Effect of exogenous somatotropin on hematological variables of lactating cows and their offspring.

Eighty-two lactating Holstein cows in their first, second, or third lactation received either one, three, or five concurrent i.m. injections of a unit dose (0.6 g) of zinc methionyl bovine somatotropin (bST) or five doses of the vehicle. Injections were administered at 14-d intervals from 60 +/- 3 d postpartum until the end of lactation or until necropsy. Thirty-eight cows were continued on the treatment for a 2nd yr. Blood samples were collected at wk -2, -1, 3, and 7 relative to the start of treatment and then every 8 wk (yr 1) or 4 wk (yr 2) thereafter. Untreated cows that were included in a survey of the resident herd were bled at wk 7 or 8, wk 10 or 11, and wk 13 or 14 of lactation and every 4 or 8 wk thereafter. Calves were bled within 72 h of birth and at approximately 5 wk of age. Most parameters associated with erythrocytes were decreased mildly in cows that were treated with bST. However, data remained within generally accepted reference ranges, and changes were not of clinical importance. Decreased hematocrit was not associated with increased hemolysis, hemodilution, or clinical anemia. No morphological lesions related to treatment were noted in the bone marrow or spleen; bST did not affect the incidence of immature cell types. Energy and protein balances did not significantly affect the hematological results of the cows. Calves generally were unaffected by bST treatment of the dam, but heavier calves had higher parameters associated with erythrocyte and lymphocyte counts than did calves with lower body weight. Exogenous bST treatment caused predictable changes in hematological parameters of dairy cows.

Clinical pathology of llamas.

Clinical evaluation of the llama patient incorporates procedures and measurements similar to those used in the diagnosis of disease in other animals. These commonly include clinical laboratory measurements. This article reports on the improvements in our knowledge of clinical laboratory variables in llamas.

Flow cytometric analysis of feline reticulocytes.

Hemolytic anemia was induced in five Domestic Shorthair cats (four adult males and one spayed female obtained from a breeding colony at Colorado State University, CO), and blood samples were analyzed from five other cats (two castrated male Domestic Shorthairs, one castrated male Domestic Longhair, one castrated male Persian, and one spayed female Siamese presented to the Veterinary Teaching Hospital at Colorado State University for miscellaneous problems). Blood samples taken from these cats had percentages of aggregate reticulocytes that ranged from 0% to 14.5% as determined by manual counting and were used to identify the best technique for staining cat reticulocytes for flow cytometric analysis. The best technique was mixing a blood sample (1/2,000 dilution) with 0.2 micrograms thiazole orange in 1 ml of diluent and incubating the mixture in the dark at room temperature for 30 to 60 minutes. The percentage of reticulocytes determined by flow cytometry correlated well (r = 0.88) with manually determined aggregate reticulocyte percentages; no significant differences were observed between the two techniques (P > 0.05). For the conditions used, punctate reticulocytes were not detected by flow cytometry. Samples with very high platelet numbers and very low packed cell volumes may show falsely elevated percentages of reticulocytes as determined by flow cytometry. The reproducibility of the flow cytometric technique was good; the coefficient of variation ranged from 4.8% to 17.9% in two samples with two different times of incubation. Staining of cat aggregate reticulocytes with thiazole orange and use of flow cytometric quantification is a reproducible technique that has a good correlation with the manual reticulocyte counting method.

Reference hematologic values and morphologic features of blood cells in healthy adult llamas.

Hematologic values and cellular morphologic features were evaluated for 38 healthy adult llamas. Reference ranges were determined for PCV, reticulocyte concentration, leukocyte concentration, and leukocyte differential counts. The approach used in this study was to focus on hematologic values that may be determined by use of techniques readily available to the practicing veterinarian and nonveterinary laboratory. Unique cellular morphologic features commonly observed and interpreted as normal included large granular lymphocytes, hyposegmented eosinophil nuclei, folded erythrocytes, and hemoglobin crystals.

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.

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.

Comparative biological responses of rabbits infected with human T-lymphotropic virus type I isolates from patients with lymphoproliferative and neurodegenerative disease.

An experimental rabbit model was used to determine host responses to infection by various human T-lymphotropic virus type-I (HTLV-I) strains. Seven groups of 4 to 5 rabbits each were inoculated with lethally-irradiated HTLV-I-infected cell lines derived from patients with adult T-cell leukemia/lymphoma or from patients with HTLV-I-associated myelopathy. Four separate control groups of 2 rabbits each were inoculated with similarly prepared HTLV-I-negative cells derived from rabbits or humans. Anti-viral antibody responses were assessed by immunoblot assay and hematologic parameters were measured using automated cell counters and cytologic staining. The virologic status of challenged rabbits was determined by co-culture and HTLV-I antigen capture assay, as well as by polymerase chain reaction (PCR) amplification of HTLV-I DNA from peripheral blood mononuclear cells (PBMC) or tissues. The HTLV-I inocula could be separated into groups based upon their infectivity to rabbits: highly infectious strains elicited intense serologic responses and were detected frequently in tissues by antigen and PCR assays, while other strains were moderately to poorly infectious, induced weak antibody responses and were infrequently detected by antigen and PCR assays. Overall, PBMC appeared to have the greatest quantity of HTLV-I containing cells, while bone marrow was a poor source of virus. No clinical or hematologic abnormalities were evident during the 24-week course of infection. Taken together, our results suggest there is heterogeneity in the biological response to HTLV-I infection which is, in part, dependent on the infecting strain of virus.

Infectious transmission of human T-cell lymphotropic virus type II in rabbits.

To determine the susceptibility of rabbits to experimental infection with human T-cell lymphotropic virus type-II (HTLV-II), four separate groups of four weanling rabbits each were inoculated intravenously with lethally irradiated HTLV-II-infected human cell lines Mo-T (HTLV-IIMo-infected T cells), WIL-NRA (an Epstein-Barr virus [EBV]-transformed B-lymphoblastoid cell line infected with HTLV-IINRA), 729pH6neo (an EBV-transformed lymphoblastoid cell line transfected with a molecular clone of HTLV-IIMo), or G12.1 (HTLV-II-infected T cells from a Panamanian Guaymi Indian). Two additional groups of four rabbits each were similarly inoculated with control uninfected 729 or HuT 78 cells. Early and persistent seroconversion to HTLV-II core antigen p24, as determined by Western immunoblot, occurred in all HTLV-II-inoculated rabbits and was most intense in rabbits inoculated with G12.1 cells; seroreactivity to other HTLV-II gag or env antigens occurred later, with less intensity, or not in all inoculated rabbits. Peripheral blood mononuclear cells (PBMC) and other lymphoid cells from HTLV-II-inoculated rabbits produced minimal p24 in vitro, as determined by enzyme immunosorbent capture assay. Virus was more readily detected by polymerase chain reaction amplification of HTLV-II pol sequences; this occurred most frequently in rabbits inoculated with Mo-T cells, and most frequently in PBMC as compared with other tissues tested (bone marrow, brain, and liver). No evidence of disease occurred in HTLV-II-inoculated rabbits observed for as long as 24 weeks. All control rabbits remained negative for evidence of HTLV-II infection, as determined by the same procedures. These results provide the first evidence of HTLV-II infection in a species other than humans, and demonstrate the usefulness of the rabbit as an animal model to study the biologic response to different isolates of this human retrovirus.

The clinicopathologic, light, and scanning electron microscopic features of eperythrozoonosis in four naturally infected llamas.

The hematologic, biochemical, and light and scanning electron microscopic features of eperythrozoonosis in four llamas are described. One female and three male yearling llamas were presented for evaluation of chronic weight loss. Three of four llamas had historical evidence of chronic inflammatory conditions. On examination, multiple clinical problems were apparent, including poorly to non-regenerative anemia, inflammatory disease, and hypoproteinemia. Coccoid- and ring-shaped basophilic organisms were present on the erythrocytes of all the llamas. On scanning electron microscopy, individual, pairs, and clusters of coccoid-shaped organisms were present on the erythrocytes. The organisms measured 0.4 to 0.6 micron in diameter and caused no marked deformation of the erythrocyte membrane. A rare organism could be found that produced a slight indentation into the erythrocyte membrane. The light and scanning electron microscopic morphologic features suggested that the organism was an Eperythrozoon. Serial evaluation of serum iron concentrations of the llamas showed a decrease serum iron in all animals, with a concurrent decrease in the total iron binding capacity and percent transferrin saturation in two of the llamas. Common abnormalities seen on serum electrophoresis included a decrease in albumin and beta serum fraction in all llamas and a decrease in the gamma globulin fraction of two individuals.

Development of an enzyme-linked immunosorbent assay to detect IgG, IgM, and complement (C3) on canine erythrocytes.

An ELISA was used to detect IgG, IgM, and complement (C3) on the surface of canine erythrocytes. Erythrocytes were placed in wells of a microtitration plate and incubated with affinity purified, alkaline phosphatase-conjugated anti-canine IgG, IgM, or C3. Results of the ELISA were compared with the direct antiglobulin test (DAT) by preparing standard reference curves from canine blood type A erythrocytes that had been incubated with serial dilutions (1:2 to 1:8, 192) of canine anti-A serum. The ELISA detected increased erythrocyte-bound immunoglobulin and complement at two- to fourfold dilutions greater than those required for positive results with the DAT. The ELISA required small sample and reagent volumes and detected lower concentrations of immune components than did the DAT.

Chronic flunixin meglumine therapy in foals.

Effects of a therapeutic dose of flunixin meglumine on gastric mucosa of horse foals were determined by endoscopy, double-contrast radiography, and gross and histologic examinations. Foals were administered 1.1 mg of flunixin meglumine/kg of body weight, PO/day for 30 days in an encapsulated form that was divided into 2 doses/day (group 1; n = 3) or by IM injection once a day (group 2; n = 7). Three control foals (group 3; n = 3) were administered capsules (n = 1) containing dextrose powder or IM injections (n = 2) of vehicle solution without flunixin meglumine. All 3 groups-1 foals given flunixin meglumine PO developed oral ulcers. Group-2 foals given flunixin meglumine IM did not develop oral ulcers. One control foal (group 3) developed 1 oral ulcer that healed during the study. Endoscopic examination revealed linear crease-like mucosal lesions in the glandular portion of the stomach in 2 group-2 foals. Radiographic evidence of gastric ulcers was observed in only 1 gastrogram of a group-1 foal. Foals were euthanatized, and necropsy revealed erosions and/or ulcers of the glandular portion of the stomach. Oral ulcers were observed in all 3 group-1 foals. Erosions of the glandular portion of the stomach developed in all 10 foals given flunixin meglumine, but did not develop in group-3 foals. Ulceration of the glandular portion of the stomach was present in 1 group-2 foal.

Size referenced electronic leukocyte counting threshold and lysed leukocyte size distribution of common domestic animal species.

Using a single channel electronic cell counter and attached particle size analyzer, leukocyte size distribution histograms were determined on canine, feline, bovine, and equine blood diluted with chloride-based diluent and treated with a conventional stromatolysin. Histograms were usually unimodal, but a few were bimodal. Mean values for mean lysed leukocyte particle volume were 49.2, 51.1, 55.4, and 65.0 fl for canine, feline, equine, and bovine blood, respectively. From inspection of histograms, a lower threshold of 30 fl referenced to latex spheres was interpreted to be appropriate for counting leukocytes of these four species simultaneously. Debris below the threshold was seen in many samples and was usually separated from the leukocyte population by a valley touching the histogram baseline at the threshold channel. Debris resulted in a visually detectable threshold failure by extending considerably into the leukocyte size range in 9% of feline, 9% of canine, and 7% of bovine samples. It is recommended that careful establishment of the lower counting threshold will minimize frequency and severity of leukocyte count error associated with failure to exclude debris.

Immune-mediated hemolytic anemia and thrombocytopenia in a foal.

A one-month-old Quarter Horse filly had unilateral epistaxis, hyphema, icterus, petechial hemorrhages in the oral, nasal, conjunctival, and vulvar mucous membranes, anemia, thrombocytopenia, negative antinuclear test result, and a positive direct Coombs' test result. Megakaryocytes or cell-associated IgG (fluorescent antibody and immunoperoxidase stains) were not found in bone marrow biopsy specimens. Treatment consisted of glucocorticoids, antibiotics, and a single whole blood transfusion. The foal responded well to treatment, did not develop relapses of the disease, and was clinically normal one year after treatment.

Modification and evaluation of a multichannel blood cell counting system for blood analysis in veterinary hematology.

A multichannel, semiautomated, blood cell counting system (Coulter Counter Model S550) was modified for use in veterinary hematology by increasing both the erythrocyte and leukocyte aperture currents to 225 V and 195 V, respectively, followed by calibration with human blood. It was evaluated by use of 350 samples from dogs, cats, horses, and cows. Values for leukocyte count, erythrocyte count, mean corpuscular volume, and hematocrit generated by the S550 were compared with values generated by an automated multichannel counter with histogram capability and other reference procedures when appropriate. Mean differences for values between S550 and reference values were less than calibration tolerance limits for the instrument. Correlation coefficients were excellent for all values of each species. To assess behavior of leukocytes of the different species with respect to the counting threshold, leukocyte size distribution histograms were generated for all samples analyzed on the S550. Means for mean leukocyte volumes in diluent and lysing reagents were 55.5, 56.6, 67.4, and 72.8 fl for dogs, cats, horses, and cows, respectively. Canine leukocyte counts, because of small leukocyte size, were an average of 14% less for 5 samples analyzed on the unmodified instrument, compared with analysis after increasing the leukocyte aperture current. Leukocyte threshold failures attributable to interfering particles, resulting in falsely high counts, were recognized in 14%, 10%, 8% and 0% of feline, bovine, canine, and equine samples, respectively. The magnitude of error in these samples averaged 5% for cows and dogs, but was considered not important. However, leukocyte counts of feline samples in this group averaged 44% falsely high.

Electronic measurement of erythrocyte volume and volume heterogeneity in horses during erythrocyte regeneration associated with experimental anemias.

Anemia was induced in three groups of horses by moderate or severe acute hemorrhage, or by acetyl phenylhydrazine-induced hemolysis (Groups I, II, and III, respectively). Serial hemograms were done on a multichannel automated blood cell counter with histogram capability. Changes in hematocrit, mean cell volume, erythrocyte number, red cell distribution width (RDW), and standard deviation of erythrocyte volume were examined over time. Significant increases in mean cell volume were first detectable by days 17, 20, and 14 and reached maximum by days 43, 41, and 29, in Groups I, II, and III, respectively (P less than 0.05). Increased mean cell volume was interpreted as reflecting accelerated erythrocyte regeneration; however, not all horses with accelerated regeneration had changes in mean cell volume. Estimated erythrocyte production rate correlated poorly with hematocrit nadir and change in mean cell volume (r = 0.37 and r = 0.36, respectively, P greater than 0.05). In some horses effective regeneration occurs without development of macrocytosis. Mean cell volume remained increased after other parameters returned to control values, suggesting that mean cell volume values may provide retrospective evidence of altered erythrocyte turnover. Anisocytosis as indicated by significant increases in the standard deviation was greatest during the early part of the regenerative response, reaching maximum values on days 30, 28, and 21 in Groups I, II, and III, respectively, and began to decrease as homogeneous repopulation with macrocytes occurred. Red cell distribution width increased significantly only in severe hemorrhage and hemolysis groups, reaching mean maximum values of 24.3 on day 20 and of 26.4 on day 21 in Groups II and III, respectively (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)