Patterns of expression of feline cytokeratins in healthy epithelia and mammary carcinoma cells.

Expression of keratins (cytokeratins, CK) in healthy feline epithelia and 2 established feline mammary carcinoma cell lines was examined immunohistochemically and by use of immunoblotting analysis. A panel of specific anti-CK monoclonal antibodies (MAb) identifying epitopes unique to individual keratins or shared by 2 (or 3) CK polypeptides was used. Besides already available anti-human CK MAb, this panel of MAb consisted of 9 newly generated anti-human CK MAb and 1 newly generated anti-feline CK MAb. Immunohistochemical analysis on normal epithelia revealed that most of the anti-human CK MAb and the anti-feline CK MAb reacted with both feline and human epithelia, with a comparable tissue distribution pattern. However, slight differences in CK tissue distribution pattern between human beings and cats were detected by one MAb. Immunoblotting analysis revealed that all anti-human CK MAb that were immunohistochemically reactive with feline tissues detected analogous CK in cats, indicating the presence of a number of common epitopes on human and feline CK. Two continuous cell lines derived from 2 distinct feline mammary adenocarcinomas, K248C and K266, were analyzed with respect to their CK phenotype. Although no difference in CK expression between the 2 cell lines was detected in vitro, a difference in CK phenotype was detected on subcutaneous transplantation of the 2 cell lines into nude mice. Although the K248C-induced adenocarcinomas maintained the same CK phenotype as observed in vitro, the CK pattern of the K266 heterotransplants, growing as adenosquamous carcinomas, changed with squamous differentiation. Our findings confirm the high degree of homology between mammalian CK, and on the basis of those findings, we suggest that CK proteins provide a set of markers valuable for the characterization of normal and neoplastic feline tissues and for studies of squamous metaplasia.     

Calponin expression and myoepithelial cell differentiation in canine, feline and human mammary simple carcinomas

Calponin is a 34‐kDa smooth muscle‐specific protein that has been shown to be a highly sensitive marker of myoepithelial cells in canine, feline and human mammary tissue and tumours. The expression of calponin was studied in 15 canine, 32 feline and 28 human simple mammary carcinomas using a monoclonal mouse antihuman calponin antibody and the avidin–biotin peroxidase complex (ABC) immunohistochemical technique. Calponin expression was compared with the expression of cytokeratin 14, a marker of normal mammary myoepithelial cells in the three species. Four different types of calponin‐positive cells were identified: (1) Type 1: cytokeratin‐14‐positive pre‐existing myoepithelial cells forming a continuous layer with images of focal disruptions; (2) Type 2: cytokeratin‐14‐positive isolated nests of fusiform, polygonal or round cells without atypia; (3) Type 3: cytokeratin‐14‐positive atypical cells indistinguishable from non‐reactive atypical cells, which should have never been detected in haematoxylin and eosin‐stained sections and (4) Type 4: cytokeratin‐14‐negative stromal fusiform cells around the neoplastic growth or cell nests, identified as myofibroblasts. Calponin‐negative and cytokeratin‐14‐positive atypical neoplastic cells were observed in three canine, 28 feline and two human carcinomas. The latter were indicative of altered expression of high‐molecular‐weight cytokeratins in luminal epithelial‐type simple carcinomas. Our findings show that calponin is a good marker of myoepithelial cell differentiation in feline, human and, particularly, canine simple carcinomas. The high number (six out of 15) of canine tumours with type 3 cells points to the need of both introducing calponin examination in the routine diagnostic schedule and performing further studies on its prognostic significance.     

Immune-mediated canine and feline keratitis.

Although the normal cornea is devoid of vasculature and lymphatics, there are still several immune-mediated corneal conditions that can occur in dogs and cats. An overview of corneal immunology is presented. Diseases of dogs, including chronic superficial keratitis, superficial punctate keratitis, and canine adenovirus endotheliitis, as well as feline diseases, including eosinophilic keratitis and herpesvirus-related conditions, are discussed.     

Immunohistochemical evaluation of intermediate filament expression in canine and feline neoplasms

Specimens of neoplastic tissues from 19 dogs and 4 cats were examined immunohistochemically for intermediate filament expression, using commercially available antibodies. Staining was observed in a wide range of tumor tissues and in normal internal controls by use of antibodies to vimentin, desmin, glial fibrillary acidic protein, and low and high molecular weight cytokeratins. Intermediate filament expression was found to be consistent with light and/or electron microscopic findings, and hence believed to be an accurate indicator of tumor histogenesis in cats and dogs. Three fixatives were evaluated for their relative abilities to preserve antigenicity. Absolute alcohol was superior to B5 fixative and both were superior to formalin. Some tissues that clearly displayed intermediate filament antigens with alcohol and B5 fixative failed to stain when fixed in formalin.     

The expression of calretinin and cytokeratins in canine acanthomatous ameloblastoma and oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) and canine acanthomatous ameloblastoma (CAA) represent two epithelium‐derived neoplasms that affect the oral cavity of dogs. The expression of cytokeratins (CKs) and calretinin has been previously established in the canine tooth bud and odontogenic tumours. The aim of this study was to characterize the CK and calretinin expression profile of OSCC in comparison to CAA and canine tooth bud tissues. Samples from 15 OSCC and 15 CAA cases, as well as 6 tooth buds and 2 normal gingival tissues were examined. OSCC CK expression was consistent with the CK expression profile of CAA and canine tooth bud tissue. Calretinin was positively expressed in 10 of 15 OSCC cases, with 5 cases demonstrating high staining intensity. Only 2 of 15 CAA cases demonstrated mild‐moderate staining intensity. The statistically significant difference in staining pattern and intensity of calretinin in OSCC and CAA can help distinguish between these two tumour types.     

Current research in canine and feline pheromones.

Pheromonotherapy seems to be a new therapeutic approach allowing practitioners to tackle the treatment of behavioral disorders in a natural, specific, and safe way. Although the efficacy of pheromones has been assessed in some specific behavioral problems, it seems that their range of action could cover the wide field of reduction of stress. Therefore, the use of pheromones should not be reduced to treatment of behavioral disorders (potentially associated with psychotropes or a behavioral modification program) but should be included in a strategy of improving the welfare of pets in veterinary structures (during examination and hospitalization) and in breeding networks (separation from the mother and transport). Moreover, further studies may allow the veterinary practitioner to use pheromone analogues in the field of diagnostics to determine the behavioral status of a pet (e.g., anxious or not, dominant or not). Pheromonotherapy is at its beginning, and the use of pheromones in various fields of medicine is heartening.     

Immunohistochemical expression of cyclooxygenase-2 in canine ovarian carcinomas

Ovarian tumours among domestic animals are frequently encountered in bitch. Cyclooxygenase-2 (COX-2) expression has been evaluated in different kind of canine primary epithelial neoplasms. Eleven canine ovarian carcinomas and two normal samples were evaluated immunohistochemically for COX-2 expression. Nine of 11 carcinoma samples (81%) expressed COX-2 enzyme isoform. The immunoreactivity was intracytoplasmically recorded and the intensity ranged from faint to strong. Our results show that COX-2 is expressed in canine ovarian carcinoma, suggesting a potential role of COX-2 in canine ovarian carcinogenesis.     

Epidermal growth factor receptor expression in feline oral squamous cell carcinomas

Feline oral squamous cell carcinomas (SCC) have a poor prognosis despite aggressive treatment with surgery, radiation and anticancer drugs. Overexpression of the epidermal growth factor receptor (EGFR), a membrane‐bound tyrosine kinase receptor, has been found in many human epithelial neoplasms, including oral SCC. EGFR overexpression has been associated with advanced disease and a poor prognosis. The purpose of this study was to determine whether feline oral SCC express EGFR. Thirteen formalin‐fixed paraffin wax‐embedded biopsy samples from feline oral SCC were analysed for EGFR expression using immunohistochemistry. Nine of 13 tumours (69%) were positive for EGFR expression, suggesting that altered EGFR expression plays a role in feline oral SCC and provides a rationale for a potential clinical benefit using EGFR inhibitors in combination with conventional treatments.     

Update on canine and feline fungal diseases.

Systemic fungal diseases cause significant morbidity and mortality in dogs and cats. Blastomycosis, histoplasmosis, coccidiomycosis, and cryptococcosis represent the four most common systemic fungal diseases. Young adult, large breed dogs generally are predisposed; cats usually do not have predictable predispositions. Intact cell-mediated immunity is essential to initial resistance to infection and response to treatment in animals. Several body systems can be affected. Diagnosis can be confirmed on the basis of clinical signs and demonstration of the causative organism. Serology is helpful with coccidiomycosis and cryptococcosis. Treatment is complicated by limited availability of fungicidal antimicrobials and the necessity of long-term treatment with expensive drugs.     

CD20 expression in normal canine B cells and in canine non-Hodgkin lymphoma

We examined the expression of CD20 in normal canine peripheral blood mononuclear cells, normal canine spleen, and canine non-Hodgkin lymphoma (NHL) to determine the feasibility of using this antigen as a diagnostic aid and as a possible target for therapy. An antibody generated against a C-terminal (intracytoplasmic) epitope of human CD20 recognized proteins of 32-36 kd in normal and malignant canine lymphocytes. This antibody showed restricted membrane binding in a subset of lymphocytes in peripheral blood, in the B-cell regions from a normal canine spleen and lymph node, and in malignant cells from 19 dogs with B-cell NHL, but not from 15 dogs with T-cell NHL. The patterns of CD20 reactivity in these samples overlapped those seen using an antibody that recognizes canine CD79a. This anti-CD20 antibody is therefore suitable as an aid to phenotype canine NHL. In contrast, normal canine B cells were not recognized by any of 28 antibodies directed against the extracellular domains of human CD20 (including the chimeric mouse-human antibody Rituximab) or by any of 12 antibodies directed against the extracellular domains of mouse CD20. Thus, the use of CD20 as a therapeutic target will require the generation of specific antibodies against the extracellular domains of canine CD20.     

Dietary effects on canine and feline behavior.

The effects of dietary deficiency, including both malnutrition and deficiency of specific vitamins, on behavior is discussed with special emphasis on the growing kitten and puppy. The effect of caloric restriction on behavior is reviewed so that owners can be advised what to expect when their dog is placed on a reducing diet. The evidence for influence of dietary protein and tryptophan on canine aggression is presented. The effect of special diets on canine cognitive dysfunction is reviewed.     

Basics in canine and feline rhinoscopy

Patients suffering from upper respiratory disease such as chronic nasal congestion, sneezing, nasal discharge, and epistaxis invite complete evaluation of their paired nasal cavities. Thorough assessment of these cavities employs sundry diagnostic procedures that enable the investigating clinician to characterize the internal structures of the nasal cavities. After the conscious patient undergoes a complete physical examination, a gross assessment of its external nasal structures is established and areas of physical asymmetry are noted. A working anatomic knowledge of these asymmetric foci helps to guide the next diagnostic steps. The patient is then placed under general anesthesia, during which, in list order, imaging studies, rhinoscopy, and nasal biopsy or foreign body retrieval, are performed.     

The expression of sialyl Lewis X in canine and feline mammary gland tumors

The expression of sialyl Lewis X (sLe(x)) in 93 canine and 15 feline mammary gland tumors (MGT) obtained by surgical resection at Veterinary Medical Center, the University of Tokyo was examined by immunohistochemistry. Their clinicopathological features and prognosis were also reviewed. Approximately 60% of MGT tissues showed sLe(x) positive expressions, while all normal mammary gland tissues were negative. However, its expression was not correlated with clinicopathological features and prognosis significantly. This study suggests that sLe(x) may be a tumor-associated antigen in canine and feline MGTs.     

Diagnostic imaging of the canine and feline ear.

Radiographic evaluation of the tympanic bulla is limited. Improper obliquity or angulation of the skull for radiographs or malpositioning of the tongue can result in an inadequate study [4]. Additionally, because of the complex anatomy of the canine and feline skull, with superimposition of multiple osseous structures, radiography can result in false-negative examinations or understimation of the disease present [2]. When compared with surgical findings of 19 clinical cases of presumptive middle ear disease, false-negative radiographic findings were found in 25% of the surgically confirmed cases of otitis media [4]. Therefore, radiographs are not considered to be a highly sensitive mode of diagnosing otitis media. Radiographs may be helpful in determining lysis associated with neoplasia; however, the extent of involvement is still underestimated. In a study comparing CT and radiographic evaluation of otitis media, CT was determined to be more sensitive but less specific than radiography [11]. CT is the preferred modality for the evaluation of the tympanic bulla at our institution. This opinion may be biased by the fact that most cases are presented for recurrent or chronic otitis. Although radiography is more accessible, the availability of CT in local referral settings is increasing as opposed to being limited to university settings. After the cost (i.e., anesthesia, radiographs) and amount of time necessary to make optimum radiographic studies are taken into account, a CT study may actually be faster and more informative. Given our preference for the CT examination, the cost of the examination has been adjusted to make it more appealing to the owner and clinician. For example, a bulla CT study is only 1.3 times the cost of a radiographic bulla study. In conclusion, imaging of the ear canal can provide important information about ear disease, including unilateral or bilateral ear disease, the degree of middle or inner ear involvement, peripheral versus central vestibular disease, an infectious or inflammatory versus neoplastic process, the chronicity of the disease process, involvement of adjacent structures, and postsurgical complications.     

Addressing canine and feline aggression in the veterinary clinic.

Handling aggressive dogs and cats in the veterinary clinic can be frustrating, time consuming, and injurious for both employee and animal. This article discusses the etiology of the aggressive dog and cat patient and how best to approach these cases. A variety of handling techniques, safety products, and drug therapy are reviewed.     

Frequency of canine and feline tumors in a defined population.

The Tulsa Registry of Canine and Feline Neoplasms was the second animal tumor registry in the United States concerned with a defined population in a delimited geographic area. Only tumors histologically confirmed by registry pathologists were included in frequency statistics based on the annual dog and cat population presented to veterinarians. During the first registry year, about 1% of the 63,504 dogs and 0.5% of the 11,909 cats had one or more primary tumors. While the incidence rate for malignant tumors in dogs was similar to that in cats, the incidence of benign tumors of dogs was over 10 times that of cats. The most common tumors were sebaceous adenoma in dogs and lymphosarcoma in cats. Mammary cancer was the most common malignant tumor in dogs. Mammary tumors of female dogs were significantly more frequent in Pointers, Poodles and Boston Terriers, in that order, than in other breeds. A greater incidence of mammary tumors among intact compared to spayed female dogs was seen for virtually every age group except in the Pointer breed.