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Preprints posted in the last 7 days, ranked by how well they match Animals's content profile, based on 23 papers previously published here. The average preprint has a 0.03% match score for this journal, so anything above that is already an above-average fit.

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Chronicle of a Death Foretold: The Ecological Collapse of Sakumo Lagoon, Ghana

Akwetey, M. F. A.; Lamptey, E.; Abrokwah, S.; Aheto, D. W.; Mensah, P. K.; Okyere, I.; Akintola, S. L.; Pauly, D.

2026-07-15 ecology 10.64898/2026.07.14.738434 medRxiv
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Sakumo Lagoon, a small (1 km2) semi-open coastal lagoon in Ghana, lies between the cities of Accra and Tema. The lagoon and its surrounding wetland were designated a Ramsar Site in 1992, mainly because it served as a refuge for 66 local and migratory bird species. Its ecology, and the biology of its major fish species, notably the blackchin tilapia (Sarotherodon melanotheron) were thoroughly studied in 1971, when the lagoon was a diverse, mainly brackish ecosystem supporting a traditionally and well-managed fishery. In 2016-2017, another study found the lagoon mostly covered by floating vegetation and plastic waste. Finally, in 2024, a visual survey established that the floating vegetation had been almost completely replaced by terrestrial plants, with only a few square meters of garbage-strewn water in front of a culvert connecting the lagoon to the open sea. Several lagoons along the coast of Ghana have been similarly lost to urban sprawl and its various forms of pollution, but Sakumo Lagoon is a Ramsar Site, and its imminent disappearance should not remain undocumented.

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Ultrasound Detection of Early Callus Formation in Proximal Humerus Fractures: Protocol for a Pilot and Prospective Cohort Study

Blackman, B.; Fahey, N.; Dolan, S.; O'Reilly, M. K.; Cassidy, J. T.

2026-07-21 orthopedics 10.64898/2026.07.20.26358520 medRxiv
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Abstract Introduction: Proximal humerus fractures account for approximately 5-6% of all adult fractures and are primarily managed nonoperatively. Healing is conventionally monitored with radiographs, with radiopaque callus formation indicating healing. Visible radiographic callus appears weeks after biological union begins. Ultrasound provides a dynamic, radiation-free, and cost-effective method that can detect early callus formation before x-ray visibility. Although ultrasound has demonstrated utility for fracture healing in the clavicle and humeral shaft, its role in proximal humerus fractures remains unclear. Methods: This single-centre prospective study will be conducted in two phases. The pilot phase will measure inter-rater reliability for ultrasound detection of early callus formation at 2 and 4 weeks post-injury. Ten patients with proximal humerus fractures treated nonoperatively will undergo standardized anterior and lateral scans. Each patient will generate four saved images (short- and long-axis views), producing forty anonymized images independently reviewed by two raters. The prospective cohort phase will recruit approximately thirty additional patients. Results: Reliability will be quantified using Cohens kappa. A power calculation will be performed after pilot analysis. Results from the prospective cohort phase will help determine the association and predictive value of early ultrasound-detected bridging callus for radiographic and clinical union at three and six months. Patient reported outcome measures will be assessed using the Quick Disabilities of Arm, Shoulder and Hand (QuickDASH) questionnaire. Discussion: This study will develop and validate a standardized ultrasound protocol for assessing early fracture healing in proximal humerus fractures. By establishing both inter-rater reliability and predictive value, the findings may support ultrasound as a reproducible, radiation-free adjunct to conventional imaging and enable earlier identification of union status.

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CUSUM Analysis of the Initial Learning Curve for Robot-Assisted Gynecologic Surgery at a German Tertiary Center

Tahmasbi Rad, M.; Colacurci, D.; Bascharyar, E.; Bifulco, G.; Becker, S.; Shehaj, I.

2026-07-15 surgery 10.64898/2026.07.13.26357950 medRxiv
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Abstract Objective: To evaluate the initial learning curve of robot-assisted laparoscopic hysterectomy performed by a single surgeon during the implementation of robotic gynecologic surgery at a German tertiary university center using cumulative sum (CUSUM) analysis. Methods: This retrospective observational study included the first 66 consecutive patients who underwent robot-assisted laparoscopic hysterectomy using the da Vinci X surgical system between January 2022 and September 2023 at the University Hospital Frankfurt. Operative performance was assessed using CUSUM analysis of skin-to-closure time, console time, and docking time. Based on the CUSUM curve for operative time, cases were divided into two phases: phase 1 (cases 1 to 36) and phase 2 (cases 37 to 66). Demographic, perioperative, and postoperative outcomes were compared between phases. Results: Sixty-six patients were included. Median age was 48.5 years, and median BMI was 27.45 kg/m2. Previous abdominal surgery was present in 80.3% of patients, and 47% had endometriosis. At least 25% of cases had elevated BMI and large uterine volume. CUSUM analysis identified a transition point after 36 cases, indicating completion of the initial learning phase. Median skin-to-closure time significantly decreased from 108 minutes in phase 1 to 85.5 minutes in phase 2 (p=0.029). Console time and docking time showed progressive improvement, although these differences did not reach statistical significance. Perioperative outcomes, complication rates, conversion rates, postoperative pain scores, and hospital stay were comparable between phases. Conclusion: Robot-assisted laparoscopic hysterectomy demonstrates a well-defined learning curve, with procedural stabilization achieved after approximately 36 consecutive cases. The successful and safe implementation of robotic gynecologic surgery, even for complex cases, is feasible during the initial adoption phase at a tertiary university center when supported by structured training and standardized workflows.

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Validation of an Assessment Scale for a Low-Tech Laparoscopic Appendectomy Simulation and Its Relevance for Formative Self-Assessment

Tumameu Kouam, T. H.; Renoult, L.; Poitevin, M.; Jourdin, L.; Herve, C.; Meignan, P.; Podevin, G.; Schmitt, F.

2026-07-21 medical education 10.64898/2026.07.20.26358477 medRxiv
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Introduction: Laparoscopic appendectomy is an ideal procedure for acquiring laparoscopic skills through simulation. Nevertheless, technical training is time consuming for surgical trainers to provide constructive feedback, but this could be improved by the development of validated tools that enable appropriate formative self-assessment. For this reason, we developed a structured assessment scale for a laparoscopic appendectomy exercise using a low-fidelity simulator. The objective of this study was to validate the scale for use in formative self-assessment. Methods: During laparoscopic simulation sessions in 2025-2026, participants with varying levels of experience performed a standardized laparoscopic appendectomy (LAP) exercise on a low-fidelity simulator. Performance was assessed through formative self- and external assessment using a specific scale derived from the OSATS (Objective Structured Assessment of Technical Skills) score. Content and construct validity, internal consistency, reproducibility, and reliability in both hetero- and self-assessment were analyzed. Results: Thirty-two participants were included in the validation study of the LAP scale, including 7 medical students, 17 residents in pediatric, visceral, urological, and gynecological surgery, and 8 practicing surgeons. The content of the scale was deemed relevant by 80% of the users. It demonstrated excellent construct validity, with scores increasing according to level of experience: 9.9 +/- 0.7 among students, 12.7 +/- 3.3 among junior residents, 16.6 +/- 3.3 among experienced residents, and 18.8 +/- 0.9 among practicing surgeons (p < 0.0001). Reproducibility and internal consistency were significant, while inter and intrarater reliability were excellent (correlation coefficients r = 0.90 and 0.91; p < 0.0001), as was the correlation between external and self-assessment (r = 0.81; p < 0.0001). Self-assessment was more reliable among experienced learners than among novices. Conclusion: This standardized LAP scale is validated for both external and self-assessment, the latter requiring prior training to be reliable and formative.

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The mental health of farm wives

May, S.; Crossley, R. M.

2026-07-21 occupational and environmental health 10.64898/2026.07.20.26358460 medRxiv
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Objectives: Research on mental health in agriculture has increased in recent years; however, it remains largely focused on farmers themselves and is predominantly male-oriented. The mental health of farm wives and partners, many of whom play integral roles in farm operations, business management, and family life, remains difficult to characterise. This study therefore aims to explore the prevalence and causes of mental health challenges among farm wives and partners, and to investigate their use of, and barriers to, mental health support services. Methods: Quantitative data was collected using over 450 structured questionnaire responses that assessed mental health prevalence, contributing stressors and support service utilisation. Results: Findings indicate that there is a high prevalence of mental ill health amongst farm wives, seemingly due to industry stressors and support role overwhelm. Interpersonal relationships played a significant role in the types of mental distress experienced and highlighted the toll that farm life can take on farm wives' social and emotional connections. Despite a range of formal and informal support services being available, and effective when used, significant barriers to accessing these services were identified, including both practical difficulties and self-stigmatisation due to cultural beliefs. Conclusions: Farm wives and partners experience substantial mental health burdens linked to their diverse and often underrecognized roles within agricultural systems. In future, targeted interventions are needed to reduce stigma, improve service accessibility, and recognize women's contributions within farm enterprises. Further research and dedicated investment are also essential to better understand and help improve the mental health of this overlooked population within agricultural industries.

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Integrating estimation of eye health indicators into trachoma prevalence surveys: a feasibility study in Ethiopia and Nigeria

Han, X.; Roberts, C. h.; Adekeye, O. B.; Kedir, J.; Kura, Z.; Adekunle, D.; Carneiro, V. L. A.; Bishaw, T.; Boyd, S.; Dejene, M.; Gemechu, A.; Jimenez, C.; Kebede, F.; Katibeh, M.; Mpyet, C.; Olobio, N.; Ostendorf, C.; Solomon, A. W.; Taye, E.; Varga, B.; Witte, M.; Keel, S.; Harding-Esch, E. M.

2026-07-21 ophthalmology 10.64898/2026.07.20.26358377 medRxiv
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Background To evaluate the feasibility of generating data for eye health indicators (EHI), including effective refractive error coverage (eREC) and prevalence of vision impairment, in conjunction with trachoma prevalence surveys. Methods All individuals aged 6 years or more participating in trachoma prevalence surveys in two evaluation units (EUs) in each of Nigeria and Ethiopia were invited to participate. In parallel with the routine trachoma survey, a separate team assessed EHI metrics under two visual acuity (VA) measurement protocols. In Nigeria, one EU received the standard VA protocol, while the other received a simplified VA protocol. In Ethiopia, participants were randomised for protocol allocation. Acceptability and feasibility were assessed based on fieldwork cost and time and in-depth interviews with key stakeholders. Findings There were 3806 participants in Nigeria and 4259 in Ethiopia. Prevalence of distance and near vision impairment was 8.4% and 55.3% in Nigeria, and 6.2% and 54.2% in Ethiopia. Distance eREC was 0.0% (95%CI 0.0-0.0) in Nigeria and 1.2% (0.0-3.5) in Ethiopia under the standard protocol, and 0.9% (0.0-2.7) and 9.1% (0.6-17.7) under the simplified protocol. Near eREC was 0.4% (0.0-1.2) (standard) and 1.2% (0.0-2.5) (simplified) in Nigeria, and 2.1% (0.0-4.6) (standard) and 0.9% (0.0-2.1) (simplified) in Ethiopia. The integrated approach was more time- and cost-efficient compared to conducting separate trachoma and EHI surveys. Interviews indicated broad support among stakeholders for the integrated approach. Interpretation There was a large unmet refractive correction need in the participating communities. Integrating EHI measurement into trachoma surveys was acceptable and feasible.

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A Study Of Factors Influencing Fetal Monitor Failure

Tsanligrenchin, D.; Enkhjargal, E.-U.; Boldbaatar, O.; Shagdar, I.; Tumurtogoo, A.; Tuya, A.; Batbold, S.

2026-07-15 obstetrics and gynecology 10.64898/2026.07.12.26357884 medRxiv
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In Mongolia, an average of 65,000 women become pregnant each year, and about 59,500 babies are born. Although the number of pregnancies is decreasing by 8-12 percent each year, the level of fetal monitor usage remains high. The capital's maternity hospital currently has 27 fetal monitors in use, and an average of 30-35 calls are recorded per month. However, there is a lack of research on the use of fetal monitors, the causes and influencing factors of damage, and the organization of technical services. Therefore, this topic was chosen to determine the usage status of fetal monitors, the causes of malfunctions, and ways to improve them. Purpose To study the causes and factors affecting possible damage and injury during the use of fetal monitors, and to identify ways to reduce them. Materials and methods A one-time study was conducted on 10 MT-610 fetal monitors that were put into operation in 2019 at the Urgo Maternity Hospital in the capital. Data were collected and processed using document analysis methods from the technical passports and call logs of these devices. The factors contributing to common failures were identified using focus group interviews with the engineers and technicians responsible for the equipment. Results This study found that fetal monitor failures are caused by improper use, lack of regular calibration, electrical fluctuations, ambient temperature and humidity, and insufficient medical staff skills, training, and knowledge of how to use the device, all of which contribute to failures and measurement errors. It is also observed that when a replacement part is needed for a monitor that frequently breaks, the monitor is more likely to break again if it is used as a replacement from a previously broken monitor. Therefore, training doctors and nurses who replace spare parts on their use has been observed to significantly reduce future breakdowns. Conclusion According to the study results, the breakdowns and failures of fetal monitoring devices are mainly related to internal system failures, unstable power supply, and wear and tear of accessories and mechanical parts. The highest percentage of device failures indicates the need for special attention to the reliability of the device's basic functions. Additionally, the high percentage of accessory and printer failures indicates the need for proper use and monitoring of the entire device. In addition to technical factors, human misuse, lack of maintenance, and environmental influences also play a significant role in damage. Therefore, it is concluded that to ensure the reliable operation of fetal monitors, it is necessary to perform regular maintenance, stabilize the power supply, improve the quality of accessories, and increase the knowledge and skills of medical staff. Keywords: Fetal Monitoring, Equipment Failure, Risk Factors

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Learned landmark associations support online visual control under degraded visibility

Roessling, G.; Fajen, B.

2026-07-15 animal behavior and cognition 10.64898/2026.07.13.738310 medRxiv
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Humans and other animals often act in environments that are at least partly familiar, where aspects of the spatial layout are known. Although such knowledge is known to support navigation and spatial cognition, its role in the online control of action remains unclear. We investigated whether drivers use knowledge of road layout to guide steering in high and low visibility and, if so, the form of such knowledge. In two simulated driving experiments (total N = 90), participants repeatedly drove winding roads containing segments with and without fog. Drivers who repeatedly experienced the same road exhibited more stable steering and lane positioning than drivers encountering novel roads, but only when visibility was reduced. These advantages were accompanied by superior performance on post-tests assessing knowledge of road geometry. We next examined the form of such knowledge by dissociating global knowledge of road layout from local associations between landmarks and road segments. Disrupting landmark-road segment associations produced the largest impairment in steering performance. The benefits of prior experience were largely preserved when road-segment order was scrambled but landmark associations remained intact. These findings show that spatial knowledge can support moment-to-moment steering control when visibility is reduced. Rather than relying on a globally coherent representation of the environment, drivers use local associations between landmarks and upcoming road geometry to anticipate future demands. More broadly, the results elucidate how familiarity with environmental structure contributes to the control of action when visual information is degraded, revealing a close interplay between spatial knowledge and visual control. Significance StatementPeople routinely act within surroundings they have encountered before, from commuting on the same streets to walking familiar hallways. Whether the spatial knowledge acquired from such experience actually shapes online visual control remains an open question. Using a simulated driving task, we show that familiarity with a road improves steering stability specifically when visibility is reduced, and that this benefit depends on learned associations between landmarks and upcoming road geometry rather than a global cognitive map. The results indicate that spatial knowledge plays a key role in moment-to-moment control, letting drivers anticipate road segments they cannot yet see. Unfamiliar roads and impaired spatial learning may compound the risks of poor visibility, suggesting a role for driver-assistance systems that leverage landmarks.

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Procedural Pain, Rather Than Donor-Perceived Needle Quality, Is Associated With Willingness to Donate Again: A Multicenter Cross-Sectional Study in Bangladesh

hoque, a.; Rahman, M.; Basak, S. K.; Mamun, A. A.

2026-07-15 health policy 10.64898/2026.07.13.26357726 medRxiv
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Background Retaining repeat blood donors is essential for maintaining a safe and sustainable blood supply. While pain during venepuncture has been linked to lower donor return, the influence of donor-perceived needle quality on future donation remains unclear, particularly in low- and middle-income countries. This study examined whether perceived needle quality was associated with willingness to donate again among blood donors in Bangladesh. Methods We conducted a cross-sectional analytical study among 100 consecutively recruited whole-blood donors from participating blood donation centres in Bangladesh. Participants completed a structured questionnaire assessing demographic characteristics, donation history, procedural pain using a 10-point Visual Analogue Scale (VAS), pre-donation fear, perceived needle quality, vasovagal symptoms, overall satisfaction, and willingness to donate again on a five-point ordinal scale. Univariable ordinal logistic regression was used for variable screening, followed by multivariable proportional-odds ordinal logistic regression with purposeful variable selection. Statistical significance was set at p < 0.05. Results The mean donor age was 35.8 +/- 11.8 years, and 88% of participants were male. High procedural pain (VAS >= 4) was reported by 73% of donors, whereas 48% expressed high willingness to donate again. After adjustment, procedural pain was the only independent predictor of future donation intention. Each one-point increase in pain score reduced the odds of greater willingness to donate again by 54% (adjusted OR 0.46, 95% CI 0.37-0.57; p < 0.001). Donor-perceived needle quality was not associated with willingness to donate again (adjusted OR 1.09, 95% CI 0.47-2.56; p = 0.840) and showed no association with procedural pain. Conclusions Procedural pain, rather than donor-perceived needle quality, was the principal determinant of willingness to donate again. Interventions that improve donor comfort and minimise venepuncture pain may strengthen donor retention. Larger prospective studies using actual donor return behaviour are warranted.

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Safety Transparency in Animal Cell-Cultured Ingredients for Pet Food: A Case Study Establishing the Standard for Public Disclosure

Tewari, R.; Soukup, R.; Hadjistylianou, L.; Manicone, M.; Serra, M.; Felbermair, M.; Falconer, S.

2026-07-15 cell biology 10.64898/2026.07.14.738473 medRxiv
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Animal cell-cultured ingredients are entering the EU and UK pet food markets under frameworks that do not require pre-market, ingredient-level safety assessments, creating an ethical need for transparent safety disclosure. We present the first public safety dossier for this sector, describing the proprietary mouse embryonic stem cell line PE25 and its derived, non-viable cellular and conditioned media ingredient produced in food and feed-grade media. PE25 characterization confirmed Mus musculus identity, sterility, absence of mycoplasma and replication-competent retroviruses, and stable growth. Doxorubicin-induced p53 stress testing, CD44/BMI1 profiling, and soft agar assays showed no cancer-like traits and a non-tumorigenic profile; the final ingredient contains no viable cells. Independent OECD TG 471 and 487 assays confirmed non-genotoxicity. Heavy metals, biogenic amines, solvents, and chemical residues were below regulatory limits. Given process variability, we recommend case-by-case safety evaluation and propose this dossier as a model for responsible commercialization.

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From strandline vegetation to embryo dunes: natural sand retention along a heavily urbanized coast

Taelman, C.; Provoost, S.; Batsleer, F.; Bonte, D.; Van Uytvanck, J.

2026-07-15 ecology 10.64898/2026.07.14.738448 medRxiv
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1. Sandy beaches along urbanized coasts are increasingly managed through beach nourishment and hard infrastructure, yet these interventions often constrain natural dune-building processes. Along the Belgian coast, where much of the beach-dune interface is bordered by dikes, promenades and intensive recreation, strandline vegetation may provide an overlooked mechanism for retaining sand and initiating embryo dune development. 2. We assessed the potential for four pioneer dune plant species (Cakile maritima, Calamagrostis arenaria, Elymus farctus and Salsola kali) to establish, develop vegetation cover and contribute to sand accumulation along the Belgian coast. Using field surveys from 2017-2023, LiDAR-derived beach elevation and annual sediment dynamics, we modelled species occurrence and abundance/cover in low-disturbance reference zones and projected these relationships across the wider coastline. 3. Occurrence models identified where abiotic conditions allow plants to establish and persist until the late growing season, whereas zero-inflated abundance/cover models estimated expected vegetation development across environmental gradients. Predicted occurrence was widespread for several species, suggesting that the abiotic gradients modelled here are not the primary constraints on potential establishment across large parts of the coast. In contrast, expected abundance/cover showed stronger species-specific responses, particularly to sand accretion, indicating that sediment dynamics mainly affect post-establishment vegetation development rather than occurrence alone. 4. Independent field measurements of embryo dunes showed positive relationships between vegetation cover and local sand accumulation for all four species. When scaled using spatial predictions of potential abundance/cover, pioneer vegetation could retain substantial volumes of sand, with Cakile maritima contributing the largest share, followed by Salsola kali, Elymus farctus and Calamagrostis arenaria. Estimated volumes depended on assumptions about whether vegetation occurs as dispersed units or aggregated patches. 5. Synthesis and applications. Our results show that, even along a heavily urbanized and nourished coastline, abiotic conditions can support strandline vegetation and embryo dune initiation where disturbance is reduced. Management actions such as limiting trampling, adapting beach cleaning and protecting strandline vegetation could enhance the retention of nourished sand and support nature-based coastal defense. Rather than replacing engineered interventions, strandline vegetation may increase the efficiency with which available sediment is retained within the beach-dune system.

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Comparing different neuroimaging modalities for quantification of the cholinergic system in Parkinson's disease

d'Angremont, E.; Marschall, T. M.; Renken, R. J.; Sommer, I. E.

2026-07-17 neurology 10.64898/2026.07.15.26357522 medRxiv
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Introduction Parkinson's disease (PD) is a multifactorial disorder, affecting multiple neurotransmitter systems, including the cholinergic system. Cholinergic denervation is heterogeneous across patients and difficult to predict based on clinical presentation. In this study, we assessed the sensitivity of structural MRI (sMRI) and functional MRI (fMRI) to cholinergic degeneration related to PD and to cognitive functioning in PD. We compared our results to results from previously reported [18F]Fluoroethoxybenzovesamicol ([18F]FEOBV) PET imaging, which is considered the gold standard for cholinergic imaging. Methods 34 PD patients and 10 healthy controls underwent structural T1-weighted MRI. A subset of 14 patients and 9 controls also underwent resting-state fMRI. We extracted the bilateral volumes of the nucleus basalis of Meynert (NBM) from the sMRI images. Functional connectivity (FC) from the NBM to the cortex (NBM-FC) was determined using fMRI data. Principal component analysis (PCA) was applied to reduce the dimensionality of the NBM-FC images. We assessed performances for NBM-FC in distinguishing patients from controls using stepwise logistic regression. Similarly, NBM volume was used using logistic regression. Furthermore, the relation between these measures and cognitive function in several domains was investigated with (stepwise) linear regression. Leave-one-out cross validation (LOOCV) and bootstrapping was performed to assess robustness of the results. Results NBM-FC was well able to discriminate patients from controls with an AUC of 0.84 (95% CI: 0.62-1). NBM volume showed lower performance, but was still better than chance: AUC: 0.75 (95% CI: 0.57-0.93). Significant correlations were found between 1) cognition in the attentional domain and NBM-FC (r=0.63; p=.015) and 2) global cognition and NBM volume (r=0.55, p=.001). These results were inferior to those previously reported using [18F]FEOBV tracer uptake (see Chapter 6). Bootstrapping revealed that NBM volume of only the left hemisphere was stably related to PD diagnosis and global cognition in PD patients. We found that a lower NBM-FC in specific brain areas, including the fusiform gyrus, supramarginal gyrus and dorsolateral prefrontal cortex, was related to PD diagnosis. Bootstrapping revealed no stable NBM-FC pattern related to attention. Conclusion Although MRI results were slightly inferior to [18F]FEOBV PET data, MRI may provide a cheaper and more widely available alternative for cholinergic imaging. We recommend testing the utility of MRI as predictor and monitor of cholinergic treatment effect in a longitudinal study.

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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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Photobiomodulation promotes wound healing and functional improvement following lumbar decompression surgery: a double-blinded, placebo-controlled study

Rivera, J.; Zhou, Y.; Sak, L.; Pudewa, F.; Lee, J.; Yamamoto, M. T.; Yoo, H.; Lum, M.; Zhang, M.; Patel, A.; Vandenberghe, L. E.; Fenn, S. K.; Wang, Y.; Bailey, B.; Holley, S. M.; Vivas, A. C.; Holly, L. T.; Lu, D. C.

2026-07-17 surgery 10.64898/2026.07.15.26357882 medRxiv
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Objective: Photobiomodulation therapy has emerged as a promising modality to facilitate scar healing and pain management in dermatology and plastic surgery. However, its role in postoperative care following spine surgeries remains understudied. This double-blinded, placebo-controlled study aimed to investigate the effects of photobiomodulation in patients with chronic lower back pain undergoing lumbar decompression, with postoperative wound healing as the primary outcome and pain reduction and functional recovery as secondary outcomes. Methods: Patients were randomized to receive either active photobiomodulation braces (N=13) or placebo braces (N=12). Follow-up assessments were performed at 2, 4, 6, 8, and 12 weeks postoperatively. Outcomes included wound healing (Stony Brook Scar Evaluation Scale), back and leg pain (Visual Analog Scale), quality of life (EuroQol 5D), and functional status (Oswestry Disability Index). Results: Compared to the placebo group, the photobiomodulation treatment group had a 4.12-fold cumulative improvement in final scar scores, with significant between-group differences at postoperative weeks 6, 8, and 12 (p = 0.0062, 0.010, 0.042). Among patients with severe preoperative disability, treatment resulted in a 1.89-fold faster improvement in back pain (p=0.025) and a 1.80-fold faster improvement in ODI scores (p=0.025); and superior treatment effect on wound healing were again observed at weeks 6, 8, and 12. Among patients with poor initial scars, treatment led to a significantly better scar outcome than placebo at week 6 and a 1.94-fold faster EQ5D improvement (p=0.052), with significant gains observed as early as two weeks after surgery. There were no adverse events associated with photobiomodulation treatment. Conclusions: Photobiomodulation significantly promoted postoperative wound healing following lumbar decompression surgery, with therapeutic benefits preserved even in patients with poor baseline scar scores and functional impairment. This indicates that the efficacy of photobiomodulation is not limited by the initial scar condition or disability, supporting its broad clinical applicability. Additionally, patients with severe preoperative disability experienced greater benefits from photobiomodulation than placebo, including faster reduction in back pain and more rapid improvement in functional capacity, highlighting its role in postoperative pain management and rehabilitation. These therapeutic effects are likely mediated by photobiomodulation-induced reduction of inflammation and enhancement of tissue repair. Together, this study suggests that photobiomodulation can be a promising adjunct therapy to facilitate postoperative recovery in patients undergoing spine surgery.

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PARIS (Pneumonia: Acute Respiratory Infection +/- Sepsis): a prospective single-centre observational cohort study of hospitalised patients with pneumonia

Nasser, S. T.; Piercy, C. R.; Falinska, A.; O'Sullivan, D. M.; Devonshire, A.; Martinez-Estrada, F.; Huggett, J.; Creagh-Brown, B. C.

2026-07-17 respiratory medicine 10.64898/2026.07.15.26357955 medRxiv
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Introduction Hospitalised community-acquired pneumonia (CAP) is heterogeneous in aetiology, severity, and outcome. Phenotyping and endotyping approaches offer potential to stratify patients biologically and guide targeted therapy, but require well-characterised cohorts with linked biosamples. We describe the PARIS (Pneumonia: Acute Respiratory Infection +/- Sepsis) study: a prospective observational cohort of hospitalised patients with pneumonia, designed to characterise functional outcomes and to provide a biobank for translational immunological research. Methods Adults admitted with CAP to a single NHS district general hospital were enrolled within 24 hours of admission between December 2020 and March 2022. Clinical, functional, and physiological data were collected at enrolment, hospital discharge, and 6-8 week follow-up. Serial blood samples were collected for flow cytometry, transcriptomics, pathogen DNA detection, and plasma biobanking. Results Forty-seven patients were enrolled (15 without and 32 with sepsis [SOFA >=2] at enrolment); 87% met sepsis criteria by 24 hours post enrolment. Most patients (30/47, 64%) were managed as COVID-19, microbiologically confirmed in 27. Mean age was 57 years (SD 16), 70% were male, and baseline comorbidity burden was low. Severity was moderate (median NEWS2 4 at enrolment, rising to 6 by 24 hours post enrolment; p<0.001). Mortality was 4/47 (8.5%), with 44/47 (94%) alive at hospital discharge. Median length of stay was 8 days (IQR 5.5-11). Translational samples were collected from the majority: fresh flow cytometry (44/47, 94%), transcriptomics from the sepsis subgroup (31/32, 97%), pathogen DNA sampling (35 samples received across study timepoints; see Table 5), and stored plasma (29/47, 62%). The primary outcome of functional decline (Barthel score decrease >=1.85) occurred in only 1/29 patients with paired assessments (3.4%). Persistent CRP elevation (>3 mg/L) at 6-8 week follow-up was present in 16/31 (52%) survivors with available data. Conclusions The PARIS cohort provides a well-characterised clinical platform and linked biobank to support translational studies of pneumonia and sepsis. The low rate of functional decline reflects the younger, lower-comorbidity, COVID-predominant population recruited. Primary protocol endpoints were not achieved owing to pandemic-related disruption. Data and samples underpin a programme of linked translational studies.

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Rest-Activity Rhythm Variability Across Clinical Episodes of Bipolar Disorder: Standalone Biomarker or Statistical Artifact?

Konicarova, C.-A.; Schneider, J.; Spaniel, F.; Kolenic, M.; Alda, M.; Bakstein, E.

2026-07-17 psychiatry and clinical psychology 10.64898/2026.07.15.26358139 medRxiv
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Background: Actigraphy-derived rest-activity rhythm (RAR) features are widely used to characterize clinical states in bipolar disorder (BD). Both mean levels and temporal variability of these features have been associated with mood episodes; however, variability measures are often statistically coupled with the mean, particularly in skewed distributions. This raises a question as to whether variability reflects a separate characteristic of the data or whether the observed association arises from statistical properties of the data. Objective: In this study, we aim to determine whether temporal variability of actigraphy-derived RAR features provides standalone information on mood episodes in BD beyond mean activity levels after accounting for mean-variance dependence. Methods: We analyzed actigraphy data from a subset of 72 participants with BD drawn from a larger longitudinal study, extracting 22 daily RAR features aggregated weekly as sample mean (MEAN) and within-week temporal variability computed as sample standard deviation (VAR). Variance-stabilizing transformations (Box-Cox or Yeo-Johnson) were applied to the entire study cohort to reduce mean-variance dependence. Associations with mood episodes and remission (mania: n=34; depression: n=58 annotated participants) were evaluated using generalized linear mixed-effects models with a logistic link function, including univariate (MEAN or VAR) and multivariate (MEAN+VAR) specifications, assessed by likelihood-based metrics and the area under the receiver operating characteristic curve (AUC). Results: Transformations reduced mean-absolute correlations from 0.43 to below 0.06. Temporal variability remained significantly associated with clinical state for 11/22 RAR features in mania and 16/22 features in depression, with all significant associations remaining after false discovery rate correction (p<0.05). Joint models showed modest incremental gains (AUC 3%-4% overall; up to 12% in mania, 7% in depression), with absolute performance remaining limited (AUC 0.50-0.66). In both mania and depression, nearly all significant variability-based regressors contributed incremental information beyond mean-based models. Only sleep duration and activity changes around wake time (+-1 hour), did not improve discrimination between mania and remission. Conclusions: Temporal variability in RAR features can be considered a standalone state marker of mood episodes not captured by mean activity. We found it to be more consistently associated with depression than mania. Its incremental discriminative contribution is modest, suggesting greater utility within multivariate or multimodal frameworks.

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Reconsidering the case against risk prediction in self-harm: routinely collected health data distinguishes groups at higher and lower risk of adverse outcomes following paracetamol overdose

Oxley, J.; Schölin, L.; Brennan, G.; Anand, A.; Brett, J.; Eddleston, M.; Humphries, C.

2026-07-17 psychiatry and clinical psychology 10.64898/2026.07.15.26358127 medRxiv
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Background. UK clinical guidance recommends that structured risk prediction tools and risk stratification should not be used in self-harm, to predict suicide or determine who is offered treatment. Underpinning this position is the premise that routinely collected health data contain no useful predictive signal, which has received little direct scrutiny. Objective. To test whether routinely collected electronic health record data can distinguish groups at higher and lower risk of severe outcomes following paracetamol overdose. Methods. We analysed 4,095 adults presenting to NHS Lothian emergency departments with paracetamol overdose (2017-2023). Elastic-net logistic regression was fitted to 37 routinely collected electronic health record features to predict a composite of death or mental health inpatient admission at 0-7, 8-30 and 31-365 days following attendance, evaluated on a held-out 20% test set with bootstrapping. Findings. Events occurred in 5.5% of patients at 0-7 days, 2.0% at 8-30 days and 7.9% at 31-365 days, dominated by mental health admission. Bootstrap AUROC 95% confidence intervals lay above 0.5 in every window (0.65-0.82, 0.63-0.90, 0.71-0.85): models ranked patients better than chance. Calibration slopes (1.04, 1.14, 1.07) were close to one. Ranking drew primarily on mental health-related features. Conclusions. Routinely collected health data carried predictive signal for severe outcomes after paracetamol overdose, although discrimination fell short of what is needed for individual-level clinical use. Clinical implications. These models are not proposed for clinical deployment; however, treating risk prediction as a settled question will redirect research efforts, potentially excluding this patient population from machine learning advances driving improvements in care in other medical specialties.

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Machine learning and data-driven models for predicting post-stroke dysphagia: a systematic review and meta-analysis

Mohammadi Yazdi, S.; Motevaselian, M.; Khatami, S.; Radfar, N.; jourahmad, z.; Perez, H. A.

2026-07-17 neurology 10.64898/2026.07.15.26358113 medRxiv
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Background: Post-stroke dysphagia (PSD) contributes to aspiration, pneumonia, malnutrition, prolonged hospitalization and mortality. We evaluated the discrimination, validity and readiness of machine learning and data-driven prediction models for PSD-related outcomes. Methods: Following a prospectively registered protocol (PROSPERO CRD420261419259), we searched PubMed/MEDLINE, Embase, Web of Science Core Collection, CINAHL and CENTRAL from inception through June 7, 2026. Eligible studies developed or validated multivariable prediction models for PSD-related outcomes in adults with stroke. We used PROBAST and PROBAST+AI to assess risk of bias and applicability and TRIPOD+AI to evaluate reporting. Area under the curve (AUC) estimates were pooled on the logit scale with random-effects models. Results: Twenty-four studies were included and ten contributed to meta-analysis. Four studies predicting early or incident PSD yielded a pooled AUC of 0.94 (95% CI 0.60-0.99; I2 = 95.6%). Pooled AUCs were 0.84 (95% CI 0.71-0.92) for aspiration or penetration-aspiration and 0.89 (95% CI 0.24-1.00) for severe dysphagia. The exploratory analysis of all ten risk-prediction models produced an AUC of 0.90 (95% CI 0.80-0.95), but heterogeneity was substantial (I2 = 90.3%) and the prediction interval was 0.51-0.99. Every study had high risk of bias because of analysis-domain concerns; calibration and external validation were uncommon. Conclusions: Reported discrimination was often high, but the evidence does not establish reliable performance in care. Independent validation, calibration, complete model reporting and clinical-impact studies are needed before these models guide post-stroke swallowing care. Keywords: Post-stroke dysphagia; Stroke; Deglutition disorders; Machine learning; Clinical prediction model; Area under the curve; Meta-analysis

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Portable Ultra-Low Field MRI Deep-Learning Algorithms for White Matter Lesion Segmentation Improve Accuracy and Reflect Clinical Disability in Multiple Sclerosis

Thommana, A. A.; Donnay, C. A.; Norato, G.; Gaitan, M. I.; Griffanti, L.; Nair, G.; Reich, D. S.; Okar, S. V.

2026-07-17 neurology 10.64898/2026.07.15.26357954 medRxiv
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White matter lesion (WML) identification, assessment, and characterization using magnetic resonance imaging (MRI) are fundamental for diagnosis and monitoring of multiple sclerosis (MS). Portable ultra-low field (pULF) MRI at 64 millitesla (mT) has been shown to visualize WML with at least one dimension greater than 4 mm. An automated WML segmentation tool catered to pULF-MRI can provide standardized and accurate quantitative measurements of WML volume. In this study, we sought to investigate and compare the accuracy of machine-learning (ML) and deep-learning (DL) pULF MRI segmentation tools. Same-day paired pULF (64mT) and high-field (HF, 3T) MRI scans from 84 adults with MS or suspected-MS (mean age {+/-} SD: 48 {+/-} 13, 62 females) included T2-FLAIR and T1w images. Reference WML segmentations were manually annotated on pULF T2-FLAIR for all scans, with WML confirmed with registered HF T2-FLAIR. HF reference WML segmentations were created. Four automated segmentation methods were applied to pULF scans: Method for Inter-Modal Segmentation Analysis (MIMoSA), an ML algorithm trained on HF WML masks; WMH-SynthSeg, a convolutional neural network model with flexible segmentation capabilities across field strengths and resolution; nnU-Net, a DL algorithm trained on pULF reference WML masks; and Pseudo-Label Assisted nnU-Net (PLAn), a DL algorithm pre-trained on HF reference WML masks and refined with 64mT reference WML masks. Two models were trained with nnU-Net, one using T2-FLAIR images only (nnU-Net-FL) and one using T1w and T2-FLAIR images (nnU-Net-FL/T1). The same was done with PLAn, creating PLAn-FL and PLAn-FL/T1. The six automated WML segmentation outputs were compared to the manual segmentations to determine Dice Similarity Coefficient (DSC) scores. Associations of WML volume estimates with clinical measures were investigated. DSC scores with pULF reference WML masks from PLAn-FL (DSC mean {+/-} SD: 0.50 {+/-} 0.24) outperformed MIMoSA (0.24 {+/-} 0.20, p < 0.0001), WMH-SynthSeg (0.30 {+/-} 0.18, p < 0.0001), nnU-Net-FL (0.41 {+/-} 0.24, p < 0.0001), and nnU-Net-FL/T1 (0.41 {+/-} 0.26, p = 0.0004). Worse Expanded Disability Status Scale (EDSS) and Scripps Neurologic Rating Scale (SNRS) scores were correlated with higher WML volumes in the pULF and HF reference masks. They were also correlated with WML volumes derived from WHM-SynthSeg, nnU-Net-FL, nnU-Net-FL/T1, PLAn-FL, and PLAn-FL/T1, but not MIMoSA. After adjusting for age, WHM-SynthSeg, nnU-Net FL, nnU-Net-FL/T1, PLAn-FL, and PLAn-FL/T1 had significant associations with EDSS and SNRS scores. nnU-Net and PLAn performed best in segmenting WML on pULF-MRI at 64 mT, providing accurate quantitative estimates of WML burden. Moreover, WML volumes estimated by these algorithms were associated with clinical measures of disability, underscoring their utility for reflecting clinical and radiological disease severity. Given pULF-MRI's mobility and lower cost, these findings highlight its relevance in clinical trials, particularly in involving more participants who face logistical constraints and barriers.

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Association between serum CEA levels and ctDNA-detected Epidermal Growth Factor Receptor mutations in lung adenocarcinoma

Roy, S.; Soroar, M. K. I.; Ara, H.; Nur, S. A.; Akanda, R. A.; Saha, S.; Alam, M. M.

2026-07-17 oncology 10.64898/2026.07.14.26358115 medRxiv
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Background with objective: Detecting EGFR mutations is critical for treating lung adenocarcinoma with highly effective targeted therapies. However, standard genetic testing is expensive, complex, and often unavailable in resource-limited settings like Bangladesh. Because elevated serum CEA has been linked to these genetic alterations, it could serve as an accessible screening tool. This study aims to evaluate the association between serum CEA levels and EGFR mutation status to determine if routine CEA testing can reliably predict these mutations and guide treatment. Methodology: In this cross-sectional analytical study, we recruited 58 patients with histologically confirmed treatment naive lung adenocarcinoma. The presence of EGFR mutations in the ctDNA was determined via ARMS (Amplification Refractory Mutation System) PCR. Patient data was statistically analyzed to assess the diagnostic correlation between serum CEA levels and the presence of EGFR mutations. Result: The overall EGFR mutation rate was 43.1% with exon 19 deletion (48%) and exon 21 mutations (44%) were the predominant types. Median serum CEA levels were significantly higher in patients with EGFR mutations compared to wild-type cases (14.6 ng/ml vs 2.8 ng/ml, p<0.001). A multivariate analysis revealed a 14% increased likelihood of an EGFR mutation for 1 ng/ml rise in serum CEA. Furthermore, serum CEA showed strong diagnostic accuracy for ctDNA samples at a 6.39 ng/ml cut-off (AUC 0.82, sensitivity 68.0%, specificity 84.8%). Conclusion: Serum CEA is a valuable, cost-effective, and non-invasive biomarker demonstrating significantly higher levels and strong diagnostic accuracy in EGFR-mutated lung adenocarcinoma compared to wild-type cases.