Studies aimed at understanding the interactions of different types of radiation with cellular DNA have monitored the yields of DNA dsb versus radiation quality. Several techniques have been used to measure dsb yields in mammalian cells, and these include: neutral sedimentation gradients, filter elution and more recently pulsed field gel electrophoresis techniques (PFGE). Recent developments in PFGE have allowed the measurement of both the yields and the distribution of breaks within the genome, which go part of the way to explaining the RBE values close to 1.0 previously measured using other approaches with various radiation qualities. It is clear that future studies to determine the effectiveness of radiations of differing LET must use techniques that determine both yields and distributions of dsb, and assays need to be developed to allow these measurements at biologically relevant doses.

Objective To examine trends in disparities in children’s mental health care. Data 2002–2007 Medical Expenditure Panel Survey Study design We used the Institute of Medicine (IOM) definition of healthcare disparities and estimated two-part expenditure models to examine disparity trends in any mental health care use, any outpatient care and psychotropic drug use, as well as expenditures in these three categories, conditional on use. We used two-year longitudinal panel data to determine disparities in care initiation among children with unmet need. Principal findings Assessing trends over time between 2002 and 2007, we identified that disparities persist for blacks and Latinos in receipt of any mental health care, any outpatient care, and any psychotropic drug use. Among those with positive mental health care expenditures, Latino-white disparities in overall mental health care expenditures increased over time. Among children with unmet need, significant disparities in initiation of an episode of mental health care were found, with Whites approximately twice as likely as Blacks and Latinos to initiate care. Conclusions Disparities in children’s mental health care use are persistent and driven by disparities in initiation suggesting policies to improve detection or increase initial access to care may be critical to reducing disparities.

II Study Group 3 PURPOSE. We studied the capabilities of the Argus II retinal prosthesis for guiding fine hand movement, and demonstrated and quantified guidance improvement when using the device over when not using the device for progressively less predictable trajectories. METHODS.A total of 21 patients with retinitis pigmentosa (RP), remaining vision no more than bare light perception, and an implanted Argus II epiretinal prostheses used a touchscreen to trace white paths on black backgrounds. Sets of paths were divided into three categories: right-angle/single-turn, mixedangle/single-turn, and mixed-angle/two-turn. Subjects trained on paths by using prosthetic vision and auditory feedback, and then were tested without auditory feedback, with and without prosthetic vision. Custom software recorded position and timing information for any contact that subjects made with the screen. The area between the correct path and the trace, and the elapsed time to trace a path were used to evaluate subject performance.RESULTS. For right-angle/single-turn sets, average tracing error was reduced by 63% and tracing time increased by 156% when using the prosthesis, relative to residual vision. With mixedangle/single-turn sets, error was reduced by 53% and time to complete tracing increased by 184%. Prosthesis use decreased error by 38% and increased tracing time by 252% for paths that incorporated two turns. CONCLUSIONS.Use of an epiretinal visual prosthesis can allow RP patients with no more than bare light perception to guide fine hand movement visually. Further, prosthetic input tends to make subjects slower when performing tracing tasks, presumably reflecting greater effort. (ClinicalTrials.gov number, NCT00407602.) (Invest Ophthalmol Vis Sci. 2012;53:5095-5101)

Integrating an eye tracker into the Argus II is feasible, reduces head movements in a seated localization task, and improves pointing precision.

Exposure to ionizing radiation can increase the risk of cancer, which is often characterized by genomic instability. In environmental exposures to high-LET radiation (e.g. 222Ra), it is unlikely that many cells will be traversed or that any cell will be traversed by more than one alpha particle, resulting in an in vivo bystander situation, potentially involving inflammation. Here primary human lymphocytes were irradiated with precise numbers of 3He2+ ions delivered to defined cell population fractions, to as low as a single cell being traversed, resembling in vivo conditions. Also, we assessed the contribution to genomic instability of the pro-inflammatory cytokine tumor necrosis factor alpha (TNFA). Genomic instability was significantly elevated in irradiated groups (> or = two-fold over controls) and was comparable whether cells were traversed by one or two 3He2+ ions. Interestingly, substantial heterogeneity in genomic instability between experiments was observed when only one cell was traversed. Genomic instability was significantly reduced (60%) in cultures in which all cells were irradiated in the presence of TNFA antibody, but not when fractions were irradiated under the same conditions, suggesting that TNFA may have a role in the initiation of genomic instability in irradiated cells but not bystander cells. These results have implications for low-dose exposure risks and cancer.