Clinicopathological features of seven cases of canine myelofibrosis and the possible relationship between the histological findings and prognosis.

Seven dogs with non-regenerative anaemia were diagnosed as having myelofibrosis on the basis of the presence of collagen and increased deposits of reticulin fibre in the haemopoietic spaces of bone marrow core biopsies. A scoring system was used to assess the cellularity of the marrow and the amounts of collagen, reticulin and haemosiderin present. These scores, together with the haematological findings, were compared with the dogs' responses to treatment and their outcome. Treatment consisted of blood transfusions, where required, and anabolic steroids and corticosteroids. Three dogs deteriorated and were euthanased within three months of diagnosis, but the other four recovered fully. There was no correlation between the collagen and reticulin scores, or the degree of anaemia and the outcome, but the four dogs which recovered all had a macrocytosis when first examined. There was no evidence of an underlying lymphoproliferative or myeloproliferative disease in any of the seven cases.     

Myeloproliferative disorder involving the megakaryocytic line

Myeloproliferative disorders involving the megakaryocytic line are uncommon but in recent years several reports have come from North America and the United Kingdom describing megakaryoblastic leukaemia (MbL) and a particular form called essential thrombocythaemia (ET). This article reports a myeloproliferative disorder in a dog that was ultimately designated as MbL on the basis of the presence of circulating blast cells and thrombocythaemia, and of multi-organ infiltration and myelofibrosis. It comments on the difficulties of diagnosing such a condition and reviews previously published articles on MbL and ET in dogs and cats.     

Hypertrophy of intestinal smooth muscle in cats

Pathological findings of four cats with severe and diffuse smooth muscle hypertrophy of the small intestine (MHSI) are reported and compared to those of five cats with segmental MHSI secondary to neoplastic obstruction and four controls. Histology demonstrated a constant association between idiopathic MHSI and submucosal fibrosis and chronic lymphoplasmacytic enteritis. Morphometry (gut diameter, thickness and area of muscular layers, number and density of smooth muscle nuclei) and MIB-1-immunolabelling showed that the thickness increase was mostly due to hypertrophy, but hyperplasia was also evident. Microbiology from ileal content samples was performed in two cats with primary MHSI, and Campylobacter spp. were isolated, which were also demonstrated by immunohistochemistry and ultrastructure. The association of chronic enteritis with idiopathic MHSI suggests that factors released in intestinal inflammation may also act as hypertrophy stimuli for smooth muscle cells.     

Surgical cytoreduction for the treatment of non-lymphoid vertebral and spinal cord neoplasms in cats: retrospective evaluation of 26 cases (1990–2005)

Medical records of 26 cats with non‐lymphoid vertebral and spinal cord neoplasms treated surgically were reviewed to determine outcome and prognostic factors for survival. Of the factors examined, only tumour phenotype was significantly associated with survival. Osteosarcoma (3/26 cats) and meningioma (16/26 cats) were the most common malignant and benign tumours, respectively. The median survival time for cats with malignant neoplasms was 110.5 days, compared with 518 days for cats with benign tumours. Cytoreductive surgery resulted in clinical improvement in 25/26 cats, but local treatment failure occurred in 10/26 cats. Overall, 19/26 cats died of confirmed (12/19) or suspected (7/19) tumour‐related causes, including all eight cats with malignant neoplasms. Results suggest that contemporary neurosurgical techniques commonly result in incomplete excision of feline non‐lymphoid vertebral and spinal cord tumours but are efficacious at palliation of clinical signs of spinal cord dysfunction.     

The influence of diet and other factors on owner-perceived obesity in privately owned cats from metropolitan Perth, Western Australia.

A randomly selected group of cat-owning households (n = 458) were interviewed to determine the diet of their cats (n = 644) in the week prior to the survey and to identify dietary and other factors which were associated with obesity. All cats were categorised by their owners as underweight, correct-weight or overweight and the weight of 127 cats was also recorded. Nearly all cats were fed commercially prepared dry pet food (90.5%) or canned pet food (84.6%) in the week prior to the survey. Nineteen percent of cats were classified as overweight. Although the make-up of a cat's diet was found not to be associated with its weight or weight category, cats fed dietary supplements or those which had not received a specific kitten diet when <6 months of age were more likely to be overweight after univariable analysis. Logistic multiple regression was used to investigate the effect of putative risk factors on obesity while controlling for other factors. Overweight cats were more likely to be cross-bred (OR = 2.1), neutered (OR = 2.8), living in houses with only one or two cats (OR = 1.8), male (OR = 1.4) and predominantly confined inside a house (OR = 1.4). Obesity is influenced by a variety of factors including host, dietary and management factors and these must be considered when developing weight control programmes for cats.     

Outcome of cats with low-grade lymphocytic lymphoma: 41 cases (1995-2005)

OBJECTIVE: To evaluate factors associated with response to treatment, remission duration, and survival in cats with low-grade lymphoma affecting various organ systems. DESIGN: Retrospective case series. Sample POPULATION: 41 cats with histologically confirmed low-grade lymphocytic lymphoma. PROCEDURES: Medical records and biopsy specimens of cats with histologically confirmed low-grade lymphocytic lymphoma of various organ systems treated with prednisone and chlorambucil between 1995 and 2005 were reviewed. The Kaplan-Meier method was used to estimate remission duration and survival. Factors potentially associated with prognosis were compared. RESULTS: Common clinical signs were weight loss (83%), vomiting (73%), anorexia (66%), and diarrhea (58%). Seventy-eight percent of cats tested had low serum cobalamin concentrations. Lymphoma was confined to the gastrointestinal tract in 68% of cats. Fifty-six percent of cats achieved a complete response to treatment, and 39% achieved a partial response. Five percent of cats had no response. No association was found between any risk factors (including anatomic site) and response to treatment. Partial response was associated with shorter remission duration, compared with complete response; median remission duration was 428 days for cats achieving a partial response, compared with 897 days for cats achieving a complete response. No other factors were associated with remission duration. Overall median survival time was 704 days. No factors were significantly associated with survival time. CONCLUSIONS AND CLINICAL RELEVANCE: Most cats with lymphocytic lymphoma responded to treatment with prednisone and chlorambucil, and most factors evaluated were not associated with outcome.     

Survival,Complications, and Analysis of Risk Factors after Renal Transplantation in Cats

Objective— To report survival, complications, and analyze risk factors for survival after renal transplantation (RTr) and cyclosporine‐A based immunosuppression in cats. Study Design— Historical cohort. Animals— Cats (n=60). Methods— Data were obtained from medical records of cats that had RTr. Influence of various perioperative factors on survival and complications was evaluated. Occurrence of postoperative hypertension (HT), seizures, infection, acute allograft rejection (AR), congestive heart failure (CHF), and delayed graft function (DGF) was evaluated. Results— Survival to discharge after RTr was 77.5%. Estimated median overall survival time was 613 days; 6 month and 3 year overall survival proportions were 65% and 40%, respectively. Age, weight, and blood pressure influenced overall survival. Increased preoperative creatinine concentration, blood urea nitrogen, postoperative creatinine concentration, left ventricular wall thickness, and reduced creatinine reduction ratio influenced survival until discharge. HT was identified in 9/30 (30%) cats; however, no risk factors were identified, nor was HT related to seizures. AR was identified in 8/62 (13%) grafts. Infection, predominantly bacterial, developed in 22/60 (37%) cats. CHF occurred in 7/60 (12%) cats before discharge. Cats experiencing CHF were younger, had an increased incidence of heart murmurs, and poor initial graft function. DGF was identified in 5 cats and seizures in 2 cats. Conclusions— RTr affords cats with CRF long survival times. Older cats and cats with severe azotemia, HT, and cardiovascular disease may have increased mortality after RTr. Complications after RTr were common. Clinical Relevance— Clinicians should be aware of these risk factors when recommending feline RTr.     

Separation of serum glycated proteins by agarose gel electrophoresis and nitroblue tetrazolium staining in diabetic and normal cats

BACKGROUND: The total glycated protein (fructosamine) concentration in serum consists mainly of glycated albumin and lipoproteins. Measurement of fructosamine is used to diagnose and monitor diabetes mellitus in cats. OBJECTIVE: The aims of this study were to measure glycated proteins in diabetic and healthy (nondiabetic) cats using a semiquantitative technique and to determine whether measurement of any of the fractions of glycated protein could be potentially advantageous for the diagnosis and monitoring of diabetic cats. METHODS: Serum samples from 6 cats with diabetes mellitus and 10 clinically healthy adult cats were assayed for total glycated protein using a nitroblue tetrazolium (NBT) fructosamine assay. Serum proteins were separated by agarose gel electrophoresis and stained with NBT to identify individual glycated proteins within the bands. Gels were scanned by densitometry at 525 nm and the glycated protein content was calculated with reference to the total glycated protein content of the sample. RESULTS: Diabetic cats with increased total fructosamine concentrations had higher concentrations of glycated albumin and glycated alpha- and beta-lipoproteins compared with healthy cats. The concentration of glycated proteins in each of the fractions had a positive linear association with the total glycated protein content of serum, but there was large variation in the relative contributions of the 3 protein fractions to the total glycated protein concentration. CONCLUSIONS: Based on the results of this study, measurement of individual glycated fractions does not seem to offer any potential diagnostic advantage over measurement of total glycated protein (fructosamine) concentration alone. In some diabetic and healthy cats, glycated lipoproteins formed the major part of the total glycated protein, whereas in other cats albumin was the major contributor.     

Anemia in cats with hemotropic mycoplasma infection: Retrospective evaluation of 23 cases (1996–2005)

This study summarizes the diagnostic findings from all anemic cats diagnosed with hemotropic mycoplasma (HM) infections at the Western College of Veterinary Medicine — Veterinary Teaching Hospital between 1996 and 2005. The objectives were to determine the frequency of HM-induced anemia among all cats presented with anemia during this period, the clinical findings and risk factors associated with clinical HM infection, and factors affecting or predicting survival. Medical records were examined from 23 cats with HM-induced anemia from the total of 170 cats diagnosed with anemia during this period. The frequency of HM-induced anemia was 14% (23/170) among all anemic cats. Cats with HM-induced anemia were less likely to be purebred (P = 0.04) than other cats with anemia. Of the cats with HM-induced anemia, those with positive retroviral status (P = 0.01), concurrent illness (P < 0.01), or lack of erythroid regeneration (P = 0.01) were most likely to die. The 1-year survival of HM-infected cats was 65% (13/20).     

Risk factors for time to diagnosis of feline upper respiratory tract disease in UK animal adoption shelters

Feline upper respiratory tract disease (URTD), mainly caused by feline calicivirus (FCV) and feline herpesvirus, is a major cause of disease outbreaks in feline accommodation such as animal shelters, catteries and multi-cat households. We conducted a longitudinal, yearlong study in five UK feline animal shelters to identify risk factors for the time to diagnosis of URTD. We were especially interested in risk factors that could be identified at the time the cat entered the shelter. Shelter staff recorded data for 1434 cats during 2002–2003. Most of the cats were domestic shorthair cats and were from private households, or were stray or abandoned. Sixty cats without clinical signs of URTD at entry had URTD diagnosed (typically within the first month at the centre). We used two multivariable models: one was a Cox proportional-hazards model, and the other a regression analyses with complementary log–log model.The hazard varied substantially between shelters and was considerably lower for the shelter that had a purpose-built admissions unit with its own isolation facilities. The hazard was greater for purebred cats (HR 4.3–5.0) and for neutered cats (HR 2.0). The hazard was also typically greater if the centre had a greater proportion of cats present with URTD. The analyses suggested that the centre-level risk factors were more important in determining hazard than cat-level risk factors.     

Feline diabetes mellitus in the UK: the prevalence within an insured cat population and a questionnaire-based putative risk factor analysis

Prevalence and risk factors for the development of diabetes mellitus (DM) in cats in the United Kingdom have not previously been reported. The prevalence of DM was evaluated in a large insured population and was found to be 1 in 230 cats. In this insured cat population Burmese cats were 3.7 times more likely to develop DM than non-pedigree cats. A convenience-sampling questionnaire-based study was used in order to identify putative risk factors for the development of DM. The univariate risk factor analysis identified being male, neutered, inactive, weighing >or=5 kg and having a history of corticosteroid treatment as significant risk factors for the development of DM in these cats. In addition, male cats treated with megestrol acetate had a significantly increased risk of developing DM compared to females. In contrast, there was no difference in DM occurrence between male and female Burmese cats. A multivariate classification tree-based model on the questionnaire data looking for interactions between risk factors, identified gender as the most important overall risk factor for the development of DM with low physical activity being the next most important risk factor for female cats and breed the next most important for male cats.     

Indirect determination of nitric oxide in cats with cardiomyopathy and arterial thromboembolism

Objective: To determine nitric oxide concentration in cats with hypertrophic or intermediate forms of cardiomyopathy and arterial thromboembolism (ATE) compared to healthy controls and to determine the association between nitric oxide concentration and the presence of ATE, congestive heart failure (CHF), and echocardiographic measurements. Design: Case–control study. Setting: Veterinary teaching hospital. Animals: Client‐owned cats with cardiomyopathy, cardiomyopathy and ATE, and normal cats. Interventions: None. Measurements: All cats underwent 2‐dimensional and M‐mode echocardiography. Nitric oxide was assessed indirectly by measuring the concentration of plasma nitrite+nitrate (NN), end products of nitric oxide metabolism. Plasma arginine concentration and dietary arginine content were also assessed since arginine is a precursor for nitric oxide production. Main results: Twenty‐six cats with cardiomyopathy, 26 cats with cardiomyopathy and ATE, and 29 nor‐mal cats were enrolled. Compared with healthy controls, median NN concentration was significantly higher in cats with cardiomyopathy and cats with both cardiomyopathy and ATE. There was no difference between cats with cardiomyopathy alone and cats with cardiomyopathy and ATE. Nitrate+ nitrite concen‐tration in cats with cardiac disease was unrelated to the presence of CHF, plasma arginine concentration, or dietary arginine content. In cats with cardiac disease, the left atrial diameter, left ven‐tricular diameter in diastole, and age were negatively correlated with NN concentrations. Conclusions: Nitric oxide concentration is elevated in cats with cardiac disease, but the elevation appears to be independent of ATE and CHF.     

Muscle Potassium Content and Potassium Gluconate Supplementation in Normokalemic Cats With Naturally Occurring Chronic Renal Failure

Muscle potassium content and supplementation with potassium gluconate were evaluated in normokalemic cats with chronic renal failure (CRF). Affected cats received standard medical therapy for renal failure and either placebo (sodium gluconate! or potassium gluconate. At the beginning of the study and after 6 months of supplementation, glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were estimated using ³H-inulin and ¹⁴C-tetraethylammo-nium bromide (TEA) clearances. Muscle potassium content was determined in biopsy specimens using atomic absorption spectroscopy. Muscle biopsy samples obtained from cats with CRF before treatment had significantly lower muscle potassium content than did those from normal control cats. Over the 6-month period of supplementation, muscle potassium content increased both in cats with CRF that received potassium gluconate and in those that received placebo (sodium gluconate). Serum potassium concentration and fractional excretion of potassium remained relatively unchanged in both groups of cats throughout the treatment period. There were no significant differences in the percentage change in GFR and ERPF between treatment groups over the 6-month time period. Median values for pH, HCO₃, and total CO₂ at 6 months were higher than baseline in the potassium gluconate group but lower than baseline in the sodium gluconate group.     

Mortality rates and causes of death among emaciated cats

OBJECTIVE: To determine mortality rates and causes of death for thin (i.e., lean or emaciated) cats and, if mortality rates were high, to determine factors associated with risk that cats would be thin. DESIGN: Cohort study. ANIMALS: 1,138 cats examined at 27 private veterinary practices in the northeastern United States. PROCEDURE: Body condition of the cats was scored (emaciated, lean, optimally lean, optimal, heavy, obese) between 1991 and 1992. Follow-up information on whether cats had developed any illnesses, whether cats had died, and, if cats had died, cause of death was obtained between 1994 and 1996. Mortality risk for emaciated cats was estimated, using cats in optimal condition as the reference group. RESULTS: Survival curves for emaciated cats were significantly lower than those for cats of other body conditions. Compared with cats in optimal condition, emaciated cats were 4.4 times as likely to die during the follow-up period. However, after adjusting for age and excluding cats that died within 1 year after body condition was scored, emaciated cats were no longer significantly more likely to die. Emaciated cats were more likely to die of an unknown cause than were cats of optimal condition. Risk factors for emaciated body condition included preexisting illness, age, and Siamese breed. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that emaciated cats had a significantly higher risk of death, compared with cats in optimal body condition. Serious illness and advancing age accounted for much, and perhaps all, of this increased risk of death.     

Association between dietary factors and calcium oxalate and magnesium ammonium phosphate urolithiasis in cats.

OBJECTIVE: To identify dietary factors associated with the increase in occurrence of calcium oxalate (CaOx) uroliths and the decrease in occurrence of magnesium ammonium phosphate (MAP) uroliths in cats. DESIGN: Case-control study. ANIMALS: 173 cats with CaOx uroliths, 290 cats with MAP uroliths, and 827 cats without any urinary tract diseases. PROCEDURE: Univariate and multivariate logistic regression were performed. RESULTS: Cats fed diets low in sodium or potassium or formulated to maximize urine acidity had an increased risk of developing CaOx uroliths but a decreased risk of developing MAP uroliths. Additionally, compared with the lowest contents, diets with the highest moisture or protein contents and with moderate magnesium, phosphorus, or calcium contents were associated with decreased risk of CaOx urolith formation. In contrast, diets with moderate fat or carbohydrate contents were associated with increased risk of CaOx urolith formation. Diets with the highest magnesium, phosphorus, calcium, chloride, or fiber contents and moderate protein content were associated with increased risk of MAP urolith formation. On the other hand, diets with the highest fat content were associated with decreased risk of MAP urolith formation. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that diets formulated to contain higher protein, sodium, potassium, moisture, calcium, phosphorus, and magnesium contents and with decreased urine acidifying potential may minimize formation of CaOx uroliths in cats. Diets formulated to contain higher fat content and lower protein and potassium contents and with increased urine acidifying potential may minimize formation of MAP uroliths.     

A study of feline upper respiratory tract disease with reference to prevalence and risk factors for infection with feline calicivirus and feline herpesvirus.

A cross-sectional survey of a convenience sample of cats was carried out to determine the prevalence of and risk factors for respiratory tract disease, feline calicivirus (FCV) infection and feline herpesvirus (FHV) infection. Seven hundred and forty cats were studied; samples for isolation of FCV and FHV were obtained from 622 (84%). Data on individual cat and household variables were obtained by questionnaire for each cat and analysed using univariable and logistic regression analysis. Thirty-eight percent (282/740) of cats surveyed had respiratory tract disease. Eighteen of 24 predictor variables were found to be significantly (P<0.05) associated with the presence of respiratory tract disease in a cat on univariable analysis. Following logistic regression, several factors retained significance including isolation of FCV and FHV, younger cats (4-11 months of age) and multiple cat households. A negative association was found with breeding catteries and other types of household in comparison with rescue catteries. Overall, feline calicivirus was isolated from 162/622 (26%) of cats sampled; 33% of the cats with respiratory tract disease were FCV positive compared to 21% of healthy cats. Variables significantly associated with FCV isolation on logistic regression were the presence of respiratory tract disease and contact with dogs with and without respiratory tract disease. Feline herpesvirus was isolated from 30/622 (5%) of all cats sampled; 11% of cats with respiratory tract disease were FHV positive compared to 1% of healthy cats. Variables significantly associated with FHV isolation on univariable analysis included age, gender, and the presence of respiratory tract disease. Vaccination showed a negative association. Logistic regression analysis of the data for FHV was limited by the sample size and the low prevalence of FHV.     

Clinical characteristics of mammary carcinoma in male cats

There is little information regarding mammary tumors in male cats. The purpose of this study was to characterize the clinical characteristics of mammary carcinoma in male cats, compare this malignancy to the disease in female cats, and identify prognostic factors. Thirty-nine male cats with mammary carcinoma were identified. One pathologist reviewed the biopsies from all cats, and complete follow-up information regarding outcome was available for 27 cats. Information collected included signalment, age at neutering, history of progestin therapy, age at tumor diagnosis, size of tumor, type of surgery (lumpectomy, simple mastectomy, or radical mastectomy), results of clinical staging, adjunctive therapies, time to local recurrence, survival, and cause of death. The mean age at tumor diagnosis (12.8 years) was slightly older than that reported in female cats. The incidence of local tumor recurrence in 9 of 20 (45%) cats was similar to that reported in females. A history of progestin therapy was present in 8 of 22 (36%) cats for which this information was known. The median time to local recurrence was 310 days (range 127-1,363 days), and overall median survival was 344 days (range 14-2,135 days). Tumor size and lymphatic invasion were identified as negative prognostic factors. This study indicates that mammary carcinoma in the male cat has many similarities to the disease in females, with an aggressive clinical course in most cats.     

Qualitative Risk Assessment of Chronic Renal Failure Development in Healthy,Female Cats as Based on the Content of Eicosapentaenoic Acid in Adipose Tissue and That of Arachidonic Acid in Plasma Cholesteryl Esters

A study was carried out to assess the qualitative risk of development of chronic renal failure (CRF) in young healthy, female cats as based on the content of arachidonic acid (AA) in plasma cholesteryl esters (CE) and eicosapentaenoic acid (EPA) in adipose tissue. It has been suggested that the content of AA in CE should be <10% of total fatty acids (TFA) and of EPA in adipose tissue be >1.4% of TFA. Subcutaneous adipose tissue and blood samples were obtained from 48 female cats. There was a statistically significant correlation between linoleic acid content of adipose tissue and that of plasma CE. In all cats the EPA content of adipose tissue was lower than 1.4% of TFA and in 30 cats that of AA in plasma CE was higher than 10% of TFA. The EPA content of adipose tissue and the AA content of plasma CE are determined by the contents of these fatty acids in the diet. It is concluded that the fatty acid composition of cat foods should be determined and that, if deemed necessary, the ingredient composition should be altered so that the content of EPA is raised and that of AA is lowererd.