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P. Muir - One of the best experts on this subject based on the ideXlab platform.
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fractographic examination of racing Greyhound central navicular tarsal bone failure surfaces using scanning electron microscopy
Calcified Tissue International, 2000Co-Authors: J L Tomlin, Timothy J. Lawes, Gordon W. Blunn, Allen E. Goodship, P. MuirAbstract:The Greyhound is a fatigue fracture model of a short distance running athlete. Greyhounds have a high incidence of central (navicular) tarsal bone (CTB) fractures, which are not associated with overt trauma. We wished to determine whether these fractures occur because of accumulation of fatigue microdamage. We hypothesized that bone from racing dogs would show site-specific microdamage accumulation, causing predisposition to structural failure. We performed a fractographic examination of failure surfaces from fractured bones using scanning electron microscopy and assessed microcracking observed at the failure surface using a visual analog scale. Branching arrays of microcracks were seen in failure surfaces of CTB and adjacent tarsal bones, suggestive of compressive fatigue failure. Branching arrays of microcracks were particularly prevalent in remodeled trabecular bone that had become compact. CTB fractures showed increased microdamage when compared with other in vivo fractures (adjacent tarsal bone and long bone fractures), and ex vivo tarsal fractures induced by monotonic loading (P < 0.02). It was concluded that Greyhound racing and training often results in CTB structural failure, because of accumulation and coalescence of branching arrays of fatigue microcracks, the formation of which appears to be predisposed to adapted bone.
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Asymmetric adaptive modeling of central tarsal bones in racing Greyhounds.
Bone, 2000Co-Authors: Kenneth A. Johnson, P. Muir, R.g Nicoll, James K. RoushAbstract:Fatigue fracture of the cuboidal bones of the foot, especially the navicular tarsal bone, is common in athletes and dancers. The racing Greyhound is a naturally occurring animal model of this injury because both microcracking and complete fracture occur in the right central (navicular) tarsal bone (CTB). The right limb is on the outside when racing in a counter-clockwise direction on circular tracks, and is subjected to asymmetric cyclic compressive loading. We wished to study in more detail adaptive modeling in the right CTB in racing Greyhounds. We hypothesized that cyclic asymmetric loading of a cuboidal bone induced by racing on a circular track would induce site-specific bone adaptation. We also hypothesized that such an adaptive response would be attenuated in Greyhounds that were retired from racing and no longer subjected to cyclic asymmetric loading. Central tarsal bones from racing Greyhounds (racing group, n = 6) and retired Greyhounds being used for breeding (nonracing group, n = 4) were examined using quantitative computed tomography (CT). Bone mineral density (BMD) was determined in a 3-mm diameter region-of-interest (ROI) in six contiguous 1-mm-thick sagittal CT slices of each CTB. Bones were subsequently examined histomorphometrically and percentage bone area (B.Ar./T.Ar., %) was determined in 10 ROI from dorsal to plantar in a transverse plane, mid-way between the proximal and distal articular surfaces. The BMD of the right CTB was greater than the left in all Greyhounds (p 0.8; power = 80% at Δ = 48%). It was concluded that Greyhounds racing on circular tracks develop site-specific bone adaptation with compaction of trabecular bone and increase in BMD in the right CTB in particular, the most common site for fatigue fracture. Our data also suggested that partial reversal of this adaptive process occurred in retired, nonracing Greyhounds, after cessation of asymmetric cyclic loading at racing speed. Racing Greyhounds provide a model in which to study fatigue fracture and adaptation of cuboidal foot bones subjected to cyclic loading.
J L Tomlin - One of the best experts on this subject based on the ideXlab platform.
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fractographic examination of racing Greyhound central navicular tarsal bone failure surfaces using scanning electron microscopy
Calcified Tissue International, 2000Co-Authors: J L Tomlin, Timothy J. Lawes, Gordon W. Blunn, Allen E. Goodship, P. MuirAbstract:The Greyhound is a fatigue fracture model of a short distance running athlete. Greyhounds have a high incidence of central (navicular) tarsal bone (CTB) fractures, which are not associated with overt trauma. We wished to determine whether these fractures occur because of accumulation of fatigue microdamage. We hypothesized that bone from racing dogs would show site-specific microdamage accumulation, causing predisposition to structural failure. We performed a fractographic examination of failure surfaces from fractured bones using scanning electron microscopy and assessed microcracking observed at the failure surface using a visual analog scale. Branching arrays of microcracks were seen in failure surfaces of CTB and adjacent tarsal bones, suggestive of compressive fatigue failure. Branching arrays of microcracks were particularly prevalent in remodeled trabecular bone that had become compact. CTB fractures showed increased microdamage when compared with other in vivo fractures (adjacent tarsal bone and long bone fractures), and ex vivo tarsal fractures induced by monotonic loading (P < 0.02). It was concluded that Greyhound racing and training often results in CTB structural failure, because of accumulation and coalescence of branching arrays of fatigue microcracks, the formation of which appears to be predisposed to adapted bone.
C. Guillermo Couto - One of the best experts on this subject based on the ideXlab platform.
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Blood gas analysis and cooximetry in retired racing Greyhounds.
Journal of Veterinary Emergency and Critical Care, 2011Co-Authors: Sara Zaldívar-lópez, L.m. Marín, C. Guillermo Couto, M.c. Iazbik, Maxey L. Wellman, Hope K. Chisnell, Nicole Westendorf-stingle, Edward S. Cooper, William W. MuirAbstract:Objective – The purposes of this study were to evaluate the oxygen affinity of hemoglobin (Hb) in healthy retired racing Greyhounds via cooximetry, and to establish reference intervals for blood gases and cooximetry in this breed. Design – Prospective clinical study. Setting – University Teaching Hospital. Animals – Fifty-seven Greyhounds and 30 non-Greyhound dogs. Interventions – Venous blood samples were collected from the jugular vein and placed into heparinized tubes. The samples were analyzed within 30 minutes of collection using a blood gas analyzer equipped with a cooximeter. Measurements and Main Results – Greyhounds had significantly higher pH, PO2, oxygen saturation, oxyhemoglobin, total Hb, oxygen content, and oxygen capacity and significantly lower deoxyhemoglobin and P50 when compared with non-Greyhound dogs. Conclusion – These findings support the fact that this breed is able to carry a higher concentration of total oxygen in the blood. As reported previously, this breed also has lower P50 and, therefore, high oxygen affinity. In light of recent findings suggesting that in certain tissues a high affinity for oxygen is beneficial, this adaptation may be of benefit during strenuous exercise.
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Serum concentrations of IgG, IgA, and IgM in retired racing Greyhound dogs.
Veterinary Clinical Pathology, 2010Co-Authors: M. Clemente, L.m. Marín, M. Cristina Iazbik, C. Guillermo CoutoAbstract:Background: Greyhound dogs have significant physiologic, hematologic, and biochemical differences when compared with other breeds, including significantly lower serum globulin concentration owing to decreases in the α- and β-globulin fractions. The specific proteins that account for differences in globulin concentrations are not known, but IgA and IgM, both β-globulins, are potential candidates. Objectives: The aims of this study were to measure serum IgG, IgA, and IgM in clinically healthy retired racing Greyhounds and compare the results with those of age- and sex-matched non-Greyhound dogs. Methods: Study animals included 25 Greyhound and 20 non-Greyhound dogs. Total protein, albumin, and total globulin concentrations were determined. IgG, IgA, and IgM concentrations were measured using a commercially available radial immunodiffusion kit. The Student t-test assuming equal variances was used to compare concentrations of immunoglobulins between groups. Results: Serum concentrations of IgA and IgM in Greyhounds (IgA=49±20 mg/dL; IgM=132±47 mg/dL) were significantly lower than concentrations in non-Greyound dogs (IgA=70±39 mg/dL; Ig M=212±78 mg/dL). Concentrations of IgG did not differ between groups. Conclusions: Mean serum IgA and IgM concentrations in Greyhounds were lower than those in non-Greyhound dogs. This may contribute to low serum concentrations of β-globulins in Greyhounds. Specific reference intervals are recommended for Greyhounds to avoid possible misdiagnosis of IgA or IgM deficiency.
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Prevalence of dog erythrocyte antigens in retired racing Greyhounds
Veterinary Clinical Pathology, 2010Co-Authors: M.c. Iazbik, L.m. Marín, Margee O'donnell, Sara Zaldivar, Dawn Hudson, C. Guillermo CoutoAbstract:Background: Blood groups in dogs are designated as dog erythrocyte antigen (DEA) 1.1, 1.2, 3, 4, 5, 7, and Dal. There is limited information about the frequency of different antigens in Greyhound dogs, despite their frequent use as blood donors. Objectives: The aims of this study were to determine the frequencies of DEA 1.1, 1.2, 3, 4, 5, and 7 in Greyhounds, to compare the frequencies with those of non-Greyhound dogs, and to evaluate the presence of naturally occurring anti-DEA antibodies. Methods: Blood was collected from 206 Greyhound and 66 non-Greyhound dogs being screened as potential blood donors. Blood-typing was performed at Animal Blood Resources International by tube agglutination utilizing polyclonal anti-DEA antibodies. Results: Of the Greyhound dogs, 27/206 (13.1%) were positive for DEA 1.1, and this frequency was significantly lower (P
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Results of a web-based health survey of retired racing Greyhounds.
Journal of Veterinary Internal Medicine, 2007Co-Authors: Linda K. Lord, L.m. Marín, Jill E. Yaissle, C. Guillermo CoutoAbstract:Background: Adoption of retired racing Greyhounds has become increasingly popular during the past decade. To date, research has focused on the physiologic and clinicopathologic peculiarities of Greyhounds but there is little published information on disease prevalence in the breed. Objective: The objective of this study is to determine the prevalence of disease in retired racing Greyhounds. Animals: In this study, 747 Greyhounds were used. Methods: A standardized survey method was used, and survey responses were collected by an Internet survey. Owners could answer a survey for every Greyhound that they had owned since January 1, 2005. Results: Of the 692 eligible participants, 441 (63.7% response rate) completed surveys for 747 Greyhounds. The mortality rate for Greyhounds within the 2-year period was 15% (113 of 747 died). The most common cause of death reported was cancer (66 dogs, 58%), and the most common type of cancer listed as the cause of death was osteosarcoma (28 dogs, 25%). The most commonly reported groups of diseases or disorders were skeletal (232 dogs, 33%), skin (197 dogs, 28%), digestive (132 dogs, 18%), cancer (94 dogs, 13%), and endocrine (85 dogs, 11.9%). Forty-five percent of Greyhounds diagnosed with cancer and 6% of the overall population had osteosarcoma. Conclusions and Clinical Importance: The results of this study can be used by veterinary researchers to continue to investigate the most common diseases in this population. As more retired racing Greyhounds enter the pet population, the results of this study will help educate veterinarians and owners about the most prevalent diseases in the breed.
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Comparison of Glomerular Filtration Rate between Greyhounds and Non‐Greyhound Dogs
Journal of Veterinary Internal Medicine, 2006Co-Authors: Tod Drost, C. Guillermo Couto, Anthony J. Fischetti, John S. Mattoon, Cristina IazbikAbstract:Greyhounds have significantly higher serum creatinine (SCr) concentration than do non-Greyhound dogs that may be attributable to differences in glomerular filtration rate (GFR). By means of plasma clearance of technetium Tc 99m diethylenetriaminepentaacetic acid, GFR was measured in 10 Greyhounds and 10 non-Greyhound dogs with normal findings of physical examination, CBC, serum biochemical analysis, and urinalysis. Dogs were fed the same diet for a minimum of 6 weeks before GFR data collection. Greyhounds had significantly higher mean 6 SD GFR (3.0 6 0.1 vs 2.5 6 0.2 ml/min/ kg; P 5 .01) and SCr concentration (1.8 6 0.1 vs 1.5 6 0.1 mg/dL; P 5 .03) than did non-Greyhound dogs, but the serum urea nitrogen (SUN) concentration was not significantly different (18 6 1 vs 18 6 2 mg/dL; P 5 .8). Therefore, the higher SCr concentration in Greyhounds is not attributable to decreased GFR, and may be associated with the high muscle mass in the breed. Healthy Greyhounds have higher GFR than do non-Greyhound dogs.
Timothy J. Lawes - One of the best experts on this subject based on the ideXlab platform.
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fractographic examination of racing Greyhound central navicular tarsal bone failure surfaces using scanning electron microscopy
Calcified Tissue International, 2000Co-Authors: J L Tomlin, Timothy J. Lawes, Gordon W. Blunn, Allen E. Goodship, P. MuirAbstract:The Greyhound is a fatigue fracture model of a short distance running athlete. Greyhounds have a high incidence of central (navicular) tarsal bone (CTB) fractures, which are not associated with overt trauma. We wished to determine whether these fractures occur because of accumulation of fatigue microdamage. We hypothesized that bone from racing dogs would show site-specific microdamage accumulation, causing predisposition to structural failure. We performed a fractographic examination of failure surfaces from fractured bones using scanning electron microscopy and assessed microcracking observed at the failure surface using a visual analog scale. Branching arrays of microcracks were seen in failure surfaces of CTB and adjacent tarsal bones, suggestive of compressive fatigue failure. Branching arrays of microcracks were particularly prevalent in remodeled trabecular bone that had become compact. CTB fractures showed increased microdamage when compared with other in vivo fractures (adjacent tarsal bone and long bone fractures), and ex vivo tarsal fractures induced by monotonic loading (P < 0.02). It was concluded that Greyhound racing and training often results in CTB structural failure, because of accumulation and coalescence of branching arrays of fatigue microcracks, the formation of which appears to be predisposed to adapted bone.
Gordon W. Blunn - One of the best experts on this subject based on the ideXlab platform.
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fractographic examination of racing Greyhound central navicular tarsal bone failure surfaces using scanning electron microscopy
Calcified Tissue International, 2000Co-Authors: J L Tomlin, Timothy J. Lawes, Gordon W. Blunn, Allen E. Goodship, P. MuirAbstract:The Greyhound is a fatigue fracture model of a short distance running athlete. Greyhounds have a high incidence of central (navicular) tarsal bone (CTB) fractures, which are not associated with overt trauma. We wished to determine whether these fractures occur because of accumulation of fatigue microdamage. We hypothesized that bone from racing dogs would show site-specific microdamage accumulation, causing predisposition to structural failure. We performed a fractographic examination of failure surfaces from fractured bones using scanning electron microscopy and assessed microcracking observed at the failure surface using a visual analog scale. Branching arrays of microcracks were seen in failure surfaces of CTB and adjacent tarsal bones, suggestive of compressive fatigue failure. Branching arrays of microcracks were particularly prevalent in remodeled trabecular bone that had become compact. CTB fractures showed increased microdamage when compared with other in vivo fractures (adjacent tarsal bone and long bone fractures), and ex vivo tarsal fractures induced by monotonic loading (P < 0.02). It was concluded that Greyhound racing and training often results in CTB structural failure, because of accumulation and coalescence of branching arrays of fatigue microcracks, the formation of which appears to be predisposed to adapted bone.
