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Ocular-chondrodysplasia in Labrador Retriever dogs is characterized by short-limbed dwarfism and ocular abnormalities. The purposes of the present study were to develop morphological criteria to define the matrix and/or chondrocytic abnormalities associated with this chondrodysplasia, and to test the hypothesis that ineffective matrix-directed cellular swelling was associated with the decreased longitudinal bone growth in these animals. The proximal and distal radial growth plates were collected from four affected animals of the same litter. Stereological techniques were used to analyze both cellular shapes and cellular volume changes in the hypertrophic zone. The pathological changes seen in these growth plates varied between animals and included disorganization of cellular columns with abnormal extent of calcification. Chondrocytes of all zones contained two types of abnormal cellular inclusions classified as light and dark, based on the intensity of eosinophilic staining. Both types of inclusions contained material that resembled the surrounding extracellular matrix, varying only in the apparent hydration of the contents. It could be demonstrated that light inclusions were located in the peripheral cytoplasm and connected to the extracellular matrix through narrow channels. By contrast, dark inclusions were membrane bound and perinuclear. Chondrocytes with multiple, large inclusions appeared to be undergoing degenerative changes. Although the final volume achieved by hypertrophic chondrocytes was consistent with that of normal growth plates, there was a high level of variability of chondrocytic shape and evidence of premature cellular condensation in the maturation zone. The severity of the dwarfism correlated both with the extent of chondrocytic changes and the severity of the ocular lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Electron microscopy was used to diagnose primary ciliary dyskinesia in a litter of English pointer dogs and in a golden retriever dog. A technique of membrane solubilization, fixation, and negative staining with glutaraldehyde tannic acid identified abnormally constructed central and B microtubules in respiratory cilia from dogs with primary ciliary dyskinesia. Shortened outer dynein arms commonly associated with primary ciliary dyskinesia actually represents the absence of a specific subset of the three most peripheral components of the whole outer dynein arm structure.

An 11-year-old Dalmatian was examined and treated for bilateral nasal discharge and cough of 6 months' duration. Response to medical treatment and surgical intervention was unsatisfactory. Histologic examination of lung tissue revealed chronic severe catarrhal bronchitis and bronchiolitis with bronchiectasis. Histologic findings and barium sulfate bronchography indicated abnormal mucociliary clearance in the respiratory tract. Electron microscopy revealed abnormalities or deletions of outer and/or inner dynein arms in 26% of the ciliary profiles from the affected dog. Similar abnormalities were not found in 500 ciliary profiles from age- and gender-matched control dogs.

Compared with neutrophils from healthy dogs, neutrophils from 2 dogs with primary ciliary dyskinesia had increased distance of random migration, but fewer of the neutrophils migrated. The affected dogs had an increase in the numbers of Staphylococcus aureus phagocytized. Lymphocyte blastogenesis in the affected dogs in response to standard mitogens was considered to be normal.