Search results for "Lactates"

Long survival time of an isolated perfused rat brain

1972

Fatigue in a simulated cross-country skiing sprint competition

2009

The aim of this study was to assess fatigue during a simulated cross-country skiing sprint competition based on skating technique. Sixteen male skiers performed a 30-m maximal skiing speed test and four 850-m heats with roller skies on a tartan track, separated by 20 min recovery between heats. Physiological variables (heart rate, blood lactate concentration, oxygen consumption), skiing velocity, and electromyography (EMG) were recorded at the beginning of the heats and at the end of each 200-m lap during the heats. Maximal skiing velocity and EMG were measured in the speed test before the simulation. No differences were observed in skiing velocity, EMG or metabolic variables between the he…

The psychophysiological influence of exertion and affect on sport-specific cognitive and physical performance

2022

Objectives: The purpose of the present study was to examine differences in cognitive and physical performance, affective states, perceived exertion, and physiological responses between trials with cognitive, physical, or combined cognitive and physical load. Design: Randomised cross-over trial. Methods: Highly trained competitive orienteers (n = 15 men; n = 10 women) completed three randomised trials comprised of: (1) sport-specific cognitive tests; (2) 35-minute cycling time trial; and (3) combined sport-specific cognitive tests and 35-minute cycling time trial. Measures taken during the trials recorded affective states, perceived exertion, heart rate, blood lactate, cycling watts, as well…

Acute in vivo administration of a fish oil-containing emulsion improves post-ischemic cardiac function in n-3-depleted rats

2006

International audience; A novel i.v. lipid preparation (MCT:FO) containing 80% medium chain-triacylglycerols and 20% fish oil was recently developed to rapidly replenish cell membrane phospholipids with omega 3 (n-3) polyunsaturated fatty acids (PUFA). In regard of this property, we investigated the effect of a single i.v. administration of MCT:FO on the recovery of cardiac function after ischemia in control and n-3-depleted rats. Results were compared with those obtained either with a control preparation, where FO was replaced by triolein (MCT:OO), or with saline. Saline (1 ml) or lipid preparation (also 1 ml) was injected as a bolus via the left saphenous vein. After 60 min the heart was …

Changes in microregional perfusion, oxygenation, ATP and lactate distribution in subcutaneous rat tumours upon water-filtered IR-A hyperthermia

1995

The effect of hyperthermia on microcirculatory and metabolic parameters in s.c. DS-sarcomas of different sizes on the hind foot dorsum of SD-rats was investigated. Hyperthermia was carried out using a novel water-filtered, infrared-A radiation technique. Heating was performed at a rate of 0.5 degrees C/min until 44 degrees C was achieved in the tumour centre, which was maintained for 60 min. Using a multichannel laser Doppler flowmeter, red blood cell flux could be assessed continuously and at several sites within the tumour tissue simultaneously. Substantial inter-site variations in laser Doppler flux (LDF) were observed during hyperthermia which were independent of tumour size, site of me…

Staphylococcal α-toxin provokes coronary vasoconstriction and loss in myocardial contractility in perfused rat hearts: Role of thromboxane generation

2000

Background —Cardiac performance is severely depressed in septic shock. Endotoxin has been implicated as the causative agent in Gram-negative sepsis, but similar abnormalities are encountered in Gram-positive sepsis. We investigated the influence of the major exotoxin of Staphylococcus aureus, staphylococcal α-toxin, in isolated perfused rat hearts. Methods and Results —α-Toxin 0.25 to 1 μg/mL caused a dose-dependent increase in coronary perfusion pressure that more than doubled. In parallel, we noted a decrease in left ventricular developed pressure and the maximum rate of left ventricular pressure rise (dP/dt max ), dropping to a minimum of <60% of control. These changes were accompani…

Exhaustive physical exercise causes oxidation of glutathione status in blood: Prevention by antioxidant administration

1992

We have studied the effect of exhaustive concentric physical exercise on glutathione redox status and the possible relationship between blood glutathione oxidation and blood lactate and pyruvate levels. Levels of oxidized glutathione (GSSG) in blood increase after exhaustive concentric physical exercise in trained humans. GSSG levels were 72% higher immediately after exercise than at rest. They returned to normal values 1 h after exercise. Blood reduced glutathione (GSH) levels did not change significantly after the exercise. We have found a linear relationship between GSSG-to-GSH and lactate-to-pyruvate ratios in human blood before, during, and after exhaustive exercise. In rats, physical…

Continuous monitoring of mixed venous oxygen saturation in infants after cardiac surgery

1989

Continuous mixed venous oxygen saturation (SvO2c) was measured in 16 infants immediately after cardiac surgery. A polyurethane 4F, dual channel catheter (Opticath, Modell U440, Oximetrix) with fiberoptic filaments was introduced into the pulmonary artery during cardiothoracic surgery. The catheters were left in place for an average of 67.5 h (range 27 h -125 h) and there were no catheter-related complications. Correlation between continuous in vivo SvO2 values and in vitro values was satisfactory (r = 0.85), whereas a correlation between SvO2c and arterial oxygen saturation (SaO2) was not found (r = 0.07). The sampled arterial lactate values were inversely correlated to the simultaneously m…

Thimerosal induces calcium mobilization, fructose 2,6-bisphosphate synthesis and cytoplasmic alkalinization in rat thymus lymphocytes

1991

The effect of thimerosal on intracellular calcium ([Ca2+]i), pH (pHi) and fructose 2,6-bisphosphate (Fru 2,6-P2) in thymus lymphocytes was investigated. The effect of thimerosal on cell growth was also examined. Thimerosal produced a dose-dependent increase in [Ca2+]i, pHi and in the level of fructose 2,6-bisphosphate. Thimerosal was, however, unable to produce cell proliferation and inhibited [3H]thymidine incorporation when cells were challenged with PHA and costimulator. In the absence of external calcium, thimerosal produced only a slight increase in [Ca2+]i. In Na(+)-containing buffer, thimerosal induced an initial acidification (0.05 +/- 0.01 pH units), followed by an alkalinization o…

Influence of therapeutic and toxic doses of neuroleptics and antidepressants on energy metabolism of the isolated perfused rat brain.

1973

The isolated perfused rat brain was used for a comparative study of the effects of promazine, imipramine, monodesmethyl promazine and desipramine on cerebral energy metabolism. After perfusion for 30 min or 1 h the brain levels of the following substrates and metabolites were estimated: P-creatine, creatine, ATP, ADP, AMP, glycogen, glucose, glucose-6-P, fructose diphosphate, dihydroxyacetone-P, pyruvate, lactate, α-ketoglutarate, and ammonia. Drug concentrations of 5·10−6 M and 10−5 M in the perfusion medium caused a significant decrease of glucose-6-P alone. When the drug concentration was raised to a toxic range (10−4 M), reflected in the EEG by the pattern of secondary discharges, an ac…