Changes in ECG and enzyme activity in rat heart after myocardial infarction: effect of TPP and MnCl2.

Heart infarction is one of the main causes of death in the human population. Assurance of a sufficient level of bioenergetic processes is very important for the heart after infarction. Mn2+ as well as thiamine pyrophosphate (TPP) are positive effectors of the pyruvate dehydrogenase complex (PDH) and the 2-oxoglutarate dehydrogenase complex (OGDH), both of which play a very important role in the Krebs cycle. Thus, we have established the effect of MnCl2 (10mg/kg) and TPP (20mg/kg)--4 injections every 12 h--on the activity of PDH, OGDH, lactate dehydrogenase (LDH) and malate dehydrogenase (MDH). Additionally, we perform an analysis of ECG to affirm the changes in the heart electrophysiology of healthy rats after MnCl2 and TPP treatment. We then analyzed changes in the activity of these enzymes after experimental myocardial infarction in rats. We observed a decrease of OGDH and MDH activity in rat hearts after infarction in comparison with sham-operated rats. Treatment of healthy rats with MnCl2 caused an increase of OGDH activity. Moreover both MnCl2 and TPP caused an increase of PDH activity and a decrease of MDH activity (TPP revealed a stronger effect). We found no changes in LDH activity. Electrocardiography data showed a slight shortening of the QT interval and an enhanced heartbeat rate after treatment with MnCl2. TPP caused only elongation of the QT interval. In conclusion, application of MnCl2 enhanced the activity of some very important enzymes in the respiration process (PDH and OGDH). This effect, connected with enhanced heartbeat and a slightly shortened ventricle relaxation, may have potential application during the key period of convalescence following heart infarction.

Changes in ECG and enzyme activity in rat heart after myocardial infarction: effect of TPP and MnCl2

Heart infarction is one of the main causes of death in the human population.Assurance of a sufficient level of bioenergetic processes is very important for theheart after infarction. Mn2+ as well as thiamine pyrophosphate (TPP) are positiveeffectors of the pyruvate dehydrogenase complex (PDH) and the 2-oxoglutaratedehydrogenase complex (OGDH), both of which play a very important role in theKrebs cycle. Thus, we have established the effect of MnCl2 (10mg/kg) and TPP(20mg/kg) - 4 injections every 12 h - on the activity of PDH, OGDH, lactate dehydrogenase(LDH) and malate dehydrogenase (MDH). Additionally, we perform ananalysis of ECG to affirm the changes in the heart electrophysiology of healthy ratsafter MnCl2 and TPP treatment. We then analyzed changes in the activity of theseenzymes after experimental myocardial infarction in rats. We observed a decrease ofOGDH and MDH activity in rat hearts after infarction in comparison with shamoperatedrats. Treatment of healthy rats with MnCl2 caused an increase of OGDHactivity. Moreover both MnCl2 and TPP caused an increase of PDH activity and adecrease of MDH activity (TPP revealed a stronger effect). We found no changes inLDH activity. Electrocardiography data showed a slight shortening of the QT intervaland an enhanced heartbeat rate after treatment with MnCl2. TPP caused onlyelongation of the QT interval. In conclusion, application of MnCl2 enhanced theactivity of some very important enzymes in the respiration process (PDH andOGDH). This effect, connected with enhanced heartbeat and a slightly shortenedventricle relaxation, may have potential application during the key period of convalescencefollowing heart infarction (AU)

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Effect of brefeldin A on membrane localization of MUC1 mucin and adhesive properties of cancer cells.

Transmembrane glycoproteins play a significant role in cancer cells adhesion and metastatic process, just for that reason the glycosylation inhibitors are used to change the glycan structure and in this way the membrane expression of glycoproteins. The inhibitory effect of brefeldin A (BFA) on the expression of some glycoproteins: MUC1 mucin and alpha2beta1 integrin on cell surface of breast (MCF-7 and MDA-MB-231 lines) and endometrial (Ishikawa line) cancer cells was evaluated in our study. In MCF-7 and MDA-MB-231 cells, a decrease in MUC1 expression depended on brefeldin A concentration and equaled about 40% in cells treated with 1mg% of drug. In Ishikawa cells, a decrease in MUC1 expression was lower and amounted to about 25%. The expression of alpha2beta1 integrin was greatly inhibited in brefeldin-treated MCF-7 and Ishikawa cells, though it was unchanged in MDA-MB-231 cells. A decrease in MUC1 mucin and alpha2beta1 integrin level reduced the adhesive properties of BFA-treated cells. Adhesion to type I collagen was greatly diminished in BFA-treated MCF-7 and Ishikawa cells (above 70%), and to a lesser degree in MDA-MB-231 cells (about 50%); which was mainly caused by the inhibited integrin expression. These findings have proved that brefeldin A, by changing the surface glycoproteins level, can alter carcinoma cells adhesion to extracellular matrix proteins.

[Application of thermosetting plastics to eliminate undercuts]. / Zastosowanie tworzyw termoutwardzalnych do likwidacji podcieni.

The author proposes to utilize the properties of thermosetting plastics used in other fields to use them in prosthetics in order to eliminate undercuts. Application of extra equipment in claspograph in the form of studs of three dimension makes formation of undercuts' blockade easier improving the result of work at the same time.