T Erbengi

Marmara University, İstanbul, Istanbul, Turkey

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Publications (21)31.65 Total impact

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    ABSTRACT: We investigated the effects of percutaneous gasserian glycerol injection in dogs and reviewed the histopathological changes. Experiments were performed in 16 adult healthy mongrel dogs. In group 1 (8 dogs) normal saline and in group 2 (8 dogs) pure glycerol was injected in the right trigeminal ganglion. After these procedures, dogs in each group were sacrificed after 24 h (3 dogs), 7 days (3 dogs), 21 days (2 dogs). The trigeminal ganglion and nerve of both sides were removed by using microsurgical techniques and examined by light and electron microscopy. Group 1: in all sections, nerve cells, myelinated and nonmyelinated fibers revealed normal patterns with slight fibrosis. Group 2: in all sections, myelinated fibers showed disintegration and swelling of the myelin sheath, rupture of axon continuity, destruction of basal lamina, deformation of the myelin-axon relationship by both light microscopy and electron microscopy. The sections examined by electron microscopy also showed axonolysis in nonmyelinated fibers. The changes after 7 and 21 days were less prominent than after 24 h. In the left sides, there are no pathological changes. Glycerol has a neurolytic effect on the dog's trigeminal ganglion. These effects were not specific and selective for myelinated and nonmyelinated nerve fibers.
    Stereotactic and Functional Neurosurgery 02/2002; 79(2):94-106. · 1.46 Impact Factor
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    ABSTRACT: Cerebral vasospasm after subarachnoid hemorrhage (SAH) has remained a major cause of morbidity and mortality in patients with SAH. Excitatory neurotransmitters are gathered in the extracellular space during ischemia due to cerebral vasospasm and initiate or stimulate a series of pathophysiological biochemical processes which consequently lead to neuronal death. Tizanidine (Sandoz compound DS 103-282, 5-chloro-4,2 (2-imidazolin-2-yl-amino)-2,1,3-benzothiazol hydrochloride) is a centrally-acting muscle relaxant and a selective alpha 2 adrenoreceptor agonist which shows its effect by stimulating presynaptic alpha 2 adrenoreceptors in central ASPergic and GLUergic system by inhibiting aspartic acid and glutamic acid release. In this study, the effect of Tizanidine on vasospasm was evaluated. We used a femoral artery vasospasm model in rats which has been described by Okada et al. 60 rats were examined in three groups. The first group was used as control group (Control) (n = 20), in the second group subarachnoid hemorrhage was performed (SAH) (n = 20), in the third group Tizanidine was administered in addition to SAH (SAH + Tizanidine administration) (n = 20). Animals in SAH + Tizanidine administration group received 0.3 mg/kg/day intraperitoneally for 7 days. Seven days after the experiment, after perfusion-fixation, 10 mm segments of both femoral arteries were removed and the femoral artery was prepared for light microscope examination, scanning and transmission electron microscopy and for morphometric analysis. There was a statistically significant difference between the electron, scanning and light microscopic observations and morphometric analysis of SAH + Tizanidine administration group and SAH group, and no statistically significant difference between SAH + Tizanidine administration group and control group. This study has disclosed that Tizanidine administration before the vasospasm reduces ultrastructural and morphometric vasospastic insult significantly. However, the clinical application of Tizanidine as a protective and therapeutic agent in cerebral vasospasm needs further studies including the employment of clinically more relevant SAH models.
    Acta Neurochirurgica 02/2000; 142(9):1047-54. · 1.55 Impact Factor
  • Acta Neurochirurgica 01/2000; · 1.55 Impact Factor
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    ABSTRACT: To conduct an investigation of fetal cortical tissue graft survival using transmission electron microscopy and analyzing neurotransmitters and amino acids and their function, with special reference to the effect of dexamethasone. Transplantation of fetal cortical brain tissue to 100 adult Wistar albino rats weighing 170 to 220 g was performed. The rats were divided into three groups. Only transplantation of fetal cortical brain tissue was performed in the first group (n=36). In the second group (n=48), dexamethasone was administered in addition to fetal cortical tissue transplantation. The third group (n=16) was used as the surgical control group. The rats were allowed to live for 6 weeks and were then decapitated. The grafts were examined by electron microscopy. Additionally, quantitative analyses of the neurotransmitters and amino acids of the grafts were conducted using high-pressure liquid chromatography. Electron microscopic observations revealed that the grafts were still surviving at the end of the 6th week in both groups. However, in the group that received dexamethasone, neurons and their organelles were better developed than in the group that did not receive dexamethasone. Concommitantly, results of quantitative analysis in the dexamethasone group revealed statistically extremely significant higher amino acid values for glutamic acid, aspartic acid, beta-alanine, and lysine and significantly higher values for gamma-aminobutyric acid, glutamine, glycine, and serine when compared to the nondexamethasone group. Dexamethasone is effective in increasing the survival and in developing the ultrastructural and functional outcome of transplanted neurons in fetal grafts.
    Neurosurgery 06/1998; 42(5):1126-33; discussion 1133-4. · 2.53 Impact Factor
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    ABSTRACT: The effects of a cholesterol-rich diet and linolenate-derived polyunsaturated fatty acids (Omega-3; EPA and HDA) supplementation on the aortic ultrastructure and serum lipid profiles (total cholesterol, HDL-cholesterol, and LDL-cholesterol) were investigated in rabbits. Three groups were established as follows: Group 1 (control) rabbits received regular diet (n=8), Group 2 received regular diet enriched with cholesterol for 12 months (n=14), and Group 3 received regular diet enriched with cholesterol for 4 months, then replaced by Max-EPA supplementation in the remaining 8 months (n=14). Crater-like openings on the endothelial cells and the presence of lipid vacuoles in cholesterol-fed rabbits (Group 2) suggest a very rapid uptake of circulating plasma lipids from the aortic lumen. In Group 3, the ultrastructure of the endothelial cells was almost normal and no lipid vacuoles were noted. Lipids stored in the subendothelial and adventitial regions of the vessel were noted. Biochemical findings were in accordance with the ultrastructural findings in Groups 2 and 3. It is possible that, in the cholesterol-fed, EPA, and HDA-replaced rabbits, endothelial cells may stop or reduce lipid uptake from the lumen and/or the rate of transport of lipid particles may increase. In other words, the behavior of the endothelial cells might be altered by the polyunsaturated fatty acids, as well as their circulating lipid-lowering action.
    International Journal of Angiology 01/1997; 6(4):222-226.
  • 10th European Congress of Neurosurgery, Berlin, Germany, Mayıs, 1995.; 05/1995
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    ABSTRACT: It has been shown that a long-acting angiotensin-converting enzyme inhibitor cilazapril prevents morphologic changes in arteries secondary to hypertension and endothelial damage, which are analogous to the changes in cerebral arteries following subarachnoid hemorrhage. In this study, the effect of cilazapril on chronic vasospasm was investigated on the rat femoral artery vasospasm model, and morphometric analyses were performed. Animals were divided into three groups. In group 1, femoral arteries were removed after cardiac perfusion. In groups 2 and 3, right femoral arteries were exposed to 0.1 mL autologous whole blood and wrapped with silastic cuff. Animals in group 3 received cilazapril (10 mg/kg) for 7 consecutive days. After the perfusion-fixation, femoral arteries were examined by light and transmission electron microscopy and processed for morphometric analysis. Vessels from animals in group 2 showed a significant luminal narrowing and morphologic changes throughout the vessel wall, while vessels from animals treated with cilazapril appeared nearly normal. These results suggest that cilazapril may be effective in the prevention of chronic vasospasm.
    Surgical Neurology 05/1994; 41(4):294-8. · 1.67 Impact Factor
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    ABSTRACT: Proliferative angiopathy represents the morphological basis of delayed cerebral vasospasm. The initial vasoconstriction and endothelial damage of the vasospastic arteries leads to an exaggerated response of the smooth muscle cells within the media leading to subintimal thickening and myonecrosis. Heparin reduces the exposure of the media to platelet derived growth factor, a mitogen from aggregating platelets responsible for the migration and proliferation of the myofibroblasts. Since systemic heparin in the setting of a subarachnoid haemorrhage would be unacceptable, we have tested the effect of heparin on proliferative angiopathy by injecting autologous non-heparinized blood into two groups of rats (N = 12 each) and then inject the heparin into the spinal fluid of one group after one hour. We were able to show histologically that intracisternal heparin injection after the subarachnoid haemorrhage has reduced the vascular wall changes to a great degree. Heparinization of the cerebrospinal fluid carried out in conjunction with early operation for aneurysms may be a promising approach to prevent the morbid complications of SAH in the clinical setting.
    Acta Neurochirurgica 02/1994; 127(1-2):112-7. · 1.55 Impact Factor
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    ABSTRACT: The reactions of periventricular tissue of the lateral ventricle to non-infected and infected (Staphylococcus Epidermidis) silicone shunt tubing were examined by light and transmission electron microscopy. It was shown that reactive changes occurred in periventricular tissue in response to the implant of sterile shunt tubing. On the other hand in infected implanted silicone shunt tubing, proliferation of inflammatory cells within the ventricle and periventricular tissue, loss of integrity of the ependyma, glial cell proliferation, and excessive extracellular oedema were demonstrated. Proliferation of ependymal cells combined with inflammatory responses may be a factor in the pathogenesis of infected shunt obstruction.
    Acta Neurochirurgica 08/1993; 122(3):266-270. · 1.55 Impact Factor
  • T Erbengi
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    ABSTRACT: Chlamydia trachomatis infections are an important problem in human reproduction and family planning. In this study, the significance of chlamydial infection in male infertility and artificial insemination has been investigated. Electron microscope observations on male ejaculates have revealed the presence of the elementary and reticulate body forms of C.trachomatis in spermatozoa. Furthermore, the entry of the elementary body into the human spermatozoon head has been demonstrated. After the passage of the infectious elementary body into the nucleus, all stages of reticulate body formation in the head of the spermatozoon were detected. According to ultrastructural findings, C.trachomatis not only adhered to but also penetrated into the tail structure. Thus two different functional and morphological forms of C.trachomatis can infect and be transmitted by spermatozoa and may cause infertility.
    Human Reproduction 04/1993; 8(3):416-21. · 4.67 Impact Factor
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    ABSTRACT: In this study, the efficacy of ampicillin/sulbactam combination in reactions of periventricular tissue of the lateral ventricle induced by the presence of infected (Staphylococcus epidermidis) silicone rubber shunt tubing was examined by using light and scanning electron microscopy. It was demonstrated that reactive changes to implants had occurred in periventricular tissue in the control group. In infected shunt tubing without given prophylactic antibiotic group, generalized meningitis and ventriculitis, loss of integrity of ependymal cells, numerous inflammatory cells, bacterial colonies, exuda and even pus were seen. It was also shown that rarely inflammatory reactions, minimal disintegration of ependymal cells, no bacterial colonies, and phagocytes were present in the group which was given prophylactic ampicillin/sulbactam combination per and postoperatively. We think that ampicillin/sulbactam combination is very effective in prevention and treatment of shunt infections.
    Journal of neurosurgical sciences 04/1993; 37(1):19-23. · 0.53 Impact Factor
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    ABSTRACT: Idiopathic giant cell granulomatous hypophysitis is a rare disorder of pituitary gland characterised by a chronic inflammatory process. It can also be an extremely rare cause of hyperprolactinaemia. In this paper, we present our experience with two cases of idiopathic giant cell granulomatous hypophysitis manifested by hyperprolactinaemia, and their neuroradiological evaluation including preoperative MRI studies in one of them, and discuss our findings in the light of the literature.
    Neurochirurgia 02/1993; 36(1):20-5.
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    ABSTRACT: In prolactinoma surgery, especially in macro-adenomas, it is not always possible to remove the tumour totally. Cell remnants may cause a regrowth and continue hypersecretion. In order to find out whether tumour remnants could be destroyed by local application of bromocriptine, a research model has been designed. First, prolactin secreting pituitary tumours, removed during surgery, were implanted bilaterally into the brain tissue of rats. In eight rats, the viability of tumour transplants was proven histopathologically and their prolactin secretion was shown immunocytochemically. In a second step, on eight rats, sterile bromocriptine solution was applied topically to the tumour transplants on one side. The other side served as control. Histopathological examination of these treated tissues revealed fibrosis. Immunocytochemical analysis showed no secretory activity. Ultrastructural investigations also revealed evidence of degeneration of the treated cells. The natural course of the transplanted tumour tissues of the other side, as a control group, was also observed during the same 55-day period.
    Acta Neurochirurgica 02/1993; 120(3-4):175-9. · 1.55 Impact Factor
  • Y Gedikoglu, A Colak, K Benli, T Erbengi
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    ABSTRACT: The reactions of periventricular tissue of the lateral ventricle to non-infected and infected (Staphylococcus Epidermidis) silicone shunt tubing were examined by light and transmission electron microscopy. It was shown that reactive changes occurred in periventricular tissue in response to the implant of sterile shunt tubing. On the other hand in infected implanted silicone shunt tubing, proliferation of inflammatory cells within the ventricle and periventricular tissue, loss of integrity of the ependyma, glial cell proliferation, and excessive extracellular oedema were demonstrated. Proliferation of ependymal cells combined with inflammatory responses may be a factor in the pathogenesis of infected shunt obstruction.
    Acta Neurochirurgica 02/1993; 122(3-4):266-70. · 1.55 Impact Factor
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    ABSTRACT: The effects of n-3 fatty-acid supplementation on serum lipids, platelet aggregation, and the development of atherosclerotic lesions were studied in the cholesterol-fed rabbit. Serum total cholesterol and LDL cholesterol values were significantly reduced in comparison with those of the nonsupplemented cholesterol-fed group (p less than 0.005, p less than 0.0025, respectively), though still higher than those of the control group (p less than 0.0025, p less than 0.0125 respectively). Platelet aggregation was reduced below that of the cholesterol-fed and the control levels (p less than 0.0005, p less than 0.0025, respectively). The endothelial injury encountered in cholesterol-fed rabbits was inhibited in the supplemented group. It is concluded that n-3 fatty acids suppress atherogenesis in this animal model by interfering with platelet aggregation and lipid metabolism.
    Angiology 05/1991; 42(4):323-30. · 2.37 Impact Factor
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    ABSTRACT: The cytoprotective effect of iloprost on the viability and survival of embryonic cortical brain tissue grafts was examined ultrastructurally under light and electron microscopy before and 4 weeks after transplantation surgery. It was shown that neural grafts stored in iloprost solution (50 ng/mL) for 3 hours were more or less in a normal cytoarchitecture compared with saline-preserved grafts. Moreover, it was demonstrated that 4 weeks after transplantation, graft tissues stored in iloprost solution for 3 hours before implantation maintained a successful survival. Thus, a higher cellular population with new vascularization areas and preservation of myelin formation were accepted as a desirable integration of the graft tissue into the host brain tissue. The mechanism of action of iloprost is discussed.
    Surgical Neurology 11/1990; 34(4):212-8. · 1.67 Impact Factor
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    ABSTRACT: Systemic administration of acute idiopathic demyelinating polyneuropathy (AIDP) immunoglobulins to mice for two weeks resulted in reduced sural nerve action potential amplitudes and reduced (rotarod) motor performance. Electron microscopic examination of the sciatic nerves of the AIDP-immunoglobulin-treated animals revealed loosening of myelin lamellae with widening of interperiod lines and multivesicular disruption of myelin. Vacuolar degeneration was detected in half of the nerves examined by light microscopy. Injection of AIDP-immunoglobulins for three days led to only minor changes, and mice receiving healthy human immunoglobulins showed no abnormalities. These data show that some features of AIDP can be transferred to mice by systemic administration of immunoglobulins and suggest that humoral factors have a pathogenic role in AIDP in addition to cellular factors.
    Neuroreport 11/1990; 1(2):145-8. · 1.40 Impact Factor
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    ABSTRACT: The cytoprotective effect of iloprost was studied on isolated embryonic cortical brain tissue grafts of rats, using light and transmission electronmicroscopy. The brain tissue pieces were stored either in saline or 50 ng/ml iloprost solution for 30 minutes, 3, 6, 24 hours at +4 degrees C. It was demonstrated that iloprost significantly protected the neuronal integration of the tissue pieces compared with saline preserved pieces. Tissues preserved in iloprost showed only minimal dissolution of the tissue with minimal extracellular edema only in the later stages of preservation. The mechanism of action of the cytoprotective effect of iloprost is discussed.
    Prostaglandins Leukotrienes and Essential Fatty Acids 04/1990; 39(3):203-6. · 2.73 Impact Factor
  • Klinische Wochenschrift 02/1990; 68 Suppl 22:98-9.
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    ABSTRACT: The pituitary tissue, when transplanted to extracerebral sites other than the normal anatomic position, fails to perform its secretory function properly. Several works on experimental intracerebral pituitary transplantation have shown that the transplanted tissue has been able to survive histologically. In this study, fetal pituitary tissue was implanted into the anterior hypothalamic area of the hypophysectomized rat by stereotactic methods. Electron-microscopic examination and hormonal blood levels demonstrated that ectopic pituitary tissue was able to survive to establish the correct anatomic relationship and thus perform secretory functions when transplanted intracerebrally.
    Surgical Neurology 12/1988; 30(5):342-9. · 1.67 Impact Factor

Publication Stats

71 Citations
31.65 Total Impact Points

Institutions

  • 1993–2000
    • Marmara University
      • School of Medicine
      İstanbul, Istanbul, Turkey
    • Balikesir State Hospital
      Hadrianutherae, Balıkesir, Turkey
    • Istanbul University
      • Department of Histology & Embryology
      İstanbul, Istanbul, Turkey