p53 expression and apoptosis in melanomas of dogs and cats

Twenty-seven melanocytic tumours from 20 dogs and four cats were examined for p53 expression and apoptosis. They included tumours that were histologically classified as benign (BM), primary malignant (PMM) and metastatic malignant melanomas (MMM). For all cases clinical follow-up was available. p53 expression was examined immunohistochemically using different monoclonal and polyclonal antibodies. Apoptosis was detected using the TUNEL technique. The tissue sections were analysed using a quantitative image analysing system. A p53 index (p53I) and an apoptotic index (AI) were determined. p53 over-expression was found infrequently in these canine and feline melanocytic tumours. Apoptosis was observed in some of the malignant tumours. In one feline case of malignant melanoma, p53 accumulation together with apoptosis was seen in three metastases but not in the primary tumour. p53I and AI were not significantly correlated with survival. These results are similar to those reported for human cutaneous melanomas.     

Lack of detection of feline leukemia and feline sarcoma viruses in diffuse iris melanomas of cats by immunohistochemistry and polymerase chain reaction.

Diffuse iris melanoma was confirmed by light-microscopic examination in 10 formalin-fixed, paraffin-embedded globes from 10 cats. To determine if feline leukemia virus or a replication defective feline leukemia virus, feline sarcoma virus, was present in these anterior uveal melanomas, immunohistochemistry and polymerase chain reaction for feline leukemia virus were utilized. Immunohistochemical staining for feline leukemia virus glycoprotein 70 was performed on all 10 tumors using an avidin-biotin complex technique. The DNA was extracted from each specimen and a 166-base pair region of the feline leukemia virus long terminal repeat was targeted by polymerase chain reaction. Immunohistochemical staining for feline leukemia virus glycoprotein 70 and polymerase chain reaction amplification of a feline leukemia virus long terminal repeat region were negative in all cases. Feline leukemia virus/feline sarcoma virus was not detected in any neoplasms and therefore was unlikely to play a role in the tumorigenesis of these feline diffuse iris melanomas.     

A matched observational study of survival in cats with enucleation due to diffuse iris melanoma

Although a small number of cases of feline diffuse iris melanoma have been documented to metastasize, the prognosis is not known. In this matched observational study, the survival time of 34 cats with enucleation due to histologically confirmed diffuse iris melanoma was recorded. These results are compared to the survival times of 83 age-matched control cats. Affected cats had enucleation between 2 and 10 years prior to the study. One group of control cats with eye disease had enucleation for either lymphoplasmacytic uveitis (27 cases), ocular trauma (seven cases), or endophthalmitis (four cases). In these control cats, enucleations were performed between 2 and 10 years prior to this study. Forty-five additional control cats presented for vaccination between 2 and 10 years prior to the study. The extent of diffuse iris melanoma at the time of enucleation in affected cats was graded according to the extent of involvement of ocular tissues and the invasiveness of the tumor. Affected cats have a significantly decreased survival compared with control cats and cats with extensive tumors at the time of enucleation have the lowest survival rates. Cats with tumors confined to the iris survive at the same rate as controls. These results suggests that early enucleation is important to avoid premature death, presumed to be due to cancer metastasis in cats with diffuse iris melanoma.     

Classification of feline intraocular neoplasms based on morphology, histochemical staining, and immunohistochemical labeling

The objectives of this study were to evaluate morphologic, histochemical, and immunohistochemical characteristics of well-differentiated and anaplastic intraocular neoplasms of cats, and to develop a diagnostic algorithm for, and investigate the association of ruptured lenses with these neoplasms. Seventy-five feline globes with intraocular neoplasms were stained with hematoxylin and eosin and examined by light microscopy. Morphologic diagnoses included 33 intraocular sarcomas, 17 diffuse iris melanomas, 15 lymphosarcomas, three ciliary adenomas, one metastatic carcinoma, and six undifferentiated intraocular neoplasms. Sections of these globes were then stained with periodic acid Schiff (PAS), and immunohistochemical (IHC) labels for various cellular markers. Histochemical staining and IHC labeling confirmed cellular differentiation in 73/75 neoplasms but was discordant with morphologic diagnoses in 8/75. These included four neoplasms morphologically diagnosed as lymphosarcomas but which expressed differentiation antigens consistent with melanoma (n = 3) or ciliary adenocarcinoma (n = 1), and four tumors morphologically diagnosed as intraocular sarcomas that expressed differentiation antigens for melanoma (n = 2), metastatic carcinoma (n = 1), or remained undifferentiated (n = 1). Immunohistochemical labeling suggested a diagnosis in 5/6 morphologically undifferentiated neoplasms including one intraocular sarcoma, two diffuse iridal melanomas, and two ciliary adenocarcinomas. Based upon morphologic, histochemical, and IHC characterization, ruptured lens capsules were detected in 28/30 intraocular sarcomas, 3/24 diffuse iris melanomas and 1/11 lymphosarcomas, but not in ciliary epithelial neoplasms, metastatic carcinomas, or undifferentiated intraocular neoplasms. An algorithm is provided that facilitates stain and IHC label selection for differentiating anaplastic intraocular feline neoplasms.     

Understanding feline heartworm infection: disease, diagnosis, and treatment

Feline heartworm disease is a very different clinical entity from canine heartworm disease. In cats, the arrival and death of immature heartworms in the pulmonary arteries can cause coughing and dyspnea as early as 3 months postinfection. Adult heartworms suppress the function of pulmonary intravascular macrophages and thus reduce clinical disease in chronic feline heartworm infection. Approximately 80% of asymptomatic cats self-cure. Median survival time for symptomatic cats is 1.5 years, or 4 years if only cats living beyond the day of presentation are considered. Aberrant worm migration is more frequent than it is in dogs, and sudden death can occur with no prior clinical signs. The bacterial endosymbiont Wolbachia likely contributes to the inflammatory pathology of heartworm disease, but its role is not yet fully clear. Unfortunately, the diagnosis, treatment, and management of feline heartworm disease are far from simple. Antemortem diagnosis is hampered by low worm burdens, the frequency of all-male infections, and nonspecific radiographic lesions. It is up to the veterinarian to determine the correct index of suspicion and choose the right combination of diagnostic tests to achieve an answer. Treatment is symptomatic because adulticide therapy is risky and does not increase survival time. Despite the dangers of feline heartworm disease, less than 5% of cats in the United States are on chemoprophylaxis. It is important for veterinarians to take a proactive preventive stance because heartworm infection in cats is a multisystemic disease that has no easy cure.     

Feline melanoma: a comparative study of ocular, oral, and dermal neoplasms

Melanomas diagnosed in 29 cats over an 11 year period included 19 ocular (16 intraocular, three palpebral), five oral, and five dermal melanomas. Intraocular melanomas involved the ciliary body and iris in 12; the whole eye was involved in four. The average age of cats with intraocular melanomas was 11 years; the female : male ratio was 9 : 7. Histologically, eight intraocular tumors were mixed, six were epithelioid, and two were spindle cell. Ten of 16 cats (62.5%) with intraocular melanomas were killed because of the tumor at a mean of 156 days; four are living with no evidence of disease (average, 255 days). The mean time of death in cats with palpebral melanoma was 409 days. Metastasis occurred in 63% of cats with intraocular melanoma and all cats with palpebral melanoma. Four cats with oral melanoma were killed at a mean of 61 days; all had metastasis. Of five cats with cutaneous melanoma, one was killed with metastasis at 90 days; three cats were alive without evidence of recurrence or metastasis greater than 365 days after surgery. Results of this study indicate that in the cat, ocular melanomas are more common than oral and dermal melanomas, and ocular and oral melanomas are more malignant than dermal melanomas, with higher rates of mortality and metastasis.     

Feline hippocampal and piriform lobe necrosis as a consequence of severe cluster seizures in two cats in Finland

Feline hippocampal and piriform lobe necrosis (FHN) has been reported from several countries worldwide and is considered an important aetiology for feline epileptic seizures. The aetiology of FHN remains unclear, however it is suspected that FHN might occur secondary to intense epileptic activity as described in humans and dogs although this has not yet been documented in cats. The purpose of our report is to describe the first cases of FHN in Finland diagnosed by magnetic resonance imaging (MRI) and histopathology. The two cases we describe had a well documented history of pre-existing seizures with normal brain MRI at the onset of cluster seizures but MRI done when the cats exhibited clinical deterioration secondary to severe seizure activity, revealed lesions in the hippocampus and piriform lobes typical of FHN. Our report confirms that feline hippocampus and piriform lobe necrosis does occur in the Finnish cat population and should therefore be considered as a differential diagnosis in cats with seizures. In addition, the presentation, clinical findings, results of MRI and/or histopathology shows that cats may develop FHN secondary to severe seizure activity.     

Evaluation of a novel nested PCR for the routine diagnosis of feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV)

Laboratory diagnosis of feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) usually involves both viruses, as the clinical signs are similar and coinfection may occur. Serological methods may not represent an accurate diagnosis: maternal antibodies or cross-reactions may give false positive results to FIV, and false negative results may occur in latent FeLV status, or in certain FIV infection stages. A nested polymerase chain reaction (PCR) technique was designed to detect FeLV, FIV and feline endogenous retrovirus simultaneously. The detection of endogenous sequences was considered indicative of successful DNA extraction. The technique was used to diagnose FIV and FeLV in the blood cells of 179 cats. The kappa value with the serological data was 0.69 for FeLV and 0.87 for FIV. The joint detection of FeLV and FIV by this novel nested PCR is sensitive, specific, fast and convenient, and its applicability for clinical diagnosis is promising, as the direct evidence of the presence of the virus is more realistic than the indirect data provided by the serological detection.     

One‐year conditional survival of dogs and cats with invasive mammary carcinomas: A concept inspired from human breast cancer

Numerous studies have described the prognostic factors of canine and feline mammary carcinomas (MCs), that is, variables that predict patient survival after diagnosis. But how does survival estimation evolve in patients that escaped early death from their cancer? In human oncology, conditional survival (CS), the probability of surviving X further years when cancer patients have already survived Y years, is used to analyse cancer outcomes in a long‐term perspective. In this cohort of 344 dogs and 342 cats with surgically removed stage I to III invasive MCs, with a minimal follow‐up of 2 years, we calculated the 1‐year CS, that is, the probability for patients that have survived 1 year, to survive or to die from cancer during the subsequent year. The 1‐year conditional specific survival probabilities were 59% and 48% at diagnosis of invasive MC respectively in dogs and cats, and 80% and 52% in 1‐year surviving dogs and cats respectively, suggesting that 1‐year surviving dogs were relatively protected from cancer‐related death, whereas feline MCs remained life‐threatening cancers for longer periods of time. Among the most significant parameters associated with CS in surviving dogs and cats were the nodal stage and lymphovascular invasion, as well as patient age, cancer stage and margin status in surviving dogs. By comparison, tumour size and the histological grade did not significantly alter CS probabilities in surviving dogs and cats. Conditional survival may be considered a very interesting tool for veterinary practitioners to estimate the likely outcome of cancer survivors.     

Clinical, hematologic, and survival data from cats infected with feline immunodeficiency virus: 42 cases (1983-1988).

A retrospective study of stored feline serum samples was done to determine the infection rate of feline immunodeficiency virus in cats in central Missouri. Infected cats were compared with uninfected cats subjected to the same selection criteria on the basis of signalment, clinical signs, and CBC abnormalities. A significant incidence of virus infection was found in male cats. Neither age nor breed predilection could be identified. Infected cats were more likely to be anemic and leukopenic because of neutropenia. Cellulitis and neoplasia were more common in infected cats. A spectrum of disease severity was seen in infected cats ranging from no clinical signs to signs of severe chronic inflammatory disease. Infected cats were more likely to have clinical disease. Mean survival of infected cats was 24.4 months from the time of diagnosis.     

Malignant melanoma in pleural effusion in a 14-year-old cat

CASE DETAILS: A 14-year-old female cat presented with signs of respiratory distress. Pleural fluid was found on radiographic assessment. Cytologic evaluation of the fluid revealed malignant melanocytosis. The cat had a previous history of a recurrent malignant melanoma near the base of the right ear. Due to declining clinical condition, the cat was euthanized. CLINICAL SIGNIFICANCE: Cutaneous malignant melanomas (or melanosarcomas) are uncommon neoplasms in cats, and knowledge is limited. As far as the authors are aware, there are no previous reports in the veterinary literature of malignant melanocytes being identified in pleural effusion in cats, as they have in dogs. This report suggests that, despite conflicting information in the literature regarding the clinical behavior of cutaneous melanomas in cats, these tumors are capable of recurrence and metastasis. Aggressive treatment may be necessary even, as in this case, if the tumor is well differentiated on histopathology.     

Clinical features, survival times and COX-1 and COX-2 expression in cats with transitional cell carcinoma of the urinary bladder treated with meloxicam

Records of 11 cats with transitional cell carcinoma of the urinary bladder, which had been treated with meloxicam, were reviewed for signalment, duration of clinical signs prior to diagnosis, results of diagnostic imaging, whether or not concurrent surgery was performed and survival. Immunohistochemical expression of cyclo-oxygenase-1 (COX-1) and cyclo-oxygenase-2 (COX-2) was assessed in the tumours of seven cats. Tumour location varied greatly. The cats had a mean age of 13 years. Three cats had a previous diagnosis of feline idiopathic cystitis of up to 2008 days duration. Ten of the cats showed clinical improvement (reduction of haematuria and/or dysuria), with a mean survival time (MST) of 311 days (range 10-1064); 1-year survival of 50%. All seven bladders assessed for COX staining were COX-1 positive and five were COX-2 positive. The MST for the COX-2-positive cats was 123 days, the MST for the COX-2-negative cases was 375 days.     

Evaluation of P-glycoprotein expression in feline lymphoma and correlation with clinical outcome

P-glycoprotein (Pgp) is a transmembrane protein pump involved in drug resistance in canine and human lymphoma. There are no published clinical studies evaluating Pgp expression in feline lymphoma. The purpose of this study is to evaluate the level of Pgp expression in feline lymphoma and correlate it with clinical outcome. Two human Pgp monoclonal antibodies, C219 and C494, were used to detect Pgp expression in tissue samples from 63 cats with lymphoma. Demographic results appear comparable to recently published feline lymphoma studies. The Kaplan–Meier median remission and survival times were 164 and 571 days, respectively. Fourteen cats had positive expression of Pgp using MAb C219, and 40 were positive with C494. Variables statistically associated with survival included bone marrow involvement, stage, substage, and use of radiation therapy as a part of treatment. Pgp expression as assessed by MAb C219 and C494 is not predictive of remission or survival time in cats with lymphoma.     

Prevalence study of the lungworm Aelurostrongylus abstrusus in stray cats of Portugal

In this study we have investigated the prevalence of aelurostrongylosis, one of the most common feline pulmonary parasitic diseases, in cats from the north-west region of Portugal. For this purpose, 97 faecal samples were collected from cats at risk of being infected by Aelurostrongylus abstrusus in an animal shelter and in a municipal facility. Using the Baermann-Wetzel coprological technique, faecal shedding of first stage larvae (L1) was detected in 17.4% of the cats. Based on this result, it can be concluded that this lungworm infection seems to be common among feral cats in the north-west region of Portugal, in spite of the fact that clinical aelurostrongylosis is not frequently diagnosed by feline practitioners in the area. This parasitic disease should be included in the differential diagnosis of cats presenting with coughing or dyspnoea, and it also should be extended to asymptomatic animals with pulmonary nodules detected by image diagnosis.     

Aortic stenosis: clinical findings in six cats

Congenital aortic stenosis was diagnosed in six cats. Clinical findings included dyspnoea, systolic murmurs with maximal intensity at the left apex or right sternal border, and cardiomegaly with congestive heart failure. Some clinical features of feline aortic stenosis were similar to those observed in cats with hypertrophic cardiomyopathy. Definitive diagnosis was obtained by angiographic imaging of a discrete, consistent subvalvular obstruction, Doppler-echocardio-graphy, or by necropsy. Although, two of the cats were diagnosed at ages older than usually reported, the overall prognosis for cats with aortic stenosis was poor. Four of the six cats died or were euthanased within one year of the onset of clinical signs.     

Effect of feline interferon-omega on the survival time and quality of life of cats with feline infectious peritonitis

BACKGROUND: There is no therapy with proven efficacy to treat cats with feline infectious peritonitis (FIP). HYPOTHESIS: Feline interferon-omega (FeIFN-omega) prolongs survival time and increases quality of life in cats with FIP. ANIMALS: Thirty-seven privately owned cats were subjects of this study. METHODS: The study was performed as a placebo-controlled double-blind trial. Feline infectious peritonitis was confirmed by histology or immunostaining of feline coronavirus (FCoV) antigen in effusion or tissue macrophages or both. The cats were randomly selected for treatment with either FeIFN-omega or a placebo. All cats received adjunctive treatment with glucocorticoids and antibiotics and passive immunization with Feliserin. RESULTS: There was no statistically significant difference in the survival time of cats treated with FeIFN-omega versus placebo or in any other variable evaluated (with the exception of the lymphocyte count). The cats survived between 3 and 200 days (median, 9 days). There was only 1 long-term survivor (> 3 months), and the cat was in the FeIFN-omega group. CONCLUSION AND CLINICAL RELEVANCE: No effect of FeIFN-omega on survival time or quality of life could be demonstrated in this study.     

The diagnostic significance of a positive direct antiglobulin test in anemic cats.

The preparation of a feline Coombs serum (rabbit antifeline gamma globulin) is described. The direct antiglobulin test using this serum was performed on 20 anemic and 20 healthy control cats. Red cell membrane antibodies were detected in cats with feline leukemia virus infection and in others with inflammatory and neoplastic diseases. A low titre of cold agglutinating antibody was present in a high proportion of the control cats. Positive direct antiglobulin tests were noted in cats without overt hemolytic disease. It was concluded that the direct antiglobulin test in anemic cats has certain diagnostic limitations. A positive reaction should be interpreted cautiously especially when there is no clinical or laboratory evidence to support a diagnosis of autoimmune hemolytic anemia.