Differential condensation of human chromosomes 9 and Y

Some differences were observed in the mitotic condensation of regions composing human chromosomes 9 and Y: regions 9p, 9h and Y nf are characterized by an intense condensation by the end of the spiralization interval studied (the length of the repair chromosome 3 varying from 5.4 to 2.9 mkm). At the same time, the condensation of regions 9q-h (region 9q without heterochromatic block) is slowing in the initial spiralization interval (the length of chromosome 3 varying from 16.6 to 5.5 mkm). The Yf-block of Y-chromosome is condensing faster than nf-region. The condensation parameters of Q-heterochromatic blocks are most variable while the euchromatic regions are most stable. The dynamics of 9h and of f-block condensation are independent within one karyotype. Based on the data obtained we doubt the correctness of studies on linear dimensions of the constitutive heterochromatin blocks for the evaluation of its quantity in the karyotype. A possible association of differential mitotic condensation with the chromosome segregation disturbances is discussed.     

Reproduction of chicken chromosomes at the end of the DNA synthesis period]

Reduplication of chicken chromosomes at the end of S-period in the cells of bone marrow was studied, using the method of prolonged labelling with 3H-thymidine and autoradiography. It is shown that during the last hour of the S-period the DNA synthesis in macrochromosomes ends primarily in the centromere region and the regions adjacent to it. Sex chromosomes (ZZ) of cocks accomplish the reproduction simultaneously.     

Pharmacokinetics of cephalexin and cephradine in surgical patients]

Pharmacokinetics of 2 oral cephalosporin antibiotics, i.e. cephalexin and cephradin in surgical patients with normal function of the liver and kidneys was studied. Both the drugs were satisfactorily absorbed into the blood reaching the maximum level in 1 hour. The antibiotics were determined in close concentrations in the blood serum of the patients during 5 hours of the observation. No differences in the time of a two-fold decrease in the antibiotic serum level and the value of the area limited by the antibiotic blood level were found. Cephalexin and cephradin were excreted with the urine in equal amounts.