Objective—To determine glycosaminoglycan (GAG)
concentration and immunohistochemical staining
characteristics of type-I, -II, and -X collagen from cartilage
affected by osteochondritis dissecans (OCD) in
Animals—31 dogs with OCD and 11 clinically normal
Procedure—Cartilage samples were evaluated
microscopically, and GAG content was determined.
Immunohistochemical staining was performed for
type-I, -II, and -X collagen. Sections were subjectively
evaluated for location and intensity of staining.
Results—Cartilage affected by OCD had a variety of
pathologic changes and significantly lower GAG concentrations
than did normal cartilage. Normal cartilage
had no detectable type-I collagen. For dogs < 9
months of age, cartilage affected by OCD had significantly
more type-I collagen but significantly less type-
X collagen than did control cartilage. For dogs > 12
months of age, cartilage affected by OCD contained
significantly more type-I collagen than did control cartilage.
There was a significant negative correlation
between immunoreactivity of type-I collagen and that
of type-II and -X collagen. A significant positive correlation
was found between immunoreactivity of type-II
and -X collagen.
Conclusions and Clinical Relevance—Cartilage
affected by OCD contains less GAG, more type-I collagen,
and less type-X collagen, compared with normal
cartilage. A direct correlation between these
changes and the etiopathogenesis of OCD was not
established. (Am J Vet Res 2001;62:876–881)
Objective—To assess IgE response and cytokine gene expressions in pulmonary lymph collected from bovine respiratory syncytial virus (BRSV)-infected calves after ovalbumin inhalation.
Animals—Thirteen 7- to 8-week-old calves.
Procedures—The efferent lymphatic duct of the caudal mediastinal lymph node of each calf was cannulated 3 or 4 days before experiment commencement. Calves were inoculated (day 0) with BRSV (n = 7) or BRSV-free tissue culture medium (mock exposure; 6) via aerosolization and exposed to aerosolized ovalbumin on days 1 through 6 and day 15. An efferent lymph sample was collected daily from each calf on days −1 through 16; CD4+ and CD8+ T lymphocyte subsets in lymph samples were enumerated with a fluorescence-activated cell scanner. Expressions of several cytokines by efferent lymphocytes and lymph ovalbumin-specific IgE concentration were measured. Each calf was euthanized on day 16 and then necropsied for evaluation of lungs.
Results—Mean fold increase in ovalbumin-specific IgE concentration was greater in BRSV-infected calves than in mock-infected calves. At various time points from days 4 through 10, percentages of T lymphocyte subsets and CD4+:CD8+ T lymphocyte ratios differed between BRSV-infected calves and day −1 values or from values in mock-infected calves. On days 3 through 5, IL-4 and IL-13 gene expressions in BRSV-infected calves were increased, compared with expressions in mock-infected calves. Lung lesions were consistent with antigen exposure.
Conclusions and Clinical Relevance—In response to the inhalation of aerosolized ovalbumin, BRSV infection in calves appeared to facilitate induction of a T helper 2 cell response and ovalbumin-specific IgE production.
Objective—To study the local immune response of
calves to bovine respiratory syncytial virus (BRSV)
infection with emphasis on IgE production and
cytokine gene expression in pulmonary lymph.
Animals—Twelve 6- to 8-week-old Holstein bull
calves. Six similar control calves were mock infected
to obtain control data.
Procedure—Lymphatic cannulation surgery was performed
on 12 calves to create a long-term thoracic
lymph fistula draining to the exterior. Cannulated
calves were exposed to virulent BRSV by aerosol.
Lymph fluid collected daily was assayed for BRSV and
isotype-specific IgE antibody, total IgG, IgA, IgM, and
protein concentrations. Interleukin-4 (IL-4), interleukin-
2 (IL-2), and interferon-γ were semi-quantitated
by reverse transcription-polymerase chain reaction
(RT-PCR). Cell counts and fluorescence-activated cell
scanner (FACSCAN) analysis of T-cell subsets were
performed on lymph cells.
Results—Calves had clinical signs of respiratory tract
disease during days 5 to 10 after infection and shed
virus. Bovine respiratory syncytial virus-specific IgE in
infected calves was significantly increased over baseline
on day 9 after infection. Mean virus-specific IgE
concentrations strongly correlated with increases in
severity of clinical disease (r = 0.903). Expression of
IL-2, IL-4, and interferon-γ was variably present in
infected and control calves, with IL-4 expression
most consistent during early infection.
Conclusions and Clinical Relevance—Infection with
BRSV was associated with production of BRSV-specific
IgE, and IL-4 message was commonly found in
lymph cells of infected calves. This finding supports
the concept that BRSV-induced pathophysiology
involves a T helper cell type-2 response. Effective
therapeutic and prophylactic strategies could, therefore,
be developed using immunomodulation to shift
the immune response more toward a T helper cell
type-1 response. (Am J Vet Res 2000;61:291–298)
Case Description—A healthy 6-year-old 28.5-kg (62.7-lb) spayed female Boxer undergoing surgical repair of a ruptured cranial cruciate ligament was inadvertently administered an overdose of morphine (1.3 mg/kg [0.59 mg/lb]) via subarachnoid injection.
Clinical Findings—50 minutes after administration of the overdose, mild multifocal myoclonic contractions became apparent at the level of the tail; the contractions migrated cranially and progressively increased in intensity and frequency during completion of the surgery.
Treatment and Outcome—The myoclonic contractions were refractory to treatment with midazolam, naloxone, phenobarbital, and pentobarbital; only atracurium (0.1 mg/kg [0.045 mg/lb], IV) was effective in controlling the movements. The dog developed hypertension, dysphoria, hyperthermia, and hypercapnia. The dog remained anesthetized and ventilated mechanically; treatments included continuous rate IV infusions of propofol (1 mg/kg/h [0.45 mg/lb/h]), diazepam (0.25 mg/kg/h [0.11 mg/lb/h]), atracurium (0.1 to 0.3 mg/kg/h [0.045 to 0.14 mg/lb/h]), and naloxone (0.02 mg/kg/h [0.009 mg/lb/h]). Twenty-two hours after the overdose, the myoclonus was no longer present, and the dog was able to ventilate without mechanical assistance. The dog remained sedated until 60 hours after the overdose, at which time its mentation improved, including recognition of caregivers and response to voice commands. No neurologic abnormalities were detectable at discharge (approx 68 hours after the overdose) or at a recheck evaluation 1 week later.
Clinical Relevance—Although intrathecal administration of an overdose of morphine can be associated with major and potentially fatal complications, it is possible that affected dogs can completely recover with immediate treatment and extensive supportive care.
Objective—To characterize rib, intrathoracic, and concurrent
orthopedic injuries, and prognosis associated
with traumatic rib fracture in cats.
Procedure—Medical records from January 1980 to
August 1998 were examined for cats with traumatic
rib fracture. Signalment, cause of trauma, interval
from trauma to evaluation at a veterinary teaching
hospital, referral status and date, method of diagnosis,
duration of hospitalization, number and location of
rib fractures, presence of flail chest, costal cartilage
involvement, intrathoracic and concurrent orthopedic
injury, and clinical outcome were reviewed.
Results—Median age was 3 years. Twenty-five
(58%) cats with reported cause of trauma were
injured by interaction with another animal. Fortyseven
(78%) cats that were treated survived. Cats
that died had a median duration of hospitalization of
< 1 day. Ten (13%) cats had flail chest. Sixty-five
(87%) cats had intrathoracic injury (median, 2
injuries). Nine (100%) cats without detected intrathoracic
injury that were treated survived. Thirty-five
(47%) cats had concurrent orthopedic injury. Cats
with flail chest, pleural effusion, or diaphragmatic
hernia were significantly more likely to die than cats
without each injury.
Conclusions and Clinical Relevance—Traumatic rib
fracture in cats is associated with intrathoracic and
concurrent orthopedic injury. Aggressive treatment of
cats with traumatic rib fracture is warranted, because
the prognosis is generally favorable. Diagnosis and
treatment of intrathoracic injury associated with traumatic
rib fracture in cats should precede management
of concurrent orthopedic injury. ( J Am Vet Med
Objective—To determine the distribution for limbs and bones in horses with fractures of the proximal sesamoid bones and relationships with findings on palmarodorsal radiographic images.
Sample Population—Proximal sesamoid bones obtained from both forelimbs of cadavers of 328 racing Thoroughbreds.
Procedure—Osteophytes; large vascular channels; and fracture location, orientation, configuration, and margin distinctness were categorized by use of high-detail contact palmarodorsal radiographs. Distributions of findings were determined. Relationships between radiographic findings and fracture characteristics were examined by use of χ2 and logistic regression techniques.
Results—Fractures were detected in 136 (41.5%) horses. Biaxial fractures were evident in 109 (80%) horses with a fracture. Osteophytes and large vascular channels were evident in 266 (81%) and 325 (99%) horses, respectively. Medial bones typically had complete transverse or split transverse simple fractures, indistinct fracture margins, > 1 vascular channel that was > 1 mm in width, and osteophytes in abaxial wing and basilar middle or basilar abaxial locations. Lateral bones typically had an oblique fracture and distinct fracture margins. Odds of proximal sesamoid bone fracture were approximately 2 to 5 times higher in bones without radiographic evidence of osteophytes or large vascular channels, respectively.
Conclusions and Clinical Relevance—Biaxial fractures of proximal sesamoid bones were common in cadavers of racing Thoroughbreds. Differences between medial and lateral bones for characteristics associated with fracture may relate to differences in fracture pathogeneses for these bones. Osteophytes and vascular channels were common findings; however, fractures were less likely to occur in bones with these features.