Barriers and facilitators to retaining a cohort of street-based cisgender female sex workers recruited in Baltimore, Maryland, USA: results from the SAPPHIRE study.

BACKGROUND: Despite experiencing HIV/STIs, violence, and other morbidities at higher rates than the general public, street-based female sex workers are often absent from public health research and surveillance due to the difficulty and high costs associated with engagement and retention. The current study builds on existing literature by examining barriers and facilitators of retaining a street-based cohort of cisgender female sex workers recruited in a mobile setting in Baltimore, Maryland who participated in the SAPPHIRE study. Participants completed interviews and sexual health testing at baseline, 3-, 6-, 9-, and 12-months. METHODS: Retention strategies are described and discussed in light of their benefits and challenges. Strategies included collecting several forms of participant contact information, maintaining an extensive field presence by data collectors, conducting social media outreach and public record searches, and providing cash and non-cash incentives. We also calculated raw and adjusted retention proportions at each follow-up period. Lastly, baseline sample characteristics were compared by number of completed visits across demographic, structural vulnerabilities, work environment, and substance use variables using F-tests and Pearson's chi-square tests. RESULTS: Although there were drawbacks to each retention strategy, each method was useful in tandem in achieving a successful follow-up rate. While direct forms of contact such as phone calls, social media outreach, and email were useful for retaining more stable participants, less stable participants required extensive field-based efforts such as home and site visits that increase the likelihood of random encounters. Overall, adjusted retention exceeded 70% for the duration of the 12-month study. Participants who were younger, recently experienced homelessness, and injected drugs daily were less likely to have completed all or most follow-up visits. CONCLUSION: Retention of street-based female sex workers required the simultaneous use of diverse retention strategies that were tailored to participant characteristics. With familiarity of the dynamic nature of the study population characteristics, resources can be appropriately allocated to strategies most likely to result in successful retention.

Incidence and Predictors of Chlamydia, Gonorrhea and Trichomonas Among a Prospective Cohort of Cisgender Female Sex Workers in Baltimore, Maryland.

BACKGROUND: Cisgender female sex workers (CFSWs) have elevated rates of sexually transmitted infections (STI) yet are underrepresented in targeted programming and research in the United States. We examined the prevalence, incidence and predictors of chlamydia, gonorrhea, and trichomonas infection among CFSW. METHODS: Two hundred fifty street-based CFSWs were recruited into a prospective observational cohort in Baltimore, Maryland using targeted sampling in 2016 to 2017 and completed surveys and STI testing at baseline, 3, 6, 9, and 12 months. Cox proportional hazards regression was used to model the predictors of STI. RESULTS: Mean age was 36 years, and 66.5% of respondents were white. Baseline prevalence of chlamydia, gonorrhea, trichomonas was 10.5%, 12.6%, and 48.5%, respectively. The incidence of chlamydia, gonorrhea, and trichomonas was 14.3, 19.3, 69.1 per 100 person-years. Over one year of observation, past year sex work initiation predicted both chlamydia incidence (adjusted hazard ratio [aHR], 2.7; 95% confidence interval [CI], 1.3-6.0) and gonorrhea incidence (aHR, 1.7; 95% CI, 1.0-2.8). Client sexual violence predicted gonorrhea incidence (aHR, 2.9; 95% CI, 1.2-7.1) and having female sexual partners predicted trichomonas incidence (aHR, 3.4; 95% CI, 1.3-8.5). Having a usual health care provider (aHR, 0.6; 95% CI, 0.5-0.7) was inversely associated with trichomonas. CONCLUSIONS: In this study of urban US street-based CFSW, interpersonal and structural factors differentially predicted STIs, and infection rates remained elevated through follow-up despite regular testing, notification, and treatment referral. Focused and multifaceted interventions for sex workers and their sexual partners are urgently needed.

Habenula-Induced Inhibition of Midbrain Dopamine Neurons Is Diminished by Lesions of the Rostromedial Tegmental Nucleus.

Neurons in the lateral habenula (LHb) are transiently activated by aversive events and have been implicated in associative learning. Functional changes associated with tonic and phasic activation of the LHb are often attributed to a corresponding inhibition of midbrain dopamine (DA) neurons. Activation of GABAergic neurons in the rostromedial tegmental nucleus (RMTg), a region that receives dense projections from the LHb and projects strongly to midbrain monoaminergic nuclei, is believed to underlie the transient inhibition of DA neurons attributed to activation of the LHb. To test this premise, the effects of axon-sparing lesions of the RMTg were assessed on LHb-induced inhibition of midbrain DA cell firing in anesthetized rats. Quinolinic acid lesions decreased the number of NeuN-positive neurons in the RMTg significantly while largely sparing cells in neighboring regions. Lesions of the RMTg reduced both the number of DA neurons inhibited by, and the duration of inhibition resulting from, LHb stimulation. Although the firing rate was not altered, the regularity of DA cell firing was increased in RMTg-lesioned rats. Locomotor activity in an open field was also elevated. These results are the first to show that RMTg neurons contribute directly to LHb-induced inhibition of DA cell activity and support the widely held proposition that GABAergic neurons in the mesopontine tegmentum are an important component of a pathway that enables midbrain DA neurons to encode the negative valence associated with failed expectations and aversive stimuli. SIGNIFICANCE STATEMENT: Phasic changes in the activity of midbrain dopamine cells motivate and guide future behavior. Activation of the lateral habenula by aversive events inhibits dopamine neurons transiently, providing a neurobiological representation of learning models that incorporate negative reward prediction errors. Anatomical evidence suggests that this inhibition occurs via the rostromedial tegmental nucleus, but this hypothesis has yet to be tested directly. Here, we show that axon-sparing lesions of the rostromedial tegmentum attenuate habenula-induced inhibition of dopamine neurons significantly. These data support a substantial role for the rostromedial tegmentum in habenula-induced feedforward inhibition of dopamine neurons.

Strain dependency of the effects of nicotine and mecamylamine in a rat model of attention.

RATIONALE: Processes of attention have a heritable component, suggesting that genetic predispositions may predict variability in the response to attention-enhancing drugs. Among lead compounds with attention-enhancing properties are nicotinic acetylcholine receptor (nAChR) agonists. OBJECTIVES: This study aims to test, by comparing three rat strains, whether genotype may influence the sensitivity to nicotine in the 5-choice serial reaction time task (5-CSRTT), a rodent model of attention. METHODS: Strains tested were Long Evans (LE), Sprague Dawley (SD), and Wistar rats. The 5-CSRTT requires responses to light stimuli presented randomly in one of five locations. The effect of interest was an increased percentage of responses in the correct location (accuracy), the strongest indicator of improved attention. RESULTS: Nicotine (0.05-0.2 mg/kg s.c.) reduced omission errors and response latency and increased anticipatory responding in all strains. In contrast, nicotine dose-dependently increased accuracy in Wistar rats only. The nAChR antagonist mecamylamine (0.75-3 mg/kg s.c.) increased omissions, slowed responses, and reduced anticipatory responding in all strains. There were no effects on accuracy, which was surprising giving the clear improvement with nicotine in the Wistar group. CONCLUSIONS: The findings suggest strain differences in the attention-enhancing effects of nicotine, which would indicate that genetic predispositions predict variability in the efficacy of nAChR compounds for enhancing attention. The absence of effect of mecamylamine on response accuracy may suggest a contribution of nAChR desensitization to the attention-enhancing effects of nicotine.