Evaluation of a hematology analyzer with canine and feline blood

A semiautomatic electronic blood cell counter (Sysmex F-800:Toa Medical Electronics Europa Gmbh, Hamburg, Germany) was evaluated using canine and feline blood, following the International Committee for Standardization in Hematology protocol (ICSH, 1984). Precision and overall reproducibility were acceptable for all the parameters studied except for the feline platelet count, in which overlapping of erythrocyte and platelet populations prohibited determination of an accurate platelet count. Since carry-over from canine hematocrit values and platelet counts and from feline hematocrit values was unsatisfactory, the use of a blank diluent sample between different analyses was necessary. Linearity of the analyzer was acceptable in the studied range. Thirty canine and feline blood samples were analyzed using the Sysmex F-800 and a manual method. Correlations between both methods were acceptable for all the parameters, except for feline platelet count and erythrocyte indices for both species. In the storage study, red blood cell count and hemoglobin concentration were the parameters with the longest stability (72 hours at 4 degrees C and 25 degrees C) in both species. A statistically significant increase in MCV was obtained at 12 hours post-extraction in canine samples stored at 25 degrees C and at 24 hours in refrigerated samples. Feline leucocyte counts showed a downward trend at 12 hours post-extraction at both temperatures. Canine platelet count decreased significantly at 6 hours post-extraction in samples stored at 4 degrees C. During the evaluation period, Sysmex F-800 was user friendly and appeared well suited for routine canine and feline blood cell analysis.     

Changes in platelet concentrates from dogs due to storage. I. Platelet count in in vitro function]

The possibility of storage of canine platelet concentrates (PC) was investigated using PC from dogs which were obtained with an automatic cell separator in C4-cell separation sets with low gasdiffusionable Polyvinylchlorid (PVC) storage containers or in C4L-sets developed for storage with high gasdiffusionable Polyolefin (PO) containers, respectively. The storage was carried out for a period of 10 days under permanent agitation at 22 degrees C (C4/22 degrees C, n = 10; C4L/22 degrees C, n = 11) or at 4 degrees C (C4L/4 degrees C, n = 6), respectively. Measurements were done directly after production of the PC, after 6 hours and then daily during the 10-day storage period. In the first part of this paper the results of platelet count (determined automatically with a blood cell differentiation automat and visually), the number of platelet aggregates, the mean platelet volume (MPV) as well as the platelet function with regard to the platelet aggregation induced by collagen or ADP and the resonance-thrombogram (RTG) are presented. The platelet count, measured automatically as well as visually, remained preponderantly constant over the complete storage time in all storage conditions. Dependent on the storage conditions--especially under storage at 22 degrees C--an increase of the number of platelet aggregates and a decrease of MPV was determined. In addition, the loss of platelet function measured by aggregation induced by collagen as well as by ADP showed a significant dependency of storage conditions. The stored platelets lost their ability to aggregate under C4/22 degrees C-conditions after a storage period of 2 days, under C4L/22 degrees C-conditions after 4 days and under C4L/4 degrees C-conditions not before 8 days of storage. Previous resuspending of platelets in fresh plasma delayed the loss of platelet function. Because the loss of platelet function described in the RTG became significant at nearly the same point in time, a storage of canine PC under corresponding conditions can be recommended for upto 2 days (C4/22 degrees C), for 4 days (C4L/22 degrees C) or 8-10 days (C4L/4 degrees C), respectively.     

Whole body hyperthermia: effects upon canine immune and hemostatic functions.

In this study, the effects of induced whole body hyperthermia (WBH; 42.3 degrees C for 90 min) on peripheral blood mononuclear cell (PBMC) phenotype distribution, in vitro blastogenic responsiveness and selected parameters of hemostasis were determined in dogs. Hyperthermia was induced by heating venous blood during extracorporeal circulation (EC); induction of WBH by peritoneal lavage (PL) and perfusion without heating (i.e. euthermic EC and euthermic PL) were used as controls. Whole body hyperthermia was associated with lymphopenia and thrombocytopenia that persisted throughout the eight-day post-treatment observation interval. The lymphopenia was selective in that CD5-positive T lymphocytes were more sensitive than were sIg-positive B cells and, within the T-cell compartment, suppressor (CD8-positive) cells were more sensitive to hyperthermic stress than helper (CD4 positive) lymphocytes. Lymphopenia was also observed in EC and PL euthermic controls, although that lymphopenia was transient and nonselective. Persistent suppression of T-cell phytomitogen-induced blastogenesis was induced by WBH in contrast to transient suppression in euthermic controls. For all treatment groups, lymphopenia and suppressed blastogenesis were correlated to elevated plasma cortisol levels. Induction of WBH by EC resulted in coagulopathy characterized by thrombocytopenia, increased plasma fibrin degradation products, prolonged clotting times, and evidence of spontaneous bleeding. These hemostatic alterations were correlated temporally to increased serum levels of liver enzymes. However, there was no evidence of hepatic injury when WBH was induced by PL, where transient thrombocytopenia was the only significant hemostatic alteration. These results indicate that 42.3 degrees C whole body hyperthermia can be well-tolerated and, although associated with suppression of general indexes of immunocompetence, is not associated with opportunistic infections.     

Evaluation of equine hemograms using the ADVIA 120 as compared with an impedance counter and manual differential count

BACKGROUND: The ADVIA 120 is an automated laser cell counter widely used in veterinary medicine. Although specific software for equine samples is available and validated, only a few reports have been published comparing the ADVIA 120 with other methods for equine hemogram evaluation. OBJECTIVES: The purpose of this study was to compare the hematologic values and reference intervals obtained on the ADVIA 120 with those obtained on an impedance cell counter and manual differential counts in healthy horses. METHODS: EDTA-anticoagulated blood samples were obtained from 114 clinically healthy horses of various breeds, both sexes, and 2-6 years of age. Samples were stored for up to 12 hours at 4 degrees C and then analyzed on the ADVIA 120 and the Hemat 8. A 100-cell to 200-cell differential leukocyte count was performed by 3 independent observers on May-Grünwald-Giemsa-stained smears. Intra-assay precision of the ADVIA 120 was determined by analyzing 5 replicates each of 10 of the blood samples. RESULTS: Results from the ADVIA were significantly higher than those from the impedance counter for RBC count, total WBC count, hemoglobin concentration, red cell distribution width, MCH, and MCHC, and significantly lower for HCT and platelet count. Significantly higher neutrophil and basophil counts and significantly lower lymphocyte counts were obtained with the ADVIA 120 compared with manual counts. Based on Passing-Bablok regression analysis, RBC and platelet counts were in good agreement between the 2 analyzers; a constant and proportional bias was present for other values. Coefficients of variation for erythrocyte parameters on the ADVIA were <1%, but were higher for platelet (6%), total WBC (2%), differential WBC (4%-30%), and reticulocyte (75%) counts. CONCLUSIONS: Results obtained with equine samples on the ADVIA 120 were comparable with those obtained on an impedance counter; reference intervals differed statistically but overlapped. The ADVIA had poor precision for reticulocyte and differential leukocyte counts such that the latter should always be verified on smears.     

Artifactual changes in canine blood following storage, detected using the ADVIA 120 hematology analyzer

BACKGROUND: Artifactual changes in blood may occur as a consequence of delayed analysis and may complicate interpretation of CBC data. OBJECTIVE: The aim of this study was to characterize artifactual changes in canine blood, due to storage, using the ADVIA 120 hematology analyzer. METHODS: Blood samples were collected into EDTA from 5 clinically healthy dogs. Within 1 hour after blood sample collection and at 12, 24, 36 and 48 hours after storage of the samples at either 4 degrees C or room temperature (approximately 24 degrees C), a CBC was done using the ADVIA 120 and multispecies software. A linear mixed model was used to statistically evaluate significant differences in values over time, compared with initial values. RESULTS: The HCT and MCV were increased significantly after 12 hours of collection at both 4 degrees C and 24 degrees C, and continued to increase through 48 hours. The MCHC initially decreased significantly at 12-24 hours and then continued to decrease through 48 hours at both temperatures. Changes in HCT, MCV, and MCHC were greater at 24 degrees C than at 4 degrees C at all time points. A significant increase in MPV and a decrease in mean platelet component concentration were observed at all time points at 24 degrees C. Samples stored at 24 degrees C for 48 hours had significantly higher percentages of normocytic-hypochromic RBCs, and macrocytic-normochromic RBCs, and lower platelet and total WBC counts. CONCLUSIONS: Delayed analysis of canine blood samples produces artifactual changes in CBC results, mainly in RBC morphology and platelet parameters, that are readily detected using the ADVIA 120. Refrigeration of specimens, even after 24 hours of storage at room temperature, is recommended to improve the accuracy of CBC results for canine blood samples.     

Changes in platelet concentrates from dogs due to storage. II. Biochemical changes in concentrate plasma]

Platelet concentrate (PC) obtained from dogs with an automatic cell separator was stored in C4-cell separation sets with low gasdiffusionable Polyvinylchlorid (PVC) storage containers or in C4L-sets developed for storage with high gasdiffusionable Polyolefin(PO) containers, respectively. PC were stored for 10 days under permanent agitation at 22 degrees C (C4/22 degrees C, n = 10; C4L/22 degrees C, n = 11) or at 4 degrees C (C4L/4 degrees C, n = 6), respectively. Measurements were carried out directly after production of the PC, after 6 hours and then daily during the 10-day storage period. In the second part of this paper the results of pH, the concentration of bicarbonate, glucose, lactate and potassium ions as well as the activity of lactate dehydrogenase (LDH) are presented. The varying duration and intensity of the energy metabolism of the platelets and different part of glycolysis became obvious by the consumption of glucose and production of lactate, which differed significantly between the different storage conditions. Resulting from this, the mean pH decreased under the limit prescribed for human PC (pH = 6.3) already after a storage period of 3 days due to the slight capacity of gas diffusion in PVC-containers (C4/22 degrees C). In the PO-containers the pH fell below this limit at 22 degrees C (C4L/22 degrees C) after a storage period of 5 days and at 4 degrees C (C4L/4 degrees C) after 10 days. The latter reflects the high gas diffusion capacity of the PO-containers and the decreased metabolism activity at 4 degrees C. The increase of activity of LDH and of the concentration of potassium ions, which are localized in the cytosol of platelets, depended also on the different storage conditions and, thereby, reflected the different rapidity of increasing membrane permeability or the destruction of the cell membrane, respectively. The results of this study nearly are in agreement with the changes of platelet function shown in part I. Biochemical changes occur in canine platelet concentrates similar to those in human platelet concentrates during storage in dependency of the storage conditions, in part even with a higher rate or in a higher extent.     

Effects of Increased Ambient Temperature During IVM and/or IVF on the In Vitro Development of Bovine Zygotes

Previous research by this group (2003) has demonstrated that heat stress during in vitro culture (IVC) significantly increased early embryo mortality. The experiments reported here examine the effects of heat treatment (HT) during in vitro maturation (IVM) and during in vitro fertilization (IVF). One 24 h cycle of HT entailed a series of 0.5 degrees C incubator temperature increases from 39 degrees C to 39.5 degrees C for 2 h, to 40 degrees C for 2 h, to 40.5 degrees C for 4 h, 41 degrees C for 4 h, 40.5 degrees C for 6 h and 40 degrees C for 6 h. This cycle mimics rectal temperatures recorded in high producing, grain fed dairy cows in hot climates. Experiment I studied the effects of one cycle of heat-treatment during IVF on the rate of cleavage of in vitro matured presumptive zygotes. Total cleavage rate in the HT group (37.8%) was lower than that of the control group (54.6%, p < 0.05). Experiment II repeated the HT of experiment I but preceded it with a cycle of HT during IVM. The total cleavage rates for control and heat treatment groups were 75.5% and 37.9%, respectively, with a significant difference of p < 0.001 identified. Experiment III examined the rates of embryonic development to >or=8-cell stage (after 72 h IVC) and to morula or blastocyst (M/B) stage (after 144 h IVC) following HT of the oocyte groups during the preceding IVM or IVF. Rates of development to >or=8-cell stage (at 72 h IVC) and to M/B stage (after 144 h IVC) for the control group were 27.5% and 35.8%. Those of IVM-only HT and IVF-only HT groups were 13.8% and 14.6%, and 8.6% and 14.3%, respectively. Both groups of heat treated embryos developed at significantly lower rates (p < 0.05) than did the control group. These results suggest that hyperthermia during oocyte maturation and/or fertilization adversely affects oocyte maturation and fertilization rates and retards further embryonic development.     

Freezing of sheep faeces invalidates Haemonchus contortus faecal egg counts by the McMaster technique

Faecal pellets from a sheep that was artificially infected with a monoculture of Haemonchus contortus were collected over a 2-h period in the morning. In the laboratory the faeces were thoroughly mixed by hand and 48 by 1 g aliquots of the pellets were sealed in plastic bags, from which the air had gently been expressed. The faecal worm egg count of the sheep was about 14,000 g(-1). Varying numbers of the bags were either processed for faecal worm egg counting (FEC) by the McMaster technique on day 0, or were stored at one of the following temperatures: about 4 degrees C, -10 degrees C or -170 degrees C before processing. The faecal aliquots that were frozen were thawed at room temperature after having been frozen for either 2 h or 7 days, and processing of aliquots maintained at 4 degrees C proceeded shortly after the samples had been removed from the refrigerator. A dramatic reduction in egg numbers was found in all the aliquots that were frozen at -170 degrees C before faecal worm egg counts were done, as well as in those frozen for 7 days at about -10 degrees C. Numerous empty, or partially empty, egg shells were observed when performing the counts in faeces that had been frozen. In contrast, there was no significant reduction in the numbers of eggs in aliquots maintained for 7 days in a refrigerator at +/- 4 degrees C before examination, when compared with others examined shortly after collection of the faeces. Since H. contortus eggs in faeces are damaged by freezing, some methods that can be used for short term preservation are outlined. It is concluded that all nematode egg counts from cryopreserved faeces (whether in a freezer at -10 degrees C or in liquid nitrogen) should possibly be regarded as being inaccurate, unless the contrary can be demonstrated for different worm genera. However, exceptions are expected for the more rugged ova, such as those of the ascarids and Trichuris spp.     

Evaluation of a citrate-based anticoagulant with platelet inhibitory activity for feline blood cell Counts

Abstract: Aggregation of feline platelets in vitro results in difficulty assessing platelet number. A citrate-based anticoagulant containing the platelet inhibitors theophylline, adenosine, and dipyridamole (CTAD; Diatube-H, Becton Dickinson, Oxford, UK) has been developed for use in human platelet studies and heparin assays. To evaluate the efficacy of CTAD in reducing platelet aggregation in feline blood samples, aliquots of blood from 51 cats were anticoagulated with EDTA, CTAD, and for 12 samples, citrate solution. Samples preserved in CTAD had significantly higher (P ≤ .001) platelet counts, as determined by an impedance counter, hemacy-tometer, and smear estimation, than samples preserved in EDTA. In addition, subjective assessment of blood smears showed significantly fewer platelet aggregates (P<.001) in CTAD-treated samples compared with EDTA samples. Although values were similar, automated platelet counts and smear estimates of platelet number were significantly higher (P < .05) and platelet aggregation was significantly less (P < .05) in CTAD samples than in citrate samples. These results suggest that the platelet inhibitory activity of CTAD reduced feline platelet aggregation. Automated total WBC counts in CTAD samples were significantly lower (P<.001) than automated counts in EDTA samples but were similar to manual WBC counts in EDTA samples. Differences in both platelet and WBC counts between CTAD and EDTA or citrate samples were clinically relevant. Mean platelet volume and MCV were significantly lower (P< .05) in CTAD samples than in EDTA samples. No effect was seen on cell morphology or staining characteristics. The anticoagulant CTAD offers an advantage over both EDTA and citrate for feline hematologic analysis, by decreasing pseudothrombocytopenia and pseudoleukocytosis.     

Determination of the number of somatic cells in milk using the rapid diphenylamine DNA filter method

The rapid reaction of the diphenylamine agent with DNA was used for the determination of the counts of somatic cells in cow's milk, using the DNA filter method. The method is based on the filtration of a warmed (65-70 degrees C) mixture of milk with Triton X-100 through the Synpor nitrocellulose membrane filter, pore size 2 to 5 microns, and subsequent DNA determination of the collected somatic cells by the colour reaction of diphenylamine. A 2ml quantity of distilled water and 4 ml of diphenylamine reagent were added to the membrane filters with somatic cells. The mixture is warmed in water bath at 90 to 100 degrees C for 20 min., then it is cooled, centrifuged (3500 X g, 15 min.), and the optical density is measured at 595 nm. The relation 8 micrograms = 1 million cells was used for the conversion of DNA content to the counts of cells. The average variation coefficient of the determination was 5.9% and the coefficient of correlation between the diphenylamine DNA filter method and the direct microscopy of the somatic cells on membrane filters was r = 0.997. Using the diphenylamine DNA filter method, the counts of somatic cells can also be determined from milk samples stored in frozen condition or from the filters with collected cells kept at the temperature of 4 degrees C (10 days) or 25 degrees C (3 days). Milk stabilized with formaldehyde can also be used for the determination if stored at 4 degrees C.     

Comparison of the effectiveness of Milkofix, a preservative preparation, with traditional preservative agents in the determination of somatic cell count in milk samples using a fluoro-optic-electronic method]

Milkofix (M), a health friendly preservative substance, to be used for milk sample preservation (Trzicky, 1990), was compared with other preservatives. Untreated milk samples (N) were tested against samples treated with sodium azide (A; 0.0085 g NaN3 and 0.0630 g NaCl), bronopol (B; 0.0100 g bronopol and 0.090 g NaCl), potassium dichromate (C; 0.0330 g K2Cr2O7 and 0.0670 g KCl) and Milkofix (M; 0.1250 g). The doses of the preservatives A, B, C and M are per 25 ml milk. The somatic cell counts (SB) were determined on a FOSSOMATIC 90 apparatus (FOSS ELECTRIC, DENMARK). In the treated milk samples taken from individual cows the values of SB counts were significantly higher than in N samples if determined within eight hours after sampling (Tab. I): in A higher by 18.6%, B by 26.3%, C by 26.4% and M by 24.3% (P less than 0.05). The significantly higher values of SB counts were recorded in bulk milk samples treated with preservatives in comparison with N samples immediately after sampling: in A by 6.0%, in B, C and M by 12.9% (P less than 0.01; Tab. II). After one-day storage of N samples at a temperature of 4 degrees C these differences are insignificant (P greater than 0.05), thus the results of N, A, B, C and M samples obtained after one-day storage at 4 degrees C can be taken as actual and mutually comparable.(ABSTRACT TRUNCATED AT 250 WORDS)     

Phase I Evaluation of Doxorubicin and Whole-body Hyperthermia in Dogs with Lymphoma

Fifteen previously untreated dogs with histologically confirmed, high-grade multicentric lymphoma were entered into a phase I study to evaluate combined doxorubicin and whole-body hyperthermia (DOX/WBH). Groups of three, four, and eight dogs were treated with whole-body hyperthermia and concurrent doxorubicin at 12 mg/m2, 24 mg/m2 and 30 mg/m2, respectively, after one doxorubicin induction dose at 30 mg/m2. Plateau temperature (42 +/- 0.1 degree C) was maintained for 90 minutes using a radiant heating device. A total of five DOX/WBH treatments per dog were planned, and these were given every 21 days. Treatment-related toxicity was not seen in the 12-mg/m2 doxorubicin dose group. Tumor progression prohibited administration of more than three DOX/WBH treatments to any dog in the 12-mg/m2 group. Premature ventricular contractions developed after the fifth treatment in one of the four dogs treated with 24 mg/m2 of doxorubicin. Two dogs (25%) in the 30-mg/m2 dose group had treatment-related toxicity. One dog experienced acute serious myelosuppression 1 week after the third treatment. This dog received all planned DOX/WBH treatments. Asymptomatic cardiac toxicosis consisting of decreased ejection fraction and fractional shortening developed in the second dog. This dog received only two DOX/WBH treatments. The three dogs treated at 12 mg/m2 had partial responses of short duration (60-83 days). Four dogs treated at 24 mg/m2 had complete responses for 150, 164, 186, and 200 days. Eight dogs treated at 30 mg/m2 had complete responses with a mean and median duration of 241 and 190 days, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of peripheral blood polymorphonuclear leukocyte function and blood components in Japanese black steers administered ACTH in a cold environment.

An examination of the effects of artificial stress induced by adrenocorticotropin (ACTH) on total and differential leukocyte counts, plasma cortisol levels, metabolic profiles and peripheral blood polymorphonuclear leukocyte (PMN) function was performed on Japanese Black steers kept in a cold environment, with the following regimes; 1) -5 degrees C x ACTH (100 IU/day for 3 days), 2) 0 degrees C x ACTH, 3) 15 degrees C x ACTH and 4) 15 degrees C x PBS. Blood samples were collected before and at 1, 2, 24, 48, 72 and 96 hr prior to the application of the stressor. The plasma cortisol level was found to greatly increase at one hr after the first treatment of ACTH, particularly so in animals exposed to -5 degrees C. Total leukocytes (-5 degrees C and 0 degrees C experiments, respectively), the monocytes (-5 degrees C), neutrophils and eosinophils (-5 degrees C, 0 degrees C and 15 degrees C, respectively) obviously increased just after the first administration, although lymphocyte counts at -5 degrees C were inversely related to those described above. All of these tendencies were augmented by the cold environment except for eosinophils. The chemiluminescent (CL) response of PMN decreased in the ACTH-administered steers at an early stage of post-administration, however, it tended to recover from the lower-than-base value in the cold-affected steers. ACTH administration resulted in higher plasma glucose (Glu) compared to a control, although only steers housed at -5 degrees C evidently showed lower plasma inorganic phosphorus (IP). No abnormal serum acute phase protein, or immunosuppressor, was noted. ACTH thus appears not only to promote physiological reactions but also to temporarily suppress PMN cellular immune function in Japanese Black steers. Although, a cold environment rapidly restored the CL activity to over the pre-administrational value, suggesting that a vital response was activated by crymo-stimuli.     

Availability of infective larvae of parasitic nematodes of sheep grazing on Kikuyu (Pennisetum clandestinum) pastures in the winter rainfall area

Thirteen groups of 4 South African mutton Merinos grazed for 4 weeks with the flock on Kikuyu pastures and were slaughtered for total and differential worm counts at necropsy. Subsequently 12 groups of 8 week tracers grazed on the pastures and were killed for worm counts post mortem. The following were present in most sheep: Teladorsagia (syn. Ostertagia) circumcincta, Trichostrongylus axei, Trichostrongylus colubriformis, Dictyocaulus filaria and Oesophagostomum venulosum. Haemonchus contortus, Nematodirus spathiger and Trichuris skrjabini were less frequently recovered. Optimal conditions for infestation of grazing sheep occurred from June (late autumn)--October (spring) when mean temperatures in any 4 week period were less than 20 degrees C and a total of greater than 40 mm of rain fell on 8 or more separate days. When the mean temperatures exceeded 20 degrees C pastures were safe, sheep acquiring less than 1,000 worms in 4 weeks.     

Artifactual changes in PCV, hemoglobin concentration, and cell counts in bovine, caprine, and porcine blood stored at room and refrigerator temperatures

BACKGROUND: Blood samples collected from farm animals for hematology testing may not reach the laboratory or be examined immediately upon collection, and in some cases may need to be transported for hours before reaching a laboratory. OBJECTIVE: The objective of this study was to investigate the artifactual changes that may occur in PCV, hemoglobin (Hgb) concentration, and cell counts in bovine, caprine, and porcine blood samples stored at room (30 degrees C) or refrigerator (5 degrees C) temperature. METHODS: Baseline values for PCV, Hgb concentration, and RBC and WBC counts were determined immediately after blood collection from 36 cattle, 32 goats, and 48 pigs using manual techniques. Blood samples were split into 2 aliquots and stored at 30 degrees C or 5 degrees C. Hematologic analyses were carried out at specified intervals during 120 hours of storage. Results were analyzed by repeated measure ANOVA; results at different temperatures were compared by paired t-tests. RESULTS: Compared to baseline values, there were no significant changes in Hgb concentration, RBC count, or WBC count in samples from cattle; in Hgb concentration and RBC count in samples from goats; and in Hgb concentration and WBC count in samples from pigs throughout the 120 hours of storage at both 30 degrees C and 5 degrees C. Significant changes (P <.05) from baseline occurred in PCV after 14 hours of storage at 30 degrees C and after 19 hours of storage at 5 degrees C in cattle and goats; and after 10 hours of storage at 30 degrees C and 14 hours of storage at 5 degrees C in pigs. Significant changes also were observed in Hgb concentration at 96 hours at 30 degrees C and 5 degrees C, and in RBC counts at 48 hours at 30 degrees C and 96 hours at 5 degrees C in porcine samples; and in total WBC counts at 120 hours at 30 degrees C and 5 degrees C in caprine samples. Artifactual changes were more pronounced in the samples stored at 30 degrees C. CONCLUSIONS: At both 30 degrees C and 5 degrees C, blood samples from cattle and goats can be stored for up to 12 hours, while blood samples from pigs can be stored for up to 8 hours without any significant changes in PCV. Blood samples from all 3 species can be stored for more than 24 hours without significant changes in Hgb concentration, RBC count, and total WBC count.     

Seasonal comparisons of anthelmintic activity of levamisole pour-on in cattle in the USA

Anthelmintic activity of a pour-on formulation of levamisole, applied during warm weather (16 degrees to 36 degrees C) at 10 mg/kg bodyweight, was evaluated in groups of naturally parasitised calves. This activity was compared to that obtained in similar groups of calves treated in the winter (-4 degrees to +7 degrees C). Controlled efficacy of the pour-on formulation was determined for each season by comparing mean worm burdens in treated calves sacrificed seven to nine days after treatment to non-treated controls. In these trials, burdens of Bunostomum phlebotomum, Cooperia species, Haemonchus placei, Nematodirus species, Oesophagostomum radiatum, Ostertagia ostertagi and Trichostrongylus axei in treated calves were reduced by 83.3 to 100 per cent in the summer and 89.2 to 100 per cent in the winter. Field investigations at nine locations across the USA compared changes in faecal egg counts for cattle treated and evaluated during warm summer months (27 degrees to 36 degrees C) to those treated during cold winter months (-18 degrees to +10 degrees C). Overall, faecal egg counts were reduced by 90.2 per cent in the summer trials and 94.0 per cent in the winter trials. The results of these trials indicate that there is no seasonal variation in the anthelmintic activity of this pour-on formulation of levamisole.     

Plateletcrit is superior to platelet count for assessing platelet status in Cavalier King Charles Spaniels

Background: Many Cavalier King Charles Spaniel (CKCS) dogs are affected by an autosomal recessive dysplasia of platelets resulting in fewer but larger platelets. The IDEXX Vet Autoread (QBC) hematology analyzer directly measures the relative volume of platelets in a blood sample (plateletcrit). We hypothesized that CKCS both with and without hereditary macrothrombocytosis would have a normal plateletcrit and that the QBC results would better identify the total circulating volume of platelets in CKSC than methods directly enumerating platelet numbers.
Objectives: The major purpose of this study was to compare the QBC platelet results with platelet counts from other automated and manual methods for evaluating platelet status in CKCS dogs.
Methods: Platelet counts were determined in fresh EDTA blood from 27 adult CKCS dogs using the QBC, Sysmex XT-2000iV (optical and impedance), CELL-DYN 3500, blood smear estimate, and manual methods. Sysmex optical platelet counts were reanalyzed following gating to determine the number and percentage of normal- and large-sized platelets in each blood sample.
Results: None of the 27 CKCS dogs had thrombocytopenia (defined as <164 × 10⁹ platelets/L) based on the QBC platelet count. Fourteen (52%) to 18 (66%) of the dogs had thrombocytopenia with other methods. The percentage of large platelets, as determined by regating the Sysmex optical platelet counts, ranged from 1% to 75%, in a gradual continuum.
Conclusions: The QBC may be the best analyzer for assessing clinically relevant thrombocytopenia in CKCS dogs, because its platelet count is based on the plateletcrit, a measurement of platelet mass.     

A comparison of platelet parameters in EDTA- and citrate-anticoagulated blood in dogs

BACKGROUND: Platelet aggregates are a common artifact in canine blood. Aggregates may affect the accuracy of platelet counts, with important consequences for patient care. OBJECTIVES: The purpose of this study was to determine if platelet counts in dogs were more accurate if blood was collected into citrate instead of EDTA as an anticoagulant. METHODS: Blood was collected from 50 dogs with neoplasia admitted to the oncology service at Cornell University. EDTA and citrate Vacutainer tubes were filled with blood in random order. Platelet counts and parameters (mean platelet volume [MPV], platelet distribution width [PDW], mean platelet component concentration [MPC], platelet component distribution width [PCDW], and automated platelet clump count [APCC]) were determined using an optical-based hematology analyzer (ADVIA 120). Blood smears from each anticoagulated sample were scored visually for platelet aggregates. RESULTS: The median platelet count was significantly lower (median decrease, 27 x 10(9)/L) in citrate-anticoagulated blood compared with EDTA-anticoagulated blood. This was attributed to platelet activation and aggregation: significantly more aggregates were seen in smears of citrate- than of EDTA-anticoagulated blood. Aggregates were typically small and not detected by the analyzer. Also, the MPV and MPC (or density) were significantly higher (median increase, 3 fL) and lower (median decrease, 33 g/L) in citrate-anticoagulated samples, respectively. CONCLUSIONS: Platelets aggregate, likely from activation, when blood from dogs with neoplasia is anticoagulated with citrate for hematology testing, resulting in lower platelet counts. Citrate also yields inaccurate results for MPV and MPC, likely because of inadequate sphering of platelets. Thus, we recommend that citrate not be used as an anticoagulant when accurate platelet counts are desired in dogs.     

Primary immune-mediated thrombocytopenia in 30 dogs (1997-2003)

During a 6-year period, primary (idiopathic) immune-mediated thrombocytopenia was retrospectively evaluated in 30 dogs. Ages of the dogs ranged from 3 months to 10 years (median 4 years); female dogs were markedly overrepresented with 73%. Clinical examination revealed hemorrhages in 70% of the dogs. Platelet counts ranged from 0 to 111,000/microL (median 8000/microL); 77% of the dogs had platelet counts <30,000/microL. Seventeen dogs were anemic (hematocrit 9% to 36%; median 31%). Immunosuppressive therapy was performed in all but one dog. The recurrence rate of 19 dogs that were followed over an extended period (112 to 1684 days; median 340 days) was 26%. Twenty-nine (97%) dogs survived 14 days after initial presentation, and 27 (93%) dogs survived at least the following 15 to 1684 days (median 220 days).     

The effect of storage conditions on samples for the evaluation of copper status in blesbok (Damaliscus pygargus phillipsi)

Investigaltions to determine the effect of sample storage on the concentration of copper in liver tissue and on the activity of erythrocyte superoxide dismutase were undertaken in preparation for a study of blesbok (Damaliscus pygargus phillipsi) that were suspected to be suffering from copper deficiency. Two liver samples were collected from each of 20 culled blesbok in a manner that simulated the collection of biopsies from the live animal. These samples were stored either in 10% formalin or frozen at -20 degrees C until analysed 4 1/2 months later. The effect of different methods of sample storage on superoxide dismutase activity was determined. Erythrocytes collected from 3 Jersey cows and 5 culled blesbok were washed and divided into 0.5 ml portions, stored at room temperature (approximately 20 degrees C), in a refrigerator (4 degrees C), frozen at -20 degrees C in a freezer, and in liquid nitrogen (-200 degrees C). An analysis of superoxide dismutase activity was undertaken using a commercial assay kit at intervals of 2-4 days until the levels of activity had fallen significantly. The copper concentration in formalin-preserved liver samples was significantly lower than that measured in frozen liver tissue apparently as a result of leaching. The activity of superoxide dismutase in cattle blood was unchanged for 4 days at room temperature but fell appreciably after 2 days at 4 degrees C and -20 degrees C. Enzyme activity remained unchanged for 200 days in erythrocytes stored in liquid nitrogen. Superoxide dismutase activity levels in healthy blesbok were considerably lower than those measured in Jersey cows and remained unaffected for up to 6 days in samples stored at 4 degrees C and 20 degrees C. The level of activity fell significantly thereafter. Samples stored in liquid nitrogen were unchanged after 40 days.