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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.

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in Journal of the American Veterinary Medical Association

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
in Journal of the American Veterinary Medical Association

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

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

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 identify geographic areas in the United States where food animal veterinary services may be insufficient to meet increased needs associated with the US FDA's Veterinary Feed Directive.

DESIGN Cross-sectional study.

SAMPLE Data collected between 2010 and 2016 from the US Veterinary Medicine Loan Repayment Program, the National Animal Health Monitoring System Small-Scale US Livestock Operations Study, and the USDA's National Veterinary Accreditation Program.

PROCEDURES Each dataset was analyzed separately to identify geographic areas with greatest potential for veterinary shortages. Geographic information systems methods were used to identify co-occurrence among the datasets of counties with veterinary shortages.

RESULTS Analysis of the loan repayment program, Small-Scale Livestock Operations Study, and veterinary accreditation datasets revealed veterinary shortages in 314, 346, and 117 counties, respectively. Of the 3,140 counties in the United States during the study period, 728 (23.2%) counties were identified as veterinary shortage areas in at least 1 dataset. Specifically, 680 counties were identified as shortage areas in 1 dataset, 47 as shortage areas in 2 datasets, and 1 Arizona county as a shortage area in all 3 datasets. Arizona, Kentucky, Missouri, South Dakota, and Virginia had ≥ 3 counties identified as shortage areas in ≥ 2 datasets.

CONCLUSIONS AND CLINICAL RELEVANCE Many geographic areas were identified across the United States where food animal veterinary services may be inadequate to implement the Veterinary Feed Directive and meet other producer needs. This information can be used to assess the impact of federal regulations and programs and help understand the factors that influence access to food animal veterinary services in specific geographic areas.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To compare results of thoracic radiography, cytologic evaluation of bronchoalveolar lavage (BAL) fluid, and histologic evaluation of biopsy and necropsy specimens in dogs with respiratory tract disease and to determine whether histologic evaluation provides important diagnostic information not attainable by the other methods.

Design—Retrospective study.

Animals—16 dogs.

Procedure—BAL fluid was classified as normal, neutrophilic, eosinophilic, mononuclear, mixed, neoplastic, or nondiagnostic. Radiographic abnormalities were classified as interstitial, bronchial, bronchointerstitial, or alveolar. Histologic lesions were classified as inflammatory, fibrotic, or neoplastic, and the predominant site of histologic lesions was classified as the alveoli, interstitium, or airway.

Results—The predominant radiographic location of lesions correlated with the histologic location in 8 dogs. Of 11 dogs with histologic evidence of inflammatory disease, 8 had inflammatory BAL fluid. Of the 2 dogs with histologic evidence of neoplasia, 1 had BAL fluid suggestive of neoplasia, and the other had BAL fluid consistent with septic purulent inflammation. Two dogs without any histologic abnormalities had mononuclear or nondiagnostic BAL fluid. Two dogs with histologic evidence of fibrosis had mononuclear or mixed inflammatory BAL fluid.

Conclusions and Clinical Relevance—Results suggest that although thoracic radiography, cytologic evaluation of BAL fluid, and histologic evaluation of lung specimens are complementary, each method has limitations in regard to how well results reflect the underlying disease process in dogs with respiratory tract disease. Lung biopsy should be considered in cases where results of radiography and cytology are nondiagnostic. (J Am Vet Med Assoc 2001;218: 1456–1461)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the extent of use of cytology as a diagnostic method in veterinary practice and assess how veterinarians in practice communicate with veterinary clinical pathologists.

Design—Online survey.

Study Population—870 veterinarians.

Procedures—An online survey was made available to members of the Veterinary Information Network from October 1, 2004, through December 1, 2004.

Results—Respondents reported obtaining a median of 7 cytology samples weekly (range, 0 to 100). On average, respondents reported that 48.1% of the samples they collected were evaluated in-house, 29.5% were submitted to a veterinary diagnostic laboratory, and 21.6% were evaluated in-house and then submitted to a diagnostic laboratory. Most respondents (89.2%) reported using cytologic assessments to guide additional testing, and most (80.3%) indicated that they found the comments section of the cytology report to be the most important section. When asked to indicate the importance of various factors in their decision to use cytology as a diagnostic method, respondents overwhelmingly indicated that accuracy was very important. The most common reasons for consulting with a clinical pathologist were to discuss a discrepancy between clinical and cytologic findings, to clarify a diagnosis, and to ascertain the pathologist's confidence in a diagnosis. Respondents expressed more confidence in results when board-certified clinical pathologists were examining cytology samples than when others were.

Conclusions and Clinical Relevance—Results suggested that improving communication between veterinary practitioners and veterinary clinical pathologists could enhance the diagnostic value of cytologic examinations and improve clinical decision-making.

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in Journal of the American Veterinary Medical Association