Biomedical subjects

N Z Gharagozloo

Publications and source records attributed to N Z Gharagozloo.

6 recordsLinked to original sources

PubMed1992

Aqueous dynamics in exfoliation syndrome.

Eighteen untreated patients with unilateral exfoliation syndrome without glaucoma were studied with regard to differences in aqueous dynamics between the affected and unaffected fellow eyes. Additionally, both eyes of the patients with exfoliation were compared to the eyes of 18 age-matched and gender-matched control subjects. Intraocular pressure was significantly higher (13.9 +/- 3.0 mm Hg [mean +/- standard deviation]) in the affected compared with the unaffected eyes (12.2 +/- 2.5 mm Hg), but no difference in aqueous humor flow was detected when eyes in the three groups were compared (affected eyes, 2.40 +/- 0.60 microliter/min; unaffected eyes, 2.40 +/- 0.65 microliter/min; control eyes, 2.61 +/- 0.60 microliter/min). Anterior chamber volumes were significantly smaller in affected (122 +/- 37 microliters) and unaffected eyes (121 +/- 37 microliters) of the patients with exfoliation compared with the eyes of the control subjects (145 +/- 30 microliters). Apparent resistance was higher in the eyes with exfoliation (6.5 +/- 1.9 min mm Hg/microliters) compared with both unaffected (5.4 +/- 1.2 min mm Hg/microliters) and control groups (5.2 +/- 1.8 min mm Hg/microliters), although these differences were not statistically significant.

Aged↗

PubMed1991

Effect of apraclonidine in long-term timolol users.

A double-blind, randomized study was undertaken to determine if the alpha-agonist apraclonidine has an additive effect in eyes treated with long-term timolol. Seventeen patients (15 with primary open-angle glaucoma, 1 with pigmentary glaucoma, and 1 glaucoma suspect) on long-term timolol treatment in both eyes received a single dose of apraclonidine in one eye and a placebo in the other. Aqueous flow and intraocular pressure were compared in the treated and untreated eyes. There was no statistically significant difference in pretreatment aqueous flow between the two eyes. When flow in the apraclonidine-treated eyes (1.39 +/- 0.41 microliter/min, mean +/- standard deviation) was compared with that of the untreated eyes (1.66 +/- 0.38 microliter/min), a statistically significant difference was found (P less than 0.01). Apraclonidine reduced intraocular pressure by 1.3 mmHg (P = 0.05). The implications of these findings on the understanding of the mechanism of action of adrenergic drugs in the human eye is discussed.

Adrenergic alpha-Agonists↗

PubMed1991

The correlation between serum progesterone and aqueous dynamics during the menstrual cycle.

Exogenously-administered progesterone has been shown to lower intraocular pressure. However, attempts to correlate endogenous progesterone levels and aqueous dynamics have produced inconsistent results. In this study, 20 healthy, non-pregnant women were followed over a 28-day menstrual cycle. Serum progesterone level, intraocular pressure, and aqueous flow rate were measured weekly. We were unable to demonstrate any correlation between progesterone levels and either aqueous flow or intraocular pressure.

Adult↗

PubMed1988

Thymoxamine reverses phenylephrine-induced mydriasis.

We performed a randomized double-masked evaluation of the alpha-adrenergic blocking agent thymoxamine (0.1%) as compared to placebo for the reversal of phenylephrine-induced mydriasis. Topically applied thymoxamine reversed the mydriasis from a single drop of 2.5% phenylephrine in 36 of 40 eyes (90%) within one hour. The mydriasis was completely reversed in 25 of 40 eyes (63%). Eyes with blue irides responded more quickly and more completely than did those with brown irides. The 40 contralateral eyes, which had also been dilated with phenylephrine, remained dilated or dilated further after receiving a placebo eyedrop. Twenty subjects (50%) reported mild transient ocular irritation upon instillation of thymoxamine. Thymoxamine was useful in individuals with narrow anterior chamber angles who were at risk of acute closed-angle glaucoma following dilation with an adrenergic agent.

Adult↗

PubMed1988

Terbutaline stimulates aqueous humor flow in humans during sleep.

A randomized, double-masked study of the effect of terbutaline sulfate, a selective beta 2-agonist, on the rate of aqueous humor formation was performed in awake and sleeping normal human subjects. The rate of aqueous formation was measured by fluorophotometry. Both the drug- and placebo-treated eyes showed a statistically significant nocturnal reduction of the flow rate (36% suppression in the terbutaline-treated eyes and 43% suppression in the placebo-treated eyes). Terbutaline had no effect on daytime aqueous flow rates, but stimulated flow by 15% during sleep. The drug had no significant effect on intraocular pressure. This study confirms past observations that beta-agonists exert their maximal effects during sleep, when endogenous adrenergic stimulation is at a minimum.

Adult↗

PubMed1988

Aqueous flow is reduced by the alpha-adrenergic agonist, apraclonidine hydrochloride (ALO 2145).

Apraclonidine hydrochloride (ALO 2145), a clonidine derivative that does not cross the blood-brain barrier, was applied topically to one eye of each of 20 normal human subjects. The rate of aqueous humor flow and the permeability of the blood-aqueous barrier were measured by fluorophotometry. Four hours after administration, the flow rate in the apraclonidine-treated eyes was 35% lower than that measured in the control eyes. Three hours after instillation, the intraocular pressure (IOP) was 34% lower in the apraclonidine-treated eyes when compared with control eyes. Both these differences were statistically significant. The drug had little, if any, effect on blood-aqueous permeability.

Administration, Topical↗