A-02 Concussion at One-Year Post-Injury and Anxiety Do Not Predict Head Protective and Jump Landing Functional Reaction Time

Purpose: Individuals with a concussion history are more likely to sustain subsequent concussions and/or musculoskeletal injuries. Underlying mechanisms are unclear; reaction time (RT) deficits associated with anxiety may play an important role. The primary aim of this study was to determine if anxiety and recent concussion history predict functional RT (i.e., head protective, jump landing) under single and dual-task conditions. Methods: 40 participants (concussion:healthy = 20:20; time since concussion = 11.8 months) completed the State–Trait Anxiety Inventory, anxiety ratings before and after each task, and performed RT tasks. We used a virtual reality environment and motion capture laboratory to collect RTs for head protective and jump landing, respectively. Participants completed assessments under both single-task (i.e., “Focus solely on completing the task as quickly as possible”) and dual-task (i.e., “Subtract as quickly and accurately as possible as you await your visual stimulus”) conditions. Instructions gave equal weight to speed and accuracy. All RTs were calculated (ms) as the time from visual onset of stimuli to first movement ≥3 cm of hands (head protective) or sacral body (jump landing). A series of linear regression models determined if the independent variables predicted RTs. Results: Regression models did not explain a significant proportion of the variance in head protective (single- R2 = 0.05; p = 0.78; dual- R2 = 0.09; p = 0.49), or jump landing (single- R2 = 0.21; p = 0.08; dual- R2 = 0.12; p = 0.32) RTs. Conclusions: In a low anxiety sample, recent concussion history and anxiety do not predict clinical or functional reaction times at twelve-months post-concussion. If these differences exist, they are likely resolved by this time.

Detecting Sandbagging Performance on CNS Vital Signs Concussion Baseline Testing

Purpose

To determine CNS Vital Signs validity indicator accuracy in detecting coached suboptimal performance (i.e. sandbagging) on neurocognitive testing.

Methods

Fifty college-aged students (age=20.8–1.1 years, range 18–25) were randomly assigned to two groups of 25. We compared neurocognitive test performance for two groups completing CNS Vital Signs instructed through verbal scripts to either (1) try their best (control) or (2) purposely sandbag. Participants rated their effort after completing neurocognitive testing on a Visual Analog Scale (0mm=no effort, 100mm=maximum effort). A one-way MANOVA was used to determine domain score differences between the control and sandbagging groups (alpha=0.05) and percent flagged as invalid. A series of ANOVA’s was used to post-hoc the MANOVA.

Results

Significant raw domain score group differences were identified (V=0.67, F=7.13, p<0.001) such that the sandbagging group performed significantly worse on visual memory, psychomotor speed, reaction time, complex attention, cognitive flexibility, processing speed, executive function, and motor speed compared to the control group. Built-in CNS Vital Signs invalidity indicators successfully identified approximately 70% (17/25) of coached sandbaggers. Approximately 12% of control group participants (3/25) fell below the validity cutoff for simple attention despite instructions to perform their best. All participants on average reported less than optimal effort (mean= 6.8–2.5).

Conclusion

Built-in CNS Vital Signs validity indicators do an overall good job at identifying those attempting to purposefully sandbag the test. Given that 30% of intentional sandbaggers went undetected, clinicians should consider additional safeguards beyond test algorithms to detect these individuals at baseline.

A novel therapy, using Ghrelin with pegylated G-CSF, inhibits brain hemorrhage from ionizing radiation or combined radiation injury

Medical treatment becomes challenging when complicated injuries arise from secondary reactive metabolic and inflammatory products induced by initial acute ionizing radiation injury (RI) or when combined with subsequent trauma insult(s) (CI). With such detrimental effects on many organs, CI exacerbates the severity of primary injuries and decreases survival. Previously, in a novel study, we reported that ghrelin therapy significantly improved survival after CI. This study aimed to investigate whether brain hemorrhage induced by RI and CI could be inhibited by ghrelin therapy with pegylated G-CSF (i.e., Neulasta®, an FDA-approved drug). B6D2F1 female mice were exposed to 9.5 Gy 60Co-γ-radiation followed by 15% total-skin surface wound. Several endpoints were measured at several days. Brain hemorrhage and platelet depletion were observed in RI and CI mice. Brain hemorrhage severity was significantly higher in CI mice than in RI mice. Ghrelin therapy with pegylated G-CSF reduced the severity in brains of both RI and CI mice. RI and CI did not alter PARP and NF-κB but did significantly reduce PGC-1α and ghrelin receptors; the therapy, however, was able to partially recover ghrelin receptors. RI and CI significantly increased IL-6, KC, Eotaxin, G-CSF, MIP-2, MCP-1, MIP-1α, but significantly decreased IL-2, IL-9, IL-10, MIG, IFN-γ, and PDGF-bb; the therapy inhibited these changes. RI and CI significantly reduced platelet numbers, cellular ATP levels, NRF1/2, and AKT phosphorylation. The therapy significantly mitigated these CI-induced changes and reduced p53-mdm2 mediated caspase-3 activation. Our data are the first to support the view that Ghrelin therapy with pegylated G-CSF is potentially a novel therapy for treating brain hemorrhage after RI and CI.

Vascular function and short-term exposure to fine particulate air pollution

Exposure to fine particulate air pollution has been implicated as a risk factor for cardiopulmonary disease and mortality. Proposed biological pathways imply that particle-induced pulmonary and systemic inflammation play a role in activating the vascular endothelium and altering vascular function. Potential effects of fine particulate pollution on vascular function are explored using controlled chamber exposure and uncontrolled ambient exposure. Research subjects included four panels with a total of 26 healthy nonsmoking young adults. On two study visits, at least 7 days apart, subjects spent 3 hr in a controlled-exposure chamber exposed to 150-200 microg/m3 of fine particles generated from coal or wood combustion and 3 hr in a clean room, with exposure and nonexposure periods alternated between visits. Baseline, postexposure, and post-clean room reactive hyperemia-peripheral arterial tonometry (RH-PAT) was conducted. A microvascular responsiveness index, defined as the log of the RH-PAT ratio, was calculated. There was no contemporaneous vascular response to the few hours of controlled exposure. Declines in vascular response were associated with elevated ambient exposures for the previous 2 days, especially for female subjects. Cumulative exposure to real-life fine particulate pollution may affect vascular function. More research is needed to determine the roles of age and gender, the effect of pollution sources, the importance of cumulative exposure over a few days versus a few hours, and the lag time between exposure and response.

IAR3 encodes an auxin conjugate hydrolase from Arabidopsis

Amide-linked conjugates of indole-3-acetic acid (IAA) are putative storage or inactivation forms of the growth hormone auxin. Here, we describe the Arabidopsis iar3 mutant that displays reduced sensitivity to IAA-Ala. IAR3 is a member of a family of Arabidopsis genes related to the previously isolated ILR1 gene, which encodes an IAA-amino acid hydrolase selective for IAA-Leu and IAA-Phe. IAR3 and the very similar ILL5 gene are closely linked on chromosome 1 and comprise a subfamily of the six Arabidopsis IAA-conjugate hydrolases. The purified IAR3 enzyme hydrolyzes IAA-Ala in vitro. iar 3 ilr1 double mutants are more resistant than either single mutant to IAA-amino acid conjugates, and plants overexpressing IAR3 or ILR1 are more sensitive than is the wild type to certain IAA-amino acid conjugates, reflecting the overlapping substrate specificities of the corresponding enzymes. The IAR3 gene is expressed most strongly in roots, stems, and flowers, suggesting roles for IAA-conjugate hydrolysis in those tissues.

Putative cytoplasmic amphiphilic domains in the nerve growth factor/tumour necrosis factor receptor superfamily

Potential alpha-helical regions in cytoplasmic domains of the NGF/TNF receptor superfamily were searched to identify amphiphilic sequences favouring association with membrane surfaces, analogous to the predicted secondary structure of mastoparan (MP). Similar to MP, NGFR (rat, chick, human), human TNFR-1, and human 4-1BB have domains with putative surface membrane associating sequences. The circular dichroism spectra of mastoparan and a peptide homologous to the putative amphiphilic domain of NGFR were identical in an aqueous milieu, and both adopted an alpha-helical conformation in trifluoroethanol.