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Biomedical subjects

R W Dunstan

Publications and source records attributed to R W Dunstan.

8 recordsLinked to original sources
PubMed1992

Aneurysmal bone cyst in a six-month-old dog.

A 6-month-old female Yorkshire Terrier was examined because of acute left forelimb lameness secondary to a Salter-Harris type IV fracture of the lateral condyle of the humerus. Radiography revealed an eccentric, osteolytic lesion in the distal humeral metaphysis associated with a pathologic fracture. The limb was amputated, and the dog recovered. Microscopic examination revealed an extensive zone of hemorrhage and dilated coalescent spaces, which were filled with blood. Hemosiderin-laden macrophages and multinucleated giant cells were observed throughout the stroma. On the basis of clinical, radiographic, and histologic examinations, a diagnosis of aneurysmal bone cyst was made. Aneurysmal bone cysts generally have been detected in 11- to 13-year-old, medium- to large-sized dogs. They can develop secondary to malignant processes.

Animals↗
PubMed1992

Dermal dendrocytes and T-cells in canine mycosis fungoides. Support for an animal model of human cutaneous T-cell lymphoma.

BACKGROUND: An extensive upper dermal network of human Thy-1+/Factor XIIa+ dermal dendrocytes (DD) exists in human mycosis fungoides (MF). METHODS: Immunophenotyping and morphologic studies on serial frozen and paraffin sections from 15 cases of canine MF were performed to see if a similar network exists in this disease, as has been proposed as an animal model of human MF. Primary antibodies were anti-human Factor XIIIa, Factor XIIIs, anti-canine Thy-1, CD4, CD8, CD18, CD45RA, Class II, MAC387, KP-1, EBM-11, and several other pan-T, pan-B, and pan monocyte markers. RESULTS: Thy-1+/Factor XIIIa+DD were seen in all cases and confirmed on identical cells by double immunofluorescence. These were seen throughout the upper dermis, similar to DD in human MF. Canine DD expressed the macrophage marker 2A2+, and were Class II+, CD4+, CD8-, CD18+, EBM11-, Factor XIII-, MAC387-, and KP-1. Epidermal and dermal lymphocytes in canine MF were Thy-1-, CD4+, CD8-, CD18+, CD45RA-, EBM11-, MAC387-, Factor XIIIa-, Factor XIIIs- in some cases, whereas others had a predominance of CD8+ lymphocytes. CONCLUSIONS: Thus, canine MF is immunophenotypically similar to human MF. Additional support for this disease as a model of human MF is demonstrated by the rich network of Thy-1+/Factor XIIIa+ DD in the upper dermis of canine MF similar to human MF.

Animals↗
PubMed1990

Congenital ichthyosis in a llama.

A 1-month-old male cria was examined because of diffuse hyperkeratosis and conjunctivitis that had existed since birth. The mucocutaneous junction of the nostrils as well as the neck, coronary bands, and axillary and inguinal regions were the most severely affected areas. Orthokeratosis involving the epidermis and follicular infundibula was observed on skin biopsy specimens. Electron microscopy revealed 4 to 6 granular layers and inter- and intracellular vacuolation in the stratum corneum; diagnosis of ichthyosis was established.

Animals↗
PubMed1990

A user's guide to veterinary surgical pathology laboratories. Or, why do I still get a diagnosis of chronic dermatitis even when I take a perfect biopsy?

During the past decade, clinicians have come to rely more heavily on veterinary surgical pathology services to provide assistance in the diagnosis of inflammatory and neoplastic skin disease. To obtain maximum results from each skin biopsy, it is important that clinicians have a good understanding of the factors that can affect histologic evaluation after the biopsy specimen has been removed from the patient. This article discusses the role proper tissue fixation, trimming, and grooming can play in obtaining an accurate histologic evaluation. The importance of understanding the limits of dermatopathology in establishing a definitive diagnosis of many inflammatory and neoplastic skin diseases is emphasized.

Animals↗
PubMed1989

Natural killer cell activity in untreated and treated dogs with lymphoma.

Natural killer (NK) cell activity and function were determined for 11 untreated and treated dogs with lymphoma. Concurrent chromium release and single cell binding assays, methods used to measure overall cytotoxic activity and that from individual cells, respectively, were performed at effector-to-target cell ratios of 50:1 and 100:1, with incubation periods of 12 and 16 hours. Significant reduction was achieved in overall activity for untreated dogs, using a 16-hour incubation period and an effector-to-target ratio of 100:1 (P less than 0.05). Decreased activity (P less than 0.025) was also achieved for those dogs that were administered combination chemotherapy, consisting of such drugs as cyclophosphamide, vincristine, prednisone, and doxorubicin. There was no significant difference in binding or cytotoxic activity by individual cells in the untreated or treated dogs, compared with the healthy controls. Short- or long-term treatment with glucocorticoids did not influence overall NK cll activity or individual cell cytotoxicity. The overall cytotoxic activity in untreated dogs was reduced, but these dogs had relatively normal numbers of NK cells compared with paracontrols. This suggests that a defect in recycling or the ability to kill targets repetitively, may be involved. A similar defect was found in NK cells of dogs treated aggressively with combination chemotherapy.

Animals↗
PubMedDate not supplied

Gastric conduit urinary diversion in normal dogs. Part I, Upper urinary tract structure, function, and sepsis.

The urinary bladder of 10 clinically normal dogs was excised and the ureters were implanted into an isolated, vagotomized gastric segment derived from the fundic region of the stomach. The gastric segment was closed to form a conduit. Continence was maintained with a modified Kock "nipple valve" created from an isolated segment of ileum. Four dogs were euthanatized by day 30 because of complications related to the early onset of renal failure and electrolyte alterations. Six dogs were euthanatized on day 150. Ureteral dilatation, hydronephrosis, and decreased endogenous creatinine clearance rates were measured in all dogs at the end of the survival period. Pyelonephritis was diagnosed histologically in seven dogs. Positive renal cultures were obtained from seven dogs at necropsy. It was concluded that gastric conduit urinary diversion is unsatisfactory for long-term or short-term clinical use in dogs.

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