A proof-of-concept study testing the factor structure of the Stop Signal Task: overlap with substance use and mental health symptoms.

Background: Research utilizing experimental tasks usually does not report estimates of internal reliability of measurement. However, modern measurement theories conceptualize reliability as sample dependent indicating that reliability should be empirically demonstrated in the samples used to make inferences.Objectives: Test whether confirmatory factor analytic (CFA) estimates of reliability can be applied to a commonly used task measuring response inhibition (the Stop Signal Task) to predict substance use (alcohol and cannabis) and mental health symptoms.Methods: Thirty-seven participants between the ages of 18-20 (72% female; 16% Asian, 3% Native American, 11% Black or African American, 59% White; 32% Latino/a/x) were recruited via social media advertisement and attended a laboratory visit. The Stop Signal Reaction Time (SSRT) was calculated as the outcome for three experimental blocks and used as indicators in a CFA.Results: CFA suggests the task yields reliable scores; factor loadings were statistically significant (p < .05) and substantial (standardized loadings ranged from .74 to .94). However, reliability increased across experimental blocks and error was non-trivial (ranging from 50% to 12% of the variance). The inhibition factor predicted higher maximum number of drinks consumed (ß = .37, p < .05), higher frequency of cannabis use (ß = .39, p < .05), and more cannabis use occasions within using days (ß = .40, p < .05), as well as facets of mental health (anxious/depression, attention, and anxiety problems; all p's < .05).Conclusion: Results support the utility of CFA to test for reliability of measurement, with the ability to inhibit dominant responses serving as a transdiagnostic correlate of substance use and mental health problems.

Use of the BACtrack Skyn alcohol biosensor: Practical applications for data collection and analysis.

AIMS: Alcohol biosensors, including the BACtrack Skyn, provide an objective and passive method of continuously assessing alcohol consumption in the natural environment. Despite the many strengths of the Skyn, six key challenges in the collection and processing of data include (1) identifying consumed alcohol; (2) identifying environmental alcohol; (3) identifying and determining the source of missing or invalid data; (4) achieving high participant adherence; (5) integrating Skyn and self-report data; and (6) implications for statistical inference. In this report we outline these challenges, provide recommendations to address them and identify future needs. DESIGN AND SETTINGS: Procedures from several laboratory and field-based pilot studies are presented to demonstrate practical recommendations for Skyn use. Data from a pilot study including a 7-day ecological momentary assessment period are also presented to evaluate effects of environmental alcohol on BACtrack Skyn readings. CONCLUSIONS: To address challenges in the collection and processing of data from the BACtrack Skyn alcohol biosensor, researchers should identify goals in advance of data collection to anticipate the processing necessary to interpret Skyn data. The Transdermal Alcohol Sensor Data Macro (TASMAC) version 2.0 software can help to process data rapidly; identify drinking events, missing data and environmental alcohol; and integrate the sensor with self-report data. Thorough participant orientation and regular contact in field studies can reduce missing data and enhance adherence. Many recommended methods for Skyn use are applicable to other alcohol sensors and wearable devices.

Affective and physiological response to a novel parent-adolescent conflict stressor.

Few laboratory paradigms exist that expose adolescents to conflict that might commonly be experienced in parent-adolescent relationships. Given the continued importance of parent-adolescent relationships on adolescent development, as well as the changing expectations in these relationships, we examined the effect of a novel parent-adolescent conflict paradigm on physiological and affective response in a sample of 52 adolescents. The parent-adolescent conflict stressor (PACS) involved adolescent participants (50% girls; M = 14.75, SD = 0.88) watching a 12-minute scripted video that asked youth to imagine that they were the teenager in the video, which consisted of parent and adolescent actors having discussions about conflict in their relationship and solving this conflict in either a positive, typical, or hostile manner. Cortisol, alpha amylase, and self-report of negative and positive affect were collected at baseline, following the video, and during a recovery period. Heart rate also was taken continuously while adolescents watched the videos. Hierarchical linear modeling (HLM) analyses indicated significant linear change in alpha amylase and linear and quadratic change in negative affect to the PACS. There also was a significant linear and quadratic change in heart rate during the portion of the video where teens and parents discussed issues of personal responsibility. The PACS marks a preliminary but important first step in developing a parent-adolescent conflict paradigm that can be used across studies to understand the impact of parent-adolescent conflict on affective and physiological markers associated with stress response.

Decreased levels of both Stat1 and Stat3 in T lymphocytes from mice bearing mammary tumors.

BACKGROUND: Lymphocytes from tumor-bearing animals have been shown to lack antitumor function. The objective of this study was to investigate the status of the signal transducers, Stat1 and Stat3, in T lymphocytes of animals bearing D1-DMBA-3 mammary tumors and to elucidate if any alterations in these signal transducers can be explained by the presence of tumor-derived factors and correlated with the lack of antitumor function in these cells. MATERIALS AND METHODS: T Lymphocytes from spleens of normal and tumor-bearing mice were purified and assayed for the presence of Stat1 and Stat3 by Western blot analysis. RESULTS: It was found that levels of both Stat1 and Stat3 were reduced in T lymphocytes of tumor-bearers not only in their active, phosphorylated form but in total protein levels. CONCLUSION: These findings indicate that during mammary tumor progression, alteration of various transcription factors may contribute to the down-regulation of immune function.

Antitumor effects of Mucin 1/sec involves the modulation of urokinase-type plasminogen activator and signal transducer and activator of transcription 1 expression in tumor cells.

Expression of the transmembrane isoform of Mucin 1 (MUC1/TM) in an aggressive murine mammary tumor line, DA-3, does not alter tumor development and metastasis, leading to death of the host. However, tumor cells expressing a secreted isoform of MUC1 (MUC1/sec) fail to develop tumors in immunocompetent mice. The rejection of MUC1/sec-expressing tumor cells is immunologically mediated, as, initially, innate cells and, ultimately, T cells are required. After gene array analysis, and confirmation at the protein level, it was discovered that MUC1/sec-expressing tumor cells (DA-3/sec) have a significant reduction in expression of urokinase-type plasminogen activator (uPA) relative to the parental tumor line and tumor cells expressing MUC1/TM. The serine protease uPA has been found to be involved in growth-promoting signaling, angiogenesis, and induction of matrix remodeling leading to metastasis. Although the tumor-promoting Stat3 transcription factor was unaltered in these tumor cells, the tumor-suppressive and IFN-responsive signal transducer and activator of transcription 1 (Stat1) is dramatically up-regulated in DA-3/sec cells. In addition, treatment of various murine and human cell lines with conditioned medium containing MUC1/sec results in up-regulation of Stat1. DA-3/sec tumor cells are also sensitized to the antiproliferative effects of IFN-gamma. Furthermore, transfection of the Stat1 gene into DA-3 tumor cells leads to a down-regulation of uPA and delays tumor progression. Thus, Stat1 up-regulation in DA-3/sec cells seems to play a significant role in the mechanism(s) by which rejection of tumor cells expressing MUC1/sec may be occurring.