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Biomedical subjects

J Takeda

Publications and source records attributed to J Takeda.

At least 145 records · Page 8Linked to original sources
PubMed1998

[Mutations in the genes of the HNF-family cause maturity-onset diabetes of the young (MODY)].

Maturity-onset diabetes of the young (MODY) is a monogenic form of non-insulin-dependent diabetes mellitus (NIDDM) characterized by an early age of onset, often in childhood or adolescence and usually < 25 years of age, and autosomal dominant inheritance. Clinical characterization of patients with MODY indicates that impaired insulin secretion is the primary defect responsible for the hyperglycemia in these patients. Genetic studies have thus far identified five MODY susceptibility genes, four of which encode transcription factors; HNF (hepatocyte nuclear factor)-1 alpha, HNF-1 beta, HNF-4 alpha, and IPF1. The association of mutations in the genes for these transcription factors with early-onset familial diabetes indicates the importance of the HNF-regulatory network in determining pancreatic beta-cell function.

Adolescent↗
PubMed1998

[Clinical evaluation as palliative therapy of combination chemotherapy with continuous infusional 5-fluorouracil and consecutive low-dose cisplatin in unresectable gastrointestinal carcinoma].

Combination chemotherapy with continuous infusion 5-FU, 350 mg/m2/day and low-dose CDDP between 5 to 10 mg/body/day (day 1-5) was evaluated in 46 patients with unresectable gastric (34), colorectal (10) and biliary tract (2) carcinoma. This regimen was repeated for 4 weeks. The overall response rate was 45.7% (21/46), but the resectable rate was only 10.9% (5/46). Toxic response (> grade 2) was 22% (10/46). After chemotherapy, the patients preserved good performance status and quality of life. Median survival time was about 11 months, and there was no significant difference between CR or PR cases and NC one. Survival time of patients correlated not to the reduction rate of tumor but to conditions of hosts (e.g., performance status, quality of life). These results suggested that this therapy is an effective palliative chemotherapy for patients with unresectable gastrointestinal carcinoma.

Adult↗
PubMed1997

Structures and chromosomal localizations of the glycosylphosphatidylinositol synthesis gene PIGC and its pseudogene PIGCP1.

More than 10 genes are involved in the biosynthesis of glycosylphosphatidylinositol (GPI), which anchors many mammalian cell surface proteins to the membrane. Paroxysmal nocturnal hemoglobinuria (PNH) is caused by a somatic mutation in a GPI biosynthesis gene within the hematopoietic stem cell. The X-linked gene PIGA has been found to be mutated in all patients with PNH. This is probably because all other GPI synthesis genes are autosomal; hence two somatic mutations must occur to cause PNH, whereas one somatic mutation is sufficient to inactivate PIGA. Consistent with this notion, three other genes, PIGB, PIGF, and PIGH, are autosomal. Here we isolated a genomic clone of another GPI-synthesis gene, PIGC, and mapped it to chromosome 1q23-q25, further supporting this notion. PIGC is an intronless gene. We found an intronless pseudogene of PIGC, PIGCP1, and mapped it to chromosome 11p12-p13. The presence of a processed pseudogene is a common feature of PIGA, PIGF, and PIGC.

Amino Acid Sequence↗
PubMed1997

Tissue-specific knockout of the mouse Pig-a gene reveals important roles for GPI-anchored proteins in skin development.

Glycosylphosphatidylinositol (GPI)-anchored proteins are widely distributed on plasma membranes of eukaryotes. More than 50 GPI-anchored proteins have been shown to be spatiotemporally expressed in mice with a deficiency of GPI-anchor biosynthesis that causes embryonic lethality. Here, we examine the functional roles of GPI-anchored proteins in mouse skin using the Cre-loxP recombination system. We disrupted the Pig-a gene, an X-linked gene essential for GPI-anchor biosynthesis, in skin. The Cre-mediated Pig-a disruption occurred in skin at almost 100% efficiency in male mice bearing two identically orientated loxP sites within the Pig-a gene. Expression of GPI-anchored proteins was completely absent in the skin of these mice. The skin of such mutants looked wrinkled and more scaly than that of wild-type mice. Furthermore, histological examination of mutant mice showed that the epidermal horny layer was tightly packed and thickened. Electron microscopy showed that the intercellular space was narrow and there were many small vesicles embedded in the intercellular space that were not observed in equivalent wild-type mouse skin preparations. Mutant mice died within a few days after birth, suggesting that Pig-a function is essential for proper skin differentiation and maintenance.

Animals↗
PubMed1997

Expression cloning of PIG-L, a candidate N-acetylglucosaminyl-phosphatidylinositol deacetylase.

Many eukaryotic cell surface proteins are bound to the cell membrane by a glycosylphosphatidylinositol (GPI) anchor. Several genes involved in GPI anchor biosynthesis have been cloned using complementation of mutant mammalian cell lines and yeasts that are defective in its biosynthesis pathway. However, the gene involved in the second step of this pathway, in which N-acetylglucosaminyl-phosphatidylinositol (GlcNAc-PI) is N-deacetylated to form glucosaminyl (GlcN)-PI, has not been cloned. In this study, we established a GPI anchor-deficient mutant of Chinese hamster ovary (CHO) cells defective in the second step. Complementation analysis with the known GPI anchor mutant cells demonstrated that it belonged to the same complementation group as the CHO cell mutant G9PLAP.85. Using the new mutant, we cloned a rat gene termed PIG-L (for phosphatidylinositol glycan class L) that is involved in this step. PIG-L encodes a 252-amino acid, endoplasmic reticulum membrane protein, most of which is in the cytoplasmic side. This orientation of PIG-L protein is consistent with the notion that the second step of GPI anchor biosynthesis occurs on the cytoplasmic side of the endoplasmic reticulum.

Amidohydrolases↗
PubMed1997

Cloning and characterization of exodus, a novel beta-chemokine.

Chemokines are a family of related proteins that regulate leukocyte infiltration into inflamed tissue. Some chemokines such as MIP-1 alpha also inhibit hematopoietic progenitor cell proliferation. Recently, three chemokines, MIP-1 alpha, MIP-1 beta, and RANTES, have been found to significantly decrease human immunodeficiency virus production from infected T cells. We report here the cloning and characterization of a novel human chemokine termed Exodus for its chemotactic properties. This novel chemokine is distantly related to other chemokines (28% homology with MIP-1 alpha) and shares several biological activities. Exodus is expressed preferentially in lymphocytes and monocytes, and its expression is markedly upregulated by mediators of inflammation such as tumor necrosis factor or lipopolysaccharide. Purified synthetic Exodus was found to inhibit proliferation of myeloid progenitors in colony formation assays. Exodus also stimulated chemotaxis of peripheral blood mononuclear cells. The sequence homology, expression, and biological activity indicate that Exodus represents a novel divergent beta-chemokine.

Amino Acid Sequence↗
PubMed1997

A patient with paroxysmal nocturnal hemoglobinuria bearing four independent PIG-A mutant clones.

Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by clonal blood cells that are deficient in the surface expression of glycosylphosphatidylinositol-anchored proteins due to somatic mutation in the X-linked gene PIG-A. In some patients, more than one abnormal clone may be present. Analysis of bulk DNA/RNA from granulocytes has been useful in identifying the predominant PIG-A mutation in each patient. However, it is often not useful in determining the presence of minor clones. Many patients have cells with partial deficiency. Here, we analyzed the PIG-A gene in two B-cell lines bearing complete or partial deficiencies, cells of hematopoietic progenitor colonies and peripheral blood granulocytes from the same patient. We found that two B-cell lines had different mutations, the granulocytes contained at least two mutants, and the hematopoietic progenitors contained four mutants. Three of the four were shared by B cells and/or granulocytes whereas the other one was found only in the hematopoietic progenitors. The partial deficiency was caused by a point mutation near an alternative splice site within exon 2 that resulted in partial decreases of activity and quantity of the full-length transcript. These results further show the oligoclonal nature of PNH and differences in extent of expansion among mutant clones.

Alternative Splicing↗
PubMed1997

Somatic variation during long-term subculturing of plant cells caused by insertion of a transposable element in a phenylalanine ammonia-lyase (PAL) gene.

We have identified a new En/Spm-like transposable element, Tdc1, in the 5' flanking region of a phenylalanine ammonia-lyase gene (gDcPAL1) that is normally induced by transferring cells of carrot suspension cultures to fresh liquid medium (transfer or dilution effect). The initial integration into gDcPAL1 occurred more than 4 years after culture initiation. Tdc1 was first detected in gDcPAL1 genomic clones of a genomic library made from cells of the same cultured cell line 7 years after its initiation and thus following repeated subculturing. Twelve years after initiation, about 5-10% of the cells had Tdc1 inserted into the gDcPAL1 gene, indicating that Tdc1 insertion into gDcPAL1 occurred in one (or more) cell(s) during the first 4-7 years of subculturing. These mutant cells did not disappear during numerous passages; instead the proportion of cells having this Tdc1 inserted into gDcPAL1 has been increasing over the last 5 years. The promoter activity and the inducibility by transfer/dilution of the gDcPAL1 gene harboring Tdc1 is reduced relative to wild type. Finally, we show that insertion of a transposable element is one of the mechanisms that can cause variation of plant cell cultures during repeated subculture.

Amino Acid Sequence↗
PubMed1997

HLA class-I-restricted and tumor-specific CTL in tumor-infiltrating lymphocytes of patients with gastric cancer.

Immune recognition of human cancers except melanoma is not well understood at either the cellular or the molecular level. We demonstrate in this study the existence of HLA class-I-restricted and tumor-specific CTL in IL-2-activated TIL (tumor-infiltrating lymphocytes) of all 4 gastric cancer patients tested. We established HLA A2-restricted and adenocarcinoma-specific CTL in 2 HLA A0201+ patients, and HLA A2402-restricted CTL recognizing both adenocarcinoma and squamous-cell carcinomas (SCC) in the 2 remaining HLA A2402+ patients. Further, HLA A3101-restricted and adenocarcinoma-specific CTL were established in 1 of the 2 HLA A2402+ patients who had HLA A3101 allele. HLA A2-, A2402- and A3101-restricted CD8+ CTL clones were established from these parental CTL lines. The 2 HLA A2-restricted CTL lines lysed 8 of 13 HLA A2+ adenocarcinoma cell lines established from different organs (stomach, colon, lung and breast) with different subtypes (HLA A0201, A0206 and A0207). The HLA A2-restricted CTL line recognized 9 and 6 different HPLC fractions of peptides eluted from the HLA A0201+ breast and HLA A0201+ colon adenocarcinoma cell lines, respectively. Allele-specific deletion of HLA A2 or A24 molecules was observed in some tumor lines that were not susceptible to lysis by the CTL lines. These results suggest that TIL of gastric cancer possess CTL recognizing different peptide antigens binding to different HLA-A alleles that are widely expressed on adenocarcinomas and also, to some extent, on SCC from different organs.

Adenocarcinoma↗
PubMed1997

A human urinary protease inhibitor (ulinastatin) inhibits neutrophil extracellular release of elastase during cardiopulmonary bypass.

OBJECTIVES: To determine the benefits of a human urinary protease inhibitor (ulinastatin) on postoperative pulmonary dysfunction associated with neutrophil activation during cardiopulmonary bypass. DESIGN: A prospective, randomized, clinical study. SETTING: The study was performed at Keio University Hospital, Tokyo. PARTICIPANTS: Eighteen adult patients scheduled for primary cardiac surgery. INTERVENTIONS: The patients were randomly assigned either to the control group (n = 8) or to the group (n = 10) receiving ulinastatin (600,000 U in total). MEASUREMENTS AND MAIN RESULTS: Human neutrophil ability to release elastase in response to N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP) in vitro was measured before and after cardiopulmonary bypass, together with plasma levels of neutrophil elastase complex, interleukin-B, and C3a. Intrapulmonary shunt fraction was then calculated. Neutrophil elastase release in response to fMLP significantly increased in the control group, but remained unchanged in the ulinastatin group. In addition, ulinastatin minimized the increase of plasma neutrophil elastase, independently of the production of interleukin-B or C3a. Simultaneously, ulinastatin ameliorated the increase of intrapulmonary shunt, which was correlated with extracellular elastase release. CONCLUSIONS: Ulinastatin attenuated the elevation of fMLP-induced elastase release, which was associated with the deterioration of gas exchange during cardiopulmonary bypass. The administration of this agent has a potential to lessen the risk of postperfusion lung injury.

Adult↗
PubMed1997

A novel protein that participates in nonself discrimination of malignant cells by homologous complement.

The human complement (C) system protects an individual against substances of nonself origin, including xenografts and microbial pathogens. Human cells express C-regulatory proteins, CD46 and CD55, thereby circumventing attack by C3, a major effector of C. Nevertheless, certain malignant cells, particularly those undergoing apoptotic stress, can activate homologous C, overcoming the regulatory actions of CD46 and/or CD55. The molecular mechanisms whereby malignant cells are tagged by homologous C3 remain largely unknown. We identified a novel gene product that converts human cells into targets for homologous complement. Only malignant cells and cell lines exposed to Fas or X-irradiation stimuli produced this protein, designated M161Ag, which was an unglycosylated 43-kDa protein. Analysis of cloned cDNAs indicated that this molecule was a secretory protein containing five amino acids encoded by TGA codons. Its functions were unique in that once secreted from the tumor cells, it bound back to the surface of these cells and activated homologous complement (C3) via the alternative pathway, allowing for C3 deposition on the membrane. This molecule may offer new insight into innate immunity; surveillance of tumor cells by complement is a common feature in the human immune system.

Amino Acid Sequence↗
PubMed1997

Effect of extradural analgesia on the paradoxical arousal response of the electroencephalogram.

Despite widespread recognition of the potential role of the processed electroencephalogram (pEEG) as a monitor of depth of anaesthesia, few studies have examined the effects of surgical stimuli on the intraoperative pEEG. Two groups of gynaecological patients (n = 10 in each group), with or without pre-incisional extradural analgesia, undergoing gynaecological laparotomy under nitrous oxide and isoflurane anaesthesia were monitored with routine haemodynamic observations and pEEG. Patients who received pre-incisional extradural analgesia showed no significant changes in pEEG variables during surgery (mean spectral edge frequency 95 percentile (SEF95) 13.3 (SD 1.4) Hz), whereas in all patients without pre-incisional extradural analgesia, a significant decrease in SEF95 was noted (6.5 (1.1) Hz after incision compared with a pre-incisional value of 12.5 (1.4) Hz) together with an increase in arterial pressure (paradoxical response). In the latter group, SEF95 and arterial pressure returned to pre-incisional values after extradural analgesia was established during operation. During emergence from anaesthesia, both groups showed a significant increase in SEF95 (25.7 (1.4) Hz). This study suggests that intraoperative pEEG arousal response was different from changes detected when anaesthesia was terminated at the end of surgery. Surgical stimuli in the absence of adequate analgesia induced a paradoxical arousal response.

Adult↗
PubMed1997

Molecular cloning of a pig homologue of membrane cofactor protein (CD46).

Organs of transgenic pigs that express human complement regulatory proteins are under assessment as an alternative to transplantation. A major barrier to the transplantation of pig organs is the hyperacute rejection caused by pre-existing antibodies and complement. Pig cells are very susceptible to human complement, presumably because pig cell-surface complement regulatory proteins are inefficient against it. Expression of human complement regulatory proteins, such as decay-accelerating factor and membrane cofactor proteins (MCP or CD46), by means of transgenes would confer resistance to human complement upon pig cells, thereby preventing hyperacute rejection. To express sufficient levels of human complement regulatory proteins at appropriate sites, regulatory elements of genes of pig membrane-bound complement regulatory proteins would be useful. To obtain their cDNAs, we transfected human cells with a pig cDNA library, selected cells by incubation with pig complement and rescued the plasmids. We cloned a cDNA for the pig homologue of MCP, pMCP. The cDNA encoded a predicted protein of 363 amino acids with 42% amino acid identity with human MCP. The pMCP consisted of four short consensus repeats, a Ser/Thr/Pro-rich domain, and transmembrane and cytoplasmic domains. Recombinant soluble pMCP that lacked transmembrane and cytoplasmic domains had factor I cofactor activity in C3b cleavage, indicating that it is functionally, as well as structurally homologous to MCP. FACS analysis with anti-pMCP mAb demonstrated that pMCP is expressed on all blood leukocytes, erythrocytes, and on endothelial and epithelial cell lines.

Amino Acid Sequence↗
PubMed1997

GPI-anchor synthesis in mammalian cells: genes, their products, and a deficiency.

Protein GPI anchors are ubiquitous in eukaryotic cells. More than 50 mammalian proteins are anchored to the membrane via GPI. GPI anchoring is a posttranslational modification occurring in the endoplasmic reticulum where preassembled GPI anchor precursors are transferred to proteins bearing a C-terminal GPI signal sequence. The GPI anchor precursors are synthesized in the endoplasmic reticulum by sequential addition of sugar and other components to phosphatidylinositol. More than ten genes participate in this biosynthetic pathway, eleven of the mammalian genes having been cloned by means of complementation of mutant cells that are defective in this pathway or based on sequence homology to previously cloned yeast counterparts. A somatic mutation in one of those genes, PIG-A, involved in the first reaction step, is responsible for the hemolytic disease, paroxysmal nocturnal hemoglobinuria.

Animals↗
PubMed1997

Leukocyte-endothelium interaction in the rat mesenteric microcirculation during halothane or sevoflurane anesthesia .

BACKGROUND: The effects of inhalational anesthetics on the microcirculation, including leukocyte dynamics, remain to be clarified. The authors investigated halothane and sevoflurane anesthesia to determine if these agents evoked leukocyte adhesion through endothelial cell-dependent mechanisms involving such adhesion molecules. METHODS: Rats were anesthetized with halothane or sevoflurane in 100% oxygen and the lungs were mechanically ventilated. Leukocyte behavior in mesenteric venules was recorded through intravital video microscopy under monitoring microvascular hemodynamics. To examine the mechanisms for leukocyte rolling and adhesion, these studies were repeated after animals were pretreated with a monoclonal antibody against P-selectin (MAb PB1.3) or against intracellular adhesion molecule-1 (ICAM-1; MAb 1A29): P-selectin required for rolling of circulating leukocytes and ICAM-1 for firm adhesive interactions with leukocyte integrins. RESULTS: Under baseline anesthetic conditions (1 minimum alveolar concentration [MAC]), venular wall shear rates, an index of the disperse force on marginating leukocytes, in the sevoflurane-treated rats were about two times higher than those with halothane. At 2 MAC, halothane caused a marked arteriolar constriction and decreasing shear rates concurrent with an increasing density of venular leukocyte adhesion. Sevoflurane at 2 MAC induced leukocyte rolling and adhesion, which were attenuated by PB1.3 and 1A29, without alterations in the wall shear rates. Halothane-induced leukocyte adhesion was not prevented by PB1.3 but it was by 1A29. CONCLUSIONS: Halothane or sevoflurane anesthesia induces venular leukocyte rolling and adhesion: P-selectin upregulation plays a crucial role in leukocyte rolling and adhesion during sevoflurane anesthesia, whereas low-flow perfusion is likely to evoke ICAM-1-dependent leukocyte adhesion during halothane anesthesia.

Anesthetics, Inhalation↗
PubMed1997

Action spectrum for induction of promoter activity of phenylalanine ammonia-lyase gene by UV in carrot suspension cells.

The full-length promoter (-2335) of the carrot (Daucus carota) phenylalanine ammonia-lyase gene (gDcPAL1) fused to the luciferase reporter gene was transiently transformed to carrot protoplasts by electroporation, and the promoter activity induced by monochromatic UV light of various wavelengths was examined. The action spectrum constructed from the fluence-response curves showed a single peak at around 280 nm, suggesting that the activation of the gDcPAL1 promoter is categorizable as one of the UVB light responses. The same assay system was applied to variously truncated gDcPAL1 promoters and to CaMV35S promoter fusion with various parts 5'-upstream of the gDcPAL1 promoter. The region from -396 to -190 (relative to the transcription start site) fused to the CaMV35S core (-90) promoter showed a 280 nm-dominant response. However, gDcPAL1 promoters truncated above -570 and -396, although they contain the region between -396 and -190, did not show such a typical UVB response, i.e. they responded to 260 nm light as much as to 280 nm light. The promoter truncated to below -190 also responded to 260 nm light as much as to 280 nm light. Therefore we assumed that the gDcPAL1 promoter is composed of three functionally different parts: the upstream above -570 (modulator), the region from -396 to -190 (UVB responsive) and the down-stream below -190 (UVB and C responsive). The overall UVB response of the gDcPAL1 full-length promoter is explained as the result of interaction of these three components.

Base Sequence↗
PubMed1997

Inhibitory effects of angiotensin-converting enzyme inhibitor on cefroxadine uptake by rabbit small intestinal brush border membrane vesicles.

Effects of angiotensin-converting enzyme (ACE) inhibitors, captopril, enalapril maleate and quinapril, on the uptake of aminocephalosporin antibiotic, cefroxadine, by rabbit small intestinal brush border membrane vesicles were examined. These ACE inhibitors significantly inhibited the uptake of cefroxadine, which is transported by H+/dipeptide transporter in the membrane, in the order of captopril < enalapril < quinapril in the presence of an inward H+ gradient. Inhibitory effect of quinapril was more marked than that of aminocephalosporin cephradine, while in the absence of an inward H+ gradient inhibition by these ACE inhibitors was much less. Dixon plot analysis showed that the inhibition by enalapril and quinapril in the presence of an inward H+ gradient occurred in a competitive manner and estimated inhibition constants of these two drugs to be 5.3 mM and 0.46 mM, respectively. These results suggested the strong affinity of these ACE inhibitors, especially quinapril, on the H+/dipeptide transporter.

Angiotensin-Converting Enzyme Inhibitors↗