Prevalence, radiographic resolution and outcomes of slab fractures of the third and central tarsal bones in juvenile Thoroughbred horses.

BACKGROUND: Veterinarians are required to interpret the significance of radiographic findings for sale, soundness and future racing performance of weanling and yearling Thoroughbreds. We investigated the prevalence and radiographic appearance of slab fractures of the third (T3) and central tarsal (Tc) bones. METHODS: Weanling and yearling horses with complete or incomplete T3 or Tc fracture were identified by searching a database of radiographs. The prevalence and radiographic appearance at initial diagnosis and after continued pasture turnout, as well as prognosis for racing, of fractures of T3 and Tc were determined. RESULTS: Fractures were identified in 186 tarsi (184 T3 fracture only, 1 Tc fracture only, 1 Tc and T3 fracture) of 157 horses (126 unilateral T3, 29 bilateral T3, 1 contralateral Tc and T3, 1 unilateral Tc and T3) from 7676 examinations. The prevalence of T3 and Tc fractures was 2.40 (95% CI 2.07, 2.76) and 0.04 (95% CI 0.01, 0.11) per 100 radiographic examinations respectively. Fractures were identified on the D556-65°MPlLO view and occurred by survey examination at 11.1 ± 1.3 months in 85.7% horses. At initial diagnosis, 84.3% of T3 fractures appeared incomplete and involved the distal articular surface. Fracture score improved (P < 0.001), and dorsal modelling (P < 0.001) and osteoarthritis score increased in the distal intertarsal joint (P < 0.001), but not the tarsometatarsal joint, between survey and repository examinations. Fractures healed by repository examination in 71.9% of tarsi if there was > 6 months between examinations. There was no difference in sale price, and horses with T3 fractures had fewer trials when 2 and 3 years old (P = 0.023), yet no difference in other parameters of racing success when 2 or 3 years old compared with controls. CONCLUSION: Tarsal slab fractures can occur in juvenile Thoroughbreds and most heal with continued pasture turnout of > 6 months. Further investigation is required to determine risk factors and before making firm conclusions regarding the optimal management, prognosis for racing and long-term soundness.

Survey of trainers on the use of swimming exercise for Standardbred racehorses in Australia.

OBJECTIVES: To determine swimming training practices in Australian harness racing horses and potential targets for future research. METHODS: An online survey of Australian Standardbred trainers and telephone interviews with 20 leading trainers were conducted. Questions relating to swimming facility and protocol, perceived benefits and contraindications were included. Descriptive data analysis was performed. RESULTS: Data were collected from 270 trainers: 250 by online survey (250/1770, response rate 14.1%) and 20 by interview. Of these, 103 trainers (38.1%), including 91 surveyed trainers (91/250, 36.4%) and 12 interviewed trainers (12/20, 60.0%), used swimming exercise. The most popular reasons for swimming were to replace trackwork for horses with limb injuries (79.4%), improve or maintain fitness (62.7%) and provide mental stimulation through variety in training (40.0%). Free swimming (78.4%) was more common than tethered, but the frequency and duration for horses in full training varied widely between trainers, with a median of four swim sessions per horse each week (range 0.5-12) for a median of 7 min (range 1.5-30 min) per session, mostly as a continuous swim, but sometimes as intervals. The main reasons given by those not swimming horses were lack of an adequate facility (60.5%) and lack of perceived benefit (16.2%). Reasons for not swimming individual horses varied widely. CONCLUSIONS: Trainer opinions and protocols varied widely with respect to swimming exercise for Standardbred race horses. The role of swimming exercise requires further study so that evidence-based recommendations can be made.

Fragmentation of the dorsal distal aspect of the talus on weanling survey and pre-sale radiographs of juvenile Thoroughbreds: prevalence and 2- and 3-year-olds racing performance.

BACKGROUND: Fragmentation of the dorsal aspect of the distal talus (FDDT), at the dorsolateral articular margin of the proximal intertarsal joint (PITJ) on pre-sale radiographs of yearling Thoroughbreds has not been previously described and data to support decisions made by veterinarians to predict future racing potential of horses with these lesions are lacking. METHODS: In this retrospective case-control study we aimed to determine the prevalence of FDDT in juvenile Thoroughbreds and to report their race records. From a database of survey and repository radiographic examinations of 5709 horses, 36 with FDDT were identified. RESULTS: The prevalence of FDDT was 0.63% (36/5709; 95%CI 0.44, 0.87), compared with 5.01% (286/5709; 95%CI 4.46, 5.61) for osteochondrosis of the distal intermediate ridge of the tibia in the same population. In most cases, a single oval-shaped fragment 1-12 mm in diameter was present. When comparing cases with matched controls, there were no significant differences in mean sale price, whether horses started in a trial or race and mean number of starts, wins, places and prize money when 2- and 3-years old. CONCLUSION: FDDT did not appear to affect racing performance, although a larger-scale study is warranted to confirm this finding.

Risk of septic arthritis after intra-articular medication: a study of 16,624 injections in Thoroughbred racehorses.

OBJECTIVES: The aims of this study were to determine the risk of septic arthritis after intra-articular medication (IAM) and to identify potential risk factors for this complication. DESIGN: A retrospective and prospective descriptive study of prevalence, and matched case-control study for risk factors. RESULTS: Of 16,624 joints injected in 1103 horses at 6695 horse-visits, septic arthritis occurred as a complication in 13 joints (13 horses). The risk of septic arthritis following IAM was 7.8 cases per 10,000 injections or 1 case per 1279 injections. Veterinarian and type of corticosteroid were identified as risk factors. CONCLUSIONS: Septic arthritis is an uncommon complication of IAM in horses, yet the risk is substantially higher than that reported in humans. The risk was higher for some veterinarians; identifying the reason for this was beyond the scope of this study, yet we presume they may have paid less attention to strict aseptic technique. A larger study may be needed to clarify whether the risk is greater with certain types of corticosteroids and to identify additional risk factors.

Muscle strain injuries of the hindlimb in eight horses: diagnostic imaging, management and outcomes.

OBJECTIVE: To describe the clinical presentation, ultrasound findings, management and outcome in horses with muscle tear injuries of the hindlimbs. DESIGN: Retrospective case series Procedure Medical records of eight horses were reviewed and information on signalment, history, presenting complaint, physical examination findings and further diagnostic tests were recorded. Diagnosis of muscle injury was determined by the presence of abnormal ultrasound findings, compared with the contralateral limb, and, when required, nuclear scintigraphy. Follow-up information was obtained via telephone interviews with owners, trainers and referring veterinarians. RESULTS: Muscle tears causing lameness were identified in the middle gluteal (3), semitendinosus (1), semimembranosus (2) and gracilis (2) muscles. Tears were classified by ultrasound imaging as partial (6) or complete (2). The degree of lameness did not appear to be indicative of the extent of injury or of completion of healing. Long-term follow-up was available for seven horses and the outcome was favourable in six cases. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasonography is useful in the diagnosis and assessment of moderate to severe muscle strain injuries. The prognosis appears to be favourable in most cases, although recurrence of injury and lameness can delay the return to athletic activity and an inferior outcome with persistent gait abnormality may occur.

T-shaped malformation of the ventral colon in a Thoroughbred filly with colic.

A 4-month-old Thoroughbred filly presented for abdominal pain was diagnosed with a T-shaped malformation of the ventral colon at exploratory laparotomy. Following resection and anastomosis of the large colon, no further episodes of abdominal pain occurred during a 12-month follow-up. Acute dehiscence of the linea alba occurred as a complication of the initial laparotomy, but was successfully managed following additional surgical repair. T-shaped malformation of the ventral colon has not previously been reported and is considered a congenital malformation of mesocolon formation.

Regional distribution of collagen and haemosiderin in the lungs of horses with exercise-induced pulmonary haemorrhage.

REASONS FOR PERFORMING STUDY: Regional veno-occlusive remodelling of pulmonary veins in EIPH-affected horses, suggests that pulmonary veins may be central to pathogenesis. The current study quantified site-specific changes in vein walls, collagen and haemosiderin accumulation, and pleural vascular profiles in the lungs of horses suffering EIPH. HYPOTHESIS: In the caudodorsal lung regions of EIPH-affected horses, there is veno-occlusive remodelling with haemosiderosis, angiogenesis and fibrosis of the interstitium, interlobular septa and pleura. METHODS: Morphometric methods were used to analyse the distribution and accumulation of pulmonary collagen and haemosiderin, and to count pleural vascular profiles in the lungs of 5 EIPH-affected and 2 control horses. RESULTS: Vein wall thickness was greatest in the dorsocaudal lung and significantly correlated with haemosiderin accumulation. Increased venous, interstitial, pleural and septal collagen; lung haemosiderin; and pleural vascular profiles occurred together and changes were most pronounced in the dorsocaudal lung. Further, haemosiderin accumulation colocalised with decreased pulmonary vein lumen size. Vein wall thickening, haemosiderin accumulation and histological score were highly correlated and these changes occurred only in the caudodorsal part of the lung. CONCLUSION: The colocalisation of these changes suggests that regional (caudodorsal) venous remodelling plays an important role in the pathogenesis of EIPH. POTENTIAL RELEVANCE: The results support the hypothesis that repeated bouts of venous hypertension during strenuous exercise cause regional vein wall remodelling and collagen accumulation, venous occlusion and pulmonary capillary hypertension. Subjected to these high pressures, there is capillary stress failure, bleeding, haemosiderin accumulation and, subsequently, lung fibrosis.

Regional pulmonary veno-occlusion: a newly identified lesion of equine exercise-induced pulmonary hemorrhage.

Exercise-induced pulmonary hemorrhage (EIPH) is common in horses following intense exertion, occurring in up to 75% of racing Thoroughbreds and Standardbreds. In spite of this, the pathogenesis of EIPH is poorly understood. In 7 racing Thoroughbred horses with EIPH, 6 sections were collected from the left and right lung, representing the cranial, middle, and caudal region of the dorsal and ventral lung (84 sites total). Grossly, both right and left lungs had numerous dark brown to blue-black foci along the caudodorsal visceral pleura. Tissue sections were stained with hematoxylin-eosin, Masson's trichrome, and Prussian blue. Verhoeff Van Gieson and immunohistochemistry for alpha-smooth muscle actin were used to assess the pulmonary vasculature. Histologic scores (HS = 0-3) were assigned to each region/slide for the presence and severity of 5 findings: interstitial fibrosis, hemosiderin accumulation, pleural/interlobular septal thickness, arterial and venous wall thickness, and evidence of angiogenesis (maximum cumulative HS = 15). Thirty-nine of the 84 (46%) sections were histologically normal (HS = 0); 33/84 (39%) were mildly to moderately affected, with small amounts of hemosiderin and fibrosis (HS = 1-9) while 12/84 (14%), primarily from the dorsocaudal lung, had severe vascular remodeling, fibrosis, and hemosiderin accumulation (HS = 10-15). In the latter, veno-occlusive remodeling of the intralobular veins colocalized with hemosiderosis, fibrosis, hypertrophy of vessels within the pleura, and interlobular septa and bronchial neovascularization. We propose that regional veno-occlusive remodeling, especially within the caudodorsal lung fields, contributes to the pathogenesis of EIPH, with the venous remodeling leading to regional vascular congestion and hemorrhage, hemosiderin accumulation, fibrosis, and bronchial angiogenesis.

Clinical findings, diagnosis, prevalence and predisposing factors for lameness localised to the middle carpal joint in young Standardbred racehorses.

REASONS FOR PERFORMING STUDY: Lameness related to the middle carpal joint (MCJ) occurs in up to 30% of young Standardbred horses in race training and the incidence increase with radiographic severity of third carpal bone (C3) sclerosis on DPr-DDIO (skyline) view of the carpus. Factors predisposing horses to carpal injury have not been well investigated. OBJECTIVES: To determine the importance of MCJ lameness as a cause of wastage in young Standardbred racehorses, stage of training at which it occurs and predisposing factors, and to describe clinical findings and diagnosis. METHODS: Standardbred horses (n = 114) entering their first year of race training were examined at approximately 3-month intervals over 12-18 months. For 87 of the horses, a training diary was available and these horses were trained at 3 different stables, each using a different exercise regime. At each examination, forelimb conformation, MCJ effusion, MCJ lameness and radiographic findings were graded, and training history and reasons for lost training days recorded. Nuclear scintigraphy and exploratory arthroscopy were performed on a limited selection of horses. Results for horses that developed MCJ lameness during the study period were compared statistically with results for horses that did not. RESULTS: Carpal lameness occurred in 28% of horses and was present in 56% with forelimb lameness. In most cases lameness was mild, bilateral and with little or no MCJ effusion and was attributed to subchondral bone pain associated with radiographic evidence of C3 sclerosis. Carpal lameness was the most common reason for >1 month's rest during the study period. It occurred at any stage of training but, in most cases, some speed training had begun. Of the variables studied, poor forelimb conformation and more intense speed training were predisposing factors. CONCLUSIONS AND POTENTIAL RELEVANCE: The information gained should assist in making recommendations regarding training young Standardbreds to reduce the incidence of MCJ lameness. However, further investigations to determine the optimal training regime are warranted.

Investigation of the reliability of 24 h urine excretion as a biomarker of isoflavone exposure over time and over a wide range of isoflavone intakes.

OBJECTIVE: To study the variation in genistein + daidzein intake over a 6-month period and test the reliability of 24 h urinary isoflavones as a biomarker of exposure over time. DESIGN: Dietary genistein + daidzein intake was assessed at various time points throughout six months in 15 healthy subjects. Group 1 (n=8) followed nonsupplemented diets and Group 2 (n=7) took a 35 mg/d isoflavone supplement for 3 months and each subject provided a 24 h urine collection, validated with para-aminobenzoic acid, during weeks 7, 15 and 19. Urine was analysed for genistein and daidzein using LC-MS. RESULTS: Isoflavone intake in Groups 1 and 2 ranged from 0.00 to 1.1 mg/d and 0.1 to 53.1 mg/d, respectively. Urine excretion for both groups ranged from 0.20 to 9.56 mg/d. The relationship between 24 h excretion and isoflavone intake is y=0.44 x +/- 0.03(standard deviation) + 1.57; r=0.89, P<0.001. CONCLUSION: The 24 h urinary isoflavones can be used as biomarkers of isoflavone exposure over time.

Karyotypic aberrations of chromosomes 16 and 17 are related to survival in patients with breast cancer.

BACKGROUND: Breast cancer has a high incidence and associated mortality rate, yet little is known of the sequence of genetic events that underlie the clinical course. METHODS: The study was a comparative genomic hybridization analysis of 40 primary breast cancers with survival data at a mean of 8.4 years. RESULTS: The mean number of aberrations was 9.0, with a mean of 5.5 gains and 3.5 deletions per tumour. The most common aberrations were: gain of 1q (27 of 40), 8q (19 of 40) and 17q (13 of 40), and deletion of 17p (12 of 40) and 8p (11 of 40). These results are consistent with a distinctive pattern of large-scale (karyotypic) genetic change in primary breast cancer. CONCLUSION: The novel findings of this study were that only women who were disease-free had loss of 16q (E-cadherin) in association with a gain of 16p, and 17p13 (p53) loss combined with 17q12 (HER2) amplification was found only in the cancers of women who developed recurrent disease. The karyotypic changes seen in primary breast cancer seem to be associated with outcome and point to the underlying genetic events.

The G2 chromosomal radiosensitivity assay.

Although requiring stringent experimental conditions to achieve good reproducibility, the G2 assay has potential as a sensitive marker for cancer susceptibility, and is particularly useful in population studies. Immediate culture of blood is preferable, but overnight storage of blood either at ambient temperature or at 4 degrees C does not appear significantly to affect G2 scores. Transport of blood may lead to additional variability in assay results and should be well controlled. Although reproducibility is generally good, G2 scores on blood from certain individuals appear to show significant variability in repeat samples. Thus, determination of an individual's radiosensitivity may require multiple assays on different occasions. While it is recognized that the distinction between aligned and mis-aligned discontinuities has no scientific basis, some laboratories have decided for the purpose of record-keeping to score all aligned discontinuities as gaps, and mis-aligned discontinuities as breaks. In all cases the final G2 score should comprise the sum of all gaps and breaks.

The UK national study of magnetic resonance imaging as a method of screening for breast cancer (MARIBS).

The UK national study of magnetic resonance imaging as a method of screening for breast cancer (MARIBS) is in progress. The study design, accrual to date, and related research projects are described. Revised accrual rates and expected recruitment are given. 15 cancers have been detected to date, from a total of 1236 screening measurements. This event rate and the tumour grades reported are compared with recent reports from other studies in women at high risk of breast cancer.

Chromosomal radiosensitivity in G2-phase lymphocytes identifies breast cancer patients with distinctive tumour characteristics.

A substantial proportion of women with breast cancer exhibit an abnormally high radiosensitivity as measured by the frequency of chromatid breaks induced in G2-phase, PHA stimulated lymphocytes. Chromatid break frequencies were compared for a cohort of previously untreated sporadic breast cancer patients and hospital outpatient controls. In the breast cancer group 46% showed high radiosensitivity compared to 14% of controls (P< 0.001). Comparison of those breast cancer patients with a high G2 radiosensitivity (G2RS) versus those with a low G2RS showed no difference in menopausal status or age but the high G2RS group had on average a lower score on the Nottingham Prognostic Index. Predicted survival in the high G2RS group at 15 years was 55% compared to 36% for the low G2RS group. Furthermore, 81% of tumours from the high G2RS were oestrogen receptor positive compared to 45% from the low G2RS group. Thus high G2RS identifies a sub-population of patients with distinctive tumour characteristics and with a predicted improved prognosis as compared with those in the low G2RS group. Our findings imply that besides influencing risk of breast cancer the genetic factors determining G2 radiosensitivity also influence the tumour characteristics and prognosis in these patients.

Cancer risk perceptions and distress among women attending a familial ovarian cancer clinic.

Of 230 women referred to a familial ovarian cancer clinic, 196 (85%) completed a questionnaire before they attended. The data collected included pre-counselling risk perceptions and an assessment of distress. Respondents were more likely to underestimate (44%) than overestimate (19%) their risk. Those with a family history of breast and ovarian cancer (HBOC) were particularly likely to underestimate their ovarian cancer risk. The variables assessed in this study - sociodemographic, family history, distress, anxiety proneness, coping style and beliefs about health control - explained little of the observed variation in accuracy of risk perception. On the General Health Questionnaire (GHQ-30) 30% of the sample obtained scores above the cut-off (>/= 6) recommended for screening for 'case-level' psychological distress. Women exhibiting case-level distress were more likely to overestimate their risk (OR = 2.3). On univariate analysis low internal locus of control was associated with 'case-level' distress (P = 0.008). On multiple regression the best predictors of 'caseness' were high-trait anxiety, being a graduate and inaccurate risk perception. There was no difference in the level of distress shown by women with HBOC vs. those with a history of ovarian cancer only. Implications of these findings for the counselling needs of the women are discussed. The effectiveness of the clinic in improving the accuracy of risk perceptions and relieving distress is being assessed.

Surgical arthrodesis of distal tarsal joints in 17 horses clinically affected with osteoarthritis.

OBJECTIVE: To evaluate the outcome of 17 horses that underwent surgical arthrodesis of the tarsometatarsal and distal intertarsal joints for treatment of lameness due to osteoarthritis. DESIGN: Retrospective clinical study using client-owned animals. PROCEDURE: Horses with hindlimb lameness were diagnosed with osteoarthritis of the distal tarsal joints following relief of lameness after intra-articular anaesthesia or intra-articular corticosteroid injection. Surgery to stimulate ankylosis was performed on 27 hocks by placing 3 diverging 3.2 mm drill holes approximately 3 cm through the tarsometatarsal and distal intertarsal joints from the medial aspect of the limb. The results of surgery were assessed by postoperative examinations, telephone communication with clients and analysis of race results. RESULTS: In 71% of horses, surgery was considered to be successful as determined by clinical examination or telephone communication with clients: six of these horses had unilateral surgery and six had bilateral surgery. This represented 85% (6/7) of horses undergoing unilateral surgery and 60% (6/10) of horses having bilateral surgery. All (8/8) racing Standardbreds and 67% (4/6) of racing Thoroughbreds were considered a success. The average time between surgery and a return to racing was 9.5 months. CONCLUSIONS: The surgical technique used here can provide resolution of lameness from osteoarthritis of distal tarsal joints with a success rate similar to other reported surgical arthrodesis techniques that are more invasive and have a greater morbidity.

Women at risk of ovarian cancer: attitudes towards and expectations of the familial ovarian cancer clinic.

Familial ovarian cancer clinics are a recent development and little is known about the characteristics of women who attend. One hundred and ninety-seven women with a family history of ovarian cancer completed a questionnaire prior to their initial attendance at the Familial Ovarian Cancer Clinic in Edinburgh. Issues relating to screening procedures were the most commonly cited barriers to attendance, with a proportion finding gynaecological examination embarrassing (17.0%) or uncomfortable (18.0%). Expectations of the clinic were high in terms of access to resources and information. The vast majority of women would prefer to have regular screening (94.7%) and genetic testing (93.2%) if it were available. Attitudes to prophylactic surgery and chemoprevention were more diverse, but would be considered by 54.3% and 43.9% of respondents respectively. Although the current screening procedure for ovarian cancer is of unproven efficacy, a high proportion of women believed in its ability to reduce mortality (77.9%) and to detect tumours at an early stage (65.8%). There was a trend for women to believe this more strongly at follow-up. This study highlights the need to make women more aware of the limitations of current ovarian cancer screening techniques, particularly where the alternative management strategy of prophylactic surgery might otherwise be dismissed.

Improving the predictability of performance by prerace detection of dorsal metacarpal disease in thoroughbred racehorses.

OBJECTIVE: To determine the prevalence of dorsal metacarpal disease in 2-year-old Thoroughbred horses by prerace inspection and to evaluate the effectiveness of a dorsal metacarpal disease detection program on the predictability of race performance (finishing in the order predicted by punters) and the distance between the first- and last-placed horse in a field. DESIGN: A retrospective study using client-owned horses. METHODS: A program of prerace detection of dorsal metacarpal disease using digital palpation of the dorsal aspect of the third metacarpal bone of both forelimbs of 2-year-old Thoroughbreds racing at Ascot racecourse was instituted by the Western Australian Turf Club in December 1995. Horses that had significant pain reaction to digital palpation were considered to have pain due to dorsal metacarpal disease, withdrawn from that day's race and not permitted to race for 6 weeks. The race records of all 2-year-old Thoroughbreds racing at Ascot racecourse from December 1993 until December 1995 were compared with the race results from December 1995 until March 1997, after initiation of the dorsal metacarpal disease detection program. RESULTS: After initiation of the program, horses were racing more predictably over 1100 m (P = 2.09) and 1200 m (P = 3.48). These horses finished closer to the winner over 1100 m (P = 3.39) and over 1200 m (P = 3.13). In 1000 m races, the trend for horses to race more predictably (P = 1.07) and for there to be less distance between first and last (P = 1.72) was not statistically significant. CONCLUSIONS: The program of prerace digital palpation for dorsal metacarpal disease was considered to be beneficial in 2-year-old Thoroughbreds racing over 1100 m and 1200 m, in that they raced more predictably.