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Biomedical subjects

R Sasaki

Publications and source records attributed to R Sasaki.

At least 289 records · Page 16Linked to original sources
PubMed1984

Isolation of human erythropoietin with monoclonal antibodies.

Human erythropoietin was isolated from urine of aplastic anemic patients in a high yield with a simple purification procedure using an immunoadsorbent column of monoclonal antibodies and a Sephadex G-100 column. About 6 mg of erythropoietin was isolated from 700 liters of urine and the specific activity was estimated to be 81,600 units/mg of protein with an in vivo 59Fe incorporation assay method, using starved rats. Activity measurement of the extracts from sliced gels after sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the Western blotting technique revealed heterogeneity of the isolated erythropoietin, which is probably caused by variable amounts of carbohydrates attached to the polypeptide chain. Thirty amino acids in the NH2-terminal portion of the isolated hormone were sequenced.

Anemia, Aplastic↗
PubMed1984

Significance of the equilibrium constant between serum ascorbate radical and ascorbic acids in man.

The spin concentration of ascorbate radical in human serum was examined and the existence of the stable equilibrium between the spin concentration of serum ascorbate radical and concentrations of ascorbic acids in healthy subjects was found. The value of the equilibrium constant was independent of age and sex. The administration of ascorbic acid caused the convergence of these values which were scattered within certain ranges in healthy volunteers. The values of the equilibrium constant increased in many patients with various diseases and returned to normal level with improvement of symptoms. These indicate that the equilibrium constant can be used as a clinical index to reflect metabolic state involving ascorbic acid as the radical scavenger.

Ascorbic Acid↗
PubMed1984

Detection of terminal deoxynucleotidyl transferase (TdT)-positive leukemia cells by an immunoperoxidase staining.

Several conditions for the immunoperoxidase staining on terminal deoxynucleotidyl transferase (TdT) were surveyed in leukemic cells. Fixation of the slides in methanol containing 0.03% hydrogen peroxide for 30 min obliterated endogenous peroxidase completely. Pretreatment of the slides with normal goat serum diminished nonspecific staining effectively. Replacement of rabbit anti-TdT serum with non-immune rabbit IgG gave negative staining in the slides from TdT+ cases. The presence or the absence of TdT and % TdT+ cells determined by this method were in concordance with those assessed by immunofluorescence (IF) or by biochemical assay. Therefore, the immunoperoxidase staining provides an easy and dependable method to survey TdT by bright-field microscopy. The peroxidase+ small granules were detected in the nucleus of the blasts from TdT+ ALL cases. However, in two of four cases with CML in blast crisis peroxidase+ granules were distributed in the cytoplasm as well as in the nucleus. This finding suggests that blasts of some CML cases in blast crisis have phenotypic characteristics similar to some population of TdT+ cells in thymocytes.

Adult↗
PubMed1984

Specific immobilization of an enzyme by monoclonal antibody: immobilization of guinea pig liver transglutaminase.

A simple method for enzyme immobilization using a monoclonal antibody raised against the enzyme was studied, taking guinea pig liver transglutaminase as an example. This method consists of two steps; a conjugation of monoclonal antibodies, which bind with the enzyme without inhibitory effect on the activity, with agarose gel bead supports, and immobilization of enzyme proteins onto the conjugated monoclonal antibodies through the antigen-antibody immunoreaction. The following are the advantages of this method. (i) Activity recovery after the immobilization was very high, (ii) enzyme proteins in crude enzyme preparation could be immobilized specifically, and (iii) immobilized enzymes could be replaced easily by fresh enzyme proteins through a urea-buffer treatment.

Acyltransferases↗
PubMed1984

Hybridomas for production of monoclonal antibodies to human erythropoietin.

Human urinary erythropoietin has been highly purified by a combination of conventional purification methods and immunoadsorbent columns packed with hybridoma-produced antibodies against contaminants that seemed difficult to separate from erythropoietin by the usual means. By using the partially purified erythropoietin as an antigen, three hybridoma clones have been obtained that secrete monoclonal antibodies against erythropoietin. One of the clones has been quite stable, with a rapid growth rate and high production of antibody. Western blotting technique with monoclonal antibodies revealed occurrence of two species of erythropoietin. The monoclonal antibody will be useful as a probe for the purification of erythropoietin and for further studies of the hormone and its mechanism of action.

Animals↗
PubMed1983

A family of hereditary stomatocytosis associated with normal level of Na+-K+-ATPase activity of red blood cells.

A rare familial case of hereditary stomatocytosis with hemolytic anemia, increased autohemolysis, increased osmotic fragility, and shortened erythrocyte survival is described. The erythrocytes were abnormally permeable to sodium and potassium. In addition, "Na-K pump" rate of the red blood cells was increased, while Na+-K+-ATPase, Mg2+-ATPase and Mg2+-Ca2+-ATPase activities were within normal limits. Splenectomy induced marked improvement of anemia.

Anemia, Hemolytic, Congenital↗
PubMed1983

Role and induction of 2,3-bisphosphoglycerate synthase.

2,3-Bisphosphoglycerate accumulates in mammalian erythrocytes, where it facilitates the supply of oxygen to the tissues by binding to hemoglobin. Regulatory properties of 2,3-bisphosphoglycerate synthase and phosphatase are discussed. The 2,3-bisphosphoglycerate concentration was shown to rise linearly along with the hemoglobin level during erythroid differentiation. The accumulation of 2,3-bisphosphoglycerate was primarily attributable to an increase in 2,3-bisphosphoglycerate synthase. Antibody-binding studies showed that the increased activity is achieved solely through an increase in the amount of enzyme. It was shown that 2,3-bisphosphoglycerate synthase was synthesized in nucleated erythroid precursor cells and also in anucleated reticulocytes. The mRNA of this protein appears to be fairly stable in reticulocytes. Coordinate expression of hemoglobin and 2,3-bisphosphoglycerate synthase was found during dimethylsulfoxide-induced differentiation of Friend erythroleukemia cells. 2,3-Bisphosphoglycerate rose concomitantly.

2,3-Diphosphoglycerate↗
PubMed1983

Ascorbate radical and ascorbic acid level in human serum and age.

Free radical in human serum was observed by an electron spin resonance (ESR) technique and was assigned to ascorbate radical. Quantitative estimation revealed that the ESR intensity could be used as an expedient mean. The ESR intensity of ascorbate radical, the concentrations of total ascorbic acid and oxidized form of ascorbic acid were determined on sera of 200 healthy individuals whose ages ranged from 12 to 96 years. The ESR intensity as well as the concentrations of total and oxidized form of ascorbic acid declined with age. There were significant correlations between the ESR intensity and the concentrations of total and oxidized form of ascorbic acid. From these results, the clinical significance of the concentrations of total ascorbic acid, ascorbate radical and the oxidized form was discussed in relation to age.

Adolescent↗
PubMed1983

Effects of ceruloplasmin and the haptoglobin-hemoglobin complex on the oxygen-dependent reduction in growth of human diploid fibroblasts in serum-free, albumin containing medium.

We examined that growth-promoting activity of two different human albumin (HSA) preparations for human diploid fibroblasts in serum-free RITC 80-7 medium. The activity of one preparation (sample A) was affected markedly by environmental oxygen, whereas the other (sample B) was little affected. Sample B contained ceruloplasmin (Cp) and haptoglobin (Hp) as impurities. To detect the generation of superoxide anion in the media the amount of reduction of cytochrome c that is inhibited by superoxide dismutase (SOD) was determined. In an aerobic environment it was relatively large in comparison with reduction inhibited in a hypoxic environment. Reduction in the sample A with HSA-supplemented medium was relatively large in comparison with that in sample B with HSA-supplemented medium. The reduction of cytochrome c also was inhibited by Cp (25 mg/l) and catalase (4000 units/ml). Moreover, SOD, Cp, catalase and Hp.Hb (but not Hp) partially prevented oxygen-dependent reduction in growth in an aerobic environment when added to sample A HSA-supplemented medium. These results suggest that Cp and Hp.Hb act as an antioxidants in culture.

Blood Protein Electrophoresis↗
PubMed1983

Influences of sex and age on serum ascorbic acid.

The concentrations of total ascorbic acid, reduced and oxidized forms of ascorbic acid, the ESR intensity of ascorbate radical, and the ratio of oxidized form of ascorbic acid to total ascorbic acid (DAsA/AsA) were estimated on 217 healthy controls, whose ages ranged from 12 to 96 years, in order to examine influences of sex and age. The concentration of total ascorbic acid was higher in females than in males throughout all age classes, but the oxidized form did not show a sex difference. Then it was found that the reduced form was higher in females than in males throughout all age classes. The concentrations of total ascorbic acid and reduced and oxidized forms of ascorbic acid, and the ESR intensity declined with age, but the DAsA/AsA ratio increased with age.

Adolescent↗
PubMed1983

Quality deterioration of winged bean during storage.

Seeds of winged bean (Psophocarpus tetragonolobus) were stored under four different sets of conditions; 65% relative humidity (RH) at 5 degrees C, 35% RH at 37 degrees C, 65% RH at 37 degrees C, and 85% RH at 37 degrees C. After storage for three and five months, samples were taken out to explore quality changes during storage. The germination capacity decreased during storage at high temperatures. Although little change was found in content in extractable oil, a decrease in the iodine value and an increase in the acid value and in the TBA value were significant during storage at high temperature and high moisture, indicating deterioration of oil. Aldehyde in defatted bean extract increased under all conditions for storage. Protein extractability was greatly reduced at 36 degrees C and 85% RH, while no reduction was observed at other conditions.

Fabaceae↗