Effects of L-NAME and timolol on aqueous IL-1beta, IL-6, IL-8, TNF-alpha and NO levels after Nd:YAG laser iridotomy in rabbits.

PURPOSE: Pro-inflammatory cytokines are produced by tissues and play a vital role in the host inflammatory response and uveitis. Nitric oxide (NO) can be produced in large amounts as a response to experimentally-induced uveitis or cytokines. In this study, we measured the levels of pro-inflammatory cytokines such as interleukin (IL)-1beta, IL-6, IL-8, tumor necrosis factor (TNF)-alpha and free-radical in aqueous humor after Nd:YAG laser iridotomy in rabbits, and investigated whether timolol maleate an anti-glaucoma drug, or a NO synthase inhibitor, NG-nitro-L-arginine methyl esther (L-NAME) had an inhibitory effect on these molecules, since L-NAME is a known anti-inflammatory agent in rabbits. METHODS: Bilateral experimental Nd:YAG laser iridotomy (power 7.5 mJ, mode single burst, aiming beam 4) was performed on 18 rabbits under general plus topical anesthesia. Aqueous humor samples were taken by clear corneal paracentesis preoperatively, and 1 and 24 h postoperatively. Six rabbits (12 eyes) were given bilateral topical timolol maleate 0.5% (Timoptic) drop b.i.d. (group 1), six rabbits (12 eyes) received bilateral 0.1 ml subconjuntival injections of L-NAME (150 mg/kg) (group 2), and six rabbits (12 eyes) were treated with topical balanced salt solution (BSS) b.i.d. (control). RESULTS. Preoperative cytokine and NO levels were comparable in the three groups, with no significant differences. In addition, there was no significant difference in baseline cytokine levels between the right and left eyes. In all groups, pre- and postoperative mean IL-1beta levels were below the detection limit of the assay (<5.0 pg/ml). In the control group, postoperative mean IL-6, IL-8 and NO levels were significantly higher after Nd:YAG laser iridotomy than before (for each, p < 0.01). Timolol and L-NAME both inhibited the rise in IL-8 and TNF-alpha levels. Timolol also inhibited the rise in IL-6 but not NO. L-NAME had an inhibitory effect against NO, but not IL-6. CONCLUSIONS: L-NAME has an inhibitory effect on IL-8, TNF-alpha and NO, but not on IL-6. Timolol had inhibitory effects on IL-6, IL-8 and TNF-alpha, but not on NO. These preliminary experimental results might help in assssing the effect of Nd:YAG laser iridotomy in aqueous humor, and to understand the inhibitory effects of timolol and L-NAME against these molecules.

The levels of cytokines and nitric oxide in rabbit vitreous humor after retinal laser photocoagulation.

OBJECTIVE: To determine the levels of nitric oxide (NO) and cytokines such as interleukin 1-beta (IL-1beta), interleukin 6 (IL-6), interleukin 8 (IL-8), and tumor necrosis factor-alpha (TNF-alpha) on vitreous humor following retinal laser photocoagulation. MATERIALS AND METHODS: The rabbits were divided into 3 groups of 4 animals (8 eyes) each. Twelve pigmented rabbit eyes underwent modified grid pattern photocoagulation with a power of 240 mW (group I); 300 mW (group II); and 360 mW (group III). The eyes received 200 burns using a spot size of 200 micro, and duration of 0.2 s. Vitreous humor samples were collected from each eye preoperatively and at 24 and 72 hours after the laser. RESULTS: When compared to preoperative levels, IL-6 levels were increased in all groups; IL-1beta levels were increased significantly only in group III. IL-8 levels were high in groups II and III only at 72 hours (P <0.05). TNFalpha levels were elevated significantly in group II and III only at 24 hours (P <0.05). NO levels were significantly higher than preoperative values in all groups at all times. CONCLUSION: Our results support that especially IL-6, IL-8, and NO levels increase significantly following laser photocoagulation. This preliminary study suggests that IL-6, IL-8, and NO might be dominant contributing factors in the occurrence of the inflammation postoperatively.

Bilateral cataract surgery in adult and pediatric patients in a single session.

PURPOSE: To evaluate the results of bilateral simultaneous cataract surgery in adult and pediatric patients under local or general anesthesia. SETTING: Department of Ophthalmology, Inönü University, Turgut Ozal Medical Center, Malatya,Turkey. METHODS: Eighty-two eyes of 41 patients were included in the study. Twelve of 17 pediatric patients with congenital cataract had bilateral simultaneous lensectomy, posterior capsulotomy, and anterior vitrectomy; 5 patients, aged 10 to 19 years, had bilateral extracapsular cataract extraction (ECCE) with posterior chamber intraocular lens (PC IOL) implantation. Forty-eight eyes of 24 adult patients had bilateral simultaneous ECCE with primary (43 eyes) or secondary (5 eyes) PC IOL implantation. Local anesthesia was administered to 20 adult patients by retrobulbar injection; the other cases were performed using general anesthesia. The procedures were treated as 2 separate surgeries in the same session; care was taken to ensure surgical asepsis. RESULTS: No serious intraoperative complications occurred such as posterior capsule rupture, vitreous loss, endophthalmitis, and anesthesia-related problems. Of patients tested, 84.4% achieved a final best corrected visual acuity of 6/12 or better and 31.0%, of 6/6 or better. CONCLUSIONS: Simultaneous bilateral cataract surgery was not associated with an increased rate of complications, and visual results were good. If strict rules of surgical asepsis are followed, this may be a useful option in a variety of bilateral cases using general or local anesthesia.