Overlooked Threats to Respondent Driven Sampling Estimators: Peer Recruitment Reality, Degree Measures, and Random Selection Assumption.

Intensive sociometric network data were collected from a typical respondent driven sample (RDS) of 528 people who inject drugs residing in Hartford, Connecticut in 2012-2013. This rich dataset enabled us to analyze a large number of unobserved network nodes and ties for the purpose of assessing common assumptions underlying RDS estimators. Results show that several assumptions central to RDS estimators, such as random selection, enrollment probability proportional to degree, and recruitment occurring over recruiter's network ties, were violated. These problems stem from an overly simplistic conceptualization of peer recruitment processes and dynamics. We found nearly half of participants were recruited via coupon redistribution on the street. Non-uniform patterns occurred in multiple recruitment stages related to both recruiter behavior (choosing and reaching alters, passing coupons, etc.) and recruit behavior (accepting/rejecting coupons, failing to enter study, passing coupons to others). Some factors associated with these patterns were also associated with HIV risk.

Using Ecological Momentary Assessment to Identify Common Smoking Situations Among Korean American Emerging Adults.

The present study provides detailed contextual information about smoking habits among young Korean American smokers with the goal of characterizing situations where they are most at risk for smoking. Relevant situational factors included location, social context, concurrent activities, time of day, affective states, and food and beverage consumption. Using ecological momentary assessment (EMA) over 7 days, participants (N = 78) were instructed to respond to smoking prompts (n = 2614) and non-smoking prompts (n = 2136) randomly scheduled throughout the day. At each prompt, participants completed a short survey about immediate contextual factors. We used multilevel models to evaluate the association between contextual factors and smoking and further explored the distribution of smoking locations and concurrent activities across each social context and reason for smoking. Compared to non-smoking events, smoking events were associated with being outside, the presence of Korean friends, socializing, consuming alcohol, and experiencing more stress relative to one's average stress level (all ps < .01). Further analyses involving only smoking events showed that when participants smoked alone, they were most commonly at home (50 %) and most often studying/working (28 %). When smoking with Korean friends, participants were most often outside (38 %) and socializing (54 %). When smoking to reduce craving, participants were most often at home (39 %) and studying/working (25 %). To our knowledge, this is the first study to provide detailed descriptions of real-time smoking contexts among young Korean American smokers. Information with this level of granularity is needed to develop effective just-in-time adaptive interventions (JITAIs) for smoking cessation.

Toll-like receptor-based immuno-analysis of pathogenic microorganisms.

In this study, a novel mammalian cell receptor-based immuno-analytical method was developed for the detection of food-poisoning microorganisms by employing toll-like receptors (TLRs) as sensing elements. Upon infection with bacterium, the host cells respond by expressing TLRs, particularly TLR1, TLR2, and TLR4, on the outer membrane surfaces. To demonstrate the potential of using this method for detection of foodborne bacteria, we initially selected two model sensing systems, expression of TLR1 on a cell line, A549, for Escherichia coli and TLR2 on a cell line, RAW264.7, for Shigella sonnei (S. sonnei). Each TLR was detected using antibodies specific to the respective marker. We also found that the addition of immunoassay for the pathogen captured by the TLRs on the mammalian cells significantly enhanced the detection capability. A dual-analytical system for S. sonnei was constructed and successfully detected an extremely low number (about 3.2 CFU per well) of the pathogenic bacterium 5.1 h after infection. This detection time was 2.5 h earlier than the time required for detection using the conventional immunoassay. To endow the specificity of detection, the target bacterium was immuno-magnetically concentrated by a factor of 50 prior to infection. This further shortened the response to approximately 3.4 h, which was less than half of the time needed when the conventional method was used. Such enhanced performance could basically result from synergistic effects of bacterial dose increase and subsequent autocrine signaling on TLRs' up-regulation upon infection with live bacterium. This TLR-based immuno-sensing approach may also be expanded to monitor infection of the body, provided scanning of the signal is feasible.

Use of Social Network Analysis to Identify Popular Opinion Leaders for a Youth-Led Sexual Violence Prevention Initiative.

In the current article, we describe an innovative sexual violence (SV) prevention initiative that used social network analysis to identify youth and adult popular opinion leaders who were subsequently trained in best practices in SV prevention (e.g., bystander intervention) at a kickoff event (i.e., camp) of the initiative. We provide information on recruitment strategies, participation rates and how those rates varied by some demographic factors, reasons for nonattendance, the initial impact of the camp, and lessons learned. Despite challenges with youth and adult engagement, this innovative approach has the potential to transform the way we approach SV prevention among youth.

Up-regulation of bradykinin B2 receptor by Pseudomonas aeruginosa via the NF-κB pathway.

As the first line of host defense, inflammatory responses in response to bacterial infection are initiated by the production of a range of mediators. Infection of Pseudomonas aeruginosa has been shown to stimulate the production of bradykinin (BK), which is known as a universal mediator for the induction of inflammatory reaction via the predominant interaction with the bradykinin B2 receptor (B2R). Thus, the interaction between BK and B2R represents an important host innate response against invading P. aeruginosa. However, the contribution of P. aeruginosa to the up-regulation of B2R expression remains unclear. Here, we report that P. aeruginosa is potent in inducing the expression of B2R at the mRNA and protein levels in a dose- and time-dependent manner. Components produced and secreted from P. aeruginosa could play an essential role in inducing B2R expression, and the secreted components are not under the control of Type III secretion system or quorum sensing. B2R expression in response to P. aeruginosa is mediated by the induction of cellular signaling that leads to the activation of transcription factor NF-κB. Thus, this study demonstrates that P. aeruginosa is able to up-regulate the expression of B2R during infection via the NF-κB signaling pathway.

Autoinduction of a genetic locus encoding putative acyltransferase in Corynebacterium glutamicum.

A genetic locus, encoding putative acyltransferase, was induced by autoinducers in Corynebacterium glutamicum. The autoinducers were maximally produced by the bacterium after 24 h culture. Those molecules are resistant to proteinase K treatment (300 µg ml(-1)) for 30 min at 37°C or at 121°C for 15 min, and remained stable after extensive storage at 4°C. Autoinducers in the cell-free culture fluids from Corynebacterium ammoniagenes and Pseudomonas aeruginosa also induced the expression of acyltransferase in C. glutamicum, suggesting possible cross-recognition of the autoinducers by C. glutamicum. C. glutamicum thus possesses an autoinduction system which secretes autoinducers during growth, triggering the expression of downstream genes, exemplified by the putative acyltransferase gene.

Pik3ca is required for mouse uterine gland development and pregnancy.

The PI3K/AKT signaling pathway plays a critical role in the maintenance of equilibrium between cell survival and apoptosis. The Pik3ca gene is mutated in a range of human cancers. It has been found to be oncogenic, and mutations lead to constitutive activation of the PI3K/AKT pathway. The expression patterns of PIK3CA proteins in the uterus of mice during early pregnancy indicate that it may play a role in the regulation of glandular epithelial cells, which is required to support uterine receptivity. To further investigate the role of Pik3ca in uterine function, Pik3ca was conditionally ablated only in the PGR-positive cells (Pgrcre/+Pik3caf/f; Pik3cad/d). A defect of uterine gland development and decidualization led to subfertility observed in Pik3cad/d mice. Pik3cad/d mice showed significantly decreased uterine weight compared to Pik3caf/f mice. Interestingly, a significant decrease of gland numbers were detected in Pik3cad/d mice compared to control mice. In addition, we found a decrease of Foxa2 expression, which is a known uterine gland marker in Pik3cad/d mice. Furthermore, the excessive proliferation of endometrial epithelial cells was observed in Pik3cad/d mice. Our studies suggest that Pik3ca has a critical role in uterine gland development and female fertility.

Determination of Optimized Growth Medium and Cryoprotective Additives to Enhance the Growth and Survival of Lactobacillus salivarius.

The beneficial effects of lactic acid bacteria (LAB) have been intensively investigated in recent decades with special focus on modulation of the host intestinal microbiota. Numerous discoveries of effective probiotics are driven by a significantly increasing demand for dietary supplements. Consequently, technological advances in the large-scale production and lyophilization are needed by probiotic-related industries for producing probiotic LAB for commercial use. Our study had a dual objective, to determine the optimum growth medium composition and to investigate appropriate cryoprotective additives (CPAs) for Lactobacillus salivarius, and compare its responses with other Lactobacillus species. The one-factor-at-a-time method and central composite design were applied to determine the optimal medium composition for L. salivarius cultivation. The following composition of the medium was established (per liter): 21.64 g maltose, 85 g yeast extract, 1.21 ml Tween 80, 6 g sodium acetate, 0.2 g MgSO4∙7H2O, 0.02 g MnSO4∙H2O, 1 g K2HPO4, 1.5 g KH2PO4, 0.01 g FeSO4∙7H2O, and 1 g sodium citrate. A cryoprotective additive combination comprising 10% (w/v) skim milk and 10% (w/v) sucrose supplemented with 2.5% (w/v) sodium glutamate was selected for L. salivarius, and its effectiveness was confirmed using culture-independent methods in the freeze-dried cells of the Lactobacillus strains. In conclusion, the optimized medium enhanced the species-specific cultivation of L. salivarius. On the other hand, the cryoprotective effects of the selected CPA mixture may also be dependent on the bacterial strain. This study highlights the necessity for precise and advanced processing techniques for large-scale production of probiotics in the food and feed industries.

Associations among dispositional mindfulness, self-compassion, and executive function proficiency in early adolescents.

The study objective was to examine the effects of two conceptually related constructs, self-compassion and dispositional mindfulness, on executive function (EF) proficiency among early adolescents. Executive function refers to a set of psychological processes governing emotional regulation, organization, and planning. While the benefits of positive psychology appear evident for mental health and wellness, little is known about the etiological relationship between dispositional mindfulness and self-compassion in their associations with EF. Two hundred and ten early adolescents attending middle school (age M=12.5 years; SD=0.5; 21% Hispanic, 18% Mixed/bi-racial, 47% White, and 9% Other/Missing; 37.1% on free lunch program) self-reported levels of dispositional mindfulness (Mindful Attention Awareness Scale; MAAS), self-compassion (Self-Compassion Scale; SCS; self-judgment and self-kindness domains), and EF proficiency (Behavior Rating Inventory of Executive Function; BRIEF-SR). A sequential linear regression stepwise approach was taken entering the independent variables as separate models in the following order: self-kindness, self-judgement, and dispositional mindfulness. All models controlled for participant age and sex. SCS self-kindness was not associated with EF proficiency, but SCS self-judgment (reverse-coded) contributed to the variance in EF (ß=0.40, p<.001). When adding MAAS to the model, MAAS scores were significantly associated with EF (ß=0.64, p<.001) and accounted for the initial variance explained by SCS. When considering the influence of positive psychology constructs on EF proficiency in adolescents, the measure of dispositional mindfulness appears to outweigh that of specific self-compassion domains, when independent of contemplative training.

Identification of D-amino acid dehydrogenase as an upstream regulator of the autoinduction of a putative acyltransferase in Corynebacterium glutamicum.

Expression of a putative acyltransferase encoded by NCgl- 0350 of Corynebacterium glutamicum is induced by cell-free culture fluids obtained from stationary-phase growth of both C. glutamicum and Pseudomonas aeruginosa, providing evidence for interspecies communication. Here, we further confirmed that such communication occurs by showing that acyltransferase expression is induced by culture fluid obtained from diverse Gram-negative and -positive bacterial strains, including Escherichia coli, Salmonella Typhimurium, Bacillus subtilis, Staphylococcus aureus, Mycobacterium sp. strain JC1, and Mycobacterium smegmatis. A homologous acyltransferase encoded by PA5238 of P. aeruginosa was also induced by fluids obtained from P. aeruginosa as well as other bacterial strains, as observed for NCgl0350 of C. glutamicum. Because C. glutamicum is difficult to study using molecular approaches, the homologous gene PA5238 of P. aeruginosa was used to identify PA5309 as an upstream regulator of expression. A homologous D-amino acid dehydrogenase encoded by NCgl- 2909 of C. glutamicum was cloned based on amino acid similarity to PA5309, and its role in the regulation of NCgl0350 expression was confirmed. Moreover, NCgl2909 played positive roles in growth of C. glutamicum. Thus, we identified a D-amino acid dehydrogenase as an upstream regulator of the autoinduction of a putative acyltransferase in C. glutamicum.

The effects of teacher fidelity of implementation of pathways to health on student outcomes.

Previous research has demonstrated the importance of ensuring that programs are implemented as intended by program developers in order to achieve desired program effects. The current study examined implementation fidelity of Pathways to Health (Pathways), a newly developed obesity prevention program for fourth- through sixth-grade children. We explored the associations between self-reported and observed implementation fidelity scores and whether implementation fidelity differed across the first 2 years of program implementation. Additionally, we examined whether implementation fidelity affected program outcomes and whether teacher beliefs were associated with implementation fidelity. The program was better received, and implementation fidelity had more effects on program outcomes in fifth grade than in fourth grade. Findings suggest that implementation in school-based obesity programs may affect junk food intake and intentions to eat healthfully and exercise. School support was associated with implementation fidelity, suggesting that prevention programs may benefit from including a component that boosts school-wide support.

Prospective associations between bilingualism and executive function in Latino children: sustained effects while controlling for biculturalism.

The study purpose was to test 1-year prospective associations between English-Spanish bilingualism and executive function in 5th to 6th grade students while controlling for biculturalism. Participants included 182 US Latino students (50 % female). Self-report surveys assessed biculturalism, bilingualism, and executive function (i.e., working memory, organizational skills, inhibitory control, and emotional control, as well as a summary executive function score). General linear model regressions demonstrated that bilingualism significantly predicted the summary executive function score as well as working memory such that bilingual proficiency was positively related to executive function. Results are the first to demonstrate (a) prospective associations between bilingualism to executive function while controlling for the potential third variable of biculturalism, and (b) a principal role for working memory in this relationship. Since executive function is associated with a host of health outcomes, one implication of study findings is that bilingualism may have an indirect protective influence on youth development.

The interaction of social networks and child obesity prevention program effects: the pathways trial.

OBJECTIVE: Social network analysis was used to examine whether peer influence from one's social networks moderates obesity prevention program effects on obesity-related behaviors: healthful and unhealthful. METHODS: Participants included 557 children residing in Southern California. The survey assessed health-promoting behaviors (i.e., physical activity at school, physical activity outside of school, and fruit and vegetable intake), as well as unhealthful behaviors (high-calorie, low-nutrient intake and sedentary activity), and peer exposure calculated from social network nominations as indicators of peer influence. Multilevel models were conducted separately on outcomes predicted by program participation, peer exposure, and program participation by peer exposure. RESULTS: Results indicated that peer exposure was positively associated with one's own healthful and unhealthful behaviors. Program participation effects were moderated by peer influence, but only when unhealthful peer influence was present. Results suggest that peer influence can diminish or amplify prevention programs CONCLUSION: Future interventions should consider peer-led components to promote healthful influence of peers on healthful and unhealthful behaviors, and programs should be mindful that their effects are moderated by social networks.

Pseudomonas aeruginosa-dependent upregulation of TLR2 influences host responses to a secondary Staphylococcus aureus infection.

The clinical impact of polymicrobial infections has received increasing attention from the medical community. However, the potential effects of Pseudomonas aeruginosa infection on the development of host responses against Gram-positive bacteria, such as Staphylococcus aureus, are unknown. Here, P. aeruginosa infection was found to induce the expression of Toll-like receptor 2 (TLR2), which plays a dominant role in sensing pathogen-associated molecular patterns (PAMPs) expressed by Gram-positive bacteria. P. aeruginosa-dependent upregulation of TLR2 was not mediated by flagellin, or by the type III (T3SS) or type VI (T6SS) secretion systems, but was upregulated by lipopolysaccharide (LPS). Upregulation of TLR2 influenced the magnitude of proinflammatory responses to the secondary S. aureus infection, but there was no clear effect on phagocytosis of S. aureus by macrophages. Taken together, the results of this study demonstrate that P. aeruginosa infection results in the upregulation of TLR2 expression, subsequently enhancing innate immune responses against a secondary S. aureus infection.

Pneumolysin-mediated expression of ß-defensin 2 is coordinated by p38 MAP kinase-MKP1 in human airway cells.

Antimicrobial peptides act as important innate immune defense mediators against invading microbes such as Streptococcus pneumoniae. Among a number of antimicrobial peptides, ß-defensin 2 (BD2) has strong antimicrobial activity against S. pneumoniae. However, little is known about the molecular signaling mechanisms leading to the BD2 expression. Here, we report that BD2 is strongly induced by S. pneumoniae in human airway cells including human middle-ear cells. Among diverse pneumococcal virulence factors, pneumolysin is required for inducing BD2 whose expression is under the control of p38 mitogen-activated protein kinase (MAPK). Pneumolysin also selectively regulates the expression of MAPK phosphatase 1 (MKP1), which inhibits the p38 signaling pathway, thereby leading to upregulation of BD2 to mount an effective defense against S. pneumoniae infection. These results provide novel insights into the molecular mechanisms underlying the coordinative regulation of BD2 expression via p38-MKP1 in the pathogenesis of airway infectious diseases.

Up-regulation of human bradykinin B1 receptor by secreted components of Pseudomonas aeruginosa via a NF-κB pathway in epithelial cells.

Pulmonary epithelial cells produce neutrophil chemotactic activity in response to pathogenic bacterial infections, resulting in neutrophil migration to infection sites. Elicited neutrophils in the inflamed tissues were found to be dependent on bradykinin B1 receptor (B1R), which shows high affinity for the active metabolites derived from bradykinin. Thus, the up-regulation of bradykinin and B1R expression represents an important host defense response against invading microbes such as Pseudomonas aeruginosa. However, the effect of P. aeruginosa on the expression of B1R remains unclear, while P. aeruginosa infection is known to stimulate the production of bradykinin. Here, we report that human B1R (hB1R) transcription is up-regulated in host cells co-cultured with P. aeruginosa. Components secreted from P. aeruginosa play a major role in the up-regulation, and the secretion of the components is not controlled by either type III secretion system or quorum sensing. Moreover, the B1R induction is mediated by a NF-κB signaling pathway in human lung epithelial cells. Taken together, this study demonstrates that P. aeruginosa is capable of up-regulating hB1R expression via the NF-κB signaling pathway.

Measuring the meanings of eating in minority youth.

The aim of this study is to present the development of the Meanings of Eating Index (MEI) in a diverse sample of children. Exploratory factor analysis was performed on MEI items. Factors with eigenvalues above 1.0 were retained. Items that loaded on multiple factors or with item-total correlations below 0.50 were discarded. A 24-item, 5-factor scale comprised the final MEI. Personal Negative Emotions and Disturbed Eating were positively associated with frequency of high calorie snack food intake (r=0.21, p<0.05; r=0.33, p<0.01), and Personal Well Being was positively associated with eating vegetables more frequently (r=0.20; p<0.05). Eating on Behalf of Others was negatively associated with frequency of vegetable intake (r=-.20; p<0.05). Pleasure Eating was not associated with dietary intake. The MEI shows promise as a tool for understanding the affective determinants of dietary intake in minority youth.

MKP1 regulates the induction of MCP1 by Streptococcus pneumoniae pneumolysin in human epithelial cells.

Epithelial cells act as the first line of host defense against microbes by producing a range of different molecules for clearance. Chemokines facilitate the clearance of invaders through the recruitment of leukocytes. Thus, upregulation of chemokine expression represents an important innate host defense response against invading microbes such as Streptococcus pneumoniae. In this study, we report that the expression of Monocyte Chemotactic Protein 1 (MCP1) was highly induced in response to S. pneumoniae in vitro and in vivo. Among numerous virulence factors, pneumococcal pneumolysin was found to be the major factor responsible for this induction. Furthermore, MCP1 induction was mediated by the p38 mitogen-activated protein kinase (MAPK) whose activation was controlled by MAPK phosphatase 1 (MKP1). Therefore, this study reveals novel roles of pneumolysin in mediating MKP1 expression for the regulation of MCP1 expression in human epithelial cells.

Role of pneumococcal pneumolysin in the induction of an inflammatory response in human epithelial cells.

Epithelial cells act as the first line of host defense against microorganisms by producing a range of molecules for clearance. Proinflammatory cytokines facilitate the clearance of invaders by the recruitment and activation of leukocytes. Upregulation of cytokine expression thus represents an important host innate defense response against invading microorganisms such as Streptococcus pneumoniae. Histological analysis of the airway revealed less leukocyte infiltration during the early stage of pneumococcal infection, when compared with nontypable Haemophilus influenzae (NTHi) infection. Here, we report that S. pneumoniae is less potent in inducing proinflammatory cytokine expression compared with NTHi. Among numerous virulence factors, pneumococcal pneumolysin was found to be the major factor responsible for the induction of inflammation. Interestingly, pneumolysin induces cytokine expression to a lesser extent at the early stage of infection, but becomes more potent in inducing inflammation at the late stage. Thus, this study reveals that pneumolysin induces the proinflammatory cytokine expression in a time-dependent manner.

MKP1 regulates the induction of inflammatory response by pneumococcal pneumolysin in human epithelial cells.

The expression of proinflammatory cytokines represents an important host innate response during infections. The reduction of cytokine expression thus mediates impaired host defenses. We previously reported that pneumococcal pneumolysin is less potent in inducing inflammatory responses in human epithelial cells at the early stage of treatment. How this might occur in response to pneumolysin is still not clearly understood. Here, we show the expression of tumor necrosis factor-α (TNF-α) was reduced by MAPK phosphatase 1 (MKP1), expression of which was significantly increased in response to pneumolysin at the early stage of treatment. TNF-α expression was mediated in a time-dependent manner by p38 mitogen-activated protein kinase, activation of which is under the control of MKP1. Thus, this study reveals novel roles of pneumolysin in mediating MKP1 expression for the regulation of proinflammatory cytokine expression in a time-dependent manner.