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Biomedical subjects

K Itakura

Publications and source records attributed to K Itakura.

At least 163 records · Page 9Linked to original sources
PubMed1979

A new HLA-B antigen (HOK-1) found in the Japanese.

The HLA-B8 antigen is one of the characteristic antigens associated with organ specific autoimmune diseases among Caucasians. Among the Japanese, HLA-B8 positives have been assumed to be extremely rare. By using some HLA-B8 typing sera, a new HLA-B antigen, HLA-Bw4 positive, was found in the Japanese. This new HLA-B antigen, tentatively called HOK-1, showed a phenotype frequency of 3.7% and a gene frequency of 1.9 +/- 0.6%. This antigen has a strong linkage disequilibrium with HLA-Cw1 among the Japanese.

Chromosome Mapping↗
PubMed1978

Chemical synthesis of genes for human insulin.

A rapid chemical procedure has been developed and used for the synthesis of 29 oligodeoxyribonucleotides to build synthetic genes for human insulin. The gene for insulin B chain, 104 base pairs, and the one for A chain, 77 base pairs, were designed from the amino acid sequence of human polypeptides. They bear single-stranded cohesive termini for the EcoRI and BamHI restriction endonucleases and are designed to be inserted separately into a pBR322 plasmid. The synthetic fragments, deca- to pentadecanucleotides, were synthesized by a block phosphotriester method with trinucleotides as building blocks. Final purification was by high-performance liquid chromatography. All 29 oligonucleotides were pure and had the correct sequences.

DNA↗
PubMed1978

Efficient correction of a mutation by use of chemically synthesized DNA.

The mutated base in the am3 lysis-defective mutant of the bacteriophage phiX174 has been corrected by a combined in vitro enzymatic DNA synthesis and in vivo replication of the heteroduplex product. Chemically synthesized oligodeoxyribonucleotides carrying the wild-type sequence have been used to prime DNA synthesis with am3 phiX174 DNA serving as a template. The resultant semisynthetic heteroduplex composed of an am3(+) strand and a wild-type (-) strand, with one mismatched base pair at position 587 on the phiX174 DNA sequence, was used to infect spheroplasts. The progeny phage were analyzed by a parallel plaque assay on wild-type host, Escherichia coli C, to screen for wild-type phenotype, and on E. coli HF4714, an amber suppressor strain, to determine the total progeny phage. When a 23-base-long synthetic primer was used, about one-third of total progeny were found to be wild type. Shorter primers yielded lower percentages of wild type; they also had poorer priming activity.

Base Sequence↗
PubMed1978

[Neutralization of static electricity charged on running vinyl chloride sheet by the use of soft beta-ray sources (author's transl)].

The feasibility of 147Pm and 3H beta-ray sources as static eliminator was experimentally investigated. A sheet of vinyl chloride of 0.1 mm in thickness was used as an example of electrified materials. Its surface charge densities before and after beta-ray neutralization were measured as the function of electrostatic charge changing the speed of the sheet and the distance between the beta-ray source and the sheet. With a 147Pm beta-ray source of 200mCi in effective activity, almost complete neutralization was found for the sheet with the charge density less than 6 X 10(-6) C/m2 running at the speed of 0.18 m/s. In the case of the running speed of 0.5 m/s frequently used in industry, the electrostatic charge below 3 X 10(6) C/m2, where corona discharger is not so effective, was also perfectly eliminated. It was found that the optimal distance between the beta-ray source and the sheet was 10 cm in the case of 147Pm. The use of 3H beta-ray source of 1 Ci was not satisfactory. These results demonstrate that 147 Pm beta-ray source operates most efficiently as static eliminator when the charge density of material and/or its moving speed is not high.

Chemical Phenomena↗
PubMed1977

Expression in Escherichia coli of a chemically synthesized gene for the hormone somatostatin.

A gene for somatostatin, a mammalian peptide (14 amino acid residues) hormone, was synthesized by chemical methods. This gene was fused to the Escherichia coli beta-galactosidase gene on the plasmid pBR322. Transformation of E. coli with the chimeric plasmid DNA led to the synthesis of a polypeptide including the sequence of amino acids corresponding to somatostatin. In vitro, active somatostatin was specifically cleaved from the large chimeric protein by treatment with cyanogen bromide. This represents the first synthesis of a functional polypeptide product from a gene of chemically synthesized origin.

Base Sequence↗
PubMed1977

Chemical synthesis of restriction enzyme recognition sites useful for cloning.

By a triester chemical synthesis method, three decameric DNA's have been made; these act as substrates for several restriction endonucleases, including Eco RI, Bam I, and Hind III. These homogenous decamers form duplexes that can be efficiently blunt-end ligated to themselves or to other DNA molecules by the action of T4 DNA ligase and thus are useful tools for molecular cloning experiments.

Base Sequence↗
PubMed1977

An HLA-D specificity found in the Japanese population.

A new HLA-D specificity was found in the Japanese population in two different laboratories. Japanese cell YT, found at Stanford, California, was A9,BW22J,CW1 and cell Wa, found at Sapporo, Japan, was A9,BW22J homozygous. They were shown to be HLA-D identical to the homozygous Japanese cell AH which submitted to the VIth International Histocompatibility Testing Workshop (Workshop number 2-001). This specificity was common in the Japanese (gf = 0.089) but completely absent from 62 Caucasians tested. Strong association of this specificity with HLA-BW22J was demonstrated.

California↗
PubMed1977

Reactivity of HLA typing sera against cultured lymphoblastoid cell lines and purified peripheral B and T cells from the same original donors.

Anomalous cytotoxicity reactions are observed in some HLA typing sera when cultured lymphoid cells are used as targets. These extra reactions are also detected when the purified B cells from the original donors of the cell lines are used. This observation strongly indicates that these extra reactions are directed to the B cell alloantigens which are normally expressed on B cells of the original donor.

B-Lymphocytes↗