CHARACTERISTICS OF IMMUNOLOGICAL MEMORY IN MICE : I. SEPARATE EARLY GENERATION OF CELLS MEDIATING IGM AND IGG MEMORY TO SHEEP ERYTHROCYTES

The kinetics of the generation of primed IgM and IgG antibody-forming cell precursors, and of helper T-cell populations, were analyzed in mice whose primary responses to high and low doses of SRBC were arrested at intervals by the immunosuppressive agents cyclophosphamide monohydrate and specific antibody. The extent to which immunological memory was established in these animals before blockade of the primary response was assessed by the hemolytic plaque assay following challenge 12 wk after priming. The presence of IgG B-memory cells and T-memory cells in suppressed mice was further investigated by the transfer into these animals of syngeneic SRBC-stimulated thymocytes or anti-θ-treated spleen cells. It was found that the progenitors of secondary IgM-synthesizing cells were primed almost immediately after injection of antigen, and that early blockade of the primary response resulted in a raised IgM response after challenge. On the other hand, priming for a secondary IgG response took at least 4 days, and was dose-dependent, although helper T populations for a secondary IgG response appeared 3 days after antigen injection. It appeared that both IgM and IgG memory cells may be considered as Y cells in terms of the X-Y-Z scheme of lymphocyte activation, but that the two populations are generated at different times after exposure to antigen. The size of either Y-cell population at any given time is dependent upon the amount of antigen available to provoke differentiation to antibody-forming Z cells, and the IgM Y-cell population in particular is likely to be depleted during the course of a normal 1° response. When IgM Y cells were maintained for long periods as a result of immunosuppression, their secondary antibody response was independent of the primed T cells necessary for a secondary IgG response

A facial expression for anxiety.

Anxiety and fear are often confounded in discussions of human emotions. However, studies of rodent defensive reactions under naturalistic conditions suggest anxiety is functionally distinct from fear. Unambiguous threats, such as predators, elicit flight from rodents (if an escape-route is available), whereas ambiguous threats (e.g., the odor of a predator) elicit risk assessment behavior, which is associated with anxiety as it is preferentially modulated by anti-anxiety drugs. However, without human evidence, it would be premature to assume that rodent-based psychological models are valid for humans. We tested the human validity of the risk assessment explanation for anxiety by presenting 8 volunteers with emotive scenarios and asking them to pose facial expressions. Photographs and videos of these expressions were shown to 40 participants who matched them to the scenarios and labeled each expression. Scenarios describing ambiguous threats were preferentially matched to the facial expression posed in response to the same scenario type. This expression consisted of two plausible environmental-scanning behaviors (eye darts and head swivels) and was labeled as anxiety, not fear. The facial expression elicited by unambiguous threat scenarios was labeled as fear. The emotion labels generated were then presented to another 18 participants who matched them back to photographs of the facial expressions. This back-matching of labels to faces also linked anxiety to the environmental-scanning face rather than fear face. Results therefore suggest that anxiety produces a distinct facial expression and that it has adaptive value in situations that are ambiguously threatening, supporting a functional, risk-assessing explanation for human anxiet

Which game narratives do adolescents of different gameplay and sociodemographic backgrounds prefer? a mixed-methods analysis

OBJECTIVE: The aim of this study was to investigate which narrative elements of digital game narratives are preferred by the general adolescent population, and to examine associations with gender, socioeconomic status (SES), and gameplay frequency. Further, the study aims to discuss how results can be translated to serious digital games. MATERIALS AND METHODS: Adolescents were recruited through school to complete a survey on narrative preferences in digital games. The survey included questions on sociodemographic information, frequency of gameplay, and an open-ended question on what could be an appealing narrative for them. Data were analyzed in a mixed-methods approach, using thematic analysis and chi-square analyses to determine narrative preferences and the associations between game narrative elements and player characteristics (gender, SES, and frequency of gameplay). RESULTS: The sample consisted of 446 adolescents (12-15 years old) who described 30 narrative subthemes. Preferences included human characters as protagonists; nonhuman characters only as antagonists; realistic settings, such as public places or cities; and a strong conflict surrounding crime, catastrophe, or war. Girls more often than boys defined characters by their age, included avatars, located the narrative in private places, developed profession-related skills, and included a positive atmosphere. Adolescents of nonacademic education more often than adolescents of academic education defined characters by criminal actions. Infrequent players more often included human characters defined by their age than frequent players. After performing a Bonferroni correction, narrative preferences for several gender differences remained. CONCLUSION: Different narrative elements related to subgroups of adolescents by gender, SES, and frequency of gameplay. Customization of narratives in serious digital health games should be warranted for boys and girls; yet, further research is needed to specify how to address girls in particular

National-level schoolwork pressure, family structure, internet use, and obesity as drivers of time trends in adolescent psychological complaints between 2002 and 2018

Little is known about societal processes that contribute to changes in adolescent mental health problems. This study aims to fill this gap using data from the Health Behavior in School-aged Children study between 2002 and 2018 (ncountries = 43, nindividuals = 680,269, Mage = 14.52 (SD = 1.06), 51.04% female), supplemented with other international data. National-level psychological complaints increased more strongly among girls than boys. National-level schoolwork pressure, single-parent households, time spent on internet, and obesity were generally rising. In both boys’ and girls’ samples, increases in national-level schoolwork pressure, obesity, and time spent on internet use were independently associated with increases national-level psychological complaints. However, national-level obesity and psychological complaints were more strongly related among girls than boys. Results highlight the potential impact of societal-level processes on adolescent mental health problems

Do social support and eating family meals together play a role in promoting resilience to bullying and cyberbullying in Scottish school children?

Funding for the Scottish 2018 HBSC Survey was provided by NHS Health Scotland. This work was also supported by the MRC Mental Health Data Pathfinder Award (reference MC_PC_17217).This study investigates if cyberbullying is associated with wellbeing independently of traditional bullying and if social support and eating family meals together promotes resilience by buffering adolescents against the consequences of both types of bullying. Data for 5286 eleven, thirteen and fifteen year olds participating in the cross-sectional 2018 Scottish Health Behaviour in School-aged Children study were analysed. Adolescent self-report measures were used to assess traditional bullying, cyberbullying, classmate and teacher support and frequency of family meals together. Psychological wellbeing was assessed with the 5-item World Health Organization Wellbeing index. Analyses were conducted separately by gender with multilevel models, adjusting for sociodemographic factors. Resilience to bullying and cyberbullying was operationalised using statistical interactions. For both genders, cyberbullying and traditional bullying measures were associated with reduced wellbeing and all social support indicators were associated with increased wellbeing. In models containing both bullying measures, frequent traditional bullying victimisation was associated with a 7.2 (95% CI: 3.4–10.1) reduction in wellbeing score for boys and a 7.2 (95% CI: 4.5–10.0) reduction for girls, while cyberbullying was associated with 10.5 (95% CI: 5.8–15.1) reduction in wellbeing score for boys and 11.1 (95% CI: 6.7–15.5) reduction for girls. For both genders adjusting for classmate support explained away the relationships between traditional bullying and wellbeing, but cyberbullying was associated negatively with wellbeing independent of social support. Only one of 12 interaction tests provided any evidence of resilience. Cyberbullying was associated with a 7.8 (95% CI: 0.2–15.4) reduction in wellbeing score for girls who ate with their family every day, and 17.3 (95% CI: 10.5–24.1) reduction for girls who ate with their families less than weekly. In conclusion, cyberbullying is a strong, albeit rare, threat to adolescent wellbeing. Social support is important for wellbeing, but its ability to buffer adolescents against the consequences of bullying may be limited.Publisher PDFPeer reviewe

Do country-level environmental factors explain cross-national variation in adolescent physical activity? A multilevel study in 29 European countries

Background:  Worldwide, roughly 80% of adolescents fail to meet World Health Organization (WHO) recommendations regarding physical activity, though there is substantial variation in adolescent physical activity prevalence across countries. This study explored whether country-level environmental differences explained cross-national variation in adolescent moderate- to vigorous-intensity physical activity (MVPA) and vigorous-intensity activity (VPA). Method:  Using the data of 138,014 11- to 15-year-olds from 29 European countries in the 2013/2014 Health Behaviour in School-aged Children (HBSC) study, multilevel regression models examined the influence of four types of country-level environmental factors (physical, socio-cultural, economic, and political) on self-reported individual-level physical activity (MVPA and VPA). Results:  The environmental variables explained 38% of country-level variance in MVPA and 81% of country-level variance in VPA. Lower annual average national temperature, higher community safety, lower average national household income and a weaker physical education policy were significantly associated with more MVPA. Greater urbanisation, lower annual average national temperature, higher adult physical activity and higher average national household income were significantly associated with more VPA. Conclusions:  The findings showed that national differences in the physical, socio-cultural and economic environment were related to adolescent physical activity. They point to potential avenues for future research looking at interactions between individual and environmental factors.Publisher PDFPeer reviewe

Evidence of Early-Stage Selection on EPAS1 and GPR126 Genes in Andean High Altitude Populations.

The aim of this study is to identify genetic variants that harbour signatures of recent positive selection and may facilitate physiological adaptations to hypobaric hypoxia. To achieve this, we conducted whole genome sequencing and lung function tests in 19 Argentinean highlanders (>3500 m) comparing them to 16 Native American lowlanders. We developed a new statistical procedure using a combination of population branch statistics (PBS) and number of segregating sites by length (nSL) to detect beneficial alleles that arose since the settlement of the Andes and are currently present in 15-50% of the population. We identified two missense variants as significant targets of selection. One of these variants, located within the GPR126 gene, has been previously associated with the forced expiratory volume/forced vital capacity ratio. The other novel missense variant mapped to the EPAS1 gene encoding the hypoxia inducible factor 2α. EPAS1 is known to be the major selection candidate gene in Tibetans. The derived allele of GPR126 is associated with lung function in our sample of highlanders (p < 0.05). These variants may contribute to the physiological adaptations to hypobaric hypoxia, possibly by altering lung function. The new statistical approach might be a useful tool to detect selected variants in population studies

Association of alcohol control policies with adolescent alcohol consumption and with social inequality in adolescent alcohol consumption : a multilevel study in 33 countries and regions

Funding: The Health Behaviour in School-aged Children (HBSC) is an international study carried out in collaboration with WHO Europe. This research is funded by public sources in each member country. Specifically, ELL, CMM, and ISQ are supported by the Ministry de Health, Spain. CMM is supported by the VI Plan Propiode Investigación de la Universidad de Sevilla 2018, under the action “II.5B Contrato de acceso al Sistema Españolde Ciencia, Tecnología e Innovación para el Desarrollo del Programa Propio de I + D + i de la Universidad de Sevilla”. JI is supported by the UK Medical Research Council (MC_UU_12017/12) and the Chief Scientist Office (SPHSU12).Background  Previous research found inconsistent associations between alcohol control policies and socioeconomic inequality with adolescent drinking outcomes. This study expands the focus beyond individual associations to examine whether a combination of policies is related to socioeconomic inequality in adolescent drinking outcomes and whether this relationship varies across survey years. Methods  Multilevel modelling of 4 waves of repeat cross-sectional survey data (2001/02, 2005/06, 2009/10, and 2013/14) from the Health Behaviour in School-aged Children (HBSC) study was carried out. The sample was composed of 671,084 adolescents (51% girls) aged 11, 13, and 15 (mean age=13.58; SD=1.65) from 33 European and North American countries/regions. The dependent variables were lifetime alcohol consumption, weekly alcohol consumption, and lifetime drunkenness. Independent variables were of three types: individual-level variables (age, sex, Family Affluence Scale, and the Perceived Family Wealth), time-level variable (survey year), and context-level variables (minimum legal drinking age, physical availability, advertising restrictions, a total alcohol policy index, and affordability of alcohol). Results  The total alcohol policy index showed a negative relationship with both lifetime and weekly consumption. Higher affordability of alcohol was related to higher lifetime and weekly consumption and higher lifetime drunkenness. Family Affluence Scale was positively related to all three alcohol measures and Perceived Family Wealth was negatively related to lifetime drunkenness, with these associations increasing across survey years. The total alcohol policy index buffered the associations of Family Affluence Scale and Perceived Family Wealth with adolescent drinking outcomes. Conclusion  A combination of alcohol control policies is more effective in reducing adolescent drinking outcomes than single policy measures. Reducing the affordability of alcohol stood out as the most successful single measure. Socioeconomic inequalities (i.e. higher alcohol consumption and drunkenness in adolescents with higher family affluence and higher drunkenness in adolescents perceiving their families to be poor) have persisted and even increased across survey years. A combined alcohol control policy can help in tackling them.PostprintPublisher PDFPeer reviewe

Associations between perceived social and physical environmental variables and physical activity and screen time among adolescents in four European countries

The study was supported from European Regional Development Fund-Project “Effective Use of Social Research Studies for Practice” (No. CZ.02.1.01/0.0/0.0/16_025/0007294) and the Czech Science Foundation under reg. No. 18-24977S.Objectives: Associations between the perceived social and physical environment and self-reported moderate-to-vigorous physical activity (MVPA) and screen time (ST) were examined among adolescents in four European countries. Methods: Representative samples were surveyed with standardised methodologies. Associations between environmental variables and meeting MVPA recommendations and tertiles of ST were tested in gender-specific logistic regression models. Moderation by country and country-specific relationships were also examined. Results: The most consistent findings across countries were found for the significant associations between neighbourhood social environment and MVPA in both boys and girls. Significant associations with the physical environment varied more between countries and by gender. The most consistent negative associations with ST were found for the social environmental variable of having parental rules for spending time outside the home. Conclusions: The present findings provided evidence for the generalisability of the associations between environmental correlates and MVPA across four European countries. The findings show clear differences in correlates for MVPA and ST. Further research is needed to better understand the unique aspects of the social and physical environment which explain each of the two behaviours.PostprintPeer reviewe