Findings from the First Year of a Federally Funded, Direct-to-Consumer HIV Self-Test Distribution Program - United States, March 2023-March 2024.

In September 2022, CDC funded a nationwide program, Together TakeMeHome (TTMH), to expand distribution of HIV self-tests (HIVSTs) directly to consumers by mail through an online ordering portal. To publicize the availability of HIVSTs to priority audiences, particularly those disproportionately affected by HIV, CDC promoted this program through established partnerships and tailored resources from its Let's Stop HIV Together social marketing campaign. The online portal launched March 14, 2023, and through March 13, 2024, distributed 443,813 tests to 219,360 persons. Among 169,623 persons who answered at least one question on a postorder questionnaire, 67.9% of respondents were from priority audiences, 24.1% had never previously received testing for HIV, and 24.8% had not received testing in the past year. Among the subset of participants who initiated a follow-up survey, 88.3% used an HIVST themselves, 27.1% gave away an HIVST, 11.7% accessed additional preventive services, and 1.9% reported a new positive HIVST result. Mailed HIVST distribution can quickly reach large numbers of persons who have never received testing for HIV or have not received testing as often as is recommended. TTMH can help to achieve the goal of diagnosing HIV as early as possible and provides a path to other HIV prevention and care services. Clinicians, community organizations, and public health officials should be aware of HIVST programs, initiate discussions about HIV testing conducted outside their clinics or offices, and initiate follow-up services for persons who report a positive or negative HIVST result.

Increases in Awareness and Uptake of Dating Apps' Sexual Health Features Among US Men Who Have Sex with Men, 2018 to 2021.

Dating apps are now used by the majority of MSM to meet sexual and romantic partners. While research has demonstrated an association between app use and greater number of sex partners and STIs, dating apps also pose an opportunity for intervention. By advocating for new and improved sexual health features on dating apps, Building Healthy Online Communities (BHOC) aims to increase communication about sexual health on the apps. As a follow-up to our previous paper assessing the uptake of sexual health-related profile options on dating apps through Emory's annual survey of 10,000 MSM in the US, BHOC and Emory partnered to explore the change in uptake over time, again through their annual survey. Among survey participants in 2021, 85% reported using dating apps to meet a partner in the past year, and among this group, 93% reported awareness of sexual health features, up from 77% in 2018 (p < 0.0001). 71% of app users who were aware of features in 2021 reported using one or more sexual health feature, up from 61% in 2018 (p < 0.0001). BHOC will continue to advocate for increased uptake of these features, especially among subgroups with lower levels of uptake.

Impact of HCV Testing and Treatment on HCV Transmission Among Men Who Have Sex With Men and Who Inject Drugs in San Francisco: A Modelling Analysis.

BACKGROUND: Men who have sex with men who ever injected drugs (ever MSM-IDU) carry a high hepatitis C virus (HCV) burden. We estimated whether current HCV testing and treatment in San Francisco can achieve the 2030 World Health Organization (WHO) HCV elimination target on HCV incidence among ever MSM-IDU. METHODS: A dynamic HCV/HIV transmission model among MSM was calibrated to San Francisco data, including HCV antibody (15.5%, 2011) and HIV prevalence (32.8%, 2017) among ever MSM-IDU. MSM had high HCV testing (79%-86% ever tested, 2011-2019) and diagnosed MSM had high HCV treatment (65% ever treated, 2018). Following coronavirus disease 2019 (COVID-19)-related lockdowns, HCV testing and treatment decreased by 59%. RESULTS: Among all MSM, 43% of incident HCV infections in 2022 were IDU-related. Among ever MSM-IDU in 2015, HCV incidence was 1.2/100 person-years (95% credibility interval [CrI], 0.8-1.6). Assuming COVID-19-related declines in HCV testing/treatment persist until 2030, HCV incidence among ever MSM-IDU will decrease by 84.9% (95% CrI, 72.3%-90.8%) over 2015-2030. This decline is largely attributed to HCV testing and treatment (75.8%; 95% CrI, 66.7%-89.5%). Slightly greater decreases in HCV incidence (94%-95%) are projected if COVID-19 disruptions recover by 2025 or 2022. CONCLUSIONS: We estimate that HCV incidence will decline by >80% over 2015-2030 among ever MSM-IDU in San Francisco, achieving the WHO target.

Impact of Racial Categorization on Effect Estimates: An HIV Stigma Analysis.

Suboptimal racial categorization potentially introduces bias in epidemiologic analysis and interpretation, making it difficult to appropriately measure factors leading to racial health disparities. As part of an analysis focused on predictors of experiencing human immunodeficiency status (HIV)-related stigma among men who have sex with men living with HIV in San Francisco, we struggled with the most appropriate ways to categorize people who reported more than 1 racial identity, and we aimed to explore the implications of different methodological choices in this analysis. We fitted 3 different multivariable linear regression models, each utilizing a different approach to racial categorization: the "multiracial," "othering," and "hypodescent" models. We estimated an adjusted risk difference in mean score for reported frequency of experiencing HIV-related stigma on a 4-point scale, adjusting for age, race, gender identity, injection history, housing, mental health concerns, and viral load. Use of a hypodescent model for racial categorization led to a shift in the point estimate through the null for Blacks/African Americans, and it improved precision for that group. However, it obscured the association of increased stigma and race for multiracial people, compared with monoracial counterparts. We conclude that methodological decisions related to racial categorization of participants can dramatically affect race-related study findings in predictor regression models.

Factors associated with stigma related to HIV pre-exposure prophylaxis (PrEP) use among men who have sex with men (MSM).

BACKGROUND: Pre-exposure prophylaxis (PrEP) is a noteworthy scientific development that increases the opportunities for men who have sex with men (MSM) to prevent HIV infection, but stigma is a major barrier to its uptake. This study aims to determine the associations between PrEP-related stigma and individual characteristics among MSM. METHODS: Self-reported cross-sectional data were collected from routine-collected electronic healthcare record data from 4084 MSM receiving PrEP in San Francisco, California, between July 2018 and June 2020. Multivariable logistic regression was performed to determine the associations between individual characteristics and PrEP-related stigma, adjusting for age, race, gender identity, injection history, housing status and mental health status. RESULTS: PrEP-related stigma was experienced by 9.0% of the participants in our study. PrEP-related stigma was significantly associated with being transgender or gender non-conforming (adjusted OR (AOR): 1.81, 95% CI 1.21 to 2.72), having a history of injection drug use (AOR: 2.02, 95% CI 1.18 to 3.46), being unstably housed (AOR: 1.58, 95% CI 1.11 to 2.26) and having mental health concerns (AOR: 1.99, 95% CI 1.35 to 2.92), after controlling for age, race, gender, injection history, housing status and mental health status. CONCLUSION: Participants who reported being transgender or gender non-conforming, having a history of injection drug use, or having mental health concerns were more likely to report experiencing PrEP-related stigma. It is crucial to develop culturally appropriate interventions to reduce PrEP-related stigma among populations who are at high risk of HIV infection and may benefit strongly from improved PrEP uptake.

Gay Dating App Users Support and Utilize Sexual Health Features on Apps.

Men who have sex with men (MSM) frequently meet sex partners through dating apps. Research has demonstrated an association between app use and greater number of sex partners and STIs, but dating apps also pose an opportunity for intervention. By advocating for sexual health features on dating apps, Building Healthy Online Communities (BHOC) aims to increase communication about sexual health among app users. In partnership with Emory University, BHOC added questions to an annual survey of MSM. The questions assessed awareness and uptake of profile fields and sexual health features on the dating apps. Among survey participants, 67% (6737/10,129) reported using dating apps to meet a partner in the past year. Among this group, 77% (4993/6525) reported awareness of sexual health features. 61% of app users (2866/4721) who were aware of them reported using one or more sexual health features. BHOC continues to advocate for increased uptake of these features.

Hepatitis C Care Cascades for 3 Populations at High Risk: Low-income Trans Women, Young People Who Inject Drugs, and Men Who Have Sex With Men and Inject Drugs.

BACKGROUND: To achieve elimination of hepatitis C virus (HCV) infection, limited resources can be best allocated through estimation of "care cascades" among groups disproportionately affected. In San Francisco and elsewhere, these groups include young (age ≤ 30 years) people who inject drugs (YPWID), men who have sex with men who inject drugs (MSM-IDU), and low-income trans women. METHODS: We developed cross-sectional HCV care cascades for YPWID, MSM-IDU, and trans women using diverse data sources. Population sizes were estimated using an inverse variance-weighted average of estimates from the peer-reviewed literature between 2013 and 2019. Proportions of past/current HCV infection, diagnosed infection, treatment initiation, and evidence of cure (sustained virologic response at 12 weeks posttreatment) were estimated from the literature using data from 7 programs and studies in San Francisco between 2015 and 2020. RESULTS: The estimated number of YPWID in San Francisco was 3748; 58.4% had past/current HCV infection, of whom 66.4% were diagnosed with current infection, 9.1% had initiated treatment, and 50% had confirmed cure. The corresponding figures for the 8135 estimated MSM-IDU were: 29.4% with past/current HCV infection, 70.3% diagnosed with current infection, 28.4% initiated treatment, and 38.9% with confirmed cure. For the estimated 951 low-income trans women, 24.8% had past/current HCV infection, 68.9% were diagnosed with current infection, 56.5% initiated treatment, and 75.5% had confirmed cure. CONCLUSIONS: In all 3 populations, diagnosis rates were relatively high; however, attention is needed to urgently increase treatment initiation in all groups, with a particular unmet need among YPWID.

Impact of a Structural Intervention to Address Alcohol Use Among Gay Bar Patrons in San Francisco: The PACE Study.

We evaluated the impact on alcohol intake and blood alcohol concentration (BAC) of a multi-level structural intervention to increase the availability of free water, coupled with messaging on pacing alcohol intake and normative feedback of blood alcohol concentration in a convenience sample of gay bars in San Francisco. Participants (n = 1,293) were recruited among exiting patrons of four gay bars (two intervention bars and two control bars). Participants were surveyed on alcohol intake and BAC was measured by breathalyzer. Prior to the intervention there were no significant differences in baseline alcohol measures between intervention and control bars. Post-intervention there were significant differences on objective and subjective measures of alcohol consumption: 30% of intervention bar participants had BAC% levels over the legal driving limit (0.08%) compared to 43% of control bar participants, p < 0.0001 and 78% of intervention bar participants were above the AUDIT-C cut-off for hazardous drinking compared to 87% in control bars, p < 0.001.

Correction to: Impact of a Structural Intervention to Address Alcohol Use Among Gay Bar Patrons in San Francisco: The PACE Study.

The original version of this article contains an omission in the list of authors for Dr. Adam W. Carrico. The corrected authors list for the article is given in this erratum.

Analyzing the Costs and Impact of the TakeMeHome Program, a Public-Private Partnership to Deliver HIV Self-Test Kits in the United States.

BACKGROUND: HIV testing is an entry point to access HIV care and prevention services. Building Healthy Online Communities developed a website ( TakeMeHome.org ) where participants can order HIV home test kits. The purpose of this study was to analyze the costs and impact of the TakeMeHome program. METHODS: We estimated the costs of TakeMeHome across all participating jurisdictions for the first year of the program. We estimated program costs using purchase orders and invoices, contracts, and allocation of staff time, and the costs included website design, participant recruitment, administration and overhead, HIV self-test kits, and shipping and handling. Primary outcomes of the analysis were total program cost, cost per HIV test, and cost per new HIV diagnosis. RESULTS: The TakeMeHome program distributed 5323 HIV self-tests to 4859 participants over a 12-month period. The total program cost over this period was $314,870. The cost per HIV test delivered was estimated at $59, and the cost per person tested was $65. The program identified 18 confirmed new HIV diagnoses (0.6% positivity) verified with surveillance data in 7 health jurisdictions at $169,890. The cost per confirmed new HIV diagnosis was estimated at $9440. CONCLUSIONS: The TakeMeHome program delivered HIV self-testing at a reasonable cost, and the program may be a cost-effective use of HIV prevention resources. The public-private partnership can be an effective mechanism to validate HIV diagnoses identified with self-testing and provide HIV prevention and linkage to care services.

Comparison of HIV behavioral indicators among men who have sex with men across two survey methodologies, San Francisco, 2004 and 2008.

BACKGROUND: Our goal was to examine whether community-based behavioral surveys can augment data collected for the National HIV Behavioral Surveillance System (NHBS) among men who have sex with men (MSM) in San Francisco. METHODS: We compared estimates of sexual risk behaviors among MSM using data from two cycles of NHBS (2004 and 2008) and outreach surveys conducted by STOP AIDS Project (SAP) during the same years. We compared estimates of unprotected anal intercourse (UAI) and other indicators to assess concordance of estimates across methodologies. RESULTS: Of the 3248 interviews conducted, the NHBS sample included more nonwhite and older MSM, more self-reported HIV positive, and less sexually active men than the SAP sample. Estimates of UAI in the last 6 months were slightly higher in the NHBS survey than in the SAP surveys (2004: 40% vs. 36%, P = 0.03; 2008: 44% vs. 38%, P = 0.08). In 2008, where respondent-partner HIV-discordant status could be measured, estimates of UAI with a potentially discordant partner were similar (12% vs. 12%, P = 0.87). Also, the NHBS and SAP surveys observed similar estimates of UAI by high-risk positioning with potentially discordant partners (HIV-positive men reporting insertive UAI with a potentially HIV-negative partner: 13% vs. 11%, P = 0.45; HIV-negative men reporting receptive UAI with a potentially HIV-positive person: 5% vs. 4%, P = 0.85). CONCLUSIONS: Behavioral estimates drawn from convenience sampling methods can provide informative surveillance estimates of key behavioral indictors that can augment data from more rigorous national HIV behavioral surveillance surveys.

How can we improve online HIV and STD prevention for men who have sex with men? Perspectives of hook-up website owners, website users, and HIV/STD directors.

Internet-based interventions have potential to reduce HIV and STD transmission among men who meet male sexual partners online. From November 2009 to May 2010 we surveyed dating and hook-up website users (n = 3,050), website owners (n = 18), and health department HIV/STD directors (n = 81) to identify structural and behavioral prevention interventions that could be implemented online and which a majority of website users were willing to use, owners were willing to implement, and HIV/STD directors perceived to be effective. A majority of each of the three stakeholder groups agreed on the following: (1) automated HIV/STD testing reminders, (2) local STD test site directories, (3) links to sex-positive safe sex videos, (4) access to sexual health experts, (5) profile options to include safer sex preference, (6) chat rooms for specific sexual interests, (7) filtering partners by their profile information, and (8) anonymous e-card partner notification for STD exposure. Findings help build consensus about how to prioritize resources for implementing online HIV and STD prevention interventions and highlight differences between stakeholders to guide future discussion about how to advance prevention efforts.

Hepatitis C prevalence and key population size estimate updates in San Francisco: 2015 to 2019.

BACKGROUND: In 2017, San Francisco's initiative to locally eliminate hepatitis C virus (HCV) as a public health threat, End Hep C SF, generated an estimate of city-wide HCV prevalence in 2015, but only incorporated limited information about population HCV treatment. Using additional data and updated methods, we aimed to update the 2015 estimate to 2019 and provide a more accurate estimate of the number of people with untreated, active HCV infection overall and in key subgroups-people who inject drugs (PWID), men who have sex with men (MSM), and low socioeconomic status transgender women (low SES TW). METHODS: Our estimates are based on triangulation of data from blood bank testing records, cross-sectional and longitudinal observational studies, and published literature. We calculated subpopulation estimates based on biological sex, age and/or HCV risk group. When multiple sources of data were available for subpopulation estimates, we calculated an average using inverse variance weighting. Plausible ranges (PRs) were conservatively estimated to convey uncertainty. RESULTS: The total number of people estimated to have anti-HCV antibodies in San Francisco in 2019 was 22,585 (PR:12,014-44,152), with a citywide seroprevalence of 2.6% (PR:1.4%-5.0%)-similar to the 2015 estimate of 21,758 (PR:10,274-42,067). Of all people with evidence of past or present infection, an estimated 11,582 (PR:4,864-35,094) still had untreated, active HCV infection, representing 51.3% (PR:40.5%-79.5%) of all people with anti-HCV antibodies, and 1.3% (PR:0.6%-4.0%) of all San Franciscans. PWID comprised an estimated 2.8% of the total population of San Francisco, yet 73.1% of people with anti-HCV antibodies and 90.4% (n = 10,468, PR:4,690-17,628) of untreated, active HCV infections were among PWID. MSM comprised 7.8% of the total population, yet 11.7% of people with anti-HCV antibodies and 1.0% (n = 119, PR:0-423) of those with untreated active infections. Low SES TW comprised an estimated 0.1% of the total population, yet 1.4% of people with HCV antibodies and 1.6% (n = 183, PR:130-252) of people with untreated active infections. CONCLUSIONS: Despite the above-average number (2.6%) of people with anti-HCV antibodies, we estimate that only 1.3% (PR:0.6%-4.0%) of all San Francisco residents have untreated, active HCV infection-likely a reflection of San Francisco's robust efforts to diagnose infection among high-risk groups and initiate curative treatment with as many people as possible. While plausible ranges of infections are wide, these findings indicate that while the overall number of people with anti-HCV antibodies may have increased slightly, the number of people with active HCV infection may have decreased slightly since 2015. This estimate improves upon the 2015 calculations by directly estimating the impact of curative treatment citywide and in subgroups. However, more research is needed to better understand the burden of HCV disease among other subgroups at high risk, such as Blacks/African Americans, people with a history of injection drug use (but not injecting drugs in the last 12 months), people who are currently or formerly incarcerated, and people who are currently or formerly unhoused.

Psychosocial Determinants of HIV Stigma among Men Who Have Sex with Men in San Francisco, California.

BACKGROUND: Stigma and discrimination are major challenges faced by people living with HIV (PLWH), and stigma continues to be prevalent among PLWH. We conducted a cross-sectional study of 584 men who have sex with men (MSM) living with HIV between July 2018 and December 2020, designed to better understand which demographic and behavioral characteristics of MSM living with HIV in San Francisco, California are associated with experience of stigma, so that programs and initiatives can be tailored appropriately to minimize HIV stigma's impacts. METHODS: This analysis was conducted with data from San Francisco AIDS Foundation (SFAF) encompassing services from multiple different locations in San Francisco. Data about the level of HIV-related stigma experienced were collected through a single question incorporated into programmatic data collection forms at SFAF as part of the client record stored in SFAF's electronic health record. We performed linear regression to determine the associations between self-reported experiences of HIV stigma and other characteristics among MSM living with HIV. RESULTS: HIV stigma was low overall among MSM living with HIV who are actively engaged in HIV care in San Francisco; however, it was significantly higher for the age groups of 13-29 years (adjusted risk difference (ARD): 0.251, 95% CI: 0.012, 0.489) and 30-49 years (ARD: 0.205, 95% CI: 0.042, 0.367) when compared to the age group of 50 years and older, as well as people who were homeless (ARD: 0.844, 95% CI: 0.120, 1.568), unstably housed (ARD: 0.326, 95% CI: 0.109, 0.543) and/or having mental health concerns (ARD: 0.309, 95% CI: 0.075, 0.544), controlling for race, injection history, and viral load. CONCLUSIONS: These findings highlight an opportunity to develop culturally, socially, and racially appropriate interventions to reduce HIV stigma among MSM living with HIV, particularly for younger men and those struggling with housing stability and/or mental health.

A Patient-Initiated Digital COVID-19 Contact Notification Tool (TellYourContacts): Evaluation Study.

BACKGROUND: Contact notification is a method used to control the spread of infectious disease. In this process, a patient who tests positive for an infectious disease and public health officials work to identify the patient's close contacts, notify them of their risk of possible exposure to the disease, and provide resources to facilitate the decreased spreading of disease. Contact notification can be done physically in person, via phone call, or digitally through the use of media such as SMS text messages and email. When alerts are made through the latter, it is called digital contact notification. OBJECTIVE: For this study, we aim to perform a preliminary evaluation of the use of the TellYourContacts website, a digital contact notification tool for COVID-19 that can be used confidentially and anonymously. We will gather information about the number of website users and message senders, the types of messages sent, and the geographic distribution of senders. METHODS: Patients who chose to get tested for COVID-19 and subsequently tested positive for the disease were alerted of their positive results through Curative Inc (a COVID-19 testing laboratory) and Healthvana (a results disclosure app). Included in the notification was a link to the TellYourContacts website and a message encouraging the person who tested positive for COVID-19 to use the website to alert their close contacts of exposure risk. Over the course of three months, from May 18, 2020, to August 17, 2020, we used Google Analytics and Microsoft Excel to record data on the number of website users and message senders, types of messages sent, and geographic distribution of the senders. RESULTS: Over the course of three months, 9130 users accessed the website and 1474 unique senders sent a total of 1957 messages, which included 1820 (93%) SMS text messages and 137 (7%) emails. Users sent messages from 40 US states, with the majority of US senders residing in California (49%). CONCLUSIONS: We set out to determine if individuals who test positive for COVID-19 will use the TellYourContacts website to notify their close contacts of COVID-19 exposure risk. Our findings reveal that, during the observation period, each unique sender sent an average of 1.33 messages. The TellYourContacts website offers an additional method that individuals can and will use to notify their close contacts about a recent COVID-19 diagnosis.

Indicators of use of methamphetamine and other substances among men who have sex with men, San Francisco, 2003-2006.

BACKGROUND: Substance use has been associated with high-risk sexual behavior among men who have sex with men (MSM) both in the U.S. and around the world. Recent efforts by local organizations in San Francisco have specifically targeted methamphetamine use in this population. METHODS: We tracked methamphetamine and other substance use among men who have sex with men (MSM) in San Francisco from 2003 to 2006 using an indicator available in community outreach surveys of a prevention education program targeting MSM (n=4602). RESULTS: Overall, use of diverse substances tended to decrease from 2003 to 2006, many significantly so. Reported use of methamphetamine significantly decreased among HIV-negative MSM. However, methamphetamine and alcohol use during sex was associated with unprotected potentially HIV serodiscordant sex. CONCLUSION: Intensified prevention efforts to reduce methamphetamine use in San Francisco may be having some impact; however, strong associations of substance use and high-risk sex persist.

Self-Perceived Viral Load and Sexual Risk Behavior Among Known HIV-Positive MSM in San Francisco, 2014.

BACKGROUND: Self-perceived viral suppression status among men who have sex with men (MSM) may impact HIV risk transmission behaviors. METHODS: We conducted a 2014 cross-sectional survey of MSM in San Francisco and assessed differences in sexual risk behavior among known HIV-positive MSM based on viral suppression of HIV. We collected demographics, self-perceived viral load status, and sexual risk behavior and tested for viral load levels through laboratory assays. Men were categorized in a hierarchical schema of sexual risk behavior categories based on responses to questions regarding recent partners' HIV status, condom use, and sexual positioning. We used Fisher exact tests to assess for differences based on self-perceived viral load status. RESULTS: Out of a sample of 96 known HIV-positive men, 59 men self-reported an undetectable HIV viral load and 9 men self-reported a detectable viral load consented to confirmatory laboratory testing. The sample of self-reported undetectable men had gradually larger proportions of higher-risk sexual practices, whereas the sample of detectable men was evenly distributed across sexual practices. This association was not statistically significant (P = 0.91). CONCLUSION: Self-perceived viral suppression may influence sexual practices of known HIV-positive MSM, but small sample size, especially within the detectable category, hinders our ability to determine statistical significance. More research is necessary to assess how HIV-positive men account for viral load in sexual decision-making practices, and this research may inform resource allocation and clinical recommendations to maintain the health of MSM populations.

O2(-)-mediated impairment of coronary arterial relaxation is prevented by overnight treatment with 1 nM beta-estradiol.

We tested the hypothesis that the ability of coronary arteries to withstand functional damage from superoxide (O(2)(-)) is altered by exposure of the arteries to a physiological concentration of beta-estradiol. Female porcine coronary arterial rings were incubated in an O(2)-CO(2) incubator, under normoxic conditions, at 37 degrees C for 22-24 h. Arteries were then placed in baths containing a physiological salt solution at 37 degrees C with 95% O(2)-5% CO(2) for isometric force recordings. In rings from 14 female pigs, vasorelaxation to A-23187 and diethylamine-NONOate (DEA-NONOate) was determined with and without prior 15-min exposure to 400 microM pyrogallol. Sensitivity (-logM ED(50)) and maximum relaxation to A-23187, but not DEA-NONOate, were significantly impaired by exposure to pyrogallol (pyrogallol treated: 7.39 +/- 0.09, 82 +/- 5%; control: 7.76 +/- 0.11, 99 +/- 1%, means +/- SE; P < 0.01 and P < 0.05, respectively). This effect was attenuated by concurrent exposure to equimolar ascorbate. Arterial rings from 12 separate female pigs were incubated for 22-24 h with or without 1 nM beta-estradiol before pyrogallol exposure. beta-Estradiol significantly enhanced arterial sensitivity to A-23187 and prevented pyrogallol impairment without affecting DEA-NONOate responses. Therefore, superoxide-mediated endothelial damage and impaired endothelium-dependent relaxation of coronary arteries are prevented by overnight exposure of the arteries to a physiological concentration of beta-estradiol.