Publications by authors named "Herman A W Hazewinkel"

38 Publications

Radiographic, computed tomographic, and arthroscopic findings in labrador retrievers with medial coronoid disease.

Vet Surg 2015 May 16;44(4):511-20. Epub 2014 Oct 16.

Division of Diagnostic Imaging, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.

Objective: To describe the radiographic, computed tomographic (CT), and arthroscopic findings in different age groups of Labrador Retrievers diagnosed with medial coronoid disease (MCD), and to compare the ulnar subtrochlear sclerosis (STS) observed on radiographs with the ratio between the mean attenuation of the ulnar subtrochlear bone and the mean attenuation of the cortical bone measured on CT.

Study Design: Prospective clinical study.

Animals: Dogs (n = 31; 31 elbow joints) and 6 healthy Labrador Retrievers (6 elbow joints).

Methods: Radiographic, CT, and intraoperative arthroscopic images (2008-2012) were evaluated. Statistical analysis was performed for the descriptive study to evaluate the difference in findings between age groups and to investigate the correlation between radiographic and CT evaluated ulnar STS.

Results: Ulnar STS (87.6%) was the most common radiographic findings in dogs ≤12 months and blurring of the cranial edge of the medial coronoid process (MCP; 66.7%) was the most common radiographic findings in dogs >12 months. MCP fragmentation was the most common CT finding in both age groups (93.8% [≤12 months]; 66.7% [>12 months]). A displaced fragment (68.8%) was the most common arthroscopic finding in dogs ≤12 months whereas osteochondromalacia (53.3%) was the most common finding in dogs >12 months. Sensitivity of radiography in detecting MCD was 93.8% (≤12 months) and 73.3% (>12 months) and for CT was 93.8% (≤12 months) and 66.7% (>12 months). Radiographic evaluated ulnar STS was strongly correlated with CT evaluated ulnar STS.

Conclusion: Wide ranges of radiographic, CT, and arthroscopic findings in Labrador Retrievers diagnosed with medial coronoid disease were identified.
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http://dx.doi.org/10.1111/j.1532-950X.2014.12291.xDOI Listing
May 2015

Evidence of cartilage repair by joint distraction in a canine model of osteoarthritis.

Arthritis Rheumatol 2015 Feb;67(2):465-74

University Medical Center Utrecht, Utrecht, The Netherlands.

Objective: Knee osteoarthritis (OA) is a degenerative joint disorder characterized by cartilage, bone, and synovial tissue changes that lead to pain and functional impairment. Joint distraction is a treatment that provides long-term improvement in pain and function accompanied by cartilage repair, as evaluated indirectly by imaging studies and measurement of biochemical markers. The purpose of this study was to evaluate cartilage tissue repair directly by histologic and biochemical assessments after joint distraction treatment.

Methods: In 27 dogs, OA was induced in the right knee joint (groove model; surgical damage to the femoral cartilage). After 10 weeks of OA development, the animals were randomized to 1 of 3 groups. Two groups were fitted with an external fixator, which they wore for a subsequent 10 weeks (one group with and one without joint distraction), and the third group had no external fixation (OA control group). Pain/function was studied by force plate analysis. Cartilage integrity and chondrocyte activity of the surgically untouched tibial plateaus were analyzed 25 weeks after removal of the fixator.

Results: Changes in force plate analysis values between the different treatment groups were not conclusive. Features of OA were present in the OA control group, in contrast to the generally less severe damage after joint distraction. Those treated with joint distraction had lower macroscopic and histologic damage scores, higher proteoglycan content, better retention of newly formed proteoglycans, and less collagen damage. In the fixator group without distraction, similarly diminished joint damage was found, although it was less pronounced.

Conclusion: Joint distraction as a treatment of experimentally induced OA results in cartilage repair activity, which corroborates the structural observations of cartilage repair indicated by surrogate markers in humans.
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http://dx.doi.org/10.1002/art.38906DOI Listing
February 2015

Naturally occurring spinal hyperostosis in dogs as a model for human spinal disorders.

ILAR J 2014 ;55(1):150-63

Both spondylosis and diffuse idiopathic skeletal hyperostosis (DISH) are prevalent in humans and are considered distinct entities. Nowadays, the term spondylosis is in the biomedical literature mostly used when concurrently degenerative disc disease is present. In companion animals, many reports on spondylosis, often without intervertebral disc degeneration, are described. The nomenclature and the definitions of both spondylosis and DISH in biomedical and veterinary literature should be more in line to facilitate comparison. Spondylosis and DISH occur in dogs spontaneously and can co-occur in one animal. Specifically, Boxers may serve as translational disease models for the elucidation of the gene(s) involved in the (etio)pathogenesis of spondylosis and DISH or serve as a test population for newly developed treatment options.
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http://dx.doi.org/10.1093/ilar/ilu012DOI Listing
February 2015

Genome-wide survey indicates involvement of loci on canine chromosomes 7 and 31 in patellar luxation in Flat-Coated Retrievers.

BMC Genet 2014 May 28;15:64. Epub 2014 May 28.

Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.

Background: Patellar luxation is an orthopedic disorder in which the patella moves out of its normal location within the femoral trochlea of the knee and it can lead to osteoarthritis, lameness, and pain. In dogs it is a heritable trait, with both environmental and genetic factors contributing to the phenotype. The prevalence of patellar luxation in the Dutch Flat-Coated Retriever population is 24%. In this study, we investigated the molecular genetics of the disorder in this population.

Results: Genome-wide association analysis of 15,823 single nucleotide polymorphisms (SNPs) in 45 cases and 40 controls revealed that patellar luxation was significantly associated with a region on chromosome CFA07, and possibly with regions on CFA03, CFA31, and CFA36. The exons of the genes in these regions, 0.5 Mb combined, were analyzed further. These exons from 15 cases and a pooled sample from 15 controls were enriched using custom genomic hybridization arrays and analyzed by massive parallel DNA sequencing. In total 7257 variations were detected. Subsequently, a selection of 144 of these SNPs were genotyped in 95 Flat-Coated Retrievers. Nine SNPs, in eight genes on CFA07 and CFA31, were associated with patellar luxation (P <10-4). Genotyping of these SNPs in samples from a variety of breeds revealed that the disease-associated allele of one synonymous SNP in a pseudogene of FMO6 was unique to Flat-Coated Retrievers.

Conclusion: Genome-wide association analysis followed by targeted DNA sequencing identified loci on chromosomes 7 and 31 as being involved in patellar luxation in the Flat-Coated Retriever breed.
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http://dx.doi.org/10.1186/1471-2156-15-64DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4046030PMC
May 2014

Genome wide analysis indicates genes for basement membrane and cartilage matrix proteins as candidates for hip dysplasia in Labrador Retrievers.

PLoS One 2014 30;9(1):e87735. Epub 2014 Jan 30.

Department of Clinical Sciences of Companion Animal, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.

Hip dysplasia, an abnormal laxity of the hip joint, is seen in humans as well as dogs and is one of the most common skeletal disorders in dogs. Canine hip dysplasia is considered multifactorial and polygenic, and a variety of chromosomal regions have been associated with the disorder. We performed a genome-wide association study in Dutch Labrador Retrievers, comparing data of nearly 18,000 single nucleotide polymorphisms (SNPs) in 48 cases and 30 controls using two different statistical methods. An individual SNP analysis based on comparison of allele frequencies with a χ(2) statistic was used, as well as a simultaneous SNP analysis based on Bayesian variable selection. Significant association with canine hip dysplasia was observed on chromosome 8, as well as suggestive association on chromosomes 1, 5, 15, 20, 25 and 32. Next-generation DNA sequencing of the exons of genes of seven regions identified multiple associated alleles on chromosome 1, 5, 8, 20, 25 and 32 (p<0.001). Candidate genes located in the associated regions on chromosomes 1, 8 and 25 included LAMA2, LRR1 and COL6A3, respectively. The associated region on CFA20 contained candidate genes GDF15, COMP and CILP2. In conclusion, our study identified candidate genes that might affect susceptibility to canine hip dysplasia. These genes are involved in hypertrophic differentiation of chondrocytes and extracellular matrix integrity of basement membrane and cartilage. The functions of the genes are in agreement with the notion that disruptions in endochondral bone formation in combination with soft tissue defects are involved in the etiology of hip dysplasia.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0087735PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3907504PMC
September 2014

Gene expression profiling of early intervertebral disc degeneration reveals a down-regulation of canonical Wnt signaling and caveolin-1 expression: implications for development of regenerative strategies.

Arthritis Res Ther 2013 Jan 29;15(1):R23. Epub 2013 Jan 29.

Introduction: Early degeneration of the intervertebral disc (IVD) involves a change in cellular differentiation from notochordal cells (NCs) in the nucleus pulposus (NP) to chondrocyte-like cells (CLCs). The purpose of this study was to investigate the gene expression profiles involved in this process using NP tissue from non-chondrodystrophic and chondrodystrophic dogs, a species with naturally occurring IVD degeneration.

Methods: Dual channel DNA microarrays were used to compare 1) healthy NP tissue containing only NCs (NC-rich), 2) NP tissue with a mixed population of NCs and CLCs (Mixed), and 3) NP tissue containing solely CLCs (CLC-rich) in both non-chondrodystrophic and chondrodystrophic dogs. Based on previous reports and the findings of the microarray analyses, canonical Wnt signaling was further evaluated using qPCR of relevant Wnt target genes. We hypothesized that caveolin-1, a regulator of Wnt signaling that showed significant changes in gene expression in the microarray analyses, played a significant role in early IVD degeneration. Caveolin-1 expression was investigated in IVD tissue sections and in cultured NCs. To investigate the significance of Caveolin-1 in IVD health and degeneration, the NP of 3-month-old Caveolin-1 knock-out mice was histopathologically evaluated and compared with the NP of wild-type mice of the same age.

Results: Early IVD degeneration involved significant changes in numerous pathways, including Wnt/β-catenin signaling. With regard to Wnt/β-catenin signaling, axin2 gene expression was significantly higher in chondrodystrophic dogs compared with non-chondrodystrophic dogs. IVD degeneration involved significant down-regulation of axin2 gene expression. IVD degeneration involved significant down-regulation in Caveolin-1 gene and protein expression. NCs showed abundant caveolin-1 expression in vivo and in vitro, whereas CLCs did not. The NP of wild-type mice was rich in viable NCs, whereas the NP of Caveolin-1 knock-out mice contained chondroid-like matrix with mainly apoptotic, small, rounded cells.

Conclusions: Early IVD degeneration involves down-regulation of canonical Wnt signaling and Caveolin-1 expression, which appears to be essential to the physiology and preservation of NCs. Therefore, Caveolin-1 may be regarded an exciting target for developing strategies for IVD regeneration.
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http://dx.doi.org/10.1186/ar4157DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3672710PMC
January 2013

Intervertebral disc degeneration in the dog. Part 1: Anatomy and physiology of the intervertebral disc and characteristics of intervertebral disc degeneration.

Vet J 2013 Mar 21;195(3):282-91. Epub 2012 Nov 21.

Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 108, 3508 TD Utrecht, The Netherlands.

Intervertebral disc (IVD) degeneration is common in dogs and can give rise to a number of diseases, such as IVD herniation, cervical spondylomyelopathy, and degenerative lumbosacral stenosis. Although there have been many reports and reviews on the clinical aspects of canine IVD disease, few reports have discussed and reviewed the process of IVD degeneration. In this first part of a two-part review, the anatomy, physiology, histopathology, and biochemical and biomechanical characteristics of the healthy and degenerated IVD are described. In Part 2, the aspects of IVD degeneration in chondrodystrophic and non-chondrodystrophic dog breeds are discussed in depth.
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http://dx.doi.org/10.1016/j.tvjl.2012.10.024DOI Listing
March 2013

Intervertebral disc degeneration in the dog. Part 2: chondrodystrophic and non-chondrodystrophic breeds.

Vet J 2013 Mar 12;195(3):292-9. Epub 2012 Nov 12.

Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 108, 3508 TD Utrecht, The Netherlands.

Dogs can be grouped into two distinct types of breed based on the predisposition to chondrodystrophy, namely, non-chondrodystrophic (NCD) and chondrodystrophic (CD). In addition to a different process of endochondral ossification, NCD and CD breeds have different characteristics of intravertebral disc (IVD) degeneration and IVD degenerative diseases. The anatomy, physiology, histopathology, and biochemical and biomechanical characteristics of the healthy and degenerated IVD are discussed in the first part of this two-part review. This second part describes the similarities and differences in the histopathological and biochemical characteristics of IVD degeneration in CD and NCD canine breeds and discusses relevant aetiological factors of IVD degeneration.
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http://dx.doi.org/10.1016/j.tvjl.2012.10.011DOI Listing
March 2013

Design, synthesis, imaging, and biomechanics of a softness-gradient hydrogel nucleus pulposus prosthesis in a canine lumbar spine model.

J Biomed Mater Res B Appl Biomater 2012 Nov 9;100(8):2148-55. Epub 2012 Aug 9.

Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.

A hydrogel nucleus pulposus prosthesis (NPP) was designed to swell in situ, have intrinsic radiopacity, and restore intervertebral disc height and biomechanical functionality. These features were examined using an ex vivo canine lumbar model. Nine NPPs were implanted in five spines and their visibility was assessed on radiography, computed tomography (CT), and magnetic resonance imaging (MRI). The NPPs were visible on all imaging modalities and 8/9 NPPs stayed intact and in situ. Six other NPPs were tested biomechanically in six canine lumbar spines. Removal of the nucleus pulposus (nuclectomy) caused significant changes in biomechanical parameters. After implantation and swelling of the NPP, values were not significantly different from the native state for range of motion (ROM) of flexion-extension (FE) and lateral bending (LB), the neutral zone (NZ) of all motion directions, and the NZ stiffness (NZS) of FE. Biomechanical restoration by the NPP compared with the nuclectomized state was significant for the ROM of FE and axial rotation, the NZ of FE and LB, and the NZS of FE and LB. Disc height was significantly restored and 6/6 NPPs stayed intact and in situ. In conclusion, the NPPs swell in situ, have intrinsic radiopacity and restored disc height and aforementioned biomechanical properties.
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http://dx.doi.org/10.1002/jbm.b.32780DOI Listing
November 2012

Pedicle screw-rod fixation of the canine lumbosacral junction.

Vet Surg 2012 Aug 23;41(6):720-32. Epub 2012 Jul 23.

Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.

Objective: To assess pedicle screw-rod fixation (PSRF) of the canine lumbosacral junction (LSJ) ex vivo and in vivo.

Study Design: Ex vivo cadaver study and in vivo pilot study.

Sample Population: Six canine cadaveric lumbosacral spinal specimens and 3 Greyhound dogs diagnosed with degenerative lumbosacral stenosis (DLSS).

Methods: Ex vivo study: PSRF of the LSJ was performed in 6 spinal specimens using guidelines and was evaluated by radiography, computed tomography, and magnetic resonance imaging. In vivo study: 3 Greyhounds diagnosed with DLSS had dorsal laminectomy and partial discectomy combined with PSRF of the LSJ. Curettage of the endplates with insertion of an autologous cancellous bone graft was performed to promote spinal fusion. During 18-month follow-up, dogs were monitored by clinical evaluation, diagnostic imaging, and force plate analysis. Dogs were euthanatized for reasons unrelated to PSRF or their lumbosacral disease, and postmortem imaging and histopathologic investigations of the LSJ were performed.

Results: Ex vivo study: Sixteen of 24 inserted screws had an acceptable placement. In vivo study: Ten of 12 inserted screws had acceptable placement. Clinical signs of ``lower'' back pain resolved at 4 weeks after surgery. Diagnostic imaging and histopathology showed no bony spinal fusion of the LSJ. Force plate analysis revealed a trend toward improved pelvic limb function relative to preoperative function.

Conclusions: PSRF of the LSJ of large breed dogs is technically possible. Improvements to the surgical technique to induce spinal fusion and assessment in a larger sample size are required before it can be recommended.
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http://dx.doi.org/10.1111/j.1532-950X.2012.00989.xDOI Listing
August 2012

Intervertebral disc disease in dogs - part 2: comparison of clinical, magnetic resonance imaging, and histological findings in 74 surgically treated dogs.

Vet J 2013 Feb 12;195(2):164-71. Epub 2012 Jul 12.

Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 108, 3584 CM Utrecht, The Netherlands.

The relationship between intervertebral disc (IVD) disease and IVD degeneration remains unclear. The aim of the present study was to compare the clinical severity of IVD herniation (IVDH), determined with a neurological grading system, with findings of magnetic resonance imaging (MRI) and histology using grading systems for IVD degeneration in chondrodystrophic (CD; n=37) and non-chondrodystrophic (NCD; n=37) dogs. This study is the second part of a two-part investigation, where the first part involved the development and validation of a histological grading scheme for classification of canine IVD degeneration. IVD degeneration graded on MRI correlated significantly with IVD degeneration graded on histology, but not with pre-operative clinical signs. Hansen type 1 hernias were more common in the cervical and thoracolumbar segments and Hansen type 2 hernias were more common in the lumbosacral segment. Type 1 hernias occurred more often in CD dogs than in NCD dogs, and CD dogs were clinically more severely affected than NCD dogs. The grade of IVD degeneration on MRI was higher in CD dogs than in NCD dogs, but there was no difference between dogs with type 1 and type 2 hernias. No significant differences in histological grade were found between CD and NCD dogs or between type 1 and type 2 hernias. It was possible to conclude that IVD degeneration did not correlate with the neurological severity of IVDH. The extent of degeneration identified on MRI correlated with degeneration seen histologically. Although the MRI grading system reflected the severity of IVD degenerative changes as confirmed by histopathology, it appeared less useful in predicting the clinical implications.
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http://dx.doi.org/10.1016/j.tvjl.2012.06.001DOI Listing
February 2013

Incidence of intervertebral disk degeneration-related diseases and associated mortality rates in dogs.

J Am Vet Med Assoc 2012 Jun;240(11):1300-9

Department of Clinical Sciences, Faculty of Veterinary Medicine and Animal Sciences, Swedish University of Agricultural Sciences, 756 51 Uppsala, Sweden.

Objective: To determine the incidence and distribution of intervertebral disk (IVD) degeneration-related diseases in a large population of dogs of various breeds, ages, and sexes and to determine mortality rates among dogs with these diseases.

Design: Epidemiological study.

Sample: Insurance data for dogs with veterinary health-care and life insurance coverage (n = 665,249 and 552,120, respectively).

Procedures: Insurance claim records of 1 company in Sweden were searched to identify dogs with IVD degeneration-related diseases; incidence and mortality rates were determined for affected dogs < 12 years old and < 10 years old, respectively. Only the first paid IVD degeneration-related claim for a dog was included in incidence rate calculations.

Results: The incidence rate of IVD degeneration-related diseases was 27.8 (95% confidence interval [CI], 27.2 to 28.4) occurrences/10,000 dog-years at risk (DYAR), indicating that approximately 0.3% of dogs/y in this population were affected. Miniature Dachshund was the most highly represented breed, followed by Standard Dachshund and Doberman Pinscher (237.1 [95% CI, 212.9 to 261.4], 141.5 [95% CI, 135.5 to 147.4], and 88.6 [95% CI, 72.1 to 105.2] occurrences/10,000 DYAR, respectively). The incidence rate of IVD degeneration-related disease was greater in male than in female dogs and increased with age. Overall mortality rate attributed to IVD degeneration-related diseases was 9.4 (95% CI, 8.9 to 9.8) deaths/10,000 DYAR and was greater in males than in females.

Conclusions And Clinical Relevance: Differences in incidence rates among various breeds suggested a genetic involvement. Knowledge of the distribution of IVD degeneration-related diseases among dogs of various breeds and ages may facilitate early diagnosis and preemptive treatments in patients at risk for developing these diseases.
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http://dx.doi.org/10.2460/javma.240.11.1300DOI Listing
June 2012

A differential effect of bone morphogenetic protein-2 and vascular endothelial growth factor release timing on osteogenesis at ectopic and orthotopic sites in a large-animal model.

Tissue Eng Part A 2012 Oct 12;18(19-20):2052-62. Epub 2012 Sep 12.

Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands.

In bone tissue engineering, growth factors are widely used. Bone morphogenetic proteins (BMPs) and vascular endothelial growth factor (VEGF) are the most well-known regulators of osteogenesis and angiogenesis. We investigated whether the timing of dual release of VEGF and BMP-2 influences the amount of bone formation in a large-animal model. Poly(lactic-co-glycolic acid) (PLGA) microparticles (MPs) were loaded with BMP-2 or VEGF to create sustained-release profiles, and rapidly degrading gelatin was loaded with either growth factor for fast-release profiles. To study in vivo osteogenicity, the two delivery vehicles were combined with biphasic calcium phosphate (BCP) scaffolds and implanted in 10 Beagle dogs for 9 weeks, at both ectopic (paraspinal muscles) and orthotopic sites (critical-size ulnar defect). The 9 ectopic groups contained combined or single BMP/VEGF dosage, in sustained- or fast-release profiles. In the ulnae of 8 dogs, fast VEGF and sustained BMP-2 were applied to one leg, and the other received the opposite release profiles. The two remaining dogs received bilateral control scaffolds. Bone growth dynamics was analyzed by fluorochrome injection at weeks 3, 5, and 7. Postoperative and posteuthanization X-rays of the ulnar implants were taken. After 9 weeks of implantation, bone quantity and bone growth dynamics were studied by histology, histomorphometry, and fluorescence microscopy. The release of the growth factors resulted in both enhanced orthotopic and ectopic bone formation. Bone formation started before 3 weeks and continued beyond 7 weeks. The ectopic BMP-2 fast groups showed significantly more bone compared to sustained release, independent of the VEGF profile. The ulna implants revealed no significant differences in the amount of bone formed. This study shows that timing of BMP-2 release largely determines speed and amount of ectopic bone formation independent of VEGF release. Furthermore, at the orthotopic site, no significant effect on bone formation was found from a timed release of growth factors, implicating that timed-release effects are location dependent.
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http://dx.doi.org/10.1089/ten.TEA.2011.0560DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3463278PMC
October 2012

Biomechanical assessment of the effects of decompressive surgery in non-chondrodystrophic and chondrodystrophic canine multisegmented lumbar spines.

Eur Spine J 2012 Sep 11;21(9):1692-9. Epub 2012 Apr 11.

Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 108, PO Box 80.154, 3508 TD, Utrecht, The Netherlands.

Purpose: Dogs are often used as an animal model in spinal research, but consideration should be given to the breed used as chondrodystrophic (CD) dog breeds always develop IVD degeneration at an early age, whereas non-chondrodystrophic (NCD) dog breeds may develop IVD degeneration, but only later in life. The aim of this study was to provide a mechanical characterization of the NCD [non-degenerated intervertebral discs (IVDs), rich in notochordal cells] and CD (degenerated IVDs, rich in chondrocyte-like cells) canine spine before and after decompressive surgery (nucleotomy).

Methods: The biomechanical properties of multisegmented lumbar spine specimens (T13-L5 and L5-Cd1) from 2-year-old NCD dogs (healthy) and CD dogs (early degeneration) were investigated in flexion/extension (FE), lateral bending (LB), and axial rotation (AR), in the native state and after nucleotomy of L2-L3 or dorsal laminectomy and nucleotomy of L7-S1. The range of motion (ROM), neutral zone (NZ), and NZ stiffness (NZS) of L1-L2, L2-L3, L6-L7, and L7-S1 were calculated.

Results: In native spines in both dog groups, the greatest mobility in FE was found at L7-S1, and the greatest mobility in LB at L2-L3. Surgery significantly increased the ROM and NZ, and significantly decreased the NZS in FE, LB, and AR in both breed groups. However, surgery at L2-L3 resulted in a significantly larger increase in NZ and decrease in NZS in the CD spines compared with the NCD spines, whereas surgery at L7-S1 induced a significantly larger increase in ROM and decrease in NZS in the NCD spines compared with the CD spines.

Conclusions: Spinal biomechanics significantly differ between NCD and CD dogs and researchers should consider this aspect when using the dog as a model for spinal research.
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http://dx.doi.org/10.1007/s00586-012-2285-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3459126PMC
September 2012

Canonical Wnt signaling in the notochordal cell is upregulated in early intervertebral disk degeneration.

J Orthop Res 2012 Jun 14;30(6):950-7. Epub 2011 Nov 14.

Department of Clinical Sciences of Companion Animals, Utrecht University, Yalelaan 108, 3508 TD, Utrecht, The Netherlands.

The notochordal cell (NC) of the nucleus pulposus (NP) is considered a potential NP progenitor cell, and early intervertebral disk (IVD) degeneration involves replacement of NCs by chondrocyte-like cells (CLCs). Wnt/β-catenin signaling plays a crucial role in maintaining the notochordal fate during embryogenesis, but is also involved in tissue degeneration and regeneration. The canine species, which can be subdivided into non-chondrodystrophic and chondrodystrophic breeds, is characterized by differential maintenance of the NC: in non-chondrodystrophic dogs, the NC remains the predominant cell type during the majority of life, with IVD degeneration only occurring at old age; conversely, in chondrodystrophic dogs the NC is lost early in life, with concurrent degeneration of all IVDs. This study investigated Wnt/β-catenin signaling in the healthy, NC-rich NP and early degenerated, CLC-rich NP of both breed types by immunohistochemistry of β-catenin and relative gene expression of brachyury and cytokeratin 8 (notochordal markers) and Wnt targets axin2, cyclin D1, and c-myc. Both NCs and CLCs showed nuclear and cytoplasmic β-catenin protein expression and axin2 gene expression, but β-catenin signal intensity and Wnt target gene expression were higher in the CLC-rich NP. Primary NCs in monolayer culture (normoxic conditions) showed Wnt/β-catenin signaling comparable to the in vivo situation, with increased cyclin D1 and c-myc gene expression. In conclusion, Wnt/β-catenin signaling activity in the NC within the NC-rich NP and in culture supports the role of this cell as a potential progenitor cell; increased Wnt/β-catenin signaling activity in early IVD degeneration may be a reflection of its dual role.
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http://dx.doi.org/10.1002/jor.22000DOI Listing
June 2012

Reliability of macroscopic grading of intervertebral disk degeneration in dogs by use of the Thompson system and comparison with low-field magnetic resonance imaging findings.

Am J Vet Res 2011 Jul;72(7):899-904

Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, 3508 TD Utrecht, The Netherlands.

Objective: To evaluate the reliability of the Thompson system for use in grading the gross pathological changes of intervertebral disk (IVD) degeneration in dogs and to investigate the agreement between gross pathological findings and low-field (0.2-T) magnetic resonance imaging (MRI) findings.

Sample: Vertebral columns from cadavers of 19 dogs of various ages, breeds, and origins.

Procedures: 182 intervertebral segments were collected from 19 canine cadavers. Sagittal T2-weighted MRI of the T11 through S1 portion of the vertebral column was performed within 24 hours after the dogs were euthanized. The vertebral columns were subsequently divided in the midsagittal plane, and high-resolution photographs were obtained of each intervertebral segment (end plate-disk-end plate). The MRI images and photographs were graded separately in a blinded manner by 4 observers who used both Pfirrmann and Thompson grading criteria.

Results: The interobserver agreement for Thompson scores ranged from 0.76 to 0.88, and the intraobserver agreement ranged from 0.88 to 0.94 (Cohen weighted κ analysis). Agreement between scores for the Pfirrmann and Thompson grading criteria was κ = 0.70.

Conclusions And Clinical Relevance: Grading of IVD degeneration in dogs by use of the Thompson system resulted in high interobserver and intraobserver agreement, and scores for the Thompson system had substantial agreement with low-field MRI findings graded by use of the Pfirrmann system. This suggested that low-field MRI can be used to diagnose IVD degeneration in dogs.
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http://dx.doi.org/10.2460/ajvr.72.7.899DOI Listing
July 2011

Evaluation of intervertebral disk degeneration in chondrodystrophic and nonchondrodystrophic dogs by use of Pfirrmann grading of images obtained with low-field magnetic resonance imaging.

Am J Vet Res 2011 Jul;72(7):893-8

Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, 3508 TC Utrecht, The Netherlands.

Objective: To assess whether the Pfirrmann system for grading lumbar intervertebral disk (IVD) degeneration in humans can also be used in dogs.

Animals: 202 dogs.

Procedures: Magnetic resonance imaging was used to obtain images of vertebral segments from dogs, which were reviewed separately by 3 observers who graded the extent of degeneration in each visible IVD by use of the Pfirrmann classification system used for grading lumbar IVD degeneration in humans. Grading was validated against 2 factors associated with the extent of disk degeneration: type of dog (chondrodystrophic or nonchondrodystrophic breeds) and age.

Results: Interobserver and intraobserver agreement for Pfirrmann grading of IVD degeneration were good (κ scores, 0.81 to 0.93). An increase in the extent of disk degeneration was positively correlated with increases in age and with chondrodystrophic breed.

Conclusions And Clinical Relevance: The Pfirrmann system was reliably used to grade IVD degeneration in dogs of various breeds and ages. An increase in the extent of IVD degeneration was positively correlated with increases in age and with chondrodystrophic-type dogs.
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http://dx.doi.org/10.2460/ajvr.72.7.893DOI Listing
July 2011

Diffuse idiopathic skeletal hyperostosis (DISH) and spondylosis deformans in purebred dogs: a retrospective radiographic study.

Vet J 2011 Nov 14;190(2):e84-e90. Epub 2011 May 14.

Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 108, 3584 CM Utrecht, The Netherlands.

A retrospective radiographic study was performed to investigate the prevalence of diffuse idiopathic skeletal hyperostosis (DISH) and spondylosis deformans (spondylosis) in 2041 purebred dogs and to determine association with age, gender and breed. Four cases of DISH provided information on the appearance of canine DISH. The prevalence of DISH and spondylosis was 3.8% (78/2041) and 18.0% (367/2041), respectively. Of dogs with DISH, 67.9% (53/78) also had spondylosis, whereas 14.0% (53/367) of dogs with spondylosis also had DISH. Dogs with DISH and/or spondylosis were significantly older than those without spinal exostosis. The prevalence of DISH and spondylosis was 40.6% (28/69) and 55.1% (38/69), respectively, in Boxer dogs. Nineteen smaller breeds were not affected by DISH, but showed signs of spondylosis; only standard Poodles appeared not to be affected by either disorder. Radiography, computed tomography (CT), magnetic resonance imaging (MRI), and/or histopathology were used to investigate four DISH cases. It was concluded that spondylosis and DISH can co-occur in dogs. DISH has probably been previously under-diagnosed and mistaken for severe spondylosis. The diagnosis can be made using radiography, CT or MRI. On histology, DISH can be distinguished from spondylosis by the location (ventral longitudinal ligament) and extent of new bone formation.
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http://dx.doi.org/10.1016/j.tvjl.2011.04.008DOI Listing
November 2011

The dog as an animal model for intervertebral disc degeneration?

Spine (Phila Pa 1976) 2012 Mar;37(5):351-8

Department of Clinical Sciences of Companion Animals, Utrecht University, Utrecht, The Netherlands.

Study Design: Prospective observational and analytic study.

Objective: To investigate whether spontaneous intervertebral disc degeneration (IVDD) occurring in both chondrodystrophic (CD) and nonchondrodystrophic dogs (NCD) can be used as a valid translational model for human IVDD research.

Summary Of Background Data: Different animal models are used in IVDD research, but in most of these models IVDD is induced manually or chemically rather than occurring spontaneously.

Methods: A total of 184 intervertebral discs (IVDs) from 19 dogs of different breeds were used. The extent of IVDD was evaluated by macroscopic grading, histopathology, glycosaminoglycan content, and matrix metalloproteinase 2 activity. Canine data were compared with human IVD data acquired in this study or from the literature.

Results: Gross pathology of IVDD in both dog types (CD and NCD) and humans showed many similarities, but the cartilaginous endplates were significantly thicker and the subchondral cortices significantly thinner in humans than in dogs. Notochordal cells were still present in the IVDs of adult NCD but were not seen in the CD breeds or in humans. Signs of degeneration were seen in young dogs of CD breeds (<1 year of age), whereas this was only seen in older dogs of NCD breeds (5-7 years of age). The relative glycosaminoglycan content and metalloproteinase 2 activity in canine IVDD were similar to those in humans: metalloproteinase 2 activity increased and glycosaminoglycan content decreased with increasing severity of IVDD.

Conclusion: IVDD is similar in humans and dogs. Both CD and NCD breeds may therefore serve as models of spontaneous IVDD for human research. However, as with all animal models, it is important to recognize interspecies differences and, indeed, the intraspecies differences between CD and NCD breeds (early vs. late onset of IVDD, respectively) to develop an optimal canine model of human IVDD.
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http://dx.doi.org/10.1097/BRS.0b013e31821e5665DOI Listing
March 2012

Evaluation of radiographic and genetic aspects of hereditary subluxation of the radial head in Bouviers des Flandres.

Am J Vet Res 2010 Aug;71(8):884-90

Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, 3584 CM, Utrecht, The Netherlands.

Objective: To study radiographic and genetic aspects of hereditary radial head subluxation in Bouviers des Flandres.

Animals: 26 related Bouviers des Flandres affected with bilateral subluxation of the radial head, 10 unaffected related dogs, and 29 unrelated Bouviers des Flandres with diagnoses of nonskeletal diseases.

Procedures: All dogs were radiographically studied, and their DNA was analyzed with a genome-wide screen of 1,536 single nucleotide polymorphisms. In addition, karyotyping was performed in an unaffected dam and its affected offspring.

Results: Both forelimbs of affected dogs were disproportionately short with caudolateral subluxation or luxation of the radial head. Angulation of the radial axis at the mid-diaphysis ranged from 9.3 degrees to 30.3 degrees (mean +/- SD, 14.9 +/- 6.1 degrees ), with an estimated age of onset from 0 to 4 months. Poorly defined medial coronoid processes and osteoarthritis of the elbow joint, cranial bowing of the olecranon, and disturbed growth in length of the ulna with sharply demarcated spurs were noticed on radiographs of affected dogs. Genealogical analysis indicated that most affected dogs were closely related, but the mode of inheritance was not clear. The DNA analysis found that 205 single nucleotide polymorphisms were monomorphic in the affected dogs. Conventional chromosome staining revealed no numerical chromosomal aberration.

Conclusions And Clinical Relevance: Congenital radial head luxation and subluxation in the studied Bouviers des Flandres were characterized by angulation of the radial axis leading to caudolateral subluxation of the radial head and insufficient growth of the distal portion of the ulna together with cranial bowing of the olecranon.
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http://dx.doi.org/10.2460/ajvr.71.8.884DOI Listing
August 2010

The performance of a hydrogel nucleus pulposus prosthesis in an ex vivo canine model.

Biomaterials 2010 Sep 12;31(26):6782-8. Epub 2010 Jun 12.

Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, PO Box 80.154, NL-3508 TD, Utrecht, The Netherlands.

A nucleus pulposus prosthesis (NPP) made of the hydrogel N-vinyl-2-pyrrolidinone copolymerized with 2-(4'-iodobenzoyl)-oxo-ethyl methacrylate has recently been developed. The special features of this NPP, i.e. intrinsic radiopacity and its ability to swell in situ to fill the nucleus cavity and restore disc height, were investigated ex vivo in canine spinal specimens. L7-S1 intervertebral discs were isolated from three canine spinal specimens, and the dimensions of the nuclei pulposi were measured. Based on these averaged measurements, the NPP prototype was made and inserted in its dry form (xerogel) into a canine cadaveric spinal segment and allowed to swell overnight at 38 degrees C. The integrity of the NPP and the filling of the nucleus cavity were assessed before and after swelling, using radiography, computed tomography, and magnetic resonance imaging. The ability of the NPP to restore disc height was assessed on radiographs of 10 spinal specimens. Thereafter the NPP was macroscopically assessed in situ by dissection of the spinal specimen. Both on imaging and macroscopically, 9/10 NPPs appeared to have a near perfect fit and disc height was restored in 8/10 spinal segments. The NPP may thus be an acceptable treatment option for low back patients meeting the requirements for NPP treatment.
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http://dx.doi.org/10.1016/j.biomaterials.2010.05.032DOI Listing
September 2010

Bone scintigraphy for the diagnosis of an abnormal medial coronoid process in dogs.

Vet Radiol Ultrasound 2010 May-Jun;51(3):344-8

Division of Diagnostic Imaging, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.

Few reports have been published regarding the use of scintigraphy in the diagnosis of elbow joint lameness in dogs. Some authors have speculated about the potential use of bone scintigraphy and its suspected high sensitivity for the early diagnosis of abnormalities of the medial coronoid process (MCP) in dogs. Scintigraphy is used routinely in our institution in dogs presented for thoracic limb lameness and/or suspected of abnormalities of the MCP when radiographic findings were equivocal. Radiographic, scintigraphic, and surgical findings of the elbow joints of 17 dogs with elbow joint lameness were compared with radiographic, scintigraphic, and necropsy findings of the elbow joints of 12 clinically healthy Labrador Retrievers. Quantitative evaluation of scintigraphic images was performed to determine relative radiopharmaceutical uptake in the region of the MCP. Maximum relative uptake of the coronoid process in the normal dogs was taken as a threshold value to classify elbows as positive or negative for an abnormal MCP after all 24 elbows of the 12 healthy dogs were confirmed as being normal at necropsy. All 17 elbows from lame dogs were positive on scintigraphy and confirmed as having chondromalacia, a fissure, or fragmentation of the MCP. Based on our results, bone scintigraphy may be a valuable diagnostic tool for the diagnosis of abnormalities of the MCP in dogs, and particularly in older dogs where clinical and radiographic changes may be ambiguous.
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http://dx.doi.org/10.1111/j.1740-8261.2009.01664.xDOI Listing
June 2010

The effect of weight loss on lameness in obese dogs with osteoarthritis.

Vet Res Commun 2010 Mar 17;34(3):241-53. Epub 2010 Mar 17.

Small Animal Hospital, University of Glasgow Veterinary School, Bearsden Road, Glasgow, Scotland, UK.

This paper describes the effect of weight loss on lameness in obese dogs with osteoarthritis (OA). Fourteen obese client-owned dogs with clinical and radiographic signs of OA participated in an open prospective clinical trial. After a screening visit and a visit for collection of baseline data, the dogs were fed a restricted-calorie diet over a study period of 16 weeks that incorporated six follow-up visits. At each visit, body weight and pelvic circumference were measured and severity of lameness was assessed using a numeric rating scale (NRS), a visual analogue scale (VAS) and kinetic gait analysis. This is the first study to assess both subjectively and objectively, the effect of weight loss alone on lameness in obese dogs with OA. The results indicate that body weight reduction causes a significant decrease in lameness from a weight loss of 6.10% onwards. Kinetic gait analysis supported the results from a body weight reduction of 8.85% onwards. These results confirm that weight loss should be presented as an important treatment modality to owners of obese dogs with OA and that noticeable improvement may be seen after modest weight loss in the region of 6.10 - 8.85% body weight.
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http://dx.doi.org/10.1007/s11259-010-9348-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2855019PMC
March 2010

Increased vitamin D-driven signalling and expression of the vitamin D receptor, MSX2, and RANKL in tooth resorption in cats.

Eur J Oral Sci 2010 Feb;118(1):39-46

Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands.

Tooth resorption occurs in 20-75% of cats (Felis catus). The aetiology is not known, but vitamin D is suggested to be involved. Vitamin D acts through a nuclear receptor (VDR) and increases the expression of receptor activator of nuclear factor-kappaB ligand (rankl) and muscle segment homeobox 2 (msx2) genes. Mice lacking the muscle segment homeobox 2 (msx2) gene show decreased levels of rankl, suggesting an interaction among VDR, MSX2, and RANKL. Here, we investigated the expression of VDR, MSX2, and RANKL proteins, and the activity of the VDR-mediated signalling pathway (using the quantitative polymerase chain reaction on VDR target genes), in tooth resorption, and measured the serum levels of vitamin D metabolites in cats. Tooth resorption was categorized into either resorptive or reparative stages. In the resorptive stage, odontoclasts expressed MSX2 and RANKL (100% and 88%, respectively) and fibroblasts expressed VDR and MSX2 (both at 100%), whereas fibroblasts expressed RANKL in only 29% of the sites analysed. In the reparative stage, cementoblasts expressed VDR, MSX2, and RANKL, whereas fibroblasts expressed VDR and MSX2, but not RANKL. The vitamin D status did not differ between the groups, based on the serum levels of 25-hydroxycholecalciferol. However, increased expression of VDR protein, and the relative gene expression levels of 1alpha-hydroxylase and the VDR-target gene, 24-hydroxylase, indicated the involvement of an active vitamin D signalling in the pathophysiology of tooth resorption in cats.
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http://dx.doi.org/10.1111/j.1600-0722.2009.00707.xDOI Listing
February 2010

Evaluation of candidate genes as a cause of chondrodysplasia in Labrador retrievers.

Vet J 2011 Feb 16;187(2):269-71. Epub 2009 Dec 16.

Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, PO Box 80154, 3508 TD Utrecht, The Netherlands.

Chondrodysplasia (CD) is a disabling, hereditary disease in Labradors with short limbs, warranting genetic screening in families at risk. Segregation analysis of eight litters with 13 affected dogs showed that autosomal recessive inheritance was consistent with the observed incidence of CD in the litters. Possible involvement of eight candidate collagen genes (COL9A1, COL9A2, COL9A3, COMP, MATN3, COL2A1, COL11A1 and COL11A2) and of a sulfate transporter glycoprotein (SLC26A2) gene in eight affected dogs and in 14 related control Labradors was investigated. Assuming recessive inheritance, the candidate genes could not be implicated in CD.
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http://dx.doi.org/10.1016/j.tvjl.2009.11.009DOI Listing
February 2011

Fragmented coronoid process in the dog: a heritable disease.

Vet J 2010 Aug 28;185(2):123-9. Epub 2009 Jul 28.

Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 108, P.O. Box 80154, 3508 TD Utrecht, The Netherlands.

Fragmented coronoid process (FCP) is one of the main diseases associated with elbow dysplasia. FCP is often diagnosed in medium-to-large breed dogs with front leg lameness, for instance in Rottweilers, Labrador Retrievers and Bernese Mountain dogs. Dogs with FCP develop osteoarthrosis of the elbow joint despite conservative or surgical treatment. Although FCP is considered a hereditary condition, the gene or genes causing FCP have yet to be identified. This article provides an overview of different aspects of FCP, including elbow joint development, hypotheses about disease pathogenesis, the genetic background of FCP, and genetic methodology to identify gene or genes responsible for FCP.
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http://dx.doi.org/10.1016/j.tvjl.2009.06.022DOI Listing
August 2010

Inflammatory cytokines and the nuclear vitamin D receptor are implicated in the pathophysiology of dental resorptive lesions in cats.

Vet Immunol Immunopathol 2009 Dec 6;132(2-4):160-6. Epub 2009 Jun 6.

Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 108, PO Box 80154, 3508 TD Utrecht, The Netherlands.

Dental resorptive lesions (RL) are a common oral disease in cats (Felis catus) associated with pain and tooth destruction. The aetiology of RL in cats is unknown, but inflammation is often seen in conjunction with RL. Vitamin D involvement has been suggested because 1,25-dihydroxyvitamin D (1,25(OH)(2)D) stimulates osteoclastogenesis, through up-regulation of the nuclear vitamin D receptor (nVDR). The aim of this study is to determine the involvement of inflammatory cytokines and the possible role of vitamin D in the pathophysiology of RL using quantitative PCR. We measured the mRNA expression of cytokines with stimulatory (IL-1beta, IL-6, and TNF-alpha) and inhibitory effects (IL-10 and IFN-gamma) on osteoclastogenesis, and the mRNA expression of the receptor activator of nuclear factor-kappaB ligand (RANKL), osteoprotegerin (OPG), and nVDR in RL samples. We found increased expression of mRNA levels for inflammatory cytokines and nVDR, but not for RANKL and OPG, in tissue from RL-affected cats compared with tissue from radiological confirmed healthy controls. The mRNA levels of nVDR were positively correlated with mRNA levels of pro-inflammatory (IL-1beta, IL-6, TNF-alpha, and IFN-gamma), anti-inflammatory (IL-10), pro-resorptive (IL-1beta, IL-6, and TNF-alpha), and anti-resorptive (IFN-gamma and IL-10) cytokines in the course of resorptive lesions. These data are consistent with our view that both inflammation and an overexpression of the nVDR are likely to be involved in RL in cats.
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http://dx.doi.org/10.1016/j.vetimm.2009.05.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7127172PMC
December 2009

Biomechanical flexion-extension forces in normal canine lumbosacral cadaver specimens before and after dorsal laminectomy-discectomy and pedicle screw-rod fixation.

Vet Surg 2007 Dec;36(8):742-51

Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.

Objective: To determine biomechanical flexion-extension forces in cadaveric canine lumbosacral specimens, before and after dorsal laminectomy with partial discectomy, and after dorsal pedicle screw-rod fixation of L7 and S1.

Study Design: Biomechanical cadaver study.

Animals: Cadaveric spine specimens without lumbosacral pathology from mature, intact Labrador retrievers (n=12).

Methods: Lumbosacral spine segments were subjected to a constant bending moment from L6 to S1 in a hydraulic 4-point bending materials testing machine. Force and displacement were recorded during each loading cycle constituting 1 complete flexion-extension cycle of the spine. Each spine segment had 3 series of recordings of 5 loading cycles each: (1) intact spine, (2) after surgical destabilization by dorsal laminectomy and partial discectomy, and (3) after surgical stabilization using dorsal pedicle screw-rod fixation.

Results: After dorsal laminectomy and partial discectomy, the neutral zone and range of motion were not different from those in the native spine specimen. After pedicle screw-rod fixation, the neutral zone and range of motion of the instrumented specimen significantly (P<.0001) decreased compared with the native specimen and the specimen after dorsal laminectomy.

Conclusion: Dorsal laminectomy and partial discectomy does not lead to significant spinal instability in flexion and extension whereas pedicle screw and rod fixation effectively stabilizes the lumbosacral spine.

Clinical Relevance: Dorsal laminectomy and partial discectomy does not lead to significant spinal instability. Pedicle screw-rod fixation of L7 and S1 may be used to stabilize an unstable L7-S1 junction in dogs with degenerative lumbosacral stenosis.
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http://dx.doi.org/10.1111/j.1532-950X.2007.00331.xDOI Listing
December 2007

A validation of 10 feline reference genes for gene expression measurements in snap-frozen tissues.

Vet Immunol Immunopathol 2007 Dec 15;120(3-4):212-22. Epub 2007 Aug 15.

Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 104, PO Box 80154, 3508 TD Utrechet, The Netherlands.

For a proper determination of relative mRNA expression levels with real-time quantitative PCR (Q-PCR) internal standards, such as the expression of reference genes, are of utmost importance. For cats, in contrast to dogs, no validation of reference genes has been published. Our goal was to evaluate frequently used reference genes for the analysis of relative mRNA levels from feline tissues in a SYBR Green-based Q-PCR protocol. First, primers were optimized on mRNA-derived cDNA from liver and kidney tissues of randomly chosen (healthy and diseased) cats. Then, the expression variation and stability of each reference gene within a specific tissue was determined. Dental roots and crowns, heart (left ventricle), renal, liver, lung, and mammary gland tissues from 3 to 11 cats of different breeds, sexes, ages, and disease status were included in this study. Averaging relative stabilities over these six tissues revealed the usefulness of each tested gene as reference gene. In order to compensate for the expression variation of a reference gene within a specific tissue, as much as six reference genes (e.g. RPL17, RPL30, RPS7, YWHAZ, and HPRT) were required to obtain highly reliable data in cat tissues. The optimal set of reference genes depended on the tissue analyzed and should, ideally, be selected and evaluated at the start of each experimental condition. A comparison with a similar evaluation in dogs revealed three issues: (i) most ribosomal genes are suitable in both species; (ii) good non-ribosomal reference genes differ; (iii) more feline than canine reference genes are required for proper analysis.
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http://dx.doi.org/10.1016/j.vetimm.2007.08.006DOI Listing
December 2007

Assessment of decompressive surgery in dogs with degenerative lumbosacral stenosis using force plate analysis and questionnaires.

Vet Surg 2007 Jul;36(5):423-31

Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, The Netherlands.

Objective: To evaluate the long-term outcome after decompressive surgery in dogs with degenerative lumbosacral stenosis (DLS), using force plate analysis (FPA) and owner questionnaires.

Study Design: Prospective clinical study.

Animals: Dogs with DLS (n=31) and 24 clinically normal Labrador Retrievers.

Methods: FPA was performed before surgery (31 dogs) and at 3 days, 6 weeks, 6 months (each, 31 dogs) and >or=1.5 years (12 dogs) after surgery. Peak vertical forces (Fz(+)), braking (Fy(+)), and propulsive forces (Fy(-)), and the corresponding impulses were determined. Questionnaires were completed by the owners before and at 6 months and >or=1.5 years after surgery.

Results: Fy(-) of the pelvic limbs and the ratio pelvic/thoracic of Fy(-) (P/TFy(-)) were significantly smaller in dogs with DLS than controls. Fy(-) and P/TFy(-) decreased significantly 3 days after surgery, and increased during 6 months follow-up, but with long-term follow-up the values remained the same and were smaller than controls. From questionnaires there was a significant improvement after surgery compared with function before surgery. Most owners were satisfied with outcome after surgery.

Conclusions: Propulsive forces of the pelvic limbs in dogs with DLS are impaired and are partially restored by decompressive surgery.

Clinical Relevance: Owner's questionnaires illustrate that decompressive surgery restores function as perceived by owners whereas FPA continues to show impaired propulsive forces for the pelvic limbs.
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http://dx.doi.org/10.1111/j.1532-950X.2007.00288.xDOI Listing
July 2007