Biomedical subjects
Publications and source records attributed to K Yagi.
To determine lipid peroxides in chloroform-methanol extracts of foods, a simple and sensitive colorimetric method using a new leucomethylene blue derivative was adopted. The amounts obtained by this method coincided well with those by the iodometric method and paralleled those by the thiobarbituric acid method.
Incorporation of chinoform-ferric chelate was demonstrable in cultured neural retinal cells of chick embryos after 1 h of incubation, and the lipid peroxide level in the cells was increased strikingly 1 h thereafter. On the other hand, free ferric ions were scarcely incorporated into the cells, and a significant increase in the lipid peroxide level in the cells was not observed. These data indicate that chinoform is carrier of iron for its passage through cell membranes and that the incorporated iron induces lipid peroxidation which in turn leads to neural cell degeneration.
Explore the source record for details and available documents.
The complete covalent structure of the 331 amino acids of mouse lactate dehydrogenase (LDH) A4 isozyme has been determined by sequence analyses of both the protein and the genomic DNA. The mouse LDH-A gene spans a length of at least 7000 bases from the translation initiation codon ATG to the end of the 3' untranslated region, and it contains six introns that interrupt the protein-coding sequence. The relationships between the exon-intron organization of LDH-A gene and the structural-functional domains of the protein are discussed.
A mouse lactate dehydrogenase-A cDNA was isolated and it was shown to contain the 393bp of the protein-coding sequence and 488bp of the 3' untranslated region. The amino acid sequence deduced from its open reading frame provided independent evidence for the sequence of residues 201-331 of mouse LDH-A subunit (muscle). This cDNA clone was used as a probe to isolate a mouse genomic clone containing a truncated, processed LDH-A pseudogene. This pseudogene showed 81.6% homology at 713 positions compared with the LDH-A cDNA sequence. The divergence of this pseudogene was estimated to have occurred 39 million years ago.
The complete amino acid sequence of calmodulin from wheat germ was determined by isolating and sequencing the cyanogen bromide and tryptic peptides. The protein consisted of 149 amino acid residues and its amino(N)-terminus was blocked with an acetyl group. Wheat germ calmodulin lacked tryptophan and contained 1 mol each of histidine, tyrosine, cysteine, and N epsilon-trimethyllysine residues per mol of the protein. A comparison of its amino acid sequence with that of bovine brain calmodulin indicated that there were eleven amino acid subsitutions other than amide assignments, two insertions and one deletion of amino acid residues in wheat germ calmodulin.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The biosynthesis of prostacyclin in cultured endothelial cells from human umbilical cord vein was inhibited by linoleic acid hydroperoxide at a concentration of 0.1 nmol/ml (in terms of malondialdehyde), while that in cultured smooth muscle cells from rabbit aorta was inhibited only at a higher concentration of the hydroperoxide (5.0 nmol/ml).
To determine the absolute amount of lipid hydroperoxides in biological materials, a simple and sensitive colorimetric method was newly developed, based on the reaction of lipid hydroperoxides with a leucomethylene blue derivative in the presence of hemoglobin. The amount of methylene blue formed was measured by its absorbance at 666 nm to calculate the amount of lipid hydroperoxides using cumene hydroperoxide as external standard. By this method, lipid hydroperoxide concentrations of less than 7.5 nmol/tube were accurately determined.
Explore the source record for details and available documents.
Electron microscopic examination of the effect of linoleic acid hydroperoxide on cultured smooth muscle cells from human umbilical artery revealed that incubation of the cells with 5.0 nmol/ml (in terms of malondialdehyde) of the hydroperoxide for 3 h caused a decrease in the electron density of the mitochondrial matrix and that dilatation of the rough-surfaced endoplasmic reticulum occurred when the cells were incubated with 10 nmol/ml of the hydroperoxide. These concentrations are higher by one order of magnitude than those required for the same effects on cultured endothelial cells from human umbilical vein. A similar difference in susceptibility to injury by linoleic acid hydroperoxide was found between cultured endothelial and smooth muscle cells from fetal calf aorta. The effects of the hydroperoxide on the respiration of these cells paralleled the observed morphological changes.
In a new strain of rat with inherited cataracts, a postnatal increase in serum lipid peroxide level was observed. It reached the maximum on the 13th day after birth. This seems to be a reflection of the increased lipid peroxides in the liver. In accordance with the increase in serum lipid peroxide level, the occurrence of vacuoles in the subcapsular fibers of the posterior region of the lens was observed by electron microscopy, suggesting a relationship between the increase in serum lipid peroxides and the provocation of cataract formation.