Association of four differently processed diets with plasma and urine advanced glycation end products and serum soluble receptor for advanced glycation end products concentration in healthy dogs

Advanced glycation end products (AGEs), formed via the Maillard reaction (MR) during processing of foods, have been implicated in inflammatory and degenerative diseases in human beings. Cellular damage is primarily caused by AGE binding with the receptor for AGEs (RAGE) on cell membranes. An isoform of RAGE, soluble RAGE (sRAGE), acts as a decoy receptor binding circulating AGEs preventing cellular activation. Pet food manufacturing involves processing methods similar to human food processing that may increase dietary AGEs (dAGEs). We hypothesized that diet, plasma and urine AGEs, and serum sRAGE concentrations would differ between thermally processed diets. This study examined the association of four differently processed diets: ultra-processed canned wet food (WF); ultra-processed dry food (DF); moderately processed air-dried food (ADF) and minimally processed mildly cooked food (MF) on total plasma levels of the AGEs, carboxymethyllysine (CML), carboxyethyllysine (CEL), methylglyoxal hydroimidazolone-1, glyoxal hydroimidazolone-1, argpyrimidine, urine CML, CEL and lysinoalanine, and serum sRAGE concentration. Ultra-high-performance liquid chromatography-tandem mass spectrometry was used to measure AGEs. sRAGE concentration was measured using a commercial canine-specific enzyme-linked immunosorbent assay kit. Total dAGEs (mg/100 kcal as fed) were higher in WF than in other diets. Plasma total AGEs (nM/50 μL) were significantly higher with WF, with no difference found between DF, ADF, and MF; however, ADF was significantly higher than MF. Urine CML (nmol AGEs/mmol creatinine) was significantly higher with DF than with WF and MF. There were no significant differences in total urine AGEs or serum sRAGE concentration between diets. In conclusion, different methods of processing pet foods are associated with varied quantities of AGEs influencing total plasma AGE concentration in healthy dogs. Serum sRAGE concentration did not vary across diets but differences in total AGE/sRAGE ratio were observed between MF and WF and, ADF and DF.

d,l-Methionine in combination with amoxicillin-clavulanic acid successfully dissolves spontaneously occurring infection-induced struvite urocystoliths in dogs: a pilot study

OBJECTIVE

To determine the efficacy and safety of a urinary acidifier (d,l-methionine [Methio-Form]) and an antimicrobial agent (amoxicillin-clavulanic acid [Clavamox]) without changing diet for dissolving infection-induced struvite urocystoliths in dogs.

ANIMALS

14 dogs were recruited for this prospective study; 11 completed it and 3 dogs withdrew due to inability of the owners to administer the treatment (n = 2) or refusal of treatment by the dog (1).

PROCEDURES

All dogs were administered d,l-methionine (approx initial dose of 75 mg/kg, PO, q 12 h) and amoxicillin-clavulanic acid (22 mg/kg, PO, q 12 h) based on urine culture and sensitivity. Urine pH, urinalysis, urine culture, venous blood gas and serum biochemical analysis, and lateral survey abdominal radiographic images were evaluated initially and every 4 weeks until urolith dissolution (success) or lack of change in size and/or shape of urocystoliths on 2 consecutive reevaluation points (failure) occurred.

RESULTS

Uroliths dissolved in 8 of 11 dogs in a median of 2 months (range, 1 to 4 months) with a final effective dosage of d,l-methionine of approximately 100 mg/kg, PO, every 12 hours. In 3 dogs, uroliths failed to dissolve and were removed surgically; they contained variable amounts of calcium oxalate. No adverse events occurred.

CLINICAL RELEVANCE

Infection-induced struvite urolithiasis is 1 of the 2 most common minerals occurring in canine uroliths. Results of this study supported the use of d,l-methionine and amoxicillin-clavulanic acid without changing diet for dissolution of infection-induced struvite urocystoliths in dogs.

Weight measurements result in improved accuracy and precision in preparation of cooked homemade diets for dogs

OBJECTIVE

Accurate measurement of ingredients for cooked homemade diets helps ensure diets are complete and balanced. Studies have demonstrated measuring dry dog food with measuring cups results in significant inaccuracy. Therefore, measuring ingredients by volume when preparing these diets may be inaccurate. The purpose was to determine the accuracy of preparing cooked homemade diets by measuring ingredients by volume (measuring cups and spoons) or weight (digital gram scale with a syringe for measuring oil only).

SAMPLES

42 diet samples prepared by 21 participants.

PROCEDURES

21 participants were instructed on homemade diet preparation based on weight or volume measurement methods. Diet samples underwent proximate analysis and mineral analysis. Data, expressed on a dry matter basis (DMB) and an energy density basis (EDB), from both groups were compared to the anticipated nutrient profile to determine which method resulted in more accuracy. Data from individual samples within each group were compared to each other to determine the precision of both methods.

RESULTS

Weight measurements were more precise for crude protein, crude fat, nitrogen-free extract, and potassium (DMB and EDB) and more accurate for ash (DMB and EDB) and iron (EDB). Comparatively, volume measurements were more precise for ash (DMB) and more accurate for iron (DMB).

CLINICAL RELEVANCE

Findings suggest weight measurements should be utilized to prepare cooked homemade diets for dogs to promote precision and accuracy.

Management of a urethral tear with porcine small intestinal submucosa-augmented urethroplasty and balloon dilation for subsequent urethral stricture in a cat

CASE DESCRIPTION

As a result of vehicular trauma, a 3-year-old neutered male domestic shorthair cat sustained luxation of the sacrocaudal joint and a urethral tear.

CLINICAL FINDINGS

Retrograde contrast urethrocystography revealed a urethral tear at the level of the ischiatic tuberosity. Conservative treatment for 7 days with a urethral catheter was unsuccessful.

TREATMENT AND OUTCOME

An approach for a perineal urethrostomy was performed and revealed a large urethral tear (4 mm in length in a craniocaudal orientation and encompassing approx 50% of the urethral circumference) proximal to the bulbourethral glands. Urethroplasty was performed with a graft of a rectangular section of single-layer porcine small intestinal submucosa. Perineal urethrostomy was then completed routinely, and a urethral catheter was left in place for 5 days. Two days after removal of the urethral catheter, stranguria was noted. Retrograde contrast urethrocystography revealed a urethral stricture. Balloon dilation of the urethral stricture was performed, and the cat's stranguria improved. Ten weeks following balloon dilation, the cat developed hematuria, and a urinary tract infection and urethral stricture were diagnosed. Balloon dilation was repeated with instillation of triamcinolone solution at the stricture site. Eighteen months later (approx 21 months after the initial surgery), the cat was urinating normally.

CLINICAL RELEVANCE

The outcome for the cat of this report indicated that porcine small intestinal submucosa may be used to successfully augment urethroplasty for treatment of traumatic urethral tears in cats. Urethral balloon dilation with triamcinolone instillation may be used to treat postoperative urethral strictures.

Lateral rhinotomy and coblation for treatment of a nasal hamartoma in a dog

CASE DESCRIPTION

A 4-year-old spayed female French Bulldog was referred for treatment of a suspected right-sided nasal angiofibroma associated with a 4-month history of unilateral nasal discharge and stertor.

CLINICAL FINDINGS

The dog appeared healthy other than right-sided mucoid debris and decreased airflow through the right naris. The dog was anesthetized, and a large intranasal mass was observed obstructing the right nasal passage and abutting the nasal septum.

TREATMENT AND OUTCOME

A lateral rhinotomy was performed, and rigid endoscopes (0° and 30°) were used to examine the right nasal cavity. The mass filled the anterior aspect of the nasal cavity and involved a portion of the nasal turbinates with some erosion. A coblation unit was used to ablate tumor tissue laterally to remove the tumor in piecemeal fashion. Recovery was routine with only minor epistaxis after surgery, and the dog was discharged the next day. Eight months after surgery, follow-up CT revealed right-sided nasal turbinate and conchal atrophy consistent with prior mass ablation. No macroscopic recurrence was detected, and the owners reported only rare, clear rhinorrhea.

CLINICAL RELEVANCE

Findings suggested that coblation may be an alternative to radiation therapy for vascular tumors with minimal invasion and low metastatic potential.

Effect of a Leucine/Pyridoxine Nutraceutical on Caloric Intake and Body Composition of Obese Dogs Losing Weight

The aim of this 29-week randomized, positively and negatively controlled study was to investigate whether a nutraceutical containing 1 g leucine and 13 mg pyridoxine can enhance weight loss while maintaining lean muscle mass in obese dogs. Twenty-four healthy, 2-year-old beagles were initially divided into obesification (n = 18) or ideal body weight groups (n = 6). After obesification, the 18 dogs were divided into three weight loss groups and fed one of the following over 12 weeks: nutraceutical with canned adult diet (CAD; ObN), placebo with CAD (ObP), or a canned therapeutic weight loss diet (WLD). Dogs in the ideal body weight (IBW) group were fed maintenance calorie requirements with CAD over 12 weeks. Based on MANOVA, ObN and WLD lost similar amounts of total weight (3.6 ± 0.9 vs. 4.4 ± 1.1 kg, respectively) and fat mass (3.1 ± 0.6 vs. 3.9 ± 0.8 kg, respectively) after 12 weeks of treatment, and more than ObP (1.1 ± 1.2 kg weight; 0.9 ± 1.0 kg fat; p < 0.0001). These data show the nutraceutical is a promising option for successful weight loss in dogs. Maintenance levels of CAD were able to induce weight loss without risk of hypo- or anorexia, or the need to switch diets or restrict energy intake.

Pyloric outflow obstruction secondary to sclerosing encapsulating peritonitis in a dog

A 6-year-old, male neutered mixed breed dog was presented emergently with a three-week history of hyporexia, vomiting, diarrhoea and weight loss. Upon examination, the patient was dull, had generalised muscle atrophy, moderate abdominal pain and a mild amount of peritoneal effusion. A fluid-filled, distended, corrugated small bowel with marked gastroparesis and moderate peritoneal effusion was noted on abdominal ultrasonography. Endoscopy revealed hyperaemic and friable mucosa and a subjectively narrowed pylorus. Emergency exploratory celiotomy was performed due to worsening patient condition and revealed thick, diffuse, fibrous adhesions of the abdominal cavity. Based on these findings, sclerosing encapsulating peritonitis (SEP) was suspected. A large mass of omentum adjacent to the greater curvature of the stomach had caused a pyloric outflow obstruction. Adhesiolysis was attempted but was unsuccessful due to the friability of the small intestines. The dog was humanely euthanased under anaesthesia. A diagnosis of SEP was confirmed via necropsy. No underlying cause was identified. This is the first known case of a pyloric outflow obstruction secondary to SEP in a dog. Although rare, this condition should be considered as a differential for dogs with signs of a pyloric outflow obstruction with concurrent ascites and abdominal pain, hyporexia, vomiting and diarrhoea.

Evaluation of three herbal compounds used for the management of lower urinary tract disease in healthy cats: a pilot study

OBJECTIVES

Lower urinary tract disease (LUTD) occurs commonly in cats, and idiopathic cystitis (FIC) and urolithiasis account for >80% of cases in cats <10 years of age. Although several strategies have been recommended, a common recommendation is to induce dilute urine resulting in more frequent urination and to dilute calculogenic constituents. In addition to conventional therapy using modified diets, traditional Chinese and Western herbs have been recommended, although only one - choreito - has published data available. We evaluated three commonly used herbal treatments recommended for use in cats with LUTD: San Ren Tang, Wei Ling Tang and Alisma. We hypothesized that these three Chinese herbal preparations would induce increased urine volume, decreased urine saturation for calcium oxalate and struvite, and differences in mineral and electrolyte excretions in healthy cats.

METHODS

Six healthy spayed female adult cats were evaluated in a placebo-controlled, randomized, crossover design study. Cats were randomized to one of four treatments, including placebo, San Ren Tang, Wei Ling Tang or Alisma. Treatment was for 2 weeks each with a 1 week washout period between treatments. At the end of each treatment period, a 24 h urine sample was collected using modified litter boxes.

RESULTS

Body weights were not different between treatments. No differences were found in 24 h urinary analyte excretions, urine volume, urine pH or urinary saturation for calcium oxalate or struvite between treatments.

CONCLUSIONS AND RELEVANCE

The results of this study do not support the hypothesis; however, evaluation of longer-term and different dosage studies in cats with LUTD is warranted.

Quantified water intake in laboratory cats from still, free-falling and circulating water bowls, and its effects on selected urinary parameters

OBJECTIVES

The study objectives were to determine if the method of water presentation (still [S], circulating [C] or free-falling [FF] bowl systems) influences daily water consumption in cats in a controlled environment, and whether differences in water intake affect urine relative super saturation (RSS) for calcium oxalate and struvite, urine specific gravity (USG), urine osmolality (Uosmol) and urine volume.

METHODS

Sixteen healthy laboratory cats fed a dry diet were individually housed with urine collection systems. Each cat underwent a randomized 2 week crossover period with all bowl systems, allowing a 1 week acclimation period between each crossover. Water intake was measured daily by bowl weight, accounting for spillage and evaporation. USG and urine volume were measured daily, whereas other urinary parameters were measured at various time points throughout each 14 day crossover period.

RESULTS

Fourteen cats completed the study. Average daily water intake (ml/kg/day), urine volume, USG and urine RSS for struvite and calcium oxalate were not significantly different between water bowls. Uosmol was significantly higher in C compared with S and FF bowl systems (P = 0.009 for both). Three individual cats demonstrated a significant water bowl preference (Cat 4: C >S, P = 0.039; Cat 10: FF >C, P = 0.005; Cat 11: S >C, P = 0.037).

CONCLUSIONS AND RELEVANCE

Overall, water bowl type had no appreciable effect on water intake. Uosmol was the only urinary parameter found to be significantly different, and was higher for the C bowl. The implication of this is unknown, considering water intake did not differ significantly between bowls. Alternative methods to increase water intake should be implemented beyond providing unique water bowls in patients where augmented water intake would be beneficial for disease management.

Feline Calcium Oxalate Urolithiasis: Risk factors and rational treatment approaches

PRACTICAL RELEVANCE

Uroliths occur commonly in the bladder and/or urethra of cats and can be lifethreatening if urethral obstruction occurs. Calcium oxalate accounts for 40-50% of urocystoliths and these stones are not amenable to medical dissolution; therefore, removal by surgery or minimally invasive techniques is required if uroliths must be treated. Medical protocols for prevention involve decreasing urine saturation for minerals that form uroliths.

ETIOPATHOGENESIS

Formation of uroliths is not a disease, but rather a complication of several disorders. Some disorders can be identified and corrected (such as infection-induced struvite urolith formation); others can be identified but not corrected (such as idiopathic hypercalcemia). In most cats with calcium oxalate urolith formation the underlying etiopathogenesis is not known. A common denominator of all these disorders is that they can from time to time create oversaturation of urine with one or more crystal precursors, resulting in formation of crystals.

BASIC CONCEPTS

In order to develop rational and effective approaches to treatment, abnormalities that promote urolith formation must be identified, with the goal of eliminating or modifying them. It is important, therefore, to understand several basic concepts associated with urolithiasis and the factors that promote urolith formation that may be modified with medical treatment; for example, the state of urinary saturation, modifiers of crystal formation, potential for multiple crystal types, and presence of bacterial infection or urinary obstruction.

ACVIM Small Animal Consensus Recommendations on the Treatment and Prevention of Uroliths in Dogs and Cats

In an age of advancing endoscopic and lithotripsy technologies, the management of urolithiasis poses a unique opportunity to advance compassionate veterinary care, not only for patients with urolithiasis but for those with other urinary diseases as well. The following are consensus-derived, research and experience-supported, patient-centered recommendations for the treatment and prevention of uroliths in dogs and cats utilizing contemporary strategies. Ultimately, we hope that these recommendations will serve as a foundation for ongoing and future clinical research and inspiration for innovative problem solving.

Apparent nutrient digestibility of two raw diets in domestic kittens

Objectives

The aim of the study was to evaluate overall dry matter, organic matter, crude protein, crude fat and gross energy digestibility of a feline commercial raw diet and a homemade raw diet compared with a canned, heat-processed diet.

Methods

Six domestic shorthair kittens (20–28 weeks old) were fed three different diets in a Latin square crossover design. Diet A was a commercially available, canned, heat-processed diet. Diet B was a complete commercial, prefrozen, raw diet (commercial raw), and diet C was a raw diet supplement mixed with ground raw meat obtained locally (homemade raw). Both diets A and B were formulated to meet nutritional profile levels for cats at all life stages. Kittens were given specific diet amounts to maintain a 2–4% weight increase per week. Food was measured before and after feedings to determine the amount eaten, and all feces were collected, weighed and frozen prior to submission. Composite food samples and all feces were submitted to a national laboratory for proximate analysis of crude protein, crude fiber, ash, crude fat, moisture and caloric density.

Results

Significantly higher digestibility of dry matter ( P <0.001), organic matter ( P <0.001), crude protein ( P <0.001) and gross energy ( P <0.001) was seen in the raw diets compared with the heat-processed diets. This difference resulted in significantly less fecal matter ( P <0.001) despite similar levels of intake and kcal ingested, and evidence of no difference in fecal scores.

Conclusions and relevance

Higher dry matter, organic matter and protein digestibility was seen in two commercial raw diets compared with a heat-processed diet. Digestibility differences could have been due to variance in dietary protein, fat and carbohydrate concentrations between the diets, variance in dietary ingredients or quality, alterations in protein structure secondary to heat processing, as well as alterations in gastrointestinal flora. Future research examining digestibility in diets with the same macronutrient proportions and ingredients, and mechanisms for any differences, is warranted.

Prevalence of asymptomatic urinary tract infections in morbidly obese dogs

Background. Obesity has reached epidemic proportions in dogs and, as in humans, cost of care has increased due to associated comorbidities. In humans, asymptomatic urinary tract infections (UTI) may be more prevalent in the obese. Asymptomatic bacteriuria (AB) is the term used when UTI are asymptomatic. We hypothesized that morbidly obese dogs are similarly more likely to have asymptomatic bacteriuria than lean, overweight, and moderately obese dogs.

Methods. A retrospective study was undertaken to explore a possible association between obesity and asymptomatic bacteriuria. Records from lean, overweight, and obese dogs receiving both a dual energy absorptiometry (DXA) scan and urine culture were included.

Results. Six positive urine cultures were identified among 46 dogs fulfilling search criteria. All six positive cultures were found in dogs with body fat percentage of >45%. In dogs with body fat percentage of <45%, there were no positive urine cultures.

Discussion. There was an increased prevalence of asymptomatic bacteriuria in the morbidly obese dogs in this study compared to those that were lean, overweight, or moderately obese. Whether antibiotic therapy is necessary in such cases is still being debated, but because asymptomatic bacteriuria may be associated with ascending infections, uroliths, or other complications, the data reported herein support the screening of obese patients for bacteriuria.

Urinalysis

Performing a urinalysis should be part of a minimum database in addition to physical examination, historical information gathering, complete blood cell counts, and serum/plasma biochemical analysis. Urinalysis provides information on function of various organs and information on renal function. It is necessary to interpret blood urea nitrogen and serum/plasma creatinine concentrations and is useful in assessing urine concentrating and diluting ability, glomerular barrier function, tubular function, proteinuria, discolored urine, urolithiasis, and neoplasia. Performing a urinalysis is technically easy and does not require expensive equipment or disposable supplies.

Evaluation of two raw diets vs a commercial cooked diet on feline growth

Objectives The objective of this study was to determine if two raw feline diets were nutritionally adequate for kittens. Methods Twenty-four 9-week-old kittens underwent an Association of American Feed Control Officials' (AAFCO) 10 week growth feeding trial with two raw diet groups and one cooked diet group (eight kittens in each). Morphometric measurements (weight, height and length), complete blood counts, serum chemistry, whole blood taurine and fecal cultures were evaluated. Results Overall, the growth parameters were similar for all diet groups, indicating the two raw diets used in this study supported feline growth, within the limitations of an AAFCO growth feeding trial. Kittens fed the raw diets had lower albumin ( P = 0.010) and higher globulin ( P = 0.04) levels than the kittens fed the cooked diet. These lower albumin levels were not clinically significant, as all groups were still within normal age reference intervals. A red cell microcytosis ( P = 0.001) was noted in the combination raw diet group. Increases in fecal Clostridium perfringens were noted in all groups, along with positive fecal Salmonella serovar Heidelberg and Clostridium difficile toxin in the combination raw diet group. Conclusions and relevance The majority of the parameters for feline growth were similar among all groups, indicating the two raw diets studied passed an AAFCO growth trial. In theory, it is possible to pass an AAFCO growth trial but still have nutrient deficiencies in the long term due to liver and fat storage depots. Some of the raw feeders had elevated globulin and microcytosis, likely associated with known enteropathogenic exposure. Disease risks to both pets and owners are obvious. Additional research in this area is needed to investigate the impact of raw diets on the health of domestic cats.

Relationship of adiponectin and its multimers to metabolic indices in cats during weight change

Adiponectin is an important anti-inflammatory hormone secreted from adipose tissue. The high-molecular-weight form of adiponectin (HMW) closely correlates with insulin sensitivity in human beings. This study uses a novel method of size-exclusion gel chromatography combined with enzyme-linked immunosorbent assay to measure HMW feline adiponectin and determine its relationship to leptin, cholesterol, and insulin sensitivity as cats gain and lose weight. In addition, total adiponectin and its messenger RNA expression in subcutaneous adipose tissue were measured. No correlations were found between total serum adiponectin and subcutaneous adipose messenger RNA expression, fat mass, or measures of insulin sensitivity. This study demonstrates that cats have high percentages of HMW adiponectin. Although weak correlations between HMW adiponectin and fat mass were detected, additional cats are needed to determine if the correlations are significant.

Diagnostic accuracy of a point-of-care urine bacteriologic culture test in dogs

OBJECTIVE

To determine diagnostic accuracy of a compartmented bacteriologic culture and antimicrobial susceptibility testing plate (CCSP) for detection of bacterial urinary tract infection (UTI) in dogs and antimicrobial susceptibility testing of bacterial isolates.

DESIGN

Evaluation study.

SAMPLE

62 frozen, previously characterized bacterial isolates from canine urine cultures and 147 canine urine samples.

PROCEDURES

The study was conducted in 2 phases: preliminary assay validation (phase 1) and diagnostic validation (phase 2). For phase 1, the frozen bacterial isolates were revitalized and tested with the CCSP and with standard aerobic microbiological culture (SAMC). For phase 2, the urine samples were tested with the CCSP and SAMC in parallel.

RESULTS

For phase 1, after 24 hours of culture, 46 of 62 (74%) bacterial isolates had growth on the CCSP and all (100%) had growth in SAMC. For bacterial isolates with growth, the CCSP allowed correct identification of 45 of 46 (98%) isolates. Isolates yielding no growth on the CCSP were gram-positive cocci (Staphylococcus spp [n = 7] and Enterococcus spp [9]). In phase 2, the overall diagnostic accuracy of the CCSP, compared with SAMC, was 94% (sensitivity, 81%; specificity, 99%). The positive predictive value was 98% and negative predictive value was 92%. Susceptibility results for enrofloxacin and trimethoprim-sulfamethoxazole as determined with the CCSP had greatest concordance with those determined by SAMC (71% and 96%, respectively), compared with other antimicrobial susceptibilities.

CONCLUSIONS AND CLINICAL RELEVANCE

Use of the CCSP led to accurate exclusion of UTI in dogs without a UTI but was less reliable for diagnosis of UTI, particularly infections caused by gram-positive cocci. Standard aerobic microbiological culture remains the gold standard for detection of UTI in dogs.

Influence of acidifying or alkalinizing diets on bone mineral density and urine relative supersaturation with calcium oxalate and struvite in healthy cats

OBJECTIVE

To evaluate the influence of acidifying or alkalinizing diets on bone mineral density and urine relative supersaturation (URSS) with calcium oxalate and struvite in healthy cats.

ANIMALS

6 castrated male and 6 spayed female cats.

PROCEDURES

3 groups of 4 cats each were fed diets for 12 months that differed only in acidifying or alkalinizing properties (alkalinizing, neutral, and acidifying). Body composition was estimated by use of dual energy x-ray absorptiometry, and 48-hour urine samples were collected for URSS determination.

RESULTS

Urine pH differed significantly among diet groups, with the lowest urine pH values in the acidifying diet group and the highest values in the alkalinizing diet group. Differences were not observed in other variables except urinary ammonia excretion, which was significantly higher in the neutral diet group. Calcium oxalate URSS was highest in the acidifying diet group and lowest in the alkalinizing diet group; struvite URSS was not different among groups. Diet was not significantly associated with bone mineral content or density.

CONCLUSIONS AND CLINICAL RELEVANCE

Urinary undersaturation with calcium oxalate was achieved by inducing alkaluria. Feeding an alkalinizing diet was not associated with URSS with struvite. Bone mineral density and calcium content were not adversely affected by diet; therefore, release of calcium from bone caused by feeding an acidifying diet may not occur in healthy cats.

Molecular imaging of cyclooxygenase-2 in canine transitional cell carcinomas in vitro and in vivo

The enzyme COX-2 is induced at high levels in tumors but not in surrounding normal tissues, which makes it an attractive target for molecular imaging of cancer. We evaluated the ability of novel optical imaging agent, fluorocoxib A to detect urinary bladder canine transitional cell carcinomas (K9TCC). Here, we show that fluorocoxib A uptake overlapped with COX-2 expression in primary K9TCC cells in vitro. Using subcutaneously implanted primary K9TCC in athymic mice, we show specific uptake of fluorocoxib A by COX-2-expressing K9TCC xenograft tumors in vivo. Fluorocoxib A uptake by COX-2-expressing xenograft tumors was blocked by 70% (P < 0.005) when pretreated with the COX-2 selective inhibitor, celecoxib (10 mg/kg), 4 hours before intravenous administration of fluorocoxib A (1 mg/kg). Fluorocoxib A was taken up by COX-2-expressing tumors but not by COX-2-negative human UMUC-3 xenograft tumors. UMUC-3 xenograft tumors with no expression of COX-2 showed no uptake of fluorocoxib A. In addition, fluorocoxib A uptake was evaluated in five dogs diagnosed with TCC. Fluorocoxib A specifically detected COX-2-expressing K9TCC during cystoscopy in vivo but was not detected in normal urothelium. Taken together, our findings show that fluorocoxib A selectively bound to COX-2-expressing primary K9TCC cells in vitro, COX-2-expressing K9TCC xenografts tumors in nude mice, and heterogeneous canine TCC during cystoscopy in vivo. Spontaneous cancers in companion animals offer a unique translational model for evaluation of novel imaging and therapeutic agents using primary cancer cells in vitro and in heterogeneous cancers in vivo.

Single-dose safety and pharmacokinetic evaluation of fluorocoxib A: pilot study of novel cyclooxygenase-2-targeted optical imaging agent in a canine model

We evaluated preclinical single-dose safety, pharmacokinetic properties, and specific uptake of the new optical imaging agent fluorocoxib A in dogs. Fluorocoxib A, N-[(5-carboxy-X-rhodaminyl)but-4-yl]-2-[1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indol-3-yl]acetamide, selectively binds and inhibits the cyclooxygenase-2 (COX-2) enzyme, which is overexpressed in many cancers. Safety pilot studies were performed in research dogs following intravenous (i.v.) administration of 0.1 and 1  mg/kg fluorocoxib A. Blood and urine samples collected three days after administration of each dose of fluorocoxib A revealed no evidence of toxicity, and no clinically relevant adverse events were noted on physical examination of exposed dogs over that time period. Pharmacokinetic parameters were assessed in additional research dogs from plasma collected at several time points after i.v. administration of fluorocoxib A using high-performance liquid chromatography analysis. The pharmacokinetic studies using 1  mg/kg showed a peak of fluorocoxib A (92±28  ng/ml) in plasma collected at 0.5 h. Tumor specific uptake of fluorocoxib A was demonstrated using a dog diagnosed with colorectal cancer expressing COX-2. Our data support the safe single-dose administration and in vivo efficacy of fluorocoxib A, suggesting a high potential for successful translation to clinical use as an imaging agent for improved tumor detection in humans.

Chronic kidney disease in dogs and cats

Chronic kidney disease (CKD) occurs commonly in older dogs and cats. Advances in diagnostics, staging, and treatment are associated with increased quality and quantity of life. Dietary modification has been shown to increase survival and quality of life and involves more than protein restriction as diets modified for use with CKD are lower in phosphorous and sodium, potassium and B-vitamin replete, and alkalinizing, and they contain n3-fatty acids. Additionally, recognition and management of CKD-associated diseases such as systemic arterial hypertension, proteinuria, and anemia benefit patients. This article summarizes staging and management of CKD in dogs and cats.

Radiotherapy-induced myelosuppression in dogs: 103 cases (2002-2006)

Definitive radiotherapy refers to delivery of large doses, typically 48-62 Gray, of ionizing radiation over several weeks using a daily or alternate-day fractionation schedule. The impact of definitive radiotherapy alone on haematopoiesis in tumour-bearing dogs is unknown. Medical records from 103 dogs receiving definitive (60) Cobalt teletherapy for cancer over a 5-year period were reviewed for signalment, tumour type and location, total radiotherapy dose and fractionation scheme. Complete blood count data were collected before, halfway through, and at the end of radiation treatment, and analysed for changes associated with patient variables. The results demonstrate significant reductions in haematocrit, total white blood cell count, neutrophils, eosinophils, monocytes, lymphocytes and platelets occurred during definitive radiotherapy but remained within laboratory reference intervals. These data are important for anticipation of toxicity associated with combinations of radiotherapy and chemotherapy in dogs but do not support the routine monitoring of haematology parameters during definitive radiotherapy.

Comparison of clonal relatedness and antimicrobial susceptibility of fecal Escherichia coli from healthy dogs and their owners

OBJECTIVE

To determine prevalence of within-household sharing of fecal Escherichia coli between dogs and their owners on the basis of pulsed-field gel electrophoresis (PFGE), compare antimicrobial susceptibility between isolates from dogs and their owners, and evaluate epidemiologic features of cross-species sharing by use of a questionnaire.

SAMPLE POPULATION

61 healthy dog-owner pairs and 30 healthy control humans.

PROCEDURES

3 fecal E coli colonies were isolated from each participant; PFGE profiles were used to establish relatedness among bacterial isolates. Susceptibility to 17 antimicrobials was determined via disk diffusion. A questionnaire was used to evaluate signalment, previous antimicrobial therapy, hygiene, and relationship with dog.

RESULTS

A wide array of PFGE profiles was observed in E coli isolates from all participants. Within-household sharing occurred with 9.8% prevalence, and across-household sharing occurred with 0.3% prevalence. No behaviors were associated with increased clonal sharing between dog and owner. No differences were found in susceptibility results between dog-owner pairs. Control isolates were more likely than canine isolates to be resistant to ampicillin and trimethoprim-sulfamethoxazole. Owners and control humans carried more multdrug-resistant E coli than did dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

Within-household sharing of E coli was detected more commonly than across-household sharing, but both direct contact and environmental reservoirs may be routes of cross-species sharing of bacteria and genes for resistance. Cross-species bacterial sharing is a potential public health concern, and good hygiene is recommended.

Prevalence of urovirulence genes cnf, hlyD, sfa/foc, and papGIII in fecal Escherichia coli from healthy dogs and their owners

OBJECTIVE

To determine the prevalence of 4 urovirulence genes in fecal Escherichia coli isolates from healthy dogs and their owners and to determine whether detection of E coli strains with these genes was associated with a history of urinary tract infection (UTI).

SAMPLE POPULATION

61 healthy dog-owner pairs and 30 healthy non-dog owners.

PROCEDURES

A fecal specimen was obtained from each participant, and 3 colonies of E coli were isolated from each specimen. A multiplex PCR assay was used to detect 4 genes encoding virulence factors: cytotoxic necrotizing factor (cnf), hemolysin (hlyD), s-fimbrial and F1C fimbriae adhesin (sfa/foc), and pilus associated with pyelonephritis G allele III (papGIII). Human participants completed a questionnaire to provide general information and any history of UTI for themselves and, when applicable, their dog.

RESULTS

26% (16/61) of dogs, 18% (11/61) of owners, and 20% (6/30) of non-dog owners had positive test results for >or= 1 E coli virulence gene. One or more genes were identified in fecal E coli isolates of both dog and owner in 2% (1/61) of households. There was no difference in the detection of any virulence factor between dog-owner pairs. Female owner history of UTI was associated with detection of each virulence factor in E coli strains isolated from their dogs' feces.

CONCLUSIONS AND CLINICAL RELEVANCE

Dogs and humans harbored fecal E coli strains possessing the genes cnf, hlyD, sfa/foc, and papGIII that encode urovirulence factors. It was rare for both dog and owner to have fecal E coli strains with these virulence genes.

Evaluation of peripheral blood neutrophil function in tumor-bearing dogs

BACKGROUND

Peripheral blood neutrophils of untreated human cancer patients have been shown to have normal, increased, and decreased phagocytic activity, killing capacity, and/or oxidative burst activities.

OBJECTIVES

The objectives of this study were to evaluate oxidative burst and phagocytic activities of peripheral blood neutrophils from tumor-bearing dogs before therapy and compare them with neutrophil function of healthy control dogs.

METHODS

Heparinized whole blood was obtained from dogs with high-grade lymphoma (n=23), sarcoma (n=13), or carcinoma (n=11), and healthy control dogs (n=11) for flow cytometric evaluation of oxidative burst and phagocytic activities. Percentage of bursting cells and amount of oxidative burst activity were determined after stimulation with phorbol 12-myristate 13-acetate (PMA) or Escherichia coli. Percentage of phagocytic cells and amount of phagocytic activity were determined after incubation with fluorescent E. coli.

RESULTS

Compared with control dogs, dogs with sarcoma (P=.004) and carcinoma (P=.05) had a lower percentage of neutrophils exhibiting oxidative burst activity after stimulation with PMA. Phagocytic activity was significantly lower in dogs with sarcomas compared with control dogs (P<.0001) and dogs with lymphoma (P=.01).

CONCLUSIONS

Untreated carcinomas and sarcomas in dogs may suppress the percentage of neutrophils capable of oxidative burst when stimulated by PMA. Furthermore, sarcomas also may suppress the amount of phagocytic activity per neutrophil. Until further studies can be performed, the clinical significance of these findings is unknown.

Effect of Polyprenyl Immunostimulant on the survival times of three cats with the dry form of feline infectious peritonitis

Feline infectious peritonitis (FIP) is considered a fatal disease. Three cats with dry form FIP were treated with Polyprenyl Immunostimulant. Two of the three cats are still on treatment and are alive and well 2 years after diagnosis. The third cat survived 14 months but was treated for only 4.5 months. Further studies are necessary to assess the potential of the Polyprenyl Immunostimulant.

Effects of L-asparaginase on plasma amino acid profiles and tumor burden in cats with lymphoma

BACKGROUND

L-Asparaginase (Elspar(a)), is an Escherichia coli-derived enzyme that depletes lymphoma cells of asparagine, inhibiting protein synthesis and resulting in cell death. The single agent response rate in cats with lymphoma and impact of L-asparaginase on plasma amino acid concentrations is unknown.

HYPOTHESES

L-Asparaginase significantly reduces plasma asparagine concentrations and has demonstrable efficacy against untreated lymphoma in cats.

ANIMALS

Thirteen cats with confirmed lymphoma (LSA) of any anatomic site were given 1 dose 400 IU/kg IM) of L-asparaginase for initial LSA treatment.

METHODS

Plasma collected at 0, 2, and 7 days after L-asparaginase therapy was assayed for ammonia, asparagine, aspartic acid, glutamine, and glutamic acid concentrations. Cats were restaged 7 days later to assess tumor response.

RESULTS

Eight cats had T-cell LSA, 4 cats had B-cell LSA, and 1 cat's immunophenotype was unknown. Two complete and 2 partial responses to L-asparaginase were seen. Four cats had stable disease, and 5 cats had progressive disease. Ammonia and aspartic acid concentrations were increased from baseline at 2 and 7 days posttreatment. Asparagine concentrations were decreased from baseline at 2 days but not 7 days posttreatment. Glutamic acid concentrations were increased at day 2 compared to day 7 posttreatment but not compared to baseline. Glutamine concentrations were unchanged.

CONCLUSIONS AND CLINICAL IMPORTANCE

L-asparaginase significantly reduced asparagine concentrations within 2 days of treatment, but this effect was lost within 7 days. The apparent overall response rate of feline LSA to L-asparaginase in this study was 30%.

Comparison of various methods for estimating body fat in dogs

Obesity is considered one of the most common forms of malnutrition occurring in dogs. Laboratory methods of evaluation of body composition in live dogs have included dual-energy X-ray absorptiometry (DEXA) and deuterium oxide (D(2)O) dilution. Clinical methods of evaluation include assigning a body condition score (BCS) based on visual observation, palpation, and morphometric measurements. This study used these four methods to evaluate 23 healthy, adult, client-owned dogs. Good correlation (coefficient of determination [r(2)]=0.78) was found between measurements of percent body fat (%BF) determined by the D(2)O dilution method and the DEXA scan. Percent body fat can also be estimated using BCS (r(2)=0.92 comparison with DEXA) or by using morphometric measurements with simple calculations (r(2)=0.92 comparison with DEXA).

Nutrition and lower urinary tract disease in cats

Lower urinary tract disease occurs commonly in cats and is often associated with crystal-related disease. Dietary modification is beneficial in managing some of these diseases, including idiopathic cystitis, urolithiasis, and urethral matrix-crystalline plugs. Altering dietary formulation may result in decreasing urinary concentrations of crystallogenic compounds, increasing urinary concentrations fo crystallogenic inhibitors, and diluting urine composition.

Influence of prednisolone on urinary calcium oxalate and struvite relative supersaturation in healthy young adult female domestic shorthaired cats

Prednisolone (10 mg PO q24h) or placebo was administered to healthy cats for 2 weeks in a masked, placebo-controlled, crossover-design study, and 24-hour urine samples were collected. When cats received prednisolone, 24-hour urine pH was lower and 24-hour urine excretion of creatinine, magnesium, phosphate, and potassium was higher than when cats received placebo. No significant difference was found in urinary relative supersaturation for calcium oxalate (CaOx) or struvite between treatment groups. Prednisolone administration did not induce diuresis, nor was it associated with increased calcium excretion or urinary saturation for CaOx in these healthy cats. Results of this study, however, should not be extrapolated to cats that form CaOx uroliths associated with idiopathic hypercalcemia.

Influence of hydrochlorothiazide on urinary calcium oxalate relative supersaturation in healthy young adult female domestic shorthaired cats

Hydrochlorothiazide (1 mg/kg PO q12h) or placebo was administered to healthy cats for 2 weeks in a masked, placebo-controlled, crossover-design study, and 24-hour urine samples were collected. When cats received hydrochlorothiazide, 24-hour urine volume, ammonia, chloride, creatinine, magnesium, oxalic acid, phosphate, potassium, and sodium were significantly higher than when cats received placebo. Hydrochlorothiazide was associated with significantly lower urinary saturation for calcium oxalate, but no difference was found in 24-hour urine calcium and citrate, urinary saturation for struvite, or blood ionized calcium. Hydrochlorothiazide decreased urinary saturation for calcium oxalate and could be useful in managing cats with calcium oxalate uroliths. Results of this study, however, should not be extrapolated to cats that form calcium oxalate uroliths.

Nutrition and Osteoarthritis in Dogs: Does It Help?

Osteoarthritis (OA) is a common disease, and nutrition has become an integral part of management. This article focuses on the role and dietary ingredients in OA, evaluating current evidence for obesity management, omega-3 fatty acids, and chondromodulating agents. Additionally, keeping an animal in optimal to slightly lean body condition has been shown to decrease the risk of development of OA and to aid management of dogs with OA.

Diagnosis of urinary tract infections

Urinary tract infections (UTIs) are a common cause of urinary tract disease and may be associated with systemic disease. Diagnosis cannot be made on urinalysis and other findings alone. A urine culture is the "gold standard" for diagnosis of UTI. Antimicrobial susceptibility testing performed as part of a urine culture aids in selection of appropriate treatment for patients with confirmed bacterial UTI.

Update: management of calcium oxalate uroliths in dogs and cats

Calcium oxalate has become the most common mineral occurring in canine and feline uroliths. Although calcium oxalate urolith formation may be a consequence of metabolic disease, the underlying cause is not identified in many dogs and cats. Currently, there is no successful medical dissolution protocol, and calcium oxalate uroliths must be removed physically if causing problems. Effective preventative protocols are available for dogs and cats, although they are not uniformly successful.

Giant platelet disorder in the Cavalier King Charles Spaniel

OBJECTIVE

The aim of this study was to describe the clinical, functional, and morphologic characteristics of platelets in Cavalier King Charles Spaniel dogs (Cavaliers).

MATERIALS AND METHODS

Blood from 69 clinically normal Cavaliers was collected and anticoagulated with ethylenediamine-tetraacetic acid (EDTA) and citrate. Automated and manual platelet counts were obtained. Percent platelet aggregation in response to ADP (2, 4, 8, 16, and 32 microM) was determined. Electron microscopy was performed to examine platelet internal morphology and dense granule distribution. A cardiologist recorded the quality of murmurs.

RESULTS

Thrombocytopenia (<100,000/microL) was present in 51.43% (36/69) of Cavaliers. Macrothrombocytes (>3 microm) were present in 33.33% (22/69). Mean manual platelet count was 118,770/microL. Manual (EDTA blood) and automated (EDTA and citrated blood) methods of platelet counting were correlated. Prevalence of cardiac murmurs was 38% (26/69). There was no association between affected dogs and murmur, signalment, or coat color. Mean percent platelet aggregation was significantly higher in controls than in Cavaliers (79% vs 38%, p=0.001). Response to ADP was unaffected by thrombocytopenia, macrothrombocytes, murmur, or any combination thereof. Platelet electron microscopy showed normal and giant sized platelets with normal internal morphology.

CONCLUSIONS

A benign inherited giant platelet disorder affects approximately 50% of Cavalier King Charles Spaniels. It is characterized by thrombocytopenia, macrothrombocytes, or decreased platelet aggregation in response to ADP. Platelet ultrastructure is normal. Citrated or EDTA blood provides accurate platelet counts. Further studies are indicated to determine platelet glycoprotein structure and any association with mitral endocardiosis. Cavaliers may be useful models of inherited giant platelet disorders.

Effects of Diet on Urine Composition of Cats With Calcium Oxalate Urolithiasis

Ten client-owned cats with calcium oxalate (CaOx) urolithiasis were evaluated to determine the effect of diet on urine CaOx saturation. Two dietary treatments were evaluated in each cat: the diet consumed just prior to urolith detection and a canned diet formulated to prevent CaOx uroliths. This study revealed that hypercalciuria is a consistent abnormality in cats with CaOx urolith formation. When urolith-forming cats consumed a diet formulated to prevent urolith formation, activity product ratios for CaOx (which estimate the degree to which urine is saturated with CaOx) were significantly lower. These results suggest that consumption of an appropriately formulated urolith-prevention diet will reduce recurrence of CaOx urolithiasis.