Demir Kursat Yildiz

The Impact of Subconjuctivally Injected EGF and VEGF Inhibitors on Experimental Corneal Neovascularization in Rat Model

Aim and scope: To investigate the inhibitory effect of subconjunctival application of VEGF antibodies bevacizumab, ranibizumab, pegaptanib, and HER2 antibody trastuzumab on corneal neovascularization in a rat model of experimental corneal neovascularization. Material and method: Thirty male Wistar albino rats were included in the study. A chemical burn was induced in central cornea of one eye of the rats by a 75% silver nitrate and 25% potassium nitrate stick. Rats were randomly divided into five groups so that each group contained 6 subjects. Right after the chemical burn, 0.1 ml serum physiologic was injected subconjuctivally in control group (group 1). 1.25 mg/0.05 ml bevacizumab was injected in group 2; 1.2 mg/0.1 ml trastuzumab was injected in group 3; 0.5 mg/0.05 ml ranibizumab was injected in group-4; and 0.3 mg/0.1 ml pegaptanib was injected in group 5. On the 8th day of the experiment, rat corneas were photographed by digital photo-camera. Later, eyes of the sacrificed rats were enucleated and corneal speciements were histopathologically analyzed. The percentages of neovascularization on corneal photographs were examined with digital image analysis. Results: The percentage of corneal neovascularization in all treatment groups was found to be significantly lower than the control group (p < 0.05). Bevacizumab was found to be more effective than all other agents (p < 0.05). While the degree of inflammation and vascularization in bevacizumab and trastuzumab groups were significantly lower than the control group (p < 0.05), the difference was not significant in ranibizumab and pegaptanib groups (p > 0.05). In all treatment groups, fibroblast intensity was significantly lower than the control group. In terms of corneal thickness, no significant difference was observed between treatment and control groups (p > 0.05). Conclusion: Bevacizumab, ranibizumab, pegaptanib, and trastuzumab were found effective for the inhibition of corneal NV. In our study we detected that the most effective agent was bevacizumab.

The effect of subconjunctival platelet-rich plasma on corneal epithelial wound healing.

Objective: Single-dose subconjunctival platelet-rich plasma (sPRP) injections with or without antibiotic treatment were investigated for their effect on corneal epithelial wound healing in a rabbit model. Materials and Methods: A total of 24 rabbits were used in this study. After collecting intracardiac blood samples from 16 rabbits, platelet-rich plasma was obtained by centrifugation. Animals were divided into 3 groups. A mechanical corneal epithelial defect of 7-mm diameter was created on the central cornea of the right eye of each animal. Group 1 (n = 8) received only sPRP, whereas group 2 (n = 8) received sPRP with topical antibiotic throughout the study. The third group (n = 8) served as the control group. Each animal was examined daily under biomicroscope for 10 days. Epithelial defect was measured in horizontal and vertical diameter with a 1/100 sensitive micrometer, and area of the defect was calculated. One animal was sacrificed in each group on the third and seventh day, and all remaining animals were sacrificed on the 10th day. Corneal histopathology was investigated for epithelial regeneration, presence of inflammation, and structural integrity of fibroblasts. All data were statistically analyzed for difference between the study groups. Results: Group 1 had a significantly smaller size in horizontal and vertical defect diameters on each day as compared with the control group. Healing of the epithelial defect in group 1 was found to be significantly different than that in the control group (P < 0.05). No significant difference was observed between group 2 and control group except for the first day. Group 1 had a significantly better healing process after the fourth day as compared with group 2. Histopathological investigations revealed a steady fibroblast migration, quicker epithelial regeneration, and less inflammation in group 1 as compared with the other 2 groups. Discussion and Conclusions: sPRP seems to improve corneal epithelial wound healing. However, antibiotic and sPRP combination may have a retarded healing effect as compared with platelet-rich plasma alone.

Effects of subconjunctivally injected bevacizumab, etanercept, and the combination of both drugs on experimental corneal neovascularization.

OBJECTIVE To compare the effect of subconjunctivally injected bevacizumab, etanercept and the combination of both drugs on experimental corneal neovascularization in rats. DESIGN Experimental study. PARTICIPANTS 28 male Wistar-Albino rats. METHODS Right corneas of rats were cauterized by silver nitrate sticks. Rats were divided randomly and equally into 4 groups so that each group contained 7 subjects. Immediately after the cauterization, 0.05 ml normal saline was injected subconjunctivally in group 1 (control group); 0.05 ml (1.25 mg) bevacizumab was injected subconjunctivally in group 2; 0.05 ml (1.25 mg) etanercept was injected subconjunctivally in group 3; 0.05 ml (1.25 mg) bevacizumab and 0.05 ml (1.25 mg) etanercept was injected subconjunctivally in group 4. The rats were euthanized on the 8th day, and digital photographs were obtained before the eyes were enucleated. The area of corneal neovascularization was calculated from digital photographs. Corneal sections were analyzed by histopathologically. RESULTS The burn stimulus score was +1 or higher in all eyes. The difference of the neovascularization score between groups was found to be statistically significant (p = 0.001). The area of corneal neovascularization was 79.8% in group 1, 43.2% in group 2, 54.5% in group 3, and 34.8% in group 4. In group 4, corneal neovascularization was inhibited more than in the other groups. Histologic examination showed that the treatment groups had less neovascularization, inflammation, and fibroblast activity than the control group (p< 0.05). CONCLUSIONS Our study has shown that etanercept does have some antiangiogenic and anti-inflammatory effects in treatment of corneal neovascularization. The combination of bevacizumab and etanercept may be a promising approach in the treatment of corneal neovascularization.

Riluzole- and Resveratrol-Induced Delay of Retinal Ganglion Cell Death in an Experimental Model of Glaucoma

Abstract Purpose: To evaluate the effects of the neuroprotective agents riluzole and resveratrol on the survival of retinal ganglion cells (RGCs) when administered alone or in combination. Materials and methods: Experimental glaucoma was induced by injecting hyaluronic acid into the anterior chamber of Wistar albino rats weekly for a six-week period. Intraocular pressure was measured before and immediately after glaucoma induction. The neuroprotective effects of daily intraperitoneal injections of riluzole (8 mg/kg) and resveratrol (10 mg/kg) were evaluated and compared. After the six-week period, dextran tetramethylrhodamine was applied into the optic nerve and the density of surviving RGCs was evaluated by counting the labeled RGCs in whole mount retinas for retrograde labeling of RGCs. Results: The mean numbers of RGCs were significantly preserved in all treatment groups compared to the vehicle-treated glaucoma group (G). The mean number of RGCs in mm2 were 1207 ± 56 in the control group (C), 404 ± 65 in G group, 965 ± 56 in riluzole-treated group in the early phase of glaucoma (E-Ri), 714 ± 25 in riluzole-treated group in the late phase of glaucoma (L-Ri), 735 ± 29 in resveratrol-treated group in the early phase of glaucoma (E-Re), 667 ± 20 in resveratrol-treated group in the late phase of glaucoma (L-Re), and 1071 ± 49 in riluzole and resveratrol combined-treated group in the early phase of glaucoma (E-RiRe group). Conclusions: When used either alone or in combination, both riluzole and resveratrol, two agents with different mechanisms of action in glaucoma, significantly delayed RGC loss in this study’s experimental glaucoma model.

Tectocerebellar Dysraphism With Vermian Encephalocele

Tectocerebellar dysraphism is a very rare malformation associated with encephalocele and tectal deformity. This article presents tectocerebellar dysraphism with a solely vermian content of encephalocele and tectal beaking defined by magnetic resonance imaging (MRI) in a 5-month-old girl who was successfully treated surgically and demonstrated excellent prognosis at the 4-year follow-up.

Preventive effect of intravesical ozone supplementation on n-methyl-n-nitrosourea-induced non-muscle invasive bladder cancer in male rats

Although non-muscle invasive bladder cancer (NMIBC) is widely seen in men, most laboratory studies of new intravesical therapies to prevent NMIBC have been conducted on female animals. In addition, ozone (O3) has been shown to be a beneficial agent as an intravesical application in the treatment of various disorders. In the current study, we evaluated the immunohistopathological and oxidative-antioxidative effects of intravesical O3 treatment on n-methyl-n-nitrosourea (MNU)-induced NMIBC. Male Wistar-Albino rats (n=51) were divided into four groups: sham (n=6), O3 only (n=15), MNU only (n=15), and MNU+O3 (n=15). The MNU-only and MNU+O3 groups received MNU, and the O3-only group received saline every other week for 10 weeks. The MNU-only group received 1 ml saline in place of O3 treatment, whereas the O3-only and MNU+O3 groups were treated with 1 ml 25 µg/ml O3 between the 7th and 12th weeks. Rat bladders were collected in the 15th week for immunohistopathology and oxidant-antioxidant quantitation. Oxidant-antioxidant parameters were determined by ELISA. Although all surviving rats in the MNU-only group had preneoplastic (4/11, 36.4%) or neoplastic changes (7/11, 63.6%), a completely normal urothelium was observed in 2 rats (2/12, 16.7%) in the MNU+O3-group (P=0.478). More high-grade lesions were observed in the MNU-only group (4/11, 36.4%) than in the MNU+O3 group (1/12, 8.3%) (P=0.120). All oxidant-antioxidant parameters significantly increased (P<0.05) in the O3-only group compared with the sham group. However, only antioxidant superoxide dismutase was remarkably higher (178.9%, P=0.060) in the MNU+O3 group compared with the MNU-only group. This is the first methodologically and pathologically well-described male rat orthotopic bladder carcinogenesis model with intravesical MNU and administration of O3 in NMIBC.

Endobronchial recurrence of non-Hodgkin's lymphoma mimicking foreign body aspiration.

A 2-year-old patient with a history of non-Hodgkins lymphoma (NHL) was presented to our hospital with the complaint of shortness of breath and wheezing. Posteroanterior chest radiograph revealed hyperlucency and hyperexpansion of the right hemithorax. We performed computed tomography (CT) because of a suspicion of foreign body aspiration. CT revealed right main bronchus occlusion by a hypodense lesion. Bronchoscopy revealed a mass lesion in the right main bronchus which was histopathologically diagnosed as NHL. Only a few cases of endobronchial recurrence of lymphoma have been reported in the current literature, but there is no reported case in a pediatric patient.

Radiological findings of atypical extraskeletal Ewing sarcoma.

A 15-year-old boy was admitted with the complaints of disseminated bone pain and epistaxis. He had bicytopenia and elevated LDH. Histopathological and immunohistochemical analysis of bone marrow as...

Intracranial primitive neuroectodermal tumor in a child previously treated for Ewing sarcoma

A case of surgically resected solitary parenchymal brain tumor in a 13-year-old girl, who was treated 18 months ago with chemotherapy and radiotherapy for cervical vertebral Ewing sarcoma is presented. The intracranial primitive neuroectodermal tumor was detected after admission for severe headache. No other metastasis or recurrences were encountered following 14 months after brain surgery. The authors discuss whether this parenchymal brain tumor was a metastasis or a second primary Ewing sarcoma/ primitive neuroectodermal tumor.