Visual attention shifting in autism spectrum disorder

Much research to date has been devoted to understanding the neurocognitive abnormalities characteristic of autism spectrum disorders (ASD). Abnormalities in visual attention are particularly notable in ASD and have the potential to inform an understanding of the aberrant neural networks underlying this disorder. The current study utilized a model integrating components of both a two-stage model of perceptual binding and Posner\u27s model of attention in order to provide a coherent account of previous findings of both enhanced and impaired visual attention abilities in ASD. To investigate a potential deficit in attention shifting underlying a variety of observed attentional abnormalities in ASD, the present study employed experimental paradigms requiring attentional shifting at two levels of visual information processing. Aims of the current study were (1) to investigate a general deficit in shifting attention at the level of both preattention and focused attention in ASD as compared to age- and gender-matched NT controls, as measured by both a visual search task with a dimensional shift component and a Navon-type letter task requiring participants to shift attention between global and local levels of a visual stimulus; and (2) to investigate the degree to which deficits in attention shifting as measured by these tasks in ASD as compared to age- and gender-matched NT are related to social functioning. Results were not consistent with a general deficit in attention shifting, but rather showed a qualitatively similar shifting response in ASD and neurotypicals. Preliminary support was found for a relationship between measures of social functioning and attention shifting at the level of both preattention and focused attention. Hypothesized relationships with underlying neural networks and directions for future research are discussed

Gamma oscillatory activity in autism spectrum disorder during a face cueing task

Joint attention is a social interaction skill that normally develops in infancy and involves following another’s gaze to a stimulus. This skill is absent or developmentally delayed in autism spectrum disorders (ASD), causing cascading effects on development. Neural synchrony in the gamma frequency band is thought to be involved in cognitive functions such as joint attention. The current study investigated differences in gamma power between neurotypicals and ASD as measured by magnetoencephalography (MEG) while performing a gaze cueing task simulating joint attention. Results support lower frontal gamma power in ASD, suggesting that impaired generation of gamma activity in the prefrontal cortex may be involved in impairments in social cognitive functions such as joint attention in ASD. In contrast to previous research, findings did not support higher posterior gamma power in ASD, indicating a need for further research to clarify the nature of gamma oscillatory activity in posterior brain regions in ASD

The Macrophage Scavenger Receptor A Is Host-Protective in Experimental Meningococcal Septicaemia

Macrophage Scavenger Receptor A (SR-A) is a major non-opsonic receptor for Neisseria meningitidis on mononuclear phagocytes in vitro, and the surface proteins NMB0278, NMB0667, and NMB1220 have been identified as ligands for SR-A. In this study we ascertain the in vivo role of SR-A in the recognition of N. meningitidis MC58 (serogroup B) in a murine model of meningococcal septicaemia. We infected wild-type and SR-A−/− animals intraperitoneally with N. meningitidis MC58 and monitored their health over a period of 50 hours. We also determined the levels of bacteraemia in the blood and spleen, and measured levels of the pro-inflammatory cytokine interleukin-6 (IL-6). The health of SR-A−/− animals deteriorated more rapidly, and they showed a 33% reduction in survival compared to wild-type animals. SR-A−/− animals consistently exhibited higher levels of bacteraemia and increased levels of IL-6, compared to wild-type animals. Subsequently, we constructed a bacterial mutant (MC58-278-1220) lacking two of the SR-A ligands, NMB0278 and NMB1220. Mutation of NMB0667 proved to be lethal. When mice were infected with the mutant bacteria MC58-278-1220, no significant differences could be observed in the health, survival, bacteraemia, and cytokine production between wild-type and SR-A−/− animals. Overall, mutant bacteria appeared to cause less severe symptoms of septicaemia, and a competitive index assay showed that higher levels of wild-type bacteria were recovered when animals were infected with a 1∶1 ratio of wild-type MC58 and mutant MC58-278-1220 bacteria. These data represent the first report of the protective role of SR-A, a macrophage-restricted, non-opsonic receptor, in meningococcal septicaemia in vivo, and the importance of the recognition of bacterial protein ligands, rather than lipopolysaccharide

Neural Synchrony Examined with Magnetoencephalography (MEG) During Eye Gaze Processing in Autism Spectrum Disorders: Preliminary Findings

Gaze processing deficits are a seminal, early, and enduring behavioral deficit in autism spectrum disorder (ASD); however, a comprehensive characterization of the neural processes mediating abnormal gaze processing in ASD has yet to be conducted. This study investigated whole-brain patterns of neural synchrony during passive viewing of direct and averted eye gaze in ASD adolescents and young adults (M Age  = 16.6) compared to neurotypicals (NT) (MAge  = 17.5) while undergoing magnetoencephalography. Coherence between each pair of 54 brain regions within each of three frequency bands (low frequency (0 to 15 Hz), beta (15 to 30 Hz), and low gamma (30 to 45 Hz)) was calculated

Neural Synchrony Examined with Magnetoencephalography (MEG) During Eye Gaze Processing in Autism Spectrum Disorders: Preliminary Findings

Gaze processing deficits are a seminal, early, and enduring behavioral deficit in autism spectrum disorder (ASD); however, a comprehensive characterization of the neural processes mediating abnormal gaze processing in ASD has yet to be conducted. This study investigated whole-brain patterns of neural synchrony during passive viewing of direct and averted eye gaze in ASD adolescents and young adults (M Age  = 16.6) compared to neurotypicals (NT) (MAge  = 17.5) while undergoing magnetoencephalography. Coherence between each pair of 54 brain regions within each of three frequency bands (low frequency (0 to 15 Hz), beta (15 to 30 Hz), and low gamma (30 to 45 Hz)) was calculated

Comparative performance of bone char-based filters for the removal of fluoride from drinking water

There is a great need for effective, reliable and inexpensive filters for the removal of fluoride for the millions of people affected in low and middle-income countries. This paper compares field and laboratory performance of bone char (BC) filters and filters, known as contact precipitation (CP), based on a combination of bone char and calcium-phosphate pellets

Trypanosoma brucei aquaglyceroporin 2 is a high-affinity transporter for pentamidine and melaminophenyl arsenic drugs and the main genetic determinant of resistance to these drugs.

OBJECTIVES: Trypanosoma brucei drug transporters include the TbAT1/P2 aminopurine transporter and the high-affinity pentamidine transporter (HAPT1), but the genetic identity of HAPT1 is unknown. We recently reported that loss of T. brucei aquaglyceroporin 2 (TbAQP2) caused melarsoprol/pentamidine cross-resistance (MPXR) in these parasites and the current study aims to delineate the mechanism by which this occurs. METHODS: The TbAQP2 loci of isogenic pairs of drug-susceptible and MPXR strains of T. brucei subspecies were sequenced. Drug susceptibility profiles of trypanosome strains were correlated with expression of mutated TbAQP2 alleles. Pentamidine transport was studied in T. brucei subspecies expressing TbAQP2 variants. RESULTS: All MPXR strains examined contained TbAQP2 deletions or rearrangements, regardless of whether the strains were originally adapted in vitro or in vivo to arsenicals or to pentamidine. The MPXR strains and AQP2 knockout strains had lost HAPT1 activity. Reintroduction of TbAQP2 in MPXR trypanosomes restored susceptibility to the drugs and reinstated HAPT1 activity, but did not change the activity of TbAT1/P2. Expression of TbAQP2 sensitized Leishmania mexicana promastigotes 40-fold to pentamidine and >1000-fold to melaminophenyl arsenicals and induced a high-affinity pentamidine transport activity indistinguishable from HAPT1 by Km and inhibitor profile. Grafting the TbAQP2 selectivity filter amino acid residues onto a chimeric allele of AQP2 and AQP3 partly restored susceptibility to pentamidine and an arsenical. CONCLUSIONS: TbAQP2 mediates high-affinity uptake of pentamidine and melaminophenyl arsenicals in trypanosomes and TbAQP2 encodes the previously reported HAPT1 activity. This finding establishes TbAQP2 as an important drug transporter

Implementation of adolescent family-based substance use prevention programs in health care settings: Comparisons across conditions and programs

The majority of knowledge related to implementation of family-based substance use prevention programs is based on programs delivered in school and community settings. The aim of this study is to examine procedures related to implementation effectiveness and quality of two family-based universal substance use prevention programs delivered in health care settings, the Strengthening Families Program: For Parents and Youth 10–14 (SFP) and Family Matters (FM). These evidence-based programs were delivered as part of a larger random control intervention study designed to assess the influence of program choice vs. assignment on study participation and adolescent substance use outcomes. We also assess the effects of program choice (vs. assignment to program) on program delivery