HIV Risk Behaviors and the Use of Geosocial Networking Dating Apps among Men Who have Sex with Men and Transgender Women in Lima, Peru: a Cross-Sectional Study.

Geosocial networking dating apps (GSN apps) are an increasingly widespread technology used by populations throughout the world to facilitate sexual encounters. Studies from a variety of settings suggest a possible association between GSN app use and HIV risk behaviors, including among sexual and gender minority populations such as men who have sex with men (MSM) and transgender women (TW). However, it remains unclear to what extent GSN apps play a causal role. We explored the relationship between GSN app use and sexual risk behaviors among MSM and TW in Lima, Peru by analyzing data from a multi-site cross-sectional survey assessing both general and partner-specific sexual behaviors. We performed bivariate analysis to estimate the association of GSN app use with different individual and partner-specific factors, then fit multivariable regression models adjusting for age and education. Among 741 total participants (698 MSM, 43 TW), 64% met at least one sex partner in the prior three months using a GSN app. GSN app users were significantly more likely to report engaging in HIV risk behaviors in general, including condomless receptive anal sex, group sex, transactional sex, and sex under the influence of alcohol or drugs. Having condomless anal sex with a given partner was not associated with meeting that partner via GSN app. These findings highlight GSN app users as a particularly vulnerable subpopulation among MSM and TW in Lima. GSN apps could provide a useful vehicle for targeted HIV prevention efforts for priority populations in Peru.

RESUMEN: Las aplicaciones de citas de redes geosociales (aplicaciones GSN) son una tecnología con creciente alcance en todo el mundo usadas para facilitar encuentros sexuales. Diferentes estudios sugieren una posible relación entre uso de aplicaciones GSN y comportamientos de riesgo para VIH entre hombres que tienen sexo con hombres (HSH) y mujeres transgénero (MT). No es claro hasta qué punto aplicaciones GSN tendrían un papel causal directo. Exploramos la relación entre uso de aplicaciones GSN y comportamientos sexuales de riesgo entre HSH y MT en Lima, Perú, analizando datos de una encuesta transversal que evaluó comportamientos sexuales en general y en parejas específicas. Realizamos análisis bivariable para estimar la asociación del uso de aplicaciones GSN con diferentes factores individuales y específicos de la pareja. También aplicamos modelos de regresión multivariables ajustados por edad y educación. Entre 741 participantes totales (698 HSH, 43 MT), 64% conoció al menos a una pareja sexual en los últimos tres meses mediante una aplicación GSN. Los usuarios de aplicaciones GSN fueron significativamente más propensos a reportar comportamientos de riesgo de VIH en general, incluyendo sexo anal receptivo sin condón, y sexo grupal, transaccional y bajo influencia de alcohol o drogas. Tener sexo anal sin condón con una pareja determinada no se asoció con conocer a esa pareja mediante aplicación GSN. Estos hallazgos muestran a usuarios de aplicaciones GSN como una subpoblación particularmente vulnerable entre HSH y MT en Lima. Aplicaciones GSN podrían ser útiles para iniciativas de prevención del VIH en poblaciones prioritarias en Perú.

Acceptability of venue-based HIV testing and prevention interventions for men who have sex with transgender women and transgender women in Lima, Perú: a formative, qualitative study.

BACKGROUND: Despite being at elevated risk for HIV, men who have sex with transgender women (MSTW) are an overlooked population in the global HIV response. Venue-based HIV interventions have previously had success reaching other HIV priority populations, including transgender women (TW). Similar approaches could be applied for MSTW. OBJECTIVE: To evaluate the prospective acceptability of venue-based HIV testing and prevention interventions for MSTW and TW in Lima, Peru. METHODS: In this exploratory qualitative study, we conducted in-depth interviews (IDI) and focus group discussions (FGD) with three types of participants: MSTW (7 IDIs, 1 FGD), TW (1 FGD), and owners of social venues frequented by MSTW/TW in Lima (2 IDIs). We elicited participants' attitudes and perceptions related to the following four hypothetical interventions delivered at social venues in Lima: rapid HIV testing; HIV self-test distribution; condom/lubricant distribution; and enrolment in a mobile app supporting HIV prevention. We performed a mixed deductive-inductive thematic analysis using the framework method, then applied the Theoretical Framework of Acceptability to classify the overall acceptability of each intervention. RESULTS: Condom/lubricant distribution and app-based HIV prevention information were highly acceptable among all participant types. The two HIV testing interventions had relatively lower acceptability; however, participants suggested this could be overcome if such interventions focused on ensuring discretion, providing access to healthcare professionals, and offering appropriate incentives. CONCLUSIONS: Overall, MSTW and TW shared similar favourable attitudes towards venue-based HIV interventions. Venue-based outreach warrants further exploration as a strategy for engaging MSTW and TW in HIV prevention activities.

The STOP COVID 2 Study: Fluvoxamine vs Placebo for Outpatients With Symptomatic COVID-19, a Fully Remote Randomized Controlled Trial.

Background: Prior randomized clinical trials have reported benefit of fluvoxamine ≥200 mg/d vs placebo for patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Methods: This randomized, double-blind, placebo-controlled, fully remote multisite clinical trial evaluated whether fluvoxamine prevents clinical deterioration in higher-risk outpatients with acute coronavirus disease 2019 (COVID-19). Between December 2020 and May 2021, nonhospitalized US and Canadian participants with confirmed symptomatic infection received fluvoxamine (50 mg on day 1, 100 mg twice daily thereafter) or placebo for 15 days. The primary modified intent-to-treat (mITT) population included participants who started the intervention within 7 days of symptom onset with a baseline oxygen saturation ≥92%. The primary outcome was clinical deterioration within 15 days of randomization, defined as having both (1) shortness of breath (severity ≥4 on a 0-10 scale or requiring hospitalization) and (2) oxygen saturation <92% on room air or need for supplemental oxygen. Results: A total of 547 participants were randomized and met mITT criteria (n = 272 fluvoxamine, n = 275 placebo). The Data Safety Monitoring Board recommended stopping early for futility related to lower-than-predicted event rates and declining accrual concurrent with vaccine availability in the United States and Canada. Clinical deterioration occurred in 13 (4.8%) participants in the fluvoxamine group and 15 (5.5%) participants in the placebo group (absolute difference at day 15, 0.68%; 95% CI, -3.0% to 4.4%; log-rank P = .91). Conclusions: This trial did not find fluvoxamine efficacious in preventing clinical deterioration in unvaccinated outpatients with symptomatic COVID-19. It was stopped early and underpowered due to low primary outcome rates. Clinical Trials Registration: ClinicalTrials.gov Identifier: NCT04668950.

Treated HIV Infection and Progression of Carotid Atherosclerosis in Rural Uganda: A Prospective Observational Cohort Study.

Background Although ≈70% of the world's population of people living with HIV reside in sub-Saharan Africa, there are minimal prospective data on the contributions of HIV infection to atherosclerosis in the region. Methods and Results We conducted a prospective observational cohort study of people living with HIV on antiretroviral therapy >40 years of age in rural Uganda, along with population-based comparators not infected with HIV. We collected data on cardiovascular disease risk factors and carotid ultrasound measurements annually. We fitted linear mixed effects models, adjusted for cardiovascular disease risk factors, to estimate the association between HIV serostatus and progression of carotid intima media thickness (cIMT). We enrolled 155 people living with HIV and 154 individuals not infected with HIV and collected cIMT images at 1045 visits during a median of 4 annual visits per participant (interquartile range 3-4, range 1-5). Age (median 50.9 years) and sex (49% female) were similar by HIV serostatus. At enrollment, there was no difference in mean cIMT by HIV serostatus (0.665 versus 0.680 mm, P=0.15). In multivariable models, increasing age, blood pressure, and non-high-density lipoprotein cholesterol were associated with greater cIMT (P<0.05), however change in cIMT per year was also no different by HIV serostatus (0.004 mm/year for HIV negative [95% CI, 0.001-0.007 mm], 0.006 mm/year for people living with HIV [95% CI, 0.003-0.008 mm], HIV×time interaction P=0.25). Conclusions In rural Uganda, treated HIV infection was not associated with faster cIMT progression. These results do not support classification of treated HIV infection as a risk factor for subclinical atherosclerosis progression in rural sub-Saharan Africa. Registration URL: https://www.ClinicalTrials.gov; Unique identifier: NCT02445079.

Sex-on-premise venues, associated risk behaviors, and attitudes toward venue-based HIV testing among men who have sex with men in Lima, Perú.

BACKGROUND: In Perú, HIV disproportionately affects men who have sex with men (MSM). Despite widespread access to treatment, the high rate of new HIV infections has remained unchanged over the last decade. Low knowledge of HIV status associated with late diagnosis is a key factor underlying the high HIV incidence observed in this setting, creating conditions for efficient onward transmission. Improving access to HIV testing and prevention services for those at highest risk is an important public health priority. Sex-on-premise venues (SOPVs) - saunas, sex clubs, pornographic movie theaters, hourly hotels, and bars/discos with areas where sex is permitted - may be opportune sites for outreach; however, further research on SOPVs and the populations who frequent them is needed to inform such efforts. METHODS: We conducted a cross-sectional online survey of adult MSM in Lima, Perú to evaluate patterns of SOPV attendance, associated sexual risk behaviors, and attitudes toward SOPV-based interventions. Participants were recruited through outreach to social media networks affiliated with local LGBTQ-aligned community groups. Our primary analytic objective was to estimate the association of HIV-related sexual risk behaviors and SOPV attendance. Additionally, we performed exploratory analyses to describe risk behavior stratified by SOPV category and to examine the relationship between SOPV attendance and the use of online platforms to meet sex partners. RESULTS: Overall, 389 MSM completed the survey from November 2018 through May 2019, of whom 68% reported attending an SOPV in the last 3 months. SOPV attendance was associated with multiple sexual risk behaviors, including transactional sex, group sex, substance use around the time of sex, and higher number of partners. Over two thirds of SOPV attendees indicated they would accept HIV testing if offered at SOPVs. CONCLUSIONS: SOPV attendance was common among MSM in Lima who participated in our survey, and SOPV attendees reported significantly greater engagement in sexual risk behaviors related to HIV transmission. Attitudes toward hypothetical SOPV-based interventions were generally favorable. These findings suggest that outreach at SOPVs may be an effective mechanism for reaching a particularly high-risk sub-population of MSM in Perú to deliver targeted HIV testing and prevention interventions.

PrEP in the Real World: Predictors of 6-Month Retention in a Diverse Urban Cohort.

The effectiveness of HIV pre-exposure prophylaxis (PrEP) depends on adherence, which requires retention in PrEP care. We sought to examine factors associated with six-month retention in PrEP care among individuals prescribed PrEP between 2011 and 2015 in a large, academic health system in the Bronx, New York. We used multivariable logistic regression to identify factors independently associated with six-month retention. Among 107 patients, retention at 6 months was 42%. In the multivariable analysis, heterosexual individuals were less likely to be retained in PrEP care at 6 months, but individuals who received prescriptions from attending physicians were more likely to be retained in care. Larger prospective studies are needed to better evaluate the individual and health system factors associated with long-term engagement in PrEP care.

A combination SMS and transportation reimbursement intervention to improve HIV care following abnormal CD4 test results in rural Uganda: a prospective observational cohort study.

BACKGROUND: Up to 50 % of HIV-infected persons in sub-Saharan Africa are lost from care between HIV diagnosis and antiretroviral therapy (ART) initiation. Structural barriers, including cost of transportation to clinic and poor communication systems, are major contributors. METHODS: We conducted a prospective, pragmatic, before-and-after clinical trial to evaluate a combination mobile health and transportation reimbursement intervention to improve care at a publicly operated HIV clinic in Uganda. Patients undergoing CD4 count testing were enrolled, and clinicians selected a result threshold that would prompt early return for ART initiation or further care. Participants enrolled in the pre-intervention period (January - August 2012) served as a control group. Participants in the intervention period (September 2012 - November 2013) were randomized to receive daily short message service (SMS) messages for up to seven days in one of three formats: 1) messages reporting an abnormal result directly, 2) personal identification number-protected messages reporting an abnormal result, or 3) messages reading "ABCDEFG" to confidentially convey an abnormal result. Participants returning within seven days of their first message received transportation reimbursements (about $6USD). Our primary outcomes of interest were time to return to clinic and time to ART initiation. RESULTS: There were 45 participants in the pre-intervention period and 138 participants in the intervention period (46, 49, and 43 in the direct, PIN, and coded groups, respectively) with low CD4 count results. Median time to clinic return was 33 days (IQR 11-49) in the pre-intervention period and 6 days (IQR 3-16) in the intervention period (P < 0.001); and median time to ART initiation was 47 days (IQR 11-75) versus 12 days (IQR 5-19), (P < 0.001). In multivariable models, participants in the intervention period had earlier return to clinic (AHR 2.32, 95 %CI 1.53 to 3.51) and earlier time to ART initiation (AHR 2.27, 95 %CI 1.38 to 3.72). All three randomized message formats improved time to return to clinic and time to ART initiation (P < 0.01 for all comparisons versus the pre-intervention period). CONCLUSIONS: A combination of an SMS laboratory result communication system and transportation reimbursements significantly decreased time to clinic return and time to ART initiation after abnormal CD4 test results. TRIAL REGISTRATIONS: Clinicaltrials.gov NCT01579214 , approved 13 April 2012.

Empiric deworming and CD4 count recovery in HIV-infected Ugandans initiating antiretroviral therapy.

BACKGROUND: There is conflicting evidence on the immunologic benefit of treating helminth co-infections ("deworming") in HIV-infected individuals. Several studies have documented reduced viral load and increased CD4 count in antiretroviral therapy (ART) naïve individuals after deworming. However, there are a lack of data on the effect of deworming therapy on CD4 count recovery among HIV-infected persons taking ART. METHODOLOGY/PRINCIPAL FINDINGS: To estimate the association between empiric deworming therapy and CD4 count after ART initiation, we performed a retrospective observational study among HIV-infected adults on ART at a publicly operated HIV clinic in southwestern Uganda. Subjects were assigned as having received deworming if prescribed an anti-helminthic agent between 7 and 90 days before a CD4 test. To estimate the association between deworming and CD4 count, we fit multivariable regression models and analyzed predictors of CD4 count, using a time-by-interaction term with receipt or non-receipt of deworming. From 1998 to 2009, 5,379 subjects on ART attended 21,933 clinic visits at which a CD4 count was measured. Subjects received deworming prior to 668 (3%) visits. Overall, deworming was not associated with a significant difference in CD4 count in either the first year on ART (ß = 42.8; 95% CI, -2.1 to 87.7) or after the first year of ART (ß =  -9.9; 95% CI, -24.1 to 4.4). However, in a sub-analysis by gender, during the first year of ART deworming was associated with a significantly greater rise in CD4 count (ß = 63.0; 95% CI, 6.0 to 120.1) in females. CONCLUSIONS/SIGNIFICANCE: Empiric deworming of HIV-infected individuals on ART conferred no significant generalized benefit on subsequent CD4 count recovery. A significant association was observed exclusively in females and during the initial year on ART. Our findings are consistent with recent studies that failed to demonstrate an immunologic advantage to empirically deworming ART-naïve individuals, but suggest that certain sub-populations may benefit.

Impact of geographic and transportation-related barriers on HIV outcomes in sub-Saharan Africa: a systematic review.

Difficulty obtaining reliable transportation to clinic is frequently cited as a barrier to HIV care in sub-Saharan Africa (SSA). Numerous studies have sought to characterize the impact of geographic and transportation-related barriers on HIV outcomes in SSA, but to date there has been no systematic attempt to summarize these findings. In this systematic review, we summarized this body of literature. We searched for studies conducted in SSA examining the following outcomes in the HIV care continuum: (1) voluntary counseling and testing, (2) pre-antiretroviral therapy (ART) linkage to care, (3) loss to follow-up and mortality, and (4) ART adherence and/or viral suppression. We identified 34 studies containing 52 unique estimates of association between a geographic or transportation-related barrier and an HIV outcome. There was an inverse effect in 23 estimates (44 %), a null association in 26 (50 %), and a paradoxical beneficial impact in 3 (6 %). We conclude that geographic and transportation-related barriers are associated with poor outcomes across the continuum of HIV care.

GPS-measured distance to clinic, but not self-reported transportation factors, are associated with missed HIV clinic visits in rural Uganda.

OBJECTIVE: Studies of the association between transportation barriers and HIV-related health outcomes have shown both positive and negative effects, possibly because a reliable, validated measure of transportation barriers has not been identified. DESIGN: Prospective cohort study of HIV-infected patients in rural Uganda. METHODS: Participants were enrolled from the HIV clinic at the regional referral hospital in Mbarara, Uganda as part of the Uganda AIDS Rural Treatment Outcomes (UARTO) Study. We collected the following measures of transportation barriers to HIV clinic: global positioning systems (GPS)-tracked distance measured by driving participants to their homes along their typical route; straight-line GPS distance from clinic to home, calculated with the Great Circle Formula; self-reported travel time; and self-reported travel cost. We assessed inter-measure agreement using linear regression, correlation coefficients and κ statistics (by measure quartile) and validated measures by fitting linear regression models to estimate associations with days late for clinic visits. RESULTS: One hundred and eighty-eight participants were tracked with GPS. Seventy-six percent were women, with a median age of 40 years and median CD4 cell count of 193 cells/µl. We found a high correlation between GPS-based distance measures (ß=0.74, P<0.001, R²=0.92, κ=0.73), but little correlation between GPS-based and self-reported measures (all R²≤0.4). GPS-based measures were associated with days late to clinic (P<0.001); but neither self-reported measure was associated (P>0.85). CONCLUSION: GPS-measured distance to clinic is associated with HIV clinic absenteeism and should be prioritized over self-reported measures to optimally risk-stratify patients accessing care in rural, resource-limited settings.

Optimizing network connectivity for mobile health technologies in sub-Saharan Africa.

BACKGROUND: Mobile health (mHealth) technologies hold incredible promise to improve healthcare delivery in resource-limited settings. Network reliability across large catchment areas can be a major challenge. We performed an analysis of network failure frequency as part of a study of real-time adherence monitoring in rural Uganda. We hypothesized that the addition of short messaging service (SMS+GPRS) to the standard cellular network modality (GPRS) would reduce network disruptions and improve transmission of data. METHODS: Participants were enrolled in a study of real-time adherence monitoring in southwest Uganda. In June 2011, we began using Wisepill devices that transmit data each time the pill bottle is opened. We defined network failures as medication interruptions of >48 hours duration that were transmitted when network connectivity was re-established. During the course of the study, we upgraded devices from GPRS to GPRS+SMS compatibility. We compared network failure rates between GPRS and GPRS+SMS periods and created geospatial maps to graphically demonstrate patterns of connectivity. RESULTS: One hundred fifty-seven participants met inclusion criteria of seven days of SMS and seven days of SMS+GPRS observation time. Seventy-three percent were female, median age was 40 years (IQR 33-46), 39% reported >1-hour travel time to clinic and 17% had home electricity. One hundred one had GPS coordinates recorded and were included in the geospatial maps. The median number of network failures per person-month for the GPRS and GPRS+SMS modalities were 1.5 (IQR 1.0-2.2) and 0.3 (IQR 0-0.9) respectively, (mean difference 1.2, 95%CI 1.0-1.3, p-value<0.0001). Improvements in network connectivity were notable throughout the region. Study costs increased by approximately $1USD per person-month. CONCLUSIONS: Addition of SMS to standard GPRS cellular network connectivity can significantly reduce network connection failures for mobile health applications in remote areas. Projects depending on mobile health data in resource-limited settings should consider this upgrade to optimize mHealth applications.

Rethinking the "pre" in pre-therapy counseling: no benefit of additional visits prior to therapy on adherence or viremia in Ugandans initiating ARVs.

BACKGROUND: Many guidelines recommend adherence counseling prior to initiating antiretrovirals (ARVs), however the additional benefit of pre-therapy counseling visits on early adherence is not known. We sought to assess for a benefit of adherence counseling visits prior to ARV initiation versus adherence counseling during the early treatment period. METHODS: We performed a secondary analysis of data from a prospective cohort of HIV-infected patients in Mbarara, Uganda. Adults were enrolled upon initiation of ARVs. Our primary exposure of interest was ARV adherence counseling prior to initiating therapy (versus concurrent with initiation of therapy). Our outcomes of interest were: 1) average adherence >90% in first three months; 2) absence of treatment interruptions >72 hours in first three months; and 3) Viral load >400 copies/ml at the three month visit. We fit univariable and multivariable regression models, adjusted for predictors of ARV adherence, to estimate the association between additional pre-therapy counseling visits and our outcomes. RESULTS: 300 participants had records of counseling, of whom 231 (77%) completed visits prior to initiation of ARVs and 69 (23%) on or shortly after initiation. Median age was 33, 71% were female, and median CD4 was 133 cell/ml. Median 90-day adherence was 95%. Participants who completed pre-therapy counseling visits had longer delays from ARV eligibility to initiation (median 49 vs 14 days, p<0.01). In multivariable analyses, completing adherence counseling prior to ARV initiation was not associated with average adherence >90% (AOR 0.8, 95%CI 0.4-1.5), absence of treatment gaps (AOR 0.7, 95%CI 0.2-1.9), or HIV viremia (AOR 1.1, 95%CI 0.4-3.1). CONCLUSIONS: Completion of adherence counseling visits prior to ARV therapy was not associated with higher adherence in this cohort of HIV-infected patients in Uganda. Because mortality and loss-to-follow-up remain high in the pre-ARV period, policy makers should reconsider whether counseling can be delivered with ARV initiation, especially in patients with advanced disease.

The role of SGK and CFTR in acute adaptation to seawater in Fundulus heteroclitus.

Killifish are euryhaline teleosts that adapt to increased salinity by up regulating CFTR mediated Cl(-) secretion in the gill and opercular membrane. Although many studies have examined the mechanisms responsible for long term (days) adaptation to increased salinity, little is known about the mechanisms responsible for acute (hours) adaptation. Thus, studies were conducted to test the hypotheses that the acute homeostatic regulation of NaCl balance in killifish involves a translocation of CFTR to the plasma membrane and that this effect is mediated by serum-and glucocorticoid-inducible kinase (SGK1). Cell surface biotinyation and Ussing chamber studies revealed that freshwater to seawater transfer rapidly (1 hour) increased CFTR Cl(-) secretion and the abundance of CFTR in the plasma membrane of opercular membranes. Q-RT-PCR and Western blot studies demonstrated that the increase in plasma membrane CFTR was preceded by an increase in SGK1 mRNA and protein levels. Seawater rapidly (1 hr) increases cortisol and plasma tonicity, potent stimuli of SGK1 expression, yet RU486, a glucocorticoid receptor antagonist, did not block the increase in SGK1 expression. Thus, in killifish SGK1 does not appear to be regulated by the glucocorticoid receptor. Since SGK1 has been shown to increase the plasma membrane abundance of CFTR in Xenopus oocytes, these observations suggest that acute adaptation (hours) to increased salinity in killifish involves translocation of CFTR from an intracellular pool to the plasma membrane, and that this effect may be mediated by SGK1.

Killed but metabolically active Salmonella typhimurium: application of a new technology to an old vector.

Previous studies have shown that attenuated salmonellae utilized as vaccine vectors engender strong immune responses; however, balancing immunogenicity with reactogenicity remains problematic. Recent work in other bacteria has shown that photochemical treatment of DNA excision repair mutants ( Delta uvrAB) renders organisms "killed but metabolically active" (KBMA). Here, we extend this concept to Salmonella typhimurium. A strain of attenuated S. typhimurium previously evaluated in human volunteers was further deleted for uvrAB genes and designated CKS362. Photochemical treatment of CKS362 resulted in significant inactivation. These KBMA organisms were metabolically active as shown by radioactive methionine incorporation and lactate dehydrogenase activity. In mice inoculated intraperitoneally, KBMA CKS362 was markedly less reactogenic and stimulated a humoral immune equivalent to its live counterpart. Because the parental strain has previously been found to elicit strong immune responses to Salmonella antigens, we propose CKS362 as a prototype strain to test the immunogenicity of KBMA organisms in humans.

Role of glucocorticoid receptor in acclimation of killifish (Fundulus heteroclitus) to seawater and effects of arsenic.

Killifish are euryhaline teleosts that adapt to rapid changes in the salinity of the seawater. It is generally accepted that acclimation to seawater is mediated by cortisol activation of the glucocorticoid receptor (GR), which stimulates CFTR mRNA expression and CFTR-mediated Cl- secretion by the gill. Because there is no direct evidence in killifish that the GR stimulates CFTR gene expression, quantitative PCR studies were conducted to test the hypothesis that cortisol activation of GR upregulates CFTR mRNA expression and that this response is required for acclimation to seawater. Inhibition of the GR by RU-486 prevented killifish from acclimating to increased salinity and blocked the increase in CFTR mRNA. In contrast, inhibition of the mineralocorticoid receptor by spironolactone had no effect on acclimation to seawater. Thus acclimation to increased salinity in killifish requires signaling via the GR and includes an increase in CFTR gene expression. Because arsenic, a toxic metalloid that naturally occurs in the aquatic environment, has been shown to disrupt GR transcriptional regulation in avian and mammalian systems, studies were also conducted to determine whether arsenic disrupts cortisol-mediated activation of CFTR gene expression in this in vivo fish model and thereby blocks the ability of killifish to acclimate to increased salinity. Arsenic prevented acclimation to seawater and decreased CFTR protein abundance. However, arsenic did not disrupt the GR-induced increase in CFTR mRNA. Thus arsenic blocks acclimation to seawater in killifish by a mechanism that does not disrupt GR-mediated induction of CFTR gene expression.

Safety and immunogenicity of attenuated Salmonella enterica serovar Typhimurium delivering an HIV-1 Gag antigen via the Salmonella Type III secretion system.

BACKGROUND: CKS257 (Salmonella typhimurium SL1344 DeltaphoP/phoQDelta aroA Deltaasd DeltastrA/strB pSB2131) is a live oral vaccine vector expressing HIV Gag. METHODS: HIV Gag was expressed as a fusion protein of a Salmonella Type III secretion system protein SopE, from a balanced lethal asd-based plasmid. Eighteen healthy adults were given single escalating oral doses of 5 x 10(6) to 1 x 10(10)CFU of CKS257 and were monitored for clinical events, shedding and immune responses. RESULTS: Adverse events were mild except at the highest dose. Volunteers shed the organism an average of 5.1 days (range 0-13 days). Eighty-three percent (15/18) of subjects had a mucosal immune response to Salmonella LPS and flagella by IgA ELISPOT assay. Seventy-two percent (13/18) of subjects seroconverted to Salmonella antigens. No volunteer had a response to recombinant Gag as measured by serology, IgA ELISPOT, or immediate ex vivo gamma-interferon ELISPOT response to Gag peptide pools. Two volunteers responded to Gag peptides by IL-2 ELISPOT, and 4 of 10 volunteers receiving >or=5 x 10(8)CFU had a response to HIV peptides in a cultured gamma-interferon ELISPOT assay. CONCLUSIONS: Although immunogenicity of the HIV antigen needs augmentation, the attenuated Salmonella strain proved to be an excellent platform for vaccine development.

Arsenic inhibits CFTR-mediated chloride secretion by killifish (Fundulus heteroclitus) opercular membrane.

Killifish are euryhaline teleosts that normally experience rapid changes in the salinity of the swim water. Acclimation to seawater is mediated by cortisol, which by activating glucocorticoid receptors, upregulates CFTR mediated Cl- secretion in the gill and operculum. Arsenic, a toxic metalloid that naturally occurs in the aquatic environment, has been shown to disrupt glucocorticoid hormone-mediated regulation of genes. Because little is known about the effects of environmentally relevant levels of arsenic on ion channels and salt homeostasis, studies were conducted to examine the effects of arsenic on the ability of killifish to acclimate to increased salinity. Arsenic in the swim water or administered by intraperitoneal injection prevented acclimation. To determine if arsenic blocked acclimation by inhibiting CFTR mediated Cl- secretion (Isc), opercular membranes were isolated and mounted in Ussing chambers and the effects of arsenic on Isc were measured. Arsenic (24 hr exposure) reduced Isc in opercular membranes isolated from salt water acclimated killifish. In addition, arsenic acutely (5-10 minutes) and reversibly inhibited Isc with an IC50 = 4.1 microM (305 ppb) when applied to the apical (seawater) side of the operculum, but not when added to the basolateral side of the operculum. Arsenic (4 microM for 60 minutes) also reduced mitochondrial respiration. Thus, environmentally relevant levels of arsenic block acclimation to seawater in killifish by reversibly inhibiting CFTR-mediated Cl- secretion by the opercular membrane, in part by inhibiting mitochondrial respiration.

Comparison of rectal swabs with fecal cultures for detection of Salmonella typhimurium in adult volunteers.

Rectal swabs are generally considered less sensitive than fecal culture, but there are no data directly comparing human rectal swabs with fecal samples for detection of Salmonella. A phase I clinical study of a live oral attenuated Salmonella typhimurium vaccine strain in volunteers receiving a large known inoculum provided the opportunity to compare concurrent rectal swab and fecal cultures. Of 155 paired samples from 9 volunteers, 65 (42%) were culture positive: 35 (54%) by both methods, 20 (31%) by fecal culture only, and 10 (15%) by swab only. When compared with fecal culture, rectal swabs were 64% sensitive and 90% specific. Rectal swabs are of moderate diagnostic utility for detection of Salmonella and may be useful when collection of fecal samples is impractical.