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At least 1,063 records · Page 59Linked to original sources
PubMed1975

[Aqueous humor pH in experimental lye burns and influence of different treatment measures (author's transl)].

300 rabbit corneas were burned for 1 minute by applying a filter paper of 10 mm diameter soaked in different concentrations of NaOH. The aqueous humor pH was then measured at certain time intervals and after different treatment methods until the physiologic pH of 7.6 was reached. The results were statistically analysed. Group 1, 2 and 3 were burned in 1n NaOH, 3n NaOH, and 6n NaOH respectively without any treatment. In these groups a "therapeutic" pH-level of 8.5 was measured on an average 0.5, 2.5 and 5 hours after the burn (Table 1 and Fig. 2). Group 4 and 5 again were burned with 6n NaOH. In group 4 the burn was followed by constant irrigation with physiologic saline solution by means of the Morgan Therapeutic Lens (Fig. 1a and b). With this regimen a pH of 8.5 was reached after 2.5 hours (Table 1 and Fig. 3). In group 5 the physiologic saline solutions was replaced by a buffer solution (Isogutt) and a pH of 8.5 was measured after only one hour (Table 1 and Fig. 3). Based upon these results it is felt that severe lye burns should be treated by constant irrigation with a buffer solution for several hours. A treatment that can easily be performed by use of the Morgan Therapeutic Lens.

Animals↗
PubMed1977

[Tonographic and tonometric aqueous humor outflow tests after trabeculotomy (author's transl)].

In 10 eyes which trabeculotomy was performed because of primary open angle glaucoma preoperatively, 1 to 3 months and 12 months postoperatively the diurnal curves and tonographic results were compared. The i.o. pressure was reduced in all eyes. The ocular rigidity was decreased from 0.0206 +/- 0.0019 (s.d.) preoperatively to 0.0164 +/- 0.0015 after 1 to 3 months and to 0.0168 +/- 0.0017 after 12 months. Regarding the individual change of ocular rigidity, the outflow facility was improved on an average of from 0.13 +/- 0.02 preoperatively to 0.37 +/- 0.10 or 0.20 +/- 0.03 units postoperatively. This means a reduction of the resistance to aqueous outflow from 10.62 +/- 1.89 to 3.88 +/- 0.57 or 5.77 +/- 0.77 units. The differences are statistically significant. If the changings of ocular rigidity are not regarded there is no significant improvement of the conditions of aqueous humor outflow.

Aged↗
PubMed1999

[Role of lactate dehydrogenase (LDH) level in the aqueous humor in the diagnosis of retinoblastoma (RB)].

In spite of the progress of the imagery in ophthalmology, the retinoblastoma remains in some particular cases, difficult to make. Moreover, the therapy sanction is often heavy. The lactate dehydrogenase (LDH) dosage in aqueous humor is an invasive technique conceivable when there are diagnosis problems particularly in retino-blastoma of old children and in affections simulating retino-blastoma. The purpose of this work is to lay out three observations where the LDH dosage enabled to keep the retinoblastoma diagnosis in one 8-year old child and eliminate it in two children having pseudoglioma with spontaneous evolution allowing to confirm the non-tumoral nature of the affection. Thus, the technique of LDH dosage has been reliable for the 3 cases which we have introduced. The authors compare the reliability of the different cytochemical techniques during the retinoblastoma diagnosis.

Aqueous Humor↗
PubMed1983

Effects of contact lens wear on mitosis of corneal epithelium and lactate content in aqueous humor of rabbit.

Various types of contact lenses, i.e., poly-methyl-methacrylate hard lenses, poly-2-hydroxyethyl-methacrylate soft lenses and two kinds of gas-permeable hard lenses with different permeabilities to oxygen, were placed on one eye of the albino rabbit for varying lengths of time. Using the fellow eye as the control, studies were carried out of the effects of the lens wear on the mitosis in the corneal epithelium and the lactate concentration in the aqueous humor. The contact lens wear suppressed the mitosis and increased the concentration of aqueous lactate, the degree of changes being greater as the permeability of the lens to oxygen decreased and the period of wear became longer.

Animals↗
PubMed1988

[Assessment of aqueous humor dynamics with Ulrich oculopressure tonometry].

Oculopression tonometry according to Ulrich can be used for the judgement of the facility of outflow like the tonography according to Grant. As shown by us for the first time, oculopression tonometry can also serve to evaluate aqueous humor formation. The results of a planned prospective study in 30 glaucoma patients and in 30 healthy volunteers are shown. It can be concluded that the recovery time of the intraocular pressure seems to be a better criterion for the diagnosis of glaucoma than the intraocular pressure measured immediately after the artificial pressure enhancement.

Aqueous Humor↗
PubMed1982

Cefoperazone concentrations in human aqueous humor after intravenous administration.

Twenty-four patients about to undergo elective cataract surgery received either a 2-g (ten patients) or a 4-g (14 patients) intravenous infusion of cefoperazone one to six hours before surgery. The 4-g dose produced a mean peak aqueous humor concentration of 2.93 micrograms/ml at one hour; the mean concentration remained higher than 2 micrograms/ml for at least four hours. These levels, however, were never more than 90% of the minimum inhibitory concentration of cefoperazone for common bacterial ocular pathogens.

Aqueous Humor↗
PubMed1992

Aqueous humor polyamines and alkaline phosphatase activity in endotoxin-induced uveitis: correlations to diverse leukocyte subsets.

The polyamines putrescine, spermidine and spermine have been proposed to be a part of the acute phase inflammatory response. They have been shown to be useful markers for cellular kinetics and change with various pathological conditions. The hypothesis that aqueous humor polyamines could be used to follow the time course of an endotoxin-induced inflammation in the eye was investigated. Additional parameters studied were the amount of aqueous leukocytes, alkaline phosphatase activity, distribution of leukocyte subsets and breakdown of the blood-aqueous barrier. Aqueous leukocytes, protein, alkaline phosphatase activity, putrescine and acetylated spermidine increased significantly as a response to inflammation during the first days after uveitis induction. Spermidine decreased 24 h after injection and seemed to rise thereafter. The different polyamines, except spermidine, correlated to the diverse infiltrating leukocyte subsets. These observations indicate that aqueous polyamines may be applied as valid markers for inflammation in the eye.

Alkaline Phosphatase↗
PubMed1976

Aqueous humor dynamics in glaucomato-cyclitic crisis.

The transfer coefficients of fluorescein in the anterior chamber by flow, kfa, and by diffusion, kdpa, can be calculated for an individual human eye, through an analysis of fluorescein concentrations in the anterior chamber, pupillary aqueous, and serum ultrafiltrates following intravenous injection. Using this technique, aqueous humor dynamics was studied in eight patients with glaucomato-cyclitic crisis. In seven patients, the coefficients determined during the attacks averaged 1.23 +/- 0.08 (S.E.M.) X 10(-2) min.-1 for kfa and 3.51 +/- 0.81 X 10(-3) min.-1 for kdpa in the involved eye, and 0.91 +/- 0.12 X 10(-2) min.-1 for kfa and 1.36 +/- 0.39 X 10(-3) min.-1 for kdpa in the fellow eye. The differences in the coefficients between the two eyes were statistically significant (P less than 0.05). In six patients, the coefficients were measured during the remission, giving average values of 0.81 +/- 0.08 X 10(-2) min.-1 for kfa and 1.36 +/- 0.16 X 10(-3) min.-1 for kdpa in the involved eye, and 0.78 +/- 0.07 X 10(-2) min.-1 for kfa and 1.20 +/- 0.10 X 10(-3) min.-1 for kdpa in the fellow eye. The differences in the coeficients between the two eyes were not significant. In five patients, the determinations were repeated during the attack and remission, and the differences in the coefficients between both phases were statistically significant (P less than 0.05) in the involved eye.

Adult↗
PubMed1988

6-amino-2-benzothiazole-sulfonamide. The effect of a topical carbonic anhydrase inhibitor on aqueous humor formation in the normal human eye.

The carbonic anhydrase inhibitor, 6-amino-2-benzothiazolesulfonamide, formulated as a 3% suspension in a gel vehicle was instilled in one eye of 21 human subjects in a single dose study to determine its effect on aqueous dynamics. A small but statistically significant effect on aqueous humor flow was observed 2 to 7 hours after application. By 8 hours, the effect had disappeared, and intraocular pressure (IOP) measured 8 hours after application of a single dose was unchanged in these normal volunteers. The drug and its vehicle caused local side effects including irritation, hyperemia, and blurred vision. The authors wondered if multiple doses would produce a greater effect. Four subjects received up to four doses of the drug over 2 days and were restudied. Marked bulbar injection and follicular conjunctivitis, attributable to either the drug or the vehicle, developed in two of the subjects, both contact lens wearers. A milder form of bulbar injection and follicular conjunctivitis developed in a third subject, who received three doses of the drug and was not a contact lens wearer. These side effects precluded additional multiple-dose testing of this formulation of the drug, and no conclusions about the effect of the drug on aqueous flow can be drawn from this portion of the study.

Adult↗
PubMed2003

Effects of oral administration of methazolamide on intraocular pressure and aqueous humor flow rate in clinically normal dogs.

OBJECTIVE: To determine magnitude and duration of the effect of oral administration of methazolamide at 2 dosages on intraocular pressure (IOP) in dogs in single-dose and multiple-dose trials and to determine aqueous humor flow rate (AHFR) by use of anterior segment fluorophotometry before and during treatment. ANIMALS: 25 healthy adult Beagles. PROCEDURE: Baseline IOPs and AHFRs were determined on days 0 and 1, respectively. On day 2, the single-dose trial was initiated with oral administration of 25 or 50 mg of methazolamide at 7 AM to 2 groups of 10 dogs each. Five dogs served as controls. In the multiple-dose trial, the same dogs received 25 or 50 mg of methazolamide at 7 AM and at 3 and 11 PM on days 3 through 9. RESULTS: Intraocular pressures varied diurnally with highest IOPs in the morning. In the single-dose trial, IOP decreased significantly at 3 to 6 hours after treatment and then increased significantly at later time points, compared with baseline values. In the multiple-dose trial, dogs in both treatment groups had significantly lower IOPs during the treatment period at 10 AM and 1 PM but not at 6 and 9 PM, compared with baseline values. In both treatment groups morning IOPs had returned to baseline values by the first day after treatment. Evening IOPs were significantly increased by 2 to 3 days after treatment, compared with baseline values. The AHFRs in both treatment groups were significantly lower than pretreatment AHFRs. CONCLUSIONS AND CLINICAL RELEVANCE: Oral administration of methazolamide decreases IOPs and AHFRs in clinically normal dogs, with effectiveness diminishing in the evening.

Administration, Oral↗
PubMed1987

Aqueous humor dynamics in experimental iridocyclitis.

Ocular inflammation was induced by intravitreal bovine serum albumin (BSA) injection in one eye of each of six cynomolgus monkeys. The fellow eyes were injected with sterile saline alone. The intraocular pressure decreased by 12.2 +/- 1.3 mmHg (mean +/- SE) 2 days after BSA injection and 4.0 +/- 1.1 mmHg after saline injection. Aqueous flow and uveoscleral outflow were determined with fluorescein isothiocyanate (FITC) dextran 70. Aqueous flow in inflamed eyes averaged 0.32 +/- 0.04 ul/min, less than half the rate of control eyes (0.77 +/- 0.08 ul/min, P = 0.01). The facility of uveoscleral outflow in inflamed eyes was four times that of control eyes (0.2 +/- 0.03 vs 0.05 +/- 0.01 ul/min/mmHg, respectively, P = 0.009). Fluorescence microscopic examination revealed intense fluorescence of the edematous ciliary body muscle and of the suprachoroidal space extending to the posterior pole. These findings indicate that BSA-induced ocular inflammation causes a simultaneous reduction in aqueous humor flow and an increase in uveoscleral outflow, resulting in ocular hypotony.

Animals↗
PubMed1993

Effect of oxymetazoline on aqueous humor dynamics and ocular blood flow in monkeys and rabbits.

OBJECTIVE: To evaluate the ocular effects of oxymetazoline hydrochloride, an alpha 2 agonist, in cynomolgus monkeys and albino rabbits. METHODS: Intraocular pressure was measured before and for 6 hours after application to glaucomatous monkey eyes. Outflow facility and aqueous flow rates were measured in normal monkey eyes. Uveoscleral outflow was measured in rabbit eyes. Ocular peak pulse volume was determined with the ocular blood flow system in normal and glaucomatous monkey eyes. RESULTS: Single applications of ozymetazoline reduced (P < .001) intraocular pressure up to 6.0 +/- 1.0 mm Hg (mean +/- SEM). Enhancement of the ocular hypotensive effect was observed with 5-day twice-daily administration. Outflow facility was unaltered; aqueous flow rate was decreased (P < .001) by 39% in the treated eyes compared with baseline values; and uveoscleral outflow was increased (P < .005) by 56% in the treated eye. Peak pulse volume was unchanged. CONCLUSION: Oxymetazoline reduces intraocular pressure by decreasing aqueous humor flow rates and increasing uveoscleral outflow. Oxymetazoline may have clinical potential as an ocular hypotensive drug.

Animals↗
PubMed2006

Chloride secretion by porcine ciliary epithelium: New insight into species similarities and differences in aqueous humor formation.

PURPOSE: To investigate the electrophysiology and mechanisms of chloride (Cl-) transport across the ciliary body-epithelium (CBE) of the porcine eye. The pig is widely believed to be a good model for studying human physiology. Current results strengthen our understanding of the physiology of aqueous humor formation (AHF). METHODS: Freshly isolated porcine CBE were maintained in modified Ussing-Zerahn-type chambers. The effects of the bathing anion substitution (Cl- and HCO3-) and transport inhibitors including bumetanide, 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid disodium salt (DIDS), heptanol, and two chloride channel inhibitors, 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB), and niflumic acid, on the electrical properties and transepithelial Cl- transport were investigated. RESULTS: Viable porcine CBE preparations were maintained in vitro. A spontaneous transepithelial potential difference (PD) of approximately 1 mV was found across the CBE (aqueous side negative). The magnitudes of the PD and short-circuit current (I(sc)) were found to be dependent on both the bathing Cl- and HCO3- concentrations. In short-circuited conditions, a significant net Cl- transport (1.01 microEq x h(-1) x cm(-2); n = 109; P < 0.001) in the stromal-to-aqueous direction (J(net)Cl) was detected. The magnitude of the Cl- current carried by the J(net)Cl was approximately 2.2 times the measured I(sc), suggesting there was cation (e.g., Na+) transport along with Cl- and/or anion transport (e.g., HCO3-) in the opposite direction. Bilateral bumetanide (0.1 mM) reduced the J(net)Cl by approximately 56% while stromal DIDS (0.1 mM) produced no inhibition. Instead, aqueous DIDS (0.1 mM) triggered a sustained stimulation of both I(sc) and J(net)Cl. Even if bilateral DIDS was used at a higher concentration (1 mM), together with bilateral dimethylamiloride (DMA, 0.1 mM), no inhibition of the I(sc) was observed. Bilateral heptanol (3.5 mM) drastically reduced the I(sc) and J(net)Cl. NPPB (0.1 mM), a common chloride channel inhibitor, did not inhibit the J(net)Cl, whereas NFA (1.0 mM) virtually abolished it. CONCLUSIONS: In the porcine eye, active secretion of Cl- into aqueous was identified that may act as a driving force for AHF. The bumetanide-sensitive Na+/K+/2Cl- cotransporter (NKCC) clearly contributes to the Cl- uptake into the pigmented epithelium (PE), whereas the DIDS-sensitive Cl-/HCO3- anion exchanger (AE) may exert a minor role. The intercellular gap junctions couple the porcine ciliary bilayers and thus the transepithelial Cl- transport, as in other species. The Cl- channel/efflux pathway located in the nonpigmented epithelium (NPE) is niflumic acid-sensitive but NPPB-insensitive. We also hypothesize that the AE located on the NPE may regulate the activity of a putative Cl- channel on the basolateral membrane facing aqueous via modulation of the intracellular pH (pHi). This work reinforces the general consensus that active secretion of Cl- is the major driving force of AHF in mammalian eye and further substantiates the existence of species differences in the mechanism that accomplishes transepithelial Cl- transport.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1982

[Studies with azlocillin, mezlocillin, penicillin-g-potassium and sisomicin on tolerance in the cornea and the kinetics of inhibiting concentrations in the cornea and aqueous humor in rabbits].

We studied the effect of azlocillin, mezlocillin and sisomicin in concentrations of 1, 2.5 and 5% on the regeneration of stromal corneal wounds in rabbits following subconjunctival injections and treatment with eye drops. Concentrations of the antibiotics were also determined in corneal tissue and in aqueous humor and compared with that of penicillin G-potassium. Together with azlocillin, sisomicin proved to be the most effective and the safest. Mezlocillin only inhibited wound regeneration slightly and thus mezlocillin appears to be inferior to the other two antibiotics investigated in the local treatment of the eye.

Animals↗