Luca Giori

Performances of different diagnostic tests for feline infectious peritonitis in challenging clinical cases

Objectives: Feline infectious peritonitis (FIP) can be difficult to diagnose. Histopathology is considered the gold standard test but immunohistochemistry (IHC) is mandatory to confirm/exclude the disease. This study aimed to assess the performances of tests carried out in vivo or at postmortem examination in challenging cases in which FIP was confirmed or excluded based on IHC or on adequate follow‐up. Methods: Twelve cases (four without FIP, eight with FIP) were retrospectively studied. Clinical findings, serum protein electrophoresis (SPE), analysis of the effusions (AE), antifeline coronavirus serology, serum concentration of α1‐acid glycoprotein (AGP) and histopathology were classified as consistent, doubtful or non‐consistent with FIP. Sensitivity, specificity and concordance (κ) with the final diagnosis were calculated. Results: Concordance was absent for serology (κ=−0·08) and AE (κ=−0·52), poor for histopathology (κ=0·09), fair for SPE (κ=0·25) and perfect for AGP (κ=1·00). Sensitivity was high for AGP (100%) and low for AE (50%), SPE (37·5%) and histopathology (37·5%). Specificity was high for AGP or histopathology (100%) and low for SPE (50%) and AE (0%). Clinical Significance: IHC must always be performed to confirm FIP. If this is not possible, when histopathology is controversial, elevated AGP concentrations may support the diagnosis of FIP.

Evaluation of factors that affect analytic variability of urine protein-to-creatinine ratio determination in dogs

OBJECTIVE To determine whether preanalytic and analytic factors affect evaluation of the urinary protein-to-creatinine (UPC) ratio in dogs. SAMPLE 50 canine urine samples. PROCEDURES The UPC ratio was measured to assess the intra-assay imprecision (20 measurements within a single session), the influence of predilution (1:10, 1:20, and 1:100) for urine creatinine concentration measurement, and the effect of storage at room temperature (approx 20°C), 4°C, and -20°C. RESULTS The coefficient of variation at room temperature determined with the 1:20 predilution was < 10.0%, with the highest coefficients of variation found in samples with a low protein concentration or low urine specific gravity. This variability could result in misclassification of samples with UPC ratios close to the thresholds defined by the International Renal Interest Society to classify dogs as nonproteinuric (0.2), borderline proteinuric (0.21 to 0.50), or proteinuric (> 0.51). A proportional bias was found in samples prediluted 1:10, compared with samples prediluted 1:20 or 1:100. At room temperature, the UPC ratio did not significantly increase after 2 and 4 hours. After 12 hours at room temperature and at 4°C, the UPC ratio significantly increased. The UPC ratio did not significantly change during 3 months of storage at -20°C. CONCLUSIONS AND CLINICAL RELEVANCE The intra-assay precision of the UPC ratio was sufficiently low to avoid misclassification of samples, except for values close to 0.2 or 0.5. The optimal predilution ratio for urine creatinine concentration measurement was 1:20. A 1:100 predilution is recommended in samples with a urine specific gravity > 1.030. The UPC ratio must be measured as soon as samples are collected. Alternatively, samples should be immediately frozen to increase their stability and minimize the risk of misclassification of proteinuria.

High-resolution gel electrophoresis and sodium dodecyl sulphate–agarose gel electrophoresis on urine samples for qualitative analysis of proteinuria in dogs

The aims of the current study were to assess whether sodium dodecyl sulphate–agarose gel electrophoresis (SDS-AGE) and high-resolution electrophoresis (HRE) can identify dogs with a urinary protein-to-creatinine ratio (UPC ratio) >0.2 and whether HRE can provide preliminary information about the type of proteinuria, using SDS-AGE as a reference method. HRE and SDS-AGE were conducted on 87 urine samples classified according to the International Renal Interest Society as non-proteinuric (NP; UPC ratio: <0.20; 32/87), borderline proteinuric (BP; UPC ratio: 0.21–0.50; 15/87), or proteinuric (P; UPC ratio: >0.51; 40/87). SDS-AGE and HRE were positive in 14 out of 32 and 3 out of 32 NP samples and in 52 out of 55 and 40 out of 55 samples with a UPC ratio >0.20, respectively. The concordance between HRE or SDS and UPC ratio was comparable (κ = 0.59; κ = 0.55). However, specificity (90%) and positive likelihood ratio (7.76) were higher for HRE than for SDS-AGE (56% and 2.16) while sensitivity was lower (73% vs. 94%). The analysis of HRE results revealed that a percentage of albumin >41.4% and an albumin/α1-globulin ratio (alb/α1 ratio) >1.46 can identify samples classified by SDS-AGE as affected by glomerular proteinuria while a percentage of α1-globulin >40.8% and an alb/α1 ratio <0.84 can identify samples classified by SDS-AGE as affected by tubular proteinuria. In conclusion, both SDS-AGE and HRE could misclassify samples with a UPC ratio higher or lower than 0.20. Therefore, UPC ratio must always be determined before conducting these tests. The percentage of albumin and α1-globulin or the alb/α1 ratio determined by HRE can provide preliminary information about the origin of proteinuria.

Accuracy of cytology in distinguishing adrenocortical tumors from pheochromocytoma in companion animals.

BACKGROUND The distinction between adrenocortical tumors and pheochromocytoma can be challenging using clinical findings, diagnostic imaging and laboratory tests. Cytology might be a simple, minimally invasive method to reach a correct diagnosis. OBJECTIVES The purpose of this study was to assess the accuracy of cytology in differentiating cortical from medullary tumors of the adrenal glands in dogs and cats. METHODS Cytologic key features of adrenocortical tumors and pheochromocytoma were defined by one reference author. Cytologic specimens from primary adrenal tumors were submitted to 4 cytopathologists who were asked to classify the tumors based on the previously defined key features without knowledge of previous classification. RESULTS Twenty specimens from histologically confirmed adrenal tumors (Group 1) and 4 specimens from adrenal tumors causing adrenal-dependent Cushings syndrome (Group 2) were evaluated by the 4 cytopathologists. Accuracy in differentiating cortical from medullary origin ranged from 90% to 100%, with a Kappa coefficient of agreement between cytopathologists of 0.95. CONCLUSIONS The origin of an adrenal tumor can be easily determined by cytology alone in many cases. However, cytology was not reliable in distinguishing benign from malignant neoplasia. Additional studies are needed to assess possible risks and complications associated with fine-needle biopsy of adrenal tumors in dogs and cats.

Role of Hepcidin in Iron Metabolism and Potential Clinical Applications

The relatively recent discovery of hepcidin has stimulated renewed research interest in iron metabolism and iron-related disorders, emphasizing the importance of this hormone in many normal and pathologic processes. Important questions still remain to be answered; however, research to date offers promising diagnostic and therapeutic implications for both humans and veterinary species.

Serum paraoxonase-1 activity in neonatal calves : age related variations and comparison between healthy and sick animals

Early detection of inflammation in neonatal calves allows early intervention, which may reduce mortality. Paraoxonase-1 (PON1) is a negative acute phase protein in humans. The aims of this study were to investigate age-related variability in serum PON1 activity and its clinical usefulness in neonatal calves. In healthy calves (n=9), PON1 activity increased with age from 2 to 21 days of age. There was no significant increase in PON1 activity in healthy calves from days 21 to 120 (n=15), but PON1 activity was significantly higher in adult cattle (n=45). In sick calves, serum PON1 was significantly lower in calves <7 days of age with diarrhoea (n=8) and in calves >28- to 120-days-old with respiratory disease (n=8) in comparison with age matched controls (n=20 and n=15, respectively). These results support the role of PON1 as a negative acute phase protein in cattle.

Changes in Serum and Urine SAA Concentrations and Qualitative and Quantitative Proteinuria in Abyssinian Cats with Familial Amyloidosis: A Five‐year Longitudinal Study (2009–2014)

Background Diagnosis of familial amyloidosis (FA) in Abyssinian cats usually is made on postmortem examination. Hypothesis/Objectives Sequential analysis of serum SAA (sSAA), urinary SAA (uSAA), urinary protein:creatinine (UPC) ratio, or sodium‐dodecylsulfate agarose gel electrophoresis (SDS‐AGE) may facilitate early identification of cats with FA. Animals Twenty‐three Abyssinian cats belonging to cattery A or B (low and high prevalence of FA, respectively). Methods Prospective longitudinal study using 109 blood and 100 urine samples collected over 4‐year period every 4 months, if possible, or more frequently in case of illness. Cats that died during study were necropsied. Health status of live cats was checked 5 years after enrollment. Serum amyloid A (sSAA) and urinary SAA (uSAA) were measured using ELISA kit. The UPC ratio and SDS‐AGE also was performed. Results Familial amyloidosis was not identified in cattery A, whereas 7/14 cats from cattery B had FA. Serum amyloid A concentrations were not significantly different between cats in catteries A and B or between cats with or without FA, despite frequent peaks in cats from cattery B. Conversely, uSAA was significantly higher in cattery B, especially in the terminal phases of FA. Proteinuria occasionally was found in cats from both catteries, especially in those with FA. Urine protein electrophoresis identified mixed proteinuria only in cats with FA. Conclusions and Clinical Importance Serum amyloid A and UPC ratio are not helpful for early identification of Abyssinian cats with FA. Conversely, increases in uSAA with or without mixed proteinuria may be found before onset of clinical signs in cats with FA.