Influence of preanalytical factors on feline proteinuria.

BACKGROUND: To date, little information is available about the effect of preanalytical factors on the urinary protein-to-creatinine (UPC) ratio in cats. OBJECTIVES: We aimed to evaluate the effect of a commercially available cat litter, creatinine measurements at three different dilutions of urine, and different storage conditions on the UPC ratio in cats. METHODS: Feline urine specimens were prospectively collected. Twenty-two whole-urine specimens were placed uncovered and in contact with cat litter for 1 hour; 25 urine supernatants were diluted 1:10, 1:20, and 1:100 for creatinine measurements. The correlation, difference, agreement, and concordance in classifying specimens according to International Renal Interest Society staging were determined. Storage effects on UPC ratios were assessed in specimens stored for 6 hours at +20℃ (n = 20), 1 week at +4℃ (n = 20), and 3 months at -20℃ (n = 25). Specimens were also subjected to four freeze-thaw cycles (n = 20). Results were compared, and clinical significance was assessed by comparing each UPC ratio to the inter-assay range of the baseline value. RESULTS: Exposure to cat litter did not affect UPC ratios. A positive proportional bias was found in the 1:100 dilution compared with the 1:20 dilution; however, concordance was high for all comparisons. At +20, +4℃, and after four repeated freeze-thaw cycles, UPC ratios were stable. Compared with baseline values, UPC ratios decreased (P < .01) after 8 and 12 weeks at -20℃. However, all UPC ratios were within the inter-assay variability of the baseline value. CONCLUSIONS: Exposure to cat litter did not affect UPC ratios, but further studies are necessary to evaluate other potential variables. The effects of the dilutions and storage conditions were clinically acceptable, although the 1:20 and 1:100 dilutions were not perfectly comparable.

Comparison of Protein Carbonyl (PCO), Paraoxonase-1 (PON1) and C-Reactive Protein (CRP) as Diagnostic and Prognostic Markers of Septic Inflammation in Dogs.

Reliable diagnostic and prognostic markers of sepsis are lacking, but essential in veterinary medicine. We aimed to assess the accuracy of C-Reactive Protein (CRP), protein carbonyls (PCO) and paraoxonase-1 (PON1) in differentiating dogs with sepsis from those with sterile inflammation and healthy ones, and predict the outcome in septic dogs. These analytes were retrospectively evaluated at admission in 92 dogs classified into healthy, septic and polytraumatized. Groups were compared using the Kruskal-Wallis test, followed by a Mann-Whitney U test to assess differences between survivors and non-survivors. Correlation between analytes was assessed using the Spearman's test, and their discriminating power was assessed through a Receiver Operating Characteristic (ROC) curve. PON1 and CRP were, respectively, significantly lower and higher in dogs with sepsis compared with polytraumatized and clinically healthy dogs (p < 0.001 for both the analytes), and also in dogs with trauma compared with healthy dogs (p = 0.011 and p = 0.017, respectively). PCO were significantly increased in septic (p < 0.001) and polytraumatized (p < 0.005) as compared with healthy dogs. PON1 and CRP were, respectively, significantly lower and higher in dogs that died compared with survivors (p < 0.001 for both analytes). Ultimately, evaluation of CRP and PON1 at admission seems a reliable support to diagnose sepsis and predict outcomes.

Identification of Protein Carbonyls (PCOs) in Canine Serum by Western Blot Technique and Preliminary Evaluation of PCO Concentration in Dogs With Systemic Inflammation.

In people, serum Protein Carbonyls (PCOs) increase during oxidative stress (OS) due to oxidative damage to proteins. OS is often associated with inflammation and especially with sepsis, a condition hard to diagnose in veterinary medicine because reliable markers are lacking. The aim of this study was to assess whether PCOs in canine serum may be detected by antibody-based methods such as Western Blotting (WB), and to preliminarily investigate the possible utility of this marker in dogs with inflammation. A serum sample oxidized in vitro was used to set up the method; the coefficient of variation obtained by repeated analysis varied from 24 to 36%. In order to assess whether the technique may cover the range of PCOs concentration detectable in routine practice, PCOs were measured in 4 healthy dogs and in 15 with inflammatory diseases, in some cases potentially associated with sepsis, as suggested by the results of other inflammatory markers such as C-Reactive Protein (CRP) and the anti-oxidant enzyme Paraoxonase 1 (PON-1): the concentration of PCOs was low in dogs with normal PON-1 activity, moderately increased in the majority of dogs with low-normal PON-1 activity, and severely increased in dogs with very low PON-1 activity. In conclusion this study demonstrates that PCOs, may be detected in canine serum, using antibody-based techniques such as WB. The preliminary results in dogs with and without systemic inflammation encourage further studies on the possible role of PCOs as inflammatory markers.

Haematological and biochemical reference intervals in healthy racing and retired Italian Greyhounds.

In view of the enormous variability of dog breeds, breed-specific reference intervals (RIs) are recommended for use in veterinary clinical decision-making. The aim of this study was to determine whether RIs of the general canine population may be applied to the Italian Greyhound (Piccoli Levrieri Italiani or PLI), and to generate breed-specific RIs, where appropriate. Sixty-three privately owned clinically healthy fasted dogs were examined. Routine haematology and biochemistry were performed on 58 enrolled patients using the ADVIA 120 haematology analyzer and the Cobas Mira system, respectively. Changes in haematological and biochemical parameters depending on sex, age and attitude (resting vs. running dogs) were investigated. The results of PLI were compared with the RIs of the general canine population. In those cases in which these RIs were not validated, new RIs were generated according to the guidelines of the American Society of Veterinary Clinical Pathology. Pre-existing RIs were considered valid based on the recommendations by the Clinical & Laboratory Standards Institute (CLSI). RIs were higher for mean corpuscular haemoglobin (MCH), mean cell haemoglobin concentration (MCHC), cell haemoglobin concentration mean (CHCM) and lower for large unstained cells (LUC). A wider discrepancy between pre-existing and newly established RIs was found for some ADVIA parameters regarding red blood cell (RBC) or reticulocyte morphology. For total protein and cholesterol the new RIs were wider than the pre-existing ones, while albumin, calcium and iron were higher. This study suggests that most of the RIs published in veterinary textbooks cannot be validated for PLIs.

Paraoxonase-1 activity evaluation as a diagnostic and prognostic marker in horses and foals.

BACKGROUND: In several species, paraoxonase-1 (PON-1) decreases during inflammation, because of the presence of oxidative stress; its measurement recently has been validated in horses, but its role as a clinical biomarker is unknown. OBJECTIVES: To evaluate sensitivity, specificity and likelihood ratio of PON-1 activity to identify systemic inflammatory response syndrome (SIRS)-positive horses or horses with a poor prognosis. ANIMALS: One hundred seventy-two blood samples from 58 sick horses from 3 different veterinary hospitals. METHODS: In a cross-sectional study, PON-1 activity was measured upon admission and at 24-hour intervals until discharge or death, and results were analyzed based on SIRS status and outcome. RESULTS: No statistically significant difference was found in median PON-1 activity between SIRS and non-SIRS cases or between survivors and non-survivors except for mares, in which PON-1 activity was significantly lower in SIRS-positive horses (P = .05). The sensitivity of PON-1 activity in identifying horses with SIRS or negative outcome was low (0.0%-46.2% depending on the examined group) but its specificity was high (87.0%-100.0%). However, when PON-1 is low, the likelihood of death is 2.40-3.89 times higher than the likelihood of survival. Repeated measurement of PON-1 after treatment does not predict outcome. CONCLUSIONS AND CLINICAL IMPORTANCE: Evaluation of PON-1 activity in horses with inflammation might be advisable in the future, but only low activity at admission may be relevant in predicting SIRS or negative outcome.

Hematologic and biochemical reference intervals in Shetland Sheepdogs.

BACKGROUND: Several breeds have physiological peculiarities that induce variations in reference intervals (RIs) compared with the general canine population. Shetland sheepdogs (SSs) are reported to be more predisposed to different diseases (eg, hyperlipidemia, gallbladder mucocele, and hypothyroidism). Consequently, a breed-specific approach is more often required. OBJECTIVES: The aim of this study was to determine whether the RIs of the general canine population could be applied to that of SSs, and to generate breed-specific RIs, where appropriate. METHODS: Sixty clinically healthy and fasted SSs (36% of the population registered at the Italian Breed association) were examined. Routine hematology and biochemistry analyses were performed. The transference method was used to compare the results of SSs with the RIs of the general canine population. When these RIs were not validated, new RIs were generated according to the guidelines of the American Society of Veterinary Clinical Pathology. Differences associated with sex, age, coat color, and whether used as a pet, a herding dog, or an agility dog were also investigated. RESULTS: The transference method validated for 30/38 SS RIs. For 6 of the remaining 8 variables, the difference with the claimed RIs could depend on preanalytical or analytical artifacts, whereas for glucose and total cholesterol, these differences could depend on breed peculiarities. However, in all SSs, the concentration of cholesterol was <12.95 mmol/L. Relevant differences associated with sex, age, coat color, and use were not found. CONCLUSIONS: This study suggests that breed-specific RIs should be used for glucose and cholesterol in SSs.

Validation of a paraoxon-based method for measurement of paraoxonase (PON-1) activity and establishment of RIs in horses.

BACKGROUND: Paraoxonase-1 (PON-1) is an antioxidant compound that is considered a negative acute phase protein. No information on the analytic performance of the paraoxon method for measuring PON-1 in horse serum is available. OBJECTIVES: The aim of this study was to validate a paraoxon-based method to measure PON-1 in horses and to establish RIs in healthy horses and foals. METHODS: Horses and foals classified as healthy after physical examination and routine biochemistry were used in the study. Serum PON-1 activity was measured with an automated spectrophotometer and an enzymatic method validated in other species. After the analytic validation (precision, accuracy, interference studies), RIs were determined using the Reference Value Advisor software. The possible sex-, age-, and breed-related differences were statistically investigated. RESULTS: The healthy study population included 120 horses and 55 foals. The paraoxon-based method was precise (CVs < 4.0%) and accurate (P < .001 in linearity under dilution and spike-recovery testing) but was affected by interference from mild bilirubinemia, severe lipemia, and hemoglobinemia. The RIs recorded in the whole population were 38.1-80.8 U/mL. According to the Harris and Boyd test, it would be advisable to use separate RIs only for adult females and for Warmblood and Trotter adults. CONCLUSIONS: This study demonstrated that the analytic performances of the paraoxon-based method for measurement of PON-1 in horses are acceptable. The PON-1 activity is lower in horses than in other domestic species. These results may provide a basis for further studies designed to establish whether healthy and sick horses can be correctly classified by using the PON-1 assay.