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Erythropoietin (EPO), an essential hormone for erythropoiesis, can provide protection against myocardial ischemia/reperfusion (I/R) injury and hypoxic apoptosis. GATA-4 is a zinc finger transcription factor, and its activation and post-translational modification are essential components in the transcriptional response to hypoxia. GATA-4 has also been reported to play a role in the cellular mechanisms of EPO-induced myocardial protection against I/R injury. In this study, we aimed to investigate the influence of EPO on GATA-4 protein stability and post-translational modification under hypoxic conditions without reperfusion. EPO induced cell viability under long-term hypoxia. EPO significantly increased phosphorylation of GATA-4 via the extracellular signal-regulated kinase (ERK) signaling pathway and reduced hypoxia-induced GATA-4 ubiquitination, which enhanced GATA-4 stability under hypoxia. ERK activation by over-expression of constitutively active mitogen-activated protein kinase 1 (MEK1) strongly increased GATA-4 phosphorylation and its protein levels and decreased GATA-4 ubiquitination under hypoxia. Despite ERK activation, GATA-4 ubiquitination was not affected under hypoxia in a GATA-4-S105A mutant. Under hypoxic condition without reperfusion, EPO-induced ERK activation was associated with post-translational modification of GATA-4, mediated by enhancement of phosphorylation of GATA-4 at Ser-105. Subsequent attenuation of GATA-4 ubiquitination led to increases in GATA-4 protein stability, which resulted in increased cell viability under hypoxia.

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dione) was successfully synthesized via Horner-Emmons condensation. The polymer showed a low bandgap energy (E g = 1.56 eV) in a film state. The polymer also exhibits good solubility in common organic solvents and good self-film-forming properties. The semiconducting properties of the polymer synthesized herein were evaluated in organic thin film transistors (OTFTs). The polymer exhibits charge carrier mobilities as high as 3.0 × 10 −3 cm 2 V −1 s −1 (I on/off = 10 5 ) after thermal annealing at 200 • C for 10 min, which is three times higher than that of thin film transistor made of the pristine film.

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Background:This study was designed to compare the effect of low-molecular 6% hydroxyethyl starch (HES) 130/0.4 on hemostasis and hemodynamic efficacy with that of medium-molecular 6% HES 200/0.5 in patients undergoing off-pump coronary artery bypass surgery.Methods: Forty-eight patients were randomized to receive up to 33 ml/kg of either 6% HES 130/0.4 or 6% HES 200/0.5. Hemodynamic variables and blood tests including thromboelastography were measured 10 min after induction (baseline value, T0), 5 min after acute loading of HES 10 ml/kg (T1) in hypovolemic patients, after sternum closure (T2), and 16 hr after intensive care unit (ICU) arrival (T3). Chest tube drainage was recorded until 16 hours after ICU arrival.Results: Hemodynamic variables were similar in both groups. Chest tube drainage at 16 hr after surgery was higher in HES 200/0.5 group than that in HES 130/0.4 group. Maximum clot firmness was decreased in HES 200/0.5 group at sternal closure but not in HES 130/0.4 group.Conclusions: Both HES 200/0.5 and HES 130/0.4 were equally efficient in maintaining stable hemodynamics during off-pump coronary artery bypass surgery. However, HES 130/0.4 may reduce postoperative blood loss compared to that of HES 200/0.5 at the same dose of 33 ml/kg. (Korean J Anesthesiol 2007; 53: S 14～21)

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