Synthetic MRI and MR Fingerprinting-Derived Relaxometry of Antenatal Human Brainstem Myelination: A Postmortem-Based Quantitative Imaging Study.

BACKGROUND AND PURPOSE: The radiologic evaluation of ongoing myelination is currently limited prenatally. Novel quantitative MR imaging modalities provide relaxometric properties that are linked to myelinogenesis. In this retrospective postmortem imaging study, the capability of Synthetic MR imaging and MR fingerprinting-derived relaxometry for tracking fetal myelin development was investigated. Moreover, the consistency of results for both MR approaches was analyzed. MATERIALS AND METHODS: In 26 cases, quantitative postmortem fetal brain MR data were available (gestational age range, 15 + 1 to 32 + 1; female/male ratio, 14/12). Relaxometric measurements (T1-/T2-relexation times) were determined in the medulla oblongata and the midbrain using Synthetic MR imaging/MR fingerprinting-specific postprocessing procedures (Synthetic MR imaging and MR Robust Quantitative Tool for MR fingerprinting). The Pearson correlations were applied to detect relationships between T1-relaxation times/T2-relaxation times metrics and gestational age at MR imaging. Intraclass correlation coefficients were calculated to assess the consistency of the results provided by both modalities. RESULTS: Both modalities provided quantitative data that revealed negative correlations with gestational age at MR imaging: Synthetic MR imaging-derived relaxation times (medulla oblongata [r = -0.459; P = .021]; midbrain [r = -0.413; P = .040]), T2-relaxation times (medulla oblongata [r = -0.625; P < .001]; midbrain [r = -0.571; P = .003]), and MR fingerprinting-derived T1-relaxation times (medulla oblongata [r = -0.433; P = .035]; midbrain [r = -0.386; P = .062]), and T2-relaxation times (medulla oblongata [r =-0.883; P < .001]; midbrain [r = -0.890; P < .001]).The intraclass correlation coefficient analysis for result consistency between both MR approaches ranged between 0.661 (95% CI, 0.351-0.841) (T2-relaxation times: medulla oblongata) and 0.920 (95% CI, 0.82-0.965) (T1-relaxation times: midbrain). CONCLUSIONS: There is a good-to-excellent consistency between postmortem Synthetic MR imaging and MR fingerprinting myelin quantifications in fetal brains older than 15 + 1 gestational age. The strong correlations between quantitative myelin metrics and gestational age indicate the potential of quantitative MR imaging to identify delayed or abnormal states of myelination at prenatal stages of cerebral development.

Assembly of respiratory syncytial virus matrix protein lattice and its coordination with fusion glycoprotein trimers.

Respiratory syncytial virus (RSV) is an enveloped, filamentous, negative-strand RNA virus that causes significant respiratory illness worldwide. RSV vaccines are available, however there is still significant need for research to support the development of vaccines and therapeutics against RSV and related Mononegavirales viruses. Individual virions vary in size, with an average diameter of ~130 nm and ranging from ~500 nm to over 10 µm in length. Though the general arrangement of structural proteins in virions is known, we use cryo-electron tomography and sub-tomogram averaging to determine the molecular organization of RSV structural proteins. We show that the peripheral membrane-associated RSV matrix (M) protein is arranged in a packed helical-like lattice of M-dimers. We report that RSV F glycoprotein is frequently observed as pairs of trimers oriented in an anti-parallel conformation to support potential interactions between trimers. Our sub-tomogram averages indicate the positioning of F-trimer pairs is correlated with the underlying M lattice. These results provide insight into RSV virion organization and may aid in the development of RSV vaccines and anti-viral targets.

Changes in the gut microbiota of pseudoxanthoma elasticum patients.

OBJECTIVE: Pseudoxanthoma elasticum (PXE) is a rare autosomal disorder with a variable phenotype that may be modulated by environmental factors. Plasma vitamin K (VK) levels may be involved in the ectopic calcification process observed in PXE. Since VK2 is predominantly produced by the gut microbiota, we hypothesized that changes in the gut microbiota of PXE patients might exacerbate the calcification process and disease symptoms. METHODS: Twenty PXE patients were included in the study and 60 gut microbiota profiles from the Biofortis laboratory database were used as controls. RESULTS: The Rhodospirillaceae family was more abundant in the PXE group while the Sphingomonadaceae family was more abundant in the control group. In a PXE severity subgroup analysis, microbiota dispersion was lower in "severe" than in "non-severe" patients, which was confirmed by permutation multivariate analysis of variance at the phylum, family and genus ranks. However, no significant association was found in a model incorporating relative abundance of bacterial families, severity score, and different blood and fecal VK species. CONCLUSION: These results suggest slight compositional changes in the gut microbiota of PXE patients. Further studies are needed to substantiate their impact on VK metabolism and the calcification process.

[Assessment tool's validation study for a simulation-based skin suturing skill]. / Étude de validation d'une grille d'évaluation d'un exercice de suture cutanée en simulation.

CONTEXT: Health simulation is a recognized educational method for teaching and validating surgical procedural skills. The latter requires the development of adapted assessment tools, reaching different validity criteria. The aim of this study was to validate a multimodal assessment tool for a complex skin suturing exercise, combining a manual knot, an intradermal linear suturing and a needle holder tied knot. METHODOLOGY: The suturing exercise was realized on a synthetic skin model by voluntary participants after having obtained their written consent, including 9 postgraduate medical students, 40 surgical residents of different levels of experience, and a group of 9 senior surgeons. The multimodal assessment tool (MAT) combined a checklist, a speed score and a global rating scale. Each exercise was scored by two evaluators. Medical students' performances were filmed anonymously so that they could be scored iteratively. Content validity was tested through a satisfaction questionnaire randomly completed by participants. RESULTS: The MAT was considered relevant or very relevant by 98% of the participants, with a better appreciation for the checklist than for the global rating scale. Internal consistency was strong with a Cronbach α coefficient at 0.78, and a good correlation between the results of the checklist and the global rating scale (r=0.79, P<0.0001). The MAT showed continuous improvement in mean scores from 34.4±3.6 for novices to 47.4±2.5/50 points for experts, passing through three intermediate levels groups, and allowed for significant discrimination between groups. The MAT was reliable, with a coefficient of correlation set at 0.88 for intra-observer reliability, and 0.72 for inter-observer reliability. On sub score analysis, the global rating scale and the speed score better discriminated between groups than the checklist, the latter moreover showing slightly lower reliability than the global rating scale. CONCLUSION: Despite its banality in any surgeon's practice and the fact that it is taught from the 2nd cycle of medical studies, suturing and its technical components have rarely been the subject of publications dedicated to the validation of specific assessment tools. Hence, this work on the MAT and its sub scores made it possible to validate them on many validity and reliability criteria. They can therefore be proposed to surgical teachers for evaluating a complex suturing exercise, with a checklist that is easier to use even for novices and a global rating scale showing better discrimination capacity.

Thymic epithelial organoids mediate T cell development.

Although the advent of organoids opened unprecedented perspectives for basic and translational research, immune system-related organoids remain largely underdeveloped. Here we established organoids from the thymus, the lymphoid organ responsible for T cell development. We identified conditions enabling thymic epithelial progenitor cell proliferation and development into organoids with diverse cell populations and transcriptional profiles resembling in vivo thymic epithelial cells (TECs) more closely than traditional TEC cultures. Contrary to these two-dimensional cultures, thymic epithelial organoids maintained thymus functionality in vitro and mediated physiological T cell development upon reaggregation with T cell progenitors. The reaggregates showed in vivo-like epithelial diversity and ability to attract T cell progenitors. Thymic epithelial organoids are the first organoids originating from the stromal compartment of a lymphoid organ. They provide new opportunities to study TEC biology and T cell development in vitro, paving the way for future thymic regeneration strategies in ageing or acute injuries.

A Bioinformatically Initiated Approach to Evaluate GATA1 Regulatory Regions in Samples with Weak D, Del, or D- Phenotypes Despite Normal RHD Exons.

Introduction: With over 360 blood group antigens in systems recognized, there are antigens, such as RhD, which demonstrate a quantitative reduction in antigen expression due to nucleotide variants in the non-coding region of the gene that result in aberrant splicing or a regulatory mechanism. This study aimed to evaluate bioinformatically predicted GATA1-binding regulatory motifs in the RHD gene for samples presenting with weak or apparently negative RhD antigen expression but showing normal RHD exons. Methods: Publicly available open chromatin region data were overlayed with GATA1 motif candidates in RHD. Genomic DNA from weak D, Del or D- samples with normal RHD exons (n = 13) was used to confirm RHD zygosity by quantitative PCR. Then, RHD promoter, intron 1, and intron 2 regions were amplified for Sanger sequencing to detect potential disruptions in the GATA1 motif candidates. Electrophoretic mobility shift assay (EMSA) was performed to assess GATA1-binding. Luciferase assays were used to assess transcriptional activity. Results: Bioinformatic analysis identified five of six GATA1 motif candidates in the promoter, intron 1 and intron 2 for investigation in the samples. Luciferase assays showed an enhancement in transcription for GATA1 motifs in intron 1 and for intron 2 only when the R 2 haplotype variant (rs675072G>A) was present. GATA1 motifs were intact in 12 of 13 samples. For one sample with a Del phenotype, a novel RHD c.1-110A>C variant disrupted the GATA1 motif in the promoter which was supported by a lack of a GATA1 supershift in the EMSA and 73% transcriptional activity in the luciferase assay. Two samples were D+/D- chimeras. Conclusion: The bioinformatic predictions enabled the identification of a novel DEL allele, RHD c.1-110A>C, which disrupted the GATA1 motif in the proximal promoter. Although the majority of the samples investigated here remain unexplained, we provide GATA1 targets which may benefit future RHD regulatory investigations.

Patient-specific 3D in vitro modeling and fluid dynamic analysis of primary pulmonary vein stenosis.

Introduction: Primary pulmonary vein stenosis (PVS) is a rare congenital heart disease that proves to be a clinical challenge due to the rapidly progressive disease course and high rates of treatment complications. PVS intervention is frequently faced with in-stent restenosis and persistent disease progression despite initial venous recanalization with balloon angioplasty or stenting. Alterations in wall shear stress (WSS) have been previously associated with neointimal hyperplasia and venous stenosis underlying PVS progression. Thus, the development of patient-specific three-dimensional (3D) in vitro models is needed to further investigate the biomechanical outcomes of endovascular and surgical interventions. Methods: In this study, deidentified computed tomography images from three patients were segmented to generate perfusable phantom models of pulmonary veins before and after catheterization. These 3D reconstructions were 3D printed using a clear resin ink and used in a benchtop experimental setup. Computational fluid dynamic (CFD) analysis was performed on models in silico utilizing Doppler echocardiography data to represent the in vivo flow conditions at the inlets. Particle image velocimetry was conducted using the benchtop perfusion setup to analyze WSS and velocity profiles and the results were compared with those predicted by the CFD model. Results: Our findings indicated areas of undesirable alterations in WSS before and after catheterization, in comparison with the published baseline levels in the healthy in vivo tissues that may lead to regional disease progression. Discussion: The established patient-specific 3D in vitro models and the developed in vitro-in silico platform demonstrate great promise to refine interventional approaches and mitigate complications in treating patients with primary PVS.

Patient-derived mini-colons enable long-term modeling of tumor-microenvironment complexity.

Existing organoid models fall short of fully capturing the complexity of cancer because they lack sufficient multicellular diversity, tissue-level organization, biological durability and experimental flexibility. Thus, many multifactorial cancer processes, especially those involving the tumor microenvironment, are difficult to study ex vivo. To overcome these limitations, we herein implemented tissue-engineering and microfabrication technologies to develop topobiologically complex, patient-specific cancer avatars. Focusing on colorectal cancer, we generated miniature tissues consisting of long-lived gut-shaped human colon epithelia ('mini-colons') that stably integrate cancer cells and their native tumor microenvironment in a format optimized for real-time, high-resolution evaluation of cellular dynamics. We demonstrate the potential of this system through several applications: a comprehensive evaluation of drug effectivity, toxicity and resistance in anticancer therapies; the discovery of a mechanism triggered by cancer-associated fibroblasts that drives cancer invasion; and the identification of immunomodulatory interactions among different components of the tumor microenvironment. Similar approaches should be feasible for diverse tumor types.

Self-Assembled Fibroblast Growth Factor Nanoparticles as a Therapeutic for Oxidant-Induced Neuronal and Skin Cell Injury.

Traumatic brain injury (TBI) and spinal cord injury (SCI) are neurological conditions that result from immediate mechanical injury, as well as delayed injury caused by local inflammation. Furthermore, TBI and SCI often lead to secondary complications, including pressure wounds of the skin, which can heal slowly and are prone to infection. Pressure wounds are localized areas of damaged tissue caused by prolonged pressure on the skin due to immobility and loss of neurological sensation. With the aim to ameliorate these symptoms, we investigated whether fibroblast growth factors 2 (FGF-2) could contribute to recovery. FGF-2 plays a significant role in both neurogenesis and skin wound healing. We developed a recombinant fusion protein containing FGF-2 linked to elastin-like polypeptides (FGF-ELP) that spontaneously self-assembles into nanoparticles at around 33 °C. The nanoparticle's size was ranging between 220 and 250 nm in diameter at 2 µM. We tested this construct for its ability to address neuronal and skin cell injuries. Hydrogen peroxide was used to induce oxidant-mediated injury on cultured neuronal cells to mimic the impact of reactive oxidants released during the inflammatory response in vivo. We found that FGF-ELP nanoparticles protected against hydrogen peroxide-mediated injury and promoted neurite outgrowth. In the skin cell models, cells were depleted from serum to mimic the reduced levels of nutrients and growth factors in chronic skin wounds. FGF-ELP increased the proliferation and migration of human keratinocytes, fibroblasts, and endothelial cells. FGF-ELP is, therefore, a potentially useful agent to provide both neuroprotection and promotion of cellular processes involved in skin wound healing.

Active Site Characterization of a Campylobacter jejuni Nitrate Reductase Variant Provides Insight into the Enzyme Mechanism.

Mo K-edge X-ray absorption spectroscopy (XAS) is used to probe the structure of wild-type Campylobacter jejuni nitrate reductase NapA and the C176A variant. The results of extended X-ray absorption fine structure (EXAFS) experiments on wt NapA support an oxidized Mo(VI) hexacoordinate active site coordinated by a single terminal oxo donor, four sulfur atoms from two separate pyranopterin dithiolene ligands, and an additional S atom from a conserved cysteine amino acid residue. We found no evidence of a terminal sulfido ligand in wt NapA. EXAFS analysis shows the C176A active site to be a 6-coordinate structure, and this is supported by EPR studies on C176A and small molecule analogs of Mo(V) enzyme forms. The SCys is replaced by a hydroxide or water ligand in C176A, and we find no evidence of a coordinated sulfhydryl (SH) ligand. Kinetic studies show that this variant has completely lost its catalytic activity toward nitrate. Taken together, the results support a critical role for the conserved C176 in catalysis and an oxygen atom transfer mechanism for the catalytic reduction of nitrate to nitrite that does not employ a terminal sulfido ligand in the catalytic cycle.

Artificial intelligence coronary computed tomography, coronary computed tomography angiography using fractional flow reserve, and physician visual interpretation in the per-vessel prediction of abnormal invasive adenosine fractional flow reserve.

Aims: A comparison of diagnostic performance comparing AI-QCTISCHEMIA, coronary computed tomography angiography using fractional flow reserve (CT-FFR), and physician visual interpretation on the prediction of invasive adenosine FFR have not been evaluated. Furthermore, the coronary plaque characteristics impacting these tests have not been assessed. Methods and results: In a single centre, 43-month retrospective review of 442 patients referred for coronary computed tomography angiography and CT-FFR, 44 patients with CT-FFR had 54 vessels assessed using intracoronary adenosine FFR within 60 days. A comparison of the diagnostic performance among these three techniques for the prediction of FFR ≤ 0.80 was reported. The mean age of the study population was 65 years, 76.9% were male, and the median coronary artery calcium was 654. When analysing the per-vessel ischaemia prediction, AI-QCTISCHEMIA had greater specificity, positive predictive value (PPV), diagnostic accuracy, and area under the curve (AUC) vs. CT-FFR and physician visual interpretation CAD-RADS. The AUC for AI-QCTISCHEMIA was 0.91 vs. 0.76 for CT-FFR and 0.62 for CAD-RADS ≥ 3. Plaque characteristics that were different in false positive vs. true positive cases for AI-QCTISCHEMIA were max stenosis diameter % (54% vs. 67%, P < 0.01); for CT-FFR were maximum stenosis diameter % (40% vs. 65%, P < 0.001), total non-calcified plaque (9% vs. 13%, P < 0.01); and for physician visual interpretation CAD-RADS ≥ 3 were total non-calcified plaque (8% vs. 12%, P < 0.01), lumen volume (681 vs. 510 mm3, P = 0.02), maximum stenosis diameter % (40% vs. 62%, P < 0.001), total plaque (19% vs. 33%, P = 0.002), and total calcified plaque (11% vs. 22%, P = 0.003). Conclusion: Regarding per-vessel prediction of FFR ≤ 0.8, AI-QCTISCHEMIA revealed greater specificity, PPV, accuracy, and AUC vs. CT-FFR and physician visual interpretation CAD-RADS ≥ 3.

Proceedings of the dengue endgame summit: Imagining a world with dengue control.

The first dengue "endgame" summit was held in Syracuse, NY over August 9 and 10, 2023. Organized and hosted by the Institute for Global Health and Translational Sciences at SUNY Upstate Medical University, the gathering brought together researchers, clinicians, drug and vaccine developers, government officials, and other key stakeholders in the dengue field for a highly collaborative and discussion-oriented event. The objective of the gathering was to discuss the current state of dengue around the world, what dengue "control" might look like, and what a potential roadmap might look like to achieve functional dengue control. Over the course of 7 sessions, speakers with a diverse array of expertise highlighted both current and historic challenges associated with dengue control, the state of dengue countermeasure development and deployment, as well as fundamental virologic, immunologic, and medical barriers to achieving dengue control. While sustained eradication of dengue was considered challenging, attendees were optimistic that significant reduction in the burden of dengue can be achieved by integration of vector control with effective application of therapeutics and vaccines.

Neuronal Ceroid Lipofuscinosis in a Mixed-Breed Dog with a Splice Site Variant in CLN6.

A 23-month-old neutered male dog of unknown ancestry presented with a history of progressive neurological signs that included anxiety, cognitive impairment, tremors, seizure activity, ataxia, and pronounced visual impairment. The clinical signs were accompanied by global brain atrophy. Due to progression in the severity of disease signs, the dog was euthanized at 26 months of age. An examination of the tissues collected at necropsy revealed dramatic intracellular accumulations of autofluorescent inclusions in the brain, retina, and cardiac muscle. The inclusions were immunopositive for subunit c of mitochondrial ATP synthase, and their ultrastructural appearances were similar to those of lysosomal storage bodies that accumulate in some neuronal ceroid lipofuscinosis (NCL) diseases. The dog also exhibited widespread neuroinflammation. Based on these findings, the dog was deemed likely to have suffered from a form of NCL. A whole genome sequence analysis of the proband's DNA revealed a homozygous C to T substitution that altered the intron 3-exon 4 splice site of CLN6. Other mutations in CLN6 cause NCL diseases in humans and animals, including dogs. The CLN6 protein was undetectable with immunolabeling in the tissues of the proband. Based on the clinical history, fluorescence and electron-microscopy, immunohistochemistry, and molecular genetic findings, the disorder in this dog was classified as an NCL resulting from the absence of the CLN6 protein. Screening the dog's genome for a panel of breed-specific polymorphisms indicated that its ancestry included numerous breeds, with no single breed predominating. This suggests that the CLN6 disease variant is likely to be present in other mixed-breed dogs and at least some ancestral breeds, although it is likely to be rare since other cases have not been reported to date.

Extended supercooled storage of red blood cells.

Red blood cell (RBC) transfusions facilitate many life-saving acute and chronic interventions. Transfusions are enabled through the gold-standard hypothermic storage of RBCs. Today, the demand for RBC units is unfulfilled, partially due to the limited storage time, 6 weeks, in hypothermic storage. This time limit stems from high metabolism-driven storage lesions at +1-6 °C. A recent and promising alternative to hypothermic storage is the supercooled storage of RBCs at subzero temperatures, pioneered by our group. Here, we report on long-term supercooled storage of human RBCs at physiological hematocrit levels for up to 23 weeks. Specifically, we assess hypothermic RBC additive solutions for their ability to sustain supercooled storage. We find that a commercially formulated next-generation solution (Erythro-Sol 5) enables the best storage performance and can form the basis for further improvements to supercooled storage. Our analyses indicate that oxidative stress is a prominent time- and temperature-dependent injury during supercooled storage. Thus, we report on improved supercooled storage of RBCs at -5 °C by supplementing Erythro-Sol 5 with the exogenous antioxidants, resveratrol, serotonin, melatonin, and Trolox. Overall, this study shows the long-term preservation potential of supercooled storage of RBCs and establishes a foundation for further improvement toward clinical translation.

SMIM1 absence is associated with reduced energy expenditure and excess weight.

BACKGROUND: Obesity rates have nearly tripled in the past 50 years, and by 2030 more than 1 billion individuals worldwide are projected to be obese. This creates a significant economic strain due to the associated non-communicable diseases. The root cause is an energy expenditure imbalance, owing to an interplay of lifestyle, environmental, and genetic factors. Obesity has a polygenic genetic architecture; however, single genetic variants with large effect size are etiological in a minority of cases. These variants allowed the discovery of novel genes and biology relevant to weight regulation and ultimately led to the development of novel specific treatments. METHODS: We used a case-control approach to determine metabolic differences between individuals homozygous for a loss-of-function genetic variant in the small integral membrane protein 1 (SMIM1) and the general population, leveraging data from five cohorts. Metabolic characterization of SMIM1-/- individuals was performed using plasma biochemistry, calorimetric chamber, and DXA scan. FINDINGS: We found that individuals homozygous for a loss-of-function genetic variant in SMIM1 gene, underlying the blood group Vel, display excess body weight, dyslipidemia, altered leptin to adiponectin ratio, increased liver enzymes, and lower thyroid hormone levels. This was accompanied by a reduction in resting energy expenditure. CONCLUSION: This research identified a novel genetic predisposition to being overweight or obese. It highlights the need to investigate the genetic causes of obesity to select the most appropriate treatment given the large cost disparity between them. FUNDING: This work was funded by the National Institute of Health Research, British Heart Foundation, and NHS Blood and Transplant.

Embedded 3D printing of UV-curable thermosetting composites with continuous fiber.

Extrusion-based 3D printing methods with in-nozzle impregnation mechanisms have been extensively employed in the fabrication of continuous fiber composites. This study presents an innovative embedded 3D printing technique that addresses significant challenges associated with existing methods. The technique utilizes a deposition nozzle to precisely write continuous fibers below the resin. A laser beam is directed onto the resin surface, which simultaneously cures the resin around the fiber bundle. The printing method demonstrates its advantages in producing high-quality composite samples with well-aligned fibers, minimized void density, and outstanding mechanical properties. More importantly, it introduces several capabilities that are highly desirable in the fabrication of contemporary composites, but unattainable with existing methods, including the dynamic control of fiber volume fractions and the ability to change matrix materials during printing. Furthermore, it enables the printing of filaments along curved pathways and printing of overhanging filaments for hollow features without support materials. The developed printing method exhibits versatility in working with different commercially available feedstock resins and reinforcement fibers. It is anticipated to be an impactful approach for the future development of thermosetting composites with diverse structural or multifunctional applications.

Does the Paraphilia Scale Work for Everyone? Confirmatory Factor Analysis and Measurement Invariance Across Gender and Sexual Orientation Groups.

We conducted three studies to examine the factor structure and measurement invariance of the Paraphilia Scale, a measure of paraphilic interests used in multiple studies. In the first study, we conducted a confirmatory factor analysis (CFA) testing different a priori models with a community sample of 1,040 adults previously reported by Seto et al. (2021), and found support for a hierarchical four-factor model: An agonistic continuum involving coercion or physical pain (biastophilia, sexual sadism, masochism), chronophilias (pedophilia, hebephilia), courtship disorders (voyeurism, exhibitionism, and frotteurism), and fetishism (object fetishism, transvestic fetishism, urophilia-coprophilia). This factor structure was replicated in a second study comprising a combined sample of 400 mTurk participants and 870 university students. The third study analyzed the community sample and found evidence of configural invariance but not scalar or metric invariance across gender (man or woman) and sexual orientation for gender (heterosexual or other sexual orientation). This indicates that the factor structure of the Paraphilia Scale is robust for gender and sexual orientation for gender, but factor loadings differ across these groups, as do the loadings of individual items on the four factors. Implications for research on gender and sexual orientation differences in paraphilic interests are discussed.