Meta‐analysis of digital game and study characteristics eliciting physiological stress responses

Digital games have been used as stressors in a range of disciplines for decades. Nonetheless, the underlying characteristics of these stressors and the study in which the stressor was applied are generally not recognized for their moderating effect on the measured physiological stress responses. We have therefore conducted a meta‐analysis that analyzes the effects of characteristics of digital game stressors and study design on heart rate, systolic and diastolic blood pressure, in studies carried out from 1976 to 2012. In order to assess the differing quality between study designs, a new scale is developed and presented, coined reliability of effect size. The results show specific and consistent moderating functions of both game and study characteristics, on average accounting for around 43%, and in certain cases up to 57% of the variance found in physiological stress responses. Possible cognitive and physiological processes underlying these moderating functions are discussed, and a new model integrating these processes with the moderating functions is presented. These findings indicate that a digital game stressor does not act as a stressor by virtue of being a game, but rather derives its stressor function from its characteristics and the methodology in which it is used. This finding, together with the size of the associated moderations, indicates the need for a standardization of digital game stressors.     

Topographic recordings of auditory evoked potentials to speech: Subcortical and cortical responses

Topographies of speech auditory brainstem response (speech ABR), a fine electrophysiological marker of speech encoding, have never been described. Yet, they could provide useful information to assess speech ABR generators and better characterize populations of interest (e.g., musicians, dyslexics). We present here a novel methodology of topographic speech ABR recording, using a 32‐channel low sampling rate (5 kHz) EEG system. Quality of speech ABRs obtained with this conventional multichannel EEG system were compared to that of signals simultaneously recorded with a high sampling rate (13.3 kHz) EEG system. Correlations between speech ABRs recorded with the two systems revealed highly similar signals, without any significant difference between their signal‐to‐noise ratios (SNRs). Moreover, an advanced denoising method for multichannel data (denoising source separation) significantly improved SNR and allowed topography of speech ABR to be recovered.     

Cuprizone‐induced demyelination and demyelination‐associated inflammation result in different proton magnetic resonance metabolite spectra

Conventional MRI is frequently used during the diagnosis of multiple sclerosis but provides only little additional pathological information. Proton MRS (¹H‐MRS), however, provides biochemical information on the lesion pathology by visualization of a spectrum of metabolites. In this study we aimed to better understand the changes in metabolite concentrations following demyelination of the white matter. Therefore, we used the cuprizone model, a well‐established mouse model to mimic type III human multiple sclerosis demyelinating lesions. First, we identified CX₃CL1/CX₃CR1 signaling as a major regulator of microglial activity in the cuprizone mouse model. Compared with control groups (heterozygous CX₃CR1^+/? C57BL/6 mice and wild type CX₃CR1^+/+ C57BL/6 mice), microgliosis, astrogliosis, oligodendrocyte cell death and demyelination were shown to be highly reduced or absent in CX₃CR1^?/? C57BL/6 mice. Second, we show that ¹H‐MRS metabolite spectra are different when comparing cuprizone‐treated CX₃CR1^?/? mice showing mild demyelination with cuprizone‐treated CX₃CR1^+/+ mice showing severe demyelination and demyelination‐associated inflammation. Following cuprizone treatment, CX₃CR1^+/+ mice show a decrease in the Glu, tCho and tNAA concentrations as well as an increased Tau concentration. In contrast, following cuprizone treatment CX₃CR1^?/? mice only showed a decrease in tCho and tNAA concentrations. Therefore, ¹H‐MRS might possibly allow us to discriminate demyelination from demyelination‐associated inflammation via changes in Tau and Glu concentration. In addition, the observed decrease in tCho concentration in cuprizone‐induced demyelinating lesions should be further explored as a possible diagnostic tool for the early identification of human MS type III lesions. Copyright © 2015 John Wiley & Sons, Ltd.     

High-Level Pan-Azole-Resistant Aspergillosis

High-level pan-azole-resistant Aspergillus fumigatus was recovered from four patients with chronic lung disease. In one patient, the development of progressive resistance followed long-term azole therapy and switching between antifungal azoles. The high-level pan-azole-resistant phenotypes were not associated with a specific cyp51A gene mutation. New strategies that avoid the development of progressive azole resistance are needed.     

Diagnosing Rhodococcus equi Infections in a Setting Where Tuberculosis Is Highly Endemic: a Double Challenge

Rhodococcus equi infection is increasing in regions with high HIV prevalence worldwide. The microbiological features and clinical mimicry of tuberculosis infection pose diagnostic challenges in high-tuberculosis-incidence settings. We present two HIV-associated cases of R. equi infection from Vietnam and discuss the unique diagnostic challenges in such settings.     

Analytical Comparison of In Vitro-Spiked Human Serum and Plasma for PCR-Based Detection of Aspergillus fumigatus DNA: a Study by the European Aspergillus PCR Initiative

The use of serum or plasma for Aspergillus PCR testing facilitates automated and standardized technology. Recommendations for serum testing are available, and while serum and plasma are regularly considered interchangeable for use in fungal diagnostics, differences in galactomannan enzyme immunoassay (GM-EIA) performance have been reported and are attributed to clot formation. Therefore, it is important to assess plasma PCR testing to determine if previous recommendations for serum are applicable and also to compare analytical performance with that of serum PCR. Molecular methods testing serum and plasma were compared through multicenter distribution of quality control panels, with additional studies to investigate the effect of clot formation and blood fractionation on DNA availability. Analytical sensitivity and time to positivity (TTP) were compared, and a regression analysis was performed to identify variables that enhanced plasma PCR performance. When testing plasma, sample volume, preextraction-to-postextraction volume ratio, PCR volume, duplicate testing, and the use of an internal control for PCR were positively associated with performance. When whole-blood samples were spiked and then fractionated, the analytical sensitivity and TTP were superior when testing plasma. Centrifugation had no effect on DNA availability, whereas the presence of clot material significantly lowered the concentration (P = 0.028). Technically, there are no major differences in the molecular processing of serum and plasma, but the formation of clot material potentially reduces available DNA in serum. During disease, Aspergillus DNA burdens in blood are often at the limits of PCR performance. Using plasma might improve performance while maintaining the methodological simplicity of serum testing.