Deferasirox, an iron chelator, impacts myeloid differentiation by modulating NF-kB activity via mitochondrial ROS.

The iron chelator deferasirox (DFX) is effective in the treatment of iron overload. In certain patients with myelodysplastic syndrome, DFX can also provide a dramatic therapeutic benefit, improving red blood cell production and decreasing transfusion requirements. Nuclear Factor-kappa B (NF-kB) signalling has been implicated as a potential mechanism behind this phenomenon, with studies focusing on the effect of DFX on haematopoietic progenitors. Here, we examine the phenotypic and transcriptional effects of DFX throughout myeloid cell maturation in both murine and human model systems. The effect of DFX depends on the stage of differentiation, with effects on mitochondrial reactive oxygen species (ROS) production and NF-kB pathway regulation that vary between progenitors and neutrophils. DFX triggers a greater increase in mitochondrial ROS production in neutrophils and this phenomenon is mitigated when cells are cultured in hypoxic conditions. Single-cell transcriptomic profiling revealed that DFX decreases the expression of NF-kB and MYC (c-Myc) targets in progenitors and decreases the expression of PU.1 (SPI1) gene targets in neutrophils. Together, these data suggest a role of DFX in impairing terminal maturation of band neutrophils.

Machine Learning in the Diagnosis, Management, and Care of Patients with Low Back Pain: A Scoping Review of the Literature and Future Directions.

BACKGROUND CONTEXT: Low back pain (LBP) remains the leading cause of disability globally. In recent years, machine learning (ML) has emerged as a potentially useful tool to aid the diagnosis, management, and prognostication of LBP. PURPOSE: In this review, we assess the scope of ML applications in the LBP literature and outline gaps and opportunities. STUDY DESIGN/SETTING: A scoping review was performed in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines. METHODS: Articles were extracted from the Web of Science, Scopus, PubMed, and IEEE Xplore databases. Title/abstract and full-text screening was performed by two reviewers. Data on model type, model inputs, predicted outcomes, and ML methods were collected. RESULTS: In total, 223 unique studies published between 1988-2023 were identified, with just over 50% focused on low-back-pain detection. Neural networks were used in 106 of these articles. Common inputs included patient history, demographics, and lab values (67% total). Articles published after 2010 were also likely to incorporate imaging data into their models (41.7% of articles). Of the 212 supervised learning articles identified, 168 (79.4%) mentioned use of a training or testing dataset, 116 (54.7%) utilized cross-validation, and 46 (21.7%) implemented hyperparameter optimization. Of all articles, only 8 included external validation and 9 had publicly available code. CONCLUSIONS: Despite the rapid application of ML in LBP research, a majority of articles do not follow standard ML best practices. Furthermore, over 95% of articles cannot be reproduced or authenticated due to lack of code availability. Increased collaboration and code sharing are needed to support future growth and implementation of ML in the care of patients with LBP.

Enhancing Drug Discovery and Development through the Integration of Medicinal Chemistry, Chemical Biology, and Academia-Industry Partnerships: Insights from Roche's Endocannabinoid System Projects.

The endocannabinoid system (ECS) is a critical regulatory network composed of endogenous cannabinoids (eCBs), their synthesizing and degrading enzymes, and associated receptors. It is integral to maintaining homeostasis and orchestrating key functions within the central nervous and immune systems. Given its therapeutic significance, we have launched a series of drug discovery endeavors aimed at ECS targets, including peroxisome proliferator-activated receptors (PPARs), cannabinoid receptors types 1 (CB1R) and 2 (CB2R), and monoacylglycerol lipase (MAGL), addressing a wide array of medical needs. The pursuit of new therapeutic agents has been enhanced by the creation of specialized labeled chemical probes, which aid in target localization, mechanistic studies, assay development, and the establishment of biomarkers for target engagement. By fusing medicinal chemistry with chemical biology in a comprehensive, translational end-to-end drug discovery strategy, we have expedited the development of novel therapeutics. Additionally, this strategy promises to foster highly productive partnerships between industry and academia, as will be illustrated through various examples.

Supporting transplant athletes: perspectives on delivery of a sports performance and well-being service at the British Transplant Games.

Evidence suggests that engaging in physical activity improves the mental and physical health of transplant recipients. An opportunity to be more active could be participating in the national and international network of Transplant Games. Although the literature on motivations for and the experience of taking part in the Games is available, little is known about what role applied practitioners, specifically sport and exercise psychologists could play as transplant recipients prepare and compete. This paper offers perspectives on the provision of a sports performance well-being service delivered at the British Transplant Games. The paper consists of several sections. The first offers background and how the service came into being. The second provides details of the model and philosophy that underpinned the service delivery. The third includes the trainee and exercise practitioner's casework and the challenges therein. Informed by the team's reflections and post-games survey the final section proposes recommendations for future applied sport and exercise services at this unique event.

Percutaneous lumbar interbody fusion results in less perioperative opioid usage compared to minimally invasive transforaminal lumbar interbody fusion: a single institution, multi-surgeon retrospective study.

Background: Ultra-minimally invasive percutaneous lumbar interbody fusion (percLIF) has been demonstrated to further minimize tissue trauma and has been associated with improved clinical outcomes including decreased blood loss, post-operative pain and length of stay when compared to minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) surgery. A single-institution retrospective study was conducted to investigate whether 1-level percLIF is associated with decreased narcotic consumption compared to 1-level MIS-TLIF in the first 24-hour following surgery. Methods: A retrospective study of patients undergoing either single-level percLIF or MIS-TLIF from January 2018 to December 2021. Opioid consumption in the 24-hour following surgery was converted into total morphine milligram equivalents (MME). The primary outcome used univariate and multivariate regression analysis to compare MME consumption between the MIS-TLIF and percLIF groups. Secondary outcome variables included, estimated blood loss, total intraoperative MME, MME at discharge, MME at 30 days post-op, exiting nerve root injury, post-anesthesia care unit (PACU) visual analogue scale (VAS) score at handoff, time to first ambulation, distance ambulated post-operative day one and hospital length of stay. Results: A total of 51 patients (21 percLIF vs. 30 MIS-TLIF) were included in the study. Univariate regression analysis revealed that on average patients who underwent percLIF had a 24-hour postoperative MME -50.8 mg (95% CI: -91.6, -10) lower than those who had MIS-TLIF (P=0.02). On multivariable analysis, after adjusting for sex and age, 24-hour postoperative MME closely failed to meet statistical significance (P=0.06) with an average of -40.8 mg (95% CI: -83.2, 1.6) MME in percLIF patients compared to MIS-TLIF. There was no statistically significant difference in MME between MIS-TLIF and percLIF at the time of discharge and at 30 days post-op. Conclusions: In the setting of the current opioid epidemic in the United States and increased numbers of patients undergoing lumbar interbody fusion, spine surgeons must continue to do their part helping reduce the need for opioid prescriptions for postoperative pain management. New "ultra-MIS" techniques such as percLIF allow surgeons to further decrease tissue trauma, which should lead to reduced need for post-operative narcotic requirements.

DHODH inhibition enhances the efficacy of immune checkpoint blockade by increasing cancer cell antigen presentation.

Pyrimidine nucleotide biosynthesis is a druggable metabolic dependency of cancer cells, and chemotherapy agents targeting pyrimidine metabolism are the backbone of treatment for many cancers. Dihydroorotate dehydrogenase (DHODH) is an essential enzyme in the de novo pyrimidine biosynthesis pathway that can be targeted by clinically approved inhibitors. However, despite robust preclinical anticancer efficacy, DHODH inhibitors have shown limited single-agent activity in phase 1 and 2 clinical trials. Therefore, novel combination therapy strategies are necessary to realize the potential of these drugs. To search for therapeutic vulnerabilities induced by DHODH inhibition, we examined gene expression changes in cancer cells treated with the potent and selective DHODH inhibitor brequinar (BQ). This revealed that BQ treatment causes upregulation of antigen presentation pathway genes and cell surface MHC class I expression. Mechanistic studies showed that this effect is (1) strictly dependent on pyrimidine nucleotide depletion, (2) independent of canonical antigen presentation pathway transcriptional regulators, and (3) mediated by RNA polymerase II elongation control by positive transcription elongation factor B (P-TEFb). Furthermore, BQ showed impressive single-agent efficacy in the immunocompetent B16F10 melanoma model, and combination treatment with BQ and dual immune checkpoint blockade (anti-CTLA-4 plus anti-PD-1) significantly prolonged mouse survival compared to either therapy alone. Our results have important implications for the clinical development of DHODH inhibitors and provide a rationale for combination therapy with BQ and immune checkpoint blockade.

Highly Selective Drug-Derived Fluorescent Probes for the Cannabinoid Receptor Type 1 (CB1R).

The cannabinoid receptor type 1 (CB1R) is pivotal within the endocannabinoid system regulating various signaling cascades with effects in appetite regulation, pain perception, memory formation, and thermoregulation. Still, understanding of CB1R's cellular signaling, distribution, and expression dynamics is very fragmentary. Real-time visualization of CB1R is crucial for addressing these questions. Selective drug-like CB1R ligands with a defined pharmacological profile were investigated for the construction of CB1R fluorescent probes using a reverse design-approach. A modular design concept with a diethyl glycine-based building block as the centerpiece allowed for the straightforward synthesis of novel probe candidates. Validated by computational docking studies, radioligand binding, and cAMP assay, this systematic approach allowed for the identification of novel pyrrole-based CB1R fluorescent probes. Application in fluorescence-based target-engagement studies and live cell imaging exemplify the great versatility of the tailored CB1R probes for investigating CB1R localization, trafficking, pharmacology, and its pathological implications.

Nucleotide depletion promotes cell fate transitions by inducing DNA replication stress.

Control of cellular identity requires coordination of developmental programs with environmental factors such as nutrient availability, suggesting that perturbing metabolism can alter cell state. Here, we find that nucleotide depletion and DNA replication stress drive differentiation in human and murine normal and transformed hematopoietic systems, including patient-derived acute myeloid leukemia (AML) xenografts. These cell state transitions begin during S phase and are independent of ATR/ATM checkpoint signaling, double-stranded DNA break formation, and changes in cell cycle length. In systems where differentiation is blocked by oncogenic transcription factor expression, replication stress activates primed regulatory loci and induces lineage-appropriate maturation genes despite the persistence of progenitor programs. Altering the baseline cell state by manipulating transcription factor expression causes replication stress to induce genes specific for alternative lineages. The ability of replication stress to selectively activate primed maturation programs across different contexts suggests a general mechanism by which changes in metabolism can promote lineage-appropriate cell state transitions.

Structural basis of Δ9-THC analog activity at the Cannabinoid 1 receptor.

Δ9-tetrahydrocannabinol (THC) is the principal psychoactive compound derived from the cannabis plant Cannabis sativa and approved for emetic conditions, appetite stimulation and sleep apnea relief. THC's psychoactive actions are mediated primarily by the cannabinoid receptor CB1. Here, we determine the cryo-EM structure of HU210, a THC analog and widely used tool compound, bound to CB1 and its primary transducer, Gi1. We leverage this structure for docking and 1,000 ns molecular dynamics simulations of THC and 10 structural analogs delineating their spatiotemporal interactions at the molecular level. Furthermore, we pharmacologically profile their recruitment of Gi and ß-arrestins and reversibility of binding from an active complex. By combining detailed CB1 structural information with molecular models and signaling data we uncover the differential spatiotemporal interactions these ligands make to receptors governing potency, efficacy, bias and kinetics. This may help explain the actions of abused substances, advance fundamental receptor activation studies and design better medicines.

Flipping the GPCR Switch: Structure-Based Development of Selective Cannabinoid Receptor 2 Inverse Agonists.

We report a blueprint for the rational design of G protein coupled receptor (GPCR) ligands with a tailored functional response. The present study discloses the structure-based design of cannabinoid receptor type 2 (CB2R) selective inverse agonists (S)-1 and (R)-1, which were derived from privileged agonist HU-308 by introduction of a phenyl group at the gem-dimethylheptyl side chain. Epimer (R)-1 exhibits high affinity for CB2R with Kd = 39.1 nM and serves as a platform for the synthesis of a wide variety of probes. Notably, for the first time these fluorescent probes retain their inverse agonist functionality, high affinity, and selectivity for CB2R independent of linker and fluorophore substitution. Ligands (S)-1, (R)-1, and their derivatives act as inverse agonists in CB2R-mediated cAMP as well as G protein recruitment assays and do not trigger ß-arrestin-receptor association. Furthermore, no receptor activation was detected in live cell ERK1/2 phosphorylation and Ca2+-release assays. Confocal fluorescence imaging experiments with (R)-7 (Alexa488) and (R)-9 (Alexa647) probes employing BV-2 microglial cells visualized CB2R expressed at endogenous levels. Finally, molecular dynamics simulations corroborate the initial docking data in which inverse agonists restrict movement of toggle switch Trp2586.48 and thereby stabilize CB2R in its inactive state.

Augmented Reality-based Contextual Guidance through Surgical Tool Tracking in Neurosurgery.

External ventricular drain (EVD) is a common, yet challenging neurosurgical procedure of placing a catheter into the brain ventricular system that requires prolonged training for surgeons to improve the catheter placement accuracy. In this paper, we introduce NeuroLens, an Augmented Reality (AR) system that provides neurosurgeons with guidance that aides them in completing an EVD catheter placement. NeuroLens builds on prior work in AR-assisted EVD to present a registered hologram of a patient's ventricles to the surgeons, and uniquely incorporates guidance on the EVD catheter's trajectory, angle of insertion, and distance to the target. The guidance is enabled by tracking the EVD catheter. We evaluate NeuroLens via a study with 33 medical students and 9 neurosurgeons, in which we analyzed participants' EVD catheter insertion accuracy and completion time, eye gaze patterns, and qualitative responses. Our study, in which NeuroLens was used to aid students and surgeons in inserting an EVD catheter into a realistic phantom model of a human head, demonstrated the potential of NeuroLens as a tool that will aid and educate novice neurosurgeons. On average, the use of NeuroLens improved the EVD placement accuracy of the year 1 students by 39.4%, of the year 2 -4 students by 45.7%, and of the neurosurgeons by 16.7%. Furthermore, students who focused more on NeuroLens-provided contextual guidance achieved better results, and novice surgeons improved more than the expert surgeons with NeuroLens's assistance.

Early Experience with Prone Lateral Interbody Fusion in Deformity Correction: A Single-Institution Experience.

Background/Objectives: Lateral spine surgery offers effective minimally invasive deformity correction, but traditional approaches often involve separate anterior, lateral, and posterior procedures. The prone lateral technique streamlines this process by allowing single-position access for lateral and posterior surgery, potentially benefiting from the lordosing effect of prone positioning. While previous studies have compared prone lateral to direct lateral for adult degenerative diseases, this retrospective review focuses on the outcomes of adult deformity patients undergoing prone lateral interbody fusion. Methods: Ten adult patients underwent single-position prone lateral surgery for spine deformity correction, with a mean follow-up of 18 months. Results: Results showed significant improvements: sagittal vertical axis decreased by 2.4 cm, lumbar lordosis increased by 9.1°, pelvic tilt improved by 3.3°, segmental lordosis across the fusion construct increased by 12.2°, and coronal Cobb angle improved by 6.3°. These benefits remained consistent over the follow-up period. Correlational analysis showed a positive association between improvements in PROs and SVA and SL. When compared to hybrid approaches, prone lateral yielded greater improvements in SVA. Conclusions: Prone lateral surgery demonstrated favorable outcomes with reasonable perioperative risks. However, further research comparing this technique with standard minimally invasive lateral approaches, hybrid, and open approaches is warranted for a comprehensive evaluation.

Cyclophilin A supports translation of intrinsically disordered proteins and affects haematopoietic stem cell ageing.

Loss of protein function is a driving force of ageing. We have identified peptidyl-prolyl isomerase A (PPIA or cyclophilin A) as a dominant chaperone in haematopoietic stem and progenitor cells. Depletion of PPIA accelerates stem cell ageing. We found that proteins with intrinsically disordered regions (IDRs) are frequent PPIA substrates. IDRs facilitate interactions with other proteins or nucleic acids and can trigger liquid-liquid phase separation. Over 20% of PPIA substrates are involved in the formation of supramolecular membrane-less organelles. PPIA affects regulators of stress granules (PABPC1), P-bodies (DDX6) and nucleoli (NPM1) to promote phase separation and increase cellular stress resistance. Haematopoietic stem cell ageing is associated with a post-transcriptional decrease in PPIA expression and reduced translation of IDR-rich proteins. Here we link the chaperone PPIA to the synthesis of intrinsically disordered proteins, which indicates that impaired protein interaction networks and macromolecular condensation may be potential determinants of haematopoietic stem cell ageing.

Leukemia aggressiveness is driven by chromatin remodeling and expression changes of core regulators.

Molecular mechanisms driving clonal aggressiveness in leukemia are not fully understood. We tracked and analyzed two mouse MLL-rearranged leukemic clones independently evolving towards higher aggressiveness. More aggressive subclones lost their growth differential ex vivo but restored it upon secondary transplantation, suggesting molecular memory of aggressiveness. Development of aggressiveness was associated with clone-specific gradual modulation of chromatin states and expression levels across the genome, with a surprising preferential trend of reversing the earlier changes between normal and leukemic progenitors. To focus on the core aggressiveness program, we identified genes with consistent changes of expression and chromatin marks that were maintained in vivo and ex vivo in both clones. Overexpressing selected core genes (Smad1 as aggressiveness driver, Irx5 and Plag1 as suppressors) affected leukemic progenitor growth in the predicted way and had convergent downstream effects on central transcription factors and repressive epigenetic modifiers, suggesting a broader regulatory network of leukemic aggressiveness.

Replacing hip precautions after hemiarthroplasty with a pose avoidance protocol.

AIMS: After hip arthroplasty surgery, hip precautions are often implemented to minimise the risk of dislocation, although existing evidence does not support their effectiveness. At our institution, we replaced post-operative precautions with a novel pose avoidance protocol in patients undergoing hip hemiarthroplasty for neck of femur fracture. The objectives of our study were to validate this new protocol by assessing the incidence of dislocation before and after its introduction and evaluating its impact on the length of hospital stay. METHODS: Between 20th September 2021 and 19th March 2023, 200 patients underwent 203 hip hemiarthroplasties. Hip precautions were replaced with the new pose avoidance protocol on 20th June 2022. Data were retrospectively collected and included patient demographics, Abbreviated Mental Test Score, American Society of Anaesthesiologists grade, surgical approach, prosthesis, dislocation, and mortality. RESULTS: The incidence of dislocation within 90 days after hip hemiarthroplasty decreased from seven out of 98 cases (7.1%) before 20th June 2022 to one out of 105 cases (1.0%), p-value 0.030. However, there was no significant difference in the length of stay, with a median (interquartile range) of 19 (10 - 29) days before 20th June 2022, and 16 (11 - 22) days thereafter, p-value 0.242. A multivariate logistic regression confirmed the pose avoidance protocol and the anterolateral approach to be independent negative predictors of dislocation, p-value 0.030 (Odds Ratio [OR] 0.077) and p-value 0.005 (OR 0.022), respectively. CONCLUSIONS: Hip precautions are unnecessary and potentially detrimental to patient outcomes following hemiarthroplasty. Replacing these precautions with our new pose avoidance protocol may have led to a significant reduction in dislocation rates and saved on the cost of adaptive equipment. We advocate for the anterolateral over the posterior approach in hip hemiarthroplasty to further mitigate the risk of dislocation. LEVEL OF EVIDENCE: IV.

Single-cell analyses of metastatic bone marrow in human neuroblastoma reveals microenvironmental remodeling and metastatic signature.

Neuroblastoma is an aggressive pediatric cancer with a high rate of metastasis to the BM. Despite intensive treatments including high-dose chemotherapy, the overall survival rate for children with metastatic neuroblastoma remains dismal. Understanding the cellular and molecular mechanisms of the metastatic tumor microenvironment is crucial for developing new therapies and improving clinical outcomes. Here, we used single-cell RNA-Seq to characterize immune and tumor cell alterations in neuroblastoma BM metastases by comparative analysis with patients without metastases. Our results reveal remodeling of the immune cell populations and reprogramming of gene expression profiles in the metastatic niche. In particular, within the BM metastatic niche, we observed the enrichment of immune cells, including tumor-associated neutrophils, macrophages, and exhausted T cells, as well as an increased number of Tregs and a decreased number of B cells. Furthermore, we highlighted cell communication between tumor cells and immune cell populations, and we identified prognostic markers in malignant cells that are associated with worse clinical outcomes in 3 independent neuroblastoma cohorts. Our results provide insight into the cellular, compositional, and transcriptional shifts underlying neuroblastoma BM metastases that contribute to the development of new therapeutic strategies.

Development of Potent and Selective Monoacylglycerol Lipase Inhibitors. SARs, Structural Analysis, and Biological Characterization.

New potent, selective monoacylglycerol lipase (MAGL) inhibitors based on the azetidin-2-one scaffold ((±)-5a-v, (±)-6a-j, and (±)-7a-d) were developed as irreversible ligands, as demonstrated by enzymatic and crystallographic studies for (±)-5d, (±)-5l, and (±)-5r. X-ray analyses combined with extensive computational studies allowed us to clarify the binding mode of the compounds. 5v was identified as selective for MAGL when compared with other serine hydrolases. Solubility, in vitro metabolic stability, cytotoxicity, and absence of mutagenicity were determined for selected analogues. The most promising compounds ((±)-5c, (±)-5d, and (±)-5v) were used for in vivo studies in mice, showing a decrease in MAGL activity and increased 2-arachidonoyl-sn-glycerol levels in forebrain tissue. In particular, 5v is characterized by a high eudysmic ratio and (3R,4S)-5v is one of the most potent irreversible inhibitors of h/mMAGL identified thus far. These results suggest that the new MAGL inhibitors have therapeutic potential for different central and peripheral pathologies.

Single-cell analysis of immune and stroma cell remodeling in clear cell renal cell carcinoma primary tumors and bone metastatic lesions.

BACKGROUND: Despite therapeutic advances, once a cancer has metastasized to the bone, it represents a highly morbid and lethal disease. One third of patients with advanced clear cell renal cell carcinoma (ccRCC) present with bone metastasis at the time of diagnosis. However, the bone metastatic niche in humans, including the immune and stromal microenvironments, has not been well-defined, hindering progress towards identification of therapeutic targets. METHODS: We collected fresh patient samples and performed single-cell transcriptomic profiling of solid metastatic tissue (Bone Met), liquid bone marrow at the vertebral level of spinal cord compression (Involved), and liquid bone marrow from a different vertebral body distant from the tumor site but within the surgical field (Distal), as well as bone marrow from patients undergoing hip replacement surgery (Benign). In addition, we incorporated single-cell data from primary ccRCC tumors (ccRCC Primary) for comparative analysis. RESULTS: The bone marrow of metastatic patients is immune-suppressive, featuring increased, exhausted CD8 + cytotoxic T cells, T regulatory cells, and tumor-associated macrophages (TAM) with distinct transcriptional states in metastatic lesions. Bone marrow stroma from tumor samples demonstrated a tumor-associated mesenchymal stromal cell population (TA-MSC) that appears to be supportive of epithelial-to mesenchymal transition (EMT), bone remodeling, and a cancer-associated fibroblast (CAFs) phenotype. This stromal subset is associated with poor progression-free and overall survival and also markedly upregulates bone remodeling through the dysregulation of RANK/RANKL/OPG signaling activity in bone cells, ultimately leading to bone resorption. CONCLUSIONS: These results provide a comprehensive analysis of the bone marrow niche in the setting of human metastatic cancer and highlight potential therapeutic targets for both cell populations and communication channels.

Clonal Parabacteroides from Gut Microfistulous Tracts as Transmissible Cytotoxic Succinate-Commensal Model of Crohn's Disease Complications.

Crohn's disease (CD) has been traditionally viewed as a chronic inflammatory disease that cause gut wall thickening and complications, including fistulas, by mechanisms not understood. By focusing on Parabacteroides distasonis (presumed modern succinate-producing commensal probiotic), recovered from intestinal microfistulous tracts (cavernous fistulous micropathologies CavFT proposed as intermediate between 'mucosal fissures' and 'fistulas') in two patients that required surgery to remove CD-damaged ilea, we demonstrate that such isolates exert pathogenic/pathobiont roles in mouse models of CD. Our isolates are clonally-related; potentially emerging as transmissible in the community and mice; proinflammatory and adapted to the ileum of germ-free mice prone to CD-like ileitis (SAMP1/YitFc) but not healthy mice (C57BL/6J), and cytotoxic/ATP-depleting to HoxB8-immortalized bone marrow derived myeloid cells from SAMP1/YitFc mice when concurrently exposed to succinate and extracts from CavFT-derived E. coli , but not to cells from healthy mice. With unique genomic features supporting recent genetic exchange with Bacteroides fragilis -BGF539, evidence of international presence in primarily human metagenome databases, these CavFT Pdis isolates could represent to a new opportunistic Parabacteroides species, or subspecies (' cavitamuralis' ) adapted to microfistulous niches in CD.

Accuracy of routine external ventricular drain placement following a mixed reality-guided twist-drill craniostomy.

OBJECTIVE: The traditional freehand placement of an external ventricular drain (EVD) relies on empirical craniometric landmarks to guide the craniostomy and subsequent passage of the EVD catheter. The diameter and trajectory of the craniostomy physically limit the possible trajectories that can be achieved during the passage of the catheter. In this study, the authors implemented a mixed reality-guided craniostomy procedure to evaluate the benefit of an optimally drilled craniostomy to the accurate placement of the catheter. METHODS: Optical marker-based tracking using an OptiTrack system was used to register the brain ventricular hologram and drilling guidance for craniostomy using a HoloLens 2 mixed reality headset. A patient-specific 3D-printed skull phantom embedded with intracranial camera sensors was developed to automatically calculate the EVD accuracy for evaluation. User trials consisted of one blind and one mixed reality-assisted craniostomy followed by a routine, unguided EVD catheter placement for each of two different drill bit sizes. RESULTS: A total of 49 participants were included in the study (mean age 23.4 years, 59.2% female). The mean distance from the catheter target improved from 18.6 ± 12.5 mm to 12.7 ± 11.3 mm (p = 0.0008) using mixed reality guidance for trials with a large drill bit and from 19.3 ± 12.7 mm to 10.1 ± 8.4 mm with a small drill bit (p < 0.0001). Accuracy using mixed reality was improved using a smaller diameter drill bit compared with a larger bit (p = 0.039). Overall, the majority of the participants were positive about the helpfulness of mixed reality guidance and the overall mixed reality experience. CONCLUSIONS: Appropriate indications and use cases for the application of mixed reality guidance to neurosurgical procedures remain an area of active inquiry. While prior studies have demonstrated the benefit of mixed reality-guided catheter placement using predrilled craniostomies, the authors demonstrate that real-time quantitative and visual feedback of a mixed reality-guided craniostomy procedure can independently improve procedural accuracy and represents an important tool for trainee education and eventual clinical implementation.