Microvascular cerebral blood volume changes in aging APPswe/PS1dE9 AD mouse model: a voxel-wise approach

Vascular disorders can either be cause or consequence in the pathophysiology of Alzheimer’s disease (AD). To comprehensively characterize the occurrence of vascular impairment in a double transgenic mouse model for AD (APP_swe/PS1_dE9) during aging, we developed a new method to obtain microvascular relative cerebral blood volume (rCBV_micro) maps from gradient echo MR imaging by histogram evaluation and we applied a voxel-wise approach to detect rCBV_micro changes. With this methodology the development of cerebral microvascular impairments can be described in vivo with 0.16 mm isotropic resolution for the whole mouse brain. At 8 months, impaired rCBV_micro appeared in some cortical regions and in the thalamus, which spreads over several sub-cortical areas and the hippocampus at 13 months. With a ROI-based approach, we further showed that hippocampal rCBV_micro in 13-month-old wild-type and APP_swe/PS1_dE9 mice correlates well with capillary density measured with immunohistochemical staining. However, no differences in capillary density were detected between genotypes. The rCBV_micro values showed no significant correlation with amyloid-β (Aβ) plaque deposition, Aβ at blood vessel walls and biochemically measured levels of Aβ_1-40, Aβ_1-42 oligomers and fibrillar forms. These results suggest that rCBV_micro reduction is caused by an impaired vasoactivity of capillaries and arterioles, which is not directly correlated with the amount of Aβ deposition in parenchyma nor blood vessel walls.     

A P EDIATRIC S URVEY FOR THE N ATIONAL H IGHWAY T RAFFIC S AFETY A DMINISTRATION : E MERGENCY M EDICAL S ERVICES S YSTEM R E-ASSESSMENTS

Emergency medical services for children, or EMSC, is still a relatively underdeveloped component of most state and local EMS systems. Advocacy and funding for EMSC from the federal EMSC Program, availability of many useful EMSC products, and the rapidly enlarging literature in EMSC have created heightened awareness and interest in improving systems for pediatric emergency, trauma, and critical care. The new National Highway Traffic Safety Administration (NHTSA) EMS Technical Assistance (TA) re-assessment program, the second version of the successful original TA Program from 1988 to 1996, provides an ideal opportunity for state EMS professionals to evaluate EMSC capabilities and to integrate new EMSC products and services. The history of the TA Program reflects the evolution of EMS itself and indicates a historical inattention to children's issues, but re-assessment TA teams now have much useful intervening EMSC history to draw upon and a clear philosophical mandate to integrate children more fully in EMS system planning and management. In order to facilitate state-of-the-art reviews of EMSC within state EMS systems, a pediatric survey for the NHTSA re-assessments is presented. The survey, developed with the input of EMS administrators and physicians and approved by the National Association of State EMS Directors, follows the original ten-component model for EMS system review. It is intended for optional use within the overall EMS review process.     

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