Search results for "Energy charge"
showing 8 items of 8 documents
Most of the field/inductive substituent effect works through the bonds
2019
AbstractAn application of the quantum chemical modeling allowed to investigate the nature of the field/inductive substituent effect (SE). For this purpose, series of X-tert-butyl···tert-butane (TTX) complexes (where X = NMe2, NH2, OH, OMe, Me, H, F, Cl, CF3, CN, CHO, COMe, CONH2, COOH, NO2, NO) were studied. A starting distance between central carbon atoms in substituted and unsubstituted fragments of TTX, dC1–C4, was the same as the distance C1–C4 in X-substituted bicyclo[2.2.2]octane (BCO), where the SE acts both via bonds and via space. A strength of interaction between substituted and unsubstituted components of TTX was described by deformation and interaction energies. The substituent …
Rat liver preservation by hypothermic oscillating liver perfusion compared to simple cold storage.
1998
Rat livers were preserved hypothermically for 10 or 24 h in vitro as if for transplantation. Two methods of preservation were compared using physiological and biochemical parameters: simple storage and oscillating perfusion. By measuring the nucleotides after preservation the calculated energy charge was significantly higher after 10 and 24 h of oscillating perfusion compared to the simple storage group. In addition, a significant energy charge loading was demonstrated by 10 h oscillating perfusion compared to the initial value prior to perfusion. The oscillating, computer-controlled perfusion permits continuous monitoring of perfusate temperature, O2 consumption, pCO2, portal vein pressure…
Hypothermic Oscillating Liver Perfusion Stimulates ATP Synthesis prior to Transplantation
1998
Abstract Background. ATP and glycogen depletion often have been demonstrated during cold storage of the liver prior to transplantation. Suppression of events that lead to metabolic depression and to lipid peroxidation could contribute to improvement of liver preservation. A new method of liver preservation for transplantation is therefore suggested, an oscillating oxygenated hypothermic liver perfusion. Methods. Biochemical analysis of liver tissue samples and perfusate after 10 h of perfusion by the presented oscillating perfusion model were compared with results after continuous liver perfusion for 10 h as well as with data derived from cold-stored livers over a period of 10 h. Particular…
Protective action of 1,3-butanediol in cerebral ischemia. A neurologic, histologic, and metabolic study.
1987
1,3-Butanediol (BD) is converted in the body to β-hydroxybutyrate, and previous studies have shown that hyperketonemia had beneficial effects in experimental models of generalized hypoxia. The aim of this study was to determine if BD would reduce brain damage following cerebral ischemia. A transient forebrain ischemia of 30-min duration was induced by the four-vessel occlusion technique in control and BD-treated rats (25 mmol/kg, i.p.; 30 min prior to ischemia). BD treatment led to significant improvement of neurologic deficit during the 72-h recovery period and reduced neuronal damage in the striatum and cortex but not in the CA1 sector of the hippocampus. Evaluation of cerebral energy me…
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…
REDUCED OXIDATIVE STRESS DURING ACELLULAR REPERFUSION OF THE RAT LIVER AFTER HYPOTHERMIC OSCILLATING PERFUSION
1999
Background ATP resynthesis during reperfusion after liver preservation has been shown to be well correlated with the function of transplanted grafts. Nevertheless, the advantages of a cellular energy charge loading during the preservation period are yet not fully understood. This study evaluates the effects of different nucleotide levels at the end of preservation on metabolic changes and oxidative stress during reperfusion. Methods Two experimental groups were chosen reflecting different energy charge states after preservation: static cold storage for 10 hr and hypothermic oxygenated oscillating perfusion for 10 hr. In both experimental groups, normothermic ex vivo acellular reperfusion ov…
Is there a critical tissue oxygen tension for bioenergetic status and cellular pH regulation in solid tumors?
1996
Bioenergetic and metabolic status have been correlated with tissue oxygenation in murine fibrosarcomas (FSaII) of varying sizes (44-600 mm3). Ratios of beta-nucleoside triphosphates to inorganic phosphate (beta NTP/P) and phosphocreatine to inorganic phosphate (PCr/P(i)) ratios derived from 31P nuclear magnetic resonance spectroscopy (NMR) were positively correlated to median tissue O2 tension (pO2) values using O2-sensitive needle electrodes. pH declined during growth with intracellular acidosis being evident in tumors350 mm3. Whereas lactic acid formation greatly contributed to this decline in small and medium-sized tumors, adenosine triphosphate (ATP) hydrolysis and slowing down of the a…
Energy metabolism and intracellular pH in boar spermatozoa
2003
The effect of energy metabolism on intracellular pH was studied in boar spermatozoa using nuclear magnetic resonance (NMR) spectroscopy and confocal microscopy with the pH-sensitive dye seminaphthorhodafluor (SNARF-1). Freshly ejaculated spermatozoa had a high adenylate energy charge (AEC=0.8), which decreased to 0.6 under aerobic conditions and to 0.2 under anaerobic conditions. Correspondingly, no ATP resonances but high AMP resonance were visible in (31)P-NMR-spectra of the spermatozoa. When an artificial oxygen buffer (Fluosol) and a purpose-built air supply system were used during (31)P-NMR data acquisition, ATP resonances reappeared whereas the AMP resonance disappeared. Boar spermato…