Transcriptional Profiles for Glutamate Transporters Reveal Differences Between Organophosphates but Similarities with Unrelated Neurotoxicants

The developmental neurotoxicity of organophosphates involves mechanisms other than their shared property as cholinesterase inhibitors, among which are excitotoxicity and oxidative stress. We used PC12 cells as a neurodevelopmental model to compare the effects of chlorpyrifos and diazinon on the expression of genes encoding glutamate transporters. Chlorpyrifos had a greater effect in cells undergoing nerve growth factor-induced neurodifferentiation as compared to undifferentiated PC12 cells, with peak sensitivity at the initiation of differentiation, reflecting a global upregulation of all the glutamate transporter genes expressed in this cell line. In differentiating cells, chlorpyrifos had a significantly greater effect than did diazinon and concordance analysis indicated no resemblance in their expression patterns. At the same time, the smaller effects of diazinon were highly concordant with those of an organochlorine pesticide (dieldrin) and a metal (divalent nickel). We also performed similar evaluations for the cystine/glutamate exchanger, which provides protection against oxidative stress by moving cystine into the cell; again, chlorpyrifos had the greatest effect, in this case reducing expression in undifferentiated and differentiating cells. Our results point to excitotoxicity and oxidative stress as major contributors to the noncholinesterase mechanisms that distinguish the neurodevelopmental outcomes between different organophosphates while providing a means whereby apparently unrelated neurotoxicants may produce similar outcomes

EXAMINING RELATIONS AMONG POSITIVE AND NEGATIVE METRICS OF PSYCHOLOGICAL FLEXIBILITY AND POSITIVE AND NEGATIVE OUTCOMES OF EXPOSURE TO TRAUMA

PTSD is a mental health condition that affects many people over the course of their life (National Comorbidity Survey, 2005), including veterans (Litz & Schlenger, 2009). However, many do not experience clinical levels of distress and some experience posttraumatic growth (PTG) resulting from such an event (Tedeschi, Park, & Calhoun, 1998). The Psychological Flexibility Model, of which Acceptance and Commitment Therapy (ACT; Hayes, Strosahl, & Wilson, 1999) is based, may help explain these phenomena. The purpose of this study was to examine these relationships utilizing a measure simultaneously assessing psychological flexibility and inflexibility. It was hypothesized that psychologically inflexible behaviors would predict PTSD symptom severity, while flexible behaviors would predict PTG. Furthermore, each of psychological inflexibility and flexibility would account for unique variance in PTSD symptom severity and PTG, respectively. Finally, the domains of ACT were examined to assess the strength each component has in the maintenance of these experiences. Results indicated that both psychological inflexibility and flexibility predicted PTSD symptoms and PTG, respectively, and each predicted unique variance in these experiences. Of the individual components, cognitive fusion, experiential avoidance, inaction, and lack of contact with the present moment all contributed to PTSD symptom severity, while values clarity, lack of contact with the present moment, and present moment awareness contributed to PTG. These results suggest the psychological flexibility model overall is consistent with the experience of PTSD symptoms and the posttraumatic growth. Though further experimental methods are needed, the application of psychological flexibility through ACT could enhance PTSD treatments

Highly efficient, dual state emission from an organic semiconductor

We report highly efficient, simultaneous fluorescence and phosphorescence (74% yield) at room temperature from a single molecule ensemble of (BzP)PB dispersed into a polymer host. The slow phosphorescence (208 ms lifetime) is very efficient (50%) at room temperature and only possible because the non-radiative rate for the triplet state is extremely low. The ability of an organic molecule to function as an efficient dual state emitter at room temperature is unusual and opens new fields of applications including the use as broadband down-conversion emitters, optical sensors and attenuators, exciton probes, and spin-independent intermediates for F\"orster resonant energy transfer