Yoko Hirabayashi

Learn More
Although the mechanisms underlying benzene-induced toxicity and leukemogenicity are not yet fully understood, they are likely to be complicated by various pathways, including those of metabolism, growth factor regulation, oxidative stress, DNA damage, cell cycle regulation, and programmed cell death. With this as a background, we performed cDNA microarray(More)
Transgenic (Tg) mice overexpressing human thioredoxin (TRX), a small redox-active protein, were produced to investigate the role of the protein in a variety of stresses. Bone marrow cells from TRX-Tg mice were more resistant to ultraviolet C-induced cytocide compared with those from wild type (WT) C57BL/6 mice. TRX-Tg mice exhibited extended median and(More)
Oncostatin M (OSM) is a multifunctional cytokine that belongs to the interleukin 6 (IL-6) family. As OSM is expressed in adult as well as embryonic hematopoietic tissues, OSM has been considered to play a role in hematopoiesis. To uncover roles of OSM, we have generated mutant mice deficient in the OSM-specific receptor beta subunit (OSMR). While OSMR-/-(More)
Benzene can induce hematotoxicity and leukemia in humans and mice. Since a review of the literature shows that the CYP2E1 knockout mouse is not known to possess any benzene toxicity, the metabolism of benzene by CYP2E1 in the liver is regarded to be prerequisite for its cytotoxicity and genotoxicity, although the mechanism is not fully understood yet.(More)
In this study, Trp53-deficient and wild-type mice of both C57BL/6 and C3H/He strains were exposed to benzene (33, 100, and 300 ppm; 6h/day, 5 days/week for 26 weeks) and then observed for lifetime. As results, first, the incidence of nonthymic lymphomas in C57BL/6 mice and acute myeloid leukemias (AMLs) in C3H/He mice showed linear responses at the lower(More)
The study examined the feasibility of screening for hepatotoxicity by an in vitro gene expression analysis using rat primary hepatocytes and Affymetrix Rat Toxicology U34 arrays. Hepatocytes were exposed for 6 or 24 h to eight drugs, with different mechanisms of hepatotoxicity, at one third of the cytotoxic concentration TC50, i.e. acetaminophen,(More)
Benzene-induced hematopoietic toxicity is an aryl hydrocarbon receptor (AhR)-related adverse effect that is not exhibited in AhR-knockout (KO) mice. In the hematopoietic system, the steady-state expression of AhRs is limited in the hematopoietic progenitor cells; thus, a hierarchical hematopoietic impairment starts from hematopoietic progenitor cells after(More)
Membrane channel connexin (Cx) forms gap junctions that are implicated in the homeostatic regulation of multicellular systems; thus, hematopoietic cells were assumed not to express Cxs. However, hematopoietic progenitors organize a multicellular system during the primitive stage; thus, the aim of the present study was to determine whether Cx32, a member of(More)
Bone marrow (BM) functions as the primary hematopoietic tissue throughout adult life by providing a microenvironment for the proliferation, differentiation, and retention of hematopoietic stem cells and progenitors. We describe novel roles for oncostatin M (OSM) in the BM hematopoietic microenvironment. Hematopoietic progenitor activity in OSM-deficient(More)
OBJECTIVES Previously, we found a clear decrease in the incidence of radiation-induced myeloid leukemia in C3H/HeMs mouse caused by caloric restriction (CalR). In this report, CalR before and after irradiation was examined to determine whether they exert different effects on the prevention of radiation-induced myeloid leukemogenesis and the consequent(More)