Muhamet Kivilcim

The University of Arizona, Tucson, Arizona, United States

Are you Muhamet Kivilcim?

Claim your profile

Publications (20)27.41 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: To determine the retinal toxicity of intravitreal ketorolac tris salt and flurbiprofen. Thirty-two New Zealand rabbits were injected intravitreally with 125, 250, or 500 microg or 1 mg of ketorolac tris salt or flurbiprofen in one eye and 8 fellow eyes were injected with 5% dextrose as a control. All animals underwent indirect ophthalmoscopy and slit-lamp biomicroscopy before injection and on days 1, 7, and 14 after the intravitreal injection. Electroretinography was performed on all animals before injection and on day 14 after the injection before the animals were killed. The enucleated eyes were prepared for histology. Clinical examination, electroretinography results, and histological evaluation demonstrated no signs of retinal toxicity for either drug at any dose. Intravitreal doses up to 1 mg of ketorolac tris salt and 1 mg of flurbiprofen did not cause retinal toxicity in the rabbit eye.
    Ophthalmic Surgery Lasers and Imaging 01/2009; 40(1):38-42. · 1.46 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To evaluate retinal toxicity of varying doses of rapamycin when injected intravitreally in rabbits. Rapamycin is a potent immunosuppressive agent with significant antitumor and antiangiogenic properties, clinically approved for prevention of organ transplant rejection. Twelve New Zealand albino rabbits were divided into four groups. Four different doses of rapamycin were prepared in 0.1 ml: 20 microg, 50 microg, 200 microg, and 1000 microg. Each concentration was injected in one eye of three rabbits, and 0.1 ml volume of sterile BSS was injected into the contralateral eye of the three rabbits. Slit-lamp and fundoscopic examinations were performed and the animals were observed for 2 weeks for signs of infection, inflammation, and toxicity. A baseline ERG was performed before drug treatment and at day 14, after which the rabbits were euthanized. Histology of the enucleated eyes was studied to look for retinal toxicity. ERG results showed some decrease in scotopic response; however this was not dose related. ERG results were normal at 20 microg. Histological results showed no retinal toxicity in all groups. Although ERG changes were identified at dosages between 50-1000 microg, the histology of all groups up to 1000 microg did not show any discernable abnormalities.
    Arquivos brasileiros de oftalmologia 01/2009; 72(1):18-22.
  • [Show abstract] [Hide abstract]
    ABSTRACT: To evaluate the ocular toxicity of escalating doses of intravitreous adalimumab (Humira) in the rabbit eye. Twelve New Zealand albino rabbits received unilateral intravitreous injections of 0.1 ml of adalimumab 0.25 mg (three eyes), 0.50 mg (three eyes), 1.0 mg (three eyes) or 0.1 ml balanced salt solution (BSS, three eyes). Slit-lamp biomicroscopy and fundoscopy were carried out at baseline, day 1, 7 and 14 following intravitreous injection, while electroretinography (ERG) was carried out at baseline and day 14. Animals were euthanized on day 14, and histopathological examination of the eyes was performed. Slit-lamp biomicroscopy and fundoscopy were normal in eyes having received BSS, 0.25 mg or 0.50 mg adalimumab; however, inflammation was present in two of three eyes having received 1.0 mg adalimumab. Similarly, comparison of scotopic and photopic ERG light at baseline and day 14 demonstrated no changes in eyes receiving BSS, 0.25 mg or 0.50 mg adalimumab, but two of three eyes having received 1.0 mg adalimumab showed a greater than 30% reduction in a and b wave. Finally, histopathology demonstrated no differences between eyes receiving BSS, 0.25 mg or 0.50 mg of adalimumab, but two of three eyes injected with 1.0 mg demonstrated inflammatory cell infiltration of the vitreous and anterior chamber, with one of these eyes demonstrating retinal necrosis. Escalating doses of intravitreous adalimumab in rabbit eyes caused no detectable functional or structural ocular toxicity up to a dose of 0.50 mg. Administration of 1.0 mg in 0.1 ml was associated with an inflammatory reaction and retinal necrosis.
    Albrecht von Graæes Archiv für Ophthalmologie 07/2008; 246(6):907-11. · 1.93 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To evaluate the effect of topically administered doxycycline in various doses; the combination of triamcinolone acetonide and low-molecular-weight heparin (LMWH); and the combination of triamcinolone acetonide and doxycycline on experimental corneal neovascularization in rats. This project is the combination of 2 separate studies. First, the chemical cauterization of corneas in 36 eyes of 36 Long Evans male rats was performed by using silver nitrate/potassium nitrate sticks. Topical instillation of doxycycline at 0.05% (pH = 3.3), 0.1% (pH = 3.1), 1% (pH = 2.3), 2% (pH = 2.1), 2% (pH neutralized to 7.4), and normal saline continued for 7 days. Second, the chemical cauterization of the corneas in 24 eyes of 24 rats was achieved by application of silver nitrate/potassium nitrate sticks. Topical instillation of triamcinolone acetonide (10 microg/mL) and either LMWH (10 mg/mL) or doxycycline (10 mg/mL) was compared with normal saline treatment of 7 days. For both studies, the percent area of the cornea covered by neovascularization and scar in each group was calculated separately by using computer software on digital photographs. All corneas were evaluated histopathologically in study and control groups. The mean percent area of corneal neovascularization determined in the eyes given doxycycline 0.05%, 0.1%, 1%, 2%, and 2% (pH neutralized) study groups and control groups was 69.8% +/- 18.0%, 64.5% +/- 14.0%, 56.4% +/- 20.8%, 54.8% +/- 6.0%, 36.2% +/- 4.3%, and 69.4% +/- 5.7%, respectively. The mean of percent area of neovascularization in the 2% doxycycline (pH neutralized) doxycycline group was significantly less than that of the control group and the <1% doxycycline concentrations (P < 0.05). The percent corneal neovascularization in the 2% (pH neutralized) doxycycline group was not significantly different from that of the 1% and 2% doxycycline groups (P < 0.05). There was no significant difference in percent area of corneal scar between control and study groups (P > 0.05). The mean percent area of corneal neovascularization in triamcinolone acetonide and LMWH, triamcinolone acetonide and doxycycline, and control groups was 2.35% +/- 4.42%, 9.42% +/- 6.8%, and 64.7% +/- 10.0%, respectively. The mean percent area of neovascularization in the triamcinolone acetonide plus LMWH or triamcinolone acetonide plus doxycycline groups was significantly different from that of the control group (P = 0.001 for both). There was no significant difference between study groups with regard to percent area of neovascularization or percent area of corneal scar between the control and study groups. Topically administered combinations of triamcinolone acetonide plus LMWH or triamcinolone acetonide plus doxycycline had effects that contributed to efficient suppression of corneal neovascularization; these drugs were ineffective at similar concentrations used alone. Topically administered 2% (pH neutralized) doxycycline has antiangiogenic effects, which contributed to significant suppression on corneal neovascularization. This drug may be therapeutically beneficial in treatment of corneal neovascularization in clinical trials.
    Cornea 05/2008; 27(4):446-53. · 1.75 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To evaluate the effect of topically administered ascorbic acid on experimentally induced corneal neovascularization in the rat model. Corneal chemical cauterization of 72 eyes in Long-Evans male rats was performed using silver nitrate/potassium nitrate sticks. Nine groups of eight eyes were used to evaluate eight concentrations of ascorbic acid with one group of eight eyes serving as a control. Topical instillation of 100 mg/ml non-pH-neutralized ascorbic acid was performed in one group while the remaining seven groups were evaluated using pH-neutralized ascorbic acid in concentrations of 100 mg/ml, 50 mg/ml, 10 mg/ml, 5 mg/ml, 1 mg/ml, 500 microg/ml, and 250 microg/ml. The percentage of corneal neovascularization and burn stimulus score was determined for all the eyes. The means of percent of corneal neovascularization in ascorbic acid 100 mg/ml (non-neutralized), 100 mg/ml, 50 mg/ml, 10 mg/ml, 5 mg/ml, 1 mg/ml, 500 microg/ml, 250 microg/ml, and control group were 17.50 +/- 12.80 (p = 0.001), 17.00 +/- 19.30 (p = 0.001), 15.25 +/- 13.26 (p = 0.001), 17.62 +/- 11.89 (p = 0.001), 28.87 +/- 23.08 (p = 0.001), 29.62 +/- 16.91 (p = 0.001), 60.12 +/- 8.50 (p = 0.04), 65.62 +/- 2.26 (p = 0.185), and 68.25 +/- 4.06, respectively (Tables 1 and 2). All animals had a burn score of 2+ or higher (Table 1). Ascorbic acid applied in a topical solution appears to inhibit corneal neovascularization in the rat model of inflammatory neovascularization in concentrations in a dose-dependent manner. The optimal dose-effect relation was in our model found in concentrations between 1 mg and 500 microg/ml. At concentrations below 500 microg/ml there was no statistically significant inhibition in the degree of corneal neovascularization compared to control.
    Albrecht von Graæes Archiv für Ophthalmologie 11/2007; 245(10):1461-7. · 1.93 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To evaluate the effect of topically administered bevacizumab (Avastin) on experimental corneal neovascularisation in rats. Silver nitrate sticks (75% silver nitrate, 25% potassium nitrate) were used to perform chemical cauterisation on the corneas of 16 eyes from 16 male Long Evans rats. For the following 7 days, the 10 eyes in the treatment group were instilled with bevacizumab 4 mg/ml drops twice daily, whereas the 6 eyes in the control group received placebo (normal saline drops twice daily). Digital photographs of the cornea were analysed to determine the area of cornea covered by neovascularisation as a percentage of the total corneal area. In the bevacizumab-treated eyes, neovascularisation covered, on average, 38.2% (15.5%) (mean (SD)) of the corneal surface compared with 63.5% (5.0%) in the control group (p<0.02, Mann-Whitney U test). Topically administered bevacizumab (Avastin) at a concentration of 4 mg/ml limits corneal neovascularisation following chemical injury in the male Long Evans rat model.
    British Journal of Ophthalmology 06/2007; 91(6):804-7. · 2.73 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To assess the retinal toxicity of varying concentrations of intravitreally administered doxycycline, a member of tetracycline family. Fourteen New Zealand albino rabbits, divided into 5 groups, were used for this study. The initial concentration of doxycycline (100 mg) was titrated using 5% dextrose solution to the following concentrations in a volume of 0.1 ml: 2000 microg, 1000 microg, 500 microg, 250 microg, 125 microg, and 62.5 microg. Each concentration was injected into 2 rabbit eyes. Two control eyes received 0.1 ml of 5% dextrose solution. All animals were examined before and after injection using indirect ophthalmoscopy and slit-lamp biomicroscopy. Electroretinography (ERG) was performed on all animals prior to the intravitreal injection and 2 weeks post-injection. The animals were re-examined at this time by indirect ophthalmoscopy and slit-lamp biomicroscopy and were then subjected to euthanasia. Their eyes were enucleated and examined using light microscopy. The doxycycline injected group exhibited significant decreases in ERG of the eyes injected with 2000 microg, 1000 microg, 500 microg, and 250 microg/0.1 ml. No significant changes in the ERG were observed following the injection of lesser concentration levels. There were no signs of retinal toxicity on slit-lamp examination, indirect ophthalmoscopy, or light microscopy in all the eyes injected with doxycycline concentrations of 125 microg or lower. Doxycycline injected intravitreally appeared safe at concentrations of 125 microg/0.1 ml or less in albino rabbits. Intravitreal doxycycline may be beneficial, and is an inexpensive alternative drug which could be used in the treatment of bacterial endophthalmitis particularly against resistant Staphylococcus aureus organisms.
    Archivos de la Sociedad Espanola de Oftalmologia 05/2007; 82(4):223-8.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Objective: To determine the threshold photodynamic therapy parameters, required for choroidal vessel closure, with the photosensitizer, Lambda 27, in Dutch belted rabbits, using fluorescein angiography and histopathology. Design: A pre-clinical experiment. Place and Duration of Study: Department of Ophthalmology at the Tulane University Health Sciences Center, between June 2001 - July 2002. Patients and Methods: Dutch belted rabbits were divided into two groups. The first group was injected intravenously with an aqueous solution of Lambda 27 at 1mg/kg. Saline was injected intravenously into the second group (controls). Approximately 5 minutes after injection of Lambda 27, a diode laser, mounted on Zeiss 30 SL-M slit lamp, emitting light at a wavelength of 719 nm was used to apply photodynamic therapy to the fundus. Lesions were placed on the choroid of the rabbits at a fixed spot size of 1.5 mm, using powers ranging from 50 to 120 mW, for a duration of 5 to 80 seconds. Choroidal vessel closure was documented by fluorescein angiography, the following day, and by light microscopy, after the animals were sacrificed. Results: Choroidal vessel closure was documented using fluorescein angiography for all of the lesions placed at fluence of 22.7 J/cm2 and above. Histopathology also confirmed this finding. No choroidal vessel closure was seen in the rabbits treated with fluences less than 22.7 J/cm2 or in the control group. Conclusion: This experiment establishes threshold parameters for choroidal vessel closure using the photosensitizer, Lambda 27.
    Journal of the College of Physicians and Surgeons--Pakistan: JCPSP 05/2007; 17(4):215-8. · 0.30 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this study was to evaluate the retinal toxicity of high-dose intravitreal etanercept, a U.S. Food and Drug Administration-approved anti-inflammatory drug, in the rabbit model. Twenty (20) New Zealand albino rabbits were divided into 5 groups (n=4); eyes in each group were intravitreally injected with one of the following doses of etanercept: 125 microg, 250 microg, 500 microg, 1 mg, or 2.5 mg. One (1) eye in each animal was used for the study dose; the fellow eye was injected with buffered sterile saline as a control. All animals were examined using indirect ophthalmoscopy and slit-lamp biomicroscopy before and after intravitreal injection and at days 1, 7, and 14. Electroretinography (ERG) was performed on all animals before intravitreal injection and 14 days after injection. The animals were euthanized on day 14. Histological preparations of the enucleated eyes were examined with light microscopy for retinal toxicity. Clinical examination, histological evaluation, and ERG results of all 5 groups demonstrated no signs of retinal toxicity. Intravitreal doses as high as 2.5 mg of etanercept did not cause retinal toxicity. Intravitreal doses of up to 2.5 mg of etanercept may provide a more potent, prolonged effect than the lower doses previously recommended.
    Journal of Ocular Pharmacology and Therapeutics 03/2007; 23(1):57-62. · 1.29 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Firstly, the aim of this study was to determine the maximally tolerated dose of intravitreally injected povidone-iodine (PVP-I). A second aim was to test the efficacy of PVP-I on rabbit eyes infected intravitreally with Staphylococcus epidermidis. Phase I of the study used 16 New Zealand albino rabbits, divided into 4 groups (n=4 each). Animals were anesthetized and intravitreally injected with 0.1 mL of 50, 100, 200, or 400 micrograms (microg) of PVP-I in 1 eye, and with saline in the other. The animals were examined at days 1, 7, and 14, using indirect ophthalmoscopy and slit-lamp biomicroscopy; electroretinography (ERG) was performed before treatment and prior to euthanization. Histological preparations were examined to determine retinal damage. Phase II of the study divided 20 New Zealand albino rabbits into 4 groups (n=5 each). Animals were anesthetized and injected with 0.1 mL of S. epidermidis containing 3030 colony forming units (CFU) in 1 eye and saline in the other. Seven (7) h later, animals were treated with 0.1 mL of 20, 50, and 100 microg of PVP-I, or no treatment. Bacterial concentrations from extracted vitreous were determined 2 days following infection. Results were analyzed for statistical significance, using the Student t test and analysis of variance, and histologic preparations assessed the presence of endophthalmitis. Phase I of the study observed no retinal damage at any of the concentrations studied, as noted by indirect ophthalmoscopy, slit-lamp biomicroscopy, ERG, and histologic exam. Phase II of the study showed no statistical difference in bacterial counts between treatment and control groups. All infected eyes went on to develop endophthalmitis, as observed by indirect ophthalmoscopy and histologic preparations. These results suggest that 400_g of PVP-I can be tolerated intravitreally in rabbit eyes with no noticeable damage over a 14-day period. Results further showed that 100 microg of intravitreally injected PVP-I has no statistically significant effect on rabbit eyes injected intravitreally with 3030 CFU of S. epidermidis.
    Journal of Ocular Pharmacology and Therapeutics 03/2007; 23(1):70-7. · 1.29 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Objective: To assess the retinal toxicity of varying concentrations of intravitreally administered doxycycline, a member of tetracycline family. Methods: Fourteen New Zealand albino rabbits, divided into 5 groups, were used for this study. The initial concentration of doxycycline (100 mg) was titrated using 5% dextrose solution to the following concentrations in a volume of 0.1 ml: 2000 µg, 1000 µg, 500 µg, 250 µg, 125 µg, and 62.5 µg. Each concentration was injected into 2 rabbit eyes. Two control eyes received 0.1 ml of 5% dextrose solution. All animals were examined before and after injection using indirect ophthalmoscopy and slit–lamp biomicroscopy. Electroretinography (ERG) was performed on all animals prior to the intravitreal injection and 2 weeks post-injection. The animals were re-examined at this time by indirect ophthalmoscopy and slit–lamp biomicroscopy and were then subjected to euthanasia. Their eyes were enucleated and examined using light microscopy. Results: The doxycycline injected group exhibited significant decreases in ERG of the eyes injected with 2000 µg, 1000 µg, 500 µg, and 250 µg/0.1 ml. No significant changes in the ERG were observed following the injection of lesser concentration levels. There were no signs of retinal toxicity on slit-lamp examination, indirect ophthalmoscopy, or light microscopy in all the eyes injected with doxycycline concentrations of 125 µg or lower. Conclusions: Doxycycline injected intravitreally appeared safe at concentrations of 125 µg/0.1 ml or less in albino rabbits. Intravitreal doxycycline may be beneficial, and is an inexpensive alternative drug which could be used in the treatment of bacterial endophthalmitis particularly against resistant Staphylococcus aureus organisms (Arch Soc Esp Oftalmol 2007; 82: 223-228).
    Archivos de la Sociedad Espanola de Oftalmologia 01/2007; 82(4).
  • [Show abstract] [Hide abstract]
    ABSTRACT: To evaluate the effect of topically administered agents doxycycline, triamcinolone, low molecular weight heparin (LMWH), and flurbiprofen on experimental corneal neovascularization in rats. Chemical cauterization of cornea was performed in 36 eyes of 36 rats by using silver nitrate/potassium nitrate sticks. Topical instillation of doxycycline, triamcinolone, LMWH, flurbiprofen, and normal saline solution was continued for 7 days. Percent areas of cornea covered by neovascularization and covered by scar in each group were calculated by use of computer software on digital photographs. Groups were compared for any significant (P < 0.05) differences among them. The means of percent area of corneal neovascularization in triamcinolone, doxycycline, flurbiprofen, LMWH, and control groups were 13.3%, 35.5%, 50.6%, 66.7%, and 74.9%, respectively. The triamcinolone and doxycycline groups were different from control group (P < 0.05). There was no significant difference in the percent area of neovascularization between the LMWH and flurbiprofen groups compared with the controls. Although the effects of LMWH and flurbiprofen were not significant, there seemed to be a trend, and the lack of significance may be related to small sample size. Because the mechanisms of action of these agents are not identical to each other, performing other studies using combinations of them seems to be reasonable. There were no significant differences in percent area of corneal scar among groups. Topical instillation of commercially available triamcinolone and doxycycline seems to diminish corneal neovascularization caused by chemical cauterization of cornea in rats.
    Cornea 09/2006; 25(7):801-5. · 1.75 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To evaluate the in vitro energy attenuation by transpupillary thermotherapy (TTT) using an 810-nm diode laser after the treatment of exudative age-related macular degeneration. In this experiment, an 810-nm diode laser was coupled to a slit lamp to deliver laser energy to a laser-power sensor adjusted in the track of the laser light. The spotlight was 0.5 mm in diameter; duration of exposure, 3 seconds. Citrated Pasteur pipettes were filled with blood diluted in saline in several concentrations and placed in the path of the laser light. The absorption of the light measured by the power sensor was tested for various delivered irradiances between 50.92 and 509.29 W/cm2. The differences were analyzed statistically. There were significant differences in laser blockage comparing various conditions for all power levels (P<0.05). Increasing the proportion of blood resulted in more laser blockage with all irradiances (P<0.05). Blood significantly blocks the transmission of the 810-nm diode TTT laser.
    Lasers in Surgery and Medicine 08/2006; 38(6):643-6. · 2.46 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To determine the efficacy of various combinations of flurbiprofen, low molecular weight heparin (LMWH), and doxycycline on the inhibition of corneal neovascularization in rats. Chemical cauterization of the cornea in 32 eyes of 32 rats was performed using silver nitrate/potassium nitrate sticks. The animals were divided into 4 groups. Topical instillation of 0.015% flurbiprofen with 5 mg/mL LMWH (group 1); flurbiprofen with 10 mg/mL doxycycline (group 2); doxycycline with LMWH (group 3), and saline (group 4; control) was performed twice a day for 7 days. Slit-lamp photography was used to determine the percent areas of cornea covered by neovascularization and also by scar in each group. The means were compared to find any significant (P < 0.05) difference between groups. The animals were euthanized and the eyes enucleated for histological evaluation. The mean of percent area of corneal neovascularization 5 in group 1 was 48.5 +/- 13.1; group 2, 6.6 +/- 5.5; group 3, 22.0 +/- 27.6 and group 4, 64.6 +/- 9. The means of percent area of neovascularization in groups 2 and 3 were significantly lower compared with control and group 1. There was no significant difference in the percent corneal neovascularization between groups 2 and 3 or between group 1 and the control group. Histological findings were consistent with slit-lamp evaluations. Topical instillation of combinations of doxycycline with either flurbiprofen or LMWH can effectively inhibit corneal neovascularization made by chemical cauterization of the cornea in rats.
    Cornea 07/2006; 25(5):582-5. · 1.75 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To determine the retinal toxicity of 5-fluorouracil, by means of electroretinography and histopathology, at different doses in vitrectomized rabbit eyes injected with silicone oil. A pre-clinical experimental study. The Louisiana State University Eye Center and the Department of Ophthalmology at the Tulane University Health Sciences Center, between June 1999 and May 2002. Thirty-two New Zealand albino rabbits were used for the study. One eye per animal was used. After vitrectomy, the eyes were injected with 1 ml of silicone oil and then randomly divided into 4 groups. Group 1 was intravitreally injected with 0.2 ml of normal saline; Group 2 was injected with 200 microg of 5-fluorouracil; Group 3 was injected with 400 microg of 5-fluorouracil and Group 4 was injected with 800 microg of 5-fluorouracil. Electroretinography (ERG) was performed before and 14 days after intravitreal injections. Retinal histological examinations were performed after the animals were euthanized at the end of the experiment to document any retinal toxicity. There was less than 15 % ERG decrease in the eyes injected with normal saline and 200 microg of 5-FU. Moderate postoperative ERG decrease (30-50%) was seen in the animals injected with 400 microg of 5-FU. Eyes injected with 800 microg of 5-FU Silicone oil showed severe postoperative ERG decrease (80-100%). Histological examinations of the enucleated eyes were consistent with ERG results. No retinal toxicity was observed in the eyes injected with saline and 200 microg of 5-FU. Moderate retinal damage was seen in the eyes injected with 400 microg of 5-FU. Severe retinal damage was seen in the eyes injected with 800 microg of 5-FU. The results of this study suggest that doses lower than 2.5 mg of 5-FU are required for injection into silicone oil-filled vitrectomized rabbit eyes.
    Journal of the College of Physicians and Surgeons--Pakistan: JCPSP 06/2006; 16(5):351-4. · 0.30 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To evaluate the retinal toxicity of varying doses of bevacizumab when injected intravitreally in rabbits. Bevacizumab has been approved by the US Food and Drug Administration for the treatment of metastatic colorectal cancer. Twelve New Zealand albino rabbits were used for this study and divided into four groups. Four concentrations of bevacizumab were prepared: 500 microg/0.1 mL, 1.0 mg/0.1 mL, 2.5 mg/0.1 mL, and 5.0 mg/0.2 mL. Each concentration was injected intravitreally in one eye of each of three rabbits; 0.1 mL volume of sterile balanced saline solution was injected into the contralateral eyes. Slit-lamp and funduscopic examinations were performed and the animals were observed for 2 weeks for signs of infection, inflammation, or toxicity. A baseline electroretinogram (ERG) was performed before the drug treatment and at day 14 before the animals were killed. The enucleated eyes were prepared for histologic evaluation of retinal toxicity. Histologic and ERG results in all groups showed no retinal toxicity. However, some inflammatory cells were found in the vitreous at the 5-mg dose. Intravitreal bevacizumab did not appear toxic to the retina in albino rabbits at a concentration of 2.5 mg. Intravitreally injected bevacizumab should be evaluated for efficacy in choroidal neovascularization and macular edema.
    Retina 04/2006; 26(3):257-61. · 2.83 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To determine the retinal toxicity of triamcinolone acetonide at different doses in vitrectomized, silicone-filled rabbit eyes. Vitrectomy with silicone oil placement was performed in 32 rabbit eyes. A dosage of 1 mg/0.025 mL, 2 mg/0.05 mL, or 4 mg/0.1 mL of triamcinolone acetonide was injected intravitreally in the study group eyes; the control group received 0.1 mL of sterile saline. Electroretinography and retinal histology were performed to evaluate toxicity. No retinal toxicity was seen in the groups given 1, 2, and 4 mg of triamcinolone acetonide or in the control group. ERG and histologic sections in all groups were normal. No drug was visible in the vitreous cavity at the end of the 140-day period (average) in eyes injected with 4 mg of triamcinolone acetonide. Up to 4 mg of triamcinolone acetonide can be safely injected in silicone-filled, vitrectomized eyes without any significant retinal toxicity.
    Ophthalmic surgery and lasers 01/2000; 31(6):474-8.
  • [Show abstract] [Hide abstract]
    ABSTRACT: To evaluate the toxicity of intravitreal drugs in an eye filled with silicone oil for prolonged internal retinal tamponade. Vitrectomy was performed in 21 rabbit eyes, and the vitreous was replaced with silicone oil. Different concentrations of various drugs (ceftazidime, vancomycin, and ganciclovir) were injected intravitreally. Silicone oil increased the toxicity of these drugs, which were injected in previously determined nontoxic doses, possibly because of a reduction of the preretinal space. Injecting one quarter of the known nontoxic dose failed to show any toxicity. Nontoxic concentrations of intravitreal drugs can cause toxicity in a silicone-filled eye.
    Retina 02/1999; 19(6):553-7. · 2.83 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Objective: To assess the retinal toxicity of varying concentrations of intravitreally administered doxycycline, a member of tetracycline family. Methods: Fourteen New Zealand albino rabbits, divided into 5 groups, were used for this study. The initial concentration of doxycycline (100 mg) was titrated using 5% dextrose solution to the following concentrations in a volume of 0.1 ml: 2000 µg, 1000 µg, 500 µg, 250 µg, 125 µg, and 62.5 µg. Each concentration was injected into 2 rabbit eyes. Two control eyes received 0.1 ml of 5% dextrose solu- tion. All animals were examined before and after injection using indirect ophthalmoscopy and slit-lamp biomicroscopy. Electroretinography (ERG) was performed on all animals prior to the intravitreal injection and 2 weeks post-injection. The animals were re-examined at this time by indi- rect ophthalmoscopy and slit-lamp biomicroscopy and were then subjected to euthanasia. Their eyes were enucleated and examined using light micros- copy. Results: The doxycycline injected group exhibited significant decreases in ERG of the eyes injected with 2000 µg, 1000 µg, 500 µg, and 250 µg/0.1 ml. No significant changes in the ERG were observed
  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: To evaluate the toxicity of intravitreal drugs in an eye filled with silicone oil for prolonged internal retinal tamponade. Methods: Vitrectomy was performed in 21 rabbit eyes, and the vitreous was replaced with silicone oil. Different concentrations of various drugs (ceftazidime, vancomycin, and ganciclovir) were injected intravitreally. Results: Silicone oil increased the toxicity of these drugs, which were injected in previously determined nontoxic doses, possibly because of a reduction of the preretinal space. Injecting one quarter of the known nontoxic dose failed to show any toxicity. Conclusions: Nontoxic concentrations of intravitreal drugs can cause toxicity in a silicone-filled eye. (C) The Ophthalmic Communications Society, Inc.
    Retina 19(6). · 2.83 Impact Factor

Publication Stats

480 Citations
27.41 Total Impact Points

Institutions

  • 2008–2009
    • The University of Arizona
      Tucson, Arizona, United States
    • Tulane University
      • Department of Ophthalmology
      New Orleans, LA, United States
  • 2006
    • Hospital Universitario Virgen del Rocío
      Hispalis, Andalusia, Spain
  • 2000–2006
    • Louisiana State University Health Sciences Center New Orleans
      • • Department of Ophthalmology
      • • Eye Center
      New Orleans, LA, United States