Precursors of the peptide hormone gastrin stimulate proliferation in the colorectal mucosa and promote the development of colorectal carcinoma. Gastrins bind two ferric ions selectively and with high affinity, and the biological activity of glycine-extended gastrin (Ggly) in vitro is dependent on the presence of ferric ions. The aim of the present study was to determine whether or not iron is required for biological activity of progastrin and Ggly in vivo. Rats that had undergone a colostomy were infused with Ggly, and proliferation was measured in the defunctioned rectal mucosa. Proliferation was also measured in the colonic mucosa of hGAS and MTI-Ggly mice, which, by definition, overexpress progastrin and Ggly, respectively. The requirement for iron was assessed by thrice-weekly injection of the chelating agent desferrioxamine (DFO). The proliferation index in the defunctioned rectal mucosa was significantly increased in the Ggly-infused rats, and the increase was significantly reduced after treatment with DFO. Treatment with DFO significantly reduced the crypt height and proliferation index in the colonic mucosa of hGAS and MTI-Ggly mice but had no effect on the same variables in wild-type mice. These observations are consistent with the hypothesis that the biological activity of progastrin and Ggly in vivo is dependent on the presence of ferric ions and further suggest that chelating agents may block the stimulatory effects of gastrin precursors in the development of colorectal carcinoma.

Background: Special needs dentistry is in its infancy compared to other dental specialties. Continuity of care through transition from paediatric to adult dental care providers is unknown. This study seeks to determine the nature of transition practices adopted by paediatric and special needs (SN) specialists practising throughout Australia. Methods: A survey was sent to all paediatric and SN specialist dentists in Australia to determine the nature of current transition practices for paediatric SN patients in Australia. Two subsequent mail-outs were sent to non-responders. Results: Forty-nine specialist dentists registered across Australia completed the survey, of which 35 (71%) were paediatric dentists and 14 (29%) were SN dentists. Both paediatric and SN dentists treated patients over the age of 18. Of the total paediatric dentists who had transition discussions with their paediatric patients and their families, the majority (over 80%) discussed treatment options available as part of future oral care management. Paediatric dentists identified level of independence and financial situations as the most significant barrier for transition. Conclusions: Key factors exist that should be discussed with SN patients and their parents and/or guardians in order to enhance the prospect of sustained dental care into adulthood.

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