Cataract surgery training using pig eyes filled with chestnuts of various hardness.

This method uses pig eyes filled with cooked chestnuts serving as pseudonuclei with the goal of teaching dividing techniques of phacoemulsification and aspiration. The pseudonuclei simulate the various degrees of human lens nuclear sclerosis. The chestnuts are trimmed to lens size. After lens extraction through a self-sealing straight incision from the pig eyes, the chestnuts are inserted in the capsular bag through the incision, which is then sutured. These preparatory procedures were initially performed by experienced surgeons but after practicing phacoemulsification technique several times, inexperienced surgeons were able to complete the entire procedure, allowing them to practice phaco chop, divide and conquer, and nondividing phacoemulsification.

A rapid, easy technique for defining detailed anatomical orientation in pre-deparaffinized tissue sections.

During our previous histochemical studies on changes in anterograde and retrograde degeneration following optic nerve transection in rats, it was necessary to make brain sections in which various bilateral components of the visual system were symmetrically included. We discovered a rapid, easy technique that defines a detailed anatomical orientation in pre-deparaffinized tissue sections. The procedure is as follows: several drops of 1% toluidine blue solution are injected with a syringe under the paraffin section on the glass slide after the sections are cut and floated on warm water. After several seconds, the staining solution is removed, and the sections are then ready to be observed under a microscope. The anatomical orientation of the section can easily be defined without deparaffinization. By controlling the condition of sectioning procedures, we could obtain bilateral symmetrical paraffin sections containing all intended components of the visual system. This method is a rapid, simple and reliable way to get tissue sections which contain all of the multiple portions on the same plane.

Platelet-derived growth factor B-chain expression in the rat retina and optic nerve: distribution and changes after transection of the optic nerve.

To test the possible involvement of platelet-derived growth factor B-chain (PDGF-B) in anterograde and retrograde degenerations of the CNS neurons, we studied the changes of PDGF-B localization and its mRNA expression in the rat retina and optic nerve (ON) after unilateral ON transection, using immunohistochemistry and in situ hybridization. In the control retinas immunoreactivity for PDGF-B and its mRNA expression were localized in the retinal ganglion cells (RGCs) and the nerve fiber layer. After ON transection PDGF-B immunoreactivity in the nerve fiber layer started to decrease on post-injury day 3 or 4. Atrophic changes in the RGCs started on day 5 just after the decrease of PDGF expression, and thereafter the RGC number decreased. In the longitudinal section of the ON rostral to the transected site, swollen axons showed intense PDGF-B immunoreactivity and macrophages, and some glial cells revealed a significant increase in both immunoreactivity and hybridization signals. Based on these findings, we hypothesized that the decrease in PDGF-B in RGCs after axotomy causes the loss of RGCs, and that increased PDGF-B expression in the ON plays a role in the cascade of tissue reactions following ON transection.