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ATF4-histone 2-hydroxyisobutyrylation feedback loop drives sepsis-induced inflammation.

BACKGROUND AND PURPOSE: The role and mechanisms of lysine 2-hydroxyisobutyrylation (Khib) in the acute inflammatory phase of sepsis remain unclear. We investigated the function and underlying mechanisms of histone H4 lysine 5 2-hydroxyisobutyrylation (H4K5-hib) in sepsis-induced inflammation in vivo and in vitro. EXPERIMENTAL APPROACH: Acute sepsis was induced by caecal ligation and puncture (CLP) in mice, and inflammatory responses were modelled in lipopolysaccharide (LPS)-stimulated macrophages. CUT&Tag-seq was used to identify genomic targets associated with H4K5-hib and activating transcription factor 4 (ATF4). Immunofluorescence, Western blotting, qPCR, dual-luciferase assays, and ELISA were performed to investigate the underlying mechanisms. KEY RESULTS: H4K5-hib levels were increased in macrophages during the acute inflammatory phase of sepsis. LPS stimulation enhanced H4K5-hib enrichment at the ATF4 promoter, thereby promoting ATF4 transcription. Inhibition of EP300-mediated 2-hydroxyisobutyrylation or mutation of H4K5 abolished ATF4 activation. Increased H4K5-hib activated the ATF4/NLRP3 signalling axis, promoting inflammasome assembly and amplifying inflammatory responses. ATF4 directly bound to the EP300 promoter and enhanced its transcription, forming a positive feedback loop that further increased H4K5-hib levels. In CLP-induced sepsis, pharmacological inhibition of EP300 or ATF4 reduced H4K5-hib levels and suppressed NLRP3 inflammasome activation. CONCLUSION AND IMPLICATIONS: These findings reveal a previously unrecognized epigenetic mechanism underlying sepsis-induced inflammation and identify the EP300/ATF4/H4K5-hib positive feedback loop as a potential therapeutic target for sepsis.

Animals

Impact of real-time respiratory function monitoring on neonatal mask ventilation training: a multicentre simulation-based crossover study.

OBJECTIVE: To evaluate whether visibility of respiratory function monitor (RFM) feedback improves mask ventilation performance and influences subsequent ventilation performance during neonatal resuscitation training. DESIGN: multicentre randomised crossover simulation study. PARTICIPANTS: Healthcare professionals involved in neonatal resuscitation training across participating centres. INTERVENTION: Participants performed positive pressure ventilation (PPV) on both term and premature manikins under two conditions: with visible RFM feedback and with the display masked. The order of feedback visibility was randomised. Each participant completed ventilation assessments in both conditions. MAIN OUTCOME MEASURES: Primary outcomes were expired tidal volume (Vte) and mask leak (%). The proportion of breaths within the target Vte range (4-8 mL/kg) was calculated as a performance indicator. Secondary outcomes included variability in Vte and mask leak to assess ventilation stability between conditions. RESULTS: Visible RFM feedback was associated with lower mask leak and improved ventilation stability in the preterm manikin and with tidal volumes entering the target range in the term manikin. Participants initially ventilated with visible feedback maintained performance after feedback removal, suggesting a carry-over learning effect. CONCLUSION: In this multicentre crossover simulation study, visible RFM feedback was associated with changes in mask ventilation performance and evidence of a carry-over learning effect following feedback removal. Real-time visibility of respiratory parameters may strengthen neonatal resuscitation training.

Humans

Not just when, but how: An exploratory dual-control approach to video feedback in motor learning.

The present study provides exploratory evidence for a novel dual-control paradigm. It examines whether combining temporal over video feedback timing with learner-controlled interactive playback functions (pause, slow-motion, rewind) would enhance motor skill acquisition beyond temporal autonomy alone. Sixty-four novice adults were randomly assigned to one of four conditions: Full Control (self-controlled timing + interactive replay), Partial Control (self-controlled timing + non-interactive replay), Yoked Full Control (externally controlled timing + interactive replay), or Yoked Partial Control (externally controlled timing + non-interactive replay). Motor accuracy (Radial Error), movement consistency (Bivariate Variable Error), technical execution, and self-efficacy were assessed at pre-test, 24-h retention, and 72-h retention following two acquisition sessions on a dart-throwing task (120 trials total). The Full Control group demonstrated the greatest and most durable learning gains across all outcomes. The Group × Time interaction was significant across all dependent variables (η2ₚ ranging from 0.140 to 0.234), with Full Control demonstrating superior retention at both 24 and 72 h relative to other groups (though differences relative to Partial Control were more pronounced at 72-h retention). Critically, the Yoked Full Control group showed comparatively weaker outcomes despite access to the same interactive playback functions. These findings suggest that interactive video tools may be most useful when learners can regulate both when feedback is accessed and how it is inspected. Theoretical and practical implications for the design of learner-centered video feedback systems are discussed.

Humans

Webcam-Based Real-Time Visual Feedback During Baduanjin Practice in Older Adults: 6-Week Pilot Randomized Study.

BACKGROUND: Baduanjin qigong is a traditional mind-body exercise used to support balance and physical health in older adults. Age-related changes in proprioception may make accurate self-directed performance difficult without external guidance. OBJECTIVE: The aim of this study is to explore whether webcam-based real-time visual feedback delivered during supervised laboratory sessions was associated with differences in webcam-derived 2D pose discrepancy and movement consistency during Baduanjin practice in older adults. METHODS: A total of 31 older adults were enrolled, and 28 participants with complete analyzable records were included in this complete-case dataset (feedback group, n=14; nonfeedback group, n=14). All sessions were conducted face-to-face in a supervised motion-analysis laboratory. Weekly 2D pose-discrepancy values were analyzed using a linear mixed-effects model with fixed effects for group, categorical week, and the group-by-week interaction and a participant-specific random intercept. Joint- and movement-specific participant-level 6-week means were analyzed exploratorily using Welch independent-samples t tests. Holm correction was applied across 24 exploratory contrasts (6 week-specific, 8 joint-specific, and 10 movement-specific comparisons), and Hedges g and 95% CIs were reported. Participant-specific weekly slopes and within-participant variability were additionally examined to directly assess longitudinal error drift. RESULTS: The linear mixed-effects model showed no significant group-by-week interaction (Wald χ25=1.09; P=.96) and no significant overall week effect (Wald χ25=6.40; P=.27). Averaged across 6 weeks, the feedback group had an estimated mean 2D pose discrepancy 1.20° lower than the nonfeedback group (95% CI -2.38° to -0.02°; P=.046), although this marginal pilot finding was sensitive to an analytic approach. No week-specific contrast remained significant after Holm adjustment. Nominal right elbow, right shoulder, and right knee differences did not survive global Holm correction. Form 3 showed a lower mean discrepancy in the feedback group (mean difference -3.70°, 95% CI -5.86° to -1.54°; Hedges g=-1.30; unadjusted P=.002; Holm-adjusted P=.04). Direct analyses of participant-specific slopes and within-participant SDs did not support a significant between-group difference in longitudinal error drift. CONCLUSIONS: In this small exploratory pilot study conducted under supervised laboratory conditions, the 6-week trajectories did not differ significantly between groups. A marginally lower average 2D pose discrepancy was observed in the feedback group across the 6 weeks, but no individual week- or joint-specific comparison remained significant after multiplicity adjustment. Form 3 was the only exploratory contrast that remained significant after global Holm correction. Direct longitudinal analyses did not demonstrate prevention of error drift. Larger studies using validated reference measurements, prespecified outcomes, and adequately powered longitudinal designs are required.

Humans

Same-day initiation of tenofovir alafenamide-based pre-exposure prophylaxis with drug-level feedback for transgender women in Uganda.

OBJECTIVE: To evaluate the feasibility and acceptability of same-day initiation of emtricitabine/tenofovir alafenamide (F/TAF) pre-exposure prophylaxis (PrEP) and test the impact of drug-level feedback on PrEP adherence among transgender women (TGW) in Uganda. DESIGN: Randomized controlled trial. METHODS: HIV-negative TGW were randomly assigned 1 : 1 to intervention (drug-level feedback with tailored adherence counseling) or standard-of-care (SOC), and followed quarterly for 12 months (November 2021-July 2023; NCT04491422). Quarterly clinic visits included demographic and socio-behavioral data collection, PrEP refills, STI testing, and quarterly PrEP adherence assessment using tenofovir levels in dried blood spots (DBS; long-term) and urine (short-term). RESULTS: We enrolled 200 TGW (100 per arm), median age 21 years. Same-day F/TAF PrEP initiation was 100%. Tenofovir detection in urine (intervention arm) was 79, 80, 85, and 70% at the 3, 6, 9, and 12-month visits, respectively. Tenofovir detection in DBS was 46, 40, 35, and 31% at 3, 6, 9, and 12 months, respectively. Median tenofovir DBS concentrations were 40.6 and 47.0 fmol/punch in intervention and SOC arms, respectively. There was no intervention effect on PrEP adherence (DBS tenofovir levels) [adjusted incidence rate ratio (aIRR) 1.06; 95% CI: 0.82-1.37]. Never being harassed by police for being transgender (aIRR 1.66; 95% CI: 1.24-2.23), history of taking daily medication for more than 7 days (aIRR 1.51; 95% CI: 1.18-1.93) and higher monthly income (aIRR 1.44; 95% CI: 1.10-2.04) were associated with PrEP adherence. CONCLUSION: Oral F/TAF PrEP adherence among TGW in Uganda was low and not affected by drug-level feedback or tailored adherence counseling. Long-acting injectable PrEP formulations should be considered for this population.

Humans

A hybrid effectiveness-implementation trial to integrate precision skin cancer risk feedback in federally qualified health centers.

BACKGROUND: Skin cancers are the most common type of cancer in the United States, occur in all segments of the population, and are preventable. Our previous research with primary care patients' demonstrated interest in and efficacy of a precision prevention intervention providing feedback on MC1R risk level (higher versus average) in combination with prevention education materials relative to a standard educational intervention. Our current study is a hybrid type 1 effectiveness-implementation trial deployed at six federally-qualified health centers. This paper presents the study protocol. METHODS: A community advisory panel will guide development of study materials and measures. Staff training at each clinic will be completed in-person. Patients will be approached and screened in-person. Those completing genetic testing and the baseline survey will be randomized to the precision versus standard intervention for each risk level with a target sample size of 286 for each combination. Primary outcomes of effectiveness, assessed at 6 and 12 months, include a tanning score (5 items assessing intentional and unintentional tanning), number of sunburns, conduct of a skin self-examination, and electronic health record documentation of clinician-patient communication about skin cancer prevention. Effectiveness comparisons will focus on the precision relative to the standard intervention among higher risk participants. Implementation data will be collected to identify barriers and facilitators. RESULTS: Effectiveness and implementation outcomes will be evaluated following study completion. CONCLUSIONS: Results will guide subsequent scale-up of the precision intervention, including modifications of the intervention as well as methods for implementation. CLINICAL TRIALS IDENTIFIER: NCT07222995.

Humans

Smart crutch tipsTM real-time feedback improves adherence to partial weight-bearing protocols following lower extremity fracture surgery: a pilot study.

PURPOSE: To evaluate the effectiveness of Smart Crutch Tips&#x2122; in promoting adherence to prescribed early partial weight-bearing (PWB) protocols and to assess patient experience with real-time weight-bearing feedback during home rehabilitation. METHODS: Twenty patients with lower extremity fractures prescribed partial weight-bearing (PWB) were randomized into two groups utilizing real-time feedback crutch tips (RFC). The Intervention group (n&#x2009;=&#x2009;10) used Smart Crutch Tips&#x2122; (ComeBack Mobility Inc., Kiev, Ukraine), which provided real-time feedback on weight-bearing compliance. The Control group (n&#x2009;=&#x2009;10) also used crutches equipped with Smart Crutch Tips&#x2122;, but notifications were disabled, allowing passive data collection without patient feedback. Weight-bearing compliance was defined as the percentage of steps within &#xb1;&#x2009;10% of the prescribed target. Secondary outcomes included patient satisfaction and device usability assessed using the System Usability Scale (SUS) throughout the home rehabilitation period. RESULTS: The Intervention group demonstrated significantly greater PWB compliance compared with the Control group (73.6% vs. 21.1%, p&#x2009;<&#x2009;0.01). The Intervention group reported a mean SUS score of 84.25, indicating excellent usability. No device-related complications or adverse events were observed. Patient satisfaction, assessed through video interviews, was high, with participants in the Intervention group expressing a strong willingness to recommend the device to others with similar injuries and rating it 10 out of 10. CONCLUSION: Smart Crutch Tips&#x2122; significantly improved adherence to prescribed partial weight-bearing protocols following lower extremity fracture surgery. The RFC device demonstrated high usability, excellent patient satisfaction, and no device-related complications during home rehabilitation throughout the study period.

Humans

Disentangling oscillatory and aperiodic neural activity in autism: A spectral parameterization analysis of neurofeedback intervention.

BACKGROUND: Autism Spectrum Disorder (ASD) is characterized by atypical neural oscillations and heterogeneous alterations in excitation/inhibition (E/I) balance, the directionality of which varies across individuals, neural circuits, and developmental stages. While Alpha-band neurofeedback (NFB) is a promising intervention, its underlying neurophysiological mechanisms remain unclear, partly due to the conflation of periodic and aperiodic signals in traditional EEG analysis. METHODS: This randomized controlled trial recruited 40 children with ASD, assigned to either an experimental group (Alpha-training NFB) or a no-feedback group. Resting-state EEG and behavioral assessments (SRS, ABC) were collected pre- and post-intervention. We employed spectral parameterization to decompose neural activity into aperiodic (1/f slope, offset) and periodic (periodic alpha power, center frequency) components. RESULTS: NFB training yielded significant behavioral improvements in social cognition and relating skills. Physiologically, the experimental group exhibited a significant steepening of the aperiodic slope (increased exponent), reflecting a reduction in neural noise and potential optimization of inhibitory modulation. Furthermore, we observed enhanced periodic alpha power and an acceleration of the alpha center frequency (ACF), indicative of improved neural efficiency and maturation. These physiological shifts in frontal and occipital regions were significantly correlated with improvements in behavioral scores. CONCLUSION: Alpha-training NFB was associated with improvements in caregiver-rated behavioral scores and modulated spectral features of resting-state EEG in children with ASD. These findings validate the utility of spectral parameterization markers in evaluating neuromodulatory interventions.

Humans

How AI-supported intelligent systems support infection prevention and control training in healthcare: A systematic review of educational functions and outcomes.

AIMS: Artificial intelligence (AI)-supported intelligent systems have been increasingly incorporated into infection prevention and control (IPC) education and training, primarily to support the monitoring of observable behaviors and the provision of feedback. However, existing evidence has focused largely on short-term compliance outcomes, with limited synthesis of the educational role of AI-supported intelligent systems in supporting sustained IPC competence. This systematic review examined how AI-supported intelligent systems have been designed and used to support IPC education and training, with a focus on system characteristics, educational functions, and reported outcomes. DESIGN: A systematic literature search was conducted across the PubMed/MEDLINE, Embase, Cochrane, and CINAHL databases. DATA SOURCES: A total of 18 studies met the inclusion criteria. Findings were qualitatively synthesized according to system design characteristics, educational functions, and outcome domains. REVIEW METHODS: Methodological quality was appraised using the Mixed Methods Appraisal Tool. RESULTS: Most AI-supported intelligent systems focused on hand hygiene and relied on fully automated monitoring systems to capture behaviors and provide performance feedback. Educational functions were predominantly limited to performance assessment, automated feedback, and reminders. Outcomes were mainly measured using compliance or performance metrics, whereas sustained behavioral change and decision quality were rarely assessed. CONCLUSIONS: AI-supported intelligent systems have been used primarily to reinforce short-term IPC performance and compliance. However, their current applications for supporting sustained competence over time remain limited. The findings of this review suggest that AI-supported intelligent systems may serve as maintenance-oriented educational support by extending learning beyond initial instruction through repeated practice and feedback. Future research should prioritize outcome measures that capture the durability of performance and decision-making processes to better align AI-supported intelligent systems used in IPC education and training with the educational demands of clinical practice.

Humans

Improving Community-Based Care for Adolescents with ADHD: a Randomized Controlled Trial of Artificial Intelligence-Assisted Fidelity Supports.

Cognitive-behavioral treatments (CBTs) for adolescents with ADHD demonstrate promise of long-term effects on outcome. However, their implementation in routine care community clinics faces barriers that impact quantity, efficiency, and quality of delivery, as well as client outcomes. This study is a randomized controlled trial designed to evaluate the impact of an AI-assisted service delivery model on therapist implementation of Supporting Teens' Autonomy Daily (STAND), a CBT blended with Motivational Interviewing (MI) for adolescents with ADHD. Adolescents with ADHD (N&#x2009;=&#x2009;51), who were clients at three community mental health agencies, received treatment from 23 therapists. There was randomization of adolescents and therapists to AI-assisted or standard implementation supports. In addition to standard supports (i.e., training, standard facilitation resources, technical assistance, case supervision), AI-assisted support package included digitized facilitation resources housed in a clinical dashboard (Care4), feedback on content fidelity, and AI-generated feedback on MI implementation quality. The AI-assisted group was associated with more efficient treatment delivery and lower number of appointments attended by the adolescent. There was also a significant decrement in MI quality over time in the AI-assisted group compared to the standard support group. Feedback in focus groups indicated that therapists perceived a task-oriented mindset to be associated with receipt of the AI-assisted support package, leading therapists to prioritize efficiency over relational aspects of therapy. Following the results of this trial, a future, larger RCT should examine the impact of the AI-assisted implementation model on mental health outcomes and cost savings to organizations, third party payers, and clients. Trial registration number: NCT05135065; https://www.clinicaltrials.gov ; Registered September 2021.

Humans

Use of wearable technologies for physical activity promotion in older adults: A systematic review.

This systematic review, conducted according to PRISMA guidelines and registered in PROSPERO (CRD420251055299), examined the use of wearable technologies for promoting physical activity (PA) in adults aged 60 years and older. Searches across five databases (PubMed, Scopus, Web of Science, CINAHL, Cochrane) identified 2438 records, of which only six randomized controlled trials published between 2021 and 2025 met inclusion criteria, with sample sizes ranging from 36 to 551 participants and mean ages between 65 and 79 years. Given the small number of included studies, findings should be interpreted as preliminary. The studies ranged from the standalone use of commercial trackers (Fitbit, Polar, ActiGraph) to multicomponent interventions combining wearables with physiotherapist feedback, telephone counseling, web-based platforms, or interactive cognitive-motor training. Wearables used alone, as in the REACT trial, produced small or non-significant PA effects. In contrast, interventions integrating devices with personalized feedback, professional support, or digital platforms, such as PROMOTE and TASMANIA, were associated with more consistent improvements in PA, physical function, and cognitive outcomes. Multicomponent programs, such as PEER and ICMT, reported broader benefits, including cognition, balance, and reductions in sedentary behavior, though these findings derive from individual trials and require replication. Risk of bias, assessed with the Cochrane Risk of Bias tool version 2 (RoB 2.0), was rated as "some concerns" for five studies and low for only one, mainly due to gaps in randomization reporting, missing data, and lack of preregistration. Tentatively, and based on a very limited evidence base, wearables may have greater impact when embedded within broader behavioral systems, incorporating feedback, coaching, or interactive components, rather than when used in isolation as passive monitoring tools. Adherence and psychosocial outcomes appeared related to comfort and perceived usefulness among older adults, though larger and more robust trials are needed to confirm these patterns.

Humans

Effectiveness of an AI-based home exercise app for rehabilitation of rotator cuff-related shoulder pain: A randomized controlled trial.

BACKGROUND: Rotator cuff-related shoulder pain contributes to disability and healthcare use. Although therapeutic exercise is first-line treatment, limited supervision and adherence may reduce its effectiveness; digital rehabilitation with real-time feedback may address these limitations. OBJECTIVES: To evaluate the effectiveness of adding a digital rehabilitation program to standard physiotherapy on pain, function, fear-avoidance beliefs, and healthcare utilization. DESIGN: Single-center, assessor-blinded, randomized controlled trial with two parallel groups. METHOD: Forty-six adults (mean age 59 years) with rotator cuff-related shoulder pain were randomized to 12 weeks of conventional physiotherapy or physiotherapy plus an AI-based digital rehabilitation program using computer vision for real-time feedback and performance monitoring. Outcomes were assessed at baseline and at 2, 4, and 12 weeks. Pain intensity (NPRS) was primary outcome; secondary outcomes included upper limb function (QuickDASH), fear-avoidance beliefs (FABQ), and post-intervention healthcare utilization. Analyses followed an intention-to-treat approach. RESULTS: Pain reduction exceeded the MCID (1.3) at 4 and 12 weeks. Between-group differences favoured the intervention at Weeks 2 and 4 (MD -0.7; 95% CI -1.13 to -0.14 and MD -1.01; 95% CI -1.8 to -0.2, respectively). Upper limb function improved more at Week 4 (MD -7.3; 95% CI -12.3 to -2.2). FABQ scores decreased more at Week 12 (MD -7.6; 95% CI -14 to -0.5). Fewer participants in the experimental group required post-intervention healthcare (3 vs 10; p&#x202f;=&#x202f;0.02). CONCLUSION: Adding AI-based home exercise app to conventional treatment improve pain and may improve function and reduce healthcare utilization in rotator cuff-related shoulder pain.

Humans

Standardized visual overlays enhance laparoscopic instruction: A mixed-methods evaluation.

Effective communication during laparoscopic procedures is frequently undermined by spatial disorientation and inconsistent terminology between instructors and trainees. This study examined whether standardized visual overlays on endoscopic monitors could enhance communication and learning. We conducted a three-phase mixed-methods study: qualitative observation of 20 laparoscopic teaching cases; a randomized trial of 63 second-year medical students assigned to control, clock, or alphanumeric grid (AG) overlays during three trials of a standardized transfer task; and intraoperative implementation in 44 cases (30 AG, 14 clock) with post-case surveys and qualitative feedback. In simulation, the clock overlay produced the fastest completion times, whereas the AG yielded the lowest error scores, and both overlays outperformed the control. Intraoperatively, the AG was rated higher than the clock for communication clarity, spatial orientation, perceived operative efficiency, and trainee confidence. Standardized visual overlays, particularly the AG, appear to support intraoperative teaching by providing a shared spatial frame of reference.

Laparoscopy

Psychiatric mental health nurse practitioner outcomes after completion of a 1-year postgraduate fellowship.

Psychiatric mental health nurse practitioners (PMHNPs) are an essential and growing part of the health care workforce, especially in community settings. To address PMHNPs' increasing presence in community psychiatry, a 1-year postgraduate PMHNP fellowship in community psychiatry was developed with the goals of enhancing clinical competency and employment retention in underserved public sector settings. Data on 5 cohorts and 31 fellows are presented in this article. PMHNP fellows, preceptors, didactics, and clinical sites were evaluated across several time points including baseline and 6 and 12 months. The program has graduated 100% of fellows with largely positive feedback. Fellows reported significant improvements in competency across the domains of 1) assessment and diagnosis, 2) treatment, and 3) professionalism and leadership. These items were substantiated by clinical preceptors' ratings of fellows' clinical skills from 6-month and 12-month time points. Relatedly, clinical sites, preceptors, and didactics were all rated highly by fellows. After the program, 90.3% of graduates remained working in the public sector including correctional settings, community clinics, and safety net hospitals.

Community psychiatry

Review: The African turquoise killifish as a model for the integrative physiology of vertebrate aging.

With increasing emphasis on extending healthy lifespan, aging research requires vertebrate models that permit efficient mechanistic investigation and intervention testing within practical time and cost constraints. The African turquoise killifish (Nothobranchius furzeri) has attracted growing attention because it combines an exceptionally short life cycle with an intact vertebrate physiological context and an expanding genetic toolkit, enabling relatively rapid evaluation of candidate aging interventions and mechanistic analysis across molecular, tissue, and organismal levels. This review assesses N. furzeri from an integrative-physiology perspective, focusing on germline-soma interactions, gut microbiota-host crosstalk, nutrient sensing and metabolic remodeling, temperature responsiveness, and AMPK-mTOR-linked programs. It also examines expanding genome-engineering and reporter approaches that support mechanistic and tissue-resolved investigation of these physiological processes. Building on recent reviews of killifish biology, disease modeling, regeneration, and the hallmarks of aging, we synthesize evidence across major intervention domains, distinguish established phenotypic effects from incompletely resolved mechanisms, and highlight functional endpoints, methodological standardization, and the appropriate interpretation of the model's translational relevance. Together, these features position N. furzeri as a strategically useful vertebrate platform for rapid mechanistic testing, intervention evaluation, and prioritization of aging-related pathways. Future progress will require improved methodological standardization, tissue-resolved causal studies, and question-driven cross-species validation where appropriate.

Animals

Potential Links Between Physiological and Perceptual Strain in High Heat Stress.

The physiological strain index (PhSI) is widely used to quantify thermoregulatory and cardiovascular strain during heat stress. However, direct physiological measurements may not always be feasible in occupational or athletic settings. Therefore, this study aimed to examine the relationship and agreement between perceptual strain and integrated physiological strain indices during high heat stress. Ten healthy, physically active, non-heat-acclimated males (29 (7) yr; 1.79 (0.11) m; 77.4 (9.3) kg) completed two randomized crossover exercise trials in hot-dry (HD) and warm-humid (WH) environments with equivalent wet-bulb globe temperatures. Heart rate, rectal temperature, skin temperature, rating of perceived exertion, and thermal sensation were measured at baseline and every 15&#xa0;minutes during 60&#xa0;minutes of cycling. Physiological strain index (PhSI), adaptive physiological strain index (aPhSI), and perceptual strain index (PeSI) were calculated using validated equations. Repeated-measures correlation analyses demonstrated very strong associations between PeSI and both PhSI and aPhSI under HD (Rrm&#xa0;=&#xa0;0.940-0.943) and WH (Rrm&#xa0;=&#xa0;0.980-0.982; all p&#xa0;<&#xa0;0.001). Receiver operating characteristic analyses demonstrated good-to-excellent discrimination of physiological strain by PeSI (AUC&#xa0;=&#xa0;0.895-0.969). Mixed-effects analyses showed that higher PeSI values were associated with increased PhSI (&#x3b2;&#xa0;=&#xa0;1.325, p&#xa0;<&#xa0;0.001) and aPhSI (&#x3b2;&#xa0;=&#xa0;1.459, p&#xa0;<&#xa0;0.001). However, Bland-Altman analyses demonstrated relatively small mean biases (0.4-0.9 AU) but wide limits of agreement (-2.8 to 4.2 AU), indicating that PeSI and physiological strain indices are not interchangeable. These findings suggest that PeSI may serve as a practical adjunctive or screening indicator of physiological strain when direct physiological measurements are unavailable.

Humans

Physiologic age modifies the association between visceral fat predominance and urinary calcium excretion in adults with nephrolithiasis.

Although adiposity is associated with kidney stone disease, the relationship between abdominal fat distribution and urinary calcium excretion remains unclear. We investigated whether the CT-derived visceral-to-subcutaneous fat ratio (VSR) was associated with 24-hour urinary calcium excretion and whether physiologic age modified this association. This retrospective cross-sectional study included 308 adults with nephrolithiasis who underwent preoperative CT, stone removal, and postoperative metabolic evaluation. Participants were stratified into prespecified younger (men aged&#x2009;<&#x2009;50 years and premenopausal women) and older (men aged&#x2009;&#x2265;&#x2009;50 years and postmenopausal women) physiologic-age groups. Multivariable linear regression assessed the association between VSR and urinary calcium excretion and its modification by physiologic age. Results showed that VSR was not associated with urinary calcium excretion in the overall cohort, but its association differed significantly by physiologic age (P for interaction&#x2009;<&#x2009;0.001). Among younger participants, each 1-unit higher VSR was associated with 2.07 mmol/day greater urinary calcium excretion (95% CI, 1.23-2.90), whereas no significant association was observed in the older group. These findings suggest that the metabolic relevance of visceral fat predominance differs by physiologic age, with a significant association observed only in younger adults. Prospective studies are needed to confirm these findings and determine their clinical implications.

Humans