Internal eye wall resection in the management of uveal melanoma

Twenty patients with presumed uveal melanoma underwent internal eye wall resection. It was the primary procedure in 13 patients who had tumours within 2 disc diameters of the optic nerve head and was combined with external resection in the remainder. Malignant melanoma was confirmed histologically in 15 patients; the diagnosis was a benign tumour in the other 5. The length of follow-up ranged from 2 to 37 (mean 19) months. In all cases the retina was completely attached at the time of last examination. The visual acuity ranged from 20/40 to hand movements; nine patients had an acuity of 20/400 or better. At the time of writing no metastatic disease or local recurrence had developed in any of the 15 patients in whom malignant melanoma was diagnosed.     

Trans-scleral application of a semiconductor diode laser

We used a diode laser with an output power of 1 W through a fiberoptic light pipe (200 microns diameter) to deliver laser energy through the sclera of pigmented rabbits. Ciliary body destruction occurred with energy levels of 300-400 mW and exposure time of 0.5 sec. Retinal photocoagulation was achieved with energy levels of 200-500 mW in 0.5 sec. Histologic examination of acute lesions demonstrated thermal destruction of ciliary body processes and retina. Chorioretinal scar formation was observed clinically and histologically within 2-3 weeks. Our data indicate that the transscleral diode laser may be used for destruction of the ciliary body processes or peripheral retinal coagulation in pigmented eyes.     

Syphilitic gummatous iridocyclitis

We present a rare case of gummatous syphilitic iridocyclitis. The differential diagnosis, clinical characteristics, and treatment of this ocular disease are discussed.     

Intraocular acyclovir levels after subconjunctival and topical administration.

Substantial levels of acyclovir were detected in the aqueous and vitreous of New Zealand rabbits at various time intervals following subconjunctival injection. Intravitreal penetration of acyclovir after topical application was poor.     

Acute retinal necrosis

Five patients with the acute stages of acute retinal necrosis underwent vitrectomy, with acyclovir in the infusion fluid, and the placement of a 360 degrees scleral buckle after intravenous therapy with acyclovir. Anatomic reattachment was achieved in all patients, and improvement over preoperative visual acuity was obtained in four. Recommendations for the treatment of acute retinal necrosis include a high index of suspicion in healthy patients with retinitis, early diagnosis, early intravenous therapy with acyclovir, early pars plana vitrectomy with the use of intravitreal acyclovir in the infusion fluid, and a 360 degrees scleral buckling procedure.     

Comparative study of three fluorescent dyes for angiography: sodium fluorescein, carboxyfluorescein, and calcein

To compare the characteristics of carboxyfluorescein (CF) and calcein (Calc) with those of sodium fluorescein (Naf), the only fluorescent dye currently in clinical use, we performed angiography in rabbits and primates using these three dyes. The circulation decay time of all dyes was longer in primates than in rabbits. In primates, CF and Calc had longer decay times than Naf. Calc produced the greatest contrast between the choroidal and retinal vasculature. Tissue staining and dye leakage into the vitreous immediately after retinal photocoagulation were minimal with Calc, moderate with CF, and marked with Naf. The limited leakage and longer circulation time of Calc may permit simultaneous angiography and photocoagulation therapy without obscuring the fundus view with leaking dye from the photocoagulated structure.     

Intravitreal liposome-encapsulated gentamicin in a rabbit model. Prolonged therapeutic levels

The authors investigated the effect of liposome encapsulation on the pharmacokinetics of gentamicin after intravitreal injection in albino rabbits, using immunofluorescent assay. Gentamicin was encapsulated into liposomes of phosphatidylcholine, phosphatidic acid, and alpha-tocopherol. The final liposomal suspension contained gentamicin, 10 mg/ml, 95% encapsulated. One eye of each rabbit received an intravitreal injection (100 mg gentamicin per 0.1 ml) of either liposome-encapsulated gentamicin (LEG) or gentamicin in phosphate-buffered saline (Gs). Equilibrium dialysis separated free from encapsulated drug in vitreous samples. The peak free drug concentration was significantly less (P less than .01, unpaired t-test) with LEG than with Gs. Concentrations of free and total gentamicin were significantly greater (P less than .05) with LEG than with Gs at 24, 72, 120, and 192 hr. LEG gave a twofold increase in area under the drug concentration time curve for total drug, and a 1.5-fold increase for free drug when compared to Gs.     

The effect of dietary supplementation with n-3 polyunsaturated fatty acids on the synthesis of interleukin-1 and tumor necrosis factor by mononuclear cells

We examined whether the synthesis of interleukin-1 or tumor necrosis factor, two cytokines with potent inflammatory activities, is influenced by dietary supplementation with n-3 fatty acids. Nine healthy volunteers added 18 g of fish-oil concentrate per day to their normal Western diet for six weeks. We used a radioimmunoassay to measure interleukin-1 (IL-1 beta and IL-1 alpha) and tumor necrosis factor produced in vitro by stimulated peripheral-blood mononuclear cells. With endotoxin as a stimulus, the synthesis of IL-1 beta was suppressed from 7.4 +/- 0.9 ng per milliliter at base line to 4.2 +/- 0.5 ng per milliliter after six weeks of supplementation (43 percent decrease; P = 0.048). Ten weeks after the end of n-3 supplementation, we observed a further decrease to 2.9 +/- 0.5 ng per milliliter (61 percent decrease; P = 0.005). The production of IL-1 alpha and tumor necrosis factor responded in a similar manner. Twenty weeks after the end of supplementation, the production of IL-1 beta, IL-1 alpha, and tumor necrosis factor had returned to the presupplement level. The decreased production of interleukin-1 and tumor necrosis factor was accompanied by a decreased ratio of arachidonic acid to eicosapentaenoic acid in the membrane phospholipids of mononuclear cells. We conclude that the synthesis of IL-1 beta, IL-1 alpha, and tumor necrosis factor can be suppressed by dietary supplementation with long-chain n-3 fatty acids. The reported antiinflammatory effect of these n-3 fatty acids may be mediated in part by their inhibitory effect on the production of interleukin-1 and tumor necrosis factor.     

In vitro production of IL 1 beta, IL 1 alpha, TNF and IL2 in healthy subjects: distribution, effect of cyclooxygenase inhibition and evidence of independent gene regulation

Numerous studies have reported altered in vitro cytokine production in various diseases. In the present study we used specific immunoassays to quantitate production of interleukin 1 beta (IL 1 beta), IL 1 alpha, tumor necrosis factor (TNF) and IL 2 from human peripheral blood mononuclear cells (PBMC). The distribution of cell-associated and secreted cytokines was studied in PBMC of 21 individuals; in response to lipopolysaccharide (LPS) the proportion of cell-associated IL 1 beta ranged from 13% to 56%, for IL 1 alpha 29% to 98%, and for TNF 2% to 17%. In a larger cohort of 32 subjects, the total amount of immunoreactive cytokines produced in response to LPS or phytohemagglutinin was normally distributed within the study group. Mean production of IL 1 alpha in response to LPS was 10.1 ng/ml and exceeded production of IL 1 beta (5.6 ng/ml) and TNF (2.2 ng/ml). The distribution pattern was characterized by high intersubject variability extending over two orders of magnitude and the presence of high and low "producers". Production of IL 1 alpha and IL 1 beta correlated (R = 0.69). In contrast, production of IL 1 beta did not correlate with production of TNF or IL 2. Indomethacin present during stimulation of PBMC increased the amount of IL 1 beta produced and showed a high correlation (R = 0.83) compared to cultures without indomethacin. Thus, low production of IL 1 beta in certain subjects appears not to be due to inhibitable levels of cyclooxygenase products. In a retrospective study, PBMC from 12 subjects who had taken oral cyclooxygenase inhibitors during the preceding 7 days produced 43% more IL 1 beta than subjects who did not take these drugs (p less than 0.05). These studies demonstrate that the amount of cytokine synthesized by PBMC (a) is regulated independently for IL 1, TNF and IL 2; (b) correlates for IL 1 beta and IL 1 alpha; (c) is intrinsic for low and high "producers", and (d) production of IL 1 beta increases with the use of oral cyclooxygenase inhibitors.