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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of corynanthine tartrate, a selective alpha 1-adrenergic receptor antagonist, were studied on intraocular pressure by pneumatonometry, outflow facility by tonography, and aqueous humor flow by fluorophotometry in laboratory animals. Unilateral topical administration of 5% corynanthine significantly lowered mean IOP (+/- SEM) in rabbits for at least six hours, in ten awake monkeys for six hours, and in ten monkeys anesthetized with ketamine for four hours. The maximum effect in awake monkeys occurred two hours after drug administration, from 15.8 +/- 0.5 mm Hg to 12.7 +/- 0.5 mm Hg, with no substantial change in control eyes. No change in outflow facility was demonstrated in 11 monkeys two hours after 5% corynanthine administration. Aqueous humor flow rates did not change in 12 monkeys up to three hours after drug administration. Corynanthine may act by increasing uveoscleral outflow.
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PMID:Corynanthine and aqueous humor dynamics in rabbits and monkeys. 614 57

Corneal perforation and withdrawal of aqueous humor (paracentesis) represents a practical means for producing controlled trauma to the eye. The sequence of events triggered by paracentesis has been carefully studied by in vivo and in vitro microscopy and other means. These observations have proven especially helpful in elucidating the physiology and pharmacology of ocular trauma. Scanning electron microscopy of the ciliary processes of the rabbit has proven a sensitive indicator of the response to prostaglandin, a mediator of the paracentesis reaction. We used SEM to invetigate changes in the ciliary processes induced by paracentesis. We also examined the opposite eye for a consensual response. The effect of prior treatment with aspirin or nerve block was assessed in both the traumatized eye and the fellow eye. In an untreated animal, a consensual response to trauma was present and demonstrable by scanning electron microscopy. The direct response was more effectively blocked by aspirin than by local anesthesia. Both pretreatments were effective in reducing the consensual reaction.
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PMID:SEM of the ciliary processes after paracentesis. 741 89

The presence of constituents of the renin-angiotensin system (RAS) in ocular tissues and fluids suggests this system is involved in ocular physiology. Angiotensin II (AngII) is the main biological effector of the system, so we measured AngII in plasma and in aqueous humor of the anterior ocular chamber of patients undergoing cataract extraction. Untreated normotensive patients were compared with arterial hypertensive patients taking either diuretics which stimulate the RAS or angiotensin converting enzyme (ACE) inhibitors which reduce the production of AngII. Plasma levels of AngII were higher in patients on diuretics (5.46 +/- 1.04 fmol/ml; mean +/- SEM) than in untreated cataract patients (2.28 +/- 0.32 fmol/ml, p < 0.02), and were very low with ACE inhibitors (0.51 +/- 0.18 fmol/ml). In aqueous humor, AngII was measurable in 7 of 11 patients on diuretics (median 1.1 fmol/ml), and in 6 of 16 normotensive patients (median < 0.55 fmol/ml), but not in aqueous humor of 4 patients receiving enalapril or captopril. These results demonstrate the presence of AngII in the eye but do not exclude either its sequestration in the eye or local production. The possibility of individual measurements of intraocular AngII will permit more precise determination of its role in future studies.
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PMID:Individual measurements of angiotensin II concentrations in aqueous humor of the eye. 771 76

We investigated the effects of long-term instillation of bunazosin hydrochloride--alpha 1 specific adrenergic antagonist--on the aqueous humor dynamics and blood-aqueous barrier in rabbit eyes. We examined intraocular pressure, aqueous flow rate, and blood-aqueous barrier permiability for albumin after four weeks application of 0.05% bunazosin. The effect of bunazosin on blood-aqueous barrier destruction by laser iridophotocoagulation was also examined. During four weeks, bunazosin reduced the intraocular pressure by 1.7 +/- 0.6 mmHg (mean +/- SEM). Continuous application of bunazosin had no significant influence on aqueous flow rate and fluorescein isothiocyanate-labeled rabbit albumin (FITC-Alb) concentration in the anterior chamber. Bunazosin had no effect on the rise of the FITC-Alb concentration after iris photocoagulation, but the intraocular pressure in bunazosin treated eyes was significantly lower than in control eyes one hour after photocoagulation.
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PMID:[Effects of long-term application of bunazosin hydrochloride eye drops on the aqueous flow rate and blood-aqueous barrier permiability in rabbit eyes]. 791 88

The purpose of this study was to investigate the effect of a novel immunomodulator, AS101 [ammonium trichloro(dioxyethelene-O-O') tellurate], in the eye. Lewis rats were injected intravitreally with AS101 at a concentration of 13 micrograms/ml in one eye and BSS in the contralateral eye. Control animals were injected with BSS into the central vitreous of both eyes. Ocular inflammation was evaluated at 20 hours by histology, immunopathology, and by cell count, protein and cytokine measurement in the aqueous humor. At 20 hours, eyes injected with AS101 developed iridocyclitis and mild vitritis versus minimal inflammation and/or protein in contralateral eyes or eyes of control animals (p = 0.0121). The inflammatory infiltrate was mixed in character. Major Histocompatibility Complex (MHC) class II antigens and intercellular adhesion molecules (ICAM-1) were expressed in the anterior segment of eyes injected with AS101. In the aqueous humor of these eyes there were significant quantities of inflammatory cells, protein (mean +/- SEM = 11.2 +/- 2.3 mg/ml) and the cytokine interleukin 6 (IL-6) (450 units/ml) compared with contralateral eyes (p = 0.0005 for inflammatory cells; protein, mean +/- SEM = 1.6 +/- 0.17 mg/ml; IL-6 = 12 units/ml) and both eyes of control animals injected with BSS (p = 0.8955 for inflammatory cells; protein, OD = 1.5 mg/ml, OS = 0.7 mg/ml; IL-6, OD = 8 units/ml, OS = 13 units/ml). AS101 has a local inflammatory effect in the eye. This compound may activate ocular inflammation by releasing cytokines such as IL-6.
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PMID:Ocular inflammation stimulated by the immunomodulator AS101 [ammonium trichloro(dioxyethelene-O-O') tellurate]. 795 13

The penetration of sparfloxacin into the aqueous humor after oral administration was studied in 28 patients undergoing cataract surgery. Each patient received a single, oral dose of 400 mg of sparfloxacin. In eight other patients scheduled to undergo vitreal surgery, multiple daily oral doses were administered for a total amount of 1,000 mg. The aqueous levels were (mean +/- SEM) 0.127 +/- 0.036 microgram/ml to 0.404 +/- 0.159 microgram/ml from two to 24 hours after ingestion. In the vitreous, the mean drug level was 0.840 microgram/ml (range, 0.480 to 2.060 microgram/ml), from 4.3 to 8.0 hours after the most recent oral dose. Blood samples obtained at the same time as vitreous and aqueous taps were assayed by high-performance liquid chromatography. These data demonstrate that therapeutic levels of sparfloxacin may be achieved in noninflamed, noninfected eyes undergoing cataract or vitreous surgery.
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PMID:The ocular penetration of oral sparfloxacin in humans. 812 4

The high bioavailability and low toxicity of fluconazole, a stable, water-soluble, low-molecular-weight bis-triazole antifungal, makes it a good candidate for consideration as a topical ocular agent. The penetration of fluconazole (0.2%) into the corneas and aqueous humors of New Zealand white rabbits was assayed by gas liquid chromatography (GLC). Peak corneal levels occurred essentially immediately at 5 min in the corneas [debrided, 8.2 +/- 1.2 micrograms/g; nondebrided, 1.6 +/- 0.6 microgram/g; (mean +/- SEM)] and at 15 min after application in the aqueous [debrided, 9.4 +/- 2.3 micrograms/ml; nondebrided, 1.6 +/- 0.6 microgram/ml; (mean +/- SEM)]. Estimating from semilogarithmic plots of the data, the halflife (t1/2) in the debrided eyes was 15 min; in the nondebrided eyes, t1/2 was 30 min. A loading dose of a 20-microliter drop per min for 5 min yielded levels of 59.9 +/- 11.3 micrograms/g (mean +/- SEM) in the debrided corneas and 32.4 +/- 1.9 micrograms/ ml (mean +/- SEM) in the corresponding aqueous humor. A regimen consisting of this loading dose followed by one 20 microliters drop/h for 6 h showed 45.9 +/- 3.5 micrograms/g (mean +/- SEM) in the debrided corneas and 8.8 +/- 1.7 micrograms/ml (mean +/- SEM) in the corresponding aqueous. The same regimen yielded values of 3.1 +/- 0.2 micrograms/g in the nondebrided corneas and 1.3 +/- 0.2 micrograms/ml (mean +/- SEM) in the aqueous. Minimal inhibitory concentrations (MIC) at 24 h for yeasts ranged from < 1.25 to 20 micrograms/ml, for hyaline molds from 2.5 to > 20 micrograms/ml, and dematiaceous molds from < 1.25 to > 20 micrograms/ml. Topical fluconazole exhibits pharmacokinetics and selective MICs that merit further evaluation for its ophthalmic use as a topical antifungal agent.
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PMID:Ocular penetration and pharmacokinetics of topical fluconazole. 939 85

The purpose of this study was to investigate the penetration into the aqueous humor of cefuroxime after a single oral dose as cefuroxime axetil. Fourteen patients scheduled for cataract extraction received a single oral dose of cefuroxime axetil corresponding to 500 mg of cefuroxime 2-8 h preoperatively. Aqueous humor samples were obtained at the beginning of the cataract surgery and blood samples were drawn at the time of anesthesia. Cefuroxime levels were determined by high-performance liquid chromatography. The aqueous levels were (mean +/- SEM) 0.48 +/- 0.13 microgram/ml from 3 to 8 h after administration. Serum levels averaged 3.80 +/- 0.58 micrograms/ml. These data indicate that detectable levels of cefuroxime, exceeding the MIC of some bacterial species that frequently cause intraocular infections, may be achieved in uninflamed eyes after a low dose of cefuroxime axetil.
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PMID:Penetration of oral cefuroxime axetil into the human aqueous humor. 921 13

Previously, it had been demonstrated that cataract in diabetic rats can be prevented by systemical administration of the calcium channel blocker verapamil. In addition to that, 0.125% verapamil eye drops were found to significantly reduce the intraocular pressure in ocular hypertensive human subjects. The purpose of this study was to investigate the ocular penetration and elimination of verapamil after topical administration of the drug in rabbits. Two drops of a 0.125% aqueous solution of RS-verapamil hydrochloride (corresponding to a total dose of 125 microg RS-verapamil hydrochloride) were administered into the conjunctival sac. Aqueous humor and blood samples were taken at different times after administration and analysed for drug concentration by combined gas chromatography-mass spectroscopy. Following the instillation of 0.125% verapamil eye drops in a total dose of 125 microg RS-verapamil, mean (+/- SEM) aqueous humor peak levels of 1607 +/- 272 ng/ml were achieved after 20 min. Mean half-life for the elimination from the aqueous humor was 33 min. Topical application of verapamil produced very low serum peak concentrations (10.5 +/- 1.3 ng/ml). The results of our study demonstrate that topically administered verapamil readily penetrates into the anterior chamber leading to aqueous humor drug levels in the microM range without producing serum levels that are high enough to cause cardiovascular side effects.
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PMID:Ocular pharmacokinetics of verapamil in rabbits. 955 Mar 6

Latanoprost (PhXA41, Xalatan) and isopropyl unoprostone (UF-021, unoprostone, Rescula) two new prostanoid derivatives, have been shown to reduce intraocular pressure (IOP) significantly in patients with glaucoma or ocular hypertension. This study was designed to compare the ocular hypotensive effects of latanoprost and unoprostone in cynomologus monkeys with glaucoma and characterizes the prostanoid's mechanisms of action in normal cynomolgus monkey eyes. Intraocular pressure was measured daily at 0, 0.5, and 1 hour and hourly for 5 additional hours during 1 baseline day, 1 vehicle-treated day, and 5 days of therapy with either 0.005% latanoprost or 0.12% unoprostone applied twice daily, at 9:30 AM and 3:30 PM, to the glaucomatous eye of eight monkeys with unilateral laser-induced glaucoma. Outflow facility was measured in six normal monkeys 3 hours prior to dosing and 1 hour after unilateral dosing with either drug. Aqueous humor flow rates were measured in six normal monkeys hourly for 4 hours on 1 baseline day and on 1 treatment day beginning 1 hour after administration of either drug to one eye. Intraocular pressure was significantly (P < 0.005) reduced after the first application for 4 hours with latanoprost and for 2 hours with unoprostone, up to 5.4 +/- 0.8 mm Hg (mean +/- SEM) (latanoprost) and 3.8 +/- 0.5 mm Hg (unoprostone). Intraocular pressure was significantly (P < 0.005) reduced for at least 18 hours following each PM dose of latanoprost. Intraocular pressure was not reduced (P > .05) 18 hours after each PM dose of unoprostone. An enhancement of the ocular hypotensive effect was observed from day 1 to day 5 with repeated dosing of either drug. Latanoprost produced a greater magnitude of IOP reduction for a longer duration of time than unoprostone after each application. Neither drug altered outflow facility or aqueous humor flow rates. Latanoprost and unoprostone appear to reduce IOP in monkeys by enhancing uveoscleral outflow. Latanoprost appears to be more efficacious and potent than unoprostone in reducing IOP in glaucomatous monkey eyes.
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PMID:A comparative study of latanoprost (Xalatan) and isopropyl unoprostone (Rescula) in normal and glaucomatous monkey eyes. 958 40


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