Molecular analysis of Lesch-Nyhan syndrome found in Japan

Molecular analysis of four unrelated patients with Lesch-Nyhan (L-N) syndrome was performed. All four cases had typical clinical features of L-N syndrome, and the activities of hypoxanthine-guanine phosphoribosyltransferase (HPRT) were absent. No structural gene abnormalities were found by Southern blot analysis in all cases, and a decrease of HPRT mRNA was not detected by dot blot analysis in two of the four cases. However, HPRT enzyme proteins were detected by Western blot analysis in all cases. Our results showed that the production of immunologically reactive but enzymatically inactive mutant HPRT protein was pathogenic for all four patients.

A new glucose-6-phosphate dehydrogenase variant (G6PD Tsukui) associated with congenital hemolytic anemia

A new glucose-6-phosphate dehydrogenase (G6PD) variant associated with chronic nonspherocytic hemolytic anemia was found in a 20-year-old Japanese male who showed mild hemolysis after an upper respiratory tract infection. The patient had been noted to have jaundice and reticulocytosis several times before this episode. The enzyme activity of the variant was 1.5% of normal. The enzymatic characteristics were slow anodal electrophoretic mobility, high Km G6P, normal Km NADP, decreased heat stability, and a normal pH optimum. From these results, the enzyme was considered to be a new class 1 variant and was designated G6PD Tsukui.

Elevated erythrocyte adenosine deaminase activity in a patient with primary acquired sideroblastic anemia

We report a case of primary acquired sideroblastic anemia (PASA) associated with elevated erythrocyte adenosine deaminase (ADA) activity. The patient was an 85-year-old Japanese male. Analysis of the peripheral blood revealed pancytopenia, and the bone marrow findings showed marked ringed sideroblasts and chromosomal deletion (46XY, 11q-). The erythrocyte ADA activity was 17 times higher than that of normal control, the leukocyte ADA activity was within the normal range, and the plasma ADA activity was 2 times higher than the normal mean. The adenine nucleotides in the patient's erythrocytes were within normal range. According to starch gel electrophoresis, ADA isozyme of the patient was ADA 1. Western blotting showed an increased amount of ADA protein in the patient's erythrocytes. Southern blotting revealed no gene amplification or large structural change. Dot blot analysis of the reticulocyte mRNA showed no increase in the amount of ADA mRNA in the patient's reticulocytes compared with those of reticulocyte-rich controls. We considered that the mechanism of elevated ADA activity in this acquired defect was similar to that found in hereditary hemolytic anemia associated with ADA overproduction.

Genotypic analysis using a Y-chromosome-specific probe following bone marrow transplantation

To monitor successful engraftment after bone marrow transplantation, we performed Southern hybridization analysis or dot blot analysis of DNA in a set of sex-mismatched cases using a Y-chromosome-specific DNA probe (pHY10). This method was extremely sensitive and rapid for checking which cells contain the Y-chromosome. Using this probe, analysis of cells from peripheral blood and bone marrow after transplantation demonstrated the usefulness of confirming engraftment of donor cells and of detecting mixed lymphohematopoietic chimerism.

Characterization of purine nucleoside phosphorylase in leukemia

Purine nucleoside phosphorylase (PNP) activity was determined in mononuclear cells from 49 patients with various types of leukemia. A low level of PNP activity was found in mononuclear cells from patients with acute myeloid and lymphoblastic leukemia and with chronic lymphocytic leukemia. Enzymatic and immunological studies on PNP from leukemic cells of these patients revealed no differences in Michaelis constant for inosine, thermostability, electrophoretic mobility, immunological reactivity, or specific activity between the PNP of leukemic cells and that of normal mononuclear cells. These results suggest that the decrease in PNP activity of leukemic cells is due to a decreased rate of enzyme synthesis. Thus, the abnormality of PNP activity might be due to an alteration in the regulatory mechanism of enzyme synthesis in the purine metabolism in the leukemic clone.

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.

A unique electrophoretic slow-moving glucose 6-phosphate dehydrogenase variant (G6PD Asahikawa) with a markedly acidic pH optimum

A new glucose 6-phosphate dehydrogenase (G6PD) variant associated with chronic nonspherocytic hemolytic anemia was discovered in Japan. The patient showed hemolytic crises after upper respiratory infections. The enzyme activity was about 3.8% of the normal. The partially purified enzyme revealed slow anodal electrophoretic mobility, high Km NADP, marked thermal-instability, and increased affinity for a substrate analogue (deamino-NADP). A particular characteristic of this enzyme was a biphasic pH curve with a greatly increased activity at low pH values. From these results, this variant was clearly different from hitherto observed G6PD variants, and was designated G6PD Asahikawa.

Gd(-) Gifu and Gd(-) Fukuoka. Two new variants of glucose-6-phosphate dehydrogenase found in Japan

Two new glucose-6-phosphate dehydrogenase (G6PD) variants were discovered in Japan. The first, found in a 9-year-old male, was associated with chronic hemolysis and hemolytic crises after upper respiratory infections. The enzyme activity of the variant was 2.9% of normal. The patient's G6PD showed an increased utilization of substrate analogue, deamino-NADP, and thermal instability. The second variant occurred in a 7-year-old male with drug-induced hemolysis. The main enzymatic characteristics were reduced enzyme activity, being 6.4% of normal, faster-than-normal anodal electrophoretic mobility, slightly high Michaelis constant for glucose-6-phosphate, thermal instability, and biphasic pH optima. Enzymatic properties of these variants allowed each to be distinguished from previously reported variants. The first variant was designated Gd(-)Gifu and the other, Gd(-)Fukuoka.

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.

[Two-dimensional echocardiographic observation of a rapidly growing floating left atrial ball thrombus: report of a case with mitral stenosis]

This report dealt with a rapidly growing ball thrombus floating in the left atrium in a case with mitral stenosis detected by serial two-dimensional echocardiography and confirmed at operation. A 45-year-old female was admitted to our hospital on January 7, 1982 because of dyspnea, orthopnea and fever. On admission she had typical auscultatory signs of mitral stenosis, and her chest roentgenogram revealed slight pulmonary venous congestion and marked left atrial enlargement. Laboratory findings including complete blood counts, coagulation studies and blood chemistry were normal except a positive CRP test. Two-dimensional echocardiography performed on January 8 revealed a tight mitral stenosis with the mitral orifice area of about 0.9 cm2, and a floating ball thrombus in the left atrium, which was 2.5 X 3 cm in size. Fuzzy echoes flowing slowly around the thrombus were also observed. Intravenous administration of heparin was started immediately. In the next morning (January 9), the two-dimensional echocardiography was reexamined, which revealed a markedly growing thrombus which became 4 X 4 cm in size. Several hours after the reexamination mitral valve replacement was performed. The removed thrombus was 5.5 X 7 cm in size and consisted of three laminated structures. This finding was consistent with the echocardiographic observations. Coagulation studies made just before operation showed increased coagulability. Increased stagnation of blood in the left atrium due to heart failure and a transient increase of blood cell aggregation and coagulability induced by preceding infection might be responsible for the genesis of such a thrombus.