bluuebunny/crossref_metadata_2025 huggingface dataset:
Mixed venous blood temperature response to exercise in heart failure patients treated with short‐term vasodilators
Authors: Shellock Frank G. , Rubin Stanley A.
Published: April 2008

Summary. Deep‐body or core temperature decreases during exercise in patients with heart failure, primarily due to the circulatory inadequacies associated with the pathophysiology of this condition. Vasodilators are commonly used to treat patients suffering from heart failure because these drugs improve total cardiac output and blood‐flow to the regional circulations. In heart failure patients, the core temperature response to exercise should also be affected if the circulation is improved by vasodilators. Patients with severe heart failure were studied at rest and during upright bicycle exercise before, and after, short‐term treatment with vasodilators (2‐minoxidil, 3‐hydralazine, 5‐captopril). Their heart rate increased significantly (P<005) from rest to exercise before (87±15–109±14 beats/min), and after 89±13–112±15 beats/min) vasodilators, but there was no drug‐related affect on these changes. Mean arterial and pulmonary capillary wedge pressures were significantly (P<0–05) decreased at rest and after the administration of vasodilators (mean arterial pressure 88±7 mmHg before; 77±8 mmHg after; pulmonary capillary wedge pressure 25±8 mmHg before, 19±9 mmHg after). During exercise, the increases in mean arterial and pulmonary capillary wedge pressures were not significantly different from the before vasodilator values (mean arterial pressure 92±14 mmHg before, 87±14 mmHg after; pulmonary capillary wedge pressure 31±11 mmHg before, 29± 11 mmHg after). Vasodilators increased cardiac output significantly (P<0–05) at rest (3‐1 ±0–6 litre/min to 4‐1 ± 1 1 litre/m) and during exercise (4–8±‐2 litre/min‐5–6±l‐7 litre/min). The core temperature (mixed venous blood temperature) decreased significantly (P<0–05) during exercise from 37‐04±0–62oC to 36–65±0–65oC, before treatment with vasodilators. After administration of vasodilators, resting core temperature was not significantly different (36–95±0–54oC) and still decreased significantly (P<0–05) during exercise to 36–73±0–53oC. This decrease was significantly (P<0–05) different from the core temperature response before the administration of vasodilators. We conclude that heart failure patients, treated with short‐term vasodilators, have an
Splenic haemodynamics and portal hypertension in patients with liver cirrhosis and spleen enlargement
Authors: Merkel C. , Gatta A. , Arnaboldi L. , Zuin R.
Published: April 2008

Summary. The relationships between portal hypertension and spleen enlargement, in patients with liver cirrhosis, are not clearly defined; as well as those between splenic haemodynamics and portal hypertension.

In 25 cirrhotics with spleen enlargement and portal hypertension and in seven controls, the following parameters were determined: estimated splenic volume (ESV) from the radiographic view of the spleen, according to Blendis, Williams and Kreel (1969), specific splenic blood‐flow (SSBF), total splenic blood‐flow (TSBF), porto‐hepatic gradient (PHG), specific splenic resistance (SSR) and total splenic resistance (TSR). Moreover, the size and extension of oesophageal varices, at oesophagoscopy, were classified according to Dagradi (1973).

PHG, ESV and TSBF were increased in all subjects, SSBF was increased in two cases, SSR was increased in two cases and decreased in two cases, TSR was decreased in all cases and ESV was not correlated to the level of portal hypertension. Neither TSBF nor TSR were found to be correlated to the level of portal hypertension, as estimated by PHG or by oesophageal varices.

It is concluded that, in patients with liver cirrhosis and spleen enlargement, splenomegaly is likely to be the consequence of pulp hyperplasia and not of passive congestion, and that increases in splenic blood‐flow do not contribute significantly to portal hypertension.
The clearance of Xenon‐133 following its parenchymal injection: a rapid method for estimating functional liver blood‐flow
Authors: Jenkins S. A. , Taylor A. , Shimirty S. K. , Johnson J. , Baxter J. N. , Taylor I. , Shields R.
Published: April 2008

Summary. Portal venous flow, total hepatic blood‐flow and hepatic artery flow were measured in healthy dogs by electromagnetic flowmetry and a double indicator dilution technique. Functional liver blood‐flow was measured by the double indicator dilution technique. Functional hepatic blood‐flow did not correlate with portal venous flow, total hepatic blood‐flow or hepatic artery flow, measured by either electromagnetic flowmetry or a double indicator dilution technique. There was a good correlation (r=0.83, P<0.001) between functional hepatic blood‐flow and liver blood‐flow, measured by the clearance of Xenon‐133 injected directly into the liver parenchyma. It is concluded that the clearance of Xenon‐133, injected directly into the liver parenchyma, is a rapid and simple method for measuring functional hepatic blood‐flow.
Effects of a thromboxane antagonist (BM 13·177) during endotoxin‐induced pulmonary vasoconstriction in sheep
Authors: HüUttemeier P. , Eliasen K. , Mogensen T. , Bell M. , SøSrensen J. NøSrtved , Ovist J.
Published: April 2008

Summary. We investigated the effect of a thromboxane antagonist, BM 13·177, during endotoxin‐induced pulmonary vasoconstriction in sheep. In control animals intravenous E‐coli endotoxin (1 μg/kg) caused a transient increase of pulmonary artery and airway pressure paralleled by large concentration increases of TXB2: in comparison peak plasma concentrations of 6‐keto‐PGFlα (a prostacyclin metabolite) were small and delayed in time. Pre‐treatment with BM 13·177 (bolus 5 mg/kg), followed by 0·75 mg/kg/min intravenously) abolished the rise of pulmonary artery and airway pressure. Plasma concentrations of TXB2 and 6‐keto‐PFGla were similar to controls.

These and previous investigations imply that BM 13·177 specifically antagonizes TXA2 on the putative receptor in pulmonary vascular and airway smooth muscle.
Metabolism of exercising skeletal muscle during beta1‐selective adrenoceptor blockade
Authors: Hartling Ole Johannes , Schibye Bente , Klausen Klaus , Lund Jens Otto , Trap‐Jensen Jens
Published: April 2008

Summary. Concentrations of glycogen, glucose, glucose‐6‐phosphate and lactate in the lateral vastus muscle were measured in seven subjects before and after dynamic muscle exercise at a work load of 75% of each subject's maximal working capacity, and with and without intravenous administration of the beta1‐selective beta‐adrenoceptor blocking agent, atenolol. Pulmonary oxygen uptake was measured during exercise. Heart rate and arterial blood pressure were measured throughout the study. Arterial concentrations of glucose, lactate and free fatty acids were measured at rest and during exercise. The muscle concentration of glycogen and the extent of glycogen depletion with exercise were not influenced by the beta1‐adrenoceptor blocker. Similarly, there was no change in the muscle concentrations of glucose, glucose‐6‐phosphate and lactate. Heart rate decreased at rest and during exercise. Arterial blood pressure was not influenced by beta‐blockade. Pulmonary oxygen uptake decreased by 6·5%. The exercise induced rise in arterial blood concentration of free fatty acids was abolished by beta1‐selective beta‐blockade. It is concluded that the decrease in lactate release from exercising muscles during beta1‐adrenoceptor blockade seen in other studies cannot be explained by an impaired breakdown of muscle glycogen. It may be inferred, however, that a reduced availability of free fatty acids in the exercising muscles during beta1selective (and non‐selective) beta‐blockade may enhance the combustion of pyruvic acid and thereby decrease the production of lactate.
Muscle adaptations and glucose control after physical training in insulin‐dependent diabetes mellitus
Authors: Mandroukas K. , Krotkiewski M. , Holm G. , Strömblad G. , Grimby G. , Lithell H. , Wroblewski Z. , Björntrop P.
Published: April 2008

Summary. Six men and three women with insulin‐dependent diabetes (without complications) participated in physical training three times a week for 20 weeks. Physical training did not change the concentration of fasting blood‐glucose, glucose excretion in urine or glucosylated haemoglobin (HbA1). However, the glucose disposal rate during euglycaemic clamp increased after training. In two patients a minor reduction of insulin dosage was necessary to alleviate slight hypoglycaemic episodes. The training resulted in significant increases in quadriceps isometric and dynamic strength and endurance. Maximal oxygen uptake increased by 8%, the activity of glycolytic enzymes in vastus lateralis muscle by 47% for hexokinase, and 30% for tri‐osephosphate dehydrogenase and 25% for lactic dehydrogenase, the activity of oxidative enzymes by 42% for citrate synthase and 46% for 3‐hydroxy‐acyl‐CoA‐dehydrogenase. The glycogen concentration in the vastus lateralis muscle did not change significantly. Lipoprotein lipase activity did not change in muscle, nor in adipose tissue. The mean muscle fibre area increased by 25% and the area of FTa fibres by 30%. The new formation of capillaries around different muscle fibres was significant for FTb fibres (26%). The proliferation of capillaries, however, appeared to be insufficient to cope with the increased area of muscle fibres. As a result, the mean area of muscle fibre supplied by one capillary (a measure of diffusion distance) significantly increased after training for FTa fibres.

It is concluded that with the exception of deficient proliferation of capillaries, patients with insulin‐dependent diabetes mellitus show a normal central and peripheral adaptation to physical training. Physical training does not apparently improve blood glucose control in most cases, despite an increased insulin sensitivity.
Binding of digoxin to slow‐ and fast‐twitch skeletal muscle fibres
Authors: Joreteg T.
Published: April 2008

Summary. We have found previously great interindividual variations in the binding of digoxin to skeletal muscle even after standardized rest. The present study was performed in order to find out if there is a difference in the binding of digoxin to slow‐and fast‐twitch fibres in man at rest and after moderate exercise. Seven healthy digitalized subjects (digoxin 0·50 mg/day) were investigated after 90 min of supine rest and after a 1 h moderate bicycle exercise. Muscle biopsy specimens were taken immediately before and 5 min after exercise and dissected under a microscope to single fibres. After histochemical typing of all fibres the digoxin content in slow‐and fast‐twitch fibres was measured separately. At rest, digoxin binding to slow‐twitch fibres was 33% higher than to fast‐twitch fibres (P<0·01). During exercise the digoxin binding increased by 28% in slow‐twitch fibres but was unchanged in fast‐twitch fibres. The difference in digoxin binding to the two fibre types may explain, at least partly, the interindividual variations in the binding of digoxin to skeletal muscle.
Thermal dilution assessment of proximal aortic and left ventricular mixing chambers in dogs
Authors: Mickelson J. , Abendschein D. , Carlson C. J.
Published: April 2008

Summary. The adequacy of left ventricular mixing and the effect of mixing in the left ventricle and aorta on the measurement of the residual fraction by thermal dilution were assessed in open‐chest dogs. Temperature was recorded at seven ventricular and two aortic sites during ventricular injections of iced saline at heart rates of 100, 150 and 200 bpm. The residual fraction, K, was calculated for each beat from the inscribed dilution curves and compared with the actual temperature at each measurement site and heart rate. Temperature was non‐uniform throughout the ventricle after saline injections indicating incomplete tracer mixing. Thermal equilibration was slowest at the apex and decreased as heart rate increased. K, however, was similar for all sites in the ventricle and aorta at each heart rate by the third beat after saline injection. Thus, in spite of incomplete mixing, the beat‐to‐beat washout of indicator quickly stabilized which suggests that a reproducible measurement of functional volume can be obtained by this technique.
The transcapillary exchange of sodium fluorescein in ischaemic limbs measured by fluorescein flowmetry
Authors: Perbeck L. , Sevastik B. , Sonnenfeld T.
Published: April 2008

Summary. The transcapillary exchange of sodium fluorescein in the skin of 36 extremities (19 patients) with arterial occlusive disease was measured using two different ways of analysing the tissue fluorescence, fluorescein flowmetry (FF) and dynamic fluorescein angiography (FA). 7 mg sodium fluorescein/kg body weight was given intravenously. With FF, the transcapillary exchange of sodium fluorescein is expressed in arbitrary units as a fluorescence index. With FA, the time interval from the bolus injection to the first appearance of the fluorescence in the tissue is measured. There was an inverse correlation between pain and fluorescence index. All eight extremities with a fluorescence index of 0·001 density units/s or lower needed amputation, whereas all extremities with higher indices were viable. All extremities requiring amputation had an appearance time of 150 s or more, which contrasted with those remaining viable, having an appearance time of 120 s or less. The results indicate that FF as well as FA are appropriate methods to measure a ‘nutritive’ transport of solutes in the skin. Theoretically, however, if quantitative values for blood flow are required, we recommend FF, this method being more adequate, since it is influenced both by the fraction of cardiac output distributed to the tissue and by cardiac output itself. If, however, only a prognosis of a limb's viability is needed, FA is sufficient, being easier to perform, only requiring the measurement of the appearance time.
Interleukin 1, tumour necrosis factor‐alpha (cachectin) and the pathogenesis of cancer cachexia
Authors: Moldawer L. L. , Georgieff M. , Lundholm K.
Published: April 2008

Summary. Soluble proteins synthesized and released by phagocytic cells may be responsible for the protein and energy wasting frequently observed during catabolic states, including cancer cachexia. This hypothesis is based upon the observation that many of the hosts's metabolic responses to infection, inflammation, accidental trauma and some forms of cancer are remarkably similar. Anorexia and degradation of skeletal and connective tissue protein, as well as increases in hepatic protein synthesis and energy expenditure, can all be reproduced by the administration of activated macrophage products. During inflammatory states, including active tumour growth, increased production of some cytokines, including interleukin 1 and tumour necrosis factor‐alpha (cachectin), have been observed. If these monokines serve as metabolic inducers, then efforts to block therapeutically the actions of macrophage‐secreted substances may play a role in slowing the progression of tissue‐wasting associated with catabolic states, particularly due to malignant tumours.
Respiratory airflow pattern in patients with chronic airway obstruction
Authors: Minetti A. E. , Brambilla I. , Lafortuna C. L.
Published: April 2008

Summary. Previous experimental evidence has shown that in healthy humans inspiratory airflow waveform can be optimized according to minimum rate of work criteria when the respiratory energetic requirements become a substantial fraction of the general metabolism (i.e., during exercise hyperpnea and maximum voluntary ventilation). In patients with chronic airway obstruction (CAO) the relative energetic expenditure devoted to respiration is also greatly enhanced at rest. To investigate the performance of a system also controlling airflow wave pattern in this condition we evaluated by Fourier analysis the harmonic content of respiratory flow waves recorded at rest and during exercise hyperpnea (25 and 50 W on cycloergometer) in 15 patients. The results were compared with those we previously obtained in normal subjects and with some theoretical models. It was found that, while normal subjects display at rest an inspiratory flow waveform reasonably close to a sinusoidal model and adopt a more rectangular and economical flow shape during exercise hyperpnea, patients with CAO show a rather rectangular inspiratory flow shape also at rest, without any remarkable change at higher levels of ventilation. So, in general terms, the airflow pattern employed by patients at rest entails a reduction in the rate of dynamic inspiratory work of about 12% over that required by a sinusoidal waveform, and no further advantage is observed during exercise hyperpnea. Some features of the expiratory flow wave were also analysed. As no model of the respiratory system mechanics presently developed can explain the findings obtained in CAO patients purely on the basis of their altered mechanical parameters, it has been suggested that more complex control of respiratory airflow is operating in this class of patient.
Increased sympathetic tone in forearm subcutaneous tissue in primary hypothyroidism
Authors: Nielsen H. Vagn , Hasselström K. , Feldt‐Rasmussen U. , Mehlsen J. , Siersbæk‐Nielsen K. , Friis Th. , Haunsø S. , Trap‐Jensen J.
Published: April 2008

Summary. Sympathetic reflex regulation of subcutaneous blood flow (SBF) in the forearm was studied in eight patients with primary hypothyroidism. Diastolic arterial pressure was ≥95 mmHg in five patients. SBF was determined by local clearance of Na99mTcO4.

Sympathetic vasoconstriction normally seen after lowering the forearm 40 cm below heart level was absent since SBF only decreased by 4% (± 7%, P > 0·1) during these conditions. In head‐up vertical position we noticed a diminished baroreceptor response as SBF at heart level was reduced by 11% (±7%, P < 0·1) compared to supine position. After proximal local anaesthesia SBF increased by 351% (±81%, P < 0·01) and disclosed a normal vasoconstrictor response as SBF was reduced by 53% (±5%, P < 0·01) during arm lowering.

Five of the treated patients were restudied in the euthyroid state. Mean arterial pressure was reduced in mean by 20 mmHg (± 6 mmHg, P < 0·02) during treatment and a significant vasoconstriction was observed both during arm lowering (SBF =‐52% (±6%, P<0·02)) and in head‐up vertical position (SBF= ‐45% (± 11%, P<0·02)).

In conclusion sympathetic vasoconstrictor activity in adipose tissue is markedly increased in primary hypothyroidism. Sympathetic tone and arterial pressure are reduced during treatment.
ATP and IMP in single human muscle fibres after high intensity exercise
Authors: Jansson E. , Dudley G. A. , Norman B. , Tesch P. A.
Published: April 2008

Summary. Within a muscle there is large variation in the activity of various enzymes among single fibres. It is reasonable, therefore, to expect a corresponding variation in their metabolic response to exercise. This was examined by obtaining muscle biopsies from five men at rest and after intense short‐term exercise consisting of three bouts of 30 knee extensions each and intervened by 60 s rest. Freeze‐dried dissected single fibres identified as type 1 or type 2 were analysed for ATP and IMP contents by liquid chromatography. Rest. Average ATP tended to be higher in type 2 than in type 1 fibres. The ATP range was 14–30 and 14–32 mmol × kg‐1 dry muscle (dm) in type 1 and 2 fibres, respectively. IMP was less than 1 mmol × kg‐1 dm in most fibres and similar in types 1 and 2. Exercise. Muscle force decreased 70% during exercise. The average decrease in ATP content was significant for both fibre types with somewhat larger response for type 2 (20%) than type 1 (10%) fibres. The ATP range was 10–28 and 10–30 mmol × kg‐1 dm in type 1 and 2 fibres, respectively. Average IMP content increased substantially in both fibre types, more so for type 2, and the range for individual fibres was 0–13 (type 1) and 0–21 (type 2) mmol × kg‐1 dm. Conclusion. After exhaustive short‐term exercise, a large variation in ATP and IMP contents was evident among single type 1 and type 2 fibres. None of the fibres, however, showed an ATP content lower than 10 mmol × kg‐1 dm. It is suggested that the muscle force loss, demonstrated in the present study, is not attributed to a lowered ATP content per se.
Long‐term effects of beta‐adrenergic blockade with nadolol on hepatic and renal haemodynamics and function in cirrhotics
Authors: Gatta A. , Bolognesi M. , Merkel C. , Finucci G. F. , Angeli P. , Sacerdoti D. , Ruol A.
Published: April 2008

Summary. Non‐cardioselective beta‐blockers are used for prevention of re‐bleeding from oesophageal varices in cirrhotics with portal hypertension. Nadolol, a non‐cardioselective beta‐blocker with a low liposolubility and a low hepatic metabolism, has been demonstrated to decrease portal pressure in cirrhotic patients. Since cirrhotics need long‐term treatment, we investigated long‐term effects of beta‐adrenergic blockade with nadolol on hepatic and renal haemodynamics and function in a group of patients with cirrhosis and portal hypertension. In 19 patients with cirrhosis, after one and six months of treatment with nadolol hepatic venous pressure gradient showed a significant and persistent decrease, averaging 19% and 22%, respectively. Hepatic function and renal haemodynamics and function remained unaffected. Oesophageal varices severity was lowered in 11/19 patients after one month, in 9/16 after six months, in 8/14 after 12 months and in 5/10 after 18 months. Our results showed that, also after long‐term treatment, nadolol decreases portal pressure and, in approximately 50% of patients, oesophageal varices severity, without side‐effects on liver and renal function.
Local myocardial function following coronary occlusion in cats, Effect on non‐ischaemic regions
Authors: Matre K. , Hexeberg E. , Grong K. , Lekven J.
Published: April 2008

Summary. The mechanical function and perfusion in ischaemic and non‐ischaemic myocardium after coronary occlusion was studied in 10 cats using pressure‐length loop analysis and radiolabeled microspheres. Measurements in three regions—ischaemic, adjacent normal and remote normal myocardium—all showed different responses to coronary occlusion. In the ischaemic region loop area, segment shortening and tissue flow were markedly reduced. In the adjacent normal region, both loop area and segment shortening as well as flow increased. In the remote normal region, neither loop area, segment shortening nor flow showed consistent changes. End‐diastolic segment length increased in all regions, most in the ischaemic region and least in the remote region. The increased end‐diastolic segment length in all regions after coronary occlusion indicates activation of the Frank‐Starling mechanism as an attempt to maintain stroke volume. However, the end‐diasolic segment length did not increase uniformly for all normal myocardium: it depended on the proximity to the ischaemic region. Increased contractile function in the adjacent normal myocardium due to non‐uniform distribution of the Frank‐Starling effect is the most likely mechanism behind the left ventricle's ability to partially compensate for loss of contractile mass during acute regional ischaemia in anaesthetized cats.
Sex‐ and age‐related normal limits for the QRS complex in vectorcardiography
Authors: Edenbrandt L. , Jonson B. , Lundh B. , Pahlm O.
Published: April 2008

Summary. In order to provide reference values for vectorcardiography (VCG), which are relevant with regard to sex. age and available computer technology. VCG from a normal material were studied. VCG according to Frank were recorded in 159 men and 193 women, healthy and randomly selected from a defined Caucasian urban population. The technique used includes noise reduction by averaging and a spatial algorithm for QRS delineation. The results are given separately for men and women and for young and old subjects. Significant differences between these groups were found to be common and of potential importance for interpretation of VCG. Discrepancies between our results and other reports on normal ranges can be explained by both different techniques used and different composition of the material studied. On the basis of our data normal limits for a number of measurements, commonly used in diagnostic criteria for myocardial infarction and ventricular hypertrophy are reported.
Haemodynamic response to exercise in patients with alcoholic liver cirrhosis
Authors: Kelbæk H. , Rabøl A. , Brynjolf I. , Eriksen J. , Bonnevie O. , Godtfredsen J. , Munck O. , Lund J. O.
Published: April 2008

Summary. Physical work capacity was evaluated by a multistage bicycle exercise test in 29 patients, 22 men and seven women aged 35–61 years (mean 49) with alcoholic liver cirrhosis and in a sex‐ and age‐matched control group. The maximal work load was reduced in the patient group, mean 122 vs. 186 watts in men (P < 0·001), and 60 vs. 119 watts in women (P < 0·005). Resting heart rate was higher in patients (91 vs. 78 beats × min1, (P < 0·005), and the maximal heart rate was lower (159 vs. 170 beats × min‐1, (P < 0·001) compared with controls. Thirteen of 29 (45%) patients compared with 5 of 29 (17%) control subjects had an increase in left ventricular ejection fraction of ≤5% during exercise (P < 0·05).

The present results suggest that an impaired capacity of the cardiac function to respond adequately to physical stress may at times contribute to the reduced physical work capacity seen in patients with alcoholic liver cirrhosis.
Myocardial energy metabolism in the induction phase of cardioplegia in relation to myocardial temperature during open heart surgery
Authors: Jansson E. , Bomfim V. , Schmid W. , Kaijser L.
Published: April 2008

Summary. Changes in myocardial high energy phosphate and lactate concentrations during initiation of cardioplegia for open heart surgery were studied in 21 patients and related to their individual myocardial temperatures. Left ventricular myocardial biopsies were taken 10 min post aortic cross‐clamping and were analysed for ATP, creatine phosphate (CP), creatine (C) and lactate. The patients were divided into three groups according to the achieved myocardial temperature: 6–10°C, 11–15°C and 16–24°C. The results indicated that optimal myocardial protection during the induction phase of the cardioplegia was obtained in the 11–15°C group in which the highest ATP concentration and simultaneously lowest lactate concentration was maintained.
Increase of plasma renin activity at renal blood flow estimations with the Xenon133 wash‐out technique in patients with renal artery stenosis
Authors: Hägg A. , Åberg H. , Lörelius L.‐E. , Mörlin C. , Wide L.
Published: April 2008

Summary. Eleven patients with hypertension and renal artery stenosis of fibromuscular type were investigated with renal blood flow estimations with Xenon133 wash‐out technique before and after alpha‐receptor blockade with infusion of phenoxybenzamine in the stenosed renal artery. During the whole investigation frequent blood samples for renal vein renin estimations were drawn from both kidneys. Immediately after the Xenon injection renal vein renin elevations on the investigated side were observed in 9/11 patients. The renin peak was reached in 10 min and the mean increase for all patients was 152%. The mean duration of the peak was 19·25 min. A neurogenic renin release mechanism triggered by renal chemoreceptors and mediated by beta‐adrenergic fibres was suggested. This finding with renin release stimulation at Xenon113 infusion in the renal artery is of great importance in judging results of investigations concerning renal blood flow and renin when the Xenon wash‐out technique is used. Blood samples for renin estimations should not be taken within 25 min after intrarenal Xenon113 infusions.
Effect of training on the post‐exercise ankle blood pressure reaction in patients with intermittent claudication
Authors: Jonason T. , Ringqvist I.
Published: April 2008

Summary. The effect of physical training on the post‐exercise blood pressure reaction in the ankle was studied in 63 patients with intermittent claudication but without angina pectoris. After three months of supervised training the maximal walking distance increased by 67% and the pain‐free walking distance by 73%. Compared with that after the pre‐training treadmill test, the ankle blood pressure was significantly higher 2–16 min after the post‐training test and more rapidly returned to the initial resting value, both with similar work loads and with a higher post‐training work load. Blood pressure measurement in the ankle after exercise is useful as an objective test of the circulatory effect of training in patients with intermittent claudication.
Acetylstrophanthidin does not enhance the reflex pressor response to static muscular contraction
Authors: Rybicki K. J. , Sanusi H. A. , Kaufman M. P.
Published: April 2008

Summary. Cardiac glycosides have been shown to enhance the sensitivity of the reflex cardiovascular responses to stimulation of mechanoreceptors in the heart, carotid sinus and aorta. Little is known, however, about the effect of glycosides on the reflex cardiovascular responses to the contraction‐induced stimulation of afferent endings in hindlimb skeletal muscle. We therefore examined the reflex heart rate and arterial pressure responses to static contraction of the hindlimb muscles before and after femoral arterial injection of two doses of acetylstrophanthidin (20 and 80 μ/kg). Neither of the two doses enhanced the reflex cardiovascular responses to contraction, although the larger of the two significantly increased femoral venous potassium concentrations from 3·4±0·2 to 3·8±0·1 mM. Although injection of the two doses as well as injection of a very large dose of acetylstrophanthidin (400 μg/kg) increased baseline mean arterial pressure, these effects were probably caused by the vasoconstrictor action of this agent and not by a chemoreflex, because the increase was not attenuated by denervation of the hindlimb.
Determination of the mean transit time for the transport of aerosolized 99mTc‐DTPA across the pulmonary epithelial membrane. A plasma sample method
Authors: Groth S. , Lassen N. A. , Rossing N.
Published: April 2008

Summary. During the last decade it has been customary to estimate pulmonary epithelial permeability (P‐P) as the pulmonary clearance of inhaled nebulized 99mTc‐DTPA from a time‐activity (t‐a) curve registered externally by monitoring over the chest. The t‐a curve, however, is not defined by the degree of P‐P alone but also by factors such as the deposition of the 99mTc‐DTPA in the lungs. To avoid these problems a plasma sample method was derived. It describes P‐P by the mean transit time (t̄) for the transport of 99mTc‐DTPA across the pulmonary epithelial membrane, t̄ (L). The calculation of t̄ (L) involves two steps. Following the inhalation of Tc‐DTPA the plasma t‐a curve is defined and used to calculate t̄ for the transport for 99mTc‐DTPA across the pulmonary epithelial membrane, through the E?V and until elimination by the kidneys, t̄ (L+ECV). Subsequently, 99mTc‐DTPA is injected as a bolus i.v. and the new t‐a curve is used to calculate t̄ for the transport of 99mTc‐DTPA through ECV to the kidneys, t̄ (ECV). Finally t̄ (L) is calculated as t̄ (L) = ‐t̄ (L+ECV) t̄ (ECV). We applied the method in nine non‐smoking individuals (median age 25–5 years, range 20–28) and compared the results to t̄ as calculated from the initial slope of an externally derived t‐a curve. The individual t̄ (L) values were systematically greater than those of the external detection method (P<0·05). It is concluded that the initial slope method overestimates total PCI as measured by the plasma sample method. When choosing between the two methods, special interest should be paid to the inherent problems of the methods.
Total lung capacity measured by body plethysmography and by the helium dilution method. A comparative study in different patient groups
Authors: Andersson L. G. , Ringqvist I. , Walker A.
Published: April 2008

Summary. The helium dilution method is known to underestimate the total lung capacity (TLC) in patients with poorly or non‐ventilated areas in the lungs. The standard plethysmographic method has been reported to overestimate TLC in patients with severe airway obstruction. To determine the magnitude of the difference between the two methods, a comparison was made in different patient groups. In a group of patients with normal lung function tests (n= 20) there was a small but significant average difference in TLC between plethysmography and the helium dilution method, the larger values being obtained with the latter. In patient groups with moderately obstructed airways (n= 23), severely obstructed airways (n= 20), or emphysema (n= 19), there were no significant average differences, although in two patients in the emphysema group the plethysmographic values were considerably larger than those obtained by helium dilution. We conclude that the gas dilution methods and plethysmography with a pressure‐compensated volume displacement plethysmograph gave estimates of TLC which agreed even in patients with airway obstruction or emphysema, except in patients with very severe lung disease.
Plasma lipid and lipoprotein profile in elderly male long‐distance runners
Authors: Higuchi M. , Fuchi T. , Iwaoka K. , Yamakawa K. , Kobayashi S. , Tamai T. , Takai H. , Nakai T.
Published: April 2008

Summary. The purpose of this study was to evaluate plasma lipid and lipoprotein profiles in 30 elderly male long‐distance runners (aged 66 ± 5 years, body fat 12 ± 2%, mean ± SD) by comparing them with 30 middle‐aged untrained men (43 ±8 years, 17 ±3%), 30 middle‐aged endurance‐trained men (45 ±8 years, 12 ± 2%) who were matched for training distance to the elderly runners, and 15 elderly sedentary persons (65 ± 4 years, 16 ± 4%). Both elderly and middle‐aged runners averaged 43 km/week in the latest year. Maximal oxygen uptake in the elderly runners (48 ± 5 ml/kg/min) was 60% higher than in age‐matched untrained men, but 15% lower than in middle‐aged runners. Plasma high‐density lipoprotein cholesterol (HDLC) was significantly higher in the elderly runners than in their age‐matched counterparts (77 vs. 59 mg/dl), but not different from the middle‐aged runners. The middle‐aged runners had lower plasma low‐density lipoprotein cholesterol (LDLC) concentrations than their untrained counterparts (114 vs. 129 mg/dl), whereas LDLC level in the elderly runners was almost identical to that of the age‐matched untrained men (127 vs. 119 mg/dl). Total cholesterol concentration in the elderly runners (219 mg/dl) was 11% higher than in the age‐matched untrained men, whereas there was no difference between the middle‐aged trained and untrained men. The remarkable reduction of the LDLC/ HDLC ratio in the elderly runners, therefore, is attributable to the elevated HDLC rather than lowered LDLC compared with the age‐matched sedentary men (1·7 vs. 2·2). The elderly runners had plasma triglyceride concentrations similar to those of the middle‐aged runners, and lower than those of the sedentary men. These results suggest that regularly performed endurance exercise favourably modifies the lipid and lipoprotein profile, and may thus reduce the risk of developing coronary heart disease for elderly men.
Human tibialis anterior contractile responses following fatiguing exercise with and without β‐adrenoceptor blockade
Authors: Alway S. E. , Hughson R. L. , Green H. J. , Patla A. E.
Published: April 2008

The effects of oral propranolol (2 × 80 mg/day) on the contractile responses to twitch and tetanic electrical stimulation were examined in the tibialis anterior (TA) muscle of seven healthy young males. The TA muscle was fatigued by four forms of repeated isometric contractions: (1) maximal voluntary contractions (MVC), (2) MVC with circulation occluded, (3) electrically evoked contractions with 20 Hz supramaximal voltage stimulation and (4) electrically evoked contractions with circulation occluded. Each contraction was sustained for 10 s with 5 s recovery. Duration of exercise was 10 min for intact circulation and 4 min for circulatory occlusion. Pre‐exercise, both the twitch contraction time and the 1/2 relaxation time were significantly (P<0·05) longer with β‐blockade than placebo, β‐blockade did not affect torque output during tetanic stimulation or MVC. Immediately post‐exercise, the peak twitch torque was reduced in all β‐blocked and placebo conditions except electrically induced exercise with intact circulation. The 1/2 relaxation time was significantly lengthened by repeated MVC with circulation intact; β‐blockade caused a greater lengthening than placebo (P<0·05). The tetanic torque was reduced immediately post‐exercise at each of 10, 20, 50 and 100 Hz for both β‐blockade and placebo for each form of exercise. There were no significant β‐blockade effects. Torque output at 10 Hz was still reduced up to 10 min post‐exercise. In contrast, 100 Hz torque output recovered by 5 min post‐exercise. The changes in tetanic responses were qualitatively similar with intact circulation and with circulatory occlusion. In the tibialis anterior muscle, the effects of fatiguing exercise are not accentuated by β‐blockade. These data in the TA are notably different from those in the triceps surae, where greater fatigue has been shown with β‐blockade.
Glomerular filtration rate estimated from a single plasma sample after contrast‐enhanced radiological examinations
Authors: Boijsen M. , Jacobsson L. , Tylén U.
Published: April 2008

In twenty‐six patients examined with radiographic procedures, including a single injection of meglumine metrizoate, blood samples were drawn 180,200,220 and 240 min after injection. Plasma was analysed for iodine concentration with X‐ray fluorescence analysis and the total plasma clearance of metrizoate was calculated with the single sample method from each sample.

The results were compared with the total plasma clearance of 51Cr‐EDTA, calculated from multiple samples and determined no more than a few days apart from the X‐ray examination. A good correlation, ranging from 0·91 and 0·94, was found. We therefore conclude that kidney function can be estimated from a single plasma sample after contrast‐enhanced radiological examinations.
Glomerular filtration rate in adults estimated from 123iodine‐hippuran and 99mtechnetium‐diethylenetriaminepenta‐acetic acid gamma camera renography
Authors: Carlsen O. , Nathan E.
Published: April 2008

Summary. In a retrospective study a close relationship was found between the rate constant for renal clearance of the radioactive indicator (λpk) and the glomerular filtration rate (GFR) measured by 51Cr‐EDTA plasma clearance. The material comprised eighteen adult subjects submitted to 123I‐hippuran gamma camera renography (IHGR) and twenty‐two adult subjects to 99mTc‐DTPA gamma camera renography (TDGR). The rate constant was calculated from a bi‐exponential decomposition of the activity‐time curve recorded within a small region of interest over the left ventricle. The total cleared renal fraction (TCRF) of the cardiac output with respect to the radioactive indicator has previously been shown to be closely related to GFR. A pooled estimate of GFR (GFRp) was calculated from the stochastically independent estimates of GFR based on λpk and TCRF. The comparison of GFRp with measured GFR was satisfactory and yielded substantially smaller standard deviations (SD) of GFRp than estimates based on λpk and TCRF separately. The standard deviations of GFRp were about 7 and 12 ml/min/1·73 m2 in IHGR for GFR equal to 50 and 100 ml/min/1·73 m2, respectively. The corresponding SD in TDGR were about 7 and 11 ml/min/1·73 m2. These standard deviations are sufficiently small for many clinical purposes and the method requires no blood samples or urine collections.
Whole body fat oxidation before and after carnitine supplementation in uremic patients on chronic haemodialysis
Authors: Lundholm K. , Persson H. , Wennberg A.
Published: April 2008

Summary. This study has evaluated whether uremic patients on chronic haemodialysis with subnormal plasma levels of free carnitine show any alterations in whole body fat oxidation before and after one week with carnitine supplementation (60 mg/kg/day).

Carnitine plasma levels changed from subnormal to supranormal levels of both free and total carnitine concentrations. This increase was not associated with any alteration in either oxygen uptake, carbon dioxide production, respiratory quotient or blood substrate levels such as glucose, glycerol, free fatty acids and lactate. The fractional oxidation of an intravenously infused fat emulsion (Intralipid®) was 17% before and 19% after carnitine supplementation. No side effects were observed in spite of the rather high dose of carnitine administration.

This study failed to demonstrate any impact on net whole body fat oxidation in carnitine substituted uremic patients with initially subnormal levels of free plasma carnitine.
The effect of IV indomethacin on the gastric mucosal electrical potential difference and blood flow in anaesthetized dogs
Authors: Højgaard L. , Ewald H. , Holm I. E. , Bünger C. , Krag E. , Bülow J. B.
Published: April 2008

Summary. Indomethacin inhibits prostaglandin synthesis and causes gastric mucosal damage. The correlation between the gastric mucosal function and gastric blood flow was investigated. The intragastric liquid junction corrected potential difference (PD) across the stomach wall was used to characterize the gastric mucosal function. Mucosal blood flow was determined by the radiolabeled microsphere technique. Seven dogs were anaesthetized, intragastric PD was measured continuously and blood flow determined at basal condition during sympathetic activation, and after IV indomethacin (7·5 mg/kg). PD was unchanged during the basal period and during mild sympathetic activation. After indomethacin PD was reduced significantly (‐40 ± 6 mV to ‐20±5 mV, measured with gastric lumen negative, mean and SD, P<0·05). Mucosal blood flow decreased during sympathetic activation and a further significant reduction was seen after indomethacin. PD and flow reductions correlated (R= 0·92). As indomethacin given IV caused a parallel impairment of gastric mucosal function and blood flow, part of the indomethacin‐related mucosal damaging effects might be due to the flow reduction.
The Q‐oTc and Q‐Tc interval and ionized calcium in newborns
Authors: Nelson N. , Illés L.
Published: April 2008

Summary. Ionized calcium (CaF), Q‐oTc and Q‐Tc intervals were determined in 31 full‐term healthy newborns, 12 infants subjected to blood exchange transfusion (ET) and 10 infants with verified clinical hypocalcaemia.

There was no significant correlation between CaF values and QT intervals. The large fluctuations in CaF during ET did not correspond to any similar change in Q‐oTc or Q‐Tc intervals.

The Q‐oTc interval was slightly longer in the hypocalcaemic and the blood exchanged groups compared to controls. The Q‐Tc interval was somewhat longer in the ET group.

The differences in mean values for QT intervals were fairly small and the ranges wide.

ECG findings lack practical implications in diagnosing and following neonatal hypocalcaemia and we therefore recommend the measurement of CaF as a guideline.
Effect of oral administration of nifedipine on neuropeptide Y‐ and noradrenaline‐induced vasoconstriction in the human forearm
Authors: Pernow J. , Lundberg J. M. , Kaijser L.
Published: April 2008

Summary. Neuropeptide Y (NPY) has recently been shown be co‐released with noradrenaline (NA) from sympathetic nerves and to cause arterial vasoconstriction in experimental animals and man. The effect of a single oral dose (10 mg capsule) of nifedipine on NPY‐ and NA‐induced reductions of forearm blood flow (FBF) was studied in seven healthy volunteers. Intra‐arterial infusions of NPY and NA into the brachial artery before nifedipine caused dose‐dependent reductions in FBF with threshold doses of 0.2 and 0.03 nmol x min‐1, respectively. The response to NPY was slower in onset and more long lasting than that to NA. Forty‐five min after administration of nifedipine, FBF and heart rate had increased significantly (by 49% and seven beats x min‐1, respectively, P<0.001), while no significant change was observed in systemic blood pressure. The NPY‐induced decrease in FBF was slightly but significantly attenuated after compared to before nifedipine (19 ± 6 vs. 28 ± 5% at 1.0 nmol NPY x min‐1; P<0.01). The response to NA was, however, not significantly altered by nifedipine. In conclusion, the NPY‐induced reduction in FBF in man was only slightly prevented and the NA response not significantly affected by oral nifedipine administration in a clinically used dose. This suggests that this calcium antagonist, in the present dosage, does not, to any major extent, inhibit the vasoconstrictor effect of NPY or NA in man in vivo.
Does α1‐adrenergic blockade influence regional blood flow regulation in hearts with coronary artery occlusion?
Authors: Westby J. , Kvitting P. , Birkeland S. , Grong K. , Lekven J.
Published: April 2008

Summary. The effects of selective α1‐adrenergic blockade with doxazosin on regional myocardial tissue blood flow was studied in anaesthetized cats with acute coronary artery occlusion. Reflex tachycardia was prevented by selective β1‐adrenergic blockade with atenolol and coronary perfusion pressure was kept constant by partial stenosis of the descending aorta. Administration of atenolol reduced cardiac mechanical work‐load by its negative inotropic and chronotropic effects, and reduced myocardial tissue blood flow in normally perfused myocardium. This reduction was most pronounced in the endocardial half‐layer of the myocardium adjacent to the ischaemic region. Administration of doxazosin in this situation clearly reduced peak systolic and coronary perfusion pressure. But when coronary perfusion pressure was raised to pre‐administration values, measurements of regional blood flow revealed no changes either in ischaemic or non‐ischaemic myocardium. Also, there was no sign of redistribution of blood flow between endocardial and epicardial tissue in any area. This study, therefore, indicates that α1‐adrenoceptors play a minor role in the regulation of coronary blood flow in normal myocardium as well as ischaemic myocardium.
Relation of running distance to plasma HDL‐cholesterol level in middle‐aged male runners
Authors: Higuchi M. , Iwaoka K. , Fuchi T. , Kobayashi S. , Tamai T. , Takai H. , Nakai T.
Published: April 2008

Summary. This study examined the relation of training distance to plasma high density lipoprotein cholesterol (HDLC) concentration in runners. Forty‐eight male endurance runners, aged from 30 to 57 years, were classified into three groups according to training distance (Grade I: n= 12, 30 km/week; Grade II: n= 22, 60 km/week; Grade III: n= 14, 100 km/week in average running distance), with 12 non‐lean and 12 lean subjects as age‐matched untrained controls. There were no significant differences in plasma total cholesterol among the groups (194–208 mg/dl on average). HDLC level was significantly higher in the untrained, lean group than in the untrained, non‐lean men (63 ± 13 vs. 46 ± 8 mg/dl, mean ± SD). HDLC levels in all the runner groups were significantly higher than in untrained, lean subjects, and no differences were observed among Grade I, II and III runner groups (76 ± 15, 76 ± 13, 77 ± 11 mg/dl, respectively). This study suggests that further increases in HDLC could not occur in response to further elevation of training distance in well‐trained runners.