Atac Baykal
Hacettepe University
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Atac Baykal.
Journal of Laparoendoscopic & Advanced Surgical Techniques | 2001
Tarik Zafer Nursal; Atac Baykal; Duzgun Iret; Omer Aran
Situs inversus is a rare anomaly characterized by transposition of organs to the opposite side of the body. In this group of patients, cholelithiasis is observed with a frequency similar to the normal population. Herein, we report a patient with situs inversus totalis who underwent a successful laparoscopic cholecystectomy. Diagnostic pitfalls and technical details of the operation are discussed in the context of the available literature.
World Journal of Surgery | 1997
Atac Baykal; Demirali Onat; Kemal Rasa; Nurten Renda; Iskender Sayek
Abstract The purpose of this study was to investigate the effects of polyglycolic acid (PGA), an absorbable (ABS) mesh, and polypropylene (PP), a nonabsorbable (NA) mesh, on intestinal adhesion formation. Altogether 72 mice were divided into a control group of 24, an ABS mesh group of 23, and an NA mesh group of 25. All three groups were divided into two subgroups for evaluation of adhesion severity at postoperative (po) days 5 and 90. Adhesion severity was measured with adhesion grading and tissue hydroxyproline (OHP) levels. Adhesion degree was minimal (1) in all subjects on day 5. Also there was no difference in tissue OHP levels between three groups on day 5 ( p > 0.05). Adhesion degree and tissue OHP levels as determinants of adhesion severity were higher in the PGA mesh group than the control group and the PP mesh group on day 90 (p < 0.001). There was no difference between the control group and the PP mesh groups (p > 0.05). Adhesion degree was higher on day 90 than on day 5 in the control group and the PGA mesh group (p < 0.05), whereas tissue OHP level was higher on day 90 than on day 5 in all three groups (p < 0.001). Also there was linear correlation between adhesion degree and tissue OHP levels (r= 0.86, p < 0.001). The study demonstrates that ABS PGA mesh has higher potential for adhesion formation than the NA PP mesh, probably related to the increased foreign body and inflammatory reactions during the absorption process of the mesh.
American Journal of Surgery | 1998
Yusuf B. Ozogul; Atac Baykal; Demirali Onat; Nurten Renda; Iskender Sayek
BACKGROUND Depression of fibrinolysis is known to be a major mechanism for postoperative adhesion formation. Because aprotinin inhibits fibrinolysis it may lead to an increase in adhesion formation whereas its anti-inflammatory effects may lead to a decrease in adhesion formation. Our aim is to clarify conflicting results in previous literature. METHODS Basal levels of intestinal hydroxyproline (OHP) content and local fibrinolytic activity (LFA) were determined using naive groups. In the experiment groups, adhesions were created by scraping and creating a transient ischemia of a segment of terminal ileum. Group I and II rats were injected subcutaneous (s.c.) normal saline (NS) for 3 days and single dose intraperitoneal (i.p.) NS, respectively. Group III and IV rats were injected s.c. aprotinin for 3 days and single dose i.p. aprotinin, respectively. Group V rats were injected intramuscular methylprednisolone (MP) for 3 days. LFA and OHP levels were determined on the second and fifth postoperative days. The severity of adhesion formation was graded on the fifth day. RESULTS Aprotinin decreased both the severity of adhesions and OHP levels whereas MP decreased only the severity of adhesions. There was an early depression of LFA at the second day in both NS and MP groups increasing to basal levels at the fifth day. OHP levels showed significant correlation with adhesion severity. CONCLUSION Results showed that aprotinin decreased intra-abdominal adhesion formation probably by preventing early depression of LFA.
European Journal of Surgery | 2000
Atac Baykal; Alper B. Iskit; Erhan Hamaloglu; M. Oguz Guc; Gulsen Hascelik; Iskender Sayek
OBJECTIVE To investigate the effect of various doses of melatonin on reduction in mesenteric blood flow (MBF) and increase in tumour necrosis factor alpha (TNFalpha) concentration caused by injection of lipopolysaccharide (LPS). DESIGN University Hospital, Turkey. SETTING Open experimental study. ANIMALS 59 Swiss albino mice. INTERVENTIONS Animals were injected with melatonin solvent or 1, 10, 100, or 500 mg/kg melatonin. Ten minutes later control animals were injected with saline, and the experimental group with LPS. MAIN OUTCOME MEASURES Mesenteric blood flow and serum TNFalpha concentration. RESULTS In control animals, 100 and 500 mg/kg melatonin reduced MBF. LPS reduced MBF in solvent, 1, and 10 mg/kg melatonin groups. The concentration of TNFalpha was considerably increased in the mice given LPS. Melatonin reduced this response significantly. CONCLUSION In high doses melatonin directly reduces MBF. It has no protective effect on the LPS-induced decrease in MBF. In lower doses it blocks, but at higher doses reduces, LPS-induced TNFalpha production.
World Journal of Surgery | 2000
Atac Baykal; Burak Kavuklu; Alper B. Iskit; M. Oguz Guc; Gulsen Hascelik; Iskender Sayek
The septic shock-induced decrease in mesenteric blood flow and release of proinflammatory cytokines are among the major pathophysiologic changes presumed to lead to multiple organ dysfunction syndrome (MODS). Increased nitric oxide (NO) levels are associated with both decreased mesenteric blood flow and positive modulation of proinflammatory cytokine release. In this study we aimed to determine the effect of the timing of the inhibition of nitric oxide synthase (NOS) on mesenteric blood flow and serum interleukin-10 (IL-10) concentrations during endotoxin shock. A nonspecific NOS inhibitor NG-nitro-l-arginine methyl ester (l-NAME), a specific NOS inhibitor aminoguanidine (AG), or placebo were injected 20 minutes before or 20 minutes after a lipopolysaccharide (LPS) or placebo challenge to Swiss-albino mice, as pretreatment or posttreatment, respectively. At 120 minutes after LPS or placebo injection the mesenteric blood flow was measured, and blood samples from the heart were obtained for IL-10 levels in both groups. Pretreatment and posttreatment with both NOS inhibitors prevented the LPS-induced decrease in mesenteric blood flow. Pretreatment was more effective for this purpose. Pretreatment accentuated the LPS-induced increase in serum IL-10 concentrations, whereas posttreatment had no significant effect. We conclude that the timing of NOS inhibition is important for attenuating some deleterious effects of endotoxin.
Journal of Breast Cancer | 2012
Aysegul Oz; Figen Başaran Demirkazık; Meltem Gulsun Akpinar; Isıl Soygur; Atac Baykal; Sevgen Onder; Aysegul Uner
Purpose We performed this study to detect preoperative axillary metastases with ultrasound (US)-guided fine needle aspiration biopsy (FNAB), to eliminate the need for time-consuming and costly sentinel lymph node (SLN) scintigraphy and biopsy steps in the treatment of breast cancer patients, and in that of with suspicious US findings, and to evaluate the accuracy of preoperative US-guided FNAB for patients with suspicious lymph node metastases on US. Methods Patients with a suspicious breast lump or histopathologically proven breast cancer underwent breast-axillary US. Increase in lymph node size, cortical thickening, non-hilar cortical flow, and hilar changes were evaluated with gray scale-color Doppler US. FNAB was performed if US results were suspicious for malignancy. Results Thirty-eight axillary lymph nodes (ALN) underwent FNAB. ALN dissection, SLN scintigraphy, and biopsy steps were bypassed in 23 axillas with positive ALN FNAB (60.5%). The sensitivity of ALN FNAB was 88.46%; specificity and positive predictive value were 100%; and negative predictive value was 66.6% (inadequate cytology included; 76.7%, 100%, 100%, 53.3%, respectively). Asymmetrical cortical thickening, non-hilar cortical flow, and increase in hypoechogenity were only detected in metastatic nodes. Cortical thickening, and lymph node and breast mass size was higher in the metastatic group. Conclusion By performing FNAB on suspicious lymph nodes, the routine, high-cost SLN scintigraphy and intraoperative gamma probe steps may be skipped, and axilla dissection can be performed directly. This leads to the elimination of the need for SLN investigation in more than half of the patients. The assessment of ALN metastases with preoperative US-guided FNAB is a cost-effective method with high specificity, that eliminates the need for costly and time-consuming SLN scintigraphy and biopsy steps, and helps in preoperative staging.
World Journal of Surgery | 2007
Burhan Kabay; Çetin Kocaefe; Atac Baykal; Hilmi Ozden; Cengiz Baycu; Z. Oner; Meral Özgüç; Iskender Sayek
IntroductionThe aim of this study was to determine the effect of immunoregulatory cytokine interleukin-10 (IL-10) gene therapy on multiple organ injury (MOI) induced by a cecal ligation and puncture (CLP) model of sepsis in mice.MethodsMale Balb/c mice subjected to CLP were treated with either an hIL-10-carrying vector or an empty control vector. We assessed the degree of lung, liver, and kidney tissue destruction biochemically by measuring myeloperoxidase (MPO) and malondialdehyde (MDA) activity. Histologic assessments were based on neutrophil infiltration in lung and liver tissue. IL-10 protein expression was examined immunohistochemically, and ultrastructural changes in the liver were studied by transmission electron microscopy. We analyzed the expression of tumor necrosis factor-α (TNFα) mRNA by reverse transcription polymerase chain reaction 3, 8, and 24 hours after CLP in all organs.ResultsOrgan damage was significantly reduced by hIL-10 gene transfer, which was associated at the tissue level with reduced MPO activity in the liver, lung, and kidney and decreased leukocyte sequestration and MDA formation in the lung. The liver MDA was not significantly higher in the hIL-10 gene therapy group than in the controls and seemed not to be affected by hIL-10 gene transfer. The reduced portal tract neutrophilic infiltration and preserved ultrastructure of the hepatocytes also showed that tissue function was not impaired. The lung and kidney TNFα mRNA expression was suppressed markedly in the hIL-10 gene therapy group, but liver TNFα mRNA expression varied over time.ConclusionsThese findings showed that IL-10 gene therapy significantly attenuated sepsis-induced MOI.
European Journal of Surgery | 2000
Atac Baykal; Kaya Yorganci; Cenk Sokmensuer; Erhan Hamaloglu; Nurten Renda; Iskender Sayek
OBJECTIVE To assess the adhesive potential and incidence of incisional hernia with three meshes. DESIGN Open experimental study. SETTING Surgical Research Laboratory, Turkey. ANIMALS 75 Wistar albino rats INTERVENTIONS Abdominal walls were excised, and defects closed primarily or with polyglactin 910, polypropylene, or dura mater. Adhesions were graded and hydroxyproline concentrations measured on days 14 and 180. On day 180, the incidence of incisional hernia, and the grades of inflammation and fibrosis were also recorded. RESULTS The polyglactin 910 group had a higher adhesion grading than the control and dura mater groups on day 14, whereas the polypropylene group had higher adhesion grading than controls. Both polypropylene and polyglactin 910 groups had significantly higher concentration of hydroxyproline than the control and dura mater groups. On day 180, the polypropylene group had a higher adhesion grading than the controls. There were no differences in hydroxyproline concentrations, incidence of hernias, or grading of fibrosis levels among the groups. CONCLUSION Polyglactin 910 induced more fibrotic adhesions in the early postoperative period whereas polypropylene did in both the early and late postoperative periods.
World Journal of Surgery | 2004
Mehmet Ozdogan; Atac Baykal; Omer Aran
Amebic colitis perforation is a rare clinical form of amebiasis characteristically associated with high morbidity and mortality. We here present our series of eight patients with amebic colitis perforation. These patients represent 5% of 150 patients hospitalized during the same period for chronic amebic colitis. Only 50% of our patients had a correct preoperative diagnosis, and signs of generalized peritonitis such as rebound tenderness or muscular rigidity were not as common as might have been expected. Our mortality rate was 50% despite aggressive surgical treatment. Every effort should be made to have an early diagnosis, which would lead to early treatment with antiamebic agents, earlier and more limited surgery, and improved survival of these patients.
Surgery | 1999
Atac Baykal; Volkan Kaynaroğlu; Gulsen Hascelik; Iskender Sayek; Yılmaz Sanaç
BACKGROUND The epinephrine tolerance state has been demonstrated to increase survival in endotoxic shock and was claimed to have cross-tolerance with endotoxin tolerance. With use of these data, we aimed to determine the effect of epinephrine and endotoxin tolerance on major cytokine levels in a lipopolysaccharide challenge in mice. METHODS Epinephrine tolerance was induced by beginning with a low dose and gradually increasing to a lethal dose. Endotoxin tolerance was induced by injecting saline solution for 4 days and lipopolysaccharide 1 mg/kg on the fifth day. After these procedures, saline solution or 20 mg/kg lipopolysaccharide was injected into animals. Peak serum levels of tumor necrosis factor-alpha (TNF-alpha), interleukin 1 beta, interleukin 6 (IL-6), interleukin 10 (IL-10), and interleukin 12 (IL-12) were assayed. RESULTS The lipopolysaccharide injection increased the levels of all the cytokines in the control and epinephrine-tolerant animals. TNF-alpha, IL-6, and IL-10 levels were lower in endotoxin-tolerant animals compared with controls. Epinephrine-tolerant animals had higher levels of TNF-alpha, IL-6, and IL-12 than the controls did. CONCLUSION Epinephrine tolerance primes for an exaggerated release of TNF-alpha, IL-6, and IL-12 in response to lipopolysaccharide challenge, suggesting anti-inflammatory and immunosuppressive effects by epinephrine. The anti-inflammatory effect was not mediated through increased IL-10 release. Endotoxin tolerance selectively modulated cytokine release.