Quantitative analysis of infiltrating immune cells and bovine papillomavirus type 1 E2-positive cells in equine sarcoids.

Sarcoids are the most frequently observed skin tumours in equids and consist of cutaneous accumulations of transformed fibroblasts. Their aetiopathogenesis is closely linked to a presumably abortive infection by bovine papillomavirus (BPV) types 1 and 2. In cattle, dermal fibropapillomas induced by BPV1/2 usually regress spontaneously due to a local, cell-mediated, immune response; however, equids appear to lack an effective immune response to BPV1/2 and mechanisms of immune evasion have been postulated. As a consequence, equine sarcoids tend to persist and are prone to recur. In this study, cryosections were analysed by immunofluorescent staining and a high content analysis system to determine the presence and distribution of CD4(+), CD8(+), FoxP3(+), RORγt(-), CD206(+) and CD14(+) cells, along with expression of the BPV1 early regulatory protein E2. A higher density of cells was positive for BPV1 E2(+) within the transformed tissue than in perilesional tissue or normal skin of horses with sarcoids and control horses. The proportion of CD8(+) cytotoxic T cells was significantly increased in perilesional and lesional tissues, whereas CD4(+) T helper cells were present in higher density only in lesional tissue compared to normal skin from horses with and without sarcoids. The proportion of pro-inflammatory CD4(+)FoxP3(+)RORγt(+) regulatory T cells was decreased in sarcoid tissue compared to perilesional, distant and control tissue. There were no significant differences in densities of CD4(+)FoxP3(+) RORγt(-) regulatory T cells between sarcoids and control tissues. Equine sarcoids are characterised by infiltrations of CD8(+) and CD4(+) T cells, with decreased representation by pro-inflammatory CD4(+)FoxP3(+)RORγt(+) regulatory T cells.

Thymoma-associated exfoliative dermatitis in cats.

Five cases of exfoliative dermatitis in cats were presented from 1996 to 2002 in which a feline thymoma was found by postmortem or postsurgical examination. Besides abundant exfoliation of keratin squames and layers, the histologic picture of the skin revealed a similar pattern of interface dermatitis with predominantly CD3+ lymphocytes and fewer mast cells and plasma cells. In the epidermal basal layer a hydropic degeneration of keratinocytes was present. In all cases an infundibular lymphocytic mural folliculitis and absence of or drastic decrease in the number of sebaceous glands occurred. In addition to the so far described cell-poor type, we also found examples of a cell-rich skin lesion. Together with the clinical observation of generalized exfoliative dermatitis, the histologic pattern of this dermatitis was suggestive of an underlying thymoma. The pathogenesis of this skin disease in association with thymic neoplasia remains obscure, and our results contradict the hypothesis of production of autoantibodies that cross-react with epithelial antigens. The morphology of the thymomas and CD3 expression of the thymocytes varied and did not seem to have an impact on the dermal lesions.

Feline relapsing polychondritis: two cases and a review of the literature.

Only 11 reports of cats with relapsing polychondritis (RPC) were found in the literature. We describe two additional cases and provide a review of the literature. Predominantly young to middle aged cats are affected (range 1.5 to 14.5 years, median 3 years). There is no sex predilection for feline RPC. In all cats with feline RPC, the ears were affected. The findings in one of our cases and one case in the literature raise the question if other organs such as the joints, the eyes or the heart may be involved in feline RPC. The histological lesions observed in biopsy samples of the ears were similar in all cats. Glucocorticoids were not effective in the treatment of RPC. Dapsone appeared to result in some clinical improvement but side effects were observed in one of four cats. Some cats improved without treatment.

Cultivation and characterisation of primary and subcultured equine keratinocytes.

We describe the establishment and characterisation of equine keratinocyte cultures with maintenance of a high proliferative capacity up to the second passage. Improved attachment and growth were obtained by seeding primary cells on equine feeder layers. Subcultured keratinocytes showed optimal growth when seeded on collagen type I. The proliferation rate of cells on this substrate exceeded that seen for cells seeded on equine feeder layers. By immunohistochemistry, epithelial origin and state of differentiation of the equine keratinocytes were determined. They expressed keratin and desmoplakin I/II, but lacked keratin 10. Electron microscopy revealed typical features of cultured keratinocytes. Purity of keratinocyte cultures was determined by vimentin staining. This is the first report on the establishment of equine keratinocytes derived from lip epithelium. It forms the basis to study equine keratinocyte biology and the pathogenesis of epidermal diseases. Since wound healing represents a severe problem in equine dermatology, our data may be essential for the establishment of new and improved therapy.

Immunoglobulin-E-bearing cells in skin biopsies of horses with insect bite hypersensitivity.

The aim of the present study was to investigate, with immunohistochemistry and in situ hybridisation, if immunoglobulin-E (IgE) and mast cells are involved in the pathogenesis of insect bite hypersensitivity (IBH), an allergic dermatitis of horses. In tissue sections fixed in paraformaldehyde (PFA) for <24 h, significantly more IgE protein-bearing cells were found in the dermis and epidermis of acute and chronic IBH lesions than in skin biopsies from healthy horses (medians = 466, 236 and 110 cells/mm2, respectively; P < or = 0.01). More IgE-mRNA positive (+) cells were observed in the dermis of acute IBH lesions than in the dermis of healthy skin (median = 2.8 vs. 0.0 cells/mm2; P < or = 0.01). Significantly, more mast cells were detected with metachromatic (median = 160 vs. 62 cells/mm2; P < or = 0.001) and tryptase-specific stainings (median = 120 vs. 69 cells/mm2; P < or = 0.001) in the dermis of acute IBH biopsies compared to healthy skin. No chymase+ mast cells were found in any skin biopsy. IBH lesions fixed in PFA for >24 h were compared to dermatomycosis (DM) lesions; IBH biopsies contained a similar number of IgE-protein+ cells to DM biopsies (median = 249 vs. 192 cells/mm2; P = 0.08) but had significantly more IgE-mRNA+, metachromatic and tryptase+ mast cells than DM biopsies. This study suggests an involvement of IgE-mediated immune reactions in the pathogenesis of IBH as well as, sometimes, in dermatomycosis. Using double labelling, cells which expressed IgE protein and contained mast cell enzymes were detected.

Mast cell density and subtypes in the skin of Shar Pei dogs with cutaneous mucinosis.

Skin biopsies from 13 Shar Peis showing signs of cutaneous mucinosis and 13 control dogs of different breeds with no clinical or histological evidence of skin disease were examined. One section of each tissue sample was stained with haematoxylin and eosin, and another with toluidine blue to demonstrate the sulphated acid glycosaminoglycans in mast cell (MC) granules. To investigate the MC subtypes involved, the tryptase and chymase content of mast cells was evaluated by a double enzyme-immunohistochemical staining technique. Regardless of the staining technique, a significantly lower mast cell density in the skin of Shar Peis was demonstrated. In the dermis of control dogs, we detected a median mast cell density of 31.2 MC/mm2 using the toluidine blue staining method and 27.5 MC/mm2 using the double labelling technique. In Shar Peis only 9.1 MC/mm2 were found by toluidine blue staining (P = 0.001) and 14.8 MC/mm2 by the double labelling method (P = 0.0387). The percentile distribution of mast cell subtypes was also significantly different in Shar Peis as compared to control dogs. Whereas in the dermis of control dogs the predominant mast cell subtype was the tryptase and chymase containing MC (TC-MC) (60.4%), in Shar Pei skin the only chymase containing MC (C-MC) predominated (62.2%) and the percentage of TC-MC was significantly lower (32.9%; P = 0.0016). The percentage of only tryptase containing MC (T-MC) (4.7%) was higher in Shar Peis compared to control dogs (1.9% P = 0.0178). The data obtained indicate a possible involvement of mast cell subtypes in the pathogenesis of cutaneous mucinosis. Further investigations on the pathophysiological role of mast cell subtypes may foster understanding of the pathogenesis of cutaneous mucinosis.

[Convulsions in relation to polycythemia: literature review and case description]. / Krampfanfälle im Zusammenhang mit Polyzythämie: Literaturübersicht und Fallbeschreibung.

Polycythemia--characterized by an excessive number of erythrocytes--is a rare disease in the dog with a chronic progressive course and unspecific symptoms. There are several forms: a primary, a secondary adequate or a secondary inadequate polycythemia. The clinical workup is done step by step and after stabilization of critical patients, the remaining therapy must address the primary cause. We report on a five year old male Leonberger dog suffering from secondary, inadequate polycythemia. He was presented with apathy, gait disturbances and disorientation. On the basis of the diagnostic workup a pathological process in the kidneys was postulated. Initially focal seizures became generalized later, most probably because of formation of a forebrain thrombus with secondary hypoxia. Even after emergency treatment the general state deteriorated. The course indicated possible sepsis. Because of the critical picture with secondary complications and the poor prognosis, the dog was euthanised. The histopathological results showed T-cell renal lymphoma and secondary injury to the forebrain.

DNA of bovine papillomavirus type 1 and 2 in equine sarcoids: PCR detection and direct sequencing.

Nucleotide sequences of bovine papillomavirus (BPV) DNA amplified by the polymerase chain reaction (PCR) from samples of equine sarcoid skin tumours were determined. All naturally occurring sarcoids (n = 58 tumours from 32 horses and 2 donkeys) contained BPV-DNA. All but 3 of the genome fragments belonged to the BPV type 1 strain (BPV-1); the remaining were BPV type 2. Similar results were obtained with cutaneous bovine papillomas used as controls (n = 20). One of the horses, carrying 2 sarcoids, was particularly interesting; one tumour contained BPV-1 DNA whilst the other sarcoid yielded BPV-2 DNA, suggesting that horses are not immune to super-infection. BPV-DNA was even amplified from the sarcoid samples which had yielded negative results in previous investigations when DNA isolated from the lesions was used in Southern blot hybridization with BPV probes. In addition, there was no detectable BPV-DNA in any equine or bovine tissue examined other than sarcoids or cutaneous bovine papillomas. Biopsies of normal skin surrounding lesions yielded exclusively negative results. The described nucleotide differences represent a natural genomic variation of this BPV type between geographically distant locations. The identical variations recovered from cattle and horses in Switzerland, a finding of great epidemiological interest, strongly suggest that a uniform variant of BPV-1 is one of the etiologic agents of equine sarcoid and bovine papilloma in a given region.

Classification of lung carcinomas in the dog and cat.

A total of 218 lung carcinomas from dogs and cats were examined histologically. The tumors were classified into adenocarcinoma, squamous-cell carcinoma, bronchial gland carcinoma, and alveolar-cell carcinoma. We believe that adenocarcinoma should be subdivided into differentiated and undifferentiated types because the two are distinct histologically and vary in frequency in the cat and dog. It is also important to recognize bronchial gland carcinoma, a distinct histological type, and to subdivide alveolar-cell carcinoma into three separate types: anaplastic small-cell and large-cell types, and adenomatosis type.

[Arterial repair after mechanical injury by migrating fourth-stage larvae of Strongylus vulgaris in the horse (a light and electron microscopic study) (author's transl)]. / Uber die Organisation von Thromben nach Arterienverletzungen durch wandernde 4. Larvenstadien von Strongylus vulgaris beim Pferd (licht und elektronenmikroskopishe Untersuchungen)

INTRODUCTION: Migrating fourth-stage larvae of Strongylus vulgaris, a parasite of equines, damage the intima of the anterior mesenteric artery and its larger branches and induce thrombus formation on the injured sites. As the time of larval passage through each of these branches has been exactly determined in earlier experiments, the aim of the present studies is to contribute to a more complete understanding of repair mechanisms in the process of time after thrombotic vascular injuries. MATERIAL AND METHODS: five foals were separated individually to specially cleaned stables and given anthelmintic treatment till the age of one year. One foal was infected per os with 350, the second with 500 and the remaining three with 1,000 third-stage larvae of Strongylus vulgaris...