Iron Status and Erythrocyte Volume in Dogs With Congenital Portosystemic Vascular Anomalies

Microcytosis, hypochromasia, and low mean corpuscular hemoglobin are frequent hematologic abnormalities in dogs with portosystemic vascular anomalies (PSVA). The relationship of iron status to these abnormalities is unclear. We evaluated iron status and hematologic and biochemical parameters in dogs with congenital PSVA before (25 dogs) and after (11 dogs) partial ligation of the vascular anomaly. Serum iron concentration and total iron binding capacity were subnormal in 56% and 20% of dogs with PSVA, respectively. Transferrin saturation was normal in 68%, decreased in 20%, and increased in 12% of the dogs. Plasma ferritin concentration was either normal (56%) or high (44%), and was not associated with increases in ceruloplasmin concentration. Hepatic stainable iron was increased in 10 of 16 dogs. Mean corpuscular volume (MCV), mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration were decreased in more than 60% of dogs with PSVA. Serum biochemical abnormalities included high bile acid concentration and alanine transaminase (ALT) and alkaline phosphatase (ALP) activities; and low urea, creatinine, cholesterol, and total protein concentrations. Serum iron concentration and clinical status (normal or PSVA) significantly influenced MCV ( P = .003 and P < .001, respectively), whereas age, ceruloplasmin, ferritin, cholesterol, bile acids, and total iron binding capacity did not. Partial ligation of PSVA was associated with resolution of clinical signs and the return to normal of iron status and all clinicopathologic abnormalities, except total fasting bile acid concentrations. These findings indicate that iron status is frequently abnormal in dogs with PSVA and that low serum iron concentration appears to be related to the development of microcytosis. The normalization of iron status and clinicopathologic abnormalities after treatment suggests that they are direct consequences of PSVA.     

Hematologic responses in llamas with experimentally-induced iron deficiency anemia

Hematologic abnormalities consistent with iron deficiency anemia were experimentally induced in two healthy llamas by repeated phlebotomy. Hematologic abnormalities included erythrocyte microcytosis and hypochromia, decreased hemoglobin concentration, hypoferremia, and decreased transferrin saturation. Erythrocyte volume distribution histograms were more sensitive than mean corpuscular volume values for detection of microcytosis. Hypochromia, which was often eccentric, was morphologically observed on Wright-Giemsa-stained blood films. Frequent folded erythrocytes and dacryocytes were also noted on the blood films. Hematologic abnormalities resolved rapidly after cessation of blood removal, without parenteral iron supplementation.     

Hematologic features of iron deficiency anemia in llamas.

Iron deficiency anemia was identified and characterized in three 14 to 29-month-old male llamas (llama Nos. 1-3) from separate herds in Colorado. The identification of iron deficiency anemia was based on hypoferremia (serum iron = 20-60 micrograms/dl), erythrocytic features, and hematologic response to iron therapy. The anemia was moderate and nonregenerative and characterized by erythrocyte hypochromia, microcytosis (mean cell volume = 15-18 fl), and decreased mean corpuscular hemoglobin concentration (36.0-41.0 g/dl). Morphologic features unique to llamas with iron deficiency anemia included irregular distribution of hypochromia within erythrocytes and increased folded cells and dacryocytes. The cause of iron deficiency was not determined. The llamas were treated with various doses and schedules of parenteral iron dextran. Two of the llamas were monitored for up to 14 months after the start of iron therapy and experienced increases in hematocrit and mean cell volume values. In one llama, progressive replacement of microcytic cells with normal cells was visualized on sequential erythrocyte volume distribution histograms following iron therapy.     

Effect of storage on microcytosis observed in dogs with portosystemic vascular anomalies

Microcytosis is a common laboratory finding in dogs with iron deficiency and congenital portosystemic vascular anomalies (PSVA), however artefactual changes due to blood storage may occur which could mask this feature. This study evaluated the effects of storage on microcytosis in dogs with congenital PSVA. Full haematological parameters were measured on the day of sampling and following 24h storage at room temperature, in unaffected dogs (n=13) and in dogs affected with PSVA (n=24). Storage for 24h resulted in significantly higher MCV values in both groups of dogs (P<0.01). The percentage increase in MCV was greater in the control dogs (median 8.07%, range 5.64-9.31%) compared to affected dogs (median 6.05%, range 3.12-15.21%) (P<0.02). Storage of 1ml EDTA blood samples at ambient temperature for 24h prior to analysis, as occurs when samples are posted to external laboratories, will have significant effects on MCV and may mask microcytosis in dogs with PSVA.     

Customization of Advia 120 thresholds for canine erythrocyte volume and hemoglobin concentration,and effects on morphology flagging results

This study sought to develop customized morphology flagging thresholds for canine erythrocyte volume and hemoglobin concentration [Hgb] on the ADVIA 120 hematology analyzer; compare automated morphology flagging with results of microscopic blood smear evaluation; and examine effects of customized thresholds on morphology flagging results. Customized thresholds were determined using data from 52 clinically healthy dogs. Blood smear evaluation and automated morphology flagging results were correlated with mean cell volume (MCV) and cellular hemoglobin concentration mean (CHCM) in 26 dogs. Customized thresholds were applied retroactively to complete blood (cell) count (CBC) data from 5 groups of dogs, including a reference sample group, clinical cases, and animals with experimentally induced iron deficiency anemia. Automated morphology flagging correlated more highly with MCV or CHCM than did blood smear evaluation; correlation with MCV was highest using customized thresholds. Customized morphology flagging thresholds resulted in more sensitive detection of microcytosis, macrocytosis, and hypochromasia than default thresholds.     

Hematologic Changes Associated With Serum and Hepatic Iron Alterations in Dogs With Congenital Portosystemic Vascular Anomalies

Serum and hepatic iron determinations and hematologic parameters were measured in 10 dogs with congenital portosystemic vascular anomalies. Anemia, hypoferremia, and microcytosis were present in 70%, 70%, and 60% of the dogs, respectively. An increase in hepatic iron content was observed in all dogs. These results suggest a relationship between altered hepatic blood flow and abnormal iron metabolism in dogs with congenital portosystemic vascular anomalies.     

Stomatocytosis in 7 related Standard Schnauzers

BACKGROUND: Hereditary canine stomatocytosis has been described in purebred Alaskan Malamutes, Drentse Patrijshonds, and Miniature Schnauzers. In humans, hereditary stomatocytosis is a heterogeneous group of congenital disorders characterized by the presence of stomatocytes in blood, increased osmotic fragility, and frequently, hemolytic anemia. OBJECTIVE: Our objective was to describe hematologic findings and RBC characteristics in 7 closely related Standard Schnauzers with stomatocytosis. METHODS: The following parameters were measured using an automated analyzer: HCT, RBC, hemoglobin (Hb) concentration, MCV, MCH, MCHC, red cell distribution width (RDW), WBC, platelet count, mean platelet volume (MPV), thrombocrit (PCT), and platelet distribution width (PDW). Differential leukocyte count, platelet estimate, reticulocyte count, and the percentage of stomatocytes in blood films were microscopically evaluated. An osmotic fragility test of RBCs and measurement of intracellular Na+, K+, and 2,3-diphosphoglycerate (2,3-DPG) concentrations were also performed. RESULTS: The affected dogs had macrocytosis (80.0 +/- 4.2 fL, reference interval 60-76 fL), decreased MCHC (29.3 +/- 0.8 g/dL, reference interval 32-39 g/dL), slightly increased RDW (17.3 +/- 0.4%, reference interval 12-16%), and an increased reticulocyte count (1.55 +/- 0.77%, reference interval <1%). The percentage of stomatocytes in blood films varied from 0.6 to 18.9% of all RBCs. Erythrocyte osmotic fragility and intracellular Na+ (138.1 +/- 3.2 mmol/L; controls 99 +/- 6.1 mmol/L), K+ (8.1 +/- 0.8 mmol/L; controls 6.1 +/- 0.5 mmol/L), and 2,3-DPG (21.9 +/- 2.0 micromol/g Hb; controls: 14.6 +/- 3.3 micromol/g Hb) concentrations were increased in dogs with stomatocytosis. CONCLUSIONS: Hematologic findings and the metabolic defects in RBCs in these Standard Schnauzers were consistent with a diagnosis of stomatocytosis. Parentage analysis suggests that stomatocytosis in Standard Schnauzers may have a hereditary component.     

Hematologic and biochemical abnormalities indicating iron deficiency are associated with decreased reticulocyte hemoglobin content (CHr) and reticulocyte volume (rMCV) in dogs

BACKGROUND: The ADVIA 120 automated hematology system uses low- and high-angle light scatter to determine individual RBC and reticulocyte volume and hemoglobin (Hgb) concentration. Current hematologic and biochemical markers of iron status in the dog are insensitive, and results may be highly variable, especially in the presence of concurrent disease (ie, inflammation, neoplasia). Reticulocyte Hgb content (CHr) has proven useful in detecting early iron deficiency and iron deficiency masked by concurrent disease in human patients. OBJECTIVES: The purpose of this study was to retrospectively investigate the association of low CHr and reticulocyte MCV (rMCV) with hematologic and biochemical abnormalities indicative of iron deficiency in canine patients. METHODS: Reference intervals for CHr and rMCV were established on a population of 362 hematologically-normal dogs using standard methods. CBC and serum biochemical results from 833 dogs at Colorado State University Veterinary Teaching Hospital were retrospectively evaluated. The prevalence of decreased CHr and rMCV values was determined based on the reference intervals. Hematologic (HCT, MCV) and biochemical (serum Fe concentration, percent saturation of transferrin [% sat]) values were compared among dogs with low CHr (n=58), low rMCV (n=50), and control dogs (cohort groups from the initial population) using a Fisher exact test. RESULTS: Reference intervals were 22.3-27.9 pg for CHr and 77.8-100.2 fL for rMCV. Seven percent (n=58) of dogs in the hospital population had low CHr and 6% (n=50) had low rMCV based on the reference values. Dogs with low CHr had significantly lower HCT, MCV, serum Fe, and % sat values than did control dogs. In addition, dogs with low CHr or low rMCV values had a higher frequency of microcytosis, anemia, low serum Fe concentration, and low % sat than did control dogs. CONCLUSION: Low CHr and low rMCV are associated with hematologic and serum biochemical abnormalities indicative of iron deficiency. CHr and rMCV hold promise as noninvasive, cost-effective measures of iron status in the dog.     

Effect of repeated phlebotomy on iron status of rhesus monkeys (Macaca mulatta).

Iron status, as determined by hematologic values, serum iron concentration, total iron-binding capacity, and zinc protoporphyrin concentration, was determined in 2 groups of 6 nonpregnant monkeys. Monkeys of groups 1 and 2 had 10 and 5%, respectively, of their blood volume withdrawn per week for up to 10 weeks or until blood hemoglobin concentration was less than or equal to 10 g/dl. A third group of 6 monkeys served as controls. The majority (8/12) of the monkeys became anemic (hemoglobin concentration, less than or equal to 10 g/dl) after approximately 30 to 70% (mean, 49%) of their blood volume was removed. Anemia was accompanied by decrease in serum iron concentration and percentage of transferrin saturation. Microcytosis, hypochromasia, and increased zinc protoporphyrin concentration, all hematologic characteristics of iron deficiency, developed later. The calculated iron stores ranged from 1 to 133 mg, with mean value of 51 mg. Iron-depleted monkeys had mean calculated available iron store of 20.8 mg, whereas iron-replete monkeys had mean available iron store of 114.0 mg. Changes were not observed in monkeys of the control group during the study period. None of the baseline hematologic or biochemical analytes measured were good predictors of iron stores. The diet used at the research center did not provide sufficient iron to prevent iron deficiency in most of the monkeys from which a total amount of 30 to 70% of blood volume at 5 or 10%/week was withdrawn. Studies requiring that much blood may need to be modified to include iron supplementation, reduction of sample volume, or iron replacement after termination of projects.     

Effect of dietary iron content on hematologic and other measures of iron adequacy in dogs

Eighteen 9- to 10-week old Beagles were fed casein-based diets (4,710 kcal of metabolizable energy/kg of body weight) containing either 12, 80, or 160 mg of iron/kg of diet. Growth and feed consumption were monitored throughout the 47-day study. Hematocrit (Hct), hemoglobin (Hb) concentration, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), RBC numbers, erythrocyte protoporphyrin (EP) concentration, serum iron concentration, serum total iron-binding capacity (TIBC), and serum ferritin concentration were determined weekly. Growth rate and feed efficiency were not significantly influenced by dietary iron content. At 14 days, Hb concentration, Hct, MCV, MCH, RBC numbers, and serum iron concentration were significantly (P less than 0.05) lower in dogs fed the 12 mg/kg diet, and remained significantly low for the remainder of the study. Erythrocyte protoporphyrin concentration increased significantly (P less than 0.05) by 14 days in dogs fed the basal diet, and remained significantly high relative to that in dogs of the other dietary groups for the remainder of the study. Serum ferritin concentration decreased in dogs of the group fed the basal diet, with a significant (P less than 0.05) difference beyond day 42. Differences in Hct, MCH, MCV, or hemoglobin, serum iron, serum ferritin, or EP concentration were not found between groups fed 80 and 160 mg of iron/kg of diet. Liver nonheme iron content was significantly (P less than 0.05) affected by dietary iron content.     

Evaluation of Iron Deficiency Using Reticulocyte Indices in Dogs Enrolled in a Blood Donor Program

Background

People donating blood more than twice annually are at risk of developing iron deficiency. Little is known about the iron status of dogs enrolled in blood donor programs.

Hypothesis

Dogs donating blood ≥6 times annually will show evidence of iron deficiency based on their reticulocyte indices.

Animals

Thirteen dogs enrolled in a blood donor program donating ≥6 times over the preceding 12 months and 20 healthy nondonor control dogs.

Methods

Prospective observational study. Mature red blood cell (RBC) indices, reticulocyte indices, serum iron, serum ferritin, and total iron‐binding capacity (TIBC) were compared between groups.

Results

Packed cell volume (median 47%, range 40–52%, P < .01), hematocrit (median 46.4%, range 40.3–52.5%, P < .01), and reticulocyte count (median 16,000/μL, range 9,000–38,000/μL, P < .01) were significantly lower in the blood donor dogs. No statistically significant differences were noted in the mature RBC indices between groups. Both reticulocyte mean corpuscular volume (median 88.8 fL, range 83.4–95.5 fL, P = .03) and reticulocyte hemoglobin content (median 24.6 pg, range 23.1–26.6 pg, P < .01) were significantly lower in the blood donor group. Serum iron and ferritin were similar between groups; however, TIBC was significantly higher in the control group (median 403 μg/dL, range 225–493 μg/dL, P = .02).

Conclusions

The findings in dogs donating ≥6 times annually suggest the presence of iron‐deficient erythropoiesis in this population.     

Characterization of erythrocytic indices and serum iron values in healthy llamas.

An electronic particle counter with attached particle-size analyzer was configured to directly determine concentration, mean cell volume, and volume distribution of erythrocytes in llama blood. Blood from 38 healthy llamas was used to characterize erythrocytic measurements and serum iron values for this species. Volume distribution curves for llama erythrocytes were similar in shape to those of other species. These curves had a unimodal, symmetric shape with a tail skewed to the right. Reference ranges for directly measured mean cell volume, erythrocyte concentration, hemoglobin concentration, and mean cell hemoglobin concentration were 21 to 28 fl, 11.3 x to 17.5 x 10(6) cells/microliters, 12.8 to 17.6 g/dl, and 43.2 to 46.6 g/dl, respectively. Reference ranges for serum iron concentration, total iron-binding capacity, and transferrin saturation were determined to be 70 to 148 micrograms/dl, 230 to 370 micrograms/dl, and 22 to 50%, respectively.     

Macrocytosis secondary to hydroxyurea therapy

A 10‐year‐old, male neutered Shetland Sheepdog was presented to the University of Florida for evaluation of a well‐granulated mast cell tumor. Hydroxyurea therapy was instituted and serial CBCs showed persistent mild anemia and macrocytosis without a corresponding increase in polychromasia. The dog's MCV increased progressively, reaching its highest value of 100.0 fL after 6 months of treatment, and a diagnosis of macrocytosis associated with hydroxyurea therapy was made. The dog's increase in MCV was prominent, and rapidly decreased after the drug was discontinued, consistent with previous observations in human and canine subjects treated with hydroxyurea. Hydroxyurea is a cytotoxic chemotherapeutic agent used in a variety of conditions in human and veterinary medicine, and megaloblastic changes associated with its use have been described in multiple species. This report shows that hydroxyurea treatment is a differential diagnosis for prominent macrocytosis in dogs in the absence of other signs of erythrocyte regeneration.     

USE OF MAGNETIC RESONANCE ANGIOGRAPHY FOR DIAGNOSIS OF PORTOSYSTEMIC SHUNTS IN DOGS

A prospective study was conducted to determine the sensitivity and specificity of diagnosis of portosystemic shunts (PSS) and the accuracy of anatomically locating single congenital PSS in dogs using magnetic resonance angiography (MRA). MRA was performed on 10 normal dogs and 23 dogs with PSS. Sensitivity and specificity of MRA to diagnose any shunt among all dogs were 80% and 100%, respectively. Among dogs identified with PSS, sensitivity and specificity of MRA for diagnosis of multiple extrahepatic shunts were 63% and 97%, respectively, and for diagnosis of single congenital shunts were 79% and 100%, respectively. Using MRA, radiologists correctly identified shunts as extrahepatic or intrahepatic in 83% of patients and correctly identified the origin and insertion of the shunts in 57% and 97% of patients, respectively. Use of MRA is specific for diagnosis of PSS and is a sensitive indicator of anatomic location of single congenital portosystemic shunts.     

Experimental onion-induced hemolytic anemia in dogs

Within one day following a single oral dose of dehydrated onions, dogs were found to have large numbers of Heinz bodies within erythrocytes. The percentage of erythrocytes that contained Heinz bodies increased slightly to a maximum on day 3 and then declined. The turbidity index increased more gradually with a maximal value on day 4. Erythrocytes with hemoglobin contracted to one side of the cell (eccentrocytes) also appeared after onion feeding. Eccentrocytes are believed to result from a direct injury to the erythrocyte membrane. As with Heinz body-containing cells, the percentages of eccentrocytes present declined as anemia developed. The packed cell volume began to decrease one day after onion administration. A mean decrease of 19 percentage points was reached by day 5. The most anemic dogs had evidence of intravascular hemolysis. Reticulocytosis was first observed five days after onion administration. A slight increase in methemoglobin content was measured four hours after onion administration. No significant changes in erythrocyte reduced glutathione concentration were measured. Transient neutrophilia occurred concomitant with the peak reticulocyte response.     

Susceptibility to onion-induced hemolysis in dogs with hereditary high erythrocyte reduced glutathione and potassium concentrations.

The hemolytic effect of onion consumption in dogs with hereditary high erythrocyte reduced glutathione and potassium concentrations (designated HK dogs) was compared with that in clinically normal dogs. Twelve hours after oral administration of boiled onions (200 g/dog), hemoglobin concentration decreased to 84.4% of the initial value in HK dogs; it decreased only to 90.5% in clinically normal dogs. At 24 hours, methemoglobin concentration was significantly (P less than 0.05) higher in HK dogs than in clinically normal dogs. The concentration of erythrocyte oxidized glutathione increased about fivefold at 10 hours in HK dogs, whereas it did not change during the experimental period in clinically normal dogs. In addition, at 12 hours, the proportion of erythrocytes containing Heinz bodies increased to 24.4% in HK dogs, but increased only to 1.2% in clinically normal dogs. Thus, results indicated that HK dogs were more susceptible to the oxidant action of onions than were clinically normal dogs.     

3种雉科鸟类血液生理指标的比较研究

为了解勺鸡、雉鸡和石鸡血液生理参数的正常值及其特点,为人工饲养繁殖以及健康状况监测提供参考依据,采用常规方法,对人工饲养的3种雉科鸟类(勺鸡、雉鸡和石鸡)红细胞数、白细胞总数、白细胞分类计数、血小板数、血红蛋白含量、红细胞沉降率、红细胞体积及红细胞比容8项血液生理指标进行了测定。结果表明,雉鸡的血小板明显高于勺鸡和石鸡(P<0.05);其它7项血液生理指标3种鸟之间差异不显著(P>0.05)。     

Leptin gene haplotypes are associated with change in immunological and hematological variables in dairy cow during the peripartum period

In this study, the effect of polymorphisms in the leptin gene on the hematological variables in periparturient dairy cows was investigated. The hematological profile of 67 Holstein cows was assessed for 6 wk around calving. The DNA of the cows was genotyped at 6 polymorphic loci within the leptin gene, and 7 haplotypes were reconstructed. Significant haplotype substitution effects were found, for haplotype 1, on total white blood cell count for 2 wk around calving (+0.70 10(3)/μL, P = 0.05; +1.38 10(3)/μL, P = 0.0001); on neutrophil cell count in the first week after calving (+0.94 10(3)/μL, P = 0.001); on lymphocyte count during the 3 wk before and the first week after calving (+0.32 10(3)/μL, P = 0.05; +0.27 10(3)/μL, P = 0.03; +0.26 10(3)/μL, P = 0.04; +0.34 10(3)/μL, P = 0.01); on red blood cell count during the last week before calving and wk 1 and 2 after calving (+0.21 10(6)/μL, P = 0.02; +0.23 10(6)/μL, P = 0.01; +0.20 10(6)/μL, P = 0.03); on mean corpuscular volume (-1.35 fL, P = 0.01; -1.29 fL, P = 0.002; -1.18 fL, P = 0.004; -1.09 fL, P = 0.008; -1.23 fL, P = 0.003; -1.31 fL, P = 0.003); and on mean corpuscular hemoglobin (-0.37 pg, P = 0.05; -0.38 pg, P = 0.02; -0.39 pg, P = 0.01; -0.34 pg, P = 0.03; -0.40 pg, P = 0.01; -0.40 pg, P = 0.01) during all 6 wk analyzed. Significant haplotype substitution effects, but opposite those of haplotype-1, were found for haplotype-2 on white blood cell count (-1.10 10(3)/μL, P = 0.01; -1.30 10(3)/μL, P = 0.002; -1.09 10(3)/μL, P = 0.01) and neutrophil count (-0.82 10(3)/μL, P = 0.02; -0.95 10(3)/μL, P = 0.005; -0.92 10(3)/μL, P = 0.01). Haplotype-3 influenced red blood cell count (-0.23 10(6)/μL, P = 0.03; -0.28 10(6)/μL, P = 0.01; -0.34 10(6)/μL, P = 0.002) during the last 2 wk before and the first week after calving, and also, with effects evident only in wk 3 and 2 before calving, mean corpuscular volume (+1.38 fL, P = 0.03; +0.97 fL, P = 0.05; +1.08 fL, P = 0.05), mean corpuscular hemoglobin (+0.58 pg, P = 0.02; +0.38 pg, P = 0.04; 0.51 pg, P = 0.01), and red blood cell distribution width (-0.56% P = 0.02; -0.47%, P = 0.05). The current study provided evidence that several polymorphisms in the leptin gene play a role in the variability of hematological variables during the peripartum period, and might be used as genetic markers for improving the immunological conditions of dairy cows in critical productive periods.     

Effect of immune-mediated erythrocyte agglutination on analysis of canine blood using a multichannel blood cell counting system

Blood from six dogs with in vitro immune-mediated erythrocyte agglutination resulted in analytical errors in directly measured counting and sizing functions on a multichannel blood analysis system with histogram capability. Errors in the directly measured values, mean cell volume (MCV), and erythrocyte count were attributed to agglutinated erythrocyte particles that persisted during the relatively short reagent contact time of the analysis. Agglutinated particles less than 240 fl were visible on erythrocyte histograms and resulted in a false low erythrocyte count and false high MCV. Agglutinated cell particles greater than 240 fl were not present on the histogram scale. Because these latter particles exceeded the upper threshold, they did not influence determination of MCV, but resulted in a further decrease in the erythrocyte count. As a result, the other dependent erythrocyte indices were in error. These included false low hematocrit and false high mean corpuscular hemoglobin concentration (MCHC), when compared to corrected reference blood values. Similar errors occurred when analyzing blood samples that were agglutinated in vitro by incubating erythrocytes with incompatible plasma. The counting and sizing errors observed with electronic counting techniques were eliminated or greatly reduced by incubating blood in cell counting diluent for 10 minutes followed by analysis on a single channel counter with attached particle size analyzer. Error in erythrocyte measurement on a multichannel system may be anticipated if there is overt erythrocyte agglutination in a blood sample, an abnormally high MCHC is reported by the system, or subpopulations of large volume (agglutinated cells) are observed on a volume distribution histogram.