Jorma Hirvonen

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Fatigue during the 400-m sprint was studied by measuring muscle ATP, creatine phosphate (CP), lactate (M-La), and blood lactate (B-La) in six male runners before and after four experimental sprints (100, 200, 300, and 400 m). During the first 100 m, muscle CP decreased from 15.8 +/- 1.7 to 8.3 +/- 0.3 mmol/kg while M-La increased to 3.6 +/- 0.4 mmol/kg.(More)
Muscle ATP, creatine phosphate and lactate, and blood pH and lactate were measured in 7 male sprinters before and after running 40, 60, 80 and 100 m at maximal speed. The sprinters were divided into two groups, group 1 being sprinters who achieved a higher maximal speed (10.07±0.13 m ·s−1) than group 2 (9.75±0.10 m ·s−1), and who also maintained the speed(More)
Fourteen sprinters were assigned to an experimental group (N = 7) and a control group (N = 7) in order to study the effects of 3 wk of extra-load conditioning. The extra-load conditioning was achieved by the athletes wearing special vests containing weights (7-8% body mass). The vests were used from morning to evening and during 3-5 training sessions/wk for(More)
OBJECTIVE Fructose-1,6-bisphosphate is a high-energy intermediate in the anaerobic metabolism. It enhances glycolysis, preserves cellular adenosine triphosphate, and prevents the increase of intracellular calcium during ischemia. The potential neuroprotective effect of fructose-1,6-bisphosphate during hypothermic circulatory arrest was evaluated in a(More)
OBJECTIVE To evaluate whether electroencephalography (EEG) recovery could be considered a reliable marker of brain injury after experimental hypothermic circulatory arrest (HCA). DESIGN Cortical electrical activity was registered before and after a 75-min period of HCA in 27 pigs that survived 7 days after the experiment. The sum of EEG bursts was counted(More)
Neuromuscular and anaerobic performance was investigated in nine male sprinters who were running at maximal and supramaximal speeds. Supramaximal running was performed by a towing system. A rubber rope pulled by an electronic motor towed the runner, and the angle of draught ranged from 10 degrees to 17 degrees upward from the horizontal. All runs were(More)
BACKGROUND The superiority of the pH-stat to the alpha-stat acid-base strategy during cardiopulmonary bypass as a neuroprotective method during hypothermic circulatory arrest is still controversial. In the present study, brain metabolism and outcome have been evaluated in a surviving model of experimental hypothermic circulatory arrest. METHODS Twenty(More)
OBJECTIVES We sought to evaluate the potential efficacy of prolonged mild hypothermia after hypothermic circulatory arrest. METHODS Twenty pigs, after a 75-minute period of hypothermic circulatory arrest, were randomly assigned to be rewarmed to 37 degrees C (normothermia group) or to 32 degrees C and kept at that temperature for 14 hours from the start(More)
Rats were kept at −20°C until they died. Stomach erosions were found in every rat exposed to cold. Histamine and serotonin were visualized by fluorescence microscopy and their quantities were measured fluorometrically. Histamine fluorescence had disappeared in the erosion region from mucosal mast cells and enterochromaffin-like cells. Submucosal mast cells(More)
OBJECTIVE An increase in intracranial pressure has been shown to threaten the outcome of patients with ischemic or traumatic brain injury. Its impact on the outcome of pigs undergoing hypothermic circulatory arrest has been evaluated in this study. DESIGN Fifty-six pigs underwent a 75-min period of hypothermic circulatory arrest at 20 degrees C.(More)