bluuebunny/crossref_metadata_2025_split huggingface dataset:
Circulating hyaluronate: Concentration in different vascular beds in man
Authors: Bentsen Kirsten D. , Henriksen Jens H. , Laurent Torvard C. 
Published: August 2015

1. The plasma concentration of hyaluronate (hyaluronic acid; HA) was measured in different vascular beds in order to determine regional kinetics of endogenous HA in fasting, supine subjects with normal (n = 6) or moderately decreased kidney function (n = 9).
2. In both groups hepatic venous HA was significantly below the value obtained in plasma from pulmonary artery, inferior vena cava, and renal veins (P &lt; 0.001), giving a net hepato-splanchnic extraction ratio of HA about 33%.
3. The concentration of HA in renal veins was significantly below that of the pulmonary artery and inferior vena cava (P &lt; 0.05). Average net renal extraction ratio of HA in normal kidneys was approximately 20%. Unilateral kidney function was assessed by 131I-hippuran renography, and the kidney with better function had a significantly higher extraction ratio when compared with the kidney with the lower function (P &lt; 0.025). HA was inversely correlated to glomerular filtration rate (r = − 0.59, P &lt; 0.02).
4. Assuming a plasma flow of 800 and 600 ml/min in normal liver and kidneys, respectively, the average normal plasma clearances of HA in these organs in the resting subject may be estimated to be 250 and 120 ml/min, respectively.
5. The results indicate that the hepato-splanchnic region normally plays a major role in the bio-degradation of endogenous circulating HA. The kidneys also eliminate the compound, presumably the low-molecular-weight fraction of the material. The results may explain abnormally high values of circulating HA in patients with diseases in these organs.
The effect of tobacco smoke upon airway secretion in the cat
Authors: Peatfield A. C. , Davies Julia R. , Richardson P. S. 
Published: August 2015

1. We have collected secretions from a segment of trachea in the neck of cats anaesthetized with chloralose. At the start of experiments sodium [35S]sulphate and [3H]glucose were given into the segment to radiolabel secretions by biosynthesis. Subsequently, changes in output of radiolabelled macromolecules were used to indicate changes in mucin secretion rate.
2. Cigarette smoke, diluted to 10% by volume, was passed through the larynx or through the tracheal segment, or given into the lower airway. Control insufflations of air were given by the same routes.
3. When cigarette smoke was passed through the larynx, it did not change the secretion rate of radio-labelled mucins into the tracheal segment.
4. Cigarette smoke, given directly into the tracheal segment, stimulated the output of 35S-labelled mucins. Cutting the autonomic nerves to the segment failed to alter the response to cigarette smoke, but ganglion blockade with pentolinium abolished it.
5. Cigarette smoke given into the lower airways and lungs stimulated the output of radiolabelled mucins into the segment. Denervation of the segment failed to prevent this, but ganglion blockade abolished the response.
6. Measurements of plasma nicotine concentrations in some experiments showed that nicotine was absorbed from smoke in the lower airway and also suggested some absorption of nicotine from the tracheal segment.
7. We conclude that nicotine, absorbed either directly into the tracheal wall or via the blood, can stimulate the autonomic ganglia which innervate airway submucosal mucous glands. This mechanism outweighed the effect of airway irritant reflexes in these experiments.
Reduced number of angiotensin II receptors on platelets in insulin-dependent diabetes
Authors: Connell J. M. C. , Ding Yu-An , Fisher B. M. , Frier B. M. , Semple P. F. 
Published: August 2015

1. Angiotensin II receptors on platelets were studied in 13 patients with uncomplicated type I diabetes mellitus and in 15 age-matched normal subjects.
2. Receptor density on cells from the diabetic patients was 15% lower than the normal subjects (5.2 ± 0.8 sd sites/platelet in diabetic patients and 6.4 ± 0.8 in normals, P &lt; 0.001), but there were no differences in receptor affinity as measured by Kd (4.9 ± 1.5 × 10−10 mol/l in diabetic patients and 5.4 ± 1.4 × 10−10 mol/l in normals).
3. Plasma concentrations of renin and angiotensin II were similar in both groups.
4. The reduced density of angiotensin II receptors on platelets from patients with insulin-dependent diabetes may reflect a generalized abnormality of angiotensin II receptor regulation.
Ribonucleic acid turnover in man: RNA catabolites in urine as measure for the metabolism of each of the three major species of RNA
Authors: Sander Gernot , Topp Heinrich , Heller-Schöch Gesa , Wieland Jan , Schöch Gerhard 
Published: August 2015

1. Urinary excretion of the non-reusable modified RNA catabolites pseudouridine (ψ), 7-methylguanine (m7Gua) and N2,N2-dimethylguanosine (m22Guo) was measured in preterm infants and in adults. The values (in μmol/mmol of creatinine) were: for preterm and ‘small for gestational age’ infants (n = 26; number of samples = 38) ψ = 164 (sd 32), m7Gua = 39.1 (sd 9.0), m22Guo = 10.6 (sd 2.1); for adults (n = 32) ψ = 25.3 (sd 3.1), m7Gua = 4.8 (sd 0.89), m22Guo = 1.53 (sd 0.42).
2. Our measurements were compared with an expectation derived from the average cellular distribution of ψ, m7Gua and m22Guo between rRNA, tRNA and mRNA. m22Guo occurs exclusively in iRNA, ψ in both rRNA and tRNA, and m7Gua in all three RNA classes, in proportions which can be estimated for the steady state. Urinary excretion of ψ and m22Guo should reflect their steady-state distribution, since rRNA and tRNA have been shown to have similar turnover rates in mammalian tissues.
3. We conclude that we can use the excretion of m22Guo to assess whole-body tRNA turnover. Since tRNA contains ψ constant proportion to m22Guo, the proportion of urinary ψ stemming from tRNA can be estimated, and the remainder (~ 60–65%) is an indicator of rRNA turnover. Finally, the excretion of m7Gua far exceeds the proportion predicted to come from rRNA and tRNA. We ascribe this excess (~ 60–70% of the total) to the turnover of the mRNA ‘cap’-structure, which is typical for all higher organisms. mRNA turnover is known to be much higher than that of rRNA or tRNA.
4. Calculated average RNA turnover rates (in μmol day−1 kg−1 body weight) were: for preterm infants 0.1 rRNA, 1.93 tRNA, 2.44 mRNA-‘cap’; for adults 0.037 rRNA, 0.63 tRNA, 0.62 mRNA-‘cap’.
5. Estimation of RNA turnover rates may supplement the hitherto more widely used 15N tracer studies in assessing whole-body metabolic state. Results obtained up to now closely agree with the findings from 15N tracer studies (approximately threefold higher turnover rates in preterm infants than in adults). This is probably correlated with the fact that RNA is intimately involved in all steps of protein synthesis.
The effect of polyethylene glycol by gavage on electrolyte and water excretion in the rat
Authors: Sonkodi S. , Tichy B. , Brown W. B. , Robertson J. I. S. 
Published: August 2015

1. The effects of polyethylene glycol (PEG) 200 administered by gavage on electrolyte and water excretion were investigated in the rat.
2. PEG 200 led, in intact rats, to dose-related increased drinking and to diuresis.
3. In the first 2 h after PEG 200 administration, water consumption in intact rats exceeded urine output.
4. PEG 200 enhanced the excretion of both sodium and potassium, but the sodium excretion was proportionately greater, resulting in an elevation of the urinary sodium/potassium ratio.
5. Bilateral nephrectomy was not accompanied by increased drinking in PEG 200-treated rats, although raised serum osmolality was seen.
6. Thus, given by gavage, PEG 200 is not an inert vehicle for drug administration.
Urinary kallikrein response to repeated frusemide injections in rats: Effect of adrenalectomy and deoxycorticosterone acetate treatment
Authors: Obika L. F. O. , Marin-Grez M. 
Published: August 2015

1. The effect of repeated intravenous injections of frusemide (0.17 mg/kg) on the urinary kallikrein excretion of normal, adrenalectomized and deoxycorticosterone acetate (D0CA)-treated adrenalectomized rats was studied.
2. Adrenalectomy decreased baseline urinary kallikrein excretion, while DOCA treatment restored it to normal.
3. Frusemide injections repeatedly increased urinary kallikrein excretion in the three groups of rats studied. Compared with control and DOCA-treated animals, adrenalectomized rats were less responsive.
4. The excretion of urinary kallikrein was positively correlated with urine volume and with the excretion of sodium and potassium in all groups. The regression lines were shifted to the left in DOCA-treated adrenalectomized rats showing that mineralocorticoids enhance the effect of frusemide on urinary kallikrein excretion. The regression lines between urinary kallikrein excretion and the measured variables in adrenalectomized rats did not differ from those of control animals.
5. We conclude that the response of urinary kallikrein to frusemide is influenced by the level of mineralocorticoid activity. The effect of frusemide on urinary kallikrein excretion does not appear to be a ‘wash-out’ of the enzyme since its influence did not subside after repeated injections.
The contribution of PGI2 to the effects of captopril in conscious dogs in differing states of sodium balance
Authors: Watson Michael L. , Jones Robert L. 
Published: August 2015

1. There is some evidence that increased prostaglandin synthesis may mediate some of the effects of the angiotensin converting enzyme inhibitor captopril.
2. The potential role of prostaglandin (PG)I2 in this process was assessed by measurement of changes in urinary 6-keto-PGF1α excretion after captopril in eight sodium replete and depleted conscious dogs.
3. In sodium replete animals captopril induced a small decrease in blood pressure, transient increases in effective renal plasma flow and urinary 6-keto-PGF1α excretion, and progressive increases in plasma renin activity (PRA) and urinary sodium excretion.
4. By contrast, during sodium depletion captopril induced a large decrease in blood pressure, a transient increase in effective renal plasma flow and urinary 6-keto-PGF1α excretion, an early large but transient increase in PRA and small progressive increase in sodium excretion.
5. The time course of changes after captopril suggested that increased PGI2 synthesis may contribute to the transient decrease in renal vascular resistance.
6. The increase in PRA during sodium depletion was not associated with any change in urinary 6-keto-PGF1α excretion.
Inherited variations in glomerular handling of antigen between Lewis and DA rats
Authors: Jones J. M. Boulton , Chandrachud Lata , Mosely Hannah 
Published: August 2015

1. Inherited differences in the quantity and site of renal deposition of antigen were studied in two inbred strains of healthy rats, one of which, Lewis, is susceptible to Heymann's nephritis and the other (DA) is resistant.
2. Deposition of human cationic immunoglobulin G (IgG) was significantly less in the liver, spleen and kidneys of Lewis rats compared with DA rats, which suggests that the density of the negatively charged molecules in the capillary walls of Lewis rats is less than in DA rats. Immunofluorescent studies of the kidneys 15 min after administration of cationic IgG showed that it could be detected only on the glomerular basement membrane (GBM) and that the intensity of the deposits was less in Lewis rats.
3. The mesangial uptake of aggregated IgG was greater in DA rats at all times studied. There was remarkable similarity in the glomerular processing of cationic IgG and aggregated IgG in both strains.
4. These differences in glomerular properties, capillary charge and mesangial uptake may lead to differences in the deposition of antigen within the glomerulus and in the response to the subsequent inflammatory reactions. This provides a new hypothesis for genetic predisposition of individuals to particular glomerulopathies.
Compensatory spleen growth and protective function in rats
Authors: Van Wyck David B. , Witte Marlys H. , Witte Charles L. 
Published: August 2015

1. To quantify compensatory spleen growth after reduction in splenic mass and to determine the effect of age and vascular supply on remnant growth, we examined adult and weanling rats for remnant regeneration and adult rats for host protection against bloodstream pneumococcal challenge at intervals up to 180 days after partial resection or autograft implantation.
2. In adults, subtotally resected spleens with remnant blood flow and segmental anatomy otherwise intact (eutopic remnants) displayed prompt but relatively limited gains in remnant weight and nucleated cell number, and growth after 60 days was minimal; survival after pneumococcal challenge was directly related to initial remnant weight and unrelated to length of postoperative interval. Splenic autografts (ectopic remnants), by comparison, underwent necrosis early after devascularization, recovered initial remnant weight slowly, fell far short of restoring original cellularity, and even 6 months after implantation barely attained initial size; moreover, host protection against pneumococcaemia was no different in rats with autografts than in those with no residual spleen. Remnants in situ (both partial resection and whole spleens) grew more vigorously in weanling than adult rats.
3. The results suggest that splenic regeneration after either partial resection or implantation is much more limited than previously suggested, at least in disease-free rats, and is regulated by size and integrity of the initial remnant spleen, adequacy of vascular inflow, and age of the host. Whereas eutopic remnants provide protection against blood-borne pneumococcal challenge in proportion to initial residual size, ectopic remnants even with prolonged maturation fail to display immunoprotective function.
Development and application of a superfusion technique for the study of renin secretion in rat renal cortical cells
Authors: Drury P. L. , Williams B. C. , Edwards C. R. W. , Oddie C. J. , Horne B. 
Published: August 2015

1. A dynamic column superfusion system has been developed for the study of renin secretion in rat renal cortical cells.
2. Cells were isolated by collagenase digestion and mechanical dispersion, before suspension with polyacrylamide beads and superfusion with oxygenated physiological medium.
3. Renin was detected in the superfusate by incubation of fractions with excess nephrectomized sheep substrate in the presence of angiotensinase inhibitors followed by radioimmunoassay of the angiotensin I generated.
4. Optimized methodology included a purposebuilt polytetrafluorethylene flow cell, a 1 h equilibration to achieve a steady state, 5 min eluate collections, a 15 min stimulatory and a 30 min recovery period, and duration of perfusion of up to 270 min.
5. Significant increments above baseline renin release were seen with the stimuli of adrenaline, noradrenaline and isoprenaline. These could be demonstrated with concentrations of 10−9 mol/l (adrenaline), 5 × 1O−10 mol/l (noradrenaline) and 1O−9 mol/l (isoprenaline).
6. This technique has significant advantages over previous methods for the study of renin secretion in vitro at the cellular level. It is reproducible and sensitive, and avoids many of the limitations of static cell suspension and kidney slice methods.
Fatty acid synthesis in vitro by liver tissue from control subjects and patients with alcoholic liver disease
Authors: Venkatesan S. , Leung Nancy W. Y. , Peters Timothy J. 
Published: August 2015

1. Percutaneous liver biopsy specimens were obtained from 11 control subjects, 24 alcoholic patients and six diabetic patients with mild to severe fatty liver and incubated in Krebs–Henseleit buffer containing 3H2O. The incorporation of 3H into fatty acid was measured and the absolute rate of fatty acid synthesis calculated.
2. Fatty acid synthesis rates were significantly lower in alcoholic fatty liver than in controls.
3. Fatty acid synthesis rates were similar in controls and patients with diabetic fatty livers.
4. Addition of 50 mmol/l ethanol did not alter the fatty acid synthesis rates in vitro. It is concluded that enhanced lipogenesis is not the major cause of fatty liver in patients with alcoholic fatty liver.
Exaggerated responsiveness of immunoreactive atrial natriuretic peptide to saline infusion in chronic renal failure
Authors: Walker Robert G. , Swainson Charles P. , Yandle Tim G. , Nicholls M. Gary , Espiner Eric A. 
Published: August 2015

1. Plasma levels of immunoreactive alpha human atrial natriuretic peptide (IR-ANP) were measured in nine patients with chronic renal failure before and after removal of 1.3–3.7 litres of fluid by ultrafiltration and again during volume repletion with intravenous sodium chloride solution (150 mmol/l: saline).
2. Baseline levels of IR-ANP were elevated but fell by 22% during ultrafiltration.
3. Saline infusion induced a rapid and steep rise in IR-ANP levels which were 150% of baseline while body weight was still 2% below baseline.
4. Changes in plasma renin, angiotensin II, aldosterone and vasopressin during the study were slight compared with the change in IR-ANP, but noradrenaline levels rose threefold during ultrafiltration.
5. There was a significant positive relationship between arterial pressure and IR-ANP levels before and after ultrafiltration.
6. These results lend support to the suggestion that atrial peptides are of physiological importance, especially in states of chronic fluid overload such as chronic renal failure.
Atrial natriuretic peptide inhibits the effect of endogenous angiotensin II on plasma aldosterone in conscious sodium-depleted rats
Authors: Chartier Lynn , Schiffrin Ernesto L. 
Published: August 2015

1. Previous studies have shown that atrial natriuretic peptide (ANP) inhibits the secretion of aldosterone by isolated adrenal glomerulosa cells stimulated by angiotensin II, adrenocorticotropic hormone and potassium in vitro. We have also demonstrated that this inhibitory effect of ANP on plasma aldosterone induced by angiotensin II and adrenocorticotropic hormone can be reproduced in vivo in conscious unrestrained rats. In this study, we have investigated the effect of an intravenous infusion of ANP on plasma aldosterone in conscious unrestrained sodium-depleted rats.
2. During sodium depletion, the rise in plasma renin activity which determines an increment in the circulating concentration of angiotensin II was accompanied by a rise in aldosterone secretion as expected. ANP infused intravenously at a dose which increased the plasma concentration of the peptide three- to five-fold, produced a significant decrement in the concentration of aldosterone in plasma after an infusion period of 120 min. There was no significant effect of ANP on plasma renin activity and plasma corticosterone concentration.
3. Since the increase in plasma aldosterone levels in sodium-depleted rats is mainly dependent on the activation of the renin–angiotensin system, we conclude that ANP may modulate the effect of endogenous as well as exogenous angiotensin II on plasma aldosterone secretion.
Vasoactive intestinal peptide: A direct renal natriuretic substance
Authors: Duggan K. A. , MacDonald G. J. 
Published: August 2015

1. To establish whether or not vasoactive intestinal peptide (VIP) acts directly on the kidney and also to define the renal responses to it, we compared the natriuretic and haemodynamic responses to VIP (10−4–100 pmol min−1 kg−1) infused intravenously with those obtained by direct infusion into the renal artery in seven conscious male rabbits.
2. VIP had significant effects on the renal circulation without changing systemic arterial pressure or pulse rate. There was a significant fall from control in effective renal plasma flow (P &lt; 0.05 renal infusion, P &lt; 0.01 intravenous infusion) and glomerular filtration rate (P &lt; 0.01 renal, P &lt; 0.05 intravenous). The derived renal vascular resistance rose significantly from control (P &lt; 0.01 renal, P &lt; 0.01 intravenous).
3. Despite the significant decline in filtered sodium load (P &lt; 0.01 renal, P &lt; 0.001 intravenous), there was a significant log dose-related increase in fractional sodium excretion (P &lt; 0.005) with intrarenal infusion of VIP.
4. We conclude that the actions of VIP on intrarenal blood vessels and renal tubules are direct, leading to increases in renal vascular resistance and fractional sodium excretion.
The relationship between intestinal crypt cell production and intestinal water absorption measured in vitro in the rat
Authors: Goodlad R. A. , Plumb J. A. , Wright N. A. 
Published: August 2015

1. In studies on intestinal adaptation it is often important to obtain contemporaneous data on the rate of cell production and the functional status of the intestine.
2. The measure of the rate of accumulation of vincristine arrested metaphases in microdissected intestinal crypts to determine the crypt cell production rate (CCPR), is one of the most effective methods of estimating intestinal epithelial cell proliferation which is robust enough to withstand scrutiny. However, studies in the field of intestinal adaptation could be much more informative if a valid measure of intestinal function could also be included. One such method is the water absorption capacity in vitro.
3. The intraperitoneal injection of vincristine sulphate (1 mg/kg) had no significant effect on the water absorption capacity of the small intestine, as measured by the segmented flow single pass perfusion method; thus the CCPR of the jejunum and intestinal water absorption were both measured in 19 groups of hypo- and hyper-proliferative rats which should have been in a relatively ‘steady state’ of cell production and turnover.
4. The minimum values were obtained after hypophysectomy and the maximum values were observed in lactation. CCPR and absorption were significantly correlated (P &lt; 0.001) with each other. There was a significant (P &lt; 0.001) correlation between both CCPR and absorption and dry weight of the intestinal segment studies with food intake. Body weight was a poor predictor of either CCPR or absorption.
5. The combined study of CCPR and water absorption is a practical and convenient approach to the study of intestinal cell proliferation and intestinal adaptation, and shows that in ‘steady state’ models of hypoplasia and hyperplasia, cell production is closely linked to functional capacity and both of these are also related to the food intake.
The effect of muscle paralysis on the radial growth of collagen fibrils in developing tendon
Authors: Scott Pr J. E. , Haigh Marion , Neo Geok-Eng , Gibson Sarah 
Published: August 2015

1. Voluntary muscle activity in chick embryos was paralysed by administration in ovo of tubocurarine hydrochloride, administered in single or multiple doses, from day 9 to day 13 after fertilization. Control eggs were given saline instead of tubocurarine or were simply incubated without operative interference. Embryos were killed at 9, 13, 14, 16 and 19 days after fertilization. Flexor digitorum tendons were removed, fixed in glutaraldehyde, embedded in plastic, sectioned, and stained with phosphotungstic acid for electron microscopy. The diameters of the tendon collagen fibrils were measured, on electron micrographs, using a Magiscan Mk II programme.
2. Tendon collagen fibril expansion was not inhibited by tubocurarine treatment. It is concluded that the rapid increase of collagen fibril diameters, which coincides in the normal embryo with the first onset of use of the associated muscle, is not dependent on muscle activity. There remains a possibility that other ways of producing tension in the tendon could provide sufficient stimulus to fibril expansion.