Exercise facilitates cerebral lactate uptake, likely by increasing arterial lactate concentration and hence the diffusion gradient across the blood-brain barrier. However, nonspecific β-adrenergic blockade by propranolol has previously reduced the arterio-jugular venous lactate difference (AV) during exercise, suggesting β-adrenergic control of cerebral lactate uptake. Alternatively, we hypothesized that propranolol reduces cerebral lactate uptake by decreasing arterial lactate concentration.
View Article and Find Full Text PDFObjectives: Optimized concurrent training regimes are warranted in physical training of military-, law enforcement- and rescue-personnel. This study investigated if four 15-min endurance training sessions weekly improve aerobic capacity and performance more than one 60-min endurance session weekly during the initial phase of a Basic Military Training program.
Design: A randomized training intervention study with functional and physiological tests before and after the intervention.
Objectives: Military-, rescue- and law-enforcement personnel require a high physical capacity including muscular strength. The present study hypothesized that 9 weeks of volume matched concurrent short frequent training sessions increases strength more efficiently than less frequent longer training sessions.
Design: A randomized training intervention study with functional and physiological tests before and after the intervention.
Studies of the resting brain measurements of cerebral blood flow (CBF) show large interindividual and regional variability, but the metabolic basis of this variability is not fully established. The aim of the present study was to reassess regional and interindividual relationships between cerebral perfusion and glucose metabolism in the resting brain. Regional quantitative measurements of CBF and cerebral metabolic rate of glucose (CMR) were obtained in 24 healthy young men using dynamic [O]HO and [F]fluorodeoxyglucose positron emission tomography (PET).
View Article and Find Full Text PDFThe effect of recombinant erythropoietin (rhEPO) on renal and systemic hemodynamics was evaluated in a randomized double-blinded, cross-over study. Sixteen healthy subjects were tested with placebo, or low-dose rhEPO for 2 weeks, or high-dose rhEPO for 3 days. Subjects refrained from excessive salt intake, according to instructions from a dietitian.
View Article and Find Full Text PDFErythropoietin (EPO) is expressed in human brain tissue, but its exact role is unknown. EPO may improve the efficiency of oxidative metabolism and has neuroprotective properties against hypoxic injuries in animal models. We aimed to investigate the effect of recombinant human EPO (rHuEPO) administration on healthy cerebral metabolism in humans during normoxia and during metabolic stress by inhalation of 10% O hypoxic air.
View Article and Find Full Text PDFIntroduction: Hypoxia is associated with increased capillary permeability. This study tested whether acute hypobaric hypoxia involves degradation of the endothelial glycocalyx.
Methods: We exposed 12 subjects to acute hypobaric hypoxia (equivalent to 4500 m for 2-4 h) and measured venous blood concentrations of biomarkers reflecting endothelial and glycocalyx degradation (catecholamines, syndecan-1, soluble CD40 ligand, protein C, soluble thrombomodulin, tissue-type plasminogen activators, histone-complexed DNA fragments, and nitrite/nitrate).
The membrane-assisted isoform immunoassay (MAIIA) quantitates erythropoietin (EPO) isoforms as percentages of migrated isoforms (PMI). We evaluated the effect of recombinant human EPO (rhEPO) on the distribution of EPO isoforms in plasma in a randomized, placebo-controlled, double-blinded, cross-over study. 16 healthy subjects received either low-dose Epoetin beta (5000 IU on days 1, 3, 5, 7, 9, 11 and 13); high-dose Epoetin beta (30.
View Article and Find Full Text PDFThe local anaesthetic lidocaine is known to block voltage-gated Na(+) channels (VGSCs), although at high concentration it was also reported to block other ion channel currents as well as to alter lipid membranes. The aim of this study was to investigate whether the clinical regional anaesthetic action of lidocaine could be accounted for solely by the block of VGSCs or whether other mechanisms are also relevant. We tested the recovery of motor axon conduction and multiple measures of excitability by 'threshold-tracking' after ultrasound-guided distal median nerve regional anaesthesia in 13 healthy volunteers.
View Article and Find Full Text PDFTo determine patient priority and degree of urgency with an objective high-quality evaluation, general Point of Care testing (POCT) was established as a novel facility in the emergency department at Holbæk Hospital, a laboratory that provides faster results for common lab tests. When evaluating response time from arrival of the patient to the time at which the test results are available, POCT is not a significantly better test method than ordinary test methods. This indicates that in order to benefit from POCT the time before taking blood samples should be reduced to a minimum.
View Article and Find Full Text PDFThe aim was to test the hypothesis that 7 days of bed rest reduces mitochondrial number and expression and activity of oxidative proteins in human skeletal muscle but that exercise-induced intracellular signaling as well as mRNA and microRNA (miR) responses are maintained after bed rest. Twelve young, healthy male subjects completed 7 days of bed rest with vastus lateralis muscle biopsies taken before and after bed rest. In addition, muscle biopsies were obtained from six of the subjects prior to, immediately after, and 3 h after 45 min of one-legged knee extensor exercise performed before and after bed rest.
View Article and Find Full Text PDFHaemoglobin concentration ([Hb]), reticulocyte percentage (retic%) and OFF(hr score) are well-implemented screening tools to determine potential recombinant human erythropoietin (rHuEpo) abuse in athletes. Recently, the International Cycling Union implemented the OFF(z score) and the Hb(z score) in their anti-doping testing programme. The aim of this study is to evaluate the sensitivity of these indirect screening methods.
View Article and Find Full Text PDFContext: The GH/IGF-I axis has major impact on insulin sensitivity and insulin secretion. Recently a polymorphism in the GH receptor gene (GHR), a genomic deletion of exon 3 (GHRd3), has been linked to increased responsiveness to GH.
Objective: The objective of the present study was to evaluate the impact of the GHRd3 gene polymorphism on insulin sensitivity, insulin secretion, lipids, and IGF-I levels in healthy children and adolescents.
The high iron demand associated with enhanced erythropoiesis during high-altitude hypoxia leads to skeletal muscle iron mobilization and decrease in myoglobin protein levels. To investigate the effect of enhanced erythropoiesis on systemic and muscle iron metabolism under nonhypoxic conditions, 8 healthy volunteers were treated with recombinant erythropoietin (rhEpo) for 1 month. As expected, the treatment efficiently increased erythropoiesis and stimulated bone marrow iron use.
View Article and Find Full Text PDFObjective: Early puberty is associated with increased risk of subsequent cardiovascular disease. Low sex hormone-binding globulin (SHBG) levels are a feature of early puberty and of conditions associated with increased cardiovascular risk. The aim of the present study was to evaluate SHBG as a predictor of glucose metabolism and metabolic risk during puberty.
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