Recent studies suggest that leptin, the ob gene product absent in ob/ob mice, is a negative regulator of adiposity. We developed an RIA to measure human leptin in plasma or serum. The minimum detectable concentration by the assay is 0.5 microg/L leptin and the limit of linearity is 100 microg/L. Recovery of leptin added to serum was 99-104% over by the linear range of the assay. The RIA agreed reasonably well with rough quantification by Western blot (RIA = 0.90 blot + 3.7 microg/L, Sy/x = 10.9 microg/L). CVs within- and between-run ranged from 3.4% to 8.3% and from 3.6% to 6.2%, respectively. Variation in plasma leptin concentrations in specimens collected on consecutive mornings was large (CVs of 10.9% and 22.5%). After an overnight fast, leptin concentrations were similar to those 1-2 h after 1-2 meals. Plasma leptin concentrations in specimens from 83 lean and obese adults correlated directly with body mass index (BMI; kg/m2): r = 0.72, P <0.001. Correlations were significantly improved by separating results by gender (men r = 0.84, women r = 0.87; p <0.001). The increase in leptin concentrations with increasing BMI was greater in women than in men (slope 2.53 vs 0.97 microg/L per unit BMI, respectively). Leptin concentrations determined in lean subjects (BMI between 18 and 25) were higher in women (7.36 +/- 3.73 microg/L) than in men (3.84 +/- 1.79 microg/L) (P <0.001). Plasma leptin varied little with age and no significant difference was observed between whites and blacks. We conclude that: (a) plasma leptin concentrations are accurately and precisely measured by this new RIA; (b) leptin concentrations vary little due to short-term fasting, age, or race; but (c) plasma leptin concentrations are gender specific.

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English as a Second Language programs serve large foreign-born populations in the US with elevated risks of tuberculosis (TB), yet little is known about TB perceptions in these settings. Using a community-based participatory research approach, we elicited perceptions about TB among immigrant and refugee learners and staff at a diverse adult education center. Community partners were trained in focus groups moderation. Ten focus groups were conducted with 83 learners and staff. Multi-level, team-based qualitative analysis was conducted to develop themes that informed a model of TB perceptions among participants. Multiple challenges with TB control and prevention were identified. There were a variety of mis-perceptions about transmission of TB, and a lack of knowledge about latent TB. Feelings and perceptions related to TB included secrecy, shame, fear, and isolation. Barriers to TB testing include low awareness, lack of knowledge about latent TB, and the practical considerations of transportation, cost, and work schedule conflicts. Barriers to medication use include suspicion of generic medications and perceived side effects. We posit adult education centers with large immigrant and refugee populations as excellent venues for TB prevention, and propose several recommendations for conducting these programs. Content should dispel the most compelling misperceptions about TB transmission while clarifying the difference between active and latent disease. Learners should be educated about TB in the US and that it is curable. Finally, TB programs that include learners and staff in their design and implementation provide greater opportunity for overcoming previously unrecognized barriers.

We tested the hypothesis that hypoxia diminishes the expression and transport of neutral amino acids by system A in full-term human trophoblasts. Cytotrophoblasts from normal human placentas were cultured in standard conditions of 20% O(2) or in 1% and 3% O(2) for 24 h before assay. Neutral amino acid transport for systems A, ASC, and L was assayed at 24 and 72 h by the cluster-tray technique. Hypoxia during the initial 24 h of culture reduced system A transport by 82% in 1% O(2) and by 37% in 3% O(2) (P < 0.01) compared with standard conditions. Hypoxia during the latter 24 h of the 72 h in culture reduced system A transport by 55% in 1% O(2) and by 20% in 3% O(2) (P < 0.05) compared with standard conditions at 72 h. Hypoxia (1% O(2)) also reduced total amino acid transport by 40% in the more differentiated syncytiotrophoblasts present at 72 h. Northern analysis of trophoblasts in standard conditions showed that subtypes of human amino acid transporter A (hATA1 and hATA2) were each expressed in cytotrophoblasts and syncytiotrophoblasts. Hypoxia decreased expression of hATA1 and hATA2 in both trophoblast phenotypes. We conclude that hypoxia downregulates system A transporter expression and activity in cultured human trophoblasts.

Background Despite improvements in mortality rates over the past several decades, cardiovascular (CV) disease remains the leading cause of death for African-Americans (AAs). Innovative approaches through mobile health (mHealth) interventions have the potential to support lifestyle change for CV disease prevention among AAs. We aimed to translate a behavioral theory–informed, evidence-based, face-to-face health education program into an mHealth lifestyle intervention for AAs. We describe the design and development of a culturally relevant, CV health and wellness digital application (app) and pilot testing using a community-based participatory research (CBPR) approach with AA churches. Methods This mixed methods study used a 4-phase iterative development process for intervention design with the AA community. Phase 1 included focus groups with AA community members and church partners (n = 23) to gain insight regarding potential app end user preferences. In Phase 2, the interdisciplinary research team synthesized Phase 1 input for preliminary app design and content development. Phase 3 consisted of a sequential 3-meeting series with church partners (n = 13) for iterative app prototyping (assessment, cultural tailoring, final review). Phase 4, a single group pilot study among AA church congregants (n = 50), assessed app acceptability, usability, and satisfaction. Results Phase 1 focus groups indicated general and health-related apps preferences: multifunctional, high-quality graphics/visuals, evidence-based, yet simple health information and social networking capability. Phase 2 integrated these preferences into the preliminary app prototype. Phase 3 feedback was used to refine the app prototype for pilot testing. Phase 4 pilot testing indicated high app acceptability, usability, and satisfaction. Conclusions This study illustrates integration of formative and CBPR approaches to design a culturally relevant, mHealth lifestyle intervention to address CV health disparities among AAs. Given the positive app perceptions, our study supports the use of an iterative development process by others interested in implementing an mHealth lifestyle intervention for racial/ethnic minority communities. Trial registration Clinicaltrials.gov NCT03084822 .

The present research used multiple methods to examine the hypothesis that perceived true self-knowledge and decision satisfaction are inextricably linked together by a widely held "true-self-as-guide" lay theory of decision making. Consistent with this proposition, Study 1 found that participants rated using the true self as a guide as more important for achieving personal satisfaction than a variety of other potential decision-making strategies. After establishing the prevalence of this lay theory, the remaining studies then focused on examining the proposed consequent relationship between perceived true self-knowledge and decision satisfaction. Consistent with hypotheses, 2 cross-sectional correlational studies (Studies 2 and 3) found a positive relationship between perceived true self-knowledge and decision satisfaction for different types of major decisions. Study 4 used daily diary methods to demonstrate that fluctuations in perceived true self-knowledge reliably covary with fluctuations in decision satisfaction. Finally, 2 studies directly examined the causal direction of this relationship through experimental manipulation and revealed that the relationship is truly bidirectional. More specifically, Study 5 showed that manipulating perceived knowledge of the true self (but not other self-concepts) directly affects decision satisfaction. Study 6 showed that this effect also works in reverse by manipulating feelings of decision satisfaction, which directly affected perceived knowledge of the true self (but not other self-concepts). Taken together, these studies suggest that people believe the true self should be used as a guide when making major life decisions and that this belief has observable consequences for the self and decision making.

Ion-exchange chromatography with ninhydrin detection remains the gold standard for detecting inborn errors of amino acid catabolism and transport. Disadvantages of such analysis include long chromatography times and interference from other ninhydrin-positive compounds. The aim of this project was to develop a more rapid and specific technique using liquid chromatography/tandem mass spectrometry (LC/MS/MS). Optimal fragmentation patterns for 32 amino acids were determined on a triple quadrupole mass spectrometer following butylation. Chromatographic characteristics of each of the amino acids were determined using C8 reversed-phase chromatography with 20% acetonitrile/0.1% formic acid as isocratic mobile phase. Quantitation using eleven deuterated internal standards was compared to cation exchange and ninhydrin detection on a Beckman 7300 system. Following methanol extraction and butylation, determination of 32 amino acids required 20 min. The dynamic range of each amino acid was generally 1-1000 micromol/L. Imprecision ranged from 7 to 23% (CV) over 6 months and recovery ranged from 88-125%. Deming regression with the Beckman 7300 yielded slopes from 0.4-1.2, intercepts from -21 to 65 micromol/L, correlation coefficients from 0.84-0.99 and Syx from 2-125 micromol/L. Isobaric amino acids were separated by chromatography (e.g. leucine, isoleucine) or by unique fragmentation (e.g., alanine, beta-alanine). LC/MS/MS is comparable to traditional LC-ninhydrin detection. Mass spectral detection shortens analysis times and reduces potential for interference in detecting inborn metabolic errors.

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