Exploration of Three-dimensional Morphometrics of the Hip Joint and Reconstructive Technologies

This dissertation is an exploration of three-dimensional (3D) anatomy using the hip joint as the model of study. Very few studies have taken advantage of 3D modeling to assess the features of commercially available software, or to assess the validity and reliability of 3D morphometrics. This dissertation compared three reconstructive software programs to survey user appreciation concerning how 3D anatomical reconstructive software can be utilized and then established the advantages and limitations of 3D measurements in the hip joint. Three main studies are presented: the first, a comparison of three widely available 3D reconstructive software programs, Amira, OsiriX, and Mimics. This comparison used a decision matrix to outline which software is best suited for construction of 3D anatomical models, morphometric analysis, and building 3D visualization and learning tools. Mimics was the best-suited program for construction of 3D anatomical models and morphometric analysis. For creating a learning tool the results were less clear. OsiriX was very user- friendly; however, it had limited capabilities. Conversely, although Amira had endless potential and could create complex dynamic videos it had a challenging interface. Based on the overall results of study one, Mimics was used in the second and third studies to quantify 3D surface morphology of the hip joint. The second study assessed the validity and reliability of a novel 3D measurement approach of the femoral head (n=45). Study two highlighted the advantages of modeling a convex shape and the advantages of quantifying the proximal femur in 3D. This measurement approach proved to be valid and reliable. The third study assessed the validity and reliability of a similar 3D measurement approach applied to the acetabulum (n=45). This study illustrated the limitations and challenges encountered when quantifying the complex geometry of the concave acetabulum. This measurement approach was reliable, yet the differences between the digital and cadaveric measurements were large and clinically significant. The hip joint is a complex joint that benefits from 3D visualization and quantification; however, challenges surrounding measuring the acetabulum remain

Changes in the Left Atrial-Esophageal Relationship with the Insertion of An Esophageal Protective Device: A Cadaveric Imaging Study

Background: Atrial fibrillation is the most common cardiac rhythm disorder in North America and is frequently treated by a minimally invasive procedure called catheter ablation. A rare, but often fatal complication of this procedure is development of an atrial-esophageal fistula (AEF) due to the proximity of the esophagus to the left atrium (LA) of the heart. Esophageal protective devices may potentially mitigate the risk of developing an AEF but their impact on the relationship between the esophagus and LA is unknown. This study will investigate the relevant anatomical changes that occur upon insertion of an esophageal protective device. Methods: 13 fresh cadaveric torsos were scanned with and without an esophageal protective device on the computed tomography (CT) modality. The width and anterior-posterior dimension of the esophagus were measured digitally and compared between pre- and post-device insertion scans. From the scans, 3D models of the LA and esophagus were created and used for a spatial analysis of their relationship. A heatmap was generated for each LA highlighting areas of close contact with the esophagus and how they changed post-device insertion. Results: Preliminary results have indicated the width and anterior-posterior dimension of the esophagus increase significantly with the insertion of the protective device (p \u3c 0.05). Further analysis of the esophagus-left atrial distance is still ongoing. Discussion: Data from this study will provide valuable insight on changes that could be made to the device design and potentially boost its clinical efficacy and prevent AEF formation

LILRB3 (ILT5) is a myeloid cell checkpoint that elicits profound immunomodulation.

Despite advances in identifying the key immunoregulatory roles of many of the human leukocyte immunoglobulin-like receptor (LILR) family members, the function of the inhibitory molecule LILRB3 (ILT5, CD85a, LIR3) remains unclear. Studies indicate a predominant myeloid expression; however, high homology within the LILR family and a relative paucity of reagents have hindered progress toward identifying the function of this receptor. To investigate its function and potential immunomodulatory capacity, a panel of LILRB3-specific monoclonal antibodies (mAbs) was generated. LILRB3-specific mAbs bound to discrete epitopes in Ig-like domain 2 or 4. LILRB3 ligation on primary human monocytes by an agonistic mAb resulted in phenotypic and functional changes, leading to potent inhibition of immune responses in vitro, including significant reduction in T cell proliferation. Importantly, agonizing LILRB3 in humanized mice induced tolerance and permitted efficient engraftment of allogeneic cells. Our findings reveal powerful immunosuppressive functions of LILRB3 and identify it as an important myeloid checkpoint receptor

Structure-activity relationship (SAR) in monosaccharide-based Toll-like receptor 4 (TLR4) antagonists

The structure-activity relationship was investigated in a series of synthetic TLR4 antagonists formed by a glucosamine core linked to two phosphate esters and two linear carbon chains. Molecular modeling showed that the compounds with 10, 12 and 14 carbons chains are associated to higher stabilization of the MD-2/TLR4 antagonist conformation than in the case of the C16 variant. Binding experiments with human MD-2 showed that the C12 and C14 variants have higher affinity than C10, while the C16 variant did not interact with the protein. The molecules, with the exception of the C16 variant, inhibited the LPS-stimulated TLR4 signal in human and murine cells and the antagonist potency mirrored the MD-2 affinity calculated from in vitro binding experiments. FT-IR, NMR, and SAXS measurements suggested that the aggregation state in aqueous solution depends on fatty acid chains lengths and that this property can influence TLR4 activity in this series of compounds

LILRB3 (ILT5) is a myeloid cell checkpoint that elicits profound immunomodulation

Despite advances in identifying the key immunoregulatory roles of many of the human leukocyte immunoglobulin-like receptor (LILR) family members, the function of the inhibitory molecule LILRB3 (ILT5, CD85a, LIR3) remains unclear. Studies indicate a predominant myeloid expression; however, high homology within the LILR family and a relative paucity of reagents have hindered progress toward identifying the function of this receptor. To investigate its function and potential immunomodulatory capacity, a panel of LILRB3-specific monoclonal antibodies (mAbs) was generated. LILRB3-specific mAbs bound to discrete epitopes in Ig-like domain 2 or 4. LILRB3 ligation on primary human monocytes by an agonistic mAb resulted in phenotypic and functional changes, leading to potent inhibition of immune responses in vitro, including significant reduction in T cell proliferation. Importantly, agonizing LILRB3 in humanized mice induced tolerance and permitted efficient engraftment of allogeneic cells. Our findings reveal powerful immunosuppressive functions of LILRB3 and identify it as an important myeloid checkpoint receptor