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K Nagamine

Publications and source records attributed to K Nagamine.

At least 19 recordsLinked to original sources
PubMed2003

Discovery of temperature-dependent phenomena of muon-catalyzed fusion in solid deuterium and tritium mixtures.

A systematic experimental study on muon-catalyzed fusion was conducted using a series of solid deuterium and tritium mixtures. A variety of conditions were investigated, i.e., tritium concentrations from 20% to 70%, and temperatures from 5 to 16 K. With decreasing temperature, we observed an unexpected decrease in the muon cycling rate (lambda(c)) and an increase in the muon loss probability (W). The origins of these observed changes were interpreted by the temperature-dependence in the dt mu formation process for lambda(c) and that in the muon reactivation process after muon-to-alpha sticking for W.

Journal Article↗
PubMed2002

Non-Fermi-liquid spin dynamics in CeCoGe3-xSi(x) for x = 1.2 and 1.5.

Muon spin relaxation has been measured in CeCoGe3-xSi(x) at the magnetic/nonmagnetic boundary compositions of x = 1.2 and x = 1.5. Both the alloys are found to exhibit an ordered region and a disordered region. At x = 1.2, short-range magnetic ordering is observed below 0.86 K in the ordered region. The disordered region is paramagnetic and the muon spin-lattice relaxation rate lambda2 in this region displays non-Fermi-liquid (NFL) spin dynamics, i.e., the power law lambda2 proportional to T0.72 which shows the formation of Griffiths phase. lambda2 in the x = 1.5 alloy displays logarithmic (NFL) scaling below 1 K, in agreement with the theory of a T = 0 K magnetic transition.

Journal Article↗
PubMed2002

Accelerated reaction by loop-mediated isothermal amplification using loop primers.

Loop-mediated isothermal amplification (LAMP) is a novel nucleic acid amplification method that amplifies DNA with high specificity, efficiency and rapidity under isothermal conditions using a set of four specially designed primers and a DNA polymerase with strand displacement activity. We have developed a method that accelerates the LAMP reaction by using additional primers, termed loop primers. Loop primers hybridize to the stem-loops, except for the loops that are hybridized by the inner primers, and prime strand displacement DNA synthesis. Although both inner and loop primers react via the loops, they do so by different mechanisms. The LAMP method presented here uses loop primers to achieve reaction times of less than half that of the original LAMP method. Since the total time of analysis including detection is less than 1h, this new method should facilitate genetic analysis, including genetic diagnosis in the clinical laboratory.

Base Sequence↗
PubMed2001

Detection of loop-mediated isothermal amplification reaction by turbidity derived from magnesium pyrophosphate formation.

The loop-mediated isothermal amplification (LAMP) is a novel nucleic acid amplification method that uses only one type of enzyme. One of the characteristics of the LAMP method is its ability to synthesize extremely large amount of DNA. Accordingly, a large amount of by-product, pyrophosphate ion, is produced, yielding white precipitate of magnesium pyrophosphate in the reaction mixture. Judging the presence or absence of this white precipitate allows easy distinction of whether nucleic acid was amplified by the LAMP method. Since an increase in the turbidity of the reaction mixture according to the production of precipitate correlates with the amount of DNA synthesized, real-time monitoring of the LAMP reaction was achieved by real-time measurement of turbidity.

Base Sequence↗
PubMed2001

Signaling pathways leading to transcription and translation cooperatively regulate the transient increase in expression of c-Fos protein.

The mechanisms by which growth factors trigger signal transduction pathways leading to the regulation of c-Fos expression are of great interest. In this study we investigated the effect of hepatocyte growth factor (HGF/SF) and epidermal growth factor (EGF) on the expression of c-fos and its product, c-Fos, in human epithelial cell line MKN74. The expression level of c-Fos protein in HGF/SF-stimulated cells was 5--10-fold higher than that in EGF-stimulated cells, whereas the level of c-fos mRNA induced by HGF/SF was similar to that by EGF. The hyperphosphorylation of eukaryotic initiation factor 4E-binding protein 1 (4E-BP1), indicative of an increased number of translation initiation complexes, was detected only in HGF/SF-induced MKN74 cells. Activation of phosphatidylinositol-3'-OH kinase and FKBP12-rapamycin associated mammalian target of rapamycin (FRAP/mTOR) was observed after the treatment with HGF/SF. Pretreatment with an inhibitor of either one, i.e. LY294002 for phosphatidylinositol-3'-OH kinase or rapamycin for FRAP/mTOR, completely inhibited 4E-BP1 phosphorylation and decreased the c-Fos synthesis induced by HGF/SF down to the level found in EGF-induced cells. These results suggest that the phosphorylation of 4E-BP1 is stimulated by HGF/SF in a manner requiring both phosphatidy-linositol-3'-OH kinase-dependent and FRAP/mTOR-dependent pathways, thereby stimulating c-fos mRNA translation. Regulation of the translation process of c-fos mRNA in addition to the immediate activation of c-fos transcription is necessary for the transient increase in the level of c-Fos protein to stimulate cell proliferation.

Cell Line↗
PubMed2000

The DNA sequence of human chromosome 21.

Chromosome 21 is the smallest human autosome. An extra copy of chromosome 21 causes Down syndrome, the most frequent genetic cause of significant mental retardation, which affects up to 1 in 700 live births. Several anonymous loci for monogenic disorders and predispositions for common complex disorders have also been mapped to this chromosome, and loss of heterozygosity has been observed in regions associated with solid tumours. Here we report the sequence and gene catalogue of the long arm of chromosome 21. We have sequenced 33,546,361 base pairs (bp) of DNA with very high accuracy, the largest contig being 25,491,867 bp. Only three small clone gaps and seven sequencing gaps remain, comprising about 100 kilobases. Thus, we achieved 99.7% coverage of 21q. We also sequenced 281,116 bp from the short arm. The structural features identified include duplications that are probably involved in chromosomal abnormalities and repeat structures in the telomeric and pericentromeric regions. Analysis of the chromosome revealed 127 known genes, 98 predicted genes and 59 pseudogenes.

Base Sequence↗
PubMed2000

Solitary brain metastasis from papillary thyroid carcinoma in a patient with depression: report of a case.

Papillary carcinoma of the thyroid is a common thyroid malignancy with a relatively good prognosis. However, distant metastases may develop and become threatening, particularly to older patients, in a more aggressive manner. We report herein the clinical, radiological, and pathological findings of a patient with papillary thyroid carcinoma who had a solitary cerebral metastasis. The patient had been suffering from depression and had already undergone a hemithyroidectomy for primary thyroid carcinoma, and was known to have metastatic thyroid carcinoma of the lungs and bone. After the removal of the remnant thyroid gland prior to radioiodine (131I) therapy, he developed additional problems related to depression. Electroencephalography played an important role in identifying suspected brain metastasis and computed tomography demonstrated a space-occupying lesion in the left cerebral hemisphere. Consequently, an early removal of intracranial mass could be performed without any further life-threatening complications. Moreover, after removal of the brain mass the patient's depression improved immediately without the use of any antidepressants. This case report indicates the possibility that a patient's depression might be associated with brain metastasis from papillary thyroid carcinoma, and also suggests that an early diagnosis with the appropriate surgical management of a brain metastasis followed by radioiodine therapy could be valuable for achieving a prolonged disease-free period.

Bone Neoplasms↗
PubMed1999

Autoimmune regulator is expressed in the cells regulating immune tolerance in thymus medulla.

The AIRE gene (autoimmune regulator), coding for a putative transcriptional regulatory factor, is mutated in autoimmune-polyendocrinopathy-candidiasis ectodermal dystrophy (APECED). We have investigated the expression of the AIRE gene by mRNA in situ hybridization and immunohistochemistry in various human tissues. Here we show that AIRE is expressed in distinct cells in thymus medulla, and also in rare cells in lymph node paracortex and medulla, and in spleen and fetal liver, but not in the target organs of autoimmune destruction. Double immunofluorescence studies revealed that in thymus medulla both epithelial (cytokeratin positive) and non-epithelial cells expressed AIRE. Subcellularly, AIRE was localised in nuclear dots in thymus and lymph node and also in transfected cells. The cellular localisation of AIRE and its nuclear localisation, compatible with its predicted protein domains, suggest that AIRE may regulate the mechanisms involved in the induction and maintenance of immune tolerance.

Biomarkers↗
PubMed1999

Mutation analyses of North American APS-1 patients.

Autoimmune polyendocrinopathy syndrome type 1 (APS-1; MIM# 240300) is a rare autosomal recessively inherited disease characterised by destructive autoimmune diseases of endocrine glands. The gene responsible for APS-1, known as AIRE (for autoimmune regulator), was recently identified and contains motifs suggestive of a transcription regulator. To date, nine APS-1-associated mutations have been identified in the AIRE gene, including two common mutations R257X and 1094-1106del. In addition to these two mutations, we report seven novel mutations in 16 APS-1 patients from North America. We found that 1094-1106del and R257X were the most common mutations in this population of mixed geoethnic origin, accounting for 17/32 and 4/32 alleles, respectively. Haplotype analyses suggest that both are recurrent mutations, occurring on several different haplotypes with closely linked markers. All the novel mutations appear to be rare, occurring in only single APS-1 families. After examining all coding sequences and exon/intron boundaries of the AIRE gene, the other APS-1 allele remained unidentified in three patients. Genotype-phenotype correlations for APS-1 remain difficult, suggesting that other genetic or environmental factors, or both, influence the clinical presentation and disease progression in individual APS-1 patients.

DNA Mutational Analysis↗
PubMed1998

Molecular cloning of a novel putative Ca2+ channel protein (TRPC7) highly expressed in brain.

We have isolated cDNA clones for a novel human protein, TRPC7 (transient receptor potential-related channels), which consists of 1503 amino acid residues from the fetal brain and caudate nucleus cDNA libraries. Northern blot analysis indicated that the TRPC7 gene is highly expressed as a 6.5-kb transcript in brain. The TRPC7 protein has significant homology with Caenorhabditis elegans hypothetical proteins T01H8.5, C05C12.3, and F54D1.5 and with Drosophila and human transient receptor potential (trp) proteins. The TRPC7 protein has seven putative transmembrane domains that probably constitute a Ca2+ channel as in the above-mentioned proteins. Genomic sequencing revealed that the TRPC7 gene consists of 32 exons spanning approximately 90 kb. The TRPC7 gene was mapped between D21S400 and D21S171 on human chromosome 21q22.3, 14 kb distal to a NotI site in D21S400. This novel TRPC7 gene could be a candidate gene for genetic disorders such as bipolar affective disorder, nonsyndromic hereditary deafness, Knobloch syndrome, and holoprosencephaly, which were mapped to this region.

Amino Acid Sequence↗
PubMed1998

A common mutation in Sardinian autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy patients.

Autoimmune polyendocrinopathy-candidiasisectodermal dystrophy (APECED; also called APS-1,) is a rare autosomal recessive disorder that is more frequent in certain isolated populations. It is characterized by two of the three major clinical symptoms that may be present: Addison's disease, and/or hypoparathyroidism and/or chronic mucocutaneous candidiasis. We have recently identified the gene for APECED, which we termed AIRE (for autoimmune regulator). AIRE is expressed in thymus, lymph nodes and fetal liver, and encodes a protein with two putative zinc fingers and other motifs suggestive of a transcriptional regulator. Seven mutations have been described to date, including R257X, the predominant Finnish and northern Italian APECED allele, which has also been observed in other patients of diverse origin on different haplotypes. A 13-bp deletion (1094-1106del) has also been observed in several patients of different geo-ethnic origin. The other described mutations appear to be rare. We present mutational analyses of the AIRE gene in ten Sardinian APECED families and show that there is a mutation, R139X, associated with one predominant haplotype unique to the Sardinian patients (18/20 independent alleles). The carrier frequency of R139X in Sardinia is 1.7%, giving an estimated population frequency of APECED of 1/14,400. Using linkage disequilibrium data, the estimated age of the R139X mutation is between 20 and 25 generations. A previously described 13-bp deletion was also observed on an allele of one patient. The identification of a single common Sardinian APECED mutation will facilitate its genetic diagnosis. Given the carrier frequency of R139X in the Sardinian population, AIRE may be implicated in the pathogenesis of other autoimmune diseases in the Sardinian population, particularly those affecting the endocrine system.

DNA Mutational Analysis↗
PubMed1998

Common mutations in autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy patients of different origins.

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED; OMIM *240300, also called APS 1,) is a rare autosomal recessive disorder that is more frequent in certain isolated populations. It is generally characterized by two of the three major clinical symptoms that may be present, Addison's disease and/or hypoparathyroidism and/or chronic mucocutaneous candidiasis. Patients may also have a number of other clinical symptoms including chronic gastritis, gonadal failure, and rarely, autoimmune thyroid disease and insulin-dependent diabetes mellitus. We and others have recently identified the gene for APECED, which we termed AIRE (for autoimmune regulator). AIRE is expressed in thymus, lymph nodes, and fetal liver and encodes a protein containing motifs suggestive of a transcriptional regulator, including two zinc finger motifs (PHD finger), a proline-rich region, and three LXXLL motifs. Six mutations, in cluding R257X, the predominant Finnish APECED allele, have been defined. R257X was also observed in non-Finnish APECED patients occurring on different chromosomal haplotypes suggesting different mutational origins. Here we present mutation analyses in an extended series of patients, mainly of Northern Italian origin. We have detected 12 polymorphisms, including one amino acid substitution, and two additional mutations, R203X and X546C, in addition to the previously described mutations, R257X, 1096-1097insCCTG, and a 13-bp deletion (1094-1106del). R257X was also the common mutation in the Northern Italian patients (10 of 18 alleles), and 1094-1106del accounted for 5 of 18 Northern Italian alleles. Both R257X and 1094-1106del were both observed in patients of four different geo-ethnic origins, and both were associated with multiple different haplotypes using closely flanking polymorphic markers showing likely multiple mutation events (six and four, respectively). The identification of common AIRE mutations in different APECED patient groups will facilitate its genetic diagnosis. In addition, the polymorphisms presented provide the tools for investigation of the involvement of AIRE in other autoimmune diseases, particularly those affecting the endocrine system.

Female↗
PubMed1997

Cloning of the cDNA for a new member of the immunoglobulin superfamily (ISLR) containing leucine-rich repeat (LRR).

We isolated cDNAs for a novel protein with a calculated molecular mass of 46 kDa, containing a leucine-rich repeat (LRR) with conserved flanking sequences and a C2-type immunoglobulin (Ig)-like domain. This novel protein was considered to be a new member of the Ig superfamily and was named ISLR (immunoglobulin superfamily containing LRR). These domains are known to be important for protein-protein interaction or cell adhesion, and therefore it is possible that the novel protein ISLR may also interact with other proteins or cells. Northern blot analysis showed the presence of a 2.4-kb transcript in various human tissues including retina, heart, skeletal muscle, prostate, ovary, small intestine, thyroid, adrenal cortex, testis, stomach, and spinal cord as well as fetal lung and fetal kidney. The ISLR gene was mapped on human chromosome 15q23-q24 by fluorescence in situ hybridization.

Amino Acid Sequence↗
PubMed1997

Genomic organization and complete nucleotide sequence of the human PWP2 gene on chromosome 21.

The human PWP2 gene is the human homologue of the yeast periodic tryptophan protein 2 (PWP2) gene and is a member of the gene family that contains tryptophan-aspartate (WD) repeats. Genomic sequencing revealed that the human PWP2 gene consists of 21 exons spanning approximately 24 kb and locates just between the two genes EHOC-1 and KNP-I and distal to a NotI site of LJ104 (D21S1460) on chromosome 21q22.3. Analysis of the 5'-flanking DNA sequence revealed that the upstream region of the PWP2 gene is associated with a CpG island containing the NotI site of LJ104. Since PWP2 is considered to be a candidate for genetic disorders mapped in the 21q22.3 region, the information including nucleotide sequence and genomic organization of the PWP2 gene should be invaluable for the mutation analysis of the corresponding genetic disorders.

Base Sequence↗
PubMed1997

Genomic organization and complete nucleotide sequence of the TMEM1 gene on human chromosome 21q22.3.

TMEM1 (EHOC-1) gene encodes a putative transmembrane protein and is located on human chromosome band 21q22.3. Analysis of a 122,638-bp genomic sequence revealed that TMEM1 gene consists of 23 exons spanning approximately 94 kb and is transcribed in the direction of centromere to telomere. The 5' region of the TMEM1 gene was associated with a CpG island and the 3' end of the TMEM1 gene was mapped just proximal to the 5' end of the neighboring gene PWP2. We determined that the TMEM1 gene encodes a protein of 1,259 amino acids, which is 69-amino acids longer than the previously reported sequence. Since TMEM1 gene is considered to be a candidate for genetic disorders mapped in the 21q22.3 region, the information including complete nucleotide sequence and genomic organization of the TMEM1 gene should be invaluable for the mutation analysis of the corresponding genetic disorders.

Amino Acid Sequence↗