Laboratory animal science最新文献

Background and purpose: A new strain of mouse, named FLS (fatty liver Shionogi), which develops spontaneous fatty liver without obesity, was established by inbreeding. Morphologic, physiologic, and genetic characterization of the strain was done.

Methods: Characteristics of male FLS mice were compared with those of the sister strain, dd Shionogi (DS), which does not develop spontaneous fatty liver. A genetic cross experiment was performed by mating FLS with C3H/He/Shi mice.

Results: The hepatocytes of neonatal FLS mice contained fine lipid droplets throughout the lobules, and large lipid droplets appeared as mice aged. Liver triglyceride concentrations of FLS mice were fivefold higher than those of DS mice, but serum lipid concentrations and the lipoprotein profile did not indicate abnormalities. Higher plasma aspartate transaminase and alanine transaminase activities in FLS, compared with DS mice, suggested hepatocellular lesions. The genetic cross experiment suggested that the fatty liver formation is a complex polygenic trait.

Conclusion: The FLS mice develop a progressive hepatic steatosis without obesity and diabetes. The FLS mouse might be a good model for investigating hepatic disorders accompanied by fatty liver unrelated to alcoholism or obesity.

Background and purpose: The anophthalmic white (Wh) gene in Golden Syrian hamsters (Mesocricetus auratus) is autosomal semi-dominant and causes several developmental defects, including hearing loss. The Wh mutation is thought to be homologous to Waardenburg syndrome in humans, apparently affecting similar developmental processes. The purpose of this study was to assess the hearing of hamsters in the AN/As-Wh strain.

Methods: Using auditory brainstem responses, electrophysiologic activity was determined in 20 hamsters of the AN/As-Wh strain, with the aim of elucidating hearing status. Hamsters were classified into five genotypes and were evaluated by use of click stimuli.

Results and conclusion: Hamsters assigned to the genotypes differed in their hearing sensitivity and could be classified into categories of normal hearing, moderate hearing loss, and profound hearing loss.

Background and purpose: Expression of the HER2/neu proto-oncogene, a receptor-like transmembrane protein expressed at low levels on some normal cells, is markedly increased in a subset of human breast, colon, lung, and ovarian cancers. A humanized HER2/neu antibody has been tested as a therapeutic agent in several clinical trials, with promising results. We have developed a family of anti-HER2/neu fusion proteins. To evaluate the immunologic efficacy of these proteins, it is critical that tumors expressing the target antigen can grow in immunologically intact mice.

Method: To produce murine tumors expressing human HER2/neu on the surface, CT26, MC38, and EL4 murine cell lines were transduced by use of a retroviral construct containing the cDNA encoding the human HER2/neu gene.

Results: Histologic features and kinetics of tumor growth in subcutaneous space of the human HER2/neu-expressing cells were similar to those of the respective parental cell lines. Intravenous inoculation with these cells induced disseminated malignant disease. Flow cytometric and immmunohistochemical analyses of freshly isolated tumors revealed in vivo expression of human HER2/neu. Secretion of antigen was not detected by use of an ELISA.

Conclusion: Although an antibody response against the human HER2/neu antigen was observed, this response does not affect the growth rate of the HER2/neu-expressing cells. These murine models may be useful tools for evaluation of anti-cancer therapeutic approaches that target human HER2/neu.

Background and purpose: National Institutes of Health's Division of Comparative Medicine has sponsored a multi-institutional program for the establishment of specific-pathogen-free (SPF) macaque colonies. B virus (Herpesvirus simiae, Cercopithecine herpesvirus type 1) has been targeted in this surveillance. Participating institutions have established individual timetables for frequency of testing and types of monitoring and husbandry techniques, all with the common goal of producing pathogen-free monkeys for research. The greatest biosecurity threat to the program comes from failure to detect seronegative latent infections, either in first-year macaques or macaques introduced in subsequent years, although these are supposed to operate as closed colonies.

Methods: From January 1990 through December 1996, we screened macaques for B virus, using enzyme-linked immunoabsorbant assay (ELISA) and Western blot analysis.

Results: During the first year, 1,097 macaques from six colonies were tested, and 88.4% tested negative for B virus. During the seventh year, 1,843 were tested, of which 99.7% tested negative. Seropositive macaques were detected as late as the seventh year.

Conclusions: An aggressive program to establish an SPF colony of captive breeding macaques can be effective in reducing the risk of B-virus exposure.