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Biomedical subjects

Y Ueda

Publications and source records attributed to Y Ueda.

At least 1,099 records · Page 61Linked to original sources
PubMed1979

Hydrolysis of low molecular weight isomaltosaccharides by a p-nitrophenyl-alpha-D-glucopyranoside-hydrolyzing alpha-glucosidase from a thermophile, Bacillus thermoglucosidius KP 1006.

A p-nitrophenyl-alpha-D-glucopyranoside-hydrolyzing alpha-glucosidase of a thermophile, Bacillus thermoglucosidius KP 1006, was purified to an electrophoretically-homogeneous state. Its molecular weight was estimated as 60 000 by gel electrophoresis. The molecular activity (ko) and the Km value at 60 degrees C and pH 6.8 for p-nitrophenyl-alpha-D-glucopyranoside were 233 s-1 and 0.24 mM, respectively. The enzyme cleft the non-reducing terminal alpha-1,6-glucosidic bonds of isomaltose, panose, isomaltotriose, isomaltotetraose, and isomaltopentaose. The ko values were 72.4, 194, 208, 233 and 167 s-1, and the Km values were 3.3, 9.5, 11, 13 and 21 mM, respectively. Each isomaltosaccharide was hydrolyzed to glucose by the cleavage of single glucose units from its nonreducing end. The present study suggests that the enzyme is an oligo-1,6-glucosidase (dextrin 6-alpha-glucanohydrolase, EC 3.2.1.10) and an exo-glucosidase.

Bacillus↗
PubMed1979

Orthopoxvirus strains defective in surface antigen induction.

Various strains of vaccinia, variola, whitepox, monkeypox and cowpox viruses were examined for their capacity to induce a specific early antigen detectable on the surface of infected cells. The Elstree strain of vaccinia, two strains of variola minor and white variants of cowpox and monkeypox viruses lacked the capacity to induce the antigen. Variation of the parent cowpox and monkeypox viruses to white variants was always accompanied by the loss of the antigen-inducing capacity.

Animals↗
PubMed1979

delta-Aminolevulinic acid synthetase in erythroblasts of patients with pyridoxine-responsive anemia. Hypercatabolism caused by the increased susceptibility to the controlling protease.

Properties of delta-aminolevulinic acid synthetase in erythroblasts of patients with pyridoxine-responsive anemia were investigated with special reference to the protease in mitochondria of erythroblasts. delta-Aminolevulinic acid synthetase activity in erythroblasts of patients with this disease before treatment was extremely decreased, whereas it gradually increased in parallel with the improvement of anemia by the therapy with pyridoxal phosphate. The amount of apo-delta-aminolevulinic acid synthetase in erythroblasts before treatment was also extremely diminished. Apparent affinity to pyridoxal phosphate of the apo-delta-aminolevulinic acid synthetase obtained from erythroblasts of the patients was almost the same as that of normal controls. The activity of a new protease which is considered to be engaged in the regulation of delta-aminolevulinic acid synthetase levels in mitochondria of erythroblasts was shown to be in normal range in erythroblasts of the patients. On the other hand, apo-delta-aminolevulinic acid synthetase obtained from the patients was extremely sensitive to the protease. These results indicate that disturbance of heme synthesis characteristic to pyridoxine-responsive anemia could be ascribed to the hypercatabolism of delta-aminolevulinic acid synthetase caused by the increased susceptibility to the controlling protease in erythroblasts.

5-Aminolevulinate Synthetase↗
PubMed1979

[Multiple osteosarcoma in spontaneously hypertensive rats (author's transl)].

For period from 1971 to 1975, 18 cases of osteosarcoma were experienced among 9132 spontaneously hypertensive rats. The onset was at 72 to 145 days of age and death occurred before 423 days of age. The tumors were multiple being distributed in the skull (11 of 14 cases), caudal vertebrae (8 of 14 cases), and fore- and hind-limb. All the tumors were mainly composed of sarcomatous tissue with some osteoid and cartilage. Metastasis was never observed. Serum A1-P levels of tumor bearing animals were 2 times higher than those without tumor. Bronchiectasis and abscess formation of submaxillary lymph nodes were noted in most affected animals.

Alkaline Phosphatase↗
PubMed1979

An increased Bohr effect in sickle cell anemia.

Recent findings that hemoglobin S gelation and sickling are pH-dependent and also influence oxygen affinity suggested that the red cells containing this hemoglobin variant might show an abnormal Bohr effect. We therefore studied the effects of pH variation on the in vitro oxygen affinity of whole blood from persons with sickle cell anemia (SS) and normal donors (at 37 degrees C and constant carbon dioxide tension of 40 mm Hg). The Bohr effect in SS blood was greatly increased only between blood pH 7.4 and 7.2 (cell pH 7.2 and 7.0, a shift that strongly affects gelation), with delta log p50/deltapH= - 0.92 to -0.99 (normal = -0.42 to -0.46). Thus a drop in SS blood pH below 7.4 in tissue capillaries yields twice the normal decrease in oxygen affinity and a large release of oxygen from red cells, whose risk of sickling is high. Even mild transient acidosis would seem hazardous for patients with sickling disorders.

Anemia, Sickle Cell↗
PubMed1979

Hemoglobin Crete (beta 129 ala leads to pro): a new high-affinity variant interacting with beta o -and delta beta o -thalassemia.

Hemoglobin Crete, beta129 (h7)ala leads to pro, is a new mutant hemoglobin (Hb) with high oxygen affinity that was discovered in a Greek family in various combinations with beta- and deltabeta-thalassemia. The propositus, who presented an unusual clinical picture of an "overcompensated" hemolytic state, with erythrocytosis, splenomegaly, abnormal red cell morphology, and marked erythroid hyperplasia, appeared doubly heterozygous for Hb Crete and deltabeta-thalassemia. His red cells contained 67% Hb Crete and 30% Hb F, and the combination of these two hemoglobins resulted in a blood P50O2 of 11.2 mm Hg. A brother with Hb Crete trait (38% Hb Crete, 56% Hb A, blood P50O2 23.0 mm Hg) did not have significant erythrocytosis. Purified Hb Crete was heat-unstable and exhibited a high oxygen affinity, and a normal Bohr effect. We postulate that the beta 129 proline substitution disrupts the H helix, perturbing nearby residues involved in alpha 1 beta 1 contact sites of the Hb tetramer.

Adult↗
PubMed1978

Sickling rates of human AS red cells infected in vitro with Plasmodium falciparum malaria.

The kinetics of sickling of malaria-infected red cells from humans with sickle cell trait were studied in vitro in an attempt to obtain direct experimental evidence for a selective advantage of the hemoglobin S heterozygote in a malarious region. The sickling rates of cells infected with Plasmodium falciparum and of non-infected cells were studied both in the total absence of oxygen (by dithionite addition) and at several different concentrations of oxyhemoglobin which might obtain in vivo. In all cases, red cells containing small plasmodium parasite forms (ring forms) sickled approximately eight times as readily as uninfected cells. Cells containing large parasitic forms (trophozoites and schizonts) appeared to sickle less readily than uninfected cells, by light microscopy criteria, but electron micrographs demonstrated the presence of polymerized deoxyhemoglobin S with a high frequency. It is concluded that enhanced sickling of plasmodium-infected AS cells may be one mechanism whereby the hemoglobin S polymorphism is balanced in favor of the heterozygote.

Anemia, Sickle Cell↗
PubMed1978

Studies on Cotia virus--an unclassified poxvirus.

This paper is a report of studies on Cotia virus; this had been first isolated in 1965 in Brazil and was subsequently shown to be a poxvirus. Cotia virus grew in a wide range of cell cultures and on the chick chorioallantois (CAM), Its growth characteristics are similar to those of other poxviruses. Microscopy showed virus factories or type B inclusions appearing before infectious progeny virus could be demonstrated. Type A inclusions appeared later, after development of progeny virus; these were shown by electron microscopy to differ from the type A inclusions of cowpox and other poxviruses and they have been termed Cotia bodies. Immunofluorescent staining also showed ring structures which appeared before the development of Cotia bodies. The growth of Cotia virus in human embryo lung (HEL) cells was sensitive to inhibitors of DNA and protein synthesis but was resistant to a concentration of rifampicin which inhibited vaccinia virus. Sharing of antigens between the Cotia virus and vaccinia virus was shown by gel precipitation tests and immunofluorescent staining. There was no cross neutralization between Cotia virus and vaccinia virus nor did anti-Cotia sera neutralize representatives of other poxvirus groups.

Brazil↗