Craters on the melanoma surface facilitate tumor-immune interactions and demonstrate pathologic response to checkpoint blockade in humans.

Immunotherapy leads to cancer eradication despite the tumor's immunosuppressive environment. Here, we used extended long-term in-vivo imaging and high-resolution spatial transcriptomics of endogenous melanoma in zebrafish, and multiplex imaging of human melanoma, to identify domains that facilitate immune response during immunotherapy. We identified crater-shaped pockets at the margins of zebrafish and human melanoma, rich with beta-2 microglobulin (B2M) and antigen recognition molecules. The craters harbor the highest density of CD8 + T cells in the tumor. In zebrafish, CD8 + T cells formed prolonged interactions with melanoma cells within craters, characteristic of antigen recognition. Following immunostimulatory treatment, the craters enlarged and became the major site of activated CD8 + T cell accumulation and tumor killing that was B2M dependent. In humans, craters predicted immune response to ICB therapy, showing response better than high T cell infiltration. This marks craters as potential new diagnostic tool for immunotherapy success and targets to enhance ICB response.

T-cell responses to ancestral SARS-CoV-2 and Omicron variant among unvaccinated pregnant and postpartum women living with and without HIV in South Africa.

SARS-CoV-2 cell-mediated immunity remains understudied during pregnancy in unvaccinated Black African women living with HIV (WLWH) from low- and middle-income countries. We investigated SARS-CoV-2-specific T-cell responses 1 month following infection in 24 HIV-uninfected women and 15 WLWH at any stage during pregnancy or postpartum. The full-length spike (FLS) glycoprotein and nucleocapsid (N) protein of wild-type (WT) SARS-CoV-2, as well as mutated spike protein regions found in the Omicron variant (B.1.1.529) were targeted by flow cytometry. WT-specific CD4+ and CD8+ T cells elicited similar FLS- and N-specific responses in HIV-uninfected women and WLWH. SARS-CoV-2-specific T-lymphocytes were predominantly TNF-α monofunctional in pregnant and postpartum women living with and without HIV, with fever cells producing either IFN-γ or IL-2. Furthermore, T-cell responses were unaffected by Omicron-specific spike mutations as similar responses between Omicron and the ancestral virus were detected for CD4+ and CD8+ T cells. Our results collectively demonstrate comparable T-cell responses between WLWH on antiretroviral therapy and HIV-uninfected pregnant and postpartum women who were naïve to Covid-19 vaccination. Additionally, we show that T cells from women infected with the ancestral virus, Beta variant (B.1.351), or Delta variant (B.1.617.2) can cross-recognize Omicron, suggesting an overall preservation of T-cell immunity.

Prenatal exposure to the mineralocorticoid receptor antagonist spironolactone disrupts hippocampal area CA2 connectivity and alters behavior in mice.

In the brain, the hippocampus is enriched with mineralocorticoid receptors (MR; Nr3c2), a ligand-dependent transcription factor stimulated by the stress hormone corticosterone in rodents. Recently, we discovered that MR is required for the acquisition and maintenance of many features of mouse area CA2 neurons. Notably, we observed that immunofluorescence for the vesicular glutamate transporter 2 (vGluT2), likely representing afferents from the supramammillary nucleus (SuM), was disrupted in the embryonic, but not postnatal, MR knockout mouse CA2. To test whether pharmacological perturbation of MR activity in utero similarly disrupts CA2 connectivity, we implanted slow-release pellets containing the MR antagonist spironolactone in mouse dams during mid-gestation. After confirming that at least one likely active metabolite crossed from the dams' serum into the embryonic brains, we found that spironolactone treatment caused a significant reduction of CA2 axon fluorescence intensity in the CA1 stratum oriens, where CA2 axons preferentially project, and that vGluT2 staining was significantly decreased in both CA2 and dentate gyrus in spironolactone-treated animals. We also found that spironolactone-treated animals exhibited increased reactivity to novel objects, an effect similar to what is seen with embryonic or postnatal CA2-targeted MR knockout. However, we found no difference in preference for social novelty between the treatment groups. We infer these results to suggest that persistent or more severe disruptions in MR function may be required to interfere with this type of social behavior. These findings do indicate, though, that developmental disruption in MR signaling can have persistent effects on hippocampal circuitry and behavior.

Towards improving stroke services in Africa: Results from the Africa-UK Stroke Partnership [AUKSP] surveys.

BACKGROUND: The African Stroke Organization (ASO) in partnership with the University of Central Lancashire's Stroke Research Team launched the Africa-UK Stroke Partnership (AUKSP). AUKSP undertook two (stroke expert and hospital Stroke Unit (SU)) on-line surveys mapping existing capacity and capability to deliver African stroke care. METHODS: An on-line expert survey tool was sent to 139 stroke experts in 54 African countries October 2021-March 2022 and the hospital SU survey to 120 hospital SUs (identified from the expert survey) June-October 2022. Both survey tools were prepared according to the World Stroke Organisation's Roadmap for Delivering Quality Stroke Care. Completed responses were exported from Qualtrics into Microsoft excel and were analysed descriptively. RESULTS: Forty-five expert responses and 62 hospital SU responses were analysed, representing 54(87%) public hospitals, 7(11%) private and 1(2%) charitable organization. In both surveys, three main priorities for improvement of stroke services were: a rapid and prompt stroke diagnosis; effective primary and secondary stroke prevention, and acute stroke management. Survey findings suggest that there is a low presence of national stroke surveillance systems and registries, and heterogeneity in availability of diagnostic services, SUs, endovascular treatments, and rehabilitation. CONCLUSION: Significant gaps exist in Africa's capacity and capability to deliver essential elements of effective and quality stroke care. Tackling these challenges requires urgent and sustained multi-stakeholder action including: government, administrators, policy makers and other partners. Our survey findings highlight key priority areas for multi-stakeholder engagement and crafting of a pragmatic, prioritized and context-sensitive African Stroke Action Plan.

American society for metabolic and bariatric surgery: intra-operative care pathway for minimally invasive Roux-en-Y gastric bypass.

BACKGROUND: Clinical care pathways help guide and provide structure to clinicians and providers to improve healthcare delivery and quality. The Quality Improvement and Patient Safety Committee (QIPS) of the American Society for Metabolic and Bariatric Surgery (ASMBS) has previously published care pathways for the performance of laparoscopic sleeve gastrectomy (LSG) and pre-operative care of patients undergoing Roux-en-Y gastric bypass (RYGB). OBJECTIVE: This current RYGB care pathway was created to address intraoperative care, defined as care occurring on the day of surgery from the preoperative holding area, through the operating room, and into the postanesthesia care unit (PACU). METHODS: PubMed queries were performed from January 2001 to December 2019 and reviewed according to Level of Evidence regarding specific key questions developed by the committee. RESULTS: Evidence-based recommendations are made for care of patients undergoing RYGB including the pre-operative holding area, intra-operative management and performance of RYGB, and concurrent procedures. CONCLUSIONS: This document may provide guidance based on recent evidence to bariatric surgeons and providers for the intra-operative care for minimally invasive RYGB.

Neurocognitive Latent Factors Associate With Early Tobacco and Alcohol Use Among Adolescent Brain Cognitive Development Study Youth.

PURPOSE: Prospective associations between preadolescent neurocognitive structure and onset of substance use in adolescence have not been examined. This study investigated associations between cognitive structure among youth aged 9 - 10 years and the likelihood of experimentation with tobacco and alcohol by ages 13-14 years. METHODS: A principal component (PC) analysis of nine neurocognitive assessments was used to identify the cognitive structure of unrelated adolescent brain cognitive development study participants (n = 9,655). We modeled associations between neurocognitive PCs and odds of tobacco or alcohol use by ages 13-14 years using generalized linear mixed models with a logit link and random intercept for recruitment sites. Demographics, family conflict, neighborhood safety, and externalizing and internalizing behavior were considered covariates. RESULTS: Four neurocognitive PCs were identified and labeled general ability, executive function, learning and memory, and mental rotation. Mental rotation [odds ratio [OR] = 0.88, p-value = .013] was associated with lower odds of youth tobacco use; the association was stronger among female youth. General ability [OR = 1.20, p-value < .0001] among both males and females, and learning and memory [OR = 1.11, p-value = .024] among females, were associated with increased odds of youth alcohol use. DISCUSSION: Among youth, higher neurocognitive performance was protective for tobacco use but increased the likelihood of alcohol use. Potential sex differences were identified. The role of cognition in processing the social contexts surrounding tobacco and alcohol use in the United States may contribute to the formation of disparate youth expectancies for tobacco and alcohol use.

Perspectives of key interest groups regarding supervised Consumption sites (SCS) and novel virtual harm reduction services / overdose response hotlines and applications: a qualitative Canadian study.

BACKGROUND: Supervised consumption sites (SCS) and overdose prevention sites (OPS) have been implemented across Canada to mitigate harms associated with illicit substance use. Despite their successes, they still contend with challenges that limit their accessibility and uptake. Overdose response hotlines and apps are novel virtual technologies reminiscent of informal "spotting" methods that may address some of the limitations. Here, we strove to qualitatively examine the factors that may encourage or deter utilization of these virtual services and SCS. METHODS: A total of 52 participants across Canada were recruited using convenience and snowball sampling methods. These included people with lived and living experience of substance use, family members of people with lived experience, healthcare providers, community harm reduction workers, and virtual harm reduction operators. Semi-structured telephone interviews were conducted and inductive thematic analysis was performed to identify the themes pertaining to SCS and virtual harm reduction. RESULTS: Participants viewed overdose response hotline and apps as an opportunity to consume substances without being hindered by logistical barriers (e.g., wait times), fear of law enforcement, invasion of privacy, and more. They also noted that these virtual services provided more flexibility for clients who opt for routes of consumption that are not supported by SCS, such as smoking. Overall, SCS was perceived to be better than virtual services at facilitating social connection, providing additional resources/referrals, as well as prompt response to overdose. CONCLUSION: In sum, participants viewed SCS and virtual services as filling different needs and gaps. This study adds to a growing body of literature which informs how virtual harm reduction services can serve as useful adjunct to more standard harm reduction methods.

A Practitioner's Guide to Measuring Procedural Fidelity.

Ensuring high levels of procedural fidelity during behavior-analytic interventions is a crucial component of providing effective behavior-analytic services. However, few resources are available to help guide practitioners through measuring procedural fidelity. In fact, most published behavior-analytic research on procedural fidelity analyzes a single treatment procedure, which might not completely reflect the process of monitoring and addressing the procedural fidelity of a robust treatment package that might be necessary in clinical settings. The purpose of this article is to guide behavior analysts through the process of creating and using procedural fidelity measurement systems, with a focus on direct observation of implementation as a means of fidelity data collection. This process consists of six steps: (1) task analyze treatment procedures into measurable units; (2) assign measures to each treatment component; (3) plan the direct observation; (4) collect procedural fidelity data; (5) analyze and interpret procedural fidelity data; and (6) take action to improve procedural fidelity. Each step is described and discussed in the article.

'It was never about me': A qualitative inquiry into the experiences of psychological support and perceived support needs of family caregivers of people with high-grade glioma.

BACKGROUND: Family caregivers of people with high-grade glioma often report high rates of psychological distress, which has been attributed to the unique aspects of the disease and onerous care demands. Clinical practice guidelines advocate for caregiver support from diagnosis through to end-of-life and bereavement. Yet, research has identified that caregivers' support needs are often overlooked. AIM: To explore caregivers' experiences of psychological support and perceptions of what constitutes optimal psychological support for caregivers in the context of high-grade glioma. DESIGN: Qualitative study involving semi-structured interviews with data analysed using reflexive thematic analysis. SETTING/PARTICIPANTS: Eighteen current (n = 11) and bereaved (n = 7) family caregivers (73% female, aged 33-69 years) of adults with high-grade glioma participated. Interviews explored caregivers' perceptions of psychological support. RESULTS: Two major themes were generated. The first theme, 'It was never about me', reflected caregivers prioritise for people with high-grade glioma to be well supported despite experiencing their own unmet psychological support needs. The second theme, 'Continuous, coordinated and personalised support', highlighted the importance of timely and tailored interventions addressing caregivers' practical, educational and emotional support needs throughout the illness journey. CONCLUSIONS: Caregivers commonly prioritise the support needs of people with high-grade gliomas; yet, have their own distinct needs that vary throughout the illness. Primary care providers have a potential role in facilitating timely access to palliative care, practical support and brain tumour-specific psychological support to meet caregivers' diverse needs across the care continuum in the context of high-grade glioma.

Characterization of spironolactone and metabolites derivatized using Girard's reagent P using mass spectrometry and ion mobility spectrometry.

RATIONALE: Spironolactone is a steroidal drug prescribed for a variety of medical conditions and is extensively metabolized quickly after administration. Measurement of spironolactone and its metabolites remains challenging using mass spectrometry (MS) due to in-source fragmentation and relatively poor ionization using electrospray ionization. Therefore, improved methods of measurements are needed, particularly in the case of small sample volumes. METHODS: Girard's reagent P (GP) derivatization of spironolactone was employed to improve response and provide an MS-based solution to the measurement of spironolactone and its metabolites. We performed ultra-high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESI-MS/MS) and ion mobility spectrometry (IMS)-high-resolution mass spectrometry (HRMS) to fully characterize the GP derivatization products. Analytes were studied in positive ionization mode, and MS/MS was performed using nonresonance and resonance excitation collision-induced dissociation. RESULTS: We observed the successful GP derivatization of spironolactone and its metabolites using authentic chemical standards. A signal enhancement of 1-2 orders of magnitude was observed for GP-derivatized versions of spironolactone and its metabolites. Further, GP derivatization eliminated in-source fragmentation. Finally, we performed GP derivatization and ultra-high-performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS) in a small volume of murine serum (20 µL) from spironolactone-treated and control animals and observed multiple spironolactone metabolites only in the spironolactone-treated group. CONCLUSIONS: GP derivatization was proven to have advantageous mass spectral performance (e.g., limiting in-source fragmentation, enhancing signals, and eliminating isobaric analytes) for spironolactone and its metabolites. This work and the detailed characterization using ultra-high-performance liquid chromatography-high-resolution tandem mass spectrometry (UHPLC-HRMS/MS) and IMS serve as the foundation for future developments in reaction optimization and/or quantitative assay development.

Frontoparietal beta event characteristics are associated with early life stress and psychiatric symptoms in adults.

Recent work has found that the presence of transient, oscillatory burst-like events, particularly within the beta band (15-29 Hz), is more closely tied to disease state and behavior across species than traditional electroencephalography (EEG) power metrics. This study sought to examine whether features of beta events over frontoparietal electrodes were associated with early life stress (ELS) and the related clinical presentation. Eighteen adults with documented ELS (n = 18; ELS + ) and eighteen adults without documented ELS (n = 18; ELS-) completed eyes-closed resting state EEG as part of their participation in a larger childhood stress study. The rate, power, duration, and frequency span of transient oscillatory events were calculated within the beta band at five frontoparietal electrodes. ELS variables were positively associated with beta event rate at Fp2 and beta event duration at Pz, in that greater ELS was associated with higher resting rates and longer durations. These beta event characteristics were used to successfully distinguish between ELS + and ELS- groups. In an independent clinical dataset (n = 25), beta event power at Pz was positively correlated with ELS. Beta events deserve ongoing investigation as a potential disease marker of ELS and subsequent psychiatric treatment outcomes.

Severe acute myositis and myocarditis on initiation of 6-weekly pembrolizumab post-COVID-19 mRNA vaccination.

We describe three cases of critical acute myositis with myocarditis occurring within 22 days of each other at a single institution, all within 1 month of receiving the initial cycle of the anti-PD-1 drug pembrolizumab. Analysis of T cell receptor repertoires from peripheral blood and tissues revealed a high degree of clonal expansion and public clones between cases, with several T cell clones expanded within the skeletal muscle putatively recognizing viral epitopes. All patients had recently received a COVID-19 mRNA booster vaccine prior to treatment and were positive for SARS-CoV2 Spike antibody. In conclusion, we report a series of unusually severe myositis and myocarditis following PD-1 blockade and the COVID-19 mRNA vaccination.

Biophysical Modeling of Frontocentral ERP Generation Links Circuit-Level Mechanisms of Action-Stopping to a Behavioral Race Model.

Human frontocentral event-related potentials (FC-ERPs) are ubiquitous neural correlates of cognition and control, but their generating multiscale mechanisms remain mostly unknown. We used the Human Neocortical Neurosolver's biophysical model of a canonical neocortical circuit under exogenous thalamic and cortical drive to simulate the cell and circuit mechanisms underpinning the P2, N2, and P3 features of the FC-ERP observed after Stop-Signals in the Stop-Signal task (SST; N = 234 humans, 137 female). We demonstrate that a sequence of simulated external thalamocortical and corticocortical drives can produce the FC-ERP, similar to what has been shown for primary sensory cortices. We used this model of the FC-ERP to examine likely circuit-mechanisms underlying FC-ERP features that distinguish between successful and failed action-stopping. We also tested their adherence to the predictions of the horse-race model of the SST, with specific hypotheses motivated by theoretical links between the P3 and Stop process. These simulations revealed that a difference in P3 onset between successful and failed Stops is most likely due to a later arrival of thalamocortical drive in failed Stops, rather than, for example, a difference in the effective strength of the input. In contrast, the same model predicted that early thalamocortical drives underpinning the P2 and N2 differed in both strength and timing across stopping accuracy conditions. Overall, this model generates novel testable predictions of the thalamocortical dynamics underlying FC-ERP generation during action-stopping. Moreover, it provides a detailed cellular and circuit-level interpretation that supports links between these macroscale signatures and predictions of the behavioral race model.

Bridging the Gap in Harm Reduction Using Mobile Overdose Response Services (MORS) in the Context of the COVID-19 Pandemic: A Qualitative Study.

The COVID-19 pandemic introduced additional health challenges for people who use substances (PWUS) amid the overdose crisis. Numerous harm reduction services, including supervised consumption sites (SCS) across Canada, faced shutdowns and reduced operating capacity in order to comply with public health measures. Mobile Overdose Response Services (MORS) are novel overdose prevention technologies that allow those who are unable to access alternative means of harm reduction to consume substances under the virtual supervision of a trained operator. Here, we examine the role of MORS in the context of the COVID-19 pandemic. A total of 59 semi-structured interviews were conducted with the following key interest groups: PWUS, healthcare providers, harm reduction workers, MORS operators, and the general public. Inductive thematic analysis informed by grounded theory was used to identify major themes pertaining to the perception of MORS. As the pandemic shifted the public focus away from harm reduction, many participants viewed MORS as an acceptable strategy to reduce the harms associated with solitary substance and alleviate the sense of isolation driven by social distancing measures. While the pandemic may have increased the utility of MORS, concerns surrounding personal privacy and confidentiality remained. Overall, MORS were perceived as a useful adjunct service to address the unmet needs PWUS during the pandemic and beyond.

Labile Carbon from Artificial Roots Alters the Patterns of N2O and N2 Production in Agricultural Soils.

Labile carbon (C) continuously delivered from the rhizosphere profoundly affects terrestrial nitrogen (N) cycling. However, nitrous oxide (N2O) and dinitrogen (N2) production in agricultural soils in the presence of continuous root C exudation with applied N remains poorly understood. We conducted an incubation experiment using artificial roots to continuously deliver small-dose labile C combined with 15N tracers to investigate N2O and N2 emissions in agricultural soils with pH and organic C (SOC) gradients. A significantly negative exponential relationship existed between N2O and N2 emissions under continuous C exudation. Increasing soil pH significantly promoted N2 emissions while reducing N2O emissions. Higher SOC further promoted N2 emissions in alkaline soils. Native soil-N (versus fertilizer-N) was the main source of N2O (average 67%) and N2 (average 80%) emissions across all tested soils. Our study revealed the overlooked high N2 emissions, mainly derived from native soil-N and strengthened by increasing soil pH, under relatively real-world conditions with continuous root C exudation. This highlights the important role of N2O and N2 production from native soil-N in terrestrial N cycling when there is a continuous C supply (e.g., plant-root exudate) and helps mitigate emissions and constrain global budgets of the two concerned nitrogenous gases.

Is 1 Day of Focused Training in Echocardiographic Assessment Using Subxiphoid-Only (EASy) Examination Enough? A Tertiary Hospital Response to the COVID-19 Crisis and the Use of the EASy Examination to Support Unit-Wide Image Acquisition.

OBJECTIVES: We assessed the efficacy of 1-day training in echocardiography assessment using subxiphoid-only (EASy) followed by supervised image interpretation and decision-making during patient rounds as a novel approach to scaling up the use of point-of-care ultrasound (POCUS) in critically ill patients. DESIGN: Retrospective analysis of medical records and EASy examination images. SETTING: Tertiary care academic hospital. PATIENTS: A total of 14 adults (> 18 yr old) with COVID-19-associated respiratory failure under the care of Albany Medical Center's surge response team from April 6-17, 2020 who received at least one EASy examination. INTERVENTIONS: Residents (previously novice sonographers) were trained in EASy examination using 1 day of didactic and hands-on training, followed by independent image acquisition and supervised image interpretation, identification of hemodynamic patterns, and clinical decision-making facilitated by an echocardiography-certified physician during daily rounds. MEASUREMENTS AND MAIN RESULTS: We recorded the quality of resident-obtained EASy images, scanning time, and frequency with which the supervising physician had to repeat the examination or obtain additional images. A total of 63 EASy examinations were performed; average scanning time was 4.3 minutes. Resident-obtained images were sufficient for clinical decision-making on 55 occasions (87%), in the remaining 8 (13%) the supervising physician obtained further images. CONCLUSIONS: EASy examination is an efficient, valuable tool under conditions of scarce resources. The educational model of 1-day training followed by supervised image interpretation and decision-making allows rapid expansion of the pool of sonographers and implementation of bedside echocardiography into routine ICU patient management.

Impact on patient outcomes of spondyloarthritis-inflammatory bowel disease multi-disciplinary meetings.

OBJECTIVES: To assess the impact on patient outcomes of the spondyloarthritis (SpA) and inflammatory bowel disease (IBD) multidisciplinary team (MDT) meetings in a large university hospital. METHODS: A single-centre retrospective observational case-note review was conducted assessing the outcome of all 226 cases discussed at the SpA-IBD MDT meetings in a large UK university hospital between 2017-2022. RESULTS: A total of 226 patients were discussed. It was deemed that 97% of MDT meetings helped to improve communication between teams, and 100% were educational. A total of 57% of discussions led to an instant change of disease management, while 40% of discussions resulted in a treatment plan that avoided the use of dual advanced therapy. This improved patient safety by reducing immunosuppression. The MDT meetings were highly cost and time efficient; 125 referrals between specialists were avoided, and in 51 cases there was a significant chance of reducing future drug costs. A timely investigation or appointment was arranged following 50% of MDT discussions, helping to clarify the diagnosis and optimise patient care. 9% of meetings enabled drugs to be prescribed to patients that are not yet licenced for the other speciality, thereby improving treatment options available in the management of complex cases. CONCLUSION: The MDT meetings have been beneficial for patients, the clinical team and the institution. This approach might be considered by other rheumatology and gastroenterology departments.

Understanding the barriers and facilitators to implementing and sustaining Mobile Overdose Response Services from the perspective of Canadian key interest groups: a qualitative study.

INTRODUCTION: Unregulated supply of fentanyl and adulterants continues to drive the overdose crisis. Mobile Overdose Response Services (MORS) are novel technologies that offer virtual supervised consumption to minimize the risk of fatal overdose for those who are unable to access other forms of harm reduction. However, as newly implemented services, they are also faced with numerous limitations. The aim of this study was to examine the facilitators and barriers to the adoption of MORS in Canada. METHODS: A total of 64 semi-structured interviews were conducted between November 2021 and April 2022. Participants consisted of people who use substances (PWUS), family members of PWUS, health care professionals, harm reduction workers, MORS operators, and members of the general public. Inductive thematic analysis was used to identify the major themes and subthemes. RESULTS: Respondents revealed that MORS facilitated a safe, anonymous, and nonjudgmental environment for PWUS to seek harm reduction and other necessary support. It also created a new sense of purpose for operators to positively contribute to the community. Further advertising and promotional efforts were deemed important to increase its awareness. However, barriers to MORS implementation included concerns regarding privacy/confidentiality, uncertainty of funding, and compassion fatigue among the operators. CONCLUSION: Although MORS were generally viewed as a useful addition to the currently existing harm reduction services, it's important to monitor and tackle these barriers by engaging the perspectives of key interest groups.

Preference for hotline versus mobile application/countdown-based mobile overdose response services: a qualitative study.

BACKGROUND: In response to the exacerbated rates of morbidity and mortality associated with the overlapping overdose and COVID-19 epidemics, novel strategies have been developed, implemented, operationalized and scaled to reduce the harms resulting from this crisis. Since the emergence of mobile overdose response services (MORS), two strategies have aimed to help reduce the mortality associated with acute overdose including staffed hotline-based services and unstaffed timer-based services. In this article, we aim to gather the perspectives of various key interest groups on these technologies to determine which might best support service users. METHODS: Forty-seven participants from various interested groups including people who use substances who have and have not used MORS, healthcare workers, family members, harm reduction employees and MORS operators participated in semi-structured interviews. Transcripts were coded and analyzed using a thematic analysis approach. RESULTS: Four major themes emerged regarding participant perspectives on the differences between services, namely differences in connection, perceived safety, privacy and accessibility, alongside features that are recommended for MORS in the future. CONCLUSIONS: Overall, participants noted that individuals who use substances vary in their desire for connection during a substance use session offered by hotline and timer-based service modalities. Participants perceived hotline-based approaches to be more reliable and thus potentially safer than their timer-based counterparts but noted that access to technology is a limitation of both approaches.