Search PubMed⌕ Search

Biomedical subjects

S Miwa

Publications and source records attributed to S Miwa.

At least 343 records · Page 19Linked to original sources
PubMed1981

Thirteen cases of pyruvate kinase deficiency found in Japan.

Thirteen cases of pyruvate kinase (PK) deficiency, considered to be heterozygous for different PK mutants because of no consanguinities in their parents, were characterized by the International Committee for Standardization in Haematology (ICSH) recommended methods. These deficiency cases are named PK "Kagoshima," PK "Kyoto," PK "Takamatsu," PK "Abeno," PK "Kobe," PK "Marugame," PK "Hoenzaka," PK "Osaka," PK "Motomachi," PK "Gifu," PK "Hiroshima" PK "Matsumoto," and PK "Tama." The characteristics of mutant PK enzymes suggest that the cause of chronic hemolysis depends mainly on decreased affinity for phosphoenolpyruvate, thermolability, increased inhibition by adenosine triphosphate, and low activation by fructose-1, 6-diphosphate.

Adolescent↗
PubMed1981

A case of lead intoxication: clinical and biochemical studies.

A 23-year-old Japanese male with severe lead intoxication accompanied by hemolytic anemia was studied. The patient had taken 12 g to lead in about a month. He had moderate hemolytic anemia (Hb 8.9 g/100 ml) with reticulocytosis ranging from 2.5 to 11.7%. Peripheral blood smear showed nucleated red cells (42/200 white blood cells) and marked basophilic stippling in the red cells. Activities of erythrocyte enzymes were either normal or increased except for pyrimidine 5'-nucleotidase (P5N) and delta-aminolevulinic acid dehydratase (ALA-D) both of which were found to be decreased, being 48.8% and 4.1% of the normal controls respectively. Erythrocyte reduced glutathione (GSH) was high (145.6 mg/100 ml RBC). Erythrocyte pyrimidine nucleotides were accumulated up to 10.2% of total nucleotides. The level of lead in peripheral blood was 112 microgram per 100 ml blood. Ca2+-Na2-EDTA was given to the patient as treatment. The level of lead in the blood decreased gradually and hemolytic anemia improved. Basophilic stippling in the red cells disappeared. These results confirmed the findings of Valentine et al [1] that lead-induced deficiency of P5N resulted in basophilic stippling and hemolytic anemia just like hereditary hemolytic anemia due to P5N deficiency.

5'-Nucleotidase↗
PubMed1981

Two cases of red cell aldolase deficiency associated with hereditary hemolytic anemia in a Japanese family.

Two cases of red cell aldolase deficiency associated with congenital nonspherocytic hemolytic anemia are reported. The proband is a fourteen-month-old Japanese boy. Consanguineous marriage was not proven but probable in this family, as the parents were born in the same small island. The proband had moderate to mild anemia aggravated by upper respiratory infections, 1 cm hepatomegaly and 2.5 cm splenomegaly, but was unremarkable in other respects and has thus far not shown mental or growth retardation. He did not have dysmorphic features. The red cell aldolase activity was 6% of the normal mean. The enzyme was unstable with respect to heat, and Km for fructose 1,6-diphosphate (F-1,6-DP) was high. The parents and other heterozygotes showed intermediate activity between that of the proband and that of normal subjects. Red cell F-1,6-DP concentration in this case was remarkably increased. Red cell glucose consumption, and lactate formation, as well as hexose monophosphate shunt activity, were decreased as compared with a comparable reticulocyte-rich hereditary spherocytosis patient. Hexose monophosphate dehydrogenase by a high concentration of F-1,6-DP in his red cells. As a result of family study, another homozygous aldolase deficiency case associated with hemolytic anemia was found. He is 13 years old and a nephew of the proband's paternal grandmother. His hemolytic anemia also is moderate to mild and aggravated by upper respiratory infections. He does not seem to have mental or growth retardation, nor does he possess dysmorphic features.

Adolescent↗
PubMed1981

Glucose 6-phosphate dehydrogenase variants: a unique variant (G6PD Kobe) showed an extremely increased affinity for galactose 6-phosphate and a new variant (G6PD Sapporo) resembling G6PD Pea Ridge.

Two new glucose 6-phosphate dehydrogenase (G6PD) variants associated with chronic nonspherocytic hemolytic anemia were discovered, G6PD Kobe was found in a 16-year-old male associated with hemolytic crisis after upper respiratory infection. The enzyme activity of the variant was about 22% of that of the normal enzyme. The main enzymatic characteristics were slower than normal anodal electrophoretic mobility, high Km G6P, increased thermal-instability, an acidic pH optimum, and an extremely increased affinity for the substrate analogue, galactose 6-phosphate (Gal-6P). G6PD Sapporo was found in a 3-year-old male associated with drug-induced hemolysis. The enzyme activity was extremely low, being 3.6% of normal. In addition, this variant showed high Ki NADPH and thermal-instability. G6PD Kobe utilized the artificial substrate Gal-6P effectively as compared with the common natural substrate, glucose 6-phosphate. In G6PD Sapporo, NADPH could not exert the effect of product inhibition. The structural changes of these variants are expected to occur at the portions inducing conformational changes of the substrate binding site of the enzyme.

Adolescent↗
PubMed1981

Use of cultured lymphoblastoid cells for the study of abnormal enzymes: molecular abnormality of a phosphoglycerate kinase variant associated with hemolytic anemia.

A phosphoglycerate kinase (PGKase: ATP:3-phosphoglycerate 1-phosphotransferase, EC 2.7.2.3; X chromosome-linked) variant, PGKase-Tokyo, is associated with enzyme deficiency, nonspherocytic hemolytic anemia, and neurological disturbances. Because a sufficient amount of the patient's erythrocytes was not available, the variant enzyme was purified to homogeneity from the cultured lymphoblastoid cells of the patient. The enzyme activity of the variant lymphoblastoid cells was about 16% of that of the normal lymphoblastoid cells. PGKase-Tokyo, compared to the normal enzyme, had a lower specific activity (31% of normal in the backward reaction and 15% of normal in the forward reaction), higher than normal Michaelis constants for ATP and 3-phosphoglycerate, a more acidic pH optimum, and increased thermal instability. Microscale peptide mapping analysis revealed that the structural abnormality of PGKase-Tokyo is a single amino acid substitution from valine to methionine at position 266. Thus, the use of the cultured lymphoblastoid cells is proven to be useful for the study of structural and functional abnormalities of mutant enzymes.

Amino Acids↗
PubMed1981

Red-cell enzyme activities and properties of mutant pyruvate kinase after 1-year storage in a -80 degrees C freezer.

Red cells from 5 healthy adults and an unstable mutant pyruvate kinase (PK), PK Maebashi, were stored for 12 months in a -80 degrees C freezer. With an exception of triosephosphate isomerase and phosphoglycerate kinase activities, normal red-cell enzyme activities remained essentially unchanged. Mutant PK was characterized by the methods recommended by the International Committee for Standardization in Haematology (ICSH). Normal control and PK Maebashi remained essentially unchanged in their characteristics after storage in a -80 degrees C freezer for 12 months. These results indicate that the red cells stored over a long term in a -80 degrees C freezer can be used for the study of unstable mutant PK.

Blood Preservation↗
PubMed1981

Hemoglobin Tottori (alpha 59[E8] glycine replaced by valine).

A new electrophoretically silent, unstable hemoglobin was discovered in a Japanese family. Isolation of the abnormal chain and chemical analyses demonstrated a previously unreported amino acid substitution, alpha 59[E8] glycine replaced by Valine. The new variant has been named Hb Tottori.

Adult↗
PubMed1981

Hemoglobin Miyashiro (beta 23[B5] val substituting for gly) an electrophoretically silent variant discovered by the isopropanol test.

A new unstable hemoglobin was discovered in a Japanese boy without any signs of hemolytic disease during screening of patients by the isopropanol test. The abnormal hemoglobin was found in three generations. This slightly unstable hemoglobin could not be separated from Hb A by electrophoresis. All carriers showed an increased whole blood oxygen affinity. Structural studies demonstrated a previously unreported amino acid substitution, beta 23[B5] valine substituting for glycine. This new unstable variant has been named Hb Miyashiro.

Adolescent↗
PubMed1981

Studies on pyruvate kinase deficiency, pyrimidine 5-'nucleotidase deficiency and adenosine deaminase overproduction.

Using recently established ICSH recommended methods, red cell pyruvate kinases (PK) of 20 patients with PK deficiency were characterized and 7 new PK variants were found. Analysis of partially purified red cell pyrimidine 5'-nucleotidase (P5N) from a patient with P5N deficiency provided the evidence for a structural alteration of the enzyme protein. Red cell adenosine deaminase (ADA) from a patient with 40-fold increase in ADA activity associated with hemolytic anemia was purified and compared with that from normal subjects. It is most conceivable that the increased ADA activity represents increased amount of structurally normal enzyme.

5'-Nucleotidase↗