Evaluation of a method for experimental induction of osteoarthritis of the hip joints in dogs

OBJECTIVE: To evaluate a method for experimental induction of osteoarthritis in the hip joints of dogs. ANIMALS: 12 mixed-breed dogs. PROCEDURE: A unilateral triple pelvic osteotomy was performed. In 6 dogs, the iliac osteotomy was repaired with 45 degrees of internal rotation, reducing coverage of the femoral head by the acetabulum. In the other 6 dogs, the fragments were repaired in anatomic alignment. Radiography, force plate evaluations, and subjective lameness evaluations were performed before and after surgery. Dogs were euthanatized 7 months after surgery, and samples of cartilage and joint capsule were examined histologically. RESULTS: Subjective lameness scores, radiographic appearance of the hip joints, and Norberg angles were not significantly different between groups; however, force plate evaluations did reveal significant differences in vertical ground reaction forces. Femoral head coverage was significantly decreased with rotation of the acetabulum. Mild inflammatory changes were discernible in the joint capsule and articular cartilage of some dogs in both groups. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that 45 degrees internal rotation of the acetabulum does not consistently induce biologically important osteoarthritic changes in the hip joints of dogs.     

Recovery from acidification in Lake Örvattnet,Sweden

Lake Örvattnet has been monitored extensively for both chemical and biological variables since 1967. The lake acidified during the 1960's and pH was mostly below 5 throughout the 1970's. Due to the acidification, peat moss (Sphagnum spp.) expanded over the lake bottom and the only surviving fish species was perch (Perca fluviatilis), but it experienced reproduction problems. In the mid 1980's, the Sphagnum cover collapsed, and by 1989 it had almost disappeared. There has been a clear recovery of the perch population. Recovery of the lake is also recorded by diatom assemblages in the lake sediment. Diatom-inferred pH increased from 4.7 to 4.9. The development of measured lake-water pH is unclear, but acid episodes in spring have become less severe. By 1993, atmospheric sulphate deposition had decreased by 30–40% in this area of Sweden compared to the late 1960's. Lake-water sulphate concentrations have decreased by ～30% since the 1960's. Nitrogen deposition has increased over the last decades, but is not yet contributing to lake acidification. No major land-use changes have occurred and changes in hydrology cannot explain the observed changes in chemistry and biology. We ascribe the recent recovery in the lake to reduced deposition of sulphate. In conclusion, Lake Örvattnet has begun to recover from acidification.     

Survey of factors influencing faculty decisions on international veterinary work

Faculty members at US colleges of veterinary medicine can encounter opportunities to work as a veterinarian in a foreign country. Institutions, governments, and other organizations can more effectively recruit faculty for these positions if they understand the characteristics of the individuals who are most likely to participate in these programs. The purpose of this study was to determine what characteristics influence veterinary faculty's desire to participate in foreign programs. Results illustrated that position type (tenure, clinical), rank (assistant professor, associate professor, full professor), gender, and the presence of pre-elementary aged children were significantly associated with willingness to work in a foreign country. In addition, survey respondents who indicated that the duration of the assignment was of high importance were less willing to travel than respondents who indicated that the duration of the assignment was of moderate importance or lower. The results from this survey provide important information about the characteristics of individuals more willing to participate in foreign programs. This information allows targeted recruiting by organizations, facilitating veterinary work in foreign countries.     

EVALUATION OF CANINE LUMBOSACRAL STENOSIS USING INTRAVENOUS CONTRAST-ENHANCED COMPUTED TOMOGRAPHY

The objective of this study was to evaluate intravenous contrast-enhanced computed tomography as a technique for predicting the within-level location(s) of compressive soft tissues in the canine lumbosacral spine. Pre-operative intravenous contrast-enhanced computed tomography of the L5-S3 vertebral levels was performed in 12 consecutive large breed dogs with lumbosacral stenosis. The images were evaluated for enhancement of soft tissues by two radiologists who were unaware of the surgical findings. For each within-level location (dorsal canal, ventral canal, right lateral recess, left lateral recess) enhancement was classified as present, absent or equivocal. The results were compared with the results of surgical exploration and histopathology of excised tissues. The positive predictive values of intravenous contrast-enhanced computed tomography for compressive soft tissues involving the dorsal canal, ventral canal and lateral recesses were 83%, 100%, and 81% respectively. Negative predictive values for compressive soft tissues involving these locations were 29%, 50%, and 40% respectively.     

Characteristic Fly-ash Particles from Oil-shale Combustion Found in Lake Sediments

Fly-ash particles accumulate in sediments and can be used to assess spatial distribution and temporal trends of atmospheric deposition of pollutants derived from high temperature combustion of fossil fuels. Previous work has concerned fly-ash derived from oil and coal. Oil-shale is the main fossil fuel used in Estonia and a major source of atmospheric pollution in the Baltic states. To assess if oil-shale power plants produce specific fly-ash particles, we used scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) to compare fly-ash particles from oil-shale combustion with particles from oil and coal combustion. Two types were analysed, large black (10–30 μm) and small glassy (<5 μm) spheroidal particles. Although particle morphology to some extent is indicative of the fuel burnt, morphological characters are not sufficient to differentiate between particles of different origin. However, our results indicate that with EDX analysis the fly-ash from oil-shale can be distinguished from oil and coal derived particles in environmental samples. Concentrations of large black and small glassy spheroidal fly-ash particles in a sediment core from an Estonian lake showed similar trends to oil-shale combustion statistics from Estonian power plants.     

Comparison of stance time and velocity as control variables in force plate analysis of dogs.

OBJECTIVE: To investigate effects of the use of stance time or velocity as control variables on ground reaction forces in lame dogs. ANIMALS: 12 dogs with pelvic osteotomies. PROCEDURE: Data for ground reaction forces were obtained preoperatively and at 2, 4, 6, 8, 12, 16, 20, 24, and 28 weeks postoperatively, using velocity and stance time as control variables. Ground reaction forces obtained were compared between the 2 methods of data collection, as were velocities and stance times of the trials. RESULTS: Significant differences in ground reaction forces were not found between the use of velocity or stance time as a control variable at any time. Also, significant differences in stance times or velocities were not found between the 2 methods of data collection. Greatest variation in stance time and velocity was found during periods of greatest lameness. CONCLUSIONS AND CLINICAL RELEVANCE: Use of stance time as a control variable in force plate analysis does not lead to significantly different results from use of velocity as a control variable, indicating that either method may be used in force plate analysis of dogs.     

In vitro evaluation of biomechanical effects of multiple hemilaminectomies on the canine lumbar vertebral column

OBJECTIVE: To conduct an in vitro investigation of the biomechanical characteristics of the canine lumbar spinal column in flexion and extension and measure the destabilizing effects of multiple consecutive unilateral and bilateral hemilaminectomies. SAMPLE POPULATION: 30 isolated multisegmental spinal units (L1-L4) from nonhypochondroplastic dogs weighing 15 to 30 kg. PROCEDURES: Physically normal and surgically altered spinal specimens were subjected to 4-point bending in flexion and extension to determine effects of multiple consecutive hemilaminectomies on the basis of analysis of test system load-displacement data. Six groups with 5 spinal columns in each were defined on the basis of the following procedures: hemilaminectomy at L2-L3, 2 adjacent hemilaminectomies at L1-L3, 3 adjacent hemilaminectomies at L1-L4, bilateral hemilaminectomies at L2-L3, 2 bilateral hemilaminectomies at L1-L3, and no hemilaminectomy (intact). Spinal stability before and after surgery was determined in all groups. Each group served as its own control for nondestructive testing. Spinal strength was evaluated through destructive testing to determine deformation at failure, strength to failure, and mode of catastrophic failure. The intact group served as the control for destructive testing. RESULTS: Stability in extreme flexion and extreme extension did not change significantly following any hemilaminectomy procedure. Postoperative stability within the neutral zone was significantly decreased in all groups. Range of motion within the neutral zone was not significantly different from the intact condition in any group. CONCLUSIONS AND CLINICAL RELEVANCE: Multiple hemilaminectomies did not decrease stiffness of the lumbar spinal column during flexion and extension. These results support clinical recommendations regarding multiple consecutive hemilaminectomies in dogs.     

Clinical management of flail chest in dogs and cats: a retrospective study of 24 cases (1989-1999)

Cases of flail chest injury for 24 client-owned companion animals following various traumas were evaluated. Concurrently sustained injuries, initial emergency treatments, and definitive treatment and outcome for regimens that utilize stabilization of the flail segment were compared with cases treated with no stabilization. Flail chest was confirmed in 24 animals: 21 dogs and three cats. There was an even division (12 each) of right and left flail segments. The median number of ribs involved was three (range, two to seven). Flail segment stabilization was performed in nine, and 15 were treated with no stabilization. Statistical analysis using multiple data permutations evaluating all combinations failed to reveal a significant difference in outcome between stabilized and unstabilized cases.