Sezgin Yilmaz

The effect of different intraabdominal pressures on lipid peroxidation and protein oxidation status during laparoscopic cholecystectomy

Background: This prospective, randomized, and controlled study was designed to investigate the effects of different intraabdominal pressures (IAPs) on lipid peroxidation and protein oxidation status during laparoscopic cholecystectomy (LC). Methods: Twenty-four patients (12 men, 12 women) who underwent LC at either 10 or 15 mmHg of IAP were randomized into two groups. Repeated blood samples were collected to measure thiobarbituric acid reactive substances (TBARS) levels to assess lipid peroxidation and protein carbonyl content and protein sulfhydryl groups to assess protein oxidation status. Results: Serum protein carbonyls and TBARS levels were found to be increased immediately after desufflation in both study groups when compared to the preoperative levels. On the other hand, protein sulfhydryl levels were found to be decreased in both study groups. Although increases in protein carbonyls and TBARS levels were more prominent in patients who underwent LC at 15 mmHg of IAP, this difference was not statistically significant between both groups. Conclusions: The results suggest that both 15 and 10 mmHg of LAP could lead to an increased oxidative stress response during LC, but no difference was found between the groups.

Can preconditioning reduce laparoscopy-induced tissue injury?

Background: Pneumoperitoneum (P) created to facilitate laparoscopy (L) is associated with splanchnic perfusion, ischemia/reperfusion (I/R) injury, and oxidative stress. In this randomized controlled experimental study with blind outcome assessment, we evaluated the effect of preconditioning (PRE) on L-induced I/R injury. Methods: The subjects were 40 Sprague-Dawley male rats. P was created in all except controls, using carbondioxide (CO2) insufflation under a pressure of 15 mmHg. PRE consisted of 10 min of P, followed by 10 min of deflation (D). The rats were randomized to the following groups: Group P was subjected to 60 min of P. Group P/D was subjected to 60 min of P, followed by 45 min of D. Group PRE/P was subjected to PRE, followed by 60 min of P. Group PRE/P/D was subjected to PRE, followed by 60 min of P and 45 min of D. Group C (control) was subjected to a sham operation, without P. Its anesthesia time was equal to that for group PRE/P/D. At the end of the experiments, the rats were killed; blood, liver, and kidney samples were then obtained and coded. Plasma alanine aminotransferase (ALT) and malondialdehyde (MDA), as well as homogenized tissue MDA levels and glutathione (GSH) activities, were measured; tissue samples were assessed for histopathological evidence of injury; all assessments were done by investigators blinded to the study design. The results were decoded and analyzed statistically with the Kruskal-Wallis and Mann Whitney tests. A p < 0.05 was considered significant. Results: Plasma ALT as well as plasma, liver, and kidney MDA levels and liver and kidney injury scores were increased, whereas liver and kidney GSH values were decreased in groups P and P/D, as compared to group C. Rats subjected to PRE before P had plasma ALT, kidney MDA, and kidney and liver GSH levels comparable to controls; their kidney and liver injury scores were higher than controls but significantly lower than nonpreconditioned animals. PRE enabled decreased plasma, kidney, and liver MDA as well as increased kidney GSH if applied before P; its efficacy on oxidative stress was limited to providing decreased kidney MDA and increased kidney GSH if applied before P/D. However, PRE significantly attenuated kidney and liver injury after P as well as P/D. Conclusion: PRE consisting of 10 min of P followed by 10 min of D decreases the oxidative stress induced by sustained P in the plasma, liver, and kidney. PRE significantly limits liver and kidney injury after prolonged P and P/D. After further studies to define its ideal timing, PRE before L incorporating P may have clinical relevance, especially for elderly patients or those with impaired hepatic and/or renal function or perfusion.

Protective effect of erythropoietin on renal ischemia and reperfusion injury

Background:  Multiple protective effects of erythropoietin (EPO), such as antiapoptotic, antioxidant, angiogenic and neuroprotective effects, against ischemia have been demonstrated in cell culture and animal models. Genistein is also a potent tyrosine kinase inhibitor. The aims of the present study were to evaluate the effects of EPO on renal ischemia/reperfusion injury and to determine the role of the tyrosine kinase pathway on this process.

Preconditioning-like amelioration of erythropoietin against laparoscopy-induced oxidative injury

BackgroundLaparoscopic surgery has gained wide acceptance for almost every kind of surgical procedure, although it has produced significant oxidative injury to intraabdominal organs depending on the pressure level and the kind of the gas used. The literature describes several preventive measures for decreasing the postlaparoscopic oxidative injury such as low intraabdominal pressure, gasless laparoscopy, and laparoscopic preconditioning. Erythropoietin was shown previously to decrease ischemia–reperfusion injury to the liver. The current study evaluated the effect of erythropoietin against laparoscopy-induced oxidative injury, as compared with laparoscopic preconditioning.MethodsFor this study, 64 male Spraque–Dawley rats were randomly assigned to one of the following groups. The control group was subjected to a sham operation. The laparoscopy group was subjected to 60 min of pneumoperitoneum. The laparoscopic preconditioning plus laparoscopy group was subjected to 5 min of insufflation and 5 min of desufflation followed by 60 min of pneumoperitoneum. The erythropoietin plus laparoscopy group was subjected to a subcutaneous injection of erythropoietin as a single 1,000-U/kg dose followed by 60 min of pneumoperitoneum. After 45 min of desufflation subsequent to cessation of pneumoperitoneum, blood, liver, and kidney samples were obtained from half of the rats. The other half of the rats were observed for a reperfusion period of 24 h. Tissue and blood samples also were obtained after this period.ResultsLaparoscopy produced significant oxidative injury, as compared with the sham treatment. Laparoscopic preconditioning produced significant amelioration of the ischemic injury. Although erythropoietin administration during the prelaparoscopic period decreased the pneumoperitoneum-induced oxidative injury, the beneficial effect of laparoscopic preconditioning was more pronounced.ConclusionLaparoscopic preconditioning is more effective than the preischemic administration of erythropoietin in reducing laparoscopy-induced oxidative injury.

The protective effect of erythropoietin on ischaemia/reperfusion injury of liver

BACKGROUND Besides its haematopoietic effect, erythropoietin (EPO) has multiple protective effects, i.e. antiapoptotic, antioxidant and angiogenic properties. The neuroprotective effects of EPO against ischaemia have all been demonstrated in cell culture and animal models. The aim of the study was to evaluate the effect of erythropoietin on ischaemia-reperfusion injury (I/R injury) of the liver. METHODS Forty-eight adult male Sprague-Dawley rats weighing 250-300 g were divided into three groups: group I, hepatic ischaemia-reperfusion (Hepatic I/R); group II, hepatic ischaemia-reperfusion + EPO (Hepatic I/R+ EPO); group III, sham. Hepatic ischaemia was created by placing a microvascular clamp on the hepatic pedicle for 45 minutes. EPO was given to group II at a dose of 1000 U/kg 120 minutes before the onset of the ischaemia. Blood samples and liver tissues were obtained after 45 minutes of reperfusion from half of the rats in each group. The remaining rats were killed after a 24-hour observation period and blood and tissue samples were obtained. Blood alanine aminotransferase, tumour necrosis factor-alpha (TNF-alpha), interleukin-2 (IL-2) and liver tissue malondialdehyde (MDA) levels were determined. Liver tissue histopathology was also evaluated by light microscopy. RESULTS In rats with hepatic ischaemia, serum levels of ALT, TNF-alpha, IL-2 and liver tissue levels of MDA were reduced by the administration of erythropoietin and the histopathological score was also less severe. CONCLUSION This study demonstrates that pre-ischaemic administration of EPO has protective effects on hepatic I/R injury.

A Comparison of the Oxidative Stress Response and Antioxidant Capacity of Open and Laparoscopic Hernia Repairs

BACKGROUND Free radical-induced lipid peroxidation that is associated with a decrease in the antioxidant status of plasma occurs in many kinds of surgical procedures. In this study, we aimed to investigate markers of oxidative stress--malondialdehyde (as thiobarbituric acid reactive substances), protein carbonyls, and protein sulfhydryls--in patients undergoing Lichtenstein tension-free hernioplasty (LH) or laparoscopic preperitoneal hernia (LPPH) repair. METHODS Seventeen patients with unilateral inguinal hernia and no complications or recurrence were included in this study. Ten were randomized to undergo LH and seven to LPPH repair. Heparinized blood samples were taken to measure the levels of oxidative stress markers in the patients undergoing hernia repair. Levels of malondialdehyde, protein carbonyls, and protein sulfhydryls were measured preoperatively and at 6 and 24 hours postoperatively in all patients. RESULTS Both types of hernia repair caused a significant increase in the oxidative stress response and a decrease in antioxidant activity. Plasma levels of malondialdehyde and carbonyls (indicators of oxidant activity) were significantly higher in the LH than in the LPPH repair group (P<.05), and plasma sulfhydryl levels (indicators of antioxidant activity) were significantly lower in the LH than in the LPPH group (P<.05). In both groups, significant differences were also found between the preoperative levels and the postoperative levels 6 and 24 hours (P<.05). CONCLUSIONS These data demonstrate that both LH and LPPH repair cause a significant increase in markers of oxidative stress; however, the oxidative stress response associated with LH is greater than that associated with LPPH repair.

The effects of increased intraabdominal pressure on colonic anastomoses.

BackgroundThis experimental, randomized, controlled study was designed to investigate the effects of increased intraabdominal pressure (IAP) on colocolic anastomoses. To our knowledge, this is the first study to address this important issue.MethodsFor this study, 50 Wistar albino rats were randomized into five groups. The animals in all the groups underwent laparotomy and colocolic anastomosis. The rats in the control group were not subjected to increased IAP. Accordingly, IAP’s of 14, 20, 25, and 30 mmHg were established by carbon dioxide insufflation and maintained for 60 min in study groups 1, 2, 3 and 4, respectively. Colocolic anastomosis was realized after these periods of IAP in the study group. Half of the surviving rats in all the groups were sacrificed on postoperative days 7 and 14 to allow comparison between the control and study groups with respect to their mean body weights, mean anastomosis bursting pressures, and histopathologic characteristics of their anastomosis sites.ResultsThe mean body weights of all the groups were comparable at all times during the study. The anastomosis bursting pressures of the animals subjected to increased IAP were lower than that of the control group, with the differences reaching statistical relevance for the animals subjected to an IAP of 20 mmHg or higher on postoperative day 7 (p<0.0005 for study groups 2, 3, and 4 vs the control group). The anastomosis bursting pressure showed an inverse correlation with IAP. The adequacy of mucosal layer formation at the anastomosis line was lower and the degree of inflammation was higher in the groups exposed to an IAP of 20 mmHg or higher in the control group (p<0.05 for both comparison among study groups 2, 3, and 4 vs the control group).ConclusionsAn IAP increased to 20 mmHg and higher was found to result in impaired strength and wound healing in colocolic anastomoses, as reflected by the decreased bursting pressure and mucosal layer formation, and by the increased inflammation at the anastomosis sites of animals subjected to high IAP values.

Changes in tissue-oxidative stress markers in an experimental model of laparoscopic donor nephrectomy.

Background. Laparoscopic donor nephrectomy (LDN) is associated with prolonged warm ischemia, which could potentially increase oxidative stress in the graft. Because pneumoperitoneum (Pp) used to facilitate LDN impairs renal perfusion, it could augment the effects of warm ischemia. Our experimental, randomized, controlled study with blind outcome assessment is the first to address this possibility. Methods. Wistar-Albino rats were randomized to 4 groups. Controls were subjected to a sham operation; the remainder were subjected to Pp with or without warm ischemia of differing durations. The kidneys were removed at the end of each experiment. The concentrations of malondialdehyde (MDA), protein carbonyl, and sulfhydryl groups and the activities of superoxide dismutase (SOD) and catalase were measured in renal samples as markers of oxidative stress. Renal samples were also evaluated histopathologically using light microscopy. Results. Pp promoted oxidative stress in renal tissues, with an increase of MDA and protein carbonyls and a decrease in protein sulfhydryls and SOD activity. Warm ischemia exerted an additive effect on Pp-associated oxidative stress only when sustained for 10 minutes. These changes occurred in the absence of light-microscopic evidence of overt tissue damage. Conclusion. In an experimental model resembling LDN, Pp and 10 minutes of warm ischemia emerged as additive factors with respect to causing increased oxidative stress in the kidney. Because these effects imply subtle injury not only in the harvested kidneys of live donors but also in the kidneys the donors retain, avoiding Pp and warm ischemia above 5 minutes during LDN appears advisable.

Efficacy of thoracic epidural analgesia for laparoscopic cholecystectomy

IntroductionPostoperative pain is a commonly observed phenomenon after laparoscopic procedures. The use of new low-solubility inhalation anaesthetics leads to faster induction and recovery, but the effect of analgesics on pain when used with them is not sufficiently known. Optimally, analgesic therapy should be started in sufficient time as to be effective at the point of emergence from anaesthesia. We compared the effectiveness of intravenous and epidural analgesia in patients undergoing general anaesthesia with sevoflurane for laparoscopic cholecystectomy in the early postoperative period.MethodsThirty adult patients with American Society of Anesthesiologists (ASA) physical status I–II, scheduled for laparoscopic cholecystectomy, were enrolled in this study. The patients in the intravenous group (n=15) received general anaesthesia with sevoflurane and intravenous infusion of 1.5 μg/ml/kg/h fentanyl analgesia followed by postoperative intravenous infusion of 1.0 μg/ml/kg/h fentanyl, supplied by a programmed continuous analgesia pump. The patients in the epidural group (n=15) had combined epidural analgesia with 0.125% bupivacaine plus 50 μg fentanyl and general anaesthesia with sevoflurane, followed by continuous epidural infusion of 4 ml/h bupivacaine 0.125% plus 50 μg fentanyl. Visual analogue scores and the patients’ needs for analgesics and were recorded.

Giant Proliferating Trichilemmal Tumor of the Gluteal Region

Background Proliferating trichilemmal tumors are rare cutaneous neoplasms that show features of typical pilar cysts but also show extensive epithelial proliferation, variable cytologic atypia, and mitotic activity. Proliferating trichilemmal tumors are benign lesions; however, there are numerous reports of malignant proliferating trichilemmal tumors. Objective We present a case of benign proliferating trichilemmal tumor of an 81-year-old woman that was located on the left superior gluteal region for 30 years. Methods A tumor measuring 9 × 7 cm was surgically excised with a 1 cm conservative margin of normal tissue. Results Based on the histopathologic findings of tumor, this case was diagnosed as proliferating trichilemmal tumor. The patients condition was successfully treated with total excision. Conclusions Our case is an unusual presentation of proliferating trichilemmal tumor. Physicians should be aware of this entity while differentiating cutaneous tumor located on the gluteal region.