ABSTRACT
A total of 960 complementary DNA (cDNA) clones from an HL60 cell cDNA library were screened to discover genes that were differentially expressed in HL60 cells exposed to 60 Hz square-wave magnetic fields (MFs) compared to sham-exposed cells. Square-wave fields are rich in odd harmonic frequency content. We used a two-gel cDNA library screening method (BIGEL) to identify treatment-induced alterations in gene expression. Four cDNA clones were tentatively identified as differentially expressed after exposure to square-wave MFs at 2 mT for 24 h. BIGEL-identified genes (GenBank accession number) corresponding to these clones were: TI227H (D50525), EST Homo sapiens partial cDNA (Z17814), human ribosomal protein S13 (L01124), and AICAR transformylase mRNAs (D82348). The differences in mRNA levels were not confirmed in test compared to experimental cells by Northern analysis. In other experiments, we used concurrent exposure to 60 Hz sine- or square-wave MFs (0 or 2 mT, duration of 3 or 24 h, no postexposure delay). In addition to the four BIGEL genes, we also investigated MYC, HSP70, RAN and SOD1. In the case of MYC and HSP70, square-wave MFs appeared to exhibit more marked alterations when compared to sinusoidal waveforms, but the overall results indicated no effect of possible differential magnetic-field-induced expression of all eight genes. In contrast, alterations of mRNA levels were observed for seven genes after exposure to X irradiation, hyperthermia and TPA. These results are contrary to previously proposed similarities between the action of these agents and MF effects on gene transcription.
Subject(s)
Electromagnetic Fields/adverse effects , Gene Expression Profiling , Gene Expression/radiation effects , RNA, Messenger/metabolism , Blotting, Northern , Clone Cells , Expressed Sequence Tags , Gene Expression/genetics , HL-60 Cells , HSP70 Heat-Shock Proteins/biosynthesis , HSP70 Heat-Shock Proteins/genetics , Hot Temperature/adverse effects , Humans , Hydroxymethyl and Formyl Transferases/biosynthesis , Hydroxymethyl and Formyl Transferases/genetics , Phosphoribosylaminoimidazolecarboxamide Formyltransferase , Proto-Oncogene Proteins c-myc/biosynthesis , Proto-Oncogene Proteins c-myc/genetics , Ribosomal Proteins/biosynthesis , Ribosomal Proteins/genetics , Superoxide Dismutase/biosynthesis , Superoxide Dismutase/genetics , Superoxide Dismutase-1 , Tetradecanoylphorbol Acetate/pharmacology , X-Rays , ran GTP-Binding Protein/biosynthesis , ran GTP-Binding Protein/geneticsABSTRACT
Posttransplant lymphoproliferative disorder (PTLD) is a common and life-threatening complication of immunosuppression used to prevent rejection of solid organ and bone marrow transplants. There is no standardized treatment algorithm, but numerous management strategies are available. We describe a patient who developed a solitary lymphoproliferative lesion in the porta hepatis 9 months after orthotopic liver transplant. Following reduction in immunosuppression with no response, she was treated with involved field radiotherapy utilizing CT-based treatment planning. A partial radiographic response was obtained, and she has not developed disease in the engrafted liver or systemically. Based on the present case report, involved field radiotherapy seems to be a reasonable treatment option for patients with localized PTLD. Int. J. Cancer (Radiat. Oncol. Invest.) 90:104-109, 2000.
