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Physiological Reports

Wiley

Preprints posted in the last 7 days, ranked by how well they match Physiological Reports's content profile, based on 40 papers previously published here. The average preprint has a 0.04% match score for this journal, so anything above that is already an above-average fit.

1
Effect of Match-Play Fatigue on Muscle Stiffness and Explosive Force Asymmetries in Soccer Players Post-Anterior Cruciate Ligament Reconstruction

Bari, M. H.; Bhalli, A. Z.; Sattar, H.

2026-07-21 sports medicine 10.64898/2026.07.18.26357476 medRxiv
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ABSTRACT Background: Athletes who return to soccer after anterior cruciate ligament reconstruction (ACLR) remain at elevated risk of secondary injury despite meeting conventional discharge criteria, and neuromuscular deficits in the reconstructed limb are known to be exposed by fatigue. Objective: To determine whether match-play fatigue differentially affects muscle stiffness, countermovement jump (CMJ) force symmetry, and rate of force development (RFD) asymmetry between soccer players with a history of ACLR and uninjured teammates. Methods: A prospective, cross-sectional, matched-control study enrolled 128 competitive soccer players (64 ACLR, 6-22 months post-surgery; 64 uninjured controls) across five recruitment waves (February-June 2026). Bilateral CMJ peak vertical force, jump height, RFD, and myotonometric stiffness of the rectus femoris (RF), vastus medialis (VM), and biceps femoris (BF) were recorded immediately before and after a standardized competitive match. Fatigue was quantified from second-half heart rate (percentage of age-predicted maximum) and end-match rating of perceived exertion (RPE). Within-group pre-to-post changes were evaluated with paired t-tests, between-group differences in the magnitude of change with independent-samples t-tests, and associations between fatigue indices and asymmetry changes with Pearson correlations. Results: Match play reduced CMJ limb symmetry index (LSI) in both groups, but the decline was more than three-fold greater in the ACLR group, 92.6% (SD 5.4%) to 85.1% (SD 7.1%), than in control group, 97.3% (SD 3.9%) to 95.0% (SD 4.2%), group-by-time difference, p < 0.001, (d = 0.64). RFD asymmetry approximately doubled in the ACLR group, 10.6% (SD 4.1%) to 17.6% (SD 6.5%), compared with a smaller rise in control group, 4.6% (SD 2.4%) to 6.3% (SD 3.7%); p < 0.001, d = 0.77). Involved-limb stiffness losses in the ACLR group exceeded those of controls for the RF (-21.2 vs. -9.2 N/m, p < 0.001), VM (-17.7 vs. -6.1 N/m, p < 0.001), and BF (-13.3 vs. -6.6 N/m, p < 0.001), whereas uninvolved-limb stiffness losses did not differ between groups (all p > 0.05). Fatigue markers (heart rate, RPE) were not significantly correlated with the magnitude of individual asymmetry change (|r| [&le;] 0.18, p > 0.15). Conclusions: In competitive soccer players 6-22 months after ACLR, match-play fatigue selectively compromises stiffness and explosive force output of the reconstructed limb, widening inter-limb asymmetries beyond what is seen in uninjured teammates, even though global cardiovascular and perceptual fatigue were comparable between groups. These findings suggest that return-to-sport testing performed only in a rested state may underestimate residual neuromuscular deficits, and support fatigue-inclusive assessment protocols before athletes are cleared for unrestricted competition. Abbreviations: ACL: anterior cruciate ligament, ACLR: anterior cruciate ligament reconstruction, BF: biceps femoris, CMJ: countermovement jump, HRmax: maximum heart rate, LSI: limb symmetry index, RF: rectus femoris, RFD: rate of force development, RPE: rating of perceived exertion, RTS: return to sport, VM: vastus medialis, SD: standard deviation. Keywords: Anterior cruciate ligament reconstruction, muscle fatigue, muscle stiffness, countermovement jump, limb symmetry index, rate of force development, soccer, return to sport.

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Switching from febuxostat to dotinurad in patients with chronic kidney disease and hyperuricemia: a single-center, non-randomized study

Irifuku, T.; Kashiwado, S.; Masaki, T.

2026-07-18 nephrology 10.64898/2026.07.16.26358294 medRxiv
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Recently, an observational study demonstrated that a lower fractional excretion of uric acid (FEUA) is significantly associated with a higher risk of kidney failure. This study aimed to assess the efficacy of switching from febuxostat to dotinurad, which increases FEUA, in patients with chronic kidney disease (CKD) and hyperuricemia (HUA).This was a non-randomized, open-label, single-center, prospective, single-arm study involving 60 patients with CKD and HUA who received febuxostat. Participants first underwent a 3-month observation period, followed by a 3-month intervention period, during which treatment was switched from febuxostat to dotinurad. The primary outcomes were changes from baseline to 3-months after switching in the estimated glomerular filtration rate (eGFR) calculated from serum creatinine (eGFRcreat) and serum cystatin C (eGFRcys), as well as the serum uric acid levels. The secondary outcome was defined as the correlation between{Delta}FEUA and the changes in both eGFRcreat({Delta}eGFRcreat) and eGFRcys({Delta}eGFRcys), respectively. During the observation period, mean eGFRcreat decreased significantly. The baseline eGFRcreat (mL/min/1.73 m{superscript 2}) was 36.0 {+/-} 15.2, and the serum urate level (mg/dL) was 5.5 {+/-} 1.2. During the intervention period, eGFRcreat increased in contrast to the significant decline observed in eGFRcys. After 3 months of switching to dotinurad, the mean serum UA levels increased significantly from 5.5 {+/-} 1.2 to 6.1 {+/-} 1.4 mg/dL, despite a significant elevation in FEUA. Both {Delta}eGFRcreat and {Delta}eGFRcys after switching to dotinurad were positively correlated with {Delta}FEUA. Switching from febuxostat to dotinurad resulted in discrepant changes in eGFRcreat and eGFRcys, suggesting that renal function should be assessed carefully after switch. Additionally, the risk of elevated serum UA levels should be considered when switching from febuxostat to dotinurad in patients with CKD.

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From Real-World Data to Virtual Intervention: A Probabilistic Neural Network for Simulating Kidney Function Preservation via Proteinuria Reduction

Takeda, A.; Igata, H.; Mizuno, K.; Yano, Y.; Nagasu, H.; Ohashi, M.; Kashihara, N.; Kobayashi, H.

2026-07-15 nephrology 10.64898/2026.07.12.26357786 medRxiv
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Predicting the long-term kidney function decline is critical for timely intervention but remains challenging. While the urinary protein-to-creatinine ratio (uPCR) is a potential surrogate endpoint, its short-term reduction's link to long-term nephroprotection requires investigation. This study aimed to develop a probabilistic neural network model to capture both the estimated glomerular filtration rate (eGFR) slope and its uncertainty based on baseline clinical characteristics. Using a retrospective dataset, we designed a neural network to output a predictive distribution (mean and standard deviation {sigma}) for the eGFR slope. SHAP (SHapley Additive exPlanations) was used for model interpretation, and a simulation study quantified the impact of uPCR reduction. In the validation set, the model achieved a Pearson's correlation coefficient of 0.56 and an RMSE of 2.81 ml/min/1.73m^2/year between predicted and actual slopes. SHAP analysis identified uPCR as the most potent predictor, with higher baseline levels associated with a more rapid eGFR decline. Furthermore, a simulated 62% uPCR reduction demonstrated a significant improvement in the predicted eGFR slope, an effect most pronounced in patients with high baseline uPCR. This proof-of-concept study reinforces the critical role of uPCR in predicting eGFR slope and suggests its reduction may contribute to long-term kidney function preservation, warranting validation in larger, diverse real-world datasets.

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Microvascular Thrombosis and Acute Kidney Injury in COVID-19: A Systematic Review and Quantitative Analysis

Duarte, C. A.; Uscocovich, V. S. M.; Misael, I.; Duarte, P. D. A. C.; Sestito, E. B.; Da SIlva, P. N.

2026-07-17 nephrology 10.64898/2026.07.14.26357748 medRxiv
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Abstract Objective: To synthesize the available evidence on the association between SARS-CoV-2-related microvascular thrombosis and acute kidney injury (AKI), with emphasis on renal outcomes, mortality, and renal replacement therapy requirements. Methods: This systematic review followed the PRISMA 2020 statement and was prospectively registered in PROSPERO (CRD420251132701). PubMed/MEDLINE, Scopus, and Embase were searched for systematic reviews, including meta-analyses, and umbrella reviews investigating the association between SARS-CoV-2-related microvascular thrombosis and acute kidney injury. Two reviewers independently performed study selection, data extraction, and methodological quality assessment using AMSTAR-2 and ROBIS. Evidence was synthesized through a structured narrative synthesis supported by quantitative data extracted from the included reviews. Results: Six evidence syntheses evaluating kidney involvement, thrombotic events, and microvascular mechanisms in COVID-19 were included. AKI incidence was 9.2% (95%CI 4.6-13.9) among hospitalized patients and 32.6% (95%CI 8.5-56.6) among critically ill patients. In children with multisystem inflammatory syndrome associated with SARS-CoV-2, AKI incidence was 20% (95%CI 14-28). Microvascular or thrombotic events were associated with adverse renal outcomes (OR 2.14; 95%CI 1.32-3.48). AKI was associated with increased mortality (OR 4.68; 95%CI 1.06-20.70) and greater likelihood of renal replacement therapy requirement (OR 2.87; 95%CI 1.45-5.68). The certainty of evidence ranged from moderate to high for the principal outcomes. Conclusion: Current evidence supports an important association between microvascular thrombotic injury and COVID-19-associated AKI. These findings reinforce the relevance of endothelial dysfunction and thromboinflammatory pathways in kidney involvement during COVID-19 and highlight the need for early renal monitoring, risk stratification, and kidney-protective strategies in high-risk patients. Keywords: COVID-19; Acute Kidney Injury; Microvascular Thrombosis; SARS-CoV-2; Renal Replacement Therapy; Systematic Review

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Validity and Test-Retest Reliability of the Hume Pod Bioimpedance Analyzer for Body Composition Assessment

Tinsley, G. M.; Velasquez, C. M.; Florez, C. M.; Way, A. E.; Sullivan, M. H.; Whitson, J. A.; Rudolph, R. A.; Alexander, J. R.; Malladi, A.

2026-07-20 nutrition 10.64898/2026.07.17.26358337 medRxiv
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Consumer-grade bioelectrical impedance analyzers have become widely used for body composition assessment, yet their accuracy varies considerably across devices. The Hume Pod is a popular consumer-grade analyzer marketed as being highly accurate, but independent validation is lacking. The purpose of this study was to evaluate the reliability and validity of the Hume Pod relative to both a four-compartment (4C) model and dual-energy X-ray absorptiometry (DXA). Sixty-seven adults (42 females, 25 males; age 37.2 +/- 13.5 years, body mass index: 24.6 +/- 4.9 kg/m2, body fat percentage [BF%]: 26.4 +/- 10.2%) completed duplicate Hume Pod assessments alongside DXA and 4C evaluations. Reliability was evaluated using the technical error of measurement (TEM) and intraclass correlation coefficients (ICC). Validity was assessed using equivalence testing, Lin's concordance correlation coefficient (CCC), standard error of the estimate (SEE), Bland-Altman analysis, and additional tests. The Hume Pod demonstrated strong reliability, with ICCs >/= 0.993 and TEMs of 0.8% for BF% and 0.6 kg for fat mass (FM) and fat-free mass (FFM). Relative to the 4C model, BF%, FM, and FFM estimates were statistically equivalent (all p<0.05), with strong agreement (CCC=0.95-0.98), low SEE values (3.1%, 2.3 kg, and 2.2 kg, respectively), moderate limits of agreement (+/-6.1%, +/-4.5 kg, and +/-4.5 kg), and no proportional bias. Compared with DXA, generally strong agreement was also observed. These findings indicate that the Hume Pod demonstrates strong reliability and validity compared with laboratory reference methods for body composition estimation, supporting its potential use as a consumer body composition assessment.

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Accuracy of a Smart-Ring VO2max Estimate and Five Published Prediction Equations Against Cardiopulmonary Exercise Testing: Development and Validation Study With Population-Scale Analysis

Dhawale, N.; Mukundan, S.; Agarwal, A.; Mondal, D.; Shanmugam, A.; Kumar, P.; Mittal, M.; Narasimhan, V.

2026-07-17 sports medicine 10.64898/2026.07.16.26358226 medRxiv
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Background. Maximal oxygen uptake (VO2max) is a leading marker of cardiorespiratory fitness and a strong predictor of all-cause mortality. Cardiopulmonary exercise testing (CPET) is the reference method but is resource-intensive, so consumer wearables estimate VO2max from passively collected signals; these estimates compress the fitness range, returning near-correct group averages while ranking individuals poorly. No peer-reviewed validation of a smart-ring VO2max estimate against CPET has been reported, and none in a South Asian cohort. Objective. To validate the Ultrahuman Ring AIR VO2max estimate against laboratory CPET, benchmark it against published prediction equations, and assess its generalization and construct validity. Methods. In a single-site paired ring-CPET cohort (N = 101; mean CPET peak VO2 43.3 mL{middle dot}kg-{superscript 1}{middle dot}min-{superscript 1}, SD 9.9), peak oxygen uptake was measured by treadmill or cycle-ergometer CPET, and the Ultrahuman Ring AIR estimate was computed from passively collected signals using a transparent ensemble based on published equations. Ensemble weights and calibration were selected on an 85-subject development set by an automated search minimizing a composite 5-fold cross-validated error criterion; the locked estimate was evaluated on a 16-subject held-out test set. The calibrated coefficients are proprietary. Agreement was quantified with mean absolute error (MAE), bias, Pearson r, regression slope and Lin's concordance correlation coefficient (CCC; bootstrap 95% CIs), and Bland-Altman limits of agreement. Separately, in 181,133 de-identified Ring users (no CPET reference), construct validity was assessed against ring-measured sleep, continuous glucose monitoring (n = 2,597), and a venous blood panel (n up to 15,203), adjusted for age, sex, and BMI, with lipoprotein(a) as a pre-specified negative control. Reporting followed TRIPOD and STARD. Results. With a self-reported fitness level provided, the estimate agreed with CPET peak VO2 at MAE 4.68 mL{middle dot}kg-{superscript 1}{middle dot}min-{superscript 1} (95% CI 3.93 to 5.49), Pearson r 0.79, CCC 0.79, and slope 0.71. The five published equations were worse on every metric (MAE 6.2 to 10.6, CCC 0.28 to 0.56, slope 0.32 to 0.42), each compressing the fitness range. On the held-out test set (n = 16), agreement held (r 0.84, slope 0.81, MAE essentially unchanged). Without the fitness input, full-cohort MAE was 5.16, still ahead of every published equation. At population scale, higher estimated fitness tracked a healthier profile on measurements the estimate does not use: better ring-measured sleep; higher continuous-glucose time in target range (79.6% versus 61.5%, top versus bottom decile; n = 222 and 399 of 2,597 users); and lower triglycerides, fasting glucose, and HOMA-IR (n up to 15,203 assayed per marker). These associations held after adjustment for age, sex, and BMI, whereas the pre-specified negative control lipoprotein(a) did not separate the deciles. Conclusions. The Ultrahuman Ring AIR VO2max estimate agreed with laboratory CPET substantially better than published prediction equations, held its agreement on held-out subjects, and ordered a large population along independent cardiometabolic gradients consistent with true fitness.

7
Early Feasibility of NIVA Score Decongestion Responsiveness: A Pilot Clinical and Preclinical Study

Alvis, B. D.; Schmeckpeper, J.; Rali, A. S.; Huston, J.; Tsai, S.; Amancherla, K.; Armstrong, D.; Gupta, R.; Whitfield, J. S.; Harder, R.; Miller, K.; Horne, M.; Wervey, D.; Pein, R.; Isanaka, T.; Case, M.; Wise, E.; Perrien, B.; Brophy, C.; Lindenfeld, J.; Hocking, K.

2026-07-15 cardiovascular medicine 10.64898/2026.07.13.26357910 medRxiv
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Residual congestion is the principal driver of heart failure readmission, and reliable serial assessment of volume status remains an unmet clinical need. This study asked whether a wrist-worn, machine-learning-based device for non-invasive venous waveform analysis in heart failure (the NIVAHF device), which produces an integer-scaled estimate of pulmonary capillary wedge pressure termed the NIVA Score, responds to acute changes in volume status. Agreement between the NIVA Score and invasively measured pulmonary capillary wedge pressure at single time points has been established in a separate prospective, multi-site study; however, such static agreement does not establish whether the measure tracks dynamic decongestion. We therefore evaluated the directional responsiveness of the locked NIVA Score in two prespecified cohorts: hospitalized adults with acute decompensated heart failure undergoing routine intravenous diuresis, and a controlled porcine model of volume overload followed by diuresis. In eleven patients contributing thirteen paired measurements (mean net fluid balance -2.1 {+/-} 1.0 L), NIVA Scores decreased significantly after diuresis (paired t-test, P = 0.04). In five pigs contributing twenty-four paired measurements, NIVA Scores decreased significantly after intravenous furosemide following crystalloid loading (P < 0.01), and the direction of change was concordant with measured urine output in every animal. Statistical significance was reached in both cohorts despite modest sample sizes, indicating a measurable NIVA Score reduction with volume removal. In an exploratory analysis, the discharge NIVA Score yielded an area under the receiver-operating-characteristic curve of 0.85 (95% confidence interval 0.575-1.00; P = 0.04) for thirty-day readmission. Together, the significant, directionally concordant NIVA Score reductions across independent clinical and preclinical cohorts demonstrate that the device tracks acute decongestion and support its use for serial, non-invasive congestion monitoring; an adequately powered prospective study is the planned next step.

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Data-driven calibration of low-cost wearable motion trackers for gait and dynamic stability measurement

He, Y.; Dong, Y.; Brodie, M. A.; Kim, J.; Lord, S. R.; Okubo, Y.

2026-07-15 sports medicine 10.64898/2026.07.13.26357919 medRxiv
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Low cost inside out wearable trackers can be deployed at scale to measure body motion, but errors in estimated sensor position propagate through coordinate transformations into derived gait and dynamic-stability metrics. Healthy adults walked on a treadmill at 0.5 to 2.0 m/s while VIVE Ultimate Tracker (VUT) and Vicon data were recorded. Data-driven calibration models were developed to correct tracker coordinates and to estimate full body centre of mass (CoM) from a sacrum-only configuration. Agreement with Vicon was assessed using RMSE, mixed-effects Bland-Altman limits of agreement, MAE, and intraclass correlation coefficients. Calibration improved coordinate-level agreement. For gait parameters, model-corrected VUT showed small errors against Vicon (MAE: 0.24 to 0.71 mm step height, 1.73 to 4.63 mm step length, 0.15 to 0.95 mm step width, 0.26 to 0.88 mm foot clearance). Proxy CoM-derived margin of stability (MoS) agreed excellently with Vicon. For the sacrum-only pipeline, calibration reduced CoM RMSE from 103.65 to 104.04 mm to 7.55 to 8.95 mm, and markedly reduced systematic error in stability outcomes, with extrapolated CoM bias decreasing from 172.92 to 0.29 mm and MoS bias from -75.09 to -3.54 mm. Data-driven calibration improved the measurement utility of low-cost VUTs, enabling inexpensive, relatively simple gait and stability measurement from a sacrum-only setup in controlled settings.

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Transient Apical Sparing in Hypertensive Heart Disease Explained by Laplace's Law

Hwang, I.-C.; Kim, H. M.; Jang, Y.; Bak, M.; Park, J.; Jeon, J.; Lee, S.-A.; Choi, H.-M.; Yoon, Y. E.; Cho, G.-Y.

2026-07-19 cardiovascular medicine 10.64898/2026.07.16.26358114 medRxiv
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Background: Apical sparing of left ventricular longitudinal strain (LS) is an echocardiographic clue to cardiac amyloidosis but may also occur in hypertensive heart disease (HHD). Objectives: To determine whether apical sparing in HHD is associated with regional left ventricular wall stress estimated according to Laplace's law. Methods: We retrospectively studied 1,559 patients with HHD, 47 with light-chain cardiac amyloidosis (ALCA), and 409 normotensive controls. Artificial intelligence-assisted echocardiography quantified segmental LS, wall thickness, and cavity radius at the basal, midventricular, and apical levels. Wall stress was estimated as mean blood pressure (MBP) x radius/(2 x wall thickness). Apical sparing was defined as a relative regional strain ratio (RRSR)[&ge;]1.0. Results: Apical sparing was present in 14 patients with HHD (0.9%), 13 with ALCA (27.7%), and no controls. Among HHD patients with apical sparing, RRSR decreased from 1.11{+/-}0.13 to 0.72{+/-}0.10 after antihypertensive treatment (P<0.001), accompanied by reduced wall stress and improved basal and midventricular LS, with resolution of apical sparing in all 14 patients. In the overall HHD cohort, changes in MBP and left ventricular mass index were independently associated with changes in RRSR. In an exploratory analysis of HHD patients with apical sparing, a reduction in basal wall stress was associated with a reduction in RRSR ({beta}=0.267 for {bigtriangleup}RRSRx100, 95% CI 0.023-0.511; P=0.036). In ALCA, favorable hematologic response was the only determinant of RRSR reduction. Conclusions: Apical sparing in HHD was uncommon but reversible and may represent a load-sensitive deformation pattern associated with regional wall stress, consistent with Laplace's law.

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A study of PROGRESS: the Therapeutic Potential of 17 OHPC on the Pathophysiology of Severe Preeclampsia

Brewerton, C. H.; Chambers, C. L.; Belk, S.; Wallace, K.; Roseburg, M.; Campbell, N.; Neeley, Y.; Dodd, C.; Morris, r.; Novotny, S.; Tucker, J. M.; LaMarca, B. B.; Amaral, L. M.

2026-07-17 obstetrics and gynecology 10.64898/2026.07.15.26358196 medRxiv
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Preeclampsia (PE), new onset hypertension after 20 weeks of gestation, affects 10% of all pregnancies in the U.S. and it is associated with progesterone deficiency, chronic inflammation, elevated angiotensin II type 1 receptor agonistic autoantibody (AT1-AA) and endothelial dysfunction. Progesterone, through its receptors, stimulates an anti- inflammatory protein called Progesterone Induced Blocking Factor (PIBF) which decreases during various pregnancy disorders. Therefore, this study was designed to test the hypothesis that a progestogen, in the form of 17-hydroxyprogesterone caproate, stimulates PIBF, lowers vasoactive mechanisms which reduces maternal blood pressure in women with early-onset preeclampsia (EOPE). PE women received 17-OHPC (250 mg, I.M.) and blood draws were collected before and after 17-OHPC supplementation. Placentas were collected at the delivery. 17-OHPC prolonged time of delivery beyond 72h on average and maternal blood pressure was significantly decreased in PE+17- OHPC. Progesterone and PIBF levels were reduced in PE group vs. NP group. Importantly, 17-OHPC increased PIBF and decreased vasoactive mechanisms and markers of inflammation. In conclusion, 17-OHPC or progesterone supplementation improves maternal outcomes in response to EOPE without causing further harm to the fetus.

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Intravesical Lactobacillus rhamnosus GG reduces symptoms among people with spinal cord injury and disease who use intermittent catheterization: A randomized comparison of two- and four-dose regimens.

Groah, S. L.; Tractenberg, R. E.; Riegner, C. R.; Forster, C. S.

2026-07-20 urology 10.64898/2026.07.17.26358333 medRxiv
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Background: Urinary tract infection (UTI) is the most common secondary condition among people with spinal cord injury/disease (SCI/D). Intravesical Lacticaseibacillus rhamnosus GG (LGG) is an antibiotic-sparing approach to managing urinary symptoms. Objective: Determine the optimal number of doses of intravesical LGG for urinary symptom reduction. Design: Prospective, randomized, two-arm dosing trial. Setting: National recruitment with a local subsample providing urine samples in Washington, DC, USA. Participants: Adults with SCI/D and neurogenic lower urinary tract dysfunction (NLUTD) who use intermittent catheterization (IC); 177 enrolled and randomized (intention-to-treat), with 76 compliant instillers (39 low-dose, 37 high-dose) in the per-protocol analytic sample. Interventions: Two (2 doses/24 hours) or four (4 doses/36 hours) intravesical LGG regimens, self-initiated in response to cloudier or malodorous urine per the Self-Management Protocol using Probiotics (SMP-Pro). Main Outcome Measures: Primary: proportion achieving [&ge;]20% reduction on the Urinary Symptom Questionnaire for Neurogenic Bladder-Intermittent Catheter version (USQNB-IC). Secondary: urinary biomarkers (leukocyte esterase, nitrite, white blood cells, urinary neutrophil gelatinase-associated lipocalin [uNGAL]) and standard urine culture (SUC) in a local subsample. Results: By Day 2, 57.9% (63.8% low-dose; 51.2% high-dose) achieved [&ge;]20% total symptom reduction; high-dose success rose to 70.0% by Day 4. Thirty percent of high-dose participants did not respond at either time point and could not be distinguished from responders by demographics or urine biomarkers. Urinary biomarkers and SUC were unchanged pre- to post-instillation. No serious adverse events were adjudicated as attributable to intravesical LGG by an independent Data Safety Monitoring Board (DSMB). Conclusions: A two-dose course of intravesical LGG yields clinically meaningful symptom improvement in the majority of people with SCI/D and NLUTD who use IC; four doses benefits a meaningful subgroup of two-day non-responders, while a small cohort remains nonresponsive. These results provide preliminary dosing guidance and support progression to a definitive trial.

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Analytical Performance and 99th Percentile Upper Reference Limit of the Novel SPINCHIP High-Sensitivity Cardiac Troponin I Point-of-Care Assay

MacKenzie, J.; Aakre, K. M.; Paus, D.; Broughton, M. N.; Storvold, G. L.; Olberg, A.; Stenmark, S.; Booij, B. B.; Scott, S.; Michel-Busseret, S.; Octave, L.; Tveit, A.; Lyngbakken, M. N.; Nilsson, J.; Rosjo, H.

2026-07-20 emergency medicine 10.64898/2026.07.17.26357157 medRxiv
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BACKGROUND In line with International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) recommendations for high-sensitivity cardiac troponin assays, analytical validation and reference limit assessments are required to confirm that an assay meets performance criteria. This study evaluated the analytical performance and established the 99th percentile upper reference limit (URL) for the SPINCHIP High-Sensitivity Cardiac Troponin I (SPINCHIP hs-cTnI) point-of-care assay. METHODS Analytical performance characteristics, including the limit of blank (LoB), limit of detection (LoD), and limit of quantification (LoQ), were assessed. Additionally, 1,053 plasma samples and 1,055 whole-blood samples were used to determine the URL. Imprecision around the 99th percentile URL was evaluated as part of the analytical validation. High-sensitivity criteria were assessed by confirming measurable cTnI in [&ge;]50% of healthy individuals (n=432 plasma; n=431 whole blood) and achieving imprecision <10% at the 99th percentile (plasma, n=960; whole blood, n=480). RESULTS SPINCHIP hs-cTnI demonstrated a LoB of 0.3 ng/L; LoDs of 0.8 ng/L (plasma) and 0.9 ng/L (whole blood); and LoQs of 1.1 ng/L (plasma) and 1.4 ng/L (whole blood). The analytical measuring range was 1.1-9,000 ng/L. Imprecision at the common 99th percentile URL (14 ng/L) was 5.8%; for men (URL=16 ng/L) 5.6% and for women (URL=10 ng/L) 6.3%. Greater than 85.2% (94.0% and 76.1% in men and women, respectively) of healthy individuals showed measurable cTnI above the LoD. CONCLUSIONS The SPINCHIP hs-cTnI assay meets the IFCC high-sensitivity requirements, demonstrating <10% imprecision at the 99th percentile, reliable low-concentration precision and cTnI detection in more than half of healthy individuals.

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Multi-Agent Dynamic Refinement Outperforms Static RAG in Clinical Reasoning for Complex Nephrology Cases

Yano, Y.; Kakizaki, H.; Nagasu, H.; Kishi, S.; Koshida, T.; Nihei, Y.; Hirano, A.; Sugawara, Y.; Imaizumi, T.; Osakabe, Y.; Sakaguchi, Y.; Nangaku, M.; Mori, H.; Naito, T.; Ohashi, M.; Maruyama, S.; Matsui, I.; Isaka, Y.; Okada, H.; Suzuki, Y.; Kashihara, N.

2026-07-16 nephrology 10.64898/2026.07.15.26358121 medRxiv
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Background: Large language models (LLMs) struggle with dynamic, longitudinal clinical reasoning. We developed a Multi-Stage Iterative Clinical Reasoning Agent framework to address this gap and systematically decouple the clinical efficacy of static retrieval-augmented generation (RAG) from dynamic self-refinement. Methods: Ten complex longitudinal nephrology cases, rigorously selected via a modified Delphi consensus technique, were blindly evaluated by four board-certified nephrologists and a multi-model AI panel. We compared three architectures across nine cognitive steps: (Model A) a baseline frontier LLM, (Model B) an LLM augmented with static guideline-based RAG, and (Model C) our proposed multi-agent framework featuring RAG integrated with iterative self-critique and refinement. Results: In human evaluations (20-point scale), Model C (mean 17.2, SD 1.2) significantly outperformed both Model A (16.1, 1.3) and Model B (16.2, 1.2) (P < 0.001). Implementing static RAG (Model B) yielded no significant improvement over the baseline. Automated AI evaluations (15-point scale) corroborated these findings: Model C (14.7, 0.6) outscored Model A (14.2, 0.9, P < 0.001) and Model B (14.3, 0.9, P = 0.01). While monolithic models exhibited severe score degradations in planning-heavy tasks such as dynamic differential diagnoses, the multi-agent framework effectively intercepted error cascades, achieving significantly higher diagnostic accuracy (mean 17.6, P = 0.019) and therapeutic management scores (17.3, P = 0.002). Conclusions: Static knowledge retrieval alone fails to enhance frontier LLM performance in longitudinal medical reasoning. Distributing clinical workflows into a multi-agent dynamic refinement pipeline significantly improves reasoning completeness, intercepts error cascades, and safely resolves planning bottlenecks in complex patient care.

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Comparing measured and calculated blood loss after a caesarean birth

Mansukhani, R.; Arribas, M.; Bello, N.; Chaudhri, R.; Geer, A.; Ker, K.; Muganyizi, P.; Prowse, D.; Roberts, I.

2026-07-18 obstetrics and gynecology 10.64898/2026.07.16.26358295 medRxiv
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Introduction Accurate measurement of blood loss after caesarean birth is important for early identification of postpartum haemorrhage. Commonly used visual estimation underestimates blood loss. We compared two methods for objectively assessing blood loss. Methods Measured blood loss was obtained by weighing swabs and pads combined with blood from suction and drapes. Calculated blood loss was derived from maternal weight and peripartum haemoglobin change. Data were from the I'M WOMAN trial investigating tranexamic acid for postpartum haemorrhage prevention. This was a secondary analysis of prospectively collected trial data. We reported median (IQR) blood loss, assessed agreement using Bland-Altman analysis and compared the percentages of women exceeding 500 ml, 1000 ml and 1500 ml. We graphed proportional haemoglobin drop by categories of measured blood loss, stratified by anaemia status. We compared AUCs for measured and calculated blood loss predicting haemodynamic compromise (shock index above 1.0) and death or near-miss. Results A total of 10,393 women were included in this study. Median measured and calculated blood loss were 545 ml (IQR 430-700) and 505 ml (IQR 180-908) respectively, with weak correlation (Spearmans rho=0.28). The IQR was wider for calculated blood loss than for measured blood loss, indicating greater variability. Bland-Altman analysis showed a small mean bias of -39 ml but wide limits of agreement (lower -1196 ml, upper 1118 ml). Measured versus calculated blood loss exceeded 500 ml in 60% versus 51% of women, 1000 ml in 7% versus 21%, and 1500 ml in 2% versus 8%. Women without anaemia had a greater proportional haemoglobin drop than women with anaemia for blood losses below 1000 ml. Measured blood loss had better predictive ability for death or near-miss (AUC 0.87 vs 0.76, p<0.001) and haemodynamic compromise (AUC 0.66 vs 0.62, p=0.001). Conclusion While median measured and calculated blood losses were similar, they were only weakly correlated. Calculated blood loss classified more women as having blood loss above higher thresholds. Women without anaemia had a greater proportional haemoglobin drop than women with anaemia for blood loss below 1000 ml. Measured blood loss had a modest advantage in predicting death or near-miss and haemodynamic compromise, but calculated blood loss remains an objective measure suitable as a trial outcome when direct measurement is not feasible.

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Modified Ghost System combining action, observation, and vibration stimulation for recovery after distal radius fracture surgery: A single-arm clinical feasibility study protocol

Kano, A.; Akiyama, Y.; Kamijo, Y.-I.; Hamaguchi, T.

2026-07-18 rehabilitation medicine and physical therapy 10.64898/2026.07.16.26358289 medRxiv
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Distal radius fractures (DRFs) can delay return to activities of daily living and social participation because of postoperative pain, temporary joint immobilization, and limited wrist and forearm range of motion. The Ghost System developed at Saitama Prefectural University, Japan, combines visual action observation with tendon vibration stimulation and has shown potential as an adjunct to conventional rehabilitation. This Study Protocol describes a modified Ghost system intended to improve clinical implementation by replacing the head-mounted virtual reality display with iPad-based action observation and by using a wristband-type vibrator. This single-center, single-arm, open-label feasibility trial will enroll 10 adults after palmar locking plate fixation for DRF. The intervention will be delivered twice weekly during outpatient rehabilitation follow-up sessions from the early postoperative period (postoperative days 2-10 after enrollment) through the approved early postoperative rehabilitation period (generally up to postoperative week 8), in parallel with standard rehabilitation practices. Primary feasibility and preliminary clinical outcomes include device fit and acceptability, pain assessed using a 100-mm Visual Analog Scale, and wrist/forearm range of motion. Secondary implementation and safety outcomes include Disabilities of the Arm, Shoulder and Hand (DASH), Patient-Rated Wrist Evaluation (PRWE), Hand20 Questionnaire (HANDS-20), EuroQol 5 Dimensions 5 Levels (EQ-5D-5L), body ownership and hand-illusion questionnaires, setup time, setup errors, adherence, adverse events, and device incidents. We hypothesize that the modified Ghost system will be feasible and acceptable for early postoperative outpatient rehabilitation and will be delivered without serious device-related adverse events. Clinical outcomes will be summarized descriptively to inform a future controlled study rather than to establish efficacy.

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Complement drives PNH red cell hemolysis independently of inflammasome activation

Ranjan, N.; Cole, M. A.; Gerber, G.; Flores-Guerrero, D.; Chaturvedi, S.; Brodsky, R.

2026-07-21 hematology 10.64898/2026.07.20.26358486 medRxiv
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Paroxysmal Nocturnal Hemoglobinuria (PNH) is characterized by hemolysis due to the loss of GPI-anchored complement regulators. While terminal complement inhibitors improve survival, the precise intracellular mechanisms driving the destruction of PNH erythrocytes remain controversial. A recently proposed model suggests PNH cells undergo an inflammatory programmed cell death ("spectosis") driven by an NLRP3-Caspase-8 signaling cascade. Here, we use a whole packed cell lysis approach to map the cytoskeletal degradation of primary erythrocytes across a 22-patient PNH cohort. Our data show that membrane attack complex (MAC) pore formation drives targeted {beta}-spectrin fragmentation, which correlates with rapid intracellular potassium (K+) efflux. Notably, when probing these primary patient samples, we detected a complete absence of the NLRP3 protein and found no functional evidence of Caspase-8 activation during MAC pore formation. Furthermore, caspase inhibition did not alter cytoskeletal degradation or K+ efflux. Instead, our data demonstrate that MAC-induced membrane perforation permits a rapid influx of calcium, which activates calpain, the dominant calcium-dependent protease in erythrocytes. Rather than an inflammatory cascade, this calcium-dependent calpain activity executes the degradation of {beta}-spectrin. These findings challenge current models of PNH hemolysis. We show that the destruction of PNH erythrocytes is a consequence of the MAC-calcium-calpain axis, rather than an inflammatory programmed cell death event. Consequently, therapeutic strategies aimed at targeting the inflammasome or caspase signaling will likely offer no clinical benefit for PNH patients.

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Modeling effect of hypertension control on death, incidence of atrial fibrillation and economic impact to Medicare and hospitals.

Williams, J.; Mencer, N.; Mak, W. Y.; Dalle Luche, G.; Dundovic, S.

2026-07-17 health systems and quality improvement 10.64898/2026.07.15.26358198 medRxiv
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Background Hypertension is a major modifiable risk factor for atrial fibrillation (AF), yet blood pressure (BP) control remains suboptimal in older U.S. adults. Objectives This study evaluated how improve systolic BP (SBP) control could affect incident AF, downstream AF ablation demand, Medicare savings, and hospital revenue. Methods A population-based modelling framework was developed to estimate mortality and incident AF hazards across SBP strata: <120, 120-139, 140-159, and ?160 mm/Hg. AF incidence in the SBP <120 mmHg group was set at 2.2 per 1,000 person-year, with hazard ratios of 1.17, 1.42 and 1.64 applied to higher SBP strata. We assumed 25% of incident AF patients would undergo ablation, with a 7.2% complication rate. AF prevalence was projected to increase by 4.6% annually over 10 years. Medicare savings and hospital revenue foregone were estimated under varying procedure cost and contribution-margin assumptions. Results Higher SBP was associated with greater hazards of death and incident AF. Improved SBP control reduced projected AF incidence and ablation demand. Over 10 years, cumulative Medicare savings were projected at $8.7B-$10.9B across the full modelled population. However, reduced ablation volume translated into hospital revenue foregone, ranging from $75M to $377M in the first year, and approximately $1.03B-$5.2B cumulatively over 10 years. Conclusions Improved SBP control may reduce AF incidence, prevent avoidable invasive ablation procedures, relieve pressure on surgical waitlists, and generate substantial Medicare savings. However, these benefits may reduce hospital procedural revenue, highlighting a misalignment between prevention-oriented care and fee-for-service reimbursement incentives.

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Clinician-Led Remote Hypertension Monitoring and Blood Pressure Control in a Majority-Minority Primary Care Cohort: Racial Disparities and Equity Implications

Mackey, R. J.; Bharucha, R.; Monte, A.; Spitznogle, A.; Baindur, A.; Sardar, D.; Zonna, X.; Gurusinghe, S.; Beeler, E.; Khan, A.; Xu, Y.; Walker, R. J.; Rich, E.

2026-07-15 primary care research 10.64898/2026.07.12.26357888 medRxiv
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Background Racial and ethnic minority populations face disproportionate rates of uncontrolled blood pressure (BP) and hypertension-related mortality. Remote hypertension monitoring (RHM) with active clinician-led medication titration has shown promise for improving BP control, but real-world evidence in majority-minority primary care settings remains limited. Methods This retrospective cohort study (January 2022-December 2024) enrolled adults with hypertension in a Bluetooth-integrated RHM program at a single urban academic primary care clinic. Of 550 patients enrolled, 503 with evaluable follow-up data were included. Patients transmitted daily home BP readings; clinicians reviewed readings monthly and titrated anti-hypertensive regimens per 2017 ACC/AHA guidelines. BP control was assessed at baseline and 3, 6, and 9 months. Factors associated with longitudinal BP control were examined using multivariable generalized estimating equations (GEE), with outcomes defined as strict control (<130/80 mmHg), at-least-moderate control (<140/90 mmHg), and uncontrolled (>140/90 mmHg). Results Among 503 participants (mean age 58.3 [SD 12.1] years; 63.6% African American; 52.9% male), BP control increased from 10.1% at baseline to 37.1% at 9 months. Each additional month of enrollment was associated with reduced odds of uncontrolled BP (adjusted odds ratio [aOR] 0.82; 95% CI, 0.80-0.85; P<.001). White race was associated with lower odds of uncontrolled BP versus African American race (aOR 0.57, at-least-moderate control; aOR 0.40, strict control; both P<.001). Male sex (aOR 1.46; P=.02) and congestive heart failure (aOR 2.09, strict control; aOR 2.05, at-least-moderate control; both P<.05) were associated with higher odds of uncontrolled BP. Conclusion Bluetooth-integrated RHM with active clinician-led medication titration was associated with a nearly 4-fold increase in BP control over 9 months in a majority-minority primary care population. Persistent within-program racial disparities underscore the need for equity-centered strategies beyond technology adoption alone. Prospective studies with concurrent usual-care comparators are needed to establish causal inference.

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Temperature modulation of microvascular, inflammatory and perceptual responses to mechanical loading of the skin in young and older adults and in spinal cord injury patients

Stevens, C. E.; Gordon, R. J. F. H.; Bergstrand, S.; Feldt, A.; Ghafouri, B.; Marginean, D.; Worsley, P. R.; Filingeri, D.

2026-07-15 dermatology 10.64898/2026.07.14.26358023 medRxiv
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Cooling the skin may increase its tolerance to mechanical loading and decrease the risk of developing pressure ulcers. Yet, the mechanisms of action (e.g. cooling-modulation of cytotoxic, post-occlusive hyperaemia), and their individual variability, remain unclear. We investigated the effects of different cooling levels (24{degrees}C and 16{degrees}C) on microvascular, inflammatory and perceptual responses to mechanical loading of the sacrum in healthy young (N=23) and older adults (N=19), and in spinal cord injury patients (SCI; N=10). Healthy participants underwent 45-min loading (~60 mmHg) and 20-min unloading of the sacrum, using an instrumented indenter probe set at either 38{degrees}C (control condition), 24{degrees}C or 16{degrees}C. SCI participants completed a more conservative protocol (i.e. 25min, ~45mmHg loading, 38{degrees}C and 16{degrees}C conditions). Pre-insult skin structure was characterised with optical coherence tomography; skin blood flow (SkBF) at the loading site was continuously measured, alongside thermal acceptability; and post-insult inflammatory responses were determined via skin-sebum cytokines analyses. Compared to control, 24{degrees}C- and 16{degrees}C-cooling induced a similar ~8-fold decrease in peak post-occlusive reactive hyperaemia in healthy participants, with similar temperature-related differences observed in SCI. Pro-inflammatory cytokines decreased post-insult; yet this occurred similarly across all temperatures and groups. The majority of participants ([&ge;]70%) rated both 24{degrees}C- and 16{degrees}C-cooling as thermally acceptable. We conclude that cooling is a potent modulator of the skin microvascular response to mechanical loading in younger, older, and vulnerable skin (SCI). These findings can inform design parameters for thermal technology aimed at preventing the loss of skin integrity (e.g. integrating 24{degrees}C-cooling in support surfaces and skin wearables).

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Association between Glycemic Traits and Delayed Cerebral Infarction among Non-Diabetic Patients with Aneurysmal Subarachnoid Hemorrhage: A Nested Case-Control Study

Ji, P.; Zheng, K.; Tan, D.; Xu, J.; Chen, M.; Wu, Y.; He, Z.

2026-07-20 neurology 10.64898/2026.07.18.26358375 medRxiv
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ABSTRACT Objective Delayed cerebral infarction (DCIn) is a severe complication following aneurysmal subarachnoid hemorrhage (aSAH). Previous studies suggest that glycemic variability is associated with DCIn. However, whether diabetes status modifies the relationship between glycemic traits and DCIn remains unknown. Methods Clinical data were collected from aSAH patients admitted to the First Affiliated Hospital of Shantou University Medical College between January 2015 and April 2025. The collected data included demographic characteristics, clinical variables, and glycemic traits. Glycemic traits included mean blood glucose (GLU-M), standard deviation of blood glucose (GLU-SD), coefficient of variation of blood glucose (GLU-CV), variance of blood glucose (GLU-Var), range of blood glucose (GLU-R), average real variability of blood glucose (GLU-ARV), and variability independent of the mean (GLU-VIM). After 1:2 case-control matching, conditional logistic regression models were used to evaluate the associations between glycemic traits and DCIn risk, with stratified analyses performed according to diabetes status. Multiplicative interaction terms were additionally included to assess the potential modifying effect of diabetes status. Results A total of 306 patients with aSAH were included. Among them, 102 developed DCIn cases. For each of these 102 cases, two controls were matched by age ({+/-}5 years), sex and year of admission ({+/-}5 years). In the overall population, higher GLU-M and GLU-ARV were associated with increased DCIn risk, with odds ratios (ORs) per 1-SD increase of 1.62 (95% CI, 1.25-2.11) and 1.63 (95% CI, 1.25-2.11), respectively. Among patients without diabetes (n=266), the associations with DCIn per 1-SD were observed for GLU-M (OR, 2.23; 95% CI, 1.56-3.19), GLU-SD (OR, 1.53; 95% CI, 1.13-2.06), GLU-Var (OR, 1.48; 95% CI, 1.04-2.10), and GLU-ARV (OR, 1.88; 95% CI, 1.38-2.55). No significant associations were observed among patients with diabetes. Significant interactions were observed between diabetes status and GLU-SD and GLU-Var, with P for interaction values of 0.033 and 0.032, respectively. Conclusion Higher mean blood glucose and greater glycemic variability are associated with an increased risk of DCIn in aSAH patients, especially in those without diabetes.