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Biomedical subjects

E M Gaughan

Publications and source records attributed to E M Gaughan.

At least 19 recordsLinked to original sources

Fibrosarcoma over the tarsal groove of a 14-month-old Quarter horse.

A 14-month-old male Quarter horse was presented for evaluation of a grade 3 out of 5 (grade 0 = sound; grade 5 = non-weight bearing) right rear lameness. A firm, 8 x 16 cm mass was palpable at the caudal medial aspect of the distal tibia and proximal tarsal region of the right hind limb. A percutaneous needle aspirate contained mesenchymal cells that were moderate to large in size with single, oblong nuclei. Differential diagnoses included fibrous hyperplasia, fibroma, or well-differentiated fibrosarcoma. Excisional biopsy for both definitive diagnosis and treatment was offered and selected by the owner. A fibrosarcoma was confirmed by histological examination of the mass. One and a half years after resection signs of lameness or evidence of regrowth of the mass were not evident.

Animals↗

The effect of intra-articular methylprednisolone acetate and exercise on equine carpal subchondral and cancellous bone microhardness.

Dorsal carpal osteochondral injury is a major cause of lameness in horses undergoing high intensity training. Intra-articular corticosteroid treatment is used commonly to manage exercise-associated articular pain, but its use remains highly controversial in the equine athlete. This project, therefore, aimed to compare the mechanical properties of intra-articular MPA and diluent-treated middle carpal subchondral and cancellous bone in horses undergoing a short-term treadmill exercise programme. It was hypothesised that subchondral and cancellous bone mechanical properties are influenced by intra-articular administration of methylprednisolone acetate (MPA). Eight 2-year-old female horses had MPA or diluent administered into contralateral middle carpal joints at 14 day intervals, for a total of 4 treatments per horse. Horses underwent a standard treadmill exercise protocol until euthanasia (Day 70). Standard sites were located on the dorsal aspect of third, radial and intermediate carpal bones. Osteochondral samples from each test site were divided into subchondral bone and cancellous bone portions. These were dried, resin-embedded and gold-coated. Microhardness measurements were obtained at each test site. No significant effect of intra-articular treatment was detected. At each site, cancellous bone trabecular struts had an 18-19% higher microhardness value than the overlying subchondral bone. These findings indicate that intra-articular administration of MPA at this dose has no effect on subchondral or cancellous bone adaptation to short-term exercise and, therefore, on the propensity of carpal bones to injury. Further investigation into the calcified cartilage layer, effect of different corticosteroid preparations and diffusion of medication are required.

Animals↗

Severe complication after administration of formalin for treatment of progressive ethmoidal hematoma in a horse.

Formalin was injected into an ethmoidal hematoma in an 18-year-old Arabian gelding. Abnormal neurologic signs were observed within minutes of the injection. The horse did not respond favorably to medical treatment of the neurologic signs and was euthanatized. Postmortem examination revealed erosion and necrosis of the ventral cribriform plate, which appeared to have allowed the injected formalin to reach the rostral portion of the frontal lobe of the brain. Endoscopy and radiography had been performed prior to euthanasia, but neither delineated the cribriform lesion. Before treating large progressive ethmoidal hematomas with formalin, it may be beneficial to perform computed tomography to assess the extent of damage caused by the lesion.

Animals↗

Effects of external thermal manipulation on laminar temperature and perfusion scintigraphy of the equine digit.

AIMS: To assess the effects of external thermal manipulation on the soft-tissue and vascular perfusion of the equine digit using nuclear scintigraphy and documented tissue temperatures. METHODS: Six horses were used in a randomised crossover design. Each horse was treated with external heat (47 degrees C) or external cold (4 degrees C) applied to a digit for 30 minutes. The opposite front foot was untreated and used for control measurements. Nuclear scintigraphy was performed before, during, and after therapy to assess vascular and soft-tissue perfusion to the digit in response to therapy. Dorsal hoof wall laminar-tissue temperatures were recorded before, during, and after therapy using a thermistor. RESULTS: Treatment with topical cold therapy significantly decreased soft-tissue perfusion of the digit to 80.5% of the pre-cooled values. Conversely, the application of external heat significantly increased soft-tissue perfusion of the digit 25.1% above the pre-heated values. Vascular perfusion showed similar, but not statistically significant trends. External cold application to the digit caused a significant mean decrease in laminar-tissue temperatures of 11.6 degrees C during therapy, while external heat application to the digit caused a significant mean increase in laminar-tissue temperatures of 3.9 degrees C. CONCLUSION: The external application of heat and cold to the normal equine foot could effectively alter soft-tissue perfusion and laminar-tissue temperatures within 30 minutes of treatment. The application of hot water and ice water to the digit was a safe, well-tolerated, and economical therapy. CLINICAL RELEVANCE: Cooling the foot could decrease enzymatic reactions associated with laminitis, and warming could increase local perfusion when desired.

Journal Article↗

Arthrodesis of the proximal interphalangeal joint affected with septic arthritis in 8 horses.

Arthrodesis was performed to treat septic arthritis of the proximal interphalangeal joint of 8 horses. Records of the horses were reviewed to determine outcome and possible factors that influenced success or failure. All horses were female. Seven horses had 1 joint treated and 1 horse was treated for bilateral pelvic limb involvement. The duration of sepsis before surgery ranged from 1 to 66 days. Bone lysis and production was radiographically apparent in 7 horses before surgery. Six horses had multiple bacterial organisms cultured from bone or synovial tissues; 2 horses had single isolates identified. After aggressive curettage, arthrodesis was accomplished with 3 parallel screws in 1 horse, 2 divergent narrow dynamic compression plates in 3 horses, and a single broad dynamic compression plate in 4 horses. Casts were applied to all horses for 1 to 6 weeks. Four horses survived to successful brood mare status. Four horses were euthanized during hospitalization because of continued discomfort or complications of sepsis. Arthrodesis of the proximal interphalangeal joint affected with septic arthritis appears to be an acceptable alternative to euthanasia for some horses.

Animals↗

A retrospective analysis of left dorsal displacement of the large colon treated with phenylephrine hydrochloride and exercise in 12 horses (1996-98).

AIM: To review the outcome of cases of left dorsal displacement of the large colon (LDDLC) treated with phenylephrine HCl and mild exercise. METHODS: Physical parameters, laboratory data, ultrasonographic findings and outcome were analysed in a retrospective study of 12 horses with a confirmed diagnosis of LDDLC which were treated with phenylephrine HCl and mild exercise. RESULTS: Administration of phenylephrine HCl and mild exercise resulted in the resolution of LDDLC in 11 of 12 treated horses. One horse failed to resolve the entrapment and required surgical correction. CONCLUSION: Administration of phenylephrine HCl appears to be an effective treatment for horses with confirmed diagnosis of LDDLC presented with mild to moderate colonic distention.

Journal Article↗

Effect of furosemide on pulmonary blood flow distribution in resting and exercising horses.

We determined the spatial distribution of pulmonary blood flow (PBF) with 15-micron fluorescent-labeled microspheres during rest and exercise in five Thoroughbred horses before and 4 h after furosemide administration (0.5 mg/kg iv). The primary finding of this study was that PBF redistribution occurred from rest to exercise, both with and without furosemide. However, there was less blood flow to the dorsal portion of the lung during exercise postfurosemide compared with prefurosemide. Furosemide did alter the resting perfusion distribution by increasing the flow to the ventral regions of the lung; however, that increase in flow was abated with exercise. Other findings included 1) unchanged gas exchange and cardiac output during rest and exercise after vs. before furosemide, 2) a decrease in pulmonary arterial pressure after furosemide, 3) an increase in the slope of the relationship of PBF vs. vertical height up the lung during exercise, both with and without furosemide, and 4) a decrease in blood flow to the dorsal region of the lung at rest after furosemide. Pulmonary perfusion variability within the lung may be a function of the anatomy of the pulmonary vessels that results in a predominantly fixed spatial pattern of flow distribution.

Animals↗

Congenital dental disease of horses.

Equine congenital dental deformities are not limited merely to those presented here; however, the examples discussed offer the reader an appreciation for the range of severity and complexity that may be found in affected horses. The veterinarian is obligated to provide the best possible care for the patient and to relieve animal suffering. The lack of definitive evidence for heritability of many of these defects can place the veterinarian in an untenable position, particularly when presented with literature that proclaims or suggests without evidence that a particular condition is inherited. In such cases, the veterinarian is encouraged to counsel owners, citing substantiated medical information, and to recommend that owners make the decision to eliminate the affected animals' ability to reproduce.

Animals↗

Dental surgery in horses.

Dental surgery is most often directed at removal of diseased or injured teeth by the least invasive method possible. Some procedures available can preserve traumatized or infected teeth. Complications of dental surgery are well documented and often encountered by veterinary surgeons. Principles of debridement, curettage, lavage and ventral drainage combined with appropriate medicinal management can reduce complications and lead to successful outcome after dental surgery.

Animals↗

The effects of intra-articular methylprednisolone and exercise on the mechanical properties of articular cartilage in the horse.

INTRODUCTION: Intra-articular corticosteroids are widely used as anti-inflammatory agents for symptomatic management of arthritis, but their administration with concurrent exercise remains controversial. Biochemical and morphologic analysis of treated cartilage has revealed conflicting results, but previous biomechanical assessment has not been undertaken. OBJECTIVE: To compare the biomechanical properties of intra-articular methylprednisolone acetate (MPA) and diluent treated cartilage in treadmill exercised horses. METHODS: Eight 2-year-old female horses had MPA or diluent administered into contralateral middle carpal joints at 14 day intervals for a total of four treatments per horse. Horses underwent a standard treadmill exercise protocol until euthanasia (day 70). Standard sites were tested on the third, radial and intermediate carpal bones using an automated indentation apparatus to obtain the creep and recovery behavior of the articular cartilage. Using previously validated biphasic creep indentation methodology, aggregate modulus, Poisson's ratio, permeability, shear modulus, thickness, creep and recovery equilibrium times and percent recovery were obtained at each site. Results were analyzed using ANOVA and multiple comparisons of the means (P < 0.05). RESULTS: Cartilage intrinsic material properties and thickness demonstrated significant differences between MPA and diluent treated joints. Diluent treated cartilage had a 97% increase in compressive stiffness modulus (P = 0.0001), was 121% more permeable (P = 0.0001), had 88% increase in shear modulus (P = 0.0001), and was 24% thicker (P = 0.0001) than MPA treated articular cartilage. CONCLUSIONS: The findings indicate that repetitive intra-articular administration of MPA to exercising horses alters the mechanical integrity of articular cartilage, which could lead to early cartilage degeneration.

Analysis of Variance↗

Quantification of exercise-induced pulmonary haemorrhage with bronchoalveolar lavage.

Exercise-induced pulmonary haemorrhage (EIPH) causes serious economic losses in the horse racing industry. Endoscopic examination indicates that 40-90% of horses exhibit EIPH following sprint exercise, but the limitations of the endoscope prevent diagnosis in many horses. Bronchoalveolar lavage (BAL) was utilised to detect red blood cells (RBCs) in the terminal airways in 6 horses. Two lavages were performed at weekly intervals prior to exercise, one within 90 min after exercise, and 5 at weekly intervals after exercise. The horses were exercised strenuously at 12.5-14.6 m/s on a treadmill (3 degree incline). Heart rates ranged from 192-207 beats/min, and mean pulmonary arterial pressures (mPAP) ranged from 80-102 mmHg. Neither epistaxis nor endoscopic evidence of EIPH was seen in any of the 6 horses following exercise. However, the number of RBCs in the lavage fluid increased significantly over control values immediately after exercise in all horses but returned to control values by one week after exercise. Haemosiderophages in the BAL fluid did not increase until one week after exercise and remained elevated for 3 weeks after exercise. Twenty per cent of the total population of alveolar macrophages contained haemosiderin. A positive relationship occurred between the number of RBCs in the lavage fluid and mPAP; the amount of haemorrhage increased as the mPAP exceeded 80 to 90 mmHg. The results with BAL used as the diagnostic tool, suggest that all strenuously exercised horses may exhibit EIPH; the amount of haemorrhage appears to be associated with the magnitude of the high pulmonary arterial pressure.

Animals↗

Evaluation of mild lameness in horses trotting on a treadmill by clinicians and interns or residents and correlation of their assessments with kinematic gait analysis.

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 (kappa 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.

Animals↗

Laparoscopic surgical approach and anatomy of the abdomen in llamas.

OBJECTIVE: To describe 3 laparoscopic approaches for, and the normal laparoscopic anatomy of, the abdomen in adult llamas and to evaluate the effects of laparoscopy in those llamas. DESIGN: Prospective clinical trial. ANIMALS: Six adult castrated male llamas. PROCEDURE: After induction of general anesthesia, 3 surgical approaches to the abdomen were performed: left paralumbar, ventral midline, and right paralumbar. The abdomen was systematically examined, and anatomic features described. After recovery from anesthesia, all llamas were examined daily for 10 days and CBC was repeated 24, 72, and 120 hours after laparoscopy. RESULTS: Laparoscopy was successfully performed in all llamas by use of the ventral midline and right paralumbar approaches. The laparoscope was inadvertently placed into the left retroperitoneal space in 1 of the 6 llamas when the left paralumbar approach was used. Also, hemorrhage into the abdomen limited the view from the left side in another llama. Various approaches allowed viewing of the first and third forestomach compartments, liver, spleen, kidneys, small intestine, ileum, proximal loop of the ascending colon, spiral colon, and urinary bladder. Postoperative findings included subcutaneous emphysema and edema. Mean WBC count peaked 24 hours after surgery (mean, 23,500 cells/microliter). Generally, neutrophil count increased and lymphocyte count decreased during the 120 hours after surgery. CLINICAL IMPLICATIONS: Laparoscopy may be used for differentiation of medical and surgical lesions in the abdomen of llamas. The site for laparoscopy should be chosen on the basis of the most likely site of the suspected lesion.

Abdomen↗

Arthroscopy in food animal practice.

Arthroscopy can be an effective technique for diagnosis and treatment of various orthopedic disorders in cattle, including septic arthritis and osteochondrosis. Cost of equipment and surgery may be prohibitive for some individuals, yet the techniques of arthroscopic surgery are proven efficacious when applied to cattle. Arthroscopic techniques may also be quite useful in the evaluation and treatment of the same disorders in sheep, goats, and camillids. The technology remains the same and applicability rests with financial constraints and the physical aspects of specific species and joints. We speculate that arthroscopy would be quite useful for exploration and treatment of the larger joints and other selected joints of these species.

Animals↗

Skeletal origins of exercise intolerance in horses.

Skeletal origins of exercise intolerance and performance failure can reside in multiple tissues. Diagnosis of injury that results in an ability to continue to exercise, yet inefficiently do so, requires familiarity with evaluation of subtle lameness and often with the specific demands of the different equine sports. Imaging is usually vital to diagnosis development and understanding of lesion influences on locomotion. Therapy is lesion dependent. Return to competitive exercise and performance is dictated by an understanding of skeletal tissue response to injury, rational progressive treatment, and a controlled reintroduction of exercise demands.

Animals↗

Diagnostic approach to exercise intolerance in racehorses.

The diagnostic approach to the exercise intolerant racehorse depends on sound, fundamental steps to allow complete examination of the entire horse in a logical, time-efficient fashion. Availability of referral diagnostic modalities should not overshadow the need for collecting a clinical history or performing a complete physical examination. The diagnostic approach to exercise intolerance can be divided into a few basic steps. The first step, conducted without the horse, is a thorough discussion about the horse with the trainer and/or owner. Many clinical histories are complex and therefore following a predetermined pattern is helpful. Racing ability, general health history, historic problems with the major body systems including the musculoskeletal, respiratory, cardiovascular, and neurologic systems should be reviewed. The next step of the examination is conducted in the stall. A complete physical examination is required. The practitioner should pay close attention to the body systems that most frequently harbor causes of exercise intolerance. Before evaluating the horse for lameness, endoscopy of the upper airway should be performed. The final step is conducted outside the stall: completion of the lameness and neurologic examination or an exercise trial followed by further diagnostic tests such as a serum chemistry profile, bronchoalveolar lavage, or imaging studies. Decision for referral is best made after the physical examination is completed and capability for further diagnostics is exhausted.

Animals↗

Exercise intolerance in endurance horses.

Endurance competition requires synchronism and development of metabolic and musculoskeletal systems. An understanding of the existence of performance-limiting factors may permit the detection of exercise intolerance that could lead to performance failure, fatigue, and exhaustion. New concepts for assessment of fitness have increased the understanding of individual capacities and deficiencies and the interaction of the different systems involved in exercise.

Animals↗