Dynamic changes in neuronal autophagy and apoptosis in the ischemic penumbra following permanent ischemic stroke.

The temporal dynamics of neuronal autophagy and apoptosis in the ischemic penumbra following stroke remains unclear. Therefore, in this study, we investigated the dynamic changes in autophagy and apoptosis in the penumbra to provide insight into potential therapeutic targets for stroke. An adult Sprague-Dawley rat model of permanent ischemic stroke was prepared by middle cerebral artery occlusion. Neuronal autophagy and apoptosis in the penumbra post-ischemia were evaluated by western blot assay and immunofluorescence staining with antibodies against LC3-II and cleaved caspase-3, respectively. Levels of both LC3-II and cleaved caspase-3 in the penumbra gradually increased within 5 hours post-ischemia. Thereafter, levels of both proteins declined, especially LC3-II. The cerebral infarct volume increased slowly 1-4 hours after ischemia, but subsequently increased rapidly until 5 hours after ischemia. The severity of the neurological deficit was positively correlated with infarct volume. LC3-II and cleaved caspase-3 levels were high in the penumbra within 5 hours after ischemia, and after that, levels of these proteins decreased at different rates. LC3-II levels were reduced to a very low level, but cleaved caspase-3 levels remained high 72 hours after ischemia. These results indicate that there are temporal differences in the activation status of the autophagic and apoptotic pathways. This suggests that therapeutic targeting of these pathways should take into consideration their unique temporal dynamics.

Fates of donor and recipient mitochondrial DNA during generation of interspecies SCNT-derived human ES-like cells.

To investigate nuclear donor and cytoplast recipient mitochondria fate and their effects on generation of interspecies somatic cell nuclear transfer (iSCNT)-derived human embryonic stem (ES)-like cells, iSCNT embryos were reconstructed between enucleated goat oocytes and human neural stem cells (hNSCs). A total of 10.74% cleaved embryos (13/121) developed to blastocyst stage. One typical primary ES-like (tpES-like) colony and two nontypical primary ES-like (non-tpES-like) colonies designated as non-tpES-like cell-1 and non-tpES-like cell-2, respectively, were obtained from the inner cell masses of iSCNT blastocysts. The tpES-like cells expressed ESC markers. Both human and goat mtDNA could be detected in the embryos at 2-8-, 16-32-cell, and blastocyst stages, and in tpES-like colony and two non-tpES-like colonies. Human mtDNA copies per cell from embryos at two- to eight-cell stage to the three colonies maintain almost its original level, whereas 2.88 x 10(5) goat mtDNA copies per oocyte decreased to 10.8 copies per tpES-like cell, 493 copies per non-tpES-like cell-1, and 77.6 copies per non-tpES-like cell-2, resulting in 43.75% (8.4/19.2), 1.24% (6.2/499), and 14.63% (13.3/90.9) mtDNA content in tpES-like cell, non-tpES-like cell-1, and non-tpES-like cell-2 was that of nuclear donor, respectively. Human-specific Tfam and Polg mRNA could be detected in cells of the three colonies. However, tpES-like colony failed to be passaged. The mRNA level of CoxIV encoded by nuclear donor in tpES-like cell was higher than that in non-tpES-like cell, but significantly lower than that of human ESC, suggesting proper nuclear-cytoplasmic communication would not be established in tpES-like cells. Thus, the data suggest that (1) goat oocytes could reprogram human neural stem cells (hNSCs) into embryonic state and further support the inner cell mass (ICM) of iSCNT blastocyst to form tpES-like colony; (2) nuclear donor mtDNA could be replicated and maintain its original level during the reduction of recipient mitochondrial DNA copies, (3) nuclear-cytoplasmic communication and recipient mtDNA copies might affect the derivation of iSCNT-derived ES-like cells.

[S2-->S0 radiative transition of 2,2'-bipyridine doped in silica gel glass].

Doping 2,2'-bipyridine molecules in silica gel glass leads to special spectroscopic properties compared to those dissolved in liquid solutions. For the sample without heat treatment, two broad bands centered at 400 nm and 454 nm respectively, induced by the radiative transition from the first excited level S1 to the ground level S0 and attributed to the emission from an excited dimeric 2,2'-bipyridine species respectively, were observed. After heat-treated at 200 degrees C, the excimer emission at 454 nm disappeared, and the sample exhibited another emission band centered at 325 nm due to the radiative transition from the second excited level S2 to the ground level. S2-->S0 transition resulted from restricting 2,2'-bipyridine molecules in silica networks. Only the structure emission of S2-->S0 transition was observed when heat-treated at 550 degrees C, which indicates that most of 2,2'-bipyridine molecules were entrapped in the cages of Si-O network. The above results can be used to characterize the microstructural evolution of hybrid organic-inorganic optical materials.