Chromatin staining characteristic

Uncultured cells have also been used to a limited extent for fetal sex determination. This Is possible because the cells can be appropriately stained and examined for the presence of sex chromatin, characteristic of female cells, and for the fluorescent Y-body, characteristic of male cells (33,34). However, these cytologic techniques are not completely reliable, and It Is still desirable to determine fetal sex by direct chromosome analysis (35). 

Cells were cultured in a humidified ahnospheric incubator at 37°C in 5% CO2. Human promyelocytic leukemia cell line (HL-60) was cultured in RPMI 1640 supplemented with 13% heat-inactivated fetal bovine serum and SO U/mL penicillin-streptomycin. To induced myeloid differentiation, cells were seeded at a density of S IO cells/mL and were cultivated for five days in RPMI 1640 containing 1.24% DMSO. TTie characteristics of mature cells were determined by smaller cell size, decreased nucleoli-to-cytoplasm ratio and pyknotic changes in nuclear chromatin. Cell numbers were counted using a hemocytometer, and cell viability was >98% as evidenced by trypan blue staining. 

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