Environmental and Molecular Mutagenesis - Legacy Tobacco ...

134 1989 EMS Abstracts
Notes pH 6 .4 or pH 7 .2'with NaOH, no clastogenic activity was observed . Using F12 medium
supplemented with 34 mM NaHC03, or 30 mM HEPES as buffer, we observed metaphases
at doses up to 25 or 30 mM of these acids and no clastogenic activity at 20-25 mM
or below . A mixture of S9 (final 10X) and NaOH induced chromosomal aberrations at
initial pH of ca . 10 .8 . When the mixture was incubated at 37°C for 1 hr and then
neutralized with HC1 to pH 9 .3 or pH 7 .4 . it showed no clastogenic activity . The
above results show that these acids and base are non-clastogenic and thus the
pseud-positive reactions attributable to non-physiological pH conditions could be
precluded by either neutralization of the treatment medium or enhancement of the
buffering ability .
http://legacy.library.ucsf.edu/tid/clb93d00/pdf
386
HUMAN SOMATIC MUTATIONS AT THE AUTOSOMAL HLA-A LOCUS
A .A . Morley and D .R . Turner, Haematology Department, Flinders Medical Centre,
Adelaide, Australia .
Human lymphocytes mutated at the HLA-A locus were isolated by immunoselection
using monoclonal anti-HLA-A2 or -A3 antibody and complement followed by cloning in
micropslates . Mutant frequency in 21 normal individuals, with mean age 35, was 3 .0
x 10- and in 10 elderly individuals with mean age 78 it was significantly higher
at 7 .2 x 10-s . Analysis of the T-lymphocyte receptor gene in 98 mutants showed
that ~