Fernando Tecles

Serum concentrations of acute phase proteins in dogs with leishmaniasis

The concentrations of haptoglobin, C-reactive protein and ceruloplasmin were measured in symptomatic and asymptomatic dogs naturally infected by Leishmania infantum, and in healthy uninfected dogs to determine the potential value of these proteins for the diagnosis and prognosis of leishmaniasis. The concentrations of the acute phase proteins were significantly higher in the dogs with leishmaniasis than in the control dogs, and the concentration of C-reactive protein was significantly higher in the symptomatic dogs than in the asymptomatic dogs. There were no correlations between the acute phase proteins and the gamma globulins, the albumin/globulin ratio or the titre of anti-leishmanial antibodies.

Acute phase protein response in goats

Acute phase proteins (APPs) are important diagnostic indicators of inflammatory disturbances in animals. The objectives of the current study were to validate analytical methods for measuring haptoglobin (Hp), serum amyloid A (SAA), acid soluble glycoprotein (ASG), fibrinogen, and albumin concentrations in goats and to evaluate their response to an inflammatory stimulus in this species. Intra- and interassay coefficients of variation (CVs) were in the range 0.07–9.31% and 1.83–12.68%, respectively, for all APPs and showed good precision. All assays determined APPs in a linear manner at different sample dilutions with high correlation coefficients with the exception of fibrinogen, which was measured by the heat precipitation method. Subcutaneous injection of turpentine oil induced an increase in Hp, SAA, ASG, and fibrinogen serum concentrations and a decrease in albumin concentration.

Serum paraoxonase 1 (PON1) measurement: an update

Paraoxonase 1 (PON1) is a widely studied enzyme based on its protective role against poisoning by organophosphate (OP) metabolites of specific OP insecticides and in vascular disease, as well as its use as biomarker of diseases involving oxidative stress, inflammation and liver diseases.This review provides an update about the current knowledge in the field of the analytical procedures that are used for PON1 measurements. It will be specially focused on: (a) characteristics of the different substrates used for measuring PON1, with emphasis in four aspects: toxicity, polymorphism influence, rate of hydrolysis and diagnostic performance. And (b) the technical aspects of PON1 assays, in which the reagents and reaction conditions, sources of variation, quality control systems, equipment and interferences with other esterases will be discussed.The information provided in this review can contribute to a more accurate and safe measurements of PON1 in laboratories and encourage researchers to explore the wide areas of PON1 in veterinary medicine that are still unknown.

Validation of spectrophotometric assays for serum paraoxonase type-1 measurement in dogs.

OBJECTIVE To evaluate and validate 3 spectrophotometric assays for measuring serum activity of paraoxonase type-1 (PON1), an enzyme associated with high-density lipoproteins, in dogs. ANIMALS 22 healthy adult dogs and 10 dogs with eccentrocytosis. PROCEDURES 2 methods were adapted for use in 96-well microplates with phenyl acetate and 5-thiobutyl butyrolactonase as substrates, and 1 was adapted for use in an automated analyzer with p-nitrophenyl acetate as substrate. Blood samples were collected from all dogs, serum was harvested, and serum PON1 activity was measured with each method. RESULTS Imprecision was low for all 3 methods, with the exception of interassay imprecision for 5-thiobutyl butyrolactonase, and results were linear across serial sample dilutions. The 3 methods were able to detect low PON1 activity when EDTA was used for blood sample collection, yielded lower PON1 values in sick dogs with eccentrocytosis than in healthy dogs, and yielded highly correlated results. CONCLUSIONS AND CLINICAL RELEVANCE The methods described here may allow a wider use of PON1 activity as a biomarker of oxidative stress in dogs in clinical and research settings. Results of each method were robust and precise (with the exception of the interassay values for the lactonase method), and the methods were easy to set up in a laboratory.

C-reactive protein measurement in canine saliva

An established time-resolved immunofluorometric assay designed for measurement of C-reactive protein (CRP) in canine blood was evaluated and validated for use in canine saliva. C-reactive protein was measured in saliva specimens from 5 healthy dogs before and after the injection of casein and in 37 dogs with different disease conditions. The analytical and functional limits of detection were 0.000053 μg/ml and 0.0091 μg/ml, respectively, and intra- and interassay coefficients of variation ranged between 6.7–9.9% and 8.5–16.5%, respectively. A recovery experiment showed no significant disagreement between detected values and expected ones, and saliva CRP concentration was measured in a linear and proportional manner. A positive correlation was found between CRP levels obtained in saliva and serum samples in the experimental (R 2 = 0.76) and clinical studies (R 2 = 0.70). The assay was able to detect significant differences between salivary CRP levels in healthy dogs and dogs with inflammatory processes. These results suggest that saliva can be used for CRP measurement in dogs. The use of saliva presents the advantage of an easier and less stressful sampling method for the animals, which might be performed outside of hospital environments.

Serum acute phase protein concentrations in female dogs with mammary tumors.

Acute phase proteins (APPs) are proteins whose concentrations in serum change after any inflammatory stimulus or tissue damage. The aim of the current study was to evaluate 3 positive APPs (C-reactive protein, serum amyloid A, and haptoglobin) and 1 negative APP (albumin) in female dogs with mammary neoplasia. Acute phase proteins were studied in 70 female dogs aged 8–12 years in the following groups: healthy (n = 10); mammary tumors in stages I (n = 19), II (n = 5), III (n = 6), IV (n = 5), and V (n = 7); and with mammary neoplasia plus a concomitant disease (n = 18). In animals with mammary neoplasia, significant increases of positive APPs were only detected in those that had metastasis or a neoplasm with a diameter greater than 5 cm and ulceration. Dogs with mammary neoplasia and a concomitant disease also had high C-reactive protein concentrations. Albumin concentration was decreased in animals with metastasis and with a concomitant disease. The results of the present study indicate that the acute phase response could be stimulated in female dogs with mammary gland tumors because of different factors, such as metastasis, large size of the primary mass, and ulceration or secondary inflammation of the neoplasm.

Critical differences of acute phase proteins in canine serum samples.

The critical difference values for acute phase proteins in canine serum samples were established on a week-to-week basis. Blood samples from 11 apparently clinically healthy dogs were collected once weekly for five consecutive weeks. For each protein the total variance of analytical results was divided into intraindividual variance (S(Intra)(2)), interindividual variance (S(Inter)(2)), and analytical variance (S(Analytical)(2)). The critical difference (d(K)) was then calculated as d(k)=22(S(Intra)(2)+S(Analytical)(2)). The critical difference values were 1.95 g/L for haptoglobin, 4.85 mg/L for C-reactive protein, and 0.016 DeltaAbs/min for ceruloplasmin. When used in conjunction with the corresponding reference interval, critical difference values can be an aid in correctly interpreting acute phase protein results, by determining whether observed differences between two consecutive measurements in individual animals are due to natural variation or due to disease therapy or experimental procedures.

Effect of weight loss on inflammatory biomarkers in obese dogs

The objective of this study was to evaluate the effects of weight loss on selected serum inflammatory biomarkers in obese dogs. An experimentally induced bodyweight reduction of approximately 2.5%/week was accompanied by significant decreases in metabolic markers of obesity (lipidic profile, fructosamine, and insulin-like growth factor-1). The concentrations of acute phase proteins and of selected cytokines remained within reference ranges in obese dogs during weight loss, suggesting that significant inflammation was not a major component of this experimental model. However, adiponectin concentrations increased following the period of weight loss suggesting reduced susceptibility of these animals to obesity-related inflammation.

Validation of an Automated Method for Salivary Alpha-Amylase Measurements in Pigs (Sus Scrofa Domesticus) and its Application as a Stress Biomarker

The aim of the current study was to validate an automated spectrophotometric method for salivary alpha-amylase measurement in pigs and evaluate its possible application as a noninvasive stress biomarker. The analytical validation included intra- and interassay precision, linearity under dilution, and limit of detection. In addition, to study the possible use of salivary alpha-amylase as a possible stress marker, 12 crossbred growing pigs of 3–4 months of age were subjected to restraint stress by a nasal snare for at least 1 min, and saliva samples were obtained at different time points. The results of analytical validation indicated that the method was precise and able to measure alpha-amylase in a linear manner. The results obtained in the stress test showed a significant increase in salivary alpha-amylase activity. Although other factors influencing this enzyme activity should be studied, these preliminary results indicate that salivary alpha-amylase could be a reliable biomarker of stress in pigs.

Serum butyrylcholinesterase and paraoxonase 1 in a canine model of endotoxemia: effects of choline administration.

Butyrylcholinesterase (BChE) and paraoxonase 1 (PON1) are two serum enzymes synthesized by the liver that are related with inflammation. The main objectives of this study were to determine changes in serum BChE and PON1 by using a canine model of endotoxemia, and to evaluate whether choline alters BChE and PON1 activities during inflammation. For this purpose, a total of 20 mongrel dogs were divided into four groups: control, choline (C), lipopolysaccharide (LPS), and LPS+C. Dogs in the control group were injected with 0.9% NaCl (0.2 ml/kg, i.v.). Dogs in C and LPS+C groups received choline chloride (20 mg/kg, i.v., three times with 4 h intervals). Endotoxin was injected (0.02 mg/kg, i.v., once) to the dogs of LPS and LPS+C groups. Statistically significant decreases in BChE and PON1 activities in LPS group were detected 24 and 48 h post injection, respectively. No statistically significant changes in BChE and PON1 activities at different times were detected in control, C, or LPS+C groups. In conclusion, the data obtained in present study revealed a decrease in serum BChE and PON1 activities in dogs during experimentally induced endotoxemia and that choline administration attenuates these changes.