Testing the concept of virally vectored immunosterilisation for the control of wild rabbit and fox populations in Australia

SUMMARY: Virally vectored immunosterilisation is a concept whereby a gene encoding an antigen from an animal's reproductive system is inserted into a virus and, during infection, stimulates the formation of antibodies to that antigen such that the animal is rendered infertile. There is good evidence that certain proteins from sperm or egg when introduced parenterally will induce infertility. This paper summarises the work of the Cooperative Research Centre for the Biological Control of Vertebrate Pest Populations and reviews progress toward the isolation of the genes for gamete antigens from rabbits and foxes and their introduction into suitable viral vectors as a means of control of these pests in Australia     

Microanatomy of the Canine Claw

Abstract— The histologic appearance of the canine claw was evaluated in twenty dogs of various breeds. Sagittal and horizontal cross sections of the claw were obtained, fixed, decalcified and stained with hematoxylin and eosin. Sections were evaluated and are described herein. Among notable findings were few to numerous intranuclear vacuoles found predominantly in the cells of the stratum spinosum, especially in the dorsal and ventral matrix. These vacuoles displaced the chromatin to the periphery. There was epidermal ridge formation in the angle of the dorsal fold. In several specimens there were clefts at the dermoepidermal junction present most commonly in the dorsal matrix. The previously reported lack of a granular layer in the epithelium forming the claw was confirmed. Résumé— L'aspect histologique de l'ongle du chien a étéétudié chez 20 chiens de races différentes. Des coupes horizontales et sagitales ont été faites, fixées, décalcifiées et colorées à l'hémalin-éosine. Parmi les observations les plus significatives on note de nombreuses vacuoles intranucléaires principalement dans les cellule de la couche épineuse et plus particulièrement au niveau dorsal et ventral de la matrice. Ces vacuoles déplacement la chromatine en périphérie. Il y avait des crêtes épidermíques au niveau du pli dorsal. Dans plusieurs specimens il existait des disjonction dermoépidermiques, principalement au niveu de la matrice dorsale. L'absence de couche granuleuse dans l'épithélium formant l'ongleprécédemment décrite a été confirmée. Zusammenfassung— Bei zwanzig Hunden verschiedener Rassen wurde der histologische Aufbau der Hundekralle untersucht. Es wurden sagittale und horizontale Schnitte angefertigt, fixiert, entkalkt und mit Hämatoxylin und Eosin gefärbt. Die Schnitte wurden ausgewertet und beschrieben. Beachtenswerte Befunde sind wenige bis zahlreiche intranukleäre Vakoulen, die vorwiegend in den Zellen des Stratum spinosum, speziell in denen der dorsalen und ventralen Matrix, gefunden wurden. Die Vakuolen drängten das Chromatin an die Peripherie. Im Winkel der dorsalen Falte war eine epidermale Kammbildung zu beobachten. Bei einigen Proben waren spalten in der dermoepidermalen Verbindung vorhanden, am häufigsten in der dorsalen Matrix. Das schon früher bekannte Fehlen einer granulären Schicht im Epithel, das die Kralle bildet, Wurde bestätigt. Resumen En este artículo se estudia la apariencia histológica de la uña canina en veinte perros de diferentes razas. En un principio se obtuvieron secciones sagitales y horizontales, luego se fijaron, decalcificaron, y tiñeron con hematosilina-eosina. Las secciones fueron evaluadas y se describiran a continuación. Entre un considerable número de hallazgos, se demostró la presencia dede un número de vacuolas intranucleares predominantemente en las células del estrato espinoso, y especialmente en la matríz dorsal y ventral. Estas vacuolas se encontraban desplazando la cromatina hacia la periferia de la célula. También se observó la presencia de la formación de una cresta epidérmica en el ángulo del pliegue dorsal. En algunos de los especimenes se vieron indentaciones a nivel de la frontera dermo-epidérmica, mas frecuentemente en la matriz dorsal. También se confirmo la ausencia de de capa granular en el epitelio de la uña.     

Canine granular cell tumour (myoblastoma): a report of four cases and review of the literature

Four cases of canine granular cell tumour (myoblastoma) were diagnosed at the Washington Animal Disease Diagnostic Laboratory between 1977 and 1981. Two of the tumours occurred in the tongue, one in the lip and one in the larynx. Three cell types were found in the tumours. Granular cells, with abundant periodic acid-Schiff (PAS)-positive cytoplasmic granules, were most numerous. Interstitial cells resembled fibroblasts and were often adjacent to collagen fibrils. Angulate body cells contained PAS-positive, ovoid cytoplasmic inclusions composed of microtubular subunits. Review of these and reported cases indicates no breed or sex predisposition for this rare tumour. The tongue is the most common site and all but one tumour have occurred in or adjacent to the oral cavity. There have been no reports of recurrence or metastasis of granular cell tumours except the recurrence of a disputed case in the subcutis of a dog.     

Evaluation of Cervical Spinal Fusion as a Treatment in the Equine "Wobbler" Syndrome

Cervical vertebral interbody fusion was performed on 30 horses affected with cervical vertebral malformation (CVM) or "wobbles" to assess the efficacy of the surgery in either preventing progression of or reversing the neurologic deficit induced by the syndrome. Evaluation of each horse prior to surgery included clinical, radiographic, neurologic, and laboratory examination. Subjects ranged from 3 months to 8 years of age, and included 22 males and 8 females of various breeds. Three normal horses were included as controls. The Cloward method of cervical fusion was used to achieve stabilization at the affected vertebral articulation. Horses were reexamined 3 months after surgery. Clinical improvement was seen in 90% (27 of 30) of the cases. Four horses were returned to training, which had been interrupted by onset of symptoms. Seven were returned to owners as breeding animals. Twelve horses were kept for long-term studies. Seven horses were sacrificed to examine the surgical site. In 6 of the 7 horses on which necropsy was performed, the most severe histologic lesion in the spinal cord could be predicted from lesions seen radiographically. The spinal cords of control animals were normal. Osseous fusion was dependent on the completeness of removal of disc fibrocartilage during surgery. We conclude that clinical improvement in some horses affected with CVM can be achieved by cervical fusion.     

MORPHOLOGY OF THE CAUDAL FOSSA IN CAVALIER KING CHARLES SPANIELS

Chiari malformations and syringohydromyelia are an important disease complex in Cavalier King Charles Spaniels. Although abnormalities in caudal fossa morphology are considered major contributors to the development of this disease, limited information exists on the range of morphologies in Cavalier King Charles Spaniels and on the relationship of these to clinically evident disease. Sixty-four Cavalier King Charles Spaniels were studied. Each underwent a neurologic examination and magnetic resonance imaging of the cervical spine and brain. T2-weighted sagittal images were used to determine both the morphologic characteristics and volume of the caudal fossa in each dog. This volume was also analyzed as a percentage of total cranial cavity volume. Each attribute was correlated with neurological grade and presence of syringohydromyelia. Fifteen dogs had neurologic signs, and 59 had morphologic abnormalities of the craniocervical junction. While 27 dogs had syringohydromyelia, 13 of these were clinically normal. Cerebellar herniation and occipital dysplasia were common findings but were not associated with syringohydromyelia. Dorsal compressive lesions were noted at the first and second cervical vertebral junction. Factors associated with the presence of neurologic signs included syringohydromyelia and the ratio of caudal fossa/total cranial cavity volume; dogs with signs had significantly larger syringohydromyelia than asymptomatic dogs. Caudal fossa size was not associated with syringohydromyelia. A positive association was identified between foramen magnum size and length of cerebellar herniation. The prevalence of craniocervical junction abnormalities is high in Cavalier King Charles Spaniels. While several factors are associated with neurologic signs, occipital hypoplasia appears to be the most important factor.     

IMPROVED IDENTIFICATION OF THE PALMAR FIBROCARTILAGE OF THE NAVICULAR BONE WITH SALINE MAGNETIC RESONANCE BURSOGRAPHY

Fibrocartilage degeneration is the earliest pathologic finding in navicular disease but remains difficult to detect, even with magnetic resonance (MR) imaging. We hypothesized that injection of the navicular bursa with saline would improve accuracy of MR imaging evaluation of palmar fibrocartilage. Thoracic limbs were collected from 11 horses within 6 h of death. Imaging was performed with a 1.5 T magnet using sagittal 2D proton density and transverse 3D FLASH sequences with fat saturation. For the purpose of determining sensitivity and specificity of the MR images, fibrocartilage was classified as normal or abnormal, based on combination of the findings of gross and microscopic pathology. Thickness of fibrocartilage was measured on histologic sections and corresponding transverse FLASH MR images before and after injection of saline. A paired Student's t- test was used for comparison of measurements. Partial thickness fibrocartilage loss was present in 6 of 22 limbs. Sensitivity of precontrast MR images for detection of lesions was 100% while specificity was 6%. Saline MR arthrography resulted in both sensitivity and specificity of 100% based on consensus review. Mean histologic fibrocartilage thickness was 0.75±0.12 mm. Mean fibrocartilage thickness on precontrast transverse FLASH images was 0.93±0.065 and 0.73±0.09 mm on postsaline images. The histologic cartilage thickness was signficantly different from that in precontrast images ( P <0.001) but not in images acquired after saline injection ( P =0.716). Based on our results, and using pulse sequences as described herein, navicular fibrocartilage can only be evaluated reliably for the presence of partial thickness lesions after intrabursal injection of saline.