Biomedical subjects

F Y Chiou

Publications and source records attributed to F Y Chiou.

6 recordsLinked to original sources

PubMed1993

Fish scale-induced dermatitis.

BACKGROUND: Fish scales loosened during the process of cleaning that come in contact with human skin will adhere and "grow," creating a raised skin lesion if not washed off immediately. OBJECTIVE: The purpose of this study was to examine the process of fish scale-induced dermatitis. METHODS: Fish scales from the blue gill (Lepomis machrochirus) were placed on the intact skin of denuded Swiss Webster mice that had no prior sensitization. RESULTS: The scales physically adhered and formed a raised fold of skin within minutes after placement. Lesions were submitted for pathologic evaluation on days 2 and 7. A subacute irritant dermatitis was observed that evolved into a chronic dermatitis with hyperkeratosis. Inverted fish scales (the anatomically reversed surface) and fish epidermis did not produce such lesions on the mice. CONCLUSION: Fish scales are able to induce an irritant dermatitis. They most likely do so through initial adhesion via mucopolysaccharide secretions.

Adhesiveness↗

PubMed1989

Effects of dopamine antagonists injected through vortex veins on intraocular pressure.

In order to avoid the factors of the corneal barrier and tearing washout on absorption of eye drops, dopamine and antagonists were injected into rabbit eyeballs through vortex veins. Many dopamine antagonists, such as haloperidol, moperone, metoclopramide, trifluperidol, lenperone, and fluoropipamide, lowered the intraocular pressure (IOP), whereas a few of them, such as chlofluperol and trifluoperazine, raised the IOP. Furthermore, it was found that dopamine agonists also could either increase or decrease the IOP. The ocular hypertensive effect of dopamine was blocked by haloperidol as expected. However, when the hypotension-inducing dopamine agonist, bromocriptine, and antagonist, haloperidol, were combined, the IOP remained unchanged. It was concluded that dopamine agonists and antagonists act at different sites and changes in IOP resulted from a combined summary of these complex effects. As a result, dopamine agonists and antagonists, while they may both lower the IOP when given alone, can antagonize each other through different sites and produce no net change in IOP.

Animals↗

PubMed1989

Microvascular access to the uveal tract in the rabbit eye for ocular pharmacologic studies.

Drug delivery to the eyes is quite inefficient regardless if the drugs are administered topically or intravenously. It is known that less than 1% of topically instilled drug can be absorbed into the eyes while even less of intravenously injected drugs reach the eyes. A research model has been developed in this study which allows delivery of drugs effectively to uveal and anterior structures of the eye. This experimental model allows drugs to be delivered to the eye via cannulation of and retrograde flow through the valveless vortex veins. In addition, the superficial branch of the vortex vein (draining the ciliary body and iris) or the deep branch (draining the choroid plexus of the retina) can be selectively cannulated to suit the researcher's needs. Finally, this procedure minimizes systemic drug actions which otherwise would complicate interpretation of experimental results. This model can be used for in vivo laboratory studies on (a) metabolic and physiological processes of the uveal tract in the eye, and (b) drug delivery to selective tissues of the uveal tract in the eye. Dose-response relationships of pilocarpine and timolol to lower intraocular pressure were demonstrated with this model.

Animals↗

PubMed1988

Effects of epinephrine on retinal and choroidal blood flow through different routes of drug administration.

Epinephrine (1, 3 and 10 micrograms/kg) was found to increase retinal and choroidal blood flow (22, 49 and 67%) when it was administered intravenously. The increase in retinal and choroidal blood flow coincided well with the increase in systemic blood pressure (44, 65 and 96%, respectively). When epinephrine (2%) was instilled to the eyes topically the retinal and choroidal blood flow decreased (15%) while systemic blood pressure remained unchanged. It is suggested that the decrease in retinal and choroidal blood flow by topical epinephrine could be the cause of epinephrine maculopathy reported previously. L-Timolol (0.25%, topically) did not affect retinal and choroidal blood flow significantly.

Administration, Topical↗

PubMed1985

Effects of prostaglandins on intraocular pressure recovery rate in rabbits.

The actions of a number of prostaglandins (PGs) were studied in unanesthetized rabbits using an intraocular pressure (IOP) recovery-rate method. In topical doses of 0.1 to 10 micrograms, these compounds accelerated the rate at which IOP returned to control levels after an infusion of hypertonic saline. In general, PGE1 appeared more potent than the other PGs at these doses. Arachidonic acid also increased the IOP recovery rate. The effect of arachidonic acid was completely blocked by the cyclooxygenase inhibitor indomethacin. Recovery rate responses to arachidonic acid were increased further after pretreatment with the lipoxygenase inhibitor phenidone. When administered alone, phenidone itself accelerated IOP recovery; this action was also blocked by indomethacin. The IOP recovery rate method appears to be a useful tool for studying ocular effects of PGs and other products or inhibitors of arachidonic acid metabolism.

Animals↗

PubMed1983

Dopaminergic involvement in intraocular pressure in the rabbit eye.

The involvement of dopamine in maintaining intraocular pressure (IOP) was investigated with the rabbit IOP recovery model after intravenous infusion of hypertonic saline. Dopamine facilitated the IOP recovery while reserpine did the opposite. When dopamine was administered after reserpinization, the IOP recovery was facilitated again. These results indicate that dopamine is involved in the maintenance of IOP because depletion of dopamine with reserpine resulted in an opposite effect produced by dopamine whereas administration of dopamine in reserpinized animals induced dopaminergic responses. Timolol produced similar effects as reserpine, which supports the idea that timolol reduces aqueous humor formation through elimination of dopaminergic function and reduction of blood flow in the ciliary body.

Animals↗