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81.
In this study, using the quadratic saturation 310 D-optimal design method, we examined the effect of kinetin (KT), gibberellic acid (GA), and naphthalene acetic acid (NAA) on microrhizome production in ginger. The effect of GA on rhizome induction was larger than that of KT or NAA. Using simulation and optimality selection for tissue culture, we found that concentrations of GA, KT, and NAA of 1.33–2.35, 0.49–0.66, and 0.62 g/l, respectively, gave a microrhizome weight of over 0.25 g. The optimal conditions for microrhizome production were 80 g/l sucrose, 2 × MS macro-elements, and 1 × MS micro-elements, with a photoperiod of 24L:0D (light/dark). At the same time, 100% survival could be achieved on transfer of the in vitro ginger plantlets with microrhizomes to soil.  相似文献   
82.
Some anesthetics have been suggested to induce Alzheimer??s disease (AD) neuro-pathogenesis. Increasing evidence indicates that hyperphosphorylated tau plays a key role in the pathogenic events that occur in AD. Isoflurane has been shown to induce apoptosis, which leads to accumulation of amyloid-?? (A??). We set out to investigate whether isoflurane can induce apoptosis by increasing hyperphosphorylated tau in A??25?C35-induced cells and the underlying mechanism. Cultured rat pheochromocytoma cells (PC12) were exposed to 20?mM A??25?C35 alone or with 2?% isoflurane for 6?h. The cell viability was determined by MTT assay, and the apoptosis rate was detected by flowcytometry. Western blotting and immunocytochemical staining were performed to observe the protein expression of Bcl-2 family, tau phosphorylation of different sites, tau protein kinases and phosphatases. Additionally, lithium chloride was administered to all above groups to investigate the changes of apoptosis rate and protein expression. The apoptosis rate was significantly increased in A??25?C35 group compared with the others groups, which was accompanied by bcl-2 decline, and the phosphorylation of glycogen synthase kinase-3??(GSK-3??) and tau of two sites increased. LiCl attenuated the cellular apoptosis by inhibition the level of tau phosphorylation. Isoflurane upregulated the level of phosphorylated GSK-3??, which phosphorylate tau at different sites, and aggravated the apoptotic rate of the A??25?C35-induced PC12 cells. It indicated that isoflurane-induced tau phosphorylation might play a role in the AD-like development.  相似文献   
83.
Monoclonal antibodies constitute a robust class of therapeutic proteins. Their stability, resistance to stress conditions and high solubility have allowed the successful development and commercialization of over 40 antibody-based drugs. Although mAbs enjoy a relatively high probability of success compared with other therapeutic proteins, examples of projects that are suspended due to the instability of the molecule are not uncommon. Developability assessment studies have therefore been devised to identify early during process development problems associated with stability, solubility that is insufficient to meet expected dosing or sensitivity to stress. This set of experiments includes short-term stability studies at 2−8 þC, 25 þC and 40 þC, freeze-thaw studies, limited forced degradation studies and determination of the viscosity of high concentration samples. We present here three case studies reflecting three typical outcomes: (1) no major or unexpected degradation is found and the study results are used to inform early identification of degradation pathways and potential critical quality attributes within the Quality by Design framework defined by US Food and Drug Administration guidance documents; (2) identification of specific degradation pathway(s) that do not affect potency of the molecule, with subsequent definition of proper process control and formulation strategies; and (3) identification of degradation that affects potency, resulting in program termination and reallocation of resources.  相似文献   
84.
Castration-resistant progression of prostate cancer after androgen deprivation therapies remains the most critical challenge in the clinical management of prostate cancer. Resurgent androgen receptor (AR) activity is an established driver of castration-resistant progression, and upregulation of the full-length AR (AR-FL) and constitutively-active AR splice variants (AR-Vs) has been implicated to contribute to the resurgent AR activity. We reported previously that ginsenoside 20(S)-protopanaxadiol-aglycone (PPD) can reduce the abundance of both AR-FL and AR-Vs. In the present study, we further showed that the effect of PPD on AR expression and target genes was independent of androgen. PPD treatment resulted in a suppression of ligand-independent AR transactivation. Moreover, PPD delayed castration-resistant regrowth of LNCaP xenograft tumors after androgen deprivation and inhibited the growth of castration-resistant 22Rv1 xenograft tumors with endogenous expression of AR-FL and AR-Vs. This was accompanied by a decline in serum prostate-specific antigen levels as well as a decrease in AR levels and mitoses in the tumors. Notably, the 22Rv1 xenograft tumors were resistant to growth inhibition by the next-generation anti-androgen enzalutamide. The present study represents the first to show the preclinical efficacy of PPD in inhibiting castration-resistant progression and growth of prostate cancer. The findings provide a rationale for further developing PPD or its analogues for prostate cancer therapy.  相似文献   
85.

Background

Several case-control studies have been performed to examine the association of genetic variants in lysyl oxidase (LOX) with keratoconus. However, the results remained inconclusive and great heterogeneity might exist across populations.

Method

A comprehensive literature search for studies that published up to June 25, 2015 was performed. Summary odds ratios (OR) and 95% confidence intervals (CI) of each single nucleotide polymorphism (SNP) were estimated with fixed effects model when I 2<50% in the test for heterogeneity or random effects model when I 2>50%. Publication bias was evaluated using funnel plots and Egger’s test.

Results

A total of four studies including 1,467 keratoconus cases and 4,490 controls were involved in this meta-analysis. SNPs rs2956540 and rs10519694 showed significant association with keratoconus, with ORs of 0.71 (95% CI: 0.63–0.80, P = 1.43E-08) and 0.77 (95% CI: 0.61–0.97, P = 0.026), respectively. In contrast, our study lacked sufficient evidences to support the association of rs1800449/rs2288393 with keratoconus across populations.

Conclusion

This meta-analysis suggested that two LOX variants, rs2956540 and rs10519694, may affect individual susceptibility to keratoconus, while distinct heterogeneity existed within this locus. Larger-scale and multi-ethnic genetic studies on keratoconus are required to further validate the results.  相似文献   
86.
87.
88.
心绞痛的痛觉产生机制   总被引:2,自引:0,他引:2  
心绞痛是心肌细胞缺血缺氧的信号。损伤的心肌细胞释放致痛物质腺苷、H 、K ,并激活激肽系统产生缓激肽,刺激感觉神经末稍产生神经冲动,经交感、迷走神经进入中枢神经系统,沿内脏感觉传导通路到达大脑皮层形成痛觉。如果缺血程度较轻或疼痛传导通路异常,病人可发生无痛性心肌缺血。  相似文献   
89.
The ligand-gated outer membrane porin FepA serves Escherichia coli as the receptor for the siderophore ferric enterobactin. We characterized the ability of seven analogs of enterobactin to supply iron via FepA by quantitatively measuring the binding and transport of their 59Fe complexes. The experiments refuted the idea that chirality of the iron complex affects its recognition by FepA and demonstrated the necessity of an unsubstituted catecholate coordination center for binding to the outer membrane protein. Among the compounds we tested, only ferric enantioenterobactin, the synthetic, left-handed isomer of natural enterobactin, and ferric TRENCAM, which substitutes a tertiary amine for the macrocyclic lactone ring of ferric enterobactin but maintains an unsubstituted catecholate iron complex, were recognized by FepA (Kd ≈ 20 nM). Ferric complexes of other analogs (TRENCAM-3,2-HOPO; TREN-Me-3,2-HOPO; MeMEEtTAM; MeME-Me-3,2-HOPO; K3MECAMS; agrobactin A) with alterations to the chelating groups and different net charge on the iron center neither adsorbed to nor transported through FepA. We also compared the binding and uptake of ferric enterobactin by homologs of FepA from Bordetella bronchisepticus, Pseudomonas aeruginosa, and Salmonella typhimurium in the native organisms and as plasmid-mediated clones expressed in E. coli. All the transport proteins bound ferric enterobactin with high affinity (Kd ≤ 100 nM) and transported it at comparable rates (≥50 pmol/min/109 cells) in their own particular membrane environments. However, the FepA and IroN proteins of S. typhimurium failed to efficiently function in E. coli. For E. coli, S. typhimurium, and P. aeruginosa, the rate of ferric enterobactin uptake was a sigmoidal function of its concentration, indicating a cooperative transport reaction involving multiple interacting binding sites on FepA.  相似文献   
90.
Pre‐eclampsia (PE) is deemed an ischemia‐induced metabolic disorder of the placenta due to defective invasion of trophoblasts during placentation; thus, the driving role of metabolism in PE pathogenesis is largely ignored. Since trophoblasts undergo substantial glycolysis, this study aimed to investigate its function and regulatory mechanism by AMPK in PE development. Metabolomics analysis of PE placentas was performed by gas chromatography–mass spectrometry (GC–MS). Trophoblast‐specific AMPKα1‐deficient mouse placentas were generated to assess morphology. A mouse PE model was established by Reduced Uterine Perfusion Pressure, and placental AMPK was modulated by nanoparticle‐delivered A769662. Trophoblast glucose uptake was measured by 2‐NBDG and 2‐deoxy‐d‐[3H] glucose uptake assays. Cellular metabolism was investigated by the Seahorse assay and GC–MS.PE complicated trophoblasts are associated with AMPK hyperactivation due not to energy deficiency. Thereafter, AMPK activation during placentation exacerbated PE manifestations but alleviated cell death in the placenta. AMPK activation in trophoblasts contributed to GLUT3 translocation and subsequent glucose metabolism, which were redirected into gluconeogenesis, resulting in deposition of glycogen and accumulation of phosphoenolpyruvate; the latter enhanced viability but compromised trophoblast invasion. However, ablation of AMPK in the mouse placenta resulted in decreased glycogen deposition and structural malformation. These data reveal a novel homeostasis between invasiveness and viability in trophoblasts, which is mechanistically relevant for switching between the ‘go’ and ‘grow’ cellular programs.

Pre‐eclampsia (PE) is associated with trophoblast AMPK hyperactivation, presumably due to LKB1 phosphorylation, and glucose uptake is consequently increased via trafficking of GLUT3 from the cytosol to the plasma membrane. Such translocation enhances glycolytic flux and redirects glucose metabolic intermediates into gluconeogenesis, resulting in PEP accumulation, which not only benefits cell survival but also suppresses invasion by repressing MMPs, and thus in turn modulates switching between the ‘go’ and ‘grow’ cellular programs.  相似文献   
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