Repair of an Ulnar Fracture With Radial Luxation in a Horse

An ulnar fracture with radial luxation (Monteggia fracture) was repaired in a horse. Reduction of the radial luxation was difficult, requiring 2 incisions, limb traction, neuromuscular blockade, and direct radial manipulation. The ulnar fracture was repaired by use of a dynamic compression plate. Three months postoperatively, the horse was free of any apparent lameness.     

Approximating the degrees of freedom for contrasts of genotypes laid out as subplots in an alpha-design in a split-plot experiment

Alpha‐designs have become popular in cultivar trials. Analysis is based on a mixed model. As a result of imbalance, inference tests require approximate methods. This paper investigates the Type I error control of different Satterthwaite approximations for the denominator degrees of freedom of Wald‐type F‐tests and t‐tests in a two‐factorial alpha‐design with cultivars as the subplot factor and management intensities (fertilization, plant protection) as the main plot factor. Simulation results demonstrate good error control for cultivar comparison at the same intensity, with the need for an approximation which diminishes as the number of cultivars increases. By contrast, a comparison of intensities entails a more substantial departure from the nominal significance level, and this is not entirely offset by any of the approximations. The methods are demonstrated using two real data sets.     

Acquisition-Based Assessment and Property Tax Inequalities after California's 1978 Proposition Thirteen

This paper examines the shift from current market value assessment to acquisition-based assessment as mandated by a little-noticed provision of California's 1978 Proposition Thirteen. The distributional effects of the reformed property tax system are studied for a 300-house, ten-neighborhood sample in Davis, California. Micro-area tax inequalities for similar properties greatly increased from 1978 to 1985. By 1988, however, intra-area and inter-area inequalities in tax payments were diminishing slightly due to a low inflation rate and increased property turnover (resales). Because of its social policy consequences, acquisition-based assessment is an element of California's tax revolt that other jurisdictions should not emulate.     

A Developmental Model for Free Vascularized Bone Transfers in the Dog

An autogenous free vascular bone transfer using a segment of ulna along with its periosteum and vascular pedicle was developed. The vascular pedicle, based on the common interosseous artery and vein, emerged where muscular branches from the cranial interosseous artery enter the extensor carpi ulnaris and lateral digital extensor muscles. Four autogenous heterotopic (ulna to tibia) vascular transfers by microvascular anastomosis and two avascular transfers were performed to compare the osteogenic potential and viability of free revascularized grafts with avascular bone grafts. Successful microvascular anastomosis was demonstrated in three of the four vascular transfers by early bone scanning using technetium-labeled polyphosphate. Radiographically, there was more periosteal new bone and callus formation in the successfully revascularized bone transfers than in the failed vascular transfer and the avascular controls. Histologically, viable bone with an intact medullary and periosteal vascular supply was recognized in the grafts successfully revascularized by microvascular anastomosis.     

Effect of Four Antimicrobial Lavage Solutions on the Tarsocrural Joint of Horses

Three concentrations of povidone-iodine (0.1% w/v, 0.2% w/v, 0.5% w/v) and one concentration of chlorhexidine (0.5% w/v) were selected as antimicrobial joint lavage solutions. Through-and-through joint lavage was performed with one of these antimicrobial solutions on a tarsocrural joint of 12 horses. The contralateral tarsocrural joints (control limbs) were lavaged with a balanced electrolyte solution (BES). The effect of the lavage solution on the joints was evaluated with respect to lameness, foot flight pattern, soreness to joint palpation, articular and periarticular enlargement, and synovial fluid composition on Day 1,4, and 8 postlavage. On Day 8 postlavage, all horses were euthanized and the tarsocrural joints were examined.
All solutions induced a synovitis. Based on clinical assessment, synovial fluid protein levels, color, clarity, mucin clot forming ability, gross appearance of the joint at necropsy, and synovial membrane histologic evaluation, a similar, mild, transient, synovitis was induced by the BES and 0.1% povidone-iodine (PI) solution. The 0.2% PI solution induced a more prolonged neutrophilic response and poorer mucin clot forming ability in the synovial fluid as compared to the BES.
The 0.5% PI and 0.5% chlorhexidine solutions produced severe lameness, soreness to joint palpation, and limb enlargement. The elevated synovial fluid total protein content persisted significantly longer (p < 0.05) than the corresponding control (BES) solution. Histologic evaluation of the synovial membrane confirmed the presence of a moderate to severe neutrophilic synovitis in these treatment groups.     

High-Frequency Ventilation A Review

High-frequency ventilation (HFV) is a form of artificial ventilation that uses higher rates and smaller tidal volumes than those used with conventional mechanical ventilation (intermittent positive pressure ventilation [1PPV]). HFV is divided into three categories based on the rate and type of equipment used: 1) high-frequency positive pressure ventilation administered through a system with low internal compliance having an expiratory valve to maintain positive airway pressure during expiration and rates of 60 to 120/minute; 2) high-frequency jet ventilation delivered through an open system or a system with an expiratory valve at rates of 120 to 400/minute; and 3) high-frequency oscillation using open systems and rates of 400 to 2400/minute. All forms of HFV provide adequate ventilation in normal animals at lower peak and mean airway pressures, resulting in less cardiovascular depression than that associated with 1PPV. HFV provides adequate ventilation with less cardiovascular depression and risk of barotrauma than 1PPV in the presence of pulmonary disease. The exact mechanism of gas exchange during HFV is not clearly understood, but enhanced diffusion as a result of turbulent gas flow appears to be a major factor.     

Full-thickness Thoracic and Abdominal Wall Reconstruction in Dogs Using Carbon/Polycaprolactone Composite

Square 9 × 9 cm full-thickness defects were created in the thoracic wall of five dogs and the abdominal wall of five dogs. The skin was retained. Ten centimeter squares of carbon fabric with a thin polycaprolactone (PCL) lining were sutured into the defects with the PCL lining facing the viscera. The dogs were observed for 5 months. The surgical technique was simple and fast. All implants were well tolerated. Cosmetic results were excellent in nine dogs. One dog (abdominal implant) developed an infection and draining tract, and a second dog (thoracic implant) had a subclinical infection. Thoracic implants caused brief serosanguinous pleural transudate. Mild paradoxical respiratory motion disappeared by 8 weeks. Lungs were radiographically normal. At necropsy, fibrous tissue was present but lacked orientation. Loose adhesions covered 20 to 80% of implant linings. There was no significant difference in ultimate tensile strength of implant/fibrous tissue compared to control abdominal wall. No carbon fragments were observed in lymph nodes. Increased numbers of secondary follicles, plasma cells, eosinophils, and sinus histiocytes in lymph nodes suggested immunologic stimulation of undetermined significance.