Expression of inducible nitric oxide synthase in muscle flaps treated with ischemic postconditioning

Activation of endoplasmic reticulum stress in rat brain following low-intensity microwave exposure

The present study was designed to explore the effects of low-intensity microwave radiation on endoplasmic reticulum stress and unfolded protein response. Experiments were performed on male Wistar rats exposed to microwave radiation for 30 days at 900 MHz, 1800 MHz, and 2450 MHz frequencies on four groups of animal: sham-exposed group, 900 MHz exposed (SAR 5.84 × 10^-4 W/kg), 1800 MHz exposed (SAR 5.94 × 10^-4 W/kg), and 2450 MHz exposed (SAR 6.7 × 10^-4 W/kg) groups. Expressions of mRNA were estimated at the end of exposure in rat brain by real-time quantitative PCR. Microwave exposure at 900, 1800, and 2450 MHz with respective SAR values as mentioned above significantly (< 0.05) altered mRNA expression of transcription factors ATF4, CHOP, and XBP1 in accordance with increasing microwave frequency. The result of the present study reveals that low-intensity microwave exposure at frequencies 900, 1800, and 2450 MHz induces endoplasmic reticulum stress and unfolded protein response.

Ischemic Postconditioning and Nitric Oxide Administration Failed to Confer Protective Effects in a Porcine Model of Extracorporeal Cardiopulmonary Resuscitation

The protective effects of ischemic postconditioning (IPC) and nitric oxide (NO) administration have been demonstrated in several ischemic scenarios. However, current evidence regarding the effect of IPC and NO in extracorporeal cardiopulmonary resuscitation remains lacking. Fifteen female swine (body weight 45 kg) underwent veno-arterial extracorporeal membrane oxygenation (ECMO) implantation; cardiac arrest-ventricular fibrillation was induced by rapid ventricular pacing. After 20 min of cardiac arrest, blood flow was restored by increasing the ECMO flow rate to 4.5 L/min. The animals (five per group) were then randomly assigned to receive IPC (three cycles of 3 min ischemia and reperfusion), NO (80 ppm via oxygenator), or mild hypothermia (HT; 33.0°C). Cerebral oximetry and aortic blood pressure were monitored continuously. After 90 min of reperfusion, blood samples were drawn for the measurement of troponin I, myoglobin, creatine-phosphokinase, alanine aminotransferase, neuron-specific enolase, cystatin C, and reactive oxygen metabolite (ROM) levels. Significantly higher blood pressure and cerebral oxygen saturation values were observed in the HT group compared with the IPC and NO groups (P < 0.05). The levels of troponin I, myoglobin, creatine phosphokinase, and alanine aminotransferase were significantly lower in the HT group (P < 0.05); levels of neuron-specific enolase, cystatin C, and ROM were not significantly different. IPC and NO were comparable in all monitored parameters. The results of the present study indicate that IPC and NO administration are not superior interventions to HT for the maintenance of blood pressure, cerebral oxygenation, organ protection, and suppression of oxidative stress following extracorporeal cardiopulmonary resuscitation.