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To examine the effects of limited food intake on frequency and severity of osteoarthritis in coxofemoral joints of labrador Retrievers.Dogs were paired according to gender and body weight, within each litter at 8 weeks of age. One dog of each pair was fed ad libitum. The limit-fed pairmate was fed 75% of the amount eaten the previous day by the ad libitum-fed counterpart.48 Labrador Retrievers.All dogs received the same diet. Radiographic evaluation of coxofemoral joints for frequency and severity of osteoarthritis were made when dogs were 4 and 6 months and 1, 2, 3, and 5 years old.Radiographic evaluation for osteoarthritis indicated greater frequency and more severity of osteoarthritis in the ad libitum-fed group of dogs.Analysis of data suggested that limit feeding of dogs over a 5-year period minimizes development of osteoarthritis in the coxofemoral joints.

A 3-year prospective study of large-breed dogs (4 months to 3 years of age) was conducted to evaluate the influence of radiographic positioning and age on coxofemoral joint (hip) laxity, subjective hip score, and development of degenerative joint disease (DJD). The dogs (n = 142) were breeder- or client-owned and represented 14 breeds. With dogs under heavy sedation, hips were radiographed in the standard hip-extended position and in the new compression/distraction position at 4, 6, 12, 24, and 36 months of age. The standard hip-extended radiographic view was evaluated by 3 methods: subjective evaluation by a board-certified veterinary radiologist (WHR), according to the standard 7-point Orthopedic Foundation for Animals (OFA) scoring scheme (OFA/WHR); joint laxity quantitation, using the Norberg angle (NA) method; and subjective scoring by a veterinary orthopedic surgeon for radiographic evidence of DJD. The hips in the distraction radiographic view were evaluated for passive hip laxity, as measured by use of a unitless distraction index (DI). Results of the study indicated that at a specific age (4, 6, 12, 24, or 36 months), all methods of hip evaluation correlated with each other at a moderate level (P0.05). The strength of contemporaneous correlation tended to increase with age of evaluation. Longitudinally, the between-method correlations were usually significant (P0.05), but not at a sufficiently high level to permit reliable between-method prediction. Prospective intraclass (within-method) statistical analysis of the various hip-scoring methods indicated that DI was superior to NA and OFA/WHR in comparability of score over time. The intraclass correlation coefficient ranged from 0.55 to 0.91 for DI in contrast to 0.40 to 0.78 for NA, and 0.06 to 0.39 for OFA/WHR over the age intervals of the study. For reference, the highest Kappa of 0.39 for the subjective OFA/WHR scoring reflected a maximal level of agreement between time intervals, only slightly better than chance. The associated large error questions the predictive use of the 7-point, subjective hip-scoring scheme, particularly prior to the age of 2 years.

Forty-eight 8-week-old Labrador Retrievers were allotted to 2 groups of 24 dogs each; 1 group was fed ad libitum and the other group was given 25% less of the same feed until the dogs were 2 years old. Radiography of the hip joints was done when the dogs were 30, 42, 54, 78, and 104 weeks old. Subluxation was measured by the Norberg angle on radiographs made with the dog in the standard (extended limb) position. Independent of age at which the radiography was done, there was less subluxation of the femoral heads in the limit-fed dogs. Using the Swedish method of hip joint evaluation on the same radiographs, it was found that fewer dogs on limited food intake had signs of hip dysplasia. Radiographs done when dogs were 2 years old, for all the methods used (Norberg angle in standard and frog-limb position, the Orthopedic Foundation for Animals [OFA] score, and the Swedish score), revealed less hip dysplasia (less joint subluxation and less degenerative joint disease) in the limit-fed dogs. Using the OFA method, 7 of the 24 limit-fed dogs and 16 of the 24 ad libitum-fed dogs were diagnosed as having hip dysplasia. Similarly, using the Swedish method, 5 of the 24 limit-fed dogs and 18 of the 24 ad libitum-fed dogs were diagnosed as having hip dysplasia. The food-intake-related differences were significant both for the OFA score and for the Swedish score.(ABSTRACT TRUNCATED AT 250 WORDS)

From mechanical principles and postmortem observations of coxofemoral joints of dogs, a hydrostatic mechanism influencing hip joint stability was discovered. This discovery led to the development of a stress-radiographic positioning method to quantitate hip joint laxity in dogs. The method incorporated 2 views with the dog in supine position and hips at neutral flexion/extension angle: a compression view, with the femoral heads fully seated in the acetabula; and a distraction view, with the femoral heads at maximal lateral displacement. An index measurement method was formulated to quantitate the relative degree of joint laxity appearing in either the compression or distraction view. Clinical evaluation of 6 dogs was done to compare the compression/distraction method with the standard hip-extended radiographic method. Also, the stress-radiographic method was performed on 16-week-old Borzoi and German Shepherd Dogs to compare the characteristics of inherent hip joint laxity in these breeds. In all dogs tested, hip joint laxity was masked by the standard hip-extended view as indicated by a 2.5-fold improvement in sensitivity to hip joint laxity of the new method (P less than 0.00001). Moreover, the mean hip joint laxity of 16-week-old German Shepherd Dogs exceeded the mean hip joint laxity of Borzois by 79% (P less than 0.00001). Reports in the literature document the incontrovertible association of hip joint laxity to the development of hip dysplasia in dogs. We believe the ability to accurately quantitate hip joint laxity will provide key diagnostic and prognostic criteria for the selection of pet dogs, and more importantly, breeding stock.

The radiation response of acanthomatous epulis in 32 dogs was good, with an estimated median survival time of 21 months. Of the 32 patients, 14 have died. In 4 of those 14, malignant tumors developed at the site of the acanthomatous epulis. The tumors were of epithelial origin in 3 patients and of mesenchymal origin in 1 patient. Possibilities explaining the appearance of the malignancies included spontaneous malignant transformation, radiation induction of neoplasms, and radiation induction of malignant transformation. This uncommon complication was not considered contradictory to radiotherapy of acanthomatous epulides, because of their excellent response to irradiation and the long latent period between irradiation and appearance of the malignant tumor.

A 16-week-old male cat with urinary incontinence was initially diagnosed as having a right ectopic ureter. Other abnormalities of the urinary system included phimosis, hydronephrosis, and localized right megaloureter. Surgical removal of the right kidney and right ureter was partially successful in stopping the urinary incontinence. Further radiographic studies and retrospective examination of initial radiographs revealed that the left ureter was also ectopic.

Two of six cats receiving small-field, single-dose, brain irradiation of 35 Gy with 6 MeV photons developed brain abnormalities in the irradiated area on MR images at 6 and 8 months, respectively, after treatment. The lesions were of high intensity on T2-weighted images and did not enhance after IV administration of gadolinium-DTPA. An additional lesion in one of these cats displayed high signal on T2-weighted images and enhanced on T1-weighted images after IV gadolinium-DTPA. Pathologic correlation revealed that the nonenhancing T2-weighted lesions consisted of edema or demyelinated regions without inflammation while the gadolinium-enhanced lesion demonstrated necrosis with inflammatory infiltrate. Focal brain irradiation may produce noninflammatory demyelination and necrosis. These histologic entities may be potentially distinguished on MR with IV gadolinium-DTPA.

Seizures are possible complications of metrizamide myelography. The protective effect (as measured by reduction in seizure incidence) of dextrose in solution with metrizamide was studied by conducting a double-blind trail. Fourteen dogs each had two myelograms at five- to 16-day intervals in a crossover study, while ten additional dogs each had a single myelogram. Metrizamide alone and metrizamide in dextrose were used for the myelograms. No significant protective effect of dextrose was found.

Nine dogs with primary osteosarcoma also had concurrent bone infarctions. The median weight of the 9 dogs was less than 12 kg, and the median age was 10 years. Radiographically and histologically, bone infarctions were apparent in the limb bones and the cranium. Radiographically, there were multiple, irregular intramedullary densities, particularly in the limb bones. Histologically, there was widespread necrosis of the medullary soft tissue and bone, with proliferative new bone formation on medullary trabeculae. Collagen deposition throughout the vessel walls leading to occlusion was seen only in the intramedullary arteries.

Central diabetes insipidus was diagnosed in association with a dexamethasone-insuppressible adrenocorticotropin-secreting tumor in a dog. Over the 3 years before the dog's death, the combination of specific pituitary function tests, peptide hormone radioimmunoassays, and visualization of the tumor by use of x-ray computed tomography of the skull, allowed an etiologic diagnosis. Because initial signs of glucocorticoid excess were questionable and adrenolytic therapy was not allowed by the owners, treatment consisted only of administration of synthetic vasopressin, which was successful in the management of the diabetes insipidus.