Search

Background: Silicon (Si) can confer plant resistance to both abiotic and biotic stress. In the present study, the priming effect of Si on rice (Oryza sativa cv Nipponbare) against the root-knot nematode Meloidogyne graminicola and its histochemical and molecular impact on plant defense mechanisms were evaluated. Results: Si amendment significantly reduced nematodes in rice roots and delayed their development, while no obvious negative effect on giant cells was observed. Increased resistance in rice was correlated with higher transcript levels of defense-related genes (OsERF1, OsEIN2 and OsACS1) in the ethylene (ET) pathway. Si amendment significantly reduced nematode numbers in rice plants with enhanced ET signaling but had no effect in plants deficient in ET signaling, indicating that the priming effects of Si were dependent on the ET pathway. A higher deposition of callose and accumulation of phenolic compounds were observed in rice roots after nematode attack in Si-amended plants than in the controls. Conclusion: These findings indicate that the priming effect may partially depend on the production of phenolic compounds and hydrogen peroxide. Further research is required to model the ethylene signal transduction pathway that occurs in the Si-plant-nematode interaction system and gain a better understanding of Si-induced defense in rice. [ABSTRACT FROM AUTHOR]

Mesenchymal stem cells (MSCs) are a reliable cell source for tissue regeneration. However, the molecular mechanisms underlying the directed differentiation of MSCs remain unclear; thus, their use is limited. Here, we investigate HOXB7 function in the osteogenic differentiation potentials of MSCs using stem cells from apical papilla (SCAPs) and bone marrow stem cells (BMSCs). The HOXB7 gene is highly expressed in BMSCs compared with dental tissue-derived MSCs. We found that, in vitro, over-expression of HOXB7 in SCAPs enhanced alkaline phosphatase (ALP) activity and mineralization. HOXB7 over-expression affected the mRNA expression of osteonectin (ON), collagen alpha-2(I) chain (COL1A2), bone sialoprotein (BSP), and osteocalcin (OCN), led to the expression of the key transcription factor, runt-related transcription factor 2 (RUNX2), and promoted SCAP osteogenic differentiation in vitro. The knock-down of HOXB7 inhibited ALP activity, mineralization, and the expression of ON, BSP, COL1A2, OCN, and RUNX2 in BMSCs in vitro. In addition, transplant experiments in nude mice confirmed that SCAP osteogenesis was triggered when HOXB7 was activated. Furthermore, Over-expression of HOXB7 significantly increased the levels of HOXB7 associated with the BSP promoter by ChIP assays. Taken together, these results indicate that HOXB7 enhances SCAP osteogenic differentiation by up-regulating RUNX2 and directly activating transcript of BSP. Thus, the activation of HOXB7 signaling might improve tissue regeneration mediated by MSCs. These results provide insight into the mechanism underlying the directed differentiation of MSCs.

Background: Sudden internal carotid artery (ICA) occlusive vasospasm is a serious complication of intracranial aneurysm embolization. Conventional spasmolysis with papaverine yields a generally poor outcome. We believe that arterial infusion of lidocaine may offer a better outcome., Materials and Methods: We retrospectively reviewed the outcome of patients treated with either papaverine or lidocaine infusion for vasospasm during embolization., Results: 14 patients undergoing intracranial aneurysm embolization had a ICA occlusive vasospasm. Among the 8 patients who received conventional treatment with papaverine the vasospasm improved partially in 5. In 3 cases, treatment was ineffective. 6 of the patients died within 3 days. 2 patients developed hemispheric infarction and underwent a decompressive craniectomy and subtotal resection of the infarct; 1 of these 2 patients died after 4 months and the other was severely disabled. In the 6 patients treated with lidocaine, spasmolysis and subsequent aneurysm treatment was successful in 5. In 1 patient who had preoperative stenosis of the carotid artery proximal to the aneurysm spasmolysis failed., Conclusions: ICA occlusive spasm is an extremely serious and often lethal complication in embolization of intracranial aneurysms. Conventional treatment with papaverine has a poor outcome, whereas arterial infusion of lidocaine may achieve better results., (© 2012 by Thieme Medical Publishers, Inc.)

Aim: To investigate the effect of Ad-ING4 on proliferation and migration of glioma cells and explore its probable mechanism., Methods: U251 were infected with Ad-ING4. ING4 gene expression was evaluated by RT-PCR. MTT assay was adopted to evaluate the effect of ING4 on proliferation of U251; Boyden chamber assay was used to check the effect of ING4 on the migration of U251. In ING4 transfected U251, Western blot was used for detecting NGF and TrkA expression; Pull-down assay was used for detecting active RhoA expression., Results: ING4 was overexpressed in Ad-ING4 transfected U251 cells. ING4 inhibited proliferation and migration of U251 significantly. Moreover, overexpression of ING4 result in depression of NGF, TrkA and active RhoA., Conclusion: ING4 mediated inhibition of the proliferation and migration of human glioma cells by down regulating NGF, TrkA and active RhoA expression.