Papillorenal Syndrome-Causing Missense Mutations in PAX2/Pax2 Result in Hypomorphic Alleles in Mouse and Human

Papillorenal syndrome (PRS, also known as renal-coloboma syndrome) is an autosomal dominant disease characterized by potentially-blinding congenital optic nerve excavation and congenital kidney abnormalities. Many patients with PRS have mutations in the paired box transcription factor gene, PAX2. Although most mutations in PAX2 are predicted to result in complete loss of one allele's function, three missense mutations have been reported, raising the possibility that more subtle alterations in PAX2 function may be disease-causing. To date, the molecular behaviors of these mutations have not been explored. We describe a novel mouse model of PRS due to a missense mutation in a highly-conserved threonine residue in the paired domain of Pax2 (p.T74A) that recapitulates the ocular and kidney findings of patients. This mutation is in the Pax2 paired domain at the same location as two human missense mutations. We show that all three missense mutations disrupt potentially critical hydrogen bonds in atomic models and result in reduced Pax2 transactivation, but do not affect nuclear localization, steady state mRNA levels, or the ability of Pax2 to bind its DNA consensus sequence. Moreover, these mutations show reduced steady-state levels of Pax2 protein in vitro and (for p.T74A) in vivo, likely by reducing protein stability. These results suggest that hypomorphic alleles of PAX2/Pax2 can lead to significant disease in humans and mice

Feasibility of Implementing a Low-Barrier Long-Acting Injectable Antiretroviral Program for HIV Treatment and Prevention for People Experiencing Homelessness

BackgroundLong-acting (LA) antiretrovirals may provide meaningful benefit to people who use drugs and people experiencing homelessness (PEH) who face disproportionate structural and psychosocial barriers in adhering to daily oral HIV antiretroviral therapy or pre-exposure prophylaxis (PrEP), but their use in these populations has not been studied.SettingThe Maria X. Martinez Health Resource Center is a low-barrier (eg, no appointment) community-based clinic serving San Francisco PEH.MethodsA multidisciplinary care model with robust monitoring and outreach support was developed to provide LA antiretroviral therapy (ART) and LA-PrEP to eligible patients experiencing difficulties adhering to oral antiretrovirals. Feasibility was assessed by evaluating the rates of HIV viremia and on-time injections among patients receiving LA antiretrovirals over the first 24 months of program implementation.ResultsBetween November 2021 and November 2023, 33 patients initiated LA-ART or LA-PrEP (median age, 37 years; 27% transgender/nonbinary; 73% non-White; 27% street homeless; 52% sheltered homeless; 30% with opioid use disorder; 82% with methamphetamine use disorder). Among 18 patients with HIV, 14 initiated LA-ART injections with detectable viremia (median CD4 count, 340 cells/mm 3 ; mean log 10 viral load, 3.53; SD, 1.62), 8 had never previously been virally suppressed, and all but 1 achieved or maintained virologic suppression (mean, 9.67 months; SD, 8.30). Among 15 LA-PrEP patients, all remained HIV negative (mean, 4.73 months; SD, 2.89). Of 224 total injections administered, 8% were delayed >7 days.DiscussionThe implementation of LA antiretrovirals is feasible in low-barrier, highly supportive clinical settings serving vulnerable PEH. Expansion of such programs will be critical in ending the HIV epidemic

Housing Instability Associated with Return to Stimulant Use among Previously Abstaining Women

Stimulant use among unstably housed individuals is associated with increased risks of psychiatric co-morbidity, violence, HIV transmission, and overdose. Due to a lack of highly effective treatments, evidence-based policies targeting the prevention of stimulant use disorder are of critical importance. However, little empirical evidence exists on risks associated with initiating or returning to stimulant use among at-risk populations. In a longitudinal cohort of unstably housed women in San Francisco (2016-2019), self-reported data on stimulant use, housing status, and mental health were collected monthly for up to 6 months, and factors associated with initiating stimulants after a period of non-use were identified through logistic regression. Among 245 participants, 42 (17.1%) started using cocaine and 46 (18.8%) started using methamphetamine. In analyses adjusting for demographics and socio-structural exposures over the preceding month, experiencing street homelessness was associated with initiating cocaine use (AOR: 2.10; 95% CI: 1.04, 4.25) and sheltered homelessness with initiating methamphetamine use (AOR: 2.57; 95% CI: 1.37, 4.79). Other factors-including race, income, unmet subsistence needs, mental health, and treatment adherence-did not reach levels of significance, suggesting the paramount importance of policies directed toward improving access to permanent supportive housing to prevent stimulant use among unstably housed women

Adiabatic Nano-Focusing of Plasmons by Sharp Metallic Wedges

This paper demonstrates the possibility of efficient adiabatic nano-focusing of plasmons by a sharp triangular metal wedge. Geometrical optics approach and the approximation of continuous electrodynamics are used for the analysis. In particular, it is demonstrated that both the phase and group velocities of an incident anti-symmetric (with respect to the magnetic field) plasmon tend to zero at the tip of the wedge, and the plasmon adiabatically slows down, eventually dissipating in the metal. Typically, the amplitude of the plasmon significantly increases near the wedge tip, but this increase is finite even in the absence of dissipation in the metal. The dependence of the local field enhancement near the tip on structural parameters, dissipation in the metal, angle of incidence, etc. is analyzed in this paper. It is also shown that an anti-symmetric film plasmon can effectively be guided by a triangular metal wedge, forming a wedge plasmon mode that is localized near the tip of the wedge and propagates along this tip. A new existence condition for these localized wedge plasmons is derived and discussed