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Biomedical subjects

G J Petursson

Publications and source records attributed to G J Petursson.

6 recordsLinked to original sources
PubMed1983

Topical timolol and epinephrine: biochemical actions and interactions in the rabbit eye in vivo.

The effects of topical 0.5% timolol maleate and 1% or 2% levo-epinephrine hydrochloride on aqueous humor cyclic-AMP and intraocular pressure were assessed in 97 normotensive New Zealand white rabbits in vivo. The study was conducted using three experimental protocols: (A) timolol and epinephrine individually, (B) timolol and epinephrine in coadministration, and (C) timolol and epinephrine in crossover, applied either in a single dose, twice a day for two days, and/or twice a day for six days. These studies demonstrated that timolol has complex biochemical actions, one of which is beta-adrenergic antagonism. By itself, timolol had no effect on cyclic-AMP levels. However, when used in both single-dose coadministration and in pretreatment in six-day crossover with epinephrine, it significantly diminished the cyclic-AMP elevation produced by a single dose of epinephrine. In the six-day crossover protocol, pretreatment with timolol also significantly reduced the ocular hypotensive effect of a single dose of epinephrine, thereby correlating biochemical cause with clinical effect. Yet, timolol alone had no ocular hypotensive effect. Therefore, timolol's biochemical actions in this animal model cannot explain its marked clinical efficacy in man, which appears to depend on more complex pharmacologic actions.

Administration, Topical↗
PubMed1979

Repair of an inadvertent buttonhole or leaking filtering bleb.

Buttonholing of conjunctival flaps at the time of filtering glaucoma surgery or a leak in the flap postoperatively can cause serious problems and may be most difficult to repair. A new delicate atraumatic needle has been used successfully in five cases to close conjunctiva to conjunctiva or conjunctiva to cornea defects.

Aged↗
PubMed1979

The use of liquid nitrogen cryospray for treatment of trichiasis.

Cryosurgical destruction of eyelashes has been successful using a double freez-thaw liquid nitrogen spray technique. While other cryogens are successful in treating trichiasis, they are contraindicated in the treatment of malignant eyelid lesions. If the clinician intends to treat both these entities, it would be simpler to use a liquid nitrogen unit; otherwise, two separate cryosurgical instruments would be required. The liquid nitrogen treatment requires two cycles of a rapid freeze to -15 degrees C coupled with a slow thaw and has given us a 90%+ success rate. Contraindications in treating trichiasis with cryotherapy include paralytic lids and heavily pigmented patients. In general, we do not treat trichiasis involving less than one-third of the lid, especially with young, healthy-appearing lid margins.

Cryosurgery↗
PubMed1979

Decreased libido--a side effect of carbonic anhydrase inhibitor.

Thirty-nine cases of decreased libido in glaucoma patients on carbonic anhydrase inhibitors are reported. This symptom completely reversed or markedly improved after discontinuation of the drug in all cases. Twelve of these patients restarted their carbonic anhydrase inhibitor medication which resulted in a recurrence of decreased libido symptoms. There were 3 cases of impotency which reversed after discontinuation of the drug. Most likely, these symptoms are a result of the malaise and depression occurring in some patients on carbonic anhydrase inhibitor therapy.

Adult↗