Antibiotic use during influenza infection augments lung eosinophils that impair immunity against secondary bacterial pneumonia.

A leading cause of mortality after influenza infection is the development of a secondary bacterial pneumonia. In the absence of a bacterial superinfection, prescribing antibacterial therapies is not indicated but has become a common clinical practice for those presenting with a respiratory viral illness. In a murine model, we found that antibiotic use during influenza infection impaired the lung innate immunologic defenses toward a secondary challenge with methicillin-resistant Staphylococcus aureus (MRSA). Antibiotics augment lung eosinophils, which have inhibitory effects on macrophage function through the release of major basic protein. Moreover, we demonstrated antibiotic treatment during influenza infection causes a fungal dysbiosis that drive lung eosinophilia and impair MRSA clearance. Finally, we evaluated three cohorts of hospitalized patients and found eosinophils positively correlated with antibiotic use, systemic inflammation, and worsened outcomes. Altogether, our work demonstrates a detrimental effect of antibiotic treatment during influenza infection that has harmful immunologic consequences via recruitment of eosinophils to the lungs thereby increasing the risk of developing a secondary bacterial infection.

Iron-Containing Seed Particles Enhance α-Pinene Secondary Organic Aerosol Mass Concentration and Dimer Formation.

Secondary organic aerosol (SOA) comprises the majority of submicron particles and is important for air pollution, health, and climate. When SOA mixes with inorganic particles containing transition metals (e.g., Fe), chemical reactions altering physicochemical properties can occur. Here, we study Fe's impact on the formation and chemical composition of SOA formed via dark α-pinene ozonolysis on either (NH4)2SO4 or Fe-containing (NH4)2SO4 seed particles and aged at varying relative humidities (RHs). Aerosol composition was determined using online extractive electrospray ionization mass spectrometry, providing high-resolution chemical and temporal identification of monomers and dimers in the SOA. At high RH, Fe's presence resulted in higher particulate SOA mass concentrations (117 ± 14 µg m-3) than those formed in its absence (70 ± 1 µg m-3). Enhanced mass is coupled with more dimers (C15-20's), attributed to Fenton-driven oligomerization reactions. Experiments with Fe3+-containing seeds showed similar chemical composition and enhanced SOA mass, suggesting a dark reduction pathway to form Fe2+ in the presence of SOA. Overall, Fe's presence at high RH lowers SOA volatility and enhances particulate organic mass and condensed phased reactions of higher volatility species that would normally not participate in SOA formation, which may be important when considering its formation in air quality and climate models.

Second primary malignancies after CAR T-cell therapy: A systematic review and meta-analysis of 5,517 lymphoma and myeloma patients.

PURPOSE: CAR T-cell therapy is a potent immunotherapy for hematologic malignancies, but patients can develop long-term adverse events including second primary malignancies (SPMs) that impact morbidity and mortality. To delineate the frequency and subtypes of SPMs following CAR-T in lymphoma and myeloma, we performed a systematic review and meta-analysis. DESIGN: A literature search was conducted in the MEDLINE, Embase, and CENTRAL (Cochrane) databases. Following extraction of SPM cases and assignment of malignant origin, we analyzed SPM point estimates using random effect models. RESULTS: We identified 326 SPMs across 5,517 patients from 18 clinical trials (CT) and 7 real-world studies (RWS). With a median follow-up of 21.7 months, the overall SPM point estimate was 5.8% (95%CI 4.7-7.2). SPM estimates were associated with treatment setting (CT>RWS), duration of follow-up, and number of prior treatment lines, which were each confirmed as independent study-level risk factors of SPM in a meta-regression model. A subgroup meta-analysis of the four trials that randomized CAR-T versus standard-of-care revealed a similar risk of SPM with either treatment strategy (p=0.92). In a distribution analysis of SPM subtypes, hematologic malignancies were the most common (37%), followed by solid tumors (27%) and non-melanoma skin cancers (16%). T-cell malignancies represented a small minority of events (1.5%). We noted disease- and product-specific variations in SPM distribution. CONCLUSIONS: These data raise awareness of SPM as a clinically relevant long-term adverse event in patients receiving CAR T-cell therapy. However, our findings do not indicate that SPM frequency is higher with CAR-T versus previous standard-of-care strategies.

The central spindle drives anaphase chromosome segregation.

Anaphase chromosome segregation depends on forces exerted by spindle microtubules. In the current model, forces on chromosomes are mediated through the spindle poles: sliding of antiparallel microtubules in the central spindle pushes poles apart, while kinetochore microtubule (kMT) depolymerization pulls chromosomes towards the poles. Here we show that the central spindle is directly linked to the chromosomes rather than the poles in anaphase, based on three lines of evidence. Chromosomes in monopolar spindles can move away from the pole, consistent with forces exerted by antiparallel microtubule sliding. In bipolar spindles, kMT depolymerization is constrained by suppressing central spindle sliding, indicating kinetochore linkage to the central spindle. Finally, increasing the rate of kMT depolymerization slows pole separation without increasing chromosome separation velocity. We conclude that central spindle sliding drives anaphase chromosome separation, while kMT depolymerization limits spindle elongation.

Implications of drug resistance in leprosy: disease course, reactions and the use of novel drugs.

Leprosy remains a significant neglected tropical disease despite the goal of elimination having been achieved in various endemic nations over the past two decades. Reactional episodes complicate the disease course, resulting in deformities and disability. The main aim of treatment is to kill Mycobacterium leprae and decrease the bacterial load, which could help prevent further bacilli transmission. A major concern in breaking the chain of transmission and possibly for recurrent reactions is the role of drug-resistant bacilli. Though some data is available on the background prevalence of drug resistance in leprosy, there is a paucity of studies that look for resistance specifically in leprosy reactions. Administration of long-term steroids or immunosuppressants for chronic and recurrent responses in the presence of drug resistance has the twin effect of perpetuating the multiplication of resistant bacilli and encouraging the dissemination of leprosy. The increasing trend of prescribing second-line drugs for leprosy or type 2 reactions without prior assessment of drug resistance can potentially precipitate a severe public health problem as this can promote the development of resistance to second-line drugs as well. A comprehensive multicenter study, including drug resistance surveillance testing in cases of reactions, is necessary, along with the current measures to stop the spread of leprosy. Here, we have detailed the history of drug resistance in leprosy, given pointers on when to suspect drug resistance, described the role of resistance in reactions, methods of resistance testing, and the management of resistant cases with second-line therapy.

Criteria for assessing evidence for biomarker-targeted therapies in rare cancers-an extrapolation framework.

Background: Advances in targeted therapy development and tumor sequencing technology are reclassifying cancers into smaller biomarker-defined diseases. Randomized controlled trials (RCTs) are often impractical in rare diseases, leading to calls for single-arm studies to be sufficient to inform clinical practice based on a strong biological rationale. However, without RCTs, favorable outcomes are often attributed to therapy but may be due to a more indolent disease course or other biases. When the clinical benefit of targeted therapy in a common cancer is established in RCTs, this benefit may extend to rarer cancers sharing the same biomarker. However, careful consideration of the appropriateness of extending the existing trial evidence beyond specific cancer types is required. A framework for extrapolating evidence for biomarker-targeted therapies to rare cancers is needed to support transparent decision-making. Objectives: To construct a framework outlining the breadth of criteria essential for extrapolating evidence for a biomarker-targeted therapy generated from RCTs in common cancers to different rare cancers sharing the same biomarker. Design: A series of questions articulating essential criteria for extrapolation. Methods: The framework was developed from the core topics for extrapolation identified from a previous scoping review of methodological guidance. Principles for extrapolation outlined in guidance documents from the European Medicines Agency, the US Food and Drug Administration, and Australia's Medical Services Advisory Committee were incorporated. Results: We propose a framework for assessing key assumptions of similarity of the disease and treatment outcomes between the common and rare cancer for five essential components: prognosis of the biomarker-defined cancer, biomarker test analytical validity, biomarker actionability, treatment efficacy, and safety. Knowledge gaps identified can be used to prioritize future studies. Conclusion: This framework will allow systematic assessment, standardize regulatory, reimbursement and clinical decision-making, and facilitate transparent discussions between key stakeholders in drug assessment for rare biomarker-defined cancers.

A comparative analysis of peritoneal flap and intestinal vaginoplasty for management of vaginal stenosis.

BACKGROUND: In transgender or non-binary patients (TGNB) with failed penile inversion vaginoplasty (PIV), peritoneal flap vaginoplasty (PFV) and intestinal segment vaginoplasty (ISV) facilitate restoration of neovaginal depth and sexual function. This study compared the outcomes of revision PFV and ISV in TGNB patients with failed PIV. METHODS: TGNB patients who underwent secondary PFV or ISV from December 2018 to April 2023 were reviewed. RESULTS: Twenty-one (5.8%) patients underwent secondary PFV and 24 (6.6%) underwent secondary ISV, due to vaginal stenosis (n = 45, 100.0%). Mean duration to first successful dilation and average vaginal depth were comparable between the groups. Seven (33.3%) PFV patients experienced short-term complications, including introital dehiscence (n = 2, 9.5%), vaginal stenosis (n = 2, 9.5%), vaginal bleeding (n = 2, 9.5%), and reoperation (n = 2, 9.5%). Nine (42.9%) experienced long-term complications, including urethrovaginal fistula formation (n = 2, 9.5%), hypergranulation (n = 2, 9.5%), vaginal stenosis (n = 7, 33.3%), and reoperation (n = 6, 28.6%). Ten (41.7%) ISV patients experienced short-term complications, including dehiscence (n = 4, 19.0%), ileus (n = 2, 8.3%), introital stenosis (n = 2, 9.5%), and reoperation due to vaginal bleeding (n = 2, 8.3%). Six (25.0%) experienced long-term complications, including introital stenosis (n = 3, 12.5%), mucosal prolapse (n = 2, 8.3%), and reoperation due to mucosal prolapse (n = 4, 16.7%). Secondary PFV had a higher rate of vaginal stenosis (p = 0.003). There were no cases of partial or full-thickness flap necrosis. CONCLUSION: Revision PFV and ISV represent viable techniques for addressing vaginal stenosis secondary to PIV. Although PFV and ISV had comparable rates of short-term complications, ISV demonstrated a lower incidence of recurrent vaginal stenosis, which may inform operative decision-making.

Long term safety and outcomes after atrial shunting for heart failure with preserved or mildly reduced ejection fraction: 5-year and 3-year follow-up in the REDUCE LAP-HF I and II trials.

BACKGROUND: There is a little evidence regarding long-term safety and efficacy for atrial shunt devices in heart failure (HF). METHODS: The REDUCE LAP-HF I (n=44) and II (n=621) trials (RCT-I and -II) were multicenter, randomized, sham-controlled trials of patients with HF and ejection fraction >40%. Outcome data were analyzed from RCT-I, a mechanistic trial with 5-year follow-up, and RCT-II, a pivotal trial identifying a responder group (n=313) defined by exercise PVR <1.74 WU and no cardiac rhythm management device with 3-year follow-up. RESULTS: At 5 years in RCT I, there were no differences in cardiovascular (CV) mortality, HF events, embolic stroke, or new-onset atrial fibrillation between groups. After 3 years in RCT II, there was no difference in the primary outcome (hierarchical composite of CV mortality, stroke, HF events, and KCCQ) between shunt and sham in the overall trial. Compared to sham, those with responder characteristics in RCT-II had a better outcome with shunt (win ratio 1.6 [95% CI 1.2-2.2], P=0.006; 44% reduction in HF events [shunt 9 vs. control 16 per 100 patient-years], P=0.005; and greater improvement in KCCQ overall summary score [+17.9±20.0 vs. +7.6±20.4], P<0.001), while non-responders had significantly more HF events. Shunt treatment at 3 years was associated with a higher rate of ischemic stroke (3.2% vs. 0%, 95% CI 2% - 6.1%, p=0.032) and lower incidence of worsening kidney dysfunction (10.7% vs. 19.3%, p=0.041). CONCLUSIONS: With up to 5 years of follow up, adverse events were low in patients receiving atrial shunts. In the responder group, atrial shunt treatment was associated with a significantly lower HF event rate and improved KCCQ compared to sham through 3 years of follow-up. CLINICALTRIALS: gov registration: NCT02600234, NCT03088033.

Somatic Activating ESR1 Mutation in an Aggressive Prolactinoma.

CONTEXT AND OBJECTIVE: The genetic profile of prolactinomas remains poorly understood. Our objective is to identify somatic genetic alterations associated with prolactinomas and to report the identification of an activating ESR1 mutation (ESR1Y537S) in an aggressive prolactinoma. SETTING: Brigham and Women's Hospital. DESIGN: Massively parallel-sequencing panel (OncoPanel) was performed in a cohort of patients with prolactinomas to identify mutations and copy number variation (CNV). RESULTS: Twenty subjects (mean age 38.6 years; 12 women and 8 men) were included in this study. A somatic ESR1Y537S mutation was identified in an aggressive prolactinoma in a post-menopausal woman. No SF3B1 or other somatic mutations were identified. The median number of CNV events identified in our samples was 46; the prolactinoma with ESR1Y537S had the highest number with 233 events. In breast cancer, ESR1Y537S has been shown to activate estrogen receptor alpha independent of ligand binding. In patients with resistant breast cancer and ESR1Y537S, elacestrant, a second-line ER degrader, improves progression-free survival. Therefore, given the lack of response to multimodality therapies, elacestrant was initiated in this patient after the third cycle of radiotherapy. Elacestrant, along with radiotherapy, controlled tumor growth and significantly reduced prolactin levels. CONCLUSION: Molecular profiling allowed the identification of ESR1Y537S, in an aggressive prolactinoma. ESR1Y537S was not detected early in the course of the disease and is likely conferring tumor aggressiveness. This finding emphasizes the significance of estrogen receptor signaling in prolactinomas. It also allowed the use of targeted therapy with successful control of disease progression.

[Implementation of edoxaban anti-Xa activity assay in a hospital laboratory and evaluation of its analytical performance]. / Mise en place du dosage de l'activité anti-Xa de l'edoxaban dans un laboratoire hospitalier et évaluation de ses performances analytiques.

Edoxaban is a direct oral anticoagulant available in Europe but not in France. Given the high tourist traffic in France, understanding the pharmacology of edoxaban and the availability of its laboratory testing seemed crucial in emergency situations. The aim of this work was to describe the methodology for measuring the anti-Xa activity of edoxaban, highlighting pre-analytical and analytical aspects, along with essential clinico-biological data for therapeutic guidance. The analysis was performed using the chromogenic method on the STAR-Max analyzer, with the STA®-Liquid ANTI-Xa kit (Diagnostica Stago®). Anti-Xa Edoxaban level measurement has a detection limit of 15 ng/mL, a quantification limit of 20 ng/mL and a linearity limit of 400 ng/mL. Repeatability, intermediate precision, accuracy, and measurement uncertainty studies were conducted to assess method performance, meeting quality requirements. The comparison between two STAR-Max® analyzers showed excellent results with linear regression and a low bias with good precision and no loss of dispersion regardless of edoxaban levels. In conclusion, although the measurement of edoxaban level may be rarely necessary in clinical practice, its implementation is straightforward. The availability of edoxaban in neighboring countries, underscores the importance of having its measurement available in hospital laboratories.

Design of an injectable, self-adhesive, and highly stable hydrogel electrode for sleep recording.

High-quality and continuous electroencephalogram (EEG) monitoring is desirable for sleep research, sleep monitoring, and the evaluation and treatment of sleep disorders. Existing continuous EEG monitoring technologies suffer from fragile connections, long-term stability, and complex preparation for electrodes under real-life conditions. Here, we report an injectable and spontaneously cross-linked hydrogel electrode for long-term EEG applications. Specifically, our electrodes have a long-term low impedance on hairy scalp regions of 17.53 kΩ for more than 8 h of recording, high adhesiveness on the skin of 0.92 N cm-1 with repeated attachment capability, and long-term wearability during daily activities and overnight sleep. In addition, our electrodes demonstrate a superior signal-to-noise-ratio of 23.97 decibels (dB) in comparison with commercial wet electrodes of 17.98 dB and share a high agreement of sleep stage classification with commercial wet electrodes during multichannel recording. These results exhibit the potential of our on-site-formed electrodes for high-quality, prolonged EEG monitoring in various scenarios.

Oscillatory-Quality of sleep spindles links brain state with sleep regulation and function.

Here, we characterized the dynamics of sleep spindles, focusing on their damping, which we estimated using a metric called oscillatory-Quality (o-Quality), derived by fitting an autoregressive model to electrophysiological signals, recorded from the cortex in mice. The o-Quality of sleep spindles correlates weakly with their amplitude, shows marked laminar differences and regional topography across cortical regions, reflects the level of synchrony within and between cortical networks, is strongly modulated by sleep-wake history, reflects the degree of sensory disconnection, and correlates with the strength of coupling between spindles and slow waves. As most spindle events are highly localized and not detectable with conventional low-density recording approaches, o-Quality thus emerges as a valuable metric that allows us to infer the spread and dynamics of spindle activity across the brain and directly links their spatiotemporal dynamics with local and global regulation of brain states, sleep regulation, and function.

Youth daily stressors predict their parents' wellbeing.

The experiences of family members are intertwined and the stressors of one family member may crossover to affect the wellbeing of others in the family as well. Prior studies have established that the stress experienced by one marital spouse can affect the wellbeing of their spouse and that parent stress can affect their children's wellbeing. This study used daily diary data from 318 parent-youth dyads (Mean age parent = 41.34, adolescent = 13.18) to examine whether youth daily stressors (i.e., interpersonal conflicts and demands), were associated with parent wellbeing and cortisol levels. Parents report more negative affect, more physical symptoms (i.e., headaches/fatigue/stomach problems), and exhibit higher bedtime cortisol levels on days when youth experience stressors. These effects were consistent across different types of youth stressors, including parent, family, and non-family stressors. Youth stress may have important implications for parent wellbeing.

Starvation Ketoacidosis on the Acute Medical Take: An Easily Missed Complication of the Keto Diet.

Starvation ketoacidosis represents one of the three forms of metabolic acidosis caused by the accumulation of ketone bodies within the blood stream. It can be easily missed in patients who present acutely and are found to have an unexplained or profound metabolic acidosis. Here, we present a life-threatening case of severe ketoacidosis in a breast-feeding mother without diabetes who was on a strict ketogenic diet. Although a ketogenic diet has been previously considered to be safe in non-pregnant individuals, its safety in breast-feeding mothers in the post-partum period is less known and may be associated with greater harm. Health professionals and mothers should be aware of the potential risks associated with a strict ketogenic diet when combined with breast-feeding, especially in the earlier stages of the post-partum period. Prompt investigation, diagnosis and immediate management is vital to avoid life-threatening complications. We report a case admitted on the acute medical take with starvation ketoacidosis associated with ketogenic diet and adequate calorie consumption who was breast-feeding at the time of admission. LEARNING POINTS: Always check ketones in patients with an unexplained metabolic acidosis; there can be overlap between starvation, alcohol-related and lactic acidosis.Management of starvation ketoacidosis is often empirical, involving close monitoring of fluid status and electrolytes.Clinicians should discuss the risk of ketoacidosis associated with the ketogenic diet in women who plan to breast-feed and lose weight following pregnancy.

Association of Tumor Mutational Burden and Microsatellite Instability With Response and Outcomes in Patients With Urothelial Carcinoma Treated With Immune Checkpoint Inhibitor.

BACKGROUND: Microsatellite Instability (MSI) and Tumor Mutational Burden (TMB) are associated with immune checkpoint inhibitor (ICI) efficacy. We examined the association between TMB and MSI status with survival in patients with urothelial carcinoma (UC) treated with ICI. METHODS: Patients from 15 institutions were treated with ICI monotherapy. Primary endpoint was overall survival and secondary endpoints included observed response rate (ORR), and progression-free (PFS) calculated from ICI initiation. TMB was analyzed as dichotomous (≥10 vs. <10 mut/Mb) and continuous variable. RESULTS: We identified 411 patients: 203 were treated with ICI 1L/upfront; 104 with 2 + L. For the 1L/upfront: median [m] OS was numerically longer in patients with TMB ≥10 versus TMB <10: mOS 35 versus 26 months (HR = 0.6) and with MSI-H and MSI-S (mOS NR vs. 22 months), though neither association was statistically significant. A statistically significant association was found between TMB (continuous variable) and OS (HR = 0.96, P = .01). For 2 + L: mOS was numerically longer in patients with TMB ≥10 versus TMB <10: (20 vs. 12 months; HR = 0.9); mOS was 12 and 17 months for patients with MSI-H and MSI-S, respectively. Eighty-nine patients received maintenance avelumab (mAV): mOS was longer in patients with TMB ≥10 versus TMB <10: 61 versus 17 months; (HR = 0.2, P = .02) and with MSI-H and MSI-S (NR vs. 24 months). CONCLUSIONS: Although not reaching statistical significance in several subsets, patients with high TMB and MSI-H had numerically longer OS with ICI, especially with mAV. Further validation is needed.

Reversible Phasonic Control of a Quantum Phase Transition in a Quasicrystal.

Periodic driving can tune the quasistatic properties of quantum matter. A well-known example is the dynamical modification of tunneling by an oscillating electric field. Here we show experimentally that driving the phasonic degree of freedom of a cold-atom quasicrystal can continuously tune the effective quasidisorder strength, reversibly toggling a localization-delocalization quantum phase transition. Measurements agree with fit-parameter-free theoretical predictions, and illuminate a fundamental connection between Aubry-André localization in one dimension and dynamic localization in the associated two-dimensional Harper-Hofstadter model. These results open up new experimental possibilities for dynamical coherent control of quantum phase transitions.

Failure in a population: Tauopathy disrupts homeostatic set-points in emergent dynamics despite stability in the constituent neurons.

Homeostatic regulation of neuronal activity is essential for robust computation; set-points, such as firing rate, are actively stabilized to compensate for perturbations. The disruption of brain function central to neurodegenerative disease likely arises from impairments of computationally essential set-points. Here, we systematically investigated the effects of tau-mediated neurodegeneration on all known set-points in neuronal activity. We continuously tracked hippocampal neuronal activity across the lifetime of a mouse model of tauopathy. We were unable to detect effects of disease in measures of single-neuron firing activity. By contrast, as tauopathy progressed, there was disruption of network-level neuronal activity, quantified by measuring neuronal pairwise interactions and criticality, a homeostatically controlled, ideal computational regime. Deviations in criticality correlated with symptoms, predicted underlying anatomical pathology, occurred in a sleep-wake-dependent manner, and could be used to reliably classify an animal's genotype. This work illustrates how neurodegeneration may disrupt the computational capacity of neurobiological systems.

Understanding Differences in Medical Student Perceptions of Treatment Adherence Based on Weight Status in Pediatric Care.

Obesity biases in healthcare are detrimental. We explored medical student beliefs underlying perceptions that child-mother dyads with obesity are less likely to be treatment adherent. Participants viewed scenes of a 12-year-old, female virtual human presenting to a physician with back pain, accompanied by her mother. Patient and mother weight cues were manipulated across scenes. Out of 120, 35 participants perceived dyads with obesity as less adherent to hypothetical pain-related treatment recommendations relative to dyads with healthy weight. These participants were informed and asked why. Responses were analyzed for themes. Fifty-two responses revealed three codes relating to participants' explanation of why they perceived lower adherence for dyads with obesity-obesity is associated with: 1) non-compliance with general health recommendations, 2) internal traits/factors (i.e., mothers' less health consciousness, mental strength), 3) external factors (i.e., lower health literacy, socioeconomic status). The association of obesity with lower adherence is a bias that may exist among medical students and originate from assumptions about prior health adherence and maternal traits, some disparaging in nature. Such bias has potential to contribute to healthcare disparities. Findings highlight the utility of qualitative methods to understand beliefs driving perceptions and design bias-reducing interventions to trainee needs.

Imaging Modalities for Head and Neck Cancer: Present and Future.

Several imaging modalities are utilized in the diagnosis, treatment, and surveillance of head and neck cancer. First-line imaging remains computed tomography (CT); however, MRI, PET with CT (PET/CT), and ultrasound are often used. In the last decade, several new imaging modalities have been developed that have the potential to improve early detection, modify treatment, decrease treatment morbidity, and augment surveillance. Among these, molecular imaging, lymph node mapping, and adjustments to endoscopic techniques are promising. The present review focuses on existing imaging, novel techniques, and the recent changes to imaging practices within the field.

Relationships between effective safety training, safety knowledge and personal protective equipment related behaviors among firefighters.

INTRODUCTION: Firefighter injuries and fatalities have been attributed to improper or ineffective use of personal protective equipment (PPE). Although studies have examined predictors of PPE to include situational, leadership, stressors and other psychosocial factors, research has not thoroughly examined the relationships between effective safety training administration, knowledge creation, and the influence of those factors on PPE use among firefighters. METHOD: This study aimed to assess those relationships by using structural equation modeling analysis. RESULTS: The model fit was good, and findings confirmed the hypothesized model and relationships, which included a positive, significant relationship between effective safety training and safety knowledge and positive, significant relationships between safety knowledge and PPE-related safety behavior outcomes, including the effective use of PASS devices, the correct use of SCBA and PPE during overhaul operations, and the correct use and inspection of PPE among firefighters in general. PRACTICAL APPLICATIONS: Findings support the importance of safety training in the fire service to bolster knowledge and correct PPE use.