No abstract

EDITOR'S NOTEThe E'xecutive Board of the Division for Early Childhood will at times approve position papers related to topics of interest to the field. Beginning with this issue, such papers will be published in the joumal. Comments or concems about the papers should be communicated to the chairof the committee preparing the paperorlhe president of the Division forEarly ChiIdhood. OVERVIEW This position paper contains recommendations for the certification of early childhood special educators who will be employed in early intervention programs serving children with special needs from birth through five and their families. These recommendations represent an approach to creating a certification structure that, in the view of the Division for Early Childhood, Council for Exceptional Children, will ensure a minimum level of beginning and continuing professional competence within the discipline of Early Childhood Special Education. The primary features of these recommendations are: (a) creation of a certificate in Early Childhood Special Education, to cover the birth-5 age range; (b) a 2-level certification structure to include a Beginning Professional Certificate and a Continuing Professional Certificate, with the former being a generalist certificate covering the birth-5 range and the latter a specialist certificate focused on either the infant/toddler or preschool level; (c) specific content areas at Univ of Connecticut / Health Center / Library on June 13, 2015 jei.sagepub.com Downloaded from 196 that are considered essential for early childhood special educators' working with young children with special needs and their families, supporting the unique contributions of this discipline to early intervention systems, and (d) a structure that ensures continued professional development.The first section reviews issues that were considered and that contributed to the positions taken in this paper. The second section contains specific recommendations for establishing a certificate in this area. An elaboration of content areas listed as a part of these recommendations may be found inThis position paper is not intended to be mandatory. Its purpose is to provide guidance to states as they develop personnel standards for early childhood special educators. Individual circumstances within each state will require flexible use of these guidelines. BACKGROUND

) has been inserted into nucleoside transport-deficient S49 cells. Two classes of mutants expressing this nucleobase permease were generated. The first, as exemplified by the AE1HADPAB2 cell line, possessed an augmented capacity to transport low concentrations of the three purine bases, hypoxanthine, guanine, and adenine. The second class of mutants, as typified by the AE1HADPAB5 clone, possessed an augmented capability to translocate low levels of hypoxanthine and guanine, but not adenine. Neither the AE,HADPAB2nor the AE1HADPAB5 cells could transport nucleosides, suggesting that the expression of the high-affinity base transporter did not reverse the mutation in the nucleoside transport system.

The single nucleoside transport function of mouse S49 lymphoblasts also transports purine bases (B. Aronow and B. Ullman, J. Biol. Chem. 261:2014Chem. 261: -2019Chem. 261: , 1986). This transport of purine bases by S49 cells is sensitive to inhibition by dipyridamole (DPA) and 4-nitrobenzylthioinosine, two potent inhibitors of nucleoside transport. Therefore, wild-type S49 cells cannot salvage low hypoxanthine concentrations in the presence of 10 ,uM DPA and 11 ,uM azaserine; the latter is a potent inhibitor of purine biosynthesis. Among a mutagenized wild-type population, a cell line, JPA2, was isolated which could proliferate in 50 ,M hypoxanthine-11 ,uM azaserine-10 M DPA. The basis for the survival of JPA2 cells under these selective conditions was expression of a unique, high-affinity purine nucleobase transport function not present in wild-type cells. JPA2 cells could transport 5 ,uM concentrations of hypoxanthine, guanine, and adenine 15-to 30-fold more efficiently than parental cells did. Kinetic analyses revealed that the affinity of the JPA2 transporter for all three purine bases was much greater than that of the wild-type nucleobase transport system. Moreover, nucleobase transport in JPA2 cells, unlike that in parental cells, was insensitive to inhibition by DPA, 4-nitrobenzylthioinosine, sulfhydryl reagents, and nucleosides. No alterations in nucleoside transport capability, phosphoribosylpyrophosphate levels, or purine phosphoribosyltransferase enzymes were detected in JPA2 cells. Thus, JPA2 cells express a novel nucleobase transport capability which can be distinguished from the nucleoside transport function by multiple biochemical parameters.

No abstract