PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Aqueous Humor”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 955 records · Page 53Linked to original sources
PubMed1979

Immediate changes in protein-concentration in aqueous humor induced by intracapsular lens extraction in human eyes.

In 71 patients that underwent intracapsular extraction of the cataract it was possible to collect aqueous humor (a.h.) in sufficient quantities at the beginning and at the end of the operation. Using radial immunodiffusion albumin, IgG and alpha-1-antitrypsin were measured in the samples. In secondary a.h. huge variations in the concentrations were apparent. The primary permeability of the blood-aqueous barrier and the time between sampling had no influence on the relative increase of the proteins. No statistically significant difference was found between normotensives and hypertensives and patients with or without myopia of higher degree (over 6 diopters). The relative increase of proteins according to their difference in molecular weight followed the same pattern as described for anterior uveitis. In patients for whom an enzymatic zonulolysis with trypsin was used for the extraction, the relative increase of IgG was significantly smaller than in those that did not receive this treatment (P less than 0.005). The possible sources contributing to the formation of secondary a.h. are discussed.

Aged↗
PubMed1998

Effects of topical nipradilol, a beta-blocking agent with alpha-blocking and nitroglycerin-like activities, on aqueous humor dynamics and fundus circulation.

PURPOSE: To study the effects of nipradilol, a nonselective beta-blocker with alpha 1-blocking activity and nitroglycerin-like activity, on aqueous humor dynamics and optic nerve head (ONH) circulation in albino rabbits. METHODS: Experiments were carried out during the dark phase, in conscious rabbits conditioned to a schedule of alternating 12-hour periods of light and dark. The blood-aqueous barrier permeability and the aqueous flow rate were determined fluorophotometrically. The effect on outflow to general blood circulation and uveoscleral outflow were determined by using the fluorophotometric Diamox technique, and the effect on the uveoscleral outflow was further assessed by using the anterior chamber perfusion method. The ONH circulation was estimated by using the laser speckle method. RESULTS: Unilateral topical administration of 0.25% nipradilol solution lowered intraocular pressure (IOP) with relatively weak contralateral effects in a dose-dependent manner with a maximum reduction of 6 mm Hg and an effect duration of 6 hours. Twice-daily instillation for 14 days showed no attenuation of the effects. Single instillation of 0.25% nipradilol showed no significant effect on blood-aqueous barrier permeability and decreased aqueous flow rate in the treated eye (17%; P < 0.01) and in the contralateral eye (9%, P < 0.05). Nipradilol produced no significant effect on outflow facility to general blood circulation, whereas it substantially increased uveoscleral outflow. Twice-daily 0.25% nipradilol instillation increased ONH tissue blood velocity by 13% (P < 0.01), which was probably attributable to locally penetrating drug. CONCLUSIONS: Because of its ability to lower IOP and to increase uveoscleral outflow and optic nerve head circulation in rabbits, further studies are warranted to determine whether nipradilol has potential as an antiglaucoma agent in humans.

Administration, Topical↗
PubMed1993

A model to predict aqueous humor and plasma pharmacokinetics of ocularly applied drugs.

PURPOSE: To develop methods for constructing a pharmacokinetic model to predict the time course of aqueous humor and plasma drug concentrations after topical dosage in rabbits using the simulation program iThink (formerly STELLA; High Performance Systems, Lyme, NH). METHOD: The model was constructed in experimentally verifiable segments using previously published data on intravenous, nasal, and ocular dosage, and was used to describe the influence of prolonging precorneal retention and varying drug release rate on the ratio of drug absorbed locally to drug absorbed systemically in rabbits. RESULTS: The model developed is comprehensive; it includes precorneal kinetics, nasal absorption kinetics, and plasma kinetics. CONCLUSIONS: Such a model may be useful in designing drug delivery strategies to improve the safety of topical eye medications through minimization of systemic absorption and maximization of drug delivery to ocular tissues.

Absorption↗
PubMed1975

[Effect of amitriptyline and nortriptyline on the intracular pressure and aqueous humor dynamics in rabbits (author's transl)].

Both amitriptyline and nortriptyline applied conjunctivally produced pupil size enlargement, intraocular pressure decrease and a fall in aqueous humor formation. Phenoxybenzamine and superior cervical sympathetic ganglionectomy prevented the amitriptyline or nortriptyline inducing intraocular pressure changes. Either systemic administered or conjunctivally applied amitriptyline or nortriptyline, potentiated the effects on the pupil and intraocular pressure of exogenously norepinephrine.

Amitriptyline↗
PubMed2002

Association of herpesviruses in the aqueous humor of patients with serpiginous choroiditis: a polymerase chain reaction-based study.

PURPOSE: To determine the presence of herpesvirus DNA in the aqueous humor (AH) of patients with serpiginous choroiditis using polymerase chain reaction (PCR). METHODS: AH from nine patients previously diagnosed with serpiginous choroiditis were investigated for herpes simplex virus (HSV), varicella zoster virus (VZV), and cytomegalovirus (CMV) by conventional virological methods and PCR. The PCR-positive DNA was gel-purified, extracted, and sequenced using a dye-based Applied Biosystems procedure. The sequences were processed through the National Cancer Institute's BLAST inquiry for species identification. RESULTS: Culture and cytological examination of AH from all nine patients were negative for HSV, VZV, and CMV. Five were positive for VZV, one was positive for HSV, and three were wholly negative using PCR. Subsequent DNA sequencing of the positive samples authenticated the presence of VZV and HSV DNA in the respective patients. CONCLUSION: VZV and HSV DNA were detected in a subset of patients with serpiginous choroiditis, suggesting that these viruses may function in the pathogenesis of this disease.

Adult↗
PubMed1996

Effect of dapiprazole, an alpha-adrenergic blocking agent, on aqueous humor dynamics in pigmentary glaucoma.

PURPOSE: In this investigation the authors studied the effect of dapiprazole, an alpha-adrenergic blocking agent, on aqueous humor dynamics in patients affected with pigmentary glaucoma. METHODS: Dapiprazole 0.5% eye drops were administered 3 times daily as adjunctive therapy to 16 pigmentary glaucoma patients in addition to timolol 0.5% eye drops twice daily. Computerized tonography was performed before and 3, 12 and 36 months after dapiprazole treatment. Sixteen sex- and age-matched pigmentary glaucoma patients treated with timolol 0.5% eye drops alone were used as a control group. RESULTS: After 36 months of follow-up, the dapiprazole-treated group showed a significant increase in total outflow facility (C, from 0.17 +/- 0.04 to 0.22 +/- 0.07 ml min-1 mm Hg-1; p = 0.010, paired t test) and Po/C ratio (Q) significantly decreased from 113.39 +/- 31.02 to 89.22 +/- 51.66 (p = 0.036, paired t test). CONCLUSIONS: Our results show that the introduction of dapiprazole in the therapy of pigmentary glaucoma may be useful in the long-term management of these patients. Its mechanism of action is likely to be due to iridoplegia; in fact, a decrease in the shedding of pigment occurs, with time, the outflow facility increases and the pigment clearance from the trabecular meshwork is enhanced.

Administration, Topical↗
PubMed2005

Putative aqueous humor misdirection syndrome as a cause of glaucoma in cats: 32 cases (1997-2003).

OBJECTIVE: To characterize the clinical and morphologic aspects of aqueous humor misdirection syndrome (AHMS) in cats and provide a hypothesis regarding its pathogenesis on the basis of detailed analysis of affected cats. DESIGN: Retrospective study. ANIMALS: 32 cats (40 eyes). PROCEDURE: Medical records of cats in which AHMS was diagnosed from July 1997 to August 2003 were reviewed. In certain cats, results of additional diagnostic testing were also obtained, including A-scan, B-scan, and high-resolution ultrasonography; streak retinoscopy; video keratometry; and infrared neutralizing videoretinoscopy as well as results of analysis of flash-frozen sections and histologic examination of enucleated globes. RESULTS: Cats had a uniformly shallow anterior chamber, intact lens zonules, and a narrowed approach to an open iridocorneal angle. Mean age of affected cats was 11.7 years (range, 4 to 16 years), and female cats were significantly more often affected than male cats. Clinical signs included mydriasis, decreased pupillary light reflex, decreased menace response, and blindness. Glaucomatous changes to the optic nerve, incipient cataracts, and eventual blindness were seen. Intraocular pressure was > or = 20 mm Hg (range, 12 to 58 mm Hg) in 32 of 40 eyes. Ultrasonography and histologic examination revealed a thickened anterior vitreal face interposed between the lens and ciliary body, partial ciliary cleft collapse, and cavitated vitreal regions. Various treatment modalities were used. CONCLUSIONS AND CLINICAL RELEVANCE: AHMS affects older cats, especially females, and may result in glaucoma, vision loss, and signs of ocular pain. Topical administration of carbonic anhydrase inhibitors decreased intraocular pressure.

Age Factors↗
PubMed1992

Continuous flow contact lens delivery of gentamicin to rabbit cornea and aqueous humor.

The Morgan Therapeutic Lens (MTL) was investigated as a continuous corneal perfusion system in New Zealand white rabbits. Gentamicin concentration in the cornea and aqueous humor delivered by the MTL was compared to gentamicin drops (13.6 mg/ml) administered every 15 or 30 minutes. Gentamicin (1 mg/ml) or 5 mg/ml was perfused at 10 ml/hr for up to 4.0 hours. At each time interval of 0.5, 1, 2 and 4 hours, homogenized corneas and aqueous humour were assayed for gentamicin concentrations. The highest aqueous humour gentamicin concentrations of 57.99 +/- 12.86 micrograms/ml were significantly higher with the MTL and 5 mg/ml of gentamicin compared with the MTL and 1 mg/ml of gentamicin or than drops applied every 30 minutes, but not significantly different than drops every 15 minutes. Highest corneal concentrations of gentamicin of 496.04 +/- 101.16 micrograms/gm cornea were significantly higher with MTL and 5 mg/ml of gentamicin compared with the MTL and 1 mg/ml gentamicin or than drops applied every 30 minutes, but not significantly different than drops every 15 minutes. All mean gentamicin concentrations attained via the MTL exceeded the mean inhibitory concentration for most sensitive bacterial species. The MTL is a reliable drug delivery system with distinct advantages, and may be a useful therapeutic modality in the ocular delivery of gentamicin and other drugs.

Animals↗
PubMed1994

[Tyndallometry with the laser flare cell meter and biochemical protein determination in the aqueous humor of eyes with pseudoexfoliation syndrome].

UNLABELLED: Slit-lamp examination and flare measurement in eyes with pseudoexfoliation (PSX) syndrome frequently reveal signs of impairment of the blood-aqueous barrier. We studied both aqueous flare and aqueous protein concentration in PSX eyes to verify and quantify these alterations. PATIENTS: Aqueous flare was measured using the Laser Flare-Cell Meter Kowa FC-1000 in 158 normal control eyes (age 56.0 +/- 12.0 years), in 60 PSX eyes (age 72.5 +/- 9.4 years), and in 84 eyes with primary chronic open-angle glaucoma (PCOAG) (age 56.3 +/- 12.4 years). Total aqueous protein concentration was determined biochemically in 12 "normal" control eyes with senile cataracts (age 57.6 +/- 20.4 years), in 27 PSX eyes (age 72.6 +/- 9.1 years), and in 25 PCOAG eyes (age 63.3 +/- 13.5 years). After the primary aqueous humor was aspirated during cataract extraction or trabeculectomy, a modified BCA-Peirce method was employed. RESULTS: In PSX eyes, both aqueous flare (12.3 +/- 8.2 photon counts/ms) and aqueous protein concentration (0.42 +/- 0.16 mg/ml total protein) were significantly increased in comparison with normal control eyes (4.3 +/- 1.1 photon counts/ms and 0.22 +/- 0.08 mg/ml) and with PCOAG eyes (4.7 +/- 1.6 photon counts/ms and 0.26 +/- 0.09 mg/ml) (P < 0.0001). Differences between normal control eyes and PCOAG eyes were not significant (P > 0.05). There was a high correlation between aqueous flare measurements and aqueous protein concentration in eyes with PSX (y = 0.27x + 0.29, r = 0.65, P = 0.0006, n = 24). CONCLUSIONS: Our results indicate that impairment of the blood-aqueous barrier with an increase in aqueous protein concentration is a feature of PSX and may be quantified both by flare measurement and biochemical protein determination. These alterations should be considered in the pharmacological and surgical treatment of PSX eyes.

Adult↗
PubMed1994

Penetration of cyclosporin A into the rabbit cornea and aqueous humor after topical drop and collagen shield administration.

We used commercially available 12-hour collagen shields to deliver cyclosporin A (CsA) to the cornea and aqueous humor in rabbit eyes. Six New Zealand white rabbits were divided into three groups. The first group (four eyes) received 6 mg of CsA in castor oil and the second group (four eyes) received 6 mg of CsA in olive oil applied as topical drops to rabbit eyes within 12 hours. In the third group (four eyes) 12-hour collagen shields soaked in 6 mg CsA in olive oil were applied to rabbit eyes. The amount of CsA in corneal and aqueous samples from eyes treated with CsA castor oil and CsA olive oil were compared with each other and with collagen shield treated eyes. CsA concentrations were measured by radioimmunoassay. After the total dose of 6 mg CsA, percentage penetration was measured as follows: CsA castor oil--0.51% in aqueous and 20.75% in cornea; CsA olive oil--0.17% in aqueous and 11.13% in cornea; and with collagen shields--0.44% in aqueous and 11.84% in cornea. These results show that the CsA levels of castor oil drops were higher than those obtained with olive oil drops. In eyes with collagen shields, CsA levels were higher than olive oil drops but nearly equal to the castor oil drops. Collagen shields may be useful as an ocular delivery system for CsA.

Administration, Topical↗
PubMed1984

Cefonicid concentrations in human aqueous humor.

One-gram doses of cefonicid sodium were given intravenously to patients prior to cataract surgery. Although serum levels were high, cefonicid levels in aqueous humor were low: mean peak concentrations of 0.25 and 0.27 mg/L were observed two and four hours after administration, respectively. The unusually high protein binding of cefonicid may explain these observations. The observed concentrations were not above the minimum inhibitory concentrations of cefonicid for those pathogens commonly involved in bacterial endophthalmitis.

Aqueous Humor↗
PubMed1999

Interleukin 6 and its soluble receptor are elevated in aqueous humor of patients with uveitis.

PURPOSE: To determine the levels of interleukin 6 (IL-6) and its soluble receptor (sIL-6R) in the aqueous humor (AH) of patients with different uveitis entities. PATIENTS AND METHODS: AH and serum samples were collected from 35 patients (39 eyes) who underwent surgery for uveitis complications and from 10 controls (senile cataract). In the studied group, seven patients had HLA-B27(+) anterior uveitis, two had Fuchs' heterochromic iridocyclitis, 12 had chronic anterior uveitis of unknown etiology, and in the remaining 14 the causative agent was exogenous. The cytokine and receptor levels were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: In controls, the median IL-6 level in AH was higher than that in corresponding sera (40.4 pg/ml and 5.2 pg/ml, respectively). In contrast, sIL-6R showed an inverse relation: there were less sIL-6R in control AH than in control sera (378.9 pg/ml and 52749.0 pg/ml, respectively). The same qualitative relationship was observed in patients with uveitis. Quantitatively, in comparison to controls, elevated levels of IL-6 and sIL-6R were found in AH of patients with uveitis. As expected, the maximal IL-6 and sIL-6R values were observed in the patients with uveitis of exogenous etiology (1558.3 and 1326.2 pg/ml, respectively). sIL-6R was also significantly elevated in AH of patients with HLA-B27( +) anterior uveitis (p<0. 01). In all individuals under study, sIL-6R levels in AH samples were 2-10 times higher than IL-6 levels. In serum samples, sIL-6R level were 10000 times higher than corresponding IL-6 values. CONCLUSION: The results confirmed the role of IL-6 in intraocular inflammation and gave new information regarding the presence of its sR in normal and inflamed eyes. Low levels of sIL-6R in AH compared to those found in serum suggest the presence of active local regulatory mechanisms that require further investigation.

Adult↗
PubMed1983

Effect of timolol on aqueous humor protein concentration in humans.

Short-term topical application of timolol, in a prospective, randomized, double-masked study of 32 human eyes, was associated with an average aqueous humor protein concentration of 38 mg/100 ml, compared to 13 mg/100 ml in control subjects (P less than .001). This apparent influence of timolol on aqueous protein levels probably resulted from reduced aqueous production. It did not affect the course of intraocular surgery.

Aged↗
PubMed2025

Stage-dependent proteomic alterations in aqueous humor of diabetic retinopathy patients based on data-independent acquisition and parallel reaction monitoring.

BACKGROUND: Diabetic retinopathy (DR), a microvascular complication of diabetes mellitus (DM), represents the predominant cause of preventable vision loss in working-age populations globally. While the pathophysiological mechanisms underlying DR progression remain incompletely understood, our study employs comprehensive proteomic profiling of aqueous humor (AH) to identify stage-specific biomarkers and therapeutic targets in type 2 diabetes mellitus (T2DM) patients across DR progression. METHODS: Utilizing data-independent acquisition (DIA) mass spectrometry, we quantified AH proteomes in a discovery cohort comprising 24 subjects: 18 T2DM patients stratified by DR severity [6 non-DR, 6 non-proliferative DR (NPDR), 6 proliferative DR (PDR)] and 6 cataract controls without diabetes (non-DM). Validation cohort analysis (including 10 AH samples in each group) was performed using parallel reaction monitoring (PRM) strategy for verification of target proteins. Comprehensive bioinformatics analyses included gene set enrichment analysis (GSEA), weighted gene co-expression network analysis (WGCNA), Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis, protein-protein interaction (PPI) network construction, receiver operating characteristic (ROC) curve analysis, and ConnectivityMap (Cmap)-based drug prediction. RESULTS: Proteomic profiling identified 739 quantifiable AH proteins (62% extracellular) with clear separation among the four clinical stages in the discovery cohort. GSEA uncovered altered expression of proteins mainly related to complement and coagulation cascades, folate metabolism, and the selenium micronutrient network in patients with DR. WGCNA-derived protein modules yielded 83 PRM-validated targets, including 5 hub proteins differentiating NPDR from non-DR and 33 hub proteins showed significant upregulation in PDR versus NPDR comparison. Clinical correlation analysis identified F2, FGG, FGB, RBP4, AMBP, VTN, C8A, CPB2, and C2 associated with clinical traits. C6, FAM3C, SPP1, and JCHAIN levels were altered post-anti-VEGF treatment. Pharmacological prediction identified potential therapeutic compounds, including perindopril, triciribine, and XAV-939 for NPDR, and topiramate, triciribine, and vecuronium for PDR. CONCLUSION: This study established a comprehensive AH proteomic signature of DR progression, offering insights into the pathogenesis of DR and highlighting potential biomarkers and novel therapeutic targets.

Humans↗