Lead, cadmium, arsenic, and mercury combined exposure disrupted synaptic homeostasis through activating the Snk-SPAR pathway

Lead (Pb), cadmium (Cd), arsenic (As), and mercury (Hg) are among the leading toxic agents detected in the environment, and they have also been detected simultaneously in blood, serum, and urine samples of the general population. Meanwhile early neurologic effects and multiple interactions of Pb, Cd, As, and Hg had been found in children from environmentally polluted area. However, the current studies of these four metals were mostly limited to the interactions between any two metals, whereas the interaction characteristics between any three and four metals were rarely studied. In our study, we firstly explored the characteristics of the neurotoxic interactions among these four elements in nerve cells with factorial designs. The results showed that Pb+Cd+As+Hg co-exposure had a synergistic neurotoxic effect that was more severe than that induced by any two or three metals, when their individual metals were at human environmental exposure (in the blood of U.S. population) relevant levels and below no observed adverse effect levels (NOAELs). Therefore, Pb+Cd+As+Hg co-exposure at human environmental exposure relevant levels were further selected to examine synaptic homeostasis as the cellular and molecular foundation of learning and memory. We reported for the first time that Pb+Cd+As+Hg co-exposure induced dose-dependent decreases of the dendritic lengths and branching, as well as spine density and mature phenotype in primary hippocampal neurons, and the stimulated neurite outgrowths in NGF-differentiated PC12 cells. And the above synaptic homeostasis disruption was associated with serum induced kinase (Snk)-spine associated Rap GTPase activating protein (SPAR) pathway. Our study suggests that human environmental Pb, Cd, As, and Hg co-exposure has the potential to evoke synergistic neurotoxicity even if their individual metals are below NOAELs, which reinforces the need to control and regulate potential sources of metal contamination.

Myocardial late gadolinium enhancement: a head-to-head comparison of motion-corrected balanced steady-state free precession with segmented turbo fast low angle shot

AIM

To evaluate the image quality and diagnostic agreement with a head-to-head comparison of late gadolinium enhancement (LGE) images acquired by the motion-corrected (MOCO) balanced steady-state free precession (bSSFP) phase sensitivity inversion recovery (PSIR) and conventional segmented fast low angle shot (FLASH) PSIR methods^15,16 in a patient cohort with a wide spectrum of cardiovascular disease.

MATERIALS AND METHODS

In 59 consecutive patients, signal-to-noise ratios (SNRs), contrast-to-noise ratios (CNRs) of the normal myocardium (NM), LGE, and blood pool (BP) were pair-wise compared between the two different sequences. A further semi-qualitative score system (graded 1 -4) was used to compare the overall image quality (OIQ). The diagnostic agreement of the two techniques were evaluated by both transmural severity and absolutely quantitative size of LGE.

RESULTS

The SNRs of the NM, LGE, and BP of MOCO bSSFP were 4.8±3.4, 53.6±35.6 and 43.2±29.3, compared with 3.9±3.6 (p=0.126), 27.7±18.5 (p<0.001) and 24.3±13.4 (p<0.001) of FLASH LGE, respectively. The CNRs of LGE to NM, LGE to BP, and BP to NM were 48.3±33.1 versus 23.8±16.7 (p<0.001), 6.5±21.6 versus 3.8±10.8 (p<0.001), and 38.3±27.2 versus 20.3±10.7 (p=0.448), respectively. The OIQ of MOCO bSSFP was higher than that of segmented FLASH (median 4 versus median 3, p<0.001). For quantification of LGE size, there is good agreement and high correlation (r=0.992, p<0.001) between the two methods.

CONCLUSIONS

MOCO bSSFP is a feasible, robust sequence for LGE imaging, especially for patients with arrhythmia and those incapable of breath-holding due to severe heart failure.

Anacardic acid induces cell apoptosis of prostatic cancer through autophagy by ER stress/DAPK3/Akt signaling pathway

Anacardic acid, which is commonly seen in plants of Anacardiaceae, is an important composition of cashew, ginkgo leaf and fruit, and it has been suggested in previous research to show antitumor activity. The main aim of the present study was to evaluate the anticancer effects of anacardic acid on cell apoptosis of prostatic cancer and molecular mechanisms of this phenomenon. In this study we found that anacardic acid inhibited cell proliferation, induced apoptosis and caspase-3/9 activities and Bax protein expression of prostatic cancer. Anacardic acid induced the ER stress inducing factors (BiP, CHOP, p-eIF2α), autophagy, LC3, Beclin-1, Atg 7 and DAPK3 protein expression, and suppressed p-Akt and p-mTOR protein expression of prostatic cancer. Si-CHOP was used to inhibit ER stress in prostatic cancer by anacardic acid, which showed that the cell proliferation was increased, apoptosis, and caspase-3/9 activities and Bax protein expression was suppressed, autophagy, LC3, Beclin-1, Atg 7 and DAPK3 protein expression was reduced, and p-Akt and p-mTOR protein expression was promoted. DAPK3 inhibited p-Akt and p-mTOR protein expression, enhanced the anticancer effects of anacardic acid on prostatic cancer through autophagy. For the first time, the present study showed that anacardic acid induces cell apoptosis of prostatic cancer through autophagy by ER stress/DAPK3/Akt signaling pathway.

Acute rejection after kidney transplantation promotes graft fibrosis with elevated adenosine level in rat

Aims

Chronic allograft nephropathy is a worldwide issue with the major feature of progressive allograft fibrosis, eventually ending with graft loss. Adenosine has been demonstrated to play an important role in process of fibrosis. Our study aimed to investigate the relationship between adenosine and fibrosis in renal allograft acute rejection in rat.

Materials and methods

Wistar rats and SD rats were selected as experimental animals. Our study designed two groups. In the allograft transplantation group, kidneys of Wistar rats were orthotopically transplanted into SD rat recipients, the same species but not genetically identical, to induce acute rejection. Kidney transplantations of SD rats to SD rats which were genetically identical were served as the control. We established rat models and detected a series of indicators. All data were analyzed statistically. P<0.05 was considered statistically significant.

Results

Compared with the control group, levels of adenosine increased significantly in the allograft transplantation group, in which acute rejection was induced (P<0.05). Progressive allograft fibrosis as well as collagen deposition were observed.

Conclusions

These findings suggested that level of adenosine was upregulated in acute rejection after kidney allograft transplantation in rat. Acute rejection may promote renal allograft fibrosis via the adenosine signaling pathways.

Volatile organic compounds emitted by filamentous fungi isolated from flooded homes after Hurricane Sandy show toxicity in a Drosophila bioassay

Superstorm Sandy provided an opportunity to study filamentous fungi (molds) associated with winter storm damage. We collected 36 morphologically distinct fungal isolates from flooded buildings. By combining traditional morphological and cultural characters with an analysis of ITS sequences (the fungal DNA barcode), we identified 24 fungal species that belong to eight genera: Penicillium (11 species), Fusarium (four species), Aspergillus (three species), Trichoderma (two species), and one species each of Metarhizium, Mucor, Pestalotiopsis, and Umbelopsis. Then, we used a Drosophila larval assay to assess possible toxicity of volatile organic compounds (VOCs) emitted by these molds. When cultured in a shared atmosphere with growing cultures of molds isolated after Hurricane Sandy, larval toxicity ranged from 15 to 80%. VOCs from Aspergillus niger 129B were the most toxic yielding 80% mortality to Drosophila after 12 days. The VOCs from Trichoderma longibrachiatum 117, Mucor racemosus 138a, and Metarhizium anisopliae 124 were relatively non-toxigenic. A preliminary analysis of VOCs was conducted using solid-phase microextraction-gas chromatography-mass spectrometry from two of the most toxic, two of the least toxic, and two species of intermediate toxicity. The more toxic molds produced higher concentrations of 1-octen-3-ol, 3-octanone, 3-octanol, 2-octen-1-ol, and 2-nonanone; while the less toxic molds produced more 3-methyl-1-butanol and 2-methyl-1-propanol, or an overall lower amount of volatiles. Our data support the hypothesis that at certain concentrations, some VOCs emitted by indoor molds are toxigenic.

Effect of selective serotonin reuptake inhibitors on expression of 5-HT1AR and neurotransmitters in rats with vascular dementia

5-hydroxytryptamine receptor 1A (5-HT1AR) is closely associated with cognitive functions. Selective serotonin reuptake inhibitors (SSRIs) can protect individuals from brain damage following ischemia/hypoxia. To investigate the function of SSRIs in vascular dementia (VD), we established a rat model of VD, and observed the effect of SSRIs on the expression of 5-HT1AR mRNA and neurotransmitters. Male SD rats (6 months) were randomly assigned into sham, model, and SSRI groups (N = 30). VD was achieved by permanent ligation of the bilateral common carotid artery. Escitalopram, a highly selective 5-HT reabsorption inhibitor, was ip injected into the rats for three consecutive weeks. The Morris water-maze was used to test learning and memory. H&E staining for neuronal injury was conducted on cortical and hippocampal tissues. HPLC was used to determine the levels of dopamine (DA), 5-HT, and norepinephrine (NE). RT-PCR was used to determine expression of 5-HT1AR mRNA. As compared to control rats, model animals demonstrated elongated escape latency, lower platform crossing times, and significant injuries to hippocampal CA1 neurons. This was accompanied by reductions in DA, 5-HT, and NE levels in hippocampal tissues, as well as reduced cortical 5-HT and decreased 5-HT1AR mRNA expression (P < 0.05). Escitalopram treatments reduced escape latency, elevated platform crossing times, improved CA1 neuronal damage, increased DA and 5-HT levels in hippocampal and cortical neurons, as well as elevated expression of 5-HT1AR mRNA (P < 0.05). Therefore, SSRIs may improve cognitive dysfunction of VD rats, possibly by stimulating expression of neurotransmitters and protecting neurons.

Asymptotic Properties of a Mean-Field Model with a Continuous-State-Dependent Switching Process

This work is concerned with a class of mean-field models given by a switching diffusion with a continuous-state-dependent switching process. Focusing on asymptotic properties, the regularity or nonexplosiveness, Feller continuity, and strong Feller continuity are established by means of introducing certain auxiliary processes and by making use of the truncations. Based on these results, exponential ergodicity is obtained under the Foster–Lyapunov drift conditions. By virtue of the coupling methods, the strong ergodicity or uniform ergodicity in the sense of convergence in the variation norm is established for the mean-field model with a Markovian switching process. Besides this, several examples are presented for demonstration and illustration.

Countable-state-space Markov chains with two time scales and applications to queueing systems

Motivated by various applications in queueing systems, this work is devoted to continuous-time Markov chains with countable state spaces that involve both fast-time scale and slow-time scale with the aim of approximating the time-varying queueing systems by their quasistationary counterparts. Under smoothness conditions on the generators, asymptotic expansions of probability vectors and transition probability matrices are constructed. Uniform error bounds are obtained, and then sequences of occupation measures and their functionals are examined. Mean square error estimates of a sequence of occupation measures are obtained; a scaled sequence of functionals of occupation measures is shown to converge to a Gaussian process with zero mean. The representation of the variance of the limit process is also explicitly given. The results obtained are then applied to treat Mt/Mt/1 queues and Markov-modulated fluid buffer models.

Discrete-time singularly perturbed Markov chains: aggregation, occupation measures, and switching diffusion limit

This work is devoted to asymptotic properties of singularly perturbed Markov chains in discrete time. The motivation stems from applications in discrete-time control and optimization problems, manufacturing and production planning, stochastic networks, and communication systems, in which finite-state Markov chains are used to model large-scale and complex systems. To reduce the complexity of the underlying system, the states in each recurrent class are aggregated into a single state. Although the aggregated process may not be Markovian, its continuous-time interpolation converges to a continuous-time Markov chain whose generator is a function determined by the invariant measures of the recurrent states. Sequences of occupation measures are defined. A mean square estimate on a sequence of unscaled occupation measures is obtained. Furthermore, it is proved that a suitably scaled sequence of occupation measures converges to a switching diffusion.

Convergence of a global stochastic optimization algorithm with partial step size restarting

This work develops a class of stochastic global optimization algorithms that are Kiefer-Wolfowitz (KW) type procedures with an added perturbing noise and partial step size restarting. The motivation stems from the use of KW-type procedures and Monte Carlo versions of simulated annealing algorithms in a wide range of applications. Using weak convergence approaches, our effort is directed to proving the convergence of the underlying algorithms under general noise processes.

Anacardic acid sensitizes prostate cancer cells to radiation therapy by regulating H2AX expression

Anacardic acid (6-pentadecylsalicylic acid, AA), a natural compound isolated from the traditional medicine Amphipterygiumadstringens, has been reported as potential antitumor agents in various cancers including prostate cancer (PC). However, the effects and mechanism of AA on the radiosensitivity of prostate cancer remains unknown. The results indicated that AA exhibited strong antitumor activity in PC cell lines, either as a single agentor in combination with radiation. AA significantly induced the downregulation of H2AX and p-H2AX expression, increase of cell apoptosis and decreasing of cell invasion, which were reversed by overexpressed H2AX. These results suggest that AA sensitize prostate cancer cells to radiation therapy by repressing H2AX expression.

Kelvin probe imaging of photo-injected electrons in metal oxide nanosheets from metal sulfide quantum dots under remote photochromic coloration

Metal oxide and quantum dot (QD) heterostructures have attracted considerable recent attention as materials for developing efficient solar cells, photocatalysts, and display devices, thus nanoscale imaging of trapped electrons in these heterostructures provides important insight for developing efficient devices. In the present study, Kelvin probe force microscopy (KPFM) of CdS quantum dot (QD)-grafted Cs4W11O36(2-) nanosheets was performed before and after visible-light irradiation. After visible-light excitation of the CdS QDs, the Cs4W11O36(2-) nanosheet surface exhibited a decreased work function in the vicinity of the junction with CdS QDs, even though the Cs4W11O36(2-) nanosheet did not absorb visible light. X-ray photoelectron spectroscopy revealed that W(5+) species were formed in the nanosheet after visible-light irradiation. These results demonstrated that excited electrons in the CdS QDs were injected and trapped in the Cs4W11O36(2-) nanosheet to form color centers. Further, the CdS QDs and Cs4W11O36(2-) nanosheet composite films exhibited efficient remote photochromic coloration, which was attributed to the quantum nanostructure of the film. Notably, the responsive wavelength of the material is tunable by adjusting the size of QDs, and the decoloration rate is highly efficient, as the required length for trapped electrons to diffuse into the nanosheet surface is very short owing to its nanoscale thickness. The unique properties of this photochromic device make it suitable for display or memory applications. In addition, the methodology described in the present study for nanoscale imaging is expected to aid in the understanding of electron transport and trapping processes in metal oxide and metal chalcogenide heterostructure, which are crucial phenomena in QD-based solar cells and/or photocatalytic water-splitting systems.

Expression of G protein αq Subunit is Decreased in Lymphocytes from Patients with Rheumatoid Arthritis and is Correlated with Disease Activity

Gαq, the alpha subunit of Gq, a member of the Gq/11 sub-family, was reported to inhibit phosphatidylinositol-3-Kinase (PI3K) activation and prevent the activation of Akt. Previous studies demonstrated that mice losing Gαq in their immune system could spontaneously develop inflammatory arthritis. In this study, we showed that the Gαq expressions at mRNA and protein levels in the peripheral blood lymphocytes (PBLs) from patients with rheumatoid arthritis (RA) were significantly decreased in comparison of which in healthy individuals. The expression levels of Gαq mRNA in PBLs from patients with RA were correlated with RA disease activity (DAS28), anti-cyclic citrullinated protein antibodies, C-reactive protein and rheumatoid factor. We also demonstrated that Gαq controlled the apoptosis of RA PBLs through regulating the activity of Mcl-1 and caspase-3. These data suggested that Gαq might be involved in the pathogenesis of RA by regulating PBLs apoptosis.

Renal calculus complicated with squamous cell carcinoma of renal pelvis: Report of two cases

Longstanding renal calculus is a risk factor of squamous cell carcinoma (SCC) of the renal pelvis. It is highly aggressive and usually diagnosed at advanced stages with a poor prognosis. We present two cases of kidney stone complications with renal pelvic SCC. These two patients had a radical nephrectomy and the dissected tissues were renal pelvic SCC. Our cases further emphasize that renal pelvic SCC should be considered in patients with longstanding renal calculus. These cases contribute greatly to an early diagnosis and early treatment, both of which will significantly minimize the damage of, and markedly improve the prognosis of, renal pelvic SCC.

Renal access through the inferior calyx is associated with higher risk of severe bleeding after percutaneous nephrolithotomy

INTRODUCTION

Hemorrhage is a major complication after percutaneous nephrolithotomy (PCNL). In the current study, we analyzed the risk factors for severe bleeding after PCNL.

MATERIAL AND METHODS

Medical records of 982 consecutive patients undergoing PCNL at the Department of Urology, the Third Xiangya Hospital, were reviewed. The type of stone included: solitary (n = 471), multiple (n = 192) and staghorn (n = 319). 139 patients had renal stones of solitary kidney or functional solitary kidney. The puncture site was the inferior calyx in 246 cases, the middle calyx in 651 cases, and the upper calyx in the remaining 85 cases.

RESULTS

The success rate (complete removal of the stone) was 92.8%, 73.4%, and 80.9% for solitary, multiple and staghorn stones, respectively. Severe bleeding occurred in 3.25% (8/246) of the cases with inferior calyx access, and 0.3% (2/651) in cases with middle calyx access. No severe bleeding occurred in patients with upper calyx access. The bleeding was controlled successfully with focal embolization under angiography in all 10 cases.

CONCLUSIONS

Severe postoperative bleeding after PCNL is associated with renal puncture via the inferior calyx, multiple renal stones and solitary kidney stones.

Adenoviral vector-mediated overexpression of osteoprotegerin accelerates osteointegration of titanium implants in ovariectomized rats

This study investigated the efficacy of human osteoprotegerin (hOPG) transgene to accelerate osteointegration of titanium implant in ovariectomized (OVX) rats. Bone marrow stromal cells transduced with Ad-hOPG-EGFP could sustainedly express hOPG. Osteoclast precursor RAW264.7 cells treated by the hOPG were examined by tartrate-resistant acid phosphatase (TRAP) staining and bone slice resorption assay. The results showed differentiation and function of osteoclasts were significantly suppressed by hOPG in vitro. Ad-hOPG-EGFP was locally administered to the bone defect prior to implant placement in OVX and sham rats. After 3, 7, 28 days of implantation, the femurs were harvested for molecular and histological analyses. Successful transgene expression was confirmed by western blot and cryosectioning. A significant reduction in TRAP+ numbers was detected in Ad-hOPG-EGFP group. Real-time reverse transcriptase-PCR examination revealed that hOPG transgene markedly diminished the expression of cathepsin K and receptor activator for nuclear factor-κ B ligand in vivo. The transgene hOPG modification revealed a marked increasing osteointegration and restored implant stability in OVX rats (P<0.01), compared with the control groups (Ad-EGFP or sterilized phosphate-buffered saline) 28 days after implantation. In conclusion, hOPG via direct adenovirus-mediated gene transfer could accelerate osteointegration of titanium implants in OVX rats. Osteoprotegerin gene therapy may be an effective strategy to osteointegration of implants under osteoporotic conditions.