bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Interpretation of the Intravenous Glucose Tolerance Test in the Light of Recent Findings on the Kinetics of Glucose and Insulin in Man
Authors: Cunningham V. J. , Heath D. F. 
Published: August 2015

1. A theoretical investigation of the intravenous glucose tolerance test has been carried out based on recent findings on the kinetics in man of insulin production, distribution, disposal and action, and of glucose turnover and distribution.
2. A good fit to published data on four groups of subjects required a scheme that includes two extravascular glucose spaces and separate venous, arterial and capillary volumes. The fit to the data was little affected by variations within the physiological range of venous and arterial volumes, cardiac output, glycosuria and the properties of the less-accessible glucose pool.
3. The only variables needed to account for the differences between the groups were kinsulin (a measure of the mean sensitivity of insulin-dependent tissues to insulin action) and the readily accessible glucose space.
4. Three published schemes for insulin kinetics were used. They were all consistent with the data and gave very similar relative values of kinsulin in the four groups.
5. It is shown that a rigorous interpretation of the test requires a knowledge of the hepatic response to the glucose load during the test. These effects are not well characterized in pathological states, e.g. diabetes and injury. Consequently conclusions about insulin resistance in these states drawn only from the test are doubtful.
Relationships between Cardiac Output, Heart Rate and Blood Volume in Essential Hypertension
Authors: Chau N. P. , Safar M. E. , Weiss Y. A. , London G. M. , Simon A. Ch. , Milliez P. L. 
Published: August 2015

1. Cardiac haemodynamics were determined in 196 male untreated subjects, comprising 98 normotensive individuals and 98 hypertensive patients of the same age.
2. In order to study the haemodynamic change in hypertension, a new methodology was proposed. The whole population was classified by increasing diastolic pressures and divided into overlapping subgroups. From subgroup to subgroup, mean values of different haemodynamic variables were plotted against mean values of diastolic pressures. Three phases could be observed in the changes of these variables. In the first phase (for mean diastolic pressures under about 80 mmHg), the rise in pressure was associated with a decrease in blood volume and with an increase both in cardiac output and heart rate. In the second phase (for mean diastolic pressures between 80 mmHg and 95 mmHg approximately), heart rate, cardiac output and blood volume remained at the same values. In the third phase (for mean diastolic pressure above approximately 95 mmHg), heart rate remained elevated while the rise in pressure was associated with a decrease both in cardiac output and blood volume.
2. In the same subgroups, the correlations between cardiac output and heart rate and between cardiac output and blood volume were studied. The correlation between cardiac output and heart rate was significant only in normotensive ranges while the correlation between cardiac output and blood volume was significant only in hypertensive ranges.
3. Classical statistical tests, performed in distinct subgroups, confirmed the above observations on the changes of mean values and correlations.
5. The study provided evidence that cardiac output was predominantly controlled by neural mechanisms within the normotensive range and by volume mechanisms within the hypertensive range.
The Degradation of Human Glomerular Basement Membrane with Purified Lysosomal Proteinases: Evidence for the Pathogenic Role of the Polymorphonuclear Leucocyte in Glomerulonephritis
Authors: Davies M. , Barrett A. J. , Travis J. , Sanders E. , Coles G. A. 
Published: August 2015

1. Human polymorphonuclear leucocyte elastase and cathepsin G were incubated with preparations of isolated human glomerular basement membrane at neutral pH and 37°C.
2. The ability of these enzymes to degrade glomerular basement membrane was followed by the release of hydroxyproline. Both proteinases released considerable amounts of hydroxyproline.
3. By using Sephadex G-100 it was shown that the solubilized basement membrane fragments appeared as a single peak and had a molecular weight of over 100 000. These proteins after reduction were analysed by sodium dodecyl sulphate-gel electrophoresis to examine their subunit pattern and determine their molecular size.
4. The released basement membrane proteins gave at least four precipitin lines with a rabbit anti-(glomerular basement membrane) antiserum.
5. These results support the concept that polymorphonuclear leucocyte neutral proteinases play an important role in the pathogenesis of glomerulonephritis.
6. At acid pH values cathepsin B also released hydroxyproline from human glomerular basement membrane but the lysosomal carboxyl proteinase, cathepsin D, had no action.
Family Studies on the Activity of Uroporphyrinogen I Synthase in Diagnosis of Acute Intermittent Porphyria
Authors: Astrup E. G. 
Published: August 2015

1. Ten subjects with acute intermittent porphyria from three different families, and 92 relatives, were investigated for their erythrocyte uroporphyrinogen I synthase (EC 4.3.1.8) activities by the spectrofluorimetric method described and for their urinary concentrations of δ-aminolaevulinic acid and porphobilinogen.
2. The mean uroporphyrinogen I synthase activity in 41 healthy women and 41 healthy men showed a significant (P < 0·001) sex difference.
3. A reduction of about 32% of the enzyme activity was observed in the porphyric subjects as compared with values in healthy normal subjects and the values from the porphyric subjects overlapped those of the reference subjects.
4. With the values from the normal subjects in each family used as reference, however, the enzyme activity in normal subjects was twice that in affected subjects. Thus by using an internal family reference uroporphyrinogen I synthase values became more reliable in disclosing latent cases of the disorder. Furthermore, these measurements were shown to have a stronger discriminative power than urinary δ-aminolaevulinic acid and porphobilinogen determinations.
Control of Breathing in Patients with Chronic Obstructive Lung Disease
Authors: Šorli J. , Grassino A. , Lorange G. , Milic-Emili J. 
Published: August 2015

1. Using the mouth occlusion pressure technique, we have studied the control of breathing in seven hypercapnic and eight non-hypercapnic patients with chronic obstructive lung disease.
2. When breathing room air, pulmonary ventilation, mean inspiratory flow and P0·1 (mouth occlusion pressure developed 0·1 s after the onset of occluded inspiration at functional residual capacity) were not significantly different between the two groups of patients. Tidal volume, however, was significantly lower in the hypercapnic than in the non-hypercapnic patients, as a result of a significantly lower duration of inspiration.
3. The lower tidal volume in the hypercapnic patients leads to decreased alveolar ventilation, and appears to be the main cause of retention of carbon dioxide.
A Radioimmunoassay for 1,25-Dihydroxycholecalciferol
Authors: Clemens T. L. , Hendy G. N. , Graham R. F. , Baggiolini E. G. , Uskokovic M. R. , O'Riordan J. L. H. 
Published: August 2015

1. 1α,25-Dihydroxy-25-hemisuccinate cholecalciferol has been synthesized and conjugated to bovine serum albumin.
2. This conjugate is immunogenic; when injected into rabbits antibodies of high affinity for 1α,25-dihydroxycholecalciferol were obtained.
3. Vitamin D metabolites lacking the 1α-hydroxy group were of lower cross-reactivity with the antibodies.
4. By using these antibodies and 1α,25-[23,24-3H]dihydroxycholecalciferol as tracer a sensitive radioimmunoassay has been developed capable of detecting 20 pg of 1α,25-dihydroxycholecalciferol.
The Effect of Acute Extracellular Volume Expansion on Sodium Chloride Reabsorption in the Diluting Segment in Man
Authors: Ish-Shalom N. , Rapoport J. , Chaimovitz C. , Better O. S. 
Published: August 2015

1. The effect of extracellular volume expansion (ECVE) during water diuresis, and of water diuresis alone, on the formation of free water in man was compared.
2. ECVE reduced free water formation at any given rate of distal delivery compared with water diuresis. Thus, ECVE depresses distal sodium chloride reabsorption.
3. This attenuation of free water formation occurred both when urine flow (V/100 ml glomerular filtration rate) and distal chloride delivery [(Cwater + CCl)/100 ml glomerular filtration rate] were used as the terms for distal delivery.
4. We suggest that the distal depression of sodium chloride reabsorption after ECVE is probably due to a direct inhibition of distal sodium chloride transport mechanisms, and not to the flooding of the diluting site by the poorly reabsorbable bicarbonate ion.
Structure—Activity Relations of the Fibrinolytic Response to Vasopressins in Man
Authors: Cash J. D. , Gader A. M. A. , Mulder J. L. , Cort J. H. 
Published: August 2015

1. The systemic plasminogen activator response has been examined after intravenous infusion of the following peptides related to neurohypophyseal hormones in approximately equimolar dosages into informed, consenting human volunteer subjects: (a) the natural nonapeptides: lysine- and arginine-vasopressin, oxytocin and arginine-vasotocin, (b) the N- and C-terminal tripeptide fragments of vasopressin and (c) four vasopressin analogues without pressor activity, altered at the N-terminus, the disulphide bridge and/or sequence position 8 in the C-terminal tripeptide. In addition, angiotensin II and adrenaline were infused.
2. It was observed that some of the cyclic nonapeptides resulted in high and prolonged increases in amounts of plasminogen activator in venous blood, in the following order, both for amplitude and duration: 1-desamino-6-monocarba-[8-d-arginine]-vasopressin > 1-desamino-[8-d-arginine]-vasopressin ≫ arginine-vasopressin = lysine-vasopressin > Nα-glycyl-glycyl-glycyl-lysine-vasopressin.
3. No plasminogen activator responses followed infusions of vasopressin tripeptide fragments, oxytocin, angiotension II, 1-desamino-[8-N-MeArg]-vasopressin or 9-desglycineamide-lysine-vasopressin octapeptide.
4. Mole for mole, the four most active substances were approximately two orders of ten more potent than adrenaline by amplitude comparison alone.
5. Intra-arterial adrenaline, in one-tenth the systemic dose, stimulated a release of plasminogen activator from the infused local vascular bed only, This did not occur with equivalent doses of arginine-vasopressin and 1-desamino-[8-d-arginine]-vasopressin.
6. It is concluded that plasminogen activator release arising from catecholamine-responding and vasopressin-responding receptors are both molecule-specific and different in anatomical location. The molecular structural requirements for triggering the latter hypothetical receptor type and potential clinical applications are discussed.
Changes in Absorptive and Peptide Hydrolase Activities in Rat Small Intestine after Administration of 5-Fluorouracil
Authors: Gardner M. L. G. , Samson R. R. , Heading R. C. 
Published: August 2015

1. Glucose absorption, water absorption and dipeptide hydrolase activities have been determined in isolated rat small intestine at 1, 3, 5 and 21 days after a single intraperitoneal injection of 5-fluorouracil.
2. Absorption rates and enzyme activities were elevated 1 day after treatment, but were reduced to 40% of control values at 3 and 5 days. Changes were seen regardless of whether absorption was expressed per unit length or per unit dry weight of intestine.
3. There were highly significant positive correlations between glucose or water absorption rates and peptidase activities, especially in proximal jejunum. The most significant correlation was observed between water absorption rate and jejunal l-Leu-Gly hydrolase activity.
4. Malabsorption may account for some of the gastrointestinal side effects associated with treatment with 5-fluorouracil. Enzyme measurements may be useful as an index of intestinal function.
Effect of Oophorectomy and Calcium Deprivation on Bone Mass in the Rat
Authors: Hodgkinson A. , Aaron Jean E. , Horsman A. , McLachlan M. S. F. , Nordin B. E. C. 
Published: August 2015

1. The effects of a low calcium diet and of oophorectomy, separately and together, on cortical and trabecular bone mass, have been examined in mature female rats.
2. Calcium deprivation caused a significant decrease of weight, cortical cross-sectional area and ratio of cortical to total area in the femur, it significantly reduced the volume of trabecular bone and increased the percentage of osteoid surface in the tail vertebrae, and in addition increased the urinary excretion of phosphate and, initially, of hydroxyproline.
3. Oophorectomy caused similar though smaller changes in trabecular bone and urine, whereas the effects of oophorectomy on cortical bone were greater on a low calcium intake than on a normal intake.
4. The ash weight of the femora, expressed as a percentage of the total dry weight, was unaffected by calcium deprivation or oophorectomy alone but was significantly reduced when the two occurred together.
5. The percentage of resorption surfaces in the vertebrae tended to increase on the low calcium diet and after oophorectomy on the normal diet but decreased after oophorectomy on a low calcium diet.
6. It is concluded that oophorectomy and calcium deficiency each reduce bone mass in the adult rat but the greatest effect is seen when they are combined.
Effects of Acute Acid–Base Alterations on Glutamine Metabolism and Renal Ammoniagenesis in the Dog
Authors: Fine A. , Bennett F. I. , Alleyne G. A. O. 
Published: August 2015

1. The effects of acute acid—base alterations on renal ammonia production and glutamine metabolism were studied in anaesthetized dogs.
2. Plasma glutamine rose with acidosis and also when both Pco2 and plasma HCO−3 were raised isohydrically.
3. Blood urea fell when acidosis was induced with hydrochloric acid.
4. The renal production of ammonia per ml of renal blood flow was increased in acidosis, but this was independent of the amount of glutamine delivered to the kidney.
5. The results indicate that acute acidosis affects production of urea and glutamine and increases the capacity of the renal cells to extract glutamine from blood.
Purine Biosynthesis De Novo by Lymphocytes in Gout
Authors: Kamoun P. , Chanard J. , Brami M. , Funck-Brentano J. L. 
Published: August 2015

1. A method of measurement in vitro of purine biosynthesis de novo in human circulating blood lymphocytes is proposed. The rate of early reactions of purine biosynthesis de novo was determined by the incorporation of [14C]formate into N-formyl glycinamide ribonucleotide when the subsequent reactions of the metabolic pathway were completely inhibited by the antibiotic azaserine.
2. Synthesis of 14C-labelled N-formyl glycinamide ribonucleotide by lymphocytes was measured in healthy control subjects and patients with primary gout or hyperuricaemia secondary to renal failure, with or without allopurinol therapy.
3. The average synthesis was higher in gouty patients without therapy than in control subjects, but the values obtained overlap the normal range. In secondary hyperuricaemia the synthesis was at same value as in control subjects.
4. These results are in agreement with the inconstant acceleration of purine biosynthesis de novo in gouty patients as seen by others with measurement of [14C]glycine incorporation into urinary uric acid.
Effect of Administration of Sar1-Ala8-Angiotensin II during the Development and Maintenance of Renal Hypertension in the Rat
Authors: Fernandes M. , Fiorentini R. , Onesti G. , Bellini G. , Gould A. B. , Hessan H. , Kim K. E. , Swartz C. 
Published: August 2015

1. Sar1-Ala8-Angiotensin II (an angiotensin antagonist) was infused in rats during the development and maintenance of renal hypertension produced by aortic ligation between renal arteries.
2. In the early phase (5 and 12 days after ligation), infusion of the antagonist markedly decreased blood pressure although it did not reach normal pressures. Later (day 40) only a modest decrease in blood pressure was noted.
3. Removal of the small left kidney always decreased the blood pressure to normal pressures.
4. It is concluded that the renin—angiotensin system is the major pressor component in the initiation of this hypertension. Later, other factors of renal origin assume a pressor function.
Renal Function in Chronic Obstructive Jaundice: A Micropuncture Study in Rats
Authors: Allison Marjorie E. M. , Moss N. G. , Fraser Mary M. , Dobbie J. W. , Ryan C. J. , Kennedy A. C. , Blumgart L. H. 
Published: August 2015

1. We have studied kidney structure and function in female Sprague—Dawley rats with chronic obstructive jaundice after bile-duct ligation and section and in age-matched sham-operated control animals.
2. High bile-duct ligation and section resulted in immediate hyperbilirubinaemia and progressive hepatomegaly with histological evidence of bile-duct proliferation and periportal inflammation and fibrosis.
3. Only 20% of the jaundiced animals developed ascites, but 42% became hypotensive and died during preparation for micropuncture.
4. In the surviving rats there was no significant change in blood pressure, whole-kidney glomerular filtration rate, single-nephron glomerular filtration rate or calculated glomerular capillary hydrostatic pressure from control animals. However, renal plasma flow was increased so that whole-kidney filtration fraction was low. These changes were largely reversed by choledochoduodenostomy.
5. Proximal tubular reabsorption in the jaundiced group was not different from control rats, although the inulin (urine/plasma) ratio was significantly reduced, indicating diminished reabsorption distal to the proximal convoluted tubule. Proximal intratubular hydrostatic pressure was significantly increased in some nephrons.
6. Electron microscopy of the glomeruli from the jaundiced animals revealed evidence of marked increase in activity of both epithelial and endothelial cells.
7. Rats who survive chronic obstructive jaundice for 3–4 weeks have changes in renal function and also structural changes suggestive of diminished glomerular permeability.
The Use of the Human Erythrocyte as a Model for Studying the Action of Diuretics on Sodium and Chloride Transport
Authors: Brooks B. A. , Lant A. F. 
Published: August 2015

1. The Na+ and Cl− transport systems of human erythrocytes have been compared for their sensitivities to diuretics known to act in the ascending limb of Henle's loop. In addition, chemical analogues of ‘loop’ compounds and also diuretics which act in other areas of the nephron have been examined.
2. The Na+ transport system lacks specificity with respect to inhibition by ‘loop’ diuretics and also a related chemical analogue studied at equivalent concentrations.
3. The Cl− transport system is inhibited, at low concentrations, by diuretics known to act in the ascending limb of Henle's loop.
4. Erythrocyte Cl− transport offers a useful model with which to study the biochemical action of diuretics.
Lack of Effect of Blood-Volume Expansion on Short-Circuit Current across an Isolated Toad Skin Incorporated in the Circulation of a Rat
Authors: Querido D. , Isaacson L. C. 
Published: August 2015

1. Evidence for the existence of ‘natriuretic hormone’ resides, in part, in the demonstration that blood volume expansion in the dog is followed by a transient fall in short-circuit current (SCC) across a frog skin incorporated within its circulation.
2. We have attempted to confirm this effect in the rat, with a toad skin (Xenopus laevis) incorporated within the circulation. The skins, bathed in whole rat blood, displayed low SCC; skins bathed in ‘mammalian’ Ringer solution displayed equally low SCC, but responded normally to pitressin or amiloride.
3. When volume expansion was induced in ten rats by infusion of equilibrated whole blood (28 ml/kg body weight) there was a brisk rise in systemic blood pressure, diuresis, natriuresis and kaliuresis.
4. This blood-volume expansion was without detectable effect on the SCC across the skins incorporated within the rats' circulations.
Urinary Kallikrein Excretion and Plasma Renin Activity in Patients with Essential Hypertension and Primary Aldosteronism
Authors: Lechi A. , Covi G. , Lechi C. , Corgnati A. , Arosio E. , Zatti M. , Scuro L. A. 
Published: August 2015

1. The 24 h urinary excretion of kallikrein has been studied in 40 normotensive control subjects and in 74 age-matched patients with essential hypertension under similar conditions. By use of the renin-sodium index, hypertensive patients were divided into two subgroups: low-renin hypertension and normal-renin hypertension patients. Urinary kallikrein determinations were also obtained from six hypertensive patients with primary aldosteronism.
2. Urinary kallikrein was significantly lower both in patients with normal-renin and low-renin essential hypertension. Urinary kallikrein excretion was very high in the patients with primary aldosteronism.
3. In nine hypertensive patients β-adrenoreceptor-blocking therapy caused a significant decrease of plasma renin activity, but had no significant effect on urinary kallikrein excretion.
4. The results support the concept that low urinary kallikrein is likely to be a marker of essential hypertension. Under certain conditions its excretion is positively related to mineralocorticoid hormone concentrations but it is not primarily related to the renin-angiotensin system.
Determinants of High Blood Pressure in Salt-Deprived Renal Hypertensive Rats: Role of Changes in Plasma Volume, Extracellular Fluid Volume and Plasma Angiotensin II
Authors: Mourant A. J. 
Published: August 2015

1. Rats with indwelling aortic and right atrial cannulae were maintained on a sodium-free diet before and after renal arterial constriction combined with contralateral nephrectomy. Control animals underwent the same protocol except that non-constricting clips were used.
2. Plasma volumes in the salt-deprived animals were lower than previously determined values in animals with free access to sodium. After clipping plasma volume increased in the hypertensive animals. Extracellular fluid volume was increased equally in both normotensive and hypertensive animals on the second postoperative day only.
3. Before clipping and contralateral nephrectomy plasma angiotensin II values were higher than normal. After the operation angiotensin II concentrations fell to normal over a period of 14 days without significant differences between experimental and control groups.
4. It is concluded that high blood pressure after clipping may be in part maintained by increases in plasma volume. However, the results strongly suggest that other renal mechanisms are likely to be of major pathogenic importance.