Háskólinn í Reykjavík

Permanent URI for this collectionhttps://hdl.handle.net/20.500.11815/5667

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Melatonin MT1 Receptor Expression in Luminal Invasive Ductal Breast Carcinoma in Postmenopausal Women
(2025-04) Pistiolis, Leda; Alawieh, Sahar; Halldórsdóttir, Þórhildur; Kovács, Anikó; Olofsson Bagge, Roger
Laboratory and animal studies indicate that melatonin exerts a negative impact on breast cancer progression and metastasis. These actions are both receptor-dependent and -independent. Of the two transmembrane melatonin receptors identified in humans, breast cancer expresses only MT1. The aim of this study was to investigate the expression of MT1 in hormone-receptor-positive, HER2-negative invasive ductal breast carcinoma in postmenopausal women and its possible correlations with clinicopathological parameters and survival. A total of 118 patients with luminal A/B primary breast cancer with or without axillary metastases were identified. The MT1 receptor expression was immunohistochemically assessed as a percentage of stained cells and a weighted index (WI) (percentage multiplied by staining intensity). Most tumor samples (84.7%) and metastasized lymph nodes (96%) stained positive for MT1, with varying intensity. No statistically significant correlations were found between the MT1 expression or the WI in the primary tumor and the patient and tumor characteristics, or the MT1 and WI in the metastasized lymph nodes. The survival analysis did not reveal a significant effect of MT1 expression or the WI on the risk of recurrence or survival.
Impact of different chemical debridement agents on early cellular responses to titanium dental implants : A transcriptome-based in vitro study on peri-implant tissue regeneration
(2025-09) Wang, Qiang; Haugen, Håvard Jostein; Linke, Dirk; Lyngstadaas, Ståle Petter; Sigurjónsson, Ólafur Eysteinn; Ma, Qianli; Department of Engineering
Background: Poor peri-implant health leads to biofilm accumulation, peri-implantitis, and bone loss. Chemical debridement may help maintain peri-implant health, but its effects on peri-implant cells remain unclear. Methods: Five cleaning agents—hydrogen peroxide (H2O2), Poloxamer, H2O2 +Poloxamer, Perisolv, and Paroex—were applied on titanium (Ti) surfaces. Mouse pre-osteoblasts (MC3T3-E1), human gingival fibroblasts (HGF), and human bone marrow stromal cells (hBMSC) were cultured on agent-treated Ti surfaces for up to 120 minutes to assess morphology, cytotoxicity, adhesion, and proliferation. RNA sequencing was performed on hBMSC. Results: Except for Poloxamer, all treatments inhibited cellular spreading. Paroex increased cytotoxicity and inhibited proliferation. Perisolv impaired hBMSC adhesion and variably affected proliferation. H2O2, alone or with Poloxamer, elevated cytotoxicity and inhibited adhesion in hBMSCs but not MC3T3-E1 or HGF. In contrast, Poloxamer-treated Ti surfaces enhanced adhesion and proliferation across all cell types. RNA sequencing revealed that oxidant-based treatments (H2O2, H2O2 +Poloxamer, Perisolv) suppressed key genes for proliferation (HMGA2, JAG1, NOTCH1, YAP1, TBX3), anti-apoptosis (MCL1, BCL2L2), and adhesion (ITGA2, ITGB3, SPP1), while inhibiting MAPK, PI3K-Akt, and pluripotency pathways. Conclusion: Commercial agents like Perisolv and Paroex impair hBMSC function, with Paroex demonstrating significant cytotoxicity. H2O2 exhibits toxicity, particularly to hBMSCs. Poloxamer improves cell attachment and growth. Given these findings, careful selection of debridement agents is critical to balance cleaning efficacy and cytocompatibility. The adverse effects on hBMSCs necessitate prompt removal postapplication. Further research on biomaterials supporting tissue regeneration postdebridement is needed to restore peri-implant health.
Phase slips extracted from derivatives of EEG data provide a deeper insight into the formation of cortical phase transitions
(2025-02-25) Ramon, Ceon; Gargiulo, Paolo; Department of Engineering
The phase slips are generally extracted from the EEG using Hilbert transforms but could also be extracted from the derivatives of EEG, providing additional information about the formation of cortical phase transitions. We examined this from the 30 s long, 256-channel resting state, eyes open EEG data of a 30-year-old male subject. The phase slip rates, PSR1 from EEG, PSR2 from the first-order derivative of EEG, and PSR3 from the second-order derivative of EEG, respectively, were extracted. The study was performed in the alpha (7-12 Hz) band only. The spatiotemporal plots of the EEG and phase slip rates over a 3.0 s period with a 0.5 s resolution were made with a montage layout of the 256 electrode positions. The spatiotemporal patterns of EEG and its derivatives exhibited shifting activity from posterior visual areas to the central and frontal regions over the 3.0 s period. The PSR1, PSR2, and PSR3 activity areas were different from the EEG and were distributed in larger areas as compared with the EEG and its derivatives. Also, the PSR2 and PSR3 activity areas and magnitudes were significantly different as compared with the PSR1 alone. This was also confirmed (p < 0.01) by the one-way ANOVA analysis of the means of PSR1, PSR2, and PSR3. These results show that PSR2 and PSR3 carry additional information that could potentially be biomarkers for studying the rate of formation of phase slips and the related cortical activity from the derivatives of EEG data.
Missense variants in FRS3 affect body mass index in populations of diverse ancestries
(2025-03-25) DBDS Genomic Consortium; Jónsdóttir, Andrea Björg; Ægisdóttir, Hildur Margrét; Arnar, Davíð Ottó; Bjarnason, Ragnar Grímur; Halldórsson, Gísli Hreinn; Jónsdóttir, Ingileif; Melsted, Páll; Stefánsdóttir, Lilja; Steingrímsdóttir, Þóra; Teitsdóttir, Unnur Diljá; Þorsteinsdóttir, Unnur; Ulfarsson, Magnus O; Víkingsson, Arnór; Walters, Guðmundur Bragi; Helgason, Agnar Freyr; Halldórsson, Bjarni Vilhjálmur; Stefánsson, Kári
Obesity is associated with adverse effects on health and quality of life. Improved understanding of its underlying pathophysiology is essential for developing counteractive measures. To search for sequence variants with large effects on BMI, we perform a multi-ancestry meta-analysis of 13 genome-wide association studies on BMI, including data derived from 1,534,555 individuals of European ancestry, 339,657 of Asian ancestry, and 130,968 of African ancestry. We identify an intergenic 262,760 base pair deletion at the MC4R locus that associates with 4.11 kg/m2 higher BMI per allele, likely through downregulation of MC4R. Moreover, a rare FRS3 missense variant, p.Glu115Lys, only found in individuals from Finland, associates with 1.09 kg/m2 lower BMI per allele. We also detect three other low-frequency FRS3 missense variants that associate with BMI with smaller effects and are enriched in different ancestries. We characterize FRS3 as a BMI-associated gene, encoding an adaptor protein known to act downstream of BDNF and TrkB, which regulate appetite, food intake, and energy expenditure through unknown signaling pathways. The work presented here contributes to the biological foundation of obesity by providing a convincing downstream component of the BDNF-TrkB pathway, which could potentially be targeted for obesity treatment.
Assessing neuromuscular system via patellar tendon reflex analysis using EMG in healthy individuals
(2025-01-30) Khatun, Zakia; Kristinsdóttir, Sara; Thóra Thórisdóttir, Arndís; Björk Halldórsdóttir, Linda; Tortorella, Francesco; Gargiulo, Paolo; Helgason, Þórður; Department of Engineering
Patellar tendon reflex tests are essential for evaluating neuromuscular function and identifying abnormalities in nerve conduction and muscle response. This study explored how age, height, weight, and gender influence reflex response times in healthy individuals, providing a reference for future research on different neuromuscular conditions. We analyzed reflex onset, endpoint, and total duration of reflexes using electromyography (EMG) recordings from 40 healthy participants. Reflexes were elicited by striking the patellar tendon, and participants were grouped based on age, height, weight, and gender. We investigated both the individual and combined effects of these factors on reflex response times. Additionally, height and weight-normalized data were analyzed to clarify their roles in influencing reflexes across age groups. Gender-specific analyses were conducted as well to assess potential differences between males and females. Our findings indicated that reflex onset was significantly delayed in elderly individuals, particularly in taller and heavier individuals, and in males compared to females. Even with height normalization, elderly participants showed slower reflexes. Weight-normalized data revealed that younger participants exhibited longer total reflex durations, likely due to their greater height, which impacted nerve conduction time. This trend was consistent across genders, with males generally exhibiting longer duration of reflex response times. These findings provide insights into how different demographic factors, particularly aging, affect neuromuscular reflexes and could serve as a reference for diagnosing and monitoring neuromuscular disorders.
Ejtm3 experiences after ChatGPT and other AI approaches : values, risks, countermeasures
(2025-03-31) Fanò-Illic, Giorgio; Coraci, Daniele; Maccarone, Maria Chiara; Masiero, Stefano; Quadrelli, Marco; Morra, Aldo; Ravara, Barbara; Pond, Amber; Forni, Riccardo; Gargiulo, Paolo; Department of Engineering
We invariably hear that Artificial Intelligence (AI), a rapidly evolving technology, does not just creatively assemble known knowledge. We are told that AI learns, processes and creates, starting from fixed points to arrive at innovative solutions. In the case of scientific work, AI can generate data without ever having entered a laboratory, (i.e., blatantly plagiarizing the existing literature, a despicable old trick). How does an editor of a scientific journal recognize when she or he is faced with something like this? The solution is for editors and referees to rigorously evaluate the track records of submitting authors and what they are doing. For example, false color evaluations of 2D and 3D CT and MRI images have been used to validate functional electrical stimulation for degenerated denervated muscle and a home Full-Body In-Bed Gym program. These have been recently published in Ejtm and other journals. The editors and referees of Ejtm can exclude the possibility that the images were invented by ChatGPT. Why? Because they know the researchers: Marco Quadrelli, Aldo Morra, Daniele Coraci, Paolo Gargiulo and their collaborators as well! Artificial intelligence is not banned by the EJTM, but when submitting their manuscripts to previous and to a new Thematic Section dedicated to Generative AI in Translational Mobility Medicine authors must openly declare whether they have used artificial intelligence, of what type and for what purposes. This will not avoid risks of plagiarism or worse, but it will better establish possible liabilities.
Chitosan–saccharide conjugates for eradication of Pseudomonas aeruginosa biofilms
(2024-05-23) Sahariah, Priyanka; Papi, Francesco; Merz, Koi L.; Sigurjónsson, Ólafur Eysteinn; Meyer, Rikke Loiuse; Nativi, Cristina; Department of Engineering
The problem of antibiotic resistance has raised serious concerns globally and hence the development of new materials which can combat these drug-resistant strains has gained a great deal of attention. Herein, we report the use of a biocompatible material, chitosan, as a scaffold to graft saccharides which can specifically target Pseudomonas aeruginosa. We realized this by synthesizing N-functionalized chitosan conjugates by coupling chitosan to fucose and galactose moieties which intercept Pseudomonas aeruginosa lectins and target the bacterial biofilms. A series of six conjugates containing similar proportions of cationic and sugar moieties were synthesized by direct modification of the chitosan backbone using a method that is highly efficient and reproducible. The conjugates showed a bactericidal effect against both Gram positive and Gram negative bacterial strains. An investigation into the antibiofilm activity of the conjugates revealed the optimum combination of the type and positioning of the functionalities that were highly effective in eradicating Pseudomonas aeruginosa biofilms. 2D and 3D imaging of the conjugate-treated biofilms using confocal laser scanning microscopy (CLSM) allowed us to determine that the conjugates not only acted on the surface but also dispersed into deep layers of the biofilm. Interaction between the conjugates and individual bacterial cells in the biofilm was further confirmed by fluorescence labelling of the conjugates and imaging by CLSM.
Complete human recombination maps
(2025-01-22) Palsson, Gunnar; Hardarson, Marteinn T.; Jonsson, Hakon; Steinthorsdottir, Valgerdur; Stefansson, Olafur A.; Eggertsson, Hannes P.; Gudjonsson, Sigurjon A.; Olason, Pall I.; Gylfason, Arnaldur; Masson, Gisli; Thorsteinsdottir, Unnur; Sulem, Patrick; Helgason, Agnar; Gudbjartsson, Daniel F.; Halldorsson, Bjarni V.; Stefansson, Kari
Human recombination maps are a valuable resource for association and linkage studies and crucial for many inferences of population history and natural selection. Existing maps1, 2, 3, 4–5 are based solely on cross-over (CO) recombination, omitting non-cross-overs (NCOs)—the more common form of recombination6—owing to the difficulty in detecting them. Using whole-genome sequence data in families, we estimate the number of NCOs transmitted from parent to offspring and derive complete, sex-specific recombination maps including both NCOs and COs. Mothers have fewer but longer NCOs than fathers, and oocytes accumulate NCOs in a non-regulated fashion with maternal age. Recombination, primarily NCO, is responsible for 1.8% (95% confidence interval: 1.3–2.3) and 11.3% (95% confidence interval: 9.0–13.6) of paternal and maternal de novo mutations, respectively, and may drive the increase in de novo mutations with maternal age. NCOs are substantially more prominent than COs in centromeres, possibly to avoid large-scale genomic changes that may cause aneuploidy. Our results demonstrate that NCOs highlight to a much greater extent than COs the differences in the meiotic process between the sexes, in which maternal NCOs may reflect the safeguarding of oocytes from infancy until ovulation.
Data-driven deep learning models in particle-laden turbulent flow
(2025-02-01) Hassanian, R.; Helgadóttir, I.; Gharibi, F.; Beck, A.; Riedel, M.
The dynamics of inertial particles in turbulent flow are complex, and in practice, gravity influences particle dynamics. However, the effects of gravity have not been appropriately investigated using numerical approaches. This study provides the first empirical evidence of a data-driven deep learning (DL) model to predict the velocity, displacement, and acceleration of inertial particles in a strained particle-laden turbulent flow. This study introduces a DL model to experimental data from Hassanian et al., who investigated distorted turbulent flow within a specific range of Taylor microscale Reynolds number, 100 < R e λ < 120 . The flow experienced a vertical mean strain rate of 8 s−1 under the influence of gravity. Lagrangian particle tracking technique was employed to capture each inertial particle's velocity field and displacement. The deep learning model relies on experimental particle-laden turbulent flow, demonstrating all effective parameters, including turbulence intensity, strain rate, turbulent energy dissipation rate, gravity, particle size, particle density, and small and large-scale effects. The forecasting model demonstrates significant capability and high accuracy in generating predictions closely aligned with the actual data. Model training and inference are run on the high-performance computing DEEP-DAM system at the Jülich Supercomputing Center. The proposed approach can potentially enhance the understanding of inertial particle dynamics and the parameters that affect them. Furthermore, data-driven models can offer new insights into particle motion and the underlying differential equations within physics-based deep learning frameworks.
Soluble Proteins From Conventional and Organic Eggshell Membranes With Different Proteomic Profiles Show Similar In Vitro Biofunctions
(2025-01) Ma, Qianli; Piaia, Lya; Loca, Dagnija; Rubenis, Kristaps; Locs, Janis; Thiede, Bernd; Sigurjónsson, Ólafur Eysteinn; Haugen, Håvard Jostein; Department of Engineering
The eggshell membrane (ESM), resembling the extracellular matrix (ECM), acts as a protective barrier against bacterial invasion and offers various biofunctions due to its porous structure and protein-rich composition, such as ovalbumin, ovotransferrin, collagen, soluble protein, and antimicrobial proteins. However, the structure of ESM primarily comprises disulfide bonds and heterochains, which poses a challenge for protein solubilization/extraction. Therefore, the method of dissolving and extracting bioactive protein components from ESM has significant potential value and importance for exploring the reuse of egg waste and environmental protection. In this study, soluble ESM proteins (SEPs) were extracted from conventional (industrial-fed) and organic (free-grounded) using an acidic 3-mercaptopropionic acid (3-MPA) extraction strategy. FTIR was employed to monitor the chemical changes in the ESM, while LC–MS/MS was used to conduct the proteomic analysis. The biocompatibility and effects of SEP cocktails on ECM synthesis were also investigated. The results indicated that the acidic 3-MPA strategy effectively altered the ESM chemical composition, thereby facilitating SEPs extraction. The SEPs from conventional and organic eggs have different protein profiles but with partial overlapping. SEPs from both sources showed similar desirable biosafety profiles and dose-dependent promotion of osteoblastic (ECM) component synthesis, suggesting that different egg sources may contribute to consistent core biological functions of protein products, they may also introduce different functional priorities.
A partial loss-of-function variant in STAT6 protects against type 2 asthma
(2025-01) Kristjansdottir, Katla; Norddahl, Gudmundur L; Ivarsdottir, Erna V; Halldórsson, Gísli Hreinn; Einarsson, Gudmundur; Bjarnadottir, Kristbjorg; Rutsdottir, Gudrun; Arnthorsson, Asgeir O; Erikstrup, Christian; Gudmundsdottir, Steinunn; Gunnarsdottir, Kristbjorg; Gunnbjörnsdóttir, María I; Halldórsson, Bjarni Vilhjálmur; Holm, Hilma; Lúðvíksdóttir, Dóra; Lúðvíksson, Björn Rúnar; Brunak, Søren; Bruun, Mie Topholm; Mikkelsen, Christina; Mikkelsen, Susan; Jensen, Bitten Aagaard; Sørensen, Erik; Thomsen, Simon Francis; Ullum, Henrik; Ólafsson, Ísleifur; Önundarson, Páll Torfi; Ostrowski, Sisse Rye; Sævarsdóttir, Sædís; Sigurdardottir, Olof; Sigurgeirsson, Bardur; Snaebjarnarson, Audunn S; Sveinbjornsson, Gardar; Thorlacius, Gudny E; Thorleifsson, Gudmar; Tragante, Vinicius; Vidarsson, Brynjar; Porsbjerg, Celeste; Björnsdóttir, Unnur Steina; Sulem, Patrick; Gudbjartsson, Daniel F; Melsted, Páll; Pedersen, Ole Bv; Jónsdóttir, Ingileif; Olafsdottir, Thorunn A; Stefánsson, Kári
BACKGROUND: Signal transducer and activator of transcription 6 (STAT6) is central to type 2 (T2) inflammation, and common noncoding variants at the STAT6 locus associate with various T2 inflammatory traits, including diseases, and its pathway is widely targeted in asthma treatment. OBJECTIVE: We sought to test the association of a rare missense variant in STAT6, p.L406P, with T2 inflammatory traits, including the risk of asthma and allergic diseases, and to characterize its functional consequences in cell culture. METHODS: The association of p.L406P with plasma protein levels, white blood cell counts, and the risk of asthma and allergic phenotypes was tested. Significant associations in other cohorts were also tested using a burden test. The effects of p.L406P on STAT6 protein function were examined in cell lines and by comparing CD4+ T-cell responses from carriers and noncarriers of the variant. RESULTS: p.L406P associated with reduced plasma levels of STAT6 and IgE as well as with lower eosinophil and basophil counts in blood. It also protected against asthma, mostly driven by severe T2-high asthma. p.L406P led to lower IL-4-induced activation in luciferase reporter assays and lower levels of STAT6 in CD4+ T cells. We identified multiple genes with expression that was affected by the p.L406P genotype on IL-4 treatment of CD4+ T cells; the effect was consistent with a weaker IL-4 response in carriers than in noncarriers of p.L406P. CONCLUSIONS: A partial loss-of-function variant in STAT6 resulted in dampened IL-4 responses and protection from T2-high asthma, implicating STAT6 as an attractive therapeutic target.
Impulsive Buying and Deferment of Gratification among Adults with ADHD
(2024) Einarsson, Sverrir Björn; Sigurðsson, Baldur Heiðar; Kjartansdóttir, Sigurlín Hrund; Magnússon, Páll; Sigurdsson, Jón Fridrik; Department of Psychology
Background: Impulsivity symptoms have been studied thoroughly in adults with ADHD, including hasty actions and decisions without considering possible consequences. The objective of our study was to investigate impulsive buying and deferment of gratification among adults with ADHD and a comparison group. Method: The participants were 225 adults with ADHD and 121 university students who completed the Buying Impulsiveness Scale (BIS), the Deferment of Gratification Questionnaire (DOGQ), the Adult ADHD Rating Scale - IV (ADHD-RS), as well as background questions. Results: Significant differences were found between the two groups on the three scales, the ADHD group showing more ADHD symptoms, more frequent impulsive buying behaviour and less ability to defer gratification. Mediation analyses yielded significant indirect effects in both samples, which suggests that the relationship between ADHD symptoms and impulsive buying is mediated by the ability to defer gratification. Conclusion: The results suggest that placing emphasis on improving the capacity of adults with ADHD to defer gratification might be beneficial in treatment.
Mechanical and Biological Characterization of Ionic and Photo-Crosslinking Effects on Gelatin-Based Hydrogel for Cartilage Tissue Engineering Applications
(2024-10) Boretti, Gabriele; Baldursson, Hafsteinn Esjar; Buonarrivo, Luca; Simonsson, Stina; Brynjólfsson, Sigurður; Gargiulo, Paolo; Sigurjónsson, Ólafur Eysteinn; Department of Engineering
Articular cartilage degeneration poses a significant public health challenge; techniques such as 3D bioprinting are being explored for its regeneration in vitro. Gelatin-based hydrogels represent one of the most promising biopolymers used in cartilage tissue engineering, especially for its collagen composition and tunable mechanical properties. However, there are no standard protocols that define process parameters such as the crosslinking method to apply. To this aim, a reproducible study was conducted for exploring the influence of different crosslinking methods on 3D bioprinted gelatin structures. This study assessed mechanical properties and cell viability in relation to various crosslinking techniques, revealing promising results particularly for dual (photo + ionic) crosslinking methods, which achieved high cell viability and tunable stiffness. These findings offer new insights into the effects of crosslinking methods on 3D bioprinted gelatin for cartilage applications. For example, ionic and photo-crosslinking methods provide softer materials, with photo-crosslinking supporting cell stretching and diffusion, while ionic crosslinking preserves a spherical stem cell morphology. On the other hand, dual crosslinking provides a stiffer, optimized solution for creating stable cartilage-like constructs. The results of this study offer a new perspective on the standardization of gelatin for cartilage bioprinting, bridging the gap between research and clinical applications.
BreathFinder : A Method for Non-Invasive Isolation of Respiratory Cycles Utilizing the Thoracic Respiratory Inductance Plethysmography Signal
(2024-08-21) Holm, Benedikt; Borský, Michal; Arnardóttir, Erna Sif; Serwatko, Marta; Mallett, Jacky; Islind, Anna Sigríður; Óskarsdóttir, María; Department of Engineering; Department of Computer Science
INTRODUCTION: The field of automatic respiratory analysis focuses mainly on breath detection on signals such as audio recordings, or nasal flow measurement, which suffer from issues with background noise and other disturbances. Here we introduce a novel algorithm designed to isolate individual respiratory cycles on a thoracic respiratory inductance plethysmography signal using the non-invasive signal of the respiratory inductance plethysmography belts. PURPOSE: The algorithm locates breaths using signal processing and statistical methods on the thoracic respiratory inductance plethysmography belt and enables the analysis of sleep data on an individual breath level. PATIENTS AND METHODS: The algorithm was evaluated against a cohort of 31 participants, both healthy and diagnosed with obstructive sleep apnea. The dataset consisted of 13 female and 18 male participants between the ages of 20 and 69. The algorithm was evaluated on 7.3 hours of hand-annotated data from the cohort, or 8782 individual breaths in total. The algorithm was specifically evaluated on a dataset containing many sleep-disordered breathing events to confirm that it did not suffer in terms of accuracy when detecting breaths in the presence of sleep-disordered breathing. The algorithm was also evaluated across many participants, and we found that its accuracy was consistent across people. Source code for the algorithm was made public via an open-source Python library. RESULTS: The proposed algorithm achieved an estimated 94% accuracy when detecting breaths in respiratory signals while producing false positives that amount to only 5% of the total number of detections. The accuracy was not affected by the presence of respiratory related events, such as obstructive apneas or snoring. CONCLUSION: This work presents an automatic respiratory cycle algorithm suitable for use as an analytical tool for research based on individual breaths in sleep recordings that include respiratory inductance plethysmography.
Verbal memory is linked to average oxygen saturation during sleep, not the apnea-hypopnea index nor novel hypoxic load variables
(2024-11) Thorisdottir, K.; Hrubos-Strøm, H.; Karhu, T.; Nikkonen, S.; Dammen, T.; Nordhus, I. H.; Leppänen, T.; Jónsdóttir, María Kristín; Arnardóttir, Erna Sif; Department of Psychology; Department of Engineering
Introduction: The apnea-hypopnea index (AHI) is the current diagnostic parameter for diagnosing and estimating the severity of obstructive sleep apnea (OSA). It is, however, poorly associated with the main clinical symptom of OSA, excessive daytime sleepiness, and with the often-seen cognitive decline among OSA patients. To better evaluate OSA severity, novel hypoxic load parameters have been introduced that consider the duration and depth of oxygen saturation drops associated with apneas or hypopneas. The aim of this paper was to compare novel hypoxic load parameters and traditional OSA parameters to verbal memory and executive function in OSA patients. Method: A total of 207 adults completed a one-night polysomnography at sleep laboratory and two neuropsychological assessments, the Rey Auditory Verbal Learning Test and Stroop test. Results: Simple linear regression analyses were used to evaluate independent associations between each OSA parameter and cognitive performance. Associations were found between immediate recall and arousal index, hypoxia <90 %, average SpO2 during sleep, and DesSev100+RevSev100. Total recall was associated with all OSA parameters, and no associations were found with the Stroop test. Subsequently, sex, age, and education were included as covariates in multiple linear regression analyses for each OSA parameter and cognitive performance. The main findings of the study were that average SpO2 during sleep was a significant predictor of total recall (p < .007, β = −.188) with the regression model explaining 21.2 % of performance variation. Average SpO2 during sleep was also a significant predictor of immediate recall (p < .022, β = −.171) with the regression model explaining 11.4 % of performance variation. Neither traditional OSA parameters nor novel hypoxic load parameters predicted cognitive performance after adjustment for sex, age, and education. Conclusion: The findings validate that the AHI is not an effective indicator of cognitive performance in OSA and suggest that average oxygen saturation during sleep may be the strongest PSG predictor of cognitive decline seen in OSA. The results also underline the importance of considering age when choosing neurocognitive tests, the importance of including more than one test for each cognitive domain as most tests are not pure measures of a single cognitive factor, and the importance of including tests that cover all cognitive domains as OSA is likely to have diffuse cognitive effects.
Sequence variants influencing the regulation of serum IgG subclass levels
(2024-12) Ólafsdóttir, Þórunn Ásta; Thorleifsson, Gudmar; Lopez de Lapuente Portilla, Aitzkoa; Jonsson, Stefan; Stefánsdóttir, Lilja; Niroula, Abhishek; Jonasdottir, Aslaug; Eggertsson, Hannes P.; Halldórsson, Gísli Hreinn; Thorlacius, Gudny E.; Arnthorsson, Asgeir O.; Björnsdóttir, Unnur Steina; Asselbergs, Folkert W.; Bentlage, Arthur E.H.; Eyjolfsson, Gudmundur I.; Gudmundsdottir, Steinunn; Gunnarsdottir, Kristbjorg; Halldórsson, Bjarni Vilhjálmur; Holm, Hilma; Lúðvíksson, Björn Rúnar; Melsted, Páll; Norddahl, Gudmundur L.; Ólafsson, Ísleifur; Saevarsdottir, Saedis; Sigurdardottir, Olof; Sigurdsson, Asgeir; Temming, Robin; Önundarson, Páll Torfi; Þorsteinsdóttir, Unnur; Vidarsson, Gestur; Sulem, Patrick; Gudbjartsson, Daniel F.; Jónsdóttir, Ingileif; Nilsson, Björn; Stefánsson, Kári
Immunoglobulin G (IgG) is the main isotype of antibody in human blood. IgG consists of four subclasses (IgG1 to IgG4), encoded by separate constant region genes within the Ig heavy chain locus (IGH). Here, we report a genome-wide association study on blood IgG subclass levels. Across 4334 adults and 4571 individuals under 18 years, we discover ten new and identify four known variants at five loci influencing IgG subclass levels. These variants also affect the risk of asthma, autoimmune diseases, and blood traits. Seven variants map to the IGH locus, three to the Fcγ receptor (FCGR) locus, and two to the human leukocyte antigen (HLA) region, affecting the levels of all IgG subclasses. The most significant associations are observed between the G1m (f), G2m(n) and G3m(b*) allotypes, and IgG1, IgG2 and IgG3, respectively. Additionally, we describe selective associations with IgG4 at 16p11.2 (ITGAX) and 17q21.1 (IKZF3, ZPBP2, GSDMB, ORMDL3). Interestingly, the latter coincides with a highly pleiotropic signal where the allele associated with lower IgG4 levels protects against childhood asthma but predisposes to inflammatory bowel disease. Our results provide insight into the regulation of antibody-mediated immunity that can potentially be useful in the development of antibody based therapeutics.
Innovative Diagnostic Approaches for Predicting Knee Cartilage Degeneration in Osteoarthritis Patients : A Radiomics-Based Study
(2024-09-12) Angelone, Francesca; Ciliberti, Federica Kiyomi; Tobia, Giovanni Paolo; Jónsson, Halldór; Ponsiglione, Alfonso Maria; Gislason, Magnus Kjartan; Tortorella, Francesco; Amato, Francesco; Gargiulo, Paolo; Department of Engineering
Osteoarthritis (OA) is a common joint disease affecting people worldwide, notably impacting quality of life due to joint pain and functional limitations. This study explores the potential of radiomics — quantitative image analysis combined with machine learning — to enhance knee OA diagnosis. Using a multimodal dataset of MRI and CT scans from 138 knees, radiomic features were extracted from cartilage segments. Machine learning algorithms were employed to classify degenerated and healthy knees based on radiomic features. Feature selection, guided by correlation and importance analyses, revealed texture and shape-related features as key predictors. Robustness analysis, assessing feature stability across segmentation variations, further refined feature selection. Results demonstrate high accuracy in knee OA classification using radiomics, showcasing its potential for early disease detection and personalized treatment approaches. This work contributes to advancing OA assessment and is part of the European SINPAIN project aimed at developing new OA therapies.
Beyond pixel : Superpixel-based MRI segmentation through traditional machine learning and graph convolutional network
(2024-11) Khatun, Zakia; Jónsson, Halldór; Tsirilaki, Mariella; Maffulli, Nicola; Oliva, Francesco; Daval, Pauline; Tortorella, Francesco; Gargiulo, Paolo; Department of Engineering
Background and Objective: Tendon segmentation is crucial for studying tendon-related pathologies like tendinopathy, tendinosis, etc. This step further enables detailed analysis of specific tendon regions using automated or semi-automated methods. This study specifically aims at the segmentation of Achilles tendon, the largest tendon in the human body. Methods: This study proposes a comprehensive end-to-end tendon segmentation module composed of a preliminary superpixel-based coarse segmentation preceding the final segmentation task. The final segmentation results are obtained through two distinct approaches. In the first approach, the coarsely generated superpixels are subjected to classification using Random Forest (RF) and Support Vector Machine (SVM) classifiers to classify whether each superpixel belongs to a tendon class or not (resulting in tendon segmentation). In the second approach, the arrangements of superpixels are converted to graphs instead of being treated as conventional image grids. This classification process uses a graph-based convolutional network (GCN) to determine whether each superpixel corresponds to a tendon class or not. Results: All experiments are conducted on a custom-made ankle MRI dataset. The dataset comprises 76 subjects and is divided into two sets: one for training (Dataset 1, trained and evaluated using leave-one-group-out cross-validation) and the other as unseen test data (Dataset 2). Using our first approach, the final test AUC (Area Under the ROC Curve) scores using RF and SVM classifiers on the test data (Dataset 2) are 0.992 and 0.987, respectively, with sensitivities of 0.904 and 0.966. On the other hand, using our second approach (GCN-based node classification), the AUC score for the test set is 0.933 with a sensitivity of 0.899. Conclusions: Our proposed pipeline demonstrates the efficacy of employing superpixel generation as a coarse segmentation technique for the final tendon segmentation. Whether utilizing RF, SVM-based superpixel classification, or GCN-based classification for tendon segmentation, our system consistently achieves commendable AUC scores, especially the non-graph-based approach. Given the limited dataset, our graph-based method did not perform as well as non-graph-based superpixel classifications; however, the results obtained provide valuable insights into how well the models can distinguish between tendons and non-tendons. This opens up opportunities for further exploration and improvement.
State of art of mobility medicine : some more abstracts and evidence that the success of Pdm3 is based on extra-session relationships
(2024) Carraro, Ugo; Alberty, Marie Sophie; Anton, Stephen; Barbieri, Elena; Bersch, Ines; Bosco, Gerardo; Coraci, Daniele; Forni, Riccardo; Gargiulo, Paolo; Gentil, Paulo; Gorgey, Ashraf S.; Maccarone, Maria Chiara; Mayr, Winfried; Messina, Giuseppe; Perrin, Philippe; Pietrangelo, Tiziana; Quadrelli, Marco; Sestili, Piero; Tavian, Daniela; Tognolo, Lucrezia; Masiero, Stefano; Department of Engineering
Scientific conferences increasingly suffer from the need for short presentations in which speakers like to dwell on the details of their work. A mitigating factor is to encourage discussion and planning of collaborations by organizing small meetings in a hotel large enough to host all attendees. This extends discussions' opportunities during morning breakfasts, lunches, dinners and long evenings together. Even if the vast majority of participants will not stay for the entire duration of the Conference, the possibilities for specialists to interact with specialists who are even very distant in terms of knowledge increase enormously. In any case, the results in terms of new job opportunities for young participants outweigh the costs for the organizers. Thirty years of Padova Muscle Days offer many examples, but the authors of this report on the state of the art of Mobility Medicine testify that this also happened in the 2024 Five Days of Muscle and Mobility Medicine (2024Pdm3) hosted at the Hotel Petrarca, Thermae of Euganea Hills and Padua, Italy which is in fact a valid countermeasure to the inevitable tendencies towards hyperspecialization that the explosive increase in scientific progress brings with it.
Novel strategies for cartilage assessment, interplay between bone and muscles
(2023) Ciliberti, Federica Kiyomi; Aubonnet, Romain; Ramos, Jorgelina; Recenti, Marco; Jacob, Deborah Cecelia Rose; Guerrini, Lorena; Gíslason, Magnús Kjartan; Sigurjonsson, Olafur; Tsirilaki, Mariella; Jónsson, Halldór; Gargiulo, Paolo; Department of Engineering

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