A 2-year-old neutered male domestic cat was referred for possible perineal urethrostomy because of a history of recurring bouts of cystitis and urethral obstruction. Results of the physical examination were unremarkable, and the bladder was easily expressed. Results of serum biochemical analysis and a CBC from the referring veterinarian were within reference limits except for a high concentration of glucose (166 mg/dL; range, 76 to 145 mg/dL). Abdominal ultrasonography was performed to further evaluate the urinary bladder (Figure 1).
Transverse ultrasonographic image of the liver and gallbladder of a 2-year-old neutered male domestic cat with
Objective—To determine whether platelet clumps
are homogeneously distributed in blood samples, and
whether platelet concentrations (PC) obtained by use
of impedance and buffy coat analysis can be considered
minimum values when platelet clumps are present.
Sample Population—50 blood samples obtained
from 30 dogs.
Procedure—10 blood samples containing platelet
clumps were used and 10 smears were made from
each sample; amount of platelet clumping was graded
for all 100 smears. Blood from each of 20 healthy
dogs was divided between 2 EDTA tubes before and
after platelet clumping was induced by adenosine
diphosphate (ADP). The PC for each ADP-treated and
untreated sample were measured, using impedance
and quantitative buffy coat analyzers.
Results—Platelet clumps were evident in all 100
blood smears, but the amount of clumping varied considerably
within some samples. Using the impedance
analyzer, the PC of ADP-treated samples were significantly
lower and never higher than the PC of untreated
samples. Using the buffy coat analyzer, some ADPtreated
samples had increased PC; however, significant
differences were not detected between treated
and untreated samples.
Conclusions and Clinical Relevance—Platelet
clumping was not homogeneous within blood samples.
When platelet clumps were identified by direct
examination of blood smears, the PC detected by use
of the impedance analyzer could be considered minimum
values. In contrast, the PC detected by use of
the buffy coat analyzer were sometimes increased.
Useful information can be obtained by measuring PC
in blood with platelet clumps; values obtained by use
of impedance can be considered minimums, and values
obtained by use of buffy coat analysis may be
either minimum values or reasonable estimates of
PC. (J Am Vet Med Assoc 2001;219:1552–1556)
Objective—To determine erythrocyte survival time in Greyhounds.
Animals—6 Greyhounds used as blood donors and 3 privately owned non-Greyhound dogs.
Procedures—In vivo biotinylation of erythrocytes was performed by infusion of biotin—Nhydroxysuccinimide into each dog via a jugular vein catheter. Blood samples were collected 12 hours later and then at weekly intervals and were used to determine the percentage of biotin-labeled erythrocytes at each time point. Erythrocytes were washed, incubated with avidin—fluorescein isothiocyanate, and washed again before the percentage of biotinylated erythrocytes was measured by use of flow cytometry. Survival curves for the percentage of biotinylated erythrocytes were generated, and erythrocyte survival time was defined as the x-intercept of a least squares best-fit line for the linear portion of each curve.
Results—The R for survival curves ranged from 0.93 to 0.99 during the first 10 weeks after infusion of erythrocytes. Erythrocyte survival time for the 3 non-Greyhound dogs was 94, 98, and 116 days, respectively, which was consistent with previously reported values. Erythrocyte survival time for the 6 Greyhounds ranged from 83 to 110 days (mean, 93 days; median, 88 days). As determined by use of in vivo biotinylation, erythrocyte survival times in Greyhounds were similar to those determined for non-Greyhound dogs and did not differ significantly from erythrocyte survival times reported previously for non-Greyhound dogs.
Conclusions and Clinical Relevance—Erythrocyte survival time was similar in Greyhounds and non-Greyhound dogs. Greyhounds can be used as erythrocyte donors without concerns about inherently shorter erythrocyte survival time. (Am J Vet Res 2010;71:1033–1038)
Objective—To establish reference values for activated
coagulation time (ACT) in cats by use of jugular
venipuncture and direct collection of blood into ACT
Animals—100 clinically normal cats that were to have
elective surgery performed at a private practice.
Procedure—Collection of 3 blood samples for ACT
measurement was attempted for each cat at the time
of elective surgery: sample 1, obtained before sedation;
sample 2, tube 1 of 2 consecutive samples
obtained from a single venipuncture of the contralateral
jugular vein after sedation with acepromazine
and ketamine hydrochloride; and sample 3, tube 2
collected immediately following collection of sample
2 without removing the needle from the vein.
Venipuncture quality was rated subjectively on a 3-
Results—Median ACT were 95 seconds for each
sample group. The middle 95% of values ranged
inclusively from 55 to 185 seconds (sample 1), 65 to
135 seconds (sample 2), 45 to 145 seconds (sample
3), and 55 to 165 seconds overall (samples 1, 2, and
3). Significant differences in ACT values were not
detected between sample groups. Significant relationships
between ACT and venipuncture quality or
sex of cat were not detected.
Conclusions and Clinical Relevance—With the ACT
protocols used, clinically normal cats had ACT of
< 165 seconds. The ACT in cats does not appear to be
significantly affected by sex, sedation with acepromazine
and ketamine, or by moderately traumatic
venipunctures. These results refute widespread statements
that ACT should be < 65 seconds in healthy
cats. Cats with ACT repeatedly > 165 seconds should
be further evaluated for hemostatic disorders. (Am J
Vet Res 2000;61:750–753)
Objective—To develop a direct assay to measure
platelet surface-associated immunoglobulins (PSAIg)
in dogs and to determine whether the assay is useful
in the diagnosis of immune-mediated thrombocytopenia
Animals—20 healthy dogs were used to develop reference
intervals, and 23 dogs with IMT and 17 with
non-IMT were used to evaluate the clinical use of this
Procedure—After optimization of platelet collection
and assay conditions, concentrations of PSAIg were
measured, using radiolabeled staphylococcal protein
A (SpA) and polyclonal antibodies against canine IgG
(anti-γ) and IgM (anti-µ). Concentrations of PSAIg
were expressed as the percentage of radiolabeled
immunoglobulin detector bound.
Results—Cut-off values (mean + 3 SD) were as follows:
SpA, 1.1%; anti-γ, 1.3%; and anti-µ, 3.5%.
Values greater than these cut-off values were considered
positive. Values determined by use of radiolabeled
SpA for all dogs with IMT were greater than the
cut-off value; values were considered high positives
(> 5 times cut-off value) for 22 of these 23 dogs.
Although 9 of 17 dogs with non-IMT also had PSAIg
concentrations greater than the cut-off value, values
were considered high positives for only 3 of these 9
Conclusion and Clinical Relevance—The immunoradiometric
assay developed is a reliable and sensitive
method to detect PSAIg in dogs. However, to obtain
accurate results, optimum temperature, time, and
storage conditions must be used. Detection of
increased concentrations of PSAIg in dogs presumed
to have non-IMT should alert clinicians to reconsider
an immune-mediated basis for the thrombocytopenia.
(Am J Vet Res 2002;63:124–136)
OBJECTIVE To develop and characterize flow cytometric assays for detecting IgG bound to canine erythrocytes and bone marrow erythroid precursors.
SAMPLE Blood samples from 20 healthy and 61 sick dogs with (n = 33) or without (28) immune-mediated hemolytic anemia (IMHA) and bone marrow samples from 14 healthy dogs.
PROCEDURES A flow cytometric assay for measurement of IgG on RBCs was developed, and appropriate positive control cells were generated. Analytic and diagnostic performance were characterized. The RBC IgG assay was then combined with density-gradient fractionation of aspirated bone marrow cells and a 2-color process to yield an assay for detecting IgG on nucleated RBCs (nRBCs). Cell sorting and cytologic examination confirmed target cell populations, and anti–dog erythrocyte antigen 1 (DEA1) blood-typing serum was used to generate IgG-positive nRBCs.
RESULTS Within- and between-run coefficients of variation for the RBC IgG assay were 0.1% to 13.9%, and > 90% of spiked IgG-positive RBCs were detected. Diagnostic sensitivity and specificity of the assay for detection of IMHA were 88% and 93%, respectively. Cytologic findings for sorted bone marrow fractions rich in early-, mid-, and late-stage nRBCs from 3 healthy dogs indicated 89% to 98% nRBC purity. After IgG coating with anti-DEA1 blood-typing serum, IgG was detected on nRBCs from DEA1-positive, but not DEA1-negative, healthy dogs.
CONCLUSIONS AND CLINICAL RELEVANCE The developed RBC IgG assay had favorable analytic and diagnostic performance for detection of IMHA in dogs and was successfully adapted to detect IgG on canine nRBCs of various maturation stages. The findings supported the presence of DEA1 on canine nRBCs.
Objective—To compare the results of regulatory
screening and confirmation assays with those of highperformance
liquid chromatography (HPLC) in the
detection of ceftiofur metabolites in the tissues of
culled dairy cattle.
Animals—17 lactating Holstein dairy cows.
Procedure—Daily IM injections of ceftiofur sodium
were administered at a dose of 2.2 mg of ceftiofur
equivalents/kg (n = 6) or 1.0 mg of ceftiofur equivalents/kg (10) for 5 days. Following withdrawal times of
12 hours (high-dose ceftiofur) and either 5 or 10 days
(low-dose ceftiofur), cows were slaughtered and liver,
kidney, and diaphragmatic muscle specimens were
harvested and analyzed by HPLC and standard regulatory
methods that included the following assays:
the swab test on premises, the fast antimicrobial
screen test, the calf antibiotic and sulfa test, and the
7-plate bioassay confirmation test.
Results—In all tissue specimens, residues of ceftiofur
and desfuroylceftiofur-related metabolites, as
measured by HPLC, were less than regulatory tolerance,
as defined by the FDA. False-positive screening
assay results were more likely for tissue specimens
that had been frozen for shipment to a federal laboratory,
compared with fresh tissue specimens that
were assayed at the slaughter establishment (23% vs
3% false-positive results, respectively).
Conclusions and Clinical Relevance—The observation
that fresh tissues had negative results on screening
assays, whereas subsets of the same tissue specimens
had false-positive results on screening assays
following freezing, suggests that freezing and thawing
interferes with microbial inhibition-based regulatory
screening assays. (Am J Vet Res 2004;65:1730–1733)
Objective—To evaluate changes in serial hemograms and serum biochemical profiles in tumor-bearing dogs undergoing daily anesthesia with propofol as an induction agent for radiation therapy.
Design—Retrospective case series.
Animals—31 dogs with cutaneous or subcutaneous malignancies over the trunk or limbs.
Procedures—Radiation therapy consisted of 18 daily treatments administered Monday through Friday over a period of 24 days. Propofol was administered IV to effect for induction of anesthesia. Complete blood count and serum biochemical data were generated at the beginning, middle, and end of radiation therapy and compared to identify changes over time via either a repeated-measures ANOVA or Friedman test.
Results—Leukocyte and platelet parameters did not differ significantly over time. Calculated Hct, erythrocyte count, hemoglobin concentration, and mean corpuscular hemoglobin concentration decreased overtime, whereas mean corpuscular volume increased overtime.
Conclusions and Clinical Relevance—Dogs receiving propofol for induction of anesthesia and radiation therapy had a decrease in RBC count, although these changes were not determined to be of clinical importance in this patient population. The cause of these alterations was not immediately apparent. Propofol appeared to be a safe choice for induction of anesthesia in dogs during daily radiation therapy.
Inferential studies to investigate the health of rare, exotic, or companion animals are often challenging because sample groups of sufficiently large sizes are difficult to obtain. This may be a result of limited availability of exotic or endangered animals or the ethical desire to limit the number of animals involved in painful or terminal studies. In standard study designs with adequate statistical power, the number of animals required for inclusion is often greater than the number that can be obtained or feasibly managed. Also, the cost of providing long-term care for research animals is often greater than the available funding
Objective—To determine effects of vaccination protocols with modified-live porcine reproductive and respiratory syndrome virus (PRRSV) vaccine on persistence and transmission of virus in pigs infected with a homologous isolate and determine clinical and virologic responses following heterologous viral challenge.
Animals—Four hundred forty 6- to 8-week-old PRRSV-naïve pigs.
Procedures—Pigs were allocated into 5 groups. Groups A to D were inoculated with wild-type PRRSV VR2332. Group A (positive control pigs) received PRRSV only. Groups B, C, and D received modified-live PRRSV vaccine (1, 2, or 3 doses). Group E served as a negative control group. To evaluate viral transmission, sentinel pigs were introduced into each group at intervals from 37 to 67, 67 to 97, and 97 to 127 days postinoculation (DPI). To evaluate persistence, pigs were euthanized at 37, 67, 97, or 127 DPI. To assess clinical and virologic response after challenge, selected pigs from each group were inoculated at 98 DPI with a heterologous isolate (PRRSV MN-184).
Results—Mass vaccination significantly reduced the number of persistently infected pigs at 127 DPI. Vaccination did not eliminate wild-type PRRSV; administration of 2 or 3 doses of modified-live virus vaccine reduced viral shedding after 97 DPI. Previous exposure to wild-type and vaccine virus reduced clinical signs and enhanced growth following heterologous challenge but did not prevent infection.
Conclusions and Clinical Relevance—Findings suggest that therapeutic vaccination may help to reduce economic losses of PRRSV caused by infection; further studies to define the role of modified-live virus vaccines in control-eradication programs are needed.