The effects of Vitamin D Insufficiency and Seasonal Decrease on cognition.

Background: Vitamin D3 (cholecalciferol) deficiency has been associated with dementia and cognitive decline. Which cognitive domains are most associated with D3 levels and how seasonal fluctuations in levels relate to cognition is unclear. We addressed these questions using a prospective observational study examining associations between D3 levels and cognition among individuals living in northern latitudes (54°N) in summer and winter.

Syntaxin 1A is required for normal in utero development.

We have generated a syntaxin 1A knockout mouse by deletion of exons 3 through 6 and a concomitant insertion of a stop codon in exon 2. Heterozygous knockout animals were viable with no apparent phenotype. In contrast, the vast majority of homozygous animals died in utero, with embryos examined at day E15 showing a drastic reduction in body size and development when compared to WT and heterozygous littermates.