Adenosine deaminase isoenzymes of the opossum Didelphis virginiana: initial chromatographic and kinetic studies.

Extracts of liver and spleen were used to isolate opossum adenosine deaminase isoenzymes (ADA1 and ADA2) and to determine their activities with adenosine and 2'-deoxyadenosine as substrates. Km values (microM) for adenosine and 2'-deoxyadenosine, respectively, as substrates for partially purified opossum liver adenosine deaminase isoenzymes were ADA1: 57 +/- 7 vs. 26 +/- 4 and ADA2: 285 +/- 25 vs.

2'-Deoxyadenosine metabolism in human and opossum Didelphis virginiana erythrocytes in vitro.

1. In erythrocytes of both species, deamination and phosphorylation of dADO was completely inhibited by 5 microM 2'deoxycoformycin and 10 microM 5-ITU respectively. 2.

The effect of enzyme replacement on red cell adenine deoxyribonucleotides in adenosine deaminase-deficient erythrocytes of the opossum, Didelphis virginiana.

1. Polyethyleneglycol-modified bovine adenosine deaminase was administered (10-20 U/kg/week) intramuscularly to two opossums for 15 weeks and changes in red cell adenine ribo- and deoxyribonucleotides quantitated by HPLC. 2.

Studies on the energy metabolism of opossum (Didelphis virginiana) erythrocytes: V. Utilization of hypoxanthine for the synthesis of adenine and guanine nucleotides in vitro.

High pressure liquid radiochromatography was used to test the ability of opossum erythrocytes to incorporate tracer amounts of [G-3H] hypoxanthine (Hy) into [3H] labelled triphosphates of adenine and guanine. In the presence of supraphysiologic (30 mM) phosphate which is optimal for PRPP synthesis, both ATP and GTP are extensively labelled. When physiologic (1 mM) medium phosphate is used, red cells incubated under an atmosphere of nitrogen accumulate [3H] ATP in a linear fashion suggesting ongoing PRPP synthesis in red cells whose hemoglobin is deoxygenated.

Clinical features and molecular analysis of the alpha thalassemia/mental retardation syndromes. I. Cases due to deletions involving chromosome band 16p13.3.

We describe eight patients who have alpha thalassemia which cannot be accounted for by the Mendelian inheritance of abnormal alpha globin genes. Apart from the hematologic abnormality, the other universal clinical finding is mild to moderate mental handicap; there is also a broad spectrum of associated dysmorphic features. Initial analysis of the alpha globin gene complex (which maps to chromosome band 16p13.

Studies on the energy metabolism of opossum (Didelphis virginiana) erythrocytes--VI. De novo purine nucleotide biosynthesis is limited to the final steps of the pathway in vitro.

1. High pressure liquid radiochromatography was used to show the incorporation of [14C] formate with Z-compounds into ATP and GTP in opossum erythrocytes. 2.

Studies on the energy metabolism of opossum Didelphis virginiana erythrocytes--IV. Red cells have low adenosine deaminase activity and high levels of deoxyadenosine nucleotides.

Alkaline extracts of adult opossum red cells were used to determine triphosphates of adenosine, deoxyadenosine and guanosine by anion exchange HPLC. Mean (nm/g Hg) ATP content of erythrocytes was 3713 and that of dATP 1913 (n = 12). Sonicates of red cells deaminated adenosine (ADO) at a rate of 1.

Studies on the energy metabolism of opossum Didelphis virginiana erythrocytes--III. Metabolic depletion with 2-deoxyglucose markedly accelerates methemoglobin reduction in opossum but not in human erythrocytes.

1. Glucose-depleted, nitrite-treated erythrocytes reduce ferriheme in vitro in an environment 100 mM to 2-deoxy-D-glucose at a rate of 2.4 microM/ml cells/hr (opossum) and 0.

Studies on the energy metabolism of opossum Didelphis virginiana erythrocytes--II. Comparative aspects of 2-deoxy-D-glucose catabolism in opossum and human red cells in vitro.

1. G-6-P, F-6-P, F-1, 6-P, DHAP and GA-3-P in opossum erythrocytes were found at levels above those reported in human red cells. 2.

Nuclear bridging of erythroblasts in acquired dyserythropoiesis: an early and transient preleukemic marker.

The clinical, hematologic, and histological characteristics of two patients who progressed from refractory anemia to acute leukemia are described. When first studied, nuclear bridging of erythroblasts, similar to that seen in congenital dyserythropoietic anemia type I and megakaryocytic dysplasia, were the only abnormalities. Within 6 years, both patients died, the first of acute nonlymphocytic leukemia, the second of erythroleukemia.

Unclassified type of congenital dyserythropoietic anaemia (CDA) with prominent peripheral erythroblastosis.

Two unrelated cases of congenital dyserythropoietic anaemia (CDA) are described. They show striking similarities which could not be attributed to one of the well-known types of CDA or any other congenital disease of the erythroid system. Both patients were followed for many years before and after splenectomy.

Studies on the energy metabolism of opossum (Didelphis Virginiana) erythrocytes. I. Utilization of carbohydrates and purine nucleosides.

Opossum erythrocytes filtered through cellulose columns were used to estimate their permeability to D-glucose and optimum inorganic phosphate requirement for D-glucose utilization at pH 7.4 and 8.1.

Comparative aspects of methemoglobin formation and reduction in opossum (Didelphis virginiana) and human erythrocytes.

Glucose-depleted, nitrite-treated opossum erythrocytes effectively reduce methemoglobin in an environment of physiological saline and added glucose does not accelerate the rate of reduction. In autologous plasma or 25 mM phosphate-buffered saline pH 7.4, added glucose significantly accelerates methemoglobin reduction in glucose-depleted, nitrite-treated opossum erythrocytes.

Hemoglobin H disease and mental retardation: a new syndrome or a remarkable coincidence?

Each of three families of northern European origin contains a mentally retarded son with hemoglobin H (Hb H) disease. One parent is a carrier of mild alpha-thalassemia and the other is normal, suggesting that this form of Hb H disease results from the interaction between an inherited defect of alpha-chain production and one member of the pair in chromosome 16 and a new mutation on the other. Restriction-enzyme analysis indicated that the new mutation was not the same in the other three patients, and demonstrated at least two hitherto undescribed lesions involving the alpha-globin gene cluster.

Acquired hemoglobin H in refractor sideroblastic anemia. A preleukemic marker.

Two patients with idiopathic refractory sideroblastic anemia (IRSA) were found to have acquired hemoglobin H. Both developed leukemic syndromes. Six other patients with IRSA had normal hemoglobin electrpohoretic patterns, and none has developed acute leukemia in up to five years.

Hemoglobins of the opossum (Didelphis marsupialis). II. Polymorphism; electrophoretic and chromatographic observations.

Eighty-five adult opossums (Didelphis marsupialis) were examined for variation of hemaglobin by means of electrophoresis and column chromatography. A single hemoglobin was found in 83 animals while two hemoglobins were observed in two animals. The results of the chromatography studies suggested that the polymorphism was due to primary sequence differences in the alpha chain.

Hemoglobins of the opossum (Didelphis virginiana Kerr). I. Developmental changes from yolk sac to definitive erythropoiesis.

In 5- to 7-da old opossum pouch young, hemoglobins were observed. The "primitive" species I, II, and IV were shown to be electrophoretically distinct from the adult hemoglobin III. Hemoglobin I was detectable until the 7th postnatal da.

Nonsecretory plasma cell dyscrasia followed by acute granulocytic leukemia 25 years after Thorotrast administration.

Twenty-three years after an injection of Thorotrast, profound depression of humoral and cellular immunity associated with extensive marrow plasmocytosis developed in a man aged 75 years. Twelve months of chemotherapy with L-phenylalanine mustard, resulted in hematologic remission. Radioautograph of his marrow showed signs of alpha-radiation; whole body counting revealed a significant thorium burden.

Hereditary persistence of fetal hemoglobin, beta thalassemia, and the hemoglobin delta-beta locus: further family data and genetic interpretations.

Three Negro kindreds with hereditary persistence of fetal hemoglobin (HPFH) alone and in combination with various other hemoglobin abnormalities including beta thalassemia are presented. Among 11 offspring of two women heterozygous for both HPFH and the delta chain mutation Hb B2, five inherited the HPFH gene and six inherited the Hb B2 gene. In another kindred, a man inferred to be heterozygous for both HPFH and Hb C had six children; three offsprivg obtained the Hb C gene and three the HPFH gene.