± 33 pmol/l, n = 7).
5. Our data would support the hypothesis that the secretion of ANP is determined by volume or by a stimulus related to volume. However, it does not exclude the possibility that a factor other than extracellular fluid volume expansion contributes to the raised plasma Ir-ANP levels in chronic renal failure.
Kidney protection by pretreatment with free radical scavengers and allopurinol: Renal function at recirculation after warm ischaemia in rabbits
Authors: Hansson R. , Johansson S. , Jonsson O. , Pettersson S. , Scherstén T. , Waldenström J. 
Published: August 2015

1. Renal function and morphology were studied before and after 60 min of renal ischaemia and contralateral nephrectomy in five groups of rabbits. The animals were pretreated with superoxide dismutase, catalase, allopurinol or mannitol. One group was not pretreated and served as a control.
2. A moderate transient increase in serum creatinine concentration was observed in the control rabbits, while a significantly less pronounced increase was noted after pretreatment with superoxide dismutase, catalase and mannitol.
3. Pretreatment with allopurinol did not significantly reduce the postoperative increase in serum creatinine and sodium excretion, but the urine osmolality returned to normal more rapidly than in the control group.
4. The appearance under the light microscope of kidney tissue taken from surviving rabbits was found to be normal irrespective of pretreatment. Severe tubular necrosis was observed in the kidneys from rabbits that died during the observation period.