Feasibility and tolerability of ophthalmic virtual reality as a medical communication tool in children and young people.

PURPOSE: Virtual reality (VR) can be useful in explaining diseases and complications that affect children in order to improve medical communications with this vulnerable patient group. So far, children and young people's responses to high-end medical VR environments have never been assessed. METHODS: An unprecedented number of 320 children and young people were given the opportunity to interact with a VR application displaying original ophthalmic volume data via a commercially available tethered head-mounted display (HMD). Participants completed three surveys: demographics and experience with VR, usability and perceived utility of this technology and the Simulator Sickness Questionnaire. The second survey also probed participants for suggestions on improvements and whether this system could be useful for increasing engagement in science. RESULTS: A total of 206 sets of surveys were received. 165 children and young people (84 female) aged 12-18 years (mean, 15 years) completed surveys that could be used for analysis. 69 participants (47.59%) were VR-naïve, and 76 (52.41%) reported that they had previous VR experience. Results show that VR facilitated understanding of ophthalmological complications and was reasonably tolerated. Lastly, exposure to VR raised children and young people's awareness and interest in science. CONCLUSIONS: The VR platform used was successfully utilized and was well accepted in children to display and interact with volume-rendered 3D ophthalmological data. Virtual reality (VR) is suitable as a novel image display platform in ophthalmology to engage children and young people.

Lateral Pectoralis Major Muscle Flap for Axillary Defect Obliteration.

This article describes the use of a lateral pectoralis major muscle flap for preemptive obliteration of axillary defects in breast cancer patients having reconstructive surgery. The muscle flap is based on a consistent lateral branch of the pectoral component of the thoracoacromial system. The flap is useful to improve axillary contour after sentinel lymph node biopsy or axillary lymph node dissection, and to cover lymphovenous anastomoses.

Nicotine Self-Administration With Tobacco Flavor Additives in Male Rats.

INTRODUCTION: Nicotine can robustly increase responding for conditioned reinforcers (CRs), stimuli that acquire reinforcing properties based on association with primary reinforcers. Menthol and licorice are tobacco flavoring agents also found in sweet foods (eg, candy and ice cream), making them putative CRs before they are consumed in tobacco. We sought to determine if intravenous self-administration (IVSA) of nicotine was enhanced by the inclusion of oral tobacco flavor CRs. METHODS: Menthol (160 or 320 µM) or licorice root extract (0.1% or 1%) were established as CRs (paired with 20% sucrose) or "neutral" stimuli (paired with water) in separate groups. During subsequent IVSA tests, nicotine was delivered in conjunction with oral presentations of the CR. RESULTS: In experiment 1, a menthol CR significantly shifted the peak nicotine dose from 15 µg/kg/infusion (Neutral group) to 3.25 µg/kg/infusion (CR group). In experiment 2, a menthol CR significantly increased operant licks for nicotine (3 µg/kg/infusion) relative to control groups. In experiment 3, both licorice and menthol CRs significantly increased operant licks for nicotine (7.5 µg/kg/infusion) relative to an "inactive" sipper. The licorice CR increased nicotine IVSA in proportion to the strength of the flavor, but both menthol concentrations increased nicotine IVSA to a similar extent. CONCLUSION: Tobacco flavor additives with conditioned reinforcing properties promote acquisition of nicotine self-administration at low unit doses and may have robust impact on tobacco consumption when nicotine yield is low. IMPLICATIONS: Tobacco flavor additives are found in rewarding foods (eg, ice cream) and gain palatability based on associations with primary rewards (eg, sugar) making them "conditioned reinforcers." Nicotine increases the motivation for flavor conditioned reinforcers and the present studies show that tobacco flavor additives can interact with nicotine to promote more nicotine self-administration. The interaction between flavors additives and nicotine may promote nicotine exposure and subsequently dependence.

Modality differences in timing and the filled-duration illusion: Testing the pacemaker rate explanation.

Performance in temporal difference threshold and estimation tasks is markedly less accurate for visual than for auditory intervals. In addition, thresholds and estimates are likewise less accurate for empty than for filled intervals. In scalar timing theory, these differences have been explained as alterations in pacemaker rate, which is faster for auditory and filled intervals than for visual and empty intervals. We tested this explanation according to three research aims. First, we replicated the threshold and estimation tasks of Jones, Poliakoff, and Wells (Quarterly Journal of Experimental Psychology, 62, 2171-2186, 2009) and found the well-documented greater precision for auditory than visual intervals, and for filled than for empty intervals. Second, we considered inter-individual differences in these classic effects and found that up to 27% of participants exhibited opposite patterns. Finally, we examined intra-individual differences to investigate (i) whether thresholds and estimates correlate within each stimulus condition and (ii) whether the stimulus condition in which a participants' pacemaker rate was highest was the same in both tasks. Here we found that if pacemaker rate is indeed a driving factor for thresholds and estimates, its effect may be greater for empty intervals, where the two tasks correlate, than for filled intervals, where they do not. In addition, it was more common for participants to perform best in different modalities in each task, though this was not true for ordinal intra-individual differences in the filled-duration illusion. Overall, this research presents several findings inconsistent with the pacemaker rate explanation.

Regulation of glutamate transporter 1 (GLT-1) gene expression by cocaine self-administration and withdrawal.

Downregulation of the astroglial glutamate transporter GLT-1 is observed in the nucleus accumbens (NAc) following administration of multiple drugs of abuse. The decrease in GLT-1 protein expression following cocaine self-administration is dependent on both the amount of cocaine self-administered and the length of withdrawal, with longer access to cocaine and longer withdrawal periods leading to greater decreases in GLT-1 protein. However, the mechanism(s) by which cocaine downregulates GLT-1 protein remains unknown. We used qRT-PCR to examine gene expression of GLT-1 splice isoforms (GLT-1A, GLT-1B) in the NAc, prelimbic cortex (PL) and basolateral amygdala (BLA) of rats, following two widely used models of cocaine self-administration: short-access (ShA) self-administration, and the long-access (LgA) self-administration/incubation model. While downregulation of GLT-1 protein is observed following ShA cocaine self-administration and extinction, this model did not lead to a change in GLT-1A or GLT-1B gene expression in any brain region examined. Forced abstinence following ShA cocaine self-administration also was without effect. In contrast, LgA cocaine self-administration and prolonged abstinence significantly decreased GLT-1A gene expression in the NAc and BLA, and significantly decreased GLT-1B gene expression in the PL. No change was observed in NAc GLT-1A gene expression one day after LgA cocaine self-administration, indicating withdrawal-induced decreases in GLT-1A mRNA. In addition, LgA cocaine self-administration and withdrawal induced hypermethylation of the GLT-1 gene in the NAc. These results indicate that a decrease in NAc GLT-1 mRNA is only observed after extended access to cocaine combined with protracted abstinence, and that epigenetic mechanisms likely contribute to this effect.

What speeds up the internal clock? Effects of clicks and flicker on duration judgements and reaction time.

Four experiments investigated the effect of pre-stimulus events on judgements of the subjective duration of tones that they preceded. Experiments 1 to 4 used click trains, flickering squares, expanding circles, and white noise as pre-stimulus events and showed that (a) periodic clicks appeared to "speed up" the pacemaker of an internal clock but that the effect wore off over a click-free delay, (b) aperiodic click trains, and visual stimuli in the form of flickering squares and expanding circles, also produced similar increases in estimated tone duration, as did white noise, although its effect was weaker. A fifth experiment examined the effects of periodic flicker on reaction time and showed that, as with periodic clicks in a previous experiment, reaction times were shorter when preceded by flicker than without.

A Nonsense Mutation in Mycobacterium marinum That Is Suppressible by a Novel Mechanism.

Mycobacterial pathogens use the ESAT-6 system 1 (Esx-1) exporter to promote virulence. Previously, we used gene disruption and complementation to conclude that the MMAR_0039 gene in Mycobacterium marinum is required to promote Esx-1 export. Here we applied molecular genetics, proteomics, and whole-genome sequencing to demonstrate that the MMAR_0039 gene is not required for Esx-1 secretion or virulence. These findings suggest that we initially observed an indirect mechanism of genetic complementation. We identified a spontaneous nonsense mutation in a known Esx-1-associated gene which causes a loss of Esx-1 activity. We show that the Esx-1 function was restored by nonsense suppression. Moreover, we identified a polar mutation in the ppsC gene which reduced cellular impermeability but did not impact cytotoxicity in macrophages. Our studies reveal insight into Esx-1 export, nonsense suppression, and cell envelope lipid biogenesis.

Homeostasis of N-α-terminal acetylation of EsxA correlates with virulence in Mycobacterium marinum.

The mycobacterial Esx-1 (ESAT-6 system 1) exporter translocates virulence factors across the cytoplasmic membrane to the cell wall, cell surface, and the bacteriological medium in vitro. The mechanisms underlying substrate targeting to distinct locations are unknown. Several Esx-1 substrates are N-α-terminally acetylated. The role of this rare modification in bacteria is unclear. We sought to identify genes required for Esx-1 substrate modification, transport, and localization. Pathogenic mycobacteria lyse Acanthamoeba castellanii in an Esx-1-dependent manner. We conducted a genetic screen to identify Mycobacterium marinum strains which failed to lyse amoebae. We identified a noncytotoxic M. marinum strain with a transposon insertion in a predicted N-α-terminal acetyltransferase not previously linked to mycobacterial pathogenesis. Disruption of this gene led to attenuation of virulence, failure to induce a type I interferon response during macrophage infection, and loss of hemolytic activity. The major Esx-1 substrates, EsxA and EsxB, were exported to the cell surface, but only low levels were released into the bacteriological medium. The balance of EsxA N-α-terminal acetylation was disrupted, resulting in a mycobacterial strain in which surface-associated EsxA was hyperacetylated. Genetic complementation completely restored Esx-1 function and the levels of N-α-terminally acetylated EsxA on the surface but restored only low levels of Esx-1 substrates in the bacteriological medium. Our results reveal a novel gene required for mycobacterial Esx-1 export. Our findings indicate that maintaining the homeostasis of Esx-1 substrate N-α-terminal acetylation is essential for Esx-1-mediated virulence. We propose an inverse correlation between EsxA acetylation and virulence.

Correlation of phenotypic profiles using targeted proteomics identifies mycobacterial esx-1 substrates.

The Esx/WXG-100 (ESAT-6/Wss) exporters are multiprotein complexes that promote protein translocation across the cytoplasmic membrane in a diverse range of pathogenic and nonpathogenic bacterial species. The Esx-1 (ESAT-6 System-1) system mediates virulence factor translocation in mycobacterial pathogens, including the human pathogen Mycobacterium tuberculosis. Although several genes have been associated with Esx-1-mediated transport and virulence, the contribution of individual Esx-1 genes to export is largely undefined. A unique aspect of Esx-1 export is that several substrates require each other for export/stability. We exploited substrate "codependency" to identify Esx-1 substrates. We simultaneously quantified changes in the levels of 13 Esx-1 proteins from both secreted and cytosolic protein fractions generated from 16 Esx-1-deficient Mycobacterium marinum strains in a single experiment using MRM/SRM targeted mass spectrometry. This expansion of measurable Esx-1 proteins allowed us to define statistical rules for assigning novel substrates using phenotypic profiles of known Esx-1 substrates. Using this approach, we identified three additional Esx-1 substrates encoded by the esx-1 region. Our studies begin to address how disruption of specific genes affects several proteins in the Esx-1 complex. Overall, our findings illuminate relationships between Esx-1 proteins and create a framework for the identification of secreted substrates applicable to other protein exporters and pathways.

Direct detection of bacterial protein secretion using whole colony proteomics.

Bacteria use a variety of secretion systems to transport proteins beyond their cell membrane to interact with their environment. For bacterial pathogens, these systems are key virulence determinants that transport bacterial proteins into host cells. Genetic screens to identify bacterial genes required for export have relied on enzymatic or fluorescent reporters fused to known substrates to monitor secretion. However, they cannot be used in analysis of all secretion systems, limiting the implementation across bacteria. Here, we introduce the first application of a modified form of whole colony MALDI-TOF MS to directly detect protein secretion from intact bacterial colonies. We show that this method is able to specifically monitor the ESX-1 system protein secretion system, a major virulence determinant in both mycobacterial and Gram-positive pathogens that is refractory to reporter analysis. We validate the use of this technology as a high throughput screening tool by identifying an ESAT-6 system 1-deficient mutant from a Mycobacterium marinum transposon insertion library. Furthermore, we also demonstrate detection of secreted proteins of the prevalent type III secretion system from the Gram-negative pathogen, Pseudomonas aeruginosa. This method will be broadly applicable to study other bacterial protein export systems and for the identification of compounds that inhibit bacterial protein secretion.

Retrospective analysis demonstrates no advantage to operative management of distal ulna fractures.

BACKGROUND: Isolated fracture of the distal one third of the ulna (the "nightstick fracture") is a common injury no clear consensus on its optimal management. The purpose of this study is to compare the clinical outcomes of operatively and non-operatively treated distal ulna fractures. METHODS: Patients treated over a 5-year period at a level I trauma center for distal ulna fracture were identified and medical records were analyzed. Data were collected on demographics, injury mechanism, fracture pattern, type of treatment, estimated time to osseous healing, and complications. Estimated bony healing time was analyzed with the t test, and treatment types were analyzed with the chi-square test. RESULTS: Forty-seven patients with 48 ulna fractures met inclusion criteria for the study. Mean follow-up was 36 weeks. One third of the group was female and mean patient age was 43 years. Eighteen ulnas were treated operatively. There was not a significant difference in the non-operative and operative groups regarding proportions of patients with angulation greater than 15° or 25% or greater translation. There was no significant difference in time to bony consolidation. The operative group had more complications, but the rate was not significantly different than the non-operative group. CONCLUSIONS: Isolated distal ulna fractures, including those angulated greater than 15° or translated more than 25%, appear to heal well with non-operative treatment. Operative treatment of closed isolated distal ulna fractures does not appear to confer a treatment advantage when compared to non-operative treatment.