Biomedical subjects
Eiji Hosoi
Publications and source records attributed to Eiji Hosoi.
Phylogenetic analysis of Theileria sp. from sika deer, Cervus nippon, in Japan.
The 18S rRNA genes of Theileria species detected in sika deer, Cervus nippon centralis in Yamaguchi and Cervus nippon yesoensis in Hokkaido, were analyzed. The percent identities of the nucleotide sequences of Theileria from Cervus nippon centralis and Cervus nippon yesoensis were more than 99%. The percent identities of the Theileria sp. from sika deer and Theileria sergenti, Theileria buffeli and Theileria cervi were 97, 96 and 95%, respectively. Phylogenetic analysis of the gene sequences also revealed that Theileria sp. detected from sika deer comprise a clade that is clearly distinct from the clade comprised of Theileria from cattle.
Expression levels of H-type alpha(1,2)-fucosyltransferase gene and histo-blood group ABO gene corresponding to hematopoietic cell differentiation.
BACKGROUND: The expression of ABO antigens on the surface of RBCs is regulated by ABO gene-encoded ABO transferase activity after the formation of the H antigen. The molecular mechanisms that control the expression of the ABO blood group antigens along with erythroid differentiation are one of the most important subjects of study in transfusion science. STUDY DESIGN AND METHODS: FUT1(H), ABO, and beta 2-microglobulin mRNA were determined by semiquantitative RT-PCR from 27 hematopoietic cultured cell lines showing various differentiation stages and cell lineages and normal PBMNCs. The expression level of each cell was analyzed with computer software (Image, NIH) and was shown as the ratio of ABO mRNA or H mRNA to beta 2-microglobulin mRNA. The H antigen was also determined by immunocytochemical methods with flow cytometry in some cell lines. RESULTS: The highest expression of H mRNA was found in KOPM-28 and HEL cell lines and a lower expression was found in the mature cells. In contrast, it was observed that H antigen expression began at the level of HEL and PL-21 cells and increased with cell maturation. The highest expression of ABO mRNA was found in K-562 and KOPM-28 cell lines and it decreased along with cell maturation. CONCLUSION: Based on these results, it is concluded that the transcription of both H and ABO genes starts early in immature peripheral blood progenitor cells but gradually decreases during cellular maturation and also that the H antigen maintains a high level of expression thereafter. These results may reflect the active synthesis of H and ABO antigens in normal hematopoietic peripheral blood progenitor cells.
Multidrug resistance in hematological malignancy.
The recent treatment of hematological malignancies appears to be unsatisfactory in child and adult patients with acute myeloid leukemia and adult patients with acute lymphocytic leukemia. A major problem in the treatment of leukemia is caused by the development of drug resistance to chemotherapeutic agents, which is already present at diagnosis or after chemotherapy as a minimal residual disease, their resistance having originated from genetic or epigenetic mutations during prior growth of the leukemia clone. It was suggested that the mechanisms of drug resistance consist of drug resistance proteins, which work as a drug efflux pump. These are the permeability-related glycoprotein (P-Gp), the multidrug-resistance associated protein (MRP), the lung resistance protein (LRP), and other MDR proteins such as the transporter associated with antigen processing (TAP), anthracyclin resistance associated protein (ARA), MRP 2-7, and breast cancer resistance protein (BCRP). In addition, anti-apoptosis mechanisms, alterations of tumor suppressor genes, altered immunogenicity, drug resistance mechanisms for individual drugs, and clinical risk factors such as white blood cell count, age, and other factors have been reported to act in drug resistance singly or in combinations. Here we describe the update of research on the biology of MDR in the hematological malignancies and also discuss how to overcome MDR and adapt the updated treatment methods in the clinical medical field.
Patients with malignant hyperthermia demonstrate an altered calcium control mechanism in B lymphocytes.
BACKGROUND: Altered Ca2+ homeostasis in skeletal muscle is a key molecular event triggering malignant hyperthermia (MH) in malignant hyperthermia-susceptible (MHS) individuals. Genetic studies have shown that mutations in the type 1 ryanodine receptor (RYR1) are associated with MH susceptibility. Because human B lymphocytes express the RYR1, it is hypothesized that Ca2+ homeostasis in B lymphocytes is altered in MHS individuals. METHODS: This study investigated the Ca2+ response of B cells to caffeine and 4-chloro-m-cresol in 13 MHS and 21 MH-negative (MHN) individuals who had been diagnosed by caffeine halothane contracture test (CHCT) and 18 healthy volunteers. Changes in [Ca2+]i in B cells were measured directly in fluo-3 loaded cells using a dual-color flow cytometric technique. Further, B cell phenotype was correlated with CHCT results in a family with the Val2168Met (G6502A) mutation. RESULTS: Caffeine-induced (50 mm) increases in [Ca2+]i in B cells were significantly greater in MHS than in MHN (P = 0.0004), control (P = 0.0001) or non-MHS (MHN and control) individuals (P < 0.0001). The 4-chloro-m-cresol-induced (400 microm) increases in [Ca2+]i were also significantly different between MHS and controls (P = 0.003) or between MHS and non-MHS (MHN and control) individuals (P = 0.0078). A study of a family with the Val2168Met mutation demonstrated expression of the RYR1 mRNA mutant in B cells from the family members with MHS phenotype and a clear segregation of genotype with B-cell phenotype. CONCLUSION: The Ca2+ responses to caffeine or 4-chloro-m-cresol in B lymphocytes showed significant differences between MHS and MHN (or control) individuals. Although the molecular mechanisms of these alterations are currently undetermined, the results suggest that the enhanced Ca2+ responses are associated with mutations in the RYR1 gene in some MHS individuals.
Tick infestation of sika deer (Cervus nippon) in the western part of Yamaguchi Prefecture, Japan.
Ticks were collected from 94 sika deer (Cervus nippon) hunted in the western part of Yamaguchi Prefecture, Japan from August to November 1999, and March to July 2000. Haemaphysalis longicornis and H. yeni were the dominant species from April to August, while H. flava and H. megaspinosa were dominant in October, November and March. This is the first report of H. yeni in the mainland of Japan. Small numbers of H. kitaokai, Amblyomma testudinarium and Ixodes ovatus were also recorded.