A review of international clinical practice guidelines for the use of oxygen in the delivery room resuscitation of preterm infants.

AIM: To collate and assess international clinical practice guidelines (CPG) to determine current recommendations guiding oxygen management for respiratory stabilisation of preterm infants at delivery. METHODS: A search of public databases using the terms 'clinical practice guidelines', 'preterm', 'oxygen' and 'resuscitation' was made and complemented by direct query to consensus groups, resuscitation expert committees and clinicians. Data were extracted to include the three criteria for assessment: country of origin, gestation and initial FiO2 and target SpO2 for the first 10 minutes of life. RESULTS: A total of 45 CPGs were identified: 36 provided gestation specific recommendations (<28 to <37 weeks) while eight distinguished only between 'preterm' and 'term'. The most frequently recommended initial FiO2 were between 0.21 and 0.3 (n = 17). Most countries suggested altering FiO2 to meet SpO2 targets recommended by expert committees, However, specific five-minute SpO2 targets differed by up to 20% (70-90%) between guidelines. Five countries did not specify SpO2 targets. CONCLUSION: CPG recommendations for delivery room oxygen management of preterm infants vary greatly, particularly in regard to gestational ages, initial FiO2 and SpO2 targets and most acknowledge the lack of evidence behind these recommendations. Sufficiently large and well-designed randomised studies are needed to inform on this important practice.

Resuscitating preterm infants with 100% oxygen is associated with higher oxidative stress than room air.

AIM: The starting fraction of inspired oxygen for preterm resuscitation is a matter of debate, and the use of room air in full-term asphyxiated infants reduces oxidative stress. This study compared oxidative stress in preterm infants randomised for resuscitation with either 100% oxygen or room air titrated to internationally recommended levels of preductal oxygen saturations. METHODS: Blood was collected at birth, two and 12 hours of age from 119 infants <32 weeks of gestation randomised to resuscitation with either 100% oxygen (n = 60) or room air (n = 59). Oxidative stress markers, including advanced oxidative protein products (AOPP) and isoprostanes (IsoP), were measured with high-performance liquid chromatography and mass spectrometry. RESULTS: Significantly higher levels of AOPP were found at 12 hours in the 100% oxygen group (p < 0.05). Increases between two- and 12-hour AOPP (p = 0.004) and IsoP (p = 0.032) concentrations were significantly higher in the 100% oxygen group. CONCLUSION: Initial resuscitation with room air versus 100% oxygen was associated with lower protein oxidation at 12 hour and a lower magnitude of increase in AOPP and IsoP levels between two and 12 hours of life. Correlations with clinical outcomes will be vital to optimise the use of oxygen in preterm resuscitation.

Urine congophilia associated with preeclampsia does not persist 6-months postpartum.

INTRODUCTION: Preeclampsia is a common hypertensive disorder of pregnancy. Several studies have demonstrated that protein aggregates, detected through urine congophilia, is associated with preeclampsia; however, it has yet to be investigated whether urine congophilia remains postpartum in these women. In this study, we aimed to augment prior studies and determine whether urine congophilia is present postpartum. METHODS: Women were recruited from Lyell McEwin Hospital, South Australia. Urine samples were collected during pregnancy and 6-months postpartum from women with non-preeclampsia pregnancies (n = 48) and women with pregnancies complicated by preeclampsia (n = 42). A Congo Red Dot blot test, total protein and creatinine levels from urine, as well as serum Soluble fms-like tyrosine kinase 1 to placental growth factor ratio (sFlt-1:PlGF), were assessed and correlated. RESULTS: Preeclamptic women exhibited increased urine congophilia (P < 0.01), sFlt-1:PlGF ratio (P < 0.0001) and total protein (P < 0.01) during pregnancy; with a positive correlation between urine congophilia and total protein across the entire cohort (P < 0.0001). Although urine congophilia was no longer detected 6-months postpartum in preeclamptic women, total protein remained elevated (P < 0.05). sFlt-1:PlGF ratio during pregnancy was positively correlated with congophilia across the cohort (P = 0.0007). Serum creatinine was also higher in preeclamptic women during pregnancy (P < 0.001). DISCUSSION: These results support that urine congophilia is significantly elevated in pregnancies complicated with preeclampsia and show that it does not continue postpartum, although larger cohort studies are needed to determine its feasibility as a diagnostic marker.

The susceptibility of Culicoides imicola and other South African livestock-associated Culicoides species to infection with bluetongue virus serotype 8.

In 2006, a strain of bluetongue virus serotype 8 (BTV-8) of sub-Saharan origin was responsible for the first outbreaks in recorded history of clinical bluetongue disease (BT) in northern Europe. In this study, we examine the oral susceptibility of Culicoides (Avaritia) imicola Kieffer (Diptera: Ceratopogonidae) and other livestock-associated Culicoides species from southern Africa to infection with several strains of BTV-8. Following feeding using an artificial membrane-based method and incubation, virus was found in <1% of C. imicola individuals tested. Higher rates of susceptibility were found, however, for a variety of other South African species, including Culicoides (Avaritia) bolitinos Meiswinkel. Although these results do not preclude the role of C. imicola as a vector of BTV-8, its low susceptibility to BTV indicates that other less abundant Culicoides species may have the potential to play decisive roles in the epidemiology of this virus and should not be excluded from risk assessment studies.

The use of small (2.7 mm) screws for arthroscopically guided repair of carpal chip fractures.

REASONS FOR PERFORMING THE STUDY: Removal of large chip fractures of the carpal bones and the osteochondral deficits that result, have been associated with a worse prognosis than removal of small fragments in similar locations. HYPOTHESIS: Reducing the articular defects by repair of large osteochondral fragments may have advantages over removal. METHODS: Horses with osteochondral chip fractures that were of sufficient size and infrastructure to be repaired with small (2.7 mm diameter) AO/ASIF cortex screws were identified and repair effected by arthroscopically guided internal fixation. RESULTS: Thirty-three horses underwent surgery to repair 35 fractures of the dorsodistal radial carpal bone (n = 25), the dorsal margin of the radial facet of the third carpal bone (n = 9) and the intermediate facet of the distal radius (n = 1). There were no surgical complications and fractures healed satisfactorily in 26 of 28 horses and 23 horses returned to racing performance. CONCLUSION: Arthroscopically guided repair of carpal chip fractures with small diameter cortex screws is technically feasible and experiences with 33 cases suggest that this may have advantages over fragment removal in managing such cases. POTENTIAL RELEVANCE: Surgeons treating horses with large chip fractures of the carpal bones should consider arthroscopically guided internal fixation as an alternative to removal.

Arthroscopic treatment of fractures of the lateral malleolus of the tibia: 26 cases.

REASONS FOR PERFORMING THE STUDY: A minimally invasive arthroscopic technique for removal of fractures of the lateral malleolus of the tibia is considered to be beneficial but data to this effect are required. HYPOTHESIS: Arthroscopic removal of fractures of the lateral malleolus of the tibia is technically feasible, provides a comprehensive evaluation of the tarsocrural joint and enables removal of remote comminuted fragments and disrupted short collateral ligaments. The technique is associated with low patient morbidity, requires only short periods of hospitalisation and affords a good prognosis to affected horses. METHODS: The case records of all horses that underwent arthroscopic removal of a fractured lateral malleolus of the tibia, admitted to a referral hospital, were evaluated retrospectively. Follow-up information was obtained from race records and by telephone questionnaire. RESULTS: Fractures were successfully removed arthroscopically in all cases following dissection from the short lateral collateral ligaments. Significant post operative complications occurred in only one horse. All other horses recovered well from surgery and of 22 horses with long-term follow-up, 18 returned to their previous use. CONCLUSION: Arthroscopic removal of fractures of the lateral malleolus of the tibia is technically demanding, but can be performed with minimal complications and with low patient morbidity and short periods of hospitalisation. The majority of horses are able to successfully return to work following the procedure. POTENTIAL RELEVANCE: The advantages of arthroscopic removal compared to removal via arthrotomy make this the technique of choice for treatment of fractures of the lateral malleolus of the tibia.

A comparison of the susceptibility of the biting midge Culicoides imicola to infection with recent and historical isolates of African horse sickness virus.

The susceptibility of Culicoides (Avaritia) imicola Kiefer (Diptera: Ceratopogonidae) to 21 isolates representing all nine known serotypes of African horse sickness virus (AHSV), recovered from clinical cases of the disease in South Africa during 1998-2004, was compared with its susceptibility to approximately 40-year-old isolates stored at the Agricultural Research Council-Onderstepoort Veterinary Institute. Field-collected C. imicola were fed through a chicken skin membrane on sheep blood spiked with one of the virus isolates to a concentration in the range of 5.6-7.5 log (10)TCID(50)/mL. After 10 days incubation at 23.5 degrees C, five of the nine historical serotypes (AHSV-1, -2, -3, -7 and -9) could not be isolated from C. imicola. All nine serotypes were recovered for the 21 recent isolates, for 16 of which the virus recovery rates were higher than for the corresponding historical isolates. These results emphasize the need to assess the oral susceptibility of local Culicoides populations to viruses in circulation during outbreaks in order to estimate their vector potential.

Radiographic and arthroscopic features of third carpal bone slab fractures and their impact on racing performance following arthroscopic repair in a population of racing Thoroughbreds in the UK.

BACKGROUND: Slab fractures of the third carpal bone (C3) are a common injury of Thoroughbred racehorses. Results of arthroscopically guided repair have not been reported since the initial description of the technique in 1986. Additionally, fracture details and racing outcomes in a population of Thoroughbreds racing under UK jurisdiction have not previously been described. OBJECTIVES: To report the frequency distribution of C3 slab fractures and to determine the impact on racing performance following arthroscopically guided repair in a population of Thoroughbred racehorses. STUDY DESIGN: Retrospective case series. METHODS: Case records of Thoroughbred racehorses undergoing arthroscopically guided repair of C3 slab fractures at Newmarket Equine Hospital between 2006 and 2015 were retrieved. Radiographs and arthroscopic studies were reviewed. The effect of demography and fracture morphology on racing outcome was evaluated. RESULTS: C3 slab fractures occurred most commonly through the radial facet in a frontal plane (45/71 63.4%). Comminution was identified during arthroscopy in 42/71 (59.2%) fractures and occurred most frequently at the palmar margin of the fracture. Forty-one out of 65 horses (63.1%) raced at least once post-operatively. Females were less likely to return to racing compared to males (P<0.001). Horses that had raced before injury were more likely (OR 4.4, 95% CI 1.4-13.5, P = 0.01) to race after injury compared to horses that were unraced at the time of injury. After injury horses had a small but significant reduction in racing performance. MAIN LIMITATIONS: The series is a preselected population of Thoroughbred racehorses which referring veterinary surgeons considered potential candidates for surgical repair. CONCLUSION: Fracture configurations can be identified radiographically but is not a reliable predictor of comminution or other intra-articular lesions. Arthroscopy not only directs repair but also identifies and facilitates management of concurrent lesions. The results reported should assist in formulating appropriate prognoses for Thoroughbred horses racing in the UK.

The oral susceptibility of South African field populations of Culicoides to African horse sickness virus.

Twenty-two isolates of African horse sickness virus (AHSV), representing its distinct serotypes, geographical and historical origins, were fed to three populations of South African livestock-associated Culicoides spp. (Diptera, Ceratopogonidae). Infective blood meals included 12 recent isolates, nine historical reference strains and one live attenuated vaccine strain serotype 7 (AHSV-7) of the virus. Field-collected midges were fed through a chicken-skin membrane on sheep blood spiked with one of the viruses, which concentrations ranged from 5.4 to 8.8 log(10)TCID(50)/mL of blood. After 10 days incubation at 23.5 degrees C, AHSV was isolated from 11 Culicoides species. Standard in vitro passaging of AHSV-7, used for the preparation of live attenuated vaccine, did not reduce its ability to infect Culicoides species. Virus recovery rates in orally infected Culicoides midges differed significantly between species and populations, serotypes, isolates and seasons. Significant variations in oral susceptibility recorded in this study emphasize a complex inter-relationship between virus and vector, which is further influenced by multiple intrinsic and extrinsic factors. As it is not possible to standardize all these factors under laboratory conditions, conclusive assessment of the role of field-collected Culicoides midges in the transmission of orbiviruses remains problematic. Nevertheless, results of this study suggest the potential for multi-vector transmission of AHSV virus in South Africa.

Surgical management of marginal tears/avulsions of the suspensory ligament branches in 29 Thoroughbred racehorses.

BACKGROUND: Suspensory ligament branch injuries are common in horses. Most of these injuries are grouped together and considered as a single pathologic entity. OBJECTIVES: To report a specific injury of the abaxial margin of the suspensory ligament branches and to report its surgical management and outcome. STUDY DESIGN: Retrospective case series. METHODS: All horses with suspensory ligament branch injuries over a 9-year period (2007-2015) were identified. Horses with injuries which, on ultrasonographic examination, appeared to have defects in the abaxial margin of the suspensory ligament branch, that were subsequently confirmed during surgery were selected. RESULTS: Twenty-nine cases fulfilled the inclusion criteria with a specific lesion location on the abaxial margin of the suspensory ligament branch. Nineteen horses raced successfully after surgery, nine returned to training but failed to race and one was lost to follow-up. MAIN LIMITATIONS: The absence of a comparable population of non-surgically managed horses in this study means that the contribution of removing torn tissue cannot confidently be assessed. CONCLUSIONS: The location and morphology of injuries described in this study is consistent, which suggests aetiopathogenic commonality. This case series suggests this type of injury has an identity of its own, differs from other types of suspensory ligament branch injuries and represents a previously undescribed subgroup.

Short frontal plane fractures involving the dorsoproximal articular surface of the proximal phalanx: Description of the injury and a technique for repair.

BACKGROUND: Chip fractures of the dorsoproximal articular margin of the proximal phalanx are common injuries in racehorses. Large fractures can extend distal to the joint capsule insertion and have been described as dorsal frontal fractures. OBJECTIVES: To report the location and morphology of short frontal plane fractures involving the dorsoproximal articular surface of the proximal phalanx and describe a technique for repair under arthroscopic and radiographic guidance. STUDY DESIGN: Single centre retrospective case study. METHODS: Case records of horses with frontal plane fractures restricted to the dorsoproximal epiphysis and metaphysis of the proximal phalanx referred to Newmarket Equine Hospital were retrieved, images reviewed and lesion morphology described. A technique for repair and the results obtained are reported. RESULTS: A total of 22 fractures in 21 horses commencing at the proximal articular surface exited the dorsal cortex of the proximal phalanx distal to the metacarpophalangeal/metatarsophalangeal joint capsule in 17 hind- and five forelimbs. All were in Thoroughbred racehorses. In 16 cases these were acute racing or training injuries; 20 fractures were medial, one lateral and one was midline. All were repaired with a single lag screw using arthroscopic and radiographically determined landmarks. A total of 16 horses raced after surgery with performance data similar to their preinjury levels. MAIN LIMITATIONS: The study demonstrates substantial morphological similarities between individual lesions supporting a common pathophysiology, but does not identify precise causation. There are no cases managed differently that might permit assessment of the comparative efficacy of the treatment described. CONCLUSIONS: Short frontal plane fractures involving the dorsoproximal margin of the proximal phalanx that exit the bone distal to the metacarpophalangeal/metatarsophalangeal joint capsule have substantial morphological similarities, are amenable to minimally invasive repair and carry a good prognosis for return to training and racing.

Frequency distribution of osteochondral fragmentation of the dorsoproximal articular surface of the proximal phalanx in racing Thoroughbreds in the UK.

BACKGROUND: Osteochondral fragmentation of the dorsoproximal margin of the proximal phalanx is commonly recognised in racing Thoroughbreds. Frequency distribution has been documented in racing Thoroughbreds and Quarter Horses in the USA and in European Warmbloods but no data have been published from the UK. Concurrent intra-articular soft tissue lesions and radiographic accuracy of fragment distribution in racing Thoroughbreds have not previously been reported. OBJECTIVES: To document frequency distribution of dorsoproximal fragmentation of the proximal phalanx in a UK population of racing Thoroughbreds and to compare this with published data. To document concurrent intra-articular lesions identified arthroscopically and radiographic accuracy of fragment distribution. STUDY DESIGN: A retrospective single centre-based, observational study. METHODS: Surgical reports and radiographs of all racing Thoroughbreds that underwent arthroscopic surgery for removal of fragmentation from the dorsoproximal margin of the proximal phalanx at Newmarket Equine Hospital between 2011 and 2015 were reviewed. RESULTS: Two hundred and forty-two (85.8%) horses were in or being prepared for flat racing. Osteochondral fragmentation of the dorsoproximal aspect of the proximal phalanx was present in 428 fetlock joints of 282 horses, consisting of 194 (45.3%) left and 188 (43.9%) right metacarpophalangeal joints, and 20 (4.7%) left and 26 (6.1%) right metatarsophalangeal joints. Fragmentation was located dorsomedially in 316 (73.8%), dorsolaterally in 32 (7.5%) and biaxially in 80 (18.7%) joints. Concurrent soft tissue lesions were identified in 168 (39.3%) joints. Radiographic evidence of fragmentation was visible in 320 joints (74.8%). MAIN LIMITATIONS: Limited numbers preclude conclusions with respect to yearlings and horses in jump race training. CONCLUSION: Dorsoproximal fragmentation of the proximal phalanx occurred most frequently medially and in the forelimbs. Sidedness was not demonstrated. Although similar to previously reported data, variance in limb distribution is evident. Further research is required to determine whether concurrent intra-articular soft tissue lesions are aetiopathogenic or an additional result of the pathological changes leading to fragmentation. Fragmentation site was not always accurately identified radiographically. The Summary is available in Spanish - see Supporting information.

Endoscopic assessment and treatment of lesions of the deep digital flexor tendon in the navicular bursae of 20 lame horses.

REASONS FOR PERFORMING STUDY: Clinical lesions of the deep digital flexor tendon and navicular bone are being reported with increasing frequency. However, the role of direct visualisation by navicular bursoscopy in the diagnosis and management of such injuries has not been explored. HYPOTHESIS: Navicular bursoscopy: 1) corroborates information obtained from other, noninvasive imaging modalities; 2) allows direct visualisation of lesions unidentified by other diagnostic modalities; 3) provides further information on morphology of lesions; and 4) permits minimally invasive surgical access to lesions. METHODS: The case records of all horses that underwent diagnostic navicular bursoscopy for the investigation of lameness admitted to 2 referral clinics (the Royal Veterinary College and Reynolds House Referrals) were evaluated retrospectively. Follow-up information was obtained by telephone questionnaire. RESULTS: Twenty-three bursae were examined endoscopically in 20 horses. Tears of the deep digital flexor tendon were seen in all horses (22 bursae). In 8 bursae, cartilage lesions were also present and in one bursa this was the only abnormal finding. Computed tomography and low field magnetic resonance imaging predicted tendon lesions in most cases, but failed to identify cartilage damage. Greater than 6 month follow-up information was available for 15 animals of which 11 were sound and 9 had returned to preoperative levels of performance. CONCLUSION: Lameness localised to the foot may result from tears of the deep digital flexor tendon and/or navicular fibrocartilage loss. Navicular bursoscopy allows comprehensive evaluation of these changes and also permits appropriate lesion management. POTENTIAL RELEVANCE: The diagnostic information obtained from and therapeutic options offered by bursoscopy justify its use in horses with clinical findings localising lameness to the navicular bursa.

Slab fractures of the third tarsal bone: Minimally invasive repair using a single 3.5 mm cortex screw placed in lag fashion in 17 Thoroughbred racehorses.

REASONS FOR PERFORMING THE STUDY: A technique for minimally invasive repair of slab fractures of the third tarsal bone has not previously been reported. Results of third tarsal bone slab fracture repair in Thoroughbred racehorses are lacking. OBJECTIVES: To report the outcomes of repair of uniplanar frontal slab factures of the third tarsal bone using a single 3.5 mm cortex screw in lag fashion. STUDY DESIGN: Retrospective case series. METHODS: Case records of horses that had undergone this procedure were reviewed. RESULTS: Seventeen horses underwent surgery. Eighteen percent of cases had wedge shaped third tarsal bones. A point midway between the long and lateral digital extensor tendons and centrodistal and tarsometatarsal joints created a suitable entry site for implants. The fracture location, configuration and curvature of the third tarsal bone and associated joints requires a dorsolateral proximal-plantaromedial distal trajectory for the screw, which was determined by preplaced needles. There were no complications and fractures healed in all cases at 4-6 months post surgery. Seventy-nine percent of horses returned to racing and, at the time of reporting, 3 are in post operative rehabilitation programmes. CONCLUSION: The technique reported provides a safe, appropriate and repeatable means of repairing slab fractures of the third tarsal bone. Surgical repair is a viable alternative to conservative management.

Parasagittal fractures of the proximal phalanx in Thoroughbred racehorses in the UK: Outcome of repaired fractures in 113 cases (2007-2011).

BACKGROUND: Thirty years have elapsed since the last published review of outcome following fracture of the proximal phalanx in Thoroughbred racehorses in the UK and contemporary results are needed to be able to advise of expected outcome. OBJECTIVES: Collect and analyse outcome data following repair of fractures of the proximal phalanx in Thoroughbred racehorses in the UK. STUDY DESIGN: Retrospective case series. METHODS: Case records of all Thoroughbred racehorses admitted to Newmarket Equine Hospital for evaluation of a parasagittal fracture of the proximal phalanx during a 5 years period were reviewed. Follow-up data regarding racing careers was collected for horses that underwent repair. Following exclusion of outliers, cases with incomplete data sets and comminuted fractures, mixed effect logistic regression was used to identify variables affecting returning to racing and odds ratios and confidence intervals calculated. RESULTS: Of 113 repaired cases, fracture configurations included short incomplete parasagittal (n = 12), long incomplete parasagittal (n = 86), complete parasagittal (n = 12) and comminuted (n = 3). A total of 54 (48%) cases raced after surgery. Horses that fractured at 2 years of age had increased odds of racing following surgery than those older than 2 years of age (OR 1.34; 95% CI 1.13-1.59, P = 0.002). Horses sustaining short incomplete parasagittal fractures had increased odds of racing following surgery compared with those with complete parasagittal fractures (OR 2.62; 95% CI 1.36-5.07, P = 0.006). No horses with comminuted fractures returned to racing. MAIN LIMITATIONS: Data are relevant only to Thoroughbred racehorses in the UK. CONCLUSIONS: Approximately half of the cases in this series raced following surgical repair. More 2-year-old horses raced following surgery, but this likely reflects horses, specifically older horses, passing out of training from unrelated factors. Fracture configuration affects odds of racing, which is relevant to owners when deciding on treatment.

Development of Real-Time RT-PCR Assays for Detection and Typing of Epizootic Haemorrhagic Disease Virus.

Epizootic haemorrhagic disease virus (EHDV) is an emerging arboviral pathogen of wild and domestic ruminants worldwide. It is closely related to bluetongue virus (BTV) and is transmitted by adult females of competent Culicoides vector species. The EHDV genome consists of ten linear double-stranded (ds)RNA segments, encoding five non-structural and seven structural proteins. Genome-segment reassortment contributes to a high level of genetic variation in individual virus strains, particularly in the areas where multiple and distinct virus lineages co-circulate. In spite of the relatively close relationship between BTV and EHDV herd-immunity to BTV does not appear to protect against the introduction and infection of animals by EHDV. Although EHDV can cause up to 80% morbidity in affected animals, vaccination with the homologous EHDV serotype is protective. Outer-capsid protein VP2, encoded by Seg-2, is the most variable of the EHDV proteins and determines both the specificity of reactions with neutralizing antibodies and consequently the identity of the eight EHDV serotypes. In contrast, VP6 (the viral helicase), encoded by Seg-9, is highly conserved, representing a virus species/serogroup-specific antigen. We report the development and evaluation of quantitative (q)RT-PCR assays targeting EHDV Seg-9 that can detect all EHDV strains (regardless of geographic origin/topotype/serotype), as well as type-specific assays targeting Seg-2 of the eight EHDV serotypes. The assays were evaluated using orbivirus isolates from the 'Orbivirus reference collection' (ORC) at The Pirbright Institute and were shown to be EHDV pan-reactive or type-specific. They can be used for rapid, sensitive and reliable detection and identification (typing) of EHDV RNA from infected blood, tissue samples, homogenized Culicoides, or tissue culture supernatant. None of the assays detected RNA from closely related but heterologous orbiviruses, or from uninfected host animals or cell cultures. The techniques presented could be used for both surveillance and vaccine matching (serotype identification) as part of control strategies for incursions in wild and domestic animal species.

Arthroscopic diagnosis and treatment of intra-articular insertional injuries of the suspensory ligament branches in 18 horses.

REASONS FOR PERFORMING STUDY: Clinical association between the branches of insertion of the suspensory ligament (SL) and metacarpophalangeal (MCP) and metatarsophalangeal (MTP) joints has been reported. However, there has been no assessment of the lengths of the SL branches which are subsynovial with respect to the joints or reports of involvement of the MCP/MTP joints in injuries of the SL branches. OBJECTIVES: To establish proportions of SL branches subsynovial with respect to the MCP/MTP joints and report clinical and arthroscopic findings in horses with desmitis of SL branches identified as having an articular component to the lesion. HYPOTHESIS: Arthroscopic surgery enables identification and potential treatment of intra-articular injuries of SL branches. METHODS: Twelve forelimbs and 13 hindlimbs were dissected and the total and subsynovial lengths of the SL branches recorded. Case records of horses with intra-articular injuries of the SL branches were reviewed and 18 animals identified. Diagnostic information and arthroscopic findings were recorded and results of treatment determined by telephone follow-up. RESULTS: Of SL branches, 28.45% in the forelimb and 29.56% in the hindlimb were subsynovial to the MCP and MTP joints. All animals with intra-articular lesions of the SL branch were lame and had distension of the affected MCP/MTP joint. In 16 horses (17/22 branches), there was palpable thickening of the affected SL branch. Disrupted infrastructure was evident ultrasonographically in 15/17 branches and involvement of the dorsal articular surface of the ligament was predicted in 12/17 branches. Following arthroscopic intervention, 13 horses returned to work at a level equal to or greater than that achieved prior to injury and 2 returned to work at a lower level. Three horses incurred separate injuries and were retired or subjected to euthanasia. CONCLUSIONS: Articular involvement should be considered in animals with injuries of an SL branch and concurrent distension of the MCP/MTP joint. Arthroscopy is necessary to identify such lesions confidently and to direct case management. POTENTIAL RELEVANCE: Arthroscopy of the MCP/MTP joints can make a positive contribution to the assessment and management of some SL branch injuries.

Noninfected tenosynovitis of the digital flexor tendon sheath: a retrospective analysis of 76 cases.

REASONS FOR PERFORMING STUDY: Until recently, the pathogenesis of noninfected tenosynovitis of the digital flexor tendon sheath (DFTS) has been considered obscure. With the advent of tenoscopy some inciting causes have been described, but to date few cases with a precise diagnosis have been reported. HYPOTHESIS: Tenoscopic surgery enables accurate diagnosis and facilitates treatment of noninfected tenosynovitis of the DFTS. METHODS: The case records of all horses with noninfected tenosynovitis of the DFTS admitted to a referral clinic over a 7-year period were evaluated retrospectively. Follow-up information was obtained by telephone questionnaire. RESULTS: A total of 76 horses were referred; all were evaluated tenoscopically and 11 of these subsequently were explored by open surgical techniques. The most common diagnoses were marginal tears of the deep digital flexor tendon (DDFT) (n = 44) and tears of the manica flexoria (MF) (n = 23). Greater than 6 months' follow-up information was available for 61 animals, of which 68% were sound and 54% returned to preoperative levels of performance. Sheath distension was eliminated in 33% and improved in 69% of horses. Marginal tears of the DDFT, marked preoperative distension and open surgical repair of deep digital flexor lesions were associated with reduced levels of post operative performance: Marginal tears were associated with post operative lameness and long tears with a reduced performance level compared with short tears. Marginal tears of the deep digital flexor tendon, marked preoperative distension and increasing duration of clinical signs also were associated with lack of improvement in distension following surgery. CONCLUSION: Tenosynovitis of the DFTS may result from tears in the deep or superficial digital flexor tendons, manica flexoria or other structures with synovial communication. To date, these can be identified confidently only by tenoscopy, which also permits appropriate lesion management. POTENTIAL RELEVANCE: The diagnostic information obtained from and therapeutic options offered by tenoscopy justify its early use in cases of noninfected tenosynovitis of the DFTS.

Microvascular effects of corticotropin-releasing hormone in human skin vary in relation to estrogen concentration during the menstrual cycle.

Females have a significantly greater life expectancy than males, which in part may be due to the cardio-protective effects of the female sex hormone, estrogen, on vascular function. However, the sex-specific mechanisms contributing to these differences are complex and not fully understood. Previously we have reported that corticotropin-releasing hormone (CRH) has potent dilator effects in the female skin circulation via mast cell degranulation. Furthermore the dilator response to CRH was more enhanced in females than in age-matched males, suggesting that estrogens may be involved. In this study we examined whether CRH-induced dilation and endothelial cell-dependent dilation in the skin circulation of pre-menopausal females were associated with changes in estrogen during the menstrual cycle. CRH-induced dilation (1 nM) was enhanced in the presence of high circulating concentrations of estrogen and a positive correlation was identified between CRH-induced dilation and plasma estrogen concentrations. Endothelial cell-dependent dilation was examined using acetylcholine. Acetylcholine-induced dilation (1 nM) was not correlated with circulating concentrations of estrogen. These data suggest the variation in CRH-induced dilation in the skin microvasculature during the menstrual cycle may be due to estrogenic effects on mast cell function and not due to direct changes in endothelial cell function.

Peri-anaesthetic complications in an equine referral hospital: Risk factors for post anaesthetic colic.

REASONS FOR PERFORMING STUDY: Peri-anaesthetic complications are relatively common in equine patients and further investigations are warranted to identify manageable risk factors. OBJECTIVES: To report morbidity and mortality rates and identify associated risk factors for horses undergoing general anaesthesia, within a predominantly racing Thoroughbred (TB) population. STUDY DESIGN: Single centre retrospective observational study. METHODS: Anaesthetic and case records of all horses ≥12 months old undergoing general anaesthesia at Newmarket Equine Hospital between August 2010 and April 2012 were analysed, excluding emergency abdominal/dystocia procedures or traumatology cases with cardiovascular compromise. Mortality and morbidity rates were calculated and described. Uni- and multivariable analyses were used to investigate the relationship between the principal complication, post anaesthetic colic (PAC) and risk factors. RESULTS: A total of 1067 anaesthetic records of 1021 horses were included in the study; of these, 702 horses (65.8%) were TB, 169 (15.8%) developed a complication within 7 days of general anaesthesia and 10 (0.94%) died as a result. The most prevalent morbidity was PAC, 111 horses (10.5%) developed colic within 7 days of general anaesthesia. Thoroughbred horses (odds ratio [OR] 2.93, 95% confidence interval [CI] 1.73-4.96) and horses receiving sodium benzylpenicillin (NaBP) (OR 2.77, 95% CI 1.69-4.50) were at increased risk of PAC. CONCLUSIONS: Thoroughbred racehorses were identified as at increased risk of PAC in this study and might benefit from more critical evaluation of post anaesthetic gastrointestinal function. An alternative to the administration of NaBP for prophylactic antimicrobial therapy needs to be further investigated if its role in PAC is confirmed by other studies.