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Biomedical subjects

A Kuramoto

Publications and source records attributed to A Kuramoto.

At least 253 records · Page 14Linked to original sources

In vivo and in vitro activity of neutrophil alkaline phosphatase in acute myelocytic leukemia with 8;21 translocation.

Cytogenetic studies were made on 160 patients with acute nonlymphocytic leukemia (ANLL) between 1963 and 1979, of whom 115 had acute myelocytic leukemia with 67 patients showing aneuploidy (58.3%). Among these, 24 patients were found to have similar chromosome alterations that appeared to involve specifically chromosomes 8 and 21. Banding studies on at least 7 of these patients confirmed the presence of a translocation between these two chromosomes. Of 160 ANLL patients, 142 were scored for neutrophil alkaline phosphatase (neutrophil AP) at the time of diagnosis. Fifty-nine patients showed a low neutrophil AP score, 42 a normal value, and 41 a high value. All patients with 8;21 (or C/G) translocation had a low neutrophil AP score and leukemic cells with maturation (M2 of FAB classification) in the bone marrow. In vitro liquid culture for 2 wk of 8;21 translocated leukemic cells revealed no increase of neutrophil AP activity nor increase of mature granulocytes, whereas 9;22 translocated chronic myelocytic leukemia cells with a low neutrophil AP score did so. Neutrophil AP score at the time of diagnosis in acute myelocytic leukemia is very useful for detecting 8;21 translocation AML and for studying the pathophysiology and genetic alterations of the characteristic subgroup of AML with 8'21 translocation.

Adolescent↗

Chromosome aberrations in B lymphocytes of atomic bomb survivors.

Although chromosome aberrations in T lymphocytes and bone marrow cells have been reported in atomic bomb survivors, the presence of chromosome abnormalities has not been demonstrated in B lymphocytes because of the technical difficulties involved in B-lymphocyte separation. A method for detecting chromosome aberrations in B lymphocytes was established by "stimulation" of B lymphocytes with Epstein-Barr virus (EBV) instead of "separation" of B lymphocytes by rosette formation. The EBV-stimulated lymphocytes were isolated as single colonies in soft agar and transferred to liquid culture for further cell growth. The EBV-stimulated B lymphocytes of two heavily exposed survivors showed 50% and 12.5% chromosome abnormalities 30 yr after exposure to the effects of the atomic bomb. The former patient seemed to have a karyotypically abnormal clone of B lymphocytes in vivo. The method used in this study and the evidence of chromosome aberrations in B lymphocytes for long periods after radiation exposure will be useful and important in elucidating the malignant processes of acute lymphocytic leukemia, B-cell lymphoma, and multiple myeloma among high-risk groups having a history of accidental or therapeutic exposure to radiation or radiomimetic drugs.

Adolescent↗

Ultrastructural studies on the surface coat of human platelet aggregated by polylysine and dextran.

Positively charged macromolecule, polylysine (mol. wt. 15,000; 23,000; 180,000) could induce the platelet aggregation in low concentration but high concentration was required in the case of neutral macromolecule, dextran (mol. wt. 40,000; 250,000; 2,000,000). The larger molecules of polylysine and dextran were more effective in inducing platelet aggregation. In the dextran-induced aggregation, positively charged Thorotrast particles on the cell surface did not decrease significantly. On the other hand, the surface membranes of platelets aggregated by polylysine were essentially devoid of bound particles. Heparin inhibited the polylysine-induced platelet aggregation but not the dextran-induced aggregation. These findings suggested that polylysine induced aggregation more effectively than dextran by reducing the negative surface charge and giving stronger adsorption force on cell surface. In platelet-rich plasma, polylysine elicited the release reaction of 14C-serotonin but dextran did not. Possible mechanism by which polylysine could elicit the release reaction is the formation of more tightly packed platelet aggregate than that by dextran in the presence of the low calcium ion concentration in citrated platelet-rich plasma. Average distance between plasma membranes of aggregated platelets, however, did not vary with the degrees of polymerization of these macromolecules.

Adenosine↗