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Biomedical subjects

F M Polack

Publications and source records attributed to F M Polack.

103 records · Page 6Linked to original sources
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Contributions of electron microscopy to the study of corneal pathology.

Most of the electron microscopic studies of pathological corneas have been done only recently. Keratoplasty has been the most important source of specimens for ultramicroscopic investigation. With the introduction of electron microscopic techniques, we have been able to confirm many light microscopic studies in pathological corneas. This contribution has been most valuable in the identification of the sites and types of pathological changes in corneal dystrophies and degenerations. This review of electron microscopic studies describes the present concepts on the nature of the histological changes in dystrophies and degenerations of the anterior and posterior corneal layers and corneal stroma. It also includes a review of some corneal inflammatory conditions as well as metabolic disorders affecting its transparency.

Amyloidosis↗
PubMedDate not supplied

[Phakoemulsification using the Girard apparatus. Experimental study of the effects on the corneal endothelium of the rabbit].

The purpose of this paper was to investigate the potential alterations of the corneal endothelium following phacofragmentation with the Girard Ultrasonic Phacofragmentation Unit. The study was done in rabbit corneas using the specular microscope, nitroblue tetrazoium staining, and scanning electron microscopy. The perfusion fluid was Plasmalyte 148 R (Travenol), a solution which has been previously evaluated in this type of operation. Two experiments were done: (1) The effects of ultra-sound and irrigation for a period of three minutes, and (2) The effect of phacofragmentation for an average time of ten minutes. Results of the first experiment showed no cell destruction, but increased permeability to nitroblue tetrazolium. The second study showed areas of isolated or confluent cell destruction probably caused by mechanical trauma due to instrumentation or by lens nucleus rubbing against the corneal endothelium. These lesions have been observed with other instruments in similar techniques of lens removal.

Animals↗
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The effect of a new intraocular irrigating solution containing dextran on rabbit corneal endothelium.

This study investigated the effect of a balanced salt solution for intraocular irrigation containing 2% dextran 40. The effect of this solution was compared to that of a normal saline solution (0.9%) and balanced salt solution (Alcon). Following incubation of rabbit corneas for up to 72 h at 4 degrees C, the incubated corneas were studied by staining with Nitroblue Tetrazolium and by scanning electron microscopy. Insignificant changes occurred during the first 24 h of incubation. However, corneas stored in the dextran containing solution showed slightly smaller endothelial cells with tight junctions after 72 h. Endothelial cells showed progressive membrane rupture and eventual disappearance when incubated in normal saline for over 24 h at 4 degrees C.

Animals↗
PubMedDate not supplied

Keratoplasty and intraocular lenses.

This paper describes the surgical results in 163 patients in whom intraocular lenses (IOL) had been implanted, exchanged, or removed during penetrating keratoplasty (PKP). They were divided into the following groups: PKP, cataract extraction, and IOL implant; PKP in aphakia and IOL implant; PKP and IOL exchange; PKP and IOL removal. In all groups clear transplants were obtained in over 92% of the cases, with best optical and visual results obtained in cases of Fuchs' dystrophy with cataract extraction and IOL implant (98% clear grafts and vision better than 20/40 in most cases). There were no significant differences in graft transparency and in the magnitude of visual acuity improvement between cases of pseudophakic edema with IOL replaced or removed at the time of surgery, and cases of aphakic edema with secondary IOL implant. Good surgical results are attributed to the use of young donor tissue with short time of storage, microsurgical techniques, and the use of sodium hyaluronate (Healon) for the protection of graft endothelium.

Aged↗