Pasteurella haemolytica A1 and Bovine Respiratory Disease: Pathogenesis

The severe fibrinonecrotic pneumonia associated with pneumonic pasteurellosis usually results from colonization of the lower respiratory tract by Pasteurella haemolytica biotype A, serotype 1(A1). Despite recent research efforts, the authors lack a detailed understanding of the interactions and host response to P. haemolytica in the respiratory tract. The authors hypothesize that management and environmental stress factors or viral infection alters the upper respiratory tract (URT) epithelium allowing P. haemolytica to colonize the epithelium. Once the URT is colonized, large numbers of organisms enter the lung where they interact with alveolar macrophages. Endotoxin, released from the bacteria, crosses the alveolar wall where it activates pulmonary intravascular macrophages, endothelium, neutrophils, lymphocytes, platelets, complement, and Hageman factor leading to complex interactions of cells and mediators. It is the progression of this inflammatory response with neutrophil influx that is ultimately responsible for the pulmonary injury. Leukotoxin is a major virulence factor of P. haemolytica that allows it to survive by destroying phagocytic cells. At subcytolytic concentrations it may also enhance the inflammatory response by activating cells to produce mediators and release reactive oxygen metabolites and proteases.     

IOHEXOL AND IOPAMIDOL MYELOGRAPHY IN THE DOG: A CLINICAL TRIAL COMPARING ADVERSE EFFECTS AND MYELOGRAPHIC QUALITY

In a blind clinical trial, adverse effects after iohexol and iopamidol myelography were evaluated in 151 dogs. Eighty-one dogs were given iohexol (240 mgI/ml) and 70 dogs were given iopamidol (200 mgI/ml) by pre-determined assignment. Each dog was evaluated postmyelographically for seizures, hyperthermia, prolonged recovery from anesthesia and intensification of pre-existing neural signs. Myelographic quality was evaluated with a subjective scoring method. In comparing iohexol and iopamidol groups, there was not a statistically significant difference in the incidence of adverse effects or in myelographic quality. Iopamidol and iohexol appeared to be equally efficacious for routine canine myelography.     

Incompatibility Between the Dimorphic Flowers of Collomia grandiflora, a Cleistogamous Species

The cleistogamous species Collomia grandiflora produces dimorphic cross-incompatible flowers on a single plant. The open or chasmogamous flower has smaller, flask-shaped stigmatic papillae, larger pollen grains, longer styles, and faster pollen tube growth rates down the style than the closed or cleistogamous flower. In intermorph crosses, pollen tube growth rates are greatly decreased and fertilization does not occur.     

Endoscopic sex determination and gonadal manipulation in Gulf of Mexico sturgeon (Acipenser oxyrinchus desotoi).

Seventeen Gulf of Mexico sturgeons (Acipenser oxyrinchus desotoi) underwent endoscopic sex determination, gonadal biopsy, and various reproductive surgeries as part of a conservation development plan. The fish were anesthetized with tricaine methanesulfonate (MS-222) buffered with sodium bicarbonate and maintained on a recirculating water anesthesia circuit. A 6-mm Ternamian EndoTip Cannula, placed through the ventral midline, midway between pectoral and pelvic fins, permitted the introduction of a 5-mm telescope. Swim bladder aspiration and CO2 insufflation of the coelomic cavity provided excellent observation. Second and third cannulae were placed under direct visual control, lateral and cranial or caudal to the telescope cannula. Sex determination was successfully performed in all fish; however, five of 17 sturgeons (29%) required endoscopic gonadal biopsy to confirm sex. Bilateral ovariectomy or orchidectomy was successfully performed in three males and four females. Unilateral ovariectomy and bilateral ligation of the müllerian ducts using an extracorporeal suturing technique was accomplished in an additional three females. No apparent morbidity was associated with the anesthesia or endoscopic surgery in any fish. The ability to safely perform minimally invasive reproductive surgery in fish may have important management and conservation benefits.     

Cyclooxygenase (COX) inhibitors and the intestine

Nonsteroidal anti-inflammatory drugs (NSAIDs) have long been used for the treatment of pain and inflammation because of their inhibitory effects on cyclooxygenase (COX). For almost as long as NSAIDs have been in use, multiple adverse effects have been noted. Assessment of many of these adverse effects have been complicated because of the discovery of multiple splice variants of the cox gene, and a greater array of COX inhibitors, especially the COX-2 selective inhibitors have become available. Some of these adverse effects cannot be readily explained by the effect of these drugs on COX. This has sparked a new field of investigation into the COX-independent effects of the COX inhibitors. The major noncyclooxygenase targets of the COX inhibitors of particular relevance to inflammation and the gastrointestinal tract are phosphatidylinositol 3'-kinase Akt signaling, uncoupling of oxidative phosphorylation, PPARgamma, nuclear factor KB, mitogen activated protein kinases, and heat shock proteins.     

Use of group-randomized trials in pet population research

Communities invest considerable resources to address the animal welfare and public health concerns resulting from unwanted pet animals. Traditionally, research in this area has enumerated the pet-owning population, described pet population dynamics in individual communities, and estimated national euthanasia figures. Recent research has investigated the human–animal bond and explored the community implications of managed feral cat colonies. These reports have utilized traditional epidemiologic study designs to generate observational data to describe populations and measure associations. However, rigorous scientific evaluations of potential interventions at the group level have been lacking. Group-randomized trials have been used extensively in public health research to evaluate interventions that change a population's behavior, not just the behavior of selected individuals. We briefly describe the strengths and limitations of group-randomized trials as they are used to evaluate interventions that promote social and behavioral changes in the human public health field. We extend these examples to suggest the appropriate application of group-randomized trials for pet population dynamics research.