Search results for "Trace"
showing 10 items of 3218 documents
Intracellular acidosis in murine fibrosarcomas coincides with ATP depletion, hypoxia, and high levels of lactate and total Pi
1994
Bioenergetic and metabolic status of murine FSaII tumours were evaluated using 31P MRS, acid extracts ('global' techniques) and quantitative bioluminescence ('microregional' assay). Data obtained from s.c. tumours of varying sizes (44-600 mm3) have been correlated with the oxygenation status evaluated using O2-sensitive needle electrodes. beta-NTP/Pi and phosphocreatine (PCr)/Pi ratios derived from 31P MRS were positively correlated to the median tissue pO2 values. pH declined during growth with intracellular acidosis being evident in tumours > 350 mm3. Whereas lactic acid formation greatly contributed to this decline in small- and medium-sized tumours, ATP hydrolysis and slowing down of th…
MUSCLE BIOENERGETICS IN OBESE ZUCKER RATS
1994
International audience; Abstract: The purpose of this study was to investigate the energetic metabolism in obese Zucker rats, using phosphorus nuclear magnetic resonance spectroscopy at rest and during a 2-Hz muscle stimulation and subsequent recovery. Animals were anesthetized with ketamine (150 mg/kg ip). Fed obese rats and 2-day-fasted obese rats were compared with their normally fed and 2-day-fasted lean litter mates. No differences were found between the two groups for ATP, total creatine, phosphocreatine (PCr), and intracellular pH. Starvation in lean rats resulted in a significant fall in inorganic phosphate (Pi), increased resting ADP level, and decreased PCr and ADP recovery after …
Intestinal ischaemia during cardiac arrest and resuscitation: comparative analysis of extracellular metabolites by microdialysis.
2003
Intestinal ischaemia is a major complication of shock syndromes causing translocation of bacteria and endotoxins and multiple organ failure in intensive care patients. The present study was designed to use microdialysis as a tool to monitor intestinal ischaemia after cardiac arrest and resuscitation in pigs. For this purpose, microdialysis probes were implanted in pig jejunal wall, peritoneum, skeletal muscle and brain, and interstitial fluid was obtained during circulatory arrest (induced by ventricular fibrillation) and after return of spontaneous circulation (ROSC). Cardiac arrest for 4 min caused a prolonged (60 min) reduction of blood flow in jejunal wall, muscle and brain as determine…
Serotonergic modulation of hippocampal acetylcholine release after long-term neuronal grafting
2000
Adult female rats sustained aspirative fimbria-fornix lesions and, 2 weeks later, received intrahippocampal grafts of fetal septal or mixed septal-raphe cell suspensions. Twenty-four months later, the extracellular concentration of hippocampal acetylcholine (ACh) was determined by microdialysis. Basal ACh levels (5-65 fmol/5 microl sham-operated rats) were strongly reduced after lesioning (3-7 fmol/5 microl). In septally transplanted and septal-raphe co-transplanted rats, hippocampal ACh concentrations were restored to near-normal levels (15-25 fmol/5 microl), indicating long-term functional survival of hippocampal transplants. After administration of citalopram (100 microM by infusion) and…
The neuronal efflux of noradrenaline: Dependency on sodium and facilitation by ouabain
1974
Rabbit hearts were isolated after pretreatment with the MAO inhibitor pargyline and with reserpine and were perfused with 200 ng/ml noradrenaline for 1 h. During the subsequent wash-out with an amine-free solution for 2 h, the neuronal efflux of noradrenaline declined mono-exponentially with a mean halftime of 42 min. Both Na+-free solution and ouabain caused facilitation of the efflux which thereafter declined in a multi-exponential fashion. The maximum facilitation was reached after 3 min of Na+-free perfusion and 25 min after introduction of ouabain. The amount of exogenous noradrenaline accumulated in the heart was only partially released when the extracellular Na+-concentration was nor…
The pathological hallmarks of Alzheimer’s disease derive from compensatory responses to NMDA receptor insufficiency
2018
AbstractAlzheimer’s disease is characterized by intracellular aggregates of hyperphosphorylated tau protein and extracellular plaques of amyloid β peptide, a product of APP processing. The origin of these pathological hallmarks has remained elusive. Here, we have tested the idea that both alterations, at the onset of the disease, may constitute compensatory responses to the same causative and initial trigger, namely NMDA receptor insufficiency. Treatment of rat cortical neurons with the specific NMDA receptor antagonist AP5 within 4 h caused a significant increase in tau phosphorylation at the AT8 and S404 epitopes as well as an increase in APP expression and Aβ 40 secretion. Single intrape…
Inhibitory effects of okadaic acid on rat uterine contractile responses to different spasmogens
1997
In the present study, we examined the effects of okadaic acid, a selective inhibitor of type I and 2A protein phosphatases, on the mechanical responses evoked by oxytocin, K + - and Na + -modified solutions and ouabain in estrogen-primed rat myometrium. Oxytocin elicited a rapid, phasic contraction followed by rhythmic oscillations. The phasic response was partially resistant to the absence of external Ca 2+ . Okadaic acid (1 μM) and the L-type calcium channel blocker nifedipine (1 μM) abolished the oscillatory component and reduced the initial, phasic response to about 80% of the control response. High K + (60 mM) solution, ouabain (1 mM), K + -free medium and low Na + (25 mM) solution ind…
Oxygen and glucose deprivation induces major dysfunction in the somatosensory cortex of the newborn rat
2005
The mechanisms and functional consequences of ischemia-induced injury during perinatal development are poorly understood. Subplate neurons (SPn) play a central role in early cortical development and a pathophysiological impairment of these neurons may have long-term detrimental effects on cortical function. The acute and long-term consequences of combined oxygen and glucose deprivation (OGD) were investigated in SPn and compared with OGD-induced dysfunction of immature layer V pyramidal cortical neurons (PCn) in somatosensory cortical slices from postnatal day (P)0-4 rats. OGD for 50 min followed by a 10-24-h period of normal oxygenation and glucose supply in vitro or in culture led to pron…
Thrombin generation in cardiovascular disease and mortality – results from the Gutenberg Health Study
2020
Thrombin generation may be a potential tool to improve risk stratification for cardiovascular diseases. The aim of this study was to explore the relation between thrombin generation and cardiovascular risk factors, cardiovascular diseases, and total mortality. For this study, 5,000 subjects from the population-based Gutenberg Health Study were analyzed in a highly standardized setting. Thrombin generation was assessed by the Calibrated Automated Thrombogram method at 1 and 5 pM tissue factor triggers in platelet-poor plasma. Lag time, endogenous thrombin potential, and peak height were derived from the thrombin generation curve. Sex-specific multivariable linear regression analysis adjusted…
SUBFRACTIONS AND SUBPOPULATIONS OF HDL: AN UPDATE
2014
High-density lipoproteins (HDL) are classified as atheroprotective because they are involved in transport of cholesterol to the liver, known as "reverse cholesterol transport (RCT)" exerting antioxidant and anti-inflammatory activities. There is also evidence for cytoprotective, vasodilatory, antithrombotic, and anti-infectious activities for these lipoproteins. HDLs are known by structural, metabolic and biologic heterogeneity. Thus, different methods are able to distinguish several subclasses of HDL. Different separation techniques appear to support different HDL fractions as being atheroprotective or related with lower cardiovascular (CV) risk. However, HDL particles are not always prote…