Unusual Electronic Structures of an Electron Transfer Series of [Cr(μ-η1 : η1 -N2 )Cr]0/1+/2

In dinitrogen (N2 ) fixation chemistry, bimetallic end-on bridging N2 complexes M(μ-η1  : η1 -N2 )M can split N2 into terminal nitrides and hence attract great attention. To date, only 4d and 5d transition complexes, but none of 3d counterparts, could realize such a transformation. Likewise, complexes {[Cp*Cr(dmpe)]2 (μ-N2 )}0/1+/2+ (1-3) are incapable to cleave N2 , in contrast to their Mo congeners. Remarkably, cross this series the N-N bond length of the N2 ligand and the N-N stretching frequency exhibit unprecedented nonmonotonic variations, and complexes 1 and 2 in both solid and solution states display rare thermally activated ligand-mediated two-center spin transitions, distinct from discrete dinuclear spin crossovers. In-depth analyses using wave function based ab initio calculations reveal that the Cr-N2 -Cr bonding in complexes 1-3 is distinguished by strong multireference character and cannot be described by solely one electron configuration or Lewis structure, and that all intriguing spectroscopic observations originate in their sophisticate multireference electronic structures. More critical is that such multireference bonding of complexes 1-3 is at least a key factor that contributes to their kinetic inertness toward N2 splitting. The mechanistic understanding is then used to rationalize the disparate reactivity of related 3d M(μ-η1  : η1 -N2 )M complexes compared to their 4d and 5d analogs.

Snapshots of Early-Stage Quantitative N2 Electrophilic Functionalization

Electrophilic functionalization of N₂ moieties in metal dinitrogen complexes typically initiates the catalytic synthesis of N-containing molecules directly from N₂. Despite intensive research in the last six decades, how to efficiently and even quantitatively convert N₂ into diazenido and hydrazido species still poses a great challenge. In this regard, systematic and comprehensive investigations to elucidate the reaction intricacies are of profound significance. Herein, we report a kinetic dissection on the first and second electrophilic functionalization steps of a new Cr⁰-N₂ system with HOTf, MeOTf, and Me₃SiOTf. All reactions pass through fleeting diazenido intermediates and furnish long-lived final hydrazido products, and both steps are quantitative conversions at low temperatures. All of the second-order reaction rates of the first and second transformations were determined as well as the lifetimes of the intervening diazenido species. Based on these findings, we succeeded in large-scale and near-quantitative preparation of all hydrazido species.

Lithium chloride promotes neural functional recovery after local cerebral ischaemia injury in rats through Wnt signalling pathway activation

BACKGROUND

Lithium chloride (LiCl) has a significant neuroprotective effect in cerebral ischaemia. However, to date, there is a paucity of evidence on the role of LiCl in neural restoration after brain ischaemia and the signalling pathways involved remain unclear.

MATERIALS AND METHODS

Therefore, to address this gap, the middle cerebral artery occlusion (MCAO) rat model was used to simulate human ischaemia stroke. Male Sprague-Dawley rats were given MCAO for 90 min followed by reperfusion, and Dickkopf-1 (DKK1, 5.0 μg/kg) was administered half an hour before MCAO. Rats were then treated with hypodermic injection of LiCl (2.0 mmol/kg) twice a day for 1 week. After treatment, cognitive impairment was assessed by the Morris water maze test. Neurological deficit score, 2,3,5-triphenyl tetrazolium chloride staining, brain water content, and histopathology were used to evaluate brain damage. Enzyme-linked immunosorbent assay was used to measure oxidative stress damage and inflammatory cytokines. Apoptosis of the hippocampal neurons was tested by western blot. The key factors of Wnt signalling pathway in the ischaemic penumbra were detected by immunofluorescence staining and quantitative real-time polymerase chain reaction.

RESULTS

Current experimental results showed that LiCl treatment significantly improved the impaired spatial learning and memory ability, suppressed oxidative stress, inflammatory reaction, and neuron apoptosis accompanied by attenuating neuronal damage, which subsequently decreased the brain oedema, infarct volume and neurological deficit. Furthermore, the treatment of LiCl activated Wnt signalling pathway. Interestingly, the aforementioned effects of LiCl treatment were markedly reversed by administration of DKK1, an inhibitor of Wnt signalling pathway.

CONCLUSIONS

These results indicate that LiCl exhibits neuroprotective effects in focal cerebral ischaemia by Wnt signalling pathway activation, and it might have latent clinical application for the prevention and treatment of ischaemic stroke.

[A pedigree study of Loeys-Dietz syndrome type 4 with skeletal deformity related to a novel TGFβ2 mutation]

Objective: Loeys-Dietz syndrome is a rare type of hereditary connective tissue disease. This study was aimed to analyze the clinical characteristics and gene mutations in a family of Loeys-Dietz syndrome with skeletal deformity. Methods: Clinical data of the proband and family members were collected and biochemical measurements and radiological examinations were conducted. Genomic DNA was extracted from peripheral blood of the family members. Whole-exome sequencing was performed to determine the mutation sites in the proband, and Sanger sequencing was applied to verify the candidate mutation in the other family members. Results: The proband is a 34-year-old man with deformities of lower extremities for more than 30 years. Physical examinations showed dolichostenomelia, pes planus, joint laxity and scoliosis. Echocardiography revealed the dilatation of aortic root at the level of the sinuses of Valsalva. A heterozygous missense mutation (c. 220A>C, p.Thr74Pro) in exon 1 of TGFβ2 gene was identified in the proband. The same mutation was detected in his sister and niece with similar clinical features such as deformities of lower extremities and pes planus. This novel mutation has not been reported in ExAC or 1000G and was predicted to be deleterious, supporting a diagnosis of Loeys-Dietz syndrome type 4. Conclusions: Loeys-Dietz syndrome type 4 is caused by TGFβ2 mutations. Skeletal deformity is one of the distinctive features. Genetic testing is helpful for the early diagnosis and differential diagnosis from other connective tissue diseases.

Synthesis of 3,3-Dialkyl-Substituted Isoindolinones Enabled by Nickel-Catalyzed Reductive Dicarbofunctionalization of Enamides

Herein we report the nickel-catalyzed reductive dicarbofunctionalization of 1,1-disubstituted enamides with unactivated alkyl iodides to access the 3,3-dialkyl-substituted isoindolinone frameworks. This tandem cyclization/reductive coupling protocol exhibits broad functional group tolerance under mild conditions. The utilization of commercially accessible chiral Bn-Biox ligand allows excellent enantioselectivities to forge the tetrasubstituted stereocenters.

Jasmonic acid-induced hydrogen sulfide activates MEK1/2 in regulating the redox state of ascorbate in Arabidopsis thaliana leaves

In this paper, we investigated the relationship between hydrogen sulfide (H₂S) and mitogen-activated protein kinase kinase (MEK1/2) in jasmonic acid (JA)-regulated the redox state of ascorbate in the leaves of Arabidopsis thaliana. The results showed that JA significantly enhanced the phosphorylation level of MEK1/2, the production of endogenous H₂S and the ratio of reduced ascorbate (AsA) to dehydroascorbate (DHA) (AsA/DHA) in wild type of A. thaliana (WT). However, there were no obvious effects of JA on above indicators in H₂S synthetic mutant of A. thaliana (MT). H₂S scavenger hypotaurine (HT) markedly reduced JA-induced the phosphorylation level of MEK1/2, AsA/DHA ratio and the production of endogenous H₂S in WT. Application of H₂S donor sodium hydrosulfide (NaHS) to JA-treated MT plants increased above indicators. Application of NaHS to (HT+JA)-treated MT plants did not reverse the effects of HT on above JA-induced indicators. MEK1/2 inhibitor PD98059 decreased JA-induced AsA/DHA ratio and the transcript levels and the activities of ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR) and L-galactono-1,4-lactone dehydrogenase (GalLDH) in WT. However, PD98059 had no effect on JA-induced the production of endogenous H₂S in WT. Compared with Control-MT, there were no obvious effects of JA on the production of endogenous H₂S, AsA/DHA ratio and the transcript levels and activities of above enzymes in MT. However, application of PD98059 reduced above JA-induced indicators except the production of endogenous H₂S and DHA content in MT. Our results suggested that H₂S activated MEK1/2 in JA-regulated AsA/DHA ratio in A. thaliana leaves through enzymes in ascorbate metabolism.

Skin resistance to UVB-induced oxidative stress and hyperpigmentation by the topical use of Lactobacillus helveticus NS8-fermented milk supernatant

AIMS

In this study, we investigated the preventive properties of the supernatant of Lactobacillus helveticus NS8-fermented milk (NS8-FS) against UV light-induced skin oxidative damage and hyperpigmentation.

METHODS AND RESULTS

NS8-FS exhibited significant radical scavenging activity in tests with ABST⁺ and DPPH scavenging methods, and as well strongly inhibited 3-morpholinosydnonimine (Sin-1)-induced ROS generation in HaCat keratinocytes. Unexpectedly, NS8-FS was found to inhibit melanin production in B16F10 melanoma cells and to exhibit inhibitory effects both to the enzymatic activity of tyrosinase (TYR) and the expression of proteins required for melanin synthesis. In SKH-1 hairless mice, topical application of NS8-FS alleviated UVB-induced skin photodamage, including the improvement of the appearance of epidermal thickness, transepidennal water loss and lipid peroxidation levels. In the tanning guinea pig model, the whitening effect of NS8-FS was demonstrated using Masson-Fontana staining and TYR staining. Furthermore, NS8-FS was shown to stimulate the nuclear translocation and activation of the Nrf2 protein, along with recovery of antioxidant enzyme activities.

CONCLUSION

NS8-FS exhibits the protective capacities against UV light-induced skin oxidative damage and hyperpigmentation.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our findings indicate the potential of cell-free fermented products of lactic acid bacteria in topical photoprotection.

[Ventilator-associated pneumonia among premature infants <34 weeks' gestational age in neonatal intensive care unit in China: a multicenter study]

Objective: To investigate the incidence and pathogen distribution of ventilator-associated pneumonia (VAP) among preterm infants admitted to level Ⅲ neonatal intensive care units (NICU) in China. Method: A prospective study was conducted in 25 level Ⅲ NICU, enrolling all preterm infants <34 weeks gestational age admitted to the participating NICU within the first 7 days of life from May 2015 to April 2016. Chi-square test, t test and Mann-Whitney U test were used for statistical analysis. Result: A total of 7 918 patients were enrolled, within whom 4 623(58.4%) were males. The birth weight was (1 639±415) g and the gestational age was (31.4±2.0) weeks; 4 654(58.8%) infants required non-invasive mechanical ventilation and 2 154(27.2%) required intubation. Of all the mechanically ventilated patients, VAP occurred in 95 patients. The overall VAP rate was 7.0 episodes per 1 000 ventilator days, varying from 0 to 34.4 episodes per 1 000 ventilator days in different centers. The incidence of VAP was 9.6 and 6.0 per 1 000 ventilator days in children's hospitals and maternity-infant hospitals respectively, without significant differences (t=1.002, P=0.327). Gram-negative bacilli (76 strains, 91.6%) were the primary VAP microorganisms, mainly Acinetobacter baumannii (24 strains, 28.9%), Klebsiella pneumonia (23 strains, 27.7%), and Pseudomonas aeruginosa (10 strains, 12.0%). Conclusion: The incidence of VAP in China is similar to that in developed counties, with substantial variability in different NICU settings. More efforts are needed to monitor and evaluate the preventable factors associated with VAP and conduct interventions that could effectively reduce the occurrence of VAP.

Targeting 6-phosphogluconate dehydrogenase in the oxidative PPP sensitizes leukemia cells to antimalarial agent dihydroartemisinin

The oxidative pentose phosphate pathway (PPP) is crucial for cancer cell metabolism and tumor growth. We recently reported that targeting a key oxidative PPP enzyme, 6-phosphogluconate dehydrogenase (6PGD), using our novel small molecule 6PGD inhibitors Physcion and its derivative S3, shows anti-cancer effects. Notably, humans with genetic deficiency of either 6PGD or another oxidative PPP enzyme, glucose-6-phosphate dehydrogenase (G6PD), exhibit non-immune hemolytic anemia upon exposure to aspirin and various anti-malarial drugs. Inspired by these clinical observations, we examined the anti-cancer potential of combined treatment with 6PGD inhibitors and anti-malarial drugs. We found that stable knockdown of 6PGD sensitizes leukemia cells to anti-malarial agent dihydroartemisinin (DHA). Combined treatment with DHA and Physcion activates AMP-activated protein kinase, leading to synergistic inhibition of human leukemia cell viability. Moreover, our combined therapy synergistically attenuates tumor growth in xenograft nude mice injected with human K562 leukemia cells and cell viability of primary leukemia cells from human patients, but shows minimal toxicity to normal hematopoietic cells in mice as well as red blood cells and mononucleocytes from healthy human donors. Our findings reveal the potential for combined therapy using optimized doses of Physcion and DHA as a novel anti-leukemia treatment without inducing hemolysis.

[Acupoint selection: a key factor to influence the compatibility of acupoint]

In this paper, from the concept of acupoint compatibility, it is proposed that acupoint selection is a key factor to influence the compatibility of acupoint, and the nature of acupoint is closely related with the location and dominant meridian of acupoints. Acupoint selection according to the location and meridians is the basic method of acupoint compatibility, while acupoint selection based on the syndrome differentiation and the symptoms is the fundamental requirement of acupoint compatibility. Therefore, understanding the nature of acupoint, knowing the method of acupoint compatibility and selecting analogous acupoint that have identical or similar indications are the keys to improve the clinical efficacy.

Topical combined application of dexamethasone, vitamin C, and β-sodium glycerophosphate for healing the extraction socket in rabbits

An osteogenic inducer (OI) consisting of dexamethasone, vitamin C, and β-sodium glycerophosphate has the capacity to induce bone formation in vitro. The aim of this study was to assess the efficacy of the application of this OI on extraction socket healing. The bilateral first mandibular premolars were extracted from 75 New Zealand rabbits. Gelatin sponges carrying OI were implanted into the sockets. Sockets undergoing implantation of gelatin sponges alone were also evaluated, as well as non-implantation sockets. Specimens from each group were evaluated radiographically, histologically, and histomorphometrically using haematoxylin-eosin staining. Results showed earlier new bone formation and higher bone quality and quantity in the OI group compared to the other groups, and the differences were significant at 2, 4, 8, and 12 weeks postoperative. The OI significantly reduced the absorption of alveolar bone in terms of height; however, changes in the width were not significantly different between the three groups (P>0.05). The OI was shown to have a positive effect on healing of the tooth extraction sockets, was inexpensive, and was convenient to use during the operational procedure; therefore this could represent a promising implant material for human clinical application.

RhoA/ROCK/PTEN signaling is involved in AT-101-mediated apoptosis in human leukemia cells in vitro and in vivo

R-(-)-gossypol acetic acid (AT-101) is a natural cottonseed product that exhibits anticancer activity. However, the molecular mechanism behind the antileukemic activity of AT-101 has not been well characterized. In this study, we investigated how AT-101 induces apoptosis in human leukemia cells. Exposure to AT-101 significantly increased apoptosis in both human leukemia cell lines and primary human leukemia cells. This increase was accompanied by the activation of caspases, cytochrome c release, Bcl2-associated X protein (Bax) translocation, myeloid cell leukemia-1 (Mcl-1) downregulation, Bcl-2-associated death promoter (Bad) dephosphorylation, Akt inactivation, and RhoA/Rho-associated coiled-coil containing protein kinase 1/phosphatase and tensin homolog (RhoA/ROCK1/PTEN) activation. RhoA, rather than caspase-3 cleavage, mediated the cleavage/activation of ROCK1 that AT-101 induced. Inhibiting RhoA and ROCK1 activation by C3 exoenzyme (C3) and Y27632, respectively, attenuated the ROCK1 cleavage/activation, PTEN activity, Akt inactivation, Mcl-1 downregulation, Bad dephosphorylation, and apoptosis mediated by AT-101. Knocking down ROCK1 expression using a ROCK1-specific siRNA also significantly abrogated AT-101-mediated apoptosis. Constitutively active Akt prevented the AT-101-induced Mcl-1 downregulation, Bad dephosphorylation, and apoptosis. Conversely, AT-101 lethality was potentiated by the phosphatidylinositol 3-kinase inhibitor LY294002. In vivo, the tumor growth inhibition caused by AT-101 was also associated with RhoA/ROCK1/PTEN activation and Akt inactivation in a mouse leukemia xenograft model. Collectively, these findings suggest that AT-101 may preferentially induce apoptosis in leukemia cells by interrupting the RhoA/ROCK1/PTEN pathway, leading to Akt inactivation, Mcl-1 downregulation, Bad dephosphorylation, and Bax translocation, which culminate in mitochondrial injury and apoptosis.

Estimation of birth population-based perinatal-neonatal mortality and preterm rate in China from a regional survey in 2010

Objective:

To estimate birth population-based perinatal-neonatal mortality and preterm rate in China from a regional survey in 2010.

Study design:

Data of total births in 2010 obtained from 151 level I–III hospitals in Huai’an, Jiangsu, were prospectively collected and analyzed.

Results:

From 61 227 birth registries (including 60 986 live births and 241 stillbirths), we derive a birth rate of 11.3‰ (of 5.4 million regional population), a male-to-female ratio of 116:100 and valid data from 60 615 newborns. Mean birth weight (BW) was 3441 ± 491 g with 13.6% macrosomia. Low BW was 2.8% (1691/60 372) with 8.83% mortality. Preterm rate was 3.72% (2239/60 264) with 7.61% mortality. Cesarean section rate was 52.9% (31 964/60 445), multiple pregnancy 1.8% (1088/60 567) and birth defects 6.7‰ (411/61 227). There were 97.4% healthy newborns and 2.2% (1298) requiring hospitalized after birth. The perinatal mortality was 7.7‰ (471/61 227, including 241 stillbirths, 230 early neonatal deaths). The neonatal mortality was 4.4‰ (269/60 986). The main causes of neonatal death were birth asphyxia (24.5%), respiratory diseases (21.5%), prematurity related organ dysfunction (18.5%) and congenital anomalies (7.7%), whereas incidence of congenital heart disease and respiratory distress syndrome was 8.6‰ and 6.1‰, respectively.

Conclusions:

This regional birth population-based data file contains low perinatal-neonatal mortality rates, associated with low proportion of LBW and preterm births, and incidences of major neonatal disease, by which we estimate, in a nationwide perspective, in 16 million annual births, preterm births should be around 800 000, perinatal and neonatal mortality may be 128 000–144 000 and 80 000–96 000, respectively, along with 100 000 respiratory distress syndrome.

Downregulation of Mcl-1 through inhibition of translation contributes to benzyl isothiocyanate-induced cell cycle arrest and apoptosis in human leukemia cells

Benzyl isothiocyanate (BITC) is one of the compounds of ITCs' family that has attracted a great deal of interest because of its ability to exhibit anticancer activity. In this study, we investigated the effects of BITC on cell cycle arrest and apoptosis in human leukemia cell lines, primary leukemia cells, and nude mice Jurkat xenograft. Exposure of Jurkat cells to BITC resulted in dose- and time-dependent increase in apoptosis, caspase activation, cytochrome c release, nuclear apoptosis-inducing factor (AIF) accumulation, Bcl2-associated X protein (Bax) translocation, and myeloid cell leukemia-1 (Mcl-1) downregulation. Treatment with these cells also resulted in cell cycle arrest at the G2/M phase. The G2/M-arrested cells are more sensitive to undergoing Mcl-1 downregulation and apoptosis mediated by BITC. BITC downregulates Mcl-1 expression through inhibition of translation, rather than through a transcriptional, post-translational, or caspase-dependent mechanism. Dephosphorylation of eukaryotic initiation factor 4G could contribute to the inhibition of Mcl-1 translation mediated by BITC. Furthermore, ectopic expression of Mcl-1 substantially attenuates BITC-mediated lethality in these cells, whereas knockdown of Mcl-1 through small interfering RNA significantly enhances BITC-mediated lethality. Finally, administration of BITC markedly inhibited tumor growth and induced apoptosis in Jurkat xenograft model in association with the downregulation of Mcl-1. Taken together, these findings represent a novel mechanism by which agents targeting Mcl-1 potentiate BITC lethality in transformed and primary human leukemia cells and inhibitory activity of tumor growth of Jurkat xenograft model.

MicroRNA-520e suppresses growth of hepatoma cells by targeting the NF-κB-inducing kinase (NIK)

MicroRNAs (miRNAs) are small, non-coding RNAs that can act as oncogenes or tumor suppressor genes in human cancer. Emerging evidence indicates that deregulation of miRNAs contributes to the hepatocarcinogenesis. In the present study, we demonstrated that the levels of miR-520e were dramatically decreased in examined hepatoma cell lines and clinical hepatocellular carcinoma (HCC) tissues. Moreover, we found that DNA hypermethylation in the upstream region of miR-520e resulted in the downregulation of miR-520e. Next, we demonstrated that introduction of miR-520e dramatically suppressed the growth of hepatoma cells in vitro and in vivo, whereas silencing the expression of miR-520e by anti-miR-520e resulted in a promoted cell proliferation, suggesting that miR-520e may be a novel tumor suppressor. Further studies revealed that NF-κB-inducing kinase (NIK) was one of the direct target genes of miR-520e, as miR-520e directly bound to the 3'untranslated region of NIK, which reduced the expression of NIK at the levels of mRNA and protein. Moreover, silencing of NIK was able to inhibit the growth of hepatoma cells, similar to the effect of miR-520e overexpression on growth of hepatoma cells. Meanwhile, the knockdown of NIK expression reversed the enhanced proliferation mediated by anti-miR-520e. In addition, miR-520e significantly decreased the phosphorylation of ERK1/2 (p-ERK1/2) and depressed the transcriptional activity and nuclear translocation of nuclear factor κB (NF-κB) (p65). These results suggest that miR-520e suppresses the growth of hepatoma cells by targeting NIK involving the NIK/p-ERK1/2/NF-κB signaling pathway. Finally, we showed that the intratumoral injection with miR-520e was able to directly repress the growth of hepatoma cells in the nude mice. Thus, our finding provides new insight into the mechanism of hepatocarcinogenesis, indicating a therapeutic potential of miR-520e in the treatment of HCC.

Treatment of Chronic Idiopathic Urticaria with Levamisole: A Multicentre, Randomized, Double-Blind, Controlled Trial

The objective of this study was to evaluate the efficacy of treating chronic idiopathic urticaria (CIU) with levamisole in combination with levocetirizine. This was a multicentre, randomized, double-blind, controlled trial that included 132 patients with active CIU who were treated for 6 weeks with either levocetirizine alone (control group; n = 65) or levamisole plus levocetirizine (treatment group; n = 67). Response to therapy was evaluated by measuring the efficacy rate. After 2 weeks of treatment, there was no significant difference in the efficacy rate between the treatment and control groups (54.84% and 42.37%, respectively). After 6 weeks of treatment, a statistically significant difference in the efficacy rate was observed between the groups (76.27% and 54.39% for the treatment and control groups, respectively). This study demonstrated that a combination of levamisole plus levocetirizine is more effective than levocetirizine alone and potentially provides a new, promising approach to the treatment of CIU.

Estimation of percolation flux from borehole temperature data at Yucca Mountain, Nevada

Temperature data from the unsaturated zone (UZ) at Yucca Mountain are analyzed to estimate percolation-flux rates and overall heat flux. A multilayer, one-dimensional analytical solution is presented for determining percolation flux from temperature data. Case studies have shown that the analytical solution agrees very well with results from the numerical code, TOUGH2. The results of the analysis yield percolation fluxes in the range from 0 to 20 mm/year for most of the deep boreholes. This range is in good agreement with the results of infiltration studies at Yucca Mountain. Percolation flux for the shallower boreholes, however, cannot be accurately determined from temperature data alone because large gas flow in the shallow system alters the temperature profiles. Percolation-flux estimates for boreholes located near or intersecting major faults are significantly higher than those for other boreholes. These estimates may be affected by gas flow in the faults.

[Effect of danshen injection on pulmonary thromboembolism and platelet free radical levels in mice]

The Danshen Injection has been proved good for decreasing platelet malonaldehyde (MDA) levels in pulmonary thromboembolism induced by collagen and adrenaline in mice, as well as increasing the activity of superoxide desmutase (SOD) in platelets, thus providing protection against pulmonary thromboembolism and inhibition of platelet aggregation.