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Biomedical subjects

I Durak

Publications and source records attributed to I Durak.

At least 19 recordsLinked to original sources
PubMed2005

Adenosine deaminase and 5'-nucleotidase activities in saliva from patients with oral and laryngeal cancer.

OBJECTIVE: The aim of this study was to evaluate saliva's activities of adenosine deaminase (ADA) and 5'-nucleotidase (5'-NT) enzymes and their utility as diagnostic and therapeutic markers in oral and laryngeal cancer. MATERIALS AND METHODS: Pre- and post-operative saliva's activities of ADA and 5'-NT enzymes were measured in patients with squamous cell oral (n = 10) and laryngeal cancer (n = 17) and compared with control saliva samples (n = 19). RESULTS: The ADA was found to be lower in saliva of the patients with oral cancer compared with the laryngeal cancer and controls. However, no significant differences were found between pre- and post-operative values for both enzymes in the patient groups. We also could not find statistically significant differences between saliva's activities of 5'-NT in patients and control subjects. CONCLUSIONS: Low activity of ADA observed in saliva of the patients with oral cancer has been suggested as a compensatory mechanism against rapid purine and DNA metabolism in cancer cells. The current study does not support the hypothesis that saliva's activities of these enzymes may be used as additional diagnostic and prognostic cancer markers.

5'-Nucleotidase↗
PubMed2005

A potential role for nitric oxide pathway in tuberculous pleural effusion.

SETTING: Tuberculous pleural effusion leads to an immune response involving mainly immune and mesothelial cells. Nitric oxide (NO) produced by these cells may have antimycobacterial effects against Mycobacterium tuberculosis. OBJECTIVE: To investigate the possible role of NO in connection with the arginase enzyme, which controls the synthesis of NO through arginine depletion. DESIGN: Pleural fluid samples from 20 patients with tuberculous pleural effusion were used for arginase activity and NO level determination. Results were compared with those from 12 lung cancer, 12 pneumonia and 12 congestive heart failure (CHF) patients. RESULTS: Pleural arginase activity in tuberculosis patients was found to be significantly decreased compared to lung cancer and pneumonia groups, while the NO level was higher in tuberculosis patients. All groups except the CHF group had significant correlations between NO level and white blood cell count. Arginase activity and red blood cell count correlated significantly in lung cancer and CHF groups. CONCLUSION: The arginine-NO pathway seems to be involved in the pathogenesis of tuberculous pleural effusion. Decreased arginase activity may cause arginine accumulation, which may then lead to increased NO synthesis by immune and mesothelial cells, reflecting a host defence mechanism.

Aged↗
PubMed2004

Effects of cholesterol supplementation on antioxidant enzyme activities in rat hepatic tissues: possible implications of hepatic paraoxonase in atherogenesis.

BACKGROUND AND AIM: The effects of cholesterol supplementation on antioxidant enzyme activities were investigated hepatic tissue taken from Sprague Dawley rats. METHODS AND REULTS: The study involved 14 male Sprague Dawley rats: seven fed a normal laboratory diet and seven a normal diet plus cholesterol (3.6 g/kg/day) for three months, during which blood samples were obtained to measure serum cholesterol levels. At the end of the 3-month period, the livers were surgically removed in order to measure antioxidant enzyme activities (superoxide dismutase, catalase, glutathione peroxidase and paraoxonase-1). At the end of the study period, serum total cholesterol and HDL-cholesterol levels were significantly higher in the cholesterol-fed group than the control group. There were no significant between-group differences in hepatic superoxide dismutase, catalase and glutathione peroxidase activities, but there was a significant decrease in hepatic paraoxonase-1 activity in the cholesterol-fed group. CONCLUSIONS: Cholesterol supplementation significantly decreases paraoxonase-1 activity in rat liver tissue without changing the activities of other antioxidant enzymes. These results suggest that cholesterol significantly suppresses hepatic paraoxonase-1 synthesis. It seems that the decreased paraoxinase-1 activity in the plasma HDL-fraction of atherosclerotic patients is associated with suppressed liver synthesis. A reduction in paraoxonase-1 activity may therefore lead to the more intensive exposure of LDL to oxidant attacks.

Animals↗
PubMed2002

Effects of garlic extract on oxidant/antioxidant status and atherosclerotic plaque formation in rabbit aorta.

BACKGROUND AND AIM: The results of a number of studies suggest that garlic (or garlic extracts) may have favourable effects against the development of atherosclerosis. The aim of this study was to investigate the effects of garlic extract supplementation on oxidant/antioxidant status and atherosclerotic plaque formation in rabbit aortic tissue. METHODS AND RESULTS: Twenty-two male New Zealand White rabbits were fed a cholesterol-supplemented diet (0.5 g/Kg/day) and nine control rabbits a regular diet for four months. At the end of this period, atherosclerotic plaque formation and antioxidant activity were measured in the aortic tissue of the controls and seven of the cholesterol-fed animals. Of the remaining 15 experimental animals, seven were fed normal laboratory diet and eight a normal diet plus garlic extract (1.5 ml/Kg/day) for a further three months before atherosclerotic plaque formation and antioxidant activity were measured in the aortic tissue of both groups. The cholesterol-fed animals showed a significantly impaired antioxidant system associated with increased plaque formation. However, garlic extract supplementation significantly improved antioxidant status and reduced the plaque surface area. CONCLUSIONS: In this experimental model, garlic extract dietary supplementation activated the antioxidant system and decreased peroxidation in aortic tissue. There was also a reduction in atherosclerotic plaque area. Although further studies are required to elucidate the mechanisms involved, the protective activity of garlic extract may be due to its antioxidant properties.

Animals↗
PubMed2001

The role of Tc-99m RBC scintigraphy in the differential diagnosis of orbital cavernous hemangioma.

The cavernous hemangioma is the most common benign orbital tumor in adults. Its presentation is during the forth to fifth decades with a slowly progressive unilateral proptosis. Intraconal cavernous hemangiomas may be difficult to differentiate from other intraconal lesions such as schwannomas, meningiomas and hemangiopericytomas. We report a case of orbital cavernous hemangioma diagnosed by Tc-99m RBC scintigraphy. Tc-99m RBC scintigraphy revealed a typical scintigraphic pattern in which there is intense focally increased uptake on the delayed image. We conclude that Tc-99m RBC scintigraphy can be a useful method in the differential diagnosis of orbital cavernous hemangioma as in hepatic hemangioma.

Diagnosis, Differential↗
PubMed2001

The role of technetium-99m-HMPAO-labeled WBC scintigraphy in the diagnosis of orbital cellulitis.

Bacterial orbital cellulitis is an infection of the soft tissues behind the orbital septum. Cellulitis is seen as a poorly defined area of increased CT density or T2 signal intensity within the fat. There is an amorphous enhancement following contrast infusion. Radiolabeled leukocytes or granulocytes are now established widely as a means of localizing various forms of inflammatory disease and infections. We report a case of orbital cellulitis detected with Tc-99m-HMPAO-labeled WBC scintigraphy and three-phase bone scintigraphy. Tc-99m-HMPAO-labeled WBC scintigraphy was superior to bone scintigraphy in delineating the extension and limits of the infectious process in the orbita. Tc-99m-HMPAO-labeled WBC scintigraphy is appropriate in the investigation of such infectious lesions, leading to early diagnosis and therapy to avoid severe complications.

Cefotaxime↗
PubMed2001

Blood oxidant/antioxidant status of atherosclerotic patients.

In the present study, it is aimed to investigate oxidant/antioxidant status of plasma and erythrocytes from atherosclerotic patients and to establish the possible role of oxidant stress in the formation and progression of atherosclerosis. Antioxidant potential (AOP) values and malondialdehyde (MDA) levels were studied in erythrocyte and plasma samples from 40 atherosclerotic patients and 38 healthy controls. A total of 13 subjects in each group were smokers. AOP was found unchanged in erythrocytes but lower in plasma samples (P<0.0005) from atherosclerotic patients as compared with those of the controls. MDA levels were however higher in erythrocyte hemolysate (P<0.025), erythrocyte membrane (P<0.0005) and blood plasma samples (P<0.0005) from atherosclerotic patients than those of the controls. Moreover, AOP was found to be lower in plasma samples of smoker patients than that of non-smoker patients (P<0.05). In the control group, erythrocyte MDA level was higher in smoker group than that of non-smoker group (P<0.05). Results reveal the presence of oxidant stress in the blood samples from patients with atherosclerosis. It seems antioxidant therapy might give beneficial results for atherosclerotic patients.

Adult↗
PubMed2001

Magnetic resonance imaging characteristics of posterior scleritis mimicking choroidal mass.

We present imaging findings in a case of posterior scleritis, which may mimic tumoral mass lesion resulting in unnecessary enucleation. Magnetic resonance imaging was remarkable for a subretinal mass hypointense on T2 and hyperintense on T1 weighted images. A peripheral rim of hypointensity was noteworthy, suggestive of sclerouveal thickening. There was an ill-defined area of increased T2 signal intensity adjacent to globe at the site of nodular lesion implying an inflammatory process. A linear contrast enhancement was seen within the bulbus oculi which may represent detached retina by exudation or displaced retina due to thickened sclera and choroidal layers. The CSF space around the optic nerve was enlarged.

Adult↗
PubMed2001

Early postoperative capsular block syndrome.

PURPOSE: To report the results of early postoperative capsular block syndrome (CBS) after phacoemulsification and intraocular lens (IOL) implantation. SETTING: Department of Ophthalmology, Dokuz Eylül University School of Medicine, Izmir, Turkey. METHODS: Thirteen eyes of 13 patients with CBS who had uneventful phacoemulsification were included in the study. Twelve patients had in-the-bag implantation of a foldable IOL, and 1 had implantation of a poly(methyl methacrylate) IOL in the ciliary sulcus. Continuous curvilinear capsulorhexis was performed in all eyes, and sodium hyaluronate 1.4% (Healon GV(R)) was used during all steps of surgery. The patients were closely followed without intervention during the first month after surgery. If resolution did not occur during follow-up, a neodymium:YAG (Nd:YAG) laser peripheral anterior capsulotomy was performed first, followed by posterior capsulotomy if the anterior capsulotomy was not successful. RESULTS: The CBS resolved without intervention in 2 eyes by 1 month postoperatively. A small Nd:YAG laser peripheral anterior capsulotomy was attempted in 10 cases after 1 month but could not be performed in 2 eyes because of inadequate pupil dilation. Peripheral anterior capsulotomy was successful in 5 of 8 eyes, with resolution of CBS in a few days. The Nd:YAG laser posterior capsulotomy was successful in 5 cases after the failure of the anterior capsulotomy. One patient chose to postpone treatment for 11 months, at which time posterior capsulotomy was performed successfully and the CBS resolved. CONCLUSIONS: Resolution of CBS occurred spontaneously in only a small percentage of cases during the first month after phacoemulsification with IOL implantation. Neodymium:YAG laser peripheral anterior capsulotomy and posterior capsulotomy were successful in treating CBS.

Aged↗
PubMed2001

The evaluation of chronic progressive external ophthalmoplegia with computerized tomography.

INTRODUCTION: Chronic progressive external ophthalmoplegia is characterised by limitation of ocular motility in all directions of gaze and ptosis. Innervational or myogenic factors were claimed to be responsible for this motility disorder. The aim of this study was to investigate the extraocular muscles in CPEO with computerized tomography in an attempt to distinguish extraocular muscle morphology caused by this disorder from that occurring in normal individuals. METHODS: Eighteen orbits from 9 patients diagnosed with CPEO were included in the study. Axial and coronal scans were obtained for CT evaluation of extraocular muscles and the dimensions of extraocular muscles were measured. The control group consisted of 40 orbits belonging to 20 individuals and, the results were compared with a student's t test. RESULTS: The thickness (the vertical dimension of vertical recti and the horizontal dimension of horizontal recti) of all rectus muscles was significantly decreased in comparison with the control group, whereas the width (the horizontal dimension of vertical recti and the vertical dimension of horizontal recti) was similar in both the diseased and normal orbits. In all the rectus muscles of the diseased orbits, the normal fusiform shape was lost and the muscles appeared as thin bands. DISCUSSION: The differentiation of CPEO from other myogenic and neurogenic disorders may present difficulty, and a cluster of criteria are required for a final diagnosis. CT has proven to be a valuable tool in assessing extraocular muscles [1, 2]. In this study, an extreme atrophy of all rectus muscles was demonstrated by means of CT. This diagnostic method may consequently contribute to a proper diagnosis of CPEO.

Adult↗
PubMed2001

Unilateral retinal vasculitis, branch retinal artery occlusion and subsequent retinal neovascularization in Crohn's disease.

PURPOSE: To report on a case of Crohn's disease and unilateral retinal vasculitis, branch retinal artery occlusion and subsequent retinal neovascularization. METHODS: We examined a 38-year-old woman with severe left visual loss and biopsy-proven Crohn's disease diagnosed four years prior to the ocular involvement. A Heidelberg scanning laser ophthalmoscope was used for fundus fluorescein angiography and indocyanine green angiography. Retinal neovascularization was detected during the follow-up. RESULTS: Successful regression of retinal neovascularization was achieved after argon green laser panretinal photocoagulation in addition to oral steroid and salazopyrine. CONCLUSION: Retinal vascular involvement is a rare ocular feature of Crohn's disease and may result in retinal neovascularization that may necessitate prompt laser photocoagulation.

Adult↗
PubMed2001

Effects of isoflurane on nitric oxide metabolism and oxidant status of guinea pig myocardium.

BACKGROUND: Volatile anesthetics (VAs) have been shown to enhance myocardial recovery during reperfusion, the mechanism of which has not been clarified yet. It has been supposed that this effect of VAs may appear through antioxidative mechanisms. METHODS: Thirty guinea pigs were used in the study. There were three groups with 10 animals in each: I - control, II - isoflurane+oxygen and III - oxygen. Isoflurane (2.0% v/v) and oxygen (100%) mixture was given to the animals via a face mask in the isoflurane+oxygen group at the rate of 21 per min for 30 min a day for three consecutive days. In the oxygen group, oxygen alone (100%) was given under the same conditions as in the isoflurane+oxygen group. At the end of the experiments, the animals were killed and their hearts were removed. In the heart tissues, nitric oxide synthase (NOS) activity, nitric oxide (NO) pool (NO*+NO2-) and malondialdehyde (MDA) levels were measured. RESULTS: NOS activity was found to be higher and the NO pool lower in the isoflurane+oxygen group compared with those of control and oxygen groups. In the oxygen group, MDA level was found to be higher compared to the other groups. There was, however, no significant difference between MDA levels of the control and isoflurane+oxygen groups. CONCLUSION: Our results suggest that isoflurane prevents peroxidation reactions in heart tissue, possibly by scavenging toxic oxygen radicals produced under hyperoxygenation conditions as occurs with general anesthesia.

Anesthetics, Inhalation↗
PubMed2001

Aspirin impairs antioxidant system and causes peroxidation in human erythrocytes and guinea pig myocardial tissue.

This study aims to investigate possible effects of aspirin treatment on cellular oxidant/antioxidant system. In the first part of the study, 15 guinea pigs were given aspirin at three different doses (2200, 440 and 10 mg/kg/day) for 30 days and five were fed on the same diet without aspirin. After a month, animals were killed and their hearts were removed for use in analyses. In the other part, after fasting blood samples were obtained from 11 volunteer subjects, they were given aspirin (approximately 10 mg/kg/day) for 30 days and second blood samples were obtained after 1 month. Five volunteer subjects also participated as placebo control. Oxidant/antioxidant parameters, namely superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), malondialdehyde (MDA), nonenzymatic superoxide scavenger activity (NSSA), susceptibility to oxidation (SO) and antioxidant potential (AOP) values, were assayed in the samples. Antioxidant system was found to be impaired in the heart tissue from guinea pigs and in the erythrocytes from volunteer subjects. AOP and NSSA values were lower and MDA higher after aspirin treatment in both heart tissues and erythrocytes. In guinea pig heart tissue, SO was lower, but GSH-Px and CAT were unchanged after aspirin treatment. In human erythrocytes, SO was unchanged, but GSH-Px and CAT activities were increased after aspirin treatment. Changes in guinea pig heart tissues from animals treated with higher aspirin doses were more drastic relative to those of human erythrocytes, but no meaningful differences were observed between analysis parameters of control and lower-dose (10 mg/kg/day) aspirin-treated animals. Our results suggest that high-dose aspirin exerts significant toxicity to guinea pig myocardium and normal dose aspirin may cause peroxidation in the human erythrocytes due to its oxidant potential. We suppose that antioxidant supplementation may be beneficial for the people using aspirin for longer periods in order to prevent peroxidation damages.

Adult↗
PubMed2001

Erythrocyte nitric oxide metabolism in patients with chronic renal failure.

AIMS: This study aims to investigate arginine-nitric oxide pathway in chronic renal failure (CRF) and to establish erythrocyte nitric oxide synthase (NOS) and arginase (ARG) activities in patients with CRF. MATERIALS AND METHODS: NOS and ARG activities were measured in erythrocytes from 30 patients with CRF and 12-control subjects. RESULTS: Erythrocyte NOS activity was found to be significantly lower and ARG activity higher in patients with CRF compared with controls. No differences were, however, found between patients with and without hemodialysis. A negative correlation (r = -0.7) was established between ARG and NOS activities in erythrocytes from patients. CONCLUSIONS: Results suggest that erythrocyte NO production is diminished in patients with CRF, possibly due to decreased NOS and increased ARG activities.

Arginine↗