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Results for “Aqueous Humor”

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PubMed1988

Effect of Yag-laser anterior capsulotomy on the biochemical content of aqueous humor.

Elevation of prostaglandins and protein in the aqueous humor is an immediate response to Yag-laser anterior capsulotomy. There was a significant correlation between prostaglandins and thromboxane to the elevation of intraocular pressure. The elevation of protein concentration was proportional to the elevation of prostaglandin F1, but not to thromboxane. The biochemical changes in the aqueous humor were more severe as laser power was increased above 3 mj. While the role of prostaglandins in the elevation of intraocular pressure is uncertain, the present data recommend the selection of laser power below 3 mj to avoid pressure rise instead of inhibition of all prostaglandin synthesis by medication.

Aqueous Humor↗

PubMed1993

Photoreceptor outer segments in the aqueous humor of patients with atopic dermatitis and retinal detachment.

We examined the aqueous humor by electron microscopy of four patients with atopic dermatitis and retinal detachment. All the patients had a moderate number of cells in the aqueous humor. Cataract impaired fundus visualization except for one patient with aphakia. A flat retinal detachment involved a wide area detected by echography. The intraocular pressure in the eyes with retinal detachment demonstrated a marked diurnal fluctuation compared with that of the fellow eye. The aqueous cells consisted predominantly of photoreceptor outer segments. This finding does not support the theory that aqueous cells in atopic dermatitis are of inflammatory origin. Photoreceptor outer segments in aqueous humor are indicative of rhegmatogenous retinal detachment in patients with atopic dermatitis.

Adolescent↗

PubMed2000

Aqueous humor nitric oxide levels in patients with central retinal artery occlusion.

BACKGROUND/PURPOSE: There is increasing evidence suggesting that nitric oxide (NO) is implicated in the pathogenic process of ischemic disease. The purpose of this study was to quantify the aqueous humor NO levels in patients with central retinal artery occlusion (CRAO) and in age-matched controls. METHODS: Aqueous humor specimens were obtained from seven patients who had been diagnosed with CRAO; the sampling was done within 12 to 24 hours of diagnosis. All specimens were obtained by paracentesis, which was performed as a therapeutic intervention. Samples of aqueous humor were also collected from 15 age-matched healthy patients undergoing cataract surgery, to be used as controls. For each sample, we assayed the amount of nitrite, which is the stable metabolite of NO, using the spectrophotometric method based on the Griess reaction. RESULTS: There were detectable levels of nitrite in the aqueous humor from five of seven patients with CRAO (mean level, 0.32 +/- 0.08 micromol/L). The 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 the CRAO group and the controls (P = 0.0008). CONCLUSIONS: Our study shows that patients with CRAO present with elevated levels of NO in the aqueous humor. These findings may provide insight into the role that NO plays in CRAO.

Aged↗

PubMed2007

Aqueous humor penetration of gatifloxacin and moxifloxacin eyedrops given by different methods before cataract surgery.

PURPOSE: To determine whether the penetration into the aqueous humor of 2 new fourth-generation fluoroquinolone antibiotics, gatifloxacin (Zymar) and moxifloxacin (Vigamox) eyedrops, was affected by different methods of administration before cataract surgery. SETTING: Pasqua Hospital, Regina, Saskatchewan, Canada. METHODS: This prospective randomized study comprised 193 patients. The patients were divided into 2 main groups. One group received gatifloxacin eyedrops and the other, moxifloxacin eyedrops. Each group was subdivided into 4 subgroups. All patients received the drops 4 times a day starting 2 days preoperatively. The first subgroup did not receive any more antibiotics. The second subgroup received the antibiotic drops 3 times, starting approximately 2 hours preoperatively. The third subgroup received a wick soaked in a dilating mixture containing the antibiotic. The fourth subgroup received the wick and the antibiotic drops at the time of preparation for surgery. At the beginning of surgery, 0.1 mL of aqueous humor was aspirated, frozen, and sent under ice by courier to the Provincial Laboratory for analysis by high-performance liquid chromatography. RESULTS: The study included 124 women and 69 men. The mean concentrations in the aqueous humor were 0.19, 0.82, 0.22, and 0.30 microg/mL in the 4 gatifloxacin subgroups, respectively, and 0.38, 2.16, 0.88, and 0.97 microg/mL in the 4 moxifloxacin subgroups, respectively. Analysis of variance showed the differences between the 2 antibiotics to be statistically significant. CONCLUSIONS: Moxifloxacin penetrated the aqueous humor better than gatifloxacin regardless of the method of administration. Both antibiotics penetrated the aqueous humor well when given in drop form. They reached and exceeded the minimum inhibitory concentration levels for the most common ocular pathogens causing endophthalmitis. Only moxifloxacin reached these levels when the wick was used.

Adult↗

PubMed1989

Lens crystallin reactive protein in the aqueous humor of cataract patients.

It is well known that soluble protein decreases in the senile cataractous lens. In this report, the possibility of soluble protein leakage through the capsule into the aqueous humor was studied. Aqueous humor from cataractous patients was obtained in the operating room and analyzed by molecular sieve high performance liquid chromatography (HPLC) and electrophoretic immune blotting assay. A whole lens was obtained from a patient with lens luxation. The lens was kept in Tyrode's incubation medium and the protein leakage into the medium was also analyzed by electrophoretic immune blotting assay. beta L-crystallin reactive protein was ascertained in the aqueous humor of senile cataractous patients. Leakage of the beta L-crystallin reactive protein increased in immature and mature cataracts. The present results also demonstrated leakage of lens crystallin from the senile cataractous lens without capsular rupture.

Aqueous Humor↗

PubMed1988

Immunohistochemistry of angiotensin I-converting enzyme in rat eye structures involved in aqueous humor regulation.

Angiotensin-converting enzyme (ACE) was localized by immunohistochemical methods in rat eye structures involved in aqueous humor secretion and reabsorption, i.e., the ciliary processes, the trabeculum, and Schlemm's canal. The three-layer peroxidase-antiperoxidase method was used with light and electron microscopy. In the ciliary processes, ACE was found on the basal plasma membrane of the internal epithelium facing the aqueous humor and on vesicles in its vicinity, whereas neither the external epithelium nor the blood vessels running through the ciliary processes were immunoreactive. A faint ACE immunoreactivity was found on some endothelial cell plasma membranes of both the internal collector channels and Schlemm's canal. These results suggest that the ciliary process internal epithelium could be an important site for the production of angiotensin II and/or the metabolism of bradykinin. In addition, the present investigation provides evidence for ACE involvement in aqueous humor secretion, whereas its involvement in aqueous humor reabsorption may be minor.

Animals↗

PubMedDate not supplied

Flomoxef sodium and levofloxacin concentrations in aqueous humor.

AIMS: We intravenously administered flomoxef sodium (FMOX) 120 minutes before cataract surgery, topically administered levofloxacin (LVFX) into the eyes four times at 30-minute intervals before surgery, and measured the aqueous humor concentrations of these agents to investigate their penetration into the aqueous humor and their efficacy in the prevention of postoperative endophthalmitis. METHODS: Sixty-eight patients who underwent cataract surgery at the Department of Ophthalmology, Yokohama City University School of Medicine, or its affiliate, Kanazawa Hospital, Yokohama, were enrolled in this study. They received one or both of the following: 1.0 g FMOX via a 20-minute intravenous drip and LVFX ophthalmic solution applied four times at 30-minute intervals, both beginning two hours before the operation. Aqueous humor was aspirated from the anterior chamber and assayed for FMOX and LVFX concentrations using high-performance liquid chromatography (HPLC). RESULTS: The mean intraoperative FMOX and LVFX concentrations in the patients' aqueous humor were 1.21 +/- 0.63 microg/ml and 0.69 +/- 0.47 microg/ml, respectively. These concentrations sufficiently exceeded the MIC90 values against Staphylococcus epidermidis, S. aureus, and Propionibacterium acnes. CONCLUSIONS: The FMOX and LVFX concentrations in the aqueous humor sampling were adequate to kill bacteria in vitro. These drugs may have efficacy in the prevention of postoperative endophthalmitis in patients undergoing cataract surgery.

Administration, Topical↗

PubMed1986

Ascorbic acid levels in the aqueous humor of nocturnal and diurnal mammals.

Ascorbic acid concentration is known to be very high in the aqueous humor of humans and most animals. The role it might play in ocular function is a subject of conjecture. Some have proposed that it might protect the eye against light-induced damage. We examined the aqueous humor from 22 species of mammals to determine the range of levels and to see if there was a correlation with behavior. A wide range of ascorbic acid levels in the aqueous humor was found. Most of the animals considered to be diurnal had higher ascorbic acid levels than the nocturnal animals. This would suggest that ascorbic acid in the aqueous humor may play a protective role in those animals who are most exposed to light. Regardless, any theory proposing a role for ascorbic acid in the eye in mammals must take the wide range of ascorbic acid levels into account.

Animals↗

PubMed1997

Photoreceptor outer segments in aqueous humor from dogs with rhegmatogenous retinal detachments.

OBJECTIVE: To determine whether photoreceptor outer segments can be found in aqueous humor from dogs with rhegmatogenous retinal detachment (RRD). DESIGN: Case series. ANIMALS: 4 dogs with unilateral RRD, 2 dogs with bilateral RRD, 1 dog with unilateral non-RRD, and 1 dog with glaucoma without retinal detachment. PROCEDURE: Aqueous humor samples were fixed in 2% glutaraldehyde and examined by means of transmission electron microscopy. RESULTS: Outer segments were found in aqueous humor from 7 of 8 eyes with RRD but were not found in aqueous humor from dogs with non-RRD or glaucoma. CLINICAL IMPLICATIONS: Photoreceptor outer segments may move into the anterior chamber of eyes with RRD.

Animals↗

PubMed1997

Aqueous humor induces transforming growth factor-beta (TGF-beta)-producing regulatory T-cells.

PURPOSE: The intraocular microenvironment is an immune-privileged site where immunogenic inflammation is suppressed. Suppression of immunogenic inflammation has been associated with immunosuppressive factors found in aqueous humor produced by ocular tissues. To further understand the mechanisms suppressing immunogenic inflammation in the eye, we have examined the production of lymphokines by primed T-cells activated in the presence of aqueous humor. METHODS: Enriched in vivo primed T-cells were T-cell receptor-stimulated in the presence of fresh aqueous humor. The culture supernatant was assayed for IFN-gamma and IL-4 by sandwich ELISA. TGF-beta production by T-cells stimulated in the presence of aqueous humor was assayed by a TGF-beta bioassay of the culture supernatant and by quantitative RT-PCR for TGF-beta 1 mRNA expression. Aqueous humor-treated T-cells were assayed for their capacity to suppress IFN-gamma production by stimulated, primed T-cells. RESULTS: Aqueous humor-enhanced proliferation but irreversibly suppressed production of both IFN-gamma and IL-4 by in vitro-activated, in vivo-primed T-cells. Aqueous humor induced in vivo primed T-cells to produce TGF-beta in vitro, and these TGF-beta-producing T-cells suppressed IFN-gamma production by other T-cells activated in co-cultures. CONCLUSIONS: Aqueous humor alters the functional program of TCR-ligand-activated, primed T-cells, converting the cells to TGF-beta-producing regulatory cells.

Animals↗

PubMedDate not supplied

Aqueous humor inhibits epidermal cell antigen-presenting function.

Aqueous humor (AH) is a complex biological fluid containing factors that mediate a number of activities that may contribute to immune privilege in the anterior chamber of the eye. To determine whether AH may inhibit dendritic cell antigen-presenting function, we evaluated the ability of AH to alter the ability of freshly obtained epidermal cell (EC) preparations enriched for Langerhans cells (LC) to present tumor-associated antigens (TAA) derived from the S1509a spindle cell tumor for elicitation of a delayed-type hypersensitivity (DTH) reaction in tumor-immune mice. Fresh EC preparations contain 2-5% LC. Exposure of EC to media containing AH for 2 hours prior to TAA-pulsing and injection into a hind footpad of tumor-immune mice resulted in a dose-dependent decrease in the DTH response. Aqueous humor contains transforming growth factor-beta (TGF beta), primarily TGF beta 2 as determined by specific neutralization of activity in the Mv 1 Lu cell assay. However, exposure of EC to TGF beta 2 in this fashion prior to TAA-pulsing had no effect on the degree of hypersensitivity elicited. Furthermore, preincubation of AH with neutralizing antiserum to TGF beta 2 had no effect on the ability of AH to inhibit LC antigen-presenting function. Mixing of AH-exposed non-TAA-pulsed EC with TAA-pulsed EC not exposed to AH prior to footpad challenge did not diminish the DTH response, suggesting that carryover of AH into the footpad was not responsible for the inhibition observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1999

Adenoviral reporter gene transfer to the human trabecular meshwork does not alter aqueous humor outflow. Relevance for potential gene therapy of glaucoma.

Obstruction of the aqueous humor outflow from the anterior chamber of the eye leads to an elevation of intraocular pressure in glaucoma, the second major cause of blindness worldwide. Our goal is to be able to modulate aqueous humor outflow resistance by gene transfer to the cells of the trabecular meshwork (TM). We have previously shown that adenoviral vectors are able to transfer a reporter gene to the TM of postmortem human donors. However, assessing gene therapy for glaucoma requires models that can monitor changes in aqueous humor outflow facility (C = flow/pressure). In this study we used four replication-deficient adenoviruses in two such perfusion models. In the first model, whole porcine eyes were infected, perfused at constant pressure and flow changes recorded for 5 h. In the second one, anterior segments from human eyes were infected, perfused at constant flow and pressure changes recorded for 3 days. A single dose of 10(8) adenovirus plaque forming units (pfu) causes a reduction in C while single doses of 10(7), 10(6) and 10(5) p.f.u. do not affect outflow facility and retain positive gene transfer. These findings indicate that adenovirus, at effective doses, could become useful vectors for gene therapy of glaucoma.

Adenoviridae↗

PubMed1996

[Regulation of glutathione level in venous plasma and aqueous humor in cataracta senilis provecta].

UNLABELLED: Glutathione is a major component of the mechanisms protecting the eye against oxidants. To analyse the functional status and the regulation of the glutathione system in the eyes of patients with advanced cataract, glutathione concentrations were quantified in venous plasma and aqueous humor. METHODS: In all, 42 patients with advanced cataract (29 women, 13 men; mean age (+/- SEM) 70 +/- 2 years; vision < or = 0.3) were evaluated. Aqueous humour and venous plasma were obtained at the beginning of cataract surgery. RESULTS: Levels of total glutathione [reduced (GSH) + oxidized glutathione (GSSG)] in plasma were 2.34 +/- 0.23 microM. There was 2.08 +/- 0.15 microM in the reduced form and 0.27 +/- 0.17 microM oxidized glutathione, which means that 94.7 +/- 2.1% of the total glutathione was GSH, the form fully functional as an antioxidant. Levels of total glutathione in the aqueous humor were 1.2 +/- 0.16 microM, i.e. 54.5 +/- 4.8% of plasma levels. Surprisingly, the percentage of GSSG in aqueous humor (0.24 +/- 0.07 microM, 31 +/- 10.5% of the total glutathione) was much higher than that in plasma (P < 0.001). The correlation between glutathione concentrations in plasma and aqueous humor was on the borderline of significance (rs = 0.32, P < 0.04). CONCLUSION: The proportion of oxidized glutathione is higher in aqueous humor than in plasma of patients with advanced senile cataracts, indicating increased oxidant stress in the eye. Further, the regulation of the glutathione system in the eye, at least in aqueous humor, is dependent on plasma glutathione levels. This correlation reflects the importance of sufficient glutathione levels in venous plasma and suggests the possibility of modulating the glutathione system in the eye via manipulation of plasma glutathione levels.

Aged↗

PubMed1989

Chemotactic activity of aqueous humor. A cause of failure of trabeculectomies?

The chemoattractant activity for ocular fibroblasts of the aqueous humor of patients undergoing glaucoma surgery was evaluated in 48-well microchemotaxis chambers and compared with control specimens from patients undergoing cataract extractions. All specimens were chemoattractant, but those from patients who had previously undergone glaucoma surgery that had failed were of significantly greater activity than the controls'. This chemoattractant activity is primarily chemotactic. It consists of heat-stable and heat-labile components. The predisposition of a patient to sustain failed glaucoma drainage surgery may be related to the chemoattractant activity of his aqueous humor, since strongly chemoattractant aqueous humor may encourage fibrosis at the operation site.

Animals↗

PubMed2004

Role of lysophospholipid growth factors in the modulation of aqueous humor outflow facility.

PURPOSE: To investigate the role of lysophospholipid growth factors in the regulation of aqueous humor outflow in the trabecular meshwork (TM). METHODS: The expression profile of the endothelial differentiation gene (Edg) family of G-protein coupled receptors was determined by RT-PCR of human TM (HTM) cell-derived total RNA and by PCR amplification of HTM cell-derived and tissue-derived cDNA libraries. The effects of lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) on actin cytoskeleton and focal adhesions and on myosin light-chain (MLC) phosphorylation in HTM cells were evaluated by immunofluorescence microscopy and Western blot analysis, respectively. Activation of Rho GTPase in HTM cells was quantified by "pull-down" assays. Mobilization of intracellular calcium in HTM cells was determined using spectrofluorometric digital-imaging microscopy. The effects of LPA and S1P on aqueous humor outflow facility were evaluated by perfusion of enucleated porcine eyes. RESULTS: Each of the receptor isoforms Edg1, -2, -3, and -4 was readily detectable in three of four HTM cell-derived libraries, whereas Edg2 was detectable in the HTM tissue library. LPA (20 microM) and S1P (1 microM) stimulated actin stress fiber and focal adhesion formation, increased MLC phosphorylation, and induced marked activation of Rho GTPase in HTM cells. Both LPA (20 microM) and S1P (10 microM) also stimulated increases in intracellular calcium concentration in HTM cells. LPA- and S1P-induced effects on MLC phosphorylation in HTM cells were markedly inhibited by pretreatment with the Rho kinase-specific inhibitor Y-27632 (5 microM). Perfusion of LPA (50 microM) and S1P (5 microM) in enucleated porcine eyes produced a significant decrease in aqueous humor outflow facility from baseline of 37% (n = 6) and 31% (n = 5), respectively. CONCLUSIONS: These studies demonstrate that LPA and S1P, the physiological agonists of Edg receptors, decrease outflow facility in perfused porcine eyes in association with increased MLC phosphorylation and Rho guanosine triphosphatase (GTPase) activation. These data provide evidence for a novel mechanism for negative regulation of outflow facility, which may contribute to overall physiological homeostasis of aqueous humor outflow facility.

Actins↗

PubMedDate not supplied

Malondialdehyde and antioxidant enzyme levels in the aqueous humor of rabbits in endotoxin-induced uveitis.

PURPOSE: To investigate the role of oxidative stress in endotoxin-induced uveitis. METHODS: Lipopolysaccharide was injected intravitreally into the right eyes of rabbits. Sterile saline was injected intravitreally into the left eyes as a control. Inflammation was assessed according to clinical score, aqueous humor cell count, and protein levels. Malondialdehyde, superoxide dismutase, glutathione peroxidase, catalase, and nitrite levels were measured in the aqueous humor. RESULTS: The clinical grade (p < 0.01), inflammatory cell count (p < 0.001), and protein content (p < 0.001) were significantly higher in the aqueous humor of eyes with uveitis than in that of controls. Malondialdehyde (p < 0.01) and nitrite (p < 0.001) levels in the aqueous humor of eyes with uveitis were significantly higher than in the control group. Superoxide dismutase (p < 0.001), glutathione peroxidase (p < 0.001), and catalase (p < 0.001) levels were significantly lower in the aqueous humor of eyes with uveitis than in that of the controls. CONCLUSIONS: Oxygen free radicals may be implicated as a mediator of inflammation in endotoxin-induced uveitis. The increase in free radicals in the aqueous humor may play a role in the pathogenesis of endotoxin-induced uveitis.

Animals↗

PubMed1993

An improved technique for the diagnosis of viral retinitis from samples of aqueous humor and vitreous.

We applied the technique of DNA amplification with the polymerase chain reaction to nine aqueous humor and five vitreous samples from HIV-1-infected patients with clinically diagnosed cytomegalovirus retinitis. For the amplification, recently published primers specific for herpes simplex virus (HSV), varicella zoster virus (VZV) and cytomegalovirus (CMV-1) were used. Additionally, a newly developed primer pair specific for the main immediately early gene of CMV (CMV-2) was selected and compared with the published one. All primers were tested on noninfected and HSV-, VZV- and CMV-infected human fibroblast cell culture supernatant, thereby excluding cross-reactivity of the chosen primers. In none of 13 aqueous humor and six vitreous samples of healthy controls was any viral DNA amplified. Using the CMV-1 primers, we detected CMV DNA in five of nine aqueous humor and three of five vitreous samples amplifying a DNA fragment 435 base pairs in length. With the CMV-2 primers, we detected a CMV DNA fragment with a length of 110 base pairs in eight of nine aqueous humor and in four of five vitreous samples. Additionally, CMV DNA was found in three of nine urine and two of nine saliva specimens. Both CMV and HSV DNA were amplified in one aqueous sample. Varicella DNA was not detected in any of the specimens. Thus, the polymerase chain reaction is more sensitive than other comparable diagnostic tests and may provide an alternative to conventional virus isolation and in situ hybridization techniques for the laboratory diagnosis of viral ocular disease.

Acquired Immunodeficiency Syndrome↗

PubMedDate not supplied

Effect of disinsertion of rectus eye muscles on aqueous humor composition in rabbits.

BACKGROUND AND OBJECTIVES: To evaluate aqueous humor composition and biochemical analysis in a rabbit model for anterior segment ischemia. MATERIALS AND METHODS: Six rabbits underwent bilateral disinsertion of the four rectus eye muscles. One day later, aqueous humor (0.1 to 0.2 mL) was withdrawn from the anterior chamber and the concentrations of electrolytes, glucose, and lactate were determined. Similar assessments were performed in 8 eyes of 4 control rabbits that were not operated on. RESULTS: Sodium and calcium concentrations (mean +/- standard deviation) were significantly higher in the study group than in the control group (142 +/- 2.9 vs 138 +/- 2 mmol/L, P = .002, and 1.4 +/- 0.1 vs 1.3 +/- 0 mmol/L, P = .005, respectively). Potassium concentrations were significantly lower in the study group than in the control group (4.1 +/- 0.5 vs 4.5 +/- 0.1 mmol/L; P = .02). The mean glucose level in the study group was 108.4 mg/dL, which is comparable to the published normal value of 108 mg/dL, and the mean lactate level was 124 mg/dL, which is significantly higher than the published normal value of 78 mg/dL (P = .001). CONCLUSIONS: Bilateral disinsertion of the four rectus muscles in rabbits resulted in a breakdown of the blood-aqueous barrier, as reflected and measured by an electrolyte imbalance. These experimental results may be useful in the future in searching for methods of manipulating the ischemic response. There is currently no indication to perform anterior chamber taps in humans for that purpose.

Animals↗