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Results for “Aqueous Humor”

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PubMed2003

Increased levels of Helicobacter pylori IgG antibodies in aqueous humor of patients with primary open-angle and exfoliation glaucoma.

PURPOSE: A prospective, nonrandomized, comparative study was carried out to investigate the levels of anti- H. pylori-specific IgG antibodies in the aqueous humor and serum of patients with primary open-angle glaucoma (POAG) and patients with exfoliation glaucoma (XFG), and to compare them with those in age-matched cataract patients. METHODS: Aqueous humor was aspirated at the beginning of glaucoma surgery from 26 eyes of 26 patients with POAG, 27 eyes of 27 patients with XFG, and at the beginning of phakoemulsification cataract surgery from 31 eyes of 31 age-matched normotensive cataract patients. Serum samples were obtained the day before surgery from all patients. Anti- H. pylori IgG concentration in the aqueous humor and serum was measured by means of an enzyme-linked immunosorbent assay. RESULTS: The mean concentration (+/- SE) of anti- H. pylori-specific IgG was significantly greater in the aqueous humor samples from patients with POAG (14.27+/-3.86 U/ml) and XFG (14.25+/-3.39 U/ml) than in those from age-matched control cataract patients (4.67+/-1.07 U/ml); ( P=0.006 and P=0.003, respectively). No difference was observed in the levels of H. pylori-specific IgG antibodies between POAG and XFG aqueous humor samples ( P=0.5). Similarly, the serum concentration of anti- H. pylori antibodies was significantly greater in patients with POAG (69.96+/-9.69 U/ml; P=0.013) and XFG (81.37+/-10.62 U/ml; P=0.002) than in the cataract controls (44.16+/-6.48 U/ml). The mean vertical cupping correlated significantly with the titer of anti- H. pylori-specific IgG in the aqueous humor in the POAG patients. CONCLUSION: H. pylori-specific IgG antibody levels are significantly increased in the aqueous humor and serum of patients with POAG and XFG. Moreover, the titer of anti- H. pylori antibody in the aqueous humor might reflect the severity of glaucomatous damage in POAG patients. These findings support a role for H. pylori infection in the pathobiology of these two common glaucomas.

Adult↗

PubMed1986

Effects of vasoactive intestinal polypeptide (VIP) on intraocular pressure, facility of outflow and formation of aqueous humor in the monkey.

Stimulation of the facial nerve causes a non-cholinergic vasodilation in the uvea and a rise in the intraocular pressure in rabbits, cats and monkeys. Vasoactive intestinal polypeptide (VIP) has been suggested as the neurotransmitter mediating these effects. In the present investigation, the effects of VIP on aqueous humor dynamics were studied in cynomolgus monkeys. After intracameral injection of 1 microgram VIP, the outflow facility was higher in the experimental eye than in the control; 0.42 +/- 0.46 compared with 0.33 +/- 0.03 microliter cm H20-1 min-1, difference 0.09 +/- 0.04 microliter cm H2O-1 min-1. Intravenous infusion of VIP, 160 ng min-1, increased aqueous humor flow from 1.12 +/- 0.07 to 1.65 +/- 0.09 microliter min-1. Almost the same effect, a 50% increase in aqueous humor flow, was found after intracameral administration of 90 micrograms VIP. This dose of VIP caused a significant increase in intraocular pressure (IOP) in the experimental eye. The maximal difference in IOP between the experimental eye and the control eye was 7.5 +/- 0.4 cm H2O. A lower dose of VIP, 30 micrograms intracamerally, increased aqueous humor flow by about 20%, but had no consistent effect on IOP. The effect of VIP on aqueous humor flow was not affected by pretreatment with indomethacin. The results suggest that most of the rise in IOP caused by intracameral VIP administration is due to a rise in the pressure in the veins into which the aqueous humor is drained. Enhanced formation of aqueous humor plays a smaller role. The effects of VIP on aqueous humor formation and outflow facility suggest that the facial nerve may be involved in nervous control of aqueous humor dynamics, as VIP is most probably released in the eye by stimulation of the facial nerve.

Animals↗

PubMedDate not supplied

UV-Absorbing compounds in the aqueous humor from aquatic mammals and various non-mammalian vertebrates.

OBJECTIVE: To evaluate the absorbance of ultraviolet radiation (UVR) in the aqueous humor of various animal species in relation to the ambient radiation of their respective habitats, and to identify substances responsible for this absorbance. Representatives of all five classes (fish, amphibian, reptile, bird, and mammal) have been tested. METHODS: Absorbance was recorded using a spectrophotometer. The ascorbic and uric acid concentrations were determined by HPLC, and the amino acid profiles with an automatic analyzer. Screening for potential UV-absorbing substances was performed by HPLC and a total of 12 species were examined, 7 of them birds. RESULTS: UV-absorbing substances in the aqueous humor were proteins, tryptophan, tyrosine and ascorbic and uric acid. In addition, an unknown UV-absorbing component present in bird aqueous humor caused a high, red-shifted UV-absorbance spectrum, particularly in tentatively heavily exposed species such as goose when migrating at 10,000 m altitude. By comparison, the UV absorbance above the 288-nm wavelength was low in the aqueous humor of fish, frogs, aquatic mammals and two ground-living birds. The crocodile, whose aqueous humor contained significant amounts of both ascorbic and uric acid, revealed a concentration mechanism for ascorbic acid. CONCLUSIONS: The UV absorbance of aqueous humor varies considerably from one species to the next, and independent of class. It is noteworthy that the species being at highest risk for high-dose UV exposure, the migrating goose, showed the most red-shifted spectrum.

Absorption↗

PubMed1985

Angiotensin-converting enzyme activity in human aqueous humor.

We measured aqueous angiotensin-converting enzyme (ACE) activity in 37 patients. Patients with granulomatous uveitis and probable sarcoidosis (based on increased serum ACE activity or characteristic radiologic findings) had a significant increase in aqueous ACE activity compared with normal subjects. Aqueous ACE activity was also significantly elevated in patients with sarcoid who had normal serum ACE activity. We believe that measurement of aqueous ACE activity should be considered in patients with uveitis who have normal serum ACE activity and are suspected of having sarcoidosis.

Adult↗

PubMed1992

Sodium activity in the aqueous humor and corneal stroma of the rabbit.

The present study examined the free sodium concentration of the aqueous humor and corneal stroma of both transparent and non-transparent corneas to assess the transendothelial activity gradient for sodium. In the transparent cornea of the adult rabbit, the sodium activity was higher in the aqueous humor than the stroma. This difference in sodium activity would cause water to diffuse down its concentration gradient from stroma to aqueous humor. In this way corneal transparency and the deturgesced state are maintained. Removal of the corneal endothelium in the adult rabbit produced an opaque swollen cornea. Under these conditions the sodium activity was higher in the stroma than the aqueous humor. However, an osmotic gradient was not produced by the Na+ activity gradient because the endothelium was not present to act as a semi-permeable membrane. The corneal endothelium was no longer present to establish and sustain the activity gradient for sodium that is necessary for corneal transparency in the mature rabbit. The transendothelial sodium activity gradient was also measured in 13-day-old rabbits. At this age, the cornea was not yet transparent, nevertheless the free sodium concentration of the aqueous humor was higher than that of the stroma, similar to the adult transparent cornea. This suggests that forces other than the establishment of the proper transendothelial sodium gradient are responsible for the lack of corneal transparency in the young rabbit.

Animals↗

PubMed2004

[Nitric oxide level in aqueous humor in patients with glaucoma].

PURPOSE: There is increasing evidence suggesting, that nitric oxide may be implicated in the pathogenesis of glaucoma. The aim of the study was to evaluate nitric oxide level in aqueous humor of glaucoma patients. MATERIAL AND METHODS: The examined group was constituted by 26 persons (13 women and 13 men), aged 60-86 (mean age 70) suffering from glaucoma. In 14 patients glaucoma was classified as POAG and in 12 as PACG. All patients have undergone trabeculectomia. The 14 patients was operated because of age-related cataract (8 women and 6 men), aged 47-82 (mean age 65), constituted a control group. All patients agreed to samples collection. Level of nitric oxide in anterior chamber fluid was assessed using commercial kits based on Griess reaction (R&D) according to manufacturer's instruction. Statistical analysis was performed using U Mann-Whitney test. RESULTS: The mean level of nitric oxide in aqueous humor was not significantly different between glaucoma and cataract group (p=0.535). The level of NO in humor aqueous was statistically significantly lower in patients with primary open angle glaucoma than in patients with primary angle closure (p=0.022), and than in control group (p=0.053). No statistically significant differences in the level of nitric oxide in humor aqueous between PACG and cataract patients were observed (p=0.365).

Aged↗

PubMed1983

The effect of timolol on the concentrations of albumin and IgG in the aqueous humor of the human eye.

We investigated albumin and IgG concentrations in the aqueous humor of 41 patients before intracapsular cataract extraction (primary samples) and at the end of surgery (secondary samples). Albumin and IgG concentrations were determined in all samples by means of a quantitative fluoroimmunoassay. A short-term topical application of timolol in 24 eyes was associated with a significant increase in both proteins in the primary aqueous humor samples compared with 17 control samples (P less than .005). The ratios of albumin to IgG--even when corrected for serum levels--were not significantly different in the two groups. Timolol did not affect the change in these ratios in the secondary aqueous humor samples. Thus, we concluded that these findings were not caused by a breakdown of the blood-aqueous barrier, but rather resulted from reduced aqueous humor flow and undisturbed protein filtration.

Aged↗

PubMed2006

[Vascular endothelial growth factor and pigment epithelium-derived factor in aqueous humor of patients with choroidal neovascularization].

OBJECTIVE: To detect the levels of vascular endothelial growth factor (VEGF) and pigment epithelium-derived factor (PEDF) in aqueous humor of patients with active choroidal neovascularization (CNV). METHODS: Aqueous humor samples were obtained from 32 patients with active CNV. The concentrations of VEGF and PEDF in aqueous humor were measured by enzyme linked immunosorbent assay (ELISA) for quantitative analysis. VEGF and PEDF in 10 samples of aqueous humor from patients with cataract were also detected by the same methods as control. RESULT: The mean VEGF and PEDF concentrations in aqueous humor of active CNV patients were higher than those in the control group (P=0.000). CONCLUSION: The patients with active CNV exhibit significantly higher VEGF and PEDF levels than those in control, indicating that VEGF along with PEDF may modulate the formation of CNV.

Adult↗

PubMed1994

Inhibitory effect of TGF-beta 2 in human aqueous humor on bovine lens epithelial cell proliferation.

PURPOSE: To determine whether transforming growth factor-beta 2 (TGF-beta 2) in human aqueous humor inhibits the proliferation of lens epithelial cells. METHODS: Bovine lens epithelial cells (BLECs) obtained from the central zone of the anterior capsule were cultured in complete medium (F-12 nutrient mixture supplemented with 5% fetal bovine serum). Human aqueous humor was obtained from 11 patients during cataract surgery. Medium was removed and replaced with medium containing various concentrations of porcine platelet-derived TGF-beta 2 or 10% human aqueous humor, with or without anti-TGF-beta 2 neutralizing antibody. The number of cells was counted at 96 hours. RESULTS: Porcine platelet-derived TGF-beta 2 inhibited BLEC proliferation in a dose-dependent manner. Anti-TGF-beta 2 antibody blocked the inhibitory effect of TGF-beta 2 on BLEC proliferation. The 10% human aqueous humor stimulated the proliferation of BLECs. Addition of anti-TGF-beta 2 antibody to the 10% human aqueous humor significantly enhanced this stimulatory effect on BLEC proliferation. CONCLUSIONS: TGF-beta 2 in human aqueous humor inhibits the proliferation of lens epithelial cells in vitro.

Aged↗

PubMed1983

Insulin concentration in aqueous humor of rabbits: effects of alloxan-diabetes and insulin treatment.

Insulin concentrations were measured in the aqueous humors of insulin-treated and untreated diabetic rabbits. The aqueous humor insulin concentration of diabetic rabbits after feeding was less than that of normal control animals. When diabetic rabbits were treated with insulin, the aqueous humor insulin concentration rose to concentrations much greater than in normal ones. The aqueous: plasma concentration ratios of both insulin and total protein for diabetic animals were greater than those for normal ones and suggest that the permeability of the blood-aqueous barrier was greater in the diabetic rabbits. Since insulin is known to be capable of influencing the metabolism of the lens, it is conceivable that abnormal insulin concentrations in aqueous humor may influence the development of cataract in diabetes.

Animals↗

PubMed2000

Aqueous humor stimulates the migration of human trabecular meshwork cells in vitro.

PURPOSE: Depletion of trabecular meshwork cell numbers is a feature of the outflow system in aging and in primary open-angle glaucoma. It is possible that migration stimulated by factors present in aqueous humor may contribute to the cell loss. This investigation assessed the chemoattractant potential of glaucomatous and nonglaucomatous human aqueous humor and fibronectin, one of its constituents, on a range of cultured trabecular meshwork cell lines. METHODS: Migration was assessed in 48-well modified Boyden chambers. The potential migratory stimulants were soluble fibronectin and glaucomatous and nonglaucomatous aqueous humor. The glaucomatous aqueous samples were collected from patients undergoing trabeculotomy for primary open-angle glaucoma and the normal aqueous from normal bovine eyes and patients undergoing cataract surgery. The target cell types were normal human and bovine meshwork cells grown from explants and two human transformed meshwork cell lines from a normal (HTM-5) and a glaucomatous (HTM-3) source. RESULTS: Soluble fibronectin stimulated all the target cells to migrate with an optimal concentration ranging from 1 to 30 microg/ml, and Zigmond Hirsch checkerboard analysis indicated that both chemotaxis and chemokinesis took place. All the aqueous humor samples stimulated migration of the meshwork cell lines at an optimal concentration of 200 microl/ml. Glaucomatous aqueous humor stimulated a greater migratory response than nonglaucomatous aqueous for two of the four target cell types (P < or = 0.03). Neutralization of the fibronectin content of nonglaucomatous and glaucomatous aqueous by addition of excess anti-fibronectin antibody indicated that fibronectin could account for 35% to 80% of the migratory activity of the aqueous. CONCLUSIONS: Aqueous humor contains potentially powerful chemoattractants for trabecular meshwork cells. The activity of one of these constituents, fibronectin, has been accounted for by this study. Glaucomatous aqueous appears to be as good and in some cases a better migratory stimulant than nonglaucomatous aqueous in vitro. The migratory evidence points to a trend that may help to explain cell loss in the aging meshwork and possibly some of the extra loss in primary open-angle glaucoma.

Adolescent↗

PubMed1999

Penetration of ofloxacin and ciprofloxacin in aqueous humor after topical administration.

BACKGROUND AND OBJECTIVE: To compare the aqueous humor levels of 0.3% ofloxacin and 0.3% ciprofloxacin containing eyedrops in patients with healthy cornea. PATIENTS AND METHODS: Fifty patients with cataract were randomly assigned to have 0.3% ofloxacin containing eyedrop (25 patients) or 0.3% ciprofloxacin containing eyedrop (25 patients). Both drugs were repetitively instilled to each patient for 6 hours before the surgery. Aqueous samples were collected after penetrating the anterior chamber during cataract extraction and assayed by high-performance liquid chromatography method. RESULTS: The aqueous humor level of ofloxacin (1.43 +/- 0.26 microg/ml, mean +/- SEM) was significantly higher than that of ciprofloxacin (0.35 +/- 0.07 microg/ml) following the topical application (P < .0002). CONCLUSION: Aqueous humor penetration of topical ofloxacin is about 4 times higher than that of topical ciprofloxacin when the drugs are applied as described above.

Administration, Topical↗

PubMed1992

Aqueous humor messengers in the transient decrease of intraocular pressure after ganglionectomy.

Intraocular pressure (IOP) decreases in rabbits 1 day after superior cervical ganglionectomy. It was hypothesized that this IOP decrease was caused by an accumulation of norepinephrine (NE) released from the iris-ciliary body into the aqueous humor during nerve degeneration. Direct measurement of aqueous humor NE concentration, however, was not successful because of the technical difficulty. In the current study, aqueous humor NE after superior cervical ganglionectomy was extracted and quantified using high-performance liquid chromatography-electrochemical detection. Twelve New Zealand albino rabbits were maintained in a daily 12-hr light-12-hr dark environment. Unilateral ganglionectomy was done on these rabbits during the light phase under halothane anesthesia. Twenty-two hours after the procedure, a significant IOP decrease occurred. The IOP was 16.1 +/- 0.6 mmHg (mean +/- the standard error of the mean) in the operated eye and 20.9 +/- 0.6 mmHg in the contralateral eye (P < 0.01). Aqueous humor NE concentration in the operated eye (475 +/- 81 pg/ml) was not different from that in the contralateral eye (469 +/- 58 pg/ml). However, the concentration of aqueous humor cyclic adenosine monophosphate (cAMP) in the operated eye (29.8 +/- 6.8 pmol/ml) was significantly higher (P < 0.05) than that in the contralateral eye (11.7 +/- 0.8 pmol/ml). These data indicate that aqueous humor NE per se does not cause the transient IOP decrease after superior cervical ganglionectomy and cAMP-mediated ocular activities may be involved in this change in IOP.

Animals↗

PubMed2002

Aqueous humor nitric oxide levels in patients with Behçet disease.

PURPOSE: The purpose of this study was to quantify aqueous humor nitric oxide levels in patients with Behçet uveitis and age-matched controls to assess how nitric oxide is involved in this ocular condition. METHODS: Samples of aqueous humor were collected from 11 patients with Behçet uveitis who were undergoing cataract surgery. Sampling was done by paracentesis at the beginning of the operation. Similar samples were collected from 20 age-matched normal patients (controls). For each sample, we used the spectrophotometric method based on the Griess reaction to determine the amount of nitrite, which is the stable metabolite of nitric oxide. RESULTS: The amount of nitrite in aqueous humor samples from patients with Behçet disease was above the detection limit in 8 of 11 cases; the mean level +/- SEM was 2.13 +/- 0.621 micromol/L. Levels in the control group were below the detection limit in all cases (<0.08 micromol/L). There was a statistically significant difference between the aqueous humor nitrite levels in patients with Behçet disease and those in controls (P = 0.00002). CONCLUSIONS: Aqueous humor nitric oxide levels are elevated in patients with a history of Behçet disease.

Adult↗

PubMed2002

Presence of variant transthyretin in aqueous humor of a patient with familial amyloidotic polyneuropathy after liver transplantation.

To determine the origin of transthyretin (TTR) in the aqueous humor of patients with familial amyloidotic polyneuropathy (FAP), we measured TTR levels and analyzed the TTR forms in the aqueous humor of three FAP patients (one patient; liver transplanted, and two patients; non-transplanted). The total TTR levels were almost the same as reported previously in non-transplanted patients and slightly increased in a transplanted patient. Analyses with mass spectrometry in the two non-transplanted FAP ATTR V30M patients revealed that both wild type and variant TTR forms were detected in their aqueous humor samples. Moreover, variant TTR forms could be detected in the aqueous humor of the transplanted patient while the liver produced no variant TTR. These results suggest that variant TTR in aqueous humor may be derived from retina where TTR was produced. In conclusion, TTR metabolism may occur in its own ocular cycle and variant TTR produced by the retina may play an important role in amyloid formation in the ocular tissues of FAP patients.

Adult↗

PubMed1994

Effect of 8-Br cGMP on aqueous humor dynamics in monkeys.

PURPOSE: To evaluate the effect of 8-bromo cGMP (Br cGMP) on aqueous humor flow rate and outflow facility in monkey eyes. METHODS. Aqueous humor flow rate was measured fluorophotometrically after topical, intracameral, or intravitreal administration of Br cGMP in one eye and normal saline in the other eye. Outflow facility was determined by two-level constant pressure perfusion after intracameral bolus injection of Br cGMP in one eye and Bárány's solution in the other eye. RESULTS: Aqueous humor flow rate decreased by 15% to 20% after intravitreal administration of 10 or 30 micrograms of Br cGMP. There was no flow response to smaller or larger intravitreal doses nor to drugs administered via other routes. Outflow facility increased by 25% to 30% after intracameral infusion of 100 or 300 < gm > g Br cGMP, but not after smaller doses. CONCLUSIONS: cGMP may be involved in the regulation of aqueous humor formation and outflow facility and their responses to pharmacologic agents.

Administration, Topical↗

PubMed1998

Increased level of vascular endothelial growth factor in aqueous humor of patients with neovascular glaucoma.

PURPOSE: This study aimed to quantitate and compare the concentration of vascular endothelial growth factor (VEGF) in aqueous humor samples from patients with neovascular glaucoma (NVG), primary open-angle glaucoma (POAG), and cataract, as well as in serum samples of healthy human subjects. METHODS: The authors collected aqueous humor samples by using their previously published technique of limbal paracentesis. The authors determined the concentration of VEGF by using a competitive enzyme immunoassay system and four-parameter logistic curve fitting and performed statistical analysis by using the Mann-Whitney-Wilcoxon test. RESULTS: The authors detected VEGF in 12 of 12 samples from patients with NVG (mean +/- standard error of the mean, 29.267 +/- 7.350 ng/ml), 15 of 28 samples from patients with POAG (0.726 +/- 0.204 ng/ml), 4 of 20 aqueous humor samples from patients with cataract (0.257 +/- 0.043 ng/ml), and 16 of 16 human serum samples (20.246 +/- 1.568 ng/ml). The mean concentration of VEGF in aqueous humor of patients with NVG was 40- and 113-fold higher than that in patients with POAG and cataract, respectively, and the difference was statistically significant (P < 0.01). The VEGF level in patients with POAG was elevated compared with that in patients with cataract (P < 0.05). Although the mean concentration of VEGF in aqueous humor of patients with NVG was approximately 1.45-fold higher than that in serum, the difference was not significant (P > 0.05). CONCLUSION: The authors' findings show that patients with NVG had a significantly increased level of VEGF in the aqueous humor and implicate VEGF as an important factor in the pathogenesis of intraocular neovascularization in these patients. The authors discuss the possible role of the ciliary epithelium, in addition to retina, in the production of VEGF and the complementary function of basic fibroblast growth factor and other growth factors.

Aged↗

PubMed1981

In vivo aqueous humor oxygen tension--as estimated from measurements on bare stroma.

Aqueous humor oxygen tension of the in vivo rabbit eye was estimated by a relatively atraumatic procedure. The anterior corneal surface of the eye was first scraped free of its epithelial layer. A polarographic oxygen electrode was then used to measure the oxygen tension at the bare stromal surface. Aqueous humor oxygen tension can be estimated from this measured steady-state stromal surface oxygen tension by correcting the measured oxygen tension for the tension drop across the stroma and endothelium. When animals breathed room air (155 mm Hg oxygen tension), the oxygen tension of the aqueous humor was 13 mm Hg; this rose to 150 mm Hg when the inspired oxygen tension was 713 mm Hg.

Animals↗