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Biomedical subjects

R W Dunstan

Publications and source records attributed to R W Dunstan.

At least 37 records · Page 2Linked 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↗
PubMed1990

Inherited mouse mutations as models of human adnexal, cornification, and papulosquamous dermatoses.

Nearly 100 mouse mutations have been described as causing some type of abnormality of the skin or hair. As only a few of these mutations have been studied in detail, they remain an untapped resource for furthering knowledge of basic cutaneous physiology and understanding the pathophysiology of analogous diseases in humans. Several diverse murine mutations are discussed. These include "asebia," a mildly hyperkeratotic disorder with sebaceous gland hypoplasia; "ichthyosis," an example of abnormal hair growth associated with hyperkeratosis; "rhino" and "hairless," two related examples of congenital follicular malformations; and "flaky skin", a potential animal model of eruptive psoriasis.

Animals↗
PubMed1989

Extraskeletal osteosarcoma in two dogs.

Extraskeletal osteosarcoma (ESOS) of the spleen and jejunum was diagnosed in 2 dogs. As an extremely uncommon type of tumor that has proven difficult to treat, ESOS is associated with high rate of local recurrence and metastatic disease. Extraskeletal osteosarcoma principally affects older dogs, has no apparent breed predilection, and may develop more frequently in males. The cause of ESOS is unknown, but may involve malignant metaplasia of pluripotential mesenchymal cells into osteoblasts. Macroscopically, ESOS usually is observed as a hard mass and may appear similar to calcified hematoma or myositis ossificans. The classic radiographic appearance of ESOS is a soft tissue mass with focal mineralization and without adjacent bone involvement.

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↗
PubMed1988

Neuroendocrine carcinoma of the gallbladder in a dog.

A 9-year-old Bullmastiff with hematemesis was determined to have primary neuroendocrine carcinoma of the gallbladder. Despite the dismal prognosis when these unusual tumors are located in the liver, the hematemesis resolved, and there was no obvious tumor regrowth in this dog 10 months after cholecystectomy.

Animals↗
PubMed1988

Bacterial population and histologic changes in dogs with perianal fistula.

Ages of 44 dogs with perianal fistula, ranged from 6 months to 13 years (mean, 5.2 years). German Shepherd Dogs and Irish Setters were statistically (P less than 0.01) over-represented compared with those breeds in a canine hospital population (n = 22,047) for the same period. There was a 2:1 male-to-female ratio, with 38 (86.4%) of dogs sexually intact and 6 (13.6%) of dogs neutered. Eleven types of bacterial organisms were recovered from deep perianal tissues of which Escherichia coli, Staphylococcus aureus, beta-hemolytic streptococci, and Proteus mirabilus were most common. Organisms were not recovered from 7 dogs. Of 93 isolates, 88.3% were susceptible to gentamicin, 80.5% to cephalothin, 79.2% to chloramphenicol, and 74% to trimethoprim-sulfamethoxazole. Fifty-one biopsy specimens from 44 dogs were classified as having early, intermediate-, and late-stage lesions based on the amount of fibrosis, severity of the inflammatory response, and, if present, depth of sinus tracts. In most biopsy specimens, all 3 stages were represented in the same histologic section. In 45 specimens, most inflamed lesions were in the dermis of the zona cutanea. Hidradenitis was present in 22 biopsy specimens and was associated with the formation of epithelial-lined sinus tracts.

Anal Canal↗
PubMed1988

A disease resembling junctional epidermolysis bullosa in a toy poodle.

A disease resembling junctional epidermolysis bullosa in humans is described in a toy poodle. Shortly after birth, the affected animal developed vesicles and bullae on the pads of the feet and the mucous membranes of the oral cavity. The lesions rapidly increased in number and severity, eventually involving the glabrous skin of the ventral abdomen. Due to the severity of the lesions, the animal was euthanized when it was 48 h old. Histopathologic, ultrastructural and immunohistochemical evaluation defined a minimally inflamed subepidermal vesicular disease with separation occurring at the zona lucida of the basement membrane zone. Laminin and type IV collagen were present at the base of the vesicle.

Animals↗
PubMed1987

Synovial chondrometaplasia in five dogs.

Synovial chondrometaplasia was diagnosed in 5 dogs. Four dogs improved dramatically after surgical removal of subsynovial nodules, but the fifth improved only slightly. This potentially treatable condition is recognized in human beings, and has been described in dogs in the German scientific literature. Synovial chondrometaplasia should be suspected if numerous joint mice are visualized radiographically, without an obvious inciting cause. It also should be suspected when periarticular osteophytes are found radiographically in unusual locations.

Animals↗
PubMed1987

Hyperadrenocorticism in a cat.

A diabetic cat with hyperadrenocorticism had polydipsia, polyuria, ventral abdominal alopecia, thin dry skin, and a pendulous abdomen. Results of laboratory testing indicated persistent resting hypercortisolemia, hyperresponsiveness of the adrenal glands (increased cortisol concentration) to ACTH gel, and no suppression of cortisol concentrations after administration of dexamethasone at 0.01 or 1.0 mg/kg of body weight. Necropsy revealed a pituitary gland tumor, bilateral adrenal hyperplasia, hepatic neoplasia, and demodicosis. Adrenal gland function was concurrently assessed in 2 cats with diabetes mellitus. One cat had resting hypercortisolemia, and both had hyperresponsiveness to ACTH gel (increased cortisol concentration) at one hour. After administration of dexamethasone (0.01 and 1.0 mg/kg), the diabetic cats appeared to have normal suppression of cortisol concentrations. The effects of mitotane were investigated in 4 clinically normal cats. Adrenocortical suppression of cortisol production occurred in 2 of 4 cats after dosages of 25, 37, and 50 mg/kg. Three cats remained clinically normal throughout the study. One cat experienced vomiting, diarrhea, and anorexia.

Adrenal Cortex↗
PubMed1986

Feline sporotrichosis: a report of five cases with transmission to humans.

Sporotrichosis was diagnosed in five cats. Seven humans exposed to these cats subsequently developed the disease. All feline cases developed draining ulcers, and in four of five cases there was disseminated cutaneous involvement. Histologically, numerous Sporothrix organisms were noted in cutaneous lesions and overlying exudate. The seven humans who became infected were involved in cleaning and medicating cats with the disease; all human patients developed a localized lymphocutaneous form of sporotrichosis. In four of the human cases there was no history of an associated penetrating wound. The large number of Sporothrix organisms is a distinct feature of feline sporotrichosis and indicates that the cat may be the only domestic animal species that can readily transmit this disease to humans. In addition, any contact with the draining lesions of affected cats offers the potential for human infection.

Adult↗