Phenotypic and functional analysis of positive selection in the gamma/delta T cell lineage.

Recent evidence suggests that T cells expressing gamma/delta antigen receptors (T cell receptor [TCR]) are subject to positive selection during development. We have shown that T cells expressing a class I major histocompatibility complex (MHC)-specific gamma/delta TCR transgene (tg) are not positively selected in class I MHC-deficient, beta 2-microglobulin (beta 2m) gene knockout mice (tg+ beta 2m-). In this report, we examine phenotypic and functional parameters of gamma/delta positive selection in this transgenic model system. TCR-gamma/delta tg+ thymocytes of mature surface phenotype (heat stable antigen-, CD5hi) were found in beta 2m+ but not in beta 2m- mice. Moreover, subsets of tg+ thymocytes with the phenotype of activated T cells (interleukin [IL]2R+, CD44hi, or Mel-14lo) were also present only in the beta 2m+ mice. Cyclosporine A, which blocks positive selection of TCR-alpha/beta T cells, also inhibited gamma/delta tg+ T cell development. These results support the idea that positive selection of TCR-gamma/delta requires active TCR-mediated signal transduction. Whereas tg+ beta 2m+ thymocytes produced IL-2 and proliferated when stimulated by alloantigen, TCR engagement of tg+ beta 2m- thymocytes by antigen induced IL-2R expression but was uncoupled from the signal transduction pathway leading to IL-2 production and autocrine proliferation. Overall, these results demonstrate significant parallels between gamma/delta and alpha/beta lineage development, and suggest a general role for TCR signaling in thymic maturation

Mothers' food choices and consumption of ultra-processed foods in the Brazilian Amazon: A grounded theory study

In recent decades, an increase in consumption of ultra-processed foods (UPF), a type of product frequently associated with diet-related obesity, chronic diseases, decrease of eating traditions and loss of culinary diversity, has been observed in middle-income countries. However, there is lack of information on factors related to choosing UPF. In this study, we aimed to understand the factors promoting UPF choices and consumption among mothers living in an urban context in the Brazilian Amazon, and to present a conceptual model grounded on their experiences that illustrates the dynamics between the observed factors. For this qualitative study, we used a constructive grounded theory approach, with a theoretical sampling of 40 women, to choose mothers with high and low consumption of ultra-processed foods. Data production and the first steps of analysis were performed concomitantly, followed by four steps of coding focused on creating conceptual categories and explaining the interactions between them. Our findings highlighted the importance of context in promoting UPF choice and consumption, particularly the “food environment”, physical and virtual, and the “sociocultural environment”. These contextual aspects interacted with the two main personal aspects influencing participants' UPF consumption, one concerning practices, “cooking behaviors”, and the other concerning preferences, “food tastes”. Factors such as economic and time constraints were also important and competed to shape eating practices through interactions with participants’ health valorization. Findings are discussed in relation to food choice theories, social roles and the food environment. Implications for public health initiatives include the importance of considering environmental changes, sociocultural and economic influences, the reliance on UPF, and the role of women in the home, when promoting healthy diets

Body Composition Indices and Single and Clustered Cardiovascular Disease Risk Factors in Adolescents: Providing Clinical-Based Cut-Points

ArticleThe aims of the present study in adolescents were 1) to examine how various body composition-screening tests relate to single and clustered cardiovascular disease (CVD) risk factors, 2) to examine how lean mass and body fatness (independently of each other) relate to clustered CVD risk factors and, 3) to calculate specific thresholds for body composition indices associated with an unhealthier clustered CVD risk. We measured 1089 European adolescents (46.7% boys, 12.5-17.49yr) in 2006-2007. CVD risk factors included: systolic blood pressure, maximum oxygen uptake, homeostasis model assessment, C-reactive protein (n=748), total cholesterol/high density lipoprotein cholesterol and triglycerides. Body composition indices included: height, body mass index (BMI), lean mass, the sum of four skinfolds, central/peripheral skinfolds, waist circumference (WC), waist-to-height ratio (WHtR) and waist-to-hip ratio (WHR). Most body composition indices are associated with single CVD risk factors. The sum of four skinfolds, WHtR, BMI, WC and lean mass are strong and positively associated with clustered CVD risk. Interestingly, lean mass is positively associated with clustered CVD risk independently of body fatness in girls. Moderate and highly accurate thresholds for the sum of four skinfolds, WHtR, BMI, WC and lean mass are associated with an unhealthier clustered CVD risk (all AUC > 0.773). In conclusion, our results support an association between most of the assessed body composition indices and single and clustered CVD risk factors. In addition, lean mass (independent of body fatness) is positively associated with clustered CVD risk in girls, which is a novel finding that helps to understand why an index such as BMI is a good index of CVD risk but a bad index of adiposity. Moderate to highly accurate thresholds for body composition indices associated with a healthier clustered CVD risk were found. Further studies with a longitudinal design are needed to confirm these findings

Life-History Evolution on Tropidurinae Lizards: Influence of Lineage, Body Size and Climate

The study of life history variation is central to the evolutionary theory. In many ectothermic lineages, including lizards, life history traits are plastic and relate to several sources of variation including body size, which is both a factor and a life history trait likely to modulate reproductive parameters. Larger species within a lineage, for example tend to be more fecund and have larger clutch size, but clutch size may also be influenced by climate, independently of body size. Thus, the study of climatic effects on lizard fecundity is mandatory on the current scenario of global climatic change. We asked how body and clutch size have responded to climate through time in a group of tropical lizards, the Tropidurinae, and how these two variables relate to each other. We used both traditional and phylogenetic comparative methods. Body and clutch size are variable within Tropidurinae, and both traits are influenced by phylogenetic position. Across the lineage, species which evolved larger size produce more eggs and neither trait is influenced by temperature components. A climatic component of precipitation, however, relates to larger female body size, and therefore seems to exert an indirect relationship on clutch size. This effect of precipitation on body size is likely a correlate of primary production. A decrease in fecundity is expected for Tropidurinae species on continental landmasses, which are predicted to undergo a decrease in summer rainfall

HIV-Associated TB in An Giang Province, Vietnam, 2001–2004: Epidemiology and TB Treatment Outcomes

BACKGROUND: Mortality is high in HIV-infected TB patients, but few studies from Southeast Asia have documented the benefits of interventions, such as co-trimoxazole (CTX), in reducing mortality during TB treatment. To help guide policy in Vietnam, we studied the epidemiology of HIV-associated TB in one province and examined factors associated with outcomes, including the impact of CTX use. METHODOLOGY/PRINCIPAL FINDINGS: We retrospectively abstracted data for all HIV-infected persons diagnosed with TB from 2001-2004 in An Giang, a province in southern Vietnam in which TB patients receive HIV counseling and testing. We used standard WHO definitions to classify TB treatment outcomes. We conducted multivariate analysis to identify risk factors for the composite outcome of death, default, or treatment failure during TB treatment. From 2001-2004, 637 HIV-infected TB patients were diagnosed in An Giang. Of these, 501 (79%) were male, 321 (50%) were aged 25-34 years, and the most common self-reported HIV risk factor was sex with a commercial sex worker in 221 (35%). TB was classified as smear-positive in 531 (83%). During TB treatment, 167 (26%) patients died, 9 (1%) defaulted, and 6 (1%) failed treatment. Of 454 patients who took CTX, 116 (26%) had an unsuccessful outcome compared with 33 (70%) of 47 patients who did not take CTX (relative risk, 0.4; 95% confidence interval [CI], 0.3-0.5). Adjusting for male sex, rural residence, TB smear status and disease location, and the occurrence of adverse events during TB treatment in multivariate analysis, the benefit of CTX persisted (adjusted odds ratio for unsuccessful outcome 0.1; CI, 0.1-0.3). CONCLUSIONS/SIGNIFICANCE: In An Giang, Vietnam, HIV-associated TB was associated with poor TB treatment outcomes. Outcomes were significantly better in those taking CTX. This finding suggests that Vietnam should consider applying WHO recommendations to prescribe CTX to all HIV-infected TB patients

A Novel Bocavirus Associated with Acute Gastroenteritis in Australian Children

Acute gastroenteritis (AGE) is a common illness affecting all age groups worldwide, causing an estimated three million deaths annually. Viruses such as rotavirus, adenovirus, and caliciviruses are a major cause of AGE, but in many patients a causal agent cannot be found despite extensive diagnostic testing. Proposing that novel viruses are the reason for this diagnostic gap, we used molecular screening to investigate a cluster of undiagnosed cases that were part of a larger case control study into the etiology of pediatric AGE. Degenerate oligonucleotide primed (DOP) PCR was used to non-specifically amplify viral DNA from fecal specimens. The amplified DNA was then cloned and sequenced for analysis. A novel virus was detected. Elucidation and analysis of the genome indicates it is a member of the Bocavirus genus of the Parvovirinae, 23% variant at the nucleotide level from its closest formally recognized relative, the Human Bocavirus (HBoV), and similar to the very recently proposed second species of Bocavirus (HBoV2). Fecal samples collected from case control pairs during 2001 for the AGE study were tested with a bocavirus-specific PCR, and HBoV2 (sequence confirmed) was detected in 32 of 186 cases with AGE (prevalence 17.2%) compared with only 15 controls (8.1%). In this same group of children, HBoV2 prevalence was exceeded only by rotavirus (39.2%) and astrovirus (21.5%) and was more prevalent than norovirus genogroup 2 (13.4%) and adenovirus (4.8%). In a univariate analysis of the matched pairs (McNemar's Test), the odds ratio for the association of AGE with HBoV2 infection was 2.6 (95% confidence interval 1.2–5.7); P = 0.007. During the course of this screening, a second novel bocavirus was detected which we have designated HBoV species 3 (HBoV3). The prevalence of HBoV3 was low (2.7%), and it was not associated with AGE. HBoV2 and HBoV3 are newly discovered bocaviruses, of which HBoV2 is the thirdmost-prevalent virus, after rotavirus and astrovirus, associated with pediatric AGE in this study

Perceived need for mental health care among non-western labour migrants

Background There is a supposed higher prevalence of common mental disorders among many migrant groups. At the same time, problems are reported regarding underutilisation of mental health services by migrants. Since perceived need for care is a powerful predictor of actual care utilisation, we aimed to study the hypothesis that, given the same level of mental morbidity, non-Western migrants would perceive less need for mental health care than ethnic Dutch residents. Additionally, we studied the extent to which needs are met in both groups, as well as several possible barriers to care. Methods A cross-sectional study with data from the 2004/2005 Amsterdam Health Monitor. Data were complete from 626 ethnic Dutch and non-Western (Turkish and Moroccan) labour migrants. Respondents participated in a structured interview in their own language, which included the perceived need for care questionnaire (PNCQ) and the composite international diagnostic interview (CIDI) version 2.1 for anxiety and depressive disorders. Results Perceived need was much higher among Turkish migrants. Among Moroccans the perceived need was comparable to ethnic Dutch. Turkish migrants also reported that needs were met less often than ethnic Dutch. Differences were explained by a higher prevalence of common mental disorders and higher symptom levels among Turkish. When differences in mental morbidity were taken into account, Moroccans perceived less need for information, drugs, referral to specialised mental health care, or for counselling. The most important barrier to care in all ethnic groups was the preference to solve the problem on one’s own. Conclusion In case of similar mental morbidity, perceived need for care was lower than among ethnic Dutch. The results did not support the hypothesis that in case of similar mental distress, needs of migrants were less often met than needs of ethnic Dutch

Was Dinosaurian Physiology Inherited by Birds? Reconciling Slow Growth in Archaeopteryx

Archaeopteryx is the oldest and most primitive known bird (Avialae). It is believed that the growth and energetic physiology of basalmost birds such as Archaeopteryx were inherited in their entirety from non-avialan dinosaurs. This hypothesis predicts that the long bones in these birds formed using rapidly growing, well-vascularized woven tissue typical of non-avialan dinosaurs. We report that Archaeopteryx long bones are composed of nearly avascular parallel-fibered bone. This is among the slowest growing osseous tissues and is common in ectothermic reptiles. These findings dispute the hypothesis that non-avialan dinosaur growth and physiology were inherited in totality by the first birds. Examining these findings in a phylogenetic context required intensive sampling of outgroup dinosaurs and basalmost birds. Our results demonstrate the presence of a scale-dependent maniraptoran histological continuum that Archaeopteryx and other basalmost birds follow. Growth analysis for Archaeopteryx suggests that these animals showed exponential growth rates like non-avialan dinosaurs, three times slower than living precocial birds, but still within the lowermost range for all endothermic vertebrates. The unexpected histology of Archaeopteryx and other basalmost birds is actually consistent with retention of the phylogenetically earlier paravian dinosaur condition when size is considered. The first birds were simply feathered dinosaurs with respect to growth and energetic physiology. The evolution of the novel pattern in modern forms occurred later in the group's history