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S Thelin

Publications and source records attributed to S Thelin.

61 records · Page 4Linked to original sources
PubMed1987

Myocardial high-energy phosphates, lactate and pyruvate during moderate or severe normothermic ischemia in rat hearts perfused with phosphoenolpyruvate and ATP in cardioplegic solution.

Rat hearts were subjected to normothermic ischemia for 15 min (group I) or 30 min (group II). During the ischemic period the hearts were perfused twice with cardioplegic solution supplemented with 14.4 mM phosphoenolpyruvate (PEP) and/or 0.067 mM adenosine triphosphate (ATP), and at the end of ischemia they were freeze-clamped. The myocardial ATP content in group I fell to about 55% of normal values except in hearts supplemented with only PEP, which showed greater reduction. In group II the ATP fell to only about 5% of normal values, without significant differences between the subgroups Hearts supplemented with PEP alone or with combined PEP-ATP showed significantly higher levels of pyruvate than in hearts with only ATP supplementation or control hearts. The study thus demonstrated clear difference in ATP content between moderate and severe ischemic trauma. The high pyruvate levels after PEP supplementation indicate formation of pyruvate without concomitant lactate increase.

Adenine Nucleotides↗
PubMed1987

Interrelated effects of nucleoside mono- and triphosphates and phosphoenolpyruvate on rat hearts subjected to cardioplegic arrest at normothermia.

Supplementation with phosphoenolpyruvate (PEP) and ATP was previously found to enhance the protective effect of potassium cardioplegia on rat hearts subjected to extensive ischemic trauma (30 min at 37 degrees C) in the paracorporeal rat heart model. In the present experiments, the ischemia time was reduced to 20 min (37 degrees C). Ventricular work after ischemia was best in control rats with potassium cardioplegia only. Supplementing the cardioplegic solution with PEP and ATP (group I) resulted in significantly reduced postischemic ventricular work and increased efflux of the creatine kinase isoenzyme MB (CK-MB). The same result was obtained when adenosine monophosphate (AMP) was added to the supplementation (group II). When guanosine monophosphate (GMP) was added instead of AMP (group III), the negative effects of PEP and ATP in the cardioplegic solution were partly abolished. Plain potassium cardioplegia, without additives, nevertheless gave the best results. There were no significant intergroup differences in the myocardial content of adenine nucleotides. The results contrasted with those in the previous study of more protracted ischemic trauma (30 min at 37 degrees C) and possible explanations are discussed.

Adenosine Monophosphate↗
PubMed1987

Metabolic and functional effects of creatine phosphate in cardioplegic solution. Studies on rat hearts during and after normothermic ischemia.

Creatine phosphate is a precursor molecule for ATP synthesis, even under ischemic conditions. We investigated its functional and metabolic effects when added to cardioplegic solution. Rat hearts were subjected to normothermic ischemia for 15 or 30 min and then freeze-clamped. During ischemia there was gradual reduction of high-energy phosphates, but the hearts with creatine phosphate supplement showed higher myocardial content of ATP and of the creatine compound. Other hearts, subjected to 20 min of ischemia, were reperfused with blood for 40 min. Creatine phosphate supplementation resulted in better left ventricular isovolumic work during spontaneous activity, but in paced activity (400 beats/min) no significant differences were seen. After reperfusion, supplemented hearts showed a tendency to higher levels of ATP and creatine phosphate. In all three groups the hearts with cardioplegic supplement had significantly increased myocardial content of pyruvate without proportional lactate increase. The results indicate that creatine phosphate may be an effective constituent in cardioplegic solution.

Animals↗
PubMed1986

Enhanced protection of rat hearts during ischemia by phosphoenolpyruvate and ATP in cardioplegia.

The paracorporeal rat heart model was used to investigate the extent of myocardial protection by potassium cardioplegia supplemented with phosphoenolpyruvate (PEP) (14.4 mM) and ATP (0.067 mM) singly or in combination. Rat hearts were subjected to 30 minutes of ischemia at 37 degrees. They were subsequently reperfused for 40 minutes during which time the left ventricular isovolumic work was measured and blood samples were taken for creatine kinase isoenzyme MB (CK-MB) analysis. At the end of each experiment the hearts were freeze-clamped for later analyses of high energy phosphate compounds. Supplementation with PEP and ATP (Group I) and with only ATP (Group II) showed a significantly better left ventricular isovolumic work and a significantly higher adenylate charge potential (ACP). Supplementation with only PEP (Group III) resulted in significantly better left ventricular isovolumic work than the control group but significantly lower than groups I and II. There were no significant differences between the groups in regard to the CK-MB efflux. Supplementation with PEP and ATP in combination did not show any positive effect at 40 minutes of reperfusion over and above that which was achieved with ATP only.

Adenosine Triphosphate↗
PubMed1985

Metabolic and functional effects of phosphoenolpyruvate and adenosine triphosphate on rat hearts subjected to global ischemia.

The effect of phosphoenolpyruvate (PEP) and adenosine triphosphate (ATP) administered during ischemia was investigated, using the paracorporeal rat heart model. During 15 min of global ischemia the hearts were perfused twice with PEP and ATP (supplemented) or with NaCl only (non-supplemented). In hearts that were freeze-clamped after the ischemic period (group A), the myocardial content of high-energy phosphates showed only minor differences between hearts with and without supplemention. In the supplemented hearts there was increased myocardial content of pyruvate and, to some extent, of lactate, indicating that PEP was metabolized to pyruvate and partly to lactate. In groups B and C the hearts were reperfused for 40 min before freeze-clamping. The non-supplemented hearts showed higher energy content and better left ventricular performance and, concomitantly, the creatine kinase isoenzyme MB (CK-MB) efflux was less than for the supplemented hearts. A clear inverse relationship between left ventricular performance and CK-MB efflux indicated that CK-MB served as a marker of cell integrity. These results contrasted with previus finding of an unequivocally positive effect from PEP and ATP administration. Possible explanations are discussed.

Adenosine Triphosphate↗