Veterinary dermatohistopathology: what's new and exciting?
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Animals↗
Biomedical subjects
D W Scott
Publications and source records attributed to D W Scott.
Cutaneous hybrid cyst in four dogs.
Cutaneous hybrid cysts were recognized in 4 dogs. The lesions were solitary, asymptomatic, and occurred over the head, neck, proximal thigh, and lumbar region. These cysts were not accompanied by other disease processes, and did not recur following surgical excision. Histologically, the hybrid cyst is characterized by epidermal differentiation in its upper portion, and trichilemmal differentiation in its lower portion.
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Direct immunofluorescence testing of haired skin, nasal planum, and footpads of clinically normal woodchuck hepatitis virus-infected and non-infected woodchucks.
The purpose of this study was to determine the frequency of immunoreactant deposition in the skin, footpad, and nasal planum of 10 clinically normal, non WHV-infected woodchucks. The second part of the study investigated the frequency of immunoreactant deposition at the same sites in clinically normal, WHV-infected woodchucks, and compared these results with those reported in humans. Direct immunofluorescence testing of the haired skin, footpad, and nasal planum of all normal and 9 of the 10 WHV-infected woodchucks was negative. The footpad of 1 WHV-infected woodchuck revealed immunoreactant deposition in the walls of the superficial dermal blood vessels.
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Neoplasms of the apocrine sweat glands in 44 dogs and 10 cats.
Neoplasms of the apocrine sweat glands accounted for 2.0 per cent and 3.6 per cent, respectively, of all canine and feline skin neoplasms diagnosed during a period of three years. They occurred in dogs from six to 17 years of age of both sexes, and golden retrievers appeared to be predisposed; they occurred in cats from six to 17 years of age and there were no breed or sex predilections. In both species, the neoplasms were usually solitary and occurred anywhere on the body; they were nearly always carcinomas and histologically were usually of the solid type. There were no clinical measurements that made it possible to distinguish reliably between benign and malignant lesions. No distant metastases were recorded, even though 22.5 per cent of the canine carcinomas had invaded the lymphatic system.
Adenoma↗
Efficacy of chlorpheniramine maleate for management of pruritus in cats.
Chlorpheniramine maleate was administered orally (2 mg, q12 h) to 26 cats with pruritic skin disease. Pruritus was completely eliminated in 19 cats, and was reduced by 50% in 1 cat. Six cats had no response to treatment. Serious or long-lasting clinical side effects were not observed in any cat.
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Sterile nodular panniculitis in five horses.
Sterile nodular panniculitis was diagnosed in 5 horses. Physical abnormalities were predominantly limited to cutaneous changes, consisting of multiple subcutaneous nodules that had a tendency to wax and wane over time and were commonly distributed over the trunk, neck, and proximal portion of the limbs. In each horse, the diagnosis was confirmed by excisional biopsy of a nodule and by exclusion of infective causes of panniculitis on the basis of negative culture results and special stain application to skin specimens. Treatment with immunosuppressive doses of glucocorticoids was curative in 1 horse, was required on a daily or alternate-day schedule in 2 others to keep the skin clear, and had no effect on the disease in the remaining 2 horses.
Animals↗
Lymphoma models for B cell activation and tolerance. VIII. Cross-desensitization by sIgM and sIgD and its effects on growth regulation by anti-isotype antibodies.
ECH408-1 is a murine B cell lymphoma expressing idiotypically and allotypically distinguishable transfected and endogenous IgD. Previously, we demonstrated that this cell line was not growth inhibited by antibodies directed at membrane IgD, but could be inhibited by antibodies which crosslink membrane IgM. Herein, we demonstrate that both anti-mu and anti-delta will cause calcium mobilization in this transfected cell line; this is followed by a period during which antibodies against the alternative isotype are unable to induce significant increases in intracellular calcium concentrations. This phenomenon, called "desensitization," is short-lived, lasting 20 min. We further demonstrate that acute desensitization of these cells by anti-delta has no effect on immediate growth inhibition which is elicited by anti-mu. These data confirm our earlier proposal that the rapid, initial calcium response seen in these lymphomas is not required for the negative signal for growth. Moreover, we also demonstrate that pretreatment of these lymphoma cells with phorbol myristate acetate (PMA) also renders these lymphoma cells temporarily incapable of manifesting a significant calcium signal. Nonetheless, PMA-pretreated B lymphoma cells are not altered in their subsequent sensitivity to anti-mu growth inhibition, nor are they affected in their resistance to inhibition by anti-delta. Our data confirm the proposal that neither the calcium signal nor protein kinase-C activation is involved in the modulation of B lymphoma growth.
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Subcorneal pustular dermatosis in dogs and in human beings: comparative aspects.
Subcorneal pustular dermatosis is a rare disorder in dogs and in human beings. A retrospective study of 13 cases of canine subcorneal pustular dermatosis indicates that many of the clinicopathologic features of this disease are similar in both species. In both the condition is characterized by a variably pruritic, sterile, pustular eruption that is resistant to antibiotics and glucocorticoids. The therapeutic response to dapsone is not uniformly successful in either species, and the disorder tends to be chronic and recurrent.
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Two rare cutaneous neoplasms in horses: apocrine gland adenocarcinoma and carcinosarcoma.
Two rare equine cutaneous neoplasms, an apocrine gland adenocarcinoma and a carcinosarcoma were diagnosed in a 17-year-old pony and a 14-year-old mare, respectively. The apocrine gland adenocarcinoma was present on the prepuce. Histologically, papillary projections of low cuboidal to columnar epithelial cells were generally well differentiated, and surrounded dilated acini. Stromal invasion was present, but vascular and lymphatic invasion was not seen. The carcinosarcoma was present in the right flank of the mare. Two discrete cell populations were characterized histologically. One portion of the mass was composed of elongated, loosely arranged mesenchymatous cells; the second population consisted of dense sheets of pleomorphic, basophilic cells forming irregular acini.
Adenocarcinoma↗
Nonsteroidal management of canine pruritus: chlorpheniramine and a fatty acid supplement (DVM Derm Caps) in combination, and the fatty acid supplement at twice the manufacturer's recommended dosage.
Forty-three dogs having pruritus associated with atopy, flea bite hypersensitivity, and idiopathy were randomly assigned to 1 of 2 treatment protocols. Twenty-three dogs received chlorpheniramine in combination with a fatty acid supplement (DVM Derm Caps). Twenty dogs received the fatty acid supplement at twice the manufacturer's recommended dosage. All 43 dogs were known to be unresponsive to chlorpheniramine and the manufacturer's recommended dosage of the fatty acid supplement when either drug was used alone. Pruritus was satisfactorily controlled in 34.8% of the dogs in the chlorpheniramine--DVM Derm Caps protocol. No dog in the double DVM Derm Caps protocol showed a beneficial response. Side effects were uncommon and mild with either protocol.
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Seasonal flank alopecia in ovariohysterectomized dogs.
Recurrent seasonal flank alopecia was recognized in 5 ovariohysterectomized female dogs. The dogs first developed hair loss between 1 1/2 and 4 1/2 years of age. The hair loss began in March or April (spring) and spontaneously resolved in July or August. The dogs were otherwise healthy, and no cause for the condition could be determined.
Alopecia↗
Black-hair follicular dysplasia in a Holstein cow.
A color-linked hypotrichosis was documented in an adult, black-and-white, Holstein cow. Skin biopsies from black-haired areas showed varying degrees of follicular dysplasia, while the white-haired areas were normal.
Alopecia↗
Direct immunofluorescence testing of normal feline nasal planum and footpad.
Direct immunofluorescence testing for IgG, IgM, and C3 was performed on nasal planum and footpad tissue from 28 normal cats. Granular deposition of IgM at the basement membrane zone of the nasal planum was demonstrated in 3 of 28 cats. Direct immunofluorescence testing of the footpad was negative in all cats. It was concluded that positive direct immunofluorescence testing of the feline nasal planum using antifeline IgM needs to be cautiously interpreted, as 11% of normal cats may be positive.
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Suppression of antibody synthesis by CD4+ T cell clones and normal T cells stimulated with monoclonal anti-CD3 antibody.
CD4+ve Th1 clones, as well as normal splenic T cells, were found to suppress LPS-driven antibody secretion in a non-Ag-specific and non-MHC-restricted manner when the T cells were activated with the anti-CD3 mAb, 145-2C11. Suppression was observed with both primed and naive B cells, as well as with purified hapten-specific B cells, a result that suggests a direct effect of anti-CD3-activated T cells on B cell differentiation. Th1 clones activated by cognate Ag also suppressed LPS-driven antibody secretion. Furthermore, suppression of LPS-driven antibody secretion could be achieved across a cell-impermeable porous membrane when T cells were activated with anti-CD3. Suppression by Th1 clones and by normal T cells could not be attributed to a concomitant decrease in B cell proliferation or to a shift in the kinetics or isotype of the antibody response. These data demonstrate that CD4+ve Th1 clones, as well as normal T cells, can effect suppression of polyclonal antibody formation.
Adjuvants, Immunologic↗
Squamous cell carcinoma of the nail bed in three related giant schnauzers.
Three black giant schnauzers, mother, daughter and son, developed single or multiple primary squamous cell carcinomas of the nail bed between the ages of nine and 12 years. The clinicopathological findings are described. Radiographic evidence of osteolysis of the third phalanx, especially in a middle-aged to older large-breed, black dog would warrant the amputation and histopathological examination of the digit because of the likelihood of squamous cell carcinomas.
Animals↗
Cholera toxin-sensitive and insensitive signaling via surface Ig.
We have observed that a 2-h pretreatment of murine B cells with cholera toxin (CT) renders the B cell incapable of receiving an activation signal via surface Ig as measured by cell volume increase and entry into the S phase of the cell cycle. In contrast, CT pretreatment does not inhibit the delivery of a signal by IL-4, as measured by increase in cell volume. In fact, CT pretreated B cells are able to respond to anti-Ig in the presence of IL-4, as measured by both an increase in cell size and entry into S suggesting that IL-4 overcomes the effects of CT on normal B cell activation. Despite blocking the anti-Ig-mediated entry into the cell cycle, CT was not able to interfere with the induction of nonresponsiveness by anti-Ig in normal B cells or with the delivery of growth-inhibitory signal to the B cell lymphoma WEHI-231. These results suggest that there are two signaling pathways mediated by cross-linking of surface Ig: one pathway sensitive and the other insensitive to modulation by CT.
Animals↗
The dilated pore of Winer--an overlooked cutaneous lesion of cats.
A retrospective study of 125 cutaneous cystic lesions in cats from 1978 to 1987 Revealed 14 examples of the dilated pore of Winer, a lesion previously described in man and in one cat. Histologically, this lesion appears as a flasklike cystic structure with a wide external opening and laminated keratinaceous content. The cyst is characterized by a thickened wall with numerous, closely apposed rete ridges, either at its base or throughout most of the circumference, with a thinner atrophic wall approaching the os. Clinically, the lesion is a hairless nodule or visible cutaneous defect containing either soft keratinaceous material or, more commonly, projections of horn-like material. In man, the lesion is believed to be either a hamartoma or a benign neoplastic process. Surgical excision is curative.
Animals↗
Cartilaginous metaplasia associated with a basal cell tumour in a dog.
Locally extensive dermal cartilaginous metaplasia was seen in association with a pigmented basal cell tumour in an aged, spayed Basenji dog. Six months after surgical excision, the animal remains healthy with no recurrence of the neoplasm.
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