Cortical thickness adaptation to combined mechanical loading and parathyroid hormone treatments is site specific and synergistic in the mouse tibia model.

In this study, we aimed to quantify the localised effects of mechanical loading (ML), low (20 μg/kg/day), moderate (40 μg/kg/day) or high (80 μg/kg/day) dosages of parathyroid hormone (PTH), and combined (PTHML) treatments on cortical bone adaptation in healthy 19-week old female C57BL/6 mice. To this end, we utilise a previously reported image analysis algorithm on μCT data of the mouse tibia published by Sugiyama et al. (2008) to measure changes in cortical area, marrow cavity area and local cortical thickness measures (ΔCt.

Anatomical considerations for the surgical approach to the canine accessory lung lobe.

Objective: To describe (1) the surgical anatomy of the accessory lung lobe (ALL) including vasculature and pulmonary ligamentous attachments and (2) lobectomy through a right thoracotomy and median sternotomy.

Study Design: Cadaveric anatomical study.

Animals: Nine adult canine cadavers, free of disease affecting the thoracic cavity and lung parenchyma.

The effect of flushing of the common bile duct on hepatobiliary markers and short-term outcomes in dogs undergoing cholecystectomy for the management of gall bladder mucocele: A randomized controlled prospective study.

Objective: To determine the effect of flushing of the common bile duct (CBD) on hepatobiliary markers and short-term outcome in dogs undergoing cholecystectomy for the management of gallbladder mucocele (GBM).

Study Design: Randomized, controlled, prospective study.

Animals: Thirty-two client-owned dogs.

Clinical use and complications of percutaneous cystostomy pigtail catheters in 25 cats.

Objectives: The aims of this study were to describe the indications for percutaneous pigtail catheter placement in cats requiring urine diversion, and to report the associated intra- and postoperative complications.

Methods: The medical records of cats that underwent percutaneous pigtail catheter placement for urine diversion between January 2011 and May 2021 were retrospectively reviewed.

Results: Twenty-five cats were included.

Rostral mandibulectomy for the management of trismus in a cat.

Case Summary: A 5-year-old domestic shorthair cat was evaluated for weight loss and poor coat condition due to an inability to open its mouth (trismus) following head trauma 2 months previously. Contrast CT, electromyography and temporal muscle biopsy identified findings consistent with muscle atrophy, denervation and degeneration. Conservative treatment failed to improve the trismus so a rostral mandibulectomy was performed.

Mechanical strain-mediated reduction in RANKL expression is associated with RUNX2 and BRD2.

Mechanical loading-related strains trigger bone formation by osteoblasts while suppressing resorption by osteoclasts, uncoupling the processes of formation and resorption. Osteocytes may orchestrate this process in part by secreting sclerostin (SOST), which inhibits osteoblasts, and expressing receptor activator of nuclear factor-κB ligand (RANKL/TNFSF11) which recruits osteoclasts. Both SOST and RANKL are targets of the master osteoblastic transcription factor RUNX2.

Long-term outcome of female dogs treated for intramural ectopic ureters with cystoscopic-guided laser ablation.

Objective: To report the complications and long-term outcome of female dogs with intramural ectopic ureter(s) (iEU) undergoing cystoscopic-guided laser ablation (CLA) and determine the effect of post-CLA neutering on urinary continence.

Study Design: Retrospective clinical study.

Animals Or Sample Population: Thirty-four client-owned dogs.

Cortical Thickness Adaptive Response to Mechanical Loading Depends on Periosteal Position and Varies Linearly With Loading Magnitude.

The aim of the current study was to quantify the local effect of mechanical loading on cortical bone formation response at the periosteal surface using previously obtained μCT data from a mouse tibia mechanical loading study. A novel image analysis algorithm was developed to quantify local cortical thickness changes (ΔCt.Th) along the periosteal surface due to different peak loads (0N ≤ F ≤ 12N) applied to right-neurectomised mature female C57BL/6 mice.

Influence of muscle-sparing lateral thoracotomy on postoperative pain and lameness: A randomized clinical trial.

Objective: To assess and compare the magnitude of lameness and level of pain after muscle-sparing lateral thoracotomy (MSLT) and standard lateral thoracotomy (SLT) in dogs.

Study Design: Randomized, blinded, prospective clinical study.

Animals: Twenty-eight client-owned dogs.

Mechanical strain-mediated reduction in RANKL expression is associated with RUNX2 and BRD2.

Mechanical loading-related strains trigger bone formation by osteoblasts while suppressing resorption by osteoclasts, uncoupling the processes of formation and resorption. Osteocytes may orchestrate this process in part by secreting sclerostin (SOST), which inhibits osteoblasts, and expressing receptor activator of nuclear factor-κB ligand (RANKL/TNFSF11) which recruits osteoclasts. Both SOST and RANKL are targets of the master osteoblastic transcription factor RUNX2.

Bone gain following loading is site-specifically enhanced by prior and concurrent disuse in aged male mice.

The primary aim of osteoanabolic therapies is to strategically increase bone mass in skeletal regions likely to experience high strains. In the young healthy skeleton, this is primarily achieved by bone's adaptation to loading. This adaptation appears to fail with age, resulting in osteoporosis and fractures.

Murine Axial Compression Tibial Loading Model to Study Bone Mechanobiology: Implementing the Model and Reporting Results.

In vivo, tibial loading in mice is increasingly used to study bone adaptation and mechanotransduction. To achieve standardized and defined experimental conditions, loading parameters and animal-related factors must be considered when performing in vivo loading studies. In this review, we discuss these loading and animal-related experimental conditions, present methods to assess bone adaptation, and suggest reporting guidelines.

Outcomes of dogs treated for extrahepatic congenital portosystemic shunts with thin film banding or ameroid ring constrictor.

Objective: To compare the outcomes of dogs treated at a single institution for single extrahepatic congenital portosystemic shunts (CPSS) by thin film banding (TFB) or by placement of an ameroid constrictor (AC).

Study Design: Retrospective case series.

Animals: Seventy-six client-owned dogs with CPSS treated with TFB (n = 53) or AC (n = 23).

Mechanical properties of 6 finger-trap suture techniques.

Objective: To identify the most common methods used by surgeons to place finger-trap sutures (FTS), and determine their influence on the biomechanical properties of constructs.

Study Design: Questionnaire and experimental study.

Methods: Six commonly used FTS methods (A-F) were identified from literature review and questionnaire.

Electrosurgery reduces blood loss and immediate postoperative inflammation compared to cold instruments for midline celiotomy in dogs: A randomized controlled trial.

Objectives: To compare the use of an electrosurgical device with traditional cold instruments (scalpel and scissors) for midline celiotomy incision.

Study Design: Prospective randomized controlled clinical trial.

Sample Population: One hundred and twenty client-owned dogs undergoing abdominal surgery.

Parathyroid hormone's enhancement of bones' osteogenic response to loading is affected by ageing in a dose- and time-dependent manner.

Decreased effectiveness of bones' adaptive response to mechanical loading contributes to age-related bone loss. In young mice, intermittent administration of parathyroid hormone (iPTH) at 20-80μg/kg/day interacts synergistically with artificially applied loading to increase bone mass. Here we report investigations on the effect of different doses and duration of iPTH treatment on mice whose osteogenic response to artificial loading is impaired by age.

Old age and the associated impairment of bones' adaptation to loading are associated with transcriptomic changes in cellular metabolism, cell-matrix interactions and the cell cycle.

In old animals, bone's ability to adapt its mass and architecture to functional load-bearing requirements is diminished, resulting in bone loss characteristic of osteoporosis. Here we investigate transcriptomic changes associated with this impaired adaptive response. Young adult (19-week-old) and aged (19-month-old) female mice were subjected to unilateral axial tibial loading and their cortical shells harvested for microarray analysis between 1h and 24h following loading (36 mice per age group, 6 mice per loading group at 6 time points).

Colored Indicator Undergloves Increase the Detection of Glove Perforations by Surgeons During Small Animal Orthopedic Surgery: A Randomized Controlled Trial.

Objective: To determine whether use of colored indicator gloves affects perforation detection rate and to identify risk factors for glove perforation during veterinary orthopedic surgery.

Study Design: Prospective randomized controlled trial.

Sample Population: 574 double pairs of gloves worn during 300 orthopedic surgical procedures (2,296 gloves).

Wnt16 Is Associated with Age-Related Bone Loss and Estrogen Withdrawal in Murine Bone.

Genome Wide Association Studies suggest that Wnt16 is an important contributor to the mechanisms controlling bone mineral density, cortical thickness, bone strength and ultimately fracture risk. Wnt16 acts on osteoblasts and osteoclasts and, in cortical bone, is predominantly derived from osteoblasts. This led us to hypothesize that low bone mass would be associated with low levels of Wnt16 expression and that Wnt16 expression would be increased by anabolic factors, including mechanical loading.

Exercise does not enhance aged bone's impaired response to artificial loading in C57Bl/6 mice.

Bones adapt their structure to their loading environment and so ensure that they become, and are maintained, sufficiently strong to withstand the loads to which they are habituated. The effectiveness of this process declines with age and bones become fragile fracturing with less force. This effect in humans also occurs in mice which experience age-related bone loss and reduced adaptation to loading.

Quantification of Alterations in Cortical Bone Geometry Using Site Specificity Software in Mouse models of Aging and the Responses to Ovariectomy and Altered Loading.

Investigations into the effect of (re)modeling stimuli on cortical bone in rodents normally rely on analysis of changes in bone mass and architecture at a narrow cross-sectional site. However, it is well established that the effects of axial loading produce site-specific changes throughout bones' structure. Non-mechanical influences (e.

Deletion of P58(IPK), the Cellular Inhibitor of the Protein Kinases PKR and PERK, Causes Bone Changes and Joint Degeneration in Mice.

Objective: Protein kinase-like endoplasmic reticulum kinase (PERK) and protein kinase R (PKR) are implicated in endoplasmic reticulum stress-induced arthritis and pro-inflammatory cytokine-mediated cartilage degradation in vitro, respectively. We determined whether knockout of the cellular inhibitor of PERK and PKR, P58(IPK) causes joint degeneration in vivo and whether these molecules are activated in human osteoarthritis (OA).

Materials And Methods: Sections of knee joints from P58(IPK)-null and wild-type mice aged 12-13 and 23-25 months were stained with toluidine blue and scored for degeneration using the osteoarthritis research society international (OARSI) system.

The Contribution of Experimental in vivo Models to Understanding the Mechanisms of Adaptation to Mechanical Loading in Bone.

Changing loading regimens by natural means such as exercise, with or without interference such as osteotomy, has provided useful information on the structure:function relationship in bone tissue. However, the greatest precision in defining those aspects of the overall strain environment that influence modeling and remodeling behavior has been achieved by relating quantified changes in bone architecture to quantified changes in bones' strain environment produced by direct, controlled artificial bone loading. Jiri Hert introduced the technique of artificial loading of bones in vivo with external devices in the 1960s using an electromechanical device to load rabbit tibiae through transfixing stainless steel pins.

Planar cell polarity aligns osteoblast division in response to substrate strain.

Exposure of bone to dynamic strain increases the rate of division of osteoblasts and also influences the directional organization of the cellular and molecular structure of the bone tissue that they produce. Here, we report that brief exposure to dynamic substrate strain (sufficient to rapidly stimulate cell division) influences the orientation of osteoblastic cell division. The initial proliferative response to strain involves canonical Wnt signaling and can be blocked by sclerostin.