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Biomedical subjects

A Yoshida

Publications and source records attributed to A Yoshida.

At least 1,189 records · Page 66Linked to original sources
PubMed1980

Membrane abnormality in red blood cells with weak type B expression.

The mechanisms of unusually weak blood group (A and B) expressions are not yet well understood. We examined properties of blood group galactosyltransferase (B-enzyme) and characteristics of red cell membrane components obtained from family members with A2Bm character. B-enzyme activity of the A1Bm plasma is in normal range, and kinetic properties (i.e., Km for UDP-Gal, Km for 2'-fucosyllactose, and pH optima) of B-enzyme from the A1Bm subjects are identical to that of normal B-enzyme. When A1Bm red cell were incubated with UDP-Gal and B-enzyme, the cells became strongly agglutinable with anti-B. When A1Bm membranes were incubated with B-enzyme or A-enzyme (i.e., blood group N-acetylgalactosaminyltransferase) and the appropriately labeled nucleotide sugar (UDP-Gal3H for B-enzyme and UDP-GalNAc3H for A-enzyme), significant incorporation of the sugar was observed. The amounts of the sugar incorporated into A1Bm membranes were about 40%-50% of that incorporated into O membranes at saturation, indicating that about one-half of H-sites remained unglycosylated in A1Bm red cells. Examination of radioactive components by isoelectric focussing revealed that the labeled components of A1Bm membranes were distinctively different from that of O membranes. Therefore, one can conclude that the weak B expression is not due to direct mutation of ABO locus, but due to a secondary consequence of genetic abnormality of a membrane component (or components) associated with blood group substances.

ABO Blood-Group System↗
PubMed1980

A phosphoglycerate kinase variant, PGK Uppsala, associated with hemolytic anemia.

An X-linked PGK deficiency is known to be associated with chronic nonspherocytic hemolytic anemia and mental disorders in man. The glycolytic intermediates and red cell enzymes of a Swedish male subject with these genetic abnormalities were examined. The PGK activity of red blood cells from the subject was about 10% of normal, although the activities of other red cell enzymes were normal or above normal. Significant accumulation of 2,3-DPG and 2-phosphoglycerate in the subject's red cells was observed. The PGK from the subject was associated with lower affinity to both ATP and 3-phosphoglycerate and with an increased rate of degradation in red cells and also in vitro. The immunological neutralization test suggested that the specific enzyme activity of the variant enzyme was significantly lower than normal. The variant enzyme moved faster than the normal toward the anode in starch-gel electrophoresis. These results indicate that the variant is a result of structural mutation, and it is designated PGK Uppsala.

Anemia, Hemolytic, Congenital Nonspherocytic↗
PubMed1979

Structural comparison of hexosaminidases in primates.

1. beta-Hexosaminidase (hex) structure was compared in various primates, using thin-layer isoelectric focusing on polyacrylamide gels and quantitative microcomplement fixation. 2. Isoelectric focusing revealed no intraspecies differences and similar interspecies patterns. 3. Hex A and B are evolving at a moderate, but equal, rate and in a manner consistent with accepted phylogenetic patterns. 4. Quantitative microcomplement fixation revealed a closer homology between human hex A and chimpanzee A or human hex B and chimpanzee hex B than between human hex A and human hex B.

Animals↗
PubMed1979

Metal-binding and detoxification effect of synthetic oligopeptides containing three cysteinyl residues.

Metallothionein is a naturally occurring metal-binding protein with high cysteine content. Oligopeptides containing three cysteinyl residues and having amino acid sequences analogous to portions of this protein were synthesized by the solid-phase method. Strong affinity of the synthetic peptides to Cd2+ and Zn2+ was observed, and the dissociation constants of the peptide-metal complexes were 2-4 orders of magnitude lower than those of cysteine-metal and dithioerythritol-metal complexes. Effectiveness of detoxification of the peptides against Cd toxicity was demonstrated by the higher survival rates of mice treated with the peptides and by the neutralization of Cd toxicity by the peptides in tissue cultures.

Cations, Divalent↗
PubMed1979

Effectiveness of dietary iron and ascorbic acid in the prevention and cure of moderately long-term lead toxicity in rats.

The protective and curative effects of high levels of dietary iron and ascorbic acid on moderately long-term toxicity in rats were examined. In rats fed a diet containing 500 ppm of lead for 56 days, growth retardation, reduction of food consumption, anemia, hypertrophy of the kidney and accumulation of lead in the bone and kidney were observed, however, activities of alkaline phosphatase and GOT in the plasma did not change. Addition of 400 ppm of iron and 1% of ascorbic acid to the lead containing diet prevented the growth depression, reduction of food consumption, anemia and decreased the accumulation of lead in tissues. When these compounds were added to the lead containing diet for 18 days after feeding the lead diet alone for 38 days, almost no curative effects on lead toxicity were observed. In contrast to cadmium toxicity, dietary iron and ascorbic acid have no curative effect on established lead toxicity.

Animals↗
PubMed1979

Effect of dietary supplementation of iron and ascorbic acid on lead toxicity in rats.

In our laboratory, the protective and therapeutic effects of surplus dietary iron and ascorbic acid on cadmium toxicity in rats have been studied and in this experiment, an effect of surplus iron and ascorbic acid on lead toxicity was examined. In young rats ingesting a diet containing 500 ppm of lead, growth retardation and anemia were observed. Suplementation of 400 ppm of iron and 1% of ascorbic acid to the lead containing diet prevented the growth depression and anemia and caused reductions of concentrations of lead in the kidney and tibia. Whereas, addition of 50 ppm of cadmium to the lead containing diet aggravated the growth retardation and anemia, but reduced the concentrations of lead in the kidney and tibia. Dietary supplementation of iron to the lead containing diet prevented the growth depression and anemia and reduced the accumulation of lead in the kidney, however the supplementation of ascorbic acid alone did not show any ameliolative effects. Rats were fed the lead containing diet and then transferred to the basal diet with or without iron and ascorbic acid. Recoveries from the growth retardation and anemia were not observed in rats within a week after the transfer to the non-lead diet with or without iron and ascorbic acid. These results suggest that iron prevents the growth depression and anemia in rats ingesting lead by an inhibition of lead asborption.

Animals↗
PubMed1979

Studies on the nuclear binding of steroid hormone-receptor complex; binding of liver and thymus dexamethasone-receptor complex and prostate dihydrotestosterone-receptor complex to nuclei from various tissues.

To examine the binding specificity of steroid hormone-cytoplasmic receptor complexes to nuclei, binding of 3H-dexamethasone (Dex)-liver, 3H-Dex-thymus and 3H-dihydrotestosterone (DHT)-prostate receptor complexes to nuclei from liver, prostate, thymus, spleen and kidney was studied. It was observed that a significant amount of steroid-receptor complexes was bound to any nuclei used in the present study and the extent of the binding of receptor complexes to nuclei from homologous tissues was not always greater than that to nuclei from heterogenous tissues. However, a significant portion of the 3H-Dex-liver and 3H-DHT-prostate receptor complexes was not absorbed by nuclei from kidney, spleem, and thymus, and the unabsorbed complexes were efficiently bound to liver and prostate nuclei. The results obtained indicate that two types of receptor complex with regard to nuclear binding were present in cytosols of liver and prostate; one binds to nuclei from kidney, spleen, thymus, liver and prostate and the other does not bind to nuclei from kidney, spleen and thymus but does bind to nuclei of liver and prostate. The latter type of receptor complex was not observed in the cytosol from the thymus.

Animals↗
PubMed1979

Effect of diets supplemented with amino acids on intestinal sucrase and leucine aminopeptidase activities in rats.

In order to investigate the relationship between dietary amino acids and protein, and activities of intestinal sucrase [EC 3.2.1.26] and leucine aminopeptidase [EC 3.4.11.1, LAPase] in rats, the effect of supplementation of amino acids into a protein-free diet and a low casein diet containing sucrose as the carbohydrate source on these enzyme activities was studied. The segmental weights of the small intestine and its mucosa of rats fed the protein-free diet supplemented with L-methionine or with L-methionine and L-threonine at 0.1 or 0.2% levels were significantly higher than those of rats fed the protein-free diet or one supplemented with L-glutamic acid, but there was no difference in the segmental activities of the sucrase and LAPase among rats fed these diets. On the other hand, the supplementation of methionine or methionine plus threonine to the 5% or 10% casein diet produced remarkable increases in the segmental weights of the small intestine and its mucosa as well as in the segmental activities of the sucrase and LAPase. There was no difference between the segmental sucrase activity of rats fed the 10% casein diet supplemented with 0.2% methionine ad libitum and that of rats fed this diet under restricted feeding conditions, although the segmental LAPase activity was affected by the amount of food consumed.

Amino Acids↗