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Leukemia L1210 cells with acquired resistance to 1-methyl-1-nitrosourea (MNU) (L1210/MNU) and 1.3-bis(2-chloroethyl)-1-nitrosourea (BCNU) (L1210/BCNU) were developed from leukemia L1210 cells sensitive to these drugs (L1210/0). The modal chromosome number of leukemia L1210/MNU and L1210/BCNU cells increases from 40 (L1210/0) to 41. It was shown that in leukemia L1210/MNU cells the inhibition of DNA synthesis after MNU administration in a therapeutic dose (80 mg/kg) is lasted within 24 hours, while that in leukemia L1210/0 cell--within 96 hours. After administration of BCNU (20 mg/kg) inhibition of DNA synthesis in leukemia L1210/BCNU cells reached of 50% of control in comparison with practically complete inhibition of DNA synthesis in leukemia L1210/0 cells. Centrifugation on alkaline sucrose density gradients revealed no differences in the rate of sedimentation of leukemia L1210/0, L1210/MNU and L1210/BCNU cell lysates. After 1 hour treatment with MNU of mice bearing L1210/MNU and L1210/0 leukemia cells single-strand breaks in DNA were determined. After 4 hours these strand-breaks retained in leukemia L1210/0 cells, but were eliminated in leukemia L1210/MNU cells. Administration of BCNU to mice with leukemia L1210/0 and L1210/BCNU cells resulted in both cases in the production of DNA aggregates. There is no complete cross-resistance between MNU and BCNU which allows a substitution of these drugs providing for the increase in their therapeutic efficiency.
G V Kukushkina, and
N M Peretolchina, and
E A Minenkova, and
V N Verovskiĭ, and
Z P Sof'ina
January 1988,
Neoplasma,
G V Kukushkina, and
N M Peretolchina, and
E A Minenkova, and
V N Verovskiĭ, and
Z P Sof'ina
February 1986,
Biulleten' eksperimental'noi biologii i meditsiny,
G V Kukushkina, and
N M Peretolchina, and
E A Minenkova, and
V N Verovskiĭ, and
Z P Sof'ina
January 1992,
Cancer immunology, immunotherapy : CII,
G V Kukushkina, and
N M Peretolchina, and
E A Minenkova, and
V N Verovskiĭ, and
Z P Sof'ina
July 1977,
Cancer research,
G V Kukushkina, and
N M Peretolchina, and
E A Minenkova, and
V N Verovskiĭ, and
Z P Sof'ina
September 1984,
Cancer research,
G V Kukushkina, and
N M Peretolchina, and
E A Minenkova, and
V N Verovskiĭ, and
Z P Sof'ina
January 1980,
Leukemia research,
G V Kukushkina, and
N M Peretolchina, and
E A Minenkova, and
V N Verovskiĭ, and
Z P Sof'ina
May 1967,
Cancer research,
G V Kukushkina, and
N M Peretolchina, and
E A Minenkova, and
V N Verovskiĭ, and
Z P Sof'ina
October 1965,
Cancer chemotherapy reports,
G V Kukushkina, and
N M Peretolchina, and
E A Minenkova, and
V N Verovskiĭ, and
Z P Sof'ina
July 1965,
Applied microbiology,
G V Kukushkina, and
N M Peretolchina, and
E A Minenkova, and
V N Verovskiĭ, and
Z P Sof'ina
June 1983,
Gan,
