Relationship between DNA damage and total antioxidant capacity in patients with glioblastoma multiforme.

AIMS: To assess oxidative DNA damage and total antioxidant capacity (TAC) in glioblastoma multiforme (GBM) and to compare the results with normal brain tissues. MATERIALS AND METHODS: Oxidative DNA damage and TAC were evaluated in GBM tissues extracted from 26 patients and in normal brain tissues of 15 subjects who underwent autopsy within the first 4h of death. Oxidative DNA damage was assessed by measuring 8-hydroxy-2-deoxyguanosine (8-OH-dG) using the 8-OH-dG enzyme immunoassay kit, a quantitative assay for 8-OH-dG, and TAC was analysed using the ImAnOx colorimetric test system for the determination of antioxidative capacity. The results were compared between two groups and any correlation between 8-OH-dG and TAC was sought. RESULTS: The median level of TAC in GBM (121.5 nmol/g wet tissue) was remarkably lower than that in normal brain tissue (298 nmol/g wet tissue). The difference was statistically significant (P=0.00001). In contrast, oxidative DNA damage was significantly higher in patients with GBM (74.9 ng/g wet tissue) than in controls (34.71 ng/g wet tissue). Again, the difference was statistically significant (P=0.00001). We also found a negative correlation between oxidative DNA damage and TAC (P<0.001). CONCLUSIONS: These findings indicate that the degree of oxidative DNA damage is increased and TAC is decreased in GBM. Oxidative DNA damage is correlated with the levels of TAC.

Role of the antiangiogenetic drug paclitaxel on healing of intestinal anastomosis: an experimental study.

BACKGROUND: The aim of intraperitoneal administration of antineoplastic agents is the prevention of the implantation of tumoral cells after surgical intervention or the treatment of peritoneal carcinomatosis. The efficiency of intraperitoneal administration of paclitaxel, which is also an antiangiogenetic agent, has been investigated recently. The aim of this experimental study was to evaluate, taking into consideration its antiangiogenetic properties, the effects of intraperitoneal paclitaxel on healing of end to end colonic anastomosis. METHODS: 42 rats were allocated to 2 main groups (n = 21 for each group) to be evaluated on postperative day 3 (group A) and postoperative day 7 (group B). Each of the two main groups was divided into 3 subgroups (7 rats each). These subgroups were determined as control and two treatment groups administered paclitaxel in a dose of 2.5 mg/kg and 3.5 mg/kg intraperitoneally. Anastomosed segments of colon were harvested on postoperative day 3 or 7 and evaluated to determine bursting pressure of anastomoses, hydroxyproline levels and neovascularization with CD-31. RESULTS: In both groups, there were no significant differences between control and paclitaxel-treated groups with respect to bursting pressure. The level of hydroxyproline showed a significant decrease in all paclitaxel-treated groups compared with control groups (p = 0.001). Neovascularization was found to be decreased significantly on day 3 in the doses of paclitaxel 2.5 mg/kg (6.4 +/- 1.63) and 3.5 mg/kg (5.89 +/- 1.01) compared with control (8.02 +/- 0.88) (p = 0.029 and p = 0.005, respectively). There were no significant differences in neovascularization in either groups on postoperative day 7. CONCLUSION: We suggest that intraperitoneal administration of paclitaxel during surgical procedure decreases the hydroxyproline content and neovessel formation that are necessary for healing of intestinal anastomosis.

The influence of omentectomy on the inflammatory phase of anastomotic healing.

BACKGROUND/AIMS: Proper wound healing of the alimentary tract is essential for the prevention of the significant mortality and morbidity associated with complications. The effects of omentectomy on the inflammatory phase of anastomotic healing in rats were examined. METHODOLOGY: Sixty male Wistar-Albino rats that weighed about 200-220 g were used in this study. Animals were divided into three groups as colon anastomosis, colon anastomosis + partial omentectomy and colon anastomosis + total omentectomy. On the third postoperative day, all animals were sacrificed under anesthesia. Bursting pressure of anastomosis amounts and types of cells in the anastomosis, and nitric oxide, malondialdehyde, superoxide dismutase levels in the anastomosis and serum was examined. RESULTS: Bursting pressure values were 102.60 +/- 13.41 mm Hg, 105 +/- 10.80 mm Hg and 102.50 +/- 11.12 mm Hg in the colon anastomosis, colon anastomosis + partial omentectomy and colon anastomosis + total omentectomy groups, respectively (P > 0.05). A significant increase in macrophage count was found in the colon anastomosis + total omentectomy group when compared with the colon anastomosis group (P = 0.02). According to the comparisons with percentages, there was a significant difference in lymphocyte counts between colon anastomosis and colon anastomosis + total omentectomy groups (P = 0.04). The blood level of superoxide dismutase was higher in the colon anastomosis + total omentectomy group than the other two groups, and in the colon anastomosis + partial omentectomy group than the colon anastomoses group (P = 0.0001). There was a significant increase in the blood level of nitric oxide when comparing the colon anastomosis + total omentectomy group with colon anastomosis group (P = 0.02). The tissue level of malondialdehyde was higher in the colon anastomosis + total omentectomy group than the other two groups (P < 0.0001). CONCLUSIONS: Omentectomy may influence the outcome of the inflammatory phase of wound healing in rats. But systemic compensatory regulation of body can tolerate these detrimental effects and wound healing continues in its regular manner.

Is intestinal ischemia a risk of laparoscopy? An experimental study in rabbits.

BACKGROUND AND PURPOSE: In the literature, there are few reports documenting intra-abdominal organ necrosis following laparoscopic procedures. This experimental study was planned to investigate whether intestinal ischemia develops during laparoscopic procedures and if laparoscopy could cause intestinal necrosis. MATERIAL AND METHODS: Two experimental groups, each consisting of 10 adult New-Zealand rabbits, were used in this study. The first group comprised the study group which had pneumoperitoneum, the second group comprised the normal animals serving as the controls. A cervical tracheostomy was performed to achieve successful general anesthesia in both groups. In the study group, intraperitoneal CO2 insufflation was carried out and intraabdominal pressure (IAP) was adjusted so as not to exceed the arterial blood pressure. After 20 min high IAP period, the intraabdominal gas was aspirated. Five minutes later, samples of both small intestine and colon tissue were taken. In the control group, tissue samples were taken 25 min after anesthesia was achieved. Xanthine oxidase (XO) and malondialdehyde (MDA) levels were measured as indicators of intestinal ischemia and lipid peroxidation in the intestinal tissues. Statistical analysis was done to compare the XO and MDA levels of the small intestines and colons of both groups. RESULTS: The mean colonic XO levels were 1.323+/-1.17 and 0.217+/-0.27 (U/mg protein) in study and control groups, respectively. This difference was statistically significant (t = 2.60, p<0.05). The other comparisons with regard to XO and MDA levels were statistically not significant. CONCLUSION: Our results demonstrate that intraperitoneal CO2 insufflation in which intraabdominal pressure was adjusted to be lower than arterial blood pressure may affect oxygenization of the colon.

Nitric oxide (NO) metabolism in the cerebrospinal fluid of patients with severe head injury. Inflammation as a possible cause of elevated no metabolites.

BACKGROUND: This article investigates nitric oxide (NO) metabolism following severe head injury (SHI). We wished to clarify the alterations of NO metabolism end products that is associated with SHI, and to delineate the role of inflammation in this process. METHODS: In a prospective study, we simultaneously measured the concentrations of NO metabolites and interleukin-8 (IL-8) in the ventricular cerebrospinal fluid (CSF) of 11 patients who had suffered SHI. The CSF concentrations of nitrite (NO(-)(2)) and nitrate (NO(-)(3)) combined, and of IL-8 were measured during the following four time periods post-trauma: 6 to 10, 20 to 28, 40 to 56, and 64 to 74 hours. Levels were measured using the corresponding kits. RESULTS: Compared to the ventricular CSF control values, all of our SHI patients had significantly elevated CSF levels of NO(-)(2) plus NO(-)(3) (NO(-)(2) + NO(-)(3)) and IL-8 during all periods tested. CSF NO(-)(2) + NO(-)(3) and IL-8 concentrations reached their maximums simultaneously at 20 to 28 hours following trauma (Spearman's rank correlation = 0.609, p < 0.05), and NO(-)(2) + NO(-)(3) levels were significantly higher than those measured at 6 to 10, 40 to 56, and 64 to 74 hours. [Nitrite-nitrate concentrations: 6-10 hours: 19.22 +/- 6.75, 20-28 hours: 25 +/- 6.2 micromol/l, 40-56 hours: 19.82 +/- 4.47, and 64-74 hours: 19.72 +/- 4.61 micromol/l, (p < 0.05). IL-8 concentrations: 6-10 hours: 3,232 +/- 2,976.2, 20-28 hours: 3,458.45 +/- 3,048 pg/mL, 40-56 hours: 2,616.41 +/- 2,539.21, 64-74 hours: 1,388.88 +/- 1,216.7 pg/mL, (p < 0.001).]. This simultaneous surge in NO(-)(2) + NO(-)(3) and IL-8 in the initial 24 hours post-traumatic indicated that inflammation secondary to SHI increased the rate of NO metabolism, resulting in higher levels of metabolites in the CSF. CONCLUSION: In patients with SHI, CSF concentrations of the dominant metabolites of NO are elevated in the first 3 days after trauma. A similar concurrent spike in the CSF level of IL-8, a marker of acute inflammatory response, can also be demonstrated. These data indicate that the predominant cause of the higher CSF NO(-)(2) + NO(-)(3) concentrations observed in SHI is most likely inflammation.

Lipid peroxidation and antioxidants in preeclampsia.

OBJECTIVE: To determine the changes in plasma levels of lipid peroxide, vitamin E and vitamin C in women with preeclampsia and to investigate their relationship with diastolic blood pressure. STUDY DESIGN: Cross sectional study consisting of 22 preeclamptic and 21 healthy pregnant women. Fasting venous blood samples were collected during the antepartum period and plasma levels of malondialdehyde, alpha-tocopherol and ascorbic acid were measured. RESULTS: In the preeclamptic group malondialdehyde, a lipid peroxidation product, was significantly increased, while vitamins E and C were significantly decreased compared to healthy pregnant women. A strong correlation was detected between malondialdehyde and antioxidant factors (vitamins E and C) with blood pressure. CONCLUSION: Our findings are consistent with previous studies suggesting that lipid peroxidation is an important factor in the pathogenesis of preeclampsia. In preeclampsia, antioxidant nutrients are excessively utilised to counteract the cellular changes mediated by free radicals.

The effect of duration of compression on lipid peroxidation after experimental spinal cord injury.

The present study was performed to evaluate the effect of duration of acute spinal cord compression on tissue lipid peroxidation in rats. A clip compression method (1) was used to produce acute spinal cord injury. Rats were divided into 3 groups, each consisting of 10. At 1 hour after trauma all rats were sacrificed, and MDA content of the injured spinal cord segment was measured. The tissue MDA contents were 3.922 mumolMDA/gww in group 1 (control), 10.192 mumol MDA/gww in group 2 (30 seconds compression), and 12.147 mumolMDA/gww in group 3 (60 seconds compression). These results demonstrate that the length of duration of compression significantly enhances lipid peroxidation. Our study supported the view that persisting compression may cause progression of secondary mechanisms which may irreversibly eliminate any potential for recovery.

The effect of epidural cooling on lipid peroxidation after experimental spinal cord injury.

STUDY DESIGN: The effect of epidural space perfusion with chilled saline solution (% 0.9 NaCl) on lipid peroxidation after experimental spinal cord injury in rats was evaluated. OBJECTIVES: The extent of lipid peroxidation is a useful parameter for evaluating the cellular disturbance caused by spinal cord trauma in experimental conditions. The protective effects of hypothermia against neurological injury resulting from trauma or ischemia both in experimental and clinical situations have been demonstrated. SETTING: Departments of Neurosurgery and Biochemistry, Cerrahpasa Medical School, Istanbul, Turkey. METHODS: Twenty-five female Wistar Albino rats were used. There were five rats in group I (sham-operated), seven rats in group II (trauma), and eight rats in group III (epidural cooling). The remaining five rats were used for the pilot study to determine the spinal cord and body temperature. A clip compression method was used to produce acute spinal cord injury. In group III, 30 min after the trauma the injured spinal cord was cooled by perfusion of the epidural space with chilled saline solution (% 0.9 NaCl) with a flow rate of 5 ml/min for 30 min. At 2 h after trauma, all rats other than the ones used in the pilot study, were sacrificed and the spinal cords were excised. The extent of lipid peroxidation in the spinal cord was assessed by measuring the tissue content of malonil dialdehyde (MDA). RESULTS: The tissue MDA contents were 1.58 micromol MDA/gram wet weight (gww) in group I (sham-operated), 2.58 micromol MDA/gww in group 2 (trauma), and 1.77 micromol/gww in group 3 (epidural cooling), the differences being statistically significant. CONCLUSION: The results indicated that epidural cooling of traumatized spinal cord is effective in preventing secondary damage due to the peroxidation of lipid membranes.

The role of oxygen free radicals in acute renal failure complicating obstructive jaundice: an experimental study.

Oxidant injury is considered to be an important mechanism in the pathophysiology of acute renal failure. It has been thought that decrease in extracellular and intracellular fluid and endotoxemia seen in obstructive jaundice may cause an increase in production of oxygen free radicals and impairment in antioxidant defense mechanism. This study is designed to investigate the possible role of oxidant injury in renal failure seen in jaundiced patients. In this study, 28 rats were divided into four groups: Control (C)(N = 7); Renal ischemia (RI)(N = 7); Obstructive jaundice+renal ischemia (OJ+RI)(N = 7); Obstructive jaundice (OJ)(N = 7). All groups were compared with each other according to renal failure findings and enzyme activities, such as Xanthine oxidase (XOD), Superoxide Dismutase (SOD) and Catalase in renal cortex and Glutathione Peroxidase (GSH-Px), in blood at 3rd day after ischemia and reperfusion. Renal failure findings monitored by blood urea and creatinine levels, seemed more evident in OJ+RI than RI group (p < 0.05). When compared with RI, in OJ+RI group, increase in XOD activity at 3rd day was statistically significant [0.259 +/- 0.01 U/g (tissue) and 0.362 +/- 0.03 U/g (tissue) respectively] (p < 0.05). SOD and GSH-Px activities of each ischemic group at 3rd day were decreased compared to non-ischemic groups. This fall was significant (p < 0.05). But there was no statistical difference between jaundiced and non-jaundiced groups. Alterations in catalase activities also had no statistical significance. These findings may suggest that the injury induced by oxygen free radicals at re-oxygenation of tissue after ischemia may also play a role in the pathogenesis of acute renal failure developed in obstructive jaundice.

Effect of nimodipine and N-acetylcysteine on lipid peroxidation after experimental spinal cord injury.

The effectiveness of nimodipine and N-acetylcysteine in experimental spinal cord injury was evaluated by measuring tissue lipid peroxidation levels of the damaged spinal cords 1 hour after the injury We used the clip compression method to produce acute spinal cord injury in 40 female Sprague-Dawley rats were used. The rats were divided into four groups of 10 each. Lipid peroxidation was assessed by measuring the tissue content of malonil dialdehyde (MDA). In group 3, nimodipine, and in group 4, N-acetylcysteine, was administered i.p. as a single dose immediately after the injury. The rats were sacrificed 1 hour after clip application. The tissue mean MDA content was 3,992 micromol MDA/gww in group 1 (sham operated), 10,192 micromol MDA/gww in group 2 (trauma), 10,449 micromol MDA/gww in group 3 (nimodipine treatment) and 9,009 micromol MDA/gww in group 4 (N-acetylcysteine treatment). These results demonstrated that a single dose of nimodipine and N-acetylcysteine had no effect on peroxidation of lipid membranes in the early period of experimental spinal cord injury.

Changes in the activity of antioxidant enzymes (SOD, GPX, CAT) after experimental spinal cord injury.

We determined time dependent changes in the levels of the antioxidant enzymes, superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) at 1, 4 and 24 hours after standardized reversible spinal cord injury in rats. In each segment (rostral, lesion, caudal) enzyme activities at 1, 4 and 24 hours were not significantly different. Without time limitation we have found that SOD and GPx activities were not significantly different (p > 0.05), but CAT activity was significantly high (p = 0.008) in the lesion segment than the rostral and caudal segment. According to our results we suggest that one of the main reason for tissue damage during such a spinal cord trauma model may be neither H2O2 nor H2O2 derived radicals.