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- Author or Editor: James D. Lillich x
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Abstract
Objective—To determine clinical findings in and outcome of horses with fractures of the second or fourth metacarpal or metatarsal bone that underwent segmental ostectomy, leaving the proximal and distal portions of the bone undisturbed.
Design—Retrospective case series.
Animals—17 horses.
Procedures—Medical records were reviewed, and information on signalment, affected bone, lesion type, surgical procedure, amount of bone removed, and surgical and postsurgical complications was obtained. Follow-up information was obtained through telephone conversations with owners, trainers, and referring veterinarians.
Results—One horse had a fracture involving the distal third of the second metacarpal bone; 13 had fractures involving the middle third of the second metacarpal bone (n = 4), fourth metacarpal bone (5), or fourth metatarsal bone (4); and 3 had fractures involving the proximal third of the second (2) or fourth (1) metacarpal bone. Affected portions of the bones were surgically resected, leaving the proximal and distal portions undisturbed. All horses returned to previous performance levels without evidence of lameness. Cosmetic results were good to excellent.
Conclusions and Clinical Relevance—Results suggest that horses with a complicated injury of the proximal, middle, or distal portion of the second or fourth metacarpal or metatarsal bone may be successfully treated by means of segmental ostectomy of the abnormal portion of the bone. (J Am Vet Med Assoc 2004;224:271–274)
Abstract
Objective—To determine hyaluronan concentrations in peritoneal fluid from healthy horses and horses with sudden signs of severe abdominal pain and to identify the cellular sources of hyaluronan within the peritoneal cavity.
Animals—7 client-owned horses that were evaluated for sudden signs of severe abdominal pain, 6 healthy teaching horses, and 13 euthanized horses (11 with no abdominal disease and 2 that had undergone abdominal surgery 2 weeks previously for a different study).
Procedures—Abdominal fluid was collected from the client-owned and teaching horses. Hyaluronan concentrations were determined with an ELISA. Equine mesothelial cells were aseptically harvested from euthanized horses immediately after euthanasia, cultured, and processed for western blot immunoassays to detect expression of the following mesothelial cell markers: cytokeratins 8 and 18, vimentin, calretinin, mesothelin, and CD44. A reverse transcriptase–PCR assay was used to detect genetic expression of hyaluronan synthase-2 (HAS-2) from cultured and native equine tissue.
Results—The mean ± SD abdominal hyaluronan concentration in peritoneal fluid from horses with signs of abdominal pain (1,203.3 ± 46.3 ng/mL) was significantly greater than that in healthy horses (228.4 ± 167.3 ng/mL). Harvested cells were maintained, and immunoblotting analyses confirmed expression of the mesothelial markers. Gene expression of HAS-2 from cultured mesothelial cells and fibroblasts was confirmed.
Conclusions and Clinical Relevance—Peritoneal hyaluronan concentration was much higher in horses with severe abdominal pain than in healthy horses. Cultured equine mesothelial cells and fibroblasts can produce hyaluronan through HAS-2. Future investigation should focus on establishing the effect of exogenous hyaluronan administration on mesothelial cell function in horses with abdominal disease.
Abstract
Objective—To determine the response of cortical bone to a multicomponent and nanostructural polymeric matrix as a drug delivery system for enhancing bone healing.
Animals—20 healthy adult crossbred goats.
Procedures—A 3.5-mm-diameter unicortical defect was created in each tibia (day 0), and goats (4 goats/group) were treated as follows: not treated (control group), grafted with the matrix, grafted with antimicrobial (tigecycline and tobramycin)–impregnated matrix, grafted with recombinant human bone morphogenetic protein type 2 (rhBMP-2)–impregnated matrix, or grafted with antimicrobial- and rhBMP-2–impregnated matrix. Elution kinetics of antimicrobials was monitored through plasma concentrations. Bone response was assessed with radiographic scoring (days 1 and 30) and dual-energy x-ray absorptiometry (days 1, 14, and 30). Goats were euthanized on day 30, and histomorphologic analysis was performed. Categorical variables were analyzed with a generalized linear model, and continuous variables were analyzed with an ANOVA.
Results—Plasma antimicrobial concentrations indicated continued release throughout the study. Radiography and dual-energy x-ray absorptiometry did not reveal significant differences among treatments on day 30. Periosteal reactions were significantly greater surrounding bone defects grafted with rhBMP-2–impregnated matrix than those not treated or grafted with matrix or with antimicrobial-impregnated matrix; periosteal reactions were similar in bone defects grafted with rhBMP-2–impregnated matrix and antimicrobial- and rhBMP-2–impregnated matrix.
Conclusions and Clinical Relevance—The matrix served as an antimicrobial delivery system and stimulated bone proliferation when rhBMP-2 was present. Antimicrobial and rhBMP-2 can be used concurrently, but the presence of antimicrobials may affect the performance of rhBMP-2.
Abstract
Objective—To determine microradiographic appearance, bone histomorphometry, and mineral density of the long bones of the metacarpophalangeal joint in horses after immobilization followed by remobilization.
Animals—5 healthy horses.
Procedure—One forelimb of each horse was immobilized in a fiberglass cast for 7 weeks, followed by 8 weeks of increasing exercise. Calcein and oxytetracycline were administered IV during the immobilization and exercise phases, respectively, for bone labeling and analysis after euthanasia. Sagittal sections of metacarpal bones and proximal phalanges were examined via radiography, dual energy x-ray absorptiometry, histomorphometry, and bone label analysis.
Results—Radiography revealed loss of bone mineral opacity in the subarticular regions of the immobilized metacarpal bones and phalanges and subchondral lesions in metacarpal bones in 2 horses. In phalanges, a significant decrease in subarticular volumetric bone mineral density was detected. There was significantly less bone volume and calcein-labeled bone surface and more vascular volume and oxytetracycline-labeled bone surface in immobilized phalanges, compared with contralateral phalanges.
Conclusions and Clinical Relevance—Eight weeks of exercise after single-limb immobilization is insufficient for recovery of volumetric bone mineral density. During immobilization and remobilization, the subchondral and trabecular bone appear to be actively remodeling. (Am J Vet Res 2002;63:276–281)
Abstract
Objective—To evaluate clinical effects of immobilization followed by remobilization and exercise on the metacarpophalangeal joint (MPJ) in horses.
Animals—5 healthy horses.
Procedure—After lameness, radiographic, and force plate examinations to determine musculoskeletal health, 1 forelimb of each horse was immobilized in a fiberglass cast for 7 weeks, followed by cast removal and increasing amounts of exercise, beginning with hand-walking and ending with treadmill exercise. Lameness examination, arthrocentesis of both MPJ, single-emulsion radiographic examination, nuclear scintigraphic examination, ground-reaction force-plate analysis, and computed tomographic examination were done at various times during the study.
Results—All horses were lame in the immobilized MPJ after cast removal; lameness improved slightly with exercise. Force plate analysis revealed a significant difference in peak forces between immobilized and contralateral limbs 2 weeks after cast removal. Range of motion of the immobilized MPJ was significantly decreased, and joint circumference was significantly increased, compared with baseline values, during the exercise period. Osteopenia was subjectively detected in the immobilized limbs. Significant increase in the uptake of radionucleotide within bones of the immobilized MPJ after cast removal and at the end of the study were detected. Loss of mineral opacity, increased vascular channels in the subchondral bone, and thickening within the soft tissues of the immobilized MPJ were detected.
Conclusions and Clinical Relevance—Results indicate that 8 weeks of enforced exercise after 7 weeks of joint immobilization did not restore joint function or values for various joint measurements determined prior to immobilization. (Am J Vet Res 2002;63:282–288)
Abstract
Objective—To determine whether ether-a-go-go (ERG) potassium channels are expressed in equine gastrointestinal smooth muscle, whether ERG channel antagonists affect jejunal muscle contraction in vitro, and whether plasma cisapride concentrations in horses administered treatment for postoperative ileus (POI) are consistent with ERG channels as drug targets.
Sample Population—Samples of intestinal smooth muscle obtained from 8 horses free of gastrointestinal tract disease and plasma samples obtained from 3 horses administered cisapride for treatment of POI.
Procedure—Membranes were prepared from the seromuscular layer of the duodenum, jejunum, ileum, cecum, large colon, and small colon. Immunoblotting was used to identify the ERG channel protein. Isolated jejunal muscle strips were used for isometric stress response to ERG channel blockers that included E-4031, MK-499, clofilium, and cisapride. Plasma concentrations of cisapride were determined in 3 horses administered cisapride for treatment of POI after small intestinal surgery.
Results—Immunoblotting identified ERG protein in all analyzed segments of the intestinal tract in all horses. The selective ERG antagonist E-4031 caused a concentration- dependent increase in jejunal contraction. Clofilium, MK-499, and cisapride also increased jejunal contraction at concentrations consistent with ERG channel block; effects of E-4031 and cisapride were not additive. Peak plasma cisapride concentrations in treated horses were consistent with ERG block as a mechanism of drug action.
Conclusions and Clinical Relevance—The ERG potassium channels modulate motility of intestinal muscles in horses and may be a target for drugs. This finding may influence development of new prokinetic agents and impact treatment of horses with POI. (Am J Vet Res 2003;64:267–272)
Abstract
Objective—To determine history, physical and diagnostic examination findings, medical treatment, and outcome of horses with open injuries to the digital flexor tendon sheath treated with the assistance of tenoscopy.
Design—Retrospective study.
Animals—20 horses.
Procedure—Medical records of 20 horses with open injuries to the digital flexor tendon sheath were reviewed. Signalment, history, physical and diagnostic examination results, bacteriologic culture and susceptibility testing results, surgical and medical treatments, and follow-up examination results were determined. Outcome was determined by use of telephone interview or physical examination.
Results—All horses were treated with tenoscopicassisted lavage and débridement. Eighteen horses survived, and 2 were euthanatized during treatment. All horses were either grade-4 or grade-5 lame before treatment. Ten horses returned to previous use. Four horses were considered mildly lame and in athletic use. Three horses were considered mechanically lame and are in use with reduced expectations. One horse was lost to follow-up after being sold. One horse was euthanatized for financial reasons and 1 because of complications from regional sepsis.
Conclusions and Clinical Relevance—Tenoscopy appears to be a useful modality in the treatment of open injury to the digital flexor tendon sheath in horses. Direct viewing, guided débridement, and targeted large-volume lavage are advantages obtained with intrathecal arthroscopy. Tenoscopy, when combined with antimicrobial and anti-inflammatory treatment, appears to offer a good chance of survival for affected horses. (J Am Vet Med Assoc 2002;220:1823–1827)
