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The signal transducer and activator of transcription (STAT) family are latent transcription factors involved in a variety of signal transduction pathways, including cell death cascades. STAT1 has been shown to have a crucial role in regulating cardiac cell apoptosis in the myocardium exposed to ischemia/reperfusion (I/R) injury. The free radical scavenger, tempol, is known to have cardioprotective properties, although little is known about the molecular mechanism(s) by which it acts. In the present study, we assessed the levels of phosphorylated STAT1 and STAT3 and examined whether tempol was able to affect STAT activation after in vivo cardiac I/R injury. We observed a reperfusion time-dependent increase in the tyrosine phosphorylation of STAT1 and STAT3 at residues 701 and 705, respectively. Here we show for the first time that tempol dramatically reduced STAT1 and 3 phosphorylation. The reduction in STAT1 and 3 phosphorylation was accompanied by a concomitant decrease in cellular malondialdehyde (MDA) levels. To verify the role of STAT1 in modulating the cardioprotective effect of tempol, rats were injected with the STAT1 activator, IFN-gamma, and tempol during I/R injury. We found that the presence of IFN-gamma abrogated the protective effects of tempol, suggesting that the protective effects of tempol may partly operate by decreasing the phosphorylation of STAT1. This study demonstrates that careful dissection of the molecular mechanisms that underpin I/R injury may reveal cardioprotective targets for future therapy.

Multisystem organ failure represents a major cause of mortality in intestinal ischemia and reperfusion (I/R), and oxidative stress plays a key role in its pathogenesis. Hypothermia is beneficial in I/R injury, but its effects on systemic oxidative stress have not been elucidated. The aim of this study was to evaluate the effects of moderate hypothermia on systemic oxidative stress after intestinal I/R injury. Anaesthetized adult rats (n = 10 per group) underwent 60 min of intestinal ischemia followed by 120 min of reperfusion or sham operation at normothermia (36 degrees C-38 degrees C) or moderate hypothermia (30 degrees C-32 degrees C). At sacrifice, ileum, liver, lungs, and kidneys were removed to determine the concentration of malondialdehyde (a marker of lipid peroxidation), reduced and oxidized glutathione (a major endogenous antioxidant), and glutathione redox state. Plasma malondialdehyde and nitrate plus nitrite (reflecting nitric oxide production) were also analyzed. A marked elevation of malondialdehyde was observed after I/R at normothermia in plasma, ileum, and lungs; however, hypothermia during I/R prevented this increase. I/R at normothermia caused a profound decrease in reduced glutathione and glutathione redox state in the ileum, but this was not observed in I/R at hypothermia. Interestingly, hypothermia increased glutathione content of control intestine. Nitric oxide production was increased only in normothermic I/R animals. Moderate hypothermia attenuates systemic oxidative stress associated with experimental intestinal I/R in an animal model by decreasing lipid peroxidation in plasma, ileum, lungs, and kidneys, by preventing the depletion of gut glutathione, and by reducing systemic nitric oxide production. However, whether these effects persist after rewarming is unknown.

Urokinase is an enzyme with a fibrinolytic effect that facilitates pleural empyema drainage through a chest tube. The aim of this study was to assess the risk of pneumothorax, the need for pleural debridement surgery, the persistence of fever, and the number of days in hospital in a group of children with parapneumonic pleural empyema treated with urokinase. This was an uncontrolled retrospective study on children suffering from parapneumonic empyema. Data collected on 17 children treated with urokinase were compared with 11 children treated prior to the advent of urokinase (the "historic" group). The urokinase was instilled in the pleural cavity over a period ranging from 2-8 days, amounting to a median total dose per kilogram of body weight of 18,556 IU (range, 7,105-40,299). Surgical treatment of the empyema involved drainage tube placement and/or debridement of the pleural cavity. Three children developed pneumothorax during their hospital stay, and one more case occurred 6 months after the child had recovered from his empyema; there were 3 cases of pneumothorax during the acute phase in the "historic" group (P = 0.54). Five children in the urokinase group were debrided and 12 were only drained, as opposed to 9 and 2, respectively, in the "historic" group (P = 0.02). The overall hospital stay was 17 days for the urokinase group, and 24 for the "historic" group (P = 0.02). No bleeding or other major complications were reported in the group treated with urokinase. In conclusion, urokinase treatment does not carry a risk of pneumothorax, while it does reduce hospital stay and the need for pleural debridement.