title: Spontaneous nonthymic T cell lymphomas in young Wistar rats.
abstract: Spontaneous acute lymphomas and related leukemias, occurring in three of 2,974 male Wistar rats used as controls in toxicity studies during the last 14 years (1974-1987), were examined by light and electron microscopy and by using immunohistochemistry. At autopsy, conspicuous hepatosplenomegaly was noted. Morphologically, tumor cells of all three rats were medium-sized lymphocytes with many mitotic figures proliferating mainly in the spleen, liver, and bone marrow. Virus-like particles were not detected. Immunohistochemically, almost all tumor cells were positive for thy-1 antigen but negative for hematopoietic and differentiation markers such as W3/13, W3/25, OX4, OX8, and OX12. The results suggest that the lymphomas in these three rats were derived from T cells.
authors.affiliation: Hikari Branch, Drug Safety Evaluation Laboratories, Takeda Chemical Industries, Ltd., Yamaguchi, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Hayashi
authors.forename: T
authors.initials: T
authors.lastname: Nonoyama
authors.forename: H
authors.initials: H
authors.lastname: Miyajima
mesh_terms: D000818:Animals; D001853:Bone Marrow / Q000276:immunology / Q000648:ultrastructure; D002467:Cell Nucleus / Q000648:ultrastructure; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D006056:Golgi Apparatus / Q000648:ultrastructure; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000648:ultrastructure / Q000662:veterinary*; D008099:Liver / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D051381:Rats; D011919:Rats, Inbred Strains; D012376:Rodent Diseases / Q000473:pathology*; D013154:Spleen / Q000648:ultrastructure*; D013601:T-Lymphocytes