[Study of aqueous humor dynamic--aqueous humor fluorophotometry and fluorescein concentration curve of aqueous humor of the normal human eye (author's transl)].
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Adolescent↗
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[Study of normal aqueous humor and aqueous humor in cases of glaucoma, and vitreous humor, by immunoelectrophoresis].
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Aqueous Humor↗
Factors affecting ascorbate oxidation in aqueous humor.
Aqueous humor from human glaucomatous eyes was divided into two groups. Group I aqueous humor contains a negligible amount of ascorbate, while group II contains ascorbate. Group I aqueous humor stimulates ascorbate oxidation. This oxidative effect is inhibited by the addition of EDTA, indicating the presence of metallic ions. The amount of copper determined by atomic spectrophotometry in these samples was 1.54 micrograms/ml. On the contrary, group II aqueous humor protects against ascorbate oxidation. The small amount of albumin present in these samples accounts for part of this protective effect.
Aqueous Humor↗
[Alpha-1-antitrypsin, ceruloplasmin and secretory-IgA in human aqueous humor].
Aqueous humor alpha-1-antitrypsin and ceruloplasmin concentration wre determined by immunochemical methods. The absence of secretory IgA shows that aqueous humor is mainly a filtration product of serum.
Adolescent↗
Protein analysis of monkey aqueous humor.
Aqueous humor from individual eyes of young monkeys (Macaca mulatta) was analyzed by gel exclusion chromatography, and one- and two-dimensional gel electrophoresis. The data indicated that in young normal monkey the main peak of protein eluting from gel exclusion columns was observed around 80,000 daltons. There was a small amount of heavy molecular weight material eluting from these columns with an apparent molecular size of greater than 500,000 daltons, but very little material smaller than 40,000 daltons. By one- and two-dimensional gel electrophoresis, the major polypeptide components in the monkey aqueous were similar to those reported for the human aqueous with polypeptides at around 170, 130, 110, 80, 67, 60, 42, 34, 28, 25, 22, 16, and 14 kilodaltons (kD). The monkey aqueous humor also contains the protease inhibitor cystatin.
Animals↗
Isolation and characterization of fibronectin from bovine aqueous humor.
Aqueous humor collected from freshly enucleated bovine eyes was passed over a gelatin affinity column, and bound material was eluted with 4M urea. When fractionated by sodium dodecyl sulfate electrophoresis, the eluted material co-migrated with human plasma fibronectin and protein standards of approximately 220,000 daltons. Amino acid analyses demonstrated a composition similar to that of human plasma fibronectin and fibronectin synthesized by cultured cells. The concentration of fibronectin in aqueous humor is approximately 100 times less than in human plasma.
Amino Acids↗
Catecholamines in human aqueous humor.
Aqueous humor catecholamine levels were measured in 14 patients admitted to hospital for cataract or glaucoma surgery. Norepinephrine was detected in all patients. Epinephrine was detected in one patient who had received a preoperative retrobulbar injection of epinephrine. Dopamine was not detected in any patients. The highest level of norepinephrine was detected in cataract patients with normal intraocular pressures (mean = 7.18 nmol/l).
Aged↗
Ocular irritation leads to the appearance of proteolytic activity in the aqueous humor.
Aqueous humor (AH) collected from healthy eyes of man and rabbit was analysed for proteolytic activity using a casein-agar assay. Normal AH collected during surgery or rabbit AH aspirated before ocular irritation contained no caseinolytic activity. In rabbits, mechanical irritation of the iris and subconjunctival as well as intracameral injection of capsaicin led to ocular irritative response. AH samples collected after such manipulation contained a considerable caseinolytic activity. On the other hand, anterior chamber puncture alone did not seem to induce elevation of caseinolytic activity in AH. The clinical significance of this phenomenon and the mechanisms behind it are discussed.
Animals↗
Phosphorylation of small molecular weight polypeptides in the iris-ciliary complex, aqueous humor and vitreous humor.
The polypeptides of vitreous humor, aqueous humor and iris-ciliary complex cells of eyes were phosphorylated with [gamma-32P]ATP without exogenous protein kinase. Phosphorylated polypeptides were analyzed by sodium dodecyl sulfate gel electrophoresis and autoradiography. The phosphorylated polypeptides of rabbit vitreous humor showed many high molecular weight prominent bands, but no detectable phosphoproteins were found in the 12 kDa or lower range. Bovine vitreous humor has predominantly acidic polypeptides and some of them are below 20 kDa. Rabbit and bovine iris-ciliary complex and rabbit aqueous humor showed a prominent common 4 kDa phosphopolypeptide which could also be synthesized by cloned populations of cells from the bovine iris and the rabbit iris-ciliary body. It is possible that the 4 kDa phosphopolypeptide of the aqueous humor is synthesized by the iris-ciliary complex cells.
Adenosine Triphosphate↗
Comparative study of native proteins in aqueous humor and serum--detection of characteristic aqueous humor proteins.
Native proteins in the aqueous humor and serum from 4 patients with cataract and 2 patients with central artery occlusion were studied using micro two-dimensional isoelectric focusing-gradient gel electrophoresis combined with silver staining. A total of 51 protein spots were detected in the aqueous humor and the standard map of distribution pattern of the native proteins was established. Transferrin, albumin, alpha 2-macroglobulin, ceruloplasmin, haptoglobin, IgA and IgG were identified by an enzyme immunoassay. As a whole, the protein pattern of the aqueous humor is comparable with the pattern of the serum, except for marked quantitative differences. Most aqueous humor components have their corresponding spots found in the serum. However, there are some spots detected only in the aqueous humor but not in the serum. These spots were identified as transferrin. It is already known that the tau fraction (a desialized form of transferrin, absent in serum) is found in an extra band in the electrophoretic patterns of cerebrospinal fluid and vitreous humor. Therefore, the samples were treated with neuraminidase to determine whether or not the different aqueous transferrin spots were the tau fraction. Serum transferrin and certain aqueous transferrin spots (corresponding to serum transferrin in electrophoretic position) were transformed to tau fraction after treatment. However, some other aqueous transferrin spots (tau fraction and unreported transferrin) remained unchanged. This indicated that, in the aqueous humor, there are three kinds of transferrin molecules: ordinary serum transferrin, tau fraction and characteristic aqueous humor transferrin. Soluble proteins in the extracts of ciliary processes, iris, vitreous humor, sensory retina and lens were also studied. The characteristic transferrin pattern seen in the aqueous humor was observed only in the vitreous humor. The ciliary processes and iris revealed an identical transferrin pattern as in the serum. alpha 2-Macroglobulin, that has been thought to be too large to pass the blood-aqueous barrier, was detected in all of the aqueous humor samples. Certain larger serum proteins were observed to have their corresponding spots in the aqueous, whereas certain smaller ones were not found. These findings strongly suggested that the aqueous humor proteins are not a simple ultrafiltrate of the serum. Active transport and/or local synthesis of proteins may play important roles in determining the constitution of the proteins in the aqueous humor.
Adult↗
[Dried drops of aqueous humor and of regenerated aqueous humor in rabbits].
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Animals↗
Potential contribution of epithelial Na+ channel to net secretion of aqueous humor.
The aqueous humor of the eye is secreted by the bilayered ciliary epithelium, consisting of the pigmented (PE) cell layer facing the stroma and the nonpigmented (NPE) cell layer facing the aqueous humor. Cells within each layer and between the two layers are linked by gap junctions, forming a ciliary epithelial syncytium. Unidirectional secretion from the stroma to the aqueous proceeds both through the cells (the transcellular pathway) and between the cells (the paracellular pathway). Net formation of aqueous humor must, however, be the algebraic sum of unidirectional secretion and unidirectional reabsorption from the aqueous humor back into the stoma. The mechanisms potentially underlying reabsorption of aqueous humor by the NPE cells have recently been addressed by studying the regulatory response (RVI) of anisosmotically shrunken NPE cells. The results indicated that epithelial Na+ channels with a high affinity to amiloride likely contribute to reabsorption of solute from the aqueous humor. We have substantiated this possibility by using Northern analysis to identify in human ciliary body RNA a 3.7-kb transcript corresponding to the alpha-subunit of the amiloride-sensitive, alpha beta gamma-ENaC epithelial sodium channel. We have also found that the Na(+)-channel inhibitor benzamil inhibits the RVI without affecting the cell volume of isotonic cell suspensions. This observation supports the hypothesis that the low conductance, highly selective epithelial Na+ channel is activated by shrinkage and contributes to unidirectional reabsorption as aqueous humor. Examples are provided of how the integrative regulation of aqueous humor formation can involve conjugate actions on both unidirectional secretion and reabsorption.
Amiloride↗
Identification of alpha-melanocyte stimulating hormone as a potential immunosuppressive factor in aqueous humor.
The aqueous humor of the eye contains factors that regulate immunological responses within the immunosuppressive ocular microenvironment. Besides TGF-beta, the proteins in the low molecular weight (< 3500 Da) fraction of normal aqueous humor are also immunosuppressive. The low molecular weight fraction of aqueous humor inhibits IFN-gamma production and proliferation of antigen-stimulated lymph node cells. Neuropeptides are one possible family of low molecular weight factors in aqueous humor. Through the utilization of an antigen capturing enzyme-assay, the immunosuppressive neuropeptide alpha-melanocyte stimulating hormone (alpha-MSH) was detected in normal aqueous humor of humans, rabbits, and mice. The mean concentration of alpha-MSH in normal aqueous humor of humans was 20 +/- 3 pM, of rabbits 11 +/- 1 pM, of BALB/c mice 16 +/- 3 pM, and of C57BL/6 mice 14 +/- 3 pM. These physiological concentrations of alpha-MSH inhibited the production of IFN-gamma by antigen-stimulated lymph node cells. In contrast to the low molecular weight fraction, alpha-MSH did not inhibit proliferation. There was a 26% recovery of IFN-gamma production when alpha-MSH was absorbed from the low molecular weight fraction. The results demonstrate neuropeptides to be constitutive components of normal aqueous humor and that factors with the capability of differential regulation of effector T-cell activity may be present within the immunosuppressive ocular microenvironment.
Animals↗
Lipoproteins and lipids in cow and human aqueous humor.
The aqueous humor of the cow and human was examined for the presence of lipids and lipoproteins. Whole aqueous humor collected from cow eyes within 30 min after slaughter contained about 1 micrograms/ml of cholesterol and phospholipid. Upon fractionation of bovine aqueous into various density ranges following sequential ultracentrifugations , about 99% of the total cholesterol was recovered at a density of greater than 1.063. Apolipoprotein A-I, the major apolipoprotein of high-density lipoprotein (HDL), was the major protein seen upon electrophoresis of the 1.063-1.21 fraction. Particles of about 80 A mean diameter were observed by electron microscopy in the 1.063-1.21 fraction. Using rocket immunoelectrophoresis, a concentration of about 2 micrograms/ml of apolipoprotein A-I was measured in cow aqueous humor and slightly less in aqueous humor from the adult human collected post-mortem (1-36 h). In conclusion, aqueous humor of cow and man appears to contain about 4 micrograms/ml of HDL and it is likely the sole lipoprotein in this fluid. The potential importance of this lipoprotein in supplying lipids to the lens is discussed.
Animals↗
Lens epithelial cells in postoperative aqueous humor.
The aqueous humor during or after cataract surgery often contains red blood cells (RBCs) from blood; inflammatory cells from white blood cells (WBCs); fibrin, pigment cells, and fibroblasts from either the iris or the ciliary body; lens epithelial cells (LECs); and corneal endothelial cells. Since LECs may be related to postoperative complications, including a fibrin reaction and a secondary cataract, confirmation of their presence postoperatively not only in the capsular bag, but also in the aqueous humor, is necessary for identifying these complications. Using aqueous humor obtained from pig eyes, I attempted to identify LECs immunohistochemically in the aqueous humor, following phacoemulsification (PEA) and aspiration of the cortex, and found the presence of cells that react to keratin antibody, the marker for epithelial cells. Although these cells could be lens, conjunctival, or corneal epithelial cells, they were found following PEA and aspiration of the cortex, and therefore are believed to be LECs.
Animals↗
Antibody to Toxocara canis in the aqueous humor.
The aqueous humor and serum samples of patients with presumed ocular toxocariasis were examined by an enzyme-linked immunosorbent assay (ELISA) for antibody to the embryonated egg antigen. Using a single dilution (1:8), higher amounts of antibody have been found in the aqueous humor than in the serum samples. Antibody was not found in the serum or aqueous humor of patients with retinoblastoma, Coats' disease, uveal malignant melanoma, or central retinal artery obstruction. While two patients with presumed ocular toxocariasis had normal serum levels of antibody, the aqueous humor ELISA titers were greatly elevated, supporting the clinical diagnosis and suggesting localized antibody production.
Adult↗
Investigation of the pathogenesis of glaucoma capsulare with special discussion of alpha 1 Lp and Cp in aqueous humor.
The aqueous humor proteins of exfoliation syndrome were studied qualitatively by crossed immunoelectrophoresis and compared with normal controls. Two kinds of macromolecules (alpha 1-lipoprotein and ceruloplasmin) were detected more frequently in exfoliation syndrome than in the normal controls. Alpha 1 Lp was detected in eight of ten patients with exfoliation syndrome, but in none of the eight controls. Cp was detected in seven of ten patients with exfoliation syndrome, but in only one of the eight controls. The presence of these macromolecules in the anterior chamber suggests high permeability of vessels in the exfoliation syndrome. This interpretation is also supported by the fact that neovascularization is sometimes present in the iris of the exfoliation syndrome. In the aqueous humor from a patient with diabetic retinopathy, ten kinds of aqueous humor proteins were identified.
Adult↗
Quantitative study of characteristic aqueous humor transferrin, serum transferrin and desialized serum transferrin in aqueous humor.
Total transferrin (Tf) concentration and relative percentages of its subfractions, ie, characteristic aqueous humor Tf (Tfah), serum Tf (Tfs) and desialized serum Tf (Tau), in the aqueous humor of 30 patients were determined. According to the total Tf concentration, these patients were divided into the group with intact or mildly damaged blood aqueous barrier (BAB), consisting of cataract, glaucoma and central retinal artery occlusion patients, and the severely damaged BAB group, consisting of uveitis patients. In the intact or mildly damaged group, Tfah, Tfs and Tau revealed constant ratios of 60%, 26% and 14%; while in the severely damaged group, a relatively high concentration of Tfs was observed. There is only Tfs in the serum, therefore, theoretically, damage of the BAB should lead to an immediate increase of the relative concentration of Tfs in the aqueous humor. Because it did not occur until the BAB had been severely damaged, the possibility of an intraocular interchange of the 3 Tf subfractions is suggested.
Adolescent↗