Effect of varying hypoxia reoxygenation times on autophagy of cardiomyocytes

Abstract Purpose: To investigate the impact of different hypoxia reoxygenation (HR) times on autophagy of rat cardiomyocytes (H9C2). Methods: Rat cardiomyocytes were randomly divided into normal control group (group A), hypoxia group (group B), 2 h HR group (group C), 12 h HR group (group D), and 24 h HR group (group E). LC3 II/LC3 I was determined via western blotting, and cell viabilities of cardiomyocytes were measured using methyl thiazolyl tetrazolium (MTT) assay. Results: Cell viabilities in HR model groups were significantly lower than those of group A (P<0.05). LC3 II/LC3 I levels in groups B to D were significantly higher than those of group A (P<0.05), and group D showed the highest LC3 II/LC3 I levels. Cell viabilities in groups B to D were significantly lower than those of group A (P<0.05), with group D showing the lowest cell viabilities (P<0.05). Conclusions: Hypoxia can induce autophagy in rat cardiomyocytes, which can be further activated by reoxygenation; most notable after 12 h. Hypoxia-induced cell injury can be aggravated by reoxygenation. The lowest cell viability was observed at 12 h after reoxygenation; however, cell viability can be recovered after 24 h.

Expression of cyclin-dependent kinase inhibitor p27kip1 in malignant lymphomas

p27kip1 is a cyclin-dependent kinase inhibitor that regulates progression from G1 into S phase. Aberrations in cell cycle control are often observed in tumors d might even be necessary in tumor development. Recent reports showed that low 7kip1 expression is associated with poor prognosis in several tumors and ukemia. To investigate the expression of p27kip1 in malignant lymphomas and ucidate the role of p27kip1 as a possible prognostic indicator, the authors rformed an immunohistochemical staining of p27kip1 correlated with Ki-67 belling index and clinical parameters. p27kip1 expression was reduced variably most malignant lymphomas and inversely correlated with Ki-67 labelling index +AD0-0.0151). Regarding chemotherapeutic response, p271kip1 expression in the mplete remission group showed statistically significant difference in pression compared to the progressive disease group (p+AD0-0.0021). There were gnificant differences in survival between cases with low and high p27kip1 pression (p+AD0-0.0071). In a multivariate Cox analysis, p27kip1 expression was dependent prognostic factors as well as other known prognostic factors cluding age, grade, stage and chemotherapeutic response. In conclusion, the udy suggests that reduced expression of p27kip1 protein may play a role in the thogenesis and biologically aggressive behavior of malignant lymphomas.

Expression of cyclin-dependent kinase inhibitor p27kip1 in malignant lymphomas

p27kip1 is a cyclin-dependent kinase inhibitor that regulates progression from G1 into S phase. Aberrations in cell cycle control are often observed in tumors d might even be necessary in tumor development. Recent reports showed that low 7kip1 expression is associated with poor prognosis in several tumors and ukemia. To investigate the expression of p27kip1 in malignant lymphomas and ucidate the role of p27kip1 as a possible prognostic indicator, the authors rformed an immunohistochemical staining of p27kip1 correlated with Ki-67 belling index and clinical parameters. p27kip1 expression was reduced variably most malignant lymphomas and inversely correlated with Ki-67 labelling index +AD0-0.0151). Regarding chemotherapeutic response, p271kip1 expression in the mplete remission group showed statistically significant difference in pression compared to the progressive disease group (p+AD0-0.0021). There were gnificant differences in survival between cases with low and high p27kip1 pression (p+AD0-0.0071). In a multivariate Cox analysis, p27kip1 expression was dependent prognostic factors as well as other known prognostic factors cluding age, grade, stage and chemotherapeutic response. In conclusion, the udy suggests that reduced expression of p27kip1 protein may play a role in the thogenesis and biologically aggressive behavior of malignant lymphomas.

Regulatory roles of microtubule-associated proteins in neuronal morphogenesis. Involvement of the extracellular matrix

As a result of recent investigations, the cytoskeleton can be viewed as a cytoplasmic system of interconnected filaments with three major integrative levels: self-assembling macromolecules, filamentous polymers, e.g., microtubules, intermediate filaments and actin filaments, and supramolecular structures formed by bundles of these filaments or networks resulting from cross-bridges between these major cytoskeletal polymers. The organization of this biological structure appears to be sensitive to fine spatially and temporally dependent regulatory signals. In differentiating neurons, regulation of cytoskeleton organization is particularly relevant, and the microtubule-associated protein (MAP) tau appears to play roles in the extension of large neuritic processes and axons as well as in the stabilization of microtubular polymers along these processes. Within this context, tau is directly involved in defining neuronal polarity as well as in the generation of neuronal growth cones. There is increasing evidence that elements of the extracellular matrix contribute to the control of cytoskeleton organization in differentiating neurons, and that these regulations could be mediated by changes in MAP activity. In this brief review, we discuss the possible roles of tau in mediating the effects of extracellular matrix components on the internal cytoskeletal arrays and its organization in growing neurons