SO2 Initiates the Efficient Conversion of NO2 to HONO on MgO Surface

Nitrous acid (HONO) is an important source of hydroxyl radical (OH) that determines the fate of many chemically active and climate relevant trace gases. However, the sources and the formation mechanisms of HONO remain poorly understood. In this study, the effect of SO₂ on the heterogeneous reactions of NO₂ on MgO as a mineral dust surrogate was investigated. The reactivity of MgO to NO₂ is weak, while coexisting SO₂ can increase the uptake coefficients of NO₂ on MgO by 2-3 orders of magnitude. The uptake coefficients of NO₂ on SO₂-aged MgO are independent of NO₂ concentrations in the range of 20-160 ppbv and relative humidity (0-70%RH). The reaction mechanism was demonstrated to be a redox reaction between NO₂ and surface sulfite. In the presence of SO₂, NO₂ was reduced to nitrite under dry conditions, which could be further converted to gas-phase HONO in humid conditions. These results suggest that the reductive effect of SO₂ on the heterogeneous conversion of NO₂ to HONO may have a significant contribution to the unknown sources of HONO observed in polluted areas (for example, in China).

Antidiabetic drug metformin mitigates ovarian cancer SKOV3 cell growth by triggering G2/M cell cycle arrest and inhibition of m-TOR/PI3K/Akt signaling pathway

OBJECTIVE

Metformin is one of most extensively prescribed oral hypoglycemic drug and has received increased attention in recent times for its antitumorigenic potential. Many possible mechanisms have been proposed for the ability of metformin to overturn cancer growth in vitro and in vivo. The objective of the present study was to evaluate the anticancer activity of metformin against ovarian SKOV3 cancer cells.

MATERIALS AND METHODS

Anticancer activity and IC50 value of metformin were determined by MTT assay. Reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and effect on cycle were determined by flow cytometry. Protein expression was estimated by Western blotting.

RESULTS

Results indicated that metformin exhibited an IC50 of 20 mM against ovarian SKOV3 cancer cell line. Metformin also caused DNA damage in SKOV3 cells and also prompted ROS-mediated alterations in mitochondrial membrane potential. Nonetheless, it triggered cell cycle arrest of SKOV3 at G2/M checkpoint. The activation of the PI3K/AKT/mTOR pathway plays a vital role in ovarian cancer tumorigenesis, progression and chemotherapy resistance. The results showed that metformin significantly inhibited the expression levels of key proteins of PI3K/Akt/mTOR signaling pathway.

CONCLUSIONS

We propose that metformin exhibits anticancer activity in SKOV3 cells and may prove beneficial in the management of ovarian cancers.

Cytosolic proteome profiling of monocytes for male osteoporosis

In male Caucasians with discordant hip bone mineral density (BMD), we applied the subcellular separation and proteome profiling to investigate the monocytic cytosol. Three BMD-associated proteins (ALDOA, MYH14, and Rap1B) were identified based on multiple omics evidence, and they may influence the pathogenic mechanisms of osteoporosis by regulating the activities of monocytes.

INTRODUCTION

Osteoporosis is a serious public health problem, leading to significant mortality not only in aging females but also in males. Peripheral blood monocytes (PBMs) play important roles in bone metabolism by acting as precursors of osteoclasts and producing cytokines important for osteoclast development. The first cytosolic sub-proteome profiling analysis was performed in male PBMs to identify differentially expressed proteins (DEPs) that are associated with BMDs and risk of osteoporosis.

METHODS

Here, we conducted a comparative proteomics analysis in PBMs from Caucasian male subjects with discordant hip BMD (29 low BMD vs. 30 high BMD). To decrease the proteome complexity and expand the coverage range of the cellular proteome, we separated the PBM proteome into several subcellular compartments and focused on the cytosolic fractions, which are involved in a wide range of fundamental biochemical processes.

RESULTS

Of the total of 3796 detected cytosolic proteins, we identified 16 significant (P < 0.05) and an additional 22 suggestive (P < 0.1) DEPs between samples with low vs. high hip BMDs. Some of the genes for DEPs, including ALDOA, MYH14, and Rap1B, showed an association with BMD in multiple omics studies (proteomic, transcriptomic, and genomic). Further bioinformatics analysis revealed the enrichment of DEPs in functional terms for monocyte proliferation, differentiation, and migration.

CONCLUSIONS

The combination strategy of subcellular separation and proteome profiling allows an in-depth and refined investigation into the composition and functions of cytosolic proteome, which may shed light on the monocyte-mediated pathogenic mechanisms of osteoporosis.

Regulatory effects of bone morphogenetic protein-4 on tumour necrosis factor-α-suppressed Runx2 and osteoprotegerin expression in cementoblasts

OBJECTIVES

Root resorption is a common phenomenon presented in periodontitis and orthodontic treatment, both of which are accompanied by an elevated TNF-α expression level in the periodontal tissues. Previously, we proved that TNF-α showed an inhibitory effect on cementoblast differentiation, mineralization and proliferation. However, the effect of TNF-α on Runx2 and osteoprotegerin (OPG) expression remains undetermined. This study aimed to identify the influence of TNF-α on Runx2 and OPG expression in cementoblasts and to test whether BMP-2,-4,-6,-7 would affect TNF-α-regulated Runx2 and OPG.

MATERIALS AND METHODS

An immortalized murine cementoblast cell line OCCM-30 was used in this study. The expression of Runx2 and OPG were examined by qRT-PCR after stimulating cells with TNF-α. The role of signalling pathways, including MAPK, PI3K-Akt and NF-κB, were studied with the use of specific inhibitors. Cells were treated with TNF-α in combination with BMP-2,-4,-6 or -7, then the expression of Runx2 and OPG, the activity of MAPK and NF-κB pathways, and the proliferation ability were evaluated by qRT-PCR, Western blot and MTS assay respectively.

RESULTS

TNF-α inhibited Runx2 and OPG mRNAs in OCCM-30 cells, and the inhibitory effects were further aggravated by blocking p38 MAPK or NF-κB pathway. TNF-α-inhibited Runx2 and OPG were up-regulated by BMP-4. The p38 MAPK and Erk1/2 pathways were further activated by the combined treatment of BMP-4 and TNF-α compared with TNF-α alone. Finally, the TNF-α-suppressed proliferation was not obviously affected by BMP-2,-4,-6 or -7.

CONCLUSIONS

TNF-α inhibited Runx2 and OPG in cementoblasts, and the p38 MAPK and NF-κB pathways acted in a negative-feedback way to attenuate the inhibitory effects. TNF-α-inhibited Runx2 and OPG could be effectively up-regulated by BMP-4; however, further investigations are needed to fully elaborate the underlying mechanisms.

Primary central nervous system diffuse large B-cell lymphoma shows an activated B-cell-like phenotype with co-expression of C-MYC, BCL-2, and BCL-6

Diffuse large B-cell lymphoma (DLBCL) is the most common non-Hodgkin lymphoma, whose main prognostic factor is closely related to germinal center B-cell-like subtype (GCB- DLBCL) or activated B-cell-like type (non-GCB-DLBCL). The most common type of primary central nervous system lymphoma is diffuse large B-cell type with poor prognosis and the reason is unclear. This study aims to stratify primary central nervous system diffuse large B-cell lymphoma (PCNS-DLBCL) according to the cell-of-origin (COO) and to investigate the multiple proteins expression of C-MYC, BCL-6, BCL-2, TP53, further to elucidate the reason why primary central nervous system diffuse large B-cell lymphoma possesses a poor clinical outcome as well. Nineteen cases of primary central nervous system DLBCL were stratified according to immunostaining algorithms of Hans, Choi and Meyer (Tally) and we investigated the multiple proteins expression of C-MYC, BCL-6, BCL-2, TP53. The Epstein-Barr virus and Borna disease virus infection were also detected. Among nineteen cases, most (15-17 cases) were assigned to the activated B-cell-like subtype, highly expression of C-MYC (15 cases, 78.9%), BCL-2 (10 cases, 52.6%), BCL-6 (15 cases, 78.9%). Unfortunately, two cases were positive for PD-L1 while PD-L2 was not expressed in any case. Two cases infected with BDV but no one infected with EBV. In conclusion, most primary central nervous system DLBCLs show an activated B-cell-like subtype characteristic and have multiple expressions of C-MYC, BCL-2, BCL-6 protein, these features might be significant factor to predict the outcome and guide treatment of PCNS-DLBCLs.

Adenovirus vector-mediated ex vivo gene transfer of brain-derived neurotrophic factor (BDNF) tohuman umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) promotescrush-injured rat sciatic nerve regeneration

This study was designed toinvestigate the efficacy of adenovirus vector-mediated brain-derived neurotrophic factor (BDNF) ex vivo gene transfer to human umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) in a rat sciatic nerve crush injury model. BDNF protein and mRNA expression after infection was checked through an enzyme-linked immunosorbent assay (ELISA) and quantitative real-time polymerase chain reaction (qRT-PCR). Male Sprague-Dawley rats (200-250g, 6 weeks old) were distributed into threegroups (n=20 each): the control group, UCB-MSC group, and BDNF-adenovirus infected UCB-MSC (BDNF-Ad+UCB-MSC) group. UCB-MSCs (1×10⁶cells/10μl/rat) or BDNF-Ad+UCB-MSCs (1×10⁶cells/10μl/rat)were transplantedinto the rats at the crush site immediately after sciatic nerve injury. Cell tracking was done with PKH26-labeled UCB-MSCs and BDNF-Ad+UCB-MSCs (1×10⁶cells/10μl/rat). The rats were monitored for 4 weeks post-surgery. Results showed that expression of BDNF at both the protein and mRNA levels was higher inthe BDNF-Ad+UCB-MSC group compared to theUCB-MSC group in vitro.Moreover, BDNF mRNA expression was higher in both UCB-MSC group and BDNF-Ad+ UCB-MSC group compared tothe control group, and BDNF mRNA expression in theBDNF-Ad+UCB-MSC group was higher than inboth other groups 5days after surgeryin vivo. Labeled neurons in the dorsal root ganglia (DRG), axon counts, axon density, and sciatic function index were significantly increased in the UCB-MSC and BDNF-Ad+ UCB-MSCgroupscompared to the controlgroup four weeksaftercell transplantation. Importantly,the BDNF-Ad+UCB-MSCgroup exhibited more peripheral nerve regeneration than the other two groups.Our results indicate thatboth UCB-MSCs and BDNF-Ad+UCB-MSCscan improve rat sciatic nerve regeneration, with BDNF-Ad+UCB-MSCsshowing a greater effectthan UCB-MSCs.

Inhibition of group 1 p21-activated kinases suppresses pancreatic stellate cell activation and increases survival of mice with pancreatic cancer

Pancreatic cancer remains one of the most lethal of all solid tumors. Pancreatic stellate cells (PSCs) are primarily responsible for the fibrosis that constitutes the stroma and p21-activated kinase 1 (PAK1) may have a role in signalling pathways involving PSCs. This study aimed to examine the role of PAK1 in PSCs and in the interaction of PSCs with pancreatic cancer cells. Human PSCs were isolated using the modified outgrowth method. The effect of inhibiting PAK1 with group 1 PAK inhibitor, FRAX597, on cell proliferation and apoptosis in vitro was measured by thymidine incorporation and annexin V assays, respectively. The effect of depleting host PAK1 on the survival of mice with pancreatic Pan02 cell tumors was evaluated using PAK1 knockout (KO) mice. PAK1 was expressed in isolated PSCs. FRAX597 reduced the activation of PSCs, inhibited PSC proliferation, and increased PSC apoptosis at least in partial by inhibiting PAK1 activity. The decreased expression and activity of PAK1 in PAK1 KO mice tumors was associated with an increased mouse survival. These results implicate PAK1 as a regulator of PSC activation, proliferation and apoptosis. Targeting stromal PAK1 could increase therapeutic response and survival of patients with pancreatic cancer.

[Effects of recombinant human growth hormone on local expression of insulin-like growth factor-Ⅰ during orthodontic tooth movement]

OBJECTIVE

To explore in vivo the expression of insulin-like growth factor-Ⅰ(IGF-Ⅰ)under stress, and to analyze changes of the local expression related to recombinant human growth hormone(rhGH)treatment.

METHODS

Forty Wistar rats were randomly divided into control and growth hormone groups, 20 in each group. A force of 0.49 N was applied to move the right upper first molars mesially. The growth hormone group and control group received daily subcutaneous injections of rhGH and equivalent volumes of saline, respectively. The rats were sacrificed on days 1, 3, 7 and 14. Micro-CT-reconstructed images were used to survey root resorption, and horizontal sections of the maxillae were prepared for tartrate-resistant acid phosphate(TRAP)and immunohistochemistry staining.

RESULTS

Tooth moved faster in the growth hormone group([0.291±0.017], [0.513±0.111]mm)than in the control group([0.245±0.033], [0.368± 0.052]mm)on days 7 and 14(P<0.05). More osteoclasts on day 3, and fewer osteoclasts on day 7 were observed in the growth hormone group([4.0±0.7], [2.6±0.6]cell/high-power field)than in the control group([2.8±0.6], [3.8±0.8]cell/high-power field)(P<0.05). The number of IGF-Ⅰ positive osteoclasts in the growth hormone group([4.7 ± 0.7]cell/high-power field)was significantly greater than that in the control group([2.7±0.5]cell/high-power field)(P<0.01)on day 3. Compared with the control group([18.6±1.5], [23.3± 3.8]cell/high-power field), IGF-Ⅰ positive PDL cells increased on days 7 and 14 in the growth hormone groups([29.6±3.4], [37.5±6.1]cell/high-power field)(P<0.01).

CONCLUSIONS

rhGH could stimulate IGF-Ⅰ expression in PDL, and accelerate bone remodeling and tooth movement.

Reporting quality of randomized controlled trial abstracts: survey of leading general dental journals

BACKGROUND

The authors conducted a study to assess the reporting quality of randomized controlled trial (RCT) abstracts published in leading general dental journals, investigate any improvement after the release of the Consolidated Standards of Reporting Trials (CONSORT) for Abstracts guidelines, and identify factors associated with better reporting quality.

METHODS

The authors searched PubMed for RCTs published in 10 leading general dental journals during the periods from 2005 to 2007 (pre-CONSORT period) and 2010 to 2012 (post-CONSORT period). The authors evaluated and scored the reporting quality of included abstracts by using the original 16-item CONSORT for Abstracts checklist. The authors used risk ratios and the t test to compare the adequate reporting rate of each item and the overall quality in the 2 periods. The authors used univariate and multivariate regressions to identify predictors of better reporting quality.

RESULTS

The authors included and evaluated 276 RCT abstracts. Investigators reported significantly more checklist items during the post-CONSORT period (mean [standard deviation {SD}], 4.53 [1.69]) than during the pre-CONSORT period (mean [SD], 3.87 [1.10]; mean difference, -0.66 [95% confidence interval, -0.99 to -0.33]; P < .001). Investigators reported 3 items-interventions, objective, and conclusions-adequately in most of the abstracts (> 80%). In contrast, the authors saw sufficient reporting of randomization, recruitment, outcome in the results section, and funding in none of the pre-CONSORT abstracts and less than 2% of the post-CONSORT abstracts. On the basis of the multivariate analysis, a higher impact factor (P < .001) and a publication date in the post-CONSORT period (P = .003) were associated significantly with higher reporting quality.

CONCLUSIONS

The reporting quality of RCT abstracts from leading general dental journals has improved significantly, but there is still room for improvement.

PRACTICAL IMPLICATIONS

Joint efforts by authors, reviewers, journal editors, and other stakeholders to improve the reporting of dental RCT abstracts are needed.

Influence of metal-mediated aerosol-phase oxidation on secondary organic aerosol formation from the ozonolysis and OH-oxidation of α-pinene

The organic component is the most abundant fraction of atmospheric submicron particles, while the formation mechanisms of secondary organic aerosol (SOA) are not fully understood. The effects of sulfate seed aerosols on SOA formation were investigated with a series of experiments carried out using a 9 m³ smog chamber. The presence of FeSO₄ or Fe₂(SO₄)₃ seed aerosols decreased SOA yields and increased oxidation levels in both ozonolysis and OH-oxidation of α-pinene compared to that in the presence of ZnSO₄ or (NH₄)₂SO₄. These findings were explained by metal-mediated aerosol-phase oxidation of organics: reactive radicals were generated on FeSO₄ or Fe₂(SO₄)₃ seed aerosols and reacted further with the organic mass. This effect would help to explain the high O/C ratios of organics in ambient particles that thus far cannot be reproduced in laboratory and model studies. In addition, the gap in the SOA yields between experiments with different seed aerosols was more significant in OH-oxidation experiments compared to ozonolysis experiments, while the gap in estimated O/C ratios was less obvious. This may have resulted from the different chemical compositions and oxidation levels of the SOA generated in the two systems, which affect the branching ratio of functionalization and fragmentation during aerosol oxidation.

Ligand-assisted mechanochemical synthesis of ceria-based catalysts for the selective catalytic reduction of NO by NH3

A ligand-assisted ball milling method was used to prepare the CeO₂/TiO₂ catalyst for the NH₃-SCR reaction.

Diagnosis and Treatment of Pythium Insidiosum Corneal Ulcer in a Chinese Child: A Case Report and Literature Review

Patient: Male, 7

Final Diagnosis: Pythium insidiosum

Symptoms: Painful vision loss • red eye

Medication:—

Clinical Procedure: Application of multiple antifungal medicines followed by the penetrating keratoplasty

Specialty: Ophthalmology

Newly developed and validated eosinophilic esophagitis histology scoring system and evidence that it outperforms peak eosinophil count for disease diagnosis and monitoring

Eosinophilic esophagitis (EoE) is diagnosed by symptoms, and at least 15 intraepithelial eosinophils per high power field in an esophageal biopsy. Other pathologic features have not been emphasized. We developed a histology scoring system for esophageal biopsies that evaluates eight features: eosinophil density, basal zone hyperplasia, eosinophil abscesses, eosinophil surface layering, dilated intercellular spaces (DIS), surface epithelial alteration, dyskeratotic epithelial cells, and lamina propria fibrosis. Severity (grade) and extent (stage) of abnormalities were scored using a 4-point scale (0 normal; 3 maximum change). Reliability was demonstrated by strong to moderate agreement among three pathologists who scored biopsies independently (P ≤ 0.008). Several features were often abnormal in 201 biopsies (101 distal, 100 proximal) from 104 subjects (34 untreated, 167 treated). Median grade and stage scores were significantly higher in untreated compared with treated subjects (P ≤ 0.0062). Grade scores for features independent of eosinophil counts were significantly higher in biopsies from untreated compared with treated subjects (basal zone hyperplasia P ≤ 0.024 and DIS P ≤ 0.005), and were strongly correlated (R-square >0.67). Principal components analysis identified three principal components that explained 78.2% of the variation in the features. In logistic regression models, two principal components more closely associated with treatment status than log distal peak eosinophil count (PEC) (R-square 17, area under the curve (AUC) 77.8 vs. R-square 9, AUC 69.8). In summary, the EoE histology scoring system provides a method to objectively assess histologic changes in the esophagus beyond eosinophil number. Importantly, it discriminates treated from untreated patients, uses features commonly found in such biopsies, and is utilizable by pathologists after minimal training. These data provide rationales and a method to evaluate esophageal biopsies for features in addition to PEC.

Effects of piezosurgery in accelerating the movement of orthodontic alveolar bone tooth of rats and the expression mechanism of BMP-2

The aim of the study was to investigate the effects of piezosurgery in accelerating the movement of orthodontic alveolar bone tooth of rats and the expression mechanism of bone morphogenetic protein-2 (BMP-2). Adult male Wistar rats (n=30), with an age range of 14–15 weeks, and an average weight of 250±16 g were used. The animals were randomly divided into the control and observation groups. The rats in the control group were injected with 25-dihydroxyvitamin (1,25-dihydroxycholecalciferol) into their dental ligament. The rats in the observation group were placed with an orthodontic device between the first molar and central incisor in the maxillary. On the first day after animal treatment, piezosurgery stimulation was performed on the first molar in maxillary. The changes of the movement distance of the first molar and gum surface temperature on days 1, 3, 5, 7 and 14 were then compared. Immunohistochemical staining was performed to detect the expression of BMP-2 of periodontal tissue in the tension side of the first molar. Tooth movement distance in the observation group on days 5, 7 and 14 was significantly longer than that in the control group (p<0.05). The gum surface temperature of the observation group was elevated to some extent, peaking after 20 min. BMP-2 mRNA and protein levels in the observation group were significantly higher than those of the control group at days 3, 5, 7 and 14 (p<0.05). In conclusion, piezosurgery may significantly accelerate the movement of orthodontic alveolar bone tooth of rats and be associated with an increasing BMP-2 expression.

Esthetic Restoration of Multiple Congenitally Missing Anterior Teeth with Oral Implants: A Clinical Case Report

Having multiple congenitally missing anterior teeth heavily influences the patient's countenance and pronunciation. There are few reports on the esthetic restoration of such situations with oral implants. This clinical case history report presents a multidisciplinary approach to treat a young woman with multiple congenitally missing anterior teeth using implant-supported prostheses. The treatment steps and clinical implications are discussed.

Ozonolysis of Trimethylamine Exchanged with Typical Ammonium Salts in the Particle Phase

Alkylamines contribute to both new particle formation and brown carbon. The toxicity of particle-phase amines is of great concern in the atmospheric chemistry community. Degradation of particulate amines may lead to secondary products in the particle phase, which are associated with changes in the adverse health impacts of aerosols. In this study, O₃ oxidation of particulate trimethylamine (TMA) formed via heterogeneous uptake of TMA by (NH₄)₂SO₄, NH₄HSO₄, NH₄NO₃ and NH₄Cl, was investigated with in situ attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and proton transfer reaction mass spectrometry (PTR-MS). HCOOH, HCHO, CH₃N═CH₂, (CH₃)₂NCHO, CH₃NO₂, CH₃N(OH)CHO, CH₃NHOH and H₂O were identified as products on all the substrates based upon IR (one-dimensional IR and two-dimensional correlation infrared spectroscopy), quantum chemical calculation and PTR-MS results. A reaction mechanism was proposed to explain the observed products. This work demonstrates that oxidation might be a degradation pathway of particulate amines in the atmosphere. This will aid in understanding the fate of particulate amines formed by nucleation and heterogeneous uptake and their potential health impacts during atmospheric aging.