AN INTRATHORACIC MALIGNANT PERIPHERAL NERVE SHEATH TUMOR IN A DOG

A 7-year-old, neutered male Labrador Retriever presented for a persistent, productive cough and regurgitation. Radiography, ultrasonography, and computed tomography confirmed a large, smoothly marginated intrathoracic mass causing tracheal compression. The mass was removed via a thoracotomy, and a malignant peripheral nerve sheath tumor, most likely originating from the ventral spinal nerve roots, was confirmed using immunohistochemistry.     

Bronchial cartilage dysplasia with multifocal lobar bullous emphysema and lung torsions in a pup.

Bronchial cartilage dysplasia is believed to have caused lobar bullous emphysema in a 5-month-old Chow Chow that had exercise intolerance, progressive dyspnea, and episodic cough. Radiography of the thorax revealed hyperlucency of the left hemithorax, displacement of the mediastinum and heart to the right, and flattening of the diaphragm. The pup died shortly after the radiographs were obtained. Necropsy revealed massive hyperinflation with 180 degrees torsion of the cranial portion of the left cranial lung lobe, and hyperinflation with less than 180 degrees torsion of the right accessory lung lobe. Histologic examination of the affected lung lobes revealed a lack of bronchial cartilage, loss and displacement of alveolar walls, and bulla formation that resembled congenital (infantile) lobar emphysema of human beings. In this pup, lung lobe torsions may have been predisposed by bronchial cartilage dysplasia.     

Experimental Paragonimus kellicotti infection in dogs

The life cycle of Paragonimus kellicotti was studied in dogs fed 25 or 50 metacercariae obtained from the hearts of naturally infected crayfish. Young flukes excysted in the intestines and appeared in the peritoneal cavity within 7–14 days after inoculation (DAI) and in the pleural cavity from 7 to 43 DAI. Immature flukes penetrated the pulmonary parenchyma between 7 and 10 DAI and became sexually mature between 28 and 35 DAI. Virtually all growth of the flukes occurred in the lungs. Eggs first appeared in feces 30 DAI. Pulmonary lesions were caused by the penetration and growth of flukes and the lesions were first detected by thoracic radiography 3 weeks after inoculation. Clinical signs were generally mild and consisted of an intermittent cough. Two dogs died suddenly of pneumothorax due to the rupture of cysts 32 and 35 DAI, respectively.     

Clinical evaluation of American river otters in a reintroduction study

Ten American river otters (Lutra canadensis) were evaluated clinically before release into Oklahoma waterways. Otters were immobilized for physical, radiographic, and electrocardiographic examinations and for collection of blood samples. Hematologic and serum biochemical analyses, urinalyses, parasitologic examinations, surgical omental biopsies, and necropsy findings were included. Respiratory tract disease, bacterial and parasitic infections, and starvation apparently were contributing causes of postrelease mortality in 4 of the otters.     

Modeling Adaptive Mutation of Enteric Bacteria in Surface Water Using Agent-Based Methods

Mechanistic models of enteric bacteria fate and transport in surface waters are important tools for research and management. The existing modeling approach typically assumes that bacteria die in a first-order fashion, but a recent study suggests that bacteria can mutate relatively rapidly to a strain better adapted to the surface water environment. We built an agent-based model that simulates individual wild-type and mutant Escherichia coli cells. The bacteria die, grow on the natural assimilable organic carbon available to E. coli, divide and mutate. We apply the model to laboratory experiments (from the literature and new ones) and the Charles River in Boston. Laboratory applications include decay, growth, and competition (between wild-type and mutant) in various types of surface water. For decay experiments, the stochastic mutation process in the model can produce both first-order and biphasic decay patterns, which is consistent with observations in the literature. For the Charles River, the model can reproduce the main patterns observed in the field data. The model applications provide evidence in support of the mutation mechanism. However, the mutation model does not produce better predictions for the Charles River than a previous model based on labile and resistant subpopulations.     

The Effect of Calcium Sprays and Fruit Thinning on Bitter Pit Incidence and Calcium Content in ‘Honeycrisp’ Apple

‘Honeycrisp’ is a recently released cultivar of apple (Malus x domestica) developed by the University of Minnesota, now in high demand by growers and consumers. This cultivar is susceptible to bitter pit, especially when the trees are young and the fruit load is low. The effects of calcium (Ca) sprays, fruit thinning, vegetative growth, fruit and leaf nutrient concentration on bitter pit incidence, and two sampling methods for nutrient analysis were studied. Bitter pit incidence was associated with several variables, including Ca and phosphorus (P) concentrations in leaves and fruits, magnesium (Mg) concentration in leaves, and yield parameters. Fruit Ca concentration and content for the growing season were modeled, which allowed the determinations of Ca levels associated with bitter pit incidence. Our data suggest that plug analysis was less sensitive than fruit-segment analysis for finding differences in Ca concentrations.