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Biomedical subjects

S Miwa

Publications and source records attributed to S Miwa.

At least 271 records · Page 15Linked to original sources
PubMed1986

Lesch-Nyhan syndrome in Japan.

An epidemiological survey of Lesch-Nyhan (L-N) syndrome in Japan was carried out. In the first survey, questionnaires were mailed to the pediatric departments of the university hospitals, homes for mentally retarded children, and city and county medical associations. This study disclosed 41 patients with L-N syndrome and 48 with suspected L-N syndrome. In the second survey, questionnaires were mailed to the institutes that reported cases or suspected cases of L-N syndrome. In 29 of these cases, hypoxanthine-guanine phosphoribosyltransferase (HPRT) activity in the patients' erythrocytes was measured. Three cases were confirmed to be L-N syndrome in this study. Among the other confirmed cases, the activities of HPRT had already been determined in 23 cases. In addition to these cases, 10 cases have been reported in the literature, and 16 cases were considered to be with L-N syndrome from their typical clinical features without any determination of HPRT activity.

Adolescent↗
PubMed1985

Establishment and characterization of human myelomonocytic (TYS) and histiocytic (TYH) cell lines.

Two human hematopoietic cell lines (TYS and TYH) with monocytic characteristics were derived from the peripheral blood of a patient with acute myelomonocytic leukemia and of another with a follicular large-cell type of malignant lymphoma. The TYS cells, derived from the leukemia patient, revealed a monocytic appearance with microvilli at one side and had many granules and vacuoles. They showed strongly positive reactions with alpha-NBE, NASDAE, and AcP, and were reactive with monoclonal antibodies such as OKlal, 12 and Bl. The TYS cells, which phagocytized carbon particles and antibody-coated SRBC but not latex particles, released lysosomal enzymes and tumoricidal factor into the supernatant. The TYH cells, derived from the malignant lymphoma patient, had abundant cytoplasm and pseudopods detectable by electron microscopy with a monocytoid appearance and virus-like particles in the cytoplasm. They showed strongly positive reactions with alpha-NBE, NASDAE and beta-Gase, but no reactivity with monoclonal antibodies or with surface markers except Fc gamma-R. TYH cells phagocytized latex particles very well. Two different human monocyte-histiocyte lineages were thus established. During culture, the TYS and TYH cells maintained their characteristics over 28 and 16 months of passage, respectively.

Animals↗
PubMed1985

6R-L-erythro-5,6,7,8-tetrahydrobiopterin as a regulator of dopamine and serotonin biosynthesis in the rat brain.

6R-L-Erythro-tetrahydrobiopterin (6R-BH4), the natural isomer of tetrahydrobiopterin, was synthesized from 7,8-dihydrobiopterin using dihydrofolate reductase. The effects of intracerebroventricular injection of 6R-BH4 on the biosyntheses of neurotransmitter monoamines in the rat brain were investigated by measuring accumulation of 3,4-dihydroxyphenylalanine (DOPA) and 5-hydroxytryptophan (5-HTP) after the inhibition of aromatic L-amino acid decarboxylase by NSD 1015 and the contents of metabolites of dopamine (DA) and 5-hydroxytryptamine (5-HT). The formation of DOPA and 5-HTP increased after the injection, reached a maximum level at about 1 h, then leveled off and reached a plateau over 2 h up to 8 h. The formation of DOPA and 5-HTP increased dose-dependently in the whole brain after the injection of 6R-BH4, and reached a plateau when the dose was more than 300 micrograms/rat. The enhancement was 100 and 70% for DOPA and 5-HTP, respectively. The formation of DOPA and 5-HTP increased in four brain regions, but the degree of stimulation was different among the brain regions. The contents of DA and 5-HT metabolites increased after the injection of 6R-BH4 in all brain regions tested, especially in the diencephalon and brain stem. The contents of DA and 5-HT increased slightly after the injection of 6R-BH4. These results suggest that 6R-BH4 concentration may be submaximal within DA and 5-HT neurons, and that an increase in 6R-BH4 in the brain enhances the biosyntheses of DA and 5-HT.

Animals↗
PubMed1985

Adenosine deaminase (ADA) in leukemia: clinical value of plasma ADA activity and characterization of leukemic cell ADA.

Adenosine deaminase (ADA) activity was measured in plasma, erythrocytes, and mononuclear cells from 18 patients with acute and chronic leukemia. High levels of ADA activities were found in plasma, erythrocytes, and mononuclear cells from patients with acute leukemia, especially acute lymphoblastic leukemia, and blastic crisis of chronic myeloid leukemia. Serial determination of plasma ADA activities was done in 9 patients with acute leukemia. All patients untreated or in relapse had an elevation of plasma ADA activity, which decreased to normal or subnormal levels during complete remission. On starch gel electrophoresis, plasma ADA in leukemic patients separated into two bands. The major band showed a mobility identical to that of normal red cells and mononuclear cells, and the minor band corresponded to that of normal plasma ADA. Enzymatic and immunological studies were performed on ADA from leukemic cells of acute myeloid and lymphoblastic leukemia. There were no differences in Michaelis constant for adenosine, thermostability, electrophoretic mobility, immunological reactivity, and specific activity between ADA of leukemic cells and normal mononuclear cells. These results strongly suggest that the increased ADA activity in leukemic cells is caused by an increased synthesis of a structurally normal enzyme and that increased plasma ADA activity in leukemic patients reflects an increment of leukemic cells in bone marrow. Therefore, serial determination of plasma ADA activities seems to provide a good indicator of the total mass of leukemic cells in bone marrow.

Acute Disease↗
PubMed1985

Molecular aspects of erythroenzymopathies associated with hereditary hemolytic anemia.

Since the discovery of glucose 6-phosphate dehydrogenase (G6PD) and of pyruvate kinase deficiencies, erythroenzymopathies associated with hereditary hemolytic anemia have been extensively investigated. Kinetic and electrophoretic studies have shown that most, if not all, erythroenzymopathies are caused by the production of a mutant enzyme. Except for a few enzymes that are abundant in blood and tissues, it is difficult to obtain enough sample to study the functional and structural abnormalities of mutant enzymes associated with genetic disorders in man. The primary structures of only two normal red cell enzymes which can cause hereditary hemolytic anemia, phosphoglycerate kinase (PGK) and adenylate kinase, have been determined. Single amino acid substitutions of PGK variants have been found, and the identification of the exact molecular abnormalities of such variants has helped us to understand the accompanying functional abnormality. Gene cloning makes possible the identification of the DNA sequence that codes for enzyme proteins. Recently, human complementary DNA (cDNA) for aldolase, PGK, G6PD, and adenosine deaminase (ADA) have been isolated, and the nucleotide sequences for PGK and ADA determined. In the near future, human cDNA sequencing should permit identification of the gene alteration that gives rise to the mutant enzymes.

5'-Nucleotidase↗
PubMed1985

Thyroid hormone induces metamorphosis of flounder larvae.

The role of thyroid hormone in flounder metamorphosis was studied by use of thyroxine and the antithyroidal agent, thiourea (TU). T4 stimulated metamorphosis of pelagic larvae, producing miniatures of naturally metamorphosed benthic juveniles. In contrast, TU induced metamorphic stasis, resulting in giant pelagic larvae. These results indicate that the thyroid plays a role in flounder metamorphosis comparable to its well-known developmental role in amphibian metamorphosis.

Animals↗
PubMed1985

Effects of L-thyroxine and ovine growth hormone on smoltification of amago salmon (Oncorhynchus rhodurus).

In a study of the hormonal control of salmon smoltification, L-thyroxine (T4; 200 ppm in diet), ovine growth hormone (oGH; 2 micrograms/g intramuscular injection weekly), or a combination of these hormones was administered to underyearling amago salmon parr for 72 days. Administration of both T4 + oGH remarkably stimulated growth of the fish. All hormone treatments caused body silvering of the fish. The body silvering was the greatest in the group treated with T4 + oGH. Both T4 + oGH and oGH increased survival rate of the fish in 32% seawater, and kept plasma osmolarity and plasma sodium concentration lower than those of T4-treated and control groups in 27% seawater. Significant elevation of gill Na+, K+-ATPase activity was found in T4 + oGH-treated fish. On the other hand, T4 by itself did not affect the seawater tolerance of the fish. These findings suggest that GH or synergistic action of GH and T4 plays an important role in seawater adaptation during smoltification of amago salmon.

Adaptation, Physiological↗
PubMed1985

Effect of mammalian growth hormone on amino nitrogen mobilization in the eel.

Hypophysectomy decreased plasma amino nitrogen (PAN) levels of Japanese eels. In contrast, administration of bovine or ovine growth hormone (GH; 2 micrograms/g) produced a delayed increase in PAN levels of both intact and hypophysectomized eels 48 hr after GH injection. The minimum dose of GH required to elevate PAN levels was found to be 0.1-1 micrograms/g body wt. The fact that GH treatment also increased PAN of hepatectomized eels indicates that the increased PAN was at least partly caused by the increased mobilization of amino nitrogen from body protein. GH also increased plasma free fatty acid content of intact and hypophysectomized eels 48 hr after GH injection in one experiment of the present study, but this effect was not reproducible in other experiments. No effect of GH administration was observed either in plasma glucose and lipid of intact and hypophysectomized eels 48 hr after the injection.

Amines↗
PubMed1985

Suppression of mixed lymphocyte reaction by cells of human first trimester pregnancy endometrium.

In order to identify an immunological role for decidual tissue in pregnancy we have prepared single cell suspensions from the tissues of normal pregnant women and examined the effects of these cells on one-way mixed-lymphocyte reactions (MLR). The separated cells were heterogeneous, containing classical decidual cells, glandular epithelial cells, granular endometrial cells, macrophages and small lymphoid cells. [3H]Thymidine incorporation at day 6 of the MLR was suppressed by addition of the cells at the initiation of the cultures and the degree of suppression was inversely correlated to the gestational age of the decidual tissue, apparently through inhibition of the antigen recognition phase of the MLR. These findings support the view that the cells of the human first trimester pregnancy endometrium may play an important role in protecting the feto-placental unit from rejection, at least in the early phase of pregnancy.

Antigens, Surface↗
PubMed1985

Three kinds of foamy cells in the spleen: comparative histochemical and ultrastructural studies.

By light and electron microscopy, we observed foamy cells in the spleens from a patient with hemolytic anemia due to red cell adenosine deaminase (ADA) overproduction, a patient with rheumatoid arthritis (RA) treated with gold, and patients with idiopathic thrombocytopenic purpura (ITP). The foamy cells associated with red cell ADA overproduction were essentially similar to Gaucher-like cells described in patients with thalassemia, and it was suggested that the accelerated destruction of red cells was one of the factors responsible for the development of foamy cells. Foamy cells in ITP and RA were closely associated with an increased destruction of platelets in the spleen. Morphologic transitions between phagocytosed platelets and myelin-like materials were traced in these disorders. In RA, however, foamy cells were heterogeneous from an ultrastructural standpoint, with different cytoplasmic inclusions. In addition to myelin-like materials, dense bodies, vacuoles with flocculent materials, and gold were noted in most of foamy cells. As gold compounds are known to inhibit lysosomal enzymes, we surmise that an acquired disturbance in lysosomal digestion is partially responsible for the accumulation of intermediate metabolites. In the pathogenesis of foamy cells associated with blood cell dyscrasia, the accelerated destruction of blood cells and/or acquired disorders in catabolic pathways within the macrophages are suggested to be the underlying mechanism of an intralysosomal accumulation of incompletely degraded cellular debris.

Adenosine Deaminase↗
PubMed1985

A new unstable, high oxygen affinity hemoglobin: Hb Nagoya or beta 97 (FG4) His----Pro.

An unstable hemoglobin was detected by isopropanol and heat precipitation tests in a 49-year-old Japanese man suffering from acute exacerbation of a chronic hemolytic disorder which was apparently triggered by infection of cholelithiasis. One of his two sons carried the same abnormal hemoglobin, and was jaundiced, but otherwise healthy, without anemia. The abnormal hemoglobin focused at a slightly more anodic position than Hb A in thin layer polyacrylamide gel electrofocusing. The abnormal beta chain emerged after normal beta chain in reverse phase high performance liquid chromatography of the hemolysate. It comprised 16.7% and 25.5% of the total beta chain in the propositus and his son, respectively. The partially heme-depleted abnormal beta subunit was precipitated with p-chloromercuribenzoic acid, and the abnormal beta chain was isolated by urea CM-cellulose column chromatography. Structural analysis demonstrated substitution of proline for histidine at position 97 (FG4) in the beta chain. The abnormal hemoglobin was purified by ion-exchange column chromatography. It showed a hyperbolic oxygen equilibrium curve indicating a high oxygen affinity and the absence of cooperative intersubunit interaction. Subunit dissociation seemed to be slightly enhanced. The variant was markedly susceptible to oxidation and rapidly lost heme upon oxidation.

Amino Acid Sequence↗
PubMed1985

Hb F-Tokyo or alpha 2G gamma 2 34(B16)Val----Ile, a silent gamma chain variant detected by reverse phase high performance liquid chromatography.

Hb F-Tokyo with a Valine----Isoleucine replacement at position gamma 34(B16) is a G gamma chain variant which was discovered by reverse phase chromatography as this method permitted the nearly complete separation of the three types of gamma chain. The chemical characterization was greatly facilitated by the use of a larger, preparative, HPLC column which allowed the isolation of sufficient quantities of the different gamma chains.

Amino Acids↗