William G. Schroeder

Low-cost aerosol exposure system for Guinea pigs.

BACKGROUND This project designed and tested an economical apparatus to safely expose guinea pigs to biohazardous aerosol. The goals were to design a system that can be easily decontaminated, fits in a biosafety cabinet, and affordable. METHODS It is composed of three main chambers housed in an outer box that fits within a conventionally sized biosafety cabinet. The animal chamber contains a removable housing unit for either four or eight guinea pigs. The aerosol chamber is separate to minimize contamination. The nebulizer chamber is also sealed to reduce risks from leakages. This apparatus is easily decontaminated by immersion in disinfectant. RESULTS AND CONCLUSIONS This system has been tested for safety, ergonomics, efficiency of rodent exposure to bacteria, airflow, access points, seal mechanisms, and size. This system is effective, consistent, safe and cost efficient.

Flexible low-cost system for small animal aerosol inhalation exposure to drugs, proteins, inflammatory agents, and infectious agents

The design for a simple, low-cost aerosol generation system for rodent inhalation studies is described here. This system is appropriate for low biohazard-level agents. In this study, two biosafety level 2 agents, Pasturella pneumotropica and Pseudomonas aeruginosa, were tested successfully. This system was also used to immunize mice and guinea pigs in ovalbumin-based models of pulmonary inflammation. This design is appropriate for studies with limited budgets and lower-level biosafety containment.

Differential effect of Platelet Endothelial Cell Adhesion Molecule-1 (PECAM-1) on leukocyte infiltration during contact hypersensitivity responses

Background 2′–4′ Dinitrofluorobenzene (DNFB) induced contact hypersensitivity is an established model of contact sensitivity and leukocyte migration. Platelet Endothelial Cell Adhesion Molecule-1 (PECAM-1) deficient mice were used to examine the role of PECAM-1 in the migration capacity of several different leukocyte populations after primary and secondary application. Results γδ T lymphocytes, granulocytes, and Natural Killer cells were most affected by PECAM-1 deficiency at the primary site of application. γδ T lymphocytes, granulocytes, DX5+ Natural Killer cells, and, interestingly, effector CD4+ T lymphocytes were most affected by the loss of PECAM-1 at the secondary site of application. Conclusions PECAM-1 is used by many leukocyte populations for migration, but there are clearly differential effects on the usage by each subset. Further, the overall kinetics of each population varied between primary and secondary application, with large relative increases in γδ T lymphocytes during the secondary response.

Mutant forms of bcr-abl deficient in inducing abi degradation show different leukemogenic activity

Abstract Bcr-Abl elicits the ubiquitin-dependent degradation of Abl interactor (Abi) proteins, a family of proteins that antagonize the oncogenic potential of Abl. Significantly, expression of the Abi proteins is lost in cell lines and bone marrow cells isolated from patients with aggressive Bcr-Abl-positive leukemias. To determine the role of Abi degradation in Bcr-Abl-induced leukemogenesis, we have mapped the sequences in Bcr-Abl that are required for inducing Abi degradation. The deletion of C-terminal proline-rich sequences (p185 Bcr-AblΔ924-1018 ) severely impairs Bcr-Abl-induced Abi degradation. The double deletions of the SH3 domain and C-terminal proline-rich sequences (p185 Bcr-AblΔ924-1018 ) completely abolish the degradation of Abi proteins. We then compared the leukemogenic activity of these mutant forms of Bcr-Abl to that of the wild type Bcr-Abl in a murine bone marrow transduction/transplantation model. Like wild type P185 Bcr-Abl , both p185 Bcr-AblΔ924-1018 and p185 Bcr-AblΔSH3Δ924-1018 transform mouse bone marrow cells with similar potency, as judged by factor-independent growth in an agar colony assay. The mutant forms of Bcr-Abl, however, showed different leukemogenic activity in mice. Mice reconstituted with wild type P185 Bcr-Abl transduced marrow cells developed chronic myeloid leukemia (CML)-like disease and died in 5–7 weeks after transplantation. The peripheral white blood cell (WBC) count of these mice was significantly elevated and the mice had enlarged spleens. Mice reconstituted with p185 Bcr-AblΔ918-1018 transduced marrow cells also died in 5–7 weeks. The majority of these mice, however, did not show the elevated WBC count or the spenomegaly, suggesting that they died of a disease other than CML. Furthermore, mice reconstituted with p185 Bcr-AblΔSH3Δ924-1018 transduced marrow cells survived much longer post-transplantation without the elevated WBC count. These results are consistent with the hypothesis that Abi degradation is involved in the development of Bcr-Abl positive CML. Studies are now in progress to define the pathology of diseases caused by mutant forms of Bcr-Abl.