Nishio A

Inversion of chromosome 3 in a case of chronic myelogenous leukemia with abnormal thrombopoiesis

A patient with chronic myelogenous leukemia (CML) associated with a remarkable increase of micromegakaryocytes in bone marrow was revealed to have an abnormality of a long arm of chromosome #3, i.e., inv(3)(q21q26), in addition to a complex Ph translocation: t(9;22;15)(q34;q11;q22). Although several cases of acute leukemia with inv(3)(q21q26) and abnormal megakaryocytes have been reported, this is the first case in which the association of inv(3)(q21q26) with a megakaryocytic abnormality was observed in a patient with CML. Our findings suggest that this structural rearrangement may be more specifically associated with abnormal thrombopoiesis than are other structural anomalies of 3q.

Inhibition of DNA synthesis by chromium compounds

Cr(VI) irreversibly inhibited DNA synthesis in cultured mouse L cells to 50% of controls at 10 microM; 3.3 mM Cr(III) did not. At 0.3 mM, Cr(III) and Cr(VI) inhibited DNA synthesis in permeabilized L cells to 50% of control values. Cr(III) was a stronger inhibitor of DNA synthesis in the DNA-Escherichia coli DNA polymerase I system than was Cr(VI). The inhibitory effect of Cr(VI) depended on the ratio of Cr/DNA and Cr/enzyme; on the other hand, the increase in the concentration of DNA polymerase did not affect the inhibition of Cr(III), Cr(III), below the inhibitory concentration, produced an increase in the incorporation of [3H]dTMP into DNA; this was not observed with Cr(VI).

Translocation between chromosomes 8q24 and 14q11 in T-cell acute lymphoblastic leukemia.

Cytogenetic study was performed on a patient with T-cell acute lymphoblastic leukemia (T-ALL). It revealed a chromosomal translocation between chromosome bands 8q24 and 14q11. 8q24 is known to encode the oncogene c-myc, while 14q11 encodes the genes for T-cell receptor-alpha (TCR-alpha) and T-cell receptor-delta (TCR-delta). Therefore, this chromosomal translocation t(8;14) (q24;q11) seemed to be unique and specific to T-cell malignancy.

Translocations t(15;17) and t(9;14)(q34;q22) in a case of acute promyelocytic leukemia with increased number of basophils

A patient with a variant form of acute promyelocytic leukemia (M3 variant) associated with an increased number of basophils was found to present a reciprocal translocation, t(9;14)(q34;q22) in addition to t(15;17)(q22;q12). Although several cases of acute nonlymphocytic leukemia with increased bone marrow and peripheral blood basophils have been reported, this is the first case in which both the t(9;14) and basophilia were observed in a patient with M3. Our findings support the hypothesis that 9q34 may be associated with the chromosomal location of genes regulating the production and maturation of basophils.

Giant Neutrophils Derived from Tetraploid Leukemic Clone in an Acute Myeloblastic Leukemia: Cytofluorometric Study

Near-tetraploid chromosomes were observed in a patient with acute myeloblastic leukemia with maturation (M2 in FAB classification). Large and morphologically bizarre leukemic cells and giant neutrophils in each maturation stage were observed in both peripheral blood and bone marrow. Cytogenetic studies revealed that the main stem line was 93; XXYY, +9, and DNA cytofluorometry showed that these large leukemic cells and giant neutrophils had 4C DNA content. These findings strongly suggested that these giant neutrophils were derived from leukemic clone with tetraploidy.