Dominant negative isoform of the Ikaros gene in patients with adult B-cell acute lymphoblastic leukemia.

Gene targeting studies in mice have shown that the transcription factor Ikaros plays an essential role in lymphoid development and as a tumor suppressor in T cells, whereas the related gene Aiolos functions as a tumor suppressor in B cells. We analyzed the expression levels of the Ikaros gene family, Ikaros and Aiolos, in human bone marrow samples from patients with adult acute lymphoblastic leukemia [ALL (n = 46; B-cell ALL = 41; T-cell ALL = 5)]. Overexpression of the dominant negative isoform of Ikaros gene Ik-6 was observed in 14 of 41 B-cell ALL patients by reverse transcription-PCR, and the results were confirmed by sequencing analysis and immunoblotting. None of the other dominant negative isoforms of the Ikaros gene were detected by reverse transcription-PCR analysis. Southern blotting analysis with PstI digestion revealed that those patients with the dominant negative isoform Ik-6 might have small mutations in the Ikaros locus. We did not detect any overexpression of dominant negative isoforms of Aiolos in adult ALL patients. These results suggest that Ikaros plays a key role in human B-cell malignancies through the dominant negative isoform Ik-6.

Decreases in Ikaros activity correlate with blast crisis in patients with chronic myelogenous leukemia.

Gene targeting studies in mice have shown that the lack of Ikaros activity leads to T-cell hyperproliferation and T-cell neoplasia, establishing the Ikaros gene as a tumor suppressor gene in mice. This prompted us to investigate whether mutations in Ikaros play a role in human hematological malignancies. Reverse transcription-PCR was used to determine the relative expression levels of Ikaros isoforms in a panel of human leukemia/lymphoma cell lines and human bone marrow samples from patients with hematological malignancies. Among the cell lines examined, only BV-173, which was derived from a chronic myelogenous leukemia (CML) patient in lymphoid blast crisis, overexpressed the dominant-negative isoform, Ik-6. In 9 of 17 samples of patients in blast crisis of CML, Ikaros activity had been reduced either by drastically reducing mRNA expression (4 of 17) or by overexpressing the dominant-negative isoform Ik-6 (5 of 17). Significantly, expression of Ikaros isoforms seemed normal in chronic phase CML patients and patients with other hematological malignancies. In some cases, overexpression of the dominant-negative Ik-6 protein was confirmed by Western blot analysis, and Southern blot analysis indicated that decreases in Ikaros activity correlated with a mutation in the Ikaros locus. In summary, these findings suggest that a reduction of Ikaros activity may be an important step in the development of blast crisis in CML and provide further evidence that mutations that alter Ikaros expression may contribute to human hematological malignancies.

Automatic EEG interpretation: a new computer-assisted system for the automatic integrative interpretation of awake background EEG.

A new computer-assisted system for automatic interpretation of the awake electroencephalogram (EEG) was developed. First, all the items necessary for EEG interpretation were determined in accordance with the procedure that a qualified electroencephalographer (EEGer) goes through for the visual inspection of the background EEG activity, and then each item was defined quantitatively. For the automatic interpretation, specific EEG parameters were determined for each item so that they could fit the graded judgement of the item by the qualified EEGer as closely as possible. These specific EEG parameters were actually calculated from periodograms obtained from the time series of EEG records of 14 patients with various neurological diseases. The automatic EEG interpretation system thus established was applied to the EEG data of these 14 subjects and to 3 additional EEGs, and the results were compared with those obtained through the visual interpretation by the EEGer. This automatic EEG interpretation was found to be in good agreement with the visual interpretation by the EEGer in most EEG records. In contrast with the previous automatic analyses of EEG which were focussed on certain aspects of EEG such as the dominant rhythm, the present system is unique in its capability of providing an integrative interpretation of the spontaneous awake EEG by taking into account all its features except for paroxysmal abnormalities.

Phase I and pharmacokinetic study of SM-5887, a new anthracycline derivative.

SM-5887, a new totally synthetic anthracycline derivative was studied in a phase I setting. Twenty-nine evaluable courses of treatment were conducted in groups at doses increasing from 10 to 130 mg/m2. Myelosuppression was the dose-limiting toxicity and a MTD was 130 mg/m2. At 130 mg/m2 the median lowest white blood cell count was 0.7 x 10(3)/cmm (range: 0.3-1.8) and the median lowest granulocyte count was 0.1 x 10(3)/cmm (range: 0-0.7) and the median lowest platelet count was 57 x 10(3)/cmm (range: 4-176). Non-hematologic side effects were mild gastrointestinal symptoms and hair loss. The recommended dose and schedule for phase II setting is 100 mg/m2 every 3 weeks.

[Phase I study of SM-5887, a new anthracycline derivative].

SM-5887, a new totally synthetic anthracycline derivative, was studied in a phase I setting. Twenty-nine evaluable courses of treatment were conducted in groups at doses increasing from 10 to 130 mg/m2. At 130 mg/m2 the median lowest WBC count was 0.7 x 10(3)/mm3 (range 0.3-1.8) and the median lowest platelet count was 57 x 10(3)/mm3 (range 4-176). Nonhematological side effects were mild gastrointestinal symptoms and hair loss. The recommended dose and schedule for a phase II setting is 100 mg/m2 every 3 weeks.

[Phase II study of chlorambucil in patients with hematological malignancies].

Eight patients with various hematological malignancies were treated with chlorambucil, an analogue of nitrogen mustard. Five patients with CLL, 2 patients with malignant lymphoma, and one each with pseudolymphoma of the lung and primary macroglobulinemia were given 4-6 mg of chlorambucil per day for 1-2 weeks at 2-4 week intervals or a daily dose of 6 mg continuously. Two cases of CLL and one each of follicular lymphoma and pseudolymphoma achieved partial remission. Side effects included myelosuppression, especially leukopenia. Chlorambucil can be used orally without severe toxicity for longer periods and the major indication for this drug seems to be CLL and favorable type of malignant lymphoma.