A preliminary study of corneal penetration of 125I-labelled idoxuridine liposome

We compared corneal penetration of idoxuridine (IDU) to liposome-encapsulated IDU. Liposomes of phosphatidic acid, phosphatidyl choline, and alpha-tocopherol in a molar ratio 1:8:1 were prepared using the reverse phase evaporation method. New Zealand albino rabbits received either 0.1% solution of I125-labelled aqueous IDU or liposome-encapsulated IDU topically every 2 min for 6 min. Corneal, aqueous, and vitreous samples were assayed for I125 radioactivity at 15 min and at 1, 2, 3, and 6 h following drug application. Our results indicated that corneal penetration of liposomal IDU was significantly increased over the regular form of the drug for a time interval of 6 h.     

Contact Nd:YAG laser for use in oculoplastic surgery

We used a contact Nd:YAG laser with a sapphire tip to perform blepharoplasties in rabbits, and to cut bone in the orbital rim. All procedures were performed easily and without intraoperative hemorrhage.     

Retinal and choroidal detachments: role of magnetic resonance imaging and computed tomography

This article presents MR and CT images of certain inflammatory and neoplastic choroidal and retinal disorders that are associated with retinal and choroidal detachment. The characteristic MR and CT features of retinal and choroidal detachments in many cases can assist ophthalmologists and radiologists in arriving at correct diagnoses of ocular diseases.     

Effect of piroxicam on the blood-retina barrier in experimentally induced diabetes in rats

The effect of piroxicam on the blood-retina barrier was evaluated in rats with experimentally induced diabetes. Diabetes was induced in rats by intraperitoneal injection of streptozocin (STZ). Diabetic rats were divided into two equal groups: those treated with piroxicam, a long-acting platelet inhibitor, and an untreated control group. Vitreous fluorophotometry (VFP) was performed both before and two weeks after induction of diabetes and piroxicam intake. Streptozocin-induced diabetes caused an alteration in the blood-retinal barrier evidenced by an increase in vitreous fluorescein concentration in diabetic rats compared with normal rats. Piroxicam intake did not lead to significant change in vitreous fluorescein concentrations. However, the examination had to be terminated at two weeks because of cataract formation. The piroxicam treated group showed less incidence of lens opacity formation (59.1% compared to 81.8% in the untreated group, p = 0.0006). Piroxicam administration appears to protect the diabetic rat eye against lens opacification.This work was supported in part by U.S. Public Health Service Grants EY02377, EY07541 and EY08137 from the National Eye Institute, National Institutes of Health, Bethesda, MD and by the Juvenile Diabetes Foundation International and Pfizer, Inc.     

Preferential uptake and metabolism of docosahexaenoic acid in membrane phospholipids from rod and cone photoreceptor cells of human and monkey retinas

The uptake, metabolism, and cellular distribution of [3H]docosahexaenoic acid (DHA) in human and monkey retinas were studied with biochemical and autoradiographic techniques. In specimens from two human retina biopsies, incubated for 4 hr or 6 hr with [3H]docosahexaenoic acid (110 nM), 80% of the esterified [3H]fatty acid was recovered in phospholipids and the remainder in triacylglycerols and diacylglycerols. The distribution of [3H]DHA in individual phospholipids (PL) was similar in both retinas, with phosphatidylcholine (PC) and phosphatidylethanolamine (PE) accounting for most of the label. A similar labeling profile was observed in glycerolipids from monkey retina, and after 1 hr of incubation, high labeling of phosphatidic acid (PA, 11%) and phosphatidylinositol (PI, 20%) was observed. In both human and monkey retinas, a preferential uptake of [3H]DHA by photoreceptor cells was revealed by autoradiography. Cone photoreceptors showed a slightly higher density of silver grains in their inner segments than did rod photoreceptors. Photoreceptors accounted for 59% and 79% of the total [3H]DHA taken up by the human and monkey retinas, respectively, the remainder being distributed throughout the neural retina. In conclusion, this study shows for the first time that in human and monkey retinas, DHA is taken up with a high degree of selectivity by photoreceptor cells, and then becomes esterified mainly into phospholipids that will be subsequently utilized for the synthesis of new disc membranes.     

A bent-tipped endolaser probe

I have developed a bent-tipped probe for endolaser photocoagulation that facilitates treatment near the entry site of the instrument.     

Interleukin-12 is detectable in sera of patients with multiple sclerosis — association with chronic progressive disease course?

Multiple sclerosis (MS) is widely accepted as a systemic T- cell-mediated autoimmune disease with a T-helper type-1 (TH-1) profile of cytokine production. We addressed the question whether interleukin-12 (IL-12), as a central mediator of TH-1-cell activities, is detectable in sera of MS patients, and if there is any association with disease activity. We analysed 171 sera of patients with MS and meningitis, and healthy controls. IL-12 p40 protein was detectable at low levels in MS patients (median 43 pg/ml) and controls (median 49 pg/ml). Analysing different disease courses and activities, a significant elevation in stable primary progressive MS cases compared with controls (median 66 pg/ml) was found. IL-12 p40 protein was not detectable in cerebrospinal fluid probes of 10 patients. We conclude that the function of IL-12 in MS depends on expression and degradation of the different proteins. These could act proinflammatory as well as limiting the disease process. Copyright Lippincott Williams & Wilkins     

External drainage of subretinal fluid with a contact Nd:YAG laser

We used a Nd:YAg laser fit with a fiberoptic cord and sapphire tip to drain subretinal fluid externally in patients with rhegmatogenous retinal detachment. The direct contact between the laser and the choroid allowed for controlled cutting and coagulation of the intervening choroidal vasculature. The drainage was successfully achieved with no complication.Supported in part by a grant from Research to Prevent Blindness, Inc., New York City, and by Core grant EY1972 from the National Eye Institute, Bethesda, MD.     

Intravitreal injection of liposome-encapsulated ganciclovir in a rabbit model

The authors determined the intravitreal clearance of liposome-encapsulated ganciclovir. Liposome-encapsulated ganciclovir (84.1 micrograms/0.1 ml) was injected into the vitreous cavity of New Zealand rabbits, which were killed at 24 hours and 7, 14, and 28 days after injection. Total ganciclovir concentrations in the vitreous, up to 28 days, were higher than ID50 (50% inhibitory dose) for different clinical and laboratory strains of viruses belonging to the herpes simplex family.