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At least 37 records · Page 2Linked to original sources
PubMed1975

Ciliary ganglion stimulation. I. Effects on aqueous humor inflow and outflow.

Stimulation of the ciliary ganglion in an enucleated, arterially perfused cat eye preparation produced a sustained increase in aqueous humor formation and an increase in the rate of aqueous humor outflow. The increased aqueous humor formation induced by ciliary ganglion stimulation has been found to be pressure-dependent and therefore suggests that ultrafiltration may be the underlying mechanism of action. No change in capillary permeability of the ciliary body could be demonstrated.

Acetylcholine↗
PubMed1976

Lipid-laden aqueous humor associated with anterior uveitis and concurrent hyperlipemia in two dogs.

Two dogs with cloudy aqueous humor due to accumulation of lipid and lipoprotein had concurrent hyperlipemia and anterior uveitis. In 1 dog, serum and aqueous humor had similar lipoprotein electrophoretic patterns, and in the other dog, the patterns were different. The therapeutic approach included symptomatic treatment of the uveitis and reduction of dietary fat intake. Clearing of fat from aqueous humor followed control of the uveitis.

Animals↗
PubMed1975

[A contribution to the study of the correlation between the depth of the anterior chamber and the coefficient of aqueous humor outflow (author's transl)].

The depth of the anterior chamber was measured and the coefficient of the aqueous humor outflow was ascertained by means of tonography in 88 normal eyes. The mean value of the depth of the anterior chamber established was 2095+/-0.42 and the median value of the outflow coefficient of the aqueous humor was found to be 0.27+/-0.07. Both values showed a regular distribution. A statistically significant correlation was established between the two values. Expressed through a correlation coefficient this would mean in practice that the coefficient of aqueous humor outflow is affected up to 10 percent by the value of the depth of the anterior chamber.

Adolescent↗
PubMed1975

Chloramphenicol in aqueous humor after topical application.

Chloramphenicol 0.5% ophthalmic solution was applied topically to patients at various times before cataract surgery. The aqueous humor was obtained at the time of surgery and analyzed for chloramphenicol content by thin-layer chromatography. Aqueous humor chloramphenicol levels ranged from 3.5mn-g/ml to 6.7mn-g/ml at the initial sampling period one to two hours following topical administration. Chloramphenicol was measurable in samples for up to five hours following administration. The compound measured in the aqueous humor samples was chemically identified as intact chloramphenicol, and no metabolites of chloramphenicol were shown.

Aged↗
PubMed1975

Electrolyte and acid-base status of aqueous humor in perinatal and adult goats.

These experiments were undertaken to determine electrolyte concentration and acid-base status of aqueous humor and arterial plasma H2O in perinatal and adult goats. The distribution of potassium, sodium, chloride, magnesium, and calcium between aqueous humor and plasma H2O in fetal, neonatal, and adult goats changed independently with age and could not be explained by passive Gibbs-Donnan equilibria. Anterior chamber aqueous humor has a reduced pH, PO2, HCO3-, and an elevated PCO2 compared to arterial blood in the neonate and adult.

Acid-Base Equilibrium↗
PubMedDate not supplied

Pediatric dosing considerations in ophthalmology--dosage adjustments based on aqueous humor volume ratio.

By simplifying a pharmacokinetic treatment, an equation can be derived which predicts that equal areas under aqueous humor concentration-time profiles can be obtained by administering a dose to infants which is some fraction of the normal adult dose. This fraction is obtained by dividing the aqueous humor volume of the child by that of the adult. This theory has been tested using rabbits as an experimental model. Using literature values for aqueous humor volumes, it was possible to calculate what fraction of a dose of pilocarpine administered to 20-day-old rabbits would result in the same ocular concentrations of drug as in 60-day-old rabbits. When the experiment was performed, agreement between predicted and experimental values was excellent. Although admittedly an oversimplified treatment, these results are the first step in a comprehensive pharmacokinetic model which should result in a more rational approach to ophthalmic drug delivery in infants and children.

Animals↗
PubMed1978

The penetration of antistaphylococcal antibiotics into the aqueous humor of rabbits.

A multiple dose schedule of antibiotic administration parallels the clinical therapeutic situation. However, most reported studies on the aqueous humor concentration of antibiotics have been carried out following single doses of drug. We administered 2 penicillinase-resistant penicillins, 2 cephalosporins, and gentamicin to rabbits over a 24 hour period. Samples of serum and aqueous humor were obtained after the first and after the fifth dose of antibiotic. Of the agents studied, only methicillin in multiple doses gave therapeutic concentrations in the aqueous humor of normal rabbits. It is proposed that any future studies of intraocular penetration of antimicrobials be designed to include single and multiple doses in normal and infected eyes.

Animals↗
PubMed1979

Experimental ciliochoroidal detachment. Effect on intraocular pressure and aqueous humor flow.

Ciliochoroidal detachments were produced in rhesus monkeys by injecting glutathione bicarbonate Ringer's solution, autologous serum, or silicone oil into the anterior suprachoroidal space. Silicone oil detachments, like sham operations, caused a transient 2 mm Hg reduction in intraocular pressure. Detachments with glutathione bicarbonate Ringer's solution or serum caused a 6 mm Hg reduction in intraocular pressure, which normalized in three weeks. Aqueous humor flow in serum-detached eyes was normal, indicating that the hypotonia does not result from reduced aqueous humor formation. Blood was present in Schlemm's canal in most eyes with hypotonia, which suggests that hypotonia is not the result of enhanced conventional aqueous humor outflow. Therefore, it is postulated that hypotonia might result from enhanced aqueous humor outflow from the anterior chamber into the suprachoroidal space and out of the eye through the emissarial channels of the sclera (uveoscleral outflow).

Animals↗
PubMed1977

Lactate dehydrogenase levels and isoenzyme patterns in the serum and aqueous humor of adult cataract patients.

Serum and aqueous humor lactate dehydrogenase (LDH) levels were assayed in 46 patients with senile cataracts at the time of cataract extraction. The mean aqueous level was 37 IU/liter and the mean serum level 152 IU/liter. In each case, the serum LDH level was higher than the corresponding aqueous LDH. The LDH isoenzyme levels were also determined; LDH 4 and LDH 5 were elevated in cataract aqueous samples, while the serum isoenzymes were normal. The LDH studies of normal and diseased globes must be rigorously standardized to avoid artificially high or low levels.

Adult↗
PubMed1979

[The determination of IgE in human aqueous humor in a case of intraocular parasitosis (ophthalmomviasis interna) (author's transl)].

A case of intraocular myasis is here reported, as well as the difficulties of diagnosis--mostly too late--of this disease, which is rare in Europe and the northern hemisphere and which leads, almost invariably, to functional or even anatomical loss of the eye.--The determination of IgE in human aqueous humor (ah) and corresponding serum (s) by means of the ultrasensitive and quite simple PRIST method could represent a possibility of timely diagnosis, and this theoretically too in the case of other, much more frequent oculoparasitosis cases.--A retrospective study of the preoperative aqueous humor of the ophthalmomyiasis case presented here revealed an IgE concentration of 113 U/ml in the aqueous humor, with only 3 U/ml (1 U congruent to 2 ng) in the corresponding serum. A simple serum-IgES-determination would not have permitted the diagnosis--at least not in the case examined--just as little as numeration of eosinophilic granulocytes in blood and/or aqueous humor.

Aqueous Humor↗
PubMed1975

Prostaglandin-like activity in the aqueous humor following alkali burns.

Following application of 20 mul of 2 N sodium hydroxide to the rabbit cornea, the prostaglandin-like activity in the aqueous humor increased from undetectable levels to around 30 ng, per milliliter, a level which was sustained for up to 24 hours. This increase correlated with the previously reported sustained elevation of intraocular pressure following a 20 mul alkali burn. Pretreatment with aspirin or indomethacin virtually abolished the increase in intraocular pressure and elevation of prostaglandin-like activity in the aqueous humor following a 20 mul burn. Marked ocular hypotension following 50 mul and 100 mul sodium hydroxide burns correlated with very low prostaglandin-like activity in the aqueous humor. The low prostaglandin-like activity probably resulted from alkaline hydrolysis of aqueous prostaglandins and massive cellular death in iris and ciliary body tissues.

Alkalies↗
PubMed1979

Fluorescein angiography and changes in aqueous humor protein after argon laser photomydriasis in rabbits.

In brown-eyed and blue-eyed rabbits, irises treated with argon laser photomydriasis (ALP) were studied by using fluorescein angiography and by evaluating the aqueous humor protein concentration. The following results were obtained. Immediately after ALP, a breakdown of the blood-aqueous barrier is demonstrated by a marked influx of fluorescein into the ciliary processes and into the anterior and posterior chambers. The dye flow into the aqueous humor decreases to normal values within 3 days. There is no fluorescein leakage from laser impacts themselves. Peripupillary capillary loops are permanently occluded, but in a few cases, recanalization occurs. Neovascularization did not occur during 56 days of observation. ALP initially leads to a six- to eightfold increase in normal aqueous humor protein concentration, which decays to normal values within 3 days.

Animals↗
PubMed1978

Immunoglobulin E in human aqueous humor and corresponding serum. A physiopathological and clinical study.

The analysis of IgE in aqueous humor yielded an average concentration of 3.4 +/- 0.97 U/ml for 22 cataract patients and 5.5 +/- 3.42 U/ml for five uveitis patients. The IgE level in aqueous humor (IgEa.h.) of the cases examined is most probably, beside hematoocular diffusion of serum IgEs, the result of intra-ocular IgE production. In comparison with (mostly normal) IgEs levels, the IgEa.h. concentration appears relatively elevated, not only with uveitis patients, but also with cataract patients, above all when lenticular opacity is accompanied by other ophthalmic diseases (glaucoma, high myopia, diabetes). This "increase" of IgEa.h. concentration in very probably due to the radioimmunosorbent (RIST) technique employed, the most sensitive method available at the time of the present study. Thus, the calculated IgEa.h. value in the cataractous eyes should be regarded simply as approximate to the normal IgEa.h. concentration. These values are of clinical significance however, since a reference IgEa.h. mean-value is indispensable to the interpretation of pathologically high IgEa.h. levels and ethics do not permit of IgEa.h. determination in healthy eyes. The mean IgEa.h. levels of the delayed-type uveitis and cataract patients examined reveal no significant differences. IgEa.h. determination could make a contribution to the etiological clarification of, for example, immediate-type uveitis cases and intra-ocular parasitosis and serve as an appropriate model to study intra-ocular immunomechanisms.

Adult↗
PubMed1979

Sickled erythrocytes, hyphema, and secondary glaucoma: IV. The rate and percentage of sickling of erythrocytes in rabbit aqueous humor, in vitro and in vivo.

The number of erythrocytes adopting the sickled configuration in rabbit aqueous was determined with a masked counting technique in vitro and in vivo. The percentage of cells that became sickled in aqueous humor was greater than that observed in a control salt solution and in the donor blood itself. Aqueous humor, therefore, can be considered a particularly deleterious medium for erythrocytes having a propensity for sickling. Blood samples from six donors with systemically severe hemoglobinopathies (SC, Sthal, and SS) had relatively high levels of hemoglobin S and, in general, showed faster and more frequent sickling than did blood samples from donors with low levels of hemoglobin S (one SS patient, whose chronic blood transfusion regimen had replaced most of his hemoglobin S with normal hemoglobin, and two AS patients). Even erythrocytes from sickle cell trait cases, however, were capable of sickling when immersed in acqueous humor.

Anemia, Sickle Cell↗