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Biomedical subjects

H Tezuka

Publications and source records attributed to H Tezuka.

At least 73 records · Page 4Linked to original sources
PubMed1986

Evaluation of the mouse mutant "wasted" as an animal model for ataxia telangiectasia. I. Age-dependent and tissue-specific effects.

The wasted mouse, an animal model proposed for the genetically transmitted human disease ataxia telangiectasia (AT), was examined for its biological, cytogenetic and biochemical properties. In affected homozygotes, a marked age-dependent decrease in the ratio of spleen and thymus to body weight, and a slight but significant decrease in the liver to body weight ratio were observed while no such change was found in the kidney. An age-dependent increase was observed in the frequency of both spontaneous and gamma-ray-induced chromosomal aberrations in bone marrow cells of wasted mice. In littermate control mice, neither of these alterations was observed in an age-dependent manner. The activity of a primer activating enzyme, which has been reported to be deficient in AT cells, also decreased with age in spleen cells, but not in liver cells of affected mice. However, alterations in apurinic DNA endonuclease activity were not detected in the developmental stages examined. These data indicate that this mouse mutant may serve as a useful animal model for studying the relationships between DNA repair and lymphoid tissue differentiation.

Aging↗
PubMed1986

Physiopathological studies on granulocyte-macrophage colony stimulating factor and multi colony stimulating factor producing leukemia, L8313, induced by irradiation of C3H mice.

Radiation-induced L8313 leukemia bearing mice (L8313 mice) had marked granulocytosis with splenomegaly. Hemopoietic stem cells and progenitors increased in the spleen but not in the bone marrow. Spleen conditioned-medium and serum from L8313 mice induced the formation of granulocyte-macrophage colonies (CFU-GM), erythroid bursts (BFU-E) and mixed colonies (CFU-Mix). Bone marrow conditioned medium did not show such activity. A cell line (STIL-3) was established from the spleen cells of L8313 mice. Surface marker analysis showed that the established cells were suppressor T cell. The cells produced IL-3 and GM-CSF in vitro, and induce essentially the same "leukemic" response in recipient mice. Inoculation of STIL-3 in diffusion chamber also induced leukemoid reaction, i.e. a marked granulocytosis with splenomegaly. Therefore, L8313 leukemia may be linked to an abnormality of growth and production of hemopoietic factors in hemopoietic regulatory cells.

Animals↗
PubMed1986

Class II major histocompatibility complex antigen expression and cellular interactions in thyroid glands of Graves' disease.

Class II major histocompatibility complex (MHC) antigens have been demonstrated on the surface of thyroid epithelial cells (thyrocytes) from patients with autoimmune thyroid disease. The present study was designed to investigate how the expression of class II MHC antigens is involved in autoimmune processes in Graves' disease by studying cellular interactions among thyrocytes, lymphocytes within thyroid glands (TG), and peripheral blood (PB) lymphocytes. Thyrocytes were prepared by collagenase digestion, and T or non-T cells were separated by E-rosette formation. Thyrocytes were cocultured in the presence or absence of interferon-gamma, and the expression of HLA-DR antigens on cultured thyrocytes was examined by an indirect immunofluorescence method using monoclonal anti-HLA-DR antibody and monoclonal anti-HLA-DQ antibody. The cellular interactions were assessed as the proliferative response of T cells to autologous stimulators, such as thyrocytes or lymphocytes. Expression of HLA-DR antigens on thyrocytes after culture for 18 h in the absence of interferon-gamma was found in two thirds of the patients with Graves' disease studied (n = 18). Interferon-gamma induced and maintained the expression of HLA-DR antigens on thyrocytes. The percentages of HLA-DR+T cells were significantly higher among TG-T cells than among PB-T cells [32.6 +/- 12.4% (+/- SD) vs. 12.2 +/-5.0%; n = 18; P less than 0.01]. Thyrocytes from Graves' patients induced proliferation of both autologous PB-T cells and TG-T cells, and TG-T cells stimulated proliferation of autologous PB-T cells. In conclusion, interferon-gamma induces HLA-DR antigen expression on thyrocytes from patients with Graves' disease, and these cells induce proliferation of autologous T cells, which may, in turn, act on thyrocytes to perpetuate the process.

Adolescent↗
PubMed1986

Effect of DNA-damaging agents on isolated spleen cells and lung fibroblasts from the mouse mutant "wasted," a putative animal model for ataxia-telangiectasia.

Spleen cells from control and wasted (wst) mice, a putative animal model for the human genetic disease ataxia-telangiectasia, were tested for inhibition of replicative (semiconservative) DNA synthesis after treatments with bleomycin, gamma-irradiation, 4-nitroquinoline 1-oxide, and ultraviolet irradiation. The wasted cells were found to be more resistant than control cells to the first three treatments, but equally sensitive to ultraviolet light. Bleomycin-stimulated repair synthesis in spleen cells was also studied by the CsCl/bromodeoxyuridine method and found to be similar in cells from wasted and control animals. Similarly, no differences in sensitivity to killing by gamma-rays, as manifested by relative cloning efficiencies, were demonstrated between primary lung fibroblasts from mutant and control mice. We concluded that observed defects in DNA repair in wasted cells are not identical to those reported in human cells from ataxia-telangiectasia patients.

4-Nitroquinoline-1-oxide↗
PubMed1986

Effect of colony-stimulating factor-producing tumor on hemopoiesis in splenectomized mice.

The colony-stimulating factor-producing BMA-1 tumor was transplanted into splenectomized mice. These mice showed as much granulocytosis as non-splenectomized mice bearing the tumor. The increase in the number of peripheral leukocytes induced per tumor weight was similar in the two groups. The hemopoietic cell population in the central bone marrow (tibia) was not increased by splenectomy. The total numbers of spleen colony-forming cells and granulocyte-macrophage colony-forming cells in the whole body of tumor-bearing splenectomized mice were 29% and 58% of those in the tumor-bearing non-splenectomized mice, respectively. The expansion of hemopoiesis to the peripheral bone marrow in tumor-bearing splenectomized mice was confirmed by histological examination of the tail bone. These results suggest that the lack of increase in the bone marrow cellularity is due to the space limitation, and that this is well compensated for by a great expansion of hemopoietic marrow to the peripheral bones in splenectomized mice.

Animals↗
PubMed1986

Effects of splenectomy on the retention of Salmonella enteritidis and on the hemopoietic response to Salmonella infection.

Salmonella infection induces a marked increase in the splenic granulopoiesis, but causes a reduction in hemopoiesis in the bone marrow. In this study, effects of Salmonella enteritidis infection on hemopoietic stem cells were examined in splenectomized (SX-) mice. Splenectomy emphasized hemopoietic damage in the bone marrow caused by Salmonella infection. Total nucleated cells, pluripotent stem cells (CFUs) and granulocyte-macrophage progenitor cells (GM-CFC) in the bone marrow of SX-mice all decreased markedly compared with sham-splenectomized (NX-) mice, and the recovery from the decline was also delayed. Thus, neither enhancement of the granulopoiesis nor granulopoietic recovery in the bone marrow was observed to compensate the granulopoietic response in the spleen. Splenectomy also resulted in a longlasting retention of Salmonella in the liver. The observations indicate that the spleen is the major organ to respond to bacterial invasion in regard to enhanced granulopoiesis and hence enhanced bacterial clearance.

Animals↗
PubMed1985

Complete nucleotide sequence of a gene coding for heat- and pH-stable alpha-amylase of Bacillus licheniformis: comparison of the amino acid sequences of three bacterial liquefying alpha-amylases deduced from the DNA sequences.

The gene coding for the heat-stable and pH-stable alpha-amylase of Bacillus licheniformis 584 (ATCC 27811) was cloned in Escherichia coli and the nucleotide sequence of a DNA fragment of 1,948 base pairs containing the entire amylase gene was determined. As inferred from the DNA sequence, the B. licheniformis alpha-amylase had a signal peptide of 29 amino acid residues and the mature enzyme comprised 483 amino acid residues, giving a molecular weight of 55,200. The amino acid sequence of B. licheniformis alpha-amylase showed 65.4% and 80.3% homology with those of heat-stable Bacillus stearothermophilus alpha-amylase and relatively heat-unstable Bacillus amyloliquefaciens alpha-amylase, respectively. Nevertheless, several regions of the alpha-amylases appeared to be clearly distinct from one another when their hydropathy profiles were compared.

Amino Acid Sequence↗
PubMed1985

Phenotypic analysis of acute lymphoblastic leukemia (ALL) cells which are classified as non-T non-B and negative for common ALL antigen.

When phenotypic marker analysis of acute lymphoblastic leukemia (ALL) cells (102 cases) was performed, a group of ALL cells (15 cases) classified as non-T non-B, and negative for common-ALL antigen (CALLA) was characterized in a focused manner. "Non-T non-B" was defined as negative for T cell properties such as E-rosetting or reactivity with anti-human T-cell monoclonal antibodies (T101, WT1), and absence of any B-cell characteristics (cell surface and/or cytoplasmic immunoglobulin and reactivity with B1 monoclonal antibody). Despite their marked heterogeneity, CALLA(-) non-T non-B ALL cells revealed three different phenotypic patterns in terms of presence of terminal deoxynucleotidyl transferase (TdT) and of reactivity with antimyeloid (MCS1) or myelomonocyte (MCS2 and OKM1) monoclonal antibodies. Four of 15 cases reacted with some myeloid-specific antibodies, but were negative for TdT. Six cases had both MCS2 antigen and TdT. The remaining five cases expressed no myeloid antigens, but were positive for TdT with some exceptions. These findings showed that acute leukemias with myeloid antigens might be involved in CALLA(-) non-T non-B ALL having no relationship to the presence of TdT, and, furthermore, that the blasts with simultaneous expression of TdT and myeloid-specific antigen (MCS2) might represent an immature stage in hematopoietic differentiation closely corresponding with the bifurcation of the lymphocyte/myeloid pathway. Alternatively, only five cases remained "unclassified leukemia." We therefore think that the detailed examination of CALLA(-) non-T non-B ALL cells using myeloid specific antibodies is helpful in clarifying the characteristics of myeloid precursors and the common bipotential stem cell of lymphoid and myeloid progenitors.

Adult↗