Vakur Olgaç

The effect of selenium and/or vitamin E treatments on radiation-induced intestinal injury in rats.

Cytotoxic effects of ionizing radiation on gastrointestinal epithelium may be related to oxidative stress. In this study, we wanted to investigate the effects of selenium, vitamin E and selenium plus vitamin E pretreatments prior to whole abdominal irradiation on intestinal injury. Irradiation caused increased lipid peroxide and decreased GSH levels in the intestine. Intestinal superoxide dismutase and glutathione peroxidase activities were increased, but glutathione transferase activity decreased following irradiation. Selenium and/or vitamin E pretreatments ameliorated these disturbances in prooxidant-antioxidant balance. This amelioriation has been verified with histopathological findings. These results indicate that antioxidant pretreatments prior to irradiation may have some beneficial effects against irradiation-induced intestinal injury.

Oxidative and nitrosative stress and apoptosis in the liver of rats fed on high methionine diet: protective effect of taurine.

OBJECTIVE There are few reports about the direct toxic effects of hyperhomocysteinemia on the liver. We investigated oxidative and nitrosative stresses and apoptotic and necrotic changes in the liver of rats fed a high-methionine (HM) diet (2%, w/w) for 6 mo. We also investigated whether taurine, an antioxidant amino acid, is protective against an HM-diet-induced toxicity in the liver. METHODS Lipid peroxide levels, nitrotyrosine formation, and non-enzymatic and enzymatic antioxidants were determined in livers of rats fed an HM diet. In addition, apoptosis-related proteins, proapoptotic Bax and antiapoptotic B-cell lymphoma-2 expressions, apoptotic cell count, histopathologic appearance in the liver, and alanine transaminase and aspartate transaminase activities in the serum were investigated. RESULTS Plasma homocysteine levels and serum alanine transaminase and aspartate transaminase activities were increased after the HM diet. This diet resulted in increases in lipid peroxide and nitrotyrosine levels and decreases in non-enzymatic and enzymatic antioxidants in liver homogenates in rats. Bax expression increased, B-cell lymphoma-2 expression decreased, and apoptotic cell number increased in livers of rats fed an HM diet. Inflammatory reactions, microvesicular steatosis, and hepatocyte degeneration were observed in the liver after the HM diet. Taurine (1.5%, w/v, in drinking water) administration and the HM diet for 6 mo was found to decrease serum alanine transaminase and aspartate transaminase activities, hepatic lipid peroxide levels, and nitrotyrosine formation without any change in serum homocysteine levels. Decreases in Bax expression, increases in B-cell lymphoma-2 expression, decreases in apoptotic cell number, and amelioration of histopathologic findings were observed in livers of rats fed with the taurine plus HM diet. CONCLUSION Our results indicate that taurine has protective effects on hyperhomocysteinemia-induced toxicity by decreasing oxidative and nitrosative stresses, apoptosis, and necrosis in the liver.

Do Vitamin E and Selenium Have Beneficial Effects on Trinitrobenzenesulfonic Acid-Induced Experimental Colitis

The balance between oxidant and antioxidant systems may be important in the pathogenesis and/or maintenance of tissue injury in ulcerative colitis. This study was designed to evaluate the effects of vitamin E and selenium supplementations on tissue injury and oxidative stress in trinitrobenzenesulfonic acid-induced ulcerative colitis in rats. Trinitrobenzenesulfonic acid administration severely changed the normal architecture of the colon and significantly increased the levels of malondialdehyde, protein carbonyl, and xantine oxidase (P < 0.001) in the colon homogenates of these rats. Supplementation of selenium to the trinitrobenzenesulfonic acid-treated rats neither improved the histopathological findings nor decreased the levels of malondialdehyde and protein carbonyl. Vitamin E supplementation reduced the levels of malondialdehyde and protein carbonyl but did not improve the colonic lesions. Supplementation of vitamin E+selenium significantly reduced both the severity of colonic lesions and the levels of malondialdehyde and protein carbonyl. In conclusion, we suggest that antioxidants and specific micronutrients may have beneficial effects in the treatment of ulcerative colitis.

Clinical and histopathological investigation of odontomas: review of the literature and presentation of 160 cases.

PURPOSE The purpose of the present study was to evaluate the clinical and histopathologic aspects of different types of odontomas. MATERIALS AND METHODS One hundred sixty odontoma cases sent to the Institute of Oncology, Department of Tumor Pathology, Istanbul University from 1971 through 2010 were investigated. These tumors were compared by age of patient, gender of patient, localization, histopathologic type, clinical diagnosis, and clinical and microscopic features. RESULTS Odontomas were classified histopathologically as complex, compound, or mixed. Of all investigated cases, 99 were complex, 57 were compound, and 4 were mixed odontomas. The mean age at diagnosis was 27.9 years, and odontomas were diagnosed most frequently at 10 to 19 years of age. CONCLUSIONS From the perspective of community health, the presence of odontomas within the jaws is important because these constitute 21% to 67% of all odontogenic tumors. The present study showed 2 interesting findings that differed from previous studies. These are the lower incidence rate of odontomas within the category of odontogenic tumors and the higher incidence of complex odontomas over compound odontomas.

Effect of taurine on oxidative stress and apoptosis‐related protein expression in trinitrobenzene sulphonic acid‐induced colitis

Ulcerative colitis (UC) is a multi‐factorial inflammatory disease of the colon and rectum. The present study was undertaken to investigate the effect of taurine, an anti‐oxidant amino acid, on oxidative stress and the expression of apoptosis‐related proteins, pro‐apoptotic Bax and anti‐apoptotic B cell lymphoma‐2 (Bcl‐2) in colon tissue in rats with 2,4,6‐trinitrobenzene sulphonic acid (TNBS)‐induced colitis. Rats received taurine (1·5% w/v) in drinking water for 15 days before and 15 days after administration of TNBS solution. Then, colonic myeloperoxidase (MPO) activity, malondialdehyde (MDA) and glutathione (GSH) levels, and Bax and Bcl‐2 expression were measured. TNBS‐induced colitis caused significantly increased MPO activity and MDA levels and decreased GSH levels in colon tissue compared to controls. Increase in Bax expression and decrease in Bcl‐2 expression were detected in colon of rats with TNBS‐induced colitis. Taurine treatment was associated with amelioration in macroscopic and microscopic colitis scores, decreased colonic MPO activity and MDA levels and increased GSH levels in TNBS‐induced colitis. In addition, taurine reduced the expression of Bax and prevented the loss of Bcl‐2 proteins in colon tissue of rats with TNBS‐induced colitis. The results of this study show that taurine administration may exert beneficial effects in UC by decreasing inflammatory reactions, oxidative stress and apoptosis.

The Effect of Melatonin on TNBS-Induced Colitis

Ulcerative colitis is a multifactorial inflammatory disease of the colon and rectum with an unknown etiology. The present study was undertaken to investigate the effect of melatonin administration on oxidative damage and apoptosis in 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis. Rats were divided into four groups as follows: Group 1 (n=8)—TNBS colitis; Group 2 (n=8)—melatonin, 10 mg/kg/day ip, for 15 days in addition to TNBS; Group 3 (n=8)—melatonin alone, 10 mg/kg/day ip, for 15 days; and Group 4 (n=8)—isotonic saline solution, 1ml/rat ip, for 15 days (sham control group). Colonic myeloperoxidase (MPO) activities, malondialdehyde (MDA) levels, and glutathione (GSH) levels are indicators of oxidative damage, while caspase-3 activities reveal the degree of apoptosis of the colonic tissue. In all TNBS-treated rats, colonic MPO activity and MDA levels were found to be increased significantly compared to those in the sham group. Colonic MPO activity and MDA levels were significantly lower in the melatonin treatment group compared to TNBS-treated rats. GSH levels of colonic tissues were found to be significantly lower in TNBS-treated rats compared to the sham group. Treatment with melatonin significantly increased GSH levels compared to those in TNBS-treated rats. Caspas-3 activity of colonic tissues was found to be significantly higher in TNBS-treated rats compared to the sham group. Treatment with melatonin significantly decreased caspase-3 activity compared to that in TNBS-treated rats. These results imply a reduction in mucosal damage due to anti-inflammatory and anti-apoptotic effects of melatonin.

Intraosseous lipoma of the mandible: A case report and review of the literature

Intraosseous lipoma is a benign tumor of the bone. It is mostly seen in the metaphyses of the long bones and calcaneus. There are few documented cases of intraosseous lipomas in the jaw. Clinically, the lesion is usually silent and radiologically it appears as a radiolucent area rarely including some radio-opacities. Diagnosis is based on clinical, radiological and histopathological features. Surgical removal of the lesion is the recommended treatment. The authors report a rare case of an intraosseous mandibular lipoma in a 45-year-old female, and review previously documented cases in the English literature. The histopathological and radiological features of the lesion are emphasized.

Oral and maxillofacial considerations in Gardner's Syndrome.

Gardners Syndrome is a variant of familial adenomatosis polyposis (FAP) with a triad consisting of polyps of the colon, multiple osteomas and surface tumors of soft and hard tissue. The intestinal polyps have a %100 risk of undergoing malignant transformation, therefore early identification of this disease is very important. There are several symptoms of Gardners syndrome in the oral and maxillofacial surgery, which can be discovered during routine dental examination. We report a case of a 25-year old male patient with Gardners syndrome who has not any intestinal polyps but osteomas in the mandible and jaw deformalities.

The effect of heme oxygenase-1 induction by octreotide on radiation enteritis

Radiation enteritis occurs as a response to abdominal radiation, which can cause mucosal damage in the gastrointestinal mucosal epithelium. The small intestine is one of the most radiosensitive organs in the abdomen. The present study was undertaken to investigate the effect of octreotide (OCT) administration on heme oxygenase-1 (HO-1) expression of the radiation enteritis model. Rats received 50 mg/kg/day OCT for 4 days before irradiation and continued for 3 days after irradiation. Intestinal myeloperoxidase (MPO) activities, malondialdehyde (MDA) levels are indicators of oxidative damage while caspase-3 activities reveal apoptosis degree of the small intestine. At histological examination, the terminal ileum tissue was analyzed for morphological changes. Irradiation significantly increased the intestinal MPO and caspase-3 activities, MDA levels and HO-1 expression in comparison to sham control group. OCT treatment was associated with increased HO-1 expression and caspase-3 activity, decreased MPO activity and MDA levels. Histological examination revealed that the intestinal mucosal structure was preserved in the OCT treated group. OCT appears to have protective effects against radiation-induced intestinal damage. This protective effect is, in part, mediated by modification of the inflammatory response and the induction of HO-1 expression.

Effect of Probiotic Supplementation on Bacterial Translocation in Thermal Injury

PurposeTo examine the effects of probiotic supplementation and enteral solutions containing glutamine and arginine on bacterial translocation (BT) and intestinal villous atrophy in thermal injury.MethodsForty male Sprague-Dawley rats weighing 200–250 g were divided into four groups of ten. Group 1 served as control group without thermal injury and was fed standard chow. Thermal injury was inflicted as a 30% scald burn in the other three groups. Group 2 was fed standard chow and group 3 was fed standard chow supplemented with a probiotic (Acidophilus plus) containing Bifidobacterium bifidum, Lactobacillus acidophilus, and Lactobacillus bulgaricus (2 × 109 CFU/day) via an orogastric tube. Group 4 was fed only an enteral diet (Stresson multifiber) containing glutamine, arginine, and medium chain triglyceride, at 1 g/kg per day amino acid and 230 kcal/kg, for 7 days before thermal injury. All the animals were killed 24 h after thermal injury, and ileal segments were resected and examined histopathologically. To evaluate BT, samples from blood, mesenteric lymph nodes, and cecal content were cultured under aerobic and anaerobic conditions. Terminal ileum specimens were histologically examined to evaluate mucosal integrity.ResultsSignificantly less BT was seen in groups 3 and 4 than in group 2 (P < 0.001). No significant difference was found between groups 3 and 4. Histological evaluation showed significant reduction in villous atrophy in groups 3 and 4.ConclusionProbiotic supplementation seems to reduce bacterial translocation and decrease intestinal mucosal atrophy in rats with thermal injury, as do enteral solutions with arginine and glutamine.