Ultrastructural study of apoptotic U7 cells treated with different pro‐apoptotic substances

Abstract

Human monocytic leukemia U937 cells readily undergo apoptosis when exposed to various stimuli, including inhibition of protein synthesis, oxidative stress, antitumoral agents, etc. The sequential, step-by-step morphological changes in U937 cells that occur during the apoptotic program are largely determined by the activation of a specific class of proteases, the caspases. The action of these proteases were followed at the ultrastructural level. From our observations 1) no unique morphological feature exists during apoptosis, even in the same cell type; 2) the extent of the morphological modifications are inducer- and dose-dependent; 3) double or triple treatments amplify the morphological modifications with a single inducer, but not the rate of apoptosis; and 4) in the case of double treatment the second inducer has to have a cytoplasmatic target because damage to the cytoplasm occurs before nuclear modifications become visible. These data should facilitate a more objective evaluation of apoptosis in conditions where antiproliferative drugs, like antiblastic or immunosuppressive molecules, are used to monitor the efficiency of treatment.

Evaluation and Prevention of Changes in Oral Cavity Through Cytotoxic Effect of the Chemical Components from Dental Materials

“…The biological material used in the in vitro test experiments of the cytotoxic impact of the eluates was represented by normal, non-contaminated kidney cell cultures (obtained from the monkey kidneys of Cercopithecus aethiops), maintained in 25 cm 2 plates. These plates contain DMEM growth medium (Dulbeco's Modified Essential Medium, Biochrom AG, Germany) supplemented with 2% fetal bovine serum, 100 µg/mL streptomycin (Biochrom AG, Germany), 100 IU/mL penicillin (Biochrom AG, Germany) and 50 µg/mL amphotericin B (Biochrom AG, Germany), being placed in an incubator with a humidified atmosphere, 5% CO 2 , and a temperature of 370 0 C [1][2][3]. When the cell cultures reached the monolayer stage, achieved by the confluence of the RM cells, they were detached from the lower solid substrate of the plate using a 0.25% trypsin solution and 0.02% EDTA (ethylene diamine tetra acetic acid, Biochrom AG, Germany), then centrifuged at 1800 rpm for 2 min and suspended one more in normal medium.…”