Necessary, burdensome, or threatening? Awareness of Black-White disparities in health care access and self-rated health for Black and White Americans.

Awareness of racial health care inequities is one prerequisite to eliminating them. Although extant research has described awareness of racial health care inequities in the United States, the health impacts of such awareness on communities that are most impacted by these inequities remains unknown. Therefore, we examined associations between awareness of Black-White racial health care inequities and self-rated health for Black and White adults in the United States. We used survey data from non-Hispanic Black and White participants (N = 6,449) who responded to the national American Health Values Survey (2015-2016) to test associations between awareness of Black-White inequities in health care and self-rated health. Accurate awareness of health care inequities was associated with 47% higher odds of poorer self-rated health for Black individuals. Inaccurate awareness was associated with 36% higher odds of poorer self-rated health for White individuals. Accurate awareness may be adaptive, yet place an additional burden on Black individuals. Inaccurate awareness may harm White individuals' health. Health care system changes and alleviation of racism-related stress may be preventive supports for the health of Black individuals. Accurate awareness should be a goal for White individuals, not only to prevent health risks, but to also facilitate structural change for racial equity. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Black Young Adult Superwomen in the Face of Gendered Racial Microaggressions: Contextualizing Challenges With Acceptance and Avoidance and Emotional Eating.

BACKGROUND: Black young adult women (ages 18-35) are at disproportionate risk for obesity and emotional eating. Emotional eating interventions target psychological flexibility, such as reducing experiential avoidance and increasing acceptance of food-related thoughts. Yet Black women face gendered racism, and some endorse roles that reduce psychological flexibility, such as the superwoman schema role. Culturally centered stress and coping has often been overlooked, leading to an incomplete understanding of processes that engender emotional eating and the implications for appropriate and effective interventions for Black young adult women. PURPOSE: We investigated direct and indirect pathways of associations between stress from gendered racial microaggressions to emotional eating through the endorsement of superwoman schema and two aspects of psychological flexibility. METHODS: Black young adult women (N = 504; Mage = 24.72; 75.2% African American; 98.4% cisgender) participated in an online survey wherein they reported demographics, stress from gendered racial microaggressions, superwoman schema, experiential avoidance, acceptance of food-related thoughts, and emotional eating. Path analysis was conducted to examine direct and indirect effects. RESULTS: Results provided evidence for indirect associations between more stress from gendered racial microaggressions and more emotional eating. More stress was associated with greater endorsement of the superwoman schema which was associated with more experiential avoidance and less acceptance of food-related thoughts, which were each associated with more emotional eating. CONCLUSIONS: Endorsement of superwoman schema and concomitant avoidance and less acceptance may be one way that gendered racial stress propels emotional eating. Future research could test intervention components that disrupt this path.

Emotional eating is eating in order to alleviate negative emotions, like those from stress. Black young adult women face particular forms of stress from being mistreated at the intersection of their race and gender. This research was needed to better understand processes that engender emotional eating for Black young adult women so that appropriate and effective interventions can be developed for this group. In this correlational study, Black young adult women (ages 18­35) completed an online survey wherein they answered questions about their experiences, thoughts, and behaviors. The study results indicated that stress from mistreatment due to being a Black woman was associated with endorsing a need to be strong. This need to be strong was associated with avoiding experiences that may lead to negative emotional states and being less accepting of distressing thoughts about food. More avoidance and less acceptance were each associated with more emotional eating. Therefore, if emotional eating or obesity-related interventions already target acceptance and avoidance, but do not reference or contextualize them for Black young adult women­particularly in terms of stress from mistreatment as a Black woman and the need to be strong­such interventions may be less effective.

Intersections of Racial/Ethnic and Religious Identities on Bodily Well-Being for Black College-Attending Emerging Adults.

Black undergraduates face threats to healthy weight and body image (i.e., bodily well-being). Having a strong racial/ethnic identity can promote health during emerging adulthood. However, less is known about the intersections of racial/ethnic and religious identities on the bodily well-being of Black college-attending emerging adults, despite evidence to indicate that aspects of religiosity are also associated with health. We use quantitative data from 767 Black college-attending emerging adults in the Multi-University Study of Identity and Culture to examine the independent contributions of racial/ethnic and religious identity for bodily health, and test a potential interaction between racial/ethnic and religious identity on bodily health outcomes. Results from a multivariate linear regression model indicate that Black college-attending emerging adults with both high religious identity and high racial/ethnic identity exploration had higher body mass index and less positive body image. Findings suggest ways to strengthen the development of culturally appropriate public health prevention and intervention efforts that target body image and weight for Black college-attending emerging adults. IMPACT STATEMENT: Black college-attending emerging adults face challenges to their health, particularly threats to healthy weight and body image during this period of psychosocial transitions. The developmental process of navigating racial/ethnic and religious identities during this time raises challenges and opportunities for health promotion for this population. Yet, research that explores the role of these identities remains scarce. We found that Black college-attending emerging adults had higher body mass index and more negative body image when they reported more racial/ethnic identity exploration coupled with higher religious identities. Results shed light on the complex ways that navigating both racial/ethnic and religious identities may put some Black college-attending emerging adults at greater health risk. Health education and promotion practice focused on improving Black emerging adult health in college contexts should ensure that behavioral interventions are appropriately nuanced and situated in these populations' developmental and cultural considerations.

Blood Serum Affects Polysaccharide Production and Surface Protein Expression in S. Aureus.

BACKGROUND: S. aureus biofilm serves a major role in pathogenesis. Two of the major components of bacterial biofilm are Polysaccharides intercellular adhesions (PIA) and surface proteins. It is not known how PIA and surface proteins expressions are affected in presence of blood serum. Analyses of surface proteins expressions will provide more effective biomarker discovery that might lead to development of antimicrobial therapeutics to meet the challenges of biofilm-related infections. METHOD: Secondary cultures of S. aureus Philips, a biofilm-forming bacterium, were generated by inoculating 1 ml of overnight culture into 50 ml of TSB. Bacteria were cultured at several concentrations of blood serum and found that 12.5% supplemented blood serum provide s similar growth curve as normal TSB (100%). One and 2 D SASPAGE were used to separate proteins and the differentially expressed proteins were identified by nano-LC/MS. RESULTS: Polysaccharide intercellular adhesions production was significantly increased due to the addition of blood serum in the media. We also identified two serum proteins, apolipoprotein and globulin (Fc and Fab), that remained attached with the membrane fraction of bacterial proteins. CONCLUSION: These results have strongly demonstrated that blood serum influences the exopolysaccharide expression in S. aureus.

Proteome Analyses of Staphylococcus aureus Biofilm at Elevated Levels of NaCl.

Our studies demonstrate that sodium chloride (NaCl) induces changes in biofilm, mediated by increased production of polysaccharides intercellular adhesion (PIA). We identified 12 proteins that showed higher abundance in increased level of NaCl. This includes one important protein (IsaA) known to be associated with biofilm stability. In addition, we also found higher abundance of a cold shock protein, CspA, at higher NaCl. We have also identified several other proteins that are differentially expressed to the elevated levels of NaCl and mapped them in the regulatory pathways of PIA. The majority of proteins are involved with various aspects bacterial metabolic function. Our results demonstrated that NaCl influences gene regulatory networks controlling exopolysaccharide expression.

White Matter Tracts Connected to the Medial Temporal Lobe Support the Development of Mnemonic Control.

One of the most important factors driving the development of memory during childhood is mnemonic control, or the capacity to initiate and maintain the processes that guide encoding and retrieval operations. The ability to selectively attend to and encode relevant stimuli is a particularly useful form of mnemonic control, and is one that undergoes marked improvement over childhood. We hypothesized that structural integrity of white matter tracts, in particular those connecting medial temporal lobe memory regions to other cortical areas, and/or those connecting frontal and parietal control regions, should contribute to successful mnemonic control. To test this hypothesis, we examined the relationship between structural integrity of selected white matter tracts and an experimental measure of mnemonic control, involving enhancement of memory by attention at encoding, in 116 children aged 7-11 and 25 young adults. We observed a positive relationship between integrity of uncinate fasciculus and mnemonic enhancement across age groups. In adults, but not in children, we also observed an association between mnemonic enhancement and integrity of ventral cingulum bundle and ventral fornix/fimbria. Integrity of fronto-parietal tracts, including dorsal cingulum and superior longitudinal fasciculus, was unrelated to mnemonic enhancement.

Proteomic analysis of Staphylococcus aureus biofilm cells grown under physiologically relevant fluid shear stress conditions.

BACKGROUND: The biofilm forming bacterium Staphylococcus aureus is responsible for maladies ranging from severe skin infection to major diseases such as bacteremia, endocarditis and osteomyelitis. A flow displacement system was used to grow S. aureus biofilms in four physiologically relevant fluid shear rates (50, 100, 500 and 1000 s(-1)) to identify proteins that are associated with biofilm. RESULTS: Global protein expressions from the membrane and cytosolic fractions of S. aureus biofilm cells grown under the above shear rate conditions are reported. Sixteen proteins in the membrane-enriched fraction and eight proteins in the cytosolic fraction showed significantly altered expression (p < 0.05) under increasing fluid shear. These 24 proteins were identified using nano-LC-ESI-MS/MS. They were found to be associated with various metabolic functions such as glycolysis / TCA pathways, protein synthesis and stress tolerance. Increased fluid shear stress did not influence the expression of two important surface binding proteins: fibronectin-binding and collagen-binding proteins. CONCLUSIONS: The reported data suggest that while the general metabolic function of the sessile bacteria is minimal under high fluid shear stress conditions, they seem to retain the binding capacity to initiate new infections.

Fluorescent silica particles for monitoring oxygen levels in three-dimensional heterogeneous cellular structures.

Bacterial biofilms are a major obstacle challenging the development of more effective therapies to treat implant infections. Oxygen availability to bacterial cells has been implicated in biofilm formation and planktonic cell detachment; however, there are insufficient tools available to measure oxygen concentrations within complex three-dimensional structures with ∼ 1 µm resolution. Such measurements may complement measures of biofilm structure and cell activity to provide a more comprehensive understanding of biofilm biology. Thus, we developed oxygen-sensing microparticles specifically designed to characterize oxygen transport through the volume of bacterial biofilms. The Stöber method was used to synthesize monodisperse silica microparticles of approximately the same size as a bacterium (∼ 1 µm). Two fluorophores, oxygen-sensitive Ru(Ph(2) phen(3))Cl(2), and the reference fluorophore Nile blue chloride were immobilized on the surface of the particles. We demonstrate application of the microparticles toward measuring the oxygen concentration profiles within a live Staphylococcus aureus biofilm.

Staphylococcal presence alters thrombus formation under physiological shear conditions in whole blood studies.

The ability of platelets to aggregate at a site of injury and form a thrombus is central to normal hemostasis and host survival. Staphylococcus aureus is a major pathogenic organism that has been described as interacting with platelets and promoting platelet aggregation. However, the fundamental effects of bacterial presence on thrombus formation are poorly understood. In this study, we quantify thrombus formation in whole blood in the presence and absence of S. aureus under physiological shear conditions. Using confocal microscopy we observed that S. aureus causes a reduction in thrombus volumes and alters the morphological structure of the growing thrombi.

Erosion from Staphylococcus aureus biofilms grown under physiologically relevant fluid shear forces yields bacterial cells with reduced avidity to collagen.

An estimated 65% of infective diseases are associated with the presence of bacterial biofilms. Biofilm-issued planktonic cells promote blood-borne, secondary sites of infection by the inoculation of the infected sites with bacteria from the intravascular space. To investigate the potential role of early detachment events in initiating secondary infections, we studied the phenotypic attributes of Staphylococcus aureus planktonic cells eroding from biofilms with respect to expression of the collagen adhesin, CNA. The collagen-binding abilities of S. aureus have been correlated to the development of osteomyelitis and septic arthritis. In this study, we focused on the impact of CNA expression on S. aureus adhesion to immobilized collagen in vitro under physiologically relevant shear forces. In contrast to the growth phase-dependent adhesion properties characteristic of S. aureus cells grown in suspension, eroding planktonic cells expressed invariant and lower effective adhesion rates regardless of the age of the biofilm from which they originated. These results correlated directly with the surface expression level of CNA. However, subsequent analysis revealed no qualitative differences between biofilms initiated with suspension cells and secondary biofilms initiated with biofilm-shed planktonic cells. Taken together, our findings suggest that, despite their low levels of CNA expression, S. aureus planktonic cells shed from biofilms retain the capacity for metastatic spread and the initiation of secondary infection. These findings demonstrate the need for a better understanding of the phenotypic properties of eroding planktonic cells, which could lead to new therapeutic strategies to target secondary infections.

Staphylococcus aureus adhesion via Spa, ClfA, and SdrCDE to immobilized platelets demonstrates shear-dependent behavior.

OBJECTIVE: The objective of this study is to delineate the molecular mechanisms responsible for Staphylococcus aureus-platelet adhesion as a function of physiologically relevant wall shear stresses. METHODS AND RESULTS: A parallel plate flow chamber was used to quantify adhesion of wild-type, Spa-, ClfA- and SdrCDE- strains to immobilized platelet layers. In the absence of plasma, adhesion increases with increasing wall shear rate from 100 to 5000 seconds(-1). The presence of plasma significantly enhances adhesion at all shear levels. Addition of exogenous fibrinogen yields adhesion levels similar to plasma in the lower shear regimes, but has a diminishing effect on potentiating adhesion at higher shear rates. Alternatively, as shear rate increases von Willebrand factor (VWF) plays an increasingly significant role in mediating binding. CONCLUSIONS: Addition of plasma proteins potentiates S aureus-platelet interactions at all shear rates examined. Whereas fibrinogen plays a significant role in all shear regimes, VWF mediation becomes increasingly important as wall shear rate increases. Fibrinogen binding is dependent on bacterial adhesins ClfA and SdrCDE whereas Spa is the dominant receptor for VWF.

Characteristics of new Staphylococcus aureus-RBC adhesion mechanism independent of fibrinogen and IgG under hydrodynamic shear conditions.

Staphylococcus aureus infection begins when bacterial cells circulating in blood adhere to components of the extracellular matrix or endothelial cells of the host and initiate colonization. S. aureus is known to exhibit extensive interactions with platelets. S. aureus is also known to bind to red blood cells (RBCs) in the presence of plasma proteins, such as fibrinogen and IgG. Herein we report a new binding mechanism of S. aureus to RBC independent of those plasma proteins. To characterize the new adhesion mechanism, we experimentally examine the binding kinetics and molecular constituents mediating the new adhesive interactions between S. aureus and RBCs under defined shear conditions. The results demonstrate that the receptors for fibrinogen (clumping factor A) and IgG (protein A) of S. aureus are not involved in the adhesion. S. aureus binds to RBCs with maximal adhesion at the shear rate 100 s(-1) and decreasing adhesion with increasing shear. The heteroaggregates formed after shear are stable when subjected to the shear rate 2,000 s(-1), indicating that intercellular contact time rather than shear forces controls the adhesion at high shear. S. aureus binding to RBC requires plasma, and 10% plasma is sufficient for maximal adhesion. Plasma proteins involved in the cell-cell adhesion, such as fibrinogen, fibronectin, von Willebrand factor, IgG, thrombospondin, laminin, and vitronectin are not involved in the observed adhesion. The extent of heteroaggregation is dramatically reduced on RBC treatment with trypsin, chymotrypsin, or neuraminidase, suggesting that the receptor(s) mediating the heteroaggregation process is a sialylated glycoprotein on RBC surface. Adhesion is divalent cation dependent and also blocked by heparin. This work demonstrates a new mechanism of S. aureus-RBC binding under hydrodynamic shear conditions via unknown RBC sialoglycoprotein(s). The binding requires plasma protein(s) other than fibrinogen or IgG and does not involve the S. aureus adhesins clumping factor A or protein A.

Proteome analysis of membrane and cell wall associated proteins from Staphylococcus aureus.

Pathogenesis of Staphylococcus aureus, an opportunistic human pathogen, is complex and involves many virulence factors including an array of surface proteins (adhesins) that promote bacterial interactions with extracellular matrix components. A better understanding of these interactions can be achieved by studying the expression of membrane and cell wall associated proteins using a proteome analysis approach. To accomplish this, our goal here was to construct a reference map of membrane and cell wall associated proteins for S. aureus. Various lytic and solubilization methods have been tested to identify a suitable methodology for detection of these proteins in two-dimensional electrophoresis (2DE). Results demonstrate that cell lysis with lysostaphin, which lyses staphylococcal peptidoglycan, followed by solubilization with urea, thiourea, amidosulfobetaine 14 (ASB 14) and dithiothreitol (DTT) is an effective method, yielding a sample comprising proteins of wide molecular ranges and isoelectric points with minimum contamination from cytosolic proteins. Mass spectrometric analysis was employed to identify the membrane and cell surface proteins present in the sample and consequently an initial proteomic map of membrane and cell wall associated proteins for S. aureus is presented.

Fluid shear regulates the kinetics and receptor specificity of Staphylococcus aureus binding to activated platelets.

The interaction between surface components on the invading pathogen and host cells such as platelets plays a key role in the regulation of endovascular infections. However, the mechanisms mediating Staphylococcus aureus binding to platelets under shear remain largely unknown. This study was designed to investigate the kinetics and molecular requirements of platelet-S. aureus interactions in bulk suspensions subjected to a uniform shear field. Hydrodynamic shear-induced collisions augment platelet-S. aureus binding, which is further potentiated by platelet activation with stromal derived factor-1beta. Peak adhesion efficiency occurs at low shear (100 s(-1)) and decreases with increasing shear. The molecular interaction of platelet alpha(IIb)beta(3) with bacterial clumping factor A through fibrinogen bridging is necessary for stable bacterial binding to activated platelets under shear. Although this pathway is sufficient at low shear (

Characterization of a protective monoclonal antibody recognizing Staphylococcus aureus MSCRAMM protein clumping factor A.

The Staphylococcus aureus MSCRAMM (microbial surface components recognizing adhesive matrix molecules) protein clumping factor A (ClfA) has been shown to be a critical virulence factor in several experimental models of infection. This report describes the generation, characterization, and in vivo evaluation of a murine monoclonal antibody (MAb) against ClfA. Flow cytometric analysis revealed that MAb 12-9 recognized ClfA protein expressed by all of the clinical S. aureus strains obtained from a variety of sources. In assays measuring whole-cell S. aureus binding to human fibrinogen, MAb 12-9 inhibited S. aureus binding by over 90% and displaced up to 35% of the previously adherent S. aureus bacteria. Furthermore, a single infusion of MAb 12-9 was protective against an intravenous challenge with a methicillin-resistant strain of S. aureus in a murine sepsis model (P < 0.0001). These data suggest that anti-ClfA MAb 12-9 should be further investigated as a novel immunotherapy for the treatment and prevention of life-threatening S. aureus infections.

Quantification of staphylococcal-collagen binding interactions in whole blood by use of a confocal microscopy shear-adhesion assay.

In bloodborne staphylococcal infections, bacteria and platelets often combine, forming thrombi on the subendothelium, where collagen is exposed. In this process, the collagen serves as a potential binding surface for Staphylococcus aureus. However, the extent and importance of S. aureus-collagen binding interactions in the development of infected thrombi is uncertain. We quantified S. aureus adhesion to collagen in a whole-blood suspension under defined physiologically relevant fluid shear conditions. S. aureus-collagen binding interactions, mediated by both the S. aureus collagen adhesin (CNA) and protein A-von Willebrand factor (vWf), were evaluated using mutant strains and antibody-blocking techniques. The position of adherent bacteria (at the collagen surface or above the surface in the platelet aggregate) was measured using confocal laser microscopy. Results demonstrated significant CNA-collagen interactions and protein A-vWf-collagen binding interactions under physiological shear conditions. We conclude that collagen binding interactions are important in the development of infected thrombi.

Fluid shear contributions to bacteria cell detachment initiated by a monoclonal antibody.

Receptor-mediated adhesion of bacteria to biological surfaces is a significant step leading to infection. Due to an increase in bacterial antibiotic resistance, novel methods to block and disrupt these specific interactions have gained considerable interest as possible therapeutic strategies. Recently, several monoclonal antibodies specific for the Staphylococcus aureus collagen receptor demonstrated specialized ability to displace attached cells from collagen in static assays. In this study, we experimentally examine the monoclonal antibody detachment functionality under physiological shear conditions to evaluate the role of this parameter in the detachment process. The detachment of staphylococci from collagen was quantified in real-time using a parallel plate flow chamber, phase contrast video-microscopy and digital image processing. The results demonstrate a unimodal dependence of detachment on fluid wall shear rate. The observed decrease in effective detachment rate with increasing force at the highest shear levels evaluated is counterintuitive and has not been previously demonstrated. Several possible mechanisms of this result are discussed.

Quantifying the temporal expression of the Staphylococcus aureus collagen adhesin.

The initial event in the pathogeneis of most Staphylococcus aureus infections is attachment to biological substrates in vivo using specific protein-protein interactions. We previously quantified the temporal expression of the collagen adhesin (CNA) on S. aureus Phillips and demonstrated that dynamic adhesin capacity to collagen is strongly influenced by the adhesin density. However, most strains of S. aureus express an extensive amount of Protein A on the surface, presenting a complication when using immunofluorescence to quantify specific surface adhesins. In this study, an improved adhesin quantification method is presented that accommodates variable surface Protein A levels. This method was used to examine the temporal expression of CNA on six S. aureus strains. Collagen adhesin levels varied with growth phase and strain, ranging from 1096 to 8950 copies per cell. Five of the six strains exhibited a temporal expression pattern similar to that previously reported for S. aureus Phillips.