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Results for “Aqueous Humor”

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At least 433 records · Page 24Linked to original sources
PubMed1996

[Changes of some physicochemical parameters of gas exchange in aqueous humor of rabbits during treatment of experimental uveitis].

PURPOSE: To evaluate the usefulness of some parameters of the aqueous humor: pH, pO2 (oxygen pressure), pCO2 (carbon dioxide pressure) and HCO3- concentration in the diagnosis of uveitis. Changes of these parameters following conventional treatment and cryotherapy have also been investigated. MATERIAL AND METHOD: We used 40 grey rabbits (weighing 2.5-3.0 kg). Uveitis was evoked by intravitreal injection of 5 mg of animal albumin. Cryotherapy was performed by transconjunctival, quintuple cryoapplication (30 s) over ciliary body. Samples of aqueous humor were collected 6, 12, 24 and 48 hours after albumin injection. pH, pO2, pCO2 values and HCO3- concentration were determined using Astrup microanalyser. RESULTS: Parameters of aqueous humor, especially pH, pCO2 and HCO3- turned out to be fairly sensitive indicators reflecting the natural history of experimental uveitis. Cryotherapy characteristically modulates the pH, pCO2 and HCO3- values in the anterior chamber. CONCLUSIONS: We came to the conclusion that monitoring of these parameters may give some important information about the intensity of the course of uveitis and the influence of the treatment. Normalisation of the values usually parallels clinical improvement.

Albumins↗
PubMed1995

Mitomycin-C concentration in human ocular aqueous humor after topical administration during trabeculectomy.

UNLABELLED: The concentration of the antitumor antibiotic mitomycin (CAS 50-07-7, mitomycin C, MMC), used in ophthalmic surgery for its antiproliferative effects, was measured in the aqueous humor of 7 glaucoma patients undergoing trabeculectomy. Sponges soaked with MMC-solution (100 microliters of MMC-solution 0.2 mg/ml: 20 micrograms) were applied intraoperatively on the scleral flap for 5 min. 100 to 200 microliters of aqueous humor were drawn with a needle 10 min following the end of topical MMC-treatment. Samples were assayed for MMC using a reverse-phase HPLC-system with ultraviolet detection (C18-column, elution: phosphate buffer (0.01 mol/l, pH: 6.5): methanol, v:v = 70:30, 365 nm). Swabs were extracted in phosphate-buffer (0.1 mol/l, pH: 7.0) before HPLC-analysis. External calibration was used for MMC quantitation. Quantitation limit was 10 ng/ml. In all aqueous humor samples MMC-concentration was below 10 ng/ml. MMC in the swabs amounted to 37% of the MMC amount applied. CONCLUSION: After intraoperative topical application, the MMC concentration in the aqueous humor of patients is very low. The substantial loss of MMC from the swabs used for the topical MMC-treatment suggests 1. rapid systemic absorption of MMC and/or 2. a loss through irrigation of the operative field following topical MMC-application.

Administration, Topical↗
PubMed1995

Simultaneous measurement of reduced and oxidized glutathione in human aqueous humor and cataracts by electrochemical detection.

A sensitive, electrochemical method was employed for the simultaneous measurement of reduced and oxidized glutathione in lens cortex, nucleus and capsule epithelia of rabbit lenses, normal human lenses and human cataracts. In addition, aqueous humor from cataract patients was also analyzed. The level of GSSG in the nucleus of human cataracts was significantly higher than that in the nucleus of normal eye bank lenses. The capsule epithelium of intracapsular extracted cataracts possessed high levels of reduced glutathione, despite the fact that much of the glutathione in the cortex and nucleus of the lenses was depleted. Levels of GSH in the aqueous humor of cataract patients were several times higher than those reported for normal aqueous humor. Electrochemical detection proved to be a useful technique for analysis of reduced and oxidized glutathione in lens and aqueous humor, especially when sample size is small, such as for capsule epithelium.

Aged↗
PubMed2006

Prevalence of anti-Toxoplasma gondii antibodies in serum and aqueous humor samples from cats with uveitis or systemic diseases in France.

Anti-Toxoplasma gondii antibodies were determined in serum and aqueous humor of two groups of cats in France: cats with uveitis (group 1, n=26) and cats with systemic disease (group 2, n=24) using an agglutination test. Titres above 1:64 were considered positive. IgG antibodies to T. gondii were detected in 10 serum samples from group 1 and in 10 serum samples from group 2, and in 2 aqueous humor samples from group 1 and in 1 aqueous humor samples from group 2. The distribution of ocular lesions according to the serological status of the animals indicated that lens luxation and buphthalmia were more frequent in T. gondii seropositive cats than in seronegative ones. The study reports a similar prevalence of anti-T. gondii antibodies in cats with uveitis and in cats without uveitis in France. Serological results must be analysed carefully and additional diagnostic tools is required.

Agglutination Tests↗
PubMed1998

Additive effect of dorzolamide on aqueous humor flow in patients receiving long-term treatment with timolol.

OBJECTIVE: To determine the additive effect on aqueous humor flow of short-term dorzolamide treatment in patients with glaucoma receiving long-term treatment with timolol. SUBJECTS AND METHODS: Thirty-nine patients with glaucoma, 19 at Mayo Clinic, Rochester, Minn, and 20 at the University of Uppsala, Uppsala, Sweden, who had been receiving timolol treatment in both eyes for at least 1 year were studied. Aqueous flow was measured with fluorophotometry and intraocular pressure with tonometry. The effect of dorzolamide was compared with placebo when added to the long-term treatment regimen with timolol. RESULTS: Dorzolamide reduced aqueous humor flow by 24% +/- 11% (mean +/- SD). The intraocular pressure as compared with placebo in the US cohort was reduced by 10% +/- 6% and in the Swedish cohort by 18% +/- 9%. CONCLUSIONS: Dorzolamide, a carbonic anhydrase inhibitor, has additive effects as an ocular hypotensive agent with timolol, a beta-adrenergic antagonist, even though both drugs are suppressors of aqueous humor flow. Dorzolamide's effect on flow in these patients is the same as reported previously in normal subjects who are not taking a beta-adrenergic antagonist.

Adrenergic beta-Antagonists↗
PubMed2002

Nitric oxide levels in the aqueous humor in cataract patients.

PURPOSE: To determine the role of nitric oxide (NO) in the clinical manifestations of cataract in different age and etiological groups. SETTING: Multicenter study, Taipei, Taiwan, Republic of China. METHODS: Aqueous humor samples were obtained from 114 cataract patients in different etiological and age groups (eg, juvenile, traumatic, and age-related cataract). Using chemiluminescence assay, NO was detected through the light generated by ozone and NO interaction. The amount of NO production was calculated and compared among groups. The results were correlated with patient age. RESULTS: The NO levels in aqueous humor were highest in the 12 patients with traumatic cataract and lowest in the 15 patients with juvenile cataract (47.59 micromol/L +/- 12.81 [SD] and 7.66 +/- 2.62 micromol/L, respectively; P <.001). Aqueous humor NO levels were correlated with age and were highest in patients older than 80 years (mean 38.78 +/- 6.29 micromol/L) and in those with mature cataract (mean 40.15 +/- 6.15 micromol/L) (P <.05). CONCLUSIONS: The NO levels in the aqueous humor increased with age and traumatic events. The results suggest that NO could be a risk factor in cataract formation.

Adolescent↗
PubMed1993

Aqueous humor dynamics in low-tension glaucoma.

We measured the diurnal aqueous humor flow in patients with low-tension glaucoma by clearance of topically applied fluorescein. Ten patients with low-tension glaucoma participated in the study, and ten age-matched healthy volunteers served as control subjects. The diurnal aqueous humor flow was 2.58 +/- 0.78 microliters/min (mean +/- standard deviation) in the control group and 2.48 +/- 0.61 microliters/min in the low-tension glaucoma group. The corresponding nocturnal data were 0.98 +/- 0.22 microliters/min and 1.24 +/- 0.45 microliters/min. The differences were not statistically significant. Tonographic facility of outflow and intraocular pressure were also measured. There were no statistically significant differences between the two groups in either facility or pressure. No evidence was found in this small group of patients to support the hypothesis that the normal tension in this disease results from a combination of low facility and low flow.

Aged↗
PubMed1990

Detection of hepatitis B surface antigen in aqueous humor.

We detected hepatitis B surface antigen (HBsAg) in tears and aqueous humor of 18 patients who upon preliminary examination were seropositive for HBsAg and were scheduled to undergo cataract extractions. HBsAg remained detectable in the serum of 10 of these patients on the day of operation, and of these, 7 were found to have detectable levels of HBsAg in their tears and aqueous humor. Based on our findings, we caution ophthalmologists to take all the necessary precautions in both surgical and nonsurgical treatment of patients at high risk for hepatitis B infection.

Aqueous Humor↗
PubMed2003

Effects of ibopamine eye drops on intraocular pressure and aqueous humor flow in healthy volunteers and patients with open-angle glaucoma.

PURPOSE: On the basis of intraocular pressure measurements and fluorophotometry we assessed the effects of 2% ibopamine eye drops on aqueous humor production in normal and glaucomatous eyes. METHODS: Thirty subjects (15 healthy volunteers and 15 open-angle glaucoma patients with ocular hypertension) were included in a placebo-controlled study with random assignment of treatment from masked containers. All subjects underwent ophthalmologic examinations and intraocular pressure (IOP) measurements. Fluorophotometry was done in both eyes at baseline (without treatment) and during treatment. Each subject was treated with 1 drop of 2% ibopamine in one eye and 1 drop of placebo in the fellow eye 30 minutes before fluorophotometric scans and every hour after the first instillation (for a total of 4 times). Safety was evaluated by recording adverse events and ocular symptoms and signs. Aqueous humor flow data were analyzed using the paired t-test, comparing ibopamine and placebo-treated eyes. RESULTS: No changes in IOP were detected in normal eyes, whereas glaucomatous eyes showed a mean increase of 4 mmHg (95% CI 3.46-4.51) from baseline. The difference in IOP between healthy eyes and those with glaucoma was significant (p < 0.0001). In normal eyes and patients with glaucoma ibopamine led to a significant increase in aqueous humor flow compared with placebo-treated eyes (p < 0.01). The safety profile of ibopamine was very good. CONCLUSIONS: The results seem to confirm that ibopamine increases aqueous humor production in normal and glaucomatous eyes, raising IOP only in eyes with glaucoma.

Adult↗
PubMed1992

A study of aqueous humor formation in patients with cystic fibrosis.

The circadian pattern of aqueous formation and the effect of timolol on aqueous flow was studied in 12 patients with cystic fibrosis. Cystic fibrosis is a disease characterized by a defect in a chloride channel-associated regulatory protein found in epithelial cells. Improper regulation of these chloride channels, causes abnormal composition of exocrine secretions, including respiratory tract, gastrointestinal tract, exocrine pancreas, and sweat glands. Ocular findings previously reported include abnormal endothelial cell permeability, decreased tear secretion, and abnormal tear composition. In this study, aqueous humor flow was measured by fluorophotometry. No statistically significant difference was found when flow rates measured during the morning, during the afternoon, at night, and after topical timolol treatment were compared to normal values. The conclusion is that the beta adrenergically regulated chloride selective channels defective in patients in cystic fibrosis do not play a major role in the formation of aqueous humor or they are not regulated by the cystic fibrosis transmembrane conductance regulator (CFTR).

Administration, Topical↗
PubMedDate not supplied

Aqueous humor and serum tumor necrosis factor-alpha in clinical uveitis.

OBJECTIVE: To study the local and systemic behavior of the tumor necrosis factor-alpha (TNF-alpha) in patients with active uveitis. METHODS: TNF-alpha levels were measured in aqueous humor and peripheral blood samples using an enzyme-linked immunosorbent assay from 23 patients with uveitis and 16 control patients who had been operated on for uncomplicated cataracts. RESULTS: Aqueous humor and sera of patients with uveitis showed higher levels of TNF-alpha than those of controls (p < 0.001). A comparison of cytokine levels between aqueous humor and sera showed significantly higher levels of TNF-alpha in serum than aqueous humor (p < 0.001). Correlation studies using the regression test for successive steps showed that serum TNF-alpha levels correlated with recurrent uveitis (r = 0.4150; p = 0.0489). CONCLUSIONS: TNF-alpha is a cytokine that participates actively in the pathogenesis of clinical uveitis. Our data emphasize the greater systemic than local participation of TNF-alpha. Finally, an elevated serum TNF-alpha seems to be associated with a recurrent pattern of uveitis.

Adolescent↗
PubMed1998

High levels of interleukin-12 in the aqueous humor and vitreous of patients with uveitis.

OBJECTIVE: This study aimed to investigate the role of interleukin-12 (IL-12) and interleukin-10 (IL-10) in initiation and maintenance of intraocular inflammation. DESIGN: Case series. PARTICIPANTS: Aqueous humor and vitreous levels of IL-12 and IL-10 were measured in 22 patients with uveitis undergoing cataract surgery, paracentesis of the anterior chamber, and/or vitrectomy for diagnostic reasons, and in 4 patients with cataract only. INTERVENTION: Aqueous humor and vitreous levels of IL-12 and IL-10 were measured with specific enzyme-linked immunosorbent assays. MAIN OUTCOME MEASURES: Disease activity was correlated to IL-12 levels in the aqueous humor and the vitreous of patients with uveitis. RESULTS: Cytokine levels found in the anterior chamber and the vitreous are presented in picogram/milliliter (medium; range). The highest IL-12 levels were found in patients with active uveitis (108.5 pg/ml; 72-293 pg/ml). Interleukin-12 in patients with moderate uveitis or with their disease in remission was lower (32 pg/ml; 15-94 pg/ml) than in patients with active disease (P > 0.001) but higher than in the control group (10.5 pg/ml; 9-14 pg/ml). Interleukin-10 was detectable in only 3 of 22 patients with uveitis (12 pg/ml; 9-23 pg/ml). CONCLUSION: The authors found statistically significant differences of IL-12 levels in the various patient groups (active vs. inactive vs. control). These results support the idea that these uveitis cases represent type 1 (Th1)-T lymphocyte-mediated diseases in which IL-12 plays a pivotal role in the initiation and maintenance of the intraocular inflammation. The high levels of IL-12 in the vitreous and/or aqueous humor of the patients with uveitis suggest that susceptibility or resistance to ocular autoimmunity may be connected to a genetic predisposition to an elevated Th1 response.

Aqueous Humor↗
PubMed2002

Determination of voriconazole in aqueous humor by liquid chromatography-electrospray ionization-mass spectrometry.

A novel method based on liquid chromatography-mass spectrometry with electrospray ionization (LC-MS) has been developed for analysis of voriconazole in aqueous humor. The separation was achieved on a reversed-phase C(18) column eluted by 70% acetonitrile-30% water-0.01% TFA. The correlation between the concentration of voriconazole to peak area was linear (r(2)=0.9990) between 0.04 and 60 ng, with a coefficient of variance of less than 3%. Limit of quantitation (LOQ) was estimated to be 5 ng/ml voriconazole with an injection volume of 2 microl of aqueous humor. Both intra-day and inter-day imprecision were less than 3% over the whole analytical range. Parallel analyses of voriconazole samples by LC-MS and by high-performance liquid chromatography (HPLC)-UV showed that the two methods were highly correlated (r(2)=0.9985). LC-MS was used to the determine voriconazole levels achieved in the aqueous humor of the rabbit eye, following topical application of 5 or 10 microg voriconazole in the form of eyedrops for 11 days b.i.d. The lower dosage produced an aqueous humor concentration of 7.29+/-5.84 microg/ml, while the higher dosage produced a concentration of 14.56+/-12.90 microg/ml.

Animals↗
PubMed2000

Comparison of the efficacy of betaxolol-brinzolamide and timolol-dorzolamide as suppressors of aqueous humor flow in human subjects.

OBJECTIVE: To compare the efficacy of combinations of betaxolol-brinzolamide and timolol-dorzolamide as suppressors of aqueous humor flow and ocular hypotensive agents. DESIGN: Placebo-controlled, masked comparison of the two drug combinations. PARTICIPANTS: Twenty-five normal human volunteers with the fellow eye serving as control. METHODS OR TESTING: Fluorophotometric measurement of aqueous humor flow and pneumatonometric measurement of intraocular pressure. MAIN OUTCOME MEASURES: Aqueous humor flow and intraocular pressure. RESULTS: The betaxolol-brinzolamide combination lowered aqueous flow 39% to 44%, and the timololdorzolamide combination lowered aqueous flow 51%. The betaxolol-brinzolamide combination lowered intraocular pressure 14% to 19%, and the timolol-dorzolamide combination lowered it 18% to 24%. CONCLUSIONS: Both drug combinations were effective; the timolol-dorzolamide combination appeared to be the more effective of the two after short-term exposure (24 hours).

Adrenergic beta-Antagonists↗
PubMed2000

Detection of Leptospira spp. in the aqueous humor of horses with naturally acquired recurrent uveitis.

Leptospiral organisms have long been presumed to be associated with the presence of equine recurrent uveitis. This project was undertaken to determine the presence of Leptospira spp. in the aqueous humor of horses with uveitis to determine if there was an association with inflammation. Thirty horses were determined to have recurrent uveitis based on clinical evaluation or history. Sixteen horses were judged clinically and historically to be free of uveitis and were used as controls. Aqueous humor samples were cultured and evaluated by PCR for the presence of Leptospira DNA. Serum was collected and evaluated for the presence of antibodies against five serovars in a leptospirosis panel. Twenty-one of 30 horses with recurrent uveitis and one of 16 uveitis-free horses were positive by PCR for the presence of Leptospira DNA. Six of these 21 horses with uveitis were culture positive for leptospires from the aqueous humor. Serologic results did not correlate well with the presence of Leptospira DNA or organisms in the aqueous humor. Leptospira spp. are present in a high percentage of horses with naturally occurring recurrent uveitis.

Animals↗
PubMed1999

Penetration and decay of meropenem into the human aqueous humor and vitreous.

The aim of this study was to determine the penetration of intravenously administered meropenem into the human aqueous humor and vitreous. Thirty patients about to undergo cataract surgery and fourteen patients about to undergo vitrectomy received a 2 g dose of meropenem before surgery. Specimens of aqueous humor or vitreous and blood were obtained intraoperatively and analyzed by high performance liquid chromatography (HPLC). The study was designed as a non-randomized prospective trial. Thirty min to 12 hr after administration, mean aqueous humor levels of 13.4 and 1.1 mg/l and vitreous levels between 8.94 and 1.08 mg/l were found, respectively. The peak concentrations are distinctly above the in vitro measured minimum inhibitory concentration of meropenem for 90% (MIC90) of almost all relevant gram-positive and gram-negative organisms, including Pseudomonas aeruginosa and Enterobacteriaceae. With regard to its broad spectrum, high antibacterial activity, and good penetration into ocular fluids, meropenem seems to be an alternative to currently used systemic drugs. Its usefulness in perioperative prophylaxis, as initial therapy after perforating or penetrating injuries, or in the therapy of bacterial endophthalmitis has yet to be proved.

Aqueous Humor↗
PubMed1998

Aqueous humor flow in human eyes treated with dorzolamide and different doses of acetazolamide.

OBJECTIVE: To measure the effect of topically applied 2% dorzolamide hydrochloride (Trusopt, Merck & Co Inc, Whitehouse Station, NJ) and different doses of orally administered acetazolamide (Diamox, Lederle Ophthalmic Pharmaceuticals, Pearl River, NY), alone and in combination, on aqueous humor flow. DESIGN: A randomized, double-masked, placebo-controlled study of 20 human subjects was carried out. Aqueous humor flow was measured by clearance of topically applied fluorescein. Serum standard bicarbonate and serum acetazolamide levels were analyzed. RESULTS: Treatment with dorzolamide reduced aqueous flow by 17%, and a maximum dose of acetazolamide alone reduced flow by 29%. Increasing doses of acetazolamide alone gradually decreased flow, while small doses of acetazolamide did not suppress flow further when dorzolamide was already applied topically. Serum acetazolamide concentrations rose with increasing doses of acetazolamide. Serum standard bicarbonate levels were all in the normal range. CONCLUSIONS: Treatment with dorzolamide reduced aqueous humor flow statistically significantly (2.50 microL/min vs 3.00 microL/min; P=.001) compared with placebo, but less than a maximum dose ofacetazolamide. Small doses of acetazolamide added to dorzolamide treatment did not further enhance the decrease in flow. Since there was no metabolic acidosis as measured by plasma levels of standard bicarbonate, the decrease in aqueous flow could be attributed to the direct action of the carbonic anhydrase inhibitors on the carbonic anhydrase enzymes. It is concluded that the smaller effect of dorzolamide, as compared with acetazolamide, is due to insufficient inhibition of at least 1 of the 2 carbonic anhydrase isozymes involved in aqueous humor production.

Acetazolamide↗