bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regional extra vascular lung density and fractional pulmonary blood volume in patients with chronic pulmonary venous hypertension
Authors: Wollmer P. , Modes C. G. , Allan R. M. , Maseri A. , Fazio F. 
Published: April 2008

Summary. Using a technique based on positron transmission and emission tomography, we measured regional extravascular lung density (lung tissue and interstitial water per unit thoracic volume) and fractional pulmonary blood volume (volume of blood per unit thoracic volume) in normal subjects and in patients with cardiomyopathy and chronic pulmonary venous hypertension.We found an increase in extravascular lung density in the patients. Extravascular density was increased in all parts of the lung studied, but higher values were seen in the dorsocaudal portion than in the ventrocaudal portion of the lung (average 151% and 130% of normal, respectively). Fractional blood volume was markedly reduced in the dorsocaudal part of the lung (mean 74% of normal).The increase in extravascular density probably reflects structural changes in the lung as well as accumulation of interstitial fluid. The distribution of extravascular density is consistent with previous radiological and morphological studies, and may reflect a higher tendency to oedema formation in the dependent parts of the lung. The measurements of fractional blood volume suggest that intrapulmonary blood volume is reduced in chronic pulmonary venous hypertension. This may reflect a decrease in the distensibility of the pulmonary vessels due to structural abnormalities, as well as functional changes in the pulmonary vasculature.
Pedal blood flow and transcutaneous PO2 in normal subjects and in patients suffering from severe arterial occlusive disease
Authors: Bongard O. , Krahenbuhl B. 
Published: April 2008

Summary. Pedal transcutaneous partial pressure of oxygen (tcPo2) has been measured by polarographic method, heating the skin at 44°C. In 50 normal subjects, mean tcPo2 measured 54 · 5 ± 7 mmHg. Among 43 patients suffering from chronic ischaemia of lower limbs, mean tcPo3 measured 40·8±8 mmHg in patients with from claudication and 16·1±15 mmHg in patients suffering from rest pain and/or gangrene. The variability of repeated tcPo2 measurements, expressed as 1 SD of the mean, was 4·5 mmHg in normal subjects and 2·9 mmHg in patients.The relationships between pedal subcutaneous blood flow measured in xenon‐133 clearance method and pedal tcPo2 have been studied in nine normal subjects and in five patients suffering from severe chronic ischaemia of lower limbs (rest pain and/or gangrene). There was a positive correlation between blood flow and tcPo, in normal subjects (r=0·77, P< 0·001). In patients suffering from severe ischaemia, there was no correlation between these two parameters, but measured blood flow was sometimes very high in areas where tcPo2 was low. It is likely that 133Xe clearance method considerably overestimates local blood flow in these patients, because there is considerably less fat in subcutaneous tissue of chronic severely ischaemic areas. Thus, partition coefficient should be determined in each patient. However, tcPo2 may constitute an index of nutritional circulation, while 133Xe clearance actually measures total subcutaneous blood flow.
The relative isometric strength of type I and type II muscle fibres in the human quadriceps
Authors: Young Archie 
Published: April 2008

Summary. In isometric contractions, the type II fibres of animal muscle may have a greater specific strength than the type I fibres. This paper reports two retrospective analyses of the influence of fibre‐type composition on the ratio of the voluntary isometric strength of the quadriceps to its cross‐sectional area at mid‐thigh.In 15 normal quadriceps, the ratio of the muscle's strength to its cross‐sectional area was weakly correlated with the percentage contribution of type II fibres to a biopsy from the lateral mass of the muscle (r = 0·55, P<0·05). Linear regression suggested that type II fibres might have about three times the specific strength of type I fibres.Measurements of the atrophied quadriceps of 11 patients with unilateral knee injury/immobilization were standardized by comparison with the contralateral muscles. Strength/cross‐sectional area was again correlated with the percentage area as type II fibres (r = 0·62, P<0·05). The data suggested that type II fibres might have about twice the specific strength of type I fibres.Despite the wide confidence limits of each of the analyses, they agree that, in isometric contractions, the type II fibres of the human quadriceps seem stronger, for their cross‐sectional area, than the type I fibres.
Reflex inhibition of the quadriceps after meniscectomy: lack of association with pain
Authors: Shakespeare D. T. , Stokes M. , Sherman K. P. , Young A. 
Published: April 2008

Summary. We have examined the severity and duration of reflex inhibition of quadriceps activation after arthrotomy and meniscectomy, its relationship with pain, and the effect of local anaesthesia on this relationship.Fourteen men, on completion of medial meniscectomy by arthrotomy, received either 10 ml (BIO group) or 15 ml (B15 group) of 0–5% bupivacaine hydrochloride (‘Marcaine Plain’) into the knee, or no injection (control group). Reflex inhibition of quadriceps was measured as the percentage reduction, from the ipsilateral preoperative value, in the integrated surface electromyogram recorded during maximal voluntary isometric contractions with the knee in extension. Pain during each contraction was recorded on a linear analogue scale.Unoperated limbs showed no evidence of quadriceps inhibition. In the operated limbs, at 1–2 h post‐operatively, controls had both severe inhibition (median = 62%) and severe pain on attempting a maximal quadriceps contraction. The BIO group had similar inhibition but less pain (P= s 0–005, Wilcoxon 2‐sample, 1‐tailed test). In the B15 group both inhibition (P 0–05) and pain (P 0–01) were less than in the controls. These effects of bupivacaine had been lost by 4–5 h post‐operatively.At 3–4 days, inhibition was still severe (median=75%) in all three groups of patients but pain was only mild or absent. At 10–15 days, median inhibition was still 35%, but there was little or no pain.We conclude that postmeniscectomy inhibition is not simply due to perceived pain but is due, at least in part, to stimuli from the knee.
Haemodynamic effects of low and high doses of insulin during beta receptor blockade in dogs
Authors: Reikerås Olav , Gunnes Pål , Sørlie Dag , Ekroth Rolf , Jorde Rolf , Mjøs Ole Danbolt 
Published: April 2008

Summary. Haemodynamic effects of small and high doses of insulin during beta receptor blockade were studied in nine dogs. Beta receptor blockade was induced by 0.5 mg/kg propranolol and caused depression of cardiac performance with a significant increase in left ventricular end‐diastolic pressure (LVEDP) and a significant decrease in heart rate; maximum rate of left ventricular (LV) pressure rise (LVdP/dtmax), stroke volume and cardiac output. At 15 min, after beta receptor blockade, a bolus injection of 0.5 IU/kg of insulin, free of glucagon and calcium, was given followed by a continuous infusion of 0.5 IU/kg/h. After 30 min another bolus dose of 300 IU insulin was injected.Glucose and potassium were given to maintain physiological levels of these factors. Five minutes after a low dose of insulin there was a significant decrease in LVEDP (P<0.01), and a significant increase in LVdP/dtmax (P<0.01), in stroke volume (P<0.01) and in cardiac output (P<0.01). The other haemodynamic variables were not significantly changed. Administration of a high dose of insulin further, significantly, improved performance of the beta receptor blocked heart and caused a significant reduction in total peripheral resistance. In conclusion, insulin exerts inotropic and vasodilator effects which are dose‐dependent and not related to adrenergic mechanisms.
Effect of adrenaline on exchange of glucose in leg tissues and splanchnic area. A comparison with the metabolic response to surgical stress
Authors: HåRkanson E. , Rutberg H. , Jorfeldt L. 
Published: April 2008

Summary. Surgical trauma is accompanied by increased energy expenditure and raised arterial concentrations of adrenaline and glucose. In order to study the acute effects of an adrenaline infusion on glucose metabolism and oxygen uptake in the leg and splanchnic bed, adrenaline was administered at a rate giving plasma concentrations of adrenaline similar to those in connection with abdominal surgery.Seven healthy males participated in the study. Adrenaline 40 ng/(min×kg body weight) (0·22 nmol/(min×kg body weight)) was infused producing a plasma concentration of 2–77±0·42 nmol/1 (mean±SEM). Leg and splanchnic blood flows and the femoral and hepatic arterio‐venous differences for oxygen, glucose, lactate and other metabolites were determined. Measurements were made before and between 30 and 40 min after the start of the adrenaline infusion.Following the infusion of adrenaline the leg blood flow increased by 140% and hepatic blood flow by 25%. The leg oxygen uptake increased by 30%, but no significant increase in splanchnic oxygen uptake was observed. The arterial glucose concentration rose by 35%. Splanchnic glucose output increased × 2·5, but no significant increase in leg glucose uptake was observed. Leg release of gluconeogenic substrates increased but only lactate and glycerol uptake increased in the splanchnic bed. Leg blood flow increased more than that usually seen after surgery, whereas leg oxygen uptake and splanchnic oxygen uptake was higher in the immediate postoperative period. Splanchnic glucose release increased more during the infusion than in connection with surgery.It is concluded that adrenaline at a plasma concentration similar to that during and immediately after surgery can induce changes in glucose metabolism which are of the same order or more pronounced than those seen in connection with abdominal surgery.
Indocyanine green plasma clearance as a measure of changes in hepatic blood flow
Authors: Kanstrup I.‐L. , Winkler K. 
Published: April 2008

Summary. The results from simultaneous measurements of indocyanine green (ICG) plasma clearance and hepatic blood flow (HBF) in subjects without hepatic dysfunction duringchanges in HBF induced pharmacologically or by food stimulation, are reported.A linear relation is established between the relative changes in HBF and that of ICG clearance (r= 0·94), but the changes are not identical, and therefore the changes in HBF cannot be accurately predicted from that of ICG plasma clearance. The reason behind the lack of identity of the changes lies in the complicated kinetics of dye removal by the liver. The hepatic venous catheterization technique is the only method when physiologically correct values for hepatic blood flow or changes therein are wanted.
Improved working capacity following theophylline infusion in patients with ischaemic heart disease
Authors: Edlund A. , Söderberg R. , Henriksson P. 
Published: April 2008

Summary. The effect of theophylline on the working capacity of patients with ischaemic heart disease was evaluated in a double‐blind, randomized cross‐over study. Eight patients, receiving no medication, with stable effort‐provoked angina pectoris and typical exercise‐induced ST depressions were studied. Following intravenous administration of theophylline or placebo, the patients did a supine leg exercise limited by intolerable chest pain. The workload was continuously increased by 10 W/min. Following theophylline treatment the workload at the onset of chest pain increased from 71 ± 9 to 114 ± 14 W (P< 0·002). The ST depression was less pronounced following theophylline at submaximal exercise (‐0·01 ± 0·00 vs. ‐0·09 ± 0·02 mV, P< 0·005, at 70 W). The maximum tolerable workload increased from 129 ± 15 after placebo infusion to 153 ± 12 W after theophylline infusion P<0·01).It is speculated that this beneficial effect of the adenosine receptor antagonist theophylline may possibly be due to inhibition of a pathophysiological coronary steal induced by elevated levels of adenosine during ischaemia.
Excretion of thromboxane A2 and prostacyclin metabolites during treadmill exercise in patients with intermittent claudication
Authors: Wennmalm Å. , Edlund A. , Sevastik B. , FitzGerald G. A. 
Published: April 2008

SummaryPlatelet activation, with subsequent formation of thromboxane A2 (TxA2), is thought to play a role in the development of arterial occlusion. In patients with severe atherosclerosis of the lower limbs, characterized by leg ulcers and rest pain, the basal formation of TxA2 and prostacyclin (PGI2) is increased. Corresponding data in patients with more moderate atherosclerosis of the lower limbs have not been reported. Since the capacity to physical exercise is not blunted in such patients proper evaluation of their TxA2‐PGI2 synthesis should comprise not only assessment of the basal formation, but also TxA2/PGI2 biosynthesis during conditions of elevated cardiovascular activity. To address this, we analysed these eicosanoids in patients with a history of intermittent claudication. Urinary dinormetabolites of TxB2 and PGI2 (Tx‐M and PGI‐M, respectively) were estimated by gas chromatography/negative ion‐chemical ionization mass spectrometry in samples collected prior to, during and immediately after 20 min of severe treadmill exertion. The basal excretion of Tx‐M was 105 ± 26 pg/mg creatinine. It was not changed during exercise, but increased to 176 ± 48 pg/mg creatinine (P<0·05) during the recovery. The basal excretion of PGI‐M was 142 ± 25 pg/mg creatinine. The PGI‐M response to exercise varied from no change at all to a 30‐fold increase, without any obvious correlation to experienced leg pain, walking distance or other recorded variables. During the recovery period the outflow of PGI‐M was significantly higher than at rest (482 ± 145 pg/mg creatinine; P<0·01).We conclude that in patients with intermittent claudication due to atherosclerosis (1) platelet activation does not occur during the course of the exercise, and (2) vascular prostacyclin formation can be dissociated from of TxA2 synthesis. The observed increase in PGI‐M in some of the patients is suggested to reflect tissue ischaemia induced by the lack of adequate hyperaemia during exercise.
Muscular venous blood metabolites during rhythmic forearm exercise while breathing air or normoxic helium and argon gas mixtures
Authors: Douguet D. , Raynaud J. , Capderou A. , Pánnier C. , Reiss G. , Durand J. 
Published: April 2008

Summary. The effects of breathing normoxic helium or argon gas mixture on the local muscular metabolism during exercise were compared to those of room air in four healthy subjects. For this purpose, Po2, Pco2, pH, the concentrations of lactate (LA), glucose (Gl) haemoglobin (Hb) and K+ and osmolarity were repeatedly measured in efferent muscular venous blood during 12 min of rhythmic forearm exercise and 16 min of recovery.The time courses and magnitude of the changes in Pco2, pH, [Gl], [Hb], [K+] and osmolarity during exercise and recovery were similar for breathing both the helium and argon gas mixtures.The main finding was that during exercise, the [LA] curve reached a peak value significantly higher by 25% under normoxic helium than under room air or normoxic argon breathing. This rise in [LA] was accompanied by a slight reduction in muscular venous Po2, too small to signify muscular hypoxia. The possibility that this decline in Po2 might be due to a shift in muscular metabolism towards lipid oxidation was confirmed by the lower muscular respiratory quotient observed during helium breathing. However, such a shift did not explain why [LA] rose during this breathing. The probable explanation is that helium facilitates LA diffusion out of the myocytes.
Diagnostic value of longterm ambulatory ECG in patients with syncope, dizziness or palpitations
Authors: Ringqvist I. , Jonason T. , Nilsson G. , Khan A. R. 
Published: April 2008

Summary.The diagnostic value of longterm ambulatory ECG recording (LTER) was determined in 63 patients referred for investigation of syncope, in 32 with dizziness and in 89 with palpitations.Among patients referred for syncope, dizziness or palpitations 8, 13 and 54%, respectively, had typical symptoms during the recording with concomitant arrhythmia explaining the symptom, and 6, 50 and 11% had a typical symptom without concomitant arrhythmia. In 12 and 3% of the patients referred for syncope or dizziness, respectively, arrhythmia was observed and probably explained their previous complaint, but no symptoms occurred during LTER.LTER was found to be of diagnostic value in 24% of the patients with syncope, in 66% of those with dizziness and in 65% of those with palpitations. In the latter two groups the presence of symptoms the week before the start of these recordings predicted the occurrence of symptoms during LTER. Only occasionally was there a higher yield of typical symptoms beyond 48 h of recording.
Limitation of finger systolic pressure measurement as a diagnostic test for primary Raynaud's phenomenon in a female population
Authors: Leppert J. 
Published: April 2008

Summary. The diagnostic value of measurement of the finger systolic pressure (FSP) was assessed during combined local and whole body cooling in a population‐based sample of women with a medical history of primary Raynaud's phenomenon. Forty women had mild Raynaud's phenomenon and 40 had pronounced Raynaud's phenomenon. The results were compared with subjective assessments of complaints from Raynaud's phenomenon as indicated on a visual analogue scale (VAS) in the same group of women.The mean FSP at 10°C was significantly lower in the patients than in 24 age‐ and sex‐matched controls, but there was a large overlap in individual responses. The sensitivity of the FSP method was only 51% for the whole group with primary Raynaud's phenomenon. There was no significant difference in FSP at 10°C between subjects with mild and those with pronounced Raynaud's phenomenon. The subjective severity of the symptoms as indicated on VAS was significantly higher in these two combined groups than in the controls. The mean VAS value was significantly higher in the group with pronounced Raynaud's phenomenon (P<0·01) than in that with the mild type.The low sensitivity of FSP measurement implies that this method is of limited value as a diagnostic test in subjects with primary Raynaud's phenomenon. Furthermore, there was no significant correlation between FSP and the VAS values (r= 0·23).
Meal‐induced thermogenesis in obese patients before and after weight reduction
Authors: Thörne A. , Hallberg D. , Wahren J. 
Published: April 2008

Summary. The purpose of this study was to find out whether human obesity is associated with a diminished meal‐induced thermogenesis and, if so, to what extent this response is influenced by weight reduction. Ten obese subjects (body mass index 42 ± 2) and 10 age‐ and sex‐matched non‐obese volunteers were studied with continuous indirect calorimetry in the basal state and after the ingestion of a standardized test meal. Six obese subjects (body mass index 44 ± 2) were examined on two occasions, once before and once after gastric banding and an average weight reduction of 18 ± 3 kg. Basal oxygen uptake and energy expenditure were 30% (P<0·001) greater in the obese subjects compared to non‐obese controls. After the meal, pulmonary oxygen uptake and energy expenditure increased rapidly and reached a relatively constant level after 60 min; for pulmonary oxygen uptake the average rise above basal was less in the obese (17·7 ± 1·6%) than the non‐obese (27·8 ± 1·9%, P<0·001); the increase in energy expenditure was 18·5 ± 1·7% in obese and 30·8 ± 2·1% in non‐obese subjects (P<0·001). After weight reduction, oxygen uptake and energy expenditure in the basal state were 20% lower (P<0·05) than before weight reduction. The average postprandial increase in oxygen uptake was greater after weight reduction (24·8 ± 2·0%) than before (16·7 ± 1·6%, P<0·001). Corresponding values for energy expenditure were 27·2 ± 2·2 and 18·2 ± 2·2% (P<0·001).It is concluded that:(1) the thermogenic response to a mixed meal is lower in obese compared to non‐obese individuals; and,(2) this impaired response is partly normalized after weight reduction.These findings suggest that a diminished meal‐induced thermogenesis is a secondary phenomenon rather than a primary pathogenic factor in human obesity.
Evaluation of a dynamometer measuring torque of uni‐ and bilateral concentric and eccentric muscle action
Authors: Tesch P. A. , Lindborg B. P. O. , Colliander E. B. 
Published: April 2008

Summary. A dynamometer designed for torque measurements of uni‐ and bilateral concentric and eccentric muscle actions of the quadriceps and hamstring muscle groups is described.Torque reproducibility and control of lever‐arm position were studied using known standards. In vivo measurements assessed angular velocity, lever‐arm acceleration, variability of torque between limbs and reproducibility of torque.Torque obtained from left and right leg attachments was equal when using weights and during dynamic in vivo conditions. Static torque recorded at different lever‐arm positions and known torque were equal. Likewise, lever‐arm position output equated with known angles. In vivo test‐retest of peak torque was found to be reliable. Acceleration of the lever arm was greater for concentric bilateral than for unilateral muscle actions but equal during eccentric muscle actions.The dynamometer is suggested to provide valid and reproducible torque measurements up to at least 700 Nm at constant angular velocities up to 2·62 rad s‐1. Besides being a research tool the dynamometer is useful in clinical settings for rehabilitation and evaluation of skeletal muscle function.
Plasma lipolytic activity and substrate oxidation after intravenous administration of heparin and a low molecular weight heparin fragment
Authors: Persson E. , Nordenström J. , Nilsson‐Ehle P. , Hagenfeldt L. , Wahren J. 
Published: April 2008

Summary. This study examines the effects of heparin and a low molecular weight heparin (LMWH) fragment on plasma lipolytic activity and substrate oxidation. Indirect calorimetry was performed continuously in healthy male subjects receiving a constant infusion of fat emulsion (0·2 g min‐1) and glucose (0·8 g min‐1) during a period of 4 h. After 2 h an infusion of heparin (n= 6) or LMWH (n= 6) (100 antifactor Xa units kg‐1) or saline (n= 6) was given over 1 h.Plasma concentration of the fat emulsion decreased by 76 ± 5% with heparin and by 12 ± 7% with LMWH (P<0·01). In the case of LMWH the initial fall was followed by a consistent rise in fat emulsion concentration for the entire remaining study period. Compared to the control experiments, plasma FFA increased five times with heparin and three times with LMWH (P<0·05). The average respiratory quotient (RQ) and energy expenditure (EE) increased constantly during the study period and did not differ significantly between the groups. In all groups the average increase in glucose oxidation was 40–50%, while fat oxidation decreased to a comparable extent. Infusions of heparin and LMWH had no effect on RQ or EE. A microcalorimetric study on isolated rat adipocytes in buffer solutions containing glucose, fat emulsion, heparin or LMWH was also made. The heat output from the adipocytes was not influenced by the presence of heparin or LMWH.In conclusion, infusion of heparin resulted in a pronounced increase in FFA availability, whereas LMWH exerted a less marked lipolytic effect. However, the heparin‐induced elevations in plasma FFA were not accompanied by measurable rises in lipid oxidation rate.