Search PubMed⌕ Search

Biomedical subjects

T Nishida

Publications and source records attributed to T Nishida.

At least 721 records · Page 40Linked to original sources
PubMed1979

[Studies on the cytotoxic action of new restorative resins (in vitro) (author's transl)].

Biocompatibility of restorative resins, i.e., Isopast, Clearfil bond system F, Compodent II and Adaptic, was investigated by using cell nuclei counting and agar diffusion method of L cells. The results obtained were as follows: 1) Isopast showed moderate cytotoxicity immediately after mixing, followed by marked decrease of cytotoxicity during setting process. Cytotoxicity as a whole was the least as compared to the other tested. 2) Clearfil restorative resin showed severe cytotoxicity immediately after mixing. Decrease of cytotoxicity similar to Compodent II was found. However, it was found that set material had mild cytotoxicity even after three exchanges of the extract. 3) Bonding agent and catalyst of Clearfil bond system F showed severe cytotoxicity. 4) Change of cytotoxicity of Compodent II and Adaptic was reconfirmed.

Cell Division↗
PubMed1979

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of bovine serum albumin oligomers produced by lipid peroxidation.

The oligomers of bovine serum albumin were produced by controlled reaction with peroxidizing linoleic acid to examine their possible utility as calibration proteins insodium dodecyl sulfate-polyacrylamide gel electrophoresis. The polymerization was effected in reaction mixtures containing linoleic acid undergoing peroxidation in the presence of ascorbic acid, and conditions that yield soluble oligomers with a wide molecular weight distribution were established. The interaction of these soluble oligomers with sodium dodecyl sulfate exhibited a binding isotherm indistinguishable from that obtained with bovine serum albumin. Furthermore, sodium dodecy sulfate-polyacrylamide gel electrophoresis of the albumin oligomers conformed to the empirical relation of molecular weight to mobility that pertains to the use of these oligomers as standard molecular weight markers.

Electrophoresis, Polyacrylamide Gel↗
PubMed1978

Syntheses of C-peptides and human proinsulin.

Syntheses of human, dog, rat, and duck C-peptides and their analogues and preliminary results on the total synthesis of human proinsulin are described. In the syntheses of the C-peptides, chain elongation was performed exclusively by the azide-fragment condensation method in solution. The synthetic human, dog, rat, and duck C-peptides and their analogues were proved to be homogeneous by several analytic means. With these synthetic peptides, radioimmunoassay systems for dog, rat, and duck C-peptides were developed. For the total synthesis of human proinsulin, 10 protected peptide hydrazides were prepared, and the linearly protected hexaoctacontapeptide having the proposed sequence of human proinsulin was constructed by the azide-fragment condensation method in solution starting from the C-terminal undecapeptide (HP 75-86). After deblocking of the alpha-amino protection, the partially protected hexaoctacontapeptide was treated with sodium in liquid ammonia. The ensuing sulfhydryl form was converted to the S-sulfonate form, which was reduced and then air-oxidized. The oxidized material was purified by gel filtration on Sephadex G-50 (fine) followed by ion-exchange chromatography on DEAE-cellulose. The cross-reactivity in the insulin radioimmunoassay of the ensuing product was 62.5 per cent of porcine proinsulin on a weight basis at B/Bo = 60 per cent. Acid hydrolysis and amino acid analysis of this product gave the theoretically expected ratios. In addition, this peptide, as well as the S-sulfonate form of the hexaoctacontapeptide, showed displacement curves superimposable on that of synthetic human C-peptide on an equimolar basis in the human C-peptide radioimmunoassay (antiserum 527). These results confirm the synthesis of human proinsulin.

Amino Acid Sequence↗
PubMed1978

Parallel between circadian rhythms of intestinal disaccharidases and foot intake of rats under constant lighting conditions.

The relationship between the circadian rhythmic changes in the disaccharidase activities of the small intestine and the circadian feeding pattern was investigated in rats kept in the dark or in the light continuously for 4 weeks. Rats kept continuously in the light and fed ad libitum showed no rhythmic change in food intake or disaccharidase activities, but when they were only fed during a restricted time of day, their disaccharidase activities showed rhythmic changes with higher activities around the feeding time. In contrast, rats kept continuously in the dark and fed ad libitum showed circadian variations in food intake and disaccharidase activities essentially similar to rats kept under the normal light-dark lighting schedule. These findings show that the rhythm of disaccharidase activities is synchronized with the feeding rhythm, not with the lighting rhythm.

Animals↗
PubMed1978

[Gene constitution of miniature "shiba" goats (author's transl)].

Genetic surveys were carried out on the miniature "Shiba" goats which have been raised in Nagasaki Prefecture, Japan. Recently, in thhe prefecture the number of "Shiba" goats have been markedly decreased to totally about 190 which are kept now only in two towns. Morphological genetic traits were observed to have been coming homogenous in Nagasaki Prefecture, and homogeneity of the traits in the colonies kept the National Institute of Animal Industry and in Stock Farm of University of Tokyo, especially in the latter, was remarkably high. The "Shiba" goats have white coat color, horns and supernumerary teats, but not wattles. Electrophoretic examinations of genetic variations at 27 blood protein loci revealed that variability in the "Shiba" goat populations were lower than that of the Japanese Saanen breed, and that the amount of gene flow from the Saanen breed into the "Shiba" goats was estimated to be smaller than into the present-day Okinawa meat goats. The genetic variability of the colony in Stock Farm of University of Tokyo was observed to be conspicuously low. From the results of pedigree analysis such a decay of genetic variability was postulated to come about from unavoidable inbreeding resulted from smallness both in numbers of foundation animals and in effective population size of the colony.

Animals↗
PubMed1977

Nature of interaction of dextran sulfate with lecithin dispersions and lysolecithin micelles.

Lecithin and lecithin/cholesterol dispersions as well as lysolecithin micelles were used to provide basic information on the mechanism of the interaction of zwitterionic phospholipids with dextran sulfate. The addition of dextran sulfate to lecithin dispersions or lysolecithin micelles in the presence of Ca2+ produced insoluble complexes. At each Ca2+ concentration, the amount of insoluble complex formed was maximal at the equivalence dextran sulfate/phospholipid weight ratio. An increase in CaCl2 concentration up to 10 mM progressively increased the equivalence ratios for the phospholipids. Further increase in Ca2+ concentration did not influence the equivalence ratio for maximal complex formation. The conversion of lecithin dispersions into insoluble complexes was very effective even at low Ca2+ concentrations. Approximately 70% of the lecithin was converted to the insoluble complex at CaCl2 concentrations as low as 0.5 mM and the complete conversion was observed at CaCl2 concentrations above 2.5 mM. In the presence of cholesterol, the precipitation curve for insoluble complex formation became broader than that of lecithin alone, indicating the enhancing effect of cholesterol on the insoluble complex formation both below and above the equivalence ratio. The stoichiometry of the interaction of the zwitterionic phospholipids with dextran sulfate inthe presence of calcium was determined using lysolecithin micelles. At the CaCl2 concentrations above 20 mM, the insoluble complex possessed a ratio of lysolecithin/calcium/sulfate group of approximately 2/1/3 (mol/mol/mol). It appears that the formation of the insoluble complex of lecithin or lysolecithin with dextran sulfate represents the mutually enhancing interactions involving both positive and negative charges of the zwitterionic phospholipids. These are the direct electro static interaction between the phospholipid choline nitrogen and the sulfate groups of dextran sulfate and the calcium cross-linking of the phosphate groups to the sulfate groups or to the phosphate groups of neighboring phospholipids.

Binding Sites↗
PubMed1977

A specific method for the determination of threonine in rat blood plasma using aldehyde dehydrogenase.

A simple and sensitive method for the determination of threonine in rat blood plasma using aldehyde dehydrogenase after oxidation with periodate was developed. By the present method, threonine could be completely discriminated from serine and determined at the nanomole level. The amount of threonine in rat blood plasma obtained by the present method coincided well with the value determined on an amino acid analyzer.

Aldehyde Oxidoreductases↗