MRI FEATURES OF METACARPO(TARSO)PHALANGEAL REGION LAMENESS IN 40 HORSES

Lameness originating from the metacarpo(tarso)phalangeal (MP) joint has a significant effect on the use and athletic competitiveness of a horse. The identification of the cause of lameness originating from the MP joint can be challenging, given the limitations of radiography, ultrasonography, and nuclear scintigraphy. Our purpose was to describe the injury types and incidence in magnetic resonance imaging (MRI) studies from 40 horses with lameness attributable to the MP joint region where it was not possible to reach a clinically plausible diagnosis using other imaging modalities. Horses were examined in a 1.5 T magnet (Siemens Medical Solutions) under general anesthesia. The frequency of occurrence of MR lesions was subchondral bone injury (19), straight or oblique distal sesamoidean desmitis (13), articular cartilage injury and osteoarthritis (eight), suspensory branch desmitis (seven), osteochondral fragmentation (seven), proximal sesamoid bone injury (seven), intersesamoidean desmitis (four), deep digital flexor tendonitis (four), collateral desmitis (three), superficial digital flexor tendonitis (two), enostosis‐like lesions of the proximal phalanx or MCIII (two), desmitis of the palmar annular ligament (one), desmitis of the proximal digital annular ligament (one), and dystrophic calcification of the lateral digital extensor tendon (one). Twenty‐five horses had multiple MR abnormalities. MRI provided information that was complementary to radiography, ultrasonography, and nuclear scintigraphy and that allowed for a comprehensive evaluation of all structures in the MP joint region and a diagnosis in all 40 horses.     

CLINICAL, MAGNETIC RESONANCE, AND SONOGRAPHIC IMAGING FINDINGS IN HORSES WITH PROXIMAL PLANTAR METATARSAL PAIN

Sonography is commonly used for diagnosis of desmopathy of the proximal part of the suspensory ligament in horses. However, magnetic resonance (MR) imaging has been stated to be superior for detecting disease and localizing lesions. In this retrospective study of 39 horses or 46 hind limbs with lameness due to proximal plantar metatarsal pain, the clinical and diagnostic findings are discussed and sonography and MR imaging compared for examination of the proximal part of the suspensory ligament. With MR imaging interpreted as the clinical gold standard, desmopathy of the proximal part of the suspensory ligament was diagnosed in 21 hind limbs, proximal plantar metatarsal pain of unknown cause in 12, an osseous injury at the origin of the suspensory ligament in four and a condition unrelated to the suspensory ligament in nine. Based on these findings, sonography had a sensitivity of 0.77 and 0.66 and specificity of 0.33 and 0.31 for diagnosing proximal suspensory desmopathy and for accurately localizing lesions, respectively. MR imaging changes consistent with proximal suspensory desmopathy were signal hyperintensities and an increase in cross-sectional area compared with the contralateral limb. Anesthesia of the deep branch of the lateral plantar nerve is not specific neither for proximal suspensory desmopathy, as conditions unrelated to the suspensory ligament were diagnosed, nor for diagnosis of proximal plantar metatarsal pain, as conditions outside the proximal plantar metatarsal region were also diagnosed.     

The Effect of Intradermal Injection of GM-CSF and TNF-α on the Accumulation of Dendritic Cells in Ovine Skin

Abstract— Intradermal recombinant ovine (rov) GM-CSF was associated with the accumulation over 5 DAys of MHC Class-II+ dendritic cells at the injection site, as well as increased numbers of neutrophils, eosinophils and lymphocytes when compared to control injection sites receiving heat-inactivated cytokines. Most of the dendritic cells were adjacent to the epidermis and dermal structures such as hair follicles, sweat glands and blood vessels. Fewer than 10% of the accumulating MHC Class-II+ dendritic cells expressed the CD1 antigen and none expressed detectable CD lib or CD lie antigens. They did not appear to be proliferating. Injection of rov TNF-α was associated with an increase in MHC Class-II+ dendritic cells that was significant only in the epidermis and only at 2 DAys following the first of four daily injections. Increased numbers of neutrophils and lymphocytes, but not eosinophils, were also recorded. Injection of rov TNF-α together with rov GM-CSF enhanced the accumulation of the MHC Class-II+, CD1+ subpopulation of dendritic cells compared to either cytokine alone. GM-CSF in particular is involved in an in vivo pathway supporting the accumulation of predominantly MHC Class-II+ CD1^- dendritic cells which are a minor population in unchallenged skin. Résumé— Des injections intradermiques de GM-CSF recombinant ovin sont associées à l'accumulation en 5 jours de cellules dendritiques MHC classe II(+) au site de l'injection, ainsi qu'à une augmentation du nombre de neutrophiles, éosinophiles et lymphocytes, comparativement à ce qui est observe aux points d'injection témoins qui ont reçu des cytokines inactivées par la chaleur. La plupart des cellules dentritiques sont adjacentes à l'épiderme, aux follicules pileux, aux glandes sudoripares et aux vaisseaux sanguins. Moins de 10% des cellules dendritiques MHC classe II(+) accumulées expriment l'antigène CD1 et aucune n'exprime les antigènes CD11b et CD11c. Elles ne semblent pas proliférer. L'injection de TNF alpha recombinant ovin est associée à une augmentation des cellules dendritiques MHC classe II(+) qui est significative seulement dans l'épiderme, et seulement 2 jours suivant la première des quatre injections. Une augmentation du nombre de neutrophiles et de lymphocytes, mais pas des éosinophiles est également notée. L'injection simultanée de TNF alpha recombinant ovin et de GM-CSF recombinant ovin favorise l'accumulation d'une sous population de cellules dendritiques MHC classe II(+), CD1(+), comparativement à ce qui est observé en utilisant les cytokines séparément. GM-CSF en particulier est in vivo à l'origine de l'accumulation de cellules dendritiques MHC classe II(+), CD1(—) qui forment une population mineure dans la peau. [Haig, D. M., Hutchison, G., Green, I., Sargan, D., Reid, H. W. The effect of intradermal injection of GM-CSF and TNF-α on the accumulation of dendritic cells in ovine skin (Effect de l'injection intradermique de GM-CSF et de TNF alpha sur l'accumulation de cellules dentritiques dans la peau du mouton).     

HOSPITAL, RADIOLOGY, AND PICTURE ARCHIVING AND COMMUNICATION SYSTEMS

Images generated during the course of patient evaluation and management are an integral part of the medical record and must be retained according to local regulations. Digital Imaging and Communications in Medicine (DICOM) makes it possible for images from many different imaging modalities to be distributed via a standard internet network to distant viewing workstations and a central archive in an almost seamless fashion. The DICOM standard is a truly universal standard for the dissemination of medical images. Picture Archive and Communication System (PACS) refers to the infrastructure that links modalities, workstations, the image archive, and the medical record information system into an integrated system, allowing for efficient electronic distribution and storage of medical images and access to medical record data. This paper discusses the important elements to a successful PACS implementation in a practice, including how it interacts with other practice computing systems.     

Simulation of juvenile sockeye salmon (Oncorhynchus nerka) migrations in the Strait of Georgia, British Columbia

Previous research has documented two main migratory routes of juvenile sockeye salmon (Oncorhynchus nerka) through the Strait of Georgia, British Columbia, Canada, and large interannual variability in marine survival rates of the Chilko Lake stock. Simulation models were used to explore the influence of surface currents on the migratory route of juvenile sockeye salmon (smolts) through the Strait of Georgia. We used a model of downstream migration to generate daily numbers of Chilko Lake sockeye salmon smolts entering the Strait of Georgia, based on daily counts of smolts leaving the rearing lake. A numerical hydrodynamic model (driven by surface wind, tide, and Fraser River discharge) hindcasted surface currents in the Strait of Georgia on a 2 km × 2 km grid. A smolt migration model simulated fish moving through the Strait with different compass-oriented migratory behaviours (i.e. swimming speed and directional orientation) within the time-varying surface advection field. Results showed that surface currents within the Strait of Georgia can affect the migratory route of sockeye salmon smolts in spite of their large size (8 cm). Wind is the forcing mechanism primarily responsible for determining which migratory route would be used. Under prevailing wind conditions (i.e. toward the north-west), most sockeye salmon smolts would use the eastern migratory route; however, relatively brief south-eastward wind events (lasting about 2 days) would force most smolts into the western migratory route. Given the heterogeneity of food for salmon within the Strait, we hypothesize that wind-driven variability in the annual proportion of smolts that use the western and eastern migratory routes in the Strait of Georgia affects early marine survival rates of Fraser River sockeye salmon.