摘要:

ABSTRACTEffects of L-arginine and some related compounds on the intraocular pressure recovery (IOPR) and ocular blood flow in rabbits had been studied. It was found that L-arginine (RVC-579) and Nα-benzoyl-L-arginine ethyl ester (RVC-578) delayed the IOPR markedly. The IOPR of the contralateral non-treated eye was delayed to the same extent as the treated eye. The effects of closely related congeners L-(+)-canavanine (RVC-581) and L-homoarginine (RVC-580) on the IOPR were qualitatively similar to RVC-579 and RVC-578 but less effective. RVC-578 was found to increase the blood flow significantly in ciliary body, retina and choroid. On the other hand, NG-nitro-L-arginine, a nitric oxide (NO) synthase inhibitor, reduced the blood flow in choraid at 60 and 120 min after drug administration and did not increase the blood flow in iris, ciliary body and retina. These results indicate that L-arginine and its derivative are capable of lowering the IOP possibly through the formation of nitric oxide to relax the blood vessel and to reduce the IOP as a result

ISSN:8756-3320    

DOI:10.1089/jop.1995.11.1

年代:1995

数据来源: MAL

摘要:

ABSTRACTA novel technique is described in which the effect of the β-adrenoceptor antagonists timolol and carteolol, and the vasodilators sodium nitroprusside (SNP) and verapamil on intraocular pressure (IOP) and the distribution of ocular flow in the bovine arterially perfused eye is investigated using radiolabelled microspheres. At maximum IOP-reducing dose timolol was found to significantly reduce perfusion in the choroid and, at higher dose, it was found to significantly reduce perfusion in the iris. By contrast, a maximal IOP-reducing dose of carteolol markedly reduced perfusion in the iris, ciliary body and choroid. Vasoconstriction induced by carteolol was not inhibited by the α-antagonist phentolamine. Against a background of vascular tone induced by noradrenaline, SNP and verapamil were found to significantly increase perfusion in the iris, ciliary body and choroid. The effects of these drugs upon the vasculature of the bovine perfused eye are varied and complex and may not bear a direct relationship to their ocular hypotensive effec

ISSN:8756-3320    

DOI:10.1089/jop.1995.11.11

年代:1995

数据来源: MAL

摘要:

ABSTRACTThis study investigated the effects of apraclonidine hydrochloride 1% eye drops on blood-aqueous barrier in 108 pigmented rabbits. The effects of pretreatment with dapiprazole and yohimbine, and a comparison with clonidine 0.125% eye drops are also reported. The disruption of blood-aqueous barrier was obtained by argon laser burning of the iris. The degree of permeability of the barrier was deduced by the amount of proteins in aqueous humor 60 min after laser application. Intraocular pressure and pupil diameter were also studied.Protein content in aqueous humor was 0.72 ± 0.26 g/l in control rabbits that did not receive any treatment; 5.98 ± 4.23 g/l in rabbits instilled with placebo eye drops and treated by laser burning of iris; 0.43 ± 0.25 g/l in rabbits that received apraclonidine eye drops prior to laser burning; 2.19 ± 1.3 g/l in rabbits that received apraclonidine eye drops immediately after laser application; 0.35 ± 0.08 g/l in rabbits that received apraclonidine 1% eye drops both before and after laser application.Rabbits treated with clonidine 0.125% had a protein content in aqueous humor of 5.45 ± 2.08 g/l after laser application. Dapiprazole 0.5% eye drops prior to apraclonidine led to a protein content in aqueous humor of 1.93 ± 2.13 g/l; yohimbine 0.3% eye drops prior to apraclonidine led to a protein content of 0.70 ± 0.40 g/l. Protein content in aqueous humor was 0.93 ± 0.36 g/l, 0.82 ± 0.899 g/l and 1.68 ± 1.39 g/l in rabbits treated with yohimbine 0.3,0.6 and 1.2 mg/kg i.v. and then with apraclonidine 1% eye drops.In one group of rabbits, the penetration into the aqueous humor of Evans blue injected intravenously was also studied. Evans blue content in aqueous humor was 0.03 ± 0.08 mg/100 ml in control rabbits; 0.92 ± 0.53 mg/100 ml in placebo rabbits treated by laser; and 0.28 ± 0.19 mg/100 ml in apraclonidine rabbits treated by laser.Apraclonidine eye drops led to a decrease in IOP and prevented IOP rise following argon laser application. Placebo treated rabbits had a 20% increase in IOP following laser application. Apraclonidine-treated eyes showed mydriasis and blanching of the conjunctiva. These effects were not affected by pretreatment with dapiprazole or yohimbine.In these experiments, the treatment with apraclonidine 1% eye drops completely protected the blood aqueous barrier from the disruption caused by laser burning of the iris. The protection was less effective when apraclonidine was applied after l

ISSN:8756-3320    

DOI:10.1089/jop.1995.11.25

年代:1995

数据来源: MAL

摘要:

ABSTRACTDipivefrin hydrochloride is a lipophilic prodrug for epinephrine hydrochloride, allowing lower concentration of the drug to achieve the same intraocular pressure lowering effect and having also less harmful effects than epinephrine hydrochloride. However, harmful effects have been associated also with the use of dipivefrin and here we report of a case of corneal vascularization during long-term use of dipivefrin.

ISSN:8756-3320    

DOI:10.1089/jop.1995.11.37

年代:1995

数据来源: MAL

摘要:

ABSTRACTIn an effort to develop a long-term topically active tear stimulant, it was important to determine if tolerance developed following the repeated instillation of N,N-Dimethyl-2-phenylethylamine hydrochloride (AF2975) to the albino rabbit eye. New Zealand white rabbits were administered AF2975 (0.15 %) twice a day (9 am and 4:30 pm) for 10 days. The right eye received the drug solution (50 μl) and the left eye received an equal volume of the vehicle. Prior to dosing and at the end of first and last dose (10 and 60 minutes post-dosing), protein secretion was measured with the use of Schirmer tear test strips placed under the lower lid of each eye for five minutes. The strips absorbed tears from which protein was extracted. Eyes treated with AF2975 showed a statistically significant % increase in protein release compared to baseline values. Control eyes did not show statistically significant increases over baseline. A comparison of % changes from baseline in protein secretion rates after the first and last dose showed no significant differences in either treated or control eyes at 10 and 60 minutes postdosing. These results indicate that tolerance does not occur for protein secretion of topically administered AF2975 (0.15%) following a twice a day dosing schedule for 10 days to the rabbit eye

ISSN:8756-3320    

DOI:10.1089/jop.1995.11.41

年代:1995

数据来源: MAL

摘要:

ABSTRACTTo determine the intraocular concentrations of Mitomycin C (MMC) after extraocular application, we used pigmented rabbits and placed sponges soaked with MMC under the conjunctiva on top of the intact episclera. First, we soaked the sponges with volumes ranging from 0.025 ml to 0.3 ml of the solution containing MMC and sampled aqueous humour after 30 minutes. The concentrations, as determined by high performance liquid chromatography, did not correlate to the amount of MMC given. Then, we soaked the sponges with different concentrations of MMC with a volume of 0.1 ml and sampled aqueous humour, vitreous humour and sclera after 60 minutes. The concentrations of MMC were higher in the vitreous than in the aqueous, and, relative to these values, very high in the sclera. These results indicate that the amount of MMC reaching the interior of the eye after standard extraocular application may be highly variable, and that the concentrations of MMC in the sclera and formed vitreous can be considerably higher than in the aqueous humour.

ISSN:8756-3320    

DOI:10.1089/jop.1995.11.49

年代:1995

数据来源: MAL

摘要:

ABSTRACTOfloxacin 0.3% ophthalmic solution or ointment was administered preoperatively to 13 patients undergoing cataract surgery. Mean drug concentrations in conjunctival biopsies were 2.62 and 6.55 μg/gm and in aqueous humor samples were 0.36 μg/mL and 0.43 μg/mL, for ointment and solution respectively. Mean conjunctival concentrations of ofloxacin achieved MIC90values for 419 gram-positive and gram-negative organisms previously analyz

ISSN:8756-3320    

DOI:10.1089/jop.1995.11.57

年代:1995

数据来源: MAL

摘要:

ABSTRACTProliferative vitreoretinopathy (PVR) is the most severe complication of retinal detachment surgery, occuring approximately in one out often operated eyes. The proliferation of retinal pigment epithelial (RPE) cells and fibroblasts is a cornerstone in the pathogenesis of PVR. Since inhibitory peptides may take a part in the feedback mechanism underlying this proliferation, we assesed the effect of synthesized epidermal dipeptide, pyroglu-glyOH (EDP), on the proliferation of RPE cells and fibroblasts in vitro. The maximum inhibitory effect of EDP on the RPE cells was reached at concentrations ranging from 1.07*10−13to 1.07*10−15M. Its inhibitory effect on fibroblasts followed a similar pattern at all concentrations applied, 1.07*10−6to 1.07*10−15M. These results enhance the possibility that PVR may be due to an imbalance of inhibition/disinhibition mechanism under participation of several regulatory molecules like EDP. EDP might have the potential for reducing the risk

ISSN:8756-3320    

DOI:10.1089/jop.1995.11.65

年代:1995

数据来源: MAL

摘要:

ABSTRACTExogenous prostaglandins (PGs) have been shown to inhibit dopamine (DA) release from the rabbit retina via an effect on presynaptic EP3-receptors. In the present study, we investigated the possible involvement of cyclic AMP in DA release and in the prostanoid receptor mediated regulation of DA release from the neural retina. Both forskolin and 8-bromo-cyclic AMP enhanced field stimulation-evoked [3H]DA release from isolated, superfused rabbit retinas without affecting basal tracer efflux suggesting that presynaptic cyclic AMP may be involved in the pathway leading to DA release. Forskolin attenuated inhibition of evoked [3H]DA release caused by low but not high concentrations of PGE2. Both PGE2and sulprostone had no significant effect on basal cyclic AMP levels but inhibited forskolin-stimulated cyclic AMP formation. Furthermore, sulprostone was more potent than PGE2in attenuating forskolin-activated cyclic AMP production. The inhibition of forskolin-elevated cyclic AMP levels caused by PGE2was, however, unaffected by the EP1-receptor antagonist, AH6809. We conclude that the regulation of DA release by presynaptic prostanoid EP3-receptors may be mediated, at least in part, through an inhibitory effect on adenylyl cyclase.

ISSN:8756-3320    

DOI:10.1089/jop.1995.11.73

年代:1995

数据来源: MAL

摘要:

ABSTRACTSMB (sodium monomethyl trisilanol orthohydroxybenzoate) is an organic complex of silicium and salicylate and the main component of a collyrium used in lens transparency abnormalities. Biotransformation and penetration of salicylate in the whole eyeball have been investigatedin vivoafter repeated instillations of those14C-radiolabeled eyedrops. We also studied more accurately the salicylate diffusion within the lens underex vivoconditions.In vivoexperiments demonstrated that 8 to 48 hours after the last instillation, radioactivity was detectable in most tissues and remained stable except in the chorioretina. The following gradient of distribution was observed: conjunctiva>cornea>iris-ciliary body>chorioretina>lens>vitreous body>aqueous humor>>plasma and blood. The diffusion of the radiolabeled compound in lens fibres was low, but a more important retention was observed in lens capsule. Though salicylate-metabolizing activities have been demonstrated in ocular tissues, no biotransformation could be detected under our experimental conditions. The lens SA-biotransformation activity was reported to be low and we can most probably consider that, in ourex vivopharmacokinetic study, the lens metabolite amounts were negligible compared with the salicylate levels. Under such conditions, results showed that the salicylate reached a steady-state between 6 and 12 hours of incubation, characteristic of a passive diffusion mechanism. Quantitative image analysis of lens section autoradiograms revealed a more intense labeling of the anterior part of the lens and suggests that the lens epithelium may facilitate the salicylate diffusion. Furthermore, renal excretion is important since 40 % of the administered eyedrops were eliminated during the study period.

ISSN:8756-3320    

DOI:10.1089/jop.1995.11.83

年代:1995

数据来源: MAL