摘要:

ABSTRACTThe purpose of this study was to gather information on the mechanism by which timolol/pilocarpine (TI/PI) combination eyedrops provide additive ocular hypotensive effects. An hypothesis, according to which the combination eyedrops prolong the intraocular permanence of PI as a consequence of decreased aqueous humor secretion induced by TI, was not supported by clear-cut literature evidence. It was thus sought to verify if repeated instillations in albino rabbits of combination TI/PI eyedrops do effectively prolong the turnover of PI. Commercial eyedrops containing 0.68% w/v TI maleate and 2.0% w/v PI hydrochloride, buffered at pH 6.8, and two reference solutions containing PI hydrochloride alone (2% w/v), buffered at pH 5.5 and 6.8, were instilled b.i.d. in albino rabbits for five days. Aqueous humor samples, analyzed after the last treatment, showed that the aqueous humor PI levels observed after administration of the combination eyedrops were significantly higher than those resulting from administration of the reference formulations. When compared with the pH 6.8 reference solution, the pH 5.5 one produced slightly higher and more sustained drug levels in the aqueous humor. The present results appear to confirm the assumption that an increased retention of PI in the aqueous humor is responsible for the additive effects on intraocular pressure reported by several authors for the combination TI/PI eyedrops.

ISSN:8756-3320    

DOI:10.1089/jop.1999.15.1

年代:1999

数据来源: MAL

摘要:

ABSTRACTThe purpose of this study was to examine the actions of a garlic-derived compound, S-allylmercaptocysteine (SAMC) on intraocular pressure (IOP) and to determine the possible involvement of sulfhydryl reactivity, sympathetic neuronal activity and atrial natriuretic peptide (ANP) in the IOP response. Topical, unilateral application of SAMC (20, 100, 200 μg) elicited dose-dependent decreases in IOP. The magnitude of the IOP-lowering effect induced by SAMC was between four to six mmHg. The ocular hypotensive responses were unilateral, peaked at one to three hours and lasted from two to four hours. The IOP-lowering effect by SAMC (100 μg) was enhanced modestly by topical, bilateral pretreatment with a reducing agent, tris(2-carboxyethyl) phosphine (100 μg) which itself produced no change in IOP. No alteration of pupil diameter was observed following topical application of either SAMC or tris(2-carboxyethyl) phosphine. Thus, alteration of sulfhydryl reactivity does not seem to be a major mechanism of action for SAMC. SAMC caused no change of basal and electrically stimulated norepinephrine release in rabbit iris-ciliary bodies, ruling out a prejunctional effect on sympathetic nerve activity. However, SAMC increased the ANP levels in aqueous humor by five-fold. It is concluded that the ocular hypotensive response induced by SAMC in rabbits could involve the elevation of ANP levels in aqueous hum

ISSN:8756-3320    

DOI:10.1089/jop.1999.15.9

年代:1999

数据来源: MAL

摘要:

ABSTRACTAqueous humor dynamics were studied in α-chymotrypsin-induced ocular hypertensive rabbits either by tonographic or two-level constant pressure perfusion techniques. A significant correlation was obtained between the values of outflow facility in α-chymotrypsin-induced ocular hypertensive rabbits as determined by tonography and constant pressure perfusion. The mean value of tonographic outflow facility in ocular hypertensive rabbits was not statistically different from that found in ocular normotensive rabbits. On the contrary, the estimated rate of aqueous inflow in ocular hypertensive rabbits was about 1.5-fold higher than that of ocular normotensive ones. While topical timolol lowered intraocular pressure and aqueous humor inflow in ocular hypertensive rabbits, pilocarpine did not produce any significant effect. Aqueous humor protein was significantly increased in ocular hypertensive eyes. The results of this study show that accurate measurements of outflow facility can be obtained in α-chymotrypsin-induced ocular hypertensive rabbits by tonographic technique. Our data suggest that the long-term ocular hypertension induced by α-chymotrypsin in albino rabbits may be secondary to an increase in the rate of aqueous humor inflow, likely produced by a breakdown of the blood-aqueous barrier. This finding strongly conflicts with the hypothesis of trabecular blockage as the cause of α-chymotrypsin-induced ocular hypertension in this spe

ISSN:8756-3320    

DOI:10.1089/jop.1999.15.19

年代:1999

数据来源: MAL

摘要:

ABSTRACTThe purpose of this study was to evaluate differences in efficacy and safety of latanoprost as monotherapy compared to adjunctive therapy in primary open-angle glaucoma. We reviewed records of 527 patients who were treated with latanoprost as mono- or adjunctive therapy to reduce the intraocular pressure. Each patient was treated at least three months unless they were discontinued due to an adverse event or lack of efficacy. In the monotherapy group (n=49) baseline intraocular pressure of 23.6 ± 5.2 mm Hg fell to 18.4 ± 4.3 mm Hg after 4.4 ± 2.0 months of follow-up; in the adjunctive therapy group (n=39) baseline intraocular pressure of 21.8 ± 5.7 mm Hg fell to 16.7 ± 4.6 mm Hg following 4.3 ± 1.8 months of therapy which was a similar change from baseline for both groups (P>0.9). No differences were noted in the class or number of medicines to which latanoprost could be added including: ß-blockers, α-agonists and topical carbonic anhydrase inhibitors. The reasons for failure with monotherapy were mostly adverse events (10/15 patients) and with adjunctive therapy lack of efficacy (14/16 patients). Latanoprost is similarly effective as monotherapy and as an adjunctive agent in reducing the intraocular pressure. Latanoprost can be added successfully to a variety of classes of glaucoma medicines used commonly as adjunctive

ISSN:8756-3320    

DOI:10.1089/jop.1999.15.29

年代:1999

数据来源: MAL

摘要:

ABSTRACTOur purpose was to study the antiproliferative effect of cytosine arabinoside (Ara-C) on rabbit Tenon's fibroblasts and the efficacy of Ara-C as an adjunctive antifibrosis treatment for glaucoma filtration surgery in the rabbit eye. Rabbit Tenon's fibroblasts were exposed to 1 μg/ml of Ara-C for various time intervals, then cell number and viability was assessed at different time points. Following posterior lip sclerectomy, rabbit eyes were treated with 10 mg subconjunctival Ara-C daily for 7 days, then every other day for 7 days. Rabbit fibroblasts exposed to 1 μg/ml Ara-C for 1 hour showed no significant decrease in cell number compared with control. Continuous or 24-hour incubation of fibroblasts with Ara-C was lethal to the cells. Exposure of cells to Ara-C for 3-, 6-, and 9-hour intervals caused significant reduction of cell proliferation. Pulsed treatment of cells with 6 hour exposure to 1 μg/ml Ara-C every 3 days caused prolonged suppression of cell proliferation. Following posterior lip sclerectomy in rabbits, topical instillation of Ara-C drops at varying concentrations and dosing intervals did not cause any significant lowering of intraocular pressure compared with control eyes, although bleb survival was prolonged in eyes treated with Ara-C (P<0.01). In rabbit eyes treated postoperatively with subconjunctival injections of 10 mg Ara-C every other day for two weeks, the mean intraocular pressure was significantly decreased and the bleb survival time was significantly prolonged (P<0.0067) compared with control eyes. In conclusion, Ara-C inhibits rabbit Tenon's fibroblast proliferationin vitro. Postoperative subconjunctival injection of Ara-C results in improved bleb function after filtration surgery in the rabb

ISSN:8756-3320    

DOI:10.1089/jop.1999.15.41

年代:1999

数据来源: MAL

摘要:

ABSTRACTWe compared the effect on intraocular pressure (IOP) of maximal doses of a topical carbonic anhydrase inhibitor (CAI) at acidic and alkaline pH where it is maximally effective with full systemic CA inhibition in ocular normotensive New Zealand Albino rabbits.Tonometric IOP levels were measured hourly during 3 hour control period. Topical MK-417 (pKa 5.8, 8.3), a close congener of MK-507 (Dorzolamide) was given as a 1.4% solution at pH 4.5 (n=6) and pH 9.2 (n=6). MK-417 was instilled to the left eye with the right eye used as an untreated control. One hour later methazolamide was given intravenously at 10 mg/kg, a dose known to give full inhibition of the enzyme.Control IOP (mm Hg) was 19.12 ± 0.50. One hour following MK-417, the left eye IOP was 13.40 ± 0.70 (pH 4.5) and 13.25 ± 0.70 (pH 9.2). The right eye pressure was unchanged. Methazolamide injection at this time gave no further drop in the left eye IOP at either pH. IOP in the right eye fell to 14.00 ± 0.70 so that 2 hours after methazolamide injection, the 2 eyes had the same pressure.In conclusion, topical CAI in sufficient dose and correct pH yields IOP lowering equivalent to a maximally effective dose of systemic CAI in rabb

ISSN:8756-3320    

DOI:10.1089/jop.1999.15.51

年代:1999

数据来源: MAL

摘要:

ABSTRACTWe performed a study to evaluate the influence of methylcellulose (MC) on the corneal epithelial wound healing. A precise epithelial wound 2.0 mm in diameter and 70 μm in depth was created by an excimer laser on the cornea of a pig's eyeball. After treatment, the eyeballs were cultured in the incubator and perfused with TC-199 medium into the vitreous cavity. Topical MC with eight different combinations of concentrations and viscosities for experimental groups and BSS for the control group were applied on the epithelial defects three times. Wounds were evaluated 24 hours later with fluorescein stain and recorded with a scoring system. All of the experimental groups except one showed a more statistically significant superior wound-healing rate than the control group. MC possesses the effect to accelerate corneal epithelial wound healing

ISSN:8756-3320    

DOI:10.1089/jop.1999.15.59

年代:1999

数据来源: MAL

摘要:

ABSTRACTCooling of the human iris sphincter from 37.5°C to 17.5°C potentiates the concentration response curves of the muscarinic agonist, carbachol. Although EC50value 0.31 μmol/l of the agonist was not significantly affected at the lower temperature, the maximum contraction of the control at 37.5°C was potentiated by 263%. Such potentiation was 272%, 135% and 125% for the dog, horse and pig in sphincter, respectively. Low temperature potentiation of the carbachol can be reversed by warming the tissue to 37.5°C Pretreatment of the tissue with competitive muscarinic receptor blocker, atropine, blocked the contractile action of carbachol at 37.5°C and 17.5°C which resulted in nearly equal KBof ∼ 2 nmol/l, but at 17.5°C, the contraction induced by carbachol was antagonized by atropine with difficulty to give pseudo KBof 67 nmol/l. Ideally, a competitive reversible antagonist is expected to give equal KBvalues for the drug receptor interaction; irrespective of the method of study. The higher KBvalue indicates a functional antagonism of the agonist activated cascade by the blocker. Clinical implications of the drug antagonism at low temperatures are

ISSN:8756-3320    

DOI:10.1089/jop.1999.15.65

年代:1999

数据来源: MAL

摘要:

ABSTRACTTroglitazone is a new antidiabetic drug with a combined chemical structure of thiazolidinedione and α-tocopherol like structure (chroman ring). We evaluated the effect of troglitazone on the morphological and biochemical changes in rat lenses cultured with galactose. Culturing in 30 mM galactose medium for 48 hrs resulted in vacuole formation in the cortex of lens equator (early phase of cataract). A significant amount of galactitol accumulation and lipid peroxide formation were also observed in lenses exposed to galactose. These morphological and biochemical changes associated with galactose were inhibited by 2 or 20 μM troglitazone present in the galactose medium. These results confirm the previous finding that troglitazone delayed the formation of cataract in rats fed a galactose diet. The anticataract effect of troglitazone was discussed in terms of antioxidant property of the dru

ISSN:8756-3320    

DOI:10.1089/jop.1999.15.73

年代:1999

数据来源: MAL

摘要:

ABSTRACTAlthough 1% atropine effectively slows myopia progression, it is associated with adverse effects, including photophobia, blurred near vision, and poor compliance. We investigated whether lower doses of atropine would control myopia progression. One hundred and eighty-six children, from 6 to 13 years of age, were treated each night with different concentrations of atropine eye drops or a control treatment for up to 2 years. The mean myopic progression in each of the groups was 0.04 ± 0.63 diopter per year (D/Y) in the 0.5% atropine group, 0.45 ± 0.55 D/Y in the 0.25% atropine group, and 0.47 ± 0.91 D/Y in the 0.1% atropine group. All atropine groups showed significantly less myopic progression than the control group (1.06 ± 0.61 D/Y) (p−1.0 D/Y). In contrast, only 8% of the control group showed no myopic progression and 44% had fast myopic progression. These results suggest that all three concentrations of atropine had significant effects on controlling myopia; however, treatment with 0.5% atropine was the most effe

ISSN:8756-3320    

DOI:10.1089/jop.1999.15.85

年代:1999

数据来源: MAL