Fascin‐1 expression in canine cutaneous and oral melanocytic tumours

Fascin‐1 expression was examined in 9 cutaneous melanocytomas and 47 oral melanomas. The cases were scored on the basis of extent and intensity of staining, and combined scores were calculated. Fascin‐1 expression was observed in 5/9 (56%) melanocytomas and 46/47 (98%) melanomas. The combined score for fascin‐1 was significantly greater in stage III/IV melanomas than in stage I/II melanomas (P < 0.05). In addition, strong fascin‐1 staining was associated with a significantly shortened survival time (P < 0.05). The results of this study suggest that fascin‐1 overexpression correlates with the malignancy of canine melanoma and has the potential to be a new immunohistochemical marker to predict the clinical course of canine melanoma. In addition, targeted therapy for fascin‐1 may represent a new strategy for the treatment of canine melanoma.     

Resolution of persistent oral papillomatosis in a dog after treatment with a recombinant canine oral papillomavirus vaccine

This report describes a 16‐month‐old female, otherwise seemingly healthy, Siberian husky dog with severe oral papillomatosis that did not regress spontaneously and was refractory to surgical treatment over a 6‐month period. Regression of the papillomas was achieved by administering a series of experimental vaccinations starting at the time of the last surgery. The vaccine consisted of systemically administered canine oral papillomavirus major coat protein L1 that has been shown to self‐assemble into virus‐like particles. They cause a humoral response that has been shown to prevent the onset and development of papillomas. In this case, however, following unsuccessful surgical treatment, the vaccine acted therapeutically, causing the papillomas that had regrown to shrink. No side‐effects were noted.     

Immunohistochemical investigation of canine episcleritis

OBJECTIVES: To identify macrophages, B cells and T cells in archived canine episcleral biopsies and to correlate these findings with the clinical presentation and therapeutic outcome. PROCEDURES: Archived formalin-fixed biopsies were immunohistochemically labeled for CD18, CD79a, and CD3 to identify macrophages, B cells and T cells, respectively. Slides were digitally photographed and positive cells were manually counted. Signalment, duration of illness, affected eye(s), treatment, and therapeutic outcome were reviewed for each dog. Dogs were divided into groups based on clinical presentation (unilateral episcleritis, bilateral episcleritis or nodular granulomatous episclerokeratitis (NGE). RESULTS: Twenty-four cases were evaluated. There were 19 episcleritis (13 unilateral, six bilateral) and five NGE cases. The mean age for clinical manifestations of unilateral episcleritis was 6.8 years, bilateral episcleritis was 8.7 years, and NGE was 3.8 years. The Cocker Spaniel was over-represented in the episcleritis groups. All NGE cases were Collies. Approximately 50% of the unilateral episcleritis cases resolved and did not require long-term therapy. Almost all cases of bilateral episcleritis and NGE required continuous medical therapy to maintain remission. There was a significantly higher percentage of B lymphocytes in biopsies from lesions that required ongoing medical therapy to maintain lesion remission than in the lesions that resolved, and for which medications were discontinued (P = 0.0471). CONCLUSIONS: The prognosis for resolution of NGE and bilateral episcleritis without long-term medical therapy is poor. There is a significant difference in the inflammatory cell population in episcleritis that resolved with medical therapy vs. episcleritis that required ongoing medical therapy.     

MIB‐1 immunoreactivity correlates with biologic behaviour in canine cutaneous melanoma

The growth fraction of 68 canine cutaneous melanomas was determined by immunostaining with MIB‐1, a monoclonal antibody to a Ki‐67 epitope that recognizes all proliferating cells. Fifty tumours were classified histologically as benign and 18 as malignant. The Ki‐67 proliferative index (percentage of positive cells over 500 neoplastic cells) was low (< 15%) in 55 cases and high ( 15%) in 13 cases. High Ki‐67 proliferative index and histological malignancy were both associated with significantly poorer 2‐year survival (P < 0.0001). However, the predictive value of the Ki‐67 proliferative index (97%) was higher than the predictive value of classical histology (91%). The evaluation of the growth fraction by the Ki‐67 proliferative index is highly predictive of the biological behaviour of canine cutaneous melanoma.     

Immunohistochemical localization of androgen and oestrogen receptors in canine hair follicles

Skin biopsies from seven different body sites were obtained from 21 dogs of different breeds (short, normal, long hair), which were presented for euthanasia. Commercially available polyclonal antibodies were used for the immunohistochemical detection of androgen and oestrogen receptors. Both receptors showed a similar distribution in canine skin, with specific intranuclear staining. In the epidermis, the percentage of androgen receptor (AR)-positive cells, but not that of oestrogen receptor (ER)-positive cells, was significantly higher in samples from the thorax and the flank. In the dermal papilla, the percentage of ER-positive (but not AR-positive) cells was significantly lower in biopsies from the flank. No significant difference was found for both receptors between the locations in the outer root sheath, among the three different hair types, between sex and between intact and castrated dogs.     

Up-regulation of cytokeratin expression in canine distemper virus-infected canine footpad epidermis

Cytokeratin expression was assessed in footpad epidermis from dogs using immunohistochemistry. Four groups of dogs were studied: dogs with experimentally induced distemper and with canine distemper virus (CDV) in footpad epidermis (group 1, n = 7); dogs with experimentally induced distemper and without CDV in footpad epidermis (group 2, n = 4); inoculated dogs without distemper and without CDV in the footpad epidermis (group 3, n = 8), and noninoculated dogs without distemper (group 4, n = 2). No increase in thickness of the footpad epidermis was present in any of these groups. Sections of metacarpal or metatarsal pads were stained for cytokeratin (CK)14 (proliferation-associated), CK10 (correlated with early differentiation), and for involucrin (associated with terminal differentiation). CK14 was present in basal keratinocytes of all groups, but staining intensity decreased towards the corneal layer in groups 2-4, but not in group 1. CK10 was present in the spinous and granular layer of all groups, but staining of the granular layer was much stronger in group 1. Involucrin was present in the granular layer of footpads of group 1 and only in the upper part of this layer in groups 2-4. The results demonstrate increased staining intensity and/or wider distribution within the footpad epidermis in group 1 dogs when compared to the other groups. This was interpreted as up-regulation in expression of these proteins. These findings suggest that presence of CDV antigen and mRNA in footpad epidermis was associated with an increase in expression of CK14, CK10 and involucrin. The potential role of this up-regulation in cytokeratin expression in the development of CDV-induced digital hyperkeratosis remains speculative at the moment and requires further studies.     

Atypical necrotizing encephalitis associated with systemic canine distemper virus infection in pups

This report describes the naturally occurring atypical neuropathological manifestation of systemic canine distemper virus (CDV) infection in two 16-day-old Pit Bull pups. CDV-induced changes affected the gray and white matter of the forebrain while sparing the hindbrain. Histologically, there was necrosis with destruction of the nervous parenchyma due to an influx of inflammatory and reactive cells associated with eosinophilic intranuclear inclusion bodies within glial cells. Positive immunoreactivity against CDV antigens was predominantly observed within astrocytes and neurons. RT-PCR was used to amplify CDV-specific amplicons from brain fragments. These findings suggest the participation of CDV in the etiopathogenesis of these lesions.     

Comparative immunohistochemical characterization of canine seminomas and Sertoli cell tumors

Primary testicular tumors are the most common causes of cancer in male dogs. Overall, the majority of canine patients should be cured by testicular surgery. However, tumor markers are not well-known in veterinary medicine. We sought to determine using immunohistochemistry whether the combined human testicular tumor markers (placental alkaline phosphatase, OCT3/4, CD30, alpha-fetoprotein, inhibin-alpha, vimentin, c-KIT, and desmin) are expressed in canine seminomas and Sertoli cell tumors (SCTs). We examined 35 canine testicular tumors, 20 seminomas and 15 SCTs. c-KIT was expressed markedly in canine seminomas. Both inhibin-alpha and vimentin were expressed significantly in canine SCTs. The results of this study demonstrate differences and similarities between tumor marker expression of testicular tumors in dogs and humans. All the main markers in current routine use are discussed as well as potential useful markers for benign and malignant tumors, and tumor progression.     

Analysis of genomic mutation and immunohistochemistry of platelet‐derived growth factor receptors in canine vascular tumours

We examined whether mutation of the platelet‐derived growth factor receptor protein tyrosine kinase (PDGFR)‐α and PDGFR‐β genes contributes to their overexpression in canine vascular tumours. Genomic sequences of trans‐ or juxtamembrane regions of PDGFR‐α and PDGFR‐β were analysed with immunohistochemical staining and polymerase chain reaction‐direct sequencing using DNA from paraffin‐embedded neoplastic tissues of 27 hemangiosarcomas (HSAs) and 20 hemangiomas (HAs). Immunohistochemically, 75% of the HA cases were positive for PDGFR‐α and almost most of the HA cases were negative for PDGFR‐β. Of the HSA cases, 55.6% were negative for PDGFR‐α and 63% were strongly positive for PDGFR‐β. Among the HA cases, 1 missense mutation was detected in PDGFR‐α exon 18 and 1 in PDGFR‐β exon 17. Two HSA cases had missense mutations in exon 14 and 1 in exon 17 of PDGFR‐β. Thus, genomic mutation of trans‐ or juxtamembrane regions of PDGFRs was not the main mechanism driving the activation of receptors in HSA and HA.     

犬瘟热病毒野毒株与疫苗株鉴别检测RT-LAMP方法的建立

为建立一种鉴别犬瘟热病毒(CDV)野毒株与疫苗株的反转录-环介导等温扩增方法(RT-LAMP),本研究通过比对野毒株与疫苗株H基因设计特异性引物,对反应体系中的Mg2+、Betaine、Bst DNA Polymerase、dNTP和反应温度等条件分别进行优化,建立用于鉴别检测CDV野毒株与疫苗株的RT-LAMP。建立的RT-LAMP方法检测CDV野毒株时,在65℃水浴锅中反应40 min即可完成。该方法具有高度特异性,对犬细小病毒、犬腺病毒、狂犬病毒、犬冠状病毒无交叉反应,敏感度可达40 copies/μL,是常规RT-PCR方法的100倍。     

Expression of cell adhesion molecules in canine choroid plexus tumors

Choroid plexus tumor (CPT) is a primary intracranial neoplasm of the choroid plexus epithelium in the central nervous system. In the current World Health Organization classification, CPT is classified into two categories; choroid plexus papilloma (CPP) and carcinoma (CPC). In the present study, we investigated immunohistochemical expressions of N-cadherin, E-cadherin and β-catenin in 5 canine CPT cases (1 disseminated CPC, 2 CPCs and 2 CPPs). One CPP case was positive for N-cadherin and β-catenin, but negative for E-cadherin. The disseminated CPC case was positive for E-cadherin and β-catenin, but negative for N-cadherin. The other cases were positive for the three molecules examined. These results suggest that loss of the N-cadherin expression might associate with the spreading of CPC cells.     

Concurrent Cryptosporidium and parvovirus infections in a puppy

Cryptosporidium parvum, an intestinal coccidian parasite, was isolated from faeces and intestinal biopsies of a 9-week-old puppy with acute parvoviral gastroenteritis. Gene sequence analysis identified a Cryptosporidium genotype not previously recorded in Australia. The puppy recovered after treatment with crystalloid fluids, synthetic and natural colloids and jejunostomy tube feeding.     

Sensitivity to antibiotics amongst cutaneous and mucosal isolates of canine pathogenic staphylococci in the UK, 1980–96

Abstract Disc sensitivity tests were carried out on 2296 isolates of non-pigmented, coagulase-positive staphylococcal isolates from dogs in referral practice over the period 1980–96. Ninety-eight isolates were from the ears, 1089 from other skin regions and 37 from mucosae. Resistance to penicillin increased from 69.0 to 89.3%. Oxytetracycline resistance remained at about 40%; resistance to erythromycin and lincomycin, and to co-trimoxazole peaked at about 20 and 15%, respectively, in 1987–89 but has since fallen. Only a single isolate resistant to cephalexin was found between 1986 and 1996. No resistance to co-amoxyclav, oxacillin, methicillin and enrofloxacin was demonstrated. Resistance of mucosal isolates was higher than those from skin. Multiple isolates from 90 dogs showed different resistance spectra in 56% of cases indicating that single swab samples are of limited value in determining optimal therapeutic antibiotics. Resumé 2296 souches de staphylocoques coagulase positifs, isolées á partir de chiens présentés en consultation référée entre 1980 et 1996, subirent des tests de sensibilité sur disques. 98 souches étaient d'origine auriculaire, 1098 d'autres origines cutanées, et 37 d'origine muqueuse. La résistance á la pénicilline augmenta de 69, 0 á 89, 3 pour cent. La résistance a l'oxytetracyline resta stable á environ 40 pour cent; les résistances á l'erythromycine et á la lincomycine, et au co-trimoxazole atteignirent 20 pour cent et 15 pour cent respectivement de 1987 á 1989 mais baissèrent ensuite. Une seule souche resistante á la cephalexine fut isolée entre 1986 et 1996. Aucune résistance á l'amoxycilline-acide clavulanique, Foxacilline, la methicilline, et l'enrofloxacine se fürent découvertes. Les résistances des souches d'origine muqueuse étaient plus nombreuses que celles des souches d'origine cutaneé. Des souches isolées par prelevement multiples chez 90 chiens montraient des spectres de résistance différents dans 56 pour cent des cas ce qui montre que des écouvillonages uniques ont un interèt limité pour le choix de la meilleure antibiotherapie. [Lloyd, D.H., Lamport, A.I., Feeney, C. Sensitivity to antibiotics amongst cutaneous and mucosal isolates of canine pathogenic staphyloccoci in the United Kingdom, 1980–96 (Antibiosensibilité de souches de staphylocoques pathogènes canins d'origines cutanee et muqueuse au Royaume Uni de 1980 a 1996). Veterinary Dermatology 1996; 7 : 171–175.] Resumen A continuación el autor describe como discos de antibiograma fueron utilizados en 2.296 aislamientos caninos de no pigmentados estafilococos coagulasa positiva durante el periodo de 1980 a 1996; 98 aislamientos a partir del oido, 1098 de otras partes de la piel y 37 de mucosas. Se observó que las resistencias a la penicilina aumentaron de 69, 0 a 89,3 por ciento; a la oxitetraciclina permanecieron constantes, alrededor del 40 por ciento. Con respecto a la eritromicina y lincomicina asi como al cotrimoxazol, el nivel de resistencias alcanzó un pico máximo de alrededor 20 y 15 por ciento respectivamente en 1987–1989 para disminuir desde entonces. Solo un solo aislamiento desarolló resistencias a la cefalexina desde 1986 a 1996. No se han encontrado resistencias frente a la asociación amoxicilina-clavulanico, oxicilina, meticilina y enrofloxacina. Se demostró una resistencia superior en los aislamientos a partir de mucosa que aquellos a partir de piel. Diversos aislamientos realizados en 90 perros mostraron espectros de resistencias differentes en 56 por ciento de los casos, lo cual indica que únicamente muestras recogidas a partir de escobillon son de valor limitado a la hora de determinar una terapia antibiótica optima. [Lloyd, D.H., Lamport, A.I., Feeney, C. Sensitivity to antibiotics amongst cutaneous and mucosal isolates of canine pathogenic staphyloccoci in the United Kingdom, 1980–96 (Sensibilidad a los antibioticós entre aislamientos cutanéos y mucosos de estafilococos patogénico en el Reino Unido, 1980–96). Veterinary Dermatology 1996; 7 : 171–175.] Zusammenfassung— Es wurden Resistenztests mit Antibiotika-Plättchen bei 2.296 nicht-pigmentierten, koagulase-positiven Staphylokokken-Stämmen durchgeführt, die von Hunden in einer Überweisungspraxis im Zeitraum von 1980 bis 1996 gewonnen worden waren. 98 Isolate kamen von den Ohren, 1089 von anderen Hautgebieten und 37 von den Schleimhäuten. Resistenzen gegenüber Penizillinen stiegen von 69,0 auf 89, 3%. Resistenzen gegenüber Oxytetracyclin blieben bei etwa 40%; Resistenzen auf Erythromycin bzw. Lincomycin und Co-Trimazole waren in den Jahren 1987 bis 1989 am höchsten mit 20 und 15%, sind seither jedoch weniger geworden. Nur ein einziges Isolat mit Resistenz gegenüber Cephalexin wurde zwischen 1986 und 1996 gefunden. Es zeigte sich keine Resistenz auf Co-Amoxyclaf, Oxacillin, Methicillin und Enrofloxacin. Die Resistenzen von Schleimhaut-Isolaten waren höher als die von der Haut. Mehrfachisolate von 90 Hunden zeigten Spektren mit unterschiedlichen Resistenzen in 56% der Fälle. Dies ist ein Hinweis, daß Einzelabstriche von begrenztem Wert sind, um optimal wirksame Antibiotika zu ermitteln. [Lloyd, D.H., Lamport, A.I., Feeney, C. Sensitivity to antibiotics amongst cutaneous and mucosal isolates of canine pathogenic staphyloccoci in the United Kingdom, 1980–96 (Sensitivität auf Antibiotika bei kutanen und Schleimhaut-Isolaten von pathogenen Staphylokokken des Hundes im Vereinigten Königreich, 1980 bis 1996). Veterinary Dermatology 1996; 7 : 171–175.]     

The role of CD44 adhesion factor in canine mammary carcinomas

CD44 is an adhesion molecule implicated in the progression of human breast cancer. The purpose of this study was to describe CD44 antigen expression in canine mammary carcinomas and to evaluate its prognostic significance in relation to other clinico-pathological variables.A reduction in CD44 expression was significantly related to variables such as tumour size and adherence to underlying tissues but was not related to tumour location or to ulceration of the overlying skin. Complex (grade I) and anaplastic (grade III) carcinomas exhibited more intense expression of this antigen than did some tubulopapillary and most solid carcinomas (grade II). Although reduced CD44 expression was associated with infiltrative growth and vascular invasion in solid carcinomas, intense expression was also observed in anaplastic tumours. Although overall these findings suggest a role for this adhesion factor in canine mammary tumour development and progression, the complexity and apparently paradoxical nature of some of the findings currently limit the use of this immunohistochemical marker as a prognostic indicator.     

Acute primary canine herpesvirus-1 dendritic ulcerative keratitis in an adult dog

We present a report of dendritic ulcerative keratitis in a 4-year old locally immunosuppressed dog suspected to result from acute primary canine herpesvirus-1 (CHV-1) infection. The dog was presented for evaluation of mild blepharospasm and conjunctival hyperemia in the right eye (OD) shortly after attending a public boarding facility. For approximately 3 months, the dog had been receiving topical prednisolone acetate 1.0% and tacrolimus 0.02% in both eyes (OU) q12h for treatment of follicular conjunctivitis. Ophthalmic examination revealed three regions of corneal fluorescein retention OD. The lesions had a dendritic pattern, were approximately 2-3 mm in length, and were located at the dorsomedial, lateral, and ventromedial aspects of the cornea. No additional abnormalities were noted on complete ophthalmic and physical examinations. CHV-1 was identified in conjunctival samples OD by polymerase chain reaction, and paired CHV-1 serum virus neutralization antibody titers were positive and consistent with acute infection. Topical prednisolone acetate and tacrolimus were discontinued. The dog was treated with cidofovir 0.5% OU q12h for a period of 4 weeks, with resolution of corneal disease noted within 1 week of treatment. In conjunction with previous studies, this case report supports a central role for alterations in host immune status in the pathogenesis and clinical manifestations of CHV-1 ocular disease in dogs.     

Major histocompatibility class II expression in the normal canine cornea and in canine chronic superficial keratitis

OBJECTIVE: To compare the expression of major histocompatibility complex (MHC) class II antigen in the corneas of normal dogs and dogs affected with chronic superficial keratitis (CSK). METHODS: MHC class II expression was determined in frozen sections of normal canine cornea and cornea from lesions of CSK by immunohistochemistry using a monoclonal antibody directed against the canine MHC class II molecule. Langerhans cell phenotype was determined morphologically and by histochemical determination of ATPase activity. To determine the influence of gamma interferon on expression of MHC class II molecules by corneal cells, corneal explants were cultured with the cytokine and MHC class II expression determined as above. RESULTS: Numerous MHC class II-expressing cells were demonstrated within the stroma and epithelium of the normal corneal limbus and conjunctival epithelium while very little MHC class II expression was detected in the central region of normal canine cornea. In limbal and conjunctival epithelium, cells expressing MHC class II antigen showed ATPase activity, suggesting that they were Langerhans cells. Corneas from dogs with CSK showed MHC class II expression associated with stromal cells, some of which exhibited a dendritic morphology while most were lymphocytic. Corneal epithelial cells within the lesion also aberrantly expressed MHC class II. Corneal explants expressed MHC class II to varying degrees after differing periods of incubation with the cytokine gamma interferon. CONCLUSIONS: While the normal central cornea has little MHC class II expression, aberrant expression occurs in CSK, associated with secretion of gamma interferon by infiltrating CD4-expressing lymphocytes. Although this change is likely to be a secondary feature of the CSK lesion, increased MHC class II expression may play a part in perpetuating the corneal inflammation seen in the disease.     

Absent expression of collagen XVII (BPAG2, BP180) in canine familial localized junctional epidermolysis bullosa

Hereditary junctional epidermolysis bullosa (JEB) represents a subset of mechanobullous diseases associated with defective hemidesmosome/anchoring filament proteins leading to cleavage in the lamina lucida of the epidermal basement membrane. In humans, most cases of JEB have been related to a deficiency of either laminin-5, collagen XVII (BPAG2, BP180) or integrin β4.
We describe the existence of a previously unreported form of familial localized non-lethal JEB in German Shorthaired Pointer littermates. Acral, auricular and oral erosions and ulcers were observed. Severe ulceration of the footpads was present.
Skin biopsy specimens of non-lesional and lesional skin of affected dogs were screened for a defect in basement membrane proteins using indirect immunofluorescence and immunoperoxidase testing. Epidermal staining for laminin-5 and integrin α6β4 was similar in affected and normal control dogs. Lack of expression of collagen XVII was uniquely identified in all sections of JEB probands compared with normal control dogs.
The defective expression of collagen XVII is likely to be caused by mutation(s) of the COL17A1 gene, as previously reported in humans. This is, to date, the first report of a deficient basement membrane protein in canine JEB.