F. Porciello

Physical exercise, oxidative stress and muscle damage in racehorses

Since it has been suggested that lipid peroxidation following free radical overproduction may be one of the causes of physical exercise-induced myopathies and hemolysis in horses, we looked for the possible relationships between these phenomena and muscle fiber damage. We use a homogeneous group of Maremmana stallions which, after a 3-month training period, underwent a series of physical exercises of increasing intensity. We determined the contents of malondialdehyde (MDA), one of the main lipid peroxidation end-products, and glutathione the substrate of one of the most important free radical scavenger enzymes. We also measured creatine phosphokinase and serum lactate dehydrogenase isoenzyme activities whose modification may be indicative of muscle fiber damage. The results obtained indicated that the physical exercise we adopted was able to modify both MDA and glutathione contents in blood. However, its effect on some LDH isoenzyme activities suggested possible damage to tissues other than muscle.

Cardiac troponin I is elevated in dogs and cats with azotaemia renal failure and in dogs with non‐cardiac systemic disease

OBJECTIVE To determine if dogs and cats with renal failure, or other severe non-cardiac disease, and no antemortem evidence of cardiac disease on basic clinical evaluation, have elevated levels of cardiac troponin I (cTnI). DESIGN Cross-sectional study using 56 dogs and 14 cats with primary non-cardiac disease (39 dogs with azotaemic renal failure, 14 cats with azotaemic renal failure, 17 dogs with non-cardiac systemic disease); 7/25 dogs and 6/14 cats had murmurs detected on physical examination. Serum or heparinised plasma was collected and analysed for cTnI. RESULTS Cardiac troponin I concentrations were elevated above reference intervals in 70% of dogs and 70% of cats with azotaemic renal failure and in 70% of dogs with a variety of systemic non-cardiac diseases. Cardiac troponin I concentrations did not correlate with the degree of azotaemia, presence of murmurs, hypertension or type of non-cardiac illness. CONCLUSIONS Cardiac troponin I concentration is often elevated in dogs and cats with azotaemic renal failure and in dogs with other systemic non-cardiac illness, suggesting that these conditions often result in clinically inapparent myocardial injury or possibly altered elimination of cTnI.

Myosin‐Binding Protein C DNA Variants in Domestic Cats (A31P, A74T, R820W) and their Association with Hypertrophic Cardiomyopathy

BACKGROUND Two mutations in the MYBPC3 gene have been identified in Maine Coon (MCO) and Ragdoll (RD) cats with hypertrophic cardiomyopathy (HCM). OBJECTIVE This study examined the frequency of these mutations and of the A74T polymorphism to describe their worldwide distribution and correlation with echocardiography. ANIMALS 1855 cats representing 28 breeds and random-bred cats worldwide, of which 446 underwent echocardiographic examination. METHODS This is a prospective cross-sectional study. Polymorphisms were genotyped by Illumina VeraCode GoldenGate or by direct sequencing. The disease status was defined by echocardiography according to established guidelines. Odds ratios for the joint probability of having HCM and the alleles were calculated by meta-analysis. Functional analysis was simulated. RESULTS The MYBPC3 A31P and R820W were restricted to MCO and RD, respectively. Both purebred and random-bred cats had HCM and the incidence increased with age. The A74T polymorphism was not associated with any phenotype. HCM was most prevalent in MCO homozygote for the A31P mutation and the penetrance increased with age. The penetrance of the heterozygote genotype was lower (0.08) compared with the P/P genotype (0.58) in MCO. CONCLUSIONS AND CLINICAL IMPORTANCE A31P mutation occurs frequently in MCO cats. The high incidence of HCM in homozygotes for the mutation supports the causal nature of the A31P mutation. Penetrance is incomplete for heterozygotes at A31P locus, at least at a young age. The A74T variant does not appear to be correlated with HCM.

Use of serum cistatin C determination as a marker of renal function in the dog.

Glomerular filtration rate (GFR) as an expression of renal function (RF), can be evaluated through the clearance of endogenous and exogenous substances. However, as this method must be validated for clinical veterinary practice, urea (sUr) and creatinine (sCr) serum levels are usually determined in order to evaluate RF. Since sUr and sCr values can also be influenced by extra-renal factors, research in human medicine (Randers and Erlandsen, 1997) over several years has led to consider serum levels of cystatin C (cCys-C) as a significant marker for RF. Cys-C is a low molecular weight (14 kD) basic protein of the cystatin superfamily, inhibitors of cystein-proteases, which is produced at a constant rate by all nucleated cells. Cys-C is filtered at the glomerular level and reabsorbed and catabolized completely by the cells of the proximal tubule, so much that its haematic concentration is not influenced by extra-renal factors (diet, muscular mass, etc.) (Randers and Erlandsen, 1997). Based on consideration of the data acquired on the clinical significance of sCys-C evaluation in humans (Aksun et al., 2004; Delanaye et al., 2003; Mars et al., 2003; Massey, 2004; Randers and Erlandsen, 1997) and from the limited reports in veterinary medicine, (Almy et al., 2002; Braun et al., 2002; Jensen et al., 2001), we wanted to verify whether CysC could also be determined in the blood serum of dogs by applying the same methodology used in human medicine and if its eventual variations could indicate decreased RF.

Transthoracic echocardiographically-guided interventional cardiac procedures in the dog

OBJECTIVES Interventional cardiac procedures are traditionally performed using fluoroscopy, or, more recently, transesophageal echocardiography (TEE). Neither modality is widely available to practicing cardiologists worldwide. We examined whether balloon valvuloplasty of pulmonic stenosis (PS) and transarterial occlusion of patent ductus arteriosus (PDA) in dogs could be performed safely with transthoracic echocardiography (TTE). ANIMALS A prospective consecutive case series of 26 client-owned dogs with PS (n = 10) and PDA (n = 16). METHODS The cardiovascular procedures were performed using TTE. Each dog was positioned on a standard echocardiography table in right lateral recumbency (dogs with PS) or left lateral recumbency (dogs with PDA). Guide wires, balloon catheters, Amplatz(®) Canine Ductal Occluder (ACDO) delivery sheaths, and ACDO were imaged by standard echocardiographic views optimized to allow visualization of the defects and devices. RESULTS Procedures were performed successfully without major complications in 20 dogs. In 2 dogs (German shepherds) with Type III PDA, ACDO placement was unsuccessful; 2 other German Shepherds were excluded from the procedure because their ductal diameters, measured echocardiographically, exceeded the limits of the maximal ACDO size. Two dogs weighing ≤3.5 kg had suboptimal echocardiographic visualization of the PDA and were considered too small for safe ACDO deployment. All intravascular devices at the level of the heart and great vessels appeared hyperechoic on TTE image and could be clearly monitored and guided in real-time. CONCLUSIONS We have demonstrated that TTE monitoring can guide each step of pulmonic balloon valvuloplasty and PDA occlusion without fluoroscopy.

Sleeping and resting respiratory rates in healthy adult cats and cats with subclinical heart disease

Sleeping and resting respiratory rates are commonly measured variables in patients with cardiac disease. However, little information is available on these variables in healthy client-owned cats or cats with subclinical heart disease (SHD). Therefore, we examined and characterized the sleeping respiratory rate (SRR) and resting respiratory rate (RRR) in 59 echocardiographically normal (EN) and 28 apparently healthy (AH) cats, and 54 SHD cats acquired by the cat owners in the home environment on eight to 10 separate occasions. The within-cat mean sleeping respiratory rate (SRRmean) in EN cats, AH cats and SHD cats with mild or moderate left atrial (LA) enlargement (as defined by quantiles of the ratio of the LA to the aorta [LA:AO]) was consistently <30 breaths/min; median SRRmean approximated 21 breaths/min. The SRRmean of SHD cats with severe LA enlargement sometimes exceeded 30 breaths/min, and was higher than SRRmean of other SHD cats (P <0.05). The within-cat mean resting respiratory rate was consistently higher than SRRmean (P <0.05). Age and geographic location, but not bodyweight, affected SRRmean in EN and AH cats. Within-cat SRR and within-cat RRR did not vary markedly from day-to-day, as evidenced by a low within-cat coefficient of variation. Data acquisition was considered easy or non-problematic by most participants. Our data provide useful guidelines for SRR and RRR, obtained in the home environment, in healthy cats and cats with SHD, and might prove useful in managing cats with clinical heart disease. Cats with SRRmean >30 breaths/min and cats with multiple SRR measurements >30 breaths/min likely warrant additional evaluation.

Serum Cystatin-C Evaluation in Dogs Affected by Different Diseases Associated or Not with Renal Insufficiency

Antognoni, M.T., Siepi, D., Porciello, F., Rueca, F. and Fruganti, G., 2007. Serum cystatin-C evaluation in dogs affected by different diseases associated or not with renal insufficiency. Veterinary Research Communications, 31(Suppl. 1), 269–271

Transesophageal Echocardiography as the Sole Guidance for Occlusion of Patent Ductus Arteriosus using a Canine Ductal Occluder in Dogs

Background Transcatheter occlusion of patent ductus arteriosus (PDA) is usually performed by fluoroscopy alone or together with transesophageal echocardiography (TEE). Transthoracic echocardiography (TTE) guidance has been used for deployment of Amplatz Canine Ductal Occluder (ACDO), but sometimes is limited by suboptimal acoustic windows. Transesophageal echocardiography can overcome such issues and provides higher image resolution at the level of the great vessels. Objectives To determine if TEE without fluoroscopy could be used to successfully perform ductal occlusion for the treatment of PDA in dogs. Animals Twenty client‐owned dogs with PDA. Methods A prospective consecutive case series of PDA occlusion was performed using only TEE guidance. Dogs were positioned in right lateral recumbency and the TEE probe was positioned to visualize the descending aorta, PDA, and pulmonary artery. The guide wire, long introducer sheath, and ACDO were imaged by TEE to direct deployment. Results Ductal occlusion was performed successfully without need for fluoroscopy and without complications in 19 dogs. One dog required a second larger ACDO because of embolization of the first device 18 hours after positioning. Conclusions and Clinical Importance We have demonstrated that TEE monitoring without concurrent fluoroscopy can guide each step of transcatheter ACDO embolization thereby providing an alternate method of visualization for this procedure. Use of TEE alone can reduce radiation exposure or is an option when fluoroscopy is not available, and, therefore, should be evaluated in a larger case series to better assess procedural failure rates.

Sleeping and resting respiratory rates in dogs with subclinical heart disease

OBJECTIVE To characterize sleeping respiratory rates (SRRs) and resting respiratory rates (RRRs), collected in the home environment, of dogs with subclinical heart disease that could result in left-sided congestive heart failure. DESIGN Prospective cross-sectional study. ANIMALS 190 adult dogs with subclinical left-sided heart disease. PROCEDURES Most dogs had mitral valve disease or dilated cardiomyopathy of various severities. Clients collected ten 1-minute SRRs or RRRs during a period ranging from 1 week to 6 months. Clinicians provided echocardiographic and medical data on each patient. RESULTS The within-dog mean SRR (SRRmean; 16 breaths/min) was significantly lower than the within-dog mean RRR (RRRmean; 21 breaths/min). Seven dogs had SRRmean and 33 dogs had RRRmean > 25 breaths/min; 1 dog had SRRmean and 12 dogs had RRRmean > 30 breaths/min; these dogs mostly had a left atrial (LA)-to-aortic ratio > 1.8. Dogs with moderate LA enlargement had a significantly higher SRRmean than did other dogs. However, median SRRmean for each of 4 levels of LA enlargement was < 20 breaths/min; median RRRmean for each of 4 levels of LA enlargement was < 25 breaths/min. Both within-dog SRR and RRR remained stable for 10 consecutive measurements. Treatment with cardiac medications or presence of pulmonary hypertension was not associated with SRRmean or RRRmean. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that dogs with confirmed subclinical left-sided heart disease of various severities generally had SRRmean < 25 breaths/min, which was infrequently exceeded at any time, and that SRR and RRR remained stable, regardless of individual within-dog SRRmean or RRRmean.

Sleeping respiratory rates in apparently healthy adult dogs

Respiratory rate monitoring of cardiac patients is recommended by many cardiologists. However, little objective data exist about respiratory rates in apparently healthy dogs when collected in the home environment. We measured sleeping respiratory rates (SRR) in apparently healthy dogs and compared sleeping and resting respiratory rates (RRR) with a cross-sectional prospective study. Participants collected 12-14 one-minute SRR over a period ranging from 1 week to 2 months on 114 privately owned adult dogs. Selected participants simultaneously collected RRR. Mean within-dog average SRR (SRR(mean)) was 13breaths per minute (breaths/min). No dog had SRR(mean) >23 breaths/min; three dogs had instantaneous SRR measurements >30 breaths/min. Dogs had higher RRR(mean) (19 breaths/min) than SRR(mean) (15 breaths/min) (P<0.05). Canine SRR(mean) was unaffected by age, bodyweight or geographic location. Data acquisition was considered relatively simple by most participants. This study shows that apparently healthy adult dogs generally have SRR(mean) <30 breaths/min and rarely exceed this rate at any time.