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Biomedical subjects

S Miwa

Publications and source records attributed to S Miwa.

At least 307 records · Page 17Linked to original sources
PubMed1984

Hemin-induced conversion of pyruvate kinase isozymes in K562 cells.

The effects of hemin on the conversion of pyruvate kinase (PK) isozymes from the M2-type to the L-type in K562 cells were investigated. Immunofluorescence, ion exchange chromatography, and electrophoretic studies showed that the untreated K562 cells contained only the M2-type PK, while eight to 20 days after induction with hemin, concomitant with hemoglobin F synthesis, L-type PK levels increased while M2-type PK levels decreased. Electrophoretic study revealed three hybrid isozymes of the L-type and M2-type PK. We conclude that the conversion of PK isozymes from the M2-type to the L-type in erythroid precursor cells occurs in the early stage of maturation.

Cell Line↗
PubMed1983

Three families with hereditary hemolytic anemia and pyrimidine 5'-nucleotidase deficiency: electrophoretic and kinetic studies.

Three new variants of pyrimidine 5'-nucleotidase (P5N) found in Japan were studied. They are characterized by slow electrophoretic mobility and a high Michaelis constant for cytidine 5'-monophosphate as has been described in previously reported cases, but are unique with respect to the thermostability test and in pH optima. P5N Kumamoto was thermostable and showed a markedly basic shift in the pH optimum. P5N Nagano was thermolabile and had a normal pH optimum. P5N Kurume was thermostable and showed a basic shift in the pH optimum. These data suggest that these variants have structural gene mutations and that they are clearly distinguished from previously reported cases.

5'-Nucleotidase↗
PubMed1983

alpha Chain and gamma chain abnormal hemoglobins in newborn babies: structural and genetic aspects.

Structural studies and quantitative analyses were conducted on the hemoglobin of 55 newborn babies. Seven alpha chain variants (G-Philadelphia, Montgomery, Inkster, I-Philadelphia, Matsue-Oki, Winnipeg, and O-Indonesia) were present in 26 heterozygous newborns (17 black, eight Caucasian, and one Indonesian). The relative amount of the alpha X containing abnormal Hb F of the Hb G-Philadelphia and Hb Winnipeg babies was less than observed in heterozygous adults, which may indicate a decreased rate of assembly of the alpha X-gamma dimer over that of the alpha X-beta dimer. Of the 29 newborns with gamma chain variants, 16 were Caucasian babies; of these 15 had a Hb A gamma F-Hull heterozygosity and one a Hb G gamma F-Marietta heterozygosity. Six black babies were heterozygous for Hb A gamma F-Texas-I and six for Hb G gamma F-Port Royal. One Japanese baby had a heterozygosity for A gamma F-Iwata and a second was heterozygous for A gamma TF-Yamaguchi. Quantitative analyses of the isolated normal Hb Fo as well as an evaluation of the relative amounts of the Hb Fx in the red cell lysates gave data useful for a speculation of the genetic condition in each of these babies. It was concluded that the babies with the Hbs F-Texas-I, F-Iwata, F-Hull, and F-Marietta were simple heterozygotes with either the G gamma x A gamma/G gamma x A gamma X or the G gamma x A gamma/G gamma X x A gamma genic arrangement. The babies with Hb F-Port Royal had a G gamma x G gamma X/G gamma x A gamma arrangement, which may result from a (to be determined) gene conversion. The newborn baby with Hb F-Yamaguchi has the G gamma x A gamma x/A gamma T-X.-. genic arrangement, suggesting the presence of three distinctly different gamma chain genes of which one, the A gamma T-X gene, produces an A gamma chain (with threonyl at position gamma 75 and an Asn at position gamma 80) at a level usually seen for G gamma rather than A gamma chains. These studies were greatly facilitated by the use of high pressure liquid chromatographic methods.

Amino Acid Sequence↗
PubMed1983

The occurrence of different levels of G gamma chain and of the A gamma T variant of fetal hemoglobin in newborn babies from several countries.

The gamma chain compositions of the fetal hemoglobins of 2453 newborn babies from East Asian countries (1350 babies), from Italy, Yugoslavia, Bulgaria, and Georgia (417 Caucasian babies), and 686 black babies from Georgia were determined by high pressure liquid chromatography. Unusual results for a limited number of babies were confirmed by chemical analyses, and were evaluated further by family studies. Statistical analyses indicated high gene frequencies for the A gamma T chain in Italian (f = 0.237), Yugoslavian and Bulgarian (f = 0.238), and white Georgia babies (f = 0.224), a lower frequency in Japan (f = 0.178), and India (f = 0.173), and particularly in mainland China (f = 0.079). The A gamma T gene frequency in normal (AA) Black babies was 0.102. When a beta S or beta C mutation was also present this frequency was greatly decreased, particularly in babies with the AC condition (f = 0.036). These results suggest the near absence of the A gamma T mutation on the chromosome also carrying the beta C determinant. Most babies had the expected G gamma values which vary between 60 and 80%, but several (mainly black) babies had higher values (between 80 and 90%), while one normal black baby had a G gamma value of (nearly) 100%. This condition may be a form of A gamma +1-thalassemia and has been discussed in detail elsewhere (Blood 58:491-500, 1981). Thirty-five clinically normal (mainly Chinese, Indian, and Japanese) babies had G gamma values of about 40%. Twenty-six babies had A gamma I values of about 60%, while the remaining nine babies had A gamma T and A gamma I chains in a ratio of either 1 to 2 or 1 to 1. Two additional newborns did not produce any G gamma chains, but had only A gamma I chains or A gamma T chains. Family studies failed to indicate a specific hematological abnormality. These unusual ratios between the G gamma and A gamma (either A gamma I or A gamma T) chains have led to speculations regarding possible genetic abnormalities present in these infants.

China↗
PubMed1983

Two cases of phosphofructokinase deficiency associated with congenital hemolytic anemia found in Japan.

Two kindreds of phosphofructokinase (PFK) deficiency associated with congenital nonspherocytic hemolytic anemia and mild myopathy were found in Japan. Both probands had jaundice, gallstones, and slight to moderate degree of exercise intolerance. They showed decreased level of red cell PFK activity and no increase of blood lactate in forearm ischemic exercise test. We studied these probands' red cell PFKs by partial purification and condensation. Muscle type isozyme of PFK in both cases was not demonstrable in starch gel electrophoresis and DEAE-Sephadex chromatography. The clinical symptoms are considered to be due to a defect of muscle type isozyme.

Adult↗
PubMed1983

Red cell adenylate kinase deficiency associated with hereditary nonspherocytic hemolytic anemia: clinical and biochemical studies.

We report here a case of red cell adenylate kinase (AK) deficiency associated with hereditary hemolytic anemia. The proband is a 10-year-old Japanese girl. Her physical and mental development was normal. She has shown moderate to mild hemolytic anemia since the neonatal period and hepatosplenomegaly. The red cell AK activity was 44% of normal. Contents of red cell glycolytic intermediates and adenine nucleotides were normal when compared with a comparable reticulocyte-rich control. Glucose consumption and lactate formation were normal. Hexose monophosphate shunt activity was somewhat lower than that of a comparable reticulocyte-rich control. There were no significant differences in the contents of adenine nucleotides between the younger and older red cells of the patient. Enzymatic characterization by hemolysate revealed that the patient's AK had an increased Michaelis constant for adenosine diphosphate and slight thermal instability. The patient's enzyme migrated approximately half-way between the AK 1 and AK 2 position on starch-gel electrophoresis. The mode of inheritance of this case is obscure. The mechanism of hemolysis might be a structural gene mutation that caused altered electrophoretic and kinetic properties.

Adenosine Diphosphate↗
PubMed1983

Hereditary disorders of red cell enzymes in the Embden-Meyerhof pathway.

Recent advances about hereditary disorders of red cell enzymes in the Embden-Meyerhof glycolytic pathway and Rapoport-Leubering cycle are discussed with a stress on pyruvate kinase deficiency, because it is the most common and most intensively studied disorder among them. Broad genetic heterogeneity exists in all the known erythroenzymopathies. Recently, the primary structure of normal human red cell phosphoglycerate kinase has been determined and single amino acid substitutions of four mutant phosphoglycerate kinases have been clarified by Yoshida et al. These studies allowed analysis of structure-function relationships at the molecular level to be carried out more precisely than was previously possible. It is the consensus of the investigators working in this field that the pathogenesis in three-quarters of the congenital nonspherocytic hemolytic anemia patients remains unknown even after adequate red cell enzyme studies and isopropanol test for unstable hemoglobin have been done. This simply means that much studies remain to be worked out in this field.

Anemia, Hemolytic, Congenital↗
PubMed1983

Chronic myelomonocytic leukemia with a chromosome abnormality (46,XY,20q-) in all dividing myeloid cells: evidence for clonal origin in a multipotent stem cell common to granulocyte, monocyte, erythrocyte, and thrombocyte.

In a typical case of chronic myelomonocytic leukemia (CMML), a chromosome abnormality, 46,XY,20q-, was observed in all the dividing cells including up to 16-ploid cells in the bone marrow and the blood. As the mitotic figures could be easily seen not only in myelomonocytoid cells but also in erythroblasts in the bone marrow smear, it was concluded that all the cell lineages except lymphocytes had the abnormality. The present case will support the view that the leukemic process in CMML affects a multipotent stem cell rather than a granulocyte-monocyte committed stem cell.

Aged↗
PubMed1983

G6PD Sendagi: a new glucose-6-phosphate dehydrogenase variant associated with congenital hemolytic anemia.

A new glucose-6-phosphate dehydrogenase (G6PD) variant associated with chronic nonspherocytic hemolytic anemia was discovered. It was found in a 2-year-old male who had a hemolytic crisis after an upper respiratory tract infection. The enzyme activity of the variant was 8.4% of that of the normal enzyme. The enzymatic characteristics were slower than normal anodal electrophoretic mobility, low Km G6P, normal Km NADP, increased utilization of substrate analogues, high Ki NADPH, decreased heat stability, and an alkaline pH optimum. From these results, this was considered to be a new variant and was designated G6PD Sendagi.

Anemia, Hemolytic, Congenital↗
PubMed1983

Change of pyruvate kinase isozymes from M2- to L-type during development of the red cell.

The relationship between erythroid cell maturation and the change of pyruvate kinase (PK) isozymes was studied using fluorescent antibody techniques. The fluorescence of M2-type PK was strongest in the proerythroblast stage, and then steeply declined with red cell maturation so that only weak fluorescence was seen in orthochromatic erythroblasts. On the other hand, the fluorescence of L-type PK was seen throughout the maturation of the erythroblasts, with stronger fluorescence in the basophilic or polychromatic erythroblasts than in proerythroblasts.

Bone Marrow↗
PubMed1983

Analysis of human erythrocyte 5'-nucleotidases in healthy individuals and a patient deficient in pyrimidine 5'-nucleotidase.

Electrophoretic and quantitative analysis of pyrimidine 5'-nucleotidase in human erythrocytes from healthy individuals and a patient deficient in pyrimidine 5'-nucleotidase, using a range of substrates, has shown that the patient has a marked deficiency with UMP, CMP and dCMP as substrates but near normal levels of activity with dUMP and dTMP as substrates. The observations suggest that two separate structural gene loci coding for distinct 5'-nucleotidases with similar electrophoretic mobility exist in man. The genetic determination of these enzymes seems therefore to be homologous with that found in rodents.

5'-Nucleotidase↗
PubMed1983

Phosphofructokinase deficiency associated with congenital nonspherocytic hemolytic anemia and mild myopathy: biochemical and morphological studies on the muscle.

Enzymatic and electron microscopical studies were performed on the muscle of a proband with phosphofructokinase deficiency. Enzymatic studies showed that muscle phosphofructokinase activity of the proband was decreased to about a half of normal. This enzyme was quite thermolabile and had low affinity for fructose 6-phosphate. Electron microscopical studies showed the accumulation of glycogen granules beneath the sarcolemma and between the myofibrils in spite of a lack of accumulation of the intermediates before the step of phosphofructokinase. The proband's clinical symptoms, i.e., hemolytic anemia and myopathy, were considered to be due to the unstable, mutant, muscle-type phosphofructokinase in the red blood cells and muscle.

Adult↗