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Abstract

Objective—To compare the diagnostic performance of a point-of-care (POC) analyzer with that of established methods for the measurement of plasma IgG, total protein, and albumin concentrations in neonatal foals.

Design—Evaluation study.

Animals—100 neonatal foals < 7 days of age.

Procedures—Plasma IgG, total protein, and albumin concentrations were measured with a POC analyzer via an immunoturbidimetric method. Corresponding measurements of plasma IgG, total protein, and albumin concentrations were measured by means of automated biochemical analyzers via automated immunoturbidimetric, biuret, and bromocresol green dye–binding assays, respectively (standard laboratory methods).

Results—The sensitivity and specificity of the POC analyzer for detection of failure of passive transfer of immunity (FPTI) in foals were 80.7% and 100%, respectively, when FPTI was defined as a plasma IgG concentration < 400 mg/dL and were 75.9% and 100%, respectively, when FPTI was defined as a plasma IgG concentration < 800 mg/dL. The POC analyzer overestimated plasma albumin concentrations and, to a lesser extent, plasma total protein concentrations, compared with values determined with the standard laboratory methods.

Conclusions and Clinical Relevance—Results suggested the POC analyzer was acceptable for determination of plasma IgG and total protein concentrations in ill foals. The POC analyzer overestimated plasma albumin concentration such that its use was clinically unacceptable for the determination of that concentration. The POC analyzer provided timely measurements of plasma IgG concentrations, which is necessary information for the assessment of passive transfer of maternal antibodies to neonatal foals.

Restricted access
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine clinical characteristics, clinicopathologic data, and bacterial culture and antimicrobial susceptibility results associated with septic arthritis in foals ≤ 180 days old.

Design—Retrospective case series.

Animals—83 foals with septic arthritis.

Procedures—Medical records at 2 teaching hospitals between 1998 and 2013 were searched to identify those for foals ≤ 180 days old with confirmed infection of ≥ 1 synovial structure. Data extracted from the records included signalment, clinicopathologic information, bacteriologic culture and antimicrobial susceptibility results, and outcome. Data were analyzed for all foals as a single population and for foals stratified into 3 age groups (≤ 7 days, 8 to 30 days, and 31 to 180 days).

Results—Mean ± SD age of all foals was 18.2 ± 25 days (range, 0 to 180 days). The median number of joints affected per foal was 2 (range, 1 to 10 joints). Forty-seven of 83 (56.6%) foals survived to discharge from the hospital. Seventy antemortem synovial fluid samples underwent bacteriologic culture, of which 60 (85.7%) yielded growth. Of the 72 bacterial isolates identified, 45 (62.5%) were gram negative and 27 (375%) were gram positive. Survival rate was positively associated with plasma fibrinogen concentration and negatively associated with number of affected joints.

Conclusions and Clinical Relevance—Results indicated the frequency with which certain bacterial agents were isolated from septic joints, which may be beneficial for the empirical treatment of septic arthritis in foals. Also, the positive association between survival rate and plasma fibrinogen concentration may have prognostic value in a clinical setting.

Restricted access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate differences in response to ID injection of histamine, phytohemagglutinin (PHA), and Aspergillus organisms between clinically normal horses and horses with recurrent airway obstruction (RAO).

Animals—5 healthy adult horses and 5 adult horses with RAO.

Procedure—Intradermal testing (IDT) was performed on the neck with 2 positive control substances (histamine and PHA) and a mixture comprising 5 Aspergillus species. Four concentrations of each test substance plus a negative control substance were used. Equal volumes (0.1 mL) of each test substance were prepared to yield 15 syringes ([4 concentrations of each test substance plus 1 negative control substance] times 3 test substances) for each side of each horse (ie, 30 syringes/horse). Intradermal injections were administered; diameter of wheals was recorded 0.5, 4, and 24 hours after injection.

Results—Hypersensitive responses to ID injection of histamine were detected 0.5 hours after injection, and a delay in wheal formation after ID injection of Aspergillus mixture 24 hours after injection was detected in RAO-affected horses but was not observed in clinically normal horses. No differences were detected between the 2 groups after ID injection of PHA.

Conclusions and Clinical Relevance—RAO-affected horses are hypersensitive to histamine, suggesting that RAO is associated with a heightened vascular response to histamine. Higher concentrations of Aspergillus mixture may be needed to detect horses that are sensitive to this group of antigens. Wheal reactions to Aspergillus may be a delayed response, suggesting that IDT results should be evaluated 0.5, 4, and 24 hours after ID injection. (Am J Vet Res2005;66:1348–1355)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the precision of intradermal testing (IDT) in horses.

Animals—12 healthy adult horses.

Procedure—IDT was performed on the neck of each horse by use of 2 positive control substances (histamine and phytohemagglutinin [PHA]) and a negative control substance. An equal volume (0.1 mL) for each injection was prepared to yield a total of 20 syringes ([4 concentrations of each positive control substance plus 1 negative control substance] times 2 positive control substances times 2 duplicative tests) for each side of the neck. Both sides of the neck were used for IDT; therefore, 40 syringes were prepared for each horse. Hair was clipped on both sides of the neck, and ID injections were performed. Diameter of the skin wheals was recorded 0.5, 4, and 24 hours after ID injection.

Results—Intra- and interhorse skin reactions to ID injection of histamine and PHA resulted in wheals of uniform size at 0.5 and 4 hours, respectively. Significant intra- and interhorse variation was detected in wheals caused by PHA at 24 hours.

Conclusions and Clinical Relevance—ID injection of histamine and PHA caused repeatable and precise results at 0.5 and 4 hours, respectively. Concentrations of 0.005 mg of histamine/mL and 0.1 mg of PHA/mL are recommended for use as positive control substances for IDT in horses. This information suggests that consistent wheal size is evident for ID injection of control substances, and variation in wheals in response to ID injection of test antigens results from a horse's immune response to specific antigens. (Am J Vet Res 2005;66:1341–1347)

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To assess multiple central venous and arterial blood variables that alone or in conjunction with one another reflect global oxygenation status in healthy neonatal foals.

ANIMALS 11 healthy neonatal foals.

PROCEDURES Central venous and arterial blood samples were collected from healthy neonatal foals at 12, 24, 36, 48, 72, and 96 hours after birth. Variables measured from central venous and arterial blood samples included oxygen saturation of hemoglobin, partial pressure of oxygen, lactate concentration, partial pressure of carbon dioxide, and pH. Calculated variables included venous-to-arterial carbon dioxide gap, estimated oxygen extraction ratio, ratio of partial pressure of oxygen in arterial blood to the fraction of inspired oxygen, bicarbonate concentration, base excess, and blood oxygen content.

RESULTS Significant differences between arterial and central venous blood obtained from neonatal foals were detected for several variables, particularly partial pressure of oxygen, oxygen saturation of hemoglobin, and oxygen content. In addition, the partial pressure of carbon dioxide in central venous blood samples was significantly higher than the value for corresponding arterial blood samples. Several temporal differences were detected for other variables.

CONCLUSIONS AND CLINICAL RELEVANCE Results of this study provided information about several variables that reflect global oxygenation in healthy neonatal foals. Values for these variables in healthy foals can allow for comparison with values for critically ill foals in future studies. Comparison of these variables between healthy and ill foals may aid in treatment decisions and prognosis of clinical outcome for critically ill foals.

Full access
in American Journal of Veterinary Research
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE

To assess whether the combination of hyaluronan, sodium chondroitin sul-fate, and N-acetyl-d-glucosamine (HCSG) lubricates articular cartilage in vitro and modulates joint lubrication in vivo.

ANIMALS

16 healthy adult horses.

PROCEDURES

The effects of HCSG injections on SF lubricant properties and joint health, immediately after injury and 2 weeks later, were analyzed by use an equine osteochondral fracture model of post-traumatic osteoarthritis (OA). Middle carpal joints of adult horses were randomly assigned to 1 of 4 surgical treatment groups as follows: normal nonsurgical group (n = 8), normal sham-surgical group (8), OA-induced surgical group with HCSG injection (8), or OA-induced surgical group with saline (0.9% NaCl) solution injection (8). Synovial fluid was aspirated periodically and analyzed for boundary lubrication function and lubricant molecules. At 17 days, joints were screened for gross pathological changes.

RESULTS

Induction of OA led to an impairment of SF lubrication function and diminished hyaluronan concentration in a time-dependent manner following surgery, with HCSG injection lessening these effects. Certain friction coefficients approached those of unaffected normal equine SF. Induction of OA also caused synovial hemorrhage at 17 days, which was lower in joints treated with HCSG.

CONCLUSIONS AND CLINICAL RELEVANCE

After induction of OA, equine SF lubricant function was impaired. Hyaluronan-sodium chondroitin sulfate–N-acetyl-d-glucosamine injection restored lubricant properties at certain time points and reduced pathological joint changes.

Full access
in American Journal of Veterinary Research