摘要:

ABSTRACTThe renin-angiotensin-aldosterone system is important in the regulation of body fluids. Angiotensin-converting enzyme (ACE) which forms angiotensin II from angiotensin I, is known to be present in human ocular tissue. In rabbits, some topically applied ACE inhibitors including captopril have been shown to reduce IOP with a magnitude and duration comparable to that of topical 0.5% timolol. Captopril in a 50mg single oral dose, which had a significant effect on blood pressure, had no significant effect on IOP over a 4 hour period.

ISSN:8756-3320    

DOI:10.1089/jop.1989.5.1

年代:1989

数据来源: MAL

摘要:

ABSTRACTThere is substantial evidence that prostaglandins (PG's) mediate acute elevations of intraocular pressure (IOP) due to laser irradiation of the iris. In the present study, we determined the optimal laser parameters needed to produce the maximal rise in IOP in anesthetized rabbits. Application of argon laser (0.75 watts, 0.5 sec. duration, and 8 spots of 500 um size) to the iris of pigmented rabbits elicited an acute rise in IOP and miosis accompanied by an increase in aqueous protein concentration. This response was followed by a delayed ocular hypotension that lasted for more than 3 days and returned to baseline by day 5. The onset of ocular hypertension occurred within 15 min. and remained elevated for at least 90 min. The laser induced rise in IOP was related more to the number of laser spots applied to the iris than to the intensity of the total laser energy utilized.Pretreatment with either indomethacin or flurbiprofen produced a dose dependent inhibition of ocular hypertensive response and significantly reduced aqueous protein concentration. Indomethacin (0.01–30 mg/kg) was administered intraperitonially 1 hr. before laser treatment and flurbiprofen (0.03–0.3%) was administered topically 45 and 15 min. prior to laser application. The hypertensive response was reduced by more than 90% of control after both drugs, whereas the delayed hypotension was significantly antagonized only at the highest dose of indomethacin. Neither indomethacin nor flurbiprofen altered the maximum miotic response to laser irradiation of the iris. However, 0.3% flurbiprofen and 30 mg/kg indomethacin significantly increased the recovery rate of the miotic pupil. The results of this study support the contention that argon laser induced ocular hypertension may provide a quantitative assessment of inhibition of prostaglandin mediated respon

ISSN:8756-3320    

DOI:10.1089/jop.1989.5.7

年代:1989

数据来源: MAL

摘要:

ABSTRACTPseudomonas aeruginosaoften persists in ocular infections despite intensive antimicrobial therapy. In this study, gentamicin-resistant small colony variants (SCV) were selectedin vitrofrom three gentamicin-susceptiblePseudomonasisolates by incubation with antibiotic. In the rat comea, SCV were selected from two of these strains by administration of gentamicin either topically or intravenously. The selection of resistant variants may be a contributing factor in the persistence and reactivation frequently associated with ocularPseudomonasinfections.

ISSN:8756-3320    

DOI:10.1089/jop.1989.5.19

年代:1989

数据来源: MAL

摘要:

ABSTRACTThe concentration of the beta-adrenergic blocking agent metoprolol was determined in the blood plasma and aqueous humour after oral administration of the compound. One group (10 cases) was receiving their prescribed continuous therapy and the other group (20 cases) received a single dose of metoprolol. The concentration of metoprolol was usually higher in aqueous than in plasma after continuous administration. This differs significantly from administration of a single dose where the concentration of metoprolol was higher in plasma.The result indicates an ocular accumulation of the drug in chronic systemic treatment.

ISSN:8756-3320    

DOI:10.1089/jop.1989.5.27

年代:1989

数据来源: MAL

摘要:

ABSTRACTThe effects of μ and k opiate agonists were assessed on the pupillary size in normoglycemic and hyperglycemic conditions in mice. The μ agonists used were, morphine (10, 30 and 100 mg/kg), fentanyl (50, 100 and 150 μg/kg) and sufentajop (5, 10 and 20 μg/kg). The highly selective k opiate agonists used were, U-50488H and U-69593 (30 mg/kg). Chronic hyperglycemia was induced by streptozotocin injection (200 mg/kg i.p) 7-8 days before the experiment. Acute hyperglycemia was induced by intraperitoneal glucose (5 g/kg i.p) injection at the time of subcutaneous injection of opiates. In the normoglycemic mice, the μ agonists produced significant mydriasis (P<0.05), while k agonists had no effect on the pupil. However, both acute and chronic hyperglycemic condition did not affect the mydriatic ratio of the μ opiate agonists. These results indicate that μ opiate receptors induce mydriasis in mice and suggest that the hyperglycemia is not the mechanism involved in the opiate induced mydriasis in mice. With the dose of k agonists used, the involvement of k receptors in the pupillary effects in mice were not clear. These results support the hypothesis that hyperglycemia is not the primary mechanism for the altered sensitivity of opiates in the animal models of di

ISSN:8756-3320    

DOI:10.1089/jop.1989.5.33

年代:1989

数据来源: MAL

摘要:

ABSTRACTBefunolol was tested in an animal experiment with 2 cataract models of the Sprague-Dawley-rat. The treatment scheme was designed with 8 different treatment groups, such that befunolol could be tested single and in combination with one or two cataract models. Over the 6 weeks experimental period, slit lamp microscopy and Scheimpflug photography were employed as observation and documentation methods, extensive post-mortem biochemistry was carried out after sacrifice of the animals. Neither the in-vivo observation and documentation nor the biochemistry showed pronounced effects pointing to a cocataractogenic potential of the drug. Slit density enhancing effects were found in combining UV-B irradiation and befunolol treatment. This effect has also been found in other experiments with timolol.

ISSN:8756-3320    

DOI:10.1089/jop.1989.5.45

年代:1989

数据来源: MAL

摘要:

ABSTRACTOcular tissues have the capacity to metabolize arachidonate to prostaglandins and related materials, such as hydroxy arachidonate derivatives (HETEs) which are potent mediators of the inflammatory response. Reactive oxygen species are also present during the inflammatory response, resulting in an altered oxidative environment within the eye. This study was designed to evaluate the possible impact of the oxidant hydrogen peroxide and anti-oxidants, ascorbic acid and glutathione, upon arachidonate metabolism. It was found that hydrogen peroxide was observed to potently inhibit arachidonate metabolism in the cornea, but not in the iris-ciliary body. This might be related to a more efficient detoxification of hydrogen peroxide by iris-ciliary body. Ascorbate appeared to have a general stimulatory influence upon arachidonate metabolism in the iris-ciliary body. In the cornea, ascorbate selectively reduced metabolism to HETE while enhancing the products generated by the cyclo-oxygenase pathway. In both cornea and iris-ciliary body reduced glutathione suppressed conversion of arachidonate to its active metabolites. These observations indicate that arachidonate metabolism in ocular tissues is sensitive to the oxidative environment.

ISSN:8756-3320    

DOI:10.1089/jop.1989.5.51

年代:1989

数据来源: MAL

摘要:

ABSTRACTThe activity of palmityl CoA oxidase, a peroxisomal enzyme, was determined in bovine ocular tissues. Significant levels of activity were found in the iris, ciliary body and pigmented epithelium-choroid but little or no activity was detected in the corneal epithelium, lens capsule-epithelium and retina. Treatment of bovine ciliary epithelial cells with clofibric acid for 72 hours in culture resulted in a several fold enhancement of palmityl CoA oxidase activity. These results suggest that peroxisomal enzymes can be induced in uveal tissues when peroxisome proliferation is stimulated by certain drugs in these tissues.

ISSN:8756-3320    

DOI:10.1089/jop.1989.5.65

年代:1989

数据来源: MAL

摘要:

ABSTRACTThe effects of benzydamine eye drops on the ocular reaction to different irritating stimuli in rabbits are reported. Benzydamine at the concentration of 0.1% reduces inflammatory tissue changes induced by AgNO3burning of the cornea and inhibits the blood-aqueous barrier breakdown due to peripheral iridectomy or laser irradiation of the iris. Benzydamine reduces the aqueous PGE2 concentration to a similar extent as a 0.5% commercially available eye drop formulation of piroxicam. This result is in contrast with previousin vitroresults demonstrating that benzydamine is devoid of any effects on PG synthesis. The possibility that PGE2 reduction is an indirect effect due to other biochemical activities of benzydamine is discussed. In the normal eye benzydamine manifests a local anaesthetic effect which is not accompanied by irritative changes in the anterior segment of the eye, changes in the intraocular pressure or pupillary size. It is suggested that in the clinical use of benzydamine eye drops the local anaesthetic activity may contribute to reducing both the neurogenic component of ocular inflammation and acute pain following injuries to the eye.

ISSN:8756-3320    

DOI:10.1089/jop.1989.5.71

年代:1989

数据来源: MAL

摘要:

ABSTRACTAn attempt has been made in this study to develop a simple, economical and painless method for the delivery of insulin systeraically without using parenteral routes. Insulin was shown to be absorbed effectively into systemic circulation through the eyes. With 0.125% (0.031 mg/25 ul), 1% (0.25 mg/25 ul), and 5% (1.25 mg/25 ul) insulin instilled topically into the eyes, systemic blood concentrations of 1.3 ng/ml, 9 ng/ml, and 24 ng/ml, respectively, could be attained. When 25 ul of 1%, 2% and 5% insulin plus 1% saponin solution were instilled into eyes they reached 63 ng/ml, 89 ng/ml and 195 ng/ml, respectively in the systemic circulation. These results indicate that the systemic absorption of 1% insulin through the eyes can be enhanced at least 7-fold when 1% of the surfactant, saponin, was added to the solution. However, the insulin absorption was not affected by aminopeptidase inhibition nor by the change of pH in the range of 5 to 8. Most importantly, the blood glucose was reduced concomitantly with the increase of blood insulin when 50 μl of 1% insulin in 1% saponin solution was instilled in the eyes. The blood glucose of alloxan-treated diabetic animals reduced drastically from 370 mg % to 185 mg % in 90 min and further to 75 mg % in another 150 min. In normal animals, 25 μl of 1% insulin in 1% saponin reduced blood glucose from 102 mg % to 50 mg % in an hour and blood glucose remained low for at least 3 hrs. These results indicate that insulin can be delivered systeraically through the eyes, particularly with the surfactant enhancers, such as saponin. This new method is economical and simple as compared with parenteral administration and/or minipump implantation. It is hoped that this new method would improve patients' compliancy in using insulin for diabetes treatmen

ISSN:8756-3320    

DOI:10.1089/jop.1989.5.81

年代:1989

数据来源: MAL