[Investigations on a prostaglandin-like substance in the humor aqueous in patients with glaucoma (author's transl)].
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Aqueous Humor↗
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Value of PCR for detection of Toxoplasma gondii in aqueous humor and blood samples from immunocompetent patients with ocular toxoplasmosis.
Toxoplasma gondii infection is an important cause of chorioretinitis in the United States and Europe. Most cases of Toxoplasma chorioretinitis result from congenital infection. Patients are often asymptomatic during life, with a peak incidence of symptomatic illness in the second and third decades of life. Diagnosis is mainly supported by ophthalmological examination and a good response to installed therapy. However, establishment of a diagnosis by ophthalmological examination alone can be difficult in some cases. To determine the diagnostic value of PCR for the detection of T. gondii, 56 blood and 56 aqueous humor samples from 56 immunocompetent patients were examined. Fifteen patients with a diagnosis of ocular toxoplasmosis had increased serum anti-T. gondii immunoglobulin G levels but were negative for anti-T. gondii immunoglobulin M (group 1), and 41 patients were used as controls (group 2). Samples were taken before antiparasitic therapy was initiated, and only one blood sample and one aqueous humor sample were obtained for each patient. Single nested PCRs and Southern blot hybridization were performed with DNA extracted from these samples. The results obtained showed sensitivity and specificity values of 53. 3 and 83%, respectively. Interestingly, among all patients with ocular toxoplasmosis, a positive PCR result with the aqueous humor sample was accompanied by a positive PCR result with the blood sample. This result suggests that ocular toxoplasmosis should not be considered a local event, as PCR testing of blood samples from patients with ocular toxoplasmosis yielded the same result as PCR testing of aqueous humor samples. PCR testing may be useful for discriminating between ocular toxoplasmosis and other ocular diseases, and also can avoid the problems associated with ocular puncture.
Adolescent↗
Circadian variations of transforming growth factor-beta2 and basic fibroblast growth factor in the rabbit aqueous humor.
PURPOSE: To compare levels of transforming growth factor-beta2 (TGF-beta2) and basic fibroblast growth factor (bFGF) in the ocular fluids of rabbits at various times of the day. METHODS: Seventy-two young adult New Zealand albino rabbits were entrained to a daily 12-hour light (6 AM to 6 PM) and 12-hour dark cycle. Eight rabbits were sacrificed at each of 6 time points: 4 AM, 8 AM, noon, 4 PM, 8 PM, and midnight. Under an acute 24-hour constant dark condition, 8 additional rabbits were sacrificed at each of 3 time points in the accustomed light period (8 AM, noon, and 4 PM). Samples of aqueous humor and vitreous humor were collected from both eyes. Using enzyme immunoassay, samples from one eye were assayed for total TGF-beta2 and active form of TGF-beta2 and samples from the other eye were assayed for bFGF. Concentrations at various time points were analyzed using one-way ANOVA and post-hoc Bonferroni t-test for multiple comparisons. RESULTS: Aqueous humor levels of total TGF-beta2, active TGF-beta2, and bFGF changed during the 24-hour period. Total TGF-beta2 and bFGF levels increased between 4 AM and 8 AM. Active TGF-beta2 level increased between 8 PM and midnight. Similar patterns of changes were found when considering aqueous humor samples collected under the acute constant dark condition. In the vitreous humor, total TGF-beta2, active TGF-beta2, and bFGF remained unchanged throughout the 24 hours. CONCLUSIONS: Endogenous circadian rhythms of total TGF-beta2, active TGF-beta2, and bFGF occur in the rabbit aqueous humor. These two extracellular signaling molecules may be associated with specific physiological functions in the anterior segment according to the time of the day.
Animals↗
Oxidative stress markers in aqueous humor of glaucoma patients.
PURPOSE: Oxidative stress and antioxidant status in eye tissues may be associated with glaucomatous damage. The aim of this study was to establish the antioxidant status of aqueous humor of patients with primary open-angle glaucoma. For this purpose the authors measured the total reactive antioxidant potential (TRAP) and the activities of the antioxidant enzymes superoxide dismutase (SOD), catalase, and glutathione peroxidase. DESIGN: Case control study. METHODS: Aqueous humor was obtained at the time of surgery from 24 patients with glaucoma and 24 cataract patients; TRAP was measured by chemiluminescence. Activities of the antioxidant enzymes were measured spectrophotometrically. Superoxide dismutase activity was determined by inhibition of the rate of adrenochrome formation at 480 nm. Catalase activity was evaluated by decrease of H(2)O(2) absorbance at 240 nm. Glutathione peroxidase (GPx) activity was determined following nicotinamide adenine dinucleotide phosphate oxidation at 340 nm. RESULTS: Total reactive antioxidant potential value of the cataract group was 124 +/- 5 micromol/l Trolox. This value was significantly decreased, by 64%, in glaucoma patients. An increase of 57% in SOD activity was observed in glaucoma patients when compared with cataract patients (41.7 +/- 2.7 U SOD/ml). Glutathione activity was threefold higher in glaucoma patients than in the cataract group (6.1 +/- 0.6 U/ml). No significant changes were found in catalase levels. CONCLUSIONS: Oxidative stress may lead to an induction of antioxidant enzymes and contribute to TRAP decrease. Superoxide dismutase, GPx activities, and TRAP may be useful oxidative stress markers in aqueous humor of glaucoma patients.
Adult↗
Development of an HPLC method for determining the alpha 2-adrenergic receptor agonist brimonidine in blood serum and aqueous humor of the eye.
A procedure for determining brimonidine [5-bromo-6-(2-imidazolidinylideneamino) quinoxaline] in biological samples using a reversed-phase isocratic HPLC method is described. The application in blood serum and eye aqueous humor of patients treated with the Alphagan ophthalmic solution was carried out by enrichment of samples in brimonidine with solid-phase liquid extraction. Brimonidine reached maximum levels in aqueous humor and serum within 2-2.5 h, whereafter a declining pattern was obtained. An approximate 50% level of brimonidine was identified in serum at 12 h after ocular administration, whereas in aqueous humor this percentage was determined after a period of 4-5 h.
Adrenergic alpha-Agonists↗
Analysis of aqueous humor in ocular toxoplasmosis: detection of low avidity IgG specific to Toxoplasma gondii.
Using a modified enzyme-linked immunosorbent assay that included dissociation of antigen antibody complexes with 6M urea solution, we analyzed the avidity of Toxoplasma-specific IgG in aqueous humor and serum samples from 24 patients with toxoplasmic chorioretinitis. As a control, we studied aqueous humor and serum samples from 14 cataract patients without history of uveitis and serum samples from 10 patients with recent primary systemic toxoplasmic infection without ocular lesions. IgG avidity was markedly lower in aqueous humor samples from patients with toxoplasmic chorioretinitis than in serum samples, despite those samples presenting higher levels of Toxoplasma-specific IgG than in serum samples. The detection of the low-avidity Toxoplasma-specific antibodies can offer a valuable aid to make a specific etiologic diagnosis and perhaps contribute to understand the pathogenic mechanisms of ocular toxoplasmosis.
Adolescent↗
A review of the influence of aqueous humor on immunity.
Regulation of immunity within the immune-privileged ocular microenvironment is a dynamic interaction of anatomical features, factors, and cells that work toward suppressing the induction inflammation. Immunosuppressive neuropeptides found in aqueous humor are central to this immunoregulation. These neuropeptides are alpha-melanocyte-stimulating hormone, vasoactive intestinal peptide, calcitonin gene-related peptide, and somatostatin. Along with transforming growth factor-beta2, the neuropeptides target specific cells and pathways in innate and adaptive immunity. These aqueous humor factors prevent pathogen-induced inflammation and activation of Th1 cells, while promoting induction of regulatory T cells. Therefore, the ocular microenvironment, through the constitutive production of immunosuppressive factors found in aqueous humor, maintains immune privilege by manipulating regional innate and adaptive immunity away from inflammatory responses.
Aqueous Humor↗
[Changes in the antioxidant system of the aqueous humor, lens and erythrocytes after sulfur hexafluoride application to the vitreous of rabbits].
AIM: To determine the activity of superoxide dismutase, catalase and the concentration of malondialdehyde (MDA) in aqueous humor, lens and red blood cells after application of sulfur hexafluoride (SF6) into vitreous of rabbits. MATERIAL AND METHODS: 0.5 ml of 100% SF6 was injected into the vitreous of 24 rabbits of New Zealand race. The animals were randomly divided into 3 groups (of 8 rabbits each) depending on the observation day: group 1-2nd day of experiment, group 2-7th day and group 3-14th observation day. The control group (gr. 0) consisted of 6 rabbits that did not undergo any operations. Activity of superoxide dismutase, catalase and MDA concentration were determined in aqueous humor, lens and systemic blood erythrocytes. RESULTS: On the 7th day of observation an increased activity of dismutase and catalase as well as simultaneous increased MDA concentration were observed. In the lens on the 7th day the increased activity of dismutase was significant in relation to the results in the next time interval, whereas MDA concentration was significantly lower in all time intervals of the experiment in comparison with control group. In erythrocytes an increased activity of catalase was noticed on the 2nd and 14th day. CONCLUSIONS: Increased occurrence of active oxygen species in aqueous humor leads to insufficiency of the antioxidant system and intensification of peroxidation processes, which is reflected by increased MDA concentration. However, in the lens of this experimental model a slight stimulation of antioxidant system by a small number of free radicals is observed, which provokes a reaction of sweeping them away. Efficiency of lens antioxidant system is secured by weakening of peroxidation processes, which is expressed in minimal drop of MDA concentration.
Animals↗
Aqueous humor interleukin-6 levels in uveitis.
The level of Interleukin-6 (IL-6) in the aqueous humor of 24 patients with 2 types of uveitis was measured with a specific bioassay using the murine hybridoma cell line B9. Sixteen patients had Fuchs' heterochromic cyclitis (FHC) and 8 had toxoplasma uveitis (TU). Sixty-three percent of each of the FHC and TU groups had raised levels of IL-6 in their aqueous (mean: 543 and 19,228 units/ml respectively). Thirteen control aqueous samples, obtained at surgery for senile cataract, showed IL-6 levels of less than 10 units/ml. Serum obtained at the same time as each aqueous humor sample also showed IL-6 levels of less than 10 units/ml, indicating that the raised levels of IL-6 found in the aqueous of uveitis patients did not result from serum leakage, but from local production. This is the first report on intraocular IL-6 levels, and indicates that IL-6 may play a role as an inflammatory mediator in uveitis.
Adolescent↗
Ferning of aqueous humor in the pseudoexfoliation syndrome.
The authors report on the results obtained in the crystallization of the aqueous humor in 6 patients suffering from cataract with pseudoexfoliation syndrome. The principle characteristics of the aqueous in these cases are described and are compared with the features of aqueous humor in 20 cases of uncomplicated cataract. Tetragonal shaped masses of material with a distinct tendency to localization in the intersections of fern patterns were demonstrated in the crystallized aqueous from patients with pseudoexfoliation syndrome. These aggregates most probably correspond to exfoliation material.
Aged↗
The effect of dorzolamide on aqueous humor dynamics in normal human subjects during sleep.
OBJECTIVE: The purpose of the study was to measure the effect of the topical carbonic anhydrase inhibitor, 2% dorzolamide hydrochloride, on the rate of aqueous humor flow in sleeping humans. DESIGN: A randomized, double-masked, placebo-controlled study. PARTICIPANTS: Twenty-five normal human subjects. INTERVENTION: Topical instillation of 2% dorzolamide hydrochloride versus topical placebo. MAIN OUTCOME MEASURES: Rate of aqueous humor flow in sleeping humans and intraocular pressure immediately after awakening from sleep. RESULTS: The rate of flow in sleeping subjects at night (12 AM to 6 AM) was 1.28 +/- 0.30 microliters/min (mean +/- standard deviation; n = 25) in placebo-treated eyes, whereas the nighttime flow in dorzolamide-treated eyes was 1.17 +/- 0.38 microliters/min (P = < 0.001), resulting in a nighttime reduction of 9% (P = 0.032). In contrast, the daytime (8 AM to 4 PM) rate of flow in ambulatory subjects was 2.97 +/- 0.64 microliters/min in placebo-treated eyes and 2.60 +/- 0.63 microliters/min (P = 0.032) in dorzolamide-treated eyes, resulting in a daytime reduction of 13% (P = < 0.001). CONCLUSIONS: Topically administered dorzolamide hydrochloride is effective for reducing the rate of aqueous humor flow in normal human eyes during the day and at night during sleep. The efficacy of dorzolamide at these two times is approximately half that of systematically administered acetazolamide.
Administration, Topical↗
Amikacin levels in human aqueous humor.
Amikacin is one of the newer aminoglycoside antibiotics. The penetration of amikacin into the human primary aqueous humor after intramuscular application was investigated. Comparing our results with reports concerning the blood aqueous permeability of gentamicin and tobramycin we could not find any significantly better penetration of amikacin into the human aqueous humor after i.m. injection. The advantage of amikacin lies in its effectiveness against bacteria resistant to other aminoglycosides.
Aged↗
Outflow of aqueous humor following cyclodialysis or ciliochoroidal detachment in rabbit.
Cyclodialysis and ciliochoroidal detachment were performed in three eyes of three rabbits and in three eyes of another three rabbits, respectively. After aspiration of the aqueous humor, 0.1 ml of 10% sodium fluorescein was injected intracamerally, and the eyeball was enucleated between 30 minutes and one hour after injection and prepared for fluorescence microscopy. Sodium fluorescein concentrations in the supraciliary space were much greater in the group with cyclodialysis or ciliochoroidal detachment than in the normal control group. These results suggest that (1) in the eye with cyclodialysis, the aqueous humor may freely gain access to the supraciliary space through the cleft between the anterior chamber and the supraciliary space and then be removed rapidly and (2) in the eye with ciliochoroidal detachment, the aqueous humor may pass through the uveoscleral outflow pathway.
Animals↗
Presence of diadenosine polyphosphates in the aqueous humor: their effect on intraocular pressure.
Adenine dinucleotides are present in many biological systems and may serve as physiological regulators of processes such as neurotransmitter release, vascular tone or corneal hydration. The presence of diadenosine polyphosphates was investigated in New Zealand White rabbit aqueous humor. Diadenosine tetraphosphate (Ap4A) and diadenosine pentaphosphate (Ap5A) were identified and quantified in the aqueous humor with concentrations of 0.34 +/- 0.1 and 0.08 +/- 0.01 microM, respectively. The effects of topical corneal application of diadenosine pyrophosphate (Ap2A), diadenosine triphosphate (Ap3A), Ap4A, and Ap5A on intraocular pressure in rabbits were also studied. Ap2A, Ap3A, and Ap5A increased intraocular pressure with threshold doses of approximately 0.1 to 1.0 micro g. 10 microl(-1). Ap4A decreased intraocular pressure with an IC50 value of 0.12 micro g. 10 microl(-1) (or 0.13 nmol). Cross-desensitization studies suggested the activation of a P2X receptor for the hypotensive effect of Ap4A and a P2Y receptor in the case of Ap5A. The ATP receptor antagonists (all 100 micro g. 10 microl(-1)), pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid (PPADS), suramin, and reactive blue 2 (RB-2) alone had no effect on intraocular pressure but attenuated responses to diadenosine polyphosphates by approximately 80%. It is concluded that Ap2A, Ap3A, and Ap5A increase intraocular pressure, and Ap4A decreases intraocular pressure via mechanisms that involve P2 receptors, and that Ap4A present in aqueous humor may serve to regulate intraocular pressure. Furthermore, we suggest that topical application of Ap4A to the cornea has therapeutic potential for lowering intraocular pressure, a major risk factor for glaucoma.
Adenine Nucleotides↗
Electroconvulsive treatment evokes release of preprotachykinin-A mRNA into the cerebrospinal fluid and ocular aqueous humor of rabbits.
Following electroconvulsive treatment (ECT) of rabbits, preprotachykinin-A (PPT-A) mRNA was detected by Southern blot analysis of polymerase chain reaction (PCR)-amplified products in the cerebrospinal fluid (CSF) and aqueous humor of the eye. In contrast, no PPT-A mRNA could be detected in samples from untreated animals. In addition, several neuropeptides (substance P, neuropeptide Y, cholecystokinin, calcitonin gene-related peptide and pituitary adenylate cyclase activating peptide) were released into the CSF (and aqueous humor) following ECT. The results suggest that PPT-A mRNA was released together with neuropeptides into the CSF and aqueous humor in response to ECT. Indeed, previous studies have suggested that neurons can release neuropeptide mRNAs and that neurons are capable of taking up and expressing foreign mRNA. If neuropeptide mRNA can be taken up and utilized by another neuronal population, it might explain instances when neurons display 'phenotypic switch', i.e. the transient expression of novel neuropeptides.
Animals↗
The effect of latanoprost on aqueous humor PGF2alpha levels in glaucoma patients.
AIM: The purpose of this study is to evaluate the effect of the PGF2alpha isopropyl ester analogue, Latanoprost which is a new ocular hypotensive topical agent, on the aqueous humor PGF2alpha levels in open-angle glaucoma patients. METHODS: Patients diagnosed with either capsular or primary open-angle glaucoma and scheduled for trabeculectomy, were consecutively enrolled in the study. Group 1 represented the control group (n = 17) and Group 2 represented the Latanoprost treatment group (n = 9). All the topical drugs were stopped 10 days preoperatively and only systemic carbonic anhydrase inhibitors were continued if necessary. Group 2 patients received topical 0.005% Latanoprost once daily for 5-10 days preoperatively. During trabeculectomy operation, aqueous samples were taken through paracentesis from the patients. Aqueous humor levels of PGF2alpha and its metabolite 13,14-dihydro-15-keto-PGF2alpha were measured using enzyme-immunoassay. RESULTS: The mean PGF2alpha levels were 24.38 +/- 5.79 pg/ml in the control group and 10.99 +/- 4.11 pg/ml in the Latanoprost group, the difference of which was statistically significant (p < 0.05). In the Latanoprost group, there was a positive correlation between levels of PGF2alpha, and its metabolite (p < 0.05). CONCLUSION: Pretreatment with PGF2alpha isopropyl ester analogue, Latanoprost topically decreased PGF2alpha levels in the aqueous humor of glaucomatous eyes, probably due to its uveoscleral outflow increasing effect. The clinical importance and application of this result has to be determined.
Aged↗
Modulation of aqueous humor outflow facility by the Rho kinase-specific inhibitor Y-27632.
PURPOSE: The goal of this study was to investigate the role of Rho kinase in the modulation of aqueous humor outflow facility. Rho kinase, a critical downstream effector of Rho GTPase is recognized to control the formation of actin stress fibers, focal adhesions, and cellular contraction. METHODS: Expression of Rho GTPase, Rho kinase, and other downstream targets of Rho GTPase were determined in human trabecular meshwork (HTM) and Schlemm's canal (SC) primary cell cultures by Western blot analysis. The Rho kinase-specific inhibitor (Y-27632)-induced changes in actin stress fibers, focal adhesions, and protein phosphotyrosine status were evaluated by staining with rhodamine-phalloidin, anti-paxillin, and anti-phosphotyrosine antibodies, respectively. Myosin light-chain phosphorylation was determined by Western blot analysis. Y-27632-induced changes in SC cell monolayer permeability were quantitated using a colorimetric assay to evaluate horseradish peroxidase diffusion through SC cell monolayers grown in transwell chambers. Aqueous humor outflow facility was measured using enucleated porcine eyes and a constant-pressure perfusion system. RESULTS: Treatment of HTM and SC cells with Y-27632 (10 microM) led to significant but reversible changes in cell shape and decreases in actin stress fibers, focal adhesions, and protein phosphotyrosine staining. SC cell monolayer permeability increased (by 80%) in response to Y-27632 (10 microM) treatment, whereas myosin light-chain phosphorylation was decreased in both HTM and SC cells. Aqueous humor outflow facility increased (40%-80%) in enucleated porcine eyes perfused with Y-27632 (10-100 microM), and this effect was associated with widening of the extracellular spaces, particularly the optically empty area of the juxtacanalicular tissue (JCT). The integrity of inner wall of aqueous plexi, however, was observed to be intact. CONCLUSIONS: Based on the Rho kinase inhibitor-induced changes in myosin light-chain phosphorylation and actomyosin organization, it is reasonable to conclude that cellular relaxation and loss of cell-substratum adhesions in HTM and SC cells could result in either increased paracellular fluid flow across Schlemm's canal or altered flow pathway through the JCT, thereby lowering resistance to outflow. This study also suggests Rho kinase as a potential therapeutic target for the development of drugs to modulate intraocular pressure in glaucoma patients.
Actins↗
Effect of gatifloxacin ophthalmic solution 0.3% on human corneal endothelial cell density and aqueous humor gatifloxacin concentration.
PURPOSE: To evaluate the effect of gatifloxacin ophthalmic solution 0.3% (Zymar, Allergan, Inc., Irvine, CA, USA) on corneal endothelial cell density and morphology and to measure gatifloxacin penetration into aqueous humor. METHODS: This was a single-center, open-label clinical study. Ten patients undergoing standard cataract surgery and 20 nonsurgical subjects instilled gatifloxacin 0.3% four times per day for 2 days, then every 10 min for 1 hr on the third day (the surgery day for the cataract patients). Corneal endothelial cells were counted using noncontact specular microscopy. Anterior chamber fluid was withdrawn from the surgical patients, and the gatifloxacin concentration was quantified by high-pressure liquid chromatography. RESULTS: Baseline endothelial cell counts (mean +/- SD) were 2400 +/- 442 in the surgical group and 2520 +/- 212 in the nonsurgical group. The mean differences from baseline 1 hr after the last dose of gatifloxacin 0.3% were -51 +/- 213 (p = 0.23) in the surgical group and -7 +/- 150 (p = 0.42) in the nonsurgical group. In the nonsurgical group, the mean difference from baseline 3 weeks after the last dose was 18 +/- 147 (p = 0.71). The mean concentration (+/- SD) of gatifloxacin in aqueous humor was 1.26 +/- 0.55 microg/ml. CONCLUSIONS: A preoperative, prophylactic course of gatifloxacin 0.3% ophthalmic solution did not significantly affect endothelial cell density or morphology, while meaningful drug concentration was achieved in the aqueous humor.
Administration, Topical↗