Salirasib

The per and polyfluoroalkyl substance (PFAS) precursor alternative, 6:2 fluorotelomer sulfonate (6:2 FTS), has been detected globally. The central aim of this work was to evaluate the chronic toxicity of 6:2 FTS for this understudied PFAS. Using the amphibian African clawed frog Xenopus laevis, we tested the main hypothesis that, regardless of sex, the sensitivity of this model to 6:2 FTS would be comparable with that of North American amphibians. Larvae were exposed to 6:2 FTS (1.2–1,200 ppb) from Niewkoop and Faber (NF) stages 51 to 65, which took a range of 24 to 42 days. We found significant growth stimulation at 120 ppb (26% mass increase, 6% snout-vent-length increase) without traditional dose-dependency. This growth stimulation coincided with a nonsignificant developmental delay at 120 ppb (38.0 ± 2.9 vs. 35.5 ± 1.8 days to NF 65). The nonmonotonic response yielded dual no observed effect concentration/lowest observed effect concentration (NOEC/LOEC) interpretations: (1) growth stimulation with a NOEC = 12 ppb and a LOEC = 120 ppb; and (2) adverse effects with a NOEC = 1,200 ppb. Xenopus laevis sensitivity to 6:2 FTS appears comparable with North American native amphibians (reported NOECs: 800–1,800 ppb), although the stimulation response and lack of a dose response complicates their application for assessing ecological risks. Although genetic sexing enabled sex-specific analysis in this species, no differences in sensitivity or accumulation rates were detected. These findings highlight the critical importance of endpoint selection in PFAS risk evaluation and supports previous findings with other amphibians showing that exposure to environmentally relevant 6:2 FTS concentrations should not adversely affect growth and development.

People experiencing homelessness have been disproportionately affected by the overdose crisis in the United States. We assessed whether an association exists between homelessness and fentanyl test strip (FTS) use to avoid drug overdose among people who use drugs in Rhode Island.

We recruited 505 participants aged 18-65 from September 2020 to February 2023 as part of the Rhode Island Prescription Illicit Drug Study (RAPIDS). Baseline data assessed correlates of past-month FTS use through bivariate and multivariable analyses. We used generalized estimating equations (GEE) to estimate the longitudinal association between past-month homelessness and FTS use over 12 months.

At baseline, 19.3 % of the sample reported having used FTS in the past month, which was more commonly reported by those who were experiencing homelessness (22.6 %) compared to those who were housed (14.4 %), p = 0.021. In bivariable GEE analysis, past month homelessness was not associated with past-month FTS use (OR=1.22, 95 %CI: 0.95--1.56, p = 0.117). In multivariable GEE analysis, homelessness was not associated with FTS use, but regular use of crystal methamphetamine was (aOR = 2.13, 95 %CI: 1.42-3.19; p < 0.001). The odds of FTS use among persons recruited in 2023 increased by 165 % (aOR=2.65, 95 %CI: 1.22-5.76; p < 0.001) compared to those recruited in 2020.

We found that housing status was not independently and longitudinally associated with FTS use; however, people who used crystal methamphetamine were more than twice as likely to have used FTS in the past month. Future research exploring how differential housing situations may affect uptake of harm reduction services is needed to prevent fentanyl overdose.