[Characteristics of the cis- and trans-positions of chromatids of human acrocentric chromosomes in extreme old age]. / Kharakteristika tsis- i trans-polozhenii assotsiiruiushchikh khromatid akrotsentricheskikh khromosom cheloveka v glubokoi starosti.

Cis- and trans-positions of chromatid associations of human acrocentric chromosomes were examined at extreme old age. Lymphocyte cultures were prepared by the usual method, from peripheral blood of 9 subjects aged 80-90 years (analysis of 179 metaphases) and 7 subjects aged 20-48 years (analysis of 124 metaphases). The functional difference between stalks of the sister chromatids was found. In the subjects at the age 80-90 years satellite stalks of chromatids-1 (in all DNA strands thymidine was substituted by 5-BrdU) of the D chromosome in cis-position are included into associations with lower frequency, as compared with the satellite stalks of chromatids-2 (thymidine+ is only substituted by 5-BrdU in a half DNA strands of the chromosome). This apparently reflects variability of regulation of functional activity of satellite stalks of sister chromatids.

On errors related to the use of expert estimates.

The use of expert estimates has become a normal procedure for many applied problems, usually reduced to testing statistical hypotheses. A typical example is the problem of medical diagnostics, when experts are asked, for instance, to estimate the probability of appearance of different symptoms of different diseases. This paper treats the problem of the influence of the accuracy of expert estimates on the properties of the statistical tests used, that is, changes of their critical levels and powers are considered.