Barriers and facilitators to implementation of developmental screening and early intervention in Canadian organizations following completion of a training and coaching model: a thematic analysis.

Introduction: Developmental delay affects approximately 1 in 4 children under 6 years old. Developmental delay can be detected using validated developmental screening tools, such as the Ages and Stages Questionnaires. Following developmental screening, early intervention can occur to address and support any developmental areas of concern.

Glycosylation of PrPC determines timing of neuroinvasion and targeting in the brain following transmissible spongiform encephalopathy infection by a peripheral route.

Transmissible spongiform encephalopathy (TSE) infectivity naturally spreads from site of entry in the periphery to the central nervous system where pathological lesions are formed. Several routes and cells within the host have been identified as important for facilitating the infectious process. Expression of the glycoprotein cellular PrP (PrP(C)) is considered a key factor for replication of infectivity in the central nervous system (CNS) and its transport to the brain, and it has been suggested that the infectious agent propagates from cell to cell via a domino-like effect.

Dramatic reduction of PrP C level and glycosylation in peripheral nerves following PrP knock-out from Schwann cells does not prevent transmissible spongiform encephalopathy neuroinvasion.

Expression of the prion protein (PrP(C)) is a requirement for host susceptibility to the transmissible spongiform encephalopathies (TSEs) and thought to be necessary for the replication and transport of the infectious agent. The mechanism of TSE neuroinvasion is not fully understood, although the routing of infection has been mapped through the peripheral nervous system (PNS) and Schwann cells have been implicated as a potential conduit for transport of the TSE infectious agent. To address whether Schwann cells are a requirement for spread of the TSE agent from the site of infection to the CNS, PrP(C) expression was selectively removed from Schwann cells in vivo.

Host PrP glycosylation: a major factor determining the outcome of prion infection.

The expression of the prion protein (PrP) is essential for transmissible spongiform encephalopathy (TSE) or prion diseases to occur, but the underlying mechanism of infection remains unresolved. To address the hypothesis that glycosylation of host PrP is a major factor influencing TSE infection, we have inoculated gene-targeted transgenic mice that have restricted N-linked glycosylation of PrP with three TSE strains. We have uniquely demonstrated that mice expressing only unglycosylated PrP can sustain a TSE infection, despite altered cellular location of the host PrP.

Predicting susceptibility and incubation time of human-to-human transmission of vCJD.

Background: Identification of possible transmission of variant Creutzfeldt-Jakob disease (vCJD) via blood transfusion has caused concern over spread of the disease within the human population. We aimed to model iatrogenic spread to enable a comparison of transmission efficiencies of vCJD and bovine spongiform encephalopathy (BSE) and an assessment of the effect of the codon-129 polymorphism on human susceptibility.

Methods: Mice were produced to express human or bovine prion protein (PrP) by direct replacement of the mouse PrP gene.