Positive epidemiology, revisited: The case for centering human rights and economic justice

In recent years, a growing body of research in positive epidemiology has sought to expand the traditional focus of epidemiologic research beyond risk factors for disease and towards a more holistic understanding of health that includes the study of positive assets that shape well-being more broadly. While this paradigm shift holds great promise for transforming people's lives for the better, it is also critiqued for showcasing decontextualized perspectives that could cause great harm to the public's health if translated uncritically into population-based interventions. In this commentary, we argue for orienting positive epidemiology within a human rights and economic justice framework to mitigate this threat and discuss two examples of previously proposed health assets (religious involvement and marriage) that demonstrate the urgent need for positive epidemiologic research to center health equity. Finally, to advance the field, we provide recommendations for how future research can address shortcomings of the extant literature by moving from individual-level applications to societal-level approaches. In doing so, we believe that positive epidemiology can be transformed into a powerful force for health equity.

Structural determinants of the direct inhibition of GIRK channels by Sigma-1 receptor antagonist

G-protein-gated inward rectifier K+ (GIRK) channels play a critical role in the regulation of the excitability of cardiomyocytes and neurons and include GIRK1, GIRK2, GIRK3 and GIRK4 subfamily members. BD1047 dihydrobromide (BD1047) is one of the representative antagonists of the multifunctional Sigma-1 receptor (S1R). In the analysis of the effect of BD1047 on the regulation of Gi-coupled receptors by S1R using GIRK channel as an effector, we observed that BD1047, as well as BD1063, directly inhibited GIRK currents even in the absence of S1R and in a voltage-independent manner. Thus, we aimed to clarify the effect of BD1047 on GIRK channels and identify the structural determinants. By electrophysiological recordings in Xenopus oocytes, we observed that BD1047 directly inhibited GIRK channel currents, producing a much stronger inhibition of GIRK4 compared to GIRK2. It also inhibited ACh-induced native GIRK current in isolated rat atrial myocytes. Chimeric and mutagenesis studies of GIRK2 and GIRK4 combined with molecular docking analysis demonstrated the importance of Leu77 and Leu84 within the cytoplasmic, proximal N-terminal region and Glu147 within the pore-forming region of GIRK4 for inhibition by BD1047. The activator of GIRK channels, ivermectin, competed with BD1047 at Leu77 on GIRK4. This study provides us with a novel inhibitor of GIRK channels and information for developing pharmacological treatments for GIRK4-associated diseases.

Structural determinants underlying high-temperature adaptation of thermophilic xylanase from hot-spring microorganisms

Thermophilic xylanases from hot-spring microorganisms play potential biological and industrial applications for renewable and sustainable social development. However, high-temperature adaptation mechanisms of these thermophilic xylanases remain elusive at the molecular and evolutionary levels. Here, two recently reported xylanases, named XynDRTY1 and XynM1, from hot springs were subjected to molecular dynamics (MD) simulations at a series of temperature gradients and comparatively analyzed in comparison with the evolutionary background of the xylanase family. Comparative analysis of MD trajectories revealed that the XynM1 exhibits smaller structural dynamics and greater thermal stability than the XynDRTY1, although both share a similar fold architecture with structural differences in the βα_loops. Local regions whose conformational flexibility and regular secondary structure exhibited differences as temperature increases were closely related to the high-temperature adaptation of xylanase, implying that stabilization of these regions is a feasible strategy to improve the thermal stability of xylanases. Furthermore, coevolutionary information from the xylanase family further specified the structural basis of xylanases. Thanks to these results about the sequence, structure, and dynamics of thermophilic xylanases from hot springs, a series of high-temperature-related structural determinants were resolved to promote understanding of the molecular mechanism of xylanase high-temperature adaptation and to provide direct assistance in the improvement of xylanase thermal stability.

The structural and social determinants of Alzheimer's disease related dementias

INTRODUCTION

The projected growth of Alzheimer's disease (AD) and AD-related dementia (ADRD) cases by midcentury has expanded the research field and impelled new lines of inquiry into structural and social determinants of health (S/SDOH) as fundamental drivers of disparities in AD/ADRD.

METHODS

In this review, we employ Bronfenbrenner's ecological systems theory as a framework to posit how S/SDOH impact AD/ADRD risk and outcomes.

RESULTS

Bronfenbrenner defined the "macrosystem" as the realm of power (structural) systems that drive S/SDOH and that are the root cause of health disparities. These root causes have been discussed little to date in relation to AD/ADRD, and thus, macrosystem influences, such as racism, classism, sexism, and homophobia, are the emphasis in this paper.

DISCUSSION

Under Bronfenbrenner's macrosystem framework, we highlight key quantitative and qualitative studies linking S/SDOH with AD/ADRD, identify scientific gaps in the literature, and propose guidance for future research.

HIGHLIGHTS

Ecological systems theory links structural/social determinants to AD/ADRD. Structural/social determinants accrue and interact over the life course to impact AD/ADRD. Macrosystem is made up of societal norms, beliefs, values, and practices (e.g., laws). Most macro-level determinants have been understudied in the AD/ADRD literature.

Protecting and promoting the rights of the 'reserve army of labour': A policy analysis of structural determinants of migrant worker health in Pakistan and Qatar

Labour migrants who travel overseas for employment can face deep health inequities driven in a large part by upstream social and structural determinants of health. We sought to study the 'labour migrant health ecosystem' between one sending country (Pakistan) and one host country (Qatar), with a focus on how the ecosystem realizes the rights of labour migrants when addressing the social and structural determinants (e.g. housing, employment law, etc) of health. Study objectives were to: (1) undertake an in-depth review of policies addressing the structural and social determinants of the health of labour migrants in both Pakistan and Qatar, analysing the extent to which these policies align with global guidance, are equity-focused and have clear accountability mechanisms in place; and (2) explore national stakeholder perspectives on priority setting for labour migrant health. We used a mixed methods approach, combining policy content analysis and interviews with stakeholders in both countries. We found a wide range of guidance from the multilateral system on addressing structural determinants of the health of labour migrants. However, policy responses in Pakistan and Qatar contained a limited number of these recommended interventions and had low implementation potential and minimal reference to gender, equity and rights. Key national stakeholders had few political incentives to act and lacked inter-country coordination mechanisms required for an effective and cohesive response to labour migrant health issues. Effectively addressing such determinants to achieve health equity for labour migrants will depend on a shift in governments' attitudes towards migrants-from a reserve army of transient, replaceable economic resources to rights-holding members of society deserving of equality, dignity and respect.

Neighborhood segregation and cognitive change: Multi-Ethnic Study of Atherosclerosis

INTRODUCTION

We investigated associations between neighborhood racial/ethnic segregation and cognitive change.

METHODS

We used data (n = 1712) from the Multi-Ethnic Study of Atherosclerosis. Racial/ethnic segregation was assessed using Getis-Ord (Gi*) z-scores based on American Community Survey Census tract data (higher Gi* = greater spatial clustering of participant's race/ethnicity). Global cognition and processing speed were assessed twice, 6 years apart. Adjusted multilevel linear regression tested associations between Gi* z-scores and cognition. Effect modification by race/ethnicity, income, education, neighborhood socioeconomic status, and neighborhood social support was tested.

RESULTS

Participants were on average 67 years old; 43% were White, 11% Chinese, 29% African American/Black, 17% Hispanic; 40% had high neighborhood segregation (Gi* > 1.96). African American/Black participants with greater neighborhood segregation had greater processing speed decline in stratified analyses, but no interactions were significant.

DISCUSSION

Segregation was associated with greater processing speed declines among African American/Black participants. Additional follow-ups and comprehensive cognitive batteries may further elucidate these findings.

HIGHLIGHTS

A study of neighborhood racial/ethnic segregation and change in cognition. Study was based on a racially and geographically diverse, population-based cohort of older adults. Racial/ethnic segregation (clustering) was measured by the Getis-ord (Gi*) statistic. We saw faster processing speed decline among Black individuals in segregated neighborhoods.

Racial disparities in uterine fibroids and endometriosis: a systematic review and application of social, structural, and political context

IMPORTANCE

Uterine fibroids and endometriosis are 2 of the leading causes of morbidity among reproductive-aged women. There are significant racial disparities in disease prevalence, incidence, age of onset, and treatment profile in fibroids. The data on endometriosis are less clear.

OBJECTIVE

To conduct a systematic review of racial disparities in prevalence of uterine fibroids and endometriosis in the United States and summarize the literature on these 2 highly prevalent benign gynecologic conditions using a framework that explicitly incorporates and acknowledges the social, structural, and political contexts as a root cause of racial disparities between Black and White women.

EVIDENCE REVIEW

A systematic review regarding racial disparities in prevalence of fibroids and endometriosis was conducted separately. Two separate searches were conducted in PubMed to identify relevant original research manuscripts and prior systematic reviews regarding racial disparities in uterine fibroids and endometriosis using standardized search terms. In addition, we conducted a structured literature search to provide social, structural, and political context of the disparities.

FINDINGS

A systematic review of the literature indicated that the prevalence of uterine fibroids was consistently higher in Black than in White women with the magnitude of the difference varying depending on population and case definition. Prevalence of endometriosis varied considerably depending on the base population and case definition, but was the same or lower among Black vs. White women. As a result of the social, structural, and political context in the United States, Black women disproportionately experience a range of exposures across the life course that may contribute to their increased uterine fibroid incidence, prevalence, and severity of uterine fibroids. However, data suggest no racial difference in the incidence of endometriosis. Nevertheless, Black women with fibroids or endometriosis experience worse clinical and surgical outcomes than their White counterparts.

CONCLUSION AND RELEVANCE

Racial disparities in uterine fibroids and endometriosis can be linked with differential exposures to suspected etiologic agents, lack of adequate access to health care, including highly skilled gynecologic surgeons, and bias and discrimination within the health care system. Eliminating these racial disparities will require solutions that address root causes of health disparities through policy, education and programs to ensure that all patients receive culturally- and structurally-competent care.

Invisibility as a structural determinant: Mortality outcomes of Asians and Pacific Islanders experiencing homelessness

Introduction

Asians and Pacific Islanders (APIs) who are experiencing homelessness are situated in a social intersection that has rendered them unrecognized and therefore vulnerable. There has been increasing attention to racial disparities in homelessness, but research into API homelessness is exceedingly rare, despite rapidly growing populations. The purpose of this study is to examine the causes of death among APIs who died while homeless in Santa Clara County (SCC) and compare these causes to other racial groups.

Materials and methods

We report on data obtained from the SCC Medical Examiner-Coroner's Office on unhoused people's deaths that occurred between 2011 and 2021 (n = 1,394), including data on deaths of APIs experiencing homelessness (n = 87).

Results

APIs comprised 6.2% of total deaths of unhoused people. APIs died less often of causes related to drug/alcohol use than all other racial groups (24.1, compared to 39.3%), and there was a trend toward more API deaths from injuries or illnesses. When APIs were disaggregated into sub-groups (East/Southeast Asian, South Asian, Pacific Islander), there were notable mortality differences in cause of death, age, and sex.

Discussion

We argue that invisibility is a structural determinant of health that homeless APIs face. Though relatively small in numbers, APIs who are invisible may experience increased social isolation and, subsequently, specific increased mortality risks. To understand the health outcomes of unhoused APIs, it is essential that researchers and policymakers recognize API homelessness and gather and report disaggregated races and ethnicities.

Sexual Orientation-Related Nondiscrimination Laws and Maternal Hypertension Among Black and White U.S. Women

Background: Black women and sexual minority women are more likely to report adverse maternal health. Little research has investigated maternal health disparities at the intersection of race/ethnicity and sexual orientation or the mechanisms that contribute to these disparities. Materials and Methods: We analyzed data from the National Longitudinal Study of Adolescent to Adult Health. Our sample was restricted to Black and White women who had at least one live birth and were followed-up in Wave V of the data (n = 3,396). We used multivariable logistic regression to analyze the associations between race, sexual orientation identity, and a four-item state-level index of sexual orientation-related nondiscrimination laws. Results: We found that higher numbers of state-level sexual orientation-related nondiscrimination laws were associated with lower risk of maternal hypertension among U.S. women overall (odds ratio [OR] = 0.82, 95% confidence interval [CI] 0.73-0.93), and Black women had a higher risk of maternal hypertension relative to White women (OR = 1.32, 95% CI 1.00-1.79). Interactions between race, sexual orientation identity, and sexual orientation-related policies show that, regardless of sexual orientation identity, sexual orientation-related nondiscrimination laws were associated with a lower risk of maternal hypertension among White mothers (OR = 0.80, 95% CI 0.70-0.92). However, among Black women, these laws were associated with a lower risk of maternal hypertension among lesbian and bisexual women (OR = 0.18, 95% CI 0.05-0.68) only. Conclusions: Laws that prevent discrimination related to sexual orientation in various societal domains may play an important role in improving maternal health outcomes among White women in general and Black lesbian and bisexual women in particular.

Investigating a key structural determinant of health, racism, and related social determinants of health in Massachusetts during the COVID-19 pandemic

A disproportionate burden of the ongoing COVID-19 pandemic is being shouldered by members of racial and ethnic minorities and socially disadvantaged communities. Structural and social determinants of health have been recognized as key contributors to the inequalities observed. Racism, a major structural determinant of health that patterns related social determinants of health, in the USA, warrants further investigation. In this perspective piece we provide an overview of the historical context of racism, followed by preliminary findings from the ongoing COVIDStory study-a cross-sectional study addressing perceptions of COVID-19 and COVID-19 research-that highlights the experiences of non-Hispanic Black and Hispanic identifying adult participants, residing in Worcester Massachusetts, during the COVID-19 pandemic. We then discuss these findings in the context of current and past research considering racism and relevant social determinants of health. Our study results suggest that racism and its residuals (residential segregation, economic insecurity, discrimination, bias, and vigilance) are modern challenges for non-Hispanic Black and Hispanic participants, and these findings are supported by the existing literature. It is our hope that this perspective piece provides additional evidence for action on structural and social determinants affecting the health of minoritized people, especially those living in Massachusetts.

Linking suicide and social determinants of health in South Korea: An investigation of structural determinants

Introduction

Studies have shown that suicide is closely related to various social factors. However, due to the restriction in the data scale, our understanding of these social factors is still limited. We propose a conceptual framework for understanding social determinants of suicide at the national level and investigate the relationships between structural determinants (i.e., gender, employment statuses, and occupation) and suicide outcomes (i.e., types of suicide, places of suicide, suicide methods, and warning signs) in South Korea.

Methods

We linked a national-level suicide registry from the Korea Psychological Autopsy Center with the Social Determinants of Health framework proposed by the World Health Organization's Commission on Social Determinants of Health.

Results

First, male and female suicide victims have clear differences in their typical suicide methods (fire vs. drug overdose), primary warning signs (verbal vs. mood), and places of death (suburb vs. home). Second, employees accounted for the largest proportion of murder-suicides (>30%). The proportion of students was much higher for joint suicides than for individual suicides and murder-suicides. Third, among individuals choosing pesticides as their suicide method, over 50% were primary workers. In terms of drug overdoses, professionals and laborers accounted for the largest percentage; the former also constituted the largest proportion in the method of jumping from heights.

Conclusion

A clear connection exists between the investigated structural factors and various suicide outcomes, with gender, social class, and occupation all impacting suicide.

Assessing the Influence of Food Insecurity and Retail Environments as a Proxy for Structural Racism on the COVID-19 Pandemic in an Urban Setting

A collaborative partnership launched the Great Grocer Project (GGP) in March 2021 in Detroit, Michigan where health inequities, including deaths due to COVID-19, have historically been politically determined and informed by socially entrenched norms. Institutional and structural racism has contributed to a lack of diversity in store ownership among Detroit grocers and limited access to high-quality, affordable healthy foods as well as disparate food insecurity among Detroit residents. The GGP seeks to promote Detroit's healthy grocers to improve community health and economic vitality through research, programs, and policies that have the potential to advance health equity. A cross-sectional design was used to explore relationships between scores from the Nutrition Environment Measures Surveys-Stores (NEMS-S) in 62 stores and city-level data of COVID-19 cases and deaths as well as calls to 211 for food assistance. Regression and predictive analyses were conducted at the ZIP code level throughout the city to determine a relationship between the community food environment and food insecurity on COVID-19 cases and deaths. COVID-19 cases and deaths contributed to greater food insecurity. The use of ZIP code data and the small sample size were limitations within this study. Causation could not be determined in this study; therefore, further analyses should explore the potential effects of individual grocery stores on COVID-related outcomes since a cluster of high-scoring NEMS-S stores and calls to 211 for food security resources inferred a potential protective factor. Poor nutrition has been shown to be associated with increased hospitalizations and deaths due to COVID-19. It is important to understand if a limited food environment can also have a negative effect on COVID-19 rates and deaths. Lessons learned from Detroit could have implications for other communities in using food environment improvements to prevent an uptick in food insecurity and deaths due to COVID-19 and other coronaviruses.

Reimagining Preexposure Prophylaxis Provision for Women in the United States

Structural determinants of health drive inequities in the acquisition of human immunodeficiency virus (HIV) and the use of preexposure prophylaxis (PrEP) for HIV prevention among cisgender women in the United States. However, current PrEP clinical guidance and implementation paradigms largely focus on individual behaviors and characteristics, resulting in missed opportunities to improve PrEP access, and the implicit transferring of prevention work from health systems to individuals. In this viewpoint article, we outline ways to apply a structural lens to clinical guidance and PrEP implementation for women and propose areas for future work.

Other Statistical Lives

While recent scholarship has considered how algorithmic risk assessment is both shaped by and impacts social inequity, public health has not adequately considered the ways that statistical risk functions in the social world. Drawing on ethnographic and interview data collected in interpersonal violence prevention programs, this manuscript theorizes three "other lives" of statistically produced risk factors: the past lives of risk factors as quantifiable lived experience, the professional lives of risk as a practical vocabulary shaping social interactions, and the missing lives of risk as a meaningful social category for those marked as at risk. The manuscript considers how understanding these other lives of statistical risk can help public health scholars better understand barriers to social equity.

Collaborative Social-Epidemiology: A Co-analysis of the Cultural and Structural Determinants of Health for Aboriginal Youth in Victorian Schools

Social-epidemiology that excludes Aboriginal voices often fails to capture the full and complex social worlds of Aboriginal people. Using data from an existing co-designed Victorian government Adolescent Health and Wellbeing Survey (2008/9), we worked with Aboriginal organizations to identify data priorities, select measures, interpret data, and contextualize findings. Using this participatory co-analysis approach, we selected "cultural" and "structural" determinants identified by Aboriginal organizations as important and modelled these using principal component analysis. Resulting components were then modelled using logistic regression to investigate associations with "likely being well" (Kessler-10 score < 20) for 88 Aboriginal adolescents aged 11-17 years. Principal component analysis grouped 11 structural variables into four components and 11 cultural variables into three components. Of these, "grew up in Aboriginal family/community and connected" associated with significantly higher odds of "likely being well" (OR = 2.26 (1.01-5.06), p = 0.046). Conversely, "institutionally imposed family displacement" had significantly lower odds (OR = 0.49 (0.24-0.97), p = 0.040) and "negative police contact and poverty" non-significantly lower odds (OR = 0.53 (0.26-1.06), p = 0.073) for "likely being well". Using a co-analysis participatory approach, the voices of Aboriginal researchers and Aboriginal organizations were able to construct a social world that aligned with their ways of knowing, doing, and being. Findings highlighted institutionally imposed family displacement, policing, and poverty as social sites for health intervention and emphasized the importance of strong Aboriginal families for adolescents.

A three-pocket model for substrate coordination and selectivity by the nucleotide sugar transporters SLC35A1 and SLC35A2

The CMP-sialic acid transporter SLC35A1 and UDP-galactose transporter SLC35A2 are two well-characterized nucleotide sugar transporters with distinctive substrate specificities. Mutations in either induce congenital disorders of glycosylation. Despite the biomedical relevance, mechanisms of substrate specificity are unclear. To address this critical issue, we utilized a structure-guided mutagenesis strategy and assayed a series of SLC35A2 and SLC35A1 mutants using a rescue approach. Our results suggest that three pockets in the central cavity of each transporter provide substrate specificity. The pockets comprise (1) nucleobase (residues E52, K55, and Y214 of SLC35A1; E75, K78, N235, and G239 of SLC35A2); (2) middle (residues Q101, N102, and T260 of SLC35A1; Q125, N126, Q129, Y130, and Q278 of SLC35A2); and (3) sugar (residues K124, T128, S188, and K272 of SLC35A1; K148, T152, S213, and K297 of SLC35A2) pockets. Within these pockets, two components appear to be especially critical for substrate specificity. Y214 (for SLC35A1) and G239 (for SLC35A2) in the nucleobase pocket appear to discriminate cytosine from uracil. Furthermore, Q129 and Q278 of SLC35A2 in the middle pocket appear to interact specifically with the β-phosphate of UDP while the corresponding A105 and A253 residues in SLC35A1 do not interact with CMP, which lacks a β-phosphate. Overall, our findings contribute to a molecular understanding of substrate specificity and coordination in SLC35A1 and SLC35A2, and have important implications for the understanding and treatment of diseases associated with mutations or dysregulations of these two transporters.

Structural determinants of stigma across health and social conditions: a rapid review and conceptual framework to guide future research and intervention

INTRODUCTION

Stigma has been identified as a key determinant of health and health inequities because of its effects on access to health-enabling resources and stress exposure. Though existing reports offer in-depth summaries of the mechanisms through which stigma influences health, a review of evidence on the upstream drivers of stigma across health and social conditions has been missing. The objective of this review is to summarize known structural determinants of stigma experienced across health and social conditions in developed country settings.

METHODS

We conducted a rapid review of the literature. English- and French-language peer-reviewed and grey literature works published after 2008 were identified using MEDLINE, Embase, PsycINFO, Google and Google Scholar. Titles and abstracts were independently screened by two reviewers. Information from relevant publications was extracted, and a thematic analysis of identified determinants was conducted to identify broad domains of structural determinants. A narrative synthesis of study characteristics and identified determinants was conducted.

RESULTS

Of 657 publications identified, 53 were included. Ten domains of structural determinants of stigma were identified: legal frameworks, welfare policies, economic policies, social and built environments, media and marketing, pedagogical factors, health care policies and practices, biomedical technology, diagnostic frameworks and public health interventions. Each domain is defined and summarized, and a conceptual framework for how the identified domains relate to the stigma process is proposed.

CONCLUSION

At least 10 domains of structural factors influence the occurrence of stigma across health and social conditions. These domains can be used to structure policy discussions centred on ways to reduce stigma at the population level.

HIV infection and engagement in HIV care cascade among men who have sex with men and transgender women in Kigali, Rwanda: a cross-sectional study

INTRODUCTION

Given intersecting biological, network and structural risks, men who have sex with men (MSM) and transgender women (TGW) consistently have a high burden of HIV. Although MSM are a key population in Rwanda, there are limited epidemiologic data to guide programming. This study aimed to characterize HIV prevalence and care cascade among MSM and TGW in Kigali.

METHODS

MSM and TGW ≥ 18 years were recruited using respondent-driven sampling (RDS) from March-August 2018 in Kigali. Participants underwent a structured interview including measures of individual, network and structural determinants. HIV and sexually transmitted infections (STI) including syphilis, Neisseria gonorrhoea (NG) and Chlamydia trachomatis (CT) were tested. Viral load was measured for MSM living with HIV. Robust Poisson regression was used to characterize the determinants of HIV infection and engagement in the HIV treatment cascade.

RESULTS

A total of 736 participants were enrolled. The mean age was 27 years (range:18 to 68) and 14% (106) were TGW. HIV prevalence was 10% (RDS-adjusted: 9.2% (95% CI: 6.4 to 12.1)). Unadjusted prevalence of any STI was 20% (147); syphilis: 5.7% (42); CT: 9.1% (67) and NG: 8.8% (65). Anticipated (41%), perceived (36%) and enacted stigmas (45%) were common and higher among TGW (p < 0.001). In multivariable RDS adjusted analysis, higher age (aPR: 1.08 (95% CI: 1.05 to 1.12)) and ever having sex with women (aPR: 3.39 (95% CI: 1.31 to 8.72)) were positively associated with prevalent HIV. Being circumcised (aPR: 0.52 (95% CI: 0.28 to 0.9)) was negatively associated with prevalent HIV infection. Overall, 61% (45/74) of respondents reported knowing their HIV-positive status. Among these, 98% (44/45) reported antiretroviral therapy use (ART); 75% (33/44) were virally suppressed using a cut-off of <200 copies/mL. Of the 29 participants who did not report any previous HIV diagnosis or ART use, 38% (11/29) were virally suppressed. Cumulatively, 59% (44/74) of all participants living with HIV were virally suppressed.

CONCLUSIONS

These data show a high burden of HIV among MSM/TGW in Kigali, Rwanda. Bisexual concurrency was common and associated with prevalent HIV infection, demonstrating the need of comprehensive screening for all sexual practices and preferences in the provision of comprehensive HIV prevention services in Rwanda. Viral suppression was below the UNAIDS target suggesting poor adherence and potential ART resistance. There is a need for adherence support, screening for primary and secondary ART resistance and stigma mitigation interventions to optimize HIV-related outcomes for MSM in Rwanda.

A conserved evolutionary mechanism permits Δ9 desaturation of very-long-chain fatty acyl lipids

Δ9 fatty acyl desaturases introduce a cis-double bond between C9 and C10 of saturated fatty acyl chains. From the crystal structure of the mouse stearoyl-CoA desaturase (mSCD1) it was proposed that Tyr-104, a surface residue located at the distal end of the fatty acyl binding pocket plays a key role in specifying 18C selectivity. We created mSCD1-Y104G to test the hypothesis that eliminating this bulky side chain would create an opening and permit the substrate's methyl end to protrude through the enzyme into the lipid bilayer, facilitating the desaturation of very-long-chain (VLC) substrates. Consistent with this hypothesis, Y104G acquired the ability to desaturate 24C and 26C acyl-CoAs while maintaining its Δ9-regioselectivity. We also investigated two distantly related very-long-chain fatty acyl (VLCFA) desaturases from Arabidopsis, ADS1.2 and ADS1.4, which have Ala and Gly, respectively, in place of the gatekeeping Tyr found in mSCD1. Substitution of Tyr for Ala and Gly in ADS1.2 and ADS1.4, respectively, blocked their ability to desaturate VLCFAs. Further, we identified a pair of fungal desaturase homologs which contained either an Ile or a Gly at this location and showed that only the Gly-containing desaturase was capable of very-long-chain desaturation. The conserved desaturase architecture wherein a surface residue with a single bulky side chain forms the end of the substrate binding cavity predisposes them to single amino acid substitutions that enable a switch between long- and very-long-chain selectivity. The data presented here show that such changes have independently occurred multiple times during evolution.

Structure-Function of the High Affinity Substrate Binding Site (S1) of Human Norepinephrine Transporter

The human norepinephrine transporter (hNET) is a member of the neurotransmitter/sodium symporter family, which also includes the neuronal monoamine transporters for serotonin (SERT) and dopamine (DAT). Its involvement in chronic pain and many neurological disorders underlies its pharmaceutical importance. Using the X-ray crystal structures of the human serotonin transporter (hSERT) (PDB 5I6X) and Drosophila melanogaster dopamine transporter (dDAT) (PDB 4M48 and PDB 4XPA) as templates, we developed molecular models for norepinephrine (NE) bound to its high affinity binding site (S1) in the hNET. Our model suggests that the S1 site for NE is deeply buried between transmembrane helices (TMHs) 1, 3, 6, and 8 and overlaps the binding site for leucine in the bacterial leucine transporter (LeuT) and dopamine (DA) in dDAT. Mutational studies identified the functional binding pocket for NE comprised residues A73, A77, N78, V148, N153, I156, G320, F329, N350, S420, G423, and M424, which all influenced NE affinity and/or transport. These effects support a NE-hNET docking model where A73, A77, G320, S420, G423, and M424 form H-bond interactions with NE, V148, I156, and F329 form hydrophobic interactions with NE, whereas N78 affects NE transport and N350 affects NE affinity and transport via an influence on the octahedral co-ordination of the Na₁⁺ ion. Consistent with a conserved structure-function amongst sodium-dependent neurotransmitter transporters, S1 residues A73, A77 (G100 in hSERT), N78, V148 (I150 in hSERT), N153, G320, F329 (Y331 in d DAT), N350, and G423 are conserved in DAT and SERT, indicating they likely play conserved functional roles.

Policies of Exclusion: Implications for the Health of Immigrants and Their Children

Public policies play a crucial role in shaping how immigrants adapt to life in the United States. Federal, state, and local laws and administrative practices impact immigrants' access to education, health insurance and medical care, cash assistance, food assistance, and other vital services. Additionally, immigration enforcement activities have substantial effects on immigrants' health and participation in public programs, as well as effects on immigrants' families. This review summarizes the growing literature on the consequences of public policies for immigrants' health. Some policies are inclusive and promote immigrants' adaptation to the United States, whereas other policies are exclusionary and restrict immigrants' access to public programs as well as educational and economic opportunities. We explore the strategies that researchers have employed to tease out these effects, the methodological challenges of undertaking such studies, their varying impacts on immigrant health, and steps that can be undertaken to improve the health of immigrants and their families.

Two clusters of residues contribute to the activity and substrate specificity of Fm1, a bifunctional oleate and linoleate desaturase of fungal origin

Polyunsaturated fatty acids (PUFAs) have important industrial, physiological, and nutritional properties. Plants use the sequential activities of FAD2 and FAD3 desaturases to convert 18:1Δ9 to the important PUFA 18:3Δ9,12,15, whereas the fungus Fusarium verticillioides 7600 uses the bifunctional desaturase Fm1 for both reactions. Here, we used a combination of sequence comparisons, structural modeling, and mutagenesis experiments to investigate Fm1's regioselectivity and identified two functionally relevant clusters of residues that contribute to Fm1 activity. We found that cluster I (Leu¹⁵³, Phe¹⁵⁷, and His¹⁹⁴), located near the catalytic iron ions, predominantly affects activity, whereas cluster II (Tyr²⁸⁰, His²⁸⁴, and Leu²⁸⁷), located in a helix forming the entrance to the substrate-binding pocket, mainly specifies 15-desaturation. Individual or combined substitutions of cluster II residues substantially reduced 15-desaturation. The combination of F157W from cluster I with Y280L, H284V, and L287T from cluster II created an increased-activity variant that almost completely lost the ability to desaturate at C15 and acted almost exclusively as a 12-desaturase. No variants were identified in which 15-desaturation occurred in the absence of 12-desaturation. Fm1 displayed only traces of activity with C16 substrate, but several cluster I variants exhibited increased activity with both 18:1 and 16:1 substrates, converting 16:1Δ9 to 16:3Δ9,12,15, consistent with Fm1 performing sequential v + 3 desaturation reactions at C12 and then C15. We propose that cluster II residues interact with the substrate headgroup when the acyl chain contains both Δ9 and Δ12 double bonds, in which case C15 becomes positioned adjacent to the di-iron site enabling a second v + 3 desaturation.

Trace derivatives of kynurenine potently activate the aryl hydrocarbon receptor (AHR)

Cellular metabolites act as important signaling cues, but are subject to complex unknown chemistry. Kynurenine is a tryptophan metabolite that plays a crucial role in cancer and the immune system. Despite its atypical, non-ligand-like, highly polar structure, kynurenine activates the aryl hydrocarbon receptor (AHR), a PER, ARNT, SIM (PAS) family transcription factor that responds to diverse environmental and cellular ligands. The activity of kynurenine is increased 100-1000-fold by incubation or long-term storage and relies on the hydrophobic ligand-binding pocket of AHR, with identical structural signatures for AHR induction before and after activation. We purified trace-active derivatives of kynurenine and identified two novel, closely related condensation products, named trace-extended aromatic condensation products (TEACOPs), which are active at low picomolar levels. The synthesized compound for one of the predicted structures matched the purified compound in both chemical structure and AHR pharmacology. Our study provides evidence that kynurenine acts as an AHR pro-ligand, which requires novel chemical conversions to act as a receptor agonist.

Social and structural factors increase inconsistent condom use by sex workers' one-time and regular clients in Northern Uganda

While sex workers (SWs) bear the brunt of the epidemic in Uganda, there remains a dearth of empirical research on the structural drivers of HIV prevention among SWs. This study examined the drivers of inconsistent condom use by one-time and regular clients of young women SWs in Gulu, Northern Uganda. Data were drawn from the Gulu Sexual Health Study, a cross-sectional study of young SWs, aged 14 years and older (2011-2012). SWs were recruited using peer/SW-led outreach, in partnership with The AIDS Support Organization and other CBOs. Multivariable logistic regression was used to examine the correlates of inconsistent condom use by one-time and regular clients. In total, 84.5% of the 381 SWs servicing regular clients and 76.8% of the 393 SWs servicing one-time clients reported inconsistent client condom use. In multivariable analysis, physical/sexual violence by clients (AOR = 5.39; 95%CI 3.05-9.49), low sexual control by workers (measured by the validated Pulweritz scale) (AOR = 2.86; 95%CI 1.47-5.58), alcohol/drug use while working (AOR = 1.98; 95%CI 1.17-3.35) and migration to Gulu for sex work (AOR = 1.73; 95%CI 0.95-3.14) were positively correlated with inconsistent condom use by one-time clients. Correlates of inconsistent condom use by regular clients included: low sexual control by workers (AOR = 4.63; 95%CI 2.32-9.23); physical/sexual violence by clients (AOR = 3.48; 95%CI 1.85-6.53); police harassment (AOR = 2.57; 95%CI 1.17-5.65); and being a single mother (AOR = 2.07; 95%CI 1.09-3.93). Structural and interpersonal factors strongly influence inconsistent condom use by clients, with violence by clients and police, low sexual control by workers, migration and single-parenthood all linked to non-condom use. There is a need for peer-led structural interventions that improve access to occupational health and safety standards (e.g., violence prevention and alcohol/drug harm reduction policies/programming). Shifts away from the current punitive approaches towards SWs are integral to the success of such interventions, as they continue to undermine HIV prevention efforts.

Community mapping of sex work criminalization and violence: impacts on HIV treatment interruptions among marginalized women living with HIV in Vancouver, Canada

Despite the high HIV burden faced by sex workers, data on access and retention in antiretroviral therapy (ART) are limited. Using an innovative spatial epidemiological approach, we explored how the social geography of sex work criminalization and violence impacts HIV treatment interruptions among sex workers living with HIV in Vancouver over a 3.5-year period. Drawing upon data from a community-based cohort (AESHA, 2010-2013) and linked external administrative data on ART dispensation, GIS mapping and multivariable logistic regression with generalized estimating equations to prospectively examine the effects of spatial criminalization and violence near women's places of residence on 2-day ART interruptions. Analyses were restricted to 66 ART-exposed women who contributed 208 observations and 83 ART interruption events. In adjusted multivariable models, heightened density of displacement due to policing independently correlated with HIV treatment interruptions (AOR: 1.02, 95%CI: 1.00-1.04); density of legal restrictions (AOR: 1.30, 95%CI: 0.97-1.76) and a combined measure of criminalization/violence (AOR: 1.00, 95%CI: 1.00-1.01) were marginally correlated. The social geography of sex work criminalization may undermine access to essential medicines, including HIV treatment. Interventions to promote 'enabling environments' (e.g. peer-led models, safer living/working spaces) should be explored, alongside policy reforms to ensure uninterrupted treatment access.

Proximal disruption of base pairing of the second stem in the upper stem of pri-miR156a caused ambient temperature-sensitive flowering in Arabidopsis

MicroRNAs are generated from primary transcripts (pri-miRNAs) that form hairpin structures. Plant miRNAs play an important role in regulating flowering; however, little is known about the role of their structures in ambient temperature-responsive flowering. We recently showed that disruption of base pairing in the second stem (S2) in the upper stem of pri-miR156a caused hypersensitive flowering in response to ambient temperature changes. To further substantiate our findings on the role of S2 of pri-miR156a, we analyzed the effects of serial disruption (from the proximal or distal sides) of base-pairing in S2 of pri-miR156a on temperature-dependent flowering. We found that flowering time was gradually delayed with increasing size of the proximal disruption of S2 at 16°C. Particularly, disrupting base pairing of 5 nucleotides from the proximal side caused flowering to be hypersensitive to ambient temperature changes, which is similar to the phenotype of plants overexpressing pri-miR156a with a disruption of S2 (156-DBP-S2). However, disrupting base pairing from the distal side did not cause late flowering at 16°C and thus did not cause temperature-sensitive flowering. These results supported our notion that the second stem (S2) in the upper stem of pri-miR156a plays a role in the regulation of ambient temperature-responsive flowering.

The S1-S2 linker determines the distinct pH sensitivity between ZmK2.1 and KAT1

Efficient stomatal opening requires activation of KAT-type K(+) channels, which mediate K(+) influx into guard cells. Most KAT-type channels are functionally facilitated by extracellular acidification. However, despite sequence and structural homologies, the maize counterpart of Arabidopsis KAT1 (ZmK2.1) is resistant to pH activation. To understand the structural determinant that results in the differential pH activation of these counterparts, we analysed chimeric channels and channels with point mutations for ZmK2.1 and its closest Arabidopsis homologue KAT1. Exchange of the S1-S2 linkers altered the pH sensitivity between the two channels, suggesting that the S1-S2 linker is essentially involved in the pH sensitivity. The effects of D92 mutation within the linker motif together with substitution of the first half of the linker largely resemble the effects of substitution of the complete linker. Topological modelling predicts that one of the two cysteines located on the outer face section of the S5 domain may serve as a potential titratable group that interacts with the S1-S2 linker. The difference between ZmK2.1 and KAT1 is predicted to be the result of the distance of the stabilized linkers from the titratable group. In KAT1, residue K85 within the linker forms a hydrogen bond with C211 that enables the pH activation; conversely, the linker of ZmK2.1 is distantly located and thus does not interact with the equivalent titration group (C208). Thus, in addition to the known structural contributors to the proton activation of KAT channels, we have uncovered a previously unidentified component that is strongly involved in this complex proton activation network.

Preserving misconceptions or a call for action?--A hermeneutic re-reading of the Nativity story

Background

Behaviour is guided by perceptions and traditions. As such, understanding culture and religion is important in order to understand healthcare behaviour. Religious perceptions shape a person's understanding of the world and are maintained through texts and tradition. One such important religious text in relation to sexual and reproductive health is the Nativity story. This account of the conception and birth of Jesus is well known in the Christian cultural sphere and beyond, and it has for generations shaped perceptions of childbirth.

Methods

This paper attempts a re-reading of the Nativity story using a hermeneutic approach.

Results and Conclusion

This reveals a dual understanding of the Nativity, not just as an account of immaculate transcendence and a rosy Christmas tale, but as a source of identification for pregnant women and mothers and a call to action for improved maternal and child healthcare.

A systematic review of the clinical and social epidemiological research among sex workers in Uganda

BACKGROUND

In response to the high burden of disease among sex workers and their position as a population heavily affected by the HIV epidemic, there has been a growing body of literature investigating the prevalence and risk factors associated with HIV risk among sex workers. To contextualize and summarize the existing research evidence base, a systematic review was conducted to synthesize the epidemiological literature on sex workers in Uganda.

METHODS

Database selection and search strategy development followed the Cochrane Collaboration's standards for conducting systematic review searches. All studies that included sex workers as the primary research participants were included in the review. The search was then geographically restricted to the country of Uganda. Items were identified from 18 databases (grey and peer-review) on March 10-11, 2015.

RESULTS

A total of 484 articles were retrieved from the database search. After removal of duplicates, a total of 353 articles were screened for eligibility and 64 full-text articles were assessed. The final review included 24 studies with quantitative methodology conducted among sex workers in Uganda. The HIV prevalence among female sex workers ranged from 32.4-52.0 % and between 8.2-9.0 % had multiple HIV infections. Both multi-drug resistance to antiretroviral therapy (2.6 %) and antibiotics (83.1 %) were observed. Between 33.3-55.1 % reported inconsistent condom use in the past month. In the previous 6 months, over 80 % of sex workers experienced client-perpetrated violence and 18 % experienced intimate partner violence. Over 30 % had a history of extreme war-related trauma.

CONCLUSIONS

There was limited information on socio-structural factors that affect sex workers' commercial working environments in Uganda, including the role of policing and criminalization, as well as the prevalence and factors associated with violence. The majority of the existing evidence is based in Kampala, highlighting a need for information on sex work in other regions of Uganda. Additionally, there is limited information on features of the non-commercial components of sex workers' lives as well as the services needed to reduce risks outside of the sex industry.

Structure and agency in long-distance truck drivers' lived experiences of condom use for HIV prevention

Condom promotion has emerged as a mainstay of targeted HIV prevention interventions in India, with its emphasis on individual behaviour change and personal responsibility. However, such approaches often do not account for marginalised populations' structural vulnerability to HIV, arising from social, economic and political factors in the lived environment. In this paper, I use a critical health communication framework to analyse how structure and agency interact in influencing condom use among long-distance truck drivers in India. Drawing on an abductive discourse analysis of condom-use discourses among truckers and peer educators in two Indian cities, findings reveal that while truckers understand the biomedical logic of condoms as barriers, they also express anxiety about condom breakage and experience structural barriers to condom use. The paper concludes by calling for greater attention to structural vulnerabilities in future HIV prevention efforts with truck drivers.

Low prospects and high risk: structural determinants of health associated with sexual risk among young African American women residing in resource-poor communities in the south

African American women at increased risk of HIV/sexually transmitted infection (STI) may engage in risky sex as a coping mechanism for depressed economic conditions. This study examines the association between high-risk sexual behavior and structural determinants of sexual health among a sample of young African American women. 237 young African American women (16-19 years old) from economically disadvantaged neighborhoods in North Carolina were enrolled into a randomized trial testing the efficacy of an adapted HIV/STI prevention intervention. Logistic regression analyses predicted the likelihood that young women reporting lack of food at home, homelessness and low future prospects would also report sexual risk behaviors. Young women reporting a lack of food at home (22 %), homelessness (27 %), and low perceived education/employment prospects (19 %) had between 2.2 and 4.7 times the odds as those not reporting these risk factors of reporting multiple sex partners, risky sex partners including older men and partners involved in gangs, substance use prior to sex, and exchange sex. Self-reported structural determinants of sexual health were associated with myriad sexual risk behaviors. Diminished economic conditions among these young women may lead to sexual risk due to hopelessness, the need for survival or other factors.

Structural determinants of protein folding

The last several decades have seen an explosion of knowledge in the field of structural biology. With critical advances in spectroscopic techniques in examining structures of biomacromolecules, in maturation of molecular biology techniques, as well as vast improvements in computation prowess, protein structures are now being elucidated at an unprecedented rate. In spite of all the recent advances, the protein folding puzzle remains as one of the fundamental biochemical challenges. A facet to this empiric problem is the structural determinants of protein folding. What are the driving forces that pivot a polypeptide chain to a specific conformation amongst the vast conformation space? In this review, we shall discuss some of the structural determinants to protein folding that have been identified in the recent decades.