Summary Dynamic changes in 5-methylcytosine (5mC) have been implicated in the regulation of gene expression critical for consolidation of memory. However, little is known about how these changes in 5mC are regulated in the adult brain. The enzyme Tet methylcytosine dioxygenase 1 (TET1) has been shown to promote active DNA demethylation in the nervous system. Therefore, we took a viral-mediated approach to overexpress the enzyme in the hippocampus and test its potential involvement in memory formation. We found that Tet1 is a neuronal-activity regulated gene and that its overexpression leads to changes in global modified cytosine levels. Furthermore, expression of TET1 or a catalytically inactive mutant (TET1m) resulted in the up-regulation of several neuronal memory-associated genes and impaired contextual fear memory. In summary, we show that neuronal Tet1 regulates DNA methylation levels and that its expression, independent of its catalytic activity, regulates the expression of CNS activity- dependent genes and memory formation.

In animal models, IL-12 and IL-23 participate in the development of malignant neoplasms of keratinocytes. However, the role of these cytokines in pigmented lesion development and their progression to melanoma has received little attention. IL-12p35, IL-23p19, and IL-12/IL-23p40 knockout mice on a C3H/HeN background, subjected to a melanomagenesis protocol, demonstrated profound differences in susceptibility to nevus initiation, transformation, tumorigenicity and metastatic potential. IL-23 was found to be essential for melanocyte homeostasis, whereas IL-12 supported nevus development. A direct action of IL-23 on primary melanocytes, shown to be IL-23R+, demonstrated that DNA repair of damaged melanocytes requires IL-23. Further, IL-23 modulated the cutaneous microenvironment by limiting regulatory T cells and IFNγ and inhibiting IL-10 production. Neutralizing antibody to IFNγ, but not IL-17, inhibited nevus development (p<0.01).

Cleidocranial dysplasia (CCD) is an autosomal dominant disorder that presents with skeletal dysplasia. It commonly presents with significant dental problems such as retention of multiple deciduous teeth, impaction or delay in eruption of permanent teeth, and often with the presence of supernumerary teeth. We report two cases showing clinical and radiographic features of CCD.

Package inserts include sponsored studies that overestimate the sensitivity of rapid tests to diagnose GAS pharyngitis by approximately 10%. Physicians should understand that package inserts overestimate diagnostic test utility; a negative test cannot be used to exclude GAS pharyngitis.