CHARACTERIZATION OF DEVELOPMENT IN MAIZE THROUGH THE USE OF MUTANTS. I. THE POLYTYPIC (Pt) AND RAMOSA-1 (ra1) MUTANTS

The origin of morphological differences attributable to mutant genes can be identified at certain switch points in the developmental pathway. The effect of the Polytypic (Pt) gene is a stimulus to meristems in the developing inflorescence to continuous initiation of differentiating structures. The most severe expression is a suppression of meristematic activity. The action of the gene is a superimposition of its effect on the normal developmental pathway. The ramosa-1 (ra₁) gene interrupts the normal sequence of events, at the switch point, which would normally result in spikelet formation, and there is produced instead a lateral branch. The response of numerous switch points in the developmental pathway of the maize inflorescence supports the conclusion that meristems are a plastic system genetically programmed at successive intervals.     

Method of Isolated Ex Vivo Lung Perfusion in a Rat Model: Lessons Learned from Developing a Rat EVLP Program

The number of acceptable donor lungs available for lung transplantation is severely limited due to poor quality. Ex-Vivo Lung Perfusion (EVLP) has allowed lung transplantation in humans to become more readily available by enabling the ability to assess organs and expand the donor pool. As this technology expands and improves, the ability to potentially evaluate and improve the quality of substandard lungs prior to transplant is a critical need. In order to more rigorously evaluate these approaches, a reproducible animal model needs to be established that would allow for testing of improved techniques and management of the donated lungs as well as to the lung-transplant recipient. In addition, an EVLP animal model of associated pathologies, e.g., ventilation induced lung injury (VILI), would provide a novel method to evaluate treatments for these pathologies. Here, we describe the development of a rat EVLP lung program and refinements to this method that allow for a reproducible model for future expansion. We also describe the application of this EVLP system to model VILI in rat lungs. The goal is to provide the research community with key information and “pearls of wisdom”/techniques that arose from trial and error and are critical to establishing an EVLP system that is robust and reproducible.