Insertion Orientation Research Articles

IStent insertion orientation and impact on trabecular meshwork motion resolved by optical coherence tomography imaging.

The iStent is a popular device designed for glaucoma treatment, functioning by creating an artificial fluid pathway in the trabecular meshwork (TM) to drain aqueous humor. The assessment of iStent implantation surgery is clinically important. However, current tools offer limited information. We aim to develop innovative assessment strategies for iStent implantation using optical coherence tomography (OCT) to evaluate the position and orientation of the iStent and its biomechanical impact on outflow system dynamics. We examined four iStents in the two eyes of a glaucoma patient. Three-dimensional (3D) OCT structural imaging was conducted for each iStent, and a semi-automated algorithm was developed for iStent segmentation and visualization, allowing precise measurement of position and orientation. In addition, phase-sensitive OCT (PhS-OCT) imaging was introduced to measure the biomechanical impact of the iStent on the outflow system quantified by cumulative displacement (CDisp) of pulse-dependent trabecular TM motion. The 3D structural image processed by our algorithm definitively resolved the position and orientation of the iStent in the anterior segment, revealing substantial variations in relevant parameters. PhS-OCT imaging demonstrated significantly higher CDisp in the regions between two iStents compared to locations distant from the iStents in both OD ( ) and OS ( ). Our proposed structural imaging technique improved the characterization of the iStent's placement. The imaging results revealed inherent challenges in achieving precise control of iStent insertion. Furthermore, PhS-OCT imaging unveiled potential biomechanical alterations induced by the iStent. This unique methodology shows potential as a valuable clinical tool for evaluating iStent implantation.

Neo-Commissural Alignment by Withdrawing and Readvancing the Delivery System during Transcatheter Aortic Valve Replacement with Self-Expanding Prosthesis.

To investigate the feasibility of obtaining neo-commissural alignment by withdrawing and readvancing the delivery system during transcatheter aortic valve replacement (TAVR) with self-expanding prosthesis. TAVR was performed in five patients with severe aortic valve stenosis by the femoral approach. The delivery catheter was withdrawn and readvanced with the opposite orientation when the Venus-A plus transcatheter heart valve (THV) centre marker was found to be overlapped with or close to the left marker at the aortic annulus level on the fluoroscopic image at the projection of the right and left coronary cusps superimposing. Neo-commissural alignment was evaluated by comparing the aortic computed tomography before TAVR with it after TAVR. The THV centre marker was overlapped with or close to the right marker at the aortic annulus level on the fluoroscopic image at the projection of the right and left coronary cusps superimposed in all the present five patients after withdrawing and readvancing the delivery system. The commissural angle deviation before vs. post TAVR was 12.3° ± 7.0°. Three of five patients had neo-commissural alignment. Two of the five patients had mild neo-commissural misalignment. It is possible to obtain the neo-commissural alignment by controlling delivery catheter insertion orientation using the markers on the inflow of the Venus-A plus valve.

Forward Genetic Screen Implicates Drivers of Leukemic Progression in a Novel Model of Trp53 R270H myelodysplastic Syndrome

Myelodysplastic syndrome (MDS) is characterized by bone marrow failure and a highly variable clinical course. The most catastrophic complication of MDS is transformation to secondary acute myeloid leukemia (sAML). Notably, mutations in TP53 confer the single highest risk of transformation to sAML and death. However, some patients with TP53 mutated MDS do not develop sAML, suggesting that additional genetic events cooperate with TP53 mutations to transform MDS to sAML. Understanding the mechanisms of transformation of MDS to sAML could provide targets for therapeutic intervention. To model the genetics of MDS, we crossed mice bearing Trp53 R270H ( Trp53 is the murine TP53 gene) and deletion of genes syntenic with human chromosome 5q (del(5q)). To discover how additional mutations contribute to disease progression, we utilized Sleeping Beauty (SB) transposon mutagenesis in Trp53 R270H/del(5q) mice. SB transposase mobilized SB mutagenic T2/Onc transposons which randomly insert within the genome. T2/Onc transposons are designed to induce gain or loss of function alterations depending on the site and orientation of insertion with respect to targeted genes. We used the Mx1-Cre transgene to activate SB transposase and T2/Onc transposition in hematopoietic progenitors. Trp53 R270H anddel(5q)(or cytogenetically normal, CN) mice were crossed to SB mice to generate donor mice of the following genotypes: Trp53 R270H/del(5q)/ SB, Trp53 R270H/CN /SB, Trp53 WT/del(5q)/ SB, Trp53 WT/CN/ SB mice, and mice without SB transposition, (no transposition, NT: Trp53 R270H/del(5q) /NT). Bone marrow cells were transplanted into recipients, and SB insertional mutagenesis was activated using pI-pC to activate Cre. Mice receiving Trp53 WT/CN/ SB bone marrow developed more frequent T-cell leukemia (n=3/10) than myeloid leukemia (n=1/10). In contrast, mice receiving Trp53 R270H/del(5q)/SB and Trp53 R270H/CN /SB bone marrow developed predominantly myeloid leukemia (n=14/28) more commonly than T-cell leukemia (1/28). Mixed phenotype leukemia was seen in 7/28 of these mice. Together, these data demonstrate a strong bias towards myeloid disease in SB-mutagenized Trp53 R270H bone marrow. To identify genes with SB insertions, we performed RNA sequencing to detect SB T2/Onc transposon-endogenous genefusion transcripts. Among Trp53 WT/CN/ SB leukemias, the most common recurrent SB fusions involved Notch1 and Ikzf1 as has previously reported for SB-associated T-cell leukemias . Among Trp53 R270H/del(5q)/SB and Trp53 R270H/CN /SB leukemias, the most common recurrent SB-fusions involved Erg, Eras and Il2rb with Erg fusions detected 85% of Trp53 R270H leukemias (n=17/20). SB inserted upstream of Erg promoter indicating that these fusions likely upregulate expression of Erg. Indeed, Erg levels are significantly higher in leukemias that express SB-Erg fusions relative to leukemias that do not (p<0.0023). ERG is not recurrently mutated in human AML, but the ERG gene locus is commonly amplified, especially TP53 mutant AML. ERG is known to support normal hematopoietic stem cell self-renewal. Notably, Erg-insertions were also detected in a model of MDS expressing stabilized cyclin E with SB-mediated progression to erythroleukemia (Loeb 2019). Using gene set enrichment analysis, we found that hematopoietic stem cell and leukemic stem cell signatures are enriched in Erg-SB fusion leukemias. In our analyses of two independent data sets (TCGA and BEAT AML), stem cell signatures are also among the most highly enriched pathways in human AMLs expressing high ERG levels. Furthermore, in a human AML single cell RNA sequencing dataset (van Galen 2019), we found that ERG expression is highest in AML cells with the most immature stem and progenitor-like features. Together, these findings implicate a role for ERG as a driver of progression of MDS to AML by enhancing aberrant self-renewal. In summary, we present a novel murine model of Trp53/del(5q) MDS. In this model, Erg upregulation is associated with progression to AML and upregulation of leukemia stem cell gene expression profiles. These data implicate ERG as a major contributor to progression of MDS to secondary AML in the setting of mutant p53. Understanding the mechanisms of disease progression and self-renewal in myeloid malignancies with p53 mutations is critical to define effective therapeutic strategies in these rapidly fatal, treatment resistant diseases.

Robotic system for nasopharyngeal swab sampling based on remote center of motion mechanism.

In this study, a robotic system is proposed for nasopharyngeal (NP) swab sampling with high safety and efficiency. Most existing swab-sampling robots have more than six degrees of freedom (DOFs). However, not all six DOFs are necessarily required for NP swab sampling. A high number of DOFs can cause safety problems, such as collisions between the robot and patient. We developed a new type of robot with four DOFs for NP swab sampling that consists of a two DOFs remote center of motion (RCM) mechanism, a two DOFs insertion mechanism, and a nostril support unit. With the nostril support unit, the robot no longer needs to adjust the insertion position of the swab. The proposed robot enables the insertion orientation and depth to be adjusted according to different postures or facial shapes of the subject. For intuitive and precise remote control of the robot, a dedicated master device for the RCM and a visual feedback system were developed. The effectiveness of the robotic system was demonstrated by repeatability, RCM accuracy, tracking accuracy, and in vitro phantom experiments. The average tracking error between the master device and the robot was less than 2mm. The contact force exerted on the swab prior to reaching the nasopharynx was less than 0.04 N, irrespective of the phantom's pose. This study confirmed that the RCM-based robotic system is effective and safe for NP swab sampling while using minimal DOFs.

Sagittal Orientation and Variabilities of the Anatomical Insertional Footprint of the Achilles Tendon: A Cadaveric Study

Category: Hindfoot; Sports Introduction/Purpose: New surgical techniques for Achilles tendon insertional pathology are evolving rapidly. Whether via open surgery, minimally invasive, or endoscopic approaches, more information about the Achilles' insertional footprint is needed to help surgeons with decision making. This study investigated the footprints of the Achilles insertion in sagittal orientation to delineate the anatomical landmarks, safe zones for bone resection3-down surgeries in treating insertional Achilles tendinopathies. Methods: Twenty fresh frozen cadavers were selected excluding insertional Achilles tendon pathology on lateral view x-rays. The calcanei were dissected maintaining the Achilles tendon insertion intact. Dimensions of the posterior tuberosity were recorded and marked to plan for three sagittal cuts (medial, middle, and lateral) (Fig 1 A). Using an oscillating saw (Fig 1 B.), the posterior tuberosity was cut into four pieces (Fig 1 C,E). A trapezoid shape (Fig 1 D) was reconstructed demonstrating relative location of the footprints of the Achilles insertion compared to the boundaries of the tuberosity on each piece (A, most superior point in the posterior tuberosity; B, most superior point in the Achilles insertion; C, most inferior point in the Achilles insertion; D, most inferior point in the posterior tuberosity). Data regarding footprints of the Achilles tendon insertion in the sagittal orientation was analyzed and compared within each trapezoid region and among different regions. Results: AB (calcaneal tuberosity tip to the upper limit of the Achilles insertion) was shortest at the medial cut (9.35mm) and longest at the lateral cut (12.15mm). However, the tendon thickness at the insertion (the distance from the proximal to the distal limits) represented by BC was shortest at the lateral cut (13.19mm) and longest at the middle cut (14.04mm). AD, the distance from the highest to the lowest point of the calcaneal tuberosity, was the longest at the middle cut (41.20mm). AB:BC ratio was highest at the lateral cut and lowest at the medial cut, indicating the safe amount of bone to be resected at the Achilles insertion. Tendon thickness relative to the whole calcaneal tuberosity (BC:CD) was highest at the medial wall (Table1). Conclusion: The sagittal orientation and variability of the Achilles tendon insertion is an under-studied topic in the literature. It needs to be addressed given recent trends towards minimally invasive procedures in treating insertional Achilles pathology. This study precisely delineated the footprint in each region of the insertion by creating a trapezoid pattern to compare the coordinates across these areas. This could lead to future three-dimensional reconstruction of the Achilles insertional footprint and patient- specific instrumentation software directed towards optimizing the management of Insertional Achilles pathology.

The Functionality of Membrane-Inserting Proteins and Peptides: Curvature Sensing, Generation, and Pore Formation.

Proteins and peptides with hydrophobic and amphiphilic segments are responsible for many biological functions. The sensing and generation of membrane curvature are the functions of several protein domains or motifs. While some specific membrane proteins play an essential role in controlling the curvature of distinct intracellular membranes, others participate in various cellular processes such as clathrin-mediated endocytosis, where several proteins sort themselves at the neck of the membrane bud. A few membrane-inserting proteins form nanopores that permeate selective ions and water to cross the membrane. In addition, many natural and synthetic small peptides and protein toxins disrupt the membrane by inducing nonspecific pores in the membrane. The pore formation causes cell death through the uncontrolled exchange between interior and exterior cellular contents. In this article, we discuss the insertion depth and orientation of protein/peptide helices, and their role as a sensor and inducer of membrane curvature as well as a pore former in the membrane. We anticipate that this extensive review will assist biophysicists to gain insight into curvature sensing, generation, and pore formation by membrane insertion.

Development and application of a virus-induced gene silencing system for functional genomics in pecan (Carya illinoinensis)

Pecan is a high-value nut tree that cultivated globally. Nowadays, in-depth studies of this species are often hampered by lacking of efficient molecular genetic tools. To facilitate functional genomics in pecan, a virus-induced gene silencing (VIGS) system based on tobacco rattle virus (TRV) was explored in this study. We used pecan magnesium chelatase subunit H (CiChlH) gene as a visual indicator to evaluate the effect of several factors including infiltration method, insert size, insert orientation, inoculation concentration, host genotype, and culture temperature on VIGS. Our results showed that the optimized conditions for pecan VIGS system were as followed: construction of TRV-based vector harboring ∼300 bp target sequence in sense or antisense orientation, adjustment of inoculation solution to a final OD600 of 0.7, use of syringe infiltration method, inoculation of ‘Pawnee’ or ‘Shaoxing’ seedlings at 2∼4 true-leaf stage with obvious shoot apical growth, and subjecting plants to a temperature cycle of 24 °C (day, 12 h)/16 °C (night, 12 h). Using the optimized system, we obtained an expected photobleaching at 4 weeks post infiltration. To further verify the stability of the system, a pecan phenylalanine ammonialyase (CiPAL) gene was used for silencing and we detected a significant reduction in total phenolics in silenced plants with respect to control seedlings, as anticipated. Altogether, the TRV-based VIGS system has been successfully established in pecan and could be used for future reverse genetic studies.

Artificial Water Channels—Progress Innovations and Prospects

Artificial Water Channels—Progress Innovations and Prospects

An Uncut Chip Thickness and Surface Finish Model for Contour Turning with a Corner and Edge Radiused Insert

Uncut chip thickness h and total surface finish profile height Rt is modeled in general contour turning where feed rate is oblique to the workpiece X-axis in the XY plane. The insert surface was parameterized with arc-lengths along corner and edge radius applying a common template. For true insert orientation, projecting the grazing curve GC on the XY plane, h was measured normal to projection at every point. Revolving the GC about X, its subsegment producing surface finish imprint solved and Rt calculated. Contact extremities agreed with published data in cylindrical hard-turning. Brammertz BE and Side-Flow SF effects in surface generated were further modeled. The Rt plateau at low feed rates for BE was smaller for smaller minimum uncut chip thickness (hmin) imposed. A greater side-flow angle (SFA) increased Rt for a fixed feed rate. Tighter bounds to published Rt varying hmin and SFA were rapidly obtained due to use of the common template. Departure from plane strain responsible for SF at cut extremity on the finished surface based on published orthogonal cutting width to h ratios were quantitatively predicted.

Insertion orientation within the cassette affects gene-targeting success during ends-out recombination in the yeast Saccharomyces cerevisiae.

Gene-targeting is one of the most important molecular tools for genomic manipulations for research and industrial purposes. However, many factors influence targeting fidelity undermining the efforts for accurate, fast, and reliable construction of genetically modified yeast strains. Therefore, it is of great academic interest that we uncover as many as possible parameters affecting the recombination mechanisms that enable targeting. Since usually, researchers choose the orientation of the insertion (marker) within the module at random, it seemed interesting to see whether the same module will achieve essentially the same targeting efficiency when the same marker was oriented alternatively concerning the same target gene. Thus, two loci (URA3 and LEU2) and one allele (ura3-52) in a haploid yeast genetic background were targeted by artificial modules bearing homologous insertions in alternative orientations being flanked by long asymmetrical targeting homology to either replace or disrupt a genomic target. Results showed that insertion orientation within the targeting module strongly influences targeting in yeast, regardless of the targeting approach.

A new method of preoperative assessment of correct electrode array alignment based on post-operative measurements in a cochlear implanted cohort

PurposeDuring cochlear implantation surgery, a range of complications may occur such as tip fold-over. We recently developed a method to estimate the insertion orientation of the electrode array. The aim of the study was to determine the optimal angle of orientation in a cohort of cochlear implanted patients.MethodsOn eighty-five CT scans (80 uncomplicated insertions and 5 cases with tip fold-over), location of the electrode array’s Insertion Guide (IG), Orientation marker (OM) and two easily identifiable landmarks (the round window (RW) and the incus short process (ISP)) were manually marked. The angle enclosed by ISP-RW line and the Cochlear™ Slim Modiolar electrode array’s OM line determined the electrode array insertion angle.ResultsThe average insertion angle was 45.0–47.2° ± 10.4–12° SD and was validated with 98% confidence interval. Based on the measurements obtained, patients’ sex and age had no impact on the size of this angle. Although the angles of the tip fold-over cases (44.9°, 46.9°, 34.2°, 54.3°, 55.9°) fell within this average range, the further it diverted from the average it increased the likelihood for tip fold-over.ConclusionElectrode array insertion in the individually calculated angle relative to the visible incus short process provides a useful guide for the surgeon when aiming for the optimal angle, and potentially enhances good surgical outcomes. Our results show that factors other than the orientation angle may additionally contribute to failures in implantation when the Slim Modiolar electrode is used.

Efficacy and initial clinical evaluation of optical genome mapping in the diagnosis of structural variations

To investigate the efficacy and value of optical genome mapping (OGM) in detecting chromosomal structural variations. In a clinical study about high-precision analysis of genomic structural variation for complex genetic diseases, a retrospective study was performed on the cases with karyotyping at the department of Obstetrics and Gynecology, and Endocrinology of Peking Union Medical College Hospital from January to December 2021. Ten cases with abnormal karyotype was detected by OGM. Partial cases were verified by fluorescence in situ hybridization (FISH), SNP array or CNV-seq. Results of ten cases, nine were detected with abnormality by OGM, including unbalanced chromosomal rearrangements (n=3), translocation (n=5) and paracentric inversion (n=1), and the results were in concordance with other standard assays. However, one case with breakpoint and reconnected at centromere has not been detected. In conclusion, ten samples were comprehensively analyzed by karyotyping, FISH, SNP array or CNV-seq, and OGM, and results demonstrated that optical genome mapping as a new technology can not only detect unbalanced rearrangements such as copy number variants as well as balanced translocations and inversions, but more importantly, it can refine breakpoints and orientation of duplicated segments or insertions. So it can contribute to the diagnosis of genetic diseases and prevent birth defect. However, the current technology is not yet capable of detecting breakpoints of balanced structural variations lying within unmapped regions.

Interaction of Cyanine-D112 with Binary Lipid Mixtures: Molecular Dynamics Simulation and Differential Scanning Calorimetry Study.

This comprehensive molecular dynamics (MD) simulation and experimental study investigates the lipid bilayer interactions of dye D112 for potential photodynamic therapy (PDT) applications. PDT involves formation of a reactive oxidant species in the presence of a light sensitive molecule and light, interrupting cellular functions. D112 was developed as a photographic emulsifier, and we hypothesized that its combined cationic and lipophilic nature can render a superior photosensitizing property–crucial in various light therapies. The focus of this study is to elucidate the binding and insertion mechanisms of D112 with mixed lipid bilayers of anionic dipalmitoyl-phosphatidylserine (DPPS) and zwitterionic dipalmitoyl-phosphatidylcholine (DPPC) lipids to resemble cancer cell membranes. Our studies confirm initial electrostatic binding between the positively charged moieties of D112 and negatively charged lipid headgroups. Additionally, MD simulations combined with differential scanning calorimetry (DSC) studies confirm that D112-lipid interactions are governed by enthalpy-driven nonclassical hydrophobic effects in the membrane interior. It was further noted that despite the electrostatic preference of D112 toward the anionic lipids, D112 molecules colocalized on DPPC-rich domains after insertion. Atomistic level MD studies point toward two possible insertion mechanisms for D112: harpoon and flip. Further insights from the simulation showcase the interactions of low and high aggregates of D112 with the bilayer as the concentration of D112 increases in solution. The size of aggregates modulates the orientation and degree of insertion, providing important information for future studies on membrane permeation mechanisms.

Macromolecule sensing and tumor biomarker detection by harnessing terminal size and hydrophobicity of viral DNA packaging motor channels into membranes and flow cells.

Biological nanopores for single-pore sensing have the advantage of size homogeneity, structural reproducibility, and channel amenability. In order to translate this to clinical applications, the functional biological nanopore must be inserted into a stable system for high-throughput analysis. Here we report factors that control the rate of pore insertion into polymer membrane and analyte translocation through the channel of viral DNA packaging motors of Phi29, T3 and T7. The hydrophobicity of aminol or carboxyl terminals and their relation to the analyte translocation were investigated. It was found that both the size and the hydrophobicity of the pore terminus are critical factors for direct membrane insertion. An N-terminus or C-terminus hydrophobic mutation is crucial for governing insertion orientation and subsequent macromolecule translocation due to the one-way traffic property. The N- or C-modification led to two different modes of application. The C-terminal insertion permits translocation of analytes such as peptides to enter the channel through the N terminus, while N-terminus insertion prevents translocation but offers the measurement of gating as a sensing parameter, thus generating a tool for detection of markers. A urokinase-type Plasminogen Activator Receptor (uPAR) binding peptide was fused into the C-terminal of Phi29 nanopore to serve as a probe for uPAR protein detection. The uPAR has proven to be a predictive biomarker in several types of cancer, including breast cancer. With an N-terminal insertion, the binding of the uPAR antigen to individual peptide probe induced discretive steps of current reduction due to the induction of channel gating. The distinctive current signatures enabled us to distinguish uPAR positive and negative tumor cell lines. This finding provides a theoretical basis for a robust biological nanopore sensing system for high-throughput macromolecular sensing and tumor biomarker detection.

Theoretical Study on Ethylene Polymerization Catalyzed by Half-Titanocenes Bearing Different Ancillary Groups

Half-titanocenes are well known to show high activity for ethylene polymerization and good capability for copolymerization of ethylene with other olefins, and the ancillary ligands can crucially affect the catalytic performance. In this paper, the mechanisms of ethylene polymerization catalyzed by three half-metallocenes, (η5-C5Me5)TiCl2(O-2,6-iPr2C6H3) (1), (η5-C5Me5)TiCl2(N=CtBu2) (2) and [Me2Si(η5-C5Me4)(NtBu)]TiCl2 (3), have been investigated by density functional theory (DFT) method. At the initiation stage, a higher free energy barrier was determined for complex 1, probably due to the presence of electronegative O atom in phenoxy ligand. At the propagation stage, front-side insertion of the second ethylene is kinetically more favorable than back-side insertion for complexes 1 and 2, while both side insertion orientations are comparable for complex 3. The energy decomposition showed that the bridged cyclopentadienyl amide ligand could enhance the rigidity of the active species as suggested by the lowest deformation energy derived from 3. At the chain termination stage, β-H transfer was calculated to be a dominant chain termination route over β-H elimination, presumably owing to the thermodynamic perspective.

Fluid–Structure Interaction and Non-Fourier Effects in Coupled Electro-Thermo-Mechanical Models for Cardiac Ablation

In this study, a fully coupled electro-thermo-mechanical model of radiofrequency (RF)-assisted cardiac ablation has been developed, incorporating fluid–structure interaction, thermal relaxation time effects and porous media approach. A non-Fourier based bio-heat transfer model has been used for predicting the temperature distribution and ablation zone during the cardiac ablation. The blood has been modeled as a Newtonian fluid and the velocity fields are obtained utilizing the Navier–Stokes equations. The thermal stresses induced due to the heating of the cardiac tissue have also been accounted. Parametric studies have been conducted to investigate the effect of cardiac tissue porosity, thermal relaxation time effects, electrode insertion depths and orientations on the treatment outcomes of the cardiac ablation. The results are presented in terms of predicted temperature distributions and ablation volumes for different cases of interest utilizing a finite element based COMSOL Multiphysics software. It has been found that electrode insertion depth and orientation has a significant effect on the treatment outcomes of cardiac ablation. Further, porosity of cardiac tissue also plays an important role in the prediction of temperature distribution and ablation volume during RF-assisted cardiac ablation. Moreover, thermal relaxation times only affect the treatment outcomes for shorter treatment times of less than 30 s.

Optical genome mapping enables constitutional chromosomal aberration detection

Chromosomal aberrations including structural variations (SVs) are a major cause of human genetic diseases. Their detection in clinical routine still relies on standard cytogenetics. Drawbacks of these tests are a very low resolution (karyotyping) and the inability to detect balanced SVs or indicate the genomic localization and orientation of duplicated segments or insertions (copy number variant [CNV] microarrays). Here, we investigated the ability of optical genome mapping (OGM) to detect known constitutional chromosomal aberrations. Ultra-high-molecular-weight DNA was isolated from 85 blood or cultured cells and processed via OGM. A de novo genome assembly was performed followed by structural variant and CNV calling and annotation, and results were compared to known aberrations from standard-of-care tests (karyotype, FISH, and/or CNV microarray). In total, we analyzed 99 chromosomal aberrations, including seven aneuploidies, 19 deletions, 20 duplications, 34 translocations, six inversions, two insertions, six isochromosomes, one ring chromosome, and four complex rearrangements. Several of these variants encompass complex regions of the human genome involved in repeat-mediated microdeletion/microduplication syndromes. High-resolution OGM reached 100% concordance compared to standard assays for all aberrations with non-centromeric breakpoints. This proof-of-principle study demonstrates the ability of OGM to detect nearly all types of chromosomal aberrations. We also suggest suited filtering strategies to prioritize clinically relevant aberrations and discuss future improvements. These results highlight the potential for OGM to provide a cost-effective and easy-to-use alternative that would allow comprehensive detection of chromosomal aberrations and structural variants, which could give rise to an era of "next-generation cytogenetics."

Variations in Dimensions and Attachments of the Plantaris Muscle

Plantaris is a rudimentary muscle of the calf that is considered an accessory to the gastrocnemius. It has been harvested for use ranging from grafts in hand surgery (https://www.jhandsurg.org/article/S0363-5023(07)00773-3/abstract) to heart valve repair (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC152834/). It has been postulated as the source of tendinopathy of the Achilles tendon as well as the tendon of the tibialis posterior muscle (https://www.hindawi.com/journals/bmri/2018/9623579/). This study evaluates the plantaris muscle, its tendon, and attachments, in dissected cadavers from the Fall 2020 semester of the gross anatomy course at D'Youville College. Typically, the plantaris is a slim fusiform-shaped muscle that originates from the lateral supracondylar line of the femur and inserts medial to the Achilles tendon on the calcaneal tuberosity. Three variations of the orientation of the tendon insertion were discovered in this study. Equally common were attachment of the plantaris tendon medial to the Achilles tendon and attachment deep to the Achilles tendon. Also seen in a few specimens was attachment of the tendon to the crural fascia. The dimensions of the muscle, length and width of the tendon, and width of the tendon attachment were recorded and analyzed. Knowledge of the variations of the size and differences in location and width of the insertion of the plantaris tendon will aid in surgical procedures, in diagnosis of regional tendinopathy, and may be of importance in possible further research.

Muscle Fibre Architecture of Thoracic and Lumbar Longissimus Dorsi Muscle in the Horse.

Simple SummaryAs the longissimus dorsi muscle is the largest muscle in the equine back, it has great influence on the stability of the spine and facilitates proper locomotion. In general, muscle function is determined by its specific intramuscular architecture. However, only limited three-dimensional metrical data are available for the inner organisation of the equine longissimus dorsi muscle. The thoracic and lumbar longissimus muscles of five formalin-fixed cadaveric horse backs of different ages and body types were dissected layerwise from cranial to caudal. Three-dimensional coordinates along individual muscle fibre bundles were digitised from the origin to the insertion and 3D models were created using imaging software and computed tomography. The muscle was divided into functional compartments and morphometric parameters (muscle fascicle length, pennation angles, muscle volume and the physiological cross-sectional area (PCSA)) were determined. Fascicle length showed the highest values in the thoracic region and decreased from cranial to caudal, while in most caudal compartments, fascicle length was less than 50% of the fascicle length in thoracic compartments. The pennation angles differ between compartments. In the cranial compartment, fascicles almost run parallel to the horizontal plane (mean angle 0°), while in the caudal compartment, the angles increase up to a mean angle of 38°. In the sagittal plane, the pennation angles varied from parallel (0°) in cranial compartments to 0–22° in the caudal compartments. The muscle volume ranged from 1350 cm3 to 4700 cm3 and PCSA from 219 cm2 to 700 cm2. This study lays the anatomical basis for a biomechanical model to simulate muscle function.As the longissimus dorsi muscle is the largest muscle in the equine back, it has great influence on the stability of the spine and facilitates proper locomotion. The longissimus muscle provides support to the saddle and rider and thereby influences performance in the horse. Muscular dysfunction has been associated with back disorders and decline of performance. In general, muscle function is determined by its specific intramuscular architecture. However, only limited three-dimensional metrical data are available for the inner organisation of the equine longissimus dorsi muscle. Therefore, we aimed at investigating the inner architecure of the equine longissimus. The thoracic and lumbar longissimus muscles of five formalin-fixed cadaveric horse backs of different ages and body types were dissected layerwise from cranial to caudal. Three-dimensional coordinates along individual muscle fibre bundles were recorded using a digitisation tool (MicroScribe®), to capture their origin, insertion and general orientation. Together with skeletal data from computed tomography (CT) scans, 3D models were created using imaging software (Amira). For further analysis, the muscle was divided into functional compartments during preparation and morphometric parameters, such as the muscle fascicle length, pennation angles to the sagittal and horizontal planes, muscle volume and the physiological cross-sectional area (PCSA), were determined. Fascicle length showed the highest values in the thoracic region and decreased from cranial to caudal, with the cranial lumbar compartment showing about 75% of cranial fascicle length, while in most caudal compartments, fascicle length was less than 50% of the fascicle length in thoracic compartments. The pennation angles to the horizontal plane show that there are differences between compartments. In most cranial compartments, fascicles almost run parallel to the horizontal plane (mean angle 0°), while in the caudal compartment, the angles increase up to a mean angle of 38°. Pennation angles to the sagittal plane varied not only between compartments but also within compartments. While in the thoracic compartments, the fascicles run nearly parallel to the spine, in the caudal compartments, the mean angles range from 0–22°. The muscle volume ranged from 1350 cm3 to 4700 cm3 depending on body size. The PCSA ranged from 219 cm2 to 700 cm2 depending on the muscle volume and mean fascicle length. In addition to predictable individual differences in size parameters, there are obvious systemic differences within the muscle architecture along the longissimus muscle which may affect its contraction behaviour. The obtained muscle data lay the anatomical basis for a specific biomechanical model of the longissimus muscle, to simulate muscle function under varying conditions and in comparison to other species.

Interaction between Antimicrobial Peptide CM15 and a Model Cell Membrane Affected by CM15 Terminal Amidation and the Membrane Phase State.

Antimicrobial peptides (AMPs) have been proposed as an effective class of antimicrobial agents against microorganisms. In this work, the interaction between an antimicrobial peptide, CM15, and a negatively charged phospholipid bilayer, DPPG, was studied via sum frequency generation (SFG) vibrational spectroscopy. Two structurally correlated characteristic variables were introduced to reveal the interaction mechanism/efficiency, i.e. C-terminal amidation and temperature variation (∼20 °C, room temperature, and ∼35 °C, close to human body temperature). Experimental results indicated that owing to the increased positive charge, C-terminal amidation resulted in rapid adsorption onto the bilayer surface and efficient disruption of the outer layer, exhibiting less ordered insertion orientation. The elevated temperature (from ∼20 °C to ∼35 °C) promoted the penetration of both the outer and inner leaflets by the peptides and finally led to the disruption of the whole bilayer owing to the enhanced fluidity of the bilayer. From the perspective of the interaction mechanism, this experimental study provides two practical cues to understand the disruption process of the negatively charged model biomembranes, which can lay the structural foundation for designing and developing high-efficiency antimicrobial peptides.