bluuebunny/crossref_metadata_2025 huggingface dataset:
Breathlessness during different forms of ventilatory stimulation: a study of mechanisms in normal subjects and respiratory patients
Authors: Adams L. , Lane R. , Shea S. A. , Cockcroft A. , Guz A.
Published: August 2015

1. This study investigates the mechanisms underlying the perception of breathlessness induced by hypoxia and hypercapnia in both naive normal subjects and patients with respiratory mechanical problems.

2. In normal subjects separately receiving both oscillating hypercapnic and hypoxic ventilatory stimulation, equivalent peak stimulus intensities in end-tidal gas were associated with a ‘damped’ ventilatory response when the frequency of stimulation was increased. A concomitant fall in peak breathlessness levels on a visual analogue scale was recorded in each case.

3. In normal subjects and patients, the voluntary copying of a ventilatory pattern recorded during oscillating hypercapnic stimulation was associated with a marked diminution or complete absence of breathlessness despite equivalent levels of peak ventilations achieved.

4. Voluntary copying of hypercapnic stimulated ventilation was not associated with any demonstrable change in the distribution of muscle movements between the chest wall and abdomen.

5. These results suggest that the intensity of breathlessness depends on the level of effective reflex stimulation of the respiratory-related neurones in the medulla. They cannot be explained solely in terms of perception of afferent neural information arising from either chemoreceptors or respiratory mechanoreceptors.
Evaluation of glycerol as an osmotic agent for continuous ambulatory peritoneal dialysis in end-stage renal failure
Authors: Heaton A. , Ward M. K. , Johnston D. G. , Alberti K. G. M. M. , Kerr D. N. S.
Published: August 2015

1. Six patients established on continuous ambulatory peritoneal dialysis entered a trial of treatment with dialysis fluid containing glycerol instead of glucose as the osmotic agent in an attempt to decrease the energy load. They were observed for a further 6 months after reconversion to glucose-based dialysis.

2. During the 6 month control period fluid balance was achieved mainly with a solution containing 76 mmol of glucose/l. Fluid balance was maintained during the 6 month period of treatment with glycerol only by the increased use of solutions containing a high concentration of glycerol (152 mmol/l and 272 mmol/l). Thus the energy value of the absorbed osmotic agent did not differ at a mean of 1607 kJ (384 kcal)/day using glycerol and 1669 kJ (399 kcal)/day using glucose as the osmotic agent.

3. In five subjects, fasting and peak blood glycerol levels did not change over the 6 months, but one subject, who accumulated glycerol, developed symptoms of hyperosmolality after 2 months and glycerol therapy was discontinued. In a further subject glycerol-based dialysis was terminated at 3 months when increasing angina was reported.

4. Mean fasting plasma triglyceride concentrations were 50% higher during the 6 months on glycerol (3.12 ± 1.12 mmol/l) than on glucose (2.19 ± 0.97 mmol/l) (P < 0.05). There was a small rise in very low density lipoprotein-cholesterol concentrations with glycerol dialysis but total cholesterol levels were unchanged.

5. The absorption of glycerol was not associated with an acute rise in circulating glucose or insulin but the mean blood glucose, over a 6 h dialysis cycle, had risen by 0.5 mmol/l after 3 months' treatment with glycerol and the mean serum insulin had risen from 5.9 ± 0.7 m-units/l to 9.8 ± 0.6 m-units/l (P < 0.01).

6. This study demonstrated no substantial advantage of glycerol over glucose as an osmotic agent in non-diabetic patients on continuous ambulatory peritoneal dialysis.
Abnormalities of peripheral venous tone in women with pregnancy-induced hypertension
Authors: Stainer Karen , Morrison Rachel , Pickles C. , Cowley A. J.
Published: August 2015

1. Forearm venous tone was measured in two groups of pregnant women: one group with pregnancy-induced hypertension and the other group with normal blood pressure.

2. The women with pregnancy-induced hypertension were venoconstricted in the forearm (P < 0.01) compared with the pregnant women with normal blood pressure. However, there was no difference in venous tone between the women with pregnancy-induced hypertension and nonpregnant women.

3. There was an inverse correlation between mean arterial blood pressure and forearm venous tone (r = −0.581, P < 0.001) for all the pregnant women studied. Further evaluation of peripheral venous tone may provide valuable information about the pathophysiology and treatment of women with pregnancy-induced hypertension.
Antihypertensive effects of S9490-3, a new converting enzyme inhibitor, in the conscious spontaneously hypertensive rat
Authors: Barres C. , Cerutti C. , Paultre C. Z. , Sassard J.
Published: August 2015

1. The acute and chronic cardiovascular effects of S9490-3, a new converting enzyme inhibitor, were studied by means of a computerized analysis of the intra-aortic blood pressure recorded for 48 consecutive hours, in the conscious, unrestrained adult spontaneously hypertensive rat (SHR). The software used allowed the simultaneous study of one control and one treated animal.

2. A single intravenous dose of S9490-3 (2 mg/kg) induced a rapid fall in systolic and diastolic blood pressure, which remained significant for 11 h. This decrease was not associated with an elevation in heart rate.

3. A chronic oral treatment with S9490-3 (1 mg/kg/24h for 12 days) significantly lowered systolic and diastolic blood pressure and reduced the variability of systolic blood pressure. The heart rate was slightly increased at rest (day time) but significantly elevated in the freely exercising SHR (night time). However, it must be noted that this increase remained moderate.

4. The baroreflex sensitivity of chronically treated animals was enhanced when measured after phenylephrine but not after nitroglycerine bolus.

5. Chronically given S9490-3 significantly reduced the pressor effect of phenylephrine and decreased the left ventricle weight.
Cardiovascular and metabolic responses to low dose adrenaline infusion: an invasive study in humans
Authors: Freyschuss U. , Hjemdahl P. , Juhlin-Dannfelt A. , Linde B.
Published: August 2015

1. Cardiovascular and metabolic responses to intravenous infusions of adrenaline (ADR), which raised arterial plasma ADR in a stepwise fashion from 0.3 to 1.3, 2.3 and 6.0 nmol/l, were studied in 11 healthy volunteers.

2. ADR evoked marked and concentration-dependent increases in stroke volume and cardiac output (thermodilution), as well as decreases in the vascular resistances of the systemic circulation, calf and adipose tissue. These changes were significant from 1.3 nmol/l ADR. Less marked effects were found on blood pressure and heart rate.

3. Significant arterial ADR concentration-effect relationships were found for cyclic AMP, glycerol, glucose, lactate and noradrenaline, but not for insulin. Cyclic AMP and glycerol were significantly elevated at 1.3, glucose at 2.3, but lactate not below 6.0 nmol/l ADR. Increases in adipose tissue blood flow and arterial glycerol levels were correlated (P < 0.001), suggesting a metabolic component in the blood flow response of adipose tissue.

4. Invasive haemodynamic measurements revealed that ADR at arterial concentrations within the lower physiological range had considerable effects on cardiac output and vascular resistances, despite moderate changes in the conventional non-invasive haemodynamic variables blood pressure and heart rate.

5. ADR elicited clear-cut responses at arterial plasma concentrations attained during various kinds of mild to moderate stress.
Diffusion of butyrate through pig colonic mucus in vitro
Authors: Smith Gavin W. , Wiggins Philippa M. , Lee Sum P. , Tasman-Jones Clifford
Published: August 2015

1. Using a modified equilibrium dialysis cell the rate of diffusion of butyrate through pig colonic mucus has been compared with that through other gels and unstirred layers.

2. Relative diffusion coefficients were calculated for each layer. Layers of 8% polyacrylamide, and of caecal, mid-colonic and terminal colonic mucus, had coefficients that were 50–60% of the apparent free diffusion coefficient for butyrate, determined using layers made up of Millipore filters alone.

3. The apparent free diffusion coefficients for butyrate (layers of agarose or filters) were 70% of previously determined values in the literature. This discrepancy can be explained by elements of the experimental procedure.

4. All mucus layers differed significantly from layers of 2% agarose and Millipore filters but were not significantly different from layers of 8% polyacrylamide or from each other.

5. Diffusion coefficients for butyrate in the mucus samples correlated with water content and carbohydrate content but had no relationship to protein content.

6. The rate of diffusion of butyrate in colonic mucus layers was significantly reduced when compared with unstirred layers (P < 0.05). Whether this has an effect on the butyrate supply to colonocytes in vitro and whether mucus in colonic disease behaves differently are subjects for further investigation.
Changes in bone and muscle constituents during dieting for obesity
Authors: Davie Michael W. J. , Abraham Ralph R. , Hewins Belinda , Wynn Victor
Published: August 2015

1. The effects of dietary carbohydrate (CHO) content and of tri-iodothyronine (T3) administration on calcium, zinc and phosphate balances and on urinary hydroxyproline output were examined in eight obese subjects undergoing therapy with low energy (2741–3301 kJ/day), high calcium (28.9–35.1 mmol/day) diets.

2. Calcium balances were generally positive at the high levels of intake used, but significantly more calcium was retained when dietary CHO intake (as proportion of total energy intake) was increased.

3. Zinc balances were more positive when the proportion of dietary CHO was high and correlated both with nitrogen balance and with daytime insulin concentration.

4. Urinary hydroxyproline output generally increased with dieting irrespective of dietary CHO content.

5. Administration of T3 (30–80 μg/day) markedly increased zinc loss without affecting calcium balance.
Eel calcitonin suppresses plasma human calcitonin levels in medullary carcinoma of the thyroid
Authors: Morimoto S. , Miyauchi A. , Fukuo K. , Imanaka S. , Yamamoto H. , Tsuchiya H. , Koh E. , Yukawa S. , Onishi T. , Avioli L. V. , Kumahara Y.
Published: August 2015

1. The effects of synthetic [Asu1,7]-eel calcitonin (0.5 MRC unit/kg body weight intravenously for 30 min) on circulating levels of human calcitonin, calcium and gastrin were investigated in five patients with medullary carcinoma of the thyroid.

2. Blood samples were obtained before and 15, 30, 60, 90, 120 and 180 min after commencement of infusion of [Asu1,7]-eel calcitonin. Plasma levels of human calcitonin were measured by radioimmunoassay. Cross-reactivity with [Asu1,7]-eel calcitonin in this assay was negligible.

3. On infusion of [Asu1,7]-eel calcitonin, the mean plasma level of human calcitonin decreased significantly to 71.0 ± 8.7% of the basal level (mean ± sem, P < 0.05) after 30 min and 68.4 ± 25.4% of the basal level (P < 0.05) after 60 min. The serum calcium level also decreased significantly, but lagged behind the decrease of human calcitonin, being 95.1 ± 0.7% of the basal level (P < 0.01) at 120 min and 94.8 ± 0.6% of the basal level (P < 0.02) at 180 min. The mean plasma gastrin level did not change significantly on infusion of [Asu1,7]-eel calcitonin.

4. In pooled data for all times, the percentage change in human calcitonin was not significantly correlated with either the percentage change in calcium (r = −0.25, P > 0.1) or the percentage change in gastrin (r = −0.3 8, P > 0.1).

5. These data suggested that [Asu1,7]-eel calcitonin suppressed calcitonin secretion in patients with medullary carcinoma of the thyroid. The mechanism of its effect is unknown.
Human calcitonin gene related peptide: a potent endogenous vasodilator in man
Authors: Struthers A. D. , Brown M. J. , Macdonald D. W. R. , Beacham J. L. , Stevenson J. C. , Morris H. R. , Macintyre I.
Published: August 2015

1. In addition to calcitonin and katacalcin, it is now known that the human calcitonin gene encodes a novel peptide called calcitonin gene related peptide (CGRP). In experimental animals, CGRP produces vasodilatation and complex changes in plasma calcium.

2. We have now assessed its biological activity in man by infusing human CGRP (hCGRP) into six normal volunteers. hCGRP (545 pmol/min) caused the diastolic pressure to fall from 64 ± 5 to 55 ± 7mmHg (P < 0.05), the heart rate to increase from 61 ± 7 to 87 ± 5 beats/min (P < 0.05) and the skin temperature to increase from 33.7 ± 0.9 to 34.9 ± 0.5°C. Plasma noradrenaline increased from 481 ± 126 to 835 ± 65 pg/ml (P < 0.05) and plasma adrenaline from 57 ± 17 to 82 ± 12 pg/ml (P < 0.05). There were no significant changes in the albumin-corrected plasma calcium.

3. hCGRP is thus a potent endogenous vasodilator in man and is in fact more potent than any other known vasodilator. Together with the observations that CGRP circulates in normal subjects at relatively high concentration (approximately 25 pmol/l) and that CGRP is present in perivascular nerves, this study suggests a possible role for CGRP in controlling peripheral vascular tone in man.
Effects of verapamil alone and with captopril on blood pressure and bilateral renal function in Goldblatt hypertensive rats
Authors: Huang Wann-Chu
Published: August 2015

1. The effects of verapamil infusion alone and superimposed with captopril on arterial pressure and bilateral renal function were evaluated in 21 two-kidney, one-clip Goldblatt hypertensive rats and in 13 control rats.

2. Verapamil significantly decreased arterial pressure of both hypertensive and control rats. Addition of captopril further reduced arterial pressure in hypertensive rats only.

3. There were significant increases in glomerular filtration rate (GFR), urine flow and absolute and fractional excretory rates of sodium and potassium in the non-clipped kidney. In contrast, these renal indices decreased in the clipped kidney. Superimposed captopril during verapamil infusion did not significantly change function of the non-clipped kidney but further depressed function of the clipped kidney.

4. In control rats, no significant change in GFR occurred in response to drugs. Renal excretion of water and sodium, but not potassium, increased after verapamil. However, the diuresis and natriuresis were less pronounced than those seen in the non-clipped kidney of hypertensive rats.

5. There was a proportionate increase in osmolar clearance and free water reabsorption rate in the non-clipped kidney and the normal kidney. The linear relationship did not change after verapamil infusion.

6. The results suggest that verapamil enhances the excretory function of the non-clipped kidney of Goldblatt hypertensive rats via increased GFR and decreased tubular reabsorption in the proximal and/or distal tubules despite its hypotensive action.
Effect of indirect heating on the postural control of skin blood flow in the human foot
Authors: Hassan A. A. K. , Rayman G. , Tooke J. E.
Published: August 2015

1. It has been shown in previous studies that skin blood flow in the human foot falls when the extremity is placed below heart level, owing to an increase in precapillary resistance that is probably mediated by a local sympathetic axon reflex or a myogenic response.

2. In order to clarify the influence of the central thermoregulatory mechanisms on this local postural vasoconstrictor response, 12 normal male subjects were studied under standardized conditions, at rest and during heating of the trunk with an electric blanket.

3. Skin blood flow was measured before and during body heating using laser Doppler flowmetry with the foot maintained at heart level and placed passively 50 cm below the heart.

4. Skin blood flow and skin temperature were determined at two sites: (a) the plantar surface of the big toe, an area with a relatively large number of arteriovenous anastomoses, and (b) the dorsum of the same foot, where these anastomoses are few or absent.

5. When the foot was placed in the dependent position, skin blood flow recorded in the dorsum of the foot during indirect heating fell to a level similar to that achieved before heating. In contrast, indirect heating greatly diminished the postural fall in skin blood flow recorded in the plantar surface of the big toe.

6. In conclusion, the partial release of sympathetic vasoconstrictor tone associated with indirect heating appears to over-ride the local postural control of cutaneous vascular tone in areas where arteriovenous anastomoses are relatively numerous.
Alterations of intestinal membrane-bound enzymes in three types of hypertensive rats
Authors: Gilles-Baillien M. , Carlier P. G. , Rorive G. L.
Published: August 2015

1. Alkaline phosphatase, sucrase, Na+, K+-ATPase and Mg2+-ATPase specific activities of crude membrane fractions, prepared from duodenal, jejunal, ileal and colonic mucosa, have been estimated in three types of hypertensive rats: the spontaneously hypertensive rat (SHR), the DOCA-saline-treated rat and the renovascular rat (Goldblatt one-kidney, one-clip rat; 1K-1C). Alkaline phosphatase and sucrase specific activities have also been measured in purified jejunal brush-border membranes.

2. When compared with its normotensive age-matched control (WKY rat), the SHR has a lower activity of alkaline phosphatase in duodenal and jejunal crude membrane fractions, whereas a higher activity in colonic Na+, K+-ATPase is recorded. In purified jejunal brush-border membranes, lower alkaline phosphatase activity and higher sucrase activity were found. These differences occur in the young prehypertensive SHR as well as in the adult animal.

3. In the DOCA-treated rat, the only significant alteration in crude membrane fractions is a decreased Mg2+-ATPase activity at all regions of intestinal mucosa. In purified jejunal brush-border membranes both alkaline phosphatase and sucrase activities are increased at 4 or 7 weeks but especially at 13 weeks of hypertension.

4. In the 1K-1C rat, no significant modification appears in crude membrane fractions or in purified jejunal brush-border membranes, but a decrease in alkaline phosphatase and in sucrase activities is probable afer 13 weeks of hypertension.

5. Since alterations of the intestinal enzymes are different in the three types of hypertensive rats it is concluded that the changes are not secondary to the hypertension condition. In the SHR, these alterations are present in the young prehypertensive animal. Abnormalities of intestinal function may be implicated in the origin of genetic hypertension.

6. All recorded alterations represent 25-50% variations from control values. They indicate disturbances of intestinal ion transport in the three types of hypertensive animals.
The reproducibility of limb blood flow measurements in human volunteers at rest and after exercise by using mercury-in-Silastic strain gauge plethysmography under standardized conditions
Authors: Roberts D. H. , Tsao Y. , Breckenridge A. M.
Published: August 2015

1. A study to assess the reproducibility of limb blood flow measurements by venous occlusion plethysmography using mercury-in-Silastic strain gauges was performed in six normal volunteers under standardized conditions.

2. Using this technique forearm and calf blood flow were measured at rest and between 2 and 3 min after submaximal exercise on six separate occasions over a 1 month period.

3. The mean coefficient of variation for resting forearm blood flow was 10.5% (range 7.8-15.6%).

4. The mean coefficient of variation for resting calf blood flow was 11.5% (range 7.4-14.2%).

5. The mean coefficient of variation for post-exercise calf blood flow was 13% (range 11.5-16.4%).

6. The results suggest that limb blood flow measurement by this technique may be useful in studies where serial measurements are required.
Effect of hypertension on the progress and prognosis of experimental focal glomerular sclerosis
Authors: Okuda Seiya , Tsuruda Hiroshi , Onoyama Kaoru , Oh Yukinori , Motomura Kenichi , Fujishima Masatoshi
Published: August 2015

1. Effect of hypertension on progressive renal disease was examined in spontaneously hypertensive rats (SHR) with experimental focal glomerular sclerosis, produced by the intravenous administration of adriamycin (ADR). Serial changes of urinary protein, blood pressure and blood chemistry for 22 weeks after ADR-treatment, and renal histology at week 22, were compared between ADR-treated SHR (group ADR-HT) and ADR-treated SHR given antihypertensive drugs (group ADR-AH).

2. Hypertension persisted in group ADR-HT, while blood pressure markedly decreased in group ADR-AH, after oral administration of antihypertensive drugs (guanethidine and hydralazine).

3. Massive proteinuria, hypoalbuminaemia and hypercholesterolaemia were observed throughout the experiment both in group ADR-HT and in group ADR-AH. Urinary protein levels were significantly larger in the former at weeks 12 and 16.

4. Blood urea nitrogen and serum creatinine levels increased progressively from week 16 in the ADR-treated rats. The increase was more rapid in group ADR-HT than in group ADR-AH. In group ADR-HT, 10 of 25 rats died between weeks 20 and 22, whereas all in group ADR-AH survived.

5. Histologically, ADR-treated rats showed focal glomerular sclerosis with tubulointerstitial changes. The lesions were more extensive in group ADR-HT than in group ADR-AH.

6. We conclude that hypertension influences the progress and prognosis of chronic progressive renal disease, as induced by adriamycin.
The determination of oxalate in haemodialysate and plasma: A means to detect and study ‘hyperoxaluria’ in haemodialysed patients
Authors: Wolthers B. G. , Meijer S. , Tepper T. , Hayer M. , Elzinga H.
Published: August 2015

1. In order to find out whether hyperoxaluria can be demonstrated in patients on chronic (twice a week) haemodialysis, a group of 13 patients was investigated. These included one patient with proven primary hyperoxaluria, one suspected of having this disease and 11 patients in whom no information was available as to their oxalate metabolism.

2. Oxalate concentrations in haemodialysate fractions and blood samples, taken before and after dialysis, were determined.

3. The patient with primary hyperoxaluria had a plasma oxalate concentration before dialysis above 100 μmol/l and after dialysis above 25 μmol/l, while the oxalate concentration in haemodialysate at the start of dialysis was above 25 μmol/l and at the end above 10 μmol/l. The patient suspected of hyperoxaluria had similar values. Of the remaining 11 patients, one was shown to exhibit a transient hyperoxaluria, but the others showed a normal oxalate metabolism.

4. A plasma oxalate/creatinine concentration ratio exceeding 0.1, and the calculated total quantity of oxalate removed by dialysis exceeding 2 mmol, also enabled a diagnosis of hyperoxaluria to be made.

5. Hyperoxaluria can still be demonstrated in patients, who because of renal failure are subjected to haemodialysis. Measurements of oxalate in haemodialysate and plasma are valuable in cases where kidney transplantations are considered, especially when the particular patient exhibits hyperoxaluria.
Superoxide dismutase isoenzymes in cerebrospinal fluid and plasma from patients with neuronal ceroid-lipofuscinoses
Authors: Marklund Stefan L. , Heiskala Hannu , Westermarck Tuomas , Santavuori Pirkko
Published: August 2015

1. The neuronal ceroid-lipofuscinoses is a group of diseases characterized by a widespread accumulation in the body of pigments believed to be end-products of lipid-peroxidation damaged organelles. It was recently shown that cerebrospinal fluid from patients with infantile and juvenile neuronal ceroid-lipofuscinosis were less protective against superoxide radical-induced hydroxyl radical formation compared with controls [3].

2. The content of superoxide dismutase isoenzymes in cerebrospinal fluid and in plasma from patients with different forms of neuronal ceroid-lipofuscinosis was analysed. No significant difference from controls could be demonstrated in samples from patients with juvenile neuronal ceroid-lipofuscinosis. The few samples from patients with infantile and late infantile neuronal ceroid-lipofuscinosis analysed all fell within the range defined by the controls.
Changes in human plasma atrial natriuretic polypeptide concentration in normal subjects during passive leg raising and whole-body tilting
Authors: Ogihara Toshio , Shima Junko , Hara Hiroko , Kumahara Yuichi , Kangawa Kenji , Matsuo Hisayuki
Published: August 2015

1. The effect of central venous pressure on release of human atrial natriuretic polypeptide (hANP) was studied by measuring the plasma hANP levels during passive leg raising to 60° and head up whole-body tilt at 60° in normal volunteers.

2. In ten subjects, after at least 1 h recumbency, both legs were raised passively 60° for 20 min. While the legs were raised the plasma hANP level increased significantly from a basal level of 101 ± 10 pg/ml (mean ± se) to a peak of 165 ± 15 pg/ml after 10 min, and returned to the basal level 10 min after the legs were lowered. The blood pressure and pulse rate were not affected by raising the legs.

3. The effect of head up whole-body tilt of 60° from the supine position, for 20 min, was examined in nine normal subjects. Their plasma hANP decreased transiently at 5 min in five of them and at 10 min or later in the remaining four subjects. Their blood pressure did not change but their pulse rate increased significantly while their body was being tilted.

4. These results suggest that secretion of hANP is regulated physiologically by changes in the central venous pressure.
Systemic and regional haemodynamic effects of a synthetic atrial natriuretic peptide in conscious rats
Authors: Caramelo Carlos , Fernandez-Cruz Arturo , Villamediana Luis M. , Sanz Elias , Rodriguez-Puyol Diego , Hernando Luis , López-Novoa Jose M.
Published: August 2015

1. The effect of the intravenous injection of synthetic atrial natriuretic peptide (ANP, 2 μg) on systemic haemodynamics and blood flow to several organs has been studied in conscious rats by the radioactive microsphere technique.

2. ANP induced a 540% increase in sodium excretion and a 310% increase in urine flow. Mean arterial pressure decreased by 21 mmHg and the peripheral resistances decreased by 26%, without significant changes in cardiac output.

3. Renal blood flow increased by 37.7% and small intestine and portal blood flow increased by 39% and by 28% respectively. No other alterations in organ blood flows were observed.

4. From these data it can be concluded that atrial natriuretic peptide shows acute vascular relaxant properties, which seem to be specific for renal and mesenteric territories.
Enhanced rectal potassium secretion in chronic renal insufficiency: Evidence for large intestinal potassium adaptation in man
Authors: Sandle G. I. , Gaiger E. , Tapster S. , Goodshep T. H. J.
Published: August 2015

1. The role of the large intestine in K+ excretion in chronic renal insufficiency was studied with a rectal dialysis technique in 14 normal subjects and eight normokalaemic, normotensive patients with chronic renal insufficiency.

2. At initial intraluminal K+ concentrations of 10, 20, 30 and 45 mmol/l, net K+ secretion in patients with renal insufficiency was significantly greater than in normal subjects by approximately 1.8 μmol h−1 cm−2. The increase in net K+ secretion was more marked in those patients with creatinine clearances of less than 10 ml/rnin. In contrast, there were no significant differences in net Na+ and water transport, transmucosal potential difference and plasma aldosterone concentrations between the two groups.

3. With an initial intraluminal K+ concentration of 30 mmol/l, the addition of amiloride (final concentration 1 mmol/l) to the rectal lumen decreased net Na+ absorption and transmucosal potential difference in normal subjects by 69% (P < 0.005) and 31% (P < 0.005) respectively, and in patients with renal insufficiency by 75% (P < 0.05) and 36% (P < 0.05) respectively, but there was no change in net K+ secretion in either group.

4. These results indicate that the K+ secretory capacity of the rectal mucosa increases in chronic renal insufficiency, and the large intestine may therefore contribute to the maintenance of K+ homoeostasis as renal K+ excretion declines. Increased rectal K+ secretion in renal insufficiency occurs independently of changes in plasma K+ and aldosterone concentrations, net Na+ absorption and transmucosal potential difference, and may reflect stimulation of an active K+ secretory process.
The effect of the dihydroxylated metabolites of vitamin D and dietary phosphate restriction on bone disease in uraemic rats
Authors: Main J. , Velasco N. , Heyes S. D. , Whiting P. , Fraser R. A. , Catto G. R. D.
Published: August 2015

1. Uraemic rats maintained on either a high or a low phosphate diet for 12 weeks were allocated to one of the following oral vitamin D treatment groups and received: (a) 1,25-dihydroxycholecalciferol [1,25-(OH)2D3], (b) 24,25-dihydroxycholecalciferol [24,25-(OH)2D3], (c) both 1,25-(OH)2D3 and 24,25-(OH)2D3, or (d) no vitamin D supplements.

2. Mean serum creatinine concentrations were elevated to a similar extent in all groups. Mean serum concentrations of calcium, phosphate and alkaline phosphatase were not significantly different from normal in any of the groups.

3. In the group receiving the high phosphate diet and no vitamin D supplements, calcified bone area measured by quantitative computerized histomorphometry was significantly lower than in (i) the group receiving the low phosphate diet and no vitamin D supplements (0.01 > P > 0.001), and in (ii) the groups receiving high phosphate diet and either 1,25-(OH)2D3 (0.01 > P > 0.001) or 24,25-(OH)2D3 (0.01 > P > 0.001).

4. We conclude that (i) uraemic rats maintained on a high phosphate diet for 12 weeks develop skeletal demineralization, (ii) this process does not occur in rats on a low phosphate diet, and (iii) a decrease in calcified bone area may be prevented by treatment with either 1,25-(OH)2D3 or 24,25-(OH)2D3.
Withdrawal of salt supplementation from adrenalectomized Wistar rats distinguishes between those animals with, and those without, adrenocortical insufficiency
Authors: Gardiner S. M. , Bennett T. , MacDonald I. A.
Published: August 2015

1. The effects of replacing a 1% NaCl drinking solution with Na+-free water for 2 days on body weight and fluid and electrolyte balances were studied in adrenalectomized and sham-operated rats.

2. Eight weeks after operation, after the animals had been drinking Na+-free water for 2 days, some adrenalectomized animals (about 75%; designated group 1) experienced body weight losses which were outside the 99% confidence limits for the sham-operated rats (– 9.2 to + 5.3 g) whereas the remainder (designated group 2) were indistinguishable from the controls.

3. The body weight loss in group 1 was associated with negative fluid, Na+ and K+ balances. In group 2 rats, fluid balance was maintained as well as in the sham-operated rats, but their handling of Na+ and K+ was different.

4. In a separate experiment, plasma aldosterone, corticosterone, catecholamine and solute concentrations were measured in adrenalectomized rats from groups 1 and 2 (selected on the basis of body weight loss whilst drinking Na+-free water) and sham-operated rats, after drinking Na+-free water for 2 days.

5. In group 1 animals, plasma aldosterone levels were unmeasurable and corticosterone was extremely low (less than 5% of controls). In group 2, aldosterone was measurable but low, and corticosterone was higher than in group 1 but lower than in sham-operated rats. In line with these findings, animals in group 1, but not those in group 2, were hyponatraemic and hyperkalemia These results are consistent with the activation of latent adrenocortical tissue in the group 2 animals.

6. We suggest that monitoring body weight changes resulting from drinking Na+-free water for 2 days provides a useful, non-invasive test for reliably distinguishing between those adrenalectomized animals with and those without adrenocortical insufficiency.
Effect of albumin on taurocholate uptake kinetics in rat liver
Authors: Aldini Rita , Roda Aldo , Morselli-Labate Antonio Maria , Simoni Patrizia , Roda Enrico , Barbara Luigi
Published: August 2015

1. Isolated rat livers were perfused in a single pass with increasing doses of taurocholate with and without albumin in the perfusion media.

2. The kinetics of taurocholate uptake were thus evaluated.

3. In all the experiments, taurocholate uptake showed Michaelis-Menten kinetics. Increasing the albumin concentration in the medium resulted in an increase in the Km, without effect on the Vmax. When taurocholate and albumin were kept constant (20:1 molar ratio), the Vmax was significantly lower than in the other experiments.

4. These data suggest that taurocholate uptake shows saturation in the absence of albumin and that albumin reduces taurocholate uptake.
An assessment of the sources of dietary salt in a British population
Authors: Sanchez-Castillo C. P. , Warrender S. , Whitehead T. P. , James W. P. T.
Published: August 2015

1. An epidemiological study was conducted in the market town of March, Cambridgeshire, to assess the quantitative importance of cooking and table salt to total dietary salt intake by the use of a fused mixture of lithium carbonate and sodium chloride.

2. Men and women aged 20–60 participated in a 12 day study with sequential 24 h urine collections to assess salt sources over a 7 day period.

3. Total salt consumption estimated from urinary chloride excretion amounted to 10.6 ± 0.55 (sem) g in 33 men and 7.4 ± 0.29 (sem) g in 50 women. The cooking salt eaten was only 0.45 ± 0.09 (sem) g in men and women, with men eating more table salt (0.77 g/day) than women (0.46 g/day).

4. Discretionary sources, i.e. cooking and table salt use, contributed only 15% to the total intake. Salt from manufacturing foods and catering in purchased food therefore provided on average 85% of total salt intake. These results are consistent even when an allowance is made for the slightly poorer pouring quality of the lithium-tagged salt.

5. The importance of food as a source of salt was reflected in the significant relationship between the weight of the individual and the amount of salt eaten (for males P < 0.05 and for females P < 0.001).

6. Cooking salt consumption did not relate to the amount of salt derived from purchased food nor did table salt use relate to the amount of salt in cooked foods.

7. Husbands and wives showed a high correlation in their salt use but the husbands had higher intakes of salt from purchased food and from cooking salt. They also used more table salt than their wives.
Ion flux and Na+,K+-ATPase activity of erythrocytes and leucocytes in thyroid disease
Authors: Khan F. A. , Baron D. N.
Published: August 2015

1. In hyperthyroidism, erythrocytes show decreased Na+,K+-ATPase activity, decreased [3H]ouabain binding capacity (an index of the number of sodium pumps) and decreased active sodium and potassium flux rates, with a high intracellular sodium concentration.

2. As erythrocytes are non-nucleated and atypical cells, we have studied electrolyte status in thyroid disease using mixed leucocytes as well; the results obtained differed from those in erythrocytes.

3. When compared with findings in healthy subjects, leucocyte Na+,K+-ATPase activity, [3H]-oubain binding capacity, total and active rubidium (used instead of potassium) influx were all significantly increased in untreated hyperthyroidism and decreased in untreated hypothyroidism.

4. In hyperthyroidism, there was also a decrease in plasma potassium, an increase in sodium efflux rate and efflux rate constant, but no significant changes in cell sodium and potassium concentrations. All these changes returned to normal in successfully treated patients. There was a significant correlation between these abnormalities of electrolyte status and thyroid disease status (as serum thyroid stimulating hormone and free thyroxine).
Duodenal and ileal lipid suppresses postprandial blood glucose and insulin responses in man: Possible implications for the dietary management of diabetes mellitus
Authors: Welch I. McL. , Bruce C. , Hill S. E. , Read N. W.
Published: August 2015

1. Infusion of lipid into the ileum delays the transit of a meal through the stomach and small intestine and could therefore influence the rate and degree of nutrient absorption.

2. Experiments were carried out on human volunteers to investigate the effect of infusion of lipid into either the duodenum or ileum on blood glucose, insulin and gastric emptying after ingestion of a mashed potato meal.

3. Infusions of lipid into either the duodenum or the ileum significantly reduced or abolished the immediate postprandial rises in blood glucose and insulin and significantly delayed gastric emptying. Blood glucose and insulin rose shortly after the lipid infusion terminated.

4. Addition of corn oil to a meal of mashed potato also reduced blood glucose and insulin and delayed gastric emptying.

5. Intestinal lipid can thus modify the glycaemic and insulinaemic responses to a meal, and this modulation probably explains the reduced metabolic responses to a meal containing fat compared with a fat free meal. This principle could be of value in the dietary control of diabetes mellitus.
The role of the autonomic nervous system in the resting tachycardia of human hyperthyroidism
Authors: Maciel Benedito C. , Gallo Lourenco , Neto José A. Marin , Maciel Léa M. Z. , Alves Maria L. D. , Paccola Glória M. F. , Iazigi Nassim
Published: August 2015

1. The mechanisms that control resting heart rate in hyperthyroidism were evaluated in six patients before and after treatment with propylthiouracil.

2. The patients were subjected to pharmacological blockade under resting conditions in two experimental sessions: first session, propranolol (0.2 mg/kg body weight); second session, atropine (0.04 mg/kg body weight) followed by propranolol (0.2 mg/kg body weight). All drugs were administered intravenously.

3. Resting heart rate was significantly reduced from 100 ± 6.5 beats/min to 72 ± 2.5 beats/min (P < 0.005) after clinical and laboratory control of the disease. After double blockade, intrinsic heart rate was reduced from 105 ± 6.8 beats/min before treatment to 98 ± 6.0 beats/min after treatment (P < 0.025). The reduction in heart rate caused by propranolol was not significantly different before (−13 ± 1.4 beats/min) and after (−9 ± 1.0 beats/min) propylthiouracil. In contrast, atropine induced a higher elevation of heart rate after treatment (45 ± 8.6 beats/min) than before treatment (26 ± 4.0 beats/min).

4. The present results suggest no appreciable participation of the sympathetic component of the autonomic nervous system in the tachycardia of hyperthyroidism, at least under the conditions of the present study. The small change observed in intrinsic heart rate, although significant, seems to indicate that this is not the most important mechanism involved in this tachycardia.

5. Our results suggest that an important reduction in the efferent activity of the parasympathetic component participates in the mechanisms that modify resting heart rate in hyperthyroidism.
Hypoxic pulmonary vasoconstriction persists in the human transplanted lung
Authors: Robin Eugene D. , Theodore James , Burke Conor M. , Oesterle Stephen N. , Fowler Michael B. , Jamieson Stuart W. , Baldwin John C. , Morris Adrian J. , Hunt Sharon A. , Vankessel Antonius , Stinson Edward B. , Shumway Norman E.
Published: August 2015

1. The preservation of hypoxic pulmonary vasoconstriction (HPV) in the denervated lung was studied in five human heart–lung transplant recipients.

2. AH five patients showed significant increases in mean pulmonary artery pressure and pulmonary vascular resistance during hypoxic exposure, returning toward normoxic values during recovery. Aside from Pao2 and Pao2, other factors known to influence pulmonary vascular resistance did not change significantly during the hypoxic period.

3. There was no relation between the length of the post-transplantation period and the intensity of HPV, suggesting that reinnervation of the pulmonary vascular bed did not account for persistent HPV and that HPV persists in the human transplanted lung despite the loss of autonomic neural innervation.
Circulatory response to postural change in healthy male subjects in relation to age
Authors: Dambrink J. H. A. , Wieling W.
Published: August 2015

1. The initial heart rate (HR) response evoked by standing up and 70° head-up tilt from the supine resting position, as well as the changes in HR and blood pressure after 1–2 min in the upright position, was analysed in teenage boys (aged 10–15 years) and healthy old men (aged 60–90 years).

2. Standing up induced a characteristic temporary HR increase that lasted 20 s and far exceeded the gradual initial HR rise induced by head-up tilt. The main effect of age on the initial HR transients was a definite diminution of the response.

3. After 1–2 min standing and tilting, young subjects showed a pronounced increase in HR and diastolic pressure with little change in systolic pressure. In contrast, old subjects showed a lesser increase in HR and diastolic pressure and a decrease in systolic pressure. A fall in systolic pressure of greater than 20 mmHg after 1 min of active standing was, however, not observed.

4. It is concluded that the circulatory adjustment to the stress of postural change differs markedly between young and elderly subjects. In healthy old subjects marked postural hypotension appears to be rare.
Lung lavage fluid from patients with α1-proteinase inhibitor deficiency or chronic obstructive bronchitis: anti-elastase function and cell profile
Authors: Morrison Heather M. , Kramps Johannes A. , Burnett David , Stockley R. A.
Published: August 2015

1. The anti-elastase composition of bronchoalveolar lavage (BAL) fluid from (α1-proteinase inhibitor (α1PI) deficient and bronchitic patients was determined by immunological and functional assays, together with the cell profile of the BAL fluid.

2. α1PI, anti-leucoprotease and α2-macroglobuin were present in all the samples. BAL fluid α1PI concentrations were significantly lower in the group with serum α1PI deficiency.

3. Lavage fluid from α1PI deficient subjects inhibited less porcine pancreatic elastase than bronchitic BAL fluid (P < 0.005). However, the α1PI was only about 50% active as an inhibitor in both groups.

4. There was no difference in the amount of neutrophil elastase (NE) inhibited per ml of lavage fluid or per mol of the measured inhibitors in the secretions, but both groups inhibited more enzyme than would be expected for these inhibitors (α1PI deficient: median 4.78 mol of NE/mol of known inhibitors, range 0.88–78.80; bronchitic: 1.14, 0.21–4.66), suggesting that an additional inhibitor is present.

5. The total leucocyte and neutrophil counts were elevated (2P < 0.01) in the lavages of α1PI deficient patients, suggesting a greater potential elastase burden than subjects with normal α1PI.
Glucose absorption from maltotriose and glucose oligomers in the human jejunum
Authors: Jones B. J. M. , Higgins B. E. , Silk D. B. A.
Published: August 2015

1. The jejunal absorption of glucose from (1–4)-linked glucose oligomers including maltotriose has been compared with that from free glucose and sucrose in normal subjects.

2. A steady-state perfusion technique in vivo was used to study proximal jejunal assimilation of isotonic sugar-saline solutions isocaloric with 140 mmol/l glucose. Endogenous α-amylase was excluded from the test segment by proximal balloon occlusion. The glucose oligomer mixture consisted mainly of maltotriose, maltotetraose, maltopentaose and maltoheptaose.

3. Glucose absorption was significantly faster from maltotriose alone and from the glucose oligomer mixture than from 140 mmol/l glucose controls, whereas glucose absorption from 70 mmol/l sucrose was similar to that from 70 mmol/l glucose plus 70 mmol/l fructose.

4. Hydrolysis in vivo of maltotriose, the oligomer mixture and sucrose were similar, indicating that capture of glucose released by brush border sucrose hydrolysis was less efficient than that associated with (1–4)-linked oligomer hydrolysis. This suggests that the stoichiometric relationship of the active hydrolysis sites for sucrose to the glucose transport system is less advantageous than that of active sites for maltose hydrolysis.

5. Hydrolysis of oligomers larger than maltohexaose may be rate limiting for glucose absorption in the absence of luminal amylase activity.
Assessment of beat to beat changes in cardiac output during the Valsalva manoeuvre using electrical bioimpedance cardiography
Authors: Smith Stephen A. , Salih Mahmood M. , Littler William A.
Published: August 2015

1. Beat to beat changes in cardiac output during standardized Valsalva's manoeuvres were recorded using electrical bioimpedance cardiography in 13 normal subjects.

2. Cardiac output increased by 12 ± 5% after 1 s of straining solely because of an increase in heart rate. Subsequently, cardiac stroke volume and cardiac output fell during the strain to lows of − 40 ± 6% and − 21 ± 3% respectively at 15 s.

3. There was a sustained increased in cardiac output (maximum + 17 ± 4%) in the late post strain period.

4. The mean coefficient of variation in impedance measurements of cardiac output was 6.8% during all parts of Valsalva's manoeuvre, with no single value exceeding 10%.
Effect of thyroparathyroidectomy on the activities of thymidylate synthetase and thymidine kinase during liver regeneration after partial hepatectomy
Authors: Nakata Rieko , Tsukamoto Ikuyo , Miyoshi Masamitsu , Kojo Shosuke
Published: August 2015

1. Thyroparathyroidectomy (TPTX) carried out at 72 h before partial hepatectomy (PH) reduced the induction of hepatic thymidylate synthetase (TS) and thymidine kinase (TK), which are rate-determining enzymes in DNA synthesis, at 24 h after PH.

2. When TPTX was carried out at 24 h before PH, TK activity at 24 h after PH was not reduced at all, yet TS activity was reduced significantly. Thus the effect of TPTX differed in time dependence between TS and TK.

3. The depression of TK activity in rats which were subjected to TPTX at 72 h before PH, was recovered by Ca2+ supplementation. This result demonstrated that the rise of TK activity in regenerating liver is regulated by plasma Ca2+.

4. Since a high dose of tri-iodothyronine (T3) was required to cause elevation of the activities of these enzymes and DNA content in 24 h-regenerating liver of TPTX rats, the relative contribution of T3 to liver regeneration may be small.
Is there neural control over electrolyte reabsorption in the human salivary gland?
Authors: Levin S. L. , Khaikina L. I.
Published: August 2015

1. A study was made of changes induced by cholinergic agonists and antagonists in the K+, Na+, Ca2+ and Cl− content of saliva of 22 human subjects with denervated parotid salivary glands.

2. At all stages after denervation there was an increased content of Na+ and Cl− in the secretion of the denervated gland as compared with that of the control glands: (a) after administration of pilocarpine and carbacholine; (b) after administration of a combination of atropine and pilocarpine; (c) in ‘paradoxical’ salivation induced by atropine, scopolamine, metacine or chlorosyle; (d) in spontaneous secretion; (e) in reflex secretion when this was partially restored.

3. The concentrations of Na+ and Cl− in the secretion of the denervated gland were disproportionately higher than would have been expected from the raised salivation rate.

4. Secretions from the denervated glands by virtue of their increased content of Na+ and Cl− resembled so-called primary saliva.

5. The increased output of Na+ and Cl− and high concentrations of these ions in the secondary saliva after denervation indicates that there is loss of the normal neural control over reabsorption of electrolytes in the epithelium of the glandular ducts. Further, that absence of this control results in disturbances of membrane ionic transport, of membrane permeability and of the metabolism of the gland.