Perioperative dexmedetomidine and 5-year survival in patients undergoing cardiac surgery.

BACKGROUND: Dexmedetomidine sedation has been associated with favourable outcomes after surgery. We aimed to assess whether perioperative dexmedetomidine use is associated with improved survival after cardiac surgery. METHODS: This retrospective cohort study included 2068 patients undergoing on-pump coronary artery bypass grafting and/or valve surgery. Among them, 1029 patients received dexmedetomidine, and 1039 patients did not. Intravenous dexmedetomidine infusion of 0.007 µg kg-1 min-1 was initiated before or immediately after cardiopulmonary bypass and lasted for < 24 h. The primary outcome was 5-year survival after cardiac surgery. The propensity scores matching (PSM), inverse probability of treatment weighting (IPTW), and overlap weighting approaches were used to minimise bias. Survival analyses were performed with Cox proportional-hazard models. RESULTS: The median age was 63 yr old and the male to female ratio was 71:29 in both groups. Baseline covariates were balanced between groups after adjustment using PSM, IPTW, or overlap weighting. Patients receiving dexmedetomidine in cardiac surgical procedures had higher survival during postoperative 5 yr in unadjusted analysis (hazard ratio [HR]=0.63; 95% confidence interval [CI], 0.51-0.78; P<0.001), and after adjustment with PSM (HR=0.63; 95% CI, 0.45-0.89; P=0.009), IPTW (HR=0.70; 95% CI, 0.51-0.95; P=0.023), or overlap weighting (HR=0.67; 95% CI, 0.51-0.89; P=0.006). The 5-yr mortality rate after cardiac surgery was 13% and 20% in the dexmedetomidine and non-dexmedetomidine groups, respectively (PSM adjusted odds ratio=0.61; 95% CI, 0.42-0.89; P=0.010). CONCLUSION: Perioperative dexmedetomidine infusion was associated with improved 5-yr survival in patients undergoing cardiac surgery.

Multiscale architectures boosting thermoelectric performance of copper sulfide compound.

Owing to their high performance and earth abundance, copper sulfides (Cu2-x S) have attracted wide attention as a promising medium-temperature thermoelectric material. Nanostructure and grain-boundary engineering are explored to tune the electrical transport and phonon scattering of Cu2-x S based on the liquid-like copper ion. Here multiscale architecture-engineered Cu2-x S are fabricated by a room-temperature wet chemical synthesis combining mechanical mixing and spark plasma sintering. The observed electrical conductivity in the multiscale architecture-engineered Cu2-x S is four times as much as that of the Cu2-x S sample at 800 K, which is attributed to the potential energy filtering effect at the new grain boundaries. Moreover, the multiscale architecture in the sintered Cu2-x S increases phonon scattering and results in a reduced lattice thermal conductivity of 0.2 W·m-1·K-1 and figure of merit (zT) of 1.0 at 800 K. Such a zT value is one of the record values in copper sulfide produced by chemical synthesis. These results suggest that the introduction of nanostructure and formation of new interface are effective strategies for the enhancement of thermoelectric material properties. SUPPLEMENTARY INFORMATION: The online version of this article (10.1007/s12598-020-01698-6) contains supplementary material, which is available to authorized users.

Lipofection-mediated genome editing using DNA-free delivery of the Cas9/gRNA ribonucleoprotein into plant cells.

KEY MESSAGE: A novel and robust lipofection-mediated transfection approach for the use of DNA-free Cas9/gRNA RNP for gene editing has demonstrated efficacy in plant cells. Precise genome editing has been revolutionized by CRISPR/Cas9 systems. DNA-based delivery of CRISPR/Cas9 is widely used in various plant species. However, protein-based delivery of the in vitro translated Cas9/guide RNA (gRNA) ribonucleoprotein (RNP) complex into plant cells is still in its infancy even though protein delivery has several advantages. These advantages include DNA-free delivery, gene-edited host plants that are not transgenic, ease of use, low cost, relative ease to be adapted to high-throughput systems, and low off-target cleavage rates. Here, we show a novel lipofection-mediated transfection approach for protein delivery of the preassembled Cas9/gRNA RNP into plant cells for genome editing. Two lipofection reagents, Lipofectamine 3000 and RNAiMAX, were adapted for successful delivery into plant cells of Cas9/gRNA RNP. A green fluorescent protein (GFP) reporter was fused in-frame with the C-terminus of the Cas9 protein and the fusion protein was successfully delivered into non-transgenic tobacco cv. 'Bright Yellow-2' (BY2) protoplasts. The optimal efficiencies for Lipofectamine 3000- and RNAiMAX-mediated protein delivery were 66% and 48%, respectively. Furthermore, we developed a biolistic method for protein delivery based on the known proteolistics technique. A transgenic tobacco BY2 line expressing an orange fluorescence protein reporter pporRFP was targeted for knockout. We found that the targeted mutagenesis frequency for our Lipofectamine 3000-mediated protein delivery was 6%. Our results showed that the newly developed lipofection-mediated transfection approach is robust for the use of the DNA-free Cas9/gRNA technology for genome editing in plant cells.

Parthenolide ameliorates intracerebral hemorrhage-induced brain injury in rats.

Neuroinflammation and oxidative stress are key contributors to intracranial hemorrhage (ICH)-induced brain injury. Parthenolide (PN) is a sesquiterpene lactone that has been observed to have antioxidative, anti-inflammatory, and neuroprotective potentials. However, the role of PN in ICH remains unclear. Therefore, we investigated the neuroprotective effects and underlying mechanisms of PN on an experimental model of ICH in rats. Our results showed that PN treatment improved neurological deficit and brain edema in ICH rats. The ipsilateral hemispheres of the brain were separated and homogenized. The concentrations of TNF-α, interleukin (IL)-6, and IL-17 in the homogenates were detected by enzyme-linked immunosorbent assay. We found that PN inhibited the production of proinflammatory cytokines in an ICH rat model. The ROS and glutathione (GSH) levels, as well as the activity of superoxide dismutase (SOD) in the homogenates were measured. ICH caused an increase in ROS level, and the decreases in GSH level and SOD activity were mitigated by PN treatment. Furthermore, PN significantly suppressed the expressions of active caspase-3 and Bax in ipsilateral hemispheres of the brain at Day 3 after ICH, as well as increased the surviving neurons. Finally, the ICH-induced activation of TLR4/NF-κB pathway was suppressed by PN treatment. These findings suggested that PN could be beneficial in the therapeutic strategy for ICH treatment.

microRNA-874 inhibition targeting STAT3 protects the heart from ischemia-reperfusion injury by attenuating cardiomyocyte apoptosis in a mouse model.

MicroRNAs (miRs) were involved in numerous cardiovascular diseases, especially ischemic heart diseases, but the miR changes during cardiac ischemia-reperfusion (I/R) injury following sevoflurane (SEV) preconditioning are still unknown. This study aims to investigate the effect of miR-874 on cardiac I/R injury in mouse models pretreated with SEV. Following establishment of mouse models with myocardial I/R injury, mice were pretreated with SEV. The functional mechanism of miR-874 in I/R injury was explored when miR-874 and the Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway were inhibited. Terminal deoxynucleotidyl transferase (TdT)-mediated dUTP biotin nick-end labeling (TUNEL) staining was used to detect cardiomyocyte apoptosis and dual luciferase reporter gene assay to identify the targeting relationship between miR-874 and STAT3. Expression of the JAK2/STAT3 signaling pathway and apoptosis-related genes was determined. Initially, upregulated miR-874 was observed in I/R mice. Then, miR-874 inhibition improved cardiac function of I/R mice, inhibited cardiomyocyte apoptosis (also shown as decreased Bcl-2 associated X protein B [Bax] and increased B-cell lymphoma-2 [Bcl-2]), and activated the JAK2/STAT3 signaling pathway. STAT3, a target gene of miR-874, was upregulated following miR-874 inhibition. Finally, we also observed that the effect of miR-874 was lost when the JAK2/STAT3 signaling pathway was blocked. The findings indicate miR-874 as a contributory role in cardiac I/R injury, with miR-874 inhibition alleviating cardiac I/R injury in mice following SEV pretreatment by targeting STAT3 through the JAK2/STAT3 signaling pathway.

Astragaloside suppresses tumor necrosis factor receptor-associated factor 5 signaling pathway and alleviates neurodegenerative changes in retinal pigment epithelial cells induced by isoflurane.

Epidemiological studies showed that isoflurane, a general anesthetic widely used in surgery including those for the children, is associated with impairment of neurodevelopment and neurodegenerative diseases, such as Alzheimer's disease (AD) and age-related macular degeneration (AMD), which are related to the accumulation of reactive oxygen species (ROS). Astragaloside (AS) is an antioxidant derivative from a traditional Chinese herbal medicine Astragalus membraneaceus Bunge. In this study, we used retinal pigment epithelial cells, which share plenty of features with neurodegenerative diseases such as AD and AMD to investigate the effect of AS. Cell cycle re-entry and proapoptosis were seen in retinal pigment epithelium (RPE) cells treated with isoflurane, which was alleviated by pretreatment of AS. Further, tumor necrosis factor receptor-associated factor 5 (TRAF5) and downstream nuclear factor-κB (NF-κB) were investigated to elucidate the molecular mechanism underlying protective effect of AS. RPE cells exposed to isoflurane expressed higher TRAF5 and NF-κB than those pretreated with AS, suggesting a critical role of TRAF5 therein. In Morris water maze (MWM) assay, Sprague-Dawley rats pretreated with AS and then exposed to isoflurane spent less time in swimming to the platform, and their TRAF5 expression was significantly lower than those received anesthesia alone. Further studies on the consequence of forced downregulation or upregulation are warranted that may employ cutting-edge technologies such as optogenetics to overcome the difficulties in manipulating expression of TRAF5. Although the link between TRAF5 and neurodegeneration requires more in-depth investigations, our study provide a novel hint on the pathological mechanism of isoflurane and suggest a potential target for eliminating persistent side effect of anesthesia.

Increased diffusion and decreased perfusion in epiphyses of femoral heads detected via intravoxel incoherent motion after closed reduction in children with developmental dysplasia of the hip.

Background Patients with developmental dysplasia of the hip (DDH) may have decreased blood supply to the femoral heads. Finding a non-invasive method to evaluate whether the femoral heads in patients with DDH are ischemic is paramount for orthopedic surgeons. Purpose To identify whether parameters reflecting perfusion and diffusion in intravoxel incoherent motion (IVIM) sequences can be used to assess ischemia in femoral heads in patients with DDH after closed reduction. Material and Methods Twenty-eight patients with DDH who had undergone closed reduction were enrolled. IVIM data were acquired using a 3-T magnetic resonance scanner, regions of interest were placed on the epiphyses; ADCslow, ADCfast, f, and ADCfast×f were measured. A Mann-Whitney U test was performed to compare ADCslow, ADCfast, f, and ADCfast×f between the lesion and control sides. Receiver operating characteristic curves were generated with respective cut-off values. The lesion sides were classified based on the International Hip Dysplasia Institute (IHDI) classification. ADCslow, ADCfast, f, and ADCfast×f were compared among the groups. Results ADCslow was higher and ADCfast, f, and ADCfast×f were lower on the lesion sides ( P = 0.000-0.002). The optimal cut-off value for ADCfast×f, ADCfast, ADCslow, and f were 0.030, 0.626, 0.000251, and 0.636, respectively. Higher IHDI classification scores on the lesion side were associated with lower ADCfast, f, and ADCfast×f, and higher ADCslow values. Conclusion IVIM is a promising method to investigate the perfusion and diffusion of epiphyses of femoral heads.

A functional screening of the kinome identifies the Polo-like kinase 4 as a potential therapeutic target for malignant rhabdoid tumors, and possibly, other embryonal tumors of the brain.

PURPOSE: Malignant rhabdoid tumors (MRTs) are deadly embryonal tumors of the infancy. With poor survival and modest response to available therapies, more effective and less toxic treatments are needed. We hypothesized that a systematic screening of the kinome will reveal kinases that drive rhabdoid tumors and can be targeted by specific inhibitors. METHODS: We individually mutated 160 kinases in a well-characterized rhabdoid tumor cell line (MON) using lentiviral clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9). The kinase that most significantly impaired cell growth was further validated. Its expression was evaluated by microarray gene expression (GE) within 111 pediatric tumors, and functional assays were performed. A small molecule inhibitor was tested in multiple rhabdoid tumor cell lines and its toxicity evaluated in zebrafish larvae. RESULTS: The Polo-like kinase 4 (PLK4) was identified as the kinase that resulted in higher impairment of cell proliferation when mutated by CRISPR/Cas9. PLK4 CRISPR-mutated rhabdoid cells demonstrated significant decrease in proliferation, viability, and survival. GE showed upregulation of PLK4 in rhabdoid tumors and other embryonal tumors of the brain. The PLK4 inhibitor CFI-400945 showed cytotoxic effects on rhabdoid tumor cell lines while sparing non-neoplastic human fibroblasts and developing zebrafish larvae. CONCLUSIONS: Our findings indicate that rhabdoid tumor cell proliferation is highly dependent on PLK4 and suggest that targeting PLK4 with small-molecule inhibitors may hold a novel strategy for the treatment of MRT and possibly other embryonal tumors of the brain. This is the first time that PLK4 has been described as a potential target for both brain and pediatric tumors.

Procalcitonin levels in bloodstream infections caused by different sources and species of bacteria.

OBJECTIVE: The aim of this study was to evaluate procalcitonin (PCT) diagnostic accuracy in discriminating gram-negative (GN) from gram-positive (GP) bloodstream infections and determining the relationship between PCT levels, infection sites, and pathogen types. METHODS: Clinical and laboratory data were collected from patients with blood culture (BC)-positive sepsis between January 2014 and December 2015. PCT levels at different infection sites were compared, as was the presence of GN and GP bloodstream infection. A receiver operating characteristic (ROC) curve was generated to assess diagnostic accuracy. RESULTS: Of the 486 monomicrobial BCs, 254 (52.26%) were positive for GN bacteria (GNB), and 202 (42.18%) for GP bacteria (GPB). Median PCT levels were higher in BCs positive for GN (2.42ng/ml, IQR: 0.38-15.52) than in those positive for GPB (0.49ng/ml, IQR: 0.13-5.89) (P<0.001). In the ROC analysis to differentiate between GNB and GPB, the area under the curve was 0.628 (95% CI: 0.576-0.679). When the cutoffs for PCT were 10.335 and 15.000ng/ml, the specificity of GNB infection was 80.2% and 84.2%, respectively. PCT levels caused by GNB differed between Escherichia coli and Acinetobacter baumanni/Burkholderia cepacia, Klebsiella pneumonia and Acinetobacter baumanni. PCT levels caused by GPB differed between Staphylococcus epidermidis/Staphylococcus aureus and Staphylococcus hominis/Staphylococcus haemolyticus, Enterococcus faecium and Enterococcus faecalis/S.hominis/S. haemolyticus. Among patients with known infection sites, there were statistical differences in PCT levels between abdominal infection and pneumonia/infective endocarditis, urinary tract infection and pneumonia/catheter-related infection/infective endocarditis. CONCLUSION: PCT can distinguish between GNB and GPB infection, as well as between different bacterial species and infection sites.

Water-soluble Manganese and Iron Mesotetrakis(carboxyl)porphyrin: DNA Binding, Oxidative Cleavage, and Cytotoxic Activities.

Two new water-soluble metal carboxyl porphyrins, manganese (III) meso-tetrakis (carboxyl) porphyrin and iron (III) meso-tetrakis (carboxyl) porphyrin, were synthesized and characterized. Their interactions with ct-DNA were investigated by UV-Vis titration, fluorescence spectra, viscosity measurement and CD spectra. The results showed they can strongly bind to ct-DNA via outside binding mode. Electrophoresis experiments revealed that both complexes can cleave pBR322 DNA efficiently in the presence of hydrogen peroxide, albeit 2-Mn exhibited a little higher efficiency. The inhibitor tests suggest the oxidative DNA cleavage by these two complexes may involve hydroxyl radical active intermediates. Notably, 2-Mn exhibited considerable photocytotoxicity against Hep G2 cell via triggering a significant generation of ROS and causing disruption of MMP after irradiation.

Ectopic expression of a phytochrome B gene from Chinese cabbage (Brassica rapa L. ssp. pekinensis) in Arabidopsis thaliana promotes seedling de-etiolation, dwarfing in mature plants, and delayed flowering.

Phytochrome B (phyB) is an essential red light receptor that predominantly mediates seedling de-etiolation, shade-avoidance response, and flowering time. In this study, we isolate a full-length cDNA of PHYB, designated BrPHYB, from Chinese cabbage (Brassica rapa L. ssp. pekinensis), and we find that BrphyB protein has high amino acid sequence similarity and the closest evolutionary relationship to Arabidopsis thaliana phyB (i.e., AtphyB). Quantitative reverse transcription (RT)-PCR results indicate that the BrPHYB gene is ubiquitously expressed in different tissues under all light conditions. Constitutive expression of the BrPHYB gene in A. thaliana significantly enhances seedling de-etiolation under red- and white-light conditions, and causes dwarf stature in mature plants. Unexpectedly, overexpression of BrPHYB in transgenic A. thaliana resulted in reduced expression of gibberellins biosynthesis genes and delayed flowering under short-day conditions, whereas AtPHYB overexpression caused enhanced expression of FLOWERING LOCUS T and earlier flowering. Our results suggest that BrphyB might play an important role in regulating the development of Chinese cabbage. BrphyB and AtphyB have conserved functions during de-etiolation and vegetative plant growth and divergent functions in the regulation of flowering time.

Lung ultrasonography for the diagnosis of 11 patients with acute respiratory distress syndrome due to bird flu H7N9 infection.

BACKGROUND: A novel reassortant avian-origin influenza A (H7N9) virus was found to infect three Chinese residents, the first H7N9 infection in humans in Asia. Chest computed tomography (CT) for acute respiratory distress syndrome (ARDS) diagnosis is not only expensive but also exposes patients to radiation and might cause patients to be at risk of infection during transportation; in addition, chest radiography cannot be used to monitor the lung repeatedly in real time. Therefore, the routine use of bedside lung ultrasonography for critically ill patients with ARDS is especially valuable. OBJECTIVES: The aim of this study was to evaluate the application of ultrasound for lung examination in patients with ARDS. METHODS: Eleven patients infected with H7N9 avian influenza who developed ARDS were diagnosed by lung ultrasonography. RESULTS: Six patients who had severe ARDS showed a diffuse comet tail sign or a consolidation score ≥ 7 and a lung ultrasound score ≥ 20 points. A diffuse comet tail sign or a consolidation score ≤ 6 and a lung ultrasound score < 25 were observed in four patients. One patient showed a diffuse comet tail sign or consolidation area in four lung areas, with an ultrasound score of 14. Among all 11 patients studied, 6 patients had thoracic puncture and drainage of pleural effusion and 2 patients had pneumothorax puncture drainage. CONCLUSIONS: Lung ultrasound could be useful for monitoring ARDS caused by the influenza virus A H7N9 strain in clinical applications.

Synthesis of scutellarein derivatives to increase biological activity and water solubility.

In order to improve the biological activity and water solubility of scutellarin (1), some derivatives of its main metabolite (scutellarein) were designed and synthesized. All the compounds were tested for their thrombin inhibition activity through the analyzation of thrombin time (TT), activated partial thromboplastin time (APTT), prothrombin time (PT) and fibrinogen (FIB). Their antioxidant activities were assessed by measuring their scavenging capacities toward 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and the ability to protect PC12 cells against H2O2-induced cytotoxicity, their water solubility were also assessed by ultraviolet (UV) spectrophotometer. The results showed that compound 8b demonstrated stronger anticoagulant and antioxidant activity, better water solubility compared with scutellarein (2), which warrants it as a promising agent for the treatment of ischemic cerebrovascular disease.

A new and practical synthetic method for the synthesis of 6-O-methyl-scutellarein: one metabolite of scutellarin in vivo.

Scutellarin (1) has been used for the treatment of angina pectoris, cerebral infarction and coronary heart disease with a large market share in China. Pharmacokinetic studies on scutellarin showed that scutellarin (1) is readily converted into its metabolites in vivo. In this paper, a new and practical synthetic method for the synthesis of 6-O-methyl-scutellarein (3) (one metabolite of scutellarin in vivo) is reported. The benzyl bromide was firstly used to selectively replace the acetyl group at C-7 in 7, and was then used to protect the hydroxy groups at C-4' in 10, 6-O-methyl-scutellarein (3) is obtained in high yield through these methods.

A new and efficient synthesis of 6-O-methylscutellarein, the major metabolite of the natural medicine scutellarin.

In this paper, a new and efficient synthesis of 6-O-methylscutellarein (3), the major metabolite of the natural medicine scutellarin, is reported. Two hydroxyl groups at C-4' and C-7 in 2 were selectively protected by chloromethyl methyl ether after the reaction conditions were optimized, then 6-O-methyl-scutellarein (3) was produced in high yield after methylation of the hydroxyl group at C-6 and subsequent deprotection of the two methyl ether groups.

P2X4 receptor in the dorsal horn partially contributes to brain-derived neurotrophic factor oversecretion and toll-like receptor-4 receptor activation associated with bone cancer pain.

Previous studies have suggested that the microglial P2X7 purinoceptor is involved in the release of tumor necrosis factor-α (TNFα) following activation of toll-like receptor-4 (TLR4), which is associated with nociceptive behavior. In addition, this progress is evoked by the activation of the P2X4 purinoceptor (P2X4R). Although P2X4R is also localized within spinal microglia in the dorsal horn, little is known about its role in cancer-induced bone pain (CIBP), which is in some ways unique. With the present rat model of CIBP, we demonstrate a critical role of the microglial P2X4R in the enhanced nociceptive transmission, which is associated with TLR4 activation and secretion of brain-derived neurotrophic factor (BDNF) and TNFα in the dorsal horn. We assessed mechanical threshold and spontaneous pain of CIBP rats. Moreover, P2X4R small interfering RNA (siRNA) was administered intrathecally, and real-time PCR, Western blots, immunofluorescence histochemistry, and ELISA were used to detect the expression of P2X4R, TLR4, OX-42, phosphorylated-p38 MAPK (p-p38), BDNF, and TNFα. Compared with controls, intrathecal injection of P2X4R siRNA could prevent nociceptive behavior induced by ATP plus lipopolysaccharide and CIBP and reduce the expression of P2X4R, TLR4, p-p38, BDNF, and TNFα. In addition, the increase of BDNF protein in rat microglial cells depended on P2X4 receptor signaling, which is partially associated with TLR4 activation. The ability of microglial P2X4R to activate TLR4 in spinal cord leading to behavioral hypersensitivity and oversecretion of BDNF could provide an opportunity for the prevention and treatment of CIBP.

Synthetic TAL effectors for targeted enhancement of transgene expression in plants.

Transcription activator-like effectors (TALEs), secreted by the pathogenic bacteria Xanthomonas, specifically activate expression of targeted genes in plants. Here, we designed synthetic TALEs that bind to the flanking regions of the TATA-box motif on the CaMV 35S promoter for the purpose of understanding the engineerable 'hot-spots' for increasing transgene expression. We demonstrated that transient expression of de novo-engineered TALEs using agroinfiltration could significantly increase reporter gene expression in stable transgenic tobacco expressing the orange fluorescent protein reporter gene pporRFP under the control of synthetic inducible, minimal or full-length 35S promoters. Moreover, the additive effects of a combination of two different synthetic TALEs could significantly enhance the activation effects of TALEs on reporter gene expression more than when each TALE was used individually. We also studied the effects of the C-terminal domain and the activation domain of synthetic TALEs, as well as the best 'hot-spots' on the 35S promoter on targeted transgene activation. Furthermore, TALE activation of the Arabidopsis MYB transcription factor AtPAP1 (PRODUCTION OF ANTHOCYANIN PIGMENT 1) in stable transgenic tobacco gave rise to a dark purple colour on infiltrated leaves when driven by four copies of cis-regulatory elements of pathogenesis-related gene (PR1) with enhancer motifs B and A1 from the 35S promoter. These results provide novel insights into the potential applications of synthetic TALEs for targeted gene activation of transgenes in plants.

Poly[(µ3-3,5-diisopropyl-4H-1,2,4-triazolato-κ(3) N:N':N'')silver(I)].

In the polymeric title compound, [Ag(C8H14N3)] n , the Ag(I) cation is coordinated by three N atoms from three 3,5-diisopropyl-1,2,4-triazolate anions in a T-shaped geometry. The Ag(I) cation deviates from the coordination plane by 0.014 (1) Šand the N-Ag-N bond angles are 96.85 (11), 97.72 (10) and 165.39 (12)°. The triazolate anion bridges three Ag(I) cations, forming a three-dimensional polymeric network.

[The profile of IGF2R gene expression and H3 histone modifications in replicative cell senescence].

OBJECTIVE: To study the profile of IGF2R expression and histone modifications in replicative cell senescence. METHODS: The changes of biological characteristics of young human pulmonary fibroblast (HPF) cells [at population doubling level (PDL) 23] and aging HPF cells (at PDL50) were observed and real-time quantitative PCR was utilized to investigate human IGF2R gene expressions profile during the process of cellular aging (at different PDL). Then chromatinimmunoprecipitation-real time quantitative PCR (CHIP-QPCR) methods were conducted to analyze histone modifications of the regions around the transcriptional start site of IGF2R (H3-Ac, H3K9-tri-Me, H3K9-Ac and H3K4-tri-Me). RESULTS: In contrast to young cells, the aging cells were bigger and less proliferative, their cell cycles arrest, and aging specific beta-galactosidase staining was positive. IGF2R gene expression was in positive correlation with PDL. H3-Ac, H3K9-Ac and H3K4-tri-Me were dominant in the upstream region (-0.6 kb) to the downstream region (+1.2 kb) of transcriptional start site (TSS). While in the downstream of TSS from +1.6 kb to +4.0 kb, H3K9-Ac was declined and H3K9-tri-Me was elevated in turn, but H3K4-tri-Me still prevailed in these areas. CONCLUSION: IGF2R is related to cell replicative senescence and its gene expression is regulated by histone modification of H3. Therefore, epigenetics may play a role in cell senescence.

Synthesis and structure-activity relationship analysis of caffeic acid amides as selective matrix metalloproteinase inhibitors.

Four series of acid amides were synthesized, and through measurement using a fluorogenic substrate assay with human recombinant MMP-1, MMP-2 and MMP-9, compound 3f showed considerable inhibitory activities against MMP-2, MMP-9 and the best selectivity over MMP-1. Preliminary structure-activity relationship analysis indicated that caffeic acid amides with electron-donating groups at para-position of amino phenyl group showed better inhibitory activities and selectivity than those with electron-withdrawing groups, and the presence of adjacent dihydroxy in the caffeoyl group was very important for the MMP-2 and MMP-9 inhibitory activities.