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At least 1,117 records · Page 62Linked to original sources
PubMed1990

[In vivo examination of aqueous humor for cells and protein in clinically silent anterior uveitis before surgical interventions].

The laser flare cell meter is a new device for measuring flare and cells in the anterior chamber. In 100 eyes we used this device to measure flare and cell counts. We found that eyes with former uveitis and no clinical signs of acute or earlier uveitis have more flare and more cells in the aqueous humor. This is important for IOL implantation and follow-up studies to determine the best way to perform eye surgery.

Aqueous Humor↗
PubMed2006

Pharmacokinetics of timolol in aqueous humor sampled by microdialysis after topical administration of thermosetting gels.

In order to develop a thermosetting gel-based formulation, the ocular pharmacokinetics of timolol was studied utilizing microdialysis sampling technique after topical administration. A linear microdialysis probe was characterized and implanted in the anterior chamber of a rabbit. Dialysate samples collected from the aqueous humor (AH) were directly injected into the HPLC system without any pre-treatment and no interference was observed in the blank sample. The measured in vitro recovery of the probe was 57.67%; however, the in vivo recovery significantly decreased to 16.78% when assessed by the retrodialysis method, which was used to calculate the timolol concentration in AH. Although in the initial 15 min the drug concentrations in AH were comparable to that of the timolol solution, increased Cmax and significantly improved ocular bioavailability were obtained for the gel. When sodium deoxycholate (DC) was incorporated in the gel as a penetration enhancer, a 2-fold increment in the ocular bioavailability was achieved with an increased Cmax and significantly suspended Tmax. The results demonstrated that microdialysis coupled to HPLC is a powerful tool to investigate the ocular pharmacokinetic, and hence facilitates the design of ophthalmic formulations.

Administration, Topical↗
PubMed1979

Toxocara-specific antibody in the serum and aqueous humor of a patient with presumed ocular and visceral toxocariasis.

Rarely have concurrent ocular and systemic toxocariasis been reported in the literature. We describe a patient with serologically proven visceral toxocariasis who had a granulomatous lesion in the iris, small rod-like lesions in the retina, and in whom Toxocara-specific antibodies were also demonstrated in the aqueous humor. Two older siblings of this patient also had demonstrable serum antibody to Toxocara. The ocular manifestations resolved rapidly with corticosteroid and thiabendazole therapy and the initial leucocytosis, hepatomegaly, and elevated IgM level were normal at 3.5 months. These changes might be attributed to either the thiabendazole and prednisone therapy or to the natural history of this disease.

Antibodies↗
PubMed1979

Sickled erythrocytes, hyphema, and secondary glaucoma: V. The effect of vitamin C on erythrocyte sickling in aqueous humor.

In vivo incubations of Hgb SC erythrocytes showed significantly more sickling in anterior chambers characterized by high concentrations of ascorbic acid than in anterior chambers with low concentrations of ascorbic acid (normal guinea pigs compared with scorbutic guinea pigs and normal guinea pigs compared with normal rats). Low concentrations of ascorbic acid, however, did not completely eliminate intracameral sickling. Because acetazolamide raises the concentration of aqueous humor ascorbate, it should be used with considerable discretion when treating hyphema and secondary glaucoma caused by sickle cells. Methazolamide may be more desirable.

Acetazolamide↗
PubMed1981

Beta adrenergic effects on ciliary epithelial permeability, aqueous humor formation and pseudofacility in the normal and sympathectomized rabbit eye.

Relatively selective beta 1- and beta 2-adrenergic agonists (tazolol and terbutaline) and antagonists (metoprolol and butoxamine) were topically applied to albino rabbit eyes and to isolated ciliary epithelium. The beta 2-agonist, terbutaline, was the most effective agent in reducing intraocular pressure although all compounds induced changes in aqueous humor formation rate and pseudofacility. The effects on the isolated ciliary epithelium were determined on tissues derived from both normal and superior cervical ganglionectomized eyes. The beta 1- and beta 2-agonists as well as the beta 1-antagonist induced large permeability increases while the beta 2-antagonist induced a small permeability increase in normal tissues. In ganglionectomized tissues the beta 1-antagonist effect was decreased and the beta 2-antagonist effect enhanced while the agonist effects were almost unchanged. The results show that both beta 1- and beta 2-receptors exist in the ciliary epithelium and that stimulation of either receptor leads to an increase in fluid permeability and alterations in aqueous dynamics.

Adrenergic beta-Agonists↗
PubMed1977

The effect of hyperthermia on aqueous humor dynamics in rabbits.

Hyperthermia increased intraocular pressure (Po) by approximately 5 mm Hg in rabbit eyes. This increase was not associated with changes in plasma osmolarity, blood lactate, or pH. Episcleral venous pressure (Pv) decreased from a baseline of 11 +/- 1 mm Hg(mean +/- SEM) to 8 +/- 1 mm Hg after one hour of hyperthermia. Outflow facility (c) as measured by tonography remained unchanged. Aqueous humor flow [c(Po - Pv)] as estimated by tonography increased by about 126%. The elevation of intraocular pressure was not prevented by aspirin pretreatment nor altered by unilateral optic nerve transection.

Animals↗
PubMed1988

[Diagnosis of ocular toxoplasmosis by the ELISA method applied to the determination of immunoglobulins of the aqueous humor].

The toxoplasmosic origin of focal chorioretinitis can be detected on the basis of certain clinical signs in the fundus. However, this must be biologically confirmed by studying the local production of specific antibodies. For that purpose, the rate of intraocular specific Immunoglobulins is compared to the serum rate. The ELISA method is well adapted to quantitative determination of microamounts in aqueous humors. The authors report a study of 103 patients of whom, 28 were suffering from uveitis, and have studied the correlation between clinical lesions and results of the ELISA test. There was no false positive in the first group reference series, and in the positive cases there was a very high correlation with the clinical indicators.

Adolescent↗
PubMedDate not supplied

Elevated nitric oxide level in aqueous humor of AIDS patients with cytomegalovirus retinitis.

Human cytomegalovirus (HCMV) retinitis is the most common ocular opportunistic infection in AIDS. It often leads to blindness if left untreated. The questions as to how HCMV infection causes retinal immunopathogenesis and visual destruction in AIDS patients have not been completely established. Here we reported that the nitric oxide (NO) levels in aqueous humor samples in 10 AIDS patients with CMV retinitis (104.3 +/- 27.1 microM) were higher than the levels in 7 AIDS patients without CMV retinitis (36.1 +/- 10.4 micro M; p < 0.001). After ganciclovir treatment, the NO level in the vitreous body of 5 patients declined dramatically (53.4 +/- 11.8 micro M). By using immunohistochemistry assay, we found that the aggregates of macrophages infiltrated in the CMV-infected retina of 4 AIDS patients. Moreover, the expression of inducible-form NO synthase was detected in the infected retina of these patients. These results suggest that NO production in the eye may play a fundamental role in the immunopathogenesis of AIDS patients with CMV retinitis.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Bubble formation of aqueous humor and lens opacity during chamber flight.

A transparent miniature decompression chamber was placed on the stage of a large-working zoom-stereo microscope so that the effect of decompression on the frog eye could be microscopically observed and photographed. It was found that chamber flight at a simulated altitude of 66,000 ft (20,117 m) or more caused bubble formation in aqueous humor and lens opacities in some of the experimental animals. On return to ground level, the bubbles either decreased in size or completely disappeared. The cataract could also regress after recompression to 1 atm. Such lens opacities may be termed altitude cataract, instead of asphyxial or anoxic cataract.

Aerospace Medicine↗
PubMed1995

Vitreous and aqueous humors contain a latent proteinase activity that abolishes IGF binding to specific IGF binding proteins.

Several distinct insulin-like growth factor binding proteins (IGFBPs) are present in tissues and fluids of the developing and adult eye. However, the mechanism(s) involved in the regulation of ocular IGFBP levels is unknown. We have now identified an endogenous factor in vitreous and aqueous humors that, when activated by sodium dodecyl sulfate (SDS), abolishes the capacity of specific low molecular weight IGFBPs (i.e. 24-30 kDa) to bind IGF as assessed by western ligand blotting. In contrast, IGF binding to the 46 and 32 kDa IGFBPs (IGFBP-3 and IGFBP-2 respectively) is not affected by the SDS-activated inhibitory factor (IF). Maximal activation of the IF occurs at an SDS concentration of approximately 0.015%. Incubations in the presence of the serine-proteinase inhibitor aprotinin result in marked inhibition of IF activity. Preliminary characterization by ultrafiltration suggests that the IF is large (< 100 kDa) and/or that it is present in a complex. The finding of a factor, most likely a serine proteinase, that specifically abolishes IGF binding to low molecular weight IGFBPs suggests a mechanism for regulating the levels of these IGFBPs and thus the functional activities of IGFs in ocular fluids under normal and/or pathological conditions.

Animals↗
PubMed1976

Demonstration of macrophage chemotactic factors in the aqueous humor during experimental immunogenic uveitis in rabbits.

Factors in the queous humor capable of increasing the random migration and chemotaxis of monocytes were demonstrated during experimental uveitis in the rabbit. Injection of endotoxin-free human serum albumin into the vitreous produced a severe inflammation detectable after 7 days and maximal between 12 to 21 days. Aqueous humor was measured for chemotactic activity with a modified Boyden chamber, which permitted the use of volumes of less than 0.025 ml. Chematactic activity was measurable during the primary inflammation and remained elevated for a short period of time after clinical inflammation and anterior chamber cellular reaction had decreased. A severe reinduction uveitis could be initiated by the intravenous injection of human serum albumin after day 30. Chemotactic factors could be measured at high titers by 8 h after this intravenous challenge.

Animals↗