Randomized Clinical Trial of Stigma Counseling and HIV Testing Access Interventions to Increase HIV Testing Among Black Sexual Minority Men and Transwomen

Advances in HIV prevention tools have outpaced our ability to ensure equitable access to these tools. Novel approaches to reducing known barriers to accessing HIV prevention, such as stigma and logistical-related factors, are urgently needed. To evaluate the efficacy of a randomized controlled trial with four intervention arms to address barriers to HIV/STI testing uptake (primary outcome) and PrEP use, depression, and HIV test results (secondary outcomes). We tested a 2 × 2 research design: main effect 1-stigma-focused vs. health information evaluation-focused counseling, main effect 2-offering HIV/STI testing appointments in person vs. at home with a counselor via video chat, and the interaction of the main effects. Participants (N = 474) residing in the southeastern USA were screened and enrolled in a longitudinal trial. Intervention efficacy was established using generalized linear modeling with binomial or Poisson distributions. Intervention efficacy demonstrated an increase in HIV/STI testing uptake when testing was made available at home with a counselor via video chat vs. in person (83% vs. 75% uptake, p < .05), and participants were also more likely to test positive for HIV over the course of the study in the at-home condition (14.5% vs. 9.4%, p < .05). Stigma-focused counseling resulted in lower depression scores and greater uptake of PrEP among participants < 30 years of age when compared with health information counseling (15.4% vs. 9.6%, p < .05). In order to prevent further disparities between HIV prevention advances and access to HIV prevention tools, we must prioritize improvements in linking people to care. Novel interventions, such as those proposed here, offer a practical, evidence-based path to addressing long-standing barriers to HIV prevention strategies. Trial registration: NCT03107910.

Novel Latent Profile Analysis of a Test of Concept, Stigma Intervention to Increase PrEP Uptake Among Black Sexual Minority Men

BACKGROUND

Pre-exposure prophylaxis (PrEP) has demonstrated efficacy for HIV prevention, yet uptake of PrEP among populations in urgent need of prevention tools (eg, Black sexual minority men) is limited, and stigma and medical mistrust remain strong barriers to accessing PrEP.

PURPOSE

To evaluate a test of concept brief intervention to address stigma and medical mistrust as barriers to PrEP uptake using novel latent profile analysis.

METHODS

Participants (N = 177) residing in the southeastern US were randomized to 1 of 4 arms to establish the potential impact of a brief, stigma focused counseling intervention (referred to as Jumpstart ) to increase PrEP uptake. We estimated intervention effect size (Cramer's V) for PrEP uptake and then explored differential intervention effects across latent profiles of psychosocial barriers to PrEP use.

RESULTS

The intervention resulted in small, but meaningful effect size, with self-reported PrEP uptake increasing across Jumpstart conditions with the control condition reporting 24% uptake and Jumpstart plus text/phone calls (the most intensive intervention arm) reporting 37% uptake, and a similar pattern emerging for biologically confirmed PrEP use. Among participants 30 and older, Jumpstart participants were more likely to move to a postintervention profile with fewer barriers than control participants and reported the highest uptake of PrEP.

CONCLUSIONS

Addressing social/emotional barriers to PrEP uptake is an essential component of bridging the gap between advances being made in biomedical forms of HIV prevention, and establishing and supporting access to those advances.

Associations of past-year stigma and psychosocial syndemic conditions: Considerations for intersectional stigma measures among Black Sexual Minority Men

This secondary analysis of a mixed serostatus sample of Black sexual minority men (BSMM) used conditional inference tree methods to explore associations of past-year experienced stigma and psychosocial syndemic conditions. Experienced stigmas were attributed to race, sexuality, socioeconomic status, HIV status or some "other" reason. Psychosocial syndemic conditions studied included physical assault, intimate partner violence, polysubstance use, and depression symptomology. Data are from Promoting Our Worth, Equality and Resilience (POWER), a serial, cross-sectional study conducted between 2014-2017 (N=4430). Experiences of multiple stigmas were reported by n=938 (22.1%) of BSMM. Conditional inference tree results revealed that HIV-related stigma and its intersection with "other" stigma showed the greatest variance in psychosocial condition prevalence. Our findings suggest that when developing intercategorical intersectional analyses with BSMM, there are important stigmas for BSMM beyond those attributed to race, sexuality, and SES, particularly intersecting with HIV-related stigma. Conditional inference tree analysis shows promise in quantitative explorations of intersectional stigma with BSMM, but will benefit from the inclusion of additional forms of stigma, which should be considered by the field moving forward.

PrEP-Related Interactive Toxicity Beliefs: Associations With Stigma, Substance Use, and PrEP Uptake

Despite documented efficacy in reducing HIV transmission, pre-exposure prophylaxis (PrEP) uptake among Black sexual minority men (BSMM) is limited. One understudied factor which may impede PrEP uptake is PrEP-related interactive toxicity beliefs (i.e., believing it is hazardous to use alcohol/drugs while taking PrEP). Data from N = 169 HIV negative BSMM over 4 months showed high rates of agreement with at least one alcohol (78%) or drug (84%) interactive toxicity belief. Univariate analyses showed increased alcohol or drug interactive toxicity beliefs predicted lower PrEP uptake. Multivariable regression suggested those with PrEP-related alcohol or drug interactive toxicity beliefs were more likely to report high PrEP stigma, more negative PrEP beliefs (e.g., concern that taking PrEP disrupts life), and were more likely to use alcohol/drugs (respectively) prior to/during sex. Findings warrant intervention work targeting interactive toxicity beliefs with tailored messaging to mitigate PrEP stigma and correct concerns around substance use and PrEP.

Intersectional Experienced Stigma and Psychosocial Syndemic Conditions in a Sample of Black Men Who Have Sex with Men Engaged in Sex Work (BMSM-SW) from Six US Cities

Black men who have sex with men (BMSM) in the United States experience a disproportionate burden of violence, substance use, physical and mental health conditions relative to other racial groups. BMSM who engage in sex work (BMSM-SW) experience a high burden of psychosocial conditions, sexually transmitted infections, including HIV, and intersectional stigma. This analysis characterizes remuneration and client typologies for BMSM-SW, documents intersectional stigma experienced by BMSM-SW relative to other BMSM, and explores the impact of experienced intersectional stigma on the relationship between sex work engagement and psychosocial syndemic conditions (violence, polydrug use, and depression symptoms). Results show that a majority of BMSM-SW in the sample had female clients and that sex workers were more likely than other BMSM to hire another sex worker. BMSM-SW were more likely than other BMSM to report stigma attributed to race; sexuality; HIV status; socioeconomic status; and "other" attributes, and were more likely to report experiencing stigma across all settings assessed (schools; healthcare; employment; housing; police/courts; and in public/community). Intersectional stigma mediated the relationship between sex work engagement and psychosocial syndemic conditions, accounting for 49% (95% CI: 47.6-50.0%) of the relationship. Interventions for BMSM-SW should include resilience-building components to counteract the effects of intersectional stigma.

Characterizing Biomedical HIV Prevention Awareness and Use Among Black Transgender Women in the United States

Black transgender women (BTW) in the United States experience disproportionate rates of HIV despite biomedical prevention interventions such as pre-exposure prophylaxis (PrEP) and non-occupational post-exposure prophylaxis (nPEP). Using a sample of 490 BTW collected from 2014 to 2017, bivariate, multivariable, and multinomial analyses were conducted to determine factors associated with awareness and use of PrEP and nPEP. BTW living with HIV were more aware of PrEP than HIV-negative BTW. Structural, demographic, and trans-specific factors (e.g., experiences of homelessness, violence, and current hormone use) related to HIV risk were associated with PrEP and nPEP awareness. PrEP use was associated with behavioral HIV risks (e.g., STI diagnosis, having an HIV-positive partner, and needle-sharing) and may demonstrate risk recognition among BTW. Knowing someone using PrEP was significantly positively associated with PrEP use. Development of guidelines for PrEP and nPEP use for BTW should leverage the strengths of guidelines for other populations, while also acknowledging the unique risks for this population.

Methods for Authenticating Participants in Fully Web-Based Mobile App Trials from the iReach Project: Cross-sectional Study

Background

Mobile health apps are important interventions that increase the scale and reach of prevention services, including HIV testing and prevention counseling, pre-exposure prophylaxis, condom distribution, and education, of which all are required to decrease HIV incidence rates. The use of these web-based apps as well as fully web-based intervention trials can be challenged by the need to remove fraudulent or duplicate entries and authenticate unique trial participants before randomization to protect the integrity of the sample and trial results. It is critical to ensure that the data collected through this modality are valid and reliable.

Objective

The aim of this study is to discuss the electronic and manual authentication strategies for the iReach randomized controlled trial that were used to monitor and prevent fraudulent enrollment.

Methods

iReach is a randomized controlled trial that focused on same-sex attracted, cisgender males (people assigned male at birth who identify as men) aged 13-18 years in the United States and on enrolling people of color and those in rural communities. The data were evaluated by identifying possible duplications in enrollment, identifying potentially fraudulent or ineligible participants through inconsistencies in the data collected at screening and survey data, and reviewing baseline completion times to avoid enrolling bots and those who did not complete the baseline questionnaire. Electronic systems flagged questionable enrollment. Additional manual reviews included the verification of age, IP addresses, email addresses, social media accounts, and completion times for surveys.

Results

The electronic and manual strategies, including the integration of social media profiles, resulted in the identification and prevention of 624 cases of potential fraudulent, duplicative, or ineligible enrollment. A total of 79% (493/624) of the potentially fraudulent or ineligible cases were identified through electronic strategies, thereby reducing the burden of manual authentication for most cases. A case study with a scenario, resolution, and authentication strategy response was included.

Conclusions

As web-based trials are becoming more common, methods for handling suspicious enrollments that compromise data quality have become increasingly important for inclusion in protocols.

International Registered Report Identifier (IRRID)

RR2-10.2196/10174

Syndemic Health Disparities and Sexually Transmitted Infection Burden Among Black Men Who Have Sex with Men Engaged in Sex Work in the U.S

Black men who have sex with men (MSM) engaged in sex work (BMSM-SW) experience elevated HIV and sexually transmitted infection (STI) prevalence. Further, BMSM-SW have been shown to have higher rates of syndemic psychosocial health conditions which contribute to HIV risk behavior and incidence, and poorer care outcomes than other groups of men who have sex with men. However, syndemic perspectives have not been applied to understanding past-year STI burden among BMSM-SW in the U.S. Sexually active Black MSM ≥ 18 years old were recruited from Black Pride events in six U.S. cities (n = 4421) between 2014 and 2017. Multivariable logistic regressions assessed correlates of past-year sex work engagement; whether BMSM-SW had higher odds of syndemic conditions; and whether BMSM-SW had higher odds of self-reported, past-year STI diagnoses. Structural equation models assessed relationships between sex work engagement, syndemic conditions, and STI controlled for sociodemographics and number of sexual partners. A total of 254 (5.7%) Black MSM reported past-year sex work, of whom 45.3% were HIV positive. BMSM-SW were significantly more likely to be Hispanic, to report past-year bisexual behavior, and to report annual income < $10,000. In multivariable models, BMSM-SW were significantly more likely to report intimate partner violence, assault victimization, polydrug use, and depression symptoms; they were also more likely to report past-year gonorrhea, chlamydia, and syphilis. Syndemic conditions mediated the relationship between past-year sex work and past-year STI burden, constituting a significant indirect effect. BMSM-SW in the U.S. face severe biopsychosocial health disparities. Interventions developed for BMSM engaged in sex work are lacking. Our results suggest that interventions containing safer sex work education and sex-positive biobehavioral HIV/STI prevention alongside substance use, mental health, employment, and education components will be most effective.

Barriers and facilitators to past six-month HIV testing among men who have sex with men in Belize

Prevalence of HIV in Belize is high, and men who have sex with men (MSM) are disproportionately impacted by HIV. HIV testing is critical in curbing the epidemic; however, little is known about factors associated with testing among MSM in Belize. Working with a non-governmental organization in a large, urban city within Belize, snowball sampling was applied to recruit Belizean MSM to complete a self-administered survey. Multivariable logistic regression analysis was employed to understand associations with HIV screening behavior. Access to healthcare, HIV knowledge, and reporting having heard of Section 53 of the Criminal Code of Belize (once outlawing same-sex sexual behavior), but not experiencing any negative impact from Section 53 were significantly positively associated with having received an HIV test in the past six months. Healthcare maltreatment (lifetime), depression symptomology, and shame were significantly negatively associated with having received a HIV test in the past six months. Findings suggest that multiple factors associated with stigma and discrimination negatively affect testing strategies among MSM in Belize.

Black Men Who Have Sex with Men and Lifetime HIV Testing: Characterizing the Reasons and Consequences of Having Never Tested for HIV

HIV testing remains a critical point of entry to HIV treatment services and now biomedical prevention as well. Yet despite the high HIV prevalence among Black men who have sex with men (MSM), insufficient attention has been given to factors associated with those Black MSM in the United States who have never received an HIV test in their lifetime. Promoting Our Worth, Equality, & Resilience (POWER) is a cross-sectional observational study that recruited Black MSM at Black Pride events across six cities in the United States from 2014 to 2017. Participants completed an anonymous questionnaire and were offered free, confidential HIV testing. Of the 4174 Black MSM without a prior HIV diagnosis, 404 (9.68%) had never tested for HIV (mean age = 31.03 years). Lower education and greater internalized homophobia were associated with never having tested for HIV. Higher age (AOR = 1.05, 95%, 1.02-1.07) and assumption of HIV-positivity (AOR = 3.24, 95% CI 1.53-6.84) were both associated with increased odds of an HIV-positive test result (n = 119; 36%). To compare, HIV prevalence among Black MSM who had received at least one HIV test before study participation was 23%. While a minority of Black MSM had never received an HIV test, this group had a significantly higher likelihood of HIV infection. Alternative HIV testing strategies are needed to facilitate HIV testing initiation among Black MSM for whom conventional HIV testing modalities are insufficient.

National trends in HIV pre-exposure prophylaxis awareness, willingness and use among United States men who have sex with men recruited online, 2013 through 2017

INTRODUCTION

Pre-exposure prophylaxis (PrEP) is a key HIV prevention technology, and is a pillar of a comprehensive HIV prevention approach for men who have sex with men (MSM). Because there have been no national data to characterize trends in the PrEP continuum in the United States, overall and for key demographic groups of MSM, we aimed to describe the extent to which PrEP awareness, willingness and use changed over time, overall and for specific groups of MSM critical for HIV prevention (e.g. Black and Hispanic MSM, younger MSM, MSM in rural areas and MSM without health coverage).

METHODS

The American Men's Internet Survey (AMIS) is an annual survey of US MSM conducted in the United States among MSM aged ≥15 years since 2013. We analysed data on trends in elements of the PrEP continuum (awareness, willingness and use of PrEP) in a sample of 37,476 HIV-negative/unknown status MSM from December 2013 through November 2017. We evaluated trends in continuum steps overall and among demographic subgroups using Poisson models with Generalized Estimating Equations. For 2017 data, we used logistic regression to compare the prevalence of PrEP use among demographic groups.

RESULTS

Overall, 51.4% (n = 19,244) of AMIS respondents were PrEP-eligible across study years. Between 2013 and 2017, PrEP awareness increased from 47.4% to 80.6% willingness to use PrEP increased from 43.9% to 59.5% and PrEP use in the past 12 months increased from 1.7% to 19.9%. In 2017, use of PrEP was lower for men who were younger, lived outside of urban areas, and lacked health insurance; PrEP use was not different among Black, Hispanic and white MSM.

CONCLUSIONS

Our data show progress in use of PrEP among US MSM, but also reveal mismatches between PrEP use and epidemic need. We call for additional support of PrEP initiation, especially among young, non-urban and uninsured MSM. Black and Hispanic MSM report levels of PrEP use no different from white MSM, but given higher HIV incidence for Black and Hispanic MSM, parity in use is not sufficient for epidemic control or health equity.

Examining the Impact of a Psychosocial Syndemic on Past Six-Month HIV Screening Behavior of Black Men who have Sex with Men in the United States: Results from the POWER Study

Syndemic production theory has been used to explore HIV transmission risk or infections but has not been used to investigate prevention behavior, or with large samples of non-Whites. This analysis is the first to explore the impact of syndemic factors on previous six-month HIV screening behavior among US Black MSM. Data from Promoting Our Worth, Equality and Resilience (POWER) were analyzed from 3294 participants using syndemic variable counts and measures of interaction/synergy. Syndemic variables included: past three-month poly-drug use, depression, last year intimate partner violence, HIV risk and problematic binge drinking. BMSM reporting two syndemic factors were more likely to report screening (AOR = 1.37, 95% CI 1.04-1.80; p = 0.028) with no significant associations for three or more conditions. Measures of joint effect revealed that there were synergies among depression, problematic binge drinking and poly-drug use but these psychosocial factors cannot entirely explain testing patterns and excess disease burden among BMSM.

HIV Prevention Via Mobile Messaging for Men Who Have Sex With Men (M-Cubed): Protocol for a Randomized Controlled Trial

Background

Men who have sex with men (MSM) continue to be the predominately impacted risk group in the United States HIV epidemic and are a priority group for risk reduction in national strategic goals for HIV prevention. Modeling studies have demonstrated that a comprehensive package of status-tailored HIV prevention and care interventions have the potential to substantially reduce new infections among MSM. However, uptake of basic prevention services, including HIV testing, sexually transmitted infection (STI) testing, condom distribution, condom-compatible lubricant distribution, and preexposure prophylaxis (PrEP), is suboptimal. Further, stronger public health strategies are needed to promote engagement in HIV care and viral load suppression among MSM living with HIV. Mobile health (mHealth) tools can help inform and encourage MSM regarding HIV prevention, care, and treatment, especially among men who lack access to conventional medical services. This protocol details the design and procedures of a randomized controlled trial (RCT) of a novel mHealth intervention that comprises a comprehensive HIV prevention app and brief, tailored text- and video-based messages that are systematically presented to participants based on the participants’ HIV status and level of HIV acquisition risk.

Objective

The objective of the RCT was to test the efficacy of the Mobile Messaging for Men (M-Cubed, or M3) app among at least 1200 MSM in Atlanta, Detroit, and New York. The goal was to determine its ability to increase HIV testing (HIV-negative men), STI testing (all men), condom use for anal sex (all men), evaluation for PrEP eligibility, uptake of PrEP (higher risk HIV-negative men), engagement in HIV care (men living with HIV), and uptake of and adherence to antiretroviral medications (men living with HIV). A unique benefit of this approach is the HIV serostatus-inclusiveness of the intervention, which includes both HIV-negative and HIV-positive MSM.

Methods

MSM were recruited through online and venue-based approaches in Atlanta, Detroit, and New York City. Men who were eligible and consented were randomized to the intervention (immediate access to the M3 app for a period of three months) or to the waitlist-control (delayed access) group. Outcomes were evaluated immediately postintervention or control period, and again three and six months after the intervention period. Main outcomes will be reported as period prevalence ratios or hazards, depending on the outcome. Where appropriate, serostatus/risk-specific outcomes will be evaluated in relevant subgroups. Men randomized to the control condition were offered the opportunity to use (and evaluate) the M3 app for a three-month period after the final RCT outcome assessment.

Results

M3 enrollment began in January 2018 and concluded in November 2018. A total of 1229 MSM were enrolled. Data collection was completed in September 2019.

Conclusions

This RCT of the M3 mobile app seeks to determine the effects of an HIV serostatus–inclusive intervention on the use of multiple HIV prevention and care-related outcomes among MSM. A strength of the design is that it incorporates a large sample and broad range of MSM with differing prevention needs in three cities with high prevalence of HIV among MSM.

Trial Registration

ClinicalTrials.gov NCT03666247; https://clinicaltrials.gov/ct2/show/NCT03666247

International Registered Report Identifier (IRRID)

DERR1-10.2196/16439

Intimate Partner Violence and Depression among Black Transgender Women in the USA: The Potential Suppressive Effect of Perceived Social Support

Depression among Black transgender women (BTW) in the USA is an often understudied mental health concern with far-reaching consequences for overall physical and mental health at both the individual and community levels. Intimate partner violence (IPV) among BTW is also a frequently understudied and important social determinant of health in need of further exploration. This study sought to address the gap in research on the relationship between IPV and depression among BTW using a time- and location-based community sample of BTW from six US cities. In addition, it sought to explore the potential protective or suppressive effect of perceived social support on this relationship. Generalized structural equation models were used to assess conditional direct and indirect effects of IPV on depression via the suppression effect of perceived social support. Evidence was found of a statistically significant conditional direct effect of IPV on depression as well as a statistically significant suppression effect for perceived social support. Specifically, there was a 20% lower likelihood of increased depressive symptomatology for every 1-unit increase in perceived social support reported by participants. These findings indicated that perceived social support may be an important intervention point for helping to improve the mental health and well-being of BTW.

Prevalence and Correlates of PrEP Awareness and Use Among Black Men Who Have Sex with Men and Women (MSMW) in the United States

Men who have sex with men and women (MSMW), including those who are Black, experience HIV-related disparities compared to men who have sex with men only (MSMO). Few studies have assessed the prevalence and correlates of pre-exposure prophylaxis (PrEP) awareness and use among Black MSMW. We recruited MSM ≥ 18 attending Black Gay Pride events between 2014-2017. We conducted multivariable logistic regressions to assess differences in PrEP awareness and use among HIV-negative Black MSM (n = 2398) and within Black MSMW (n = 419). MSMW were less likely than MSMO to report PrEP awareness (p < 0.001). Among PrEP-aware MSM, MSMW were more likely than MSMO to report PrEP use (p < 0.05). MSMW receiving gay community support were more likely to be PrEP-aware (p < 0.01). MSMW reporting any past-year STI diagnoses were more likely to report PrEP use (p < 0.01). Findings suggest that PrEP awareness campaigns tailored for Black MSMW, concomitant with STI-to-PrEP interventions, will facilitate greater PrEP uptake in this population.

Understanding the impact of a syndemic on the use of pre-exposure prophylaxis in a community-based sample of behaviorally PrEP-eligible BMSM in the United States

HIV Pre-Exposure Prophylaxis (PrEP) has shown great promise in reducing HIV transmission among affected populations; however, PrEP uptake among Black men who have sex with men (BMSM) has stalled. This study compares BMSM using PrEP and BMSM at risk for HIV not using PrEP based on differences in behavior, psychosocial conditions and the presence of a syndemic (n = 1,411). BMSM reporting PrEP use were significantly more likely to report three of five HIV risk behaviors and three of four psychosocial conditions. Odds of reporting PrEP use increased as the number of psychosocial conditions increased such that BMSM with three psychosocial conditions (AOR = 5.65, 95% CI: 3.17, 10.08) and four conditions (AOR = 18.34, 95% CI: 5.01, 67.20) demonstrated significantly greater odds of PrEP use compared to BMSM reporting one or less conditions. While BMSM at greatest risk are using PrEP, strategies are still needed for men at varying risk levels.

Characterizing the HIV care continuum among a community sample of black men who have sex with men in the United States

Black men who have sex with men (BMSM) have the highest HIV incidence rates among all men who have sex with men (MSM) and have been less likely than other MSM to be diagnosed, linked or retained in care for HIV. The Promoting Our Worth, Equality, and Resilience (POWER) study administered a behavioral health survey and HIV test to BMSM to estimate the HIV continuum of care among a community-derived sample. Of the N = 1,680 BMSM living with HIV, n = 956 (56.9%) were aware of their HIV-positive status. BMSM who had been previously diagnosed reported progression through the care continuum at greater than 80% for linkage to medical care (97.6%), retention in medical care (97.3%), prescription of antiretroviral therapy (93.6%) and viral suppression (86.4%). Results of this analysis reveal the urgent need to ensure BMSM are being screened and diagnosed. Additionally, community-driven samples are a promising method offering the opportunity to build on the resilience of BMSM progressing though the continuum as well as engage BMSM not yet in care. Lastly, such methods can assist in communicating with those lost to retention.

Elevated HIV Prevalence and Correlates of PrEP Use Among a Community Sample of Black Men Who Have Sex With Men

BACKGROUND

The HIV epidemic among black men who have sex with men (BMSM) demands urgent public health attention. Pre-exposure prophylaxis (PrEP) is a highly efficacious option for preventing HIV, but characteristics of PrEP use among community samples of BMSM are not well-understood.

METHODS

A serial cross-sectional survey assessment (N = 4184 BMSM reporting HIV-negative/unsure status) and HIV testing were conducted at Black Gay Pride events in 6 US cities in 2014, 2015, 2016, and 2017.

RESULTS

HIV prevalence was higher among BMSM self-reporting current PrEP use (1 of 3 participants) than BMSM not self-reporting current PrEP use (1 of 5 participants) [32.3%, N = 103/319 vs. 20.0%, N = 639/3,193, adjusted odds ratio (aOR) = 1.68, 95% confidence interval (CI): 1.31 to 2.15]. BMSM reporting current PrEP use (N = 380) were more likely to report having a greater number of male sex partners (aOR = 1.02, 95% CI: 1.01 to 1.03), a sexually transmitted infection diagnosis (aOR = 2.44, 95% CI: 1.88 to 3.16), and stimulant drug use (aOR = 2.05, 95% CI, 1.21 to 3.47) when compared with BMSM not reporting current PrEP use (N = 3804). PrEP use increased from 4.7% (2014) to 15.5% (2017) (aOR = 1.19, 95% CI: 1.13 to 1.25). Among PrEP users, inability to afford health care coverage was associated with testing HIV-positive (aOR = 2.10, 95% CI: 1.24 to 3.56).

CONCLUSIONS

The high prevalence of HIV infection among BMSM reporting PrEP use is concerning. It does not, however, challenge the efficacy of PrEP itself but rather the uptake of the surrounding preventative package including behavioral risk reduction support, sexually transmitted infection treatment, and medication adherence counseling. Further research to understand barriers to fully effective PrEP is needed to guide operational and behavioral interventions that close the gap on incident infection.

For Better or for Worse? A Systematic Review of the Evidence on Social Media Use and Depression Among Lesbian, Gay, and Bisexual Minorities

BACKGROUND

Over 90% of adults in the United States have at least one social media account, and lesbian, gay, and bisexual (LGB) persons are more socially active on social media than heterosexuals. Rates of depression among LGB persons are between 1.5- and 2-fold higher than those among their heterosexual counterparts. Social media allows users to connect, interact, and express ideas, emotions, feelings, and thoughts. Thus, social media use might represent both a protective and a risk factor for depression among LGB persons. Studying the nature of the relationship between social media use and depression among LGB individuals is a necessary step to inform public health interventions for this population.

OBJECTIVE

The objective of this systematic review was to synthesize and critique the evidence on social media use and depression among LGB populations.

METHODS

We conducted a literature search for quantitative and qualitative studies published between January 2003 and June 2017 using 3 electronic databases. Articles were included if they were peer-reviewed, were in English, assessed social media use either quantitatively or qualitatively, measured depression, and focused on LGB populations. A minimum of two authors independently extracted data from each study using an a priori developed abstraction form. We assessed appropriate reporting of studies using the Strengthening the Reporting of Observational Studies in Epidemiology and the Consolidated Criteria for Reporting Qualitative Research for quantitative and qualitative studies, respectively.

RESULTS

We included 11 articles in the review; 9 studies were quantitative and cross-sectional and 2 were qualitative. Appropriate reporting of results varied greatly. Across quantitative studies, we found heterogeneity in how social media use was defined and measured. Cyberbullying was the most studied social media experience and was associated with depression and suicidality. Qualitative studies found that while social media provides a space to disclose minority experiences and share ways to cope and get support, constant surveillance of one's social media profile can become a stressor, potentially leading to depression. In most studies, sexual minority participants were identified inconsistently.

CONCLUSIONS

This review supports the need for research on the role of social media use on depression outcomes among LBG persons. Using social media may be both a protective and a risk factor for depression among LGB individuals. Support gained via social media may buffer the impact of geographic isolation and loneliness. Negative experiences such as cyberbullying and other patterns of use may be associated with depression. Future research would benefit from more consistent definitions of both social media use and study populations. Moreover, use of larger samples and accounting for patterns of use and individuals' experiences on social media may help better understand the factors that impact LGB mental health disparities.

Methemoglobinemia and eccentrocytosis in equine erythrocyte flavin adenine dinucleotide deficiency

This report describes erythrocyte biochemical findings in an adult Spanish mustang mare that exhibited persistent methemoglobinemia, eccentrocytosis, and pyknocytosis that were not related to the consumption or administration of an exogenous oxidant. The methemoglobinemia was attributed to a deficiency in cytochrome-b5 reductase (Cb5R) activity, and the eccentrocytes and pyknocytes were attributed to a marked deficiency in reduced nicotinamide adenine dinucleotide phosphate-dependent glutathione reductase (GR) activity that resulted in decreased reduced glutathione concentration within erythrocytes. The GR activity increased to a near-normal value after addition of flavin adenine dinucleotide (FAD) to the enzyme assay, indicating a deficiency of FAD in erythrocytes. The methemoglobinemia, eccentrocytosis, and pyknocytosis were attributed to deficiency of FAD in erythrocytes because the GR and Cb5R enzymes use FAD as a cofactor. This deficiency in FAD results from a defect in erythrocyte riboflavin metabolism, which has not been documented previously in animals.

Influence of sex and female hormones on nicotine-induced changes in locomotor activity in rats

The acute and chronic effects of nicotine (0.4 mg/kg s.c.) on locomotor activity in photocell cages have been compared in male, female, and ovariectomized hooded rats. In Experiment 1, female rats displayed higher locomotion than males (n = 12); acutely, nicotine-reduced locomotion, and this effect was slightly larger in females than males. Daily administration of nicotine for 21 days produced a similar, gradual increase in activity in both sexes. Tests then confirmed greater activity in females than males and as a function of previous chronic exposure to nicotine (n = 6); there was an activating effect of nicotine challenge but no interaction of nicotine effects with sex. In Experiment 2, ovariectomized rats were primed with 17-beta-estradiol (50 microg/kg s.c.) and progesterone (2.5 mg/kg s.c.) or vehicle only. Acute administration of nicotine reduced activity in both groups similarly (n = 12). After nicotine daily for 21 days, there was increased activity as a function of both chronic nicotine and hormonal priming, and challenge with nicotine increased activity (n = 6). The effects of these challenges with nicotine were also slightly greater, as a function of previous nicotine exposure and priming. As a whole, these experiments showed robust effects of acute and chronic nicotine administration, sex, and hormonal priming; neither sex nor gonadal hormones had marked influences on changes in locomotor activity produced by nicotine.

Membrane and tissue distribution of folate binding protein in pig

Folate binding protein may participate in folate homeostasis by regulating monoglutamyl folate transport across relevant cell membranes. We compared the activity, immunoreactivity, and transcripts of folate binding protein in pig liver, kidney, and jejunal mucosa and their relevant cell membranes. Binding of [3H]folic acid was sixfold greater to pig liver plasma membranes than to kidney brush-border membranes, whereas there was no binding to jejunal brush-border membranes. The IgG fraction of rabbit antibody detected pig recombinant folate binding protein at 30 kDa and stained pig liver plasma membranes and kidney brush-border membranes but did not react with jejunal brush-border membranes. Folate binding protein transcripts were present in threefold greater abundance in pig liver than in kidney. Species comparisons showed folate binding protein transcripts in rat and human kidney but not in liver. Thus folate binding protein participates in folate homeostasis by regulating uptake by renal tubular membranes and uniquely by pig liver plasma membranes, but it is not involved in jejunal folate absorption.

Selective antagonism of behavioural effects of nicotine by dihydro-beta-erythroidine in rats

The influence of the nicotine antagonist dihydro-beta-erythroidine (DH beta E) was examined on various behavioural effects of nicotine in rats. Motor activity was recorded in photocell cages whereas discriminative stimulus effects were examined using two-lever drug discrimination procedures with a tandem schedule of food reinforcement (n = 8 throughout). DH beta E (0.1-3.2 mg/kg) failed to antagonise the decreases in motor activity that nicotine (0.4-0.6 mg/kg) produced in experimentally naive rats, whereas mecamylamine (1.5 mg/kg) completely blocked this effect of nicotine. DH beta E (0.1-3.2 mg/kg) antagonised the increases in motor activity that nicotine (0.4 mg/kg) produced in rats with extensive previous exposure to both nicotine and the photocell apparatus. In rats trained to discriminate either 0.1 or 0.4 mg/kg nicotine from saline, DH beta E (0.1-3.2 mg/kg) blocked the discriminative stimulus effect of nicotine. The block of the discriminative effect could be reversed by increasing the dose of nicotine; DH beta E (1.6 mg/kg) shifted the dose-response curve for nicotine discrimination to the right by a factor of 9.4. In addition, nicotine in doses of 0.32-0.64 mg/kg decreased the overall rate of lever pressing but DH beta E (1.6 mg/kg) did not influence the dose-response curve for this effect. Thus, DH beta E potently blocked the locomotor activating and discriminative stimulus effects of nicotine at doses that did not antagonise its locomotor depressant and operant response rate-reducing effects. This selective blockade supports the involvement of different subtypes of nicotinic receptor in the mediation of diverse behavioural effects. Furthermore, the rightward shift of the dose-response curve for nicotine discrimination suggested a competitive mode of action for DH beta E.

Discriminative stimulus properties of the nicotinic agonist cytisine

Cytisine binds with high affinity and specificity to neuronal nicotinic receptors but its physiological and behavioural effects are complex and differ from those of nicotine. The present study explores the behavioural aspects further by comparing the discriminative stimulus effects of cystisine with those of nicotine. Two groups of rats were trained to discriminate cytisine (2 mg/kg s.c.) or nicotine (0.2 mg/kg s.c.) from saline in a two-lever operant conditioning procedure with food reinforcers presented on a tandem VI FR schedule. A third group of rats was trained to discriminate cytisine (3 mg/kg s.c.). Rats acquired these discriminations within 50 training sessions. The stimulus effects of both cytisine and nicotine appeared within 4 min of s.c. injection. In generalization tests, rats trained with either cytisine or nicotine showed steep dose-response curves (generalization gradients) for their respective training drug. However, rats trained with cytisine showed full dose-related, generalization to nicotine (93%), whereas rats trained with nicotine exhibited only partial generalization to cytisine (54%). Rats trained with either cytisine or nicotine exhibited similar, partial generalization (76-77%) to (+)-amphetamine. The nicotine antagonist mecamylamine blocked the discriminative stimulus effects of both cytisine and nicotine; it was confirmed that the block of nicotine (0.2 mg/kg) was complete, whereas the block of cytisine (2 and 3 mg/kg) was incomplete in two separate experiments. Overall, the results showed that cytisine, like nicotine, can serve as a robust discriminative stimulus but, in contrast to its relatively high affinity in binding experiments, cytisine was much less potent than nicotine in the behavioural studies. Although the stimulus effects of the two drugs were very similar, there were some subtle differences such as the asymmetrical cross-generalizations between them and possible small differences in susceptibility to antagonism by mecamylamine. These effects were interpreted either in terms of a putative partial agonist effect of cytisine, or by assuming that nicotine produces a compound stimulus. Such a stimulus would be mediated through two or more subtypes of nicotinic receptor, and cytisine would act at some, but not all, of these receptor subtypes.

Gamete intrafallopian transfer

Gamete intrafallopian transfer (GIFT) is a form of assisted reproduction which may be used as an alternative to in vitro fertilization (IVF) in certain circumstances. It is undertaken as a single day-case episode and requires less embryological expertise than IVF. GIFT has been successfully carried out in a number of district general hospitals. The details of the procedure as presently undertaken in Wigan are described.

Ethanol feeding of micropigs alters methionine metabolism and increases hepatocellular apoptosis and proliferation

Chronic alcoholism is associated with increased cancer risk that may be related to ethanol-induced alterations in methionine and deoxynucleotide metabolism. These metabolic relationships were studied in micropigs fed diets for 12 months that contained 40% ethanol or cornstarch control with adequate folate. Ethanol feeding altered methionine metabolism without changing mean terminal liver folate levels. After initial equilibration to diet, ethanol feeding significantly increased monthly serum homocysteine levels while reducing serum methionine levels over the time course of the experiment. After 12 months, hepatic methionine synthase activity and the ratio of S-adenosylmethionine (SAM) to S-adenosylhomocysteine (SAH) were significantly reduced in ethanol-fed animals, whereas the ratio of liver deoxyuridine triphosphate (dUTP) to deoxythymidine triphosphate (dTTP) was increased and correlated inversely with methionine synthase activity. These findings were associated with increased frequency of hepatocytes with apoptotic bodies and positivity for proliferating cell nuclear antigen (PCNA) in livers from ethanol-fed minipigs. These studies suggest that chronic ethanol feeding perturbs methionine metabolism by impairment of methionine synthase activity, resulting in deoxynucleoside triphosphate (dNTP) imbalance, increased apoptosis, and regenerative proliferation. These biochemical alterations may provide a promoting environment for carcinogenesis during long-term ethanol exposure.

Effects of ethanol feeding on liver, kidney and jejunal membranes of micropigs

The micropig model of chronic alcoholism was used to study the relationship of lipid composition and physical properties in three different tissue membranes from the same animals. Ethanol feeding reduced membrane anisotropy, as measured with the diphenylhexatriene probe, in liver plasma and kidney brush-border membranes but not in jejunal brush-border membranes. Preincubation with ethanol reduced anisotropy in each of the three control membranes, whereas all three membranes from the ethanol-fed group were relatively tolerant to the acute effect of ethanol. In liver and kidney membranes, ethanol feeding increased levels of linoleic (18:2 omega 6) acid and decreased levels of arachidonic (20:4 omega 6) and docosahexaenoic (22:6 omega 3) acids and their specific double-bond positions, consistent with reduced activities of delta 6 and delta 5 fatty acid desaturases. In liver and kidney membranes, anisotropy parameters and the acute effect of ethanol correlated inversely with levels of linoleic acid and directly with levels of arachidonic and docosahexaenoic acids and their specific double bonds. Levels of docosahexaenoic acid correlated with the acute effect of ethanol in all three membranes. Phospholipid fatty acid profiles were similar in jejunal brush-border membranes and terminal bile samples, suggesting that the effects of ethanol on jejunal fatty acids and physical properties are modulated by intraluminal biliary phospholipids. The effect of ethanol on anisotropy could not be attributed to changes in membrane cholesterol/phospholipid ratios. These studies affirm the value of this new animal model of chronic alcoholism and provide comprehensive evidence for the central role of fatty acid desaturation in the membrane-associated effects of ethanol exposure.

Centrilobular distribution of acetaldehyde and collagen in the ethanol-fed micropig

We established a new animal model of alcoholic liver disease in the micropig, a species that consumes ethanol voluntarily in the diet. Ten micropigs were pair-fed diets containing 40% of calories as ethanol or cornstarch with identical amounts of fat, protein and micronutrients for 12 mo. Liver histopathology in the ethanol-fed pigs included steatonecrosis in all five and interstitial and perivenous fibrosis in three. Electron microscopy showed Ito-cell transformation with perisinusoidal collagen accumulation. Acetaldehyde adducts were found by immunofluorescence in the centrilobular region and were focused in perivenous zone 3 of all ethanol-fed animals. Protein and triglyceride levels were increased, whereas vitamin A and iron levels were decreased in liver homogenates from ethanol-fed animals. Thus, in this new animal model of alcoholism, ethanol feeding produced the features of alcoholic liver disease concurrent with hepatic deficiency of selected nutrients. Histological and immunofluorescent studies provide in vivo evidence that perivenous collagen deposition is linked to ethanol metabolism and acetaldehyde production.

Functional specificity of jejunal brush-border pteroylpolyglutamate hydrolase in pig

To determine the functional specificity of intestinal brush-border pteroylpolyglutamate hydrolase (PPH), we compared the regional location of in vivo hydrolysis of pteroyltriglutamate (PteGlu3) with the location of activity and immunoreactivity of the enzyme in the pig. After in vivo incubations, PteGlu3 hydrolytic products were recovered from intestinal segments in the jejunum but not from the ileum. Brush-border PPH activity in fractionated mucosa was 10-fold greater in the jejunum than in the ileum, whereas the activity of intracellular PPH was increased in the distal ileum. Antibodies to purified brush-border PPH identified a major protein band at 120 kDa and a minor protein band at 195 kDa in solubilized jejunal brush border. Immunohistochemistry identified the enzyme only on the brush-border surface of the jejunum, whereas an immunoblot of solubilized brush-border membranes identified brush-border PPH in the jejunum but not in the ileum. The parallel of the regional location of in vivo hydrolysis of PteGlu3 with the location of brush-border PPH activity and immunoreactivity demonstrates the functional specificity of this enzyme in folate digestion.

Hemodynamics after hemorrhage during acute ethanol intoxication in newborn piglets

Hemodynamic alterations after hemorrhage were investigated using the microsphere technique in nitrous oxide-anesthetized 2-day-old piglets after acute ethanol intoxication (1.4 g/kg). After hemorrhage (20 ml/kg), mean arterial blood pressure decreased by 34% (p less than 0.01), cardiac output decreased by 58% (p less than 0.01), and systemic vascular resistance increased by 87% (p less than 0.01). In nonintoxicated piglets subjected to hemorrhage, mean arterial blood pressure decreased 17% (p less than 0.01) while alterations in cardiac output and systemic vascular resistance were not significant. Intoxicated piglets had delayed heart rate increases of 11% (p less than 0.01) while heart rate in nonintoxicated piglets increased 27% (p less than 0.01) immediately after hemorrhage. After hemorrhage, arterial perfusion to the liver, kidneys, gastrointestinal organs, and carcass was decreased in intoxicated piglets but only gastrointestinal and carcass perfusion were reduced in nonintoxicated piglets. In summary, acute ethanol intoxication significantly impaired the newborn piglet's cardiovascular response to moderate hypovolemia and delayed the onset of a compensatory tachycardia response. Such cardiovascular impairments may be extremely detrimental to neonates.

Haemodynamic alterations in anaesthetized and acutely intoxicated newborn piglets

1. We investigated the haemodynamic alterations in 2-day old anaesthetized piglets after acute ethanol intoxication using the microsphere technique. 2. After ethanol infusion, mean arterial blood pressure (MABP) decreased by 6%, cardiac output (CO) decreased by 26%, heart rate (HR) increased by 20% and systemic vascular resistance (SVR) increased by 36%. 3. Arterial perfusion to the kidneys, gastrointestinal (GI) organs and carcass decreased by 39%, 34% and 26%, respectively. 4. In piglets pretreated with 4-methylpyrazole (4-MP), an alcohol dehydrogenase inhibitor, the decrease in MABP and increase in HR were not observed after ethanol infusion, but the reduction in CO and increase in SVR were maintained. 5. Arterial blood flow to the GI organs and carcass, but not the kidneys, remained at significantly reduced levels. 6. These observations indicate that ethanol can adversely affect CO and arterial perfusion to GI and musculoskeletal structures while metabolites of ethanol, such as acetaldehyde, affect MABP and HR. Therefore, the clinical effects observed after acute ethanol intoxication in neonates may vary with their rate of ethanol metabolism.

Seizure promotion and protection by D-1 and D-2 dopaminergic drugs in the mouse

Mice injected with pilocarpine (100-400 mg/kg plus 1 mg/kg methylscopolamine), picrotoxin (0.75-6 mg/kg) or strychnine (0.75-6 mg/kg) exhibited clonic or clonic/tonic convulsions. Pretreatment with the D-1 agonist CY 208-243 (0.375-1.5 mg/kg) dose-dependently potentiated the convulsions elicited by 100 mg/kg pilocarpine, but had neither a convulsant nor anticonvulsant effect in mice receiving picrotoxin (3 or 6 mg/kg) or strychnine (0.75 or 1.5 mg/kg). This facilitatory effect of CY 208-243 was abolished by the D-1 antagonist SCH 23390 (0.2 mg/kg). SCH 23390 by itself (0.05-0.8 mg/kg) dose-dependently protected mice against pilocarpine (400 mg/kg) seizures. Stimulating D-2 receptors with LY 171555 (0.167-4.5 mg/kg) dose-dependently protected mice against seizure activity induced by pilocarpine, but neither protected nor sensitised mice given picrotoxin or strychnine. The neuroleptics haloperidol (1-4 mg/kg), sulpiride (10-50 mg/kg), metoclopramide (1.25-6.25 mg/kg), thioridazine (0.5-2 mg/kg) and clozapine (0.5-2 mg/kg) had no effect on the seizure threshold to 100 mg/kg pilocarpine by themselves, although 10 mg/kg thioridazine and clozapine caused 100% convulsions, possibly through a toxic action. When administered in conjunction with a minimally effective quantity of CY 208-243 (0.375 mg/kg), however, all five neuroleptics interacted synergistically with the D-1 agonist to promote convulsions to pilocarpine (100 mg/kg). No such interaction occurred between submaximally protective doses of the D-1 blocker SCH 23390 (0.05 and 0.2 mg/kg) and a wide range of doses of the D-2 stimulant LY 171555 (0.167-4.5 mg/kg).(ABSTRACT TRUNCATED AT 250 WORDS)

Opposite effects of stimulation of D1 and D2 dopamine receptors on the expression of motor seizures in mouse and rat

The ability of drugs, selective for dopamine D1 and D2 receptors, to influence the production of motor seizures was studied in mice and rats. Mice, which had been injected with reserpine (5 mg/kg) to deplete stores of monoamines in brain, could be made to convulse 24 hr later by injecting the D1 agonists, SKF 38393 (15-30 mg/kg) and CY 208-243 (0.3-3 mg/kg). The D2 agonists, lisuride (0.5-5 mg/kg) and RU 24213 (0.5-15 mg/kg) and the mixed D1/D2 agonist, apomorphine (0.05-0.5 mg/kg), had no effect on the seizure thresholds by themselves. However, the proconvulsant action of SKF 38393, 15 mg/kg, was prevented by the simultaneous injection of lisuride (5 mg/kg), RU 24213 (5 mg/kg) or apomorphine (0.5 mg/kg) and also by the selective D1 blocking drug, SCH 23390 (0.1 mg/kg). Rats were made to convulse by injecting the cholinergic agonist, pilocarpine (200-600 mg/kg) coupled with methyl scopolamine (1 mg/kg), to prevent peripheral autonomic effects. The smallest dose of pilocarpine (200 mg/kg) was subconvulsant, whereas the larger ones (400 and 600 mg/kg) dose-dependently induced tonic convulsions. The drug SKF 38393 (30 mg/kg) was found to be proconvulsant and caused seizures to develop in 100% of animals, at all dose levels of pilocarpine. This effect was blocked by SCH 23390 (0.25 mg/kg) which, by itself, reduced the severity and increased the latency of pilocarpine-induced convulsions, but not their frequency. The D2 agonist LY 171555 (0.5 mg/kg) was also anticonvulsant in this model and was antagonised by the D2 blocking drug metoclopramide (1.25 mg/kg), which was ineffective alone.

The synthesis, stability and biological activity of bis-intercalating bis-daunomycin hydrazones

The synthesis of a series of bis-daunomycin hydrazones (5a-g)--all moderately stable at 37 degrees C, pH 6.8, with a half-life of approximately 30 h--is reported. Under a pulse exposure of 2 h they exhibited growth inhibition of mouse L1210 cells, and were 2-3 fold more active than daunomycin. Under continuous exposure growth inhibition conditions with human colon cell lines (HT-29 and HCT-8) they hydrolysed to daunomycin and a partially hydrolysed mono-derivative of daunomycin, and there was no apparent increase in activity over that of the parent anthracycline. Their rate of hydrolysis was observed to increase rapidly with decreasing pH.

Differential behavioural interactions between the dopamine D-1 antagonist SCH 23390 and the dopamine D-2 antagonists metoclopramide and sulpiride in nonhabituated mice

This study investigated the effects of the selective D-1 antagonist SCH 23390, when administered alone and in combination with a typical (metoclopramide) or atypical neuroleptic (sulpiride), on species-typical behaviours in nonhabituated mice. When tested singly, all three compounds caused a progressive dose-dependent inhibition of locomotion, rearing and grooming, though their potencies varied widely. Mixtures of a threshold dose of 0.01 mg/kg SCH 23390 and metoclopramide (0.05-1.25 mg/kg) interacted synergistically to promote hypomotility and to decrease rearing, but did not affect grooming. By contrast, combinations of 0.01 mg/kg SCH 23390 and sulpiride (2-10 mg/kg) resulted in a marked potentiation of grooming, but only additive reductions in horizontal and vertical movements, consistent with sulpiride and metoclopramide occluding different populations of D-2 receptors. The results show that blockade of D-1 receptors and certain populations of D-2 receptors can interact positively to modify animal motor behaviour, and add a fresh perspective to the concept that these two types of dopamine receptor normally work interdependently to control movements of the body.

Motor depression: a new role for D1 receptors?

The aims of this study were two-fold. Firstly, to characterize the behavioral properties of a potential new dopamine D1 receptor agonist, (-)-4,6,6a,7,8,12b-hexahydro-7-methyl-indolo[4,3-ab]phenanth ridine (CY 208-243), to determine its suitability as a tool for investigating D1 receptor function in vivo. Secondly, to investigate how the behavioural properties of D1 agonists are modified in the presence of D2 receptor blocking drugs. For this purpose, using mice, we employed CY 208-243 and 2,3,4,5-tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine hydrochloride (SKF 38393) as reference D1 agonists, and the substituted benzamides metoclopramide and sulpiride as selective D2 antagonists. CY 208-243 (0.25-10 mg/kg) caused only a modest increase in grooming in non-habituated mice, but stimulated locomotion, rearing, grooming and orofacial activities in habituated animals. These responses were inhibited by a D1 antagonist, but not by D2 antagonists, suggesting CY 208-243 behaves as a selective agonist of D1 receptors in vivo. In non-habituated mice, doses of metoclopramide and sulpiride which had little or no effect on motor behaviour by themselves, interacted synergistically with CY 208-243 (4 mg/kg) and SKF 38393 (30 mg/kg) to cause extended periods of immobility. Other species-typical behaviours were not affected in this way. For example, grooming was decreased by metoclopramide and increased by sulpiride, indicating that an increase in behavioural competition from this parameter was not the cause of the hypokinesia. To explain the apparent ability of D1 receptor stimulation to increase exploratory activity in earlier experiments and to decrease it here, it is proposed that this behaviour is regulated by D1 receptors coupled to two functionally opposite postsynaptic D2 receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Folate absorption in alcoholic pigs: in vitro hydrolysis and transport at the intestinal brush border membrane

We used the miniature pig to evaluate the effect of ethanol ingestion on the hydrolysis of pteroylpolyglutamate and on the uptake of pteroylmonoglutamate (PteGlu) by the intestinal brush border membrane, processes that are required for folate absorption. After feeding ethanol or sucrose at 60% of calories for 11 mo, the uptake of PteGlu by jejunal brush-border-membrane vesicles was similar in both groups of animals. Jejunal brush border pteroylpolyglutamate hydrolase was decreased by one-half in the ethanol-fed group. Jejunal brush-border-membrane fluidity, measured by fluorescence polarization, was similar in both groups. Acute exposure of the jejunal vesicles to ethanol increased membrane fluidity and decreased hydrolase activity but had no effect on PteGlu transport. Inhibition of jejunal folate hydrolase by chronic exposure to ethanol may be an early effect in the pathogenesis of folate malabsorption and deficiency in chronic alcoholism.

Kinetic disposition of ethanol in the neonatal piglet and hemodynamic effects in the presence and absence of 4-methylpyrazole

The hemodynamic effects of acute ethanol intoxication and the kinetic disposition of ethanol are reported for the first time in neonatal piglets under nitrous oxide anesthesia. Two hours after a single dose of ethanol (1.4 g/kg), blood pressure decreased from 76 +/- 4 to 71 +/- 4 mm Hg (p less than 0.05) and heart rate increased from 194 +/- 10 to 227 +/- 8 beats/min (p less than 0.05; means +/- SE). By 5 hr, blood pressure dropped to 67.5 +/- 4 mm Hg and heart rate increased to 239 +/- 8 beats/min. In piglets pretreated with 4-methylpyrazole, an alcohol dehydrogenase inhibitor, there was a transient increase in blood pressure (p less than 0.05) and a decrease in heart rate (p less than 0.05) immediately after the end of the ethanol infusion. However, the hemodynamic alterations observed 2 hr after ethanol treatment alone were prevented with 4-methylpyrazole. These findings indicate that ethanol metabolites play a significant role in hemodynamic alterations observed after acute ethanol intoxication. The mean ethanol metabolic rate derived from plasma data was 94 +/- 9 mg/liter/hr. This corresponded to an apparent Km of 68 +/- 3 mg/liter and a Vm of 123 +/- 11 mg/liter/hr. The Vd was 0.966 +/- 0.031 liter/kg. The metabolic rate for ethanol, derived from plasma data, correlated with in vitro alcohol dehydrogenase activity at pH 7.4 and 25 and 37 degrees C. The optimum pH for hepatic alcohol dehydrogenase activity was 9.9.

A Novel Route to the Dibenzofuran Ring System: Possible Applications as a Rigid Thyroid Hormone Template

Photochemical cyclization reactions of iodinated diphenyl ethers to produce dibenzofuran derivatives have been studied. While U.V. irradiation of the thyroid hormone thyroxine produces a complex mixture of products, treatment of the thyroid hormone analogue 3,5-diiodo-4-(4'-methyoxphenoxy)nitrobenzene with U.V. light yielded 4-iodo-8-methoxy-2-nitrodibenzofuran (34%) in a clean reaction. The functionalized dibenzofuran framework produced in this reaction has considerable potential for the development of novel, rigid thyroid hormone analogues.

Fast atom bombardment mass spectrometry of some anthracycline and bisanthracycline derivatives

Fast atom bombardment (FAB) mass spectra of daunomycin, four of its derivatives, seven bisanthracyclines and three mixed-functional daunomycin-acridine derivatives are reported. These anthracyclines all exhibited their expected [MH]+ ions and peaks corresponding to the fragmentations which are characteristic of the anthracycline moiety, and in addition the spectra showed enhanced [MH + n]+ (n = 1-4) ions which were attributed to reductive processes occurring in the liquid matrix under FAB conditions. Daunomycin was also observed to form a dimeric cluster ion [M2H]+ together with associated reduced ions under FAB conditions. We have found that FAB mass spectrometry is an ideal method for the qualitative analysis of large, non-volatile derivatives of anthracyclines.

The DNA-association and biological activity of a new bis(14-thiadaunomycin)

A new bis-daunomycin has been synthesized and characterized by 13C-n.m.r. and reversed-phase h.p.l.c. The compound was found to be highly self-associated in aqueous solution and to bis-intercalate into DNA with a residence time about 200-fold greater than the parent compound daunomycin. Although the bis-daunomycin and its parent congener were taken up by V79 Chinese hamster ovarian leukaemia cells to similar extents, the cytotoxicity of the former was considerably lower. The possible in vivo relationship between DNA binding affinity and cytotoxicity is discussed.

Cation-Binding Properties of Macrocyclic Polyether and Polythioether Diesters and Dithioesters From 1,10-Phenanthrolines and 1,8-Naphthyridines

The cation-binding properties of the title compounds (1)-(7) with the alkali, alkaline-earth, silver, ammonium and copper(II) picrates have been determined from host/guest complexation experiments. The association constants depend on the ligand cavity diameter, the nature of the heterocycle , the type and number of donor atoms and charge on the complexed cation. Dynamic 1H n.m.r . spectroscopy has also been employed, to demonstrate the comparable stability of a 21-membered 1,10-phenanthrolino ligand to its pyridine analogue in binding a benzylammonium salt. From this study, information on both the complex and ligand conformations was obtained.

Preparation and Structural Characterization of a Diaza 21-Crown-7 Ether Complex With Barium Picrate - (3,6,9,12,15-Pentaoxa-26,29-Diazatetracyclo[15.8.4.020,28.023,27]-Nonaco Sa-17,19,21,23,25(1),26,28-Heptaene-2,16-Dione)Barium(II) Picrate

The synthesis, characterization and crystal stucture of the title complex is reported. The triclinic crystals belong to the space group Pī with a 12.726(5), b 14.284(5), c 11.094(5)Ǻ, α 95.76(5),β 93.42(4), γ 88.66(5)� and Z 2. Refinement with 5365 diffractometer data measured with Cu Kα radiation converged at R 0.096. The barium ion is coordinated by a diaza 21-crown-7 ether ligand , which incorporates a phenanthroline moiety, and by two bidentate picrate anions, and thus has 11-coordination. The Ba -O bonds range from 2.62(1) to 3.02(1)Ǻ and the Ba -N bonds have lengths of 3.00(1) and 3.05(1)Ǻ. Disorder is evident in the aliphatic chain of the polyether and, apart from the orientation about a C-O bond in the disordered segment of the chain, the angles about the C-O and C-C bonds define gauche and anti conformations respectively.