Magnetic Resonance Imaging of the Dorsal Proximal Synovial Plica of the Equine Metacarpo‐/Metatarsophalangeal Joint

A synovial plica is present at the dorsoproximal aspect of the fetlock joint. The objective of this study was to describe the location of the synovial plica during induced hyperextension using Magnetic Resonance Imaging. For this study 20 cadaver limbs from five Warmblood horses were used. Measurements were made of the dorsal; palmar/plantar length and the thickness of the plica with the joint in a normal position. During induced hyperextension of the joint, the position of the plica was described; the dorsal angle of extension and angle of contact between the proximal phalanx (P1) and the condyle were measured. The dorsal length differed between front/hind limbs and between the medial/lateral aspect of the joint. The angle of contact between P1 and condyle differed between front/hind limbs; between the lateral and medial aspect of the joint and between different positions of the plica. Four different positions of the plica were observed: shortened with the tip curved towards palmar/plantar; projecting distally; projecting towards dorsal and projecting distally with the tip interposed between P1 and the condyle. During induced hyperextension, a close relation is present between the synovial plica, P1 and the condyle with a variable position of the plica; which is suggestive for a contact interface between P1 and the metacarpal/metatarsal bone. However the plica does not seem to act consistently as a cushioning surface.     

Low‐Field Magnetic Resonance Imaging and Multislice Computed Tomography for the Detection of Cervical Syringomyelia in Dogs

Background

Syringomyelia (SM) is defined as the presence of fluid‐containing cavities within the parenchyma of the spinal cord. Sagittal magnetic resonance (MR) images have been described as the preferred technique for visualizing SM in dogs and humans.

Objective

To investigate whether computed tomography (CT) can be used to diagnose SM.

Animals

Thirty‐two client‐owned dogs referred for investigation of the cervical spine on magnetic resonance imaging (MRI) and CT.

Methods

Two reviewers retrospectively analyzed sagittal and transverse T1‐weighted spin echo (T1WSE) MR images and CT images from each dog for the presence of SM and, if SM was present, the width (mm, syrinx width [SW]) was measured. The results were analyzed statistically.

Results

For the presence of SM there was a moderate interobserver agreement for MR (81%, κ = 0.54) and almost perfect agreement for CT (94%, κ = 0.87). There was a moderate intramodality agreement for both observers (observer 1 81%, κ = 0.59; observer 2 81%, κ = 0.57). For measurement of SW the repeatability was the best on the midsagittal T1WSE images (95% repeatability coefficient <0.52 mm) and the reproducibility was the best on midsagittal images in both modalities (95% limits of agreement −0.55–0.45; P = 0.002).

Conclusion and Clinical Importance

Both techniques can be used to detect SM. Midsagittal MR and CT images are best used for measuring SW. Computed tomography can be used as a diagnostic tool for SM when MRI is not available, but CT cannot replace MRI as the standard screening technique for the detection of SM in Cavalier King Charles Spaniel for breeding purposes.     

Radiography,Computed Tomography and Magnetic Resonance Imaging of Craniofacial Structures in Pig

The pig has recently become popular as a large animal experimental model in many fields of biomedical research. The aim of this study is to evaluate the basic anatomical structures in the head region of the pig to lay the groundwork for its practical clinical usage or pre‐clinical research in the future. We used three different diagnostic imaging methods: radiography, computed tomography (CT) and magnetic resonance imaging (MRI). The analysis showed that radiographic imaging is suitable only for general evaluation of the facial area of the pig skull. CT images showed excellent spatial definition of bony structures of the whole craniofacial area, and MRI images revealed fine soft tissue details. Radiography is preferentially suited to general assessment of bone structures of the facial skeleton; however, the thick layer of adipose tissue in the craniofacial region of the pig makes the imaging of some parts difficult or even impossible. CT is useful for revealing morphological details of mineralized tissues, whereas MRI is more suitable for soft tissue analysis and the detection of subtle pathologic changes in both bone and soft tissues. Therefore, before using pigs as an experimental model in craniofacial research, it is necessary to evaluate the suitability and disadvantages of potential imaging methods and how appropriate they are for accurate visualization of desired structures.     

Collagen,glycosaminoglycans and matrix metalloproteinase‐2 and metalloproteinase‐9 in the cervix of the ewe during prepubertal development

The tortuous nature of the ovine cervix restricts the transcervical passage of the cannula, and many studies have aimed to understand the endocrine mechanism of the remodelling of cervical tissue in adult ewe. However, little is known about the remodelling of the cervical tissue during the prepubertal development of the lambs. To obtain histochemical and biochemical evidence about the nature of the prepubertal development of the cervix of the ewe, cervices of Corriedale lambs obtained at 0, 1, 2, 4, 6 and 8 months of age (n = 5 to 6 in each) were processed. Neutral and acidic glycosaminoglycans (by PAS‐Alcian stain) were weakly in the cervical stroma and not shown change during the development, whereas the percentage volume of fibrillar collagen (by van Gieson stain) increases throughout the experimental period in the superficial fold stroma and deep wall stroma (p < 0.05). The relative cervical weight (g/kg of body weight) and the collagen concentration (by spectrophotometry, mg/mg wet tissue) showed an early decreasing phase from months 0 to 4 and a later increasing phase from months 4 to 8 (p < 0.05). The latent form of matrix metalloproteinase‐2 (MMP‐2) detected by gelatin zymography (ng/mg protein) decreased from months 0 to 2 and increased from months 4 to 8, whereas the activated form decreased from months 0 to 2, remained low until month 6 and then recovered on month 8 (p < 0.0001). Data suggest that the relative cervical weight biphasic pattern during the development is related to MMP‐2‐dependent changes in the collagen content.     

Detection of Enterohemorrhagic Escherichia coli in Meat Foods using DNA Probes,Enzyme‐Linked Immunosorbent Assay and Polymerase Chain Reaction

Enterohemorrhagic Escherichia coli (EHEC) is an important cause of diarrhoea with blood and haemolytic uremic syndrome (HUS) in children and elderly people. Infections with EHEC are a world‐wide public health problem, related to consumption of contaminated ground beef. The aim of this study was to establish whether different meat foods sold in Santiago, Chile pose an infection risk by EHEC and to evaluate three different diagnostic techniques in foods, to determine which is most applicable for use in Chile. A parallel analysis was performed on 64 samples of meat foods (23 refrigerated ground meat, 23 refrigerated long pork sausages and 18 frozen hamburgers) sold in Santiago, Chile using DNA probes, enzyme‐linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR). Twenty‐four samples (24 of 64=37.5 %) were positive by DNA probes, ELISA or PCR. The positive and negative predictive values, sensitivity and specificity of ELISA were 26.7, 81.6, 30.8 and 78.4 %, respectively. The positive and negative predictive values, sensitivity and specificity of PCR were 91.7, 96.2, 84.6 and 98 %, respectively. The EHEC serogroups most frequently isolated were O158, O157, O119, O125 and O114. These results show that, although molecular techniques such as enzyme immunoassays are useful for EHEC detection in meat foods, PCR has advantages in terms of sensitivity, specificity, cost and ease of implementation in Chile.     

The Effect of Long‐term In Vivo Culture in Bovine Oviduct and Uterus on the Development and Cryo‐tolerance of In Vitro Produced Bovine Embryos

The objective of this study was to compare the embryo production and quality carried out entirely in vitro or partly in vitro combined with short‐ vs long‐term in vivo culture using the homologous cattle oviduct. The IVM oocytes were in vitro fertilized and cultured for 7 and 8 days (IVP‐Group), or after IVF and 2–3 days of IVC, 4–8 cell stage embryos were endoscopically transferred into oviducts of synchronized heifers (In Vivo‐Group) or IVM oocytes were co‐incubated with spermatozoa for 3–4 h and transferred into the oviducts of synchronized heifers (GIFT‐Group). Embryos of the In Vivo‐Group and the GIFT‐Group were recovered on day 7 from the oviducts and uterine horns. Embryos of all groups were either cryopreserved at day 7 (day 7 blastocysts) or cultured in vitro in CR1aa‐medium supplemented with 5% ECS for further 24 h and cryopreserved (day 8 blastocysts). The total blastocyst yield found in the in vivo cultured groups was similar to the results of the IVP‐Group. But the appearance of blastocysts was dependent on the duration of in vivo culture. The more time the embryos spent in the in vivo environment, the more blastocysts appeared at day 8. The quality of produced blastocysts assessed by cryo‐survival was also correlated to the culture conditions; the in vivo cultured embryos showed higher cryo‐tolerance. However, the duration of in vivo culture crucially influenced the cryo‐tolerance of produced blastocysts. It is concluded that tubal access is a promising tool to provide a further basis for studying embryo sensitivity to environmental changes.     

Sero‐epidemiology of Canine Leptospirosis in Trinidad: Serovars,Implications for Vaccination and Public Health

A sero‐epidemiological study on canine leptospirosis was conducted in house, stray, farm and hunting dogs, as well as in suspect cases of clinical canine leptospirosis. Serum samples were collected from apparently healthy (vaccinated and non‐vaccinated), house dogs. A questionnaire was administered to the owners to elicit information on risk factors for leptospirosis. The microscopic agglutination test was used to screen for leptospirosis using 17 international serovars. Reciprocal titres of between 100 and <800 were considered as evidence of past exposure while reciprocal titres of 800 or greater were classified as suggestive of acute/current infection. Of a total of 419 serum samples tested, 61 (14.6%) were seropositive for Leptospira agglutinins, 23 (5.5%) had mixed infections and 16 (3.8%) had current infection. Amongst 50 suspected cases of clinical leptospirosis, 24 (48.0%) were seropositive and only 13 (26.0%) had current infection compared with 10 (6.3%) and three (1.9%) of 160 apparently healthy house dogs respectively. The difference was statistically significant (P < 0.05; χ²). Twelve (25.5%) of 47 hunting dogs, 10 (20.4%) of 49 farm dogs and five (4.4%) of 113 stray dogs were seropositive (P < 0.05; χ²). Overall, a total of nine serovars were detected with serovars mankarso, icterohaemorrhagiae RGA, autumnalis and copenhageni being involved in 29 (47.5%), 20 (32.8%), 25 (41.0%) and 10 (16.4%) respectively in 61 seropositive dogs (P < 0.05; χ²). Serovar mankarso was most predominant in seropositive apparently healthy dogs, 37.8% (14/37), suspected clinical cases of leptospirosis, 62.5% (15/24) compared with serovar icterohaemorrhagiae with a frequency of 21.6% (8/37) and 50.0% (12/24), the difference being statistically significant (P < 0.05; χ²). Although all vaccines used for prevention of canine leptospirosis in the country contain serovars canicola and icterohaemorrhagiae, serovar mankarso was mostly associated with infection and disease and may be a good candidate for inclusion in the vaccine used locally. The public health risk posed to owners of dogs infected with Leptospira cannot be over‐emphasized considering the zoonotic nature of the disease.     

Magnetic Resonance Imaging Study of Adipose Tissues in the Head of a Common Dolphin (Delphinus delphis): Structure Identification and Influence of a Freezing–Thawing Cycle

Magnetic resonance imaging (MRI) was used to scan the head of a common dolphin (Delphinus delphis) in order to visualize the different adipose tissues involved in echolocation functioning and to precisely delineate their anatomical topology. MRI scans were performed on the head taken from a freshly stranded carcass and repeated after a 2‐week freezing time followed by thawing. The main fatty organs of the head, that is the melon, the mandibula bulba, the bursae cantantes, and their different connections with surrounding tissues were identified and labelled. The nasal sacs, other organs of echolocation, were also identified and labelled thanks to different MRI acquisitions. The shape, the location, the type of MRI signal of each organ and of their different connections were successfully analysed on all images, and then, the images of the head fresh or after thawing were compared. No impacts of the freezing/thawing cycle on the fatty tissues of the head were identified. Different parts were distinguished in the melon on the basis of the MRI signal emitted, corresponding most likely to the internal and external melon already identified by other analytical approaches, and linked to differences in lipid composition. MRI is shown here to be a useful tool to study the functional anatomy of the organs responsible for echolocation in odontocetes, with a particularly high level of precision.