Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Cengiz Güven is active.

Publication


Featured researches published by Cengiz Güven.


Scandinavian Journal of Urology and Nephrology | 2006

Protective role of natural antioxidant supplementation on testicular tissue after testicular torsion and detorsion

Ali Unsal; Muzaffer Eroglu; Asli Avci; Ersin Cimentepe; Cengiz Güven; M. Derya Balbay; I. Durak

Objectives . To investigate the impact of garlic extract (GE), which is known for its antioxidant activity, on a testicular torsion/detorsion model in animals and to help understand how to prevent both ischemic and reperfusion injuries after testicular torsion and detorsion. Material and methods. Six groups of rats (n=7 in each group) were used. The animals in the control group (Group I) did not receive any treatment. The animals in the sham group (Group II) underwent scrotal incision and testicular fixation only. The animals in Groups III–VI underwent 720° of left testicular torsion for 2 h; subsequent detorsion was performed for 2 h in Groups IV and VI only. Animals in Groups V and VI were treated exactly the same as those in Groups III and IV, respectively except that they were pretreated with oral GE for 5 days at a dosage of 5 ml/kg. Both testicles in all rats were removed and tissue malondialdehyde (MDA) levels and enzymatic activities of xanthine oxidase (XO) were studied, in addition to a histological evaluation after hematoxylin–eosin staining. Results. Testicular MDA levels and XO activities were higher in Group III compared to Group II (p<0.05). Pretreatment with GE prevented these increases. Detorsion caused more damage and resulted in a further increase in MDA levels but MDA levels were not increased in animals pretreated with GE. Histologically, torsion caused some separation between germinative cells in the seminiferous tubules, which became much more prominent in Group IV and was attenuated by GE pretreatment. There were no significant changes in any of the above-mentioned enzymatic activities or histopathologic changes in the contralateral testicle in any of the groups. Conclusions. We believe that both testicular torsion and detorsion result in testicular tissue damage by means of lipid peroxidation, which is evident by an increase in the tissue levels of MDA. Dietary supplementation with GE seems to attenuate the generation of toxic free radicals, as evidenced indirectly by low tissue MDA levels.


Journal of Herbal Pharmacotherapy | 2002

Effects of Garlic Extract Supplementation on Blood Lipid and Antioxidant Parameters and Atherosclerotic Plaque Formation Process in Cholesterol-Fed Rabbits

Älker Durak; H. Serdar Öztürk; Ekmel Olcay; Cengiz Güven

Objective: Possible effects of garlic extract supplementation on blood oxidant/antioxidant status, blood lipid profile and coronary plaque formation process were investigated in cholesterol-fed rabbits. Methods: Thirty-one male rabbits of New Zealand strain were used. Twenty-two animals were given cholesterol for 4 months. Seven of them were sacrificed to investigate plaque formation and to measure blood parameters. Seven of the remaining 15 animals were fed on normal laboratory diet and others normal diet plus garlic extract for additional 3 months. Blood antioxidant and lipid parameters were measured and histological examination was made. Results: Total, HDL and LDL cholesterol levels were found to be significantly higher in the Cholesterol Group relative to controls. In the histological investigation, a dense atherosclerotic plaque formation was observed in the aortas of this group. In the Normal Diet Group, total, HDL and LDL cholesterol levels were higher relative to the control group. No significant differences were observed between plaque surface areas of the Cholesterol and Normal Diet Groups. In the Extract Group however, there were differences with regard to all the analysis parameters. Total, HDL and LDL cholesterol levels were found to be decreased in this group. There was significant reduction in the plaque surface area in the aortas of this group. Blood antioxidant potential (AOP) was higher than the other groups but, malondialdehyde (MDA) level and, value of susceptibility to oxidation (SO) were lower in the Extract Group relative to the other groups. There were however no significant differences between MDA and SO values of the Control and Extract Groups. Conclusions: Our results demonstrate that cholesterol supplementation leads to dense plaque formation in the aortas of the rabbits. Garlic extract supplementation ameliorates blood lipid profile and, Increases antioxidant potential. Extract treatment can significantly reduce plaque surface area in the aorta. Our results suggest that increased blood antioxidant potential due to extract supplementation might be one of the factors leading to this end.


International Journal of Toxicology | 2007

Histological and Ultrastructural Evidence for Protective Effects on Aluminium-Induced Kidney Damage by Intraperitoneal Administration of α-Tocopherol:

Recep Kutlubay; Emin Oğuzhan Oğuz; Cengiz Güven; Belgin Can; Zafer Sinik; Ömer Levent Tuncay

The nephrotoxic actions of aluminium (Al) arise from its accumulation in the kidneys, with the resultant degeneration of the renal tubular cells. It has been suggested that Al generates reactive oxygen species that cause the oxidative deterioration of cellular lipids, proteins, and DNA. To test this hypothesis, we have here investigated the potential for a protective role of α-tocopherol (vitamin E) during short-term exposure of rats to Al. Al was administered intraperitoneally either alone or in combination with vitamin E at a different point of abdomen, and the alterations in the kidney tissue were analyzed histologically. The results reveal that significant light microscopical and ultrastructural damage is caused by Al, whereas with the immediate coadministration of vitamin E, there is a protective effect against this damage to the kidney tissue. In Al-alone group, the glomeruli and proximal tubuli and the Bowman capsules had swellings, adherence, hemorrhage, increase in mesengial matrix, and marked interstitial tissue fibrosis, indicating severe damage. In the Al and vitamin E immediate coinjected group, renal tubule cells were almost of a normal appearance. A slight stenosis was seen in the capsular area in the Malpighi corpuscules. The tubular organization and the cytoplasmic basophilia were also much the same as in the control group, with the lumen clearly visible in most of the cortical tubuli. The results highlight the need to reduce exposure to Al, with particular attention being paid to the known sources of Al. At the same time, the maintenance of a diet that is rich in vitamin E should be beneficial in the alleviation of Al toxicity.


Urology | 1998

Testicular Effects of Vasectomy in Rats: An Ultrastructural and Immunohistochemical Study

Kaan Aydos; Tarkan Soygür; Bora Küpeli; Ali Unsal; Özden Tolunay; Esra Erdem; Cengiz Güven; Sadettin Küpeli

OBJECTIVES The correlation between infertility and morphofunctional alterations following vasal occlusion is not clearly understood. Although a correlation has been found between the expression of a high titer of antisperm antibodies and the status of infertility, the relationship between the immunoglobulin (Ig) depositions in the testis and ultrastructural alterations of the peritubular structures has not been clearly established. The objective of this study is to explain the etiopathogenesis of diffuse and focal testicular lesions caused by vasal obstruction. METHODS Unilateral vasectomy was performed on adult male rats. Ultrastructural changes of testicular tissues and immunostaining affinity of peritubular structures with anti-actin, anti-vimentin, anti-laminin, and anti-immunoglobulin G (anti-IgG) antibodies were analyzed. RESULTS In an ultrastructural study, vasectomized animals presented abundant collagen fibril accumulation in the peritubular area. In testis with intense IgG antibodies, staining revealed weak immunostaining of peritubular myoid cells with anti-actin antibodies, but intense immunostaining with anti-vimentin antibodies. The tubules of rats with no IgG deposition on peritubular structures revealed intense immunostaining with anti-actin antibodies but scant immunostaining with anti-vimentin antibodies. Anti-laminin deposits decreased severely in most of the tubules demonstrating intense IgG deposition. CONCLUSIONS Our findings suggest that spermatogenesis deteriorates more severely in testes with dense IgG deposition. The sclerosis of the lamina propria in cases with vasal occlusion is secondary to alterations in the peritubular myoid cells. With the progressive changes that occur in the peritubular myoid cells or differentiation of the peritubular myoid cells that acquire active cell characteristics, collagen accumulation adjacent to these cells increases markedly. The alterations of the peritubular myoid cells reported here may be caused by alterations in basement membrane structures.


Neonatology | 2000

Role of Nitric Oxide in Hypoxia-Induced Changes in Newborn Rats

İlknur Kılıç; B. Alper Kiliç; Cengiz Güven; Ediz Demirpençe; M. Arif Akşit

In order to investigate the role of nitric oxide (NO) in hypoxic tissue damage in newborns, we studied the effects of systemic administration of an inhibitor of NO synthase, NG-nitro-L-arginine (L-NNA), and the precursor for the synthesis of NO, L-arginine (L-ARG), on the biochemical and histological changes in brain, heart, lung, liver, kidney, intestine, and skeletal muscle tissues. Four groups of 1-day-old Wistar rat pups were used: control, hypoxic, L-ARG, and L-NNA groups. L-ARG 100 mg/kg or L-NNA 2 mg/kg was administered as a bolus intraperitoneally 1.5 h before hypoxia. Hypoxia increased lipid peroxidation in all tissues except muscle; this increase was prevented by L-NNA and L-ARG in brain, heart, lung, kidney, and liver tissues. L-NNA in intestine and L-ARG in muscle tissue increased lipid peroxidation. The tissue-associated myeloperoxidase activity was decreased in the liver by L-NNA and L-ARG. Histopathological changes in intestines were villous epithelial separation and hyperemia in hypoxic and L-NNA groups which were not observed in control and L-ARG groups. In lungs, pulmonary hemorrhage was observed only in the hypoxic group. These data suggest that NO acts both as a destructive and a protective agent in the pathogenesis of hypoxia-reoxygenation injuries.


Pediatric Hematology and Oncology | 1998

Effects of Intra-Articular Vitamin E and Corticosteroid Injection in Experimental Hemarthrosis in Rabbits

B. Alper Kiliç; İlknur Kılıç; Mehmet H. Koseoglu; Cengiz Güven; Fahir Demirkan; Kamer Kilinc

The effects of intra-articular injections of vitamin E and corticosteroid were investigated in skeletally mature New Zealand white rabbits in which experimental hemarthrosis was induced for 14 days. The rabbits were divided into three groups composed of eight rabbits each: the first group comprised of animals with hemarthrosis, the second group animals with hemarthrosis and intra-articular injections of 20 mg vitamin E, and the third group animals with hemarthrosis and intra-articular injections of 10 mg of triamcinolone acetonide (TCA). Proteoglycan levels in the joint cartilage of the hemarthrosis group were found to be increased significantly compared with the controls (P < .01), whereas in the vitamin E-injected group they were significantly decreased (P < .05). In the TCA-injected group, proteoglycan levels were not found to be significantly different from those in the hemarthrosis group (P > .05). Histopathological evaluation showed that the cartilage structure in the joint of the control limbs was identical to that in the vitamin E- and TCA-injected limbs. In the hemarthrosis group, in comparison with the controls, the joint surface was roughened and fibrillated. In the superficial areas of the cartilage tissue, chondrocytes were decreased in number. These findings suggest that in this model, vitamin E and TCA may be helpful in preventing the joint cartilage changes seen in hemarthrosis.


Ophthalmologica | 1997

Histopathological and Ultrastructural Examination of the Rat Conjunctiva after Exposure to Tobacco Smoke

Avni Murat Avunduk; Mustafa Cihat Avunduk; Oya Evirgen; Serdar Yardimci; Hakki Tastan; Cengiz Güven; Kubilay Çetinkaya

Exposure to tobacco smoke can cause irritation of the conjunctiva. We conducted this study to identify the effect of tobacco on rat conjunctiva. Animals were divided into experimental and control groups and we exposed the experimental group to tobacco smoke. Control group rats inhaled only room air. Spectrophotometric analysis of the smoke-air mixture revealed that many toxic substances were present in this compound. We found very high levels of plasma thiocyanate after exposure to smoke in experimental group animals but no increase in the control group. So, this data indicates that these animals inhaled smoke effectively in our method. After 3 months conjunctivas were examined by light and electron microscopy. In the experimental group, conjunctivas were thinned, atrophied and microvillous projections and desmosomal connections were absent in comparison with the control conjunctivas. This pathologic change is very similar to conjunctival response to chronic irritants of any type.


Urology | 2010

Effects of Local and Sustained Release of FGF, IGF, and GH on Germ Cells in Unilateral Undescended Testis in Rats

Meltem Bingöl-Koloğlu; G. Berktug Bahadır; Rahsan Vargun; Hande İlkay; E. Umit Bagriacik; Sultan Yolbakan; Cengiz Güven; Tugba Endogan; Nesrin Hasirci; Hüseyin Dindar

OBJECTIVES To evaluate the effects of the local release of fibroblast growth factor (FGF), insulin-like growth factor (IGF), and growth hormone (GH) on a germ cell population of ipsilateral undescended and contralateral descended testes of rats with a surgically created unilateral abdominal testis for 12 weeks and after the application of growth factors after orchidopexy. METHODS Forty 4-week old male Wistar albino rats were divided into 5 groups as follows: group 1, sham; group 2, gelatin; group 3, FGF; group 4, IGF; and group 5, GH. In the sham group, the right testis was exposed and sutured with 5-0 silk sutures. In groups 2-5, a right intra-abdominal testis was surgically created. After 12 weeks, orchidopexy was performed, and 1 cm(2) gelatin films were sutured to the right testes, either unloaded (group 2), or containing 2.5 microg FGF (group 3), 5 microg IGF (group 4), or 5 microg GH (group 5). After 30 days, both testes were removed for histopathologic investigation and DNA flow cytometry. The mean seminiferous tubular diameters (MSTDs), mean testicular biopsy scores (MTBSs), and percentages of haploid (1n) cells were calculated. RESULTS Ipsilateral MSTD and MTBS significantly decreased in the gelatin and FGF groups compared with the sham, IGF, and GH groups. Contralateral MSTDs and MTBSs did not differ among groups. The haploid cell percentage significantly decreased in the ipsilateral and contralateral testes of the gelatin group compared with the sham, FGF, IGF, and GH groups. CONCLUSIONS Local release of IGF and GH resulted in the preservation of germ cell histology in the ipsilateral testes of rats with a surgically created unilateral undescended testis for 12 weeks and after orchidopexy. The administration of IGF, GH, and FGF increased the haploid germ cell population in both ipsilateral undescended and contralateral descended testes.


Operations Research Letters | 2007

Morphologic alteration induced by short-term smoke exposure in rats.

A. Cemal Ümit Işık; Serdar Yardimci; Cengiz Güven; Mustafa Cihat Avunduk; Şenol Civelek

Background: It is a well-established fact that cigarette smoking causes degenerative, inflammatory, and respiratory diseases in humans.Because many factors such as air pollution and harsh working conditions can easily be eliminated in animal studies, we conducted this study to identify the effect of tobacco on rat trachea. Methods: 24 male Wistar rats were divided randomly into an experimental and a control group. The experimental group of rats was exposed to cigarette smoke for 2 h each day over a duration of 60 consecutive days and the control group was treated in an identical fashion yet exposed only to room air. A morphometric study was performed on tracheal specimens taken from 22 rats (10 smoke-exposed rats and 12 control rats). Results: Our results show that many of the morphological changes of the tracheal epithelium were found in the experimental group and significant quantitative differences were observed between the two groups. Loss of cilia, basal cell hyperplasia, goblet cell hyperplasia and an increased number of subepithelial inflammatory cells were observed by light microscopic examination of the trachea of experimental rats. We found very high levels of plasma thiocyanate after exposure to smoke in the experimental group, but no increase in the control group. Conclusions: The oxidants contained tobacco which could play an important role in the development of these structural and functional abnormalities in the trachea after smoke exposure. In addition, smoking can recruit inflammatory cells to the trachea.


Pediatrics International | 2003

Effect of maternal NG‐nitro‐l‐arginine administration on fetal growth and hypoxia‐induced changes in newborn rats

İlknur Kılıç; Cengiz Güven; Kamer Kilinc

Background : Nitric oxide (NO) inhibition with NG‐nitro‐l‐arginine methyl ester (l‐NAME) in the last trimester of pregnancy caused intrauterine growth retardation and hind‐limb disruptions in rats. In the present study, the effect of maternal NO inhibition with NG‐nitro‐l‐arginine (l‐NNA) on hypoxic newborn rats was investigated.

Collaboration


Dive into the Cengiz Güven's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge