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Abstract

Objective—To determine diagnostic accuracy of using erythrocyte indices and polychromasia to identify regenerative anemia in dogs.

Design—Retrospective and prospective cross-sectional study.

Animals—4,521 anemic dogs.

Procedures—CBC results obtained between July 2002 and July 2008 by use of an automated laser-based flow cytometric hematology analyzer from dogs with Hct values ≤ 35% were retrieved. Sensitivity, specificity, accuracy, and predictive values of using erythrocyte indices and polychromasia to identify regeneration were determined, with a reticulocyte count > 65,000 reticulocytes/μL considered the gold standard. Similarly, 134 blood samples from anemic dogs were analyzed prospectively with an in-house electrical impedance analyzer.

Results—Of 4,387 dogs with samples analyzed retrospectively, 1,426 (32.5%) had regenerative anemia. Of these, 168 (11.8%) had macrocytic hypochromic anemia. High mean cell volume and low mean cell hemoglobin concentration had low sensitivity (11%), high specificity (98%), and moderate accuracy (70%) when used to identify regenerative anemia. Use of polychromasia alone had an accuracy of 77%, and use of polychromasia combined with a high RBC distribution width (RDW) had an accuracy of 79%. Results obtained with the in-house analyzer were similar.

Conclusions and Clinical Relevance—Results suggested that most regenerative anemias in dogs were not macrocytic hypochromic. Polychromasia, with or without high RDW, was a more accurate indicator than other erythrocyte indices of regenerative anemia. To avoid a false diagnosis of nonregenerative anemia, a blood smear should be evaluated in anemic dogs when a reticulocyte count is not available.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objectives

To investigate in vitro effects of ketosis and hyperglycemia on feline erythrocyte Heinz body formation, reduced glutathione (GSH) concentration, and D-and L-lactate production, and to identify potential metabolic mechanisms of oxidative stress in diabetic cats.

Design

Washed feline erythrocytes suspended in buffers containing normal or high glucose concentration were incubated with various concentrations of ketone bodies and tested at defined time intervals for Heinz bodies, GSH concentration, and D- and L-lactate production.

Animals

Three healthy female domestic cats.

Procedure

Erythrocytes were washed, suspended in buffers containing 5 mM glucose (simulates euglycemia) or 25 mM glucose (simulates hyperglycemia), and incubated with acetone (5 and 10 mM), acetoacetate (5 and 10 mM), or β-hydroxybutyrate (5 and 25 mM) for 24 hours at 37 C. Aliquots were stained with new methylene blue for Heinz bodies, and assayed spectrophotometrically for GSH and D- and L-lactate concentrations. Experiments were done in triplicate. Data were analyzed, using ANOVA with repeated measures.

Results

Neither high glucose concentration nor ketosis had direct effects on Heinz body formation or GSH values. Glutathione decreased to 89% of initial values over the 24-hour period in all samples. High glucose concentration also had no effect on erythrocyte D-lactate production; however, the rate of D-lactate production was slightly increased in samples containing 25 mM β-hydroxybutyrate. Linear L-lactate production confirmed metabolic viability of the erythrocyte suspensions. Samples in high glucose concentration produced L-lactate at a slightly higher (1.2×) rate than did samples in normal glucose concentration.

Conclusions

High glucose concentration and ketosis do not account directly for oxidative damage and glyoxalase induction in feline erythrocytes in vitro, although high concentrations of β-hydroxybutyrate may stimulate D-lactate formation. (Am J Vet Res 1996;57:463–467)

Free access
in American Journal of Veterinary Research

Abstract

Objective—To describe and quantify morphologic abnormalities in RBCs of mallards (Anas platyrhynchos) with experimentally induced zinc toxicosis.

Animals—120 female mallards.

Procedure—Farm-raised mallards (6 to 8 months old) were used in the study. On day 0, 60 ducks received shot pellets orally by gavage (mean dose of zinc, 0.97 g); another 60 ducks underwent the same procedure without administration of pellets. On day 15, Romanowsky-stained blood smears were prepared from 53 control and 45 zinc-treated ducks (smears were examined retrospectively). In each smear, 200 RBCs were examined and numbers of erythrocytes with abnormal size, shape, or color were expressed as a percentage. Results were compared with PCV values and zinc dose.

Results—Mean PCV value was lower in all zinc-treated ducks, compared with control ducks, and was lower in zinc-treated ducks that died or were euthanatized before day 30 because of severe clinical disease, compared with those that survived. Zinc-treated ducks that survived had a high percentage of polychromatophilic RBCs, and those that that died before day 30 had high percentages of hypochromic RBCs, fusiform RBCs, and RBC nuclear abnormalities. There was no correlation between PCV value or RBC morphologic abnormalities and dose of zinc.

Conclusions and Clinical Relevance—In ducks with severe zinc-induced hemolysis, findings indicated that functional iron deficiency may impair the effectiveness of the erythroid regenerative response and contribute to death. Erythrocyte nuclear abnormalities were consistent with mild dyserythropoiesis. These findings may be applicable to effects of other metal toxicoses and regenerative anemias in birds. (Am J Vet Res 2004;65:440–446)

Full access
in American Journal of Veterinary Research

Abstract

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.

Full access
in American Journal of Veterinary Research

Objective

To determine whether cats fed baby food with onion powder develop Heinz bodies and anemia and to establish a dose-response relation between dietary onion powder content and Heinz body formation.

Design

Prospective study.

Animals

42 healthy, adult, specific-pathogen-free cats.

Procedure

Commercial baby food with and without onion powder was fed to 2 groups of 6 cats for 5 weeks. Heinz body percentage, PCV, reticulocyte percentage, turbidity index, and methemoglobin and reduced glutathione concentrations were determined twice weekly and then weekly for 4 weeks following removal of the diet. For the dose-response study, 5 groups of 6 cats were fed a canned diet for 2 months that contained 0, 0.3, 0.75, 1.5, or 2.5% onion powder. Heinz body percentage, PCV, and reticulocyte percentage were determined twice weekly.

Results

Compared with cats fed baby food without onion powder, cats ingesting baby food with onion powder had significantly higher Heinz body percentages that peaked at 33 to 53%. Methemoglobin concentration also significantly increased but did not exceed 1.2%. Glutathione concentration, PCV, and food intake did not differ between the 2 groups. Rate and degree of Heinz body formation differed significantly between various onion powder concentrations fed. Compared with 0% onion powder, the diet with 2.5% onion powder caused a significant decrease in PCV and an increased punctate reticulocyte percentage.

Clinical Implications

Baby food or other foods containing similar amounts of onion powder should be avoided for use in cats because of Heinz body formation and the potential for development of anemia, particularly with high food intake. Cats with diseases associated with oxidative stress may develop additive hemoglobin damage when fed baby food containing onion powder. (J Am Vet Med Assoc 1998;212: 1260–1266)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine effects of lipoic acid, vitamin E, and cysteine before and after oxidant challenge in cats.

Animals—24 sexually intact adult cats.

Procedure—Cats were allocated into 4 equal groups. For 25 weeks, group A was fed a control dry diet and groups B, C, and D received this diet supplemented with vitamin E (2,200 U/kg [dry matter basis {DMB}]) plus cysteine (9.5 g/kg [DMB]), lipoate (150 mg/kg [DMB]), or all 3 antioxidants together, respectively. Weights were measured every 3 days and venous blood obtained every 5 weeks for CBC; serum biochemical analyses; lymphocyte blastogenesis; thiobarbituric acid reactive substances concentration; and concentrations of plasma protein carbonyl, 8-OH dguanosine, blood glutathione, plasma amino acid, lipoate, and dihydrolipoate. At 15 weeks, all cats received acetaminophen (9 mg/kg, PO, once), clinical effects were observed, and methemoglobin concentrations were measured.

Results—Lymphocyte blastogenesis increased transiently in group C and D cats. After acetaminophen administration, all groups had transient increases in methemoglobin within 4 hours and mild, brief facial edema; group C had decreased glutathione concentration and increased 8-OH d-guanosine concentration versus controls; and protein carbonyl concentration increased least for group B. Plasma lipoate and dihydrolipoate concentrations peaked by week 10 for groups C and D.

Conclusions and Clinical Relevance—Lipoate, vitamin E, and cysteine did not have synergistic effects. Lipoate supplementation (150 mg/kg [DMB]) did not act as an antioxidant but appeared to enhance oxidant effects of acetaminophen. Vitamin E plus cysteine had protective effects. (Am J Vet Res 2005;66:196–204)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine the effectiveness of 3 antioxidants in preventing Heinz body anemia in cats.

Design—Prospective study.

Animals—44 specific-pathogen-free healthy cats.

Procedure—Cats were housed individually, divided randomly into 4 groups, and given the following orally every 12 hours: empty gelcaps (control cats), Nacetylcysteine (NAC, 100 mg/kg of body weight), vitamin E (d,l-α-tocopherol; 400 IU), or ascorbate (250 mg). After 2 weeks, Heinz bodies were induced by dietary onion powder (OP; 1% or 3% of dry matter) or propylene glycol (PG, 8% wt/vol in drinking water) for an additional 3 weeks. Intake of treated water or food was recorded daily. Body weight, PCV, Heinz body and reticulocyte percentages, reduced glutathione concentration, and total antioxidant status were measured twice weekly in all cats.

Results—Heinz body percentage and degree of anemia did not differ significantly among cats receiving antioxidants and control cats except in cats that ingested water containing PG, in which antioxidant supplementation was associated with a decrease in water intake. Of cats that were fed a diet that contained OP, cats that received NAC had significantly higher reduced glutathione concentrations, compared with other cats in the experiment. Total antioxidant status did not consistently correlate with antioxidant supplementation or type of oxidant administered (ie, OP or PG).

Conclusions and Clinical Relevance—Although the effect of antioxidant supplementation on Heinz body anemia in cats was minimal, antioxidants may have subclinical biochemical effects such as GSH sparing that may be important against milder forms of oxidative stress. (Am J Vet Res 2001;62:370–374)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To compare sensitivity and specificity of cytologic examination and 3 chromogen tests for detection of occult blood in cockatiel (Nymphicus hollandicus) excrement.

Animals—20 adult cockatiels.

Procedures—Pooled blood from birds was divided into whole blood and lysate aliquots. Excrement was mixed with each aliquot in vitro to yield 6 hemoglobin (Hb) concentrations (range, 0.375 to 12.0 mg of Hb/g of excrement). For the in vivo portion of the study, birds were serially gavaged with each aliquot separately at 5 doses of Hb (range, 2.5 to 40 mg/kg). Three chromogen tests and cytologic examination were used to test excrement samples for occult blood. Sensitivity, specificity, and observer agreement were calculated.

Results—In vitro specificity ranged from 85%to 100% for the 3 chromogen tests and was 100% for cytologic examination. Sensitivity was 0% to 35% for cytologic examination and 100% for the 3 chromogen tests on samples containing ≥ 1.5 mg of Hb/g of excrement. In vivo specificity was 100%, 90%, 65%, and 45% for cytologic examination and the 3 chromogen tests, respectively. Sensitivity was 0% to 5% for cytologic examination and ≥ 75% for all 3 chromogen tests after birds received doses of Hb ≥ 20 mg/kg. Observer agreement was lowest for cytologic examination.

Conclusions and Clinical Relevance—Chromogen tests were more useful than cytologic examination for detection of occult blood in cockatiel excrement. The best combination of sensitivity, specificity, and observer agreement was obtained by use of a chromogen test.

Full access
in American Journal of Veterinary Research
in Journal of the American Veterinary Medical Association

Objective

To determine magnesium (Mg) status in cats with naturally acquired diabetes mellitus (DM) and diabetic ketoacidosis (DKA), evaluate changes in Mg status after treatment for DKA, and correlate Mg status with systemic blood pressure and degree of glycemic control.

Design

Case series and cohort study.

Animals

12 healthy cats (controls), 21 cats with DM, and 7 cats with DKA.

Procedure

Serum total magnesium (tMg) and ionized magnesium (iMg) concentrations and spot urinary fractional excretion of magnesium (FEmg) were determined, using serum and urine samples obtained from all cats when they were entered in the study and from cats with DKA 12, 24, and 48 hours after initiating treatment. Indirect blood pressure and degree of glycemic control were determined in 10 and 21 cats with DM, respectively.

Results

Initially, 2 and 13 cats with DM and 1 and 4 cats with DKA had serum tMg and iMg concentrations, respectively, less than the low reference limit (mean — 2 SD) determined for controls. In cats with DKA, serum tMg concentration decreased significantly over time after initiating treatment. Urinary FEmg was significantly higher in cats with DM or DKA, compared with controls. Systemic hypertension was not detected nor was there a correlation between Mg status and degree of glycemic control in cats with DM.

Conclusions and Clinical Relevance

Hypomagnesemia was a common finding in cats with DM and DKA and was more readily identified by measuring serum iMg concentration than tMg concentration. The clinical ramifications of hypomagnesemia in such cats remain to be determined. (J Am Vet Med Assoc 1999;215:1455–1459)

Free access
in Journal of the American Veterinary Medical Association