Search Results
You are looking at 1 - 8 of 8 items for
- Author or Editor: Rick D. Howard x
- Refine by Access: All Content x
Abstract
Objectives—To evaluate the effects of equine recombinant interleukin-1α (rEqIL-1α) and recombinant interleukin- 1β (rEqIL-1β) on proteoglycan metabolism and prostaglandin E2 (PGE2) synthesis by equine articular chondrocytes in explant culture.
Sample Population—Near full-thickness articular cartilage explants (approx 50 mg) harvested from stifle joints of a 3-year-old and a 5-year-old horse.
Procedure—Expression constructs containing cDNA sequences encoding EqIL-1α and EqIL-1β were generated, prokaryotically expressed, and the recombinant protein purified. Near full-thickness articular cartilage explants (approx 50 mg) harvested from stifle joints of a 3-year-old and a 5-year-old horse were separately randomized to receive rEqIL- 1α or rEqIL-1β treatments (0 to 500 ng/ml). Proteoglycan release was evaluated by 1,9-dimethylmethylene blue spectrophotometric analysis of explant media glycosaminoglycan (GAG) concentration and release of 35S-sulfate-labeled GAG to explant media. Proteoglycan synthesis was assessed by quantification of 35S-sulfate incorporation into proteoglycan. Explant media PGE2 concentrations were evaluated using a PGE2-specific enzyme-linked immunoassay. Data were collected at 48-hour intervals and normalized by DNA content.
Results—Proteoglycan release was induced by rEqIL- 1α and rEqIL-1β at concentrations ≥ 0.1 ng/ml, with 38 to 76% and 88 to 98% of total GAG released by 4 and 6 days, respectively. Inhibition of proteoglycan synthesis (42 to 64%) was observed at IL-1 concentrations ≥ 0.1 ng/ml at 2 and 4 days. Increased PGE2 concentrations were observed at IL-1 concentrations ≥ 0.1 ng/ml at 2 and 4 days.
Conclusions and Clinical Relevance—The rEqIL-1 induced potent concentration-dependent derangement of equine chondrocyte metabolism in vitro . These findings suggest this model may be suitable for the in vitro study of the pathogenesis and treatment of joint disease in horses. (Am J Vet Res 2002; 63:551–558)
Abstract
Objectives
To clone equine interleukin 1 receptor antagonist (IL-1 ra) and determine its full-length cDNA sequence.
Procedure
A cDNA library derived from lipopolysaccharide-stimulated equine monocytes was screened by means of plaque hybridization to radiolabeled equine IL-1ra DNA probes generated by means of the polymerase chain reaction. The cDNA nucleotide sequence for equine IL-1ra was determined by use of the dideoxy chain termination technique, analyzed by use of computer software for sequence characteristics, and compared with sequences reported for IL-1ra of other species.
Results
The cDNA for equine IL-1ra was 1,614 base pairs in length with an ORF encoding a peptide of 177 amino acids with a predicted molecular mass of 20.427 kd. Similarity between the amino acid sequence of equine IL-1ra and sequences for human, murine, rat, and lapine IL-1ra was 76%. Similarity between sequence for equine IL-1ra and sequences for equine interleukin-1α and equine interleukin-1ß were 22.6 and 24.6%, respectively.
Conclusion
Comparison of the sequence for equine IL-1ra with sequences for IL-1ra of other species indicated a high degree of conservation.
Clinical Relevance
Results establish a basis for studying the roles of interleukin-1 in healthy and diseased joints in horses. (Am J Vet Res 1998;59:712-716)
Abstract
Objectives
To clone equine interleukin 1α (IL-1α) and equine interleukin 1β (IL-1β) and determine their full-length cDNA sequences.
Procedure
The mRNA isolated from lipopolysaccharide-stimulated cultured equine monocytes was reverse transcribed, and a cDNA library was constructed in a λ phage. The cDNA library was screened by means of plaque hybridization with radiolabeled human IL-1α and IL-1ß cDNA probes. The cDNA nucleotide sequences for equine IL-1α and equine IL-1β were determined by use of the dideoxy chain termination technique. The cDNA sequences were analyzed, using computer software, for sequence characteristics and compared with sequences reported for other species.
Results
The cDNA for equine IL-1α was 1,728 base pairs in length with an ORF encoding a peptide of 270 amino acids with a predicted molecular mass of 30.823 kd. The cDNA for equine IL-1β was 1,473 base pairs in length with an ORF encoding a peptide of 268 amino acids with a predicted molecular mass of 30.342 kd. Similarity between amino acid sequence of equine IL- 1α and sequences for IL-1 α of other species ranged from 62.5 to 82.2%; similarity between amino acid sequence of equine IL-1ß and sequences for IL-1β of other species ranged from 62.5 to 66.4%. Similarity between amino acid sequences of equine IL-1α and equine IL-1β was 26%.
Conclusions and Clinical Relevance
Results establish a basis for studying the roles of interleukin 1 in healthy and diseased joints in horses. (Am J Vet Res 1998;59:704-711)
Abstract
Objective—To determine clinical outcome following intrathecal injection of the podotrochlear (navicular) bursa for signs of foot pain in horses evaluated via magnetic resonance imaging (MRI) and evaluate efficacy of corticosteroids administered with or without hyaluronate.
Design—Retrospective case series.
Animals—23 horses.
Procedures—Data collected included signalment, history, intended use, duration and severity of lameness, results of diagnostic anesthesia, radiographic abnormalities, MRI abnormalities, and outcomes for return to use.
Results—MRI was conducted on 23 horses with lameness localized to the foot. Thirteen horses had bilateral forelimb lameness, and 10 had unilateral forelimb lameness. Mean duration of lameness was 10.5 months. Seventeen of 23 (74%) horses had excellent outcomes and returned to intended use within 2 to 4 weeks after navicular bursa injection. Hyaluronate treatment was not associated with outcome; however, horses receiving < 10 mg of trimacinolone had significantly worse outcomes than those treated with hyaluronate. Among horses with excellent outcomes, mean duration of soundness was 7.3 months. Seven of 8 horses with erosive lesions of the flexor surface of the distal sesamoid (navicular) bone diagnosed via MRI had a poor outcome. Horses with navicular bursitis responded optimally to injection, compared with horses with other problems.
Conclusions and Clinical Relevance—Results suggested that intrathecal injection of corticosteroid in horses with erosions of the flexor surface of the navicular bone associated with deep digital flexor tendon adhesions yielded a poor response. Treatment of horses with navicular bursitis via injection of the navicular bursa should be highly effective in alleviating lameness.
Abstract
Objective
To estimate sensitivity and accuracy of subjective evaluation of mild lameness in horses during treadmill locomotion and to correlate subjective evaluation with kinematic analysis.
Animals
19 lame and 5 clinically normal horses.
Procedure
Lameness was evaluated by subjective score and kinematic analysis before and after palmar digital nerve block (PDNB). Evaluations were made by 6 clinicians and 7 interns or residents. Within- and between-observer agreement analyses (κ values) were calculated and compared, using a Student’s t-test. Pearson’s product-moment correlation coefficients were calculated between clinician’s change in score and the change in kinematic variables after PDNB.
Results
Within-observer agreement was within the range expected for conditions of moderate diagnostic difficulty. Within-observer agreement was higher for clinicians than for interns or residents. Between-observer agreement was acceptable for scores within 1 value of each other. Between-observer agreement of change in lameness score after PDNB was poor. When kinematic variables were ranked with each clinician’s subjective change in score, only 2 were among the top 3 for the majority of clinicians. Asymmetry of vertical head movement between contralateral forelimb stance phases and the point of maximum hoof height during swing decreased as lameness subjectively improved.
Conclusion
Mild lameness may be difficult to evaluate during treadmill locomotion. Although clinicians were more repeatable in their subjective evaluation of lameness than interns or residents, they were not more reliable at detecting the true state of lameness.
Clinical Relevance
Lack of agreement between clinician scoring of mild lameness emphasizes the need to use more objective measures for quantifying lameness. (Am J Vet Res 1998;59:1370–1377)
