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Costa da Silva RG, Sun TC, Mishra AP, Boyde A, Doube M, Riggs CM. Intracortical remodelling increases in highly loaded bone after exercise cessation. J Anat 2024; 244:424-437. [PMID: 37953410 PMCID: PMC10862154 DOI: 10.1111/joa.13969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 10/18/2023] [Accepted: 10/18/2023] [Indexed: 11/14/2023] Open
Abstract
Resorption within cortices of long bones removes excess mass and damaged tissue and increases during periods of reduced mechanical loading. Returning to high-intensity exercise may place bones at risk of failure due to increased porosity caused by bone resorption. We used point-projection X-ray microscopy images of bone slices from highly loaded (metacarpal, tibia) and minimally loaded (rib) bones from 12 racehorses, 6 that died during a period of high-intensity exercise and 6 that had a period of intense exercise followed by at least 35 days of rest prior to death, and measured intracortical canal cross-sectional area (Ca.Ar) and number (N.Ca) to infer remodelling activity across sites and exercise groups. Large canals that are the consequence of bone resorption (Ca.Ar >0.04 mm2 ) were 1.4× to 18.7× greater in number and area in the third metacarpal bone from rested than exercised animals (p = 0.005-0.008), but were similar in number and area in ribs from rested and exercised animals (p = 0.575-0.688). An intermediate relationship was present in the tibia, and when large canals and smaller canals that result from partial bony infilling (Ca.Ar >0.002 mm2 ) were considered together. The mechanostat may override targeted remodelling during periods of high mechanical load by enhancing bone formation, reducing resorption and suppressing turnover. Both systems may work synergistically in rest periods to remove excess and damaged tissue.
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Affiliation(s)
| | - Tsim Christopher Sun
- Sydney School of Veterinary ScienceUniversity of SydneyCamperdownNew South WalesAustralia
| | - Ambika Prasad Mishra
- Department of Infectious Diseases and Public HealthCity University of Hong KongKowloonHong Kong
| | - Alan Boyde
- Barts and The London School of Medicine and DentistryQueen Mary University of LondonLondonUK
| | - Michael Doube
- Department of Infectious Diseases and Public HealthCity University of Hong KongKowloonHong Kong
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Costa da Silva RG, Mishra AP, Riggs CM, Doube M. Classification of racehorse limb radiographs using deep convolutional neural networks. Vet Rec Open 2023; 10:e55. [PMID: 36726400 PMCID: PMC9884469 DOI: 10.1002/vro2.55] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 12/07/2022] [Accepted: 12/16/2022] [Indexed: 01/30/2023] Open
Abstract
Purpose To assess the capability of deep convolutional neural networks to classify anatomical location and projection from a series of 48 standard views of racehorse limbs. Materials and methods Radiographs (N = 9504) of horse limbs from image sets made for veterinary inspections by 10 independent veterinary clinics were used to train, validate and test (116, 40 and 42 radiographs, respectively) six deep learning architectures available as part of the open source machine learning framework PyTorch. The deep learning architectures with the best top-1 accuracy had the batch size further investigated. Results Top-1 accuracy of six deep learning architectures ranged from 0.737 to 0.841. Top-1 accuracy of the best deep learning architecture (ResNet-34) ranged from 0.809 to 0.878, depending on batch size. ResNet-34 (batch size = 8) achieved the highest top-1 accuracy (0.878) and the majority (91.8%) of misclassification was due to laterality error. Class activation maps indicated that joint morphology, not side markers or other non-anatomical image regions, drove the model decision. Conclusions Deep convolutional neural networks can classify equine pre-import radiographs into the 48 standard views including moderate discrimination of laterality, independent of side marker presence.
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Affiliation(s)
| | - Ambika Prasad Mishra
- Department of Infectious Diseases and Public HealthCity University of Hong KongHong Kong SARChina
| | | | - Michael Doube
- Department of Infectious Diseases and Public HealthCity University of Hong KongHong Kong SARChina
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Rosanowski SM, MacEoin F, Graham RJTY, Riggs CM. Open standing castration in Thoroughbred racehorses in Hong Kong: Prevalence and severity of complications 30 days post-castration. Equine Vet J 2017; 50:327-332. [PMID: 28886223 DOI: 10.1111/evj.12758] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 08/06/2017] [Indexed: 11/29/2022]
Abstract
BACKGROUND Complications following open standing castration (OSC) in Thoroughbred racehorses are well recognised but variation in their prevalence and severity between populations is not well documented. OBJECTIVES To describe the prevalence and severity of complications in the 30 days following OSC. STUDY DESIGN A retrospective cohort study of veterinary clinical records relating to horses that underwent OSC between July 2007 and July 2012. METHODS Complications were graded on a severity score from N, no complications, to C3, severe complications. Additional data were accessed for each horse including age, import date, racing history, trainer and veterinarian performing the castration. Bacterial culture and antimicrobial sensitivities were performed on a limited number of castration wounds that became infected. RESULTS In total, 250 horses were castrated in Hong Kong using the OSC technique over the period of the study. Sixty percent (150/250) of horses experienced some type of post-castration complication, with eight horses experiencing a severe (C3) complication requiring intensive veterinary treatment. Scrotal swelling, funiculitis and seroma formation were present in 70.0%, 36.7% and 24.7% of cases respectively. Most horses experiencing complications required wound reopening (87.3%; 131/150), and/or an extended course of first-line antimicrobials and/or nonsteroidal anti-inflammatory drugs (75/150; 50.0%). Eight horses had cultures submitted for bacterial sensitivity, with 17 bacterial isolates grown. In vitro, the bacteria cultured were sensitive to enrofloxacin (76%; 13/17) and ceftiofur (100%; 17/17). Resistance was detected to penicillin, gentamicin, oxytetracycline, metronidazole and trimethoprim-sulfadiazine. MAIN LIMITATIONS Differences in post-castration management cannot be accounted for in this study. CONCLUSIONS Complications following OSC in horses in Hong Kong were common. The majority were mild and were successfully treated using antimicrobials and simple wound management. Given the high rate of complications and antimicrobial usage identified in this study, a review of the technique is warranted.
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Affiliation(s)
- S M Rosanowski
- Royal Veterinary College, Hatfield, Hertfordshire, UK.,City University of Hong Kong, College of Veterinary Medicine and Life Sciences - Department of Infectious Diseases and Public Health, Kowloon Tong, Hong Kong SAR, Hong Kong
| | - F MacEoin
- Galway Equine Clinic, Galway, Ireland
| | - R J T Y Graham
- University of Edinburgh, Royal Dick School of Veterinary Studies - Equine Hospital, Roslin, Midlothian, UK
| | - C M Riggs
- Hong Kong Jockey Club - Veterinary Clinical Services, Equine Hospital, Hong Kong SAR, Hong Kong
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Peffers MJ, McDermott B, Clegg PD, Riggs CM. Comprehensive protein profiling of synovial fluid in osteoarthritis following protein equalization. Osteoarthritis Cartilage 2015; 23:1204-13. [PMID: 25819577 PMCID: PMC4528073 DOI: 10.1016/j.joca.2015.03.019] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 01/30/2015] [Accepted: 03/16/2015] [Indexed: 02/02/2023]
Abstract
OBJECTIVE The aim of the study was to characterise the protein complement of synovial fluid (SF) in health and osteoarthritis (OA) using liquid chromatography mass spectrometry (LC-MS/MS) following peptide-based depletion of high abundance proteins. DESIGN SF was used from nine normal and nine OA Thoroughbred horses. Samples were analysed with LC-MS/MS using a NanoAcquity™ LC coupled to an LTQ Orbitrap Velos. In order to enrich the lower-abundance protein fractions protein equalisation was first undertaken using ProteoMiner™. Progenesis-QI™ LC-MS software was used for label-free quantification. In addition immunohistochemistry, western blotting and mRNA expression analysis was undertaken on selected joint tissues. RESULTS The number of protein identifications was increased by 33% in the ProteoMiner™ treated SF compared to undepleted SF. A total of 764 proteins (462 with≥2 significant peptides) were identified in SF. A subset of 10 proteins were identified which were differentially expressed in OA SF. S100-A10, a calcium binding protein was upregulated in OA and validated with western blotting and immunohistochemistry. Several new OA specific peptide fragments (neopeptides) were identified. CONCLUSION The protein equalisation method compressed the dynamic range of the synovial proteins identifying the most comprehensive SF proteome to date. A number of proteins were identified for the first time in SF which may be involved in the pathogenesis of OA. We identified a distinct set of proteins and neopeptides that may act as potential biomarkers to distinguish between normal and OA joints.
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Affiliation(s)
- M J Peffers
- Comparative Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Leahurst, Chester High Road, Neston, Wirral, CH64 7TE, UK.
| | - B McDermott
- Comparative Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Leahurst, Chester High Road, Neston, Wirral, CH64 7TE, UK.
| | - P D Clegg
- Comparative Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Leahurst, Chester High Road, Neston, Wirral, CH64 7TE, UK.
| | - C M Riggs
- Hong Kong Jockey Club, Equine Hospital, Sha Tin Racecourse, New Territories, Hong Kong.
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Preston S, Riggs CM. Descriptive analysis of longitudinal endoscopy for exercise-induced pulmonary haemorrhage in Thoroughbred racehorses training and racing at the Hong Kong Jockey Club - letter. Equine Vet J 2015; 47:374-5. [PMID: 25597337 DOI: 10.1111/evj.12388] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- S Preston
- Department of Veterinary Science, University of Kentucky, USA
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Pinchbeck GL, Clegg PD, Boyde A, Barr ED, Riggs CM. Horse-, training- and race-level risk factors for palmar/plantar osteochondral disease in the racing Thoroughbred. Equine Vet J 2013; 45:582-6. [PMID: 23425384 PMCID: PMC3883097 DOI: 10.1111/evj.12038] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 12/07/2012] [Indexed: 11/29/2022]
Abstract
Reasons for performing study Palmar/plantar osteochondral disease (POD) is a common, debilitating condition in Thoroughbred racehorses; however, training- and racing-related factors associated with this disease are unknown. Objectives To determine horse-, racing- and training-related risk factors for POD. The general hypotheses were that early training and racing, and increased intensity of racing and training, lead to increased severity of POD. Methods The metacarpo/metatarsophalangeal joints of 164 Thoroughbred racehorses were examined at post mortem and graded for third metacarpal and metatarsal POD. The relationships between training- and racing-related factors and grade of POD in each condyle were determined using multilevel, multivariable, ordinal logistic regression models. Results A total of 1288 condyles were graded. Factors associated with higher grades of POD were the total lifetime number of races, an increase in gallop sessions in the previous season, racing before import to Hong Kong and an increase in the number of short (8–16 weeks) between-race intervals per season. Horses in their first racing season were more likely to have lower POD grades, while horses that had a long between-race interval (greater than 16 weeks) in the season prior to euthanasia were also more likely to have lower POD grades. Lower POD grades were significantly more likely as days since last race increased up to 400 days. Age at first race was not significantly associated with grade of POD. Conclusions and potential relevance Cumulative racing exposure and training intensity in the previous season were associated with higher grades of POD, supporting the hypothesis that the disease is due to repetitive loading. Longer between-race intervals and increased time since racing were associated with lower POD grades, which may indicate that lesions heal. Further work is required to enable optimisation of racing and training programmes to reduce the frequency and severity of this disease.
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Affiliation(s)
- G L Pinchbeck
- Institute of Infection and Global Health, Faculty of Health and Life Sciences, University of Liverpool, UK.
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Pinchbeck GL, Clegg PD, Boyde A, Riggs CM. Pathological and clinical features associated with palmar/plantar osteochondral disease of the metacarpo/metatarsophalangeal joint in Thoroughbred racehorses. Equine Vet J 2013; 45:587-92. [PMID: 23418959 DOI: 10.1111/evj.12036] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 12/07/2012] [Indexed: 11/30/2022]
Abstract
REASONS FOR PERFORMING STUDY Palmar/plantar osteochondral disease (POD) of the metacarpo/metatarsophalangeal (Mc/MtPh) joints is common in Thoroughbred racehorses, but there is little information on predilection sites, associated pathologies and clinical signs. OBJECTIVES To describe the distribution of POD at post mortem examination and to examine the association of POD with other pathologies and clinical histories. METHODS The Mc/MtPh joints of 102 Thoroughbred racehorses were examined post mortem. Gross pathology of associated osteochondral elements, suspensory ligament and flexor tendons was recorded. Clinical data were extracted from computerised records. Relationships between all Mc/MtPh joint pathologies, clinical data and grade of POD in each condyle were determined using multilevel, ordinal logistic regression models. RESULTS Palmar/plantar osteochondral disease was recorded (grade 1-3 in at least one condyle) in 80.4% (95% confidence interval 71-88) of horses. The grade of POD was significantly higher in the forelimb, where the medial condyle had higher grades, than in the hindlimb, where the POD grade was higher in the lateral condyle. There was a significant positive relationship between POD grade and multiple other joint pathologies, whereas grades of linear fissures had a negative relationship with grade of POD. There was no relationship between grade of POD and tendon and suspensory ligament gross pathology, although horses with a history of tendon injury had significantly lower POD grades. Horses that had a clinical history of a Mc/MtPh joint problem had higher POD grades. In addition, horses that had been retired from racing for more than 2 months at the date of death had significantly lower POD grades. CONCLUSIONS AND POTENTIAL RELEVANCE Palmar/plantar osteochondral disease has specific predilection sites. Horses with a clinical history of Mc/MtPh-associated lameness had higher POD grades, whereas those with a history of superficial digital flexor tendon injury and retired horses had lower grades. The progression of POD and its ability to heal requires further evaluation.
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Affiliation(s)
- G L Pinchbeck
- Institute of Infection and Global Health, Faculty of Health and Life Sciences, University of Liverpool, UK
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Mason BJ, Riggs CM, Cogger N. Cohort study examining long-term respiratory health, career duration and racing performance in racehorses that undergo left-sided prosthetic laryngoplasty and ventriculocordectomy surgery for treatment of left-sided laryngeal hemiplegia. Equine Vet J 2012; 45:229-34. [PMID: 22812572 DOI: 10.1111/j.2042-3306.2012.00601.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
REASONS FOR PERFORMING STUDY The risk of respiratory conditions, such as inflammatory airway disease (IAD) and exercise-induced pulmonary haemorrhage (EIPH), are thought to be higher in racehorses that undergo prosthetic laryngoplasty with ventriculocordectomy (PLVC) surgery to treat left-sided laryngeal hemiplegia (LLH) than in racehorses with normal laryngeal function. However, this has not been investigated formally owing to the difficulty of obtaining reliable follow-up data. OBJECTIVES To determine the incidence of respiratory conditions (IAD and EIPH), duration of racing career, number of starts and number of starts for which stakes money was earned in racehorses that had undergone PLVC surgery to treat LLH, compared with racehorses that did not have LLH or undergo any laryngeal surgery. METHODS A retrospective cohort study design was used, with surgical, clinical and race data of Thoroughbred racehorses obtained from the time of importation until retirement. The surgical cohort consisted of racehorses that had undergone PLVC for LLH and met specific inclusion criteria. Every surgical case was matched, according to trainer, year of import into Hong Kong and pre-import international handicap rating, to 2 unexposed racehorses. RESULTS Respiratory conditions, such as excessive tracheal mucus and epistaxis due to severe EIPH, were significantly increased in the surgical cohort, compared with the matched unexposed cohort (P values <0.001 and <0.004, respectively). Racing career duration in the surgical cohort was significantly shorter than in the unexposed cohort, which was primarily due to retirement because of epistaxis. The number of race starts was fewer in the surgical than in the unexposed cohort after surgery/matching, but the number of starts for which stakes money was earned was not significantly different. CONCLUSIONS AND POTENTIAL RELEVANCE Owners and trainers should be advised that racehorses with LLH that undergo PLVC surgery are at an increased risk of respiratory conditions (IAD and severe EIPH), which is likely to shorten their racing career compared to racehorses with normal laryngeal function. Racing performance in terms of race starts was significantly less in racehorses that had undergone PLVC surgery; however, the number of starts for which stakes money was earned was similar to those racehorses that were unexposed.
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Affiliation(s)
- B J Mason
- Department of Veterinary Clinical Services, Hong Kong Jockey Club, Sha Tin Racecourse, Hong Kong, China.
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Boyde A, Riggs CM, Bushby AJ, McDermott B, Pinchbeck GL, Clegg PD. Cartilage damage involving extrusion of mineralisable matrix from the articular calcified cartilage and subchondral bone. Eur Cell Mater 2011; 21:470-8; discussion 478. [PMID: 21623571 DOI: 10.22203/ecm.v021a35] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Arthropathy of the distal articular surfaces of the third metacarpal (Mc3) and metatarsal (Mt3) bones in the Thoroughbred racehorse (Tb) is a natural model of repetitive overload arthrosis. We describe a novel pathology that affects the articular calcified cartilage (ACC) and subchondral bone (SCB) and which is associated with hyaline articular cartilage degeneration. Parasagittal slices cut from the palmar quadrant of the distal condyles of the left Mc3/Mt3 of 39 trained Tbs euthanized for welfare reasons were imaged by point projection microradiography, and backscattered electron (BSE) scanning electron microscopy (SEM), light microscopy, and confocal scanning light microscopy. Mechanical properties were studied by nanoindentation. Data on the horses' training and racing career were also collected. Highly mineralised projections were observed extending from cracks in the ACC mineralising front into the hyaline articular cartilage (HAC) up to two-thirds the thickness of the HAC, and were associated with focal HAC surface fibrillation directly overlying their site. Nanoindentation identified this extruded matrix to be stiffer than any other mineralised phase in the specimen by a factor of two. The presence of projections was associated with a higher cartilage Mankin histology score (P<0.02) and increased amounts of gross cartilage loss pathologically on the condyle (P<0.02). Presence of projections was not significantly associated with: total number of racing seasons, age of horse, amount of earnings, number of days in training, total distance galloped in career, or presence of wear lines.
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Affiliation(s)
- A Boyde
- Biophysics, Oral Growth and Development, The London School of Medicine and Dentistry, Queen Mary University of London, New Road, London E1 2AD, UK.
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Parkin TDH, Clegg PD, French NP, Proudman CJ, Riggs CM, Singer ER, Webbon PM, Morgan KL. Horse-level risk factors for fatal distal limb fracture in racing Thoroughbreds in the UK. Equine Vet J 2010; 36:513-9. [PMID: 15460076 DOI: 10.2746/0425164044877387] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
REASONS FOR PERFORMING STUDY Fractures below the level of the radius or tibia (distal limb fractures) are the most common cause of equine fatality on UK racecourses; however, little is known about their epidemiology or aetiology. Identification of risk factors could enable intervention strategies to be designed to reduce the number of fatalities. OBJECTIVES To identify horse-level risk factors for fatal distal limb fracture in Thoroughbreds on UK racecourses. METHODS A case-control study design was used. Fractures in case horses were confirmed by post mortem examination and 3 matched uninjured controls were selected from the race in which the case horse was running. One hundred and nine cases were included and information was collected about previous racing history, horse characteristics and training schedules. Conditional logistic regression was used to identify the relationship between a number of independent variables and the likelihood of fracture. RESULTS Horses doing no gallop work during training and those in their first year of racing were at significantly increased risk of fracture on the racecourse. Case horses were also more likely to have trained on a sand gallop, i.e. a gallop described by trainers as being primarily composed of sand. CONCLUSIONS Modifications to training schedules, specifically within the first year of racing, may have a large impact on the risk of fatal distal limb fracture on the racecourse. Horses should do some gallop work in training and our results suggest that the minimum distance galloped should be between 805-2012 m (4-10 furlongs)/week. POTENTIAL RELEVANCE The information from this study can be used to alter training schedules in an attempt to reduce the incidence of fatal distal limb fracture in Thoroughbred racehorses. Training should include some gallop work, and further studies, recording the exact level of work, will help to identify an optimum range of training speeds and distances which will reduce the liklihood of catastrophic fracture on the racecourse.
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Affiliation(s)
- T D H Parkin
- Department of Veterinary Clinical Science, University of Liverpool Veterinary Teaching Hospital, Leahurst, Neston, Wirral CH64 7TE, UK
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Parkin TDH, Clegg PD, French NP, Proudman CJ, Riggs CM, Singer ER, Webbon PM, Morgan KL. Risk factors for fatal lateral condylar fracture of the third metacarpus/metatarsus in UK racing. Equine Vet J 2010; 37:192-9. [PMID: 15892225 DOI: 10.2746/0425164054530641] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
REASONS FOR PERFORMING STUDY Lateral condylar fractures of the third metacarpus/metatarsus are the most common cause of equine fatality on UK racecourses. Identification of risk factors for such injuries and the subsequent implementation of intervention strategies could significantly reduce the total number of racecourse fatalities. OBJECTIVES To identify horse-, race- and course-level risk factors for fatal lateral condylar fracture in Thoroughbreds on UK racecourses. METHODS Case-control study designs were used. Case horses were defined as those that were subjected to euthanasia having sustained an irreparable lateral condylar fracture while racing at any of the 59 UK racecourses. Case races were defined as those in which one or more horses sustained a fatal lateral condylar fracture. Three controls for each case horse were selected at random from the race in which the case was running. Three controls for each case race were selected at random from all races of the same type held in the same year. Ninety-eight cases were included in the study. Conditional logistic regression was used to identify the relationship between a number of independent variables and the likelihood of fracture. RESULTS Horses doing no gallop work during training and those in their first year of racing were at significantly increased risk of fracture on the racecourse. Case horses were also more likely to have started racing as 3- or 4-year-olds. Fractures were found to be more likely in longer races with a larger number of runners, races in which professional jockeys were not permitted to ride and races in which the going was described as firm or hard. CONCLUSIONS AND POTENTIAL RELEVANCE Modifications to training schedules, specifically within the first year of racing, may have a large impact on the risk of fatal lateral condylar fracture on the racecourse. Horses should do some gallop work in training and our results suggest that the minimum distance galloped should be between 201 m (1 furlong) and 1609 m (8 furlongs) per week. The association with age at first race requires further investigation for flat and National Hunt racing separately. A reduction in the number of races taking place on very firm going could have an impact on the number of lateral condylar fractures.
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Affiliation(s)
- T D H Parkin
- Department of Veterinary Clinical Science, University of Liverpool Veterinary Teaching Hospital, Leahurst, Neston, Wirral CH64 7TE, UK
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Lam KH, Parkin TDH, Riggs CM, Morgan KL. Descriptive analysis of retirement of Thoroughbred racehorses due to tendon injuries at the Hong Kong Jockey Club (1992-2004). Equine Vet J 2007; 39:143-8. [PMID: 17378443 DOI: 10.2746/042516407x159132] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
REASONS FOR PERFORMING STUDY This study was part of a programme to optimise the longevity and maximise the health and welfare of the Thoroughbred racehorses in Hong Kong. Injuries to the superficial digital flexor (SDF) tendon are the most common veterinary reason for premature retirement in this population. OBJECTIVE To describe the frequency and pattern of retirements associated with SDF tendon injuries in Thoroughbred racehorses and to compare the characteristics of these horses with those that retired for other reasons. METHODS A retrospective analysis of retirement records documented in the Hong Kong Jockey Club clinical database between 1992 and 2004 was conducted. As this is complete census data, no statistical inference to the population is necessary. RESULTS The mean annual cumulative incidence of retirements due to tendon injury was 3.2% accounting for 14% of all retirements. The risk of tendon injury increased over the 12 year period from 23-4.2%. The racing career, number of starts and earnings of horses retired with tendon injuries were reduced by 25.6, 41.2 and 53.3%, respectively. Thirteen percent of these horses never raced in Hong Kong. A greater proportion of 3- and 4-year-olds and entire males were retired because of tendon injuries. Ninety-seven percent of injuries affected the forelimb, the right more frequently than the left. Only 19.7% of retired horses that had received ultrasound examination for SDF tendon injury retired for this reason. CONCLUSIONS This study provides population based data on the frequency, career and economic losses associated with tendon injury induced retirement. POTENTIAL RELEVANCE This descriptive study has provided a useful resource for further case-control studies to investigate risk factors for retirement from racing due to tendon injury. This is the first step toward the development of management tools to reduce the incidence of tendon injury related retirement in Hong Kong.
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Affiliation(s)
- K H Lam
- Department of Veterinary Regulation and International Liaison, Hong Kong Jockey Club, Sha Tin, N.T., Hong Kong
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Parkin TDH, Clegg PD, French NP, Proudman CJ, Riggs CM, Singer ER, Webbon PM, Morgan KL. Analysis of horse race videos to identify intra-race risk factors for fatal distal limb fracture. Prev Vet Med 2006; 74:44-55. [PMID: 16513194 DOI: 10.1016/j.prevetmed.2006.01.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The objective of this study was to identify risk factors, during racing, associated with imminent fatal distal limb fracture in Thoroughbreds. One hundred and nine cases of fatal distal limb fracture were identified from all 59 UK racecourses over a 2-year period (February 1999-January 2001). Three uninjured control horses were randomly selected from the same race as the case horse. Videos of races in which fractures occurred were viewed using a defined protocol. Fractures in flat races occurred at any time during the race, whereas 74% (45/61) of cases in national hunt type races occurred in the second half of races. More than 75% (79/103) of cases were spontaneous, i.e. there was no obvious external influence such as a fall at a fence or collision with another horse. Sixty-six percent (44/67) of horses, sustaining a forelimb fracture, fractured the forelimb they were using as lead leg at the time of fracture. When case and control horses were compared, horses that were: (a) making good progress through the race, (b) reluctant to start and (c) received encouragement in the final 10s before the time of fracture, were more likely to sustain a fracture.
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Affiliation(s)
- T D H Parkin
- Department of Veterinary Clinical Science, University of Liverpool Veterinary Teaching Hospital, Leahurst, Neston CH64 7TE, UK.
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Abstract
A horse in Hong Kong that had been vaccinated against Japanese encephalitis suffered a pyrexic episode that culminated in a hyperexcitable state and self-inflicted trauma. Japanese encephalitis was diagnosed on the basis of clinical, pathological and serological observations, and confirmed by the detection of genomic sequences of the virus in spinal cord tissue. Phylogenetic analyses of E gene and NS5-3'UTR sequences revealed divergent clustering of these segments with previously described genotypes, suggesting the possibility that the horse might have been infected with a recombinant between genotype I and genotype II viruses. Horses are considered to be dead-end hosts for the disease, but the occurrence of an infected horse in a population may have implications for the health status of the national herd. The effect that this case had on the horse industry in Hong Kong is discussed with specific reference to the movement of horses and the vaccination programme for Japanese encephalitis.
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Affiliation(s)
- K H K Lam
- Department of Veterinary Clinical Services, Hong Kong Jockey Club, Sha Tin Racecourse, Sha Tin, New Territories, Hong Kong
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16
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Parkin TDH, Clegg PD, French NP, Proudman CJ, Riggs CM, Singer ER, Webbon PM, Morgan KL. Catastrophic fracture of the lateral condyle of the third metacarpus/metatarsus in UK racehorses – fracture descriptions and pre-existing pathology. Vet J 2006; 171:157-65. [PMID: 16427592 DOI: 10.1016/j.tvjl.2004.10.009] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/02/2004] [Indexed: 11/22/2022]
Abstract
The characteristics of, and pre-existing pathology associated with 75 cases of fatal lateral condylar fracture sustained by Thoroughbreds while racing in the UK were described. Cases were identified from 220 cases of fatal distal limb fracture submitted as part of studies designed to identify risk factors for all fatal distal limb fractures. Fractures were most common in hurdle races and affected the right forelimb twice as often as the left forelimb. Fracture dimensions were similar to previous reports, however there was a much greater prevalence of articular and diaphyseal comminution and of concurrent fractures in the current report. Pre-existing pathology was particularly common in the medial and lateral parasagittal grooves of the distal articular surfaces of the third metacarpus/metatarsus. The degree of this pathology was not associated with horse age, length of career or number of career starts.
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Affiliation(s)
- T D H Parkin
- Department of Veterinary Clinical Science, University of Liverpool Veterinary Teaching Hospital, Leahurst, Neston CH64 7TE, UK.
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17
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Parkin TDH, Clegg PD, French NP, Proudman CJ, Riggs CM, Singer ER, Webbon PM, Morgan KL. Race- and course-level risk factors for fatal distal limb fracture in racing Thoroughbreds. Equine Vet J 2004; 36:521-6. [PMID: 15460077 DOI: 10.2746/0425164044877332] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
REASONS FOR PERFORMING STUDY Considerable variation in the rates of equine fatality at different racecourses draws attention to probable risk factors at the level of course or race that might be partly responsible. Distal limb fractures are the most common cause of equine fatality on UK racecourses and identification of risk factors for such injuries and subsequent implementation of intervention strategies could significantly reduce the total number of racecourse fatalities. OBJECTIVES To identify race- and course-level risk factors for fatal distal limb fracture in Thoroughbreds on UK racecourses. METHODS A case-control study design was used. Case races were defined as those in which one or more horses sustained fatal fracture of the distal limb. Controls were selected in 2 different ways. Firstly, 3 races in which no fracture occurred were selected from all races of the same type held within 5 days of the case race (Analysis 1). Secondly, 3 control races were selected for each case race from all races of the same type held in the same year (Analysis 2). One hundred and nine cases were included in the study. Information about the race and the racecourses was collected from Computer Raceform. Conditional logistic regression was used to identify the relationship between a number of independent variables and the likelihood of fracture in a race. RESULTS Longer races with a larger number of runners were more likely to contain a fracture. Firmer going and fewer days since the last race on the same course were associated with an increased risk of fracture. The going at the course at the previous race meeting was also associated with the likelihood of fracture. CONCLUSIONS Modifications to the going on the day of a race and greater emphasis on ground maintenance between race meetings may have an impact on the risk of fatal distal limb fracture during racing. POTENTIAL RELEVANCE Modification of risk factors such as the going and number of days since the last race meeting could reduce the number of equine fatalities on UK racecourses. The condition of the racecourse may be an important risk factor and future research should focus on the identification of course maintenance techniques that produce the safest possible racing surfaces.
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Affiliation(s)
- T D H Parkin
- Department of Veterinary Clinical Science, University of Liverpool Veterinary Teaching Hospital, Leahurst, Neston, Wirral CH64 7TE, UK
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18
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Parkin TDH, Clegg PD, French NP, Proudman CJ, Riggs CM, Singer ER, Webbon PM, Morgan KL. Risk of fatal distal limb fractures among thoroughbreds involved in the five tpes of racing in the United Kingdom. Vet Rec 2004; 154:493-7. [PMID: 15130054 DOI: 10.1136/vr.154.16.493] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The risk of fatal distal limb fractures in thoroughbreds racing in the UK was calculated and shown to vary considerably between the different types of race. Flat turf racing was associated with the lowest risk (0.4 per 1000 starts) and national hunt flat racing was associated with the highest risk (2.2 per 1000 starts). The types of fracture were classified by detailed radiographic and postmortem examinations of all the cases recorded over two years, and the distribution of the different types of fracture in the five main types of racing was examined. Overall, lateral condylar fractures of the third metacarpus were the most common, and they were also the most common in national hunt-type races (hurdle, steeplechase and national hunt flat races). In all-weather flat racing biaxial proximal sesamoid fractures were most common, and in turf flat racing fractures of the first phalanx were most common. The risk of fractures of more than one bone was greater in national hunt-type races.
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Affiliation(s)
- T D H Parkin
- Department of Veterinary Clinical Science, Faculty of Veterinary Science, University of Liverpool, Leahurst, Chester High Road, Neston, South Wirral CH64 7TE
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Affiliation(s)
- C M Riggs
- Oakey Veterinary Hospital, PO Box 2, Oakey, Queensland 4401, Australia
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20
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Abstract
Fractures are a common cause of loss among Thoroughbred racehorses. A large proportion of these injuries occurs in the absence of a specific traumatic event and show typical characteristics of stress fractures. The fractures show a high degree of consistency in their morphology; they frequently share the same locations as incomplete cracks and they are often associated with pre-existing pathology (periosteal and endosteal new bone formation and intracortical remodelling). Bone is able to adapt to changes in its mechanical environment. Studies of the Thoroughbred racehorse show modification of the geometric properties of the third metacarpal bone in response to training. These modifications are associated with reduced bone strains. Intense training before the adaptive response is completed and bone strain reduced increases the risk of fatigue damage. Fatigue of bone is associated with progressive microdamage, which is important in the pathogenesis of stress fractures. However, the biological repair mechanism of bone (remodelling) is also instrumental in the development of stress fractures. Horses exercised before bone repair is complete are likely to be at significantly greater risk of sustaining a catastrophic stress fracture. A number of key questions regarding the importance of microdamage, remodelling and training schedules in the prevention of stress fractures are addressed in this review.
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Affiliation(s)
- C M Riggs
- Oakey Veterinary Hospital, Oakey, Queensland, 4401, Australia.
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21
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Abstract
The present study addressed the question of whether training induces changes in bone density in the younger racehorse in regions relevant to the genesis of the common sagittal condylar fracture pattern and, if so, the nature of such alteration. Third metacarpal bones (McIII) were obtained from 12 experimental Thoroughbred, unbroken fillies, age 18.1-21.0 months at entry to the study. Six (Group E) undertook 19 weeks of progressive high intensity exercise on a high-speed treadmill at 3% incline. Six (Group C) walked 40 min each day. Clinical bone density was studied by Computed Tomography (CT) of the right McIII. 1:1 aspects of bone density were studied by digital radiography of slices and microscopic aspects by backscattered electron (BSE) imaging. There was a distinct pattern of regional variation in bone density throughout the distal condyles of McIII. Bone density was greater in specimens from Group E than those from Group C by CT, by radiographic density and by bone volume fraction as determined from backscattered electron images: the latter also showed that the most important change was in the increased amount of bone deposited within antecedent marrow space in cancellous tissue in Group E compared with Group C, with more extensive regional involvement in the highly loaded (distopalmar) aspects of the medial and lateral condyles. However, this space-filling bone fraction had a lower degree of mineralisation than the prior bone tissue, showing that CT and radiography underestimate the resultant increased bone volume fraction. Stress fractures of the distal condyles of the McIII are common in Thoroughbred racehorses. We propose that excess stiffening within the condyles due to extensive new bone formation may lead to concentration of strain at the condylar grooves and incipient cracking through calcified cartilage and into the subchondral bone.
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Affiliation(s)
- C M Riggs
- Department of Veterinary Clinical Studies and Animal Husbandry, University of Liverpool, Neston, South Wirral, UK
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22
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Abstract
This study examined material from Thoroughbred horses, the majority of which had been in race training, for evidence of pathology in the third metacarpal (McIII) and third metatarsal (MtIII) bones which might be related to the occurrence of distal condylar fractures. Whole bone samples were studied and documented by macrophotography prior to macroradiography and computed tomographic (CT) imaging. Microradiographs were made from 100 microm thick mediolateral sections cut perpendicular to the dorsal and palmar/plantar articular surfaces of distal condylar regions of McIII and MtIII. Blocks were prepared for morphological imaging using the backscattered electron mode of scanning electron microscopy (BSE SEM). Linear defects in mineralised articular cartilage and subchondral bone were found in the palmar/plantar aspects of the condylar grooves adjacent to the sagittal ridge. These were closely related to the pattern of densification of the subchondral bone and were associated with intense focal remodelling of the immediately adjacent and subjacent bone. Parasagittal fractures of the condyles originated in similar defects. A unifying hypothesis for the aetiopathogenesis of these fractures is presented.
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Affiliation(s)
- C M Riggs
- Department of Veterinary Clinical Science, University of Liverpool, Neston, UK
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23
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Abstract
This study examined the three-dimensional (3D) microarchitecture of regions of the equine third metacarpal bone (McIII) commonly involved in distal condylar fractures. Limbs were obtained from Thoroughbred horses (neonates to age 24 years) destroyed for inoperable fractures and a variety of other conditions. Beams, blocks and sections were cut in the principal axes, some embedded in PMMA and others examined unembedded. Several methods were used to study the 3D structure, including conventional and confocal optical microscopy, scanning electron microscopy (SEM) and radiography. The mineralised articular cartilage tends to cleave in the sagittal plane. Proximal to the subchondral bone, the main trabeculae are robust plates running in the sagittal direction with less significant mediolateral connections. Small blood vessel canals lie inside the sagittal plates. This structure gives maximum strength and protection in the sagittal plane in which the bone rotates, but offers minimal resistance to fracture propagation in this plane. The anatomical course of the common distal condylar fractures of the third metacarpal bones can be explained by underlying anisotropic structural features of the mineralised tissues.
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Affiliation(s)
- A Boyde
- Department of Anatomy and Developmental Biology, University College London, UK
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24
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Abstract
Fractures are the cause of considerable morbidity and mortality among Thoroughbred racehorses. A significant proportion of these injuries occur in the absence of any particular traumatic incident. Evidence of prefracture pathology interpreted as fatigue damage has been identified in some such cases, but the aetiology of many of these so-called 'spontaneous' fractures remains obscure. Parasagittal fractures of the third metacarpal (McIII) and third metatarsal (MtIII) bones are one of the more common fractures to affect Thoroughbred racehorses. The configuration of each of these fracture types is highly consistent, suggesting a predisposition of the bones to these injuries. Several theories have been proposed to explain the aetiopathogenesis of these fractures although none has so far stood up to critical examination. The current paper reviews the literature relating to parasagittal fractures of McIII and MtIII.
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Affiliation(s)
- C M Riggs
- Department of Veterinary Clinical Science and Animal Husbandry, University of Liverpool, Neston, UK
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25
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Abstract
This study examined 3-dimensional (3D) distribution of sectors with contrasting density in the equine third metacarpal (McIII) and third metatarsal (MtIII) bones with a view to explaining the aetiology of distal condylar fractures. Macroradiography and computed tomographic (CT) imaging were used in the nondestructive study of bones obtained from horses, most of which were Thoroughbreds in race training. Distal condylar regions of McIII and MtIII were also studied in microradiographs of 100 microm thick mediolateral sections cut perpendicular to the dorsal and palmar/plantar articular surfaces. Qualitative and quantitative results from all methods used (radiography, CT and microradiographic stereology) demonstrated a densification (sclerosis) of subchondral bone located in the palmar/plantar regions of the medial and lateral condyles of both McIII and MtIII. Substantial density gradients between the denser condyles and the subchondral bone of the sagittal groove were shown to equate with anatomical differences in loading intensity during locomotion. It is hypothesised that such differences in bone density results in stress concentration at the palmar/plantar aspect of the condylar grooves, which may predispose to fracture.
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Affiliation(s)
- C M Riggs
- Department of Veterinary Clinical Science and Animal Husbandry, University of Liverpool, Neston, UK
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26
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Clegg PD, Burke RM, Coughlan AR, Riggs CM, Carter SD. Characterisation of equine matrix metalloproteinase 2 and 9; and identification of the cellular sources of these enzymes in joints. Equine Vet J 1997; 29:335-42. [PMID: 9306058 DOI: 10.1111/j.2042-3306.1997.tb03136.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The cellular production by resident articular cells and infiltrating inflammatory cells of the gelatinase matrix metalloproteinases (MMP) was investigated by tissue culture methods and analysis of cell supernatants by gelatin zymography. Peripheral blood neutrophils in short term culture produced MMP-9, as did peripheral blood monocytes in culture. Isolated articular chondrocytes in monolayer culture produced both MMP-2 and MMP-9, although articular cartilage maintained as explant culture produced MMP-2 alone. Synovial fibroblasts grown in monolayer culture produced MMP-2 alone, although synovial membrane in explant culture produced both MMP-2 and the active form of MMP-2. Lysis of blood polymorph neutrophils produced large quantities of MMP-9, but lysis of blood monocytes, synovial fibroblasts and articular chondrocytes produced little enzyme indicating that, unlike the other cell types, polymorph neutrophils store MMPs intracellularly. Equine MMP-2 was purified from synovial fibroblast cell culture supernatant, and equine MMP-9 from polymorph neutrophil cell culture supernatant, by gelatin-sepharose affinity chromatography. The 2 enzymes were identified from their molecular weights and by their respective N-terminal amino acid sequences which showed homology with the enzymes from other species. The demonstration that invasive cells and resident articular cells can produce enzymes which are capable of digestion of certain component molecules of the articular cartilage matrix, shows that therapeutic targeting of these enzymes could be a valid proposition in the prevention of cartilage destruction in osteoarthritis.
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Affiliation(s)
- P D Clegg
- Department of Veterinary Clinical Science and Animal Husbandry, University Veterinary Teaching Hospital, University of Liverpool, Leahurst, UK
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27
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28
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Abstract
Matrix metalloproteinases (MMPs) may be important in the destruction of cartilage seen in equine osteoarthritis and may be detectable in synovial fluid. Synovial fluids were obtained from normal equine joints and from joints of horses with aseptic and septic joint diseases. The total MMP gelatinase enzyme activities were measured by gelatin zymography and image analysis of the gels. The bioactivity of gelatinase in synovial fluid was determined by a gelatin degradation ELISA. Potential MMP-2 & MMP-9 monomer enzyme activities were significantly elevated in both septic and aseptic joint disease synovial fluids in comparison to fluids from normal joints. The dimer form of MMP-9 enzyme activity was significantly elevated in fluids from septic joint disease cases in comparison to fluids form normal joints, but not fluids from horses with aseptic joint diseases. MMP-9 monomer and dimer levels in synovial fluids correlated with the synovial fluid white blood cell count. Using the gelatin degradation ELISA to measure net active gelatinases, significant increases in gelatinase bioactivities were seen in synovial fluids from both aseptic and septic joint disease cases. The enzymes in equine joint diseases were present in a bioactive form, in that they were present in the activated form and present in excess of inhibitors, and could therefore be important in the degradation of articular cartilage in joint disease.
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Affiliation(s)
- P D Clegg
- Department of Veterinary Clinical Science and Animal Husbandry, University Veterinary Teaching Hospital, University of Liverpool, Leahurst, UK
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29
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Pilsworth RC, Riggs CM. The motto of necessity: imaging modalities for orthopaedic prognosis. Equine Vet J 1996; 28:341-3. [PMID: 8894529 DOI: 10.1111/j.2042-3306.1996.tb03102.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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30
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DeCamp CE, Riggs CM, Olivier NB, Hauptman JG, Hottinger HA, Soutas-Little RW. Kinematic evaluation of gait in dogs with cranial cruciate ligament rupture. Am J Vet Res 1996; 57:120-6. [PMID: 8720250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVE Noninvasive, computer-assisted, three-dimensional kinematic gait analysis was used to describe lameness in a chronic model of cranial cruciate ligament rupture (CCLR) in dogs. DESIGN Hind limb lameness was evaluated prior to and at 1, 3, and 6 months after transection of the cranial cruciate ligament. ANIMALS Seven clinically normal large dogs. PROCEDURE Dynamic flexion and extension angles and angular velocities were calculated for the coxofemoral, femorotibial, and tarsal joints. Distance and temporal variables were determined. Essential Fourier coefficients were used to develop mean flexion extension curves for all joints and to compare changes in movement that developed with CCLR over time. RESULTS Each joint had a characteristics pattern of flexion and extension movement that changed with CCLR. The femorotibial joint angle was more flexed throughout stance and early swing phase of stride and failed to extend in late stance. Angular velocity of the femorotibial joint was damped throughout stance phase, with extension velocity almost negligible. The coxofemoral and tarsal joint angles, in contrast to the femorotibial joint angle, were extended more during stance phase. These changes were documented as differences noted in the essential Fourier coefficients. Stride length and frequency also varied significantly after CCLR. CONCLUSIONS Cranial cruciate ligament rupture affects movement of the coxofemoral and tarsal joints, as well as the femorotibial joint, in gait. A pattern of joint movement may be discerned in which the coxofemoral and tarsal joints compensate for the dysfunction of the femorotibial joint. CLINICAL RELEVANCE Methods were developed that will improve objective evaluation of CCLR and its treatment in dogs.
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Affiliation(s)
- C E DeCamp
- Department of Small Animal Clinical Sciences, Michigan State University, East Lansing 48824-1314, USA
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31
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Walker RD, Walshaw R, Riggs CM, Mosser T. Recovery of two mycoplasma species from abscesses in a cat following bite wounds from a dog. J Vet Diagn Invest 1995; 7:154-6. [PMID: 7779953 DOI: 10.1177/104063879500700126] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Affiliation(s)
- R D Walker
- Department of Microbiology, College of Veterinary Medicine, Michigan State University, East Lansing 48824, USA
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32
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Anderson LM, Logsdon D, Ruskie S, Fox SD, Issaq HJ, Kovatch RM, Riggs CM. Promotion by polychlorinated biphenyls of lung and liver tumors in mice. Carcinogenesis 1994; 15:2245-8. [PMID: 7955061 DOI: 10.1093/carcin/15.10.2245] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Polychlorinated biphenyls (PCB), which are tumor promoters, have been found in human tissues for decades. Their contribution to cancer risk may only now start to appear, due to long human cancer latency and the nature of tumor promotion. Epidemiological associations have been seen between PCB exposure or tissue content and cancer at several sites. In rodents, tumor promotion by PCBs has been little studied in tissues other than liver. Previously, in an experiment modeling infant carcinogen exposure following PCBs received in milk, lung and liver tumors, initiated neonatally in mice by the environmental nitrosamine N-nitrosodimethylamine (NDMA), were promoted by later treatment with Aroclor 1254. The present study was undertaken to confirm and characterize the effects of Aroclor 1254 on tumor number, latency, size and malignancy. Male Swiss mice were given NDMA on postnatal day 4 and Aroclor 1254 (250 mg/kg) on day 8, and killed at intervals. Eight PCB congeners were quantified in the carcasses. Incidences of mice with NDMA-initiated lung tumors at 28 weeks of age were increased 2.5-fold by PCBs. Multiplicities of lung tumors were enhanced four-fold by PCBs at 28 and 52 weeks. By 72 weeks tumor numbers were similar in the NDMA-only and NDMA-PCB groups. Liver tumors first occurred in significant numbers at 52 weeks and only in mice receiving both NDMA and PCBs. As for the lung, at 72 weeks the incidence was high in both the NDMA-only and NDMA-PCB groups. Sizes of tumors and liver carcinoma incidence were not altered by PCB treatment. Carcass analysis revealed a significant positive association between lung tumor numbers at 28 weeks and relative percentage of 2,2',4,4',5-pentachlorobiphenyl, with no other correlations. The results confirm that PCBs promote lung as well as liver tumors, by triggering the early appearance of latent initiated tumors otherwise presenting in old age.
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Affiliation(s)
- L M Anderson
- Laboratory of Comparative Carcinogenesis, National Cancer Institute, Frederick Cancer Research and Development Center, Ft Detrick, MD 21702-1201
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Riggs CM, DeCamp CE, Soutas-Little RW, Braden TD, Richter MA. Effects of subject velocity on force plate-measured ground reaction forces in healthy greyhounds at the trot. Am J Vet Res 1993; 54:1523-6. [PMID: 8239144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Force plate gait analysis was used to study the effects of subject velocity on ground reaction forces. Seven adult Greyhounds were trotted at 3 distinct velocities: 1.5 to 1.8 m/s, 2.1 to 2.4 m/s, and 2.7 to 3.0 m/s. Forelimb and hind limb peak vertical forces increased with increase in velocity (P < 0.05). Forelimb and hind limb vertical impulses decreased as velocity increased (P < 0.05). Significant variations were not observed for craniocaudal or mediolateral peak forces or impulses. It was concluded that velocity significantly (P < 0.05) influenced ground reaction forces and impulses, and must be controlled in experimental design.
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Affiliation(s)
- C M Riggs
- College of Veterinary Medicine, Michigan State University, East Lansing 48824
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Riggs CM, Lanyon LE, Boyde A. Functional associations between collagen fibre orientation and locomotor strain direction in cortical bone of the equine radius. Anat Embryol (Berl) 1993; 187:231-8. [PMID: 8470823 DOI: 10.1007/bf00195760] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A novel technique for determining the collagen fibre orientation pattern of cross-sections of cortical bone was used to study mid-diaphyseal sections from the equine radius. Several in vivo strain gauge studies have demonstrated that this bone is loaded in bending during locomotion in such a way that the cranial cortex is consistently subjected to longitudinal tensile strains and the caudal cortex to longitudinal compressive strains. Twenty-three radii from 17 horses were studied. All the bones obtained from adult horses exhibited a consistent pattern of collagen fibre orientation across the cortex. The cranial cortex, subjected to intermittent tension, and the lateral and medial cortices, through which the neutral axis passes, contained predominantly longitudinally oriented collagen fibres. The caudal cortex, subjected to longitudinal compression during life, contained predominantly oblique/transverse collagen. This pattern was less evident in bones from foals. Microscopic analysis of the bones studied showed that primary lamellar bone was composed of predominantly longitudinal collagen fibres, irrespective of cortex. However, there was a strong relationship between cortical location and fibre orientation within remodelled bone. Secondary osteons which formed in the caudal (compressive) cortex contained predominantly oblique/transverse collagen, while those which formed elsewhere contained longitudinal collagen. This observation explained the developmental appearance of the characteristic macroscopic pattern of collagen fibre orientation across the whole cortex in the adult. These findings provide evidence for the existence of a relationship between the mechanical function of a bone with its architecture, and now demonstrate that it extends to the molecular level.
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Affiliation(s)
- C M Riggs
- Department of Large Animal Clinical Science, Royal Veterinary College, University of London, UK
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35
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Riggs CM, Vaughan LC, Evans GP, Lanyon LE, Boyde A. Mechanical implications of collagen fibre orientation in cortical bone of the equine radius. Anat Embryol (Berl) 1993; 187:239-48. [PMID: 8470824 DOI: 10.1007/bf00195761] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Mechanical test specimens were prepared from the cranial and caudal cortices of radii from eight horses. These were subjected to destructive tests in either tension or compression. The ultimate stress, elastic modulus and energy absorbed to failure were calculated in either mode of loading. Analysis was performed on the specimens following mechanical testing to determine their density, mineral content, mineral density distribution and histological type. A novel technique was applied to sections from each specimen to quantify the predominant collagen fibre orientation of the bone near the plane of fracture. The collagen map for each bone studied was in agreement with the previously observed pattern of longitudinal orientation in the cranial cortex and more oblique to transverse collagen in the caudal cortex. Bone from the cranial cortex had a significantly higher ultimate tensile stress (UTS) than that from the caudal cortex (160 MPa vs 104 MPa; P < 0.001) though this trend was reversed in compression, the caudal cortex becoming relatively stronger (185 MPa vs 217 MPa; P < 0.01). Bone from the cranial cortex was significantly stiffer than that from the caudal cortex both in tension (22 GPa vs 15 GPa; P < 0.001) and compression (19 GPa vs 15 GPa; P < 0.01). Of all the histo-compositional variables studied, collagen fibre orientation was most closely correlated with mechanical properties, accounting for 71% of variation in ultimate tensile stress and 58% of variation in the elastic modulus. Mineral density and porosity were the only other variables to show any significant correlation with either UTS or elastic modulus. The variations in mechanical properties around the equine radius, which occur in close association with the different collagen fibre orientations, provide maximal safety factors in terms of ultimate stress, yet contribute to greater bending of the bone as it is loaded during locomotion, and thus lower safety factors through the higher strains this engenders.
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Affiliation(s)
- C M Riggs
- Department of Large Animal Clinical Science, Royal Veterinary College, North Mymms, Herts, UK
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Abstract
The velocity of ultrasound waves through bone has been used widely as a non-invasive method for assessing bone quality. Accurate measurement of velocity depends on accurate assessment of the distance travelled by the sound wave. It has been argued that the sonic pathway is deflected around the marrow cavity and so does not follow a straight line through the bone; therefore, correction factors have been developed to account for the extra distance travelled. This hypothesis was examined in vitro using sections from the equine third metacarpal bone. Two 1 MHz transducers used with the transmitting transducer energized by a 600 V electrical spike generator produced a 0.1 microsecond pulse width and the received signal was recorded on a delayed time-base oscilloscope, from which the velocity was calculated. Two distinct peaks were apparent in the received signal, corresponding to a direct cortical transmission wave and a direct medullary transmission wave. This observation was confirmed quantitatively using models of the third metacarpal made from homogeneous materials that allow accurate determination of the transit times of each component of the signal. Perspex was used to mimic cortical bone, with water as the mimic for the contents of the medullary canal; these materials were chosen because they have transmission velocities similar to the materials they were mimicking. The results confirmed that the pathway went straight through the bone with a time lag in the medullary wave due to the slower transmission velocity of the marrow. To ensure that the cortical wave is always received, transducers larger than the medullary width should always be used.
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Affiliation(s)
- C M Langton
- Department of Applied Physics, Sheffield City Polytechnic, UK
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Carando S, Portigliatti-Barbos M, Ascenzi A, Riggs CM, Boyde A. Macroscopic shape of, and lamellar distribution within, the upper limb shafts, allowing inferences about mechanical properties. Bone 1991; 12:265-9. [PMID: 1793677 DOI: 10.1016/8756-3282(91)90074-s] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Collagen orientation maps were determined for the long bones of the upper forelimb (humerus, ulna, radius) using previously described techniques. All three bones had characteristic, non-random patterns of collagen fibre orientation. In the humerus, transverse collagen predominated in the medial and posterior cortices proximally and in the anterior and posterior cortices at the mid diaphysis. In the distal radius, the medial and anterior cortices contained mostly transverse collagen. In the proximal ulna, transverse collagen was found in the anterior and anterolateral cortices. These findings may be correlated to the distribution of bending forces that may be operative in these bones.
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Affiliation(s)
- S Carando
- Orthopaedic Department, University of Turin, Italy
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Langton CM, Ali AV, Riggs CM, Evans GP, Bonfield W. A contact method for the assessment of ultrasonic velocity and broadband attenuation in cortical and cancellous bone. Clin Phys Physiol Meas 1990; 11:243-9. [PMID: 2245589 DOI: 10.1088/0143-0815/11/3/007] [Citation(s) in RCA: 96] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A portable system using a direct contact for the measurement of ultrasonic velocity and broadband attenuation in bone is described (contact ultrasonic bone analyser, CUBA). Soft-tissue compensation is performed using an ultrasonic pulse-echo technique. CUBA has been successfully validated using reference materials, the precision of velocity and broadband attenuation measurements being typically 0.2% and 0.5% respectively. The clinical reproducibility has been assessed on the equine third metacarpal bone. The reproducibility of velocity measurement is typically 0.5% for cortical bone and 1% for cancellous bone. For broadband attenuation the reproducibility is typically 7% for cortical bone and 6% for cancellous bone. The lower reproducibility of the attenuation data is attributed to the high sensitivity to variations in the material properties of bone with small changes in transducer positioning. Coupling difficulties through an intact equine coat have been overcome and the system may now be assessed in the clinical environment, in both human and animal populations.
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Affiliation(s)
- C M Langton
- Applied Physics Department, Sheffield City Polytechnic, UK
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Abstract
We describe and validate a simple method for the study of the proportion of collagen fibers (and apatite crystals) in a bone slice parallel with the plane of section. Viewed between crossed circular polarizers, all bone areas with collagen lying more nearly in the plane of section (i.e., transverse [TS] collagen) appear bright whatever its direction in this plane; longitudinal [LS] collagen appears dark, but not as dark as the background. The degree of brightness increases with section thickness, which must therefore be standardized--we chose 100 microns plane parallel sections. We transferred the circularly polarized light [CPL] image via a CCD TV camera to an image analyzing computer. Color-coded maps of the CPL image were used to compare regions within and between sections. The new analytical procedure makes more detailed studies of the fine-structural orientation in compact bone possible, but does this have any significance? To answer this question, a bone in which the in vivo strain pattern had been clearly documented was chosen for particular study. Transverse mid-diaphyseal sections of the equine radius showed a distribution of CPL bright areas which correlated closely with previously reported strain patterns.
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Affiliation(s)
- A Boyde
- Dept. of Anatomy and Developmental Biology, University College London, U.K
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Abstract
Experiments were performed to reinvestigate the importance of mammary engorgement for activation of the milk-ejection reflex in the rat. Reflex milk ejection (measured by intramammary pressure recordings during a 2-h suckling test under anaesthesia) was compared in rats with engorged mammary glands (15-h separation from the pups, followed by sham-removal of milk) and in rats with drained mammary glands (15-h separation, followed by milk removal using a foster litter and exogenous oxytocin). In experiment 1, multiple small (2 mu.) doses of oxytocin were used for milk removal: these were effective in emptying the mammary glands and caused no subsequent impairment or change in sensitivity of the mammary response to oxytocin. Using this draining procedure, no significant differences were observed in either the number or relative amplitude of the milk ejections, or the occurrence of pup stretch reactions between engorged and drained rats. Similar results were seen in experiment 2, where an identical draining protocol was used, but the rats were pretreated with propranolol before the suckling test. In experiment 3, large (250 mu.) oxytocin doses were used for milk removal, as in previous studies. Again mammary draining had no effect on milk ejection in a subsequent suckling test (with propranolol pretreatment). However, the number of stretch reactions shown by the pups was significantly (P less than 0.001) reduced from 8.6 +/- 1.4/2 h to 1.9 +/- 0.6/2 h. This effect probably related to long-term impairment of the oxytocin response of the mammary glands following the draining procedure, and could not be attributed to the draining per se.(ABSTRACT TRUNCATED AT 250 WORDS)
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