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At least 487 records · Page 27Linked to original sources
PubMed2005

Expression of dominant negative Rho-binding domain of Rho-kinase in organ cultured human eye anterior segments increases aqueous humor outflow.

PURPOSE: Based on pharmacological inhibition of activity, a role has been proposed for Rho-kinase in the modulation of aqueous outflow and intraocular pressure (IOP). This study employed a molecular approach to specifically address the role of Rho-kinase in the modulation of aqueous humor outflow. METHODS: Adenoviral vectors expressing green fluorescent protein alone (Ad-GFP) or the dominant negative Rho-binding domain of Rho-kinase and GFP (Ad-DNRK-GFP) were utilized in these experiments. Human and porcine primary trabecular meshwork (TM) cells were infected with 30 MOI (multiplicity of infection) of Ad-GFP alone or with Ad-DNRK-GFP. Changes in cell shape, actomyosin cytoskeletal integrity, and the status of myosin light chain (MLC) phosphorylation were evaluated. The aqueous outflow facility was determined in organ cultured anterior segments of human cadaver eyes infected with 10(7) pfu adenoviral vectors (Ad-GFP or Ad-DNRK-GFP) using a constant flow perfusion system. RESULTS: Expression of DNRK resulted in changes in cell shape (cell rounding, cell-cell detachment) and decreased actin stress fiber and focal adhesion staining in TM cells. These cellular changes were associated with substantially reduced myosin light chain phosphorylation. Additionally, organ cultured human eye anterior segments infected with Ad-DNRK-GFP exhibited a significant increase in the outflow facility (80%, n=9) compared to control anterior segments infected with Ad-GFP (5%). CONCLUSIONS: This study demonstrated that specific inhibition of Rho-kinase activity in trabecular meshwork cells led to alterations in cell shape and presumed contractile properties, and we hypothesize that these morphological and contractile events underlie the observed effects of dominant negative Rho-kinase on the aqueous humor outflow facility. These data provide molecular evidence for the hypothesis of Rho-kinase being a potential cellular target involved in the regulation of aqueous humor outflow resistance, with implications for novel glaucoma therapy.

Actins↗
PubMedDate not supplied

[Morphometric analysis of the structure of tear and aqueous humor in senile cataract].

The parameters of the wedge dehydrated samples of aqueous humor and tear taken from patients with senile cataract were compared by a morphometric assay. Computer-aided processing of the images of the test biological fluids was made on a Morphotest-1 hardware-software complex. The study has provided evidence for the uniformity of distribution of major structural components in the dehydrated samples of tear and aqueous humor in each specific examinee. This fact opens up possibilities for studying the signs of different intraocular pathological conditions from the morphological pattern of tear.

Aged↗
PubMed1996

Increased matrix metalloproteinases in the aqueous humor of patients and experimental animals with uveitis.

PURPOSE: Matrix metalloproteinases (MMPs) play a major role in connective tissue remodelling, wound healing and embryogenesis. They have also been implicated in pathological tissue degradation in diseases such as rheumatoid arthritis (RA), osteoarthritis (OA), and tumor invasion. The aim of this study was to define the potential role of MMPs in the inflammatory process of uveitis by identifying these proteases in the aqueous humor (AH) of patients with uveitis and in rabbits with endotoxin-induced uveitis (EIU). METHODS: Aqueous humor samples from 6 patients with uveitis and 5 control patients who had undergone elective cataract surgery were examined. The profile of MMPs in the AH of experimentally-induced acute anterior uveitis in rabbits was also assessed. Western blot analysis and SDS-PAGE substrate zymography were used to detect metalloenzymes and their natural inhibitor, tissue inhibitor of metalloproteinase (TIMP-1) in aqueous samples. RESULTS: Aqueous humor from all patients contained interstitial collagenase (MMP-1), stromelysin (MMP-3), gelatinase B (MMP-9) and TIMP-1. Although the amount of MMPs varied considerably, TIMP-1 levels remained unchanged in the aqueous of uveitis patients. Using substrate gel zymography, we were able to reveal several gelatinolytic bands, including one major band at approximately 92-kDa whose activity differed between uveitis and cataract AH. The gelatinase activity found in human AH samples was shown to be inhibited by 10 mM EDTA and activated in vitro by APMA, indicating that these enzymes were indeed of the metalloproteinase class. Aqueous humor samples from the rabbit EIU model revealed a 100-kDa molecular weight species likely to correspond to gelatinase B. This gelatinolytic activity was maximal at 6 hours after the lipopolysaccharide (LPS) injection, declined at 12 and 24 hours post LPS, and was absent at later time points. The induction of gelatinase activity in rabbit AH preceded the increase in cell number during the inflammatory process in the anterior chamber. CONCLUSIONS: Metalloproteinases found in normal human AH may participate in physiological turnover of extracellular matrix in the eye. Elevated levels of MMPs were found in the AH of patients with uveal inflammation and animals with LPS-induced uveitis, where they are likely to be critical to tissue destructive and repair processes. It is likely that pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 alpha (IL-1 alpha), which are known modulators of MMPs, induce their secretion in acute anterior uveitis.

Acute Disease↗
PubMed1994

Protein quantification and electrophoresis in aqueous humor of pseudoexfoliation eyes.

PURPOSE: Pseudoexfoliation (PSX) eyes frequently show clinical signs of blood-aqueous barrier impairment. To analyze these alterations, the authors examined aqueous humor of human eyes with and without PSX. METHODS: After aqueous humor samples had been obtained during cataract or filtering glaucoma surgery, a modified Pierce-bicin choninic acid assay was used to quantify total aqueous protein concentration in 27 PSX eyes and 37 eyes without clinical signs of PSX (12 cataract eyes and 25 eyes with primary open-angle glaucoma). In addition, aqueous protein composition was analyzed by sodium dodecylsulfate polyacrylamide gel electrophoresis, silver staining, and laser densitometry in 27 PSX eyes and 59 eyes without PSX. RESULTS: Aqueous protein concentration was significantly higher in PSX (mean 0.42 +/- 0.16 mg/ml) than in normal cataract eyes (0.22 +/- 0.08 mg/ml, P < 0.0001) and in eyes with open-angle glaucoma (0.26 +/- 0.09 mg/ml, P < 0.0001, Wilcoxon-Mann-Whitney test). Electrophoresis revealed a characteristic increase of a 12.5-kDa band in 15 of 27 PSX eyes but in only 1 of 59 eyes without PSX (P < 0.00001, chi-square test). CONCLUSIONS: These results substantiate increased aqueous protein concentration and aqueous barrier impairment in PSX. The additional finding of an increased 12.5-kDa band in 56% of PSX eyes may be related to the pathogenesis of PSX in the anterior ocular segment.

Aged↗
PubMed2005

Development and validation of a new reversed-phase ion pairing liquid chromatographic method with fluorescence detection for penciclovir analysis in plasma and aqueous humor.

A simple, sensitive and reliable HPLC ion-pairing method with fluorescence detection, was developed for penciclovir determination in plasma and aqueous humor, with a Zorbax SB-aq C18 (100 mmx2.1 mm) column. Plasma samples were treated by solid-phase extraction with Oasis MCX (30 mg) cartridges. Ganciclovir, an antiviral drug structurally related to penciclovir, was used as internal standard (I.S.). Aqueous humor samples were directly injected into the chromatographic system. Separation was performed by a gradient elution with a mobile phase consisting of a mixture of acetonitrile and phosphate buffer 50mM containing 5mM of sodium octanesulfonate, pH 2.0, at a flow rate of 0.3 ml/min. The method was validated and showed good performances in terms of linearity, sensitivity, precision and trueness. Quantification limit was obtained at 0.05 microg/ml for aqueous humor and at 0.1 microg/ml for plasma. Finally, the proposed analytical method was used to measure penciclovir in clinical samples for a pharmacokinetic study, after oral administration of famciclovir.

Acyclovir↗
PubMed2000

[Direct measurement of nitric oxide levels in aqueous humor with selective iso-NO electrode under physiologic conditions and after phacoemulsification and artificial acrylic lens implantation in experiments on rabbits].

PURPOSE: Using a direct method, with selective and nitric oxide sensitive electrode Iso-NO, we estimated the level of the Nitric Oxide (NO) in the aqueous humor of the rabbit's eye after phacoemulsification and acrylic foldable lens implantation. We also analysed the NO level during early postoperative days between the 1st and the 5th postoperative day. The current methods of the NO level estimations are also considered. MATERIAL AND METHODS: We examined 30 gray rabbits (weighing 3.0-3.5 kg). Just before surgery, samples of aqueous humor were aspirated. Lens was extracted with phacoemulsification technique. In 15 eyes acrylic foldable IOL was implanted and 15 eyes were left aphacic. The aqueous samples were collected 1, 3, 5 days after surgery. Nitric oxide in each sample was determined with direct, selective nitric oxide sensitive electrode Iso-NO. Because of changing values of the NO concentration and its characteristic course, we expressed the concentration of NO in aqueous humor using field-under-curve method to compare it with control group. The results of our examination are presented in the absolute values. RESULTS: During physiological conditions the mean value of the field under curve of the NO concentration was estimated as 4987.29 +/- 895.89. After phacoemulsification with or without artificial lens implantation the level of the NO was higher as compared to the control group. After phacoemulsification and acrylic foldable lens implantation the highest level of NO was estimated on the 1st postoperative day as 6917.10 +/- 1199.72. During the examinations, the field under curve of NO concentration was estimated as 6246.63 +/- 327.02 and 5172.28 +/- 552.67 (on the 3rd and 5th days respectively). Only on the 1st and the 3rd postoperative day, the value of the field under curve of NO was significantly higher as compared with the control group. In contrast, after phacoemulsification without lens implantation the highest value of NO field under curve, was estimated on the 3rd postoperative days as 5801.44 +/- 344.45. During the examinations, the field under curve of NO concentration was estimated as 5115.30 +/- 796.11 and 4837.12 +/- 205.87 (on the 1st and the 5th days, respectively). Moreover, it was the only one day of examination with significantly higher value of NO field under curve as compared with the control. CONCLUSION: We came to conclusion that the level of nitric oxide in aqueous humor after phacoemulsification with or without artificial lens implantation is higher than in control group. The highest value of the field under curve was estimated on the 1st postoperative day after phacoemulsification and acrylic foldable lens implantation and on the 3rd postoperative day after phacoemulsification without lens implantation.

Animals↗
PubMed1985

Azlocillin levels in human tears and aqueous humor.

We administered 4 g of azlocillin sodium intravenously to 24 patients scheduled to undergo elective intraocular surgery and collected specimens of serum, tears, and aqueous humor from zero to six hours after infusion for assay by high-pressure liquid chromatography. We found that azlocillin is distributed into tears and penetrates into the aqueous humor of human volunteers with noninflamed eyes after a single intravenous dose. Levels of 4.17 micrograms/ml and 4.44 micrograms/ml were achieved in tears and aqueous humor, respectively.

Aqueous Humor↗
PubMed1994

The effect of oral dexamethasone on the circadian rhythm of aqueous humor flow in humans.

PURPOSE: To determine if the circadian rhythm of plasma corticosteroid activity is necessary for the circadian rhythm of aqueous humor flow to occur in humans. METHODS: Twenty normal volunteers were recruited for this randomized, double-masked, placebo-controlled study. Oral dexamethasone was given at a dose of 0.5 mg every 6 hours; this is equivalent to more than two times the normal 24-hour endogenous adrenal corticosteroid production. This dosage schedule will maintain a relatively constant level of corticosteroid action throughout a 24-hour period. Topical fluorescein and a scanning fluorophotometer were used to measure the rate of aqueous humor flow. Subjects were studied on two separate days. On one study day, the subject took 0.5 mg of dexamethasone every 6 hours; on the other study day, the same subject took a placebo every 6 hours. RESULTS: During the morning, aqueous flow was 4.06 +/- 0.70 microliters/min (mean +/- SD) in subjects taking dexamethasone and 3.82 +/- 0.85 in subjects taking a placebo. This 6% higher dexamethasone flow was not significant (P = 0.10). During the afternoon, aqueous flow was 3.83 +/- 0.78 in subjects taking dexamethasone and 3.52 +/- 0.77 in subjects taking a placebo. This 9% higher dexamethasone flow was statistically significant (P = 0.02). The nighttime aqueous flow was 1.38 +/- 0.45 in subjects taking dexamethasone and 1.43 +/- 0.34 in subjects taking the placebo. There was not a significant difference between placebo and dexamethasone during the night (P = 0.40). On each day, intraocular pressure was measured at 8:00 AM, 4:00 PM, and 6:00 AM. When comparing dexamethasone to placebo, no significant difference was observed in any of the intraocular pressures. CONCLUSIONS: The study is interpreted as showing that the reduction of aqueous humor flow during sleep can occur in the absence of a comparable fall in plasma corticosteroid pathway.

Administration, Oral↗
PubMed1991

Relationship in humans between ascorbic acid consumption and levels of total and reduced ascorbic acid in lens, aqueous humor, and plasma.

The relationships between plasma, aqueous humor and lens ascorbic acid levels are examined in 131 samples from 127 patients. Mean ascorbate intake for nonsupplemented individuals was 148 mg/day or over two times the recommended daily allowance. A subset of 44 patients participated in a trial to assess the impact of vitamin C supplementation of 2 grams per day on aqueous and lens ascorbic acid levels. Such supplementation significantly increased both total and reduced ascorbic acid levels in plasma and aqueous and total ascorbic acid in the lens. Correlation coefficients relating total and reduced ascorbic acid levels in the three tissues ranged from 0.42 to 0.19 (p less than 0.05 for all correlation coefficients). Over 60% of the ascorbate was present in the reduced form in plasma and aqueous, and about 50% of the lens ascorbate was in the reduced form.

Adult↗
PubMed2006

Concordance of aqueous humor flow in the morning and at night in normal humans.

PURPOSE: To test the hypothesis that an individual shows concordance of aqueous humor flow in the morning and at night in a prospective inpatient fluorophotometry study in healthy subjects. METHODS: Flow was measured in each eye every hour between 8 AM and noon and every 2 hours between midnight and 6 AM. Morning and nighttime flows were analyzed for differences between eyes and for differences between these two time points. Concordance of individual morning and nighttime flows were studied by categorization into low, medium, or high tertiles, dot plot, and ordinary least-squares regression (OLS) scatter plot. RESULTS: In 28 subjects, the flow was similar between eyes within a subject with healthy eyes. In the one eye examined in each subject, the average flow was 3.12 +/- 1.09 muL/min in the morning, which decreased significantly to 1.59 +/- 0.58 muL/min at night. During each time period, the individual flow data were normally distributed. Concordance of an individual's morning and nighttime flows was 68%. A scatter plot of morning versus nighttime flows also supported concordance with an OLS regression fit of r(2) = 0.45. CONCLUSIONS: The results provide evidence that aqueous humor flow is similar between eyes, that flow variation shows a normal distribution, and that individuals show a concordance of flow in the morning and at night. These observations support the posit that aqueous humor flow, which is a factor that contributes to the important clinical risk factor of IOP variation, is amenable to study as a quantitative trait.

Adolescent↗
PubMed1983

The arterially perfused enucleated rabbit eye as a model for studying aqueous humor formation.

The rate of turnover of aqueous humor (Kout), as measured by the decay of radioactive inulin from the anterior chamber of the enucleated eye, was similar to the rate of loss of 125I-RISA (radioiodinated serum albumin) from the eye of a living rabbit. Arterial perfusion with 125I-RISA or rabbit serum showed that the permeability characteristics of the blood-aqueous barrier to protein molecules are unaffected in the enucleated eye. The viability of the enucleated eye for secretion of ascorbic acid was also examined, but the results were inconclusive.

Animals↗
PubMed1988

Procoagulant effect of aqueous humor on in vitro clotting of blood and plasma.

Fresh and previously frozen aqueous humor was found to shorten the recalcification time of both canine citrated blood and human citrated plasma. This state of accelerated coagulation was dose related and preliminary studies indicate that aqueous humor acts as a procoagulant rather than a thromboplastin-like substance.

Animals↗
PubMed1975

Prostaglandin-like activity in the aqueous humor following alkali burns.

Following application of 20 mul of 2 N sodium hydroxide to the rabbit cornea, the prostaglandin-like activity in the aqueous humor increased from undetectable levels to around 30 ng, per milliliter, a level which was sustained for up to 24 hours. This increase correlated with the previously reported sustained elevation of intraocular pressure following a 20 mul alkali burn. Pretreatment with aspirin or indomethacin virtually abolished the increase in intraocular pressure and elevation of prostaglandin-like activity in the aqueous humor following a 20 mul burn. Marked ocular hypotension following 50 mul and 100 mul sodium hydroxide burns correlated with very low prostaglandin-like activity in the aqueous humor. The low prostaglandin-like activity probably resulted from alkaline hydrolysis of aqueous prostaglandins and massive cellular death in iris and ciliary body tissues.

Alkalies↗
PubMed1982

The effect of vitamin A and cortisone on ascorbic acid content in the aqueous humor.

Thus, it can be concluded from our observations that the effect of cortisone drops in reducing the concentration of ascorbic acid in the aqueous humor can be neutralized by simultaneous administration of vitamin A drops. This observation has an important clinical bearing, as ophthalmologists have hesitated to use cortisone locally for a long time for fear that it may either precipitate glaucoma or cataract (most probably because of the subsequent lowering of ascorbic acid concentration in the aqueous humor and lens). Our finding that with the administration of vitamin A drops along with cortisone drops there is no significant lowering of the ascorbic acid level in the aqueous humor indicates that one can use cortisone drops without being afraid of precipitating glaucoma or cataract.

Animals↗
PubMed1997

Penetration of oral cefuroxime axetil into the human aqueous humor.

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.

Administration, Oral↗
PubMed1988

Effect of cold air on aqueous humor dynamics in humans.

Several parameters of aqueous humor dynamics were measured in 11 human subjects before and after exposure of one eye to a continuous stream of cold air. In the treated eye, I.O.P. was found to decrease significantly from a mean +/- SD pre-treatment value of 14.1 +/- 2.3 mmHg to a post-treatment value of 12.6 +/- 2.6 mmHg. Episcleral venous pressure was found to decrease significantly from a pre-treatment value of 6.2 +/- 1.3 mm Hg. No significant changes were found in aqueous flow or total outflow facility, indicating that cold air exposure decreased I.O.P. by causing a decrease in episcleral venous pressure.

Air↗
PubMed2004

The number of CD8+ T cells and NKT cells increases in the aqueous humor of patients with Behçet's uveitis.

To determine whether there are differences in the immunopathogenesis of different endogenous uveitis syndromes, the phenotypic characteristics of immune cells were analysed among patients with endogenous uveitis. The aetiology of the uveitis included idiopathic recurrent acute anterior uveitis (18 patients), idiopathic intermediate uveitis (13 patients), Behçet's uveitis (17 patients), Vogt-Koyanagi-Harada syndrome (7 patients), and so on. Flow cytometric analysis was performed using immune cells of the aqueous humor and the peripheral blood during the active phase of intraocular inflammation, and monoclonal antibodies to CD3, CD4, CD8, CD14, CD19, CD56, TCR gammadelta, pan TCR alphabeta and Valpha24. CD8+ T cells were predominant in the aqueous humor of the patients with Behçet's uveitis, whereas CD4+ T cells were mainly found in the aqueous humor of patients other than those with Behçet's uveitis. The number of NKT (CD3+CD56+) cells was significantly higher both in the aqueous humor and the peripheral blood of the patients with Behçet's uveitis compared with the other groups (P < 0.05). CD8+CD56+ cells were the predominant subtype of the increased NKT cells in patients with Behçet's uveitis. In addition, intraocular infiltration of CD14+ cells significantly differed among the uveitis patients (P < 0.05). These results suggest that the immunopathogenesis of endogenous uveitis can vary between syndromes, and that CD8+CD56+ NKT cells may play an important role in the immunopathogenesis of Behçet's uveitis.

Adolescent↗