bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of the Natriuretic Activity in the Plasma of Hypervolaemic Rats
Authors: Veress A. T. , Milojevic S. , Sonnenberg H. 
Published: August 2015

1. Plasma from hypervolaemic rats was fractionated on a G-200 Sephadex column. In addition to three different protein peaks, a fourth non-protein fraction was obtained. Each of the four peaks was desalted, freeze-dried, reconstituted and injected into normal anaesthetized rats. Significant natriuretic responses resulted, from injection, of the middle protein peak and of the small-molecular-weight peak. It was concluded that a natriuretic humoral factor was present in the blood of hypervolaemic rats, and that this factor was of low molecular weight but normally occurred bound to plasma protein.
2. The renal response to injection of non-protein fraction, obtained from either hypervolaemic donors or from iso- or hypo-volaemic donors, was compared in two groups of bioassay rats to test whether the natriuretic factor was present only in plasma of the blood-volume-expanded animals. Both types of reconstituted fraction caused diuresis, natriuresis and kaliuresis in bioassay animals. Only the natriuretic response was statistically greater when the fraction obtained from hypervolaemic plasma was used. In addition to non-specific increase in fluid and ion excretion, possibly due to the extraction and/or methodological procedures, these results demonstrate that blood-volume expansion releases a humoral natriuretic factor into plasma. Since there were no increases in filtration rate, the factor specifically inhibited tubular sodium re-absorption.
3. To determine the maximum possible effect of the non-protein factor, the dose given to bioassay rats was tripled. There was no further increase in sodium excretion, indicating that the effect was quantitatively limited and suggesting that the physiological importance of natriuretic hormone lies in long-term regulation of body-fluid balance.
Forearm Glucose Uptake in Cirrhosis and Its Relationship to Glucose Tolerance
Authors: Leatherdale B. A. , Chase R. A. , Rogers J. , Alberti K. G. M. M. , Davies P. , Record C. O. 
Published: August 2015

1. Oral glucose-tolerance tests (100 g) were carried out in six patients with stable well-compensated cryptogenic cirrhosis and in 12 control subjects.
2. In confirmation of previous studies, patients with cirrhosis had high post-glucose serum insulin levels and were glucose intolerant (mean incremental glucose area 954 ± 186 compared with 482 ± 35 mmol 3 h−11−1 in controls; P&lt;0.05)
3. Forearm arteriovenous differences of glucose and forearm blood flows were measured to estimate the proportion of the glucose load metabolized in peripheral tissues. Values in cirrhotic patients and control subjects (5614 ± 1630 compared with 5344 ± 672 μmol of glucose min−11−1 of forearm in 3 h) were similar despite higher glucose levels and sustained high insulin levels in the cirrhotic patients.
4. Peak lactate concentrations after glucose were of similar magnitude in the two groups (0.66 ± 0.12 compared with 0.62 ± 0.75 mmol/l) but in the patients with cirrhosis the peak occurred later and was more sustained.
5. The glucose intolerance of cirrhosis is primarily due to impaired hepatic retention of the glucose load. Insulin resistance in peripheral tissues-5-also be important since the higher insulin concentrations found in cirrhotic patients failed to enhance peripheral glucose uptake.
Importance of the Cyclic AMP Concentration for the Rate of Lipolysis in Human Adipose Tissue
Authors: Arner P. , Östman J. 
Published: August 2015

1. The activation of lipolysis on incubation of human subcutaneous adipose tissue was examined in terms of the relationship between the release of glycerol and the concentration of tissue cyclic AMP.
2. A strong positive correlation was obtained between the maximum concentration of cyclic AMP and the rate of glycerol release in the presence of noradrenaline (r = 0.9), whereas, in the basal state, these two parameters were only weakly correlated (r = 0.45).
3. It appears that the noradrenaline-induced rate of lipolysis depends upon the maximal concentration of cyclic AMP that is present in human adipose tissue.
Myocardial Electrical Instability after Abrupt Withdrawal of Long-Term Administration of Propranolol to Guinea Pigs
Authors: Dennis S. C. , Manning A. S. , Hearse D. J. , Coltart D. J. 
Published: August 2015

1. Abrupt termination of chronic propranolol therapy has been suggested to cause a ‘rebound’ phenomenon. To investigate this possibility guinea pigs were given propranolol orally for 21 days.
2. At various times over a 10 day period after the last dose hearts were removed and subjected to aerobic perfusion, ischaemia and reperfusion. Rhythm disturbances were measured and compared with corresponding values in control hearts from the control untreated animals.
3. Three to 6 days after termination of drug administration a pronounced increase in myocardial electrical instability was observed. During pre-ischaemic aerobic perfusion the incidence of arrhythmias was increased and during reperfusion the incidence of ventricular fibrillation rose dramatically.
Renin Precursor and Its Activation Mechanism in Hog Kidney
Authors: Murakami Kazuo , Takahashi Saori , Hirose Shigehisa , Takii Yukio , Inagami Tadashi 
Published: August 2015

1. A completely inactive renin was isolated from hog kidney extract by affinity chromatography on pepstatin-aminohexyl-Sepharose and on an Affi-Gel Blue column.
2. This inactive renin had a molecular weight of 43 000 ± 1500 as determined by gel filtration on Ultrogel AcA 44. Upon activation with trypsin, its molecular weight fell to 41 000 ± 1400.
3. The inactive renin lacked the ability to bind renin-binding substance whereas trypsin-activated renin was able to bind the renin-binding protein and to form high-molecular-weight renin.
4. Chymotrypsin as well as trypsin could activate the inactive renin although less effectively.
5. The active renins generated from the inactive renin by the action of different proteolytic enzymes differed in their net charge, reflecting the specificities of the proteases used; the isoelectric points of the native, the trypsin-activated and the chymotrypsin-activated forms of renin occurred at pH 5.3, 5.1 and 4.8 respectively.
Elevation of Plasma Neurotensin in the Dumping Syndrome
Authors: Blackburn A. M. , Christofides N. D. , Ghatei M. A. , Sarson D. L. , Ebeid F. H. , Ralphs D. N. L. , Bloom S. R. 
Published: August 2015

1. The pathophysiology of the dumping syndrome is poorly understood. Plasma levels of four small intestinal hormones have been measured after an oral glucose provocation test in 19 patients with dumping symptoms and in matched controls.
2. Plasma levels of neurotensin, a newly discovered highly potent, hypotensive ileal peptide, were significantly increased in symptomatic patients compared with those of controls [20 min rise of 43 ± 6.0 (mean ± sem) pmol/l in 19 symptomatic patients, 8.0 ± 5.5 pmol/l in 20 postoperative symptom-free patients, and 4.1 ± 3.5 pmol/l in 20 pre-operative patients with duodenal ulcer, P &lt; 0.01].
3. The rise in enteroglucagon was greater than normal but of similar magnitude to that seen in several other gastrointestinal conditions not associated with dumping symptoms.
4. The release of both gastric inhibitory peptide and motilin did not differ significantly from that of controls.
An Inactive, Prorenin-like Substance in Human Kidney and Plasma
Authors: Atlas S. A. , Laragh J. H. , Sealey Jean E. , Hesson T. E. 
Published: August 2015

1. Plasma prorenin (inactive renin), which accounts for about 70% of the total renin in human plasma, was almost completely separated from active renin by affinity chromatography on Cibacron blue F3G-A-agarose. The slight residual renin activity present in the prorenin peak can be removed on concanavalin A-Sepharose, demonstrating that prorenin is completely inactive.
2. The renin activity of both human renal cortical extract and renal perfusate increased after incubation with trypsin. This trypsin-activable renin accounted for 15 and 40% of the total renin in extract and perfusate respectively.
3. Trypsin-activable renin from both renal extract and renal perfusate was, like plasma prorenin, almost completely separated from active renin on Cibacron blue F3G-A-agarose. After additional chromatographic steps, the trypsin-activable renin from renal cortical extract was found to be completely inactive.
4. We conclude that human kidney contains, and is able to release, a trypsin-activable renin that resembles plasma prorenin. It may differ from many of the 60 000 molecular-weight forms of renin previously identified in renal extracts, since these possess considerable intrinsic renin activity and probably represent a complex of renin with a binding protein.
Baroreflex Sensitivity Changes during the Development of Goldblatt Two-Kidney One-Clip Hypertension in Rats
Authors: Jones J. V. , Floras J. S. 
Published: August 2015

1. The time course of changes in baroreceptor reflex sensitivity during the development of renovascular hypertension was studied in male Wistar rats in which the left renal arteries were constricted by silver wire clips of 0.18 mm internal diameter.
2. Groups of animals were studied at 3, 7, 14 and 25 days after induction of renovascular hypertension. Rats of comparable ages were included as controls. There was a significant decrease in mean baroreflex sensitivity from 0.950 ± 0.157 ms/mmHg (n = 8) in the normal control group to 0.537 ± 0.105 ms/mmHg (n = 8) in the 3 day hypertensive group (P &lt; 0.05). Baroreflex sensitivity in the 3 day hypertensive rats was independent of the level of arterial pressure achieved in individual animals.
3. These changes in baroreflex sensitivity at 3 days precede the development of left ventricular hypertrophy and, as previously shown in this model, also precede structural vascular adaptation and resetting of the carotid sinus baroreceptor threshold.
4. A further loss of baroreflex sensitivity, which may be structurally based, occurred later. Baroreflex sensitivity in the 14 day hypertensive rats fell to 0.182 ± 0.039 ms/mmHg (n = 8) compared with the 3 day hypertensive rats (P &lt; 0.01).
A Comparison of Multiple Forms of Renin in Rat Renal Perfusate with those in Renal Extract
Authors: Nakane Haruyuki , Nakane Yoko , Misumi Jiro , Saruta Takao , Corvol Pierre , Menard Joël 
Published: August 2015

1. Physicochemical properties of renin secreted by isolated perfused rat kidney were examined and the results compared with those obtained for the renin in renal extract.
2. In renal extract, two high-molecular-weight reruns (molecular weight 65 000 and 55 000) and one low-molecular-weight renin (molecular weight 39 000) were found. Their relative proportion varied depending on extraction conditions. By acidification, high-molecular-weight renins were converted into low-molecular-weight renin without marked changes in activity.
3. In renal perfusate only low-molecular-weight renin was found after renin stimulation by isoprenaline or anoxia. Inactive renin was not found.
4. Renin in renal extract and perfusate samples were both found to consist of at least four isoenzymes having different isoelectric points (pI). The pI patterns were identical in renal extract and perfusate samples: pI 5.7 (60-70%), 5.5 (15-25%), 5.3 (5-10%) and 5.0-5.2 (2-5%).
5. These results indicate that the native renin secreted by rat kidney consists entirely of the low-molecular-weight and active form comprising multiple isoenzymes with a stable pI pattern.
Immunochemical Differences between Angiotensin I-Forming Enzymes in Man
Authors: Menard J. , Galen F.-X. , Devaux C. , Kopp N. , Auzan Colette , Corvol P. 
Published: August 2015

1. Human plasma, amniotic fluid and acidified amniotic fluid were incubated at pH 5.5 with the same concentrations of human plasma renin substrate and rat plasma renin substrate. They produced three to eight times more angiotensin I with human than with rat renin substrate. By contrast, human brain extracts generated 20 times more angiotensin I when incubated with rat plasma renin substrate than with human plasma renin substrate.
2. Serial dilutions of anti-(human renin) antibody inhibited, in a dose-dependent manner, the production of angiotension I when plasma, amniotic fluid and brain extracts were incubated with human plasma renin substrate. They also inhibited the production of angiotensin I when plasma and amniotic fluid were incubated with rat plasma renin substrate. They were ineffective on the angiotensin I generation by human brain extracts acting on rat plasma renin substrate.
3. Affinity chromatography on an haemoglobin-Sepharose gel separated the fraction of brain extract acting on human renin substrate and inhibited by anti-(human renin) antiserum; this was not retained on the gel at pH 3.3. Part of the angiotensin I-forming activity detected by rat renin substrate hydrolysis was not retained on the gel and part was eluted at pH 8.5. These angiotensin I-forming activities did not hydrolyse human renin substrate, and were not neutralized by anti-(human renin) antibody.
4. These results demonstrate that a renin, immunochemically identical with renal, plasma and amniotic fluid renin, is present in the human brain. Other angiotensin I-forming activity, acting on an heterologous substrate at a more acidic pH, is also present in human brain.
Subcellular Fractionation Studies of Human Rectal Mucosa; Localization of the Mucosal Peptide Hormones
Authors: Dawson J. , Bryant M. G. , Bloom S. R. , Peters T. J. 
Published: August 2015

1. Analytical subcellular fractionation techniques have been applied to endoscopic human rectal biopsies to study the localization of enteroglucagon, somatostatin, vasoactive intestinal peptide and the properties of the principal subcellular organelles.
2. The peptide hormones, detected by radioimmunoassay, showed particulate localizations with single peaks in the density gradients for enteroglucagon (modal density 1.25) and somatostatin (modal density 1.23). Vasoactive intestinal peptide showed a less discrete localization but demonstrated a major peak (modal density, 1.17) with a small subsidiary peak (modal density 1.24).
3. The following organelles, characterized by their marker enzymes, were located in the density gradients; plasma membrane (5′-nucleotidase), mitochondria (malate dehydrogenase), peroxisomes (catalase), lysosomes (β-N-acetyl-d-glucosaminidase), endoplasmic reticulum (neutral α-d-glucosidase) and cytosol (lactate dehydrogenase).
4. This technique can be used to investigate disease of the human rectum at a subcellular level.
Fat Metabolism in Heavy Exercise
Authors: Jones N. L. , Heigenhauser G. J. F. , Kuksis A. , Matsos C. G. , Sutton J. R. , Toews C. J. 
Published: August 2015

1. To investigate differences between the metabolic effects of light and heavy exercise, five healthy males (mean maximal oxygen intake 3.92 litres/min) exercised for 40 min at 36% maximum power (light work) and 70% maximum power (heavy work) on separate days, after an overnight fast.
2. A steady state was achieved in both studies between 20 and 40 min in: oxygen intake (1.42 and 2.64 litres/min respectively); respiratory exchange ratio (0.89 and 1.01); plasma lactate concentration (1.78 and 9.94 mmol/l).
3. Plasma palmitate turnover rate (14C) was unchanged from resting values in light work but was decreased by 40% (from 104 ± 16 to 63 ± 8 μmol/min) in heavy work. Heavy work was associated with falls in the plasma concentrations of all free fatty acids measured: palmitic acid (C16:0), oleic acid (C18:1), stearic acid (C18:0), linoleic acid (C18:2) and palmitoleic acid (C16:1).
4. In contrast to the fall in palmitate turnover the increase in plasma glycerol was greater in heavy exercise (0.054–0.229 mmol/l) than in light exercise (0.053–0.094 mmol/l), suggesting that lipolysis was occurring which did not lead to influx of free fatty acids into plasma.
5. In light exercise fat metabolism may be controlled to favour adipose tissue lipolysis and extraction of free fatty acids by muscle from the circulation, whereas in heavy exercise adipose tissue lipolysis is inhibited and hydrolysis of muscle triglycerides may play a more important part.
6. The finding of a high respiratory exchange ratio may not exclude the use of fat as a major fuel source in exercise associated with lactate production.
Renin in Rat and Mouse Brain: Immunohistochemical Identification and Localization
Authors: Inagami T. , Celio M. R. , Clemens D. L. , Lau D. , Takii Y. , Kasselberg A. G. , Hirose S. 
Published: August 2015

1. Localization of renin in rat and mouse brain was determined by immunohistochemical methods with specific anti-renin antibodies.
2. Renin-containing neuronal cells were found in the medulla oblongata, cerebellar nuclei and hypothalamus. Purkinje cells contained renin.
3. Glia-like cells contained renin. Some of them are closely associated with vascular walls and these vascular walls were renin positive.
4. The pineal gland, adenohypophysis and choroid plexus contained renin.
5. The extensive distribution of renin suggests functions other than those which have been associated with the hypothalamus.
Subcellular Localization of Serotonin and Motilin in the Human Jejunum
Authors: Dawson J. , Bryant M. G. , Cox A. G. , Christofides N. D. , Bloom S. R. , Peters T. J. 
Published: August 2015

1. Analytical subcellular fractionation techniques have been applied to human jejunal homogenates to study the localization of serotonin and motilin.
2. Serotonin, detected by a fluorimetric assay, showed two distinct particulate distributions in the density gradients with modal densities of 1.14 and 1.20. Motilin, whether detected by N-terminal or C-terminal specific antibodies showed similar density distributions with a modal density of 1.20, coinciding with the denser peak of serotonin.
3. These results lend support to the histochemical suggestions that motilin is located in a serotonin-containing granule.
Immunocytochemical Localization of Angiotensin II and Vasopressin in Rat Hypothalamus: Evidence for Production in the Same Neuron
Authors: Kilcoyne M. M. , Hoffman D. L. , Zimmerman E. A. 
Published: August 2015

1. By immunoperoxidase technique, immunoreactive angiotensin II (ANG II) was located in the cell bodies of many magnocellular neurons in the supraoptic and paraventricular nuclei of the hypothalamus and their pathways to median eminence and posterior pituitary gland in the rat.
2. Like vasopressin and its neurophysin, but not oxytocin, ANG II was also found in parvocellular neurons in the suprachiasmatic nucleus.
3. Analysis of these peptides in the same magnocellular neurons reveals that ANG II is localized primarily in vasopressin cells.
4. Like vasopressin and its precursor, ANG II is deficient in homozygous Brattleboro rats with diabetes insipidus.
5. In adrenalectomized rats increases in vasopressin and its neurophysin in median eminence are associated with increases in ANG II.
6. The data suggest that the ANG II demonstrated shares antigenic determinants with the vasopressin precursor, or is regulated in a similar way to vasopressin in the same neurons.
Hypotensive Effects of Captopril, Saralasin and Bromocriptine in Spontaneously Hypertensive Rats
Authors: Hutchinson J. S. , Doyle A. E. 
Published: August 2015

1. Neurosecretion of peptides from superfused neurohypophyses in vitro was inhibited by dopamine.
2. This inhibition was dose-dependent.
3. Intravenous injection of the dopamine agonist, bromocriptine, lowered blood pressure in spontaneously hypertensive rats within 15 min.
4. Saralasin or captopril also lowered blood pressure of spontaneously hypertensive rats, but progressively over a period of 3 h.
5. The results suggest that dopamine and angiotensin have opposite effects on the neurosecretion of vasopressin.
6. Vasopressin appears to be involved in maintenance of blood pressure in the spontaneously hypertensive rat but is apparently not the only factor.
Dopaminergic Control of Aldosterone Secretion is Independent of the Renin—Angiotensin System in Rats
Authors: Sowers J. R. , Tuck M. L. , Barrett J. , Sambhi M. P. , Golub M. S. 
Published: August 2015

1. In rats, intra-arterial metoclopramide, a dopamine antagonist, resulted in an elevation of plasma aldosterone at 5 min and plasma renin activity at 10 min and peak aldosterone and renin responses at 10 and 30 min respectively.
2. Pre-administration of l-dopa blunted and delayed aldosterone and renin responses to metoclopramide, indicating that metoclopramide-induced plasma aldosterone and plasma renin activity increments are mediated by a direct effect of blockade of dopamine receptors rather than other effects of this drug.
3. Pre-administration of angiotensin converting enzyme inhibitor, captopril (SQ 14 225) and the angiotensin II antagonist, saralasin, as well as bilateral nephrectomy did not significantly affect the aldosterone response to metoclopramide, Thus dopaminergic modulation of aldosterone secretion occurs independently of alterations in the renin-angiotensin system.
4. Modulating effects of dopamine on plasma aldosterone are probably mediated by direct effects as well as by interaction with other factors influencing aldosterone secretion at the adrenal zona glomerulosa.
Influence of Sodium on Experimental Renovascular Hypertension in Rats
Authors: Taquini C. M. , Gallo A. , Basso N. , Taquini A. C. 
Published: August 2015

1. Rats on normal sodium diet (group 1) and on chronically maintained low sodium diet (group 2) were studied during a control period, after clipping the renal artery (two-kidney, one-clip hypertension) and after nephrectomy (one-kidney, one-clip hypertension).
2. The low sodium diet neither prevented the development nor changed the severity of two-kidney, one-clip hypertension, and the latter was not accompanied by an increase in plasma renin activity.
3. After nephrectomy arterial pressure further increased and plasma renin activity decreased in group 1, and both remained unchanged in group 2.
4. Blood volume was the same in both groups 10 days before and 10 days after nephrectomy.
5. Sodium does not seem to be ‘necessary’ in the two-kidney, one-clip hypertension although it may play an enhancing role in the one-kidney model.
An Inherited Sodium Ion-Potassium Ion Cotransport Defect in Essential Hypertension
Authors: Garay R. P. , Dagher G. , Meyer P. 
Published: August 2015

1. In erythrocytes, the extrusion of a cell sodium load is accomplished by the ouabain-sensitive sodium-potassium pump and by the frusemide-sensitive sodium-potassium cotransport, which operate against the passive sodium permeability. All these three components of the cell sodium balance were studied in essential hypertension (410 subjects were investigated).
2. An abnormally low rate of net sodium extrusion by the sodium-potassium cotransport system was observed in essential hypertensive patients and in a high proportion of their young normotensive offspring. A normal cotransport system found in secondary hypertensive subjects devoid of familial history of hypertension confirmed that the abnormal cotransport system is not the consequence of high blood pressure per se.
3. A 20–40% increase in the rate of net sodium extrusion by the sodium-potassium pump seems to compensate for the abnormal cotransport in erythrocytes from some young normotensive subjects born of essential hypertensive parents and from some benign essential hypertensive subjects.
4. No difference could be detected between the passive sodium permeability of erythrocytes from hypertensive subjects and in those from normotensive controls.
5. In conclusion, essential hypertension seems to be associated with an inherited defect in the sodium-potassium cotransport system. We propose therefore the laboratory study of this system for: (i) the distinction between essential and secondary hypertension and (ii) the preventive investigation of young normotensive subjects in hypertensive families.