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Results for “Aqueous Humor”

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PubMed1995

Two-color flow cytometric analysis of activated T lymphocytes in aqueous humor of patients with endogenous vs. exogenous uveitis.

To investigate the immunopathologic role of lymphocytes in aqueous humor of patients with uveitis, we assessed activated T lymphocyte subsets stained with fluorescein isothiocyanate-labeled and phycoerythrin-labeled monoclonal antibodies in aqueous humor and in peripheral blood, using two-color flow cytometry. We divided our 25 patients into those with endogenous or exogenous uveitis. The percentages of activated T lymphocytes in uveitic aqueous humor significantly exceeded those in peripheral blood lymphocytes from patients with either disease form. CD4+HLA-DR+ lymphocytes were predominant in endogenous uveitic aqueous humor, whereas CD8+HLA-DR+ lymphocytes predominated in exogenous uveitic aqueous humor in the early stage of the disease. The percentages of CD4+HLA-DR+ lymphocytes tended to increase while those of CD8+HLA-DR+ cells tended to decrease in aqueous humor from patients in the late phase of exogenous uveitis. Our results may contribute to increasing diagnostic accuracy in patients with uveitis and to developing more rational methods of treatment.

Adult↗

PubMed1989

Fibrinolytic activity and localization of plasminogen activator in bovine vitreous body and aqueous humor.

The types, activities and concentrations of plasminogen activator (PA) were examined in the bovine vitreous body and aqueous humor. Molecular weights of PA in the vitreous body and aqueous humor were approximately 66 and 110 kilodaltons (kDa), respectively, as determined by fibrinolysis enzymography. These PA activities were neutralized by anti-human tissue PA (t-PA) IgG but not by anti-human urokinase PA (u-PA) IgG. Both findings indicated that the main PA in the vitreous body and aqueous humor is t-PA. The existence of u-PA could not be confirmed in intraocular fluids. Fibrinolytic activities measured by amidolytic assay were 0.12 +/- 0.01 IU/ml in the vitreous body and 0.04 +/- 0.02 IU/ml in the aqueous humor. High concentrations but relatively low fibrinolytic activities suggested that PA and PA inhibitor coexisted in the intraocular fluids. Moreover, unbound PA inhibitor was not detected by reverse fibrinolysis enzymography. The present study suggests that most of the PA inhibitor combines with PA and forms a complex. PA predominates over PA inhibitor in the intraocular fluids, whereas PA inhibitor predominates in the plasma. The results by Todd's fibrinolysis autography and immunohistochemical staining showed that t-PA was present in the corneal endothelial cells, which are in direct contact with the aqueous humor. This suggests that not only the vascular system but the corneal endothelial cells as well might be a source of the PA of the aqueous humor and possibly of the vitreous body also.

Animals↗

PubMed1991

Effects of atrial natriuretic factor (ANF) on intraocular pressure and aqueous humor flow in the cynomolgus monkey.

Atrial natriuretic factor (ANF: human sequence) was examined for its effects on basal and terbutaline-stimulated aqueous humor flow, intraocular pressure (IOP) and uveoscleral outflow in cynomolgus monkeys under pentobarbital anesthesia. A dilution method with radioactively labeled albumin was used for the determination of aqueous humor flow. ANF was given by i.v. infusion or intracamerally. Intracameral administration of terbutaline increased the aqueous humor flow significantly; 1.10 +/- 0.05 microliter min-1 in the control eye and 1.69 +/- 0.06 microliter min-1 in the treated eye. I.v. infusion of ANF, 97 fmol kg-1 min-1, increased the aqueous humor flow by about 44% from basal values in the control eye. There was a small but not statistically significant increase on the terbutaline-treated side. The IOP was not changed by ANF at this dose. An ANF dose of 97 pmol kg-1 min-1 increased the aqueous humor flow by 51% in the control eye and by 19% in the terbutaline-treated eye. A further rise of about 8% in aqueous humor flow was registered on the control side when the infused ANF-dose was doubled. Doubling the dose also resulted in a decrease of the IOP by 1.3 +/- 0.3 mmHg on the control side and 2.2 +/- 0.4 mmHg on the terbutaline-stimulated side. Intracameral administration of ANF (81-162 pmol ml-1 perfusion fluid) increased the aqueous humor flow transiently by approximately 50% with a maximum after about 2 hr. The uveoscleral outflow tended to increase and IOP tended to decrease in the ANF-treated eye compared with the control. However, these effects were not statistically significant. These results suggest that ANF may be involved in the control of aqueous humor formation.

Animals↗

PubMed1980

Cefaclor levels in human aqueous humor.

In an attempt to investigate penetration of cefaclor into human aqueous humor, we administered 500-mg and 1-g doses of cefaclor to 39 patients about to undergo cataract extraction. Average aqueous humor levels of 0.27, 0.27, and 0.17 microgram/mL were achieved at 1, 2, and 4 hours, respectively, after the 500-mg oral dose. After 1 g orally, we found average aqueous humor levels of 0.61, 0.64, 0.72, 0.4, and 0.31 microgram/mL at 1, 2, 3, 4, and 5 hours, respectively. Therapeutic levels in primary aqueous humor were consistently achieved against Streptococcus pneumoniae and St pyogenes, group A.

Aqueous Humor↗

PubMed1992

Urokinase-type plasminogen activator in human aqueous humor.

In the anterior segment of the eye, fibrin clots must be rapidly resorbed to prevent further fibrosis and scarring. The aqueous humor of patients undergoing cataract surgery was analyzed for the presence of components of the fibrinolytic cascade. In 30 patients, aqueous humor and plasma were compared for their content of urokinase-type plasminogen activator (uPA), tissue-type plasminogen activator (tPA), plasminogen activators inhibitors (PAIs), plasminogen, and total proteins. With gel electrophoresis and zymographic assays of serial dilutions of plasma and aqueous humor, all these components were found to be present at lower concentrations in aqueous humor than in plasma. For total proteins, the aqueous/plasma ratio was approximately 0.003, and for plasminogen it was 0.001. Interestingly, the aqueous/plasma ratio for uPA was not as low and varied from 0.01 to 0.03. A significant proportion of the uPA in aqueous humor was present in the two-chain active form. In addition to uPA, aqueous humor contained lower levels of tPA, but no detectable levels of reactive plasminogen activators inhibitors (PAIs). The presence of a relatively high concentration of active uPA shows that the proteolytic balance of the aqueous humor in the anterior chamber of the eye is shifted toward fibrinolysis.

Aqueous Humor↗

PubMed1991

Identification of transforming growth factor-beta as an immunosuppressive factor in aqueous humor.

The anterior chamber of the eye is an immunologically privileged site. Over the past 15 years, numerous laboratories documented that the privileged status of this unique site is mediated by multifactorial immunoregulatory processes. Among the participating factors is the aqueous humor that circulates in the anterior chamber and is in contact with most of the tissues in the anterior segment of the eye. Recently, it was found that normal aqueous humor is a powerful inhibitor of antigen-driven T lymphocyte activation, but it spares other important functional properties of T cells. The spectrum of immune inhibitory properties resembles some of the activities of transforming growth factor-beta (TGF-beta), a polypeptide cytokine. Because of this similarity, the authors tried to determine if TGF-beta is present in aqueous humor and whether this cytokine could account for the lymphocyte inhibitory activity of this biologic fluid. They found TGF-beta in aqueous humor by dot-blot analysis. Using the CCL-64 mink lung epithelial cell bioassay for this compound, TGF-beta bioactivity was shown in aqueous humor from several different species, including human. In rabbit and human aqueous humor, most of the biologic activity was due to TGF-beta 2 (80-90%). Dose-response curves generated by using purified porcine TGF-beta showed that aqueous humor contained sufficient concentrations of TGF-beta to account for the observed inhibition in several assays for T cell activation and proliferation. Partial purification of the lymphocyte inhibitor in rabbit aqueous humor by size exclusion in high-performance liquid chromatography demonstrated that several lymphocyte inhibitory fractions contained TGF-beta bioactivity. Finally, neutralizing antisera to TGF-beta 2 were able to reverse most of the lymphocyte inhibitory activity of aqueous humor. It was concluded that TGF-beta was present in high concentration in normal aqueous humor and that this cytokine contributed to the immunosuppressive properties of aqueous humor.

Animals↗

PubMed1991

[Influence of cataract and posterior chamber lens implantation on the dynamics of the aqueous humor. Prospective study in fluorophotometry].

The influence of posterior chamber lens implantation on the aqueous humor dynamics was investigated using anterior chamber fluorophotometry before and 9 weeks after cataract extraction and IOL implantation. 34 Patients finished the protocol. Patients with preexisting glaucoma or those having a history of ocular or systemic inflammation were excluded from the study, also those taking topical or systemic drugs with potential influence on the aqueous humor dynamics. 9 weeks after IOL implantation, a mean increase in aqueous humor flow was notified. This increase was highly significant (p less than 0.01, Students paired t-test). There were no significant changes in aqueous humor dynamics in the unoperated, fellow eyes which served as controls. The significant difference of aqueous humor flow 9 weeks after cataract extraction and IOL implantation indicates that the liberation of prostaglandins may cause an increase of outflow facility as well as pseudo-facility.

Aged↗

PubMedDate not supplied

Physiology and pharmacology of aqueous humor inflow.

Recent physiological and pharmacological data pertinent to aqueous humor inflow regulation have been reviewed. New anatomical and electrophysiological data are presented, particularly related to aqueous humor secretion. The action of adrenergic agonists and antagonists is discussed in relation to changes in intraocular pressure, and the effects of a variety of experimental perturbations is presented. The multiple factors which affect aqueous humor inflow are discussed in the context of an evaluation of recent pertinent literature.

Animals↗

PubMed2006

Aqueous humor enhances the proliferation of rat retinal precursor cells in culture, and this effect is partially reproduced by ascorbic acid.

Aqueous humor has been shown to influence the proliferation of various ocular cell types, but the effect on immature retinal cells is not known. Here, the effect of pig aqueous humor on the proliferation of rat retinal precursor cells (RPCs) was investigated. RPCs were prepared from embryonic day 19 Sprague-Dawley rats and cultured in the presence or absence of aqueous humor from healthy pigs along with a medium consisting of Dulbecco's modified Eagle's medium:Ham's F-12 medium, N2 supplement, and epidermal growth factor. Proliferation was quantified by [(3)H]thymidine incorporation under different treatment conditions, and any associated morphological changes were noted. Potential active components of porcine aqueous humor were partially characterized by gel filtration chromatography, and the effect on RPC proliferation was determined. Results showed that adding 20% aqueous humor increased [(3)H]thymidine incorporation by as much as 317%, as compared with controls. Aqueous supplementation also increased both the number and size of RPC spherical aggregates ("spheres") over the first 4 days, consistent with increased proliferative activity. Using gel filtration and the in vitro proliferation assay, the growth-promoting activity of aqueous humor was localized to two different molecular mass ranges, namely, around 30 kDa and less than 1 kDa. Ascorbic acid was present in the lower molecular mass fraction, and use of this molecule reproduced some, but not all, of the proliferative activity present in aqueous humor. These results highlight the potential role of soluble factors present in the cellular microenvironment with respect to modulation of endogenous progenitor cell activity.

Animals↗

PubMed1960

Osmotic pressure and aqueous humor formation in dogfish.

Comparative chemical analyses show the aqueous humor of smooth dogfish has lower concentrations of urea and trimethylamine oxide than the blood plasma. Freezing-point depression determinations demonstrate that the aqueous humor has a correspondingly lower osmotic pressure. It would appear that water entering the aqueous humor from the plasma is moving against an osmotic gradient.

Animals↗

PubMed2004

The contribution of aqueous humor cytology in the differential diagnosis of anterior uvea inflammations.

BACKGROUND: Cytology of the aqueous humor can confirm the diagnosis of many intraocular conditions by revealing inflammatory cells, ghost red cells, lens material, and microorganisms. PURPOSE: The purpose of this study was to emphasize the contribution of aqueous humor fine needle aspiration cytology in cases where there is a clinical diagnostic dilemma whether an infectious or a noninfectious inflammatory process of the uvea is present. METHODS: Collection of 0.15-0.2 ml aqueous humor was carried out with an insulin needle. The aspirated aqueous was then prepared for examination using either the Cytospin or the Thin-Prep technique and smears were stained with modified Papanikolaou and May-Grünwald-Giemsa stains. RESULTS: Cytology of the aqueous humor essentially facilitated the differential diagnosis in 16 cases with an anterior uveal inflammation clinical picture. The cases included phacoanaphylactic endophthalmitis (n = 6), chronic postoperative bacterial endophthalmitis (n = 3), phacolytic glaucoma (n = 2), ghost cell glaucoma (n = 2), metastatic endophthalmitis (n = 1), post-traumatic lenticular abscess (n = 1), and iridocyclitis (n = 1). Treatment of the cases was successful. CONCLUSIONS: In selected cases, cytology of the aqueous humor reveals specific, with regard to the clinical entity, cell populations and other elements and thus contributes effectively to the differential diagnosis and therapeutic approach to some anterior uvea inflammations.

Adult↗

PubMedDate not supplied

The penetration of ofloxacin into human aqueous humor given by various routes.

This study was designed to measure the concentration of ofloxacin in aqueous humor after topical, oral and intravenous administration in 50 patients undergoing cataract extraction. In Group 1, ofloxacin 0.3% eyedrops were topically instilled ten times and the aqueous humor concentration was 2.73 +/- 0.88 microg/ml. In Group 2, ofloxacin 0.3% eyedrops were topically instilled six times and the aqueous humor concentration was 0.84 +/- 0.61 microg/ml. Aqueous humor concentration 12 hours after 200 mg oral dose in Group 3, was 0.38 +/- 0.12 microg/ml. In Group 4, patients were given ofloxacin as a single intravenous 200 mg dose and the aqueous humor concentration 2 hours after the end of infusion was 0.45 +/- 0.11 microg/ml. Concentrations were determined by high performance liquid chromatography (HPLC) with fluorescence detection. There was a significant difference between Group 1 and the other groups, but not between Group 2 and Groups 3, 4. It was concluded that ofloxacin penetrates the corneal and the blood-aqueous barriers and can achieve good aqueous levels when given topically and systematically. Ofloxacin can be applied topically for external bacterial infections such as conjunctivitis and keratitis. Systematically administered ofloxacin reached higher levels than the MIC for some bacteria which cause endophthalmitis.

Administration, Oral↗

PubMed1999

X-ray microanalytical and morphological observations of aqueous humor from cataract human eyes with and without diabetes mellitus.

This study was conducted to determine the elemental composition of the aqueous humor in cataract human eyes, with and without diabetes mellitus. The aqueous humor was obtained during cataract surgery from 11 patients with diabetes mellitus and 11 controls. Droplets of aqueous humor, after air-drying on carbon plates, were analyzed by X-ray microanalysis. Before surgery, the protein concentration in the anterior chamber was measured with a laser flare meter. Flare intensity was significantly higher in eyes with diabetes mellitus than in controls (p < 0.05). The X-ray microanalytical results showed that the relative sulfur content in the aqueous humor was significantly higher in the diabetic eyes than in the controls (p < 0.05). The content of elements representing the mobile ions in the aqueous humor, i.e., Na, Cl, K, and Ca was similar in both studied groups. We conclude from these data that the high sulfur content in aqueous humor of diabetic eyes may be related to a higher level of proteins found in the humor in these eyes.

Aged↗

PubMed1994

[Physiologic aging in aqueous humor minute volume of the human eye].

In 148 healthy volunteers and 75 older patients the physiological aqueous humor secretion was calculated during the afternoon hours (13.00 to 20.00 hours) using the anterior chamber protocol of Fluorotron Master II (Coherent, Palo Alto, USA). Fluorescein eye drops were applied topically to each eye five times, 5 h before measurements. Healthy volunteers as well as patients had no history of ocular pathology, surgery or laser treatment. Further exclusion criteria were hypertension, diabetes, local and systemic drug therapy, neoplasia, kidney or liver diseases, contact lens, ocular trauma. Mean age of volunteers was 26.5 +/- 3.8 years; mean age of patients was 65.5 +/- 10.5 years. The aqueous humor flow in healthy volunteers (mean +/- standard deviation) was 2.26 +/- 1.0 microliters/min and in the older patients 1.91 +/- 1.1 microliters/min. Correlation coefficient between right and left eyes in the younger volunteers: r = 0.8; in the older patients: r = 0.54. The Mann-Whitney-U-test revealed a significant difference comparing mean aqueous humor flow in healthy volunteers with the mean aqueous humor flow in older patients (P < 0.01). The results in our study underline that the mean aqueous secretion does decrease with age of about 2.5% per decade. However, to date we do not know whether eyes with primary open-angle glaucoma or ocular hypertension show such a decrease in aqueous humor flow with age or whether there is an autoregulation mechanism in eyes with primary open-angle glaucoma that decreases aqueous humor secretion in relation to an increase of outflow facility.

Adult↗

PubMed1998

The effect of aqueous humor ascorbate on ultraviolet-B-induced DNA damage in lens epithelium.

PURPOSE: High levels of ascorbic acid are known to be present in the aqueous humor of many diurnal species, whereas nocturnal animals have low concentrations of the compound. The purpose of this study was to test the hypothesis that the high concentration of aqueous ascorbate in diurnal animals protects the lens against ultraviolet (UV)-induced damage to the eye. This study compares the effect of UV-B-induced DNA strand breaks on the lens epithelia of guinea pigs and rats after depletion or elevation of aqueous humor ascorbate, respectively. METHODS: Eyes of guinea pigs and rats were exposed to UV-B radiation (0.25-0.75 J/cm2 on the cornea) for 10 minutes, and DNA strand breaks in lens epithelium were measured by single-cell gel electrophoresis. Ascorbic acid concentration in the aqueous humor, lens, and lens-capsule epithelium were assayed by spectrophotometric and electrochemical methods. For depletion of aqueous humor and lens ascorbate in guinea pigs, the animals were maintained on an ascorbate-deficient diet. Aqueous ascorbic acid was elevated in the rat by intraperitoneal injections of sodium ascorbate (1 g/kg). RESULTS: The ascorbate concentration in the aqueous humor of the normal rat was approximately 3% that of the guinea pig, whereas the concentration of the compound in the lens of the normal rat was 10% that of the guinea pig. Guinea pigs fed an ascorbate-deficient diet showed a dramatic drop of more than 80% in aqueous humor ascorbate in the first week, whereas lens ascorbate decreased by approximately 25% during this time period. After a single intraperitoneal injection of sodium ascorbate in the rat, aqueous humor ascorbic acid increased nearly 30 times that in the control, whereas lens ascorbate increased by approximately 30%. The extent of DNA damage in the lens epithelium of a normal rat exposed to UV-B was significantly greater than that occurring in lenses of normal guinea pigs after exposure to the same dose of radiation. Lenses from ascorbate-deficient guinea pigs showed 50% more DNA damage than those from normal guinea pigs after UV exposure, whereas the lenses in ascorbate-injected rats exhibited significant protection against UV-induced DNA strand breaks. CONCLUSIONS: High levels of ascorbic acid in the aqueous humor had a protective effect against UV-induced DNA damage to lens epithelium. The results were consistent with the hypothesis that high ascorbic acid in diurnal animals protects the lens against the cataractogenic effect of UV radiation in sunlight.

Animals↗

PubMed1999

[Cathepsin A activity in the aqueous humor in patients with cataract, absolute glaucoma and intraocular tumors].

PURPOSE: To evaluate cathepsin A activity in the aqueous humor of patients with cataract, absolute glaucoma and intraocular tumors. MATERIAL AND METHODS: The studies were performed on human aqueous humor taken from anterior chamber of eye balls of patients operated because of cataract, absolute glaucoma and intraocular tumors. Cathepsin A activity was determined by the ninhydrin method with synthetic substrate (N-Cbz-Phe-Ala) at its optimum pH 5.0. RESULTS: In the human aqueous humor of the eye with cataract cathepsin A activity was more than three times higher than in the eye with choroid tumors and absolute glaucoma. No differences of enzyme activity in aqueous humor between patients with glaucoma and intraocular tumors were found. CONCLUSION: The increasing proteolytic activity of cathepsin A in aqueous humor of patients with cataract suggests its importance in cataract pathogenesis. This implies that cathepsin A is involved in development of lens opacity and is found in the aqueous humor due to diffusion from cataractous lens in which the proteolytic process prevails.

Aqueous Humor↗

PubMed2001

Relationship between aqueous humor protein level and outflow facility in patients with uveitis.

PURPOSE: To determine whether there is a relationship between the aqueous humor protein level and outflow facility in patients with uveitis. METHODS: Aqueous humor protein levels were determined by laser flare photometry, and outflow facility was determined by Schiotz tonography. RESULTS: Thirty patients with uveitis and 10 control subjects were studied. Outflow facility was lower in patients with uveitis (0.21 +/- 0.12 microl/min x mm Hg) than in control subjects (0.33 +/- 0.05 microl/min x mm Hg, P < 0.001). Patients with uveitis and laser flare photometry results (flare) more than 20 photon units/msec (n = 21) had a lower outflow facility (0.17 +/- 0.07 microl/min x mm Hg) than patients with uveitis and flare less than 20 photon units/msec (n = 9, 0.32 +/- 0.14 microl/min x mm Hg, P = 0.004). Furthermore, no difference was identified between outflow facility in patients with active uveitis (those who had anterior chamber cells) and flare less than 20 photon units/msec and outflow in control subjects. In patients with uveitis, there was a linear correlation between flare and outflow facility (r = -0.50, P = 0.005). There was no relationship between flare measurements and either intraocular pressure or aqueous humor cell levels when scored with a clinical, semiquantitative system. CONCLUSIONS: Outflow facility is significantly reduced in patients with uveitis who have high aqueous humor protein levels. Outflow facility appears to be normal in patients with active uveitis whose flare levels are low, and therefore the association between flare and outflow facility does not appear to be an indirect reflection of elevated anterior chamber cells. It is possible that elevated aqueous humor protein levels contribute to the development of uveitic glaucoma in some individuals by decreasing aqueous humor outflow facility, although a causal relationship cannot be established on the basis of this study.

Adult↗

PubMed1991

Effects of topical dihydroergocristine on intraocular pressure, aqueous humor dynamics and pupil diameter in conscious rabbits. A comparative study with timolol and pilocarpine.

This work comparatively studies the effects of dihydroergocristine, timolol and pilocarpine on intraocular pressure and pupil diameter in conscious rabbits. Intraocular pressure was measured by applanation tonometry and the pupil diameter by a photographic technique. In anesthetized rabbits, changes in tonographic facility of aqueous humor outflow and rate of aqueous humor formation were evaluated. Dihydroergocristine reduced the intraocular pressure more than timolol and much more than pilocarpine. The ocular hypotensive effect of dihydroergocristine was accomplished by a great reduction in aqueous humor formation, which surpasses the decrease in aqueous humor outflow, while timolol mainly reduced aqueous humor formation and pilocarpine increased aqueous humor outflow. Pupil diameter remained unchanged on dihydroergocristine, whereas timolol induced a slight mydriasis and pilocarpine provoked a clear myosis. Effects of dihydroergocristine might result in blockade of alpha-adrenoceptors in ciliary body, although available data about pretreatment with either metoclopramide or domperidone suggest that dopamine DA2-receptors might participate in ocular hypotensive effect of ergot derivatives.

Administration, Topical↗