Objective—To develop a reticulocyte classification scheme, optimize an avian reticulocyte staining protocol, and compare the percentages of reticulocyte types with polychromatophil percentage in blood samples from birds.
Sample Population—Blood samples from a red-tailed hawk and 31 ill birds.
Procedures—A single blood sample obtained from a red-tailed hawk (Buteo jamaicensis) was used to optimize the staining protocol. For optimization of the staining protocol, 4 dilutions of whole blood with new methylene blue stain and 4 incubation times were evaluated. From samples submitted for avian CBCs, EDTA-anticoagulated whole blood samples from 31 ill birds were randomly selected and examined to compare polychromatophil and reticulocyte percentages. Reticulocyte staining was performed in all samples by use of a 1:3 (whole blood to new methylene blue) dilution with incubation for 10 minutes at room temperature (approx 22°C); reticulocytes were assessed as a percentage of 1,000 RBCs by 2 independent observers. In Wright-Giemsa–stained blood smears, a polychromatophil percentage was similarly determined.
Results—4 avian reticulocyte types were defined: ring-form reticulocytes, aggregate reticulocytes, and 2 subcategories of punctate reticulocytes. A reticulocyte-staining protocol was optimized. Interobserver and intraobserver variations in assessment of reticulocyte and polychromatophil percentages were not significant. A strong positive correlation (Spearman coefficient of rank correlation [ρ] = 0.978) was identified between the percentage of polychromatophils and the percentage of ring-form reticulocytes.
Conclusions and Clinical Relevance—Results indicated that quantification of ring-form reticulocytes provides an accurate assessment of erythrocyte regenerative capacity in birds.
Objective—To determine clinical characteristics of
dogs that received massive transfusion and identify
the underlying diseases, complications, and outcomes.
Procedure—Medical records of dogs receiving a
massive blood transfusion were evaluated for transfusion
volume, underlying disease process or injury,
benefits and complications of transfusion, and outcome.
A massive transfusion was defined as transfusion
of a volume of blood products in excess of the
patient's estimated blood volume (90 ml/kg [40 ml/lb])
in a 24-hour period or transfusion of a volume of blood
products in excess of half the patient's estimated
blood volume in a 3-hour period.
Results—Six dogs had intra-abdominal neoplasia
resulting in hemoabdomen, 3 had suffered a traumatic
incident resulting in hemoabdomen, and 6 had nontraumatic,
non-neoplastic blood loss. Mean volumes
of packed RBC and fresh-frozen plasma administered
were 66.5 ml/kg (30 ml/lb) and 22.2 ml/kg (10 ml/lb),
respectively. All dogs evaluated developed low ionized
calcium concentrations and thrombocytopenia.
Transfusion reactions were recognized in 6 dogs.
Four dogs survived to hospital discharge.
Conclusions and Clinical Relevance—Results suggest
that massive transfusion is possible and potentially
successful in dogs. Predictable changes in electrolyte
concentrations and platelet count develop. (J
Am Vet Med Assoc 2002;220:1664–1669)
Objective—To investigate effects of lidocaine hydrochloride administered IV on mucosal inflammation in ischemia-injured jejunum of horses treated with flunixin meglumine.
Procedures—Horses received saline (0.9% NaCl) solution (SS; 1 mL/50 kg, IV [1 dose]), flunixin meglumine (1 mg/kg, IV, q 12 h), lidocaine (bolus [1.3 mg/kg] and constant rate infusion [0.05 mg/kg/min], IV, during and after recovery from surgery), or both flunixin and lidocaine (n = 6/group). During surgery, blood flow was occluded for 2 hours in 2 sections of jejunum in each horse. Uninjured and ischemia-injured jejunal specimens were collected after the ischemic period and after euthanasia 18 hours later for histologic assessment and determination of cyclooxygenase (COX) expression (via western blot procedures). Plasma samples collected prior to (baseline) and 8 hours after the ischemic period were analyzed for prostanoid concentrations.
Results—Immediately after the ischemic period, COX-2 expression in horses treated with lidocaine alone was significantly less than expression in horses treated with SS or flunixin alone. Eighteen hours after the ischemic period, mucosal neutrophil counts in horses treated with flunixin alone were significantly higher than counts in other treatment groups. Compared with baseline plasma concentrations, postischemia prostaglandin E2 metabolite and thromboxane B2 concentrations increased in horses treated with SS and in horses treated with SS or lidocaine alone, respectively.
Conclusions and Clinical Relevance—In horses with ischemia-injured jejunum, lidocaine administered IV reduced plasma prostaglandin E2 metabolite concentration and mucosal COX-2 expression. Coadministration of lidocaine with flunixin ameliorated the flunixin-induced increase in mucosal neutrophil counts.
Objective—To describe the pharmacokinetics of N-acetylcysteine (NAC) in healthy cats after oral and IV administration.
Animals—6 healthy cats.
Procedures—In a crossover study, cats received NAC (100 mg/kg) via IV and oral routes of administration; there was a 4-week washout period between treatments. Plasma samples were obtained at 0, 5, 15, 30, and 45 minutes and 1, 2, 4, 8, 12, 24, 36, and 48 hours after administration, and NAC concentrations were quantified by use of a validated high-performance liquid chromatography–mass spectrometry protocol. Data were analyzed via compartmental and noncompartmental pharmacokinetic analysis.
Results—Pharmacokinetics for both routes of administration were best described by a 2-compartment model. Mean ± SD elimination half-life was 0.78 ± 0.16 hours and 1.34 ± 0.24 hours for the IV and oral routes of administration, respectively. Mean bioavailability of NAC after oral administration was 19.3 ± 4.4%.
Conclusions and Clinical Relevance—The pharmacokinetics of NAC for this small population of healthy cats differed from values reported for humans. Assuming there would be similar pharmacokinetics in diseased cats, dose extrapolations from human medicine may result in underdosing of NAC in cats with acute disease. Despite the low bioavailability, plasma concentrations of NAC after oral administration at 100 mg/kg may be effective in the treatment of chronic diseases.
Objective—To identify complications associated with
tibial plateau leveling osteotomy (TPLO) for treatment
of cranial cruciate ligament rupture in dogs and
assess owner perceptions of outcome.
Animals—193 dogs that underwent unilateral or
bilateral TPLO (253 TPLOs total) between November
1997 and March 2001.
Procedure—Complications associated with the surgical
procedure were recorded. A questionnaire was
sent to owners of all dogs to assess their perceptions
Results—Complications were identified in 47 of the
193 (24.4%) dogs and in association with 52 of the
253 (20.6%) TPLOs. Dogs that underwent bilateral
TPLOs during a single anesthetic episode had a higher
complication rate than did dogs that underwent
unilateral TPLO and dogs that underwent bilateral
TPLOs during separate anesthetic episodes. Body
weight, surgery time, whether a meniscal release or
meniscectomy was performed, and extent of cruciate
ligament damage were not associated with whether
complications occurred. One hundred forty-one of
151 (93%) owners who responded to the questionnaire
were satisfied with the outcome of the surgery.
Assessments of outcome were not significantly different
between owners of dogs that had complications
and owners of dogs that did not.
Conclusions and Clinical Relevance—Results indicated
that complications developed in approximately 25%
of dogs undergoing TPLO for treatment of a cranial cruciate
ligament injury but that most complications
responded to appropriate treatment, and development
of complications did not affect owner assessments of
outcome. There was a higher incidence of complications
when bilateral TPLOs were performed during a
single anesthetic episode. (J Am Vet Med Assoc 2003;
Objective—To determine whether short-term amitriptyline
administration would be efficacious in the treatment
of acute, nonobstructive, idiopathic lower urinary tract
disease in cats.
Design—Randomized controlled trial.
Animals—31 untreated male and female cats with acute,
nonobstructive, idiopathic lower urinary tract disease.
Procedures—Cats were treated with amitriptyline (5
mg/d; n = 16) or a placebo (15) for 7 days and monitored
for pollakiuria, hematuria, and adverse events.
Cats were reexamined 1 month after treatment, and
owners were interviewed by telephone 6, 12, and 24
months after treatment.
Results—2 amitriptyline-treated cats were excluded
from analyses because of acquired urinary tract infection.
Clinical signs resolved by day 8 in 8 amitriptylinetreated
and 10 control cats. There were no apparent differences
in likelihood or rate of recovery from pollakiuria
or hematuria between groups. Overall, clinical signs
recurred significantly faster and more frequently in
amitriptyline-treated than control cats. However, after
excluding recurrences within 21 days of treatment, risk
of recurrence was similar in both groups. Increasing age
was significantly associated with increased likelihood
and rate of recovery from hematuria and with decreased
risk of recurrence of signs.
Conclusions and Clinical Relevance—Results suggest
that short-term amitriptyline treatment has no
benefit in terms of resolution of pollakiuria and hematuria
in cats with idiopathic lower urinary tract disease
and may be associated with an increased risk of
recurrence. (J Am Vet Med Assoc 2003:222:749–758)
Objective—To compare degree of viremia and disease
manifestations in calves with type-I and -II
bovine viral diarrhea virus (BVDV) infection.
Procedure—Colostrum-deprived calves obtained
immediately after birth were assigned to 1 control
and 3 treatment groups (4 calves/group). Calves in
treatment groups were inoculated (day 0) by
intranasal instillation of 107 median tissue culture
infective dose BVDV 890 (type II), BVDV 7937 (type
II), or BVDV TGAN (type I). Blood cell counts and virus
isolation from serum and leukocytes were performed
daily, whereas degree of viremia was determined
immediately before and 4, 6, 8, and 12 days after
inoculation. Calves were euthanatized on day 12, and
pathologic, virologic, and immunohistochemical
examinations were performed.
Results—Type-II BVDV 890 induced the highest
degree of viremia, and type-I BVDV TGAN induced
the lowest. Virus was isolated more frequently and
for a longer duration in calves inoculated with BVDV
890. A parallel relationship between degree of viremia
and rectal temperature and an inverse relationship
between degree of viremia and blood cell counts was
observed. Pathologic and immunohistochemical
examinations revealed more pronounced lesions and
more extensive distribution of viral antigen in calves
inoculated with type-II BVDV.
Conclusions and Clinical Relevance—Degree of
viremia induced during BVDV infection is associated
with severity of clinical disease. Isolates of BVDV that
induce a high degree of viremia may be more capable
of inducing clinical signs of disease. Strategies (eg,
vaccination) that reduce viremia may control clinical
signs of acute infection with BVDV. (Am J Vet Res