Our case report demonstrates safe transition from enteral naloxone to enteral methylnaltrexone in a pediatric patient, avoiding the serious consequences of relative opioid toxicity. This patient experienced significant improvement of opioid-induced constipation and reduction in opioid requirements and it is possible that other patients would benefit as well. The role of enteral methylnaltrexone deserves further investigation.

Glycine max L. Mcrr. (soybean) is an important agronomic crop grown throughout the world, investigations of the soybean genome reveal that it is an ancient polyploid. We would cxpcct duplicate functiunul genes in soybean to have arisen from the pulypluidizatioii event and to be found in homoeologous regions in the soybean genome. We mapped the duplicate functional genes Pal and Pa2 and found they were not located in directly homoeologous regions as might be expected. To determine the evolutionary origins of these genes the soybean genome was examined for additional duplications by comparisons with the related legumes Vigna radiata and Phaseolus vulgaris. These comparisons disclosed two regions in G. max showing homology to a single region in each K radiata and P. vulgaris. Comparisons of TBLASTX searches using soybean RPLP sequences and Arabidopsis thaliana genomic sequences led to the identification of regions of conservation between G. max and A. ilialiana. Detection of conserved regions also allowed us to determine that two homoeologous blocks in soybean showed homology to the same region in A. thaliana. The physical relationship of the duplicate genes mapped in soybean appears to be the result of two rounds of duplication; a recent duplication detected by comparison of duplicate RFLP markers in soybean and an earlier event only detected by the use o(A. thaliana as a bridging spccies. These results emphasize the importance in interspecies comparisons to detect evolutionary relationships of distantly related genomic segments. I CHAPTER 1. GENERAL INTRODUCTION