Modulation of the genotoxicity of bleomycin by amines through noncovalent DNA interactions and alteration of physiological conditions in yeast.

The effects of amines on the induction of mitotic gene conversion by bleomycin (BLM) were studied at the trp5 locus in Saccharomyces cerevisiae strain D7. BLM induces double-strand breaks in DNA and is a potent recombinagen in this assay. The polyamine spermidine causes concentration-dependent protection against the genotoxicity of BLM, reducing the convertant frequency by over 90% under the most protective conditions.

Somatic instability of the NF2 gene in schwannomatosis.

Context: Schwannomatosis is a newly described form of neurofibromatosis of unclear pathogenesis.

Patient And Methods: We studied the NF2 locus on chromosome 22 in 7 tumor specimens resected from a 36-year-old man with schwannomatosis of the right ulnar nerve.

Results: Unrelated truncating NF2 gene mutations were detected in 4 tumor specimens.