PubMed Health⌕ Search

Biomedical subjects

B Robaye

Publications and source records attributed to B Robaye.

41 records · Page 3Linked to original sources
PubMedDate not supplied

Apoptotic cell death analyzed at the molecular level by two-dimensional gel electrophoresis.

The pattern of protein expression and phosphorylation after an apoptotic stimulus has been studied in two systems. Bovine aortic endothelial cells were induced to undergo apoptotic cell death by a combination of a cytokine (tumor necrosis factor, TNF) and inhibitors of protein synthesis, like cycloheximide. Two-dimensional (2-DE) electrophoresis of proteins from such cells revealed specific proteolysis of distinct proteins, some at an early stage of apoptosis and some at a later stage. These proteins may have antiapoptotic properties. In rat IPC-81 promyelocytic leukemia cells, cAMP induced apoptosis. 2-DE of such cells pulse-labeled with [35S]methionine revealed two "novel" protein spots (of 30 kDa and 46 kDa, respectively), induced very rapidly by a posttranscriptional mechanism. It is proposed that "dysphosphorylation" may accompany apoptosis in general, since both endothelial cells treated with TNF/cycloheximide and IPC-81 cells treated with cAMP analog or the apoptosis-inducing phosphatase inhibitors okadaic acid or calyculin A all showed altered protein phosphorylation patterns, as revealed by 2-DE electrophoresis of proteins from cells prelabeled with 32Pi.

Animals↗
PubMedDate not supplied

Importance of cell kinetics rhythmicity for the control of cell proliferation and carcinogenesis in rat liver (review).

The circadian control of cell Proliferation and Differentiation has been studied principally in rat liver. The comparison between the differentiation by hepatic enzymes and the division by the cell cycle under various experimental conditions (postnatal maturation, regeneration after partial hepatectomy, adrenalectomy, corticosterone treatments etc.) leads to the following conclusions: Under physiological conditions, proliferation and differentiation activities present a mutually exclusive relationship with a specific circadian rhythm. For both functions, the circadian variation of corticosterone plays the role of synchronizer, each evening (peak) it induces the synthesis of tissue specific enzymes in G0 cells and simultaneously inhibits the DNA synthesis in cycling cells. The same parameters have been studied during the different stages of hepatocarcinogenesis induced by Diethylnitrosamine (DEN). After initiation alone, (DEN for 2 weeks) circadian control is unchanged and precancerous cells are not able to reach malignancy. Promotion (DEN for 6 weeks) consists of disturbing the circadian synchronization to liberate the selective growth of initiated precancerous cells. This proliferation advantage favours the accumulation of chromosomal aberrations including those implicated in malignant transformation: i.e. activation of oncogenes or inhibition of antioncogenes.

Animals↗