U. Oral

The protective effect of N-acetylcysteine on apoptotic lung injury in cecal ligation and puncture-induced sepsis model.

Apoptotic loss of parenchymal cells may lead to organ dysfunctions in critically ill patients with septic states. As an antioxidant, the protective effects of N-acetylcysteine (NAC) are documented in many experimental and clinical studies. In this experimental study, we investigated the role of chronically used NAC in septic lung injury on a cecal ligation and puncture (CLP) model. To evaluate this, 30 male Wistar rats were randomly divided into four groups as sham (n = 7), CLP (n = 8), sham + NAC (n = 7) and CLP + NAC (n = 8) groups. NAC was administered 150 mg kg−1 day through intramuscular route beginning 6 h after the operations and lasting for a period of 1 week. One week later, histopathology and epithelial apoptosis were assessed by hematoxylin-eosin and immunohistochemically by M30 and caspase 3 staining to demonstrate septic lung injury. Additionally, lung tissue myeloperoxidase (MPO) activity, malondialdehyde (MDA), and nitrite/nitrate levels were measured. The MPO activity and MDA levels in lung homogenates were found to be increased in CLP group and the administration of NAC prevented their increase significantly (P < 0.05). However, there were no significant differences among the groups regarding nitrite/nitrate levels. The number of apoptotic cells was significantly lower in CLP+NAC group than CLP group, and this finding was supported by M30 and caspase 3 expression in lung (P < 0.05). Lung histopathology was also protected by NAC in CLP-induced sepsis. In conclusion, the chronic use of NAC inhibited MPO activity and lipid peroxidation, which resulted in reduction of apoptosis in lung in this CLP model. Because lung tissue nitrite/nitrate levels did not change significantly, organs other than the lungs may be responsible for producing the increased nitric oxide during sepsis. The chronic use of NAC needs further investigation for its possible antiapoptotic potential in septic states besides its documented antioxidant and antiinflammatory effects.

Liver and kidney toxicity in chronic use of opioids: An experimental long term treatment model

In this study, histopathological and biochemical changes due to chronic usage of morphine or tramadol in liver and kidney were assessed in rats. Thirty male Wistar rats (180–220 g) were included and divided into three groups. Normal saline (1 ml) was given intraperitoneally as placebo in the control group (n = 10). Morphine group (n = 10) received morphine intraperitoneally at a dose of 4, 8, 10 mg/kg/day in the first, second and the third ten days of the study, respectively. Tramadol group (n = 10), received the drug intraperitoneally at doses of 20, 40 and 80 mg/kg/day in the first, second and the third ten days of the study, respectively. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), creatinin, blood urea nitrogen (BUN) and malondialdehyde (MDA) levels were measured in the serum. Liver and kidney specimens were evaluated by light microscopy. Serum ALT, AST, LDH, BUN and creatinin levels were significantly higher in morphine group compared to the control group. Serum LDH, BUN and creatinin levels were significantly increased in the morphine group compared to the tramadol group. The mean MDA level was significantly higher in morphine group compared to the tramadol and control groups (P<0.05). Light microscopy revealed severe centrolobular congestion and focal necrosis in the liver of morphine and tramadol groups, but perivenular necrosis was present only in the morphine group. The main histopathologic finding was vacuolization in tubular cells in morphine and tramadol groups. Our findings pointed out the risk of increased lipid peroxidation, hepatic and renal damage due to long term use of opioids, especially morphine. Although opioids are reported to be effective in pain management, their toxic effects should be kept in mind during chronic usage

Intestinal ischemic preconditioning protects the intestine and reduces bacterial translocation.

Ischemic preconditioning (IPC) was first demonstrated in the heart, but this protective effect has been also recently described in the intestine. The aim of this study was to determine the effects of intestinal ischemic preconditioning on the morphology of intestine and bacterial translocation. Twenty-four male Wistar rats weighting 250 to 300 g were randomized into three groups. A control group of rats (n = 8) were subjected laparotomy. In an ischemic group (n = 8), laparotomy was performed and the superior mesenteric artery was occluded by an atraumatic clamp for 30 min. In the preconditioned group (n = 8), before the ischemia-reperfusion (I/R) period (as in ischemic group), rats were subjected to an initial 10 min of intestinal ischemia and 10 min of reperfusion. Twenty-four hours later, to evaluate whether the I/R induced intestinal injury and bacterial translocation (BT), tissue and blood samples were collected, and liver, spleen, and mesenteric lymph node specimens were obtained under sterile conditions for microbiological analysis. Samples of ileum were removed for both biochemical and histopathological evaluation. In the I/R group, the incidence of bacteria-isolated mesenteric lymph nodes, spleen, liver, and blood was significantly higher than other groups (P < 0.05). IPC prevented I/R-induced BT and it significantly reduced the I/R-induced intestinal injury (P < 0.05). Increased inducible nitric oxide (NO) synthase (iNOS) expression observed on the ileal specimens of the I/R group was found to be prevented by IPC. Our data suggest IPC as a key factor that reduces BT and iNOS activation in intestinal I/R. This is the first study showing that intestinal IPC blocks the cascade of events that causes BT and intestinal injury that may lead to sepsis.

OPIOID NEUROTOXICITY: COMPARISON OF MORPHINE AND TRAMADOL IN AN EXPERIMENTAL RAT MODEL

Histopathologic changes in rat brain due to chronic use of morphine and/or tramadol in progressively increased doses were investigated in this study. Thirty male Wistar rats (180-220 g) were included and divided into three groups. Normal saline (1 ml/kg) was given intraperitoneally as placebo in the control group (n = 10). Morphine group (n = 10) received morphine intraperitoneally at a dose of 4 mg/kg/day for the first 10 days, 8 mg/kg/day between 11-20 days, and 12 mg/kg/day between 21-30 days. The tramadol group (n = 10) received the drug intraperitoneally at doses of 20, 40, and 80 mg/kg/day in the first, second, and the third 10 days of the study, respectively. All rats were decapitated on the 30th day and the brain was removed intact for histology. The presence and the number of red neurons, which are a histologic marker of apoptosis, were investigated in the parietal, frontal, temporal, occipital, entorhinal, pyriform, and hippocampal CA1, CA2, CA3 regions. Red neurons were found in morphine and tramadol groups but not in the control group. The total number of red neurons was not different in morphine and tramadol groups, but the numbers of red neurons were significantly higher in the temporal and occipital regions in tramadol group as compared with the morphine group (p < .05). In conclusion, chronic use of morphine and/or tramadol in increasing doses is found to cause red neuron degeneration in the rat brain, which probably contributes to cerebral dysfunction. These findings should be taken into consideration when chrome use of opioids is indicated.

N-Acetylcysteine for Preventing Pump-Induced Oxidoinflammatory Response During Cardiopulmonary Bypass

PurposeTo investigate the effect of N-acetylcysteine on preventing pump-induced oxidoinflammatory response during cardiopulmonary bypass (CPB).MethodsForty patients undergoing coronary artery bypass grafting (CABG) were randomly divided into a study group (n = 20), given 50 mg kg−1N-acetylcysteine intravenously for 3 days, and a control group (n = 20) given saline. Serum samples were collected for measurement of myeloperoxidase (MPO), malondialdehyde (MDA), interleukin-6, Α1-acid glycoprotein (AAGP), and C-reactive protein (CRP) during surgery and postoperatively.ResultsThe MPO and MDA values showed a similar pattern during and after CPB in the study group, with significantly less variance than in the control group. Interleukin-6 showed similar patterns in the two groups, but the data from 30 min after the start of CPB and from 6 h post-CPB were significantly different. The AAGP and CRP values were both elevated during CPB in the two groups without a significant difference, but 6 and 24 h post-CPB, the values were significantly higher in the control group than in the study group.ConclusionsN-Acetylcysteine decreased pump-induced oxidoinflammatory response during CPB, suggesting that it could be a novel therapy for assisting in the prevention of CBP-induced oxidoinflammatory damage.

Ischemic preconditioning reduces intestinal epithelial apoptosis in rats.

Recent experimental studies have described protective effect of ischemic preconditioning (IPC) on ischemia–reperfusion (I/R) injury of the intestine. We hypothesize that to reach a new point of view on the effect of IPC in intestinal barrier function, the relationship between I/R-induced mucosal injury and apoptosis must first be clarified. The present study was undertaken to investigate the role of IPC on intestinal apoptosis and probable contributions of bcl-2 expression to this process. We also investigated the effect of intestinal IPC on ileal malondyaldihyde levels. Forty-four male Wistar rats were randomized into four groups each consisting of 11 rats: sham-operated control, I/R group (30 min of superior mesenteric artery occlusion), IPC-I/R group (10 min of temporary artery occlusion prior before an ischemic insult of 30 min), and IPC alone group (10 min of preconditioning). Twenty-four hours later, ileum samples were obtained. Ileal malondyaldihyde levels were increased in the I/R group (31.9 ± 18.8 vs. 106.8 ± 39.8) but not in the IPC alone and IPC-I/R groups (38.1 ± 13.6 and 44.7 ± 12.7;P < 0.01). The number of apoptotic cells was significantly lower in IPC-I/R group than that of I/R group, and these findings were further supported by DNA laddering and M30 findings. Diminished bcl-2 expression observed in the ileal specimens of I/R group was prevented by IPC. Our results indicate that IPC may provide a protective effect on ileal epithelium and that this effect is probably the result of a significant increase in the expression of bcl-2 after the insult. The reversal of apoptosis by IPC might help preserving the vitality of intestinal structures that have a critical function, cessation of which often leads to multiorgan dysfunction syndrome.

Efficacy of tramadol versus meperidine for pain relief and safe recovery after adenotonsillectomy.

Background and objective: Adequate relief of pain after tonsillectomy is a common problem. We compared meperidine and tramadol when given at induction of anaesthesia with respect to their effects on postoperative pain relief and emergence characteristics after adenotonsillectomy in children. Methods: Fifty children aged 4-7 yr undergoing tonsillectomy were randomly assigned to receive either tramadol 1 mg kg−1 (n = 25) or meperidine 1 mg kg−1 (n = 25) before commencement of the surgical procedure. Anaesthesia was induced with propofol (with cis-atracurium for muscle relaxation) and maintained with sevoflurane in oxygen and nitrous oxide. Postoperative pain was scored by a blinded observer using a facial pain scale in the recovery room at 0 (at arrival of the patient in the postoperative care unit) and at 10, 20 and 45 min thereafter. Agitation scores were also assessed by the same observer at 0 min. Heart rate and mean arterial pressure were recorded at regular intervals. The time to recovery to spontaneous respiration and the incidence of postoperative nausea and vomiting were noted. Results: Facial pain scale scores were increased in the tramadol group at 0, 10 and 20 min (P < 0.05). No difference was observed in scores at the 45th min postoperation. Agitation scores were higher in the tramadol group than in the meperidine group. No statistical difference was found between the two groups. Heart rates and mean arterial pressures were similar in both groups. The time to recovery to spontaneous respiration was delayed with meperidine compared with tramadol (P < 0.05). The incidence of nausea and vomiting was not statistically different between groups. Conclusions: Meperidine was more effective for pain relief and provides better emergence characteristics than tramadol after tonsillectomy in children.

The comparison of the efficacy of scoring systems in organophosphate poisoning

The purpose of this study was to evaluate the impact of the Glasgow Coma Scale (GCS), Acute Physiology and Chronic Health Evaluation (APACHE) II and Simplified Acute Physiology Score (SAPS) II scoring systems for organophosphate poisoning (OPP) in an intensive care unit (ICU). The following data were collected on all consecutive patients who were admitted to the ICU between June 1999 and December 2004. Demographic data, GCS, APACHE II and SAPS II scoring systems were recorded. Predicted mortality was calculated using original regression formulas. Standardized mortality ratio (SMR) was computed with 95% confidence intervals (CI). The sensitivity and specificity for each scoring system were evaluated by calculating the Area Under the Receiver Operating Characteristic Curves. The actual mortality in OPP was 21.9%. Predicted mortality by all systems was not significantly different from actual mortality [SMR and 95% CI for GCS: 1.00 (0.65-1.35), APACHE II: 0.87 (0.54-1.03), SAPS II: 1.40 (0.98-1.82)]. The area under the ROC curve for APACHE II is largest, but there is no statistically significant difference when compared with SAPS II and GCS (GCS 0.9009 / 0.059, APACHE II 0.9299 / 0.045 and SAPS II 0.8919 / 0.057). In our ICU group of patients, in predicting the mortality rates in OPP, the three scoring systems, which are GCS, APACHE II and SAPS II, had similar impacts; however, GCS system has superiority over the other systems in being easy to perform, and not requiring complex physiologic parameters and laboratory methods.

THE ROLE OF POLY(ADP-RIBOSE) SYNTHETASE INHIBITION IN PREVENTING ENDOTOXEMIA-INDUCED INTESTINAL EPITHELIAL APOPTOSIS

In this lipopolysaccharide (LPS)-induced endotoxemia model, the effects of 3-aminobenzamide (3-AB), a poly(ADP-ribose) synthetase (PARS) inhibitor, on ileal apoptosis were evaluated by light microscopy and M30 cell death staining. Moreover, the relationship between Bcl-2, iNOS expression, and serum nitrate (NO(3)(-)) levels were investigated. Thirty-two male Wistar rats, weighing 180-220g were randomly divided into four groups. The group I (control; n=8) received saline and group II (sepsis; n=8) received 10 mg kg(-1) LPS intraperitoneally. 3-AB was given to the group IV (S+3-AB; n=8) 20 min before giving LPS and to the group III (C+3-AB; n=8) 20 min before giving saline. Six hours later, blood and ileum samples were taken. Endotoxemic group exhibited significant apoptosis in intestinal epithelial cells and the immunohistochemical examination with M30 was demonstrated that the 3-AB reduced the LPS-induced intestinal apoptosis. Serum NO(3)(-) level was increased in endotoxemic group, whereas the elevation of NO(3)(-) level was prevented in LPS+3-AB group (P<0.05). The increased iNOS expression observed in the LPS group was also prevented by 3-AB. Compared with the endotoxemic group, ileal epithelial columnar cells from LPS+3-AB group had a dense Bcl-2 staining which was almost identical with control. In conclusion, 3-AB decreases LPS-induced apoptosis in ileum by preventing LPS-induced depletion of Bcl-2 and blocking iNOS gene. Modification of Bcl-2 expression by PARS inhibitors should further be investigated as a new therapeutic alternatives in septic states.

Effects of levosimendan on myocardial ischaemia-reperfusion injury

Background and objective: Levosimendan has a cardioprotective action by inducing coronary vasodilatation and preconditioning by opening KATP channels. The aim of this study was to determine whether levosimendan enhances myocardial damage during hypothermic ischaemia and reperfusion in isolated rat hearts. Methods: Twenty‐one male Wistar rats were divided into three groups. After surgical preparation, coronary circulation was started by retrograde aortic perfusion using Krebs‐Henseleit buffer solution and lasted 15 min. After perfusion Group 1 (control; n = 7) received no further treatment. In Group 2 (non‐treated; n = 7), hearts were arrested with cold cardioplegic solution after perfusion and subjected to 60 min of hypothermic global ischaemia followed by 30 min reperfusion. In Group 3 (levosimendan treated; n = 7), levosimendan was added to the buffer solution during perfusion and the hearts were arrested with cold cardioplegic solution and subjected to 60 min of hypothermic global ischaemia followed by 30 min reperfusion. At the end of the reperfusion period, the hearts were prepared for biochemical assays and for histological analysis. Results: Tissue malondialdehyde levels were significantly lower in the levosimendan‐treated group than in the non‐treated group (P = 0.019). The tissue Na+‐K+ ATPase activity was significantly decreased in the non‐treated group than in the levosimendan‐treated group (P = 0.027). Tissue myeloperoxidase (MPO) enzyme activity was significantly higher in the non‐treated group than in the levosimendan‐treated group (P = 0.004). Electron microscopic examination of the hearts showed cardiomyocytic degeneration at the myofibril, mitochondria and sarcoplasmic reticulum in both non‐treated and levosimendan‐treated groups. The severity of these findings was more extensive in the non‐treated group. Conclusions: Treatment with levosimendan provided better cardioprotection with cold cardioplegic arrest followed by global hypothermic ischaemia in isolated rat hearts.