Palladium-catalyzed arylation of β-methylene C(sp3)–H bonds at room temperature: desymmetrization of simple cycloalkyl carboxylic acids

A new protocol for Pd-catalyzed β methylene C–H arylation of N-quinolyl cycloalkylcarboxamides with aryl iodides at room temperature is reported.

Hippocampal neurogenesis in the APP/PS1/nestin-GFP triple transgenic mouse model of Alzheimer's disease

Alzheimer's disease (AD) is one of the most common causes of dementia. Although the exact mechanisms of AD are not entirely clear, the impairment in adult hippocampal neurogenesis has been reported to play a role in AD. To assess the relationship between AD and neurogenesis, we studied APP/PS1/nestin-green fluorescent protein (GFP) triple transgenic mice, a well-characterized mouse model of AD, which express GFP under the control of the nestin promoter. Different ages of AD mice and their wild-type littermates (WT) were used in our study. Immunofluorescent staining showed that neurogenesis occurred mainly in the subgranular zone (SGZ) of the dentate gyrus (DG) and subventricular zone (SVZ) of the lateral ventricles (LVs). The expression of neural stem cells (NSCs) (nestin) and neural precursors such as doublecortin (DCX) and GFAP in AD mice were decreased with age, as well as there being a reduction in 5-bromo-2-deoxyuridine (BrdU)-positive cells, when compared to WT. However, the number of maturate neurons (NeuN) was not significantly different between AD mice and wild-type controls, and NeuN changed only slightly with age. By Golgi-Cox staining, the morphologies of dendrites were observed, and significant differences existed between AD mice and wild-type controls. These results suggest that AD has a far-reaching influence on the regulation of adult hippocampal neurogenesis, leading to a gradual decrease in the generation of neural progenitors (NPCs), and inhibition of the differentiation and maturation of neurons.

Conduction Mechanisms in CVD-Grown Monolayer MoS2 Transistors: From Variable-Range Hopping to Velocity Saturation

We fabricate transistors from chemical vapor deposition-grown monolayer MoS2 crystals and demonstrate excellent current saturation at large drain voltages (Vd). The low-field characteristics of these devices indicate that the electron mobility is likely limited by scattering from charged impurities. The current-voltage characteristics exhibit variable range hopping at low Vd and evidence of velocity saturation at higher Vd. This work confirms the excellent potential of MoS2 as a possible channel-replacement material and highlights the role of multiple transport phenomena in governing its transistor action.

ENaC mediates human extravillous trophblast cell line (HTR8/SVneo) invasion by regulating levels of matrix metalloproteinase 2 (MMP2)

INTRODUCTION

Placenta dysfunction is thought to be the major etiological factor related to preeclampsia. The epithelial sodium channel (ENaC) has been localized in the apical plasma membrane of epithelia, mediating the active reabsorption of sodium in kidney, and be involved in the regulation of blood pressure. In previous studies, we found that the reduced expression of ENaC on placenta in preeclampsia patients. The aim of this study was to determine the role of MMP2 in the ENaC-induced trophoblast cell invasion ability, which is closely related to the occurrence of preeclampsia.

METHODS

Here we checked whether pregnancy related hormones human chorionic gonadotropin (HCG), prolactin and aldosterone could affect ENaC expression in the first trimester extravillous trophoblast cell line (HTR8/SVneo) by RT-PCR and Western blot. Cell invasion was studied by matrigel invasion assay. Tube formation assay was used to investigate the interaction between trophoblast cells and endothelial cells. The effects of ENaC on MMP2 were further determined by RT-PCR, western blot and gelatin zymography.

RESULTS

We demonstrated that HCG, prolactin and aldosterone could up-regulate the expression of αENaC in protein levels. Trophoblast cell invasion ability is stimulated when αENaC was up-regulated by aldosterone, and inhibited when ENaC was down-regulated by amiloride and αENaC specific RNAi (SiENA/ENaC). The interaction between HTR8/SVneo cells and HUVEC cells was enhanced when treated with aldosterone and weakened when treated with amiloride and SiRNA/ENaC. Amiloride and SiRNA/ENaC could inhibit MMP2 expression and activity.

DISSCUTION

Aldosterone induced ENaC activity is important for trophoblast cells invasion. The results also indicate that ENaC could mediate trophoblast cells invasion ability through regulating expression and activity of matrix metalloproteinase-2 (MMP2).

Palladium-catalyzed alkylation of unactivated C(sp3)–H bonds with primary alkyl iodides at room temperature: facile synthesis of β-alkyl α-amino acids

Practical synthesis of β-alkyl α-amino acidsviaC(sp³)–H alkylation at room temperature.

Rapid determination of fenoldopam in human plasma by UPLC-MS/MS for pharmacokinetic analysis in patients

We developed and validated a rapid, selective, and sensitive ultra-performance liquid-chromatography mass-spectrometry (UPLC-MS/MS) method for quantifying fenoldopam in human plasma for pharmacokinetic studies. Fenoldopam and the internal-standard (IS), oxazepam, were isolated from human plasma by liquid-liquid extraction using ethyl acetate after alkalization, and were separated on a 2.1×100 mm Acquity UPLC HSS T3 C18 column (inside diameter, 1.8 μm) using a mobile phase of water (0.05% formic acid) and acetonitrile gradient elution. The fenoldopam and IS were eluted at 1.07 and 2.32 min, respectively. Quantification was performed using positive-ion electrospray-ionization (ESI), and the fenoldopam and IS responses were optimized at the m/z 306.16→107.10 and m/z 287.1→241.01 transitions, respectively. The assay was validated over the linear range of 0.1-40 ng/mL fenoldopam with intra- and interassay precision <13.21%. The matrix effect of normal and hemolyzed plasma was 94.9-101.6%. Fenoldopam was stable for ≥34 days at -70 °C in normal and hemolyzed plasma containing ascorbic acid as a stabilizer. This method can be successfully applied in pharmacokinetic studies of fenoldopam in hypertensive patients.

Matrine-induced apoptosis of human nasopharyngeal carcinoma cells via in vitro vascular endothelial growth factor-A/extracellular signal-regulated kinase1/2 pathway inactivation

Matrine, a main active extract from Sophora flavescens Ait, has been demonstrated to exert anticancer effects on various cancer cell lines, such as malignant melanoma, breast cancer, and lung cancer. However, it is currently unclear whether matrine could also elicit an inhibitory effect on growth of nasopharyngeal carcinoma (NPC), let alone the possible molecular mechanisms. Therefore, in a previous study, we investigated matrine-induced proliferation inhibition and apoptosis in NPC cells. It was shown that proliferation of human NPC cells (CNE1 and CNE2) was significantly diminished by matrine in a dose- and time-dependent manner, and apoptosis was induced in both 2 NPC cells, particularly in CNE2 cells. Moreover, the increased apoptosis rate in matrine-treated CNE2 cells confirmed the proapoptotic activity of matrine. We further found that matrine treatment dose- and time-dependently reduced the levels of vascular endothelial growth factor-A (VEGF-A), and inactivated extracellular signal-regulated kinase1/2 (ERK1/2), followed by increased expression of downstream target caspase-3. Overall, we conclude that matrine could induce apoptosis of human NPC cells via VEGF-A/ERK1/2 pathway, which supports the potential use of matrine in clinically treating NPC.

The effect of HIF-1α on glucose metabolism, growth and apoptosis of pancreatic cancerous cells

OBJECTIVES

The aim of this study is to explore the possible role of HIF-1α in glucose metabolism, proliferation and apoptosis of pancreatic cancerous cells.

METHOD

The pancreatic cancerous BxPC-3 cells were cultured in normoxia or hypoxia (3% O2), respectively. Cell proliferation was determined by MTT assay, apoptosis was determined by Annexin V/PI staining. Expression of Pyruvate dehydrogenase kinase (PDK1), Lactate dehydrogenase (LDHA), pyruvate kinase M2 (PKM2) and citrate synthase (CS) was determined by Western-blot and Realtime PCR.

RESULTS

Under hypoxia, the expression of HIF-1α and the lactate production were increased. The expression of glucose metabolic enzymes PDK1, LDHA, PKM2 was also increased compared with that under aerobic condition. Hypoxia treatment had little effect on expression of CS. Under hypoxia, knockdown of HIF-1α inhibited the production of lactate and the expression of PDK1, LDHA and PKM2. Knockdown of HIF-1α repressed the growth of pancreatic cancer BxPC-3 cells and induced apoptosis of the cells under hypoxia.

CONCLUSION

Under hypoxia, the expression of HIF-1α is induced, leading to the increase of glycolysis in BxPC-3 cells possibly through upregulation of the enzymes related to glycolysis. HIF-1α knockdown can inhibit the prolife ratio and promote apoptosis of pancreatic cancerous BxPC-3 cells in vitro.

Surface characterization and osteoblast response to a functionally graded hydroxyapatite/fluoro-hydroxyapatite/titanium oxide coating on titanium surface by sol-gel method

OBJECTIVES

To improve efficacy of current titanium and its alloys, in bioactivity and speed of osseointegration, of orthopaedic implants.

MATERIALS AND METHODS

A novel triple-layered functional graded coating, consisting of a porous hydroxyapatite (HA) outermost layer, fluoro-HA (FHA) intermediate layer and titanium oxide (TiO2 ) innermost layer, was created on a titanium substrate by a multistep sol-gel method. X-ray diffraction analysis showed TiO2 anatase and apatite crystallization in the coating.

RESULTS

Morphological analysis performed by scanning electron microscopy showed excellent bonding between coating and substrate, with a thickness of ~2 μm. Scratch testing found favourable adhesion strength of the composite coating. In addition, optical microscope images suggested good biocompatibility. Considering thet in vitro cell response, osteoblasts on the coating exhibited higher cell proliferation and ALP activity compared to pure titanium and HA coating, and demonstrated excellent coating bioactivity.

CONCLUSIONS

Current results indicated that the novel TiO2 /FHA/HA coating has promising clinical applications in orthopaedic and dental implantation.

[Clinical control study of laparoscopic versus open surgery for rectal cancer]

OBJECTIVE

To evaluate the safety and short-term outcomes of laparoscopic-assisted surgery for rectal cancer by comparing the efficacy of laparoscopy and open surgery.

METHODS

Clinical data of patients with rectal cancer treated by laparoscopy or open surgery in Zhongshan Hospital from April 2011 to June 2012 were analyzed retrospectively, and the clinical outcomes between the two groups were compared.

RESULTS

Ninety-six rectal cancer patients undergoing laparoscopic surgery(LS) were enrolled. A total of 216 rectal cancer patients underwent open surgery(OS). There was no operative death in both groups. In LS and OS group, the overall completion rates of TME were 86.4%(83/96) vs. 89.3%(193/216)(P>0.05) respectively, and the overall anal reservation rates were 78.1%(75/96) vs. 75.0%(162/216)(P>0.05) respectively. The mean distance to proximal resection margin and distal resection margin respectively were (10.3±4.1) cm vs.(10.0±4.3) cm(P>0.05) and (3.4±0.9) cm vs. (3.6±1.4) cm(P>0.05) respectively. The mean number of harvested lymph nodes respectively were (12.8±5.2) vs.(13.7±6.4)(P>0.05). Compared to OS, LS presented less blood loss [(98.0±28.7) ml vs. (175.0±41.0) ml, P<0.05], shorter postoperative hospital stay [(9.4±4.9) d vs.(11.6±6.2) d, P<0.05], quicker postoperative recovery of bowel function[(2.7±0.9) d vs. (3.4±0.9) d, P<0.05], shorter postoperative time to intake semi-solid[(3.7±1.2) d vs. (4.4±1.5) d, P<0.05], less postoperative complications(15.6% vs. 25.9%, P<0.05), but longer operative time[(155.7±48.4) min vs. (120.0±26.7) min, P<0.05]. Postoperative follow-up was 6 to 24 months, and the local recurrence of LS and OS was 2.1% and 2.3%(P>0.05).

CONCLUSION

Laparoscopic surgery can obtain the same radical efficacy for rectal cancer as compared to open surgery.

Neither cytochrome P450 family genes nor neuroendocrine factors could independently predict the SSRIs treatment in the Chinese Han population

OBJECTIVE

This study was intended to explore the relationship between the genetic polymorphisms of the 8 single nucleotide polymorphisms (SNPs) at CYP genes, neuroendocrine factors and the response to selective serotonin reuptake inhibitors (SSRIs) in Chinese Han depressive patients.

METHOD

This was a 6-week randomized controlled trial consisting of 290 Chinese Han depressive patients treated with SSRIs. 8 SNPs of CYP450 genes and 7 neuroendocrine factors were detected. Allele and genotype frequencies were compared between responders and non-responders. The relationships between neuroendocrine factors and treatment response were also analyzed.

RESULTS

No significant differences were found in clinical features between 2 groups at the baseline. No statistical correlation was found between either the genotype or allele frequencies of SNPs in CYP1A2, CYP2C19, or CYP2D6 gene and the -efficacy of SSRIs. There were strong linkage disequilibria between rs4986894, rs1853205, and rs12767583 of CYP2C19 genes, and rs2472299, rs2472300 of CYP1A2 genes. No associations were found between the above haplotypes and the antidepressant response. No neuroendocrine factor was a significant predictor for a response to SSRI antidepressants independently. The combination of neuroendocrine factors, however, predicted the response by 76.1%.

CONCLUSION

There were no significant associations between the 6 SNPs of CYP gene polymorphisms and SSRI response. Neither cytochrome P450 family genes nor neuroendocrine factors independently predict the patients' response to the antidepressants separately. A combination of neuroendocrine factors, however, does have the potential to predict the response.

Degradation of typical N-nitrosodimethylamine (NDMA) precursors and its formation potential in anoxic-aerobic (AO) activated sludge system

N-nitrosodimethylamine (NDMA) is an emerging disinfection byproduct. Removal of its potential precursors is considered as an effective method to control NDMA. In this study, four typical NDMA precursors (dimethylamine (DMA), trimethylamine (TMA), dimethylformamide (DMFA) and dimethylaminobenzene (DMAB)) were selected, and their removal capacities by activated sludge were investigated. Batch experiments indicated that removal of NDMA precursors was better under aerobic condition than anoxic condition; and their specific degradation rates follow the order of DMA > TMA > DMFA > DMAB. In anoxic-aerobic (AO) activated sludge system, the optimal hydraulic retention time and sludge retention time were 10 h and 20 d, respectively, for the removal of both NDMA precursors (four selected NDMA precursors and NDMA formation potential (NDMA FP)) and nutrients. Our results also suggested that there was a positive correlation between NDMA FP and dissolved organic nitrogen (DON) in wastewater. The removal efficiency of NDMA FP was in the range of 46.8-72.5% in the four surveyed wastewater treatment plants except the one which adopted chemically enhanced primary process. The results revealed that the AO system had the advantage of removing NDMA FP. Our results are helpful for the knowledge of the removals of NDMA precursors during activated sludge treatment processes.

Selective neuronal differentiation of neural stem cells induced by nanosecond microplasma agitation

An essential step for therapeutic and research applications of stem cells is their ability to differentiate into specific cell types. Neuronal cells are of great interest for medical treatment of neurodegenerative diseases and traumatic injuries of central nervous system (CNS), but efforts to produce these cells have been met with only modest success. In an attempt of finding new approaches, atmospheric-pressure room-temperature microplasma jets (MPJs) are shown to effectively direct in vitro differentiation of neural stem cells (NSCs) predominantly into neuronal lineage. Murine neural stem cells (C17.2-NSCs) treated with MPJs exhibit rapid proliferation and differentiation with longer neurites and cell bodies eventually forming neuronal networks. MPJs regulate ~75% of NSCs to differentiate into neurons, which is a higher efficiency compared to common protein- and growth factors-based differentiation. NSCs exposure to quantized and transient (~150 ns) micro-plasma bullets up-regulates expression of different cell lineage markers as β-Tubulin III (for neurons) and O4 (for oligodendrocytes), while the expression of GFAP (for astrocytes) remains unchanged, as evidenced by quantitative PCR, immunofluorescence microscopy and Western Blot assay. It is shown that the plasma-increased nitric oxide (NO) production is a factor in the fate choice and differentiation of NSCs followed by axonal growth. The differentiated NSC cells matured and produced mostly cholinergic and motor neuronal progeny. It is also demonstrated that exposure of primary rat NSCs to the microplasma leads to quite similar differentiation effects. This suggests that the observed effect may potentially be generic and applicable to other types of neural progenitor cells. The application of this new in vitro strategy to selectively differentiate NSCs into neurons represents a step towards reproducible and efficient production of the desired NSC derivatives.

Recruitment of trimeric proliferating cell nuclear antigen by G1-phase cyclin-dependent kinases following DNA damage with platinum-based antitumour agents

BACKGROUND

In cycling tumour cells, the binary cyclin-dependent kinase Cdk4/cyclin D or Cdk2/cyclin E complex is inhibited by p21 following DNA damage to induce G1 cell-cycle arrest. However, it is not known whether other proteins are also recruited within Cdk complexes, or their role, and this was investigated.

METHODS

Ovarian A2780 tumour cells were exposed to the platinum-based antitumour agent 1R,2R-diaminocyclohexane(trans-diacetato)(dichloro)platinum(IV) (DAP), which preferentially induces G1 arrest in a p21-dependent manner. The Cdk complexes were analysed by gel filtration chromatography, immunoblot and mass spectrometry.

RESULTS

The active forms of Cdk4 and Cdk2 complexes in control tumour cells have a molecular size of ~140 kDa, which increased to ~290 kDa when inhibited following G1 checkpoint activation by DAP. Proteomic analysis identified Cdk, cyclin, p21 and proliferating cell nuclear antigen (PCNA) in the inhibited complex, and biochemical studies provided unequivocal evidence that the increase in ~150 kDa of the inhibited complex is consistent with p21-dependent recruitment of PCNA as a trimer, likely bound to three molecules of p21. Although p21 alone was sufficient to inhibit the Cdk complex, PCNA was critical for stabilising p21.

CONCLUSION

G1 Cdk complexes inhibited by p21 also recruit PCNA, which inhibits degradation and, thereby, prolongs activity of p21 within the complex.

Fast energy relaxation of hot carriers near the Dirac point of graphene

We investigate energy relaxation of hot carriers in monolayer and bilayer graphene devices, demonstrating that the relaxation rate increases significantly as the Dirac point is approached from either the conduction or valence band. This counterintuitive behavior appears consistent with ideas of charge puddling under disorder, suggesting that it becomes very difficult to excite carriers out of these localized regions. These results therefore demonstrate how the peculiar properties of graphene extend also to the behavior of its nonequilibrium carriers.

Topographical distribution pattern of cervical intraepithelial neoplasia across the cervix

OBJECTIVE

The distribution of cervical intraepithelial neoplasia (CIN) lesions across the cervix was determined.

METHODS

A total of 575 women whose pathological diagnosis after cervical conization was confirmed as CIN were studied; 146 had low-grade CIN and 429 had high-grade CIN. CIN lesion location on the cervix was recorded using 12-h clock face notation.

RESULTS

In both groups, 12 o'clock was the most common and 2 o'clock the least common lesion location. The most severe lesions were most often located at 8 o'clock and 7 o'clock, in the low- and high-grade groups, respectively. The 2 o'clock site was the least frequent site for the most severe lesion in both groups. Lesions were found more frequently on the posterior lip of the cervix than on the anterior lip, and on the right side of the cervix than on the left side, in both groups.

CONCLUSIONS

The distribution of CIN lesions is not randomly distributed across the cervix. The 12, 8 and 7 o'clock sites, and the posterior lip and right side of the cervix, should be targeted during colposcopy-directed biopsy of patients with CIN lesions as this may improve diagnostic accuracy.

Rasgrp2 regulates the permissiveness of NIH3T3 cells to a herpes simplex virus 1 mutant with inactivated ICP34.5 gene

We have previously reported that mtHSV, a herpes simplex virus 1 (HSV-1) mutant with an inactivated gene for β-galactosidase, can efficiently lyse tumor but not normal cells. However, the mechanism of this selective oncolytic activity is so far unclear. In this study, using the phage display screening we identified the cellular protein binding to HSV-1 mutant (mtHSV) as (Ras guanyl releasing protein 2) Rasgrp2 which regulates the Ras signaling pathway. Rasgrp2 was found to bind directly to purified mtHSV as well as to mtHSV present within infected HeLa cells where it aggregated on the cell membrane. NIH3T3 cells were found nonpermissive to mtHSV but they became permissive following transformation with the Rasgrp2 gene. This effect was linked to the activation of the Ras-PKR signaling pathway. These observations indicate a key role of Rasgrp2 in the mtHSV infection of NIH3T3 cells and are important for the potential use of mtHSV in cancer therapy.