Renal clearance studies in cats with chronic renal disease: Dietary implications

Renal clearance studies were undertaken on 15 cats, 10 with mild chronic renal disease (CRD) and five with severe CRD. Plasma creatinine concentration and urinary specific gravity measurements in the mild and severe CRD cats were significantly different (P < 0–05) and were 131 ± 26-7 umol/litre and 1–034 ± 0–016, and 392 ± 117-3 nmol/litre and 1–015 ± 0–002, respectively. Endogenous creatinine clearance in the mild and severe CRD cats were significantly different (P < 0–01) and were 2–3 ± 0–58 and 0–62 ± 0–230 ml/min/kg bodyweight, respectively. Hypokalemia was present in one cat but it was not associated with hypercalcinuria. Two cats with mild CRD had hypophosphataemia, hypercalcaemia and hyperphosphaturia which was suggestive of primary hyperparathyroidism, while two cats with severe CRD had hyperphosphataemia and hyperphosphaturia which was indicative of renal secondary hyperparathyroidism. Eight of the 15 cats were subsequently necropsied and were found to have segmental atrophic nephropathy.     

Evaluation of dietary patterns in dogs with cardiac disease

OBJECTIVE: To determine the dietary patterns and intake of nutrients of concern in dogs with cardiac disease. DESIGN: Prospective study. ANIMALS: 82 dogs with dilated cardiomyopathy (DCM) or chronic valvular disease. PROCEDURE: Owners of dogs were contacted and given a standardized telephone questionnaire regarding diet and a 24-hour food recall to determine daily intake of calories, protein, fat, sodium, potassium, and magnesium. RESULTS: Among the 82 dogs, 71% had no congestive heart failure (CHF), and 29% had CHF or a history of CHF. Sixty-one percent of dogs had concurrent diseases. Anorexia was or had been evident in 34% of dogs and was significantly more common in the CHF group and in dogs with DCM. Most dogs (92%) received some treats and table food, with a median percentage of daily calories from treats of 19% (range, 0% to 100%). Most owners (57%) that administered pills used human or pet foods for pill administration. Most dogs ate more than the Association of American Feed Control Officials (AAFCO) minimum values for fat and protein. Daily sodium intake varied from 14 to 384 mg/100 kcal, compared with the AAFCO minimum of 17 mg/100 kcal. A median of 25% of total daily sodium came from treats and table food (range, 0% to 100%). Dogs with CHF ate significantly more sodium, compared with dogs with no CHF. CONCLUSIONS AND CLINICAL RELEVANCE: Dietary intake for dogs with cardiac disease is highly variable and often not optimal.     

Myocardial taurine concentrations in cats with cardiac disease and in healthy cats fed taurine-modified diets.

Myocardial taurine concentrations were measured in cats with cardiac disease and in healthy cats fed diets with various concentrations of taurine. Group 1 was composed of 26 cats with 3 categories of naturally developing cardiac disease: dilatative cardiomyopathy (group 1A), 10 cats; hypertrophic cardiomyopathy (group 1B), 9 cats; and volume overload (group 1C), 7 cats. These cats had been fed various commercial diets. Group 2 was composed of 40 healthy cats that had been fed diets varying in taurine concentration (0 to 1% taurine) for at least 2 years. Mean myocardial taurine concentrations did not differ significantly between group-1 cats with dilatative cardiomyopathy and those with hypertrophic cardiomyopathy or volume overload. Cats in group 1A had a mean myocardial taurine concentration 3 times higher than healthy cats fed a taurine-free diet (P less than 0.002). Mean myocardial taurine concentrations did not differ significantly between group-1A cats and healthy cats fed a diet containing 0.02% taurine; group-1A cats had significantly lower mean myocardial taurine concentrations than did healthy cats fed a synthetic diet containing 0.05 or 1.0% taurine (P less than 0.001). Acute oral administration of taurine in 5 group-1A cats appeared to increase mean myocardial taurine concentrations, compared with similar cats not given taurine during treatment for cardiac failure. In group-2 cats, mean myocardial taurine concentrations increased directly with percentage of dietary taurine.     

Prevalence of echocardiographic evidence of cardiac disease in apparently healthy cats with murmurs

The objective of this prospective study was to determine the prevalence of echocardiographic evidence of heart disease in apparently healthy cats with heart murmurs. Thirty-two privately owned domestic cats were examined. All cats were considered healthy on the basis of history and physical examination, except for the finding of a heart murmur on auscultation. Cats on any medications (besides regular flea, tick and heartworm preventative) or that were pregnant or lactating were excluded from this study. The prevalence of echocardiographic evidence of heart disease in this population of cats was 53%. Therefore, identification of a heart murmur on routine physical examination in apparently healthy cats warrants further investigation.     

Dietary hypersensitivity in cats and dogs

Adverse reactions to food or dietary hypersensitivity are frequently seen problems in companion animal medicine and may be difficult to differentiate from inflammatory bowel disease (IBD). Dietary hypersensitivity can be divided into two subgroups: immunological and nonimmunological problems. Non-immunological problems can be subdivided into food intolerance, food poisoning, and dietary indiscretion. The immunological group can be subdivided into true food allergy (IgE mediated) and anaphylaxis (non-IgE mediated). This article gives an outline of what dietary hypersensitivity is, and more specifically food allergy and how to deal with patients with possible dietary hypersensitivity.     

Reproductive patterns of pedigree cats

A survey of Brisbane catteries was carried out to investigate reproductive patterns of pedigree cats. Eighteen breeders supplied data on 751 litters with a total of 3171 kittens covering the Persian, Chinchilla, Siamese, Burmese and Abyssinian breeds. The overall sex ratio at birth was 100 males to 92 females. There was a significant seasonal effect on sex ratio with litters conceived during the wet season (September to February) producing more males than expected and litters conceived during the dry season producing more females than expected. Litter size and breed had no significant effect on the sex ratio. The average litter size varied with the breed with the most prolific being the Burmese (5.0) then the Siamese (4.5), Persian (3.9), Abyssinian (3.5) and Chinchilla (2.8). The average litter size was smaller for the first litter than for the subsequent 3 litters. The maximum average litter size was reached at 6 years with only a moderate decline thereafter. There was a seasonal fluctuation in births with the greatest numbers being born in spring and the least in late autumn. Longhair cats showed a more marked seasonal distribution of births than the shorthairs which reproduced for most of the year, particularly the Burmese breed.     

Airway microbial culture and susceptibility patterns in dogs and cats with respiratory disease of varying severity

Objective – To compare airway microbiological culture and susceptibility results in 2 groups of dogs and cats: 1 with respiratory failure requiring positive pressure ventilation (PPV) and 1 with respiratory disease. Design – Retrospective study. Setting – University teaching hospital. Animals – Fifty‐two dogs and cats requiring PPV that had an airway microbiologic culture submitted from October 1, 2003 to October 31, 2008 were included. One hundred and four airway microbiologic cultures from dogs and cats with respiratory disease not requiring PPV were randomly sampled for comparison. Interventions – None. Measurements and Main Results – Patients with respiratory failure were more likely to have a gram‐negative enteric isolate identified (P<0.001), while patients with respiratory disease were more likely to have a gram‐negative nonenteric isolate (P<0.001) or anaerobic isolate (P<0.001) identified. Aerobic bacterial isolates from patients with respiratory failure were less likely to be susceptible to ampicillin (P=0.006), amoxicillin/clavulonate (P<0.001), chloramphenicol (P=0.004), enrofloxacin (P<0.001), ticarcillin/clavulonate (P=0.004), and the combination of ampicillin with enrofloxacin (P<0.001) than were aerobic bacterial isolates from patients with respiratory disease. Conclusions – Canine and feline patients with respiratory failure severe enough to require PPV exhibit a different pattern of bacterial isolates cultured from their airways when compared with isolates from patients with respiratory disease that has not resulted in ventilator dependence. These isolates are more likely to be resistant to commonly used antimicrobials/antimicrobial combinations than patients in the respiratory disease group. These findings suggest that in canine and feline patients with infectious lower respiratory tract disease, consideration of the severity of the pulmonary insult may allow for better prediction of likely isolates and their antimicrobial susceptibilities. Further prospective studies with a standardized collection technique are warranted.     

Evaluation of the renin-angiotensin system in cardiac tissues of cats with pressure-overload cardiac hypertrophy

OBJECTIVE: To clarify regulation of the renin-angiotensin (RA) system in cardiac tissues by measuring angiotensin-converting enzyme (ACE) and chymase activities in cats with pressure-overload cardiac hypertrophy. ANIMALS: 13 adult cats. PROCEDURES: Pressure-overload cardiac hypertrophy was induced by coarctation of the base of the ascending aorta in 6 cats, and 7 cats served as untreated control animals. Cats were examined before and 3 months and 2 years after surgery. Two years after surgery, cardiac hypertrophy was confirmed by echocardiography, and the blood pressure gradient was measured at the site of constriction. Cats were euthanized, and ACE and chymase activities were measured in cardiac tissues. RESULTS: Mean +/- SD pressure gradient across the aortic constriction was 63 +/- 6 mm Hg. Chymase activity predominated (75% to 85%) in the RA system of the cardiac tissues of cats. Fibrosis in the wall of the left ventricle was detected in cats with hypertrophy, and fibrosis of the papillary muscle was particularly evident. CONCLUSIONS AND CLINICAL RELEVANCE: Chronic pressure overload on the heart of cats can activate the RA system in cardiac tissues. A local increase in angiotensin II was one of the factors that sustained myocardial remodeling.     

Radiographic signs in cats with nasal disease

Radiographic signs in 64 cats that had radiography as part of the diagnostic work-up for suspected nasal disease were reviewed in a blinded fashion. Final diagnoses in these cats were rhinitis in 27, primary nasal neoplasia in 21 and non-nasal disease in 16. The signs with highest predictive value for nasal neoplasia were displacement of midline structures (73%), unilateral generalised soft tissue opacity (70%), unilateral generalised loss of turbinate detail (69%) and evidence of bone invasion (64%). The only radiographic finding that occurred more frequently in cats with rhinitis was a nasal cavity within normal limits, and the predictive value of this sign was only 38%. Radiographic signs in cats with nasal neoplasia are similar to those reported in dogs, whereas the radiographic signs in cats with rhinitis are variable and non-specific, and may be absent.     

Markers of Borna disease virus infection in cats with staggering disease

Borna disease virus (BDV) is a RNA-virus causing neurological disorders in a wide range of mammals. In cats, BDV infection may cause staggering disease. Presently, staggering disease is a tentative clinical diagnosis, only confirmed at necropsy. In this study, cats with staggering disease were investigated to study markers of BDV infection aiming for improvement of current diagnostics. Nineteen cats fulfilled the inclusion criteria based on neurological signs and pathological findings. In 17/19 cats, BDV infection markers (BDV-specific antibodies and/or BDV-RNA) were found, and antibodies in serum (13/16, 81%) were the most common marker. BDV-RNA was found in 11/19 cats (58%). In a reference population without neurological signs, 4/25 cats were seropositive (16%). The clinical history and neurological signs in combination with presence of BDV infection markers, where serology and rRT-PCR on blood can be helpful tools, improve the diagnostic accuracy in the living cat.     

Serum gamma-glutamyl transpeptidase activity in healthy cats and cats with induced hepatic disease

Activities of serum gamma-glutamyl transpeptidase (GGT), alkaline phosphatase (ALP), and alanine aminotransferase (ALT) were determined in healthy cats and in cats before and after treatment: common bile duct ligation, carbon tetrachloride administration, sham surgery, or anesthesia only. Significant (P less than 0.01) increases in serum GGT, ALP, and ALT occurred in cats with ligated bile ducts. Significant (P less than 0.01) increases in serum ALT occurred in carbon tetrachloride-treated cats. Increases of serum GGT, ALP, or ALT were not observed in cats subjected to sham surgery or anesthesia only compared with these cats' baseline values and values in healthy cats. Tissue GGT activity was measured in liver, renal cortex, jejunal mucosa, and bile ducts. There was a 1.5-fold increase in GGT activity in livers of cats with ligated bile ducts, compared with that in livers of healthy cats.     

Limited sampling pharmacokinetics of subcutaneous ondansetron in healthy geriatric cats,cats with chronic kidney disease,and cats with liver disease

Ondansetron, a 5‐HT₃ receptor antagonist, is an effective anti‐emetic in cats. The purpose of this study was to compare pharmacokinetics of subcutaneous (SQ) ondansetron in healthy geriatric cats to cats with chronic kidney disease (CKD) or liver disease using a limited sampling strategy. 60 cats participated; 20 per group. Blood was drawn 30 and 120 min following one 2 mg ( mean 0.49 mg/kg , range 0.27–1.05 mg/kg ) SQ dose of ondansetron. Ondansetron concentrations were measured by liquid chromatography coupled to tandem mass spectrometry. Drug exposure represented as area under the curve (AUC) was predicted using a limited sampling approach based on multiple linear regression analysis from previous full sampling studies, and clearance (CL/F) estimated using noncompartmental methods. Kruskal–Wallis anova was used to compare parameters between groups. Mean AUC (ng/mL·h) of subcutaneous ondansetron was 301.4 (geriatric), 415.2 (CKD), and 587.0 (liver). CL/F (L/h/kg) of SQ ondansetron was 1.157 (geriatric), 0.967 (CKD), and 0.795 (liver). AUC was significantly higher in liver and CKD cats when compared to geriatric cats (P < 0.05). CL/F in liver cats was significantly decreased (P < 0.05) compared to geriatric cats. In age‐matched subset analysis, AUC and CL/F in liver cats remained significantly different from geriatric cats.