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Y Yazaki

Publications and source records attributed to Y Yazaki.

At least 523 records · Page 29Linked to original sources
PubMed1995

[Successful treatment of splenomegaly and anemia by VP therapy in idiopathic myelofibrosis complicated with acromegaly: a case report].

Here we report a 65-year-old male patient with idiopathic myelofibrosis (IMF) accompanied with acromegaly. He was admitted because of anemia and splenomegaly. No favorable effects were observed when hydroyurea was administered. However, his symptoms were successfully treated by administration of vincristine and prednisolone (VP therapy), which is usually applied for choronic myelogenous leukemia in the accelerated phase. Therefore, VP therapy might be one possible for IMF. Since there have been several reports suggesting the possible association of hematological malignancies with acromegaly, we speculate that acromegaly was implicated in the initiation or progression of IMF in this case.

Acromegaly↗
PubMed1995

Determination of mRNA levels of cholesterol biosynthesis enzymes and LDL receptor using ribonuclease protection assay.

We designed a rapid method for determining mRNA content of cholesterol biosynthesis enzymes and LDL receptor (LDLR) using a ribonuclease protection assay (RPA). 32P-labeled cRNA fragments for genes of human LDLR and the enzymes HMG-CoA synthase (HMGS), HMG-CoA reductase (HMGR), mevalonate kinase (MK), farnesyl pyrophosphate synthase (FPPS), and squalene synthase (SQS) were prepared by in vitro transcription. Total RNA prepared from HepG2 cells was hybridized with the cRNA probe and the hybridized mRNA was determined under protection from RNase digestion. Probe content used in this assay was excess in determining the desired mRNA in total RNA, and surplus probes were completely digested using RNase under standard conditions. When cells were cultured in DMEM supplemented with 10% fetal calf serum (FCS), mRNA levels of FPPS, SQS, and LDLR were about 4- to 7-fold higher than those of HMGS, HMGR, and MK. On incubation with DMEM supplemented with 10% lipoprotein-deficient serum (LPDS) for 8 h, all messenger RNA levels increased 1.5- to 3.5-fold. In addition, when the HMG-CoA reductase inhibitor compactin was added to 10% LPDS-DMEM, these levels increased even further and the change in mRNA level seemed to differ between the enzymes and LDLR. From these results, we conclude that RPA is a useful method for determining the very small amount of mRNA level of cholesterol biosynthesis enzymes and LDLR in the cell.

Base Sequence↗
PubMed1995

The 5' coding sequence of IL-2 receptor alpha chain mRNA mediates mRNA stabilization by HTLV-1 Rex.

The interleukin-2 receptor alpha chain (IL-2R alpha) is a T-cell growth factor receptor and is known to be induced in helper T cells by infection with human T-cell leukaemia virus type-1 (HTLV-1). The Rex protein of HTLV-1 has been shown to stabilize IL-2R alpha mRNA. Although the 3' untranslated region of many RNA has been regarded as a key element for stabilization, we found that the first 300 bases of the IL-2R alpha protein coding sequence were necessary for stabilization of the mRNA. As the first 201 bases were not sufficient for this effect, we conclude that the bases at position 201-300 downstream of the AUG start are important for stabilization.

Cell Culture Techniques↗
PubMed1995

Impaired development of the thyroid and thymus in endothelin-1 knockout mice.

We have previously demonstrated that endothelin-1 (ET-1) is essential to the development of neural crest-derived craniofacial and cardiovascular structures. In this study we evaluated the intrauterine growth and development of the thyroid and thymus glands in Edn1-/- homozygous mice. Edn1-/- homozygous mice were smaller than their heterozygous or wild-type littermates (about 90% of normal body weight). The thyroid and thymus of Edn1-/- homozygous mice were smaller than those of normal mice and were not fused in the midline, resulting in two separate lobules. The thymus of Edn1-/- homozygous mice is not descended into the normal position. These results suggest that ET-1 is important for normal development of the glands in the neck region, as well as for systemic growth. The combination of abnormalities in Edn1-/- homozygous mice suggests that these mice might serve as an animal model for the human diseases DiGeorge syndrome and velocardiofacial syndrome.

Animals↗
PubMed1995

Gene expression of endothelin isoforms and receptors in endothelin-1 knockout mice.

Gene expression of endothelin (ET) isoforms and receptors was examined in ET-1 knockout mice and compared with that of wild-type mice. ET-1 mRNA and peptide levels were in parallel with the number of Edn1 authentic alleles. ET-2 mRNA levels in intestine and ET-3 mRNA and/or peptide levels in lung, brain, and intestine were not different among Edn1+/+ wild-type, Edn1+/- heterozygous, and Edn1-/- homozygous mice. ET(A) and ETB receptor mRNA levels in several organs also were not different among Edn1+/+ wild-type, Edn1+/- heterozygous, and Edn1-/- homozygous mice. These results suggest that gene expression of ET-2, ET-3, and ET(A/B) receptors is not affected by levels of ET-1 production and is regulated independently. Neither compensation by redundant expression of other ET isoforms nor upregulation of ET receptors could explain the elevated blood pressure in Edn1+/- heterozygous mice.

Animals↗
PubMed1995

[Troponin T].

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Biomarkers↗
PubMed1995

Localization of sulfatides in the epithelial lining of gastric mucosa: studies with a monoclonal antibody to sulfatides.

A specific monoclonal antibody against sulfatides was used to examine the cellular localization of sulfatides, the most predominant acidic glycosphingolipids in both rabbit and human gastric mucosa. The monoclonal antibody selectively recognized sulfatides among the acidic glycolipids extracted from rabbit gastric mucosa. Immunofluorescence staining revealed that specific staining was localized in the epithelial cells of the stomach. Both epithelial and glandular cells were stained in the fundic mucosa. In human stomach, the staining pattern was essentially identical to that in rabbit stomach. The specific localization of sulfatides in the epithelial lining supports our hypothesis that they may be a component of mucosal defensive substances and an adhesion receptor for Helicobacter pylori.

Animals↗
PubMed1994

Characterization, partial purification, and peptide sequencing of p130,the main phosphoprotein associated with v-Crk oncoprotein.

The transforming gene v-crk found in CT10 and ASV-1 avian sarcoma viruses induces marked phosphorylation of several proteins in cells expressing p47v-crk (v-Crk). In this work, the main tyrosine-phosphorylated proteins in ASV-1-infected chicken cells and v-crk-transfected rat cells were characterized biochemically. Both these proteins have a molecular mass of about 130 kDa and are tightly associated with v-Crk in vivo. Two-dimensional gel electrophoresis revealed that they are both essentially single proteins (p130) with modifications that result in a broad spot in an acidic region. The broad band of semi-purified p130 became sharp at an elevated position in the gel upon treatment with orthovanadate in vivo or with c-Src kinase produced using a baculovirus vector in vitro, whereas it shifted at a lower position upon treatment with alkaline phosphatase in vitro. These results suggest multiple phosphorylation states of p130, which result in a broad band of p130. Two procedures of immunoaffinity purification were used to purify p130 from 3Y1 cells transfected with v-crk. Approximately 30 pmol of purified p130 was obtained in an immobilized form on a filter starting from 3 x 10(10) cells. Peptide mapping of p130 digested in situ by peptidase revealed that the purity and quantity of the final material were enough for peptide sequencing. Several stretches of partial amino acid sequences were determined, and they indicated that p130 is a novel protein.

Amino Acid Sequence↗
PubMed1994

Immunosuppression to cardiac allografts and soluble antigens by anti-vascular cellular adhesion molecule-1 and anti-very late antigen-4 monoclonal antibodies.

Effective activation of T cells in immune responses depends on two signals, one from the CD3/TCR complex and another from accessory cell surface proteins. Very late Ag-4 (VLA-4) can exert a costimulatory function upon binding with vascular cellular adhesion molecule-1 (VCAM-1). We investigated the effects of mAbs against VCAM-1 and VLA-4 on cardiac allograft survival and humoral response to soluble Ags. BALB/c hearts were transplanted into C3H/He recipients. mAbs (100 micrograms/day) were administered i.p. for the first 6 days. Graft survival in mice treated with M/K-2 (anti-VCAM-1; median survival: 20 days, n = 6) and those treated with PS/2 (anti-VLA-4; 30 days, n = 6) was greater than that in control mice (8 days, n = 7). Eight of 18 mice treated with both M/K-2 and PS/2 accepted the grafts over 65 days, and five of them accepted the grafts over 100 days. Allografts treated with the two mAbs showed scattered infiltration of leukocytes without evidence of active rejection at 65 days. Mice with long-surviving cardiac grafts were challenged with skin grafts from donor and third-party (C57BL/6) strains. Survival of the donor-type skin was significantly greater than that of the third-party skin. One mouse specifically accepted the donor-type skin indefinitely (> 150 days). FACS analysis of splenocytes at 55 days after transplantation showed complete recovery of VLA-4 expression from a down-regulation observed at day 7. In addition, mice immunized with heat-aggregated human gamma-globulin did not produce specific Ab, even after boost immunization, if PS/2 was administered at the time of the first immunization. This unresponsiveness to xenogeneic protein lasted for more than 50 days. These results indicate that in vivo administration of anti-VCAM-1 and anti-VLA-4 mAbs induces specific immunosuppression to cardiac allografts and soluble Ags.

Animals↗
PubMed1994

Molecular cloning, characterization, and chromosomal localization of a novel protein-tyrosine phosphatase, HPTP eta.

Protein-tyrosine phosphatases (PTPases) are considered to play an important role in signal transduction. We previously identified partial sequences of three novel PTPases in a human leukemic cell line. F-36P. We describe here cloning, characterization, and chromosomal localization of one of the newly identified PTPases, termed as HPTP eta (human protein-tyrosine phosphatase eta). The deduced amino acid sequence was composed of an extracellular region homologous to fibronectin type III repeats, a transmembrane region, and a cytoplasmic region containing a single PTPase-like domain. Based on its primary structure, this clone belongs to type-III receptor-type PTPases. The PTPase-like domain showed PTPase activity when expressed in Escherichia coli. Antibody against the extracellular region detected a protein of 220 to 250 kD in human hematopoietic cell lines expressing HPTP eta mRNA. The antibody also recognized a protein of approximately the same molecular weight in COS cells transfected with HPTP eta cDNA, indicating that the antibody specifically recognized HPTP eta gene product and that the cloned cDNA contained full-length coding region. The chromosomal localization determined by fluorescence in situ hybridization showed that the HPTP eta gene was located at chromosome 11p11.2 on the short arm of chromosome 11, which is frequently lost or deleted in human carcinomas.

Amino Acid Sequence↗
PubMed1994

Regulation of low density lipoprotein receptor activity in Chinese hamster ovary cells transfected with the c-fms gene.

Chinese hamster ovary (CHO) cells were transfected with the human c-fms gene, which encodes the receptor for macrophage colony-stimulating factor, to examine the effects on the low density lipoprotein (LDL) receptor activity. Degradation of [125I]LDL was significantly reduced in the transfected CHO cells as compared to non-transfected cells when incubated in lipoprotein-deficient serum. Quantitative analysis of LDL receptor mRNA using a competitive PCR method demonstrated that LDL receptor suppression occurred at transcription. These findings suggest that expression of the c-fms gene is involved in the regulation of LDL receptors on macrophages.

Animals↗
PubMed1994

Homozygous loss of the cyclin-dependent kinase 4-inhibitor (p16) gene in human leukemias.

Recently, it has been shown that the homozygous deletion of the cyclin-dependent kinase-4 inhibitor (CDK4I;p16) gene, which is mapped to chromosome 9p21, is frequently observed in a wide spectrum of human cancers, including leukemias. Therefore, the CDK4I gene is thought to be a putative tumor-suppressor gene. We report here that both alleles of the CDK4I gene were completely or partially deleted in human leukemia cells derived from both patients and established cell lines. Thirty-seven hematopoietic cell lines and samples from 72 patients with leukemias were examined for homozygous loss of the CDK4I gene locus by Southern blot analysis. We found that a part or the whole of the CDK4I gene was homozygously deleted in 14 of the 37 (38%) cell lines and 4 of 72 (6%) samples from leukemia patients, including 45 with acute myelocytic leukemia, 14 with acute lymphocytic leukemia (ALL), and 13 with chronic myelocytic leukemia in blastic crisis. In the cell lines, the homozygous deletion of the CDK4I gene was detected in a variety of cell lineages, whereas all 4 cases showing the homozygous deletion were confined to ALL. It should be noted that 2 of them had no cytogenetic abnormalities of chromosome 9. Our results suggest that loss of the CDK4I function may contribute to immortalization of human leukemia cells and play a causative role at least in development of human lymphocytic leukemias.

Adult↗
PubMed1994

Molecular cloning and characterization of a cDNA for bovine phospholipase C-alpha: proposal of redesignation of phospholipase C-alpha.

We have isolated bovine phospholipase C (PLC)-alpha cDNA from bovine thymus. Sequence analysis showed that PLC-alpha is highly conserved among rat, mouse, and calf and that it has two Trp-Cys-Gly-His-Cys-Lys motifs completely conserved in the mammals. Southern blot analysis revealed that bovine PLC-alpha is derived from a single gene. When PLC-alpha cDNA was stably transfected in NIH3T3 cells, there was no increase in PLC activity. PLC-alpha is supposed to be a member not of PLC superfamily but of Trp-Cys-Gly-His-Cys-Lys motif-containing proteins consisting of protein disulfide isomerase, P5, ERp72, and thioredoxin. PLC-alpha should be redesignated ERp57 (ER-resided p57).

3T3 Cells↗
PubMed1994

Evi-1 raises AP-1 activity and stimulates c-fos promoter transactivation with dependence on the second zinc finger domain.

Evi-1 is a gene, encoding a zinc finger protein, associated with a common viral integration site in murine leukemias. It is suggested that Evi-1 plays important roles in embryogenesis and transformation of myeloid cells. To elucidate mechanisms by which Evi-1 induces such biological effects, we analyzed the relationship between Evi-1 and AP-1 which could regulate cellular proliferation and differentiation. When Evi-1 was expressed, transactivation through a 12-O-tetradecanoylphorbol 13-acetate-responsive element was observed in NIH3T3 and P19 cells. Evi-1-transfected P19 cells showed some differentiated phenotypes and increased expression of endogenous c-Jun and c-Fos. These results indicate that Evi-1 raises AP-1 activity. Evi-1 caused stimulation of the c-fos promoter transactivation, which seems to be a main mechanism of AP-1 activation, through at least two portions of the promoter. Evi-1 has the first zinc finger domain at the N terminus and the second zinc finger domain near the C-terminus. We constructed deletion mutants of Evi-1 and investigated the functions of these domains. It was shown that the second zinc finger domain is essential for the activation of AP-1 and transactivation of the c-fos promoter.

3T3 Cells↗
PubMed1994

Replacement of both tryptophan residues at 388 and 412 completely abolished cytochalasin B photolabelling of the GLUT1 glucose transporter.

A mutated GLUT1 glucose transporter, a Trp-388, 412 mutant whose tryptophans 388 and 412 were both replaced by leucines, was constructed by site-directed mutagenesis and expressed in Chinese hamster ovary cells. Glucose transport activity was decreased to approx. 30% in the Trp-388, 412 mutant compared with that in the wild type, a similar decrease in transport activity had been observed previously in the Trp-388 mutant and the Trp-412 mutant which had leucine at 388 and 412 respectively. Cytochalasin B labelling of the Trp-388 mutant was only decreased rather than abolished, a result similar to that obtained previously for the Trp-412 mutant. Cytochalasin B labelling was finally abolished completely in the Trp-388, 412 mutant, while cytochalasin B binding to this mutant was decreased to approx. 30% of that of the wild-type GLUT1 at the concentration used for photolabelling. This level of binding is thought to be adequate to detect labelling, assuming that the labelling efficiency of these transporters is similar. These findings suggest that cytochalasin B binds to the transmembrane domain of the glucose transporter in the vicinity of helix 10-11, and is inserted covalently by photoactivation at either the 388 or the 412 site.

Animals↗