Visualization of DNA segments, interacting with reactive oligonucleotide derivatives in interphase nuclei and metaphase chromosomes

Reaction of (pdT)16 derivatives, bearing 4-(N-2-chloroethyl-N-methylamino)benzylphosphamide group on its 5' end and biotin on its 3' end with DNA in interphase nuclei and metaphase chromosomes has been investigated by fluorescence and electron microscopy. The result obtained evidence that in interphase nuclei DNA in active chromatin (nucleolus) is the most available for specific modification. In metaphase chromosomes the modified DNA regions are situated on the surface of chromosome.     

Quantitative characteristics of the multiplication of muscle cells in the course of postnatal cardiogenesis in mice

Changes in the absolute number of muscle cells and nuclei in the ventricle during the 1st year of postnatal life were followed in males of the CC57BR mice. The counts were carried out in the cell suspension obtained from the fixed cardiac muscle by means of alkaline dissociation. The number of muscle cells and nuclei reliably increased during the 1st month of life and ceased to increase when the maturity was attained (2-3 months). The number of muscle cells increased twice and that of muscle nuclei almost 4 times. A comparative estimate was made of the role of proliferation and growth of muscle cells in the increase of ventricle weight with the age. The importance of individual variation of the number of muscle cells and nuclei during early postnatal ontogenesis for the study of the myocardium adaptive growth is discussed.