bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aortic compliance measured by non-invasive Doppler ultrasound: Description of a method and its reproducibility
Authors: Wright J. S. , Cruickshank J. K. , Kontis S. , Doré Caroline , Gosling R. G. 
Published: August 2015

1. Aortic compliance (expressed as percentage increase in lumen diameter for a pulse pressure of 10 mmHg) was calculated from the characteristic pulse wave velocity deduced from ‘foot to foot’ transit times of the blood flow pulse over a measured length of aorta. Two continuous wave Doppler ultrasound transducers were used: one insonating the root of the left subclavian artery, the other the abdominal aorta proximal to its bifurcation. Measurements were made after the subject had been supine for 5 min to achieve stable conditions.
2. Transit times were calculated on-line in real-time from the delay between the start of the systolic upstroke in the flow velocity sonograms recorded by the two transducers.
3. Within-visit variation was minimized by measuring over 45 cardiac cycles repeated three separate times and calculating an overall mean value for aortic compliance. A full measurement took 5–10 min.
4. Reproducibility of this overall mean value of aortic compliance was assessed at 1 month in 30 subjects (aged 60 ± 7 years, mean ± sd) and at 3 months in 23 different subjects (59 ± 8 years). Aortic compliance values ranged from 0.1 to 2.0%/10 mmHg (see eqn 4).
5. The mean paired difference between aortic compliance values was −0.02 between 0 and 1 month, and 0.03 between 0 and 3 months, with respective 95% confidence limits of −0.06 to 0.03 and −0.03 to 0.09 embracing zero, thus not differing significantly from baseline.
6. Aortic compliance can be both simply and reproducibly measured non-invasively; if an individual was measured on two occasions, then 95% of the time the difference between the two measurements of aortic compliance would be &lt;0.28 (twice the sd of the 3 month differences).
Patients' Perception of Distress Due to Symptoms and Effects of Asthma on Daily Living and an Investigation of Possible Influential Factors
Authors: Quirk F. H. , Jones P. W. 
Published: August 2015

1. Distress ratings for questions relating to the symptoms and impacts of asthma on daily living have been examined in 40 adult asthmatic outpatients.
2. The patients responded to each item in a 76-item questionnaire by marking a 10 cm visual analogue scale to indicate the degree of distress associated with the symptoms or state described in the question. The resulting score (as a percentage of 10 cm) was interpreted as the degree of distress associated with a particular item.
3. The possible influence on these distress scores of five factors, age, duration (time in years from diagnosis to interview), variability [recorded variability of forced expiratory volume in 1 s (FEV1) expressed as amplitude per cent mean], sex and FEV1 (current and worst recorded in the clinic, expressed as per cent of predicted) was investigated.
4. From correlations of each item with age, 11/76 items were significant at P &lt; 0.05. Taking the results from all 76 items in a repeated measures analysis of variance, there was a small significant relationship between age and distress score (P = 0.048). The direction of the association was negative, suggesting that younger patients were less tolerant of asthma; however, the effect of age only explained 1.5% of the total variance in scores of the 76 items.
5. From correlations of visual analogue scale score for each item against duration, 10/76 items were significant at P &lt; 0.05, but taking the 76 items overall there was no significant association (P = 0.2).
6. The remaining factors, sex, variability and FEV1, only showed a significant effect in 1/76, 1/76 and 5/76 items, respectively (P &lt; 0.05). Taking the 76 items overall did not demonstrate significant effects for any of these factors.
7. We conclude that age, sex, FEV1, duration and variability have little influence as predictors of patients' perception of their distress due to asthma.
Glycosaminoglycan Content, Oxalate Self-Exchange and Protein Phosphorylation in Erythrocytes of Patients with ‘Idiopathic’ Calcium Oxalate Nephrolithiasis
Authors: Baggio Bruno , Marzaro Giovanni , Gambaro Giovanni , Marchini Francesco , Williams Hibbard E. , Borsatti Arturo 
Published: August 2015

1. This study was performed to test the hypothesis that glycosaminoglycans may play an important role in the observed abnormalities in oxalate flux seen in patients with calcium oxalate nephrolithiasis.
2. Oxalate flux rate, erythrocyte membrane glycosaminoglycan content, membrane protein phosphorylation and effect of heparan sulphate on erythrocyte oxalate flux in vitro were studied in control subjects and patients with calcium oxalate nephrolithiasis.
3. In comparison with control subjects, renal stone-formers showed a significantly higher oxalate self-exchange, a lower erythrocyte membrane glycosaminoglycan content and a higher membrane phosphorylation rate. In stone-formers, erythrocyte glycosaminoglycan content correlated inversely with both oxalate flux rate and protein phosphorylation. In vitro, heparan sulphate promoted a significant fall in the rate of oxalate self-exchange.
4. These findings support the hypothesis that a lower erythrocyte membrane content of glycosaminoglycans enhances membrane protein phosphorylation, leading to an increased rate of transmembrane oxalate flux.
Fluoride Therapy and Parathyroid Hormone Activity in Osteoporosis
Authors: Stamp T. C. B. , Saphier P. W. , Loveridge N. , Kelsey C. R. , Goldstein A. J. , Katakity M. , Jenkins M. V. , Rose G. A. 
Published: August 2015

1. To determine the relationships between parathyroid hormone activity and long-term sodium fluoride therapy in osteoporosis, cytochemical bioassays (for biologically active parathyroid hormone) were performed in 22 osteoporotic control patients and in 18 patients after 15 ± 10 months of treatment (60 mg of sodium fluoride daily). Ten patients were studied longitudinally by repeated metabolic balances and were therefore common to both groups. All patients were receiving mineral supplements.
2. Cross-sectional data showed a fourfold mean increase in biologically active parathyroid hormone on fluoride treatment (P &lt; 0.005) together with a 51% increase in serum alkaline phosphatase (P &lt; 0.005). Longitudinal data showed, in addition, a significant increase in the calcium balance of 2.4 ± 1.2 (sem) mmol daily (P &lt; 0.05) and the development of a positive phosphorus balance (P &lt; 0.02).
3. Fluoride-treated patients were then analysed in two groups according to the level of biologically active parathyroid hormone. Thirty-two per cent of values were above the upper limit of normal (18 pg/ml). The mean serum alkaline phosphatase level in this group showed no elevation above that of the control patients, the overall rise being accounted for entirely by patients with normal levels of biologically active parathyroid hormone. High levels of biologically active parathyroid hormone were also associated with relative hypophosphataemia (P &lt; 0.01), relative hypercalciuria (P &lt; 0.05) and an increased urine/faecal calcium ratio (P &lt; 0.025).
4. Results show that long-term fluoride and calcium therapy increase biologically active parathyroid hormone in osteoporosis and that excessive parathyroid hormone activity may account for certain features of the refractory state.
Effects of Blood Glucose Concentration on Thermogenesis and Glucose Disposal during Hyperinsulinaemia
Authors: Gallen I. W. , MacDonald I. A. 
Published: August 2015

1. The thermogenic and cardiovascular responses to glucose ingestion or infusion are altered by undernutrition. These changes may be due, in part, to alterations in the blood glucose concentration. This study investigates the effect of variation in the blood glucose concentration on the thermogenic and cardiovascular responses to a hyperinsulinaemic glucose clamp.
2. Ten healthy post-absorptive subjects (six male, aged 21–30 years) were studied on two occasions. Baseline measurements were made for 30 min, followed by a 90 min continuous insulin infusion (100 m-units min−1 m−2), during which the arterialized venous blood glucose concentration was maintained at 4.5 mmol/l (euglycaemia) or 3.5 mmol/l (mild hypoglycaemia). Measurements were made of glucose infusion rate and respiratory gas exchange from which glucose storage and oxidation and metabolic rate were calculated.
3. During the final 30 min of each hyperinsulinaemic clamp, the rates of glucose disposal (53.5 ± 1.4 versus 38.2 ± 1.0 μmol min−1 kg−1, P&lt;0.01) and glucose storage (32.4 ± 1.1 versus 22.8 ± 1.2 μmol min−1 kg−1, P &lt; 0.05), and the increase in metabolic rate (0.44 ± 0.08 versus 0.11 ± 0.09 kJ min, P &lt; 0.01), were all greater with a blood glucose concentration of 4.5 mmol/l than of 3.5 mmol/l.
4. Plasma noradrenaline rose during the clamp to significantly higher levels at a blood glucose concentration of 4.5 mmol/l (1.18 ± 0.06 nmol/l) than at a blood glucose concentration of 3.5 mmol/l (1.02 ± 0.06 nmol/l, P&lt;0.05), although the absolute changes were not significantly different (+ 0.17 ± 0.06 and +0.14 ± 0.05 nmol/l at blood glucose concentrations of 4.5 and 3.5 mmol/l, respectively). Plasma adrenaline did not change at a blood glucose concentration of 4.5 mmol/l but increased slightly (to 0.36 + 0.04 nmol/l, P&lt;0.05) at a blood glucose concentration of 3.5 mmol/l. During hyperinsulinaemia, heart rate and forearm blood flow rose and diastolic blood pressure fell similarly (P&lt;0.01) at both blood glucose concentrations.
5. Mild hypoglycaemia reduces the thermogenic response to glucose infusion to a greater extent than the reduction in storage, but does not alter the noradrenaline or cardiovascular responses to hyperinsulinaemia. Thus, the cardiovascular and noradrenaline responses during the infusions may be linked and dependent upon the hyperinsulinaemia, whereas some other aspect of glucose metabolism influences the thermogenic response.
Postprandial Substrate Deposition in Human Forearm and Adipose Tissues in Vivo
Authors: Coppack S. W. , Fisher R. M. , Gibbons G. F. , Humphreys S. M. , McDonough M. J. , Potts J. L. , Frayn K. N. 
Published: August 2015

1. Substrate movements in forearm muscle and subcutaneous adipose tissue were studied, by measurement of arteriovenous differences and blood flow, in seven normal subjects after an overnight fast and then for 6 h after ingestion of a mixed meal. Overall substrate balances were examined in terms of the flux of gram-atoms of carbon.
2. As found previously, the forearm was approximately in carbon balance (import equal to export) after the overnight fast, whereas adipose tissue was a net exporter of carbon, mainly in the form of non-esterified fatty acids.
3. After the meal, arterialized plasma concentrations of glucose and lactate rose sharply (peak at 60 min), whereas those of non-esterified fatty acids and glycerol fell (nadir at 60–120 min). Plasma triacylglycerol concentrations rose slowly to peak at 240 min; much of this rise was accounted for by a rise in the chylomicron fraction.
4. Both tissues took up glucose at an increased rate after the meal. Release of non-esterified fatty acids and glycerol from adipose tissue was suppressed. Clearance of triacylglycerol by both tissues increased after the meal, but was more marked in adipose tissue, where the fractional extraction of chylomicron-triacylglycerol reached 44% at 240 min.
5. The forearm rapidly became a considerable net importer of carbon, and remained so until 6 h after the meal when it was again in approximate carbon balance. Glucose uptake dominated the forearm carbon balance. Adipose tissue was a net importer of carbon from 30 min until 5 h after the meal and then reverted to net export. Clearance of triacylglycerol carbon made the largest contribution to this positive balance, but towards the end of the study this was increasingly counterbalanced by simultaneous non-esterified fatty acid release.
6. Skeletal muscle plays a major role, and adipose tissue a minor one, in the disposal of ingested carbohydrate; adipose tissue plays a major role and skeletal muscle a minor one in clearance of dietary-derived triacylglycerol. The role of adipose tissue lipoprotein lipase is not, however, simply the uptake of triacylglycerol for storage within the tissue; rather, it appears to play a central role in the distribution of dietary-derived lipid energy.
Effect of Natriuretic Agents, Vasoactive Agents and of the Inhibition of Metabolism on Sodium Handling in the Isolated Perfused Kidney of the Nephrotic Rat
Authors: Firth J. D. , Ledingham J. G. G. 
Published: August 2015

1. The kidney taken from a rat rendered nephrotic by exposure to puromycin aminonucleoside retains sodium abnormally when perfused in isolation and has an abnormally low vascular resistance (J. D. Firth et al., Clin. Sci. 1989; 76, 387–95). In this study the relation of oxygen consumption to sodium reabsorption has been examined in the isolated nephrotic organ, which has also been exposed to a variety of natriuretic agents and to the effect of inhibition of metabolism by cooling, in an attempt to discern the transport process, or processes, responsible for abnormal tubular handling of sodium. In addition, the effects of three endogenous vasconstrictors, noradrenaline, angiotensin II and endothelin, on the function of the isolated nephrotic kidney have been examined.
2. The ratio of mol of sodium reabsorbed by the tubules of the isolated nephrotic kidney to mol of oxygen consumed was reduced in comparison with the control kidney (means ±sem): 9.22±0.97 versus 15.43 ±1.55 (P &lt; 0.002).
3. In the presence of ouabain (1 mmol/l), acetazolamide (1 mmol/l), frusemide (200 μmol/l), the combination of these three agents together, hydroflumethiazide (100 μmol/l), benzamil (100 nmol/l) or atrial natriuretic peptide (1000 pmol/l), a lesser increment in sodium excretion was induced in the isolated nephrotic kidney than in the control kidney and the nephrotic organ continued to excrete less sodium in both absolute and fractional terms.
4. This suggests that enhanced tubular sodium reabsorption in the isolated nephrotic kidney does not depend upon abnormally increased activity of the Na+/K+-adenosine triphosphatase, bicarbonate-dependent sodium transport, Na+/K+/2Cl− co-transport, electrically neutral proportionate reabsorption of sodium and chloride (distal tubule), epithelial sodium channel (distal tubule) or atrial natriuretic peptide-sensitive sodium transport processes.
5. When isolated nephrotic kidneys and normal kidneys were cooled to 8–10°C the handling of sodium became virtually identical in the two groups. On re-warming to 37°C, the original differences in sodium handling between nephrotic and control kidneys were restored. This implies that the mechanism responsible for the abnormal tendency to retain sodium is temperature-sensitive; as yet it remains otherwise undefined.
6. The sensitivity of the renal vessels to noradrenaline, angiotensin II and endothelin, as judged by the percentage reduction in perfusate flow rate produced by a given concentration of any of these agents, was not substantially altered in the nephrotic kidney compared with the control kidney. Increase in vascular tone was not associated with amelioration of the tendency of the isolated nephrotic organ to retain sodium. Increasing concentrations of angiotensin II caused the filtration rate to increase in the nephrotic kidney. This effect was unexpected: in the control preparation, as anticipated, angiotensin II caused the filtration rate to decrease.
Endothelin Immunoreactivity in Mice with Gram-Negative Bacteraemia: Relationship to Tumour Necrosis Factor-α
Authors: Takahashi Kazuhiro , Silva Ayona , Cohen Jonathan , Lam Hing-Chung , Ghatei Mohammad A. , Bloom Stephen R. 
Published: August 2015

1. To investigate the role of endothelin in Gram-negative bacteraemia and the possible involvement of tumour necrosis factor-α in its pathophysiology, we measured plasma and tissue (lung, kidney and spleen) immunoreactive endothelin levels in Gram-negative bacteraemic mice, with and without passive immunization by anti-(tumour necrosis factor-α) antibody.
2. Plasma immunoreactive endothelin levels were greatly increased after the Escherichia coli injection. Pre-treatment with anti-(tumour necrosis factor-α) antibody did not suppress elevated plasma immunoreactive endothelin levels (P &gt; 0.1).
3. Lung tissue immunoreactive endothelin levels in mice were increased 16 h after the E. coli injection and were not affected by prior passive immunization with anti-(tumour necrosis factor-α) antibody. Immunoreactive endothelin in spleen and kidney was undetectable (&lt; 34 fmol/g wet weight).
4. Injection of rMu tumour necrosis factor-α into mice did not increase plasma immunoreactive endothelin levels.
5. Antibody to endothelin given 30 min after a 90% lethal dose challenge with E. coli did not affect mortality.
6. We conclude that the rise in plasma and tissue endothelin that occurs in Gram-negative bacteraemia is independent of tumour necrosis factor-α.
Effect of theophylline and dipyridamole on the respiratory response to isocapnic hypoxia in normal human subjects
Authors: Parsons S. T. , Griffiths T. L. , Christie J. M. L. , Holgate S. T. 
Published: August 2015

1. Twelve healthy young men took part in this investigation of the effect of oral theophylline and dipyridamole (two drugs known to affect the pharmacological effects of the purine nucleoside adenosine) on the respiratory response to isocapnic hypoxia.
2. The subjects underwent hypoxic rebreathing manoeuvres after 3-day pretreatments with each of the drugs for 12 h and were at least 2 h postprandial. For each in-Minute ventilation, the maximum rate of isometric inspiratory pressure development at the mouth and the ratio of inspiratory duration to total breath duration were analysed breath-by-breath and regressions of these variables upon the haemoglobin oxygen saturation were performed.
3. The slopes and intercepts of the lines describing the relationships of minute ventilation and the maximum rate of isometric inspiratory pressure development at the mouth with haemoglobin oxygen saturation were unaffected by the study drugs, and no differences in the pattern of breathing were observed.
4. We conclude that oral administration of these drugs does not result in alteration of the response of the respiratory system to progressive isocapnic hypoxia.
5. This suggests that either adenosine has no physiological role in hypoxic respiratory control as measured, or that it has opposing peripheral chemoreceptor and central respiratory centre effects which could not be distinguished by the techniques used.
Influence of Neuropathy on the Microvascular Response to Local Heating in the Human Diabetic Foot
Authors: Stevens M. J. , Edmonds M. E. , Douglas S. L. E. , Watkins P. J. 
Published: August 2015

1. The diabetic neuropathic foot exhibits excess arteriovenous anastomotic shunt flow due to a reduced sympathetic vasoconstrictor tone. Local axon reflexes (mediating postural vasoconstriction, for example) are preserved even in severe diabetic neuropathy. This excess shunt flow and its local neurogenic control may be important in the development of complications of the neuropathic limb.
2. The response of arteriovenous anastomoses to local heating was assessed in 13 diabetic patients with neuropathy (12 insulin-dependent), 10 diabetic control patients (seven insulin-dependent) and 10 normal control subjects. The aim was to study the local reflex control of arteriovenous flow when central sympathetic tone had been largely removed.
3. The change in skin blood flow on local heating to 44°C was measured by using a laser Doppler flowmeter in standard environmental conditions with the foot at heart level. Two sites were assessed: (i) the plantar surface of the great toe (a site in which skin blood flow is dominated by arteriovenous shunt flow) and (ii) the dorsum of the foot (a site without anastomotic flow).
4. It was found that when heat was applied to the plantar surface of the great toe in the diabetic patients with neuropathy a paradoxical decrease in flow through arteriovenous anastomoses occurred, flow declining to 65% (P &lt; 0.05) of its resting value. This could be compared with an increase in flow over the same time period of 262% and 228% (P &lt; 0.01) in diabetic control patients and normal subjects, respectively. When the foot dorsum was heated flow increased in a similar fashion in all patient groups, and a decline in flow was not observed.
5. Peak flow at the great toe was significantly lower in the diabetic patients with neuropathy compared with both the diabetic control patients and the normal subjects [23.68 (44.64) flow units versus 57.0 (43.92) flow units and 76.32 (40.88) flow units, respectively, medians and interquartile ranges, P &lt; 0.02].
6. Thus we have demonstrated that in the presence of neuropathy local heating of the toe pulp may produce (i) a paradoxical fall in skin blood flow and (ii) a greatly reduced peak skin blood flow. The importance of this abnormal vascular control in the pathogenesis of complications of the neuropathic limb has now to be determined.
Long-term reproducibility of Borg scale estimates of breathlessness during exercise
Authors: Wilson Rachel C. , Jones P. W. 
Published: August 2015

1. The intensity of breathlessness in normal subjects during exercise was measured on seven occasions over a 40-week study period to assess the long-term repeatability of Borg scale estimates of breathlessness.
2. In all subjects there was a significant correlation (P = 0.0001) between breathlessness and minute ventilation. Minute ventilation measured at each work rate did not differ between the seven exercise tests (P &gt;0.05).
3. There was no significant difference between the mean Borg scores (measured with respect to a given level of ventilation) in 5 of the 7 test weeks (P &gt;0.05). The slope of the relationship Borg score/minute ventilation did not differ between the seven exercise tests (P &gt;0.05).
4. Breathlessness estimation was highly reproducible both after 1 week and after 40 weeks of the study (both P &gt;0.05).
5. The duration without testing between consecutive tests did not affect reproducibility: the mean Borg score was as equally reproducible after an interval of 22 weeks without testing as after an interval of 1 week (P &gt;0.05).
6. The Borg scale provides a reliable technique for studying the sensation of breathlessness over extended time periods.