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Biomedical subjects

S Taniguchi

Publications and source records attributed to S Taniguchi.

At least 379 records · Page 21Linked to original sources
PubMed1993

Promotion of survival and proliferation by interleukin 3, kit-ligand and erythropoietin on early and late appearing spleen colony forming units in culture.

We examined the effects of interleukin 3 (IL-3), kit-ligand and erythropoietin (EPO) on the survival and growth of early appearing spleen colony forming units (CFU-S8) and late appearing CFU-S (CFU-S12) in short-term liquid culture (SLC). In the control cultures, without any additive, CFU-S8 and CFU-S12 declined; nearly 10% of the initial number of CFU-S still survived by the second day of culture. The addition of IL-3 or kit-ligand increased the survival both of CFU-S8 and CFU-S12, with an increased dose of concentration, at final concentrations of 10-200 U/ml and 500-50x dilution, respectively. However, only the survival of CFU-S8 increased when EPO was added up to 10 U/ml, while the frequency of CFU-S12 was not higher than in the control culture. The percentage of CFU-S8 and CFU-S12 in DNA synthesis, evaluated in 3H-TdR cytocide experiments, increased after one day in culture with each of the three factors. The results suggest that all three factors stimulated the proliferation of both populations of CFU-S, but the two populations showed different patterns of response to each factor; EPO stimulates the proliferation of CFU-S12 that differentiate into CFU-S8 that have less capacity for self-renewal, while the addition of IL-3 or kit-ligand causes an increase in the number of both populations due to the stimulation of an earlier stage of stem cell differentiation or self-renewal of CFU-S12. Our experimental system (SLC-CFU-S assay) is useful for evaluating the response of hematopoietic stem cells to cytokines which promote the in vitro survival and proliferation of these cells.

Animals↗
PubMed1993

A chicken homeobox gene related to Drosophila paired is predominantly expressed in the developing limb.

We identified a homeobox-containing gene, Prx-1, isolated from the chick limb bud cDNA library. The homeodomain sequence is related to Drosophila paired and goose-berry and mouse Pax-3, Pax-6, and Pax-7. The deduced amino acid sequence of the Prx-1 gene product reveals the absence of a paired-box sequence and extensive similarity to mouse S8 and MHox homeodomain proteins, thus constituting a new class of homeobox gene. Using an in situ hybridization method, the Prx-1 gene is shown to be expressed predominantly in the limb bud and visceral arches. At early stages of limb development, distal mesodermal cells express the homeobox gene with an apparent gradient along the proximal-distal axis. The signal is absent in the apical and nonridge ectoderm. Removal of the apical ectodermal ridge had no apparent effect on the subsequent expression of Prx-1 in the limb mesenchyme. The Prx-1-expressing cells are later confined to the interdigital and perichondrial regions. The Prx-1 transcripts are also detectable in the mesenchyme of the visceral arches and facial primordia subjacent to the ectoderm. The Prx-1 gene is weakly expressed in somites and condensing vertebrae. No signal is detectable in neural tube and ectodermal epithelium. These results suggest that the Prx-1 homeodomain protein is involved in the differentiation of bone, muscle, and other tissues of mesodermal origin during limb development.

Amino Acid Sequence↗
PubMed1993

Expression of alpha-smooth muscle actin in benign or malignant ovarian tumors.

We compared the expression of alpha-smooth muscle actin (alpha-SMA) between benign and malignant human ovarian tissues by immunohistochemical staining and Western blot analysis using the monoclonal antibody specific to alpha-SMA. In normal human ovaries, alpha-SMA was found in the blood vessel walls, muscle fibers, and stromal cells surrounding the follicles. The main source of alpha-SMA in the benign ovarian tumors was the blood vessel walls which highly expressed the alpha-SMA throughout the tumor. In malignant tumor tissues, however, the vessels located in or close to the cluster of cancer cells did not express alpha-SMA. It corresponded to the results of the Western blot analysis, showing that the amount of alpha-SMA in malignant ovarian tumor tissues was much smaller than that in benign tumor tissues. Thus, the alteration in alpha-SMA expression seems to reflect the qualitative difference in vessels between benign and malignant ovarian tissues, and therefore alpha-SMA is considered to potentially be a histopathologically useful marker for indicating the malignant potential of ovarian tumors.

Actins↗
PubMed1993

A structurally flexible and antigenically variable N-terminal domain of the hepatitis C virus E2/NS1 protein: implication for an escape from antibody.

Hepatitis C virus persists in most infected hosts, and causes chronic hepatitis, liver cirrhosis, and/or hepatocellular carcinoma in humans. During the infection the RNA genome of hepatitis C virus undergoes frequent missense mutations at one or two "hypervariable" regions within a presumptive envelope gene (Okamoto et al., 1992, Virology 190, 894-899; Ogata et al., 1991, Proc. Natl. Acad. Sci. USA 88, 3392-3396). In the present study, we analyzed three cases of hepatitis C virus infection, two in chimpanzees and one in humans, for the antigenicity of peptides predicted from the hypervariable region of viral RNA obtained during the follow-up. Our results showed a successive appearance of hepatitis C virus mutants with antigenically distinct amino acid sequence within the domain; and the amino acid replacement was associated with an alteration of predicted local secondary structure of the epitope region. Hence, the hypervariable domain of the hepatitis C virus envelope appeared to be structurally flexible and antigenically variable, providing the virus a way to escape from host immunity.

Amino Acid Sequence↗
PubMed1993

Effect of parathyroid hormone on acid/base transport in rabbit renal proximal tubule S3 segment.

The effect of parathyroid hormone (PTH) on acid/base transport in isolated rabbit renal proximal tubule S3 segment was investigated with double-barreled and conventional microelectrodes. PTH (10 nM) induced a small depolarization and enhanced the initial rates of cell pH (pHi) increase and cell Cl- ([Cl-]i) decrease in response to bath Cl- removal by 28.0 +/- 2.1% and 31.0 +/- 6.4% respectively. The calculated initial HCO3- influx to bath Cl- removal was also enhanced by 28%. On the other hand, PTH reduced the initial rate of pHi decrease to luminal Na+ removal in the absence of HCO3-/CO2 by 20.4 +/- 3.9%. The PTH-induced depolarization was not accompanied with changes in steady-state pHi or [Cl-]i levels, but was greatly attenuated in the presence of ouabain (0.1 mM). Either dibutyryl-cAMP (0.1 mM) plus theophylline (1 mM) or forskolin (10 microM) alone could reproduce all the effects of PTH. These results indicate that (a) PTH inhibits the luminal Na+/H+ exchanger but stimulates the basolateral Cl-/HCO3- exchanger in the S3 segment; (b) the PTH-induced depolarization largely results from inhibition of Na+/K(+)-ATPase and (c) all these effects are at least partly mediated by a cAMP-dependent mechanism.

Animals↗
PubMed1993

Lower extremity ischemia secondary to internal thoracic-coronary artery bypass grafting.

Vascular complications associated with the use of the internal thoracic artery as a conduit for coronary artery bypass are infrequent. However, acute limb-threatening ischemia can occur after the use of the internal thoracic artery for myocardial revascularization when this vessel forms an important collateral to an obstructed aortoiliac artery system. Although this is a rare complication, the consequences are devastating. Due to the risk of peripheral vascular insufficiency, we now perform simultaneous revascularization of the myocardium and the lower extremity when an internal thoracic artery that appears to be a major collateral to the ipsilateral aortoiliac system is used.

Acute Disease↗
PubMed1993

The effect of N-myc amplification and expression on invasiveness of neuroblastoma cells.

Most neuroblastomas with N-myc amplification, a sign of extremely poor prognosis, are extensively invasive to surrounding tissues. Therefore, we investigated the relationship between N-myc amplification and invasiveness of neuroblastoma cells, using an in-vitro assay system. Five human neuroblastoma cell lines were used for this study. IMR-32, GOTO, and DZ, all of which had N-myc amplification, showed a highly invasive capacity. In contrast, SK-N-SH without N-myc amplification showed extremely low invasiveness. ST unexpectedly showed high invasiveness in spite of the lack of N-myc amplification. Treatment of GOTO with 10(-5) mol/L all-trans-retinoic acid (RA) for 72 hours markedly decreased both N-myc expression and invasiveness. Treatment of GOTO with 2 mmol/L dibutyryl cyclic AMP (dbcAMP) for 72 hours caused a slight decrease of N-myc expression and invasiveness. These results indicate that N-myc amplification and expression might be closely related to the invasiveness of human neuroblastoma cells.

Cell Movement↗
PubMed1993

B-lymphoid/myeloid stem cell origin in Ph-positive acute leukemia with myeloid markers.

We report two cases of Philadelphia chromosome (Ph)-positive acute leukemia with definite myeloid markers. Ph was the sole chromosomal abnormality at presentation, and neither eosinophilia, basophilia, thrombocytosis nor hepatosplenomegaly was present. In both cases, Ph+ myeloblasts showed positive stain for myeloperoxidase and naphthol ASD chloroacetate esterase, which fulfilled the FAB criteria of acute myelogenous leukemia (AML). Ph+ myeloblasts co-expressed myeloid and B-lymphoid antigens (CD10, CD13, CD19 and CD33). In case 1, myeloblasts rearranged M-BCR, and the expression of M-BCR/ABL chimeric RNA was demonstrated by using the reverse transcription polymerase chain reaction (RT-PCR). They also clonally rearranged IGH. Ph clone disappeared on cytogenetic analysis in remission, and granulocytes in remission did not have rearranged M-BCR. In case 2, morphocytochemically distinct myeloid and lymphoid blast populations were seen. Myeloblasts and lymphoblasts were enriched > 96% as CD19-/CD33+ and CD19+/CD33- populations, respectively. Both of them possessed the identical rearrangement of IGH and M-BCR, indicating a common leukemic progenitor cell origin. Furthermore, m-BCR/ABL was detected in addition to M-BCR/ABL on RT-PCR. Accordingly, both cases were diagnosed as de novo Ph+ acute leukemia rather than as chronic myelogenous leukemia in blastic crisis. Their mixed B-lymphoid/myeloid characteristics strongly suggest that so-called 'Ph+ AML' is derived from Ph+ myeloid/B-lymphoid stem cells.

Adolescent↗
PubMed1993

Colony promoting activity (CPA) is a novel factor distinct from IL-6.

The supernatant (CM) of long-term bone marrow culture (LTBMC) contains colony promoting activity (CPA) which does not have granulocyte-macrophage (GM) colony-stimulating activity but which enhances GM-colony formation in the presence of CSF. CPA is different from IL-1, IL-3 and GM, G-, and M-CSF. Since CPA-containing LTBMC-CM always contains a substantial level of IL-6, CPA was thought to be similar to IL-6. In the present study, we found that LTBMC with a particular batch of horse serum produced IL-6 without a corresponding production of CPA. Addition of IL-6 to GM-colony assay system in the presence of GM-CSF did not enhance the colony formation. LTBMC-CM did not stimulate proliferation nor differentiation of mast cell progenitors. Anti-IL-6 antibodies suppressed IL-6 activity, but not CPA. These results indicate that CPA is a novel factor distinct from IL-1, IL-3, G-, M-, GM-CSF, IL-6 and SCF (c-kit ligand).

Animals↗
PubMed1993

A combined therapeutic modality with hyperthermia and locally administered rIFN-beta inhibited the growth of B16 melanoma in association with the modulation of cellular infiltrates.

Murine B16-F10 melanoma was treated with local microwave hyperthermia, local injection of murine recombinant interferon-beta (rIFN-beta) or a combination of both in order to investigate the augmentation of anti-proliferative effects with this combination treatment. Concerning the local modulation of immunological reactions of the host, local hyperthermia at 43 degrees C for 15 min on murine melanoma caused remarkable infiltration of natural killer cells and local injection of rIFN-beta led to considerable infiltration of T cells. When these two modalities were combined, the infiltration of NK cells completely disappeared and, instead, remarkable augmentation of T cell infiltration occurred. Synergistic suppressive effects on melanoma growth with occasional scar formation were seen with this combined modality. These results indicate that local hyperthermia with a combination of rIFN-beta modulates local immune reactions of the host, and probably this immune reaction is partly involved in the course of the suppression of tumor growth.

Animals↗
PubMed1993

A mutation in the Pax-6 gene in rat small eye is associated with impaired migration of midbrain crest cells.

The rat small eye strain (rSey) lacks eyes and nose in the homozygote, and is similar to the mouse Sey strain with mutations in the Pax-6 gene. We isolated Pax-6 cDNA clones from an rSey homozygote library, and found an internal deletion of about 600 basepairs in the serine/threonine-rich domain. At the genomic level, a single base (G) insertion in an exon generates an abnormal 5' donor splice site, thereby producing the truncated mRNA. Anterior midbrain crest cells in the homozygous rSey embryos reached the eye rudiments but did not migrate any further to the nasal rudiments, suggesting that the Pax-6 gene is involved in conducting migration of neural crest cells from the anterior midbrain.

Alternative Splicing↗
PubMed1993

An efficient gene-trap method using poly A trap vectors and characterization of gene-trap events.

New trap vectors (U1 and U2) have been developed to trap genes in murine embryonic stem (ES) cells. The polyA addition signal of the neomycin phosphotransferase II (neo) gene was removed from these vectors so that they needed to trap an endogenous polyA signal for expression of the neo gene. The frequency of gene-trap events of these vectors was about five times higher than with the vector containing the polyA signal, and only one copy of the trap vector was integrated in most cases. Four out of five 5'-flanking regions of the integrated vector in ES cell lines were found to be novel endogenous promoters, suggesting that this method is efficient for trapping genes in ES cells. In two cases analyzed, large deletions or rearrangements spanning more than 10 kb were found in the 3'-flanking region of the trap vector introduced by electroporation. This result suggests that phenotypes observed in homozygotes with a mutated allele could be due to the disruption of a gene adjacent to the trapped gene, but not of the trapped gene.

Animals↗
PubMed1993

Effects of ultraviolet-B and PUVA on ornithine decarboxylase activity, DNA synthesis, and protein kinase C activity in mouse skin.

Ultraviolet-B and PUVA share several biological events with phorbol ester tumor promoters. The effects of ultraviolet-B irradiation and topical PUVA treatment on ornithine decarboxylase activity, DNA synthesis, and protein kinase C activity, which are known to be induced or activated by phorbol ester tumor promoter, were investigated in hairless mouse skin. Ornithine decarboxylase activity was remarkably enhanced by ultraviolet-B and PUVA. Although PUVA did not affect DNA synthesis significantly, ultraviolet-B stimulated epidermal DNA synthesis approximately 5-fold over control values at 48 h. However, unexpectedly, neither cytosolic nor membrane-bound protein kinase C activity showed any change during the 2 h after either treatment. These results suggest that the protein kinase C system is not involved in the initial signal transduction system of ultraviolet-B or PUVA, unlike the case with phorbol ester tumor promoter.

Animals↗
PubMed1993

Detection of human T-cell lymphotropic virus type-1 proviral DNA in the saliva of an adult T-cell leukaemia/lymphoma patient using the polymerase chain reaction.

We report a case of adult T-cell leukaemia/lymphoma (ATLL), in whom the polymerase chain reaction (PCR) on genomic DNA from saliva demonstrated the monoclonal integration of human T-cell lymphotropic virus type-1 (HTLV-1) proviral DNA in lymphocytes in the saliva. These results provided evidence of the possibility of saliva-borne transmission of HTLV-1.

Base Sequence↗
PubMed1993

Spontaneous remission of acute adult T-cell leukaemia with chromosomal abnormality infiltrating to skin and liver.

Acute type of adult T-cell leukaemia (ATL) has been recognized as highly-progressive T-cell malignancy with a median survival of 7 months. We present a case who had a spontaneous remission from acute type ATL with organ involvement and chromosomal abnormality implying very poor prognosis. Although the mechanism of spontaneous remission remains uncertain, our case was unique with regard to the progression and regression of leukaemia.

Chromosome Aberrations↗
PubMed1993

Decreased levels of myeloid progenitor cells associated with long-term administration of recombinant human granulocyte colony-stimulating factor in patients with autoimmune neutropenia.

We studied the long-term in vivo effect of recombinant human granulocyte colony stimulating factor (rhG-CSF) on in vitro growth of granulocyte/macrophage colony forming cells (GM-CFC) in bone marrow and peripheral blood obtained from two patients with autoimmune neutropenia, who received rhG-CSF. Along with rhG-CSF treatment for more than 40 d, numbers of GM-CFC-derived colonies from both bone marrow and peripheral blood gradually decreased to a significant level though white blood cells in peripheral blood and nucleated cells in bone marrow were increased in number. This observation suggests that long-term administration of rhG-CSF may preferentially activate a differentiation pathway for granulopoiesis while proliferation of GM-CFC is not induced as expected in response to rhG-CSF.

Aged↗