Motives matter: White instructors' external race-based motives undermine trust and belonging for Black college students.

OBJECTIVE: Trust is fundamental to successful educational relationships. Yet, numerous barriers inhibit the development of trust between students of color (SOC) and White instructors. The current research examined a metacognitive obstacle to the development of cross-race classroom trust: Primarily External Race Motives (PERM). PERM was defined as the experience that instructors were more concerned with avoiding the appearance of prejudice than having self-directed egalitarian motives. METHOD: Using within-subjects vignettes (n = 313; 74.8% female), between-subjects cross-sectional designs (n = 386; 70.5% female), and longitudinal methods (n = 135; 45.2% female), the current work tested the primary hypothesis that PERM would undermine instructor trust and classroom belonging. Hypotheses were tested with Black adults (Study 1) and college students (Studies 2 and 3). RESULTS AND CONCLUSIONS: Whether with hypothetical, past, or present White educators, feeling that instructors have primarily external race-based motives undermined instructor trust and classroom belonging. In all studies, the relationship between PERM and classroom belonging was mediated by instructor (mis)trust. The results provide evidence that motives viewed to be primarily external undermine instructional relationships for SOC. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Impact of Binge Alcohol Intoxication on the Humoral Immune Response during Burkholderia spp. Infections.

Burkholderia pseudomallei, the causative agent of melioidosis can occur in healthy humans, yet binge alcohol use is progressively being recognized as a major risk factor. Currently, no experimental studies have investigated the effects of binge alcohol on the adaptive immune system during an active infection. In this study, we used B. thailandensis and B. vietnamiensis, to investigate the impact of a single binge alcohol episode on the humoral response during infection. Eight-week-old female C57BL/6 mice were administered alcohol comparable to human binge drinking (4.4 g/kg) or PBS intraperitoneally 30 min before intranasal infection. Mice infected with B. thailandensis had a 100% survival rate, while those infected with B. vietnamiensis had a 33% survivability rate when a binge alcohol dose was administered. B. thailandensis was detected in blood of mice administered alcohol at only 7 days post infection (PI), while those infected with B. vietnamiensis and receiving alcohol were found throughout the 28-day infection as well as in tissues at day 28 PI. Binge alcohol elevated IgM and delayed IgG specific to the whole cell lysate (WCL) of B. vietnamiensis but not B. thailandensis infections. Differences in immunogenicity of B. pseudomallei near-neighbors provide a framework for novel insights into the effects of binge alcohol's suppression of the humoral immune response that can cause opportunistic infections in otherwise healthy hosts.

A mouse model of binge alcohol consumption and Burkholderia infection.

BACKGROUND: Binge drinking, an increasingly common form of alcohol consumption, is associated with increased mortality and morbidity; yet, its effects on the immune system's ability to defend against infectious agents are poorly understood. Burkholderia pseudomallei, the causative agent of melioidosis can occur in healthy humans, yet binge alcohol use is progressively being recognized as a major risk factor. Although our previous studies demonstrated that binge alcohol exposure results in reduced alveolar macrophage function and increased Burkholderia virulence in vitro, no experimental studies have investigated the outcomes of binge alcohol on Burkholderia spp. infection in vivo. PRINCIPAL FINDINGS: In this study, we used the close genetic relatives of B. pseudomallei, B. thailandensis E264 and B. vietnamiensis, as useful BSL-2 model systems. Eight-week-old female C57BL/6 mice were administered alcohol comparable to human binge drinking episodes (4.4 g/kg) or PBS intraperitoneally 30 min before a non-lethal intranasal infection. In an initial B. thailandensis infection (3 x 105), bacteria accumulated in the lungs and disseminated to the spleen in alcohol administered mice only, compared with PBS treated mice at 24 h PI. The greatest bacterial load occurred with B. vietnamiensis (1 x 106) in lungs, spleen, and brain tissue by 72 h PI. Pulmonary cytokine expression (TNF-α, GM-CSF) decreased, while splenic cytokine (IL-10) increased in binge drunk mice. Increased lung and brain permeability was observed as early as 2 h post alcohol administration in vivo. Trans-epithelial electrical resistance (TEER) was significantly decreased, while intracellular invasion of non-phagocytic cells increased with 0.2% v/v alcohol exposure in vitro. CONCLUSIONS: Our results indicate that a single binge alcohol dose suppressed innate immune functions and increased the ability of less virulent Burkholderia strains to disseminate through increased barrier permeability and intracellular invasion of non-phagocytic cells.

Effects of binge alcohol exposure on Burkholderia thailandensis-alveolar macrophage interaction.

Alcohol consumption has diverse and well-documented effects on the human immune system and its ability to defend against infective agents. One example is melioidosis, a disease caused by infection with Burkholderia pseudomallei, which is of public health importance in Southeast Asia and Northern Australia, with an expanding global distribution. While B. pseudomallei infections can occur in healthy humans, binge alcohol use is progressively being recognized as a major risk factor. Although binge alcohol consumption has been considered as a risk factor for the development of melioidosis, no experimental studies have investigated the outcomes of alcohol exposure on Burkholderia spp. infection. Therefore, we proposed the use of non-pathogenic B. thailandensis E264 as a useful BSL-1 model system to study the effects of binge alcohol exposure on bacteria and alveolar macrophage interactions. The MH-S alveolar macrophage (AMs) cell line was used to characterize innate immune responses to infection in vitro. Our results showed that alcohol exposure significantly suppressed the uptake and killing of B. thailandensis by AMs. Alveolar macrophages incubated in alcohol (0.08%) for 3 h prior to infection showed significantly lower bacterial uptake at 2 and 8 h post infection. Activated AMs with IFN-γ and pre and post-incubation in alcohol when exposed to B. thailandensis released lower nitric oxide (NO) concentrations, compared to activated AMs with IFN-γ from non-alcoholic controls. As a result, B. thailandensis survival and replication increased ∼2.5-fold compared to controls. The presence of alcohol (1%) also increased bacterial survival within AMs. Alcohol significantly decreased bacterial motility compared to non-alcoholic controls. Increased biofilm formation was observed at 3 and 6 h when bacteria were pre-incubated in (0.08%) alcohol. These results provide insights into binge alcohol consumption, a culturally prevalent risk factor, as a predisposing factor for melioidosis.