[Prenatal cytogenetic diagnosis of trisomy 21 using amniotic fluid cells].

Background: Trisomy 21 is the most frequent chromosomal disorder which is associated with advanced maternal age.

Objectives: The aim of our work was to examine the risk of trisomy 21 occurrence in a group of pregnant women subdued to prenatal cytogenetic examination.

Methods: The examined group consisted of 1128 pregnant women.

[Prenatal cytogenetic diagnosis in older pregnant women].

The paper deals with the genetic risk of advanced age of women assessed on the basis of prenatal cytogenetic analysis during the second trimester of gestation. The examined group comprised 614 pregnant women older than 35 years. The cells for chromosomal analysis were obtained by transabdominal amniocentesis during the 16th to 18th week of gestation.

Cytogenetic analysis of peripheral blood lymphocytes in workers occupationally exposed to polychlorinated biphenyls.

The ability of polychlorinated biphenyls (PCBs) to induce chromosome aberrations and sister chromatid exchanges (SCE) in peripheral lymphocytes was studied in a group of workers occupationally exposed to PCBs during the production of the Czechoslovak PCB products Delor 103 and Delor 106. The effect of PCB exposure was compared between an exposed group (N = 32, 3.25 +/- 0.

[Relation of the occurrence of chromosome aberrations in human peripheral lymphocytes to the cell cycle].

Experimental results confirmed that the best period of cultivation of human peripheral lymphocytes for chromosomal analyses in subjects exposed to mutagens and carcinogens is 44-48 hours when the dividing lymphocytes are in the first cellular cycle. With prolongation of the cultivation period of lymphocytes the values of chromosomal aberrations decline because in subsequent cellular cycles their number declines as a result of mitotic deaths of cells which contain unstable types of aberrations.

Changes in cellularity, CFU-S number and chromosome aberrations in bone marrow and blood of rats after neutron and continuous gamma irradiation.

Changes in the hematopoietic bone marrow of rats were observed after single wholebody neutron dose of 2 Gy and combined single neutron (2 Gy) and continuous gamma (6 Gy, daily dose rate of 0.5742 Gy) irradiation. Neutron irradiation significantly reduces the number of karyocytes in the bone marrow including CFU-S and induces the extensive cytogenetic damage.