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Biomedical subjects

A Kikuchi

Publications and source records attributed to A Kikuchi.

At least 451 records · Page 25Linked to original sources
PubMed1978

Immunological responsiveness and adjunct immunotherapy in lung cancer.

Immunocompetency was assessed before and after the operation in 40 patients with lung cancer by skin reaction against tuberculin (PPD) and dinitrochlorobenzene (DNCB), lymphocyte response to PHA, proportion of T-cells, macrophage migration inhibition test (MIT) and the presence of blocking factor. MIT was positive in 27 per cent and blocking factor was positive in 42 per cent. Immune response paralleled the clinical stage of the lesion. In curative resection cases, the immune response rose postoperatively, but declined in non-resectable or recurrent cases. The influence of postoperative radiation therapy, cancer chemotherapy and host mediated agents on the patients was observed. The feasibility of adjuvant specific immunotherapy is discussed.

Aged↗
PubMed1978

In vitro synthesis of ornithine transcarbamylase.

An in vitro system for the synthesis of ornithine transcarbamylase (OTCase) was established using iS-30 extract from E. coli MDS6-2(lambda) and DNA of a lambda transducing phage carrying argI and argF genes. This in vitro synthesis was completely dependent on the additon of DNA, and was sensitive to chloramphenicol and rifampicin. Radioisotopic analysis confirmed that the synthesized enzyme catalyzes the carbamylation of ornithine to citrulline. In the in vitro system the repression and derepression of OTCase synthesis could be observed by mixing iS-30 extracts prepared from argR+ and argR- cells. A remarkable maturation effect could be observed for the FFF enzyme, but not for the III enzyme. This system is considered to reflect the in vivo situation, and should therefore be useful for investigations on the regulation of OTCase synthesis in vivo.

Chloramphenicol↗
PubMed1978

Some regulation profiles of ornithine transcarbamylase synthesis in vitro.

The regulation profiles of OTCase (argF, argI) synthesis in vitro were investigated by using the in vitro system described in the accompanying paper. Addition of 2.6 mM arginine, crude repressor and partially purified repressor to the in vitro system demonstrated that lambdadargF-DNA-directed OTCase-FFF synthesis is more sensitive to the repressor than lambdapargI-DNA-directed OTCase-III synthesis. The effects of some low-molecular substances on FFF and III syntheses were investigated; guanosine 3'-diphosphate 5'-diphosphate (ppGpp) stimulated both syntheses while cAMP and guanosine 5'-tetraphosphate (Gpppp) were not effective on III synthesis and were slightly inhibitory for FFF synthesis. The substances had no effect on the maturation of the enzyme or on the activity of the enzyme, FFF or III, synthesized. We suggest that argF- and argI-genes are regulated in a slightly different fashion and that the operator-promotor regions are not completely identical for these two genes.

Cyclic AMP↗
PubMed1976

Studies on silk fibroin of Bombyx mori. I. Fractionation of fibroin prepared from the posterior silk gland.

1. Fractionation of fibroin prepared from the posterior silk glands of Bombyx mori was carried out. After carboxymethylation of the fibroin, it was fractionated by ammonium sulfate precipitation, Sephadex G-200 gel filtration and DEAE-cellulose column chromatography. 2. The fibroin was composed of at least two protein groups of large molecular size and three or four components of small molecular size, and, in addition, a mixture of proteins ranging in size from about 25,000 to more than 100,000 daltons with almost the same amino acid compositions. 3. The latter proteins contained about 48% glycine, 32% alanine, 11% serine, 4.5% tyrosine, 2% valine, and other minor amino acids. The sum of these main five amino acids accounts for more than 97% of the total amino acid residues of the proteins. 4. The present results indicate major heterogeneity in the molecular size of posterior silk gland fibroin, and, in addition, suggest the possibility of repeating sequences with relatively simple amino acid compositions in major peptide chains of fibroin.

Amino Acids↗
PubMed1975

Fractionation of whole histone by partition chromatography on Sephadex G-25.

Whole histone from calf thymus was fractionated by partition chromatography on the basis of distribution between an aqueous phase immobilized on Sephadex G-25 beads and mobile organic phases containing various concentrations of trichloroacetic acid. The chromatography was carried out by stepwise elution with five upper phases from water and butanol-2 solvent systems containing 4 M urea and 0.1-1.5% trichloroacetic acid, and finally water. Of the six peaks obtained, two (peaks 1 and 2) contained arginine-rich histones. Although these peaks were still heterogeneous electrophoretically, the band corresponding to F2al was observed only in the electrophoretic pattern of peak 1 and the main fraction in peak 2 was F3. A histone fraction having nearly equimolar amounts of arginine and lysine was obtained from peak 3. Its amino acid composition was similar to that of F2a2. Slightly lysine-rich histone obtained from peak 4 showed an amino acid composition typical of F2b. Peak 5 contained a histone fraction with a ratio of lysine/arginine of 6.14, showing a single band on gel-electrophoresis. Very lysine-rich histone (F1) was obtained from peak 6, and the electrophoretic pattern of this fraction showed a single band.

Amino Acids↗
PubMed1975

Fractionation, isolation and characterization of nonhistone chromosomal protein from calf thymus.

1) A method is described for the separation and fractionation of nonhistone chromosomal proteins from salt-urea dissociated calf thymus chromatin. After precipitating DNA in the dissociated chromatin solution with LaCl3, the chromosomal proteins in the supernatant were fractionated by SP-Sephadex C-25 column chromatography using a combination of NaCl stepwise and linear gradient elutions. Much care was taken to prevent proteolytic degradation of the chromosomal proteins during the preparation. 2) Among the protein fractions separated by this chromatography, twenty subfractions were found to be homogeneous on SDS-polyacrylamide gel electrophoresis. These purified proteins account for about 18% of the whole chromosomal protein. Eleven subfractions of these purified nonhistone proteins had ratios of acidic to basic amino acids above 1.0 and the nine remaining subfractions had ratios below 1.0, corresponding to nonhistone proteins of basic character. 3) The molecular weights of the purified nonhistone proteins ranged from 7,400 to 19,000.

Amino Acids↗
PubMed1975

Isolation and characterization of lambda transducing bacteriophages for argF, argI and adjacent genes.

Two genes for ornithinetranscarbamylase exist in strain Escherichia coli K-12, argI, at 85 min, and argF, at 7 min. In an attempt to compare the deoxyribonucleic acid material of these two genes, the lambda transducing phages carrying a portion of the argI region, lambda dvalS argI, lambda pvalS, and lambda dvalS pyrB, and of the argF region, lambda dargF, have been isolated. Their structure, including that of phi 80dargF previously isolated, was studied by the method of heteroduplex mapping. In this paper, the results of this mapping are reported.

Centrifugation, Density Gradient↗