Trimetazidine for prevention of induced ischemia and reperfusion of guinea pig retina.

OBJECTIVE: Trimetazidine (TMZ) has been used to protect against ischemia/reperfusion (I/R) injury of many tissues. We aimed to evaluate the effect of TMZ during retinal I/R in a guinea pig model. STUDY DESIGN/PATIENTS AND METHODS: An experimental study in retinal I/R. Three groups of five guinea pigs were studied to include a control, placebo, and drug test groups. Prior to the application of 90 minutes of high intraocular pressure (IOP) to induce retinal ischemia followed by 24 hours of reperfusion, we applied intraperitoneal saline to the placebo group and 3 mg/kg of TMZ for the drug test group and repeated the injections at intervals of six hours for four cycles. Both eyes of the animals were enucleated at the end of the reperfusion period. Biochemical assay and histopathologic evaluation was performed on one randomly selected eye of each animal. The level of retinal-free malondialdehyde (MDA) and retinal layer thicknesses were determined and comparisons were then made with the control group. RESULTS: The mean free MDA level increased in the placebo group (P = 0.006) but not in the drug group (P > 0.05). We observed polymorphonucleated leukocyte infiltration, retinal edema and hydropic degeneration in the retina of the placebo group. However, significant histopathologic change was not observed in specimens of the drug group. CONCLUSIONS: This study suggests TMZ has a beneficial effect on retinal lipid peroxidation and histopathologic changes due to I/R injury.

Octreotide reduces ischaemia-reperfusion injury in the retina.

PURPOSE: To investigate the role of octreotide on retinal lipid peroxidation and histopathological changes during ischaemia/reperfusion (I/R). METHODS: Three groups of seven pigmented guinea pigs each were formed. These represented a control group, an ischaemia group and an ischaemia/octreotide group. One eye of each animal was selected for histopathological evaluation and the other for biochemical assay. Bilateral pressure-induced retinal ischaemia was instigated for 90 min and was followed by 24 hours of reperfusion. Animals in the ischaemia/octreotide and ischaemia groups received either 10 micro g/kg of octreotide or saline, repeated five times at 6-hourly intervals, with the first dose administered 15 min prior to the ischaemic insult. Retinal malondialdehyde (MDA) levels and the thickness of the retinal layers were measured. These were compared with equivalent measurements of the control group. RESULTS: The mean MDA level increased in the ischaemia group (p < 0.01) but not in the octreotide group (p > 0.05). Significant increases in the thickness of the overall retina (p < 0.01), inner retina (p < 0.05) ganglion cell layer (p < 0.01) inner plexiform layer (p < 0.01) and inner nuclear layer (p < 0.01) were observed in the ischaemia group. No significant difference in thickness was found in any of the layers in the ischaemia/octreotide group. CONCLUSION: Octreotide reduces the increases in retinal MDA levels and retinal thickness observed during I/R.

Effect of Octreotide on experimental corneal neovascularization.

PURPOSE: To examine the ability of subcutaneously administered Octreotide ( a long acting somatostatin analoque) to serve as an inhibitory agent for corneal neovascularization in eyes of Wistar Albino rats. METHODS: Neovascular growth into the corneas of all the animals was induced by silver nitrate cauterization. Half of the animals which were randomly selected for the Octreotide group received 30 micrograms systemic Octreotide for 7 days. The treatment was initiated on the same day as chemical cauterization. The rest of the animals (control group) received no treatment. Slit lamp and histopathologic examination of the corneas of both groups were performed at the end of the study period. RESULTS: It was observed that the corneal neovascularization and histopatologic scores of the Octreotide group were significantly lower than those of the control group (p < 0.001, p < 0.01). CONCLUSION: Systemic administration of Octreotide inhibits the corneal neovascular response in a rat model.

Penetration of oral and topical ciprofloxacin into human aqueous humor.

PURPOSE: This study was planned to investigate the penetration of ciprofloxacin into aqueous humor following oral and topical application as a prophylactic antimicrobial agent. METHODS: Forty-six patients undergoing cataract surgery were randomly divided into two groups. In the first group, the patients received 500 mg oral ciprofloxacin eight hours before surgery and in the second, 5 drops of 0.3% ciprofloxacin were applied to the patients every twenty minutes, starting 100 minutes before the surgery. By paracentesis, aqueous samples were taken just before the operation so the interval between the first topical application and paracentesis was 100 minutes. RESULTS: The mean concentration of ciprofloxacin in aqueous humor was 0.63+/-0.29 microg/ml in the first group. The concentration was 0.69+/-0.30 microg/ml in the second group. Both of these mean concentrations were higher than the levels of MIC90 of S.aureus , S. epidermidis, P. aeruginosa and Gram (-) bacteriae. CONCLUSION: As a result, both topically and orally applied ciprofloxacin achieved a significant aqueous concentration. Each route studied might be suitable for surgical prophylaxis or treatment of infections.

Anthrax as the cause of preseptal cellulitis.

Anthrax is an infectious disease caused by Bacillus anthracis. It is primarily a disease of domestic animals such as cattle, goats, and sheep; but humans can rarely be infected by contact with infected animals or contaminated animal products. Our case is a 4-year-old boy who was initially diagnosed as preseptal cellulitis, but later he showed the characteristic anthrax lesions with a black necrotic eschar. Scrapings from the necrotic tissue showed gram positive rods and culture grew Bacillus anthracis. The patient responded to intravenous administration of penicillin G, and the lesions resolved, leaving a scar on the right upper eyelid. Eyelid involvement of anthrax is rarely seen in clinical practice, but should be considered in differential diagnosis.

Effect of topical apraclonidine on flow properties of central retinal and ophthalmic arteries.

To investigate the acute effects of topically administered 1% apraclonidine hydrochloride on blood velocity and resistance parameters of central retinal and ophthalmic arteries, the vessels were studied by color Doppler ultrasonography during baseline and at the time of peak effect of apraclonidine in 20 healthy volunteers. After medication, significant decrease in peak systolic, peak diastolic, mean flow velocities and increase in resistive and pulsatility indices of ophthalmic artery were observed. Blood velocity and resistance parameters of central retinal artery didn't change significantly. In conclusion, topically used apraclonidine was thought to change the blood velocity and resistance parameters of ophthalmic artery as a result of its local vasoconstrictory effect on the anterior segment branches of ophthalmic artery.

Decreased retinal blood flow in retinitis pigmentosa.

OBJECTIVE: To determine alterations in retinal blood flow in retinitis pigmentosa (RP). DESIGN: Case-control study. SETTING: Ophthalmology department of a university-affiliated hospital in Elazig, Turkey. SUBJECTS: Ten patients (20 eyes) with typical RP and 22 age-matched volunteer subjects (22 eyes) with no history of ocular or systemic disease. MAIN OUTCOME MEASURES: Central retinal artery peak systolic and diastolic blood flow velocity (measured by means of colour Doppler imaging), resistance index and pulsatility index. RESULTS: The mean peak systolic and diastolic flow velocity values were significantly lower in the study group than in the control group (4.96 +/- 1.3 vs. 11.11 +/- 1.5 cm/s [p < 0.00001] and 2.15 +/- 0.4 vs. 3.40 +/- 0.9 cm/s [p < 0.0001] respectively). The mean resistance index value was significantly lower in the study group (0.55 +/- 0.05) than in the control group (0.71 +/- 0.06) (p < 0.0001), as was the mean pulsatility index value (0.94 +/- 0.18 vs. 1.45 +/- 0.36) (p < 0.00001). CONCLUSIONS: Decreased retinal blood flow is an important feature of RP.