bluuebunny/crossref_metadata_2025 huggingface dataset:
Free amino acids in plasma and muscle during 24 hours post‐operatively – a descriptive study
Authors: Essen P. , Wernerman J. , Sonnenfeld T. , Thunell S. , Vinnars E.
Published: April 2008

Summary. Intracellular amino acids in skeletal muscle show a specific concentration pattern on the third post‐operative day. The temporal development of these changes has not been clarified. Here the amino acid concentrations in skeletal muscle were studied during the first post‐operative day in fourteen patients undergoing elective abdominal surgery. Muscle amino acids were determined pre‐operatively, as well as at 12 and 24 h post‐operatively. In muscle the concentrations of glutamine and the basic amino acids decreased gradually during the first 24 h after surgery to 79% (P< 0 001) and 67% (P< 001) respectively. The sum of the essential amino acids decreased to 73% (P<0 001) at 12 h, but thereafter rose to 91% (P<0 05) at 24 h. The sum of the BCAA decreased to 84% (P<0.05) at 12 h but then increased to 116% (P<0 05) at 24 h. The alanine concentration increased to 122% (P<0 001) during the first postoperative day. In plasma the alanine concentration increased at 12 h while most other amino acids declined. At 24 h post‐operatively the plasma concentrations of all amino acids had returned to normal or showed a tendency towards normalization except for phenylalanine, which increased. At the end of the first post‐operative day the concentrations of amino acids in muscle were consistent with the alterations previously observed three days after surgery. The changes in plasma amino acid concentrations only partly reflected those in muscle.
Cardiovascular reflex tests and the resting heart rate at night and during testing
Authors: Piha S. J.
Published: April 2008

Summary. Possible effects of environmental stress‐induced elevation of the heart rate on the magnitude of cardiovascular autonomic responses were studied in 123 healthy subjects. The nocturnal heart rate was evaluated using ambulatory 24‐h ECG monitoring. Some of the cardiovascular responses were found to be significantly weaker in those subjects whose resting heart rate during testing was >10 beats min‐1 higher than the resting nocturnal heart rate. It is thus highly important to minimize the environmental disturbances during autonomic testing.
Early exercise thallium‐201 single photon emission computed tomography in unstable angina: a prospective study
Authors: Amanullah A. , Bevegård S. , Lindvallf K. , Herlitz E.
Published: April 2008

Summary.To evaluate the safety and diagnostic value of early symptom‐limited exercise electrocardiography (ECG) and exercise thallium‐201 single photon emission computed tomography (SPECT) in unstable angina (UA), 39 patients were studied prospectively soon after stabilization on medical treatment. No patient had a history of myocardial infarction (MI) or revascularization and patients with left bundle branch block were excluded. Exercise ECG and exercise thallium‐201 SPECT were performed 8 plusmn; 4 days and 11 plusmn; 6 days respectively after admission to hospital. Seventeen out of 39 patients (44%) had positive exercise ECGs and 22 (56%) negative or inconclusive ones. Exercise thallium‐201 SPECT was positive in 26 patients (67%) and negative in 13 patients (33%). Thirty‐one patients underwent coronary arteriography and 24 of them proved to have significant coronary artery disease (CAD). The sensitivity, specificity and positive predictive value of exercise ECG in detecting CAD are 62%, 86%, and 94% respectively while the corresponding results are 96%, 100%, and 100% for exercise thallium‐201 SPECT. Therefore, it is concluded that the early symptom‐limited exercise test is safe in medically stabilized patients with UA. Early exercise thallium‐201 SPECT is highly sensitive and predictive of the presence of significant CAD among patients in the early recovery phase of UA and can be used in selecting this group of patients for coronary angiography and other therapeutic strategies.
Use of non‐invasive finger blood pressure monitoring in the estimation of aortic pressure at rest and during the Mueller manoeuvre
Authors: Virolainen J.
Published: April 2008

Summary. The aim of this investigation was to evaluate whether reliable estimates of aortic pressure can be derived using non‐invasive finger blood pressure monitoring. Finger blood pressure (Ohmeda 2300 Finapres device; Finapres, Englewood, CO) was compared with simultaneous ascending aortic pressure measured with a catheter‐transducer system both at rest and during acute negative intrathoracic pressure (the Mueller manoeuvre). Thirty‐eight patients aged 17–73 years were studied. All were undergoing routine diagnostic or therapeutic cardiac catheterization.

Beat‐to‐beat values of systolic, diastolic and mean non‐invasive finger and invasive aortic blood pressure were measured at rest and factors which might have an influence on the difference between methods were examined. The mean finger‐aortic difference was +5 ± 14 mmHg for systolic, ‐2 ± 7 mmHg for diastolic, ‐5 ± 8 mmHg for mean and +6 ± 13 mmHg for pulse pressure. In multivariate linear regression analysis, the difference in systolic pressure was related to aortic systolic pressure (standardized coefficient β=‐0.33, P= 0.01), heart rate (β= 0.49, P<0.000), age (β=‐0.29, P<0.025) and height (β= 0.40, P<0.005). The linear regression equations to derive resting aortic pressures from the non‐invasive finger pressure readings had correlation coefficients between 0.83 and 0.87 and standard errors of estimate between 6 and 14 mmHg. During the Mueller manoeuvre, Finapres reproduced average pressure changes reliably compared with intra‐aortic pressure. Due to moderate inter‐individual variation in the finger‐aortic differences the correlation coefficients ranged from 0.83 to 0.93 and the standard errors of estimate from 3 to 6 mmHg.

Non‐invasive finger blood pressure monitoring could be used to estimate central aortic mean and diastolic blood pressure fairly reliably at rest, but with respect to systolic pressure the variance in finger‐aortic difference was marked. The average intra‐aortic pressure changes caused by the Mueller manoeuvre were reliably reproduced by the Finapres device.
Relationship between hyperglycaemia and aerobic power in men with newly diagnosed type 2 (non insulin‐dependent) diabetes
Authors: Vanninen E. , Uusitupa M. , Remes J. , Siitonen O. , Laitinen J. , Länsimies E. , Pyörälä K.
Published: April 2008

Summary.The aim of the study described here was to evaluate aerobic function during exercise and its determinants in middle‐aged men with newly diagnosed Type 2 (non insulin‐dependent) diabetes. Using breath‐by‐breath technique, we measured O2uptake at anaerobic (ventilatory) threshold and at peak exercise in a group of diabetic men (n= 19; fasting blood glucose 8.6 ± 0.7 mmol l‐1, mean ± SEM) without any disease or medication that could have had an influence on exercise performance, and compared the results to those observed in non‐diabetic healthy control men (n= 18). There were no differences in physical activity or smoking habits between the groups. Oxygen uptake was lower in the diabetic men than in the control men both at anaerobic threshold (15.0 ± 0.8 vs. 18.8 ± 1.0 ml min‐1kg‐1,P<0.01) and at peak exercise (25.3 ± 1.5 vs. 31.1 ± 1.4 ml min‐1kg‐1,P<0.01). In the diabetic men peak O2uptake showed an inverse linear correlation with age (r= ‐0.71,P≤0.001), fasting blood glucose (r= ‐0.49,P<0.05) and glucose response in an oral glucose tolerance test (r=‐0.43,P<0.05). In addition, long‐term smoking was associated with impaired peak O2uptake. In a stepwise multiple regression procedure 75% of the total variance of peak O2uptake in the diabetic men was explained by age, post‐load blood glucose response and smoking history. Thus, in addition to ageing and smoking, hyperglycaemia is correlated with impaired aerobic power in men with newly diagnosed Type 2 diabetes.
Short‐term starvation decreases skeletal muscle protein synthesis rate in man
Authors: Essén P. , McNurlan M. A. , Wernerman J. , Milne E. , Vinnars E. , Garlick P. J.
Published: April 2008

Summary The rate of protein synthesis in skeletal muscle was determined in the post‐absorptive state and after 3 days of starvation in healthy volunteers. The flooding dose technique employing intravenous injection of (1‐13C)leucine (0.05 g kg‐1) was used and incorporation of isotope into muscle protein was measured by taking percutaneous biopsies at 0 and 90 min. Blood samples were taken during the incorporation period for assessment of the enrichment of the free amino acid precursor of protein synthesis. The median (25,75 quartiles) rate of muscle protein synthesis after an overnight fast was 2.03 (2.00,2.23) % days‐1 when the precursor enrichment was obtained by measurement of the plasma α‐ketoisocaproate, taken to be representative of muscle free leucine. Repeat measurements in the same subjects after 3 days of total starvation showed a decrease to 1.82 (1.57,2.05) % days‐1. Rates calculated on the basis of the plasma leucine as precursor were 5% lower at both times. An interindividual variation in response to starvation was observed, but the median decrease of 13% in the rate of protein synthesis was statistically significant (P<0.01).
High anaerobic energy release during submaximal arm exercise
Authors: Jensen‐Urstad M. , Hallbäck I. , Sahlin K.
Published: April 2008

Summary. The anaerobic energy release during submaximal arm (AE) and leg exercise (LE) has been estimated from O2 deficit measured at the onset of exercise. Eight male subjects were studied during 8–10 min of arm or leg cycling at the same relative workload (53% of the peak exercise‐induced increase in pulmonary oxygen uptake, VO2). The workloads were 78 ± 4 W during AE and 173 ± 11 W during LE and Vo2 was 1.51 ± 006 1 min‐1 for AE and 2.33 ±0.15 1 min‐1 for LE. The half‐time of the Vo2 on‐response was considerably longer (P<0.01) during AE (62 ± 9 s) than during LE (33 ± 4 s) and the peak blood lactate concentration was higher (P<0.05) during AE (4.8 ± 0.5 mmol‐l‐1) than during LE (3.5 ±0.4 mmol‐l‐1). Oxygen deficil was 1.64 ±016 and 1.78 ±0.16 1 for AE and LE respectively. Oxygen deficit was higher during AE than during LE when related to absolute workload (P<0.01), or tc Vo2 at steady state (P<0.001) or to limb volume (P<0.001). The proportion of the total energy demand covered by anaerobic energy release at the onset of exercise (0–8 min) was about 54% higher (P<0.01) during AE than during LE. It is concluded thai the energy release to a greater extend is covered by anaerobic processes during AE than during LE.
Work capacity and metabolic and morphologic characteristics of the human quadriceps muscle in response to unloading
Authors: Berg H. E. , Dudley G. A. , Hather B. , Tesch P. A.
Published: April 2008

Summary. The response of skeletal muscle to unweighting was studied in six healthy males who were subjected to four weeks of lowerlimb suspension. They performed three bouts of 30 consecutive maximal concentric knee extensions, before unloading and the day after (POST 1), 4 days after (POST 2) and 7 weeks after (REC) resumed weight‐bearing. Peak torque of each contraction was recorded and work was calculated as the mean of the average peak torque for the three bouts and fatigability was measured as the decline in average peak torque over bouts. Needle biopsies were obtained from m. vastus lateralis of each limb before and at POST 1. Muscle fibre type composition and area, capillarity and the enzyme activities of citrate synthase (CS) and phosphofructo‐kinase (PFK) were subsequently analysed. Mean average peak torque for the three bouts at POST 1, POST2 and REC was reduced (P < 0.05) by 17,13 and 7%, respectively. Fatigability was greater (P < 0.05) at POST 2 than before unloading. Type I, HA and IIB percentage, Type I and II area and capillaries per fibre of Type I and II did not change (P > 005) in response to unloading. The activity of CS, but not PFK, decreased (P < 0.5) after unloading. The weight‐bearing limb showed no changes in the variables measured. The results of this study suggest that this human lowerlimb suspension model produces substantial impairments of work and oxidative capacity of skeletal muscle. The performance decrements are most likely induced by lack of weight‐bearing.
Renal effects of i.v. adenosine infusion in humans
Authors: Edlund A. , Sollevi A.
Published: April 2008

Summary. The effects of systemic intravenous (i.v.) infusion of adenosine on renal blood flow and glomerular filtration in eight healthy, awake females have been examined.

In conclusion, i.v. infusion of adenosine in healthy, awake subjects causes a minor increase in total renal blood flow and a marked reduction in glomerular filtration. This shows that adenosine also exerts a vasodilatory effect in the renal circulation, primarily on postglomerular arterioles. In addition, adenosine may produce an aldosterone‐like effect on salt excretion, and a reduction in renal oxygen consumption.

Renal blood flow and glomerular filtration rate were measured as the clearance of para‐aminohippuric acid (PAH) and inulin, respectively. Following basal sampling adenosine was infused i.v. at successive rates of 60 and 80 μg kg‐1 min‐1 for 30 min at each rate.

Plasma clearance of PAH showed a minor, but non‐significant, increase from 697 ±41 to 775 ±97 ml min‐1. However, the arterial plasma concentration of PAH decreased by 17±4% (P < 00.1), indicating that there was a small increase in renal blood flow. Inulin clearance was reduced from 123±14 to 88±11 ml min‐1 1.73 m‐2 (P < 0.01). The resulting filtration fraction was reduced from 18±1 to 11±1 (P < 0.001). The K+/Na+ excretion ratio increased from a basal value of 10±1 to 42±11 (P < 0.01) at the highest dose of adenosine, and renal oxygen consumption decreased from 17±2 to 9± 1 ml min‐x (P <0.001).
Regional differences of atrial natriuretic factors in humans
Authors: Thaulow I. Os E. , Westheim A.
Published: April 2008

Summary. During sinus coronarius catheterization in humans undergoing diagnostic right‐sided cardiac catheterization, levels of atrial natriuretic factor (ANF) measured in sinus coronarius (n= 12) were four times higher than in peripheral arterial blood. Atrial natriuretic factor underwent average extractions of 0.57, 0.40, and 0.28 in the kidneys (n= 14), liver (n= 15), and forearm (n= 15) respectively. However, a close relationship was observed between arterial and peripheral venous concentrations. The substantial clearance of ANF even over the forearm indicates that arterial sampling may be preferred in conditions with altered peripheral vascular resistance, since an uptake of ANF in the peripheral vascular bed is likely to have occurred.
Reproducibility of cardiac volume measurements including left ventricular mass determined by MRI,
Authors: Møgelvang J. , Lindvig K. , Søndergaard L. , Saunamäki K. , Henriksen O.
Published: April 2008

Summary. Cardiac volumes including left ventricular mass were determined by magnetic resonance imaging (MRI) in 30 patients using a contiguous multislice technique. Eleven patients were studied on two different days. Intra‐ as well as interobserver and interstudy variation were evaluated. For volume measurements the standard deviation of differences (SDD) was rather constant, independent of the size of the measured volume indicating lower percentual variability in measuring large volumes. Lowest variability was noticed for left ventricular myocardial mass estimates between observers as well as between studies. In 13 patients left ventricular mass was estimated by this technique as well as by a method using only one long axis and four short axis slices and by two‐dimensional echocardiography. Although highly correlated, limits of agreement between the methods were too wide to accept interchangeable clinical use of the methods.
Factors affecting the validity of the standard blood pressure cuff,
Authors: Stolt M. , Sjönell G. , Åström H. , Hansson L.
Published: April 2008

Summary. Fifty‐eight patients, 31 women and 27 men, with a wide range of upper arm circumferences (20.43 cm), ages (16.82 years) and body mass indices (16.55 kg m˜2) were studied. The direct blood pressure was measured in the brachial artery in one arm and simultaneously the indirect pressure was measured in the other arm using a large standard cuff (rubber bag 12 times 35 cm).

The mean intra‐arterial blood pressure was (systolic/diastolic) 13725 mmHg (SD)/7610 mmHg. With the cuff the mean blood pressure was 13423 mmHg/85ll mmHg.

The cuff significantly underestimated the systolic blood pressure (3.2ll.4 mmHg, range ‐25–30 mmHg) while the diastolic pressure was overestimated significantly (8.88.5 mmHg, range ‐32.14 mmHg).

The direct/indirect blood pressure difference correlated significantly to the intraarterial systolic and diastolic pressures (systolic/diastolic; r=0.44, P= 0.0006/r=0.36, P= 0.0062), but only to the auscultatory diastolic pressure (r=‐0.02, P= 0.9/r= ‐0.45, P= 0.0004).

The direct/indirect difference correlated significantly to the arm circumference (r= ‐0.33, P= 0.01/r= ‐0.30, P= 0.02) as did the diastolic direct/indirect difference to pulse rate (r= 0.34, P= 0.009).

Age did not correlate significantly to the direct/indirect blood pressure difference in this study (r= ‐0.02, P= 0.9/r=‐0.10, P= 0.5).

It can be concluded that in addition to the ratio between the arm circumference and the width of the cuff (rubber bag), there are other sources of systematic errors of indirect blood pressure measurement, in particular pulse rate and the level of indirect blood pressure. If corrections could be made with regard to these variables, it is obvious that the reliability of the indirect method, especially when used in epidemiological contexts, would increase.
Differences in vascular effects and removal of endothelin‐1 in human lung, brain, and skeletal muscle,
Authors: Weitzberg E. , Ahlborg G. , Lundberg J. M.
Published: April 2008

Summary. To investigate the effects and elimination of endothelin‐1 in humans, an intravenous infusion of endothelin‐1 (ET‐1) (4 pmol kg‐1 min‐1 for 20 min) was given to 10 healthy volunteers. Arterial plasma endothelin‐1 like immunoreactivity (ET‐1‐LI) increased eleven‐fold. The fractional extraction of ET‐l‐LI was 41% and 30% across the pulmonary and skeletal muscle vascular beds, respectively. The lung eliminated almost half of the administered ET‐1. No fractional extraction was found in the cerebral circulation. The pulmonary oxygen uptake (VO2)was increased slightly by endothelin‐1. Across both the cerebral and skeletal muscle vascular beds the arterio‐venous oxygen difference decreased (P < 0–05), suggesting vasodilation, the effect lasting up to 1 h after the end of endothelin‐1 infusion in the cerebral circulation. Arterial‐pulmonary artery oxygen difference increased by 20%. ET‐1 infusion led to a decrease in heart rate (10%), cardiac output (14%) and stroke volume (8%) (all with P < 0'05) as well as a 7% increase in mean arterial blood pressure. Pulmonary and systemic vascular resistance increased by 67% and 25%, respectively (P < 0–05). These results demonstrate the regional differences in the removal of circulating endothelin‐1, the lung being mainly responsible for the plasma elimination. Endothelin‐1 seems to exert both vasoconstrictive and vasodi‐latory actions in humans, probably depending on differences in receptor populations and endothelium configuration in various vascular beds.
Effect of vasoactive intestinal polypeptide (VIP) on pulmonary ventilation‐perfusion relationships and central haemodynamics in healthy subjects,
Authors: Soderman C. , Eriksson L. S. , Juhlin‐Dannfelt A. , Lundberg J. M. , Broman L. , Holmgren A.
Published: April 2008

Summary. Ventilation‐perfusion relationships of the lung (VA/Q) and central haemodynamics were studied in nine healthy subjects before and during 30 min of vasoactive intestinal polypeptide (VIP) infusion (20 ng kg‐min‐1). During the infusion, arterial concentrations of VIP rose from 16‐1 6‐1 to 420 110 pmol 1‐1 and noradrenaline concentrations doubled (P < 0–01). VA/Q distributions, determined by inert gas elimination technique, were significantly shifted to lower values for VA/Q with slight increases in dispersions, but arterial oxygen tension remained unchanged. Heart rate, stroke volume and cardiac output rose 27, 44 and 80% respectively (P < 0–01). Systematic arterial pressure stabilized at a slightly lower level compared to basal (base line: 93 5 mmHg, VIP: 88 6 mmHg, P < 0–05). Right atrial and pulmonary capillary wedge pressures remained unchanged during VIP infusion, while pulmonary vascular resistance and systematic vascular resistance decreased significantly, by 25% (P < 0–03) and 53% (P < 0–01), respectively. It is concluded that VIP causes: (1) alterations in ventilation‐perfusion distributions, but generates no shunt and does not cause hypoxaemia during 30 min infusion, (2) reduction of pulmonary and systemic vascular resistances and afterload reduction of the left ventricle, (3) reflex sympathoadrenal stimulation with increasing heart rate and myocardial contractility, and (4) a direct positive inotropic effect on the myocardium.
Magnetic‐resonance velocity mapping of the central circulation
Authors: Søndergaard L.
Published: April 2008

Summary. In magnetic‐resonance (MR) velocity mapping there exists a linear relationship between the velocity and signal in each element of a tomographic image. The technique can be used for quantitative measurements of linear velocities (m s_1) and flow rates (1 min‐1). By using cinematographic images the flow profile during the cardiac cycle can be determined. This allows quantification of forward flow, regurgitant volume and regurgitant fraction in cases of heart‐valve insufficiency. In valvular stenosis the transvalvular pressure gradient and valve area can be determined. Magnetic‐resonance velocity mapping may also provide information about diastolic function of left ventricular function. Together with other MR imaging techniques, velocity mapping gives an accurate assessment of the severity of aortic dissection. Recent studies indicate that MR velocity mapping provides quantification of renal blood flow, and that MR imaging may be used even for coronary angiography and measurements of coronary blood flow. Therefore MR velocity mapping has the potential to become an important clinical tool for examination of the cardiovascular system providing high accuracy and quantitative measurements.
Cerebral vasodilation capacity: acute intracranial hypertension and supra‐ and infra‐tentorial artery velocity recording
Authors: de Bray J. M. , Tranquart F. , Saumet J. L. , Berson M. , Pourcelot L.
Published: April 2008

Summary. This experiment is the first to compare cerebral vasomotor reactivity in the supra‐ and infra‐tentorial regions in baseline conditions and during progressive acute intracranial hypertension. The increase in intracranial pressure was performed using liquid pressure transmission in two groups of 16 rabbits by elevating a saline infusion bottle connected to the subdural space. Cerebral microvessel dilation capacity was studied using acetazolamide arterial infusion during three stages of 20 min: at baseline conditions, with an intracranial pressure value equal to half the diastolic arterial pressure and with an intracranial pressure equal to the diastolic arterial pressure. The effects of acetazolamide in the basilar artery and in the carotid siphon were simultaneously monitored by transcranial Doppler sonography during all the experiments.

The changes in cerebral vasomotor reactivity occurred with the same intensity and latency in both vascular compartments in baseline conditions. The maximum amplitude of changes happened 30 s later in the basilar artery than in the carotid siphon. When intracranial pressure was above half the diastolic arterial pressure, the vasomotor tone began to decrease in the carotid siphon which supplies a small region of the rabbit brain, whereas it was maintained in the basilar artery. This effect could be explained by brain tissue hypertension. Vasomotor reactivity had nearly disappeared in all the cerebral arteries investigated when intracranial hypertension was equal to the diastolic arterial pressure.

These results show evidence of a direct and late effect of acute elevation of intracranial pressure on cerebral microvascular tone. This begins in the supra‐tentorial region but there is an early local effect on the carotid siphon due to the brain tissue pressure.
Modification and validation of a commercially available portable detector for measurement of adipose tissue blood flow
Authors: Samra J. S. , Frayn K. N. , Giddings J. A. , Clark M. L. , Macdonald I. A.
Published: April 2008

Summary. Adipose tissue blood flow is measured from the clearance of radioactive xenon from a depot. Traditionally, a Nal detector has been used to measure the residual depot of xenon. However, this is sensitive to movement artefacts. We tested a commercially available lightweight Csl detector which can be strapped to the anterior abdominal wall. In pilot studies the Csl detector produced higher values for adipose tissue blood flow than did a conventional Nal detector. It was modified by inclusion of spacers to distance it from the skin. Flow results generated by the modified detector were similar to those generated by the Nal detector, both after an overnight fast and during the increased blood flow after a meal. Individual decay patterns generated by the Csl detector were, however, significantly smoother than those from the Nal detector.
Fat metabolism and its response to infusion of insulin and glucose in patients with advanced chronic obstructive pulmonary disease
Authors: Jakobsson P. , Jorfeldtt L. , von Schenck H.
Published: April 2008

Summary. In order to investigate fat metabolism and the regulation of lipolysis and blood fuel metabolites by insulin, nine patients with chronic obstructive pulmonary disease (COPD) with chronic hypoxaemia and seven healthy control subjects of similar age were investigated by determination of the turnover rate of free fatty acids (TOR), using 1‐14C‐oleic acid as a tracer, and arterial concentrations of FFA, glycerol and 3‐hydroxybutyrate. The measurements were performed in the basal state and during insulin and glucose infusion, aiming at euglycaemia at insulin levels of 50 and 100 mU l‐1. The subjects' ages were 64±2.7 and 66±1.1 (mean±SEM) years in the COPD and control groups, respectively. TOR was 0.73±0.06 and 0.52±0.02 mmol min‐1 (P<0.05) in the basal state, 0.33±0.04 and 0.30±0.02 at an insulin level of 50 mU I‐1 and 0.32±0.08 and 0.24±0.02 at an insulin level of 100 mU I‐1, in the COPD and control groups, respectively. Arterial FFA concentration was 0.98±0.08 and 0.75±0.06 mmol 1‐1 (P<0.05) in the basal state in the COPD and control groups, respectively. During the clamp, the decrease in FFA mirrored that in TOR. The results show that the state of lipolysis is increased in severe COPD patients with chronic hypoxaemia. Furthermore, the results suggest a reduced effect of insulin in lipolysis.
Spirometry and ventilation‐perfusion inequality in patients with mild allergic asthma before and during the pollen season
Authors: Lagerstrand L. , Skedinger M. , Ihre E. , Halldén G. , Zetterstrom O.
Published: April 2008

Summary. Several studies on asthma have shown a low correlation between gas exchange and spirometry, especially after treatment with bronchodilators. The aim of the present study was therefore to examine both spirometry results and gas exchange during a pollen‐free period and at the end of the pollen season in patients with mild and well‐controlled allergic asthma. Pulmonary gas exchange was studied using a modified form of the multiple inert gas elimination technique. Lung volumes and forced expiratory flows were measured by common spirometry. During the non‐pollen season, spirometry and forced expiratory flows were within the reference values in all but one patient, who had decreased indices for airway flow. Three other patients showed signs of minor gas exchange impairment. During the pollen season, FRC was slightly increased (P<0.05) and MEF50 was slightly decreased (P<0.05) for the group. Two patients had an increased index for gas exchange impairment (log SDQ was 0.64 and 0.59) and four patients had borderline log SDQ (0.50 to 0.56). However, the mean log SDQ was not increased in the pollen season. The results show that, both in the pollen season and in the pollen‐free season, low degrees of gas exchange impairment could be present in pollen allergic asthmatic patients despite normal spirometry. The low degree of gas exchange impairment in some patients indicates the presence of airway inflammation with oedema and/or secretion. However, high degrees of ventilation‐perfusion inequality were not observed in these patients where air flow rates were mainly normal.
An increase in micropulmonary red cell mass in hyperlipidaemic patients
Authors: Pintarić I. , Eterović D. , Tocilj J. , Reiner Z. , Lipovac V.
Published: April 2008

Summary. It is known that pulmonary microcirculation rheology is partly affected by plasma levels of lipoproteins, but only a few data are available for humans. Therefore, in a sample of 30 normal volunteers and 90 patients with various types of primary hyperlipoproteinaemia, the plasma levels of total cholesterol (Choi), low density cholesterol (LDL), the high density cholesterol (HDL), triglyceride (Tg) and fibrinogen (Fib) were measured in conjunction with determinations of plasma viscosity (PV) and the pulmonary capillary red cell volume (RCVC). RCVC was estimated from measurements of the vascular component of the single‐breath‐diffusing lung capacity for carbon monoxide, using our own modification of the Roughton‐Forster's method. By stepwise regression analysis, the variation in RCVC was almost completely accounted for (r2=0.87) by variations in PV, Choi, Tg and the anthropometric confounding factors. The proposed explanations for increased pulmonary capillary red cell mass (up to 151 % of the predicted value) in hyperlipidaemic patients included the hypothesis of increased pulmonary microhaematocrit, which agrees with the observed in‐vitro lipoprotein‐dependent increase in erythrocyte aggregability.
Effect of 8‐day therapy with propionyl‐L‐carnitine on muscular and subcutaneous blood flow of the lower limbs in patients with peripheral arterial disease
Authors: Bolognesi M. , Amodio P. , Merkel C. , Godi L. , Gatta A.
Published: April 2008

Summary. The efficacy of propionyl‐L‐carnitine in increasing walking capacity in patients with peripheral arterial disease is primarily due to the metabolic effect of the drug, but a direct vasoactive action is also hypothesized. Muscular and subcutaneous blood flow of lower limbs were separately evaluated using the 133‐Xenon washout technique in 10 patients with peripheral arterial disease of moderate degree, before and after 8‐days of treatment with propionyl‐L‐carnitine (1 g orally b.i.d.). After treatment, muscular blood flow slightly increased, from 10.7±13.4 to 14.1±14.0 ml kg‐1 min‐1. This increase was not statistically significant (T=‐1.6568, P=0.136). Subcutaneous blood flow was not affected by the treatment (from 26.2±16.9 to 26.1±12.5 ml kg‐1 min‐1, T=0.0141, P= 0.95). In conclusion, in patients with peripheral arterial disease, short‐term therapy with propionyl‐L‐carnitine had no clinical significant effect on muscular and subcutaneous blood flow of the lower limbs. Therefore, this study suggests that the beneficial effect of this drug on the walking capacity of patients with peripheral arterial disease is not due to a direct vasoactive action. Oral administration of propionyl‐L‐carnitine was found to be safe, as it did not cause any change in hepatic, renal or metabolic functional parameters.
Limitations of R‐average as an index of left ventricular isovolumic relaxation
Authors: Myrmel T. , Krukenkamp I. B. , Caldarone C. A. , Burns P. A. , Gaudette G. , Levitsky S.
Published: April 2008

Summary. Freeman et al. (1993) have recently introduced a new index measuring isovolumic relaxation in the in situ left ventricle. This index, called the R‐average, shows less variability than the traditionally used monoexponential time constant (tau, τ), and could therefore represent an alternative measure of isovolumic relaxation during different physiological or pathophysiological interventions. However, the R‐average represents the average pressure fall during isovolumic relaxation (isovolumic pressure fall divided by the isovolumic time period), and is therefore highly influenced by the end‐systolic pressure level. The present study was done in order to assess whether small increments in loading conditions would alter the R‐average without changes in the isovolumic relaxation period or the monoexponential pressure decay T. We used a right heart bypass porcine model, and end‐systolic pressure was altered between 92 and 140 mmHg by pre‐loading (servo‐pump) or after‐loading (phenylephrine) in spontaneously beating and paced hearts. During loading, we found a significant increase in the R‐average and a close correlation (r=0.72‐0.99) between R‐average and end‐systolic pressure. However, no alterations were found in the duration of the isovolumic relaxation time period or monoexponential pressure decay (T) during these loading conditions. In our view, the R‐average indicates the systolic loading level for the ventricle, but does not necessarily reflect alterations in the process of active relaxation.
Does abnormal single‐breath nitrogen wash‐out predict an accelerated decline in FEV1 in lung‐healthy subjects?
Authors: Dahlqvist M.
Published: April 2008

Summary. Single‐breath nitrogen wash‐out and forced expirograms measured on two occasions, 8 years apart, were analysed for 24 subjects with varying degrees of peripheral airway involvement. Correlation analyses were carried out between closing volume in percentage of vital capacity (CV%), the slope of the alveolar plateau (phase III) and forced expiratory volume in 1 s (FEV1) for both occasions. The correlations between CV% and phase III measured on the first occasion and the long‐term change in FEV1 were also studied.

It is concluded that large deviations are required for CV% as well as phase III before any pathological decreases in the large airways will occur. The prognostic value of an abnormal single‐breath nitrogen wash‐out seems to be limited, at least in lung‐healthy subjects.
Pharmacokinetics and dosimetry of [111In] F(ab‘)2 fragments against prostatic acid phosphatase after intraprostatic injection for immunoscintigraphy in prostate cancer
Authors: Nielsen J. T. , Poulsen J. , Flø C. , Marqversen J. , Rehling M.
Published: April 2008

Summary. The purpose of this study was to investigate the pharmacokinetics and dosimetry of using [111In]‐labelled F(ab')2 fragments against prostate acid phosphatase (FC‐3001, Orion Corporation Farmos, Finland) for the detection of metastatic prostate cancer.

Five patients in all were subjected to intraprostatic injection of 1 mg FC‐3001 labelled with 85–100 MBq [111In]. In four of the patients the biodistribution was studied by sequential whole‐body counting, gamma‐camera scintigraphy of the abdomen in anteroposterior and postero‐anterior projections. Blood and urine samples were collected sequentially up to 72 h after injection.

Initially, significant amounts of antibody fragments were released from the site of injection. After the first 4 h, 22.0% of injected antibody (2.2–41.3%ID) remained in the prostate and was slowly released with a final half‐life of 80.4 h (49.9–141.8 h). Labelled antibody appeared in the blood shortly after injection and was cleared from the blood with a final half‐life of 27.7–300.9 h. The liver, the bone marrow and, in two patients, the kidneys accumulated antibody fragments in significant amounts during the period of investigation. An apparent relationship between the initial whole‐body clearance and renal uptake is described. The effective dose averaged 0.37 mSv/MBq (range 0.24‐0.52 mSv/MBq). The highest equivalent doses were received by the kidneys (0.46‐2.81 mGy/MBq) the liver (0.44‐1.59 mGy/MBq) and the bone marrow (0.37‐0.57 mGy MBq). Only in two of the patients with known metastases were pathological foci seen.

The disappointing imaging results were probably caused by the biphasic release of antibody from the prostate, and indicates that intraprostatic injection of this antibody has no advantage for imaging, as well as being unpleasant for the patient. The biodistribution of the antibody following release from the prostate is similar to but more variable than the biodistribution seen in patients after intravenous injection of labelled antibodies.
The velocity distribution in the aortic annulus at different times during systole is mainly determined by the pattern of flow convergence in the left ventricular outflow tract ‐ An experimental study using Doppler colour flow mapping
Authors: Zhou Y.‐Q. , Faerestrand S. , Birkeland S. , Matre K. , Koller M.‐E. , Husby P.
Published: April 2008

Summary. An experimental study in 10 open chest normal pigs (body weight: 24 ±1 kg) was carried out to explore the relationship between the velocity distribution in the aortic annulus and the pattern of flow convergence in the left ventricular outflow tract. The cross‐sectional velocity profiles in the aortic annulus were constructed by using Doppler colour flow mapping with a previously validated time‐interpolation method. The pattern of flow convergence in the left ventricular outflow tract was quantified by measuring the colour flow areas on the anterior and posterior sides of the central axis of the aortic annulus, and calculating their difference. The dynamic changes of the velocity distribution, the pattern of flow convergence and the septal angle throughout systole were observed.

The velocity distribution in the aortic annulus changed according to the pattern of flow convergence in the left ventricular outflow tract. During early systole, the pattern of flow convergence was most asymmetrical. With the central longitudinal axis of the aortic annulus as a reference, the main part of the converging flow was along the anterior wall of the left ventricular outflow tract. Consequently, the velocity profile in the aortic annulus was most skewed during the early systole, with the highest velocity along the anterior wall. Towards late systole, the pattern of flow convergence became more and more symmetrical, and the velocity distribution in the aortic annulus gradually became flat. A significant correlation was found between the extent of asymmetry of the pattern of flow convergence in the left ventricular outflow tract and the extent of skewness of the velocity distribution in the aortic annulus (r=0.69, P<0.001). Throughout systole, septal angle increased very slightly (from 35 ±3 to 38 ±3 degrees, P<0.01).
Effects of exposure to morning bright light in the blind and sighted controls
Authors: Partonen T. , Vakkuri O. , Lamberg‐Allardt C.
Published: April 2008

Summary. Seven blind subjects and 11 sighted controls were exposed to 3300 lux of cool‐white fluorescent light for either 1 h or 15 min in the morning for 2 weeks during the winter. Serum 25‐hydroxyvitamin D3 concentration, melatonin concentration in saliva, body temperature from the armpit, subjective sleepiness, and depressive symptoms were measured before and after the 2‐week trial. The intervention resulted in a significant elevation in the concentration of melatonin at 21.00 hours in the healthy controls but at 23:00 hours in the blind subjects. The body temperatures measured were increased in the controls but decreased in the blind in the morning following the cessation of the intervention, and these opposite changes resulted in significant differences in the temperatures between the two groups. The decreases in the body temperature were associated with the increases in the levels of melatonin in the blind but not in the controls. Bright light administered in the morning decreased subjective sleepiness and improved mood in the healthy controls and in the blind subjects as well. The intervention had no effect on the levels of vitamin D in either of the two groups.
No differential effects of porcine and human insulin on muscle sympathetic nerve activity during euglycaemia or hypoglycaemia
Authors: Frandsen H. A. , Snitker S. , Christensen N. J. , Madsbad S.
Published: April 2008

Summary. On the basis of some clinical studies in diabetic patients, and experimental studies in normal humans, it has been suggested that hypoglycaemic autonomic responses are augmented with porcine (PI) compared to human insulin (HI). A difference in sensory processing has been reported following insulin‐induced hypoglycaemia with PI compared to HI, and has been interpreted as different insulin effects on the central nervous system. In a double blind crossover comparison of HI and PI in nine healthy subjects, microneurographic recordings of muscle sympathetic nerve activity (MSNA) were performed, as well as measurements of cardiovascular and hormonal responses during a low dose hyperinsulinaemic euglycaemic glucose clamp (plasma insulin 60.1 ±1.9 mU ml‐1 (mean ± SEM)), followed by a period of insulin‐induced hypoglycaemia. Plasma insulin and glucose were identical in the two sessions. Plasma glucose nadir during hypoglycaemia was 2.4 ± 0.2 mmol 1‐1 for HI and 2.5 ±0.1 mmol l‐1 for PI. During euglycaemia, MSNA increased from 24 ± 2 to 34 ± 3 and 23 ± 2 to 30 ± 2 burst/min (P:NS) for HI and PI, respectively, and during hypoglycaemia to 49 ± 4 and 45 ± 2 bursts min‐1 (P:NS), respectively. The maximal hypoglycaemic increments of MSNA were not different (HI 15 ± 4; PI 15 ± 2 bursts min‐1 (P: NS)) Responses of plasma noradrenaline and haemodynamic parameters did not differ either. This study does not indicate differing sympathetic responses to PI and HI in healthy humans. Evidence for a modulating effect of insulin on central sympathetic outflow was not found.
Influence of external pressure on transcutaneous oxygen tension and laser Doppler flowmetry on sacral skin
Authors: Colin D. , Saumet J. L.
Published: April 2008

Summary. The effects of external pressure upon transcutaneous oxygen tension (tcpO2) and skin blood flow (SKBF) over the sacral area were studied in 16 healthy volunteers. Pressure was applied on the sacral area using a special device which included tcpO2 and laser‐Doppler flowmetry probes. The mean values of tcpO2, SKBF and wave occurrence of the flow were analysed for 18 increasing pressure levels. A significant decrease of tcpO2 was observed from 40 mmHg (5.3 Kpa) of applied pressure, while we obtained a significant decrease of SKBF when the external pressure was at 20 mmHg (2.7 Kpa). Using a non‐linear regression model, we have found a fourth degree polynomial to describe the relationship between tcpO2 and SKBF according to increasing pressure. SKBF slow wave occurrence decreased when external pressure was at 10 mmHg (1.3 Kpa), while rapid wave occurrence significantly decreased only at 120 mmHg (16.1 kPa) pressure.
A simple, non‐invasive and inexpensive method for evaluating the displacement of local tissue surfaces: from vascular changes to muscle contraction
Authors: Roatta S. , Deriu F. , Artusio E. , Passatore M.
Published: April 2008

Summary. This paper describes a non‐invasive, very inexpensive method of estimating tissue displacements of various origin that is easy and fast to set up. This technique utilizes an inductive proximity sensor (IPS), which is a non‐contact length transducer measuring the distance between its probe and a metal target. Its working principle is based on the electromagnetic coupling originating between the sensor probe, a source of high‐frequency magnetic field, and the metal target where parasitic currents take place. The linear working range of the IPS model used here is 0.1 to 6 mm probe‐target distance, its resolution is about 2 μm. The IPS has been employed on rabbits and humans to measure the displacement of a target glued to the skin of various body areas with respect to the fixed probe of the sensor. Its high resolution, together with an extensive working range, allows the evaluation of numerous physiological events which produce displacements ranging from 2 μm‐to 9 mm, reflecting either tissue volume changes or movements. In particular, an interesting application is to monitor, through volume variations, the extent and the time course of local vascular modifications induced by manoeuvres which elicit changes in vasomotor tone; vascular filling, tissue swelling etc. Therefore, this measure may be considered a ‘surface plethysmography’ record. In addition, the contractions of skeletal muscles, under either isotonic or isometric conditions, can be estimated through this sensor. This system may therefore find applications for research purposes and practical demonstrations to students.
Improved gas exchange during exercise after weight loss in morbid obesity
Authors: Hakala K. , Mustajoki P. , Aittomäki J. , Sovijärvi A.
Published: April 2008

Summary. The aim of this study was to determine the effect of weight loss induced by 6 weeks very‐low‐calorie‐diet (VLCD) and behavioural intervention on pulmonary gas exchange during exercise in non‐smoking morbid obese (BMI>40 kg/m2) otherwise healthy patients. Seven obese patients underwent a maximal bicycle ergometer test with continuous analysis of expired air and arterial blood sampling before and after a mean weight loss of 18% (25.7 kg, range: 10.50 kg). Body mass index (BMI) decreased with weight loss from 46.6 (6.3) kg/m2 to 38.0 (4.7) kg/m2 (P < 0.01). Oxygen consumption (VO2) at low and submaximal exercise levels decreased after weight reduction, but the change was not statistically significant. The peak oxygen consumption related to body weight (VO2/kg) increased 22% from the initial 16.2 (3.6) ml/min/kg to 19.8 (3.1) ml/min/kg (P < 0.05). Decrease in VCO2 was significant at submaximal exercise level. Ventilatory equivalent for CO2 increased significantly after weight reduction (P < 0.05). Standing up and light exercise resulted in a significant increase in the mean arterial oxygen tension (PaCO2) (P < 0.05) and a significant decrease in the mean alveolar‐arterial difference P(A‐a)O2 (P < 0.05) when compared to supine values. The mean increase in PaO2 with weight loss was not significant. The peak P(A‐a)O2 decreased significantly after weight reduction.

In conclusion, weight reduction induced by VLCD and behavioural intervention without exercise therapy can improve gas exchange during exercise in morbid obesity. Increased wasted ventilation, and a tendency to alveolar hyperventilation, after weight loss may reflect a delay in the adaptation of regulation of breathing to rapid weight loss.