Biomedical subjects

L Cheeks

Publications and source records attributed to L Cheeks.

39 records · Page 3Linked to original sources

PubMed1986

The interrelationship between intraocular pressure and Honan Intraocular Pressure Reducer pressure.

The relationship between the pressure applied to the enucleated human eye using the Honan Intraocular Pressure Reducer (HIPR) and the peak intraocular pressure as a function of initial intraocular pressure has been examined. The peak intraocular pressure is linearly related to the applied HIPR pressure whether the latter is 30, 50, or 75 mm Hg. The slopes relating peak intraocular pressure to initial intraocular pressure at different HIPR settings are parallel. Use of the HIPR at settings greater than 30 mm Hg and an initial IOP of greater than 30 mm Hg could compromise ocular vascular perfusion.

Humans↗

PubMed1986

Distribution of a steroid antagonist in the eye following topical administration.

The distribution of a steroid antagonist, RU486, that is known to reduce rabbit intraocular pressure has been examined in the eye. On an equal tissue weight basis, the corneal epithelium is the site of maximal absorption followed by conjunctival tissues (bulbar and palpebral) and the rest of the cornea. Aqueous humor concentrations of drug vary between 5 X 10(-6) and 5 X 10(-8) at 1 and 24 hours, respectively: these concentrations have been shown by others to inhibit dexamethasone binding to rat thymocytes, and are sufficient to act as an antagonist at steroid receptors in the eye. Multiple drop administration for 10 days (3 drops per day) revealed no accumulation in the treated eye, but did show the presence of drug in the untreated contralateral eye that could explain the contralateral pharmacological effect seen on intraocular pressure after several days of treatment.

Administration, Topical↗

PubMed1986

Effect of ambient pH on corneal endothelial sodium fluxes.

Sodium fluxes across the isolated rabbit corneal endothelium were measured as a function of ambient pH and bicarbonate concentrations. At pH 7, the net sodium flux (J endo str net) was effectively obliterated at all bicarbonate concentrations, relative to controls at pH 7.5. At pH 8, the net sodium flux was obliterated at 5 mM bicarbonate, was unchanged at 25 mM bicarbonate, and was enhanced at 40 mM bicarbonate, relative to controls at pH 7.5. The decrease in net sodium flux under these conditions relative to previously demonstrated maintenance of bicarbonate fluxes under almost identical conditions suggest that sodium and bicarbonate transverse the endothelium by different routes. In addition, changes in unidirectional fluxes, when ambient pH is decreased from 7.5 to 7, are not equal, illustrating that the fluxes probably occur via different pathways. A complex interrelationship exists between sodium, bicarbonate, and proton movement.

Animals↗