IMAGING OF A SPINAL NEPHROBLASTOMA IN A DOG

An 8-month-old German Shepherd dog was presented for investigation of pelvic limb gait abnormality. Neurolocalization indicated a T3-L3 spinal cord lesion. The myelographic appearance was of an intramedullary lesion at T9/10, but upon subsequent magnetic resonance imaging it was determined that the mass was extramedullary. A diagnosis of nephroblastoma was made on histological examination. The imaging features of this rare tumor and the differentiation of intradural-extramedullary and intramedullary masses are discussed.     

The prevalence of Dirofilaria immitis in dogs in Sydney

Four hundred and four dogs from 9 pounds in Sydney were examined for circulating microfilariae and antigens of Dirofilaria immitis. One hundred of these were also examined post mortem for adult heartworms. The prevalence of infection in the 404 dogs as shown by serology was 11.4%, and 5.9% had circulating microfilariae of D immitis. Adult heartworms were present in 15 of 100 dogs. Dipetalonema reconditum microfilariae were present in 3.7% of dogs. Dirofilariosis is still a common and important parasite of dogs in the Sydney region and chemoprophylaxis is recommended.     

Effects of Short-term Hyper- and Hypoprolactinaemia on Hormones of the Pituitary, Gonad and -Thyroid Axis and on Semen Quality in Male Beagles

Effects of a short-term hyper- and hypoprolactinaemia on serum concentrations of LH, testosterone and semen quality in six male Beagles were investigated. Blood samples were collected at 3-day intervals for 12 weeks. The time span was divided into five 3-week periods: pre-treatment, metoclopramide (MCP) treatment (0.2 mg/kg orally three times daily), cabergoline (CAB) treatment (5 μg/kg orally once daily), post-treatment 1 and post-treatment 2. In the latter, only semen characteristics were evaluated. Semen parameters were analyzed once per week during the whole 15-week investigation time. At the end of each period, the effects of a single intravenous injection of thyrotropin-releasing hormone (TRH; 10 μg/kg) on the secretion of prolactin (PRL), LH, testosterone, thyroid-stimulating hormone and thyroxine (T4) were investigated. Pre-treatment serum PRL concentration increased under MCP (p < 0.05), followed by a decrease under CAB administration (p < 0.05). Luteinizing hormone and testosterone concentrations were not affected. Except for straight-line sperm velocity, semen quality did not differ between collection periods. A single iv TRH injection induced a significant PRL increase at 20 min in all experimental periods except during CAB treatment. Luteinizing hormone and testosterone did not show clear TRH-related changes. Basic T4 levels were significantly reduced after CAB treatment (p < 0.05). The results of the present study demonstrate that MCP-induced short-term hyperprolactinaemia in male beagles does not seriously affect the hypothalamo-pituitary axis and semen quality.     

Quantitative Evaluation of Equine Deep Digital Flexor Tendon Morphology using Magnetic Resonance Imaging

Injury of the distal aspect of the deep digital flexor tendon (DDFT) is a recognized cause of lameness, but diagnosis is difficult. This study aimed to improve understanding of DDFT morphology and pathology using retrospective evaluation of magnetic resonance (MR) images. We hypothesized that: (1) The distal aspect of the DDFT in normal horses would have a repeatable proximal/distal pattern and symmetry between limbs and between lobes; (2) DDFT dimensions would be related to bodyweight, navicular bone dimensions and hoof size; (3) this symmetry and pattern would be lost in DDFT injury; and (4) DDFT size would increase with injury. MR images of 64 live horse limbs, 26 with no identified DDFT lesion and 38 with identified DDFT abnormalities, and 19 normal cadaver limbs were analyzed. Using standardized transverse images, measurements of DDFT cross-sectional area, medial-lateral (ML) width and dorsal-palmar depth were obtained at six preselected sites. A uniform distal to proximal shape pattern was identified in all horses. The flattened crescent shape at the insertion changed to a deeper bilobed shape more proximally, with the mid-navicular area having the greatest cross-sectional area. Strong ML (P < 0.0006) and left/right symmetry (P < 0.02) were observed. In addition, there was a strong association between DDFT cross-sectional area and horse weight (P = 0.005) and between DDFT and navicular bone ML width (P = 0.004). Symmetry between sides or between lobes was lost at sites with a unilateral lesion and correlation between horse weight and DDFT cross-sectional area was lost in the presence of lesions. DDFTs with core lesions had a consistent increase in cross-sectional area overall, but other lesion types had no significant increase in size. The shape and symmetry seen in normal tendons could be related to the mechanical demands placed upon individual lobes. The limited increase in cross-sectional area with injury may be explained by the restrictive structures of the hoof, possibly explaining the ongoing pain seen in such lesions.     

Arthroscopic Removal of Palmar/Plantar Osteochondral Fragments from the Proximal Interphalangeal Joint in Four Horses

Objective— To describe anatomic considerations and arthroscopic technique in horses for arthroscopic removal of palmar/plantar osteochondral fragments from the proximal interphalangeal (PIP) joint. Study Design— Retrospective study. Animals— Adult horses (n=4) with osteochondral fragments of the palmar/plantar PIP joint. Methods— Arthroscopic removal of palmar/plantar osteochondral fragments within the PIP joint was performed with horses in dorsal recumbency under general anesthesia. Medical records of affected horses were reviewed to determine history; physical, lameness, and radiological findings; surgical technique; complications and outcome. Results— Two horses had lameness localized to the PIP joint. Two other horses had lameness suspected, but not confirmed to the pastern region. One of these horses had a history of intermittent lameness, but was not lame on admission. All horses had radiographic evidence of palmar/plantar osteochondral fragmentation within the PIP joint. Fragmentation was located abaxially in 2 horses in the hind limb and axially in 2 horses in the left forelimb. Osteochondral fragments were successfully removed via a palmar/plantar arthroscopic approach in all horses. Three horses returned to previous levels of athletic performance; 1 horse was used for trail riding instead of reining. Conclusions— Arthroscopy of the palmar/plantar pouch of the PIP joint allowed limited assessment of the joint and removal of osteochondral fragments. Clinical Relevance— Arthroscopy of the palmar/plantar PIP joint pouch for assessment and removal of osteochondral fragments is possible and should be considered when lameness is localized to this joint.