Sphingosine-1 phosphate prevents ethanol-induced corneal epithelial apoptosis.

Background: Apoptosis is a programmed cell death in multicellular organisms, found in a wide variety of conditions, including inflammatory process, everywhere in the body, including the cornea and conjunctiva. Aim: To evaluate the effect of a new topical formulation of sphingosine-1 phosphate on preventing apoptosis of the corneal epithelium. Setting: Medical University. Materials and Methods: We tested several formulations suitable for topical application. Twenty-five rabbits were distributed among five groups. Group 1 comprised the controls. In Group 2, 20% ethanol was applied topically for 20 seconds; in Group 3, 50 μM topical sphingosine-1 phosphate was applied 2 hours prior to 20% ethanol application. In Group 4, 200 μM topical sphingosine-1 phosphate was applied 2 hours before the 20% ethanol application. In Group 5, only 200 μM topical sphingosine-1 phosphate was applied. Apoptosis was evaluated using the terminal deoxynucleotidyl transferase biotin-dUTP Nick End Labeling (TUNEL) assay. Pairwise comparisons were performed using t-tests with Scheffe's correction. Data were analyzed using STATA 9.0 statistical software. Results: A suspension of sphingosine-1 phosphate in the presence of Montanox 80 was stable and could be formulated without sonication. Epithelial apoptosis was detected only in Groups 2 and 3. Conclusion: Sphingosine-1 phosphate can prevent ethanol-induced apoptosis in the corneal epithelium of rabbits.

Peribulbar anaesthesia using a combination of lidocaine, bupivocaine and clonidine in vitreoretinal surgery.

PURPOSE: The efficacy and safety of peribulbar anaesthesia was assessed using a combination of lidocaine, bupivacaine and clonidine during eye surgery. METHODS: We prospectively studied 100 vitreo-retinal surgical procedures performed by several surgeons. The exclusion criteria included age below 30 years and, axial length of the orbit above 28 mm. Peribulbar was performed using Hamilton's technique. A mixed anaesthetic solution of equal quantity of lidocaine 2% and bupivacaine 0.5% with clonidine (1 mg/kg) was injected. Patients received a mean volume of 14.5 ml +/- 3.5 of the mixture. Akinesia and analgesia were assessed 15 minutes later by the surgeon. Whenever required, supplemental lidocaine 2% (3 ml) by sub-Tenon infiltration was added by the surgeon. Supplemental injections were given only to patients who failed to develop analgesia. RESULTS: The mean age of patients (male 52%, female 48%) was 66 years +/- 10 (mean +/- SD, range 44-90). The 100 surgical procedures were made up of vitrectomy +/- gas +/- silicone oil (22/100), vitrectomy and lensectomy (6/100), vitrectomy and epiretinal membrane +/- laser coagulation +/- gas +/- silicone oil (35/100), scleral buckling or encircling +/- gas (36/100), and cryosurgery +/- gas (1/100). Analgesia was adequate throughout surgery without any supplementation in 85% of cases and with a sub-Tenon infiltration in 99%. Akinesia was complete in 84%, mild in 12% and absent in 4% of cases. The sub-Tenon injection was performed in 15% of cases. Three patients (3%) were agitated during surgery. No neurologic or cardiac complication was seen. In one patient, the systolic blood pressure decreased from 170 to 110 mmHg, 30 minutes after the institution of the peribulbar block. CONCLUSION: Our results show that peribulbar anaesthesia in the proposed mixture offers excellent analgesia in 85% of patients, and in 99% of the patients when supplemented by a subtenon injection. The current mixture of lidocaine, bupivacaine and clonidine is an excellent alternative to the previously used mixture etidocaine, bupivacaine and hyaluronidase for vitreoretinal surgery. However, a randomized controlled clinical trial is needed to prove the efficacy and safety of these results.