Castration eliminates conspecific aggression in group-housed CD1 male surveillance mice (Mus musculus).

Microbiologic surveillance is essential for murine health maintenance. At our institution, female progeny of inhouse-bred CD1 mice are used in both the transgenic facility and health-surveillance program. To reduce overall animal use, the male progeny, otherwise slated for euthanasia due to a lack of utility, also were enrolled as sentinels.

Prevalence of murine Helicobacter spp. Infection is reduced by restocking research colonies with Helicobacter-free mice.

Most academic research colonies of mice are endemically infected with enterohepatic Helicobacter spp. (EHS). We evaluated EHS prevalence in surveillance mice before and after a 10-y period of requiring that imported mice be free of EHS by embryo transfer rederivation or purchase from approved vendors.

Mutations in bone marrow-derived stromal stem cells unmask latent malignancy.

Neoplastic epithelia may remain dormant and clinically unapparent in human patients for decades. Multiple risk factors including mutations in tumor cells or the stromal cells may affect the switch from dormancy to malignancy. Gene mutations, including p53 mutations, within the stroma of tumors are associated with a worse clinical prognosis; however, it is not known if these stromal mutations can promote tumors in genetically at-risk tissue.