Objective—To establish comprehensive reference ranges for plasma amino acid and whole blood taurine concentrations in healthy adult cats eating commercial diets and to evaluate the relationships of age, sex, body weight, body condition score (BCS), dietary protein concentration, and dietary ingredients with plasma amino acid and whole blood taurine concentrations.
Animals—120 healthy adult cats.
Procedures—Blood samples and a complete health and diet history were obtained for each cat, and reference intervals for plasma amino acid and whole blood taurine concentrations were determined. Results were analyzed for associations of age, breed, sex, body weight, BCS, use of heparin, sample hemolysis and lipemia, dietary protein concentrations, and dietary ingredients with amino acid concentrations.
Results—95% reference intervals were determined for plasma amino acid and whole blood taurine concentrations. A significant difference in amino acid concentrations on the basis of sex was apparent for multiple amino acids. There was no clear relationship between age, BCS, body weight, and dietary protein concentration and amino acid concentrations. Differences in amino acid concentrations were detected for various dietary ingredients, but the relationships were difficult to interpret.
Conclusions and Clinical Relevance—This study provided data on plasma amino acid and whole blood taurine concentrations for a large population of adult cats eating commercial diets. Plasma amino acid and whole blood taurine concentrations were not affected by age, BCS, or body weight but were affected by sex and neuter status. Dietary protein concentration and dietary ingredients were not directly associated with plasma amino acid or whole blood taurine concentrations.
Objective—To develop robust reference intervals for hematologic and serum biochemical variables by use of data derived from free-ranging bottlenose dolphins (Tursiops truncatus) and examine potential variation in distributions of clinicopathologic values related to sampling sites' geographic locations.
Animals—255 free-ranging bottlenose dolphins.
Procedures—Data from samples collected during multiple bottlenose dolphin capture-release projects conducted at 4 southeastern US coastal locations in 2000 through 2006 were combined to determine reference intervals for 52 clinicopathologic variables. A nonparametric bootstrap approach was applied to estimate 95th percentiles and associated 90% confidence intervals; the need for partitioning by length and sex classes was determined by testing for differences in estimated thresholds with a bootstrap method. When appropriate, quantile regression was used to determine continuous functions for 95th percentiles dependent on length. The proportion of out-of-range samples for all clinicopathologic measurements was examined for each geographic site, and multivariate ANOVA was applied to further explore variation in leukocyte subgroups.
Results—A need for partitioning by length and sex classes was indicated for many clinicopathologic variables. For each geographic site, few significant deviations from expected number of out-of-range samples were detected. Although mean leukocyte counts did not vary among sites, differences in the mean counts for leukocyte subgroups were identified.
Conclusions and Clinical Relevance—Although differences in the centrality of distributions for some variables were detected, the 95th percentiles estimated from the pooled data were robust and applicable across geographic sites. The derived reference intervals provide critical information for conducting bottlenose dolphin population health studies.
Objective—To compare effects of 3.8% sodium citrate and anticoagulant citrate dextrose solution National Institutes of Health formula A (ACD-A) on pH, extracellular ionized calcium (iCa) concentration, and platelet aggregation in canine platelet-rich plasma (PRP).
Sample Population—Samples from 12 dogs.
Procedures—Blood samples were collected into 3.8% sodium citrate (dilution, 1:9) and ACD-A (dilution, 1:5). Platelet function, pH, and iCa concentration were evaluated in PRP. Platelet agonists were ADP, γ-thrombin, and convulxin; final concentrations of each were 20μm, 100nM, and 20nM, respectively. Washed platelets were used to evaluate effects of varying the pH and iCa concentration.
Results—Mean pH and iCa concentration were significantly greater in 3.8% sodium citrate PRP than ACD-A PRP. Platelet aggregation induced by ADP and γ-thrombin was markedly diminished in ACD-A PRP, compared with results for 3.8% sodium citrate PRP. Anticoagulant had no effect on amplitude of convulxin-induced platelet aggregation. In washed platelet suspensions (pH, 7.4), there were no differences in amplitude of platelet aggregation induced by convulxin or γ-thrombin at various iCa concentrations. Varying the pH had no effect on amplitude of aggregation induced by convulxin or γ-thrombin, but the aggregation rate increased with increasing pH for both agonists.
Conclusions and Clinical Relevance—Aggregation of canine platelets induced by ADP and γ-thrombin was negligible in ACD-A PRP, which suggested an increase in extraplatelet hydrogen ion concentration inhibits signaling triggered by these agonists but not by convulxin. Choice of anticoagulant may influence results of in vitro evaluation of platelet function, which can lead to erroneous conclusions.
Objective—To evaluate the usefulness of an antibody detection ELISA and protein electrophoresis (PE) for diagnosing Encephalitozoon cuniculi (ECUN) infection in pet rabbits.
Animals—203 pet rabbits.
Procedures—Serum and plasma samples from pet rabbits were submitted from veterinary clinics within the United States. Participating veterinarians completed a questionnaire that was used to classify rabbits as clinically normal (n=33), suspected of having an ECUN infection (103), or clinically abnormal but not suspected of having an ECUN infection (67). An ELISA for detection of serum or plasma IgG against ECUN was developed by use of commercially available reagents. Results of the ELISA and PE were used to detect ECUN infection.
Results—A high seroprevalence of antibody against ECUN was detected in all 3 groups of rabbits. In rabbits suspected of having an ECUN infection, the mean IgG titer was 1.7 times as high as the values in the other rabbit groups. Rabbits suspected of having an ECUN infection and those that were simply clinically abnormal had a higher concentration of γ-globulins than clinically normal rabbits. This increase in globulins concentration was accompanied by a decrease in the albumin-to-globulin ratio. Results of the ELISA and PE were significantly different between clinically normal rabbits and those suspected of having an ECUN infection.
Conclusions and Clinical Relevance—The combination of an ELISA and PE may aid in the diagnosis of ECUN infection in pet rabbits.
Impact for Human Medicine—Because ECUN is a potential zoonotic agent, diagnostic methods for pet rabbits need to be improved to protect human health.
Objective—To assess platelet count, mean platelet volume (MPV), metabolic characteristics, and platelet function in a dimethyl sulfoxide (DMSO)–stabilized canine frozen platelet concentrate (PC).
Sample Population—11 units of a commercial frozen PC in 6% DMSO and fresh plateletrich plasma from 6 healthy control dogs.
Procedures—PCs were thawed, and the following data were collected: thaw time, platelet count, MPV, pH, PCO2, and PO2 and HCO3−, glucose, and lactate content. Phosphatidylserine translocation was determined by use of flow cytometry. Fresh platelet-rich plasma from healthy dogs served as a source of control platelets for flow cytometric analysis.
Results—At thaw, the platelet count in the frozen PC ranged from 243,000 to 742,000 platelets/μL. Median platelet count of paired samples was 680,000 platelets/μL and decreased significantly to 509,000 platelets/μL at 2 hours after thaw. Median MPV at thaw was 11.15 femtoliters and was stable after 2 hours. Compared with fresh platelets, frozen PC had increased amounts of phosphatidylserine in the outer leaflet of the platelet membrane in the resting (ie, not treated with thrombin) state (19% vs 99%, respectively) and alterations in cellular morphology, all of which were consistent with platelet activation.
Conclusions and Clinical Relevance—Results of this in vitro study indicated that there was a decrease in platelet quantity and function as well as an increase in platelet activation during the freeze-and-thaw process in DMSO-stabilized canine frozen PC. In vivo effects on PC remain to be determined.
Objective—To determine whether Labrador Retrievers participating in field trials develop respiratory alkalosis and hypocapnia primarily in conditions of high ambient temperatures.
Animals—16 Labrador Retrievers.
Procedures—At each of 5 field trials, 5 to 10 dogs were monitored during a test (retrieval of birds over a variable distance on land [1,076 to 2,200 m]; 36 assessments); ambient temperatures ranged from 2.2° to 29.4°C. For each dog, rectal temperature was measured and a venous blood sample was collected in a heparinized syringe within 5 minutes of test completion. Blood samples were analyzed on site for Hct; pH; sodium, potassium, ionized calcium, glucose, lactate, bicarbonate, and total CO2 concentrations; and values of PvO2 and PvCO2. Scatterplots of each variable versus ambient temperature were reviewed. Regression analysis was used to evaluate the effect of ambient temperature (≤ 21°C and > 21°C) on each variable.
Results—Compared with findings at ambient temperatures ≤ 21°C, venous blood pH was increased (mean, 7.521 vs 7.349) and PvCO2 was decreased (mean, 17.8 vs 29.3 mm Hg) at temperatures > 21°C; rectal temperature did not differ. Two dogs developed signs of heat stress in 1 test at an ambient temperature of 29°C; their rectal temperatures were higher and PvCO2 values were lower than findings in other dogs.
Conclusions and Clinical Relevance—When running distances frequently encountered at field trials, healthy Labrador Retrievers developed hyperthermia regardless of ambient temperature. Dogs developed respiratory alkalosis and hypocapnia at ambient temperatures > 21°C.
Objective—To evaluate the use of EDTA tubes for collection of blood samples for assays of secondary hemostasis in dogs.
Animals—108 dogs of various ages, breeds, and sexes (19 healthy and 89 with abnormalities of secondary hemostasis).
Procedures—Blood samples were collected via cephalic venipuncture and transferred to sodium citrate tubes and EDTA tubes. Plasma was harvested from each type of tube for assays of concentrations of fibrinogen and D-dimer as well as prothrombin time, activated partial thromboplastin time, and antithrombin activity. Intra-assay and interassay precision and correlation coefficients for all hemostatic tests were calculated for each type of plasma sample. The effect of storage conditions on assay results for the 2 types of plasma samples was also evaluated.
Results—Results of hemostatic tests were highly correlated between citrated and EDTA-treated plasma samples. Intra-assay imprecision for all hemostatic tests with the exception of D-dimer concentration was < 10% for both citrated and EDTA-treated plasma samples; interassay imprecision was higher for EDTA-treated versus citrated plasma samples. Storage of plasma samples for 1 hour did not result in significantly different assay results for either type of plasma sample, but storage for 2 hours significantly affected values for EDTA-treated plasma samples.
Conclusions and Clinical Relevance—Although evaluation of the sensitivity and specificity of hemostatic tests that use EDTA-treated plasma samples is required, EDTA may be a suitable alternative to sodium citrate as an anticoagulant for use in hemostatic testing in conditions in which tests could be performed within 1 hour after sample collection.
Objective—To develop a reticulocyte classification scheme, optimize an avian reticulocyte staining protocol, and compare the percentages of reticulocyte types with polychromatophil percentage in blood samples from birds.
Sample Population—Blood samples from a red-tailed hawk and 31 ill birds.
Procedures—A single blood sample obtained from a red-tailed hawk (Buteo jamaicensis) was used to optimize the staining protocol. For optimization of the staining protocol, 4 dilutions of whole blood with new methylene blue stain and 4 incubation times were evaluated. From samples submitted for avian CBCs, EDTA-anticoagulated whole blood samples from 31 ill birds were randomly selected and examined to compare polychromatophil and reticulocyte percentages. Reticulocyte staining was performed in all samples by use of a 1:3 (whole blood to new methylene blue) dilution with incubation for 10 minutes at room temperature (approx 22°C); reticulocytes were assessed as a percentage of 1,000 RBCs by 2 independent observers. In Wright-Giemsa–stained blood smears, a polychromatophil percentage was similarly determined.
Results—4 avian reticulocyte types were defined: ring-form reticulocytes, aggregate reticulocytes, and 2 subcategories of punctate reticulocytes. A reticulocyte-staining protocol was optimized. Interobserver and intraobserver variations in assessment of reticulocyte and polychromatophil percentages were not significant. A strong positive correlation (Spearman coefficient of rank correlation [ρ] = 0.978) was identified between the percentage of polychromatophils and the percentage of ring-form reticulocytes.
Conclusions and Clinical Relevance—Results indicated that quantification of ring-form reticulocytes provides an accurate assessment of erythrocyte regenerative capacity in birds.
Objective—To compare prothrombin time (PT), activated partial thromboplastin time (APTT), and fibrinogen concentration in canine blood samples collected via an indwelling IV catheter and direct venipuncture.
Animals—35 dogs admitted to an intensive care unit that required placement of an IV catheter for treatment.
Procedures—Blood samples were collected via IV catheter and direct venipuncture at the time of catheter placement and 24 hours after catheter placement. Prothrombin time, APTT, and fibrinogen concentration were measured.
Results—5 dogs were excluded from the study; results were obtained for the remaining 30 dogs. Agreement (bias) for PT was −0.327 seconds (limits of agreement, −1.350 to 0.696 seconds) and 0.003 seconds (limits of agreement, −1.120 to 1.127 seconds) for the 0- and 24-hour time points, respectively. Agreement for APTT was −0.423 seconds (limits of agreement, −3.123 to 2.276 seconds) and 0.677 seconds (limits of agreement, −3.854 to 5.207 seconds) for the 0- and 24-hour time points, respectively. Agreement for fibrinogen concentration was −2.333 mg/dL (limits of agreement, −80.639 to 75.973 mg/dL) and −1.767 mg/dL (limits of agreement, −50.056 to 46.523 mg/dL) for the 0- and 24-hour time points, respectively.
Conclusions and Clinical Relevance—Agreement between the 2 techniques for sample collection was clinically acceptable for PT, APTT, and fibrinogen concentration at time 0 and 24 hours. It is often difficult or undesirable to perform multiple direct venipunctures in critically ill patients. Use of samples collected via an IV catheter to monitor PT and APTT can eliminate additional venous trauma and patient discomfort and reduce the volume of blood collected from these compromised patients.
Objective—To determine the lipid composition and electrophoretic pattern of plasma lipoproteins in samples obtained from healthy 1-humped camels (Camelus dromedarius).
Animals—34 healthy camels raised under similar farming and dietary conditions.
Procedures—Plasma samples were subjected to density-gradient ultracentrifugation for separation of plasma lipoproteins, including very-low-density lipoproteins (VLDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL). Purity of the separation was assessed by use of polyacrylamide gel disk electrophoresis. Concentrations of triglycerides, cholesterol, and phospholipids were measured in each lipoprotein fraction, and lipoprotein electrophoretic patterns were determined in plasma samples.
Results—Phospholipid was the major constituent of VLDL (mean ± SD concentration, 10.62 ± 1.2 mg/dL), LDL (24.66 ± 3.12 mg/dL), and HDL (38.08 ± 0.76 mg/dL). Low-density lipoprotein, VLDL, and HDL were important plasma lipoprotein carriers for cholesterol (67.94 ± 9.51%), triglyceride (55.83 ± 7.81%), and phospholipid (51.91 ± 1.55%), respectively. On the basis of electrophoresis results, relative percentages of α- and β-lipoproteins were 31.72 ± 4.88% and 68.3 ± 4.68%, respectively.
Conclusions and Clinical Relevance—The lipoprotein profile in 1-humped camels differed substantially from that of other ruminants. Results may be useful in the evaluation of metabolic disorders in camels.