Comparison of the Effects Between Bevacizumab and Mitomycin C on the Survival of Fibroblasts

PURPOSE: To compare the antiproliferative effects between bevacizumab, a monoclonal antibody against vascular endothelial growth factor (VEGF), and mitomycin C in human Tenon's capsule fibroblasts. METHODS: Primarily cultured human Tenon's capsule fibroblasts were exposed to 0, 25, 50, 100, and 200 microg/ml bevacizumab and mitomycin C, and incubated for 5 days. Cellular survival and production of nitric oxide were assessed by MTT assay and Griess assay, respectively. RESULTS: Bevacizumab showed antiproliferative effects only at high concentrations (200 microg/ml) and revealed much less effect on the cellular survival compared to mitomycin C. In addition, bevacizumab did not affect the production of nitric oxide. CONCLUSIONS: The antiproliferative effect of bevacizumab is much lower than mitomycin C in human Tenon's capsule fibroblasts.

Acute Comitant Esotropia in a Child With a Cerebellar Tumor

We report a case of acute comitant esotropia in a child with a cerebellar tumor. A 3-year-old boy was referred for management of a 9 month history of acute acquired comitant esotropia. On first presentation, the patient's angle of esodeviation was 50 prism-diopters (PD) at distance and near fixation without any lateral incomitance. The cycloplegic refraction revealed +0.75 diopters in both eyes. Very mild bilateral papilledema was found on the fundus examination, but the neurological examination did not reveal any other pathological findings. Brain MRI showed a 5 cm mass located in the midline of the cerebellum as well as hydrocephalus. The mass was completely excised and histological examination confirmed the diagnosis of pilocytic astrocytoma. Despite neurosurgery, the patient's strabismus remained unresolved. One year after neurosurgery, both medial rectus muscles were surgically recessed by 6 mm, resulting in esotropia of 8PD at distant and near fixation without restoration of bifoveal fusion at follow-up 2 years after the eye muscle surgery. Therefore, acute onset comitant esotropia in a child can be the first sign of a cerebellar tumor, even without any other neurological signs and symptoms.

Effect of Bevacizumab on Survival and Production of Nitric Oxide in Trabecular Meshwork Cells

PURPOSE: To investigate the effect of bevacizumab, a monoclonal antibody against vascular endothelial growth factor (VEGF), on the survival and production of nitric oxide (NO) in human trabecular meshwork cells (HTMC). METHODS: Primarily cultured HTMC were exposed to 0, 0.25, 1.0, and 2.5 mg/ml bevacizumab for 24 hours. Cellular survival and production of NO were assessed by MTT assay and Griess assay, respectively. RESULTS: Bevacizumab did not affect the cellular survival at low concentrations but decreased cellular survival significantly at high concentrations (>1.0 mg/ml) accompanied with increased NO production. CONCLUSIONS: High concentrations of bevacizumab may be toxic to HTMC.

Effect of Methylglyoxal on the Oxidative Stress in Trabecular Meshwork Cells

PURPOSE: To investigate the effect of methylglyoxal (MG), intermediate metabolite of advanced glycation end products(AGE), on the induction of oxidative stress in human trabecular meshwork cells (HTMC). METHODS: Primarily cultured HTMC were exposed to at concentrations of 0, 30, 100, and 300 micrometer of MG for 18 hours, with or without co-exposure to N-acetyl-cysteine. Cellular survival and apoptosis were assessed by MTT assay and flow cytometry using annexin-PI double staining. Production of nitric oxide (NO), superoxide, and reactive oxygen species (ROS) was assessed by Griess assay, cytochrome c assay, and dichlorofluorescein diacetate assay, respectively. RESULTS: MG did not affect cellular survival at concentrations under 100 micrometer, but induced apoptosis of HTMC at concentrations over 100 micrometer. MG decreased NO production, accompanied with increased superoxide production. In addition, MG increased ROS, which were abolished by N-acetylcysteine. CONCLUSIONS: MG induced oxidative stress by decreasing NO production, accompanied by increasing superoxide and ROS productions in HTMC. AGE could induce trabecular meshwork dysfunction.

Effect of Hydrogen Peroxide-induced Oxidative Stress on the Senescence of Trabecular Meshwork Cells

PURPOSE: To investigate the effects of oxidative stress on the senescence of trabecular meshwork (TM) cells and the effect of L-ascorbic acid (LAA) against oxidative stress-induced senescence. METHODS: Primary cultured human TM cells were exposed to 0.05 or 0.1 mM hydrogen peroxide for 30 minutes and incubated for 1 week with or without co-exposure of LAA. Cellular survival, nitrite production, and senescence were assessed with MTT, Griess, and SA-beta-gal assays, respectively. RESULTS: Hydrogen peroxide decreased cellular survival and NO production accompanied increased cellular senescence. LAA did not prevent hydrogen peroxide-induced senescence. CONCLUSIONS: Oxidative stress-induced senescence of TM cells may be related to the dysfunction of trabecular meshwork in glaucoma.