Biomechanical implications of lumbar intervertebral disc fenestration in rabbits: Comparison of ex vivo and in vivo conditions as an experimental model for chrondrodystrophic dogs with type 1 intervertebral disc disease.

Objective: To compare the effect of intervertebral disc (IVD) fenestration on L3/4 range of motion (ROM) under ex vivo and in vivo conditions in a rabbit model.

Study Design: Randomized experimental study.

Animals: New Zealand White rabbits (ex vivo: n = 18; in vivo: n = 12).

Pd(μ-L)Pt Pd(μ-L)RuCl: chlorido ancillary ligands as defining factors in the host-guest interactions of M(μ-L)M' heterodimetallic supramolecular architectures.

In supramolecular architectures, the interactions between host and guest molecules are governed by non-covalent forces such as hydrogen (H) bonding, hydrophobic and electrostatic interactions. We alter here the cavity microenvironment to control the interactions between guest and host molecules and study the effects of introducing axial chlorido ligands through the use of an octahedral building block in M(μ-L)M' architectures. We prepared the heterodimetallic Pd(μ-L)Pt C and Pd(μ-L)RuClC architectures and demonstrated the role of 'classic' non-covalent forces in their host-guest chemistry with anionic and neutral molecules, while the cages also underwent disassembly and reassembly upon addition of external stimuli.

Single-Step Synthesis of a Heterometallic [CuPdL] Hybrid Metal-Organic Coordination Cage.

Traditional methods of assembling low-symmetry heterometallic cage architectures are limited to stepwise construction and combinations of inert and labile metal ions, affording complex, anisotropic cage structures by sacrificing synthetic ease. Herein, a heterometallic [CuPdL] lantern-type cage has been assembled in a single self-assembly step through the use of a heteroditopic ligand with two different metal-binding groups. The resultant cage complex is a fusion of two common lantern-type cage motifs-carboxylate-based metal-organic CuL cages and pyridyl-based PdL coordination cages.

Caudal median sternotomy and diaphragmotomy in addition to midline celiotomy for liver lobectomy: Description of surgical technique and clinical outcome in 22 dogs.

Background: During liver lobectomy, exposure of the liver hilus may be improved with the addition of a caudal median sternotomy and diaphragmotomy. This study aimed to report the surgical technique for this procedure and its clinical outcomes when performed in dogs.

Methods: The clinical records of dogs undergoing a caudal median sternotomy for liver lobectomy between 2010 and 2023 were retrospectively reviewed.

Modulating the guest binding ability within mixed-coordination geometry [Pd(μ-L)RuCl] and [Pd(μ-L)Pt] cage architectures.

Heterobimetallic cages built from Pd and either octahedral Ru or square-planar Pt moieties and bridged by ligands with H bonding-accepting or -donating properties are reported. They showed stimulus-responsive dis- and reassembly, while guest binding was found to be dependent on the complementary properties of the guest to the host in terms of charge, size and H bonding properties.

Towards building blocks for metallosupramolecular structures: non-symmetrically-functionalised ferrocenyl compounds.

Metallosupramolecular architectures formed from metal ions and bridging ligands are increasing in popularity due to their range of applications and ease of self-assembly. Many are able to readily change their shape and/or function in response to an external stimulus and have the ability to encapsulate guest molecules within their internal cavities. Ferrocenyl groups (Fc) have been incorporated previously within the bridging ligands of metallosupramolecular structures due to their ideal attributes brought about by the structural and rotational flexiblity of the two cyclopentadienyl (Cp) rings coordinated to the Fe(II) centre.

Interaction of dinuclear Co(III) cylinders with higher-order DNA structures.

Alternative DNA structures play critical roles in fundamental biological processes linked to human diseases. Thus, targeting and stabilizing these structures by specific ligands could affect the progression of cancer and other diseases. Here, we describe, using methods of molecular biophysics, the interactions of two oxidatively locked [CoL] cylinders, rac-2 and meso-1, with diverse alternative DNA structures, such as junctions, G quadruplexes, and bulges.

Photochemistry of Ru(II) Triazole Complexes with 6-Membered Chelate Ligands: Detection and Reactivity of Ligand-Loss Intermediates.

Photochemical ligand release from metal complexes may be exploited in the development of novel photoactivated chemotherapy agents for the treatment of cancer and other diseases. Highly intriguing photochemical behavior is reported for two ruthenium(II) complexes bearing conformationally flexible 1,2,3-triazole-based ligands incorporating a methylene spacer to form 6-membered chelate rings. [Ru(bpy)(pictz)] () and [Ru(bpy)(btzm)] () (bpy = 2,2'-bipyridyl; pictz = 1-(picolyl)-4-phenyl-1,2,3-triazole; btzm = bis(4-phenyl-1,2,3-triazol-4-yl)methane) exhibit coordination by the triazole ring through the less basic N2 atom as a consequence of chelation and readily undergo photochemical release of the pictz and btzm ligands (ϕ = 0.

A dynamic covalent approach to [PtL] cages.

A dynamic covalent approach was exploited to generate a family of homometallic [PtL] cage (predominantly [PtL] systems) architectures. The family of platinum(II) architectures were characterized using H nuclear magnetic resonance (NMR) and diffusion ordered spectroscopy (DOSY), electrospray ionization mass spectrometry (ESI-MS) and the molecular structures of two cages were determined by X-ray crystallography.

Anterior cruciate ligament zoobiquity: Can man's best friend tell us we are being too cautious with the implementation of osteotomy to correct posterior tibial slope.

Anterior cruciate ligament (ACL) reconstruction (ACLR) is used to treat clinical instability post ACL rupture, however, there is a high rate of incomplete return to sport and rerupture. There is increasing interest in posterior tibial slope as an intrinsic risk factor for ACLR failure and persistent instability. Zoobiquity describes the collaboration between the human and veterinary professions in order to advance the scientific understanding of both fields.

Pedicle screw pull-out testing in polyurethane foam blocks: Effect of block orientation and density.

Synthetic bone models such as polyurethane (PU) foam are a well-established substitute to cadaveric bone for screw pull-out testing; however, little attention has been given to the effect of PU foam anisotropy on orthopaedic implant testing. Compressive and screw pull-out performance in three PU foam densities; 0.16 g/cm (PCF 10), 0.

Controlling Excited State Localization in Bichromophoric Photosensitizers via the Bridging Group.

A series of photosensitizers comprised of both an inorganic and an organic chromophore are investigated in a joint synthetic, spectroscopic, and theoretical study. This bichromophoric design strategy provides a means by which to significantly increase the excited state lifetime by isolating the excited state away from the metal center following intersystem crossing. A variable bridging group is incorporated between the donor and acceptor units of the organic chromophore, and its influence on the excited state properties is explored.

Lateral fenestration of lumbar intervertebral discs in rabbits: development and characterisation of an in vivo preclinical model with multi-modal endpoint analysis.

Purpose: To evaluate the biological and biomechanical effects of fenestration/microdiscectomy in an in vivo rabbit model, and in doing so, create a preclinical animal model of IVDD.

Methods: Lateral lumbar IVD fenestration was performed in vivo as single- (L3/4; n = 12) and multi-level (L2/3, L3/4, L4/5; n = 12) fenestration in skeletally mature 6-month-old New Zealand White rabbits. Radiographic, micro-CT, micro-MRI, non-destructive robotic range of motion, and histological evaluations were performed 6- and 12-weeks postoperatively.

Heterometallic cages: synthesis and applications.

High symmetry metallosupramolecular architectures (MSAs) have been exploited for a range of applications including molecular recognition, catalysis and drug delivery. Recently there have been increasing efforts to enhance those applications by generating reduced symmetry MSAs. While there are several emerging methods for generating lower symmetry MSAs, this tutorial review examines the general methods used for synthesizing heterometallic MSAs with a particular focus on heterometallic cages.

Comparison of three methods for nucleus pulposus volume measurement in rabbit lumbar spines: a preclinical model for measurement of the effectiveness of prophylactic intervertebral disk fenestration in dogs.

Objective: Compare 3 methods of nucleus pulposus (NP) volume measurement using the rabbit lumbar spines as a preclinical model to determine the effectiveness of prophylactic intervertebral disk fenestration in dogs.

Animals: Twelve 9-month-old, skeletally mature female entire New Zealand White rabbits weighing between 3.5 to 4.

Exploiting reduced-symmetry ligands with pyridyl and imidazole donors to construct a second-generation stimuli-responsive heterobimetallic [PdPtL] cage.

A new sequential metalation strategy that enables the assembly of a new more robust reduced symmetry heterobimetallic [PdPtL] cage C is reported. By exploiting a low-symmetry ditopic ligand (L) that features imidazole and pyridine donor units we were able to selectively form a [Pt(L)] "open-cage" complex. When this was treated with Pd(ii) ions the cage C assembled.

Preclinical in vivo animal models of intervertebral disc degeneration. Part 1: A systematic review.

Intervertebral disc degeneration (IVDD), a widely recognized cause of lower back pain, is the leading cause of disability worldwide. A myriad of preclinical in vivo animal models of IVDD have been described in the literature. There is a need for critical evaluation of these models to better inform researchers and clinicians to optimize study design and ultimately, enhance experimental outcomes.

Ferrocene-Derived Palladium(II)-Based Metallosupramolecular Structures: Synthesis, Guest Interaction, and Stimulus-Responsiveness Studies.

Using ferrocene-based ligand systems, a series of heterobimetallic architectures of the general formula [PdL] were designed with the aim of installing an opening and closing mechanism that would allow the release and binding of guest molecules. Palladium complex formation was achieved through coordination to pyridyl groups, and using 2-, 3-, and 4-pyridyl derivatives provided access to defined PdL, PdL, and PdL structures, respectively. The supramolecular complexes were characterized using nuclear magnetic resonance (NMR) and infrared spectroscopy, mass spectrometry, and elemental analysis, and for some examples density functional theory calculations and single-crystal X-ray diffraction analysis.

The Effect of Location of a Unicortical Defect on the Mechanical Properties of Rabbit Tibiae: A Model of the Distal Jig Pin Hole in Tibial Plateau Levelling Osteotomy.

Objective:  The aim of this study was to determine the effect of a unicortical defect at either the mid-diaphysis (MD) or distal metaphysis (DM) on the torsional properties of tibiae in an rabbit model, and to further examine optimal distal jig pin position for the canine tibial plateau levelling osteotomy (TPLO) procedure.

Study Design:  Thirty-eight tibiae from 19 skeletally mature female New Zealand White rabbits were assigned to one of three groups; Group 1: intact, Group 2: MD defect and Group 3: DM defect. Defects were created using a 1.

The Biologically Inspired Abilities of Metallosupramolecular Architectures.

Natural machinery such as proteins and enzymes can bind substrates and perform intricate functions on these molecules. This behaviour is mediated by highly ordered but conformationally flexible structures dictated through favourable intra- and intermolecular interactions. Metallosupramolecular architectures (MSAs) function as synthetic machinery that are responsive to their environment, and display similar, but less impressive, abilities to their biological counterparts.

Vacuum-Sealed Hot Water Bath Immersion for the Preparation of Anatomical and Surgical Cadaveric Bone Models.

Bone models serve many purposes, including improving anatomical understanding, preoperative surgical planning, and intraoperative referencing. Several techniques for the maceration of soft tissues have been described, mainly for forensic analysis. For clinical research and medical use, these methods have been superseded by three-dimensional (3D) printed models, which require substantial equipment and expertise, and are costly.

Hydrazone- and imine-containing [PdPtL] cages: a comparative study of the stability and host-guest chemistry.

A new [PdPtL] heterobimetallic cage containing hydrazone linkages has been synthesised using the sub-component self-assembly approach. H and DOSY nuclear magnetic resonance (NMR) spectroscopy and electrospray ionisation mass spectrometry (ESIMS) data were consistent with the formation of the [PdPtL] architecture. The cage was stimulus-responsive and could be partially disassembled and reassembled by the addition of dimethylaminopyridine (DMAP) and -tolenesulfonic acid (TsOH), respectively.

Exploiting Supramolecular Interactions to Control Isomer Distributions in Reduced-Symmetry [PdL] Cages.

High-symmetry metallosupramolecular architectures (MSAs) have been exploited for a range of applications including molecular recognition, catalysis, and drug delivery. Recently, there have been increasing efforts to enhance those applications by generating reduced-symmetry MSAs. Here we report our attempts to use supramolecular (dispersion and hydrogen-bonding) forces and solvophobic effects to generate isomerically pure [Pd(L)] cage architectures from a family of new reduced-symmetry ditopic tripyridyl ligands.

Heterotrimetallic Double Cavity Cages: Syntheses and Selective Guest Binding.

A strategy for the generation of heterotrimetallic double cavity (DC) cages [Pd Pt L ] (DC1: n=1, m=2; and DC2: n=2, m=1) is reported. The DC cages were generated by combining an inert platinum(II) tetrapyridylaldehyde complex with a suitably substituted pyridylamine and Pd ions. H and DOSY nuclear magnetic resonance spectroscopy (NMR) and electrospray ionization mass spectrometry (ESIMS) data were consistent with the formation of the DC architectures.

Synthetic Strategy Towards Heterodimetallic Half-Sandwich Complexes Based on a Symmetric Ditopic Ligand.

Multimetallic complexes have been shown in several examples to possess greater anticancer activity than their monometallic counterparts. The increased activity has been attributed to altered modes of action. We herein report the synthesis of a series of heterodimetallic compounds based on a ditopic ligand featuring 2-pyridylimine chelating motifs and organometallic half-sandwich moieties.