A novel dual-emission fluorescent probe for the simultaneous detection of H2S and GSH

A novel chlorinated coumarin–malononitrile fluorescent probe was synthesized for the simultaneous detection of H₂S and GSH from different emission channels.

On the size and velocity distribution of cosmic dust particles entering the atmosphere

The size and velocity distribution of cosmic dust particles entering the Earth's atmosphere is uncertain. Here we show that the relative concentrations of metal atoms in the upper mesosphere, and the surface accretion rate of cosmic spherules, provide sensitive probes of this distribution. Three cosmic dust models are selected as case studies: two are astronomical models, the first constrained by infrared observations of the Zodiacal Dust Cloud and the second by radar observations of meteor head echoes; the third model is based on measurements made with a spaceborne dust detector. For each model, a Monte Carlo sampling method combined with a chemical ablation model is used to predict the ablation rates of Na, K, Fe, Mg, and Ca above 60 km and cosmic spherule production rate. It appears that a significant fraction of the cosmic dust consists of small (<5 µg) and slow (<15 km s-1) particles.

The near-global mesospheric potassium layer: Observations and modeling

The meteoric metal layers act as unique tracers of chemistry and dynamics in the upper atmosphere. Existing lidar studies from a few locations show that K exhibits a semiannual seasonality (winter and summer maxima), quite unlike the annual seasonality (winter maximum and summer minimum) seen with Na and Fe. This work uses spaceborne observations made with the Optical Spectrograph and InfraRed Imager System instrument on the Odin satellite to retrieve the near-global K layer for the first time. The satellite data (2004 to mid-2013) are used to validate the implementation of a recently proposed potassium chemistry scheme in a whole atmosphere chemistry climate model, which provides a chemical basis for this semiannual seasonal behavior. The satellite and model data show that this semiannual seasonality is near global in extent, with the strongest variation at middle and high latitudes. The column abundance, centroid layer height, and root-mean-square width of the K layer are consistent with the limited available lidar record. The K data set is then used to investigate the impact of polar mesospheric clouds on the metal layers at high latitudes during summer. Finally, the occurrence frequency of sporadic K layers and their possible link to sporadic E layers are examined.

Growth in stratospheric chlorine from short-lived chemicals not controlled by the Montreal Protocol

We have developed a chemical mechanism describing the tropospheric degradation of chlorine containing very short-lived substances (VSLS). The scheme was included in a global atmospheric model and used to quantify the stratospheric injection of chlorine from anthropogenic VSLS ( ClyVSLS) between 2005 and 2013. By constraining the model with surface measurements of chloroform (CHCl₃), dichloromethane (CH₂Cl₂), tetrachloroethene (C₂Cl₄), trichloroethene (C₂HCl₃), and 1,2-dichloroethane (CH₂ClCH₂Cl), we infer a 2013 ClyVSLS mixing ratio of 123 parts per trillion (ppt). Stratospheric injection of source gases dominates this supply, accounting for ∼83% of the total. The remainder comes from VSLS-derived organic products, phosgene (COCl₂, 7%) and formyl chloride (CHClO, 2%), and also hydrogen chloride (HCl, 8%). Stratospheric ClyVSLS increased by ∼52% between 2005 and 2013, with a mean growth rate of 3.7 ppt Cl/yr. This increase is due to recent and ongoing growth in anthropogenic CH₂Cl₂-the most abundant chlorinated VSLS not controlled by the Montreal Protocol.

The decreased expression of protease-activated receptor 4 in esophageal squamous carcinoma

Protease-activated receptors (PARs) are a unique family of G-protein coupled receptors. PAR4, a member of PARs family, was reported to be related to the development of cancers. Whether PAR4 plays a role in the progress of esophageal squamous cancer is unknown. In this study, differential expression of PAR4 in esophageal squamous cancer was measured by real-time PCR (n = 28), western blot and tissue microarrays (n = 78). The results showed that PAR4 expression was remarkably decreased in esophageal squamous cancer tissues compared with the matched noncancerous tissues, especially in low differentiation and positive distant metastasis carcinoma tissues. Furthermore, the methylation level of PAR4 promoter in esophageal cancer cells and normal epithelial cells was determined. Human esophageal cancer cells TE-1 displayed significant hypermethylation of 19 CpG sites, but pronounced hypomethylation of the sites in esophageal epithelial cells HEEpiC. The results suggested that down-regulation expression of PAR4 occurs frequently in esophageal squamous cancers, and the loss of PAR4 expression may partly result from hypermethylation of the PAR4 promoter. That PAR4 expression difference in tumor progression possibly makes PAR4 become a molecular mark of tumor diagnosis.

Quantifying the ozone and ultraviolet benefits already achieved by the Montreal Protocol

Chlorine- and bromine-containing ozone-depleting substances (ODSs) are controlled by the 1987 Montreal Protocol. In consequence, atmospheric equivalent chlorine peaked in 1993 and has been declining slowly since then. Consistent with this, models project a gradual increase in stratospheric ozone with the Antarctic ozone hole expected to disappear by ∼2050. However, we show that by 2013 the Montreal Protocol had already achieved significant benefits for the ozone layer. Using a 3D atmospheric chemistry transport model, we demonstrate that much larger ozone depletion than observed has been avoided by the protocol, with beneficial impacts on surface ultraviolet. A deep Arctic ozone hole, with column values <120 DU, would have occurred given meteorological conditions in 2011. The Antarctic ozone hole would have grown in size by 40% by 2013, with enhanced loss at subpolar latitudes. The decline over northern hemisphere middle latitudes would have continued, more than doubling to ∼15% by 2013.

Ozone-depleting substances have been controlled by the 1987 Montreal Protocol, ensuring atmospheric concentrations are now in decline. Here, the authors use a 3D model and suggest that these controls have already had significant benefits, with much larger ozone depletion than previously thought avoided by the protocol.

Diurnal variation of the potassium layer in the upper atmosphere

Measurements of the diurnal cycle of potassium (K) atoms between 80 and 110 km have been made during October (for the years 2004-2011) using a Doppler lidar at Kühlungsborn, Germany (54.1°N, 11.7°E). A pronounced diurnal variation is observed in the K number density, which is explored by using a detailed description of the neutral and ionized chemistry of K in a three-dimensional chemistry climate model. The model captures both the amplitude and phase of the diurnal and semidiurnal variability of the layer, although the peak diurnal amplitude around 90 km is overestimated. The model shows that the total potassium density (≈ K + K⁺ + KHCO₃) exhibits little diurnal variation at each altitude, and the diurnal variations are largely driven by photochemical conversion between these reservoir species. In contrast, tidally driven vertical transport has a small effect at this midlatitude location, and diurnal fluctuations in temperature are of little significance because they are small and the chemistry of K is relatively temperature independent.

Fibronectin chorused cohesion between endothelial progenitor cells and mesenchymal stem cells of mouse bone marrow

Endothelial progenitor cells (EPCs) could function as niche cells to promote self&mdash;renewal of mesenchymal stem cells (MSCs) in the mouse bone marrow. Cohesion was the basis of the two cells to display their biological functions to each other. In this study, we investigated the mechanism of cohesion between MSCs and EPCs. And demonstrated that fibronectin (FN) in EPCs activated the integrin &#945;5&#946;1 of MSCs and further mediated cell-cell cohesion. Integrin &#945;5&#946;1 and its FN ligand played critical roles not only in single&mdash;cell line adhesion, but also in adhesion between stem and niche cells. This novel finding is important to understand the cross&mdash;talk between MSCs and their niche cells.

Revisiting the hemispheric asymmetry in midlatitude ozone changes following the Mount Pinatubo eruption: A 3-D model study

Following the eruption of Mount Pinatubo, satellite and in situ measurements showed a large enhancement in stratospheric aerosol in both hemispheres, but significant midlatitude column O₃ depletion was observed only in the north. We use a three-dimensional chemical transport model to determine the mechanisms behind this hemispheric asymmetry. The model, forced by European Centre for Medium-Range Weather Forecasts ERA-Interim reanalyses and updated aerosol surface area density, successfully simulates observed large column NO₂ decreases and the different extents of ozone depletion in the two hemispheres. The chemical ozone loss is similar in the Northern (NH) and Southern Hemispheres (SH), but the contrasting role of dynamics increases the depletion in the NH and decreases it in the SH. The relevant SH dynamics are not captured as well by earlier ERA-40 reanalyses. Overall, the smaller SH column O₃ depletion can be attributed to dynamical variability and smaller SH background lower stratosphere O₃ concentrations.

Generation of Foxo3-targeted Mice by Injection of mRNAs Encoding Transcription Activator-like Effector Nucleases (TALENs) into Zygotes

In this study, for exploring the mechanism of forkhead box O3(Foxo3) participating in regulation of the activation of primordial oocytes, Foxo3-targeted mice were generated by injection of mRNAs encoding transcription activator-like effector nucleases (TALENs) into mouse zygotes. The TALEN sites were designed with high conservative homologous region among pig, bovine, buffalo and mouse by commercial bio-companies. The TALENs mutagenic non-homologous end-joining (NHEJ) repair activity were determined to be 31.3% in human embryonic kidney 293T (HEK-293T) cells by dual luciferase reporter assay system. Then, we firstly injected TALEN-mRNAs into the cytoplasm of mouse zygotes by micromanipulation, and four of 48 mouse blastocysts were identified as mutation by sequencing. Subsequently, by the method of TALEN-mRNAs injected into the zygotes with pronucleus micromanipulation technique, we obtained seven Foxo3 mutants of 20 FVB/NJ backgrounds mice which were Foxo3-independent alleles with frameshift and deletion mutations. It was very interesting that all seven were heterozygous mutants (Foxo3(-/+) ), and the gene mutagenesis rates of the mice reached 35%. The five Foxo3 mutant females were all infertile in the following 6 months after birth. The histological examination results showed that there were rare primordial follicles and primary follicles in the ovary of Foxo3 mutant compared to that of wide-type female mice. Moreover, one of two mutant males was subfertile and another was fertile normally. Those results suggested that the mutant of Foxo3 severely affected the fertile ability of female and perhaps male in some degree; furthermore, an even more efficient TALENs-based gene mutation method has been established to be poised to revolutionize the study of mouse and other species genetics.

miR-367 promotes epithelial-to-mesenchymal transition and invasion of pancreatic ductal adenocarcinoma cells by targeting the Smad7-TGF-β signalling pathway

BACKGROUND

Aberrant Smad7 expression contributes to the invasion and metastasis of pancreatic cancer cells. However, the potential mechanism underlying aberrant Smad7 expression in human pancreatic ductal adenocarcinoma (PDAC) remains largely unknown.

METHODS

Bioinformatic prediction programmes and luciferase reporter assay were used to identify microRNAs regulating Smad7. The association between miR-367 expression and the overall survival of PDAC patients was evaluated by Kaplan-Meier analysis. The effects of miR-367 and Smad7 on the invasion and metastasis of pancreatic cancer cells were investigated both in vitro and in vivo.

RESULTS

We found that miR-367 downregulated Smad7 expression by directly targeting its 3'-UTR in human pancreatic cancer cells. High level of miR-367 expression correlated with poor prognosis of PDAC patients. Functional studies showed that miR-367 promoted pancreatic cancer invasion in vitro and metastasis in vivo through downregulating Smad7. In addition, we showed that miR-367 promoted epithelial-to-mesenchymal transition by increasing transforming growth factor-β (TGF-β)-induced transcriptional activity.

CONCLUSIONS

The present study identified and characterised a signalling pathway, the miR-367/Smad7-TGF-β pathway, which is involved in the invasion and metastasis of pancreatic cancer cells. Our results suggest that miR-367 may be a promising therapeutic target for the treatment of human pancreatic cancer.

Everolimus plus exemestane for hormone-receptor-positive, human epidermal growth factor receptor-2-negative advanced breast cancer: overall survival results from BOLERO-2†

BACKGROUND

The BOLERO-2 study previously demonstrated that adding everolimus (EVE) to exemestane (EXE) significantly improved progression-free survival (PFS) by more than twofold in patients with hormone-receptor-positive (HR(+)), HER2-negative advanced breast cancer that recurred or progressed during/after treatment with nonsteroidal aromatase inhibitors (NSAIs). The overall survival (OS) analysis is presented here.

PATIENTS AND METHODS

BOLERO-2 is a phase III, double-blind, randomized international trial comparing EVE 10 mg/day plus EXE 25 mg/day versus placebo (PBO) + EXE 25 mg/day in postmenopausal women with HR(+) advanced breast cancer with prior exposure to NSAIs. The primary end point was PFS by local investigator assessment; OS was a key secondary end point.

RESULTS

At the time of data cutoff (3 October 2013), 410 deaths had occurred and 13 patients remained on treatment. Median OS in patients receiving EVE + EXE was 31.0 months [95% confidence interval (CI) 28.0-34.6 months] compared with 26.6 months (95% CI 22.6-33.1 months) in patients receiving PBO + EXE (hazard ratio = 0.89; 95% CI 0.73-1.10; log-rank P = 0.14). Poststudy treatments were received by 84% of patients in the EVE + EXE arm versus 90% of patients in the PBO + EXE arm. Types of poststudy therapies were balanced across arms, except for chemotherapy (53% EVE + EXE versus 63% PBO + EXE). No new safety concerns were identified.

CONCLUSIONS

In BOLERO-2, adding EVE to EXE did not confer a statistically significant improvement in the secondary end point OS despite producing a clinically meaningful and statistically significant improvement in the primary end point, PFS (4.6-months prolongation in median PFS; P < 0.0001). Ongoing translational research should further refine the benefit of mTOR inhibition and related pathways in this treatment setting.

TRIAL REGISTRATION NUMBER

NCT00863655.

Radar detectability studies of slow and small Zodiacal Dust Cloud Particles: I. The case of Arecibo 430 MHz meteor head echo observations

Recent model development of the Zodiacal Dust Cloud (ZDC) model (Nesvorný et al. 2010, 2011b) argue that the incoming flux of meteoric material into the Earth's upper atmosphere is mostly undetected by radars because they cannot detect small extraterrestrial particles entering the atmosphere at low velocities due to the relatively small production of electrons. In this paper we present a new methodology utilizing meteor head echo radar observations that aims to constrain the ZDC physical model by ground-based measurements. In particular, for this work, we focus on Arecibo 430 MHz observations since this is the most sensitive radar utilized for this type of observations to date. For this, we integrate and employ existing comprehensive models of meteoroid ablation, ionization and radar detection to enable accurate interpretation of radar observations and show that reasonable agreement in the hourly rates is found between model predictions and Arecibo observations when: 1) we invoke the lower limit of the model predicted flux (~16 t/d) and 2) we estimate the ionization probability of ablating metal atoms using laboratory measurements of the ionization cross sections of high speed metal atom beams, resulting in values up to two orders of magnitude lower than the extensively utilized figure reported by Jones (1997) for low speeds meteors. However, even at this lower limit the model over predicts the slow portion of the Arecibo radial velocity distributions by a factor of 3, suggesting the model requires some revision.

WAVE3 promotes epithelial-mesenchymal transition of gastric cancer through upregulation of Snail

WAVE3, an actin cytoskeleton remodeling protein overexpressed in many kinds of cancers, has been associated with a lot of metastatic diseases. However, the role and mechanisms of the high expression of WAVE3 in human gastric cancer has not been fully elucidated. Here we demonstrated that WAVE3 was expressed in all six kinds of gastric-cancer cell lines: BGC-823, SGC-7901, AGS, MGC803, MKN28 and MKN45. Furthermore, a correlation was found between aggressiveness of these cell lines and expression of WAVE3. Next, we investigated the role of WAVE3 in SGC-7901 cells and found that upregulating WAVE3 could promote the migration, invasion and proliferation of SGC-7901 cells in vitro. It has been reported that WAVE3 could induce cancer invasion and metastasis by participating epithelial-mesenchymal transition (EMT). However, the mechanisms are not entirely clear. In this study we showed that elevated WAVE3 levels could induce EMT in SGC-7901 cells by dampening the expression of E-cadherin while increasing the expression of vimentin. Elevated WAVE3 levels could also improve the expression of transcription factor Snail. In addition, downregulating Snail could particularly reduce EMT and the metastasis, invasion and proliferation activity in SGC-7901 cells elevated by overexpression of WAVE3. Taken together, we demonstrated that WAVE3 promoted gastric-cancer-cells migration and invasion by taking part in EMT via upregulation of Snail. WAVE3 could be a useful target for gastric-cancer prevention and therapy.

High serum microRNA-335 level predicts aggressive tumor progression and unfavorable prognosis in pediatric acute myeloid leukemia

PURPOSE

MiRNA expression profiles previously showed the higher expression of microRNA(miR)-335 in bone marrow samples of pediatric acute myeloid leukemia (AML) patients than normal controls. Our aim was to investigate associations of miR-335 expression with tumor progression and prognosis in pediatric AML.

METHODS

Real-time quantitative PCR was performed to detect the expression of miR-335 in bone marrow mononuclear cells and serum obtained from patients with pediatric AML and healthy controls.

RESULTS

Expression levels of miR-335 in the bone marrow and serum of pediatric AML patients were both significantly higher than those in normal controls (both P < 0.001). Then, high serum miR-335 level occurred more frequently in French-American-British classification subtype M7 subtype than in other subtypes (P = 0.03). The expression of serum miR-335 in pediatric AML patients with unfavorable karyotypes was also significantly higher than those in intermediate and favorable groups (P = 0.008). Moreover, high serum miR-335 level was markedly associated with shorter relapse-free and overall survivals (both P < 0.001) of patients with pediatric AML. Furthermore, the multivariate analysis identified the serum miR-335 and cytogenetics risk as independent prognostic factors for both relapse-free and overall survivals. More importantly, the prognostic relevance of serum miR-335 expression was more obvious in the subgroup of patients with intermediate-risk cytogenetics.

CONCLUSION

Our data offer the convincing evidence for the first time that serum miR-335 level may be markedly and consistently increased in pediatric AML patients. Serum miR-335 may serve as a promising marker for monitoring the progression and predicting the clinical outcome of patients with this disease.