Corneal Endothelial Permeability Following Storage in Moist Chamber and Mk Medium

Farkas

et al. 1983

Self Cite

Radial keratotomy was performed on Owl Monkey corneas using 8 incisions with sparing of a 3.5mm central pupillary area. Cornea endothelial membrane permeabilities were determined at 2 days, and 4 weeks, following the procedure using simultaneous flux determinations of 3H-labeled inulin and 14C-labelled dextran. Inulin permeability was increased 27% two days following the procedure, and had returned to levels comparable to the unoperated eye 4 weeks following the procedure. Dextran permeability was unaltered at both 2 days, and 4 weeks, following the procedure. This study has shown that radial keratotomy causes a transient reduction in endothelial barrier function with the production of physiologically significant 'holes' in the membrane in the immediate post-operative period. The relationship of this physiological alteration to ultimate endothelial cell function is, at the present time, unknown.

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Radial Keratotomy and Corneal Permeability in Owl Monkey

Farkas

et al. 1983

Self Cite

“…Corneas stored in this intermediate term preservative appear better able to maintain some of their physiologic characteristics than corneas stored as the whole eye in a moist chamber (Hull et al 1976;1979a,b, 1983a. The original MK medium utilized a bicarbonate buffer system which over time was found to lack stability resulting in fluctuations of solution p H .…”

mentioning

confidence: 99%

Effect of Hepes Buffer on Corneal Storage in Mk Medium

Thomas

1984

Self Cite

Rabbit corneas were stored for 7 days in either MK medium containing gentamicin or modified MK medium containing HEPES buffer, gentamicin and phenol red. Corneas stored for 7 days in modified MK medium were thicker than corneas stored in MK medium. Corneal endothelial permeability to inulin and dextran was similar following 7 days of storage in either solution. Transmission electron microscopy of corneal endothelial cells stored in either solution showed intact cell membranes and organelles. In vitro perfusion of rabbit corneas in the specular microscope with Krebs Ringer bicarbonate containing HEPES buffer swelled at 17 +/- 1 micron/h, whereas those perfused with Krebs Ringer bicarbonate alone swelled at 7 +/- micron/h. Perfusion with Krebs Ringer bicarbonate containing phenol red did not result in an increased corneal swelling rate. The work indicates that HEPES buffer has an adverse effect on corneal endothelial pumping function, and this results in corneal swelling during storage as well as during perfusion in the specular microscope. The adverse effect appears to be, at least in part, transient: however, the ultimate, long term effect of HEPES buffer on corneas stored prior to penetrating keratoplasty is not known and deserves continued investigation.

“…Previous clinical and experimental work has confirmed the efficacy of MK Medium (McCarey Kaufman medium: tissue culture medium 199 and 5% dextran) for the purpose of storing corneas prior to clinical usage for penetrating keratoplasty (McCarey et al 1974;Bigar et al 1975;Stark et al 1975;Waltman et al 1979;Hull et al 1967aHull et al , 1979. Most corneal surgeons have not utilized tissue stored in MK medium for periods longer than 72-96 h following death of the patient and placement of the corneal tissue in MK medium.…”

mentioning

confidence: 99%

Rabbit corneal endothelial physiologic and morphologic characteristics following storage in MK medium and K‐Sol

Frey

1986

Self Cite

Rabbit corneas were stored for 3, 7, 10 or 14 days in MK medium or K-Sol. Corneas were thinner immediately following removal from K-Sol than following removal from MK medium at all time periods studied. Following 3 days of storage, corneas stored in both solutions showed similar temperature reversal characteristics. Corneas stored for 7 and 10 days in MK medium also temperature reversed, whereas those stored in K-Sol did not. Corneas stored for 14 days in both solutions swelled following mounting in the specular microscope. Endothelial cell morphology was similar following storage in MK medium and K-Sol at all time periods studied. It is postulated that a persistant osmotic gradient is present across the endothelium following storage in K-Sol. This osmotic gradient occurs because of retention of chondroitin sulphate in the corneal stroma thereby preventing early temperature reversal.