Down Syndrome and Alzheimer's Disease: Issues and Implications for Social Work Practice.

Owing to recent medical advancements, people with Down Syndrome (DS) are now able to live considerably longer lives and thus experience a variety of complex issues as they age. Alzheimer's Disease (AD) frequently occurs in older adults who have DS, but few practice guidelines exist to inform social work practice with older adults who have this dual diagnosis. This commentary will highlight the connection between these two conditions within a neurobiological framework and discuss implications for practice based on the available literature on this intersection of ability status, cognitive status, and age.

Exploring the potential of the vitamin B12 derivative azidocobalamin to undergo Huisgen 1,3-dipolar azide-alkyne cycloaddition reactions.

There is considerable interest in using the metalloprotein cofactor vitamin B12 as a vehicle to deliver drugs and diagnostic agents into mammalian or bacterial cells by exploiting the B12-specific active uptake pathways. Conjugation of the cargo via the ß-axial site or the 5'-OH of the ribose of the nucleotide are the most desirable sites, to maximise intracellular uptake. Herein we show the potential of conjugation at the beta-azido ligand of the vitamin B12 derivative azidocobalamin via a click-type azide-alkyne 1,3-dipolar cycloaddition (Huisgen cycloaddition) reaction. Reacting azidocobalamin with dimethyl acetylenedicarboxylate at 40 °C results in essentially stoichiometric conversion of azidocobalamin to the corresponding triazolato complex. The stability of the complex as a function of pH and in the presence of cyanide were investigated. The complex is stable in pD 7.0 phosphate buffer for 24 h. The rate of beta-axial ligand substitution was found to be one order of magnitude slower for the triazolatocobalamin complex compared with azidocobalamin.