Studies on the swelling of rat-liver mitochondria in relation to tumor incidence during feeding of aminoazo dyes

Résumé Dans des groupes de rats nourris à un régime contenant du 3-méthyl-p-diméthylaminoazobenzène, on constate, qu'il y a un accroissement soudain, à 4 semaines, de l'incidence de tumeurs hépatiques. Cette observation établit une correlation directe entre la cancérogenèse et le minimum des courbes de gonflement des microsomes et des mitochondries de foies de rats, nourris dans les mêmes conditions.     

Evolution of king crabs from hermit crab ancestors.

King crabs (Family Lithodidae) are among the world's largest arthropods, having a crab-like morphology and a strongly calcified exoskeleton. The hermit crabs, by contrast, have depended on gastropod shells for protection for over 150 million years. Shell-living has constrained the morphological evolution of hermit crabs by requiring a decalcified asymmetrical abdomen capable of coiling into gastropod shells and by preventing crabs from growing past the size of the largest available shells. Whereas reduction in shell-living and acquisition of a crab-like morphology (carcinization) has taken place independently in several hermit crab lineages, and most dramatically in king crabs, the rate at which this process has occurred was entirely unknown. We present molecular evidence that king crabs are not only descended from hermit crabs, but are nested within the hermit crab genus Pagurus. We estimate that loss of the shell-living habit and the complete carcinization of king crabs has taken between 13 and 25 million years.     

Antitumor effect of β-elemene in non-small-cell lung cancer cells is mediated via induction of cell cycle arrest and apoptotic cell death

-Elemene is a novel anticancer drug, which was extracted from the ginger plant. However, the mechanism of action of -elemene in non-small-cell lung cancer (NSCLC) remains unknown. Here we show that -elemene had differential inhibitory effects on cell growth between NSCLC cell lines and lung fibroblast and bronchial epithelial cell lines. In addition, -elemene was found to arrest NSCLC cells at G2-M phase, the arrest being accompanied by decreases in the levels of cyclin B1 and phospho-Cdc2 (Thr-161) and increases in the levels of p27^kip1 and phospho-Cdc2 (Tyr-15). Moreover, -elemene reduced the expression of Cdc25C, which dephosphorylates/activates Cdc2, but enhanced the expression of the checkpoint kinase, Chk2, which phosphorylates/ inactivates Cdc25C. These findings suggest that the effect of -elemene on G2-M arrest in NSCLC cells is mediated partly by a Chk2-dependent mechanism. We also demonstrate that -elemene triggered apoptosis in NSCLC cells. Our results clearly show that -elemene induced caspase-3, –7 and –9 activities, decreased Bcl-2 expression, caused cytochrome c release and increased the levels of cleaved caspase-9 and poly(ADP-ribose) polymerase in NSCLC cells. These data indicate that the effect of -elemene on lung cancer cell death may be through a mitochondrial release of the cytochrome c-mediated apoptotic pathway.Received 12 January 2005; accepted 5 February 2005     

Respiratory control in liver mitochondria of rats hosting the walker 256 carcinoma tumor.

The decrease in the respiratory control ratio of mitochondria is a first order process when these organelles are incubated in isotonic sucrose. Furthermore, the initial respiratory control ratios and the rates of loss in respiratory control in liver mitochondria from rats hosting the Walker 256 carcinoma are not significantly different form the same properties of mitochondria from untreated animals.     

Slow spontaneous signals from brain tissue culture

Resumen La exploratión con microelectrodos, de explantes telencefálicos de embrión de pollo, registra espontáneamente señales de dos tipos: lentas y rápidas, confirmando hallazgos similares previamente reportados con macroelectrodos. Observandose un patron en la distributión de las señales lentas, las cuales son originadas por la misma fuente en cada explante pudiendo ser esta, las células de glía o el producto de potensiales dendríticos.     

Analysis of a turbidimetric method for quantitatively estimating cell aggregation

Résumé Une technique a été établie pour estimer quantitativement l'aggrégation des cellules des tissus dissociés par une méthode turbidimétrique. Des fibroblastes de l'embryon de poulet ont été mis en rotation sur un absorbtiomètre. Pendant l'aggrégation des cellules vivantes, on observe une diminution de la densité optique de la suspension mésurée par un galvanomètre.