Role of activated protein C on wound healing process in left colonic anastomoses in the presence of intra-abdominal sepsis induced by cecal ligation and puncture: An experimental study in the rat

Background: Activated protein C (APC) is a serine protease with anticoagulant and anti-inflammatory activities. The delaying effects of intra-abdominal sepsis on wound healing process in colonic anastomoses have been previously demonstrated. This study was designed to investigate the role of APC on wound healing process in left colonic anastomoses in the presence of intra-abdominal sepsis. Methods: The left colonic anastomosis was performed in 48 rats that were divided into four groups: (1) sham-operated group, laparatomy plus cecal mobilization (n = 12); (2) sham + APC group, identical to group I except for APC treatment (n = 12); (3) CLP group, cecal ligation and puncture (n = 12); 4) CLP + APC-treated group, 100 µg/kg, 15 min before the construction of colonic anastomosis (n = 12). Anastomotic bursting pressures were measured in vivo on day 7. Tissue samples were obtained for analyses of hydroxyproline (HP) contents, myeloperoxidase (MPO) acivity, malondialdehyde (MDA), and nitrate/nitrite (NO 3 - /NO 2 - ) levels. The plasma levels of tumor necrosis factor ? (TNF-?), interleukin (IL)-6, and D-dimer also were measured. Results: Intra-abdominal sepsis led to significant decreases in colonic anastomotic bursting pressures and tissue HP contents, along with increases in MPO activity, MDA and NO 3 - /NO 2 - levels, and also plasma levels of TNF-?, IL-6, and D-dimer (P ;lt; 0.05). However, APC treatment led to significant increases in anastomotic bursting pressures and tissue HP ontents, along with decreases in MPO activity, MDA and NO 3 - /NO 2 - levels, and also plasma levels of TNF-?, IL-6, and D-dimer (P ;lt; 0.05). Conclusions: This study clearly showed that APC treatment prevented the delaying effects of intra-abdominal sepsis on colonic anastomotic wound healing process. Further clinical studies are required to determine whether APC has a useful role in the enhancement of anastomotic healing during particular surgeries in which sepsis-induced injury occurs. © 2008 Société Internationale de Chirurgie

Activated Protein C Attenuates Intestinal Mucosal Injury After Mesenteric Ischemia/Reperfusion

Background: Activated protein C (APC) is a serine protease with anticoagulant and ant-inflammatory activities. APC has been shown to attenuate deleterious effects of ischemia/reperfusion (I/R) injury in many organs. In this study, we aimed to investigate the effects of APC on intestinal mucosal injury induced by superior mesenteric occlusion. Materials and Methods: Male Wistar-albino rats were allocated into four groups: (1) sham-operated group, laparotomy without I/R injury (n = 12); (2) sham + APC group, identical to Group 1 except for APC treatment (n = 12); (3) I/R group, 60 min of ischemia followed by 3-h of reperfusion (n = 12); and (4) I/R + APC-treated group, 100 µg/kg injection of APC intravenously, 15 min before reperfusion (n = 12). We evaluated the degree of intestinal mucosal injury on a grading scale from 0 to 5, histopathologically, and by measuring activities of oxidative and antioxidative enzymes as well as nitrate/nitrite levels, biochemically. Intestinal edema was estimated by using wet/dry weight ratios. The plasma levels of proinflammatory cytokines and D-dimer were measured. Animal survival was observed up to 1 wk. Results: Intestinal mucosal injury scores were significantly decreased with APC administration (P 0.05). APC treatment significantly reduced activities of oxidative enzymes and nitrate/nitrite levels in the intestinal tissues, and plasma levels of proinflammatory cytokines and D-dimer, and also significantly increased activities of antioxidative enzymes in the intestinal tissues (P 0.05). Intestinal edema was significantly alleviated with APC treatment (P 0.05). The survival rate of rats in the APC-treated group were significantly higher than that of the I/R-treated group (P 0.05). Conclusions: This study clearly showed that APC treatment significantly attenuated intestinal mucosal injury caused by superior mesenteric ischemia/reperfusion. Further clinical studies are required to clarify whether APC has a useful role in reperfusion injury during particular surgeries in which I/R-induced organ injury occurs. © 2008 Elsevier Inc. All rights reserved

Activated protein C attenuates intestinal reperfusion-induced acute lung injury: an experimental study in a rat model

Background: Activated protein C (APC) is a serine protease with anticoagulant and anti-inflammatory activities. APC has been shown to attenuate local deleterious effects of ischemia/reperfusion (I/R) injury in many organs. We aimed to investigate the effects of APC on lung reperfusion injury induced by superior mesenteric occlusion. Methods: Male Wistar-Albino rats were allocated into 4 groups: (1) sham-operated group, laparotomy without I/R injury (n = 12); (2) sham + APC group, identical to group 1 except for APC treatment (n = 12); (3) intestinal I/R group, 60 minutes of ischemia followed by 3 hours of reperfusion (n = 12); and (4) I/R + APC-treated group, 100 μg/kg injection of APC intravenously, 15 minutes before reperfusion (n = 12). Evans blue dye was injected into half of the rats in all groups. We assessed the degree of pulmonary tissue injury by measuring activities of oxidative and antioxidative enzymes, as well as nitrate (NO3-)/nitrite (NO2-) levels, biochemically. We evaluated acute lung injury (ALI) by establishing pulmonary neutrophil sequestration and ALI scoring histopathologically. Pulmonary edema was estimated by using Evans blue dye extravasation and wet/dry ratios. The plasma levels of proinflammatory cytokines and D-dimer were measured. Results: APC treatment significantly reduced activities of oxidative enzymes and nitrate/nitrite levels in the lung tissues, and plasma levels of proinflammatory cytokines and D-dimer, and also significantly increased activities of antioxidative enzymes (P < .05). Pulmonary neutrophil sequestration and ALI scores were decreased significantly with APC administration (P < .05). In addition, APC treatment significantly alleviated pulmonary edema (P < .05). Conclusions: This study clearly showed that APC treatment significantly attenuated the lung reperfusion injury. Further clinical studies are required to clarify whether APC has a useful role in the reperfusion injury during particular surgeries in which I/R-induced organ injury occurs. © 2008 Elsevier Inc. All rights reserved

Polarization and spectral energy distribution in OJ 287 during the 2016/17 outbursts

We report optical photometric and polarimetric observations of the blazar OJ 287 gathered during 2016/17. The high level of activity, noticed after the General Relativity Centenary flare, is argued to be part of the follow-up flares that exhibited high levels of polarization and originated in the primary black hole jet. We propose that the follow-up flares were induced as a result of accretion disk perturbations, travelling from the site of impact towards the primary SMBH. The timings inferred from our observations allowed us to estimate the propagation speed of these perturbations. Additionally, we make predictions for the future brightness of OJ 287. © 2017 by the authors

Stochastic Modeling of Multiwavelength Variability of the Classical BL Lac Object OJ 287 on Timescales Ranging from Decades to Hours

We present the results of our power spectral density analysis for the BL Lac object OJ 287, utilizing the Fermi-LAT survey at high-energy γ-rays, Swift-XRT in X-rays, several ground-based telescopes and the Kepler satellite in the optical, and radio telescopes at GHz frequencies. The light curves are modeled in terms of continuous-time autoregressive moving average (CARMA) processes. Owing to the inclusion of the Kepler data, we were able to construct for the first time the optical variability power spectrum of a blazar without any gaps across ∼6 dex in temporal frequencies. Our analysis reveals that the radio power spectra are of a colored-noise type on timescales ranging from tens of years down to months, with no evidence for breaks or other spectral features. The overall optical power spectrum is also consistent with a colored noise on the variability timescales ranging from 117 years down to hours, with no hints of any quasi-periodic oscillations. The X-ray power spectrum resembles the radio and optical power spectra on the analogous timescales ranging from tens of years down to months. Finally, the γ-ray power spectrum is noticeably different from the radio, optical, and X-ray power spectra of the source: we have detected a characteristic relaxation timescale in the Fermi-LAT data, corresponding to ∼150 days, such that on timescales longer than this, the power spectrum is consistent with uncorrelated (white) noise, while on shorter variability timescales there is correlated (colored) noise. © 2018. The American Astronomical Society. All rights reserved.