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Biomedical subjects

A Shibuya

Publications and source records attributed to A Shibuya.

At least 37 records · Page 2Linked to original sources
PubMed2000

Dominant expansion of human T cells in non-obese diabetic/severe combined immunodeficiency mice implanted with human bone fragments.

OBJECTIVE: To establish an in vivo animal model in which human T cells develop and function normally, a step toward developing new vaccines or chemical compounds that modulate immune functions and toward understanding T-cell immunity in humans. MATERIALS AND METHODS: Human bone fragments were implanted into non-obese diabetes/severe combined immunodeficiency (NOD/SCID) mice. The presence of human blood cells in the peripheral blood of these mice was monitored periodically by immunostaining and fluorescence-activated cell sorting. RESULTS: After implantation of bone fragments, dominant expansion of human T lymphocytes, rather than myeloid and B cells, was observed over a 3-month period. In some cases, the proportion of human T cells rose to 40% of the peripheral blood mononuclear cells. These T cells showed CD4/CD8 ratios similar to those observed in human peripheral blood lymphocytes and had a broad repertoire of rearranged T-cell receptor genes. Graft-versus-host reaction was not noted in any organ analyzed. To assess the suitability of NOD/SCID mice implanted with human bone fragments (hu-bone-NOD/SCID mice) as an in vivo model for HIV infection, the mice were infected with a T-lymphotropic strain of HIV-1 (NL4-3) at 7 weeks posttransplant. Serum p24 gag was detected at 2 weeks after inoculation, after which total CD4-positive cell numbers declined, as seen clinically in patients infected with HIV. CONCLUSION: Although the precise mechanism is yet to be determined by which predominant expansion of human T cells occurs in hu-bone-NOD/SCID mice, such mice appear likely to serve as a useful and versatile model for studies involving human T-cell immunity.

Animals↗
PubMed2000

A prospective study of interferon therapy modified by pre-treatment viral load in cirrhotic patients. Tokyo-Chiba Hepatitis Research Group.

BACKGROUND/AIMS: The relative role of hepatitis C virus (HCV) load and subtype as predictors of the efficacy of interferon therapy has been clarified in patients with chronic hepatitis C, but the effectiveness of interferon therapy in cirrhotic patients is still unclear. METHODS: To resolve this issue, we undertook a multicenter, randomized, and prospective study of 114 cirrhotic patients with hepatitis C virus infection. The patients were selected to undergo two different periods (6 or 12 months) of IFN therapy according to viral load. Patients with "low" viral load (< or = 10(5.8) copies/ml serum) were randomly divided into three groups, receiving 6 or 9 million units (MU) interferon three times a week for 6 months (total dose: 468 or 702 MU), or of a modified regimen using 6MU of IFN over 6 months (total dose 564 MU), while patients with "high" viral load (< or = 10(6.3) copies/ml serum) were also randomly divided into two groups of 6 or 9 MU of IFN three times a week for 12 months (total dose: 936 or 1,404 MU). RESULTS: HCV-RNA negativity rate at the completion of treatment with 6 or 9 MU IFN was 65% in patients with "low" viral load, in contrast to 14% in patients with "high" viral load. Sustained virological response was found in 40% of patients with "low" viral load irrespective of the three different regimens, in contrast to only 1 out of 35 patients (3%) with "high" viral load. Viral eradication was found in approximately 50% of patients having a low virus load (< or = 10(4.3) copies/ml) and with HCV subtype 2a. Univariate and multivariate analysis revealed that pretreatment viral load was a significant factor contributing to efficacy of IFN therapy. CONCLUSIONS: Sustained response was scarcely achieved in cirrhotic patients with high viral loads even after a 12-month course of intensive IFN therapy. This result indicates that there is a certain cut-off level of HCV RNA load which can not be eradicated.

Adult↗
PubMed2000

Fc alpha/mu receptor mediates endocytosis of IgM-coated microbes.

IgM is the first antibody to be produced in a humoral immune response and plays an important role in the primary stages of immunity. Here we describe a mouse Fc receptor, designated Fc alpha/microR, and its human homolog, that bind both IgM and IgA with intermediate or high affinity. Fc alpha/microR is constitutively expressed on the majority of B lymphocytes and macrophages. Cross-linking Fc alpha/microR expressed on a pro-B cell line Ba/F3 transfectant with soluble IgM or IgM-coated microparticles induced internalization of the receptor. Fc alpha/microR also mediated primary B lymphocyte endocytosis of IgM-coated Staphylococcus aureus. Thus, Fc alpha/microR is involved in the primary stages of the immune response to microbes.

Amino Acid Sequence↗
PubMed2000

Anti-aging effects of the traditional Chinese medicine bu-zhong-yi-qi-tang in mice.

Among the "alternative medicines," which may ably supplement modern Western medicine in the treatment of certain diseases, the holistic approach and mild nature of the majority of Traditional Chinese Medicine (TCM) may make it particularly suitable for the treatment of diseases associated with old age, as the general health of elderly patients is already compromised. The TCM formulation of bu-zhong-yi-qi-tang (B.Z.Y.Q.T.), prescribed mainly for the improvement of circulation and in particular that to the gastroenteric regions, may have anti-aging effects. In the present study, possible anti-aging effects of B.Z.Y.Q.T. were studied using normal (ICR) mice and the Dull, P/8 and R/1 strains of the Senescence Accelerated Mouse (S.A.M.). Following repeated oral administrations of B.Z.Y.Q.T. at 250 and 500 mg/kg the test mice were assessed for (1) endurance (2) learning and memory (3) neuromuscular coordination and (4) changes in the levels of monoamines in the brain. The results indicated that B.Z.Y.Q.T. improved endurance in all strains in a dose-dependent manner. At the higher dose of 500 mg/kg, it improved memory in the R/1 and P/8 S.A.M. mice. In prolonged rota-rod tests, which assessed both motor coordination and endurance, B.Z.Y.Q.T. significantly improved performance in the P/8 S.A.M. mice. Elevated dopamine and noradrenaline were observed in cortical tissues of the S.A.M./Dull and ICR mice respectively with the high dose of 500 mg/Kg, B.Z.Y.Q.T. Taken together, the results indicated that B.Z.Y.Q.T. appeared to exert anti-aging effects in mice and elevation in certain monoamines in brain cortical tissues. How and whether the monoamines changes after B.Z.Y.Q.T. treatment might be related to the behavioral effects await further investigation.

Aging↗
PubMed2000

Close association between high serum ALT and more rapid recurrence of hepatocellular carcinoma in hepatectomized patients with HCV-associated liver cirrhosis and hepatocellular carcinoma.

We investigated whether or not a high serum alanine aminotransferase (ALT) level is associated with a more rapid recurrence of hepatocellular carcinoma (HCC) in hepatectomized patients with hepatitis C virus (HCV)-associated liver cirrhosis (LC) (HCV-LC) and HCC. Thirty-three hepatectomized patients with HCV-LC and HCC of a single nodule who had no histologic evidence of portal or hepatic vein invasion and who had been followed up for more than 3 years were included in the study. They were subdivided into two groups according to their serum ALT levels, ALT being a well-known marker of inflammatory necrosis in the liver. Seventeen patients whose serum ALT levels showed several peaks or plateaus above 80 international units (IU) were designated as the high ALT group, and 16 patients whose serum ALT levels showed a sustained low level below 80 IU until the first recurrence were designated as the low ALT group, and the interval between hepatectomy and the first recurrence was observed. In the high ALT group, HCC recurred within 3 years in 70.6% of the patients. In contrast, it recurred in only 18.8% of the low ALT group within the same period (p < 0.05). There was a significant difference (p = 0.0201) between the two groups in the cumulative nonrecurrence rate. The mean interval in recurrent patients between hepatectomy and the first recurrence in the high ALT group (23.6 +/- 2.8 months; mean +/- SE) was significantly (p < 0.02) shorter than that in the low ALT group (49.3 +/- 9.7 months). The expected interval between hepatectomy and recurrence was as short as 2.8 +/- 0.5 years (mean +/- SE) in the high ALT group, compared with 5.8 +/- 0.7 years in the low ALT group (p < 0.05). These results showed that the recurrence of HCC was accelerated in the high ALT group, suggesting that suppression of the rise in ALT level after hepatectomy by treatment with anti-inflammatory drugs may prolong the interval until recurrence by about 2 years in hepatectomized patients with HCC and HCV-LC.

Aged↗
PubMed1999

Comparison of hematopoietic activities of human bone marrow and umbilical cord blood CD34 positive and negative cells.

Although the hematopoietic activities of human CD34+ bone marrow (BM) and cord blood (CB) cells have been well characterized, the phenotype of nonobese-diabetic severe combined immunodeficient (NOD/SCID) mice repopulating cells (SRCs) in CB and BM has not yet been fully examined. To address this issue, various hematopoietic activities were compared in terms of total and CD34+ CB and BM cells. Clonal culture of fluorescence-activated cell sorter (FACS) CD34+ CB and BM cells revealed a higher incidence of colony-forming cells with greater proliferation capacity in CB over BM CD34+ cells. CB CD34+ cells also demonstrated higher secondary plating efficiency over BM cells. In addition, we demonstrated that mice transplanted with CB mononuclear cells (MNCs) showed significantly higher levels of chimerism than those transplanted with BM MNCs. However, recipients of FACS-sorted CD34+ CB cells showed significantly lower levels of chimerism than those that received total CB MNCs, suggesting a role of facilitating cells in the CD34- cell population. To further analyze the role of CD34- cells, the NOD/SCID repopulating ability of FACS-sorted CB CD34-c-kit+Lin- and CD34-c-kit-Lin- cells were examined. However, SRCs were not detected in those cells. Taken together, these data suggest that CB is a better source of hematopoietic stem cells and that there are cells in the CD34- fraction that facilitate repopulation of hematopoiesis in the NOD/SCID environment.

Animals↗
PubMed1999

Physical and functional association of LFA-1 with DNAM-1 adhesion molecule.

Whereas ligation of the DNAM-1 adhesion molecule triggers cytotoxicity mediated by normal NK and T cells, this function was defective in NK cell clones from leukocyte adhesion deficiency syndrome. However, genetic reconstitution of cell surface expression of LFA-1 restored the ability of DNAM-1 to initiate anti-DNAM-1 mAb-induced cytotoxicity, indicating a functional relationship between DNAM-1 and LFA-1. Further studies demonstrated that LFA-1 physically associates with DNAM-1 in NK cells and anti-CD3 mAb stimulated T cells, for which serine phosphorylation of DNAM-1 plays a critical role. In addition, cross-linking of LFA-1 induces tyrosine phosphorylation of DNAM-1, for which the Fyn protein tyrosine kinase is responsible. These results indicate that DNAM-1 is involved in the LFA-1-mediated intracellular signals.

Animals↗
PubMed1999

WASP is involved in proliferation and differentiation of human haemopoietic progenitors in vitro.

The Wiskott-Aldrich syndrome (WAS) is an X-linked recessive disorder characterized by thrombocytopenia, immunodeficiency and eczema. X-linked thrombocytopenia (XLT) is a mild form of WAS with isolated thrombocytopenia. Both phenotypes are caused by mutation of the Wiskott-Aldrich syndrome protein (WASP) gene. In this study we investigated the role of WASP in the differentiation of CD34-positive (CD34+) cells isolated from the bone marrow of patients with WAS (n = 5) or with XLT (n = 4). Megakaryocyte colony formation was significantly decreased in patients with WAS when compared with normal controls. The formation of granulocyte-macrophage colonies and erythroid bursts were also decreased in WAS patinets. In contrast, in XLT patients, formation of all these colonies was normal. However, in vitro proplatelet formation of megakaryocytes induced by thrombopoietin was markedly decreased in both XLT and WAS. Electron microscopic examination revealed that megakaryocytes obtained from WAS or XLT patients grown in vitro had abnormal morphologic features, which seemed to be caused by defective actin cytoskeletal organization, including labyrinth-like structures of the demarcation membrane system and deviated distribution of the alpha-granules and demarcation membrane system. These observations indicate that WASP is involved in the proliferation and differentiation of CD34+ haemopoietic progenitor cells probably by its participation in signal transduction and in the regulation of the cytoskeleton.

Blood Platelets↗
PubMed1999

Treatment of infant acute lymphoblastic leukemia in Japan. Childhood Leukemia Study Group of the Ministry of Health and Welfare (Kouseisho).

Although current chemotherapeutic regimens cure as many as 70% of children with acute lymphoblastic leukemia (ALL), infants continue to show a poor outcome. In this paper, we describe the outcome in 37 ALL infants treated between 1989 and 1995 in Japan. Patients had characteristic findings of infant ALL, including hyperleukocytosis > 100 x 10(9)/l (15/37, 41%), blast cells with a CD10-negative phenotype (30/37, 81%), and 11q23/MLL involvement (21/37, 57%). Seven were treated according to Aggressive Treatment Research Group protocol, 15 according to the Ministry of Health and Welfare protocol, and 15 according to protocols of other institutions. The 3-year overall event-free survival (EFS) was 33%. The EFS was 13% for infants aged < 26 weeks at diagnosis and 43% for infants aged > 26 weeks. Infants who had blast cells with CD10 negative phenotype with 11q23/MLL involvement were also associated with poor prognosis. However, infants with CD10 positive blasts without 11q23/MLL involvement had a better outcome (EFS 75%). These results suggest that intensive chemotherapy is effective for patients with good prognostic factors, but for infants with poor prognostic factors a more aggressive approach such as stem cell transplantation might be necessary.

Female↗
PubMed1999

[5'-Nucleotidase].

Explore the source record for details and available documents.

5'-Nucleotidase↗
PubMed1999

Hemolytic crisis after excessive ingestion of fava beans in a male infant with G6PD Canton.

After ingesting fava beans, a 26-month-old Chinese-Japanese male infant showed a sickly complexion and yellowish-brownish skin and was hospitalized. Severe hemolytic anemia was observed on admission, and transfusion of 200 ml of packed red cells was required. Red cell enzyme assay revealed that the patient and the mother were deficient in glucose-6-phosphate dehydrogenase (G6PD). Subsequent molecular analysis showed that the patient had a missense mutation 1376 G to T (G6PD Canton) and his mother was a homozygote for the mutation. The patient was a son of a Chinese (Taiwanese) mother and a Japanese father. Although G6PD deficiency is rare in the original Japanese population, the number of "imported" cases could be rising rapidly. This is the first reported Japanese case of G6PD deficiency with G6PD Canton.

Amino Acid Sequence↗
PubMed1998

Hexagonal bilayer structuring activity of linker chains of an annelid giant hemoglobin from the polychaete Perinereis aibuhitensis.

Preferential activity of linker chains to clamp submultiples to form hexagonal bilayer (HBL) assembly of the multisubunit hemoglobin (Hb) of the polychaete Perinereis aibuhitensis (approximately 3.4 MDa) was demonstrated. To understand the HBL assembly that should rely on structuring activity of each subunit, reassociation in response to combining isolated subunits was monitored using gel filtration, SDS-PAGE, and transmission electron microscopy. The isolation of each subunit L, T, and M (L, linker chains; T, disulfide-bonded trimer A-b-B; M, monomeric chain a) of Perinereis Hb was made simply by exposing Hb to pH 10.5, where Hb was completely dissociated into its subunits L, T, and M. As a result, it was concluded that (i) subunits T and M have strong affinity to form an intermediate complex, submultiple D, which is a dodecamer of globin chains, 3[a. A-b-B], (ii) addition of subunit L to submultiple D brings about the formation of whole molecule, similarly (iii) addition of subunit M to T+L forms the whole molecule, and (iv) addition of subunit T to M+L brings about the formation of the whole molecule, too. The results obtained lead us to conclude that linkers do function to clamp 12 submultiples D up to a whole molecule at the final step of formation of Perinereis Hb. In summary, linkers appeared to have high affinity for submultiple D, a little affinity for subunit T, but no affinity for subunit M at all. Thus linker chains were demonstrated to preferentially clamp submultiples D together to form the HBL disc of the whole molecule.

Animals↗
PubMed1998

Characterization of a novel human natural killer-cell line (NK-YS) established from natural killer cell lymphoma/leukemia associated with Epstein-Barr virus infection.

A novel cell line was established from a patient with a leukemic-state nasal angiocentric natural killer (NK) cell lymphoma with systemic skin infiltration. The morphology of the leukemic cells was large-granular-lymphocyte (LGL), and their immunophenotype was CD2+, CD3-, CD5+, CD7+, CD16-, CD56+, and CD57-. The presence of Epstein-Barr viral (EBV) genome was shown in specimens from the patient's nose, skin, and peripheral blood by in situ hybridization using an EBV-encoded small RNA-1 probe or by Southern blotting using a terminal-repeat probe of the EBV genome. Leukemic cells were cocultured with a mouse stromal cell line (SPY3-2) in the presence of 100 U/mL recombinant human interleukin-2 and a novel stromal cell-independent cell line, NK-YS, was established. The NK-YS cells showed LGL morphology and expressed surface CD2, CD5, CD7, CD25, CD56, and CD95. The NK-YS cells retained cytotoxicity against K562 and Jurkat cells. A Southern blotting using a terminal-repeat probe of EBV showed that NK-YS and fresh leukemic cells had a clonal EBV genome, whereas the T-cell receptor beta and gamma chain genes of NK-YS were not rearranged. In an immunocytochemical analysis, the NK-YS cells showed a type-II latent infection of EBV. The NK-YS cells preserved the original characteristics of NK cell lymphoma/leukemia and will be a useful tool for the study of biological characteristics of EBV-associated nasal angiocentric NK cell lymphoma/leukemia.

Adult↗
PubMed1998

Protein kinase C is involved in the regulation of both signaling and adhesion mediated by DNAX accessory molecule-1 receptor.

DNAX accessory molecule-1 (DNAM-1) is a signal-transducing adhesion molecule involved in the cytolytic function mediated by CTL and NK cells. In the present study, we have investigated various perimeters of DNAM-1-mediated signaling and adhesion. Although adhesion of DNAM-1 to its ligand does not require divalent cations, protein synthesis, or RNA transcription, activation of protein kinase C (PKC) is required for DNAM-1 functioning. Furthermore, mutation of the putative PKC-binding site in the cytoplasmic domain of DNAM-1 (Ser329 to Phe329) prevents both ligand binding and PMA-induced phosphorylation of the DNAM-1 receptor. These results indicate that PKC phosphorylates Ser329 of DNAM-1 and plays a critical role for both DNAM-1 adhesion and signaling.

Amino Acid Sequence↗
PubMed1998

Preparation of difluoro analogs of CCGs and their pharmacological evaluations.

All the stereoisomers of 2-(2-carboxy-3,3-difluorocyclopropyl)glycines (F2CCGs) were synthesized in enantiomerically pure forms using (R)-2,3-O-isopropyl-ideneglyceraldehyde as a chiral precursor. L-F2CCG-I, one of the stereoisomers corresponding to an extended form of L-glutamate was found to be a potent agonist for metabotropic glutamate receptors (mGluRs).

Amino Acids, Dicarboxylic↗
PubMed1998

Hepatitis G virus infection from needle-stick injuries in hospital employees.

A new RNA virus, hepatitis G virus (HGV) is known to be transmissible by blood transfusion. The aim of this study was to assess whether HGV is an occupational risk to hospital employees as a result of exposure to needle-stick injuries. Among 220 cases of needle-stick injuries, 21 employees were contaminated with HGV. Initially none of the 21 recipients were HGV positive. Fourteen of the 21 recipients were followed up and further tested for HGV RNA and serum anti-envelope (E2) specific antibody. None of the 21 recipients exposed to HGV developed liver function abnormalities, but one of the 14 recipients became positive for HGV RNA after the injury. Anti-E2 was negative in all recipients tested. These findings suggests a low clinical risk of occupational exposure to HGV in hospital employees. Nevertheless HGV is transmissible by needle-stick injury.

Acute Disease↗