bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effects of Oral Almitrine on Pattern of Breathing and Gas Exchange in Patients with Chronic Obstructive Pulmonary Disease
Authors: Stradling J. R. , Nicholl C. G. , Cover D. , Davies E. E. , Hughes J. M. B. , Pride N. B. 
Published: August 2015

1. Almitrine at a low dose of 100 mg orally significantly raises Pao2 and lowers Paco2 in patients with chronic obstructive pulmonary disease, compared with placebo, when they were breathing air or 28% oxygen.
2. The estimated ideal alveolar — arterial Po2 difference was less after almitrine compared with placebo, when patients were breathing either air or 28% oxygen.
3. After almitrine overall ventilation breathing air increased by 10% but this did not reach statistical significance. During 28% oxygen breathing almitrine hardly altered overall ventilation but the inspiratory duty cycle (Ti/Ttot.) decreased and mean inspiratory flow rate (VT/Ti) increased compared with placebo. These changes were significant on a paired t-test (P&lt;0.05).
4. Changes in both volume and pattern of breathing may explain the improved gas exchange in the lung after almitrine.
The Importance of Conjugation in Biliary Secretion of Ursodeoxycholate and 7-Ketolithocholate in the Rat
Authors: Erlinger S. , Dumont M. , Zouboulis-Vafiadis I. , De Couet G. 
Published: August 2015

1. The biliary maximum secretory rate (SRmax.) of glycoursodeoxycholate in the bile fistula anaesthetized rat was about five times that of unconjugated ursodeoxycholate.
2. Likewise, the biliary SRmax. of tauro-7-ketolithocholate was more than three times that of unconjugated 7-ketolithocholate. The SRmax. of 7-ketolithocholate infused with taurine (to avoid depletion of the taurine pool) was still significantly lower than that of exogenous tauro-7-ketolithocholate.
3. These data support the hypothesis that, for bile acids that are poorly water soluble, the maximal biliary secretion rate is dependent on conjugating capacity, which is the limiting step in the overall transport from plasma into bile.
Lipid peroxidation in rheumatoid arthritis: Thiobarbituric acid-reactive material and catalytic iron salts in synovial fluid from rheumatoid patients
Authors: Rowley David , Gutteridge John M. C. , Blake David , Farrs Margaret , Halliwell Barry 
Published: August 2015

1. Thiobarbituric acid (TBA)-reactive material is present in serum and knee joint synovial fluid from rheumatoid patients, consistent with lipid peroxidation occurring in vivo.
2. The amount of TBA-reactive material in synovial fluid correlates with the concentration of iron salts present as determined by the bleomycin method, presumably because iron is an important catalyst of radical reactions in vivo.
3. There appear to be significant correlations between the contents of TBA-reactive material and bleomycindetectable iron in synovial fluid and the activity of rheumatoid arthritis as assessed with a clinical index of local inflammation and with various laboratory parameters.
Oophorectomy leads to a selective decrease in 1,25-dihydroxycholecalciferol receptors in rat jejunal villous cells
Authors: Chan S. D. H. , Chiu D. K. H. , Atkins D. 
Published: August 2015

1. The distribution of 1,25-dihydroxychole-calciferol [1,25-(OH)2D3] receptors in isolated rat jejunal cells was investigated in normal and oophorectomized female rats and also in vitamin D-deficient animals.
2. Oophorectomy caused a selective reduction in 1,25-(OH)2D3 receptor numbers in villous cells, the reduction being similar (37%) in both normal and vitamin D-deficient animals.
3. The data suggest that this effect of oophorectomy reflects a direct effect of oestrogens in the intestinal synthesis of 1,25-(OH)2D3 receptors, independent of the renal synthesis of 1,25-(OH)2D3.
4. It is proposed that this phenomenon may, in part, explain the reduction in calcium absorption which occurs after oophorectomy or the menopause.
Vascular Hypersensitivity to Noradrenaline: A Possible Mechanism of Hypertension in Rats with Chronic Uraemia
Authors: Zimlichman R. R. , Chaimovitz C. , Chaichenco Y. , Goligorsky M. , Rapoport J. , Kaplanski J. 
Published: August 2015

1. Studies were performed to evaluate the mechanism involved in the hypertension of moderate renal failure in partially (five-sixths) nephrectomized rats. Cardiac index (CI) was studied by means of the microsphere technique, and systemic vascular resistance (SVR) calculated from the mean arterial resistance MAP/CI, in four groups of experimental animals: (A) partially nephrectomized rats; (B) group A rats chronically treated with the calcium channel blocker verapamil; (C) sham-operated rats; (D) sham-operated rats treated with verapamil.
2. The results demonstrate a significant increase in MAP in group A rats, which was due to a 72% increase in SVR as compared with groups C and D. In group B rats, MAP decreased significantly owing to a marked decrease in SVR (40%) as compared with group A. However, MAP remained higher in group B than in group C.
3. The vascular responsiveness to noradrenaline was studied in group A, group C and group A rats after parathyroidectomy (group A1). An increased pressor responsiveness to noradrenaline was indicated by a shift of the noradrenaline dose-response curve to the left in group A rats as compared with group C rats. This change was corrected after partial nephrectomy.
4. We conclude that hypertension in nephrectomized rats is due to an increase in SVR, and that an increased pressor responsiveness to catecholamines may play a role in this phenomenon. Furthermore, verapamil reduced the hypertension, and parathyroidectomy improved the abnormal sensitivity to noradrenaline in group A rats.
5. These results raise the possibility that an abnormality in calcium metabolism, possibly due to secondary hyperparathyroidism, may be implicated in the hypertension of mildly uraemic rats.
Mechanisms of Initial Blood Pressure Response to Postural Change
Authors: Borst C. , Van Brederode J. F. M. , Wieling W. , Van Montfrans G. A. , Dunning A. J. 
Published: August 2015

1. The influence of supine rest on the blood pressure response to standing and 70° head-up tilt was studied in detail for the first 30 s after the change of posture.
2. Following 20 min of supine rest, the active transition to standing was accompanied by an immediate increase in systolic pressure of 29 ± 6 mmHg (mean ± sem). This was followed by large fluctuations in systolic pressure: to −28 ± 2 mmHg below control after 7 s and to 22 ± 2 mmHg above control after 22 s (17 mmHg in excess of the systolic pressure level after head-up tilt).
3. Following 1 min of supine rest, there was no difference in the immediate increase in systolic pressure. However, the magnitude of the subsequent changes was significantly diminished.
4. With head-up tilt the immediate increase in blood pressure was absent and afterwards small changes were found that were also significantly influenced by the period of prior rest.
5. Taken in conjunction with earlier studies, the following mechanisms are suggested. The immediate blood pressure increase resulted from compression of arteries by the contracting postural muscles. The subsequent blood pressure fall was caused by at least two mechanisms: (a) the fall was predominantly of reflex origin, because the immediate pressure increase stimulated the systemic baroreceptors; (b) supine rest possibly augmented the translocation of blood from the thorax which contributed, approx. 5 s from standing, to the reflex fall of blood pressure.
Sex Differences in the Metabolism of Ethanol and Acetaldehyde in Normal Subjects
Authors: Arthur M. J. P. , Lee A. , Wright R. 
Published: August 2015

1. Blood ethanol and acetaldehyde concentrations were compared in normal young male and female subjects after intravenous infusion of 0.5 g of ethanol/kg body weight.
2. After the infusion was completed, females had significantly higher mean concentrations of blood ethanol than males, but a significantly lower apparent volume of distribution (Vd) of ethanol (0.56 ± 0.06 l/kg vs 0.68 ± 0.17 l/kg, P&lt;0.05). There were no differences in ethanol elimination rate (EER) (females 1.78 ± 0.3 mmol h−1 kg−1; males 1.87 ± 0.41 mmol h−1 kg−1). The mean value of the areas under the acetaldehyde/time curves (AUC) were significantly greater for males (88.5 ± 26.4 μmol/l. h) than for females (58.6 ± 31.5 μmol/l. h, P&lt;0.05).
3. Since the ethanol elimination rate was similar in both sexes, the observed differences in AUC for acetaldehyde may reflect the sex differences in metabolism of this substrate by the liver.
Circadian Rhythms of Serum Thyrotrophin and Body Temperature in Euthyroid Individuals and their Responses to Warming
Authors: O'malley B. P. , Richardson A. , Cook N. , Swart S. , Rosenthal F. D. 
Published: August 2015

1. The diurnal rhythms of body temperature and serum thyrotrophin (TSH) levels in euthyroid individuals behaved inversely to one another.
2. An artificially induced rise in the body temperature of these individuals was accompanied by a fall in serum thyrotrophin levels, the amplitudes of their respective rhythms decreasing simultaneously.
3. There was a marked correlation between the degrees of change in body temperature and circulating thyrotrophin levels respectively during warming.
4. In normal subjects manipulation of the diurnal rhythm of body temperature brings about inverse alterations in the thyrotrophin rhythm.
Serum Alkaline Phosphodiesterase I in Experimental Biliary Obstruction in the Rat
Authors: Simpson Stuart R. , Rahman K. , Billington D. 
Published: August 2015

1. Alkaline phosphodiesterase I was present in rat liver at approx. 100-fold greater activity than alkaline phosphatase, and in rat bile at approx. 25-fold greater activity.
2. Rat serum alkaline phosphodiesterase I was increased 6-fold whilst serum alkaline phosphatase was increased only 2-fold 96 h after bile duct ligation.
3. In contrast to alkaline phosphatase, hepatic alkaline phosphodiesterase I was not affected by bile duct ligation, suggesting its raised serum activity was due to bile regurgitation rather than overspill of the enzyme from liver into blood.
4. Gel filtration showed that 8 and 96 h after bile duct ligation the serum contained a high molecular weight form of alkaline phosphodiesterase I.
5. It is suggested that alkaline phosphodiesterase I offers a potentially useful indicator of biliary obstruction in the rat.
Platelet volume subpopulations in acute myocardial infarction: an investigation of their homogeneity for smoking, infarct size and site
Authors: Kishk Y. T. , Trowbridge E. A. , Martin J. F. 
Published: August 2015

1. Mean platelet volume and count were measured in three groups: patients with acute myocardial infarction, a control group with myocardial ischaemia but no infarction and an asymptomatic group of young males.
2. Mean platelet volume was significantly larger in the myocardial infarction group compared with the ischaemic heart disease group or the asymptomatic group.
3. Two subpopulations were present within the myocardial infarction group. One subgroup had a large mean platelet volume and low count. The other subpopulation was indistinguishable, with regard to platelet count and mean volume, from the ischaemic heart disease group.
4. Over 60% of the myocardial infarction group lay in the area of high platelet volume and low count compared with 13% of the ischaemic heart disease control group and 38% of the asymptomatic group. Acute myocardial infarction is likely to be associated with a large mean platelet volume and low count compared with the ischaemic heart disease group. There is no statistical evidence that this condition is related to smoking or size and site of infarct.
5. This evidence suggests that large mean platelet volume and low platelet count could be a major risk factor for myocardial infarction.
Cathepsin B-like cysteine proteinase activity in sputum and bronchoalveolar lavage samples: relationship to inflammatory cells and effects of corticosteroids and antibiotic treatment
Authors: Burnett David , Stockley Robert A. 
Published: August 2015

1. Cathepsin B-like activity was measured in lung secretions by using the fluorimetric substrate benzyloxycarbonyl-l-arginine-l-arginine-4-methyl-7-coumarylamide (Z-Arg-Arg-MEC). The enzyme had a pH optimum of approximately 5.5 and had the characteristics of an alkaline-stable cysteine proteinase.
2. Enzyme activity in the sputum from ten subjects with chronic bronchitis was significantly reduced after 5 days’ treatment with prednisolone.
3. Seven patients with bronchiectasis were studied before and after 14 days’ treatment with amoxycillin. Cysteine proteinase activity was significantly reduced after 7 days’ therapy, in parallel with a change in sputum quality from purulent to mucoid. One week after cessation of treatment enzyme levels were again increased but were still significantly lower than pretreatment values.
4. Enzyme activity in 21 bronchoalveolar lavage specimens correlated significantly with neutrophil counts but not with macrophage counts.
5. Cysteine proteinase activity in lung secretions resembles that of cathepsin B but is alkaline-stable, suggesting it is a distinct enzyme. The levels of cysteine proteinase in lung secretions appear to be related to the presence of inflammation or infection.
Effects of glucose and d-3-hydroxybutyrate on human pancreatic islet cell function
Authors: Rhodes C. J. , Campbell I. L. , Szopa T. M. , Biden T. J. , Reynolds P. D. , Fernando O. N. , Taylor K. W. 
Published: August 2015

1. β-Cell function in human islets derived from a number of kidney donors was investigated by using various types of islet preparations.
2. With fresh islets, both insulin release and biosynthesis were increased by raising glucose concentrations, although the response was a variable one.
3. In fresh islets, the effects of 5 mmol of glucose/l on release were potentiated by 10 mmol of d-3-hydroxybutyrate/l.
4. Insulin release at 20 mmol of glucose/l was inhibited by adrenaline (0.1 mmol/l), and potentiated by theophylline (10 mmol/l) in the presence of 5 mmol of glucose/l, in islets cultured for 4 days.
5. After culture for 8 days, islets still showed an increase in insulin release and biosynthesis in response to glucose.
6. Pancreas slices derived from fresh human tissue also responded to increasing concentrations of glucose with a sigmoidal curve for insulin release.
Cholesterol gallstone pathogenesis: a study of potential nucleating agents for cholesterol crystal formation in bile
Authors: Whiting M. J. , Watts J. McK. 
Published: August 2015

1. Cholesterol monohydrate crystal formation was measured quantitatively in model bile solutions, which were supersaturated with cholesterol, by a radiochemical method and qualitatively in human gallbladder bile by polarizing microscopy.
2. Various agents, which have been postulated to act as nucleating factors for cholesterol crystal and gallstone formation, were added to bile and their effect on the appearance of cholesterol crystals was determined. These agents included calcium salts found in gallstones (calcite, aragonite, apatite, bilirubinate), Escherichia coli bacteria, pigment residues from cholesterol gallstones, bilirubin and several mucin preparations.
3. Human gallbladder bile, which was collected from patients with and without cholesterol gallstones, was also mixed with model bile to examine whether nucleating or anti-nucleating factors were present.
4. None of the agents tested markedly and consistently promoted cholesterol monohydrate crystal formation in model or human bile, except seed crystals of cholesterol monohydrate which were used as a control. Human gallbladder bile from obese patients without gallstones delayed the appearance of cholesterol crystals in model bile solutions, whereas gallbladder bile from gallstone patients did not.
5. These results do not provide experimental support for the hypothesis that calcium salts and pigment material found in gallstones, or gallbladder mucin at concentrations less than 10 mg/ml, act as nucleating agents for cholesterol crystal and stone formation. The difference between gallbladder biles from patients with and without gallstones in their propensity to form cholesterol crystals may be due to the presence of an anti-nucleating factor in normal bile.
Relative agonist potency as a means of differentiating α-adrenoceptors and α-adrenergic mechanisms
Authors: Ruffolo Robert R. 
Published: August 2015

1. Relative potencies (ED50), affinities (assessed as dissociation constants) and efficacies (i.e. ability to activate the receptor) of agonists are useful in subclassifying and differentiating α-adrenoceptors.
2. The postsynaptic α-adrenoceptor of rat aorta is of the α1-subtype, but may differ from the α1-adrenoceptor of rabbit and guinea pig aortae, based on comparison of relative potencies of selected agonists.
3. By evaluating the relative potency of agonists, qualitative and quantitative species differences between α1-adrenoceptors in rat and guinea pig are observed in a variety of test systems in vivo and in vitro.
4. By comparing the relative potencies of aromatic hydroxyl-substituted phenethylamines and imidazolines at α1-adrenoceptors in guinea pig aorta, differences in the ability of these two classes of α-adrenoceptor agonists to bind to, and subsequently activate, α1-adrenoceptors have been observed.
5. Evaluating the relative potencies of agonists, when used in conjunction with other techniques, provides a valuable method for classifying α-adrenoceptors and for studying α-adrenergic mechanisms.
Ageing and α-adrenoceptors
Authors: Docherty J. R. , O'Malley K. 
Published: August 2015

1. Ageing changes in α-adrenoceptors can be summarized as follows: except in the eye, where there is an apparent increased responsiveness with increasing age in man, peripheral α-adrenoceptor responsiveness has generally been found to be either unchanged or reduced with increasing age in animals and man.
2. Even where changes have been found it remains to be clarified whether these changes are selective changes in α-receptors or whether they are due to alterations in responsiveness beyond the level of the receptor.
The adrenaline -α2-adrenoceptor-mediated vasoconstrictor axis
Authors: Bolli Peter , Erne Paul , Kiowski Wolfgang , Amman Franz W. , Bühler Fritz R. 
Published: August 2015

1. In patients with essential hypertension plasma adrenaline concentrations have been found to be higher than in normotensive subjects and this may represent increased adrenergic activity. Adrenaline released into the circulation can be taken up by the sympathetic nerve ending and as it is re-released as a co-transmitter it enhances exocytotic noradrenaline release by stimulating prejunctional β-adrenoceptors and as a consequence it contributes to postjunctional α1-adrenoceptor-induced vasoconstriction. Adrenaline may also induce vasoconstriction via post- and extra-junctional (α2-adrenoceptors, as shown by a decrease in the forearm blood flow during adrenaline infusions in the postjunctional α1- and β-blocked forearm vasculature, an effect that could be antagonized by α2-adrenoceptor blockade with yohimbine.
2. α2-Adrenoceptor stimulation in platelets showed an increased sensitivity to adrenaline, as determined by sensitivity in counteracting the inhibitor effect of PGI2 on intracellular free calcium concentration in untreated patients with essential hypertension, when compared with treated patients or normotensive subjects. As these effects can be normalized by antihypertensive treatment this suggests that the increased hormone sensitivity may be related to the elevated intracellular free calcium concentration.
3. Thus adrenaline, via pre- and post-junctional adrenoceptors, may contribute to enhanced vascular smooth muscle contraction, which most likely is sensitized by the elevated intracellular calcium concentration.
Renal adaptation and gut hormone release during sodium restriction in ileostomized man
Authors: Unwin R. J. , Moss S. , Peart W. S. , Wadsworth Jane 
Published: August 2015

1. The renal excretion of water, electrolytes, aldosterone and kallikrein was monitored in 12 ileostomized patients before and during sodium deprivation. Changes in plasma renin activity (PRA), plasma aldosterone and plasma arginine vasopressin (AVP) concentrations were measured, together with aldosterone in ileal fluid. The pattern of gut peptide release in response to a test meal was also examined to assess whether a circulating gut peptide might be involved in the renal adaptation to sodium restriction, and compared with healthy normal subjects who were under no dietary constraint.
2. In each patient renal sodium excretion fell within 8–12 h of sodium deprivation and was associated with a prompt and significant rise in PRA; much later increases in plasma aldosterone concentration and renal aldosterone excretion occurred, and were established by day 2 of sodium restriction. No consistent change in renal kallikrein excretion was found.
3. Ileal sodium loss was little changed by sodium deprivation, but ileal potassium concentration rose steadily and became significantly correlated with PRA, and to a lesser extent with renal aldosterone excretion.
4. Of the gut peptides measured in plasma, only the insulin profile was altered by sodium deprivation, with an increase in the test meal response; insulin has previously been shown to have a significant antinatriuretic action at physiological concentrations. Plasma levels of pancreatic polypeptide and motilin were increased in ileostomized patients when compared with normal subjects, but were unaffected by the change to a low sodium diet.
5. An early increase in urine flow and water diuresis occurred during sodium deprivation, following a cyclical pattern with peaks each evening. There were no corresponding changes in measured plasma AVP concentration or creatinine clearance. This observation remains unexplained.
Serum immunoreactive erythropoietin in hypoxic lung disease with and without polycythaemia
Authors: Wedzicha J. A. , Cotes P. Mary , Empey D. W. , Newland A. C. , Royston J. P. , Tam R. C. 
Published: August 2015

1. We studied 20 patients with chronic airflow obstruction, 10 patients without polycythaemia and 10 patients with compensatory polycythaemia having respectively mean red cell mass 24.7 (sd 4.2) and 47.8 (sd 7.5) ml/kg, mean daytime Pao2 7.6 and 6.9 kPa, mean FEV, 0.85 and 0.82 1. Groups were matched for severity of daytime arterial hypoxaemia but nocturnal arterial oxygen desaturation was more severe in the patients with polycythaemia than in those without. We also studied six additional patients with chronic airflow obstruction and polycythaemia and 19 normal controls.
2. Estimates of serum immunoreactive erythropoietin (siEp) in those without polycythaemia were 19 m-i.u./ml (geometric mean) with 95% confidence range 11–35 m-i.u./ml and stable during 3 months. In those with polycythaemia they were similar and consistent in five and, in the other five, higher on at least one occasion. There was no significant difference between siEp in daytime (12.00 hours to 16.00 hours) and morning (07.00 hours) samples but geometric mean estimates of erythropoietin in paired daytime and morning samples were higher and more variable in patients with polycythaemia than in those without. The geometric mean estimate of siEp in all patients with chronic airflow obstruction and polycythaemia was greater than in normal subjects but, despite secondary polycythaemia, siEp could be in the range for normal subjects.
3. In the patients with polycythaemia we were unable to predict the finding of normal or elevated siEp.
4. Changes in siEp after erythrapheresis (10–26% reduction in packed cell volume) were observed in the 10 patients with polycythaemia and in one without. One month after erythrapheresis, packed cell volume remained below and siEp was above initial pretreatment levels, implying an erythropoietin secretory response and that the development of secondary polycythaemia had induced a fall in siEp.