bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes in coronary haemodynamics and myocardial metabolism at rest and during exercise after a cardiotonic drug (prenalterol) in patients with coronary artery disease
Authors: Westheim A. , Bae E. , Christensen C. C. , Fønstelien E. , Grendahl H. , Muller O. 
Published: April 2008

Summary. To elucidiate the myocardial metabolic and haemodynamic effects of an inotropic drug in patients with coronary artery disease (CAD) without evident congestive heart failure (CHF), the acute effects of prenalterol were studied in nine patients. Patients with documented CAD by leftsided cardioangiography and end‐diastolic pressure >15 mm Hg were included in the study. They were examined at rest and during supine exercise at a level just below their anginal threshold before and after prenalterol.At rest, rate pressure product (RPP) increased by 40% (P<0·01), cardiac index rose 20% (P<0·01), cardiac venous flow (CVF) increased by 18% (P<0·05), and myocardial oxygen consumption (MVO2) increased by 20% (P<0·05) after prenalterol administration. Despite a decrease in mean pulmonary capillary venous pressure (PCV) of 40% (P<0·01), myocardial lactate extraction fell significantly (P<0·01) and lactate production was observed in three of nine patients compared to before prenalterol administration. During exercise, RPP increased by 20% (P<0·01), cardiac index remained unchanged, CVF increased by 25% (NS) and MV02 showed a tendency to an increase (NS) after prenalterol administration. Mean PCV pressure decreased by 30% (P<0·01). Myocardial lactate extraction was markedly reduced during exercise (P<0·01) and five of nine patients showed lactate production compared to that before prenalterol administration. Thus, despite a decrease in left ventricular filling pressure, increased myocardial oxygen demand occurred after acute administration of prenalterol. Prenalterol and probably similar inotropic drugs should be used cautiously in patients with CAD without clinical evidence of congestive heart failure.
Effects of propranolol and verapamil on plasma ionized calcium and parathyroid hormone in short‐term intense isokinetic leg exercise
Authors: Joborn H. , Bergström R. , Rastad J. , Wide L. , Åkerström G. , Ljunghall S. 
Published: April 2008

Summary. Physical exercise, beta‐adrenergic stimulation and calcium channel blockade can affect calcium homeostasis. The present study investigated, in eight healthy males, the effects of orally administered propranolol or verapamil during a 2‐min maximal, isokinetiC., leg exercise.Immediately after exercise the plasma ionized calcium concentrations were increased, in control and drug tests, by 5–6%, and within 5 min of recovery they were almost returned to baseline. Serum parathyroid hormone (PTH) concentrations were unchanged at termination of exercise, but they increased during the first 5 min of recovery, coincident with the decline in calcium concentrations, which, however, were still elevated. Neither verapamil nor propranolol selectively changed basal or exercise plasma ionized calcium or serum PTH concentrations. Muscle strength, blood pH, lactate concentrations and plasma volume changes were not affected by any drug. Verapamil did not have any specific effect on the concentrations of plasma magnesium, phosphate, potassium or sodium while propranolol increased the concentrations of plasma potassium and decreased those of phosphate during exercise as well as recovery.
The low physical working capacity of thyrotoxic patients is not normalized by oral antithyroid treatment
Authors: Sestoft L. , Saltin B. 
Published: April 2008

Summary.The low working capacity in thyrotoxic patients has not been quantified and its causes have not been clarified. We studied the working capacity in nine thyrotoxic patients at diagnosis (test 1), after 3 months of oral antithyroid medication (test 2), and in four of them again after 1 year (test 3). The maximum power output was low in thyrotoxic patients (1·65 ±0·15 W/kg‐1) and was not significantly higher after 3 months of treatment (1·84 ±0·15), although plasma thyroid hormone concentrations had been normalized for approximately 3 months. After 1 year's treatment the maximum power output was still somewhat low in the four tested patients (2·75 ±0·34). The rate of oxygen uptake under maximum exercise was low (26 ml/ min‐1/kg‐1) and was not significantly increased at test 2 and 3. The net mechanical efficiency was low at test 1 and 2 (18·9 ±2·1% and 20·1 ± 1·8%, respectively), but was normal at test 3 (25·2%). At all three tests the blood lactate response upon maximum exercise attained only about 50% of normal concentration.Thus, low work capacity in thyrotoxic patients remained for a long period of time after euthyroid conditions had been attained. The low capacity was due to low aerobic and anaerobic capacities and initially also to a low mechanical efficiency.
Prostacyclin and regional coronary blood flow in experimental myocardial infarction
Authors: Herbaczynska‐Cedro K. , Karwatowska‐Prokopczuk E. , Michalowski J. , Wennmalm Å. 
Published: April 2008

SummaryInfusion of prostacyclin (PGI2) has been reported to affect infarct size and myocardial blood flow favourably in various animal models of myocardial ischaemia. Recent data suggest that a similar effect of PGI2 may occur also in humans with acute myocardial infarction. We addressed the hypothesis that PGI2 redistributes myocardial blood flow following coronary ligation, and that this effect favours perfusion of myocardium at risk and thereby limits infarct size. Following ligation of a distal branch of the left coronary artery in anaesthetized dogs, PGI2 (2–4 ng/kg/min) was infused for 72 h. Regional myocardial blood flow was assessed immediately after the coronary ligation and at the end of the drug infusion, by injection of 57Co‐ and 113Sn‐labelled microspheres, respectively. Coronary ligation reduced regional coronary blood flow by 40–70%. During the subsequent 72 h the blood flow increased, being at the end of the period 50–70% of the flow in the non‐ischaemic myocardium. PGI2 did not affect the spontaneous improvement of regional myocardial blood flow, as assessed at the end of the infusion. PGI2 also failed to affect infarct size, either when expressed in relation to total left ventricular mass, or in relation to area at risk. We conclude that PGI2, when infused immediately after coronary ligation in dogs in a clinically relevant dose, neither affects regional myocardial blood flow in the ischaemic regions, nor the size of the myocardial infarction.
Regional blood volume in man determined by radiolabeled erythrocytes
Authors: Vissing S. Fløistrup , Nielsen S. Levin 
Published: April 2008

SummaryThe purpose of the present study was to develop a non‐invasive method capable of measuring the regional blood volume in the peripheral circulation. External counting of autologous radiolabeled erythrocytes was performed by dynamic scintigraphy of the calf. During short venous stasis synchronous changes in segmental blood volumes were recorded by plethysmography, thereby obtaining a calibration factor. The recordings were performed with the position of the calf varying between elevated, horizontal and lowered before and after 4·5 min venous stasis with a tourniquet pressure on 57 mmHg applied above the knee. The mean blood volume comprised 3·2 (1·2 ml per 100 ml tissue in the elevated position, 6·0 (1·6) in the horizontal position and 9·8 (2·6) in the lowered position. Correspondingly, the blood volume increase during venous stasis was 120%, 60% and 20% in the three positions. Studies of the reproducibility showed a coefficient of variation of 13.5%. The present study suggests that the method of blood volume measuring should be further evaluated to study the function of capacitance vessels.
Single and multiple breath nitrogen wash‐out—closing volume and volume of trapped gas for detection of early airway obstruction
Authors: Dahlqvist M. , Alexandersson R. , Nielsen J. , Hedenstierna G. 
Published: April 2008

Summary. Thirty‐eight patients with varying degrees of peripheral airway involvement were studied by flow–volume curves and two nitrogen wash‐out techniques in an on‐site study. Closing capacity (CC), closing volume in percentage of vital capacity (CV%), slope of the alveolar plateau (phase III), volume of trapped gas (VTG), and maximum expiratory flow at 50 and 75% of vital capacity (MEF50, MEF25) were determined and correlation analyses were performed.A biphasic or exponential correlation was noted between the degree of airway closure and VTG with rapidly increasing VTG at high CC. Although there were correlations between spirometry and the two nitrogen wash‐out techniques, a large scatter precluded the use of the flow–volume variables to predict CC, CV% and VTG.The coefficient of variation was lower for the measurements of CV% than for the recording of VTG. Since the single breath nitrogen wash‐out technique is also technically simpler it is recommended prior to the multiple breath technique.
Blood volume after coronary artery bypass grafting
Authors: Ivert T. , Pehrsson S. K. , Landou C. , Magder S. , Holmgren A. 
Published: April 2008

Summary. Patients with stable angina pectoris are reported to have a markedly reduced blood volume (BV). In the present study, average BV was still 19% less than that predicted in 77 men examined 5 years after coronary artery bypass grafting. Beneficial effects of the operation such as relieved angina, absence of medication, complete revascularization status at repeat angiography, and restored physical fitness were not found to be associated with a normalization of the BV. No significant correlation was found between BV and body weight, heart volume, exercise capacity, ejection fraction or left ventricular end‐diastolic pressure.The reduced BV in patients with angina pectoris after successful revascularization and the absence of correlation with physiological variables indicate a persisting disturbed regulation mechanism.
Diminished meal‐induced thermogenesis in elderly man
Authors: Thörne A. , Wahren J. 
Published: April 2008

Summary. The purpose of this study was to examine the possible influence of age on the thermogenic response to a mixed meal in healthy subjects. Twenty‐five healthy male subjects participated in the study and they were divided into three groups, comprising 10 young subjects with an average age of 27 years (22–35 years), seven middle‐aged individuals (51 years, 42–60 years) and eight elderly men (70 years, 67–74 years). They were all studied with continuous indirect calorimetry in the basal state and for 3 h after the ingestion of a mixed meal in liquid form. The size of the meal corresponded to 60% of the individually computed 24‐h basal energy expenditure.Resting energy expenditure was lower in the elderly men than in the young ones when expressed in absolute values (P<0.001) as well as in relation to body weight (P<0.01) and body surface area (P<0.01). After the meal energy expenditure increased rapidly and reached a relatively constant level after 60 min in all groups; the average increase above the basal level during the whole postprandial period was less in the elderly (21.1±2.5%, P<0.01) and the middle‐aged (24.2±1.7%, P<0.05) than in the young (28.6±1.6%) men.It is concluded that the thermogenic response during the first 3 h following a mixed meal decreases with age and that this diminished meal‐induced thermogenesis may contribute to lower nutrient requirements in old age.
Oesophageal transit in patients with autonomic dysfunction. The effect of treatment with fludrocortisone
Authors: Jørgensen F. , Boesen F. , Andersen E. B. , Hesse B. 
Published: April 2008

Summary. Oesophageal function was examined by radionuclide transit measurements in 15 patients with severe autonomic deficiency and orthostatic hypothension and 23 healthy volunteers. Seven of the patients were re‐examined after treatment for 3 weeks with fludrocortisone acetate (Florinef®). Six patients and five control subjects were evaluated before and after i. v. administration of atropine.The mean transit time (MTT) was prolonged (P<0.007) and the residual activity increased (P= 0.038) in the patients compared with the control group. Prolonged MTT was associated with oesophageal symptoms.Treatment of orthostatic hypotension with fludrocortisone acetate significantly reduced MTT. Atropine increased MTT and residual activity. The increase in heart rate after atropine was correlated in the patients with MTT before treatment.The results demonstrate the frequent presence of impaired oesophageal function in patients with severe autonomic dysfunctiion, irrespective of aetiology. The impairment seems to be closely relatded to parasympathetic insufficiency. The improvement after fludrocortisone may suggest an influence of ion balance on oesophageal function in these patients.
Preserved CO2 response in cerebral and muscular blood vessels during cimetidine treatment
Authors: Saunier C. , Audibert G. , Hartemann D. , Sautegeau A. , Amend P. , Bigard O. , Alvernhe C. 
Published: April 2008

Summary. It is known that cimetidine inhibits the hypoxia‐induced increase in cerebral blood flow (CFB) in dogs, but the mechanism of this inhibition is not fully understood.Since the accepted mechanisms explaining the increase in CBF during hypercapnia are very different from those active during hypoxia, acute hypercapnia was induced in 12 conscious dogs in order to study the cimetidine effect in this condition. Six dogs were given i.v. saline (control group) and the other six, i.v. cimetidine (4 mg kg1). After 15 min, CBF and various muscular blood flow measurements were performed, using the microspheres technique under two conditions: (1) breathing air and (2) after 2 h inhalation of a gas mixture with Fico2 0·10, Fio2 0·21 in nitrogen. The CBF increase was similar in both series with or without cimetidine. The changes in muscular blood flow were unaffected by the H2blocker. We conclude that cimetidine has no effect on the CBF and on muscular blood flow during acute hypercapnia.
Effect of coronary bypass surgery on anaerobic myocardial lactate metabolism during pacing‐induced angina pectoris
Authors: Kaijser L. , Gunnes S. , Berglund B. 
Published: April 2008

SUMMARYMyocardial lactate metabolism was studied by coronary sinus catheterization in nine patients before and 8–12 months after coronary bypasss surgery. Measurements were performed at rest and during atrial pacing increased to a heart rate which produced strong chest pain. The estimation of myocardial lactate extraction and release was facilitated by a constant rate infusion of 14C lactate and coronary sinus blood flow (CSBF) was measured by thermodilution. Pre‐operatively strong chest pain could be elicited in all patients and isotope data indicated a significant myocardial lactate release in all of them, although the net a‐cs difference was negative in only half of them. After bypass surgery the maximum tolerable heart rate was increased by 23 beats min1 and chest pain both at heart rate 110 beats min1 and at the highest heart rate achieved was reduced or absent in eight of the nine patients. The increase in chest pain during pacing was quantitatively related to the increase in myocardial lactate release, and the correlation between these two variables followed the same course after the operation as it did before. It is concluded that the improvement in chest pain limited cardiac performance after bypass surgery is well correlated with the improvement in myocardial aerboic metabolism.
Ischaemic heart disease and the changes in the QRS and ST segments during exercise: a pilot study with a novel vectorcardiographic system
Authors: Pilhall M. , Riha M. , Jem S. 
Published: April 2008

Summary. In order to find new ischaemic parameters, the spatial changes of the Frank vectorcardiogram were continuously analysed with a new, highly precise vectorcardiographic method during, and immediately after a maximal exercise test. This was done in 18 young healthy males, and 18 patients with scintigraphic reversible ischaemia.During exercise, different patterns between the groups were noted for the changes in the mean QRS magnitude in the Y‐lead (P< 0.005), the QRS‐integral (P<0.05), and the QRS‐duration (P<0.05). Immediately after exercise, several QRS parameters in the normal group continued to change according to the same pattern as during exercise (P<0.05), which was in contrast with the patterns of the ischaemic group (P<0.01). The spatial ST difference at J+20 ms discriminated well between the groups, especially when corrected for QRS‐magnitudes at rest and heart rate (P< 0.0005).In short, this pilot study supports previous findings in that changes in amplitude and duration of the QRS complex during exercise discriminated between healthy young males and patients with ischaemic heart disease. Moreover, rapid discriminating changes were seen in the QRS segment during cessation of exercise. These changes deserve attention since they may be of importance for the conflicting results on the diagnostic value of QRS changes during exercise.
Non‐invasive assessment of vessel‐wall changes in hypertensives and normotensive controls
Authors: Lemne C. , Jogestrand T. , de Faire U. 
Published: April 2008

Summary The aim of this study was to evaluate the feasibility of non‐invasive assessment of vessel wall changes in early, untreated hypertension. Measurement of intimal+medial (I‐M) thickness in the common carotid artery (CCA) using B‐mode ultrasound imaging showed no differences between 12 patients with untreated, newly diagnosed hypertension and 9 age‐matched controls (0.63 mm vs 0.63 mm just proximal to the carotid bulb).Echocardiography showed that the hypertensive group had thicker left ventricular walls (LVW) than the normotensive group. Correlation analyses disclosed that I‐M thickness was significantly associated with age (r= 0.63; P<0.05) for the whole material but not with blood pressure levels, serum lipids, or LVW thickness. These results imply that the arterial I‐M layers of the CCA are less responsive to pressure overload than the left ventricle.The feasibility of using I‐M thickness as an early marker of structural vessel wall changes in hypertensive patients must await results from large scale prospective studies. In view of the present results, age homogenous materials should be selected for such studies.
Pulmonary arterial wedge pressure measurement can modify pulmonary hae mo dynamics in patients with chronic lung disease
Authors: Schrijen F. V. , Serri A. , Chabo F. 
Published: April 2008

Summary. In 20 patients with chronic lung disease in stable condition, haemodynamic values were compared during wedging of a Swan‐Ganz catheter, either in a distal branch of the pulmonary artery, or by balloon inflation (with 1 ml) in a proximal branch, mostly excluding right lower lobe perfusion.Average pulmonary arterial wedge pressure, systemic arterial pressure, transcutaneous and mixed venous oxygen saturation, cardiac output and pulmonary blood volume (PBV) were not statistically different during distal and proximal wedging, but systolic pulmonary arterial pressure and pulmonary vascular resistance were slightly higher during balloon inflation (P < 0.05). In four patients, PBV decreased by 20% or more; cardiac output was reduced and mean systemic arterial pressure diminished by 10 mmHg or more in three patients. Of the two patients with the lowest PBV, one did not tolerate the balloon inflation because of dyspnoea, and the other showed dramatically haemodynamic changes. These were more likely to occur when the occlusion lead to the exclusion of a still well perfused area.Our results support optimal matching between ventilation and perfusion in patients with chronic lung disease, although both are inhomogeneous. When pulmonary vascular restriction can be suspected, pressure obtained during catheter wedging by balloon inflation should be interpreted with caution. Monitoring arterial oxygen saturation and systemic arterial pressure before and during the manoeuver could help to diagnose haemodynamic effects of the balloon inflation in a proximal pulmonary artery.
Postural effects on diastolic blood pressure are differently recorded by a non‐invasive ambulatory blood pressure monitor and a standard auscultatory device,
Authors: Schwan Å. 
Published: April 2008

Summary. The aim of this study was to determine the influence of change of posture on blood pressure as recorded with an automatic ambulatory blood pressure monitor and a standard auscultatory device.The blood pressure difference between sitting and supine and between standing and supine posture was 1.1/3.9 and 6.5/6.3 mmHg, respectively, for the monitor recordings, and 0.7/6.7 and 7.9/14.8 mmHg, respectively, for the standard recordings. All differences were significant, except the systolic blood pressure difference between sitting and supine posture. There were no significant differences in systolic blood pressure between monitor and standard recordings in any posture. The corresponding differences in diastolic blood pressure were significant in sitting (‐4.6 mmHg) and standing postures (‐10.3 mmHg), but not in supine posture (‐1.8 mmHg).It is concluded that a change of posture contributes to blood pressure variability, and agreement between diastolic blood pressure in supine subjects, as recorded by an ambulatory monitor and a standard device, does not necessarily mean agreement in standing (or sitting) subjects.
The separate and combined effect of leucine and insulin on muscle free amino acids
Authors: Essén P. , Heys S. D. , Garlicky P. , Wernerman J. 
Published: April 2008

Summary. The effect of insulin and leucine on amino acid and protein metabolism in muscle is not fully understood. To characterize their separate and combined effects on free amino acids in muscle and plasma, 11 volunteers received an infusion of either leucine (1 g h‐1, Group 1) or glucose (20 g h‐1, Group 2) for 2 h followed by a combination of the two infusions for an additional 2‐h period.In muscle both the leucine infusion and the leucine plus glucose infusion increased the concentration of free leucine significantly, while the sum of the other branched chain amino acids (BCAA), of the aromatic amino acids and of the basic amino acids decreased. Glucose infusion alone decreased the sum of the essential amino acids, the BCAA and the aromatic amino acids. The combination of leucine and glucose augmented the decreases, while the concentrations of glutamate, glutamine and alanine were unaffected.In plasma the leucine infusion doubled the leucine concentration and decreased alanine, valine, methionine, tyrosine, phenylalanine and the sum of the aromatic amino acids. Glucose infusion decreased methionine, serine, isoleucine and the sum of the essential amino acids and of the BCAA. The combination of leucine infusion and hyperinsulinaemia augmented the decreases. The plasma concentrations of the keto acids of valine and isoleucine decreased by the leucine infusion while the concentrations of the keto acid of leucine and isoleucine decreased by glucose infusion. The combination of leucine and glucose had an additive effect.These effects are attributed to a specific effect of leucine on the other two BCAA and a depression of muscle proteolysis by both leucine and insulin, resulting from glucose infusion.