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Results for “Aqueous Humor”

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PubMed2004

Determination of the aqueous humor volume by three-dimensional mapping of the anterior chamber.

In this study involving 12 patients planned for routine cataract surgery, we used the topography of the anterior chamber depth and the corneal diameter obtained from Orbscan II data to calculate the aqueous humor volume. Prior to the surgical procedure, a small amount of fluorescein was injected into the anterior chamber and an aqueous humor sample was taken, from which the aqueous humor volume could be calculated by fluorometry. The volumes obtained from Orbscan II data were validated by the fluorometric measurements and compared to three theoretical formulas for aqueous humor volume calculation. The aqueous humor volume calculations based on the Orbscan II data aligned better to the fluorometric values (R(2) = 0.890) than the values obtained by Heim's formula (R(2) = 0.677), Brubaker's formula (R(2) = 0.671), and Schenker's formula (R(2) = 0.585), or the assumption of a constant aqueous humor volume.

Aged↗

PubMed2004

Aqueous penetration of gatifloxacin and levofloxacin into the rabbit aqueous humor following topical dosing.

The aqueous penetration of the commercial preparations of the fluoroquinolone antibiotics ofloxacin, ciprofloxacin, levofloxacin, and gatifloxacin were compared following topical dosing in a rabbit model. Levofloxacin achieved the highest aqueous concentrations, with a mean aqueous level of 4.8014 microcg/mL (p = 0.002, p = 0.00002, p = 0.015.) Ofloxacin (2.5136 microcg/mL) and gatifloxacin (2.4817 microcg/mL) achieved statistically equal aqueous concentrations (p = 0.479). Ciprofloxacin reached the lowest levels in the aqueous humor (0.9616 microcg/mL, p = 0.00002, 0.00004, 0.008). Gatifloxacin alone achieved concentrations in excess of the MIC90s of gram-positive pathogens of concern.

Animals↗

PubMed1996

[Tissue plasminogen activator (t-PA) in aqueous humor of patients with cataract].

PURPOSE: The purpose of the examination was evaluation of tissue plasminogen activator (t-PA) concentration and plasminogen activator inhibitor (PAI) activity in aqueous humor of the eye and plasma of blood in patients operated on cataract. MATERIAL AND METHODS: In aqueous humor and citrate plasma of 24 patients undergoing cataract surgery the concentration of t-PA (Imulyse Biopool) and the activity of PAI-1 (Spectrolyse Biopool) were determined. RESULTS: In aqueous humor of 90% patients the concentration of t-PA-Ag in mean value 1.5 +/- 2.7 ng/ml was ca 20% of the level present in plasma. In aqueous humor of nearly all patients no PAI-1 activity could be detected. In a little group of persons because of small amounts of aqueous humor, other fibrinolytic parameters were also estimated and the presence of urokinase-type plasminogen activator (u-PA), alfa-2 antiplasmin (alfa-2AP) and plasmin-alfa-2 antiplasmin (PAP) complexes but no activity of protein C were observed. CONCLUSION: The presence of PAP complexes in aqueous humor indicates on intensive plasminogenesis in vivo. Our examinations confirm the role of fibrinolytic process in physiological and pathological processes occurring in the eye.

Aged↗

PubMed1995

Migration of cultured bovine trabecular meshwork cells to aqueous humor and constituents.

PURPOSE: To investigate the migration of cultured bovine trabecular meshwork cells to aqueous humor and some of its constituents, and to compare the migration of normally proliferating and growth-arrested cells. METHODS: Cellular migration was evaluated in 48-well microchemoattraction chambers, and the chemoattractants used were bovine aqueous humor, glycoproteins, and growth factors. RESULTS: The meshwork cells responded well to bovine aqueous humor, and antibody neutralization experiments showed that fibronectin accounted for approximately 40% of aqueous chemoattraction. The glycoproteins laminin, thrombospondin, and transferrin elicited only modest migratory activity. Platelet-derived growth factor was the most powerful chemoattractant of the growth factors tested, and the others produced moderate migratory effects. Basic fibroblast growth factor was not chemoattractive on its own but stimulated migration when combined with heparin. Growth-arrested cells showed less migration to a standardized chemoattractive stimulus than did proliferating meshwork cells. CONCLUSIONS: For the first time, aqueous humor was shown to act as a migratory stimulus for meshwork cells in vitro. The major attractant is fibronectin; the remaining active constituents must still be identified.

Animals↗

PubMed1991

[Effect of cataract extraction on aqueous humor dynamics in patients with senile cataract. A prospective fluorophotometric study].

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. Thirty-four patients finished the protocol. Patients with preexisting glaucoma or those having a history of ocular or systemic inflammation were excluded from the study, as were those taking topical or systemic drugs with potential influence on the aqueous humor dynamics. Nine weeks after IOL implantation a mean increase in aqueous humor flow was noted. This increase was highly significant (p less than 0.01, Student's paired t-test). There were no significant changes in aqueous humor dynamics in the unoperated fellow eyes which served as controls. The significant difference in aqueous humor flow 9 weeks after cataract extraction and IOL implantation indicates that the liberation of prostaglandins may cause an increase in the ease of outflow facility.

Aged↗

PubMed1978

Cefamandole levels in primary aqueous humor in man.

We administered cefamandole nafate to 69 patients before cataract extraction and assayed serum and aqueous humor for antibiotic content at the time of surgery. Average aqueous humor levels of 0.33, 0.59, 0.21, and 0.14 microgram/ml were achieved at one half, one, two and four hours, respectively, after a 1-g intravenous dose. After a 2-g intravenous dose, we found average aqueous humor levels of 1.26, 1.0, 1.57, 0.73, and 0.34 microgram/ml at one half, one, two, four and six hours, respectively. Therapeutic levels in primary aqueous humor effective against common grampositive pathogens were consistently achieved with the 2-g dose, but levels effective against Enterobactereaceae were attained only erratically.

Aqueous Humor↗

PubMed2006

Cytomegalovirus in aqueous humor from an eye with corneal endotheliitis.

PURPOSE: To report cytomegalovirus (CMV) DNA in aqueous humor from a patient with unilateral corneal endotheliitis. DESIGN: Case report. METHODS: A 51-year-old man presented with unilateral corneal endotheliitis with linear keratic precipitates and coin-shaped lesions. Tear and aqueous humor samples were subjected to polymerase chain reaction to look for DNA from herpes simplex virus (HSV), varicella zoster virus (VZV), and CMV. RESULTS: Aqueous humor from the diseased eye contained DNA from CMV but not HSV or VZV. Its specificity was confirmed by Southern blot tests. Intravenous ganciclovir treatment resulted in the localization of his corneal edema and the reduction in keratic precipitates. There was severe destruction of corneal endothelial cells. CMV DNA was not detected in tears or control samples. CONCLUSIONS: In this healthy man with corneal endotheliitis, we detected CMV DNA in aqueous humor from the affected eye, but not HSV or VZV. This suggests that CMV may cause corneal endotheliitis in patients without immunodeficiency.

Acyclovir↗

PubMed1998

Substance P in proliferative vitreoretinopathy: the significance of aqueous humor levels for evolution of the disease.

PURPOSE: We detected aqueous humor levels of substance P in patients with various grades of proliferative vitreoretinopathy and with uncomplicated rhegmatogenous retinal detachment. To evaluate the significance of the concentration of substance P at the time of surgery for retinal detachment for subsequent development of proliferative vitreoretinopathy, the latter patients also underwent fundoscopic control examination. METHODS: Using a highly specific and sensitive radioimmunoassay, the content of substance P in fresh samples of aqueous humor obtained by paracentesis was determined both in cataract controls and in patients with uncomplicated rhegmatogenous retinal detachment and with various grades of proliferative vitreoretinopathy. Retinal detachment patients underwent fundoscopic control examination 6 months after surgical reattachment. RESULTS: The mean concentration of substance P in cataract controls was 40.3 (+22.4) fmol/mg protein, in the retinal detachment group 61.9 (+/-13.9) fmol/mg protein and in proliferative vitreoretinopathy 335.2 (+/-24.8) fmol/mg protein, but no correlation between levels of the peptide and various grades of the disease was observed. Already at surgery for retinal detachment three in four patients who developed proliferative vitreoretinopathy presented with levels of substance P in the range of the disease. CONCLUSION: The concentration of substance P in aqueous humor is significantly high in patients with proliferative vitreoretinopathy in whom surgery is indicated. Furthermore, elevation of the peptide in retinal detachment that originates most obviously from a neurogenic mechanism may indicate initiation of processes associated with proliferative vitreoretinopathy, thus representing an indicator of significant risk for evolution of the disease at a very early time.

Adult↗

PubMed1989

Detection of glycated polypeptides in human aqueous humor by lectin-binding analysis.

The proteins from 30 samples of normal human aqueous humor were separated into major fractions by sodium dodecyl-sulfate polyacrylamide gel electrophoresis, transferred to nitrocellulose, and probed with lectins to characterize the glycated polypeptides. The lectins used were derived from Canavalia ensiformis (concanavalin-A), Phaseolus vulgaris (erythroagglutinin), Arachis hypogaea (peanut agglutinin), and Ulex europaeus agglutinin-I. Using this microanalytical technique, the glycated polypeptides in the aqueous humor were separated into nine major fractions with apparent molecular weights of 17, 41, 50, 55, 61, 77, 80, 120 and 151 kDa. The predominant oligosaccharides detected on these fractions were complex chains usually with sialic acid residues. The possible roles of the glycated polypeptides in the aqueous humor in health and disease are discussed. Our investigation of these molecules in human aqueous humor provides baseline data for a rapid diagnostic analysis of microsamples of this fluid obtained from diseased eyes.

Aged↗

PubMedDate not supplied

PCR with the aqueous humor, blood leukocytes and vitreous of patients affected by cytomegalovirus retinitis and immune recovery uveitis.

PURPOSE: To detect the cytomegalovirus (CMV) genome by PCR in the aqueous humor, blood leukocytes and vitreous of patients affected by retinitis and immune recovery uveitis (IRU). METHODS: A PCR for CMV genome detection was carried out with the aqueous humor, vitreous and blood leukocytes of 54 patients with retinitis, including 25 HIV-infected patients presenting CMV retinitis in different stages (active lesion 6 cases, healed lesion 14 cases and IRU 5 cases), and 29 non-HIV-infected patients (retinitis unrelated to CMV) as negative controls. RESULTS: The CMV genome was detected in the vitreous, aqueous humor and blood leukocytes of 3 out of 6 HIV-infected patients, presenting active lesions in the retina. No CMV genome was detected in the vitreous, aqueous humor and blood leukocytes of the 5 HIV-infected patients presenting IRU. CONCLUSIONS: CMV genome detection by PCR in aqueous humor could be used as a specific and highly predictive technique for confirmation of this infection in the retina. The absence of CMV, based on the results of PCR done in clinical samples of the 5 IRU cases, does not confirm the hypothesis of a viral replication in the vitreous body and aqueous humor of these patients.

Adult↗

PubMed1996

[An experimental study of tumor necrosis factor (TNF) and interleukin-1 (IL-1) in aqueous humor after intraocular lens implantation].

OBJECTIVE: The tumor necrosis factor (TNF) and interleukin-1 (IL-1) levels in aqueous humor after intraocular lens (IOL) implantation were studied in rabbit eyes and their effects on post-operative anterior ocular inflammation were discussed. METHODS: 27 adult pigmented rabbits were divided into three groups: (1) Lens extraction and intraocular lens (IOL) implantation in the capsular bag. (2) Simple extracapsular lens extraction, and (3) normal control group without surgical intervention. Aqueous humor samples were aspirated on days 1, 3, 7 and 14 postoperatively. A modified double-antibody indirect sandwich ELISA was used to detect for the presence of TNF. MTT colorimetry was used to detect for the presence of IL-1. The data were analysed statistically. RESULTS: TNF and IL-1 levels in the aqueous humor were significantly higher (P < 0.05) at 1, 3, 7, and 14 days postoperatively in IOL implanted group than that in the control group, and TNF levels in aqueous humor at 3, 7 and 14 days postoperatively and IL-1 levels at 1 and 3 days postoperatively were significantly higher (P < 0.05) in IOL implanted group than that in simple extracapsular lens extraction group (P < 0.05). In the postoperative 7-14 days, the TNF and in the 3 to 14 days the IL-1 in the aqueous humor reached their maximum levels in IOL implantation group. CONCLUSIONS: It is reasonable to consider that the increases of TNF and IL-1 levels may play critical roles in the anterior ocular inflammation response after IOL implantation.

Animals↗

PubMed1990

[Local anesthetics in the aqueous humor in local anesthesia of the eye].

Local anesthetics injected retrobulbarly are detectable in the aqueous humor. From 40 patients who received a total dose of 140 mg lidocaine, 15 mg bupivacaine, and 30 mg etidocaine, samples of aqueous humor were taken between 30 and 90 minutes after administration (average 57 minutes). The mean lidocaine concentration was 1.02 micrograms/ml, that of bupivacaine 0.075 micrograms/ml. Etidocaine, used only for facial nerve block in front of the ear, could not be detected in the aqueous humor. All three substances were found in the central venous blood. It therefore appears unlikely that any of them are transported via the blood-aqueous barrier, whether actively or passively. Local anesthetics can inhibit corneal cell proliferation and result in lens opacification when administered into the conjunctival sac. It may be that local anesthetics detected in the aqueous humor have similar effects resulting from contact with the cornea and lens.

Aged↗

PubMed1995

Collagen metabolism in human aqueous humor from primary open-angle glaucoma. Decreased degradation and increased biosynthesis play a role in its pathogenesis.

OBJECTIVE: To explore the influence of aqueous humor from patients with glaucoma on collagen turnover. METHODS: The aqueous humor of patients with primary open-angle glaucoma (POAG), chronic angle-closure glaucoma, congenital glaucoma, neovascular glaucoma, and senile cataract (control group) was analyzed for its capacity to induce fibroblast proliferation, collagen synthesis, collagenolytic activity, and production of tissue inhibitor of metalloproteinase-1. All data were analyzed using the Mann-Whitney U test. RESULTS: Aqueous humor derived from patients with POAG induced a significant decrease of functional collagenase activity (mean +/- SE, 9.12 +/- 1.33 microgram of degraded collagen per milligram of incubated protein vs 20.94 +/- 4.14 micrograms from the control group, P < .05). The enzymatic activity in the other types of glaucoma was similar to that of controls. The POAG samples had a significantly higher concentration of tissue inhibitor of metalloproteinase-1 (mean +/- SE, 3.11 +/- 0.58 vs 0.91 +/- 0.13 micrograms/mL from controls; P < .05). The amount of immunoreactive tissue inhibitor of metalloproteinase-1 found in the other three groups was not significantly different from the control. Aqueous humor stimulated fibroblast proliferation in all cases, but significant differences were not observed between the POAG samples (mean +/- SE, 20,285 +/- 4642 cpm/mg of incubated protein) and the control group samples (26,550 +/- 3688 cpm/mg of incubated protein). Primary open-angle glaucoma fluids increased collagen synthesis significantly compared with the control group (mean +/- SD, 3352 +/- 630 vs 985 +/- 285, P < .05), and the other groups. CONCLUSIONS: An increase of collagen synthesis and a decrease of collagen degradation may contribute to an excessive deposit of collagen with loss of the trabecular cells during the development of POAG, and aqueous humor must be considered as a microenvironment that affects the metabolism or function of the trabecular meshwork or both.

Adult↗

PubMed1987

Chemotactic activity in aqueous humor from patients with anterior uveitis.

Anterior uveitis, inflammation of the iris or ciliary body of the eye, may be associated with a variety of systemic diseases. Although a leukocytic infiltrate is characteristic of anterior uveitis, few studies have sought to detect factors in aqueous humor that could attract neutrophils or monocytes into the anterior chamber. Using modified Boyden chambers, we found that a 5% concentration of aqueous humor from patients with anterior uveal inflammation induced monocyte movement comparable to optimal or near-optimal concentrations of C (complement)5a or platelet-derived growth factor. Aqueous humor from patients with anterior uveitis induced significantly more monocyte migration than did aqueous humor from two sets of controls (either patients undergoing cataract extraction or patients with posterior uveitis). "Checkerboard" or gradient analysis indicated that a majority of inflammatory disease samples induced monocyte chemotaxis (directed migration) while the control aqueous humor consistently induced chemokinesis (stimulated random migration) (P less than 0.02). Despite their ability to induce monocyte migration, samples tended to induce minimal neutrophil migration with the exception of aqueous humor that was obtained from one patient with acute anterior disease. This sample induced marked chemokinesis. Identification of chemotactic activity may clarify the pathogenesis of uveitis and the characterization of leukocyte migration factors in aqueous humor may help define subsets of anterior uveal inflammation.

Aqueous Humor↗

PubMedDate not supplied

Lactate levels in the rabbit cornea and aqueous humor subsequent to non-gas permeable contact lens wear.

The validity of using the aqueous humor lactate concentration as an indicator of corneal lactate production was tested. For this purpose, ten rabbits wore non-gas permeable contact lenses on one eye for 12 hours. Aqueous humor and corneal extracts were assayed for lactate by means of an enzymatic technique. The contact lens wear caused a limited increment in the corneal lactate concentration, but no change was recorded in the aqueous humor. We therefore conclude that the corneal lactate production has a negligible effect on the lactate concentration in aqueous humor. However, significant individual variations in lactate levels were recorded in the present study, as in earlier ones. Insufficient specificity in the currently used techniques for lactic acid concentration determination may in part explain this.

Animals↗

PubMed1998

The effect of aqueous humor suppressants on intravitreal gas bubble duration in rabbits.

PURPOSE: To evaluate the effect of topical aqueous humor suppressants on the absorption of intravitreal perfluorocarbon gases. METHODS: Sulfur hexafluoride or perfluoropropane was injected intravitreally in five rabbits. Time to gas disappearance was measured in eyes treated with topical aqueous humor suppressants and in those not treated. RESULTS: The mean time (+/- SD) to disappearance of 0.4 cc of sulfur hexafluoride was 5.6 +/- 0.9 days, which was prolonged by 43% to 8.0 +/- 0.7 days with topical aqueous humor suppressants (P = .009). The mean time (+/- SD) to disappearance of 0.2 cc of perfluoropropane was 18.4 +/- 1.9 days, which was prolonged by 55% to 28.6 +/- 2.7 days with topical aqueous humor suppressants (P = .009). CONCLUSION: Aqueous suppressants prolong sulfur hexafluoride and perfluoropropane intravitreal gas bubble duration in rabbits.

Absorption↗

PubMed1994

Corneal epithelial and aqueous humor acidification during in vivo contact lens wear in rabbits.

PURPOSE: Based on contact lens-induced stromal acidification of the cornea, it has been suggested that the corneal epithelial and endothelial cells also become acidotic during contact lens wear. This alleged acidification may have a role in altered cell appearance and metabolism during contact lens wear. This study investigated the effects of anoxia, carbon dioxide retention, and contact lens gas transmissibility on the epithelial and aqueous humor pH in living rabbits. METHODS: Epithelial intracellular pH (pHi) and aqueous humor pH were fluorophotometrically measured with a pH sensitive-dye (BCECF) during contact lens wear or exposure to various gas mixtures. RESULTS: Polymethylmethacrylate (PMMA) lens wear acidified epithelial cells by preventing CO2 efflux and by inducing hypoxia. Increasing lens oxygen transmissibility decreased epithelial acidification. After initiation of rigid, gas-permeable (RGP) lens wear or CO2-air exposure, pHi dropped transiently and then recovered partially. This recovery of pHi was not observed during anoxia, whether induced by PMMA lens wear or exposure to 100% N2. The aqueous humor also acidified during PMMA lens wear, a phenomenon not observed during RGP lens wear. Changes in aqueous pH were smaller, slower, and delayed when compared to their epithelial counterparts. CONCLUSIONS: Hypoxic contact lens wear acidifies the corneal epithelium and aqueous humor. The aqueous humor pH change indicates a probable endothelial acidification during hypoxic contact lens wear; the pH changes are caused by two separate and additive effects, CO2 retention and hypoxic acidosis. Increases in the oxygen transmissibility of the lens decrease the cellular acidosis, which might minimize cellular complications arising from contact lens wear. We estimate that a lens with an oxygen transmissibility (Dk/L) of 300 x 10(-11) (cm/sec)(ml O2/ml x mm Hg) is needed to prevent epithelial pHi changes in the open eye. In contrast, lenses with Dk/L as low as 18 x 10(-9) (cm/sec)(ml O2/ml x mm Hg) can prevent aqueous humor pH changes.

Acidosis↗

PubMed1998

Polymerase chain reaction for the detection of Toxoplasma gondii within aqueous humor of experimentally-inoculated cats.

The purpose of this study was to determine the temporal appearance of T. gondii in aqueous humor of cats orally inoculated with T. gondii using polymerase chain reaction (PCR) for the detection of the B1 gene. Serum and aqueous humor were collected from five SPF cats prior to oral inoculation with T. gondii and days 7, 14, 21, 28, 42, 84, 140, 147, 154, 161, 168, and 182 after inoculation. Cats were inoculated orally with T. gondii tissue cysts on day 0 and day 140. T. gondii-specific IgM and IgG were measured in serum and aqueous humor from the cats at each sample data. T. gondii B1 gene PCR was performed on all the aqueous humor samples and the amplified DNA was detected by Southern blotting. Chorioretinitis developed in three out of the five cats, but anterior uveitis was not detected. All cats developed T. gondii-specific IgG titers in serum, and had T. gondii-specific IgG C-values > 1 in both eyes at varying times during the study. T. gondii was detected by PCR and Southern blotting in aqueous humor in both eyes of all cats at times varying from days 14-84 after primary inoculation and days 14-42 after challenge inoculation.

Administration, Oral↗