Age-Related Intraneuronal Elevation of αII-Spectrin Breakdown Product SBDP120 in Rodent Forebrain Accelerates in 3×Tg-AD Mice

Spectrins line the intracellular surface of plasmalemma and play a critical role in supporting cytoskeletal stability and flexibility. Spectrins can be proteolytically degraded by calpains and caspases, yielding breakdown products (SBDPs) of various molecular sizes, with SBDP120 being largely derived from caspase-3 cleavage. SBDPs are putative biomarkers for traumatic brain injury. The levels of SBDPs also elevate in the brain during aging and perhaps in Alzheimer’s disease (AD), although the cellular basis for this change is currently unclear. Here we examined age-related SBDP120 alteration in forebrain neurons in rats and in the triple transgenic model of AD (3×Tg-AD) relative to non-transgenic controls. SBDP120 immunoreactivity (IR) was found in cortical neuronal somata in aged rats, and was prominent in the proximal dendrites of the olfactory bulb mitral cells. Western blot and densitometric analyses in wild-type mice revealed an age-related elevation of intraneuronal SBDP120 in the forebrain which was more robust in their 3×Tg-AD counterparts. The intraneuronal SBDP120 occurrence was not spatiotemporally correlated with transgenic amyloid precursor protein (APP) expression, β-amyloid plaque development, or phosphorylated tau expression over various forebrain regions or lamina. No microscopically detectable in situ activated caspase-3 was found in the nuclei of SBDP120-containing neurons. The present study demonstrates the age-dependent intraneuronal presence of an αII-spectrin cleavage fragment in mammalian forebrain which is exacerbated in a transgenic model of AD. This novel neuronal alteration indicates that impairments in membrane protein metabolism, possibly due to neuronal calcium mishandling and/or enhancement of calcium sensitive proteolysis, occur during aging and in transgenic AD mice

When Trust Fails: The Relation Between Children’s Trust Beliefs in Peers and their Peer Interactions in a Natural Setting

One hundred and forty-nine 8–11 year-old children (86 males; M=9 years - 4 months and SD=7 months) from the UK were administered the Trust Beliefs in Peers scale and were observed in the playground over one school year. Quadratic relations were found between trust beliefs in peers and peer interaction, which varied by gender. Compared to girls with the middle range of trust beliefs, girls with very low beliefs and those with very high beliefs (a) were less accepted/ more rejected by the peer group (i.e., lower group interaction, and greater negatively received bids), (b) showed greater indi- rect aggression (engaged in and received), (c) showed greater non-engagement (i.e., being alone), and (d) showed greater concomitant distress. Compared to children with the middle range of trust beliefs, children with those extreme trust beliefs in peers demonstrated greater direct aggression (engaged in and received) and showed passive behavior (for boys only). The findings supported the conclusion that children, primarily girls, who trust peers too little and those who trust too much are at risk for psychosocial maladjustment

Computational methods for the assignment of vibrational modes in crystalline materials

In this chapter we provide a description of the computational tools used for the calculation of the terahertz absorption spectrum of a crystalline material, with a particular focus on molecular crystals. We explain using examples why it is not correct to use the normal modes of vibration of an isolated molecule to understand the vibrational spectrum of a material in the terahertz range, but that the features in this spectral region are largely related to intermolecular interactions. It is, therefore, necessary to use methods that consider the periodicity of the crystal structure. We describe the two main methods used for the calculation of the vibrational frequencies and their absorption intensities of a crystal: lattice dynamics and molecular dynamics, providing examples showing the benefits and limitations of each method