Publication date: November 2016
Source:Atmospheric Environment, Volume 145
Author(s): Thomas A. Cahill, David E. Barnes, Jonathan A. Lawton, Roger Miller, Nicholas Spada, Robert D. Willis, Sue Kimbrough
As one component of a study investigating the impact of vehicle emissions on near-road air quality, human exposures, and potential health effects, particles were measured from September 21 to October 30, 2010 on both sides of a major roadway (Interstate-96) in Detroit. Traffic moved freely on this 12 lane freeway with a mean velocity of 69 mi/hr. with little braking and acceleration. The UC Davis DELTA Group rotating drum (DRUM) impactors were used to collect particles in 8 size ranges at sites nominally 100 m south, 10 m north, 100 m north, and 300 m north of the highway. Ultra-fine particles were continuously collected at the 10 m north and 100 m north sites. Samples were analyzed every 3 h for mass (soft beta ray transmission), 42 elements (synchrotron-induced x-ray fluorescence) and optical attenuation (350–800 nm spectroscopy). A three day period of steady southerly winds along the array allowed direct measurement of freeway emission rates for coarse (10 > Dp > 1.0 μm), PM2.5, very fine (0.26 > Dp > 0.09 μm), and ultra-fine (Dp < 0.09 μm) particles. The PM2.5 mass concentrations were modeled using literature emission rates during the south to north wind periods, and averaged 1.6 ± 0.5 μg/m3, versus the measured value of 2.0 ± 0.7 μg/m3. Using European freeway emission rates from 2010, and modeling them at the I-96 site, we would predict roughly 3.1 μg/m3 of PM2.5 particles, corrected from the 4.9 PM10 value by their measured road dust contributions. Using California car and truck emission rates of 1973, this value would have been about 16 μg/m3, corrected down from the 19 μg/m3 PM5.0 using measured roadway dust contributions. This would have included 2.7 μg/m3 of lead, versus the 0.0033 μg/m3 measured. Very fine particles were distributed across the array with a relatively weak falloff versus distance. For the ultra-fine particles, emissions of soot and metals seen in vehicular braking studies correlated with traffic at the 10 m site, but only the soot was statistically significant at the 100 m north site. Otherwise, the 10 m north and 100 m north sites were essentially identical in mean concentration and highly correlated in time for most of the 5 week study. This result supports earlier publications showing the ability of very fine and ultra-fine particles to transport to sites well removed from the freeway sources. The concentrations of very fine and ultra-fine metals from brake wear and zinc in motor oil observed in Detroit have the potential of being a significant component in statistically established PM2.5 mortality rates.
http://ift.tt/2csnloe
Σάββατο 24 Σεπτεμβρίου 2016
Transition metals in coarse, fine, very fine and ultra-fine particles from an interstate highway transect near Detroit
Urban – Wetland contrast in turbulent exchange of methane
Publication date: November 2016
Source:Atmospheric Environment, Volume 145
Author(s): Włodzimierz Pawlak, Krzysztof Fortuniak, Mariusz Siedlecki, Mariusz Zieliński
Continuous eddy-covariance measurements of turbulent methane exchange between the ground and the atmosphere were carried out during the period from July 2013 to September 2015. The measurement sites were located in areas characterized by different types of use: the city (Łódź, central Poland) and the wetlands of Biebrza National Park (northeastern Poland). Regardless of the type of surface, such long-term, continuous measurements of the turbulent fluxes of methane are rare. Our aim was to investigate the temporal variability of the turbulent methane exchange in the surface–atmosphere system, while considering the impact of land use. Because cities are a huge source of atmospheric carbon dioxide, we compared the intensity of methane emissions from the city as compared to the wetland, which is considered to be the most intense natural source atmospheric methane. In both cases, the results show a clear prevalence of positive as compared with negative fluxes. This shows that both areas are net sources of methane to the troposphere. The measurements also demonstrated the existence of a clear annual cycle of turbulent methane flux in the centre of the city (average values in winter ranged from ∼40 to 60 nmol m−2·s−1 and were significantly greater than values measured in summer) as well as in the wetlands, where maximum values were observed during the warm part of the year (approximately 80 nmol m−2·s−1 or more). The different times of maximum CH4 flux (FCH4) occurrence resulted from the differentiation of processes that determine methane emissions: in the city these are anthropogenic emissions (strongest in winter); in the wetland, natural processes dominate. The diurnal variability of FCH4 was faintly detectable, except for the cold half of the year in the city and the warm half of the year in the wetland. The studied area of the centre of Łódź, in turn, is also characterized by a weekly cycle of methane exchange: the values measured on working days were higher by 6.6% (winter) to 5.6% (summer) than those observed on weekends. Differences in the annual exchange of methane in 2014 were insignificant: the centre of Łódź emitted 17.4 g m−2 net, while the wetland emitted about 18.7 g m−2 net. The results of the measurements performed during the period from January to September 2015, however, suggest that a very dry summer, drying of the soil and, consequently, a reduced water level in the fen significantly reduced the ability of the wetland to emit methane. This pattern was not observed in the city.
Graphical abstract
http://ift.tt/2di0FNx
The Parietal Memory Network Activates Similarly for True and Associative False Recognition Elicited via the DRM Procedure
Source:Cortex
Author(s): Kathleen B. McDermott, Adrian W. Gilmore, Steven M. Nelson, Jason M. Watson, Jeffrey G. Ojemann
Neuroimaging investigations of human memory encoding and retrieval have revealed that multiple regions of parietal cortex contribute to memory. Recently, a sparse network of regions within parietal cortex has been identified using resting state functional connectivity MRI techniques). The regions within this network exhibit consistent task-related responses during memory formation and retrieval, leading to its being called the parietal memory network (PMN). Among its signature patterns are: deactivation during initial experience with an item (e.g., encoding); activation during subsequent repetitions (e.g., at retrieval); greater activation for successfully retrieved familiar words than novel words (e.g., hits relative to correctly-rejected lures). The question of interest here is whether novel words that are subjectively experienced as having been recently studied would elicit PMN activation similar to that of hits. That is, we compared old items correctly recognized to two types of novel items on a recognition test: those correctly identified as new and those incorrectly labeled as old due to their strong associative relation to the studied words (in the DRM false memory protocol). Subjective oldness plays a strong role in driving activation, as hits and false alarms activated similarly (and greater than correctly-rejected lures).
http://ift.tt/2dry4En
Chemical characteristics of aerosol and rain water during an El Niño and PDO influenced Indian summer monsoon
Publication date: November 2016
Source:Atmospheric Environment, Volume 145
Author(s): Pradhi Rajeev, Prashant Rajput, Tarun Gupta
According to the meteorological long-term variability pattern, year 2015 was influenced by El Niño and PDO (Pacific Decadal Oscillation; causes weakening of Indian Summer Monsoon). These conditions facilitate the assessment of chemical characteristics of fine-mode ambient aerosols (PM2.5; n = 48) and individual rain waters (pH: 6.4–7.6; n = 15) during the South-west monsoon (July–September 2015) in the central Indo-Gangetic Plain (IGP; Kanpur). Water-soluble ionic species (WSIS) have been measured to assess the undergoing processes (neutralization, formation and below-cloud scavenging) and estimate their dry and wet deposition fluxes. The ∑WSIS varies from 4 to 32 μg/m3 in PM2.5, whereas it ranges from 32 to 102 mg/L in rain waters. The NH4+ and SO42− are found to be predominant in PM2.5 (16–120 μg/m3), whereas HCO3− and Ca2+ are predominant in rain water samples. The difference in chemical composition of PM2.5 and rain water is largely attributed to additional contribution of coarse-mode mineral dust in rain water. The Ca2+ and Mg2+ in both aerosols and rain water samples are associated with HCO3−. The NO3− and SO42− are neutralized predominantly by NH4+ and ∑−/∑+ ratio is ≈ 1 in both aerosols and rain waters. Furthermore, co-variability of NO3− with nss-Ca2+ in PM2.5 indicates role of fine-mode mineral dust surface in the formation of ammonium nitrate. Characteristic mass ratios (HCO3−/Ca2+ and SO42−/NH4+) in rain water look quite similar to those in aerosols (PM2.5). This suggests that below-cloud scavenging is predominant mechanism of aerosols wash-out. Dry deposition fluxes of Mg2+, NH4+ and SO42− are ∼13% of their wet deposition fluxes, whereas for K+, Ca2+ and NO3− it is <6%.
Graphical abstract
http://ift.tt/2di07r0
Application of the Approximate Bayesian Computation methods in the stochastic estimation of atmospheric contamination parameters for mobile sources
Source:Atmospheric Environment, Volume 145
Author(s): Piotr Kopka, Anna Wawrzynczak, Mieczyslaw Borysiewicz
In this paper the Bayesian methodology, known as Approximate Bayesian Computation (ABC), is applied to the problem of the atmospheric contamination source identification. The algorithm input data are on-line arriving concentrations of the released substance registered by the distributed sensors network. This paper presents the Sequential ABC algorithm in detail and tests its efficiency in estimation of probabilistic distributions of atmospheric release parameters of a mobile contamination source. The developed algorithms are tested using the data from Over-Land Atmospheric Diffusion (OLAD) field tracer experiment. The paper demonstrates estimation of seven parameters characterizing the contamination source, i.e.: contamination source starting position (x,y), the direction of the motion of the source (d), its velocity (v), release rate (q), start time of release (ts) and its duration (td). The online-arriving new concentrations dynamically update the probability distributions of search parameters. The atmospheric dispersion Second-order Closure Integrated PUFF (SCIPUFF) Model is used as the forward model to predict the concentrations at the sensors locations.
http://ift.tt/2d8nzp4
Fine-tuning the expression of microRNA-155 controls acetaminophen-induced liver inflammation
Publication date: November 2016
Source:International Immunopharmacology, Volume 40
Author(s): Kai Yuan, Xue Zhang, Lei Lv, Jiwei Zhang, Wei Liang, Peng Wang
Treatment of acetaminophen (APAP) in overdose can cause a potentially serious and fatal liver injury. MicroRNA-155 (miR-155), a multifunctional microRNA, is known to mediate inflammatory responses via regulating various target genes. In this study, we aimed to study the role of miR-155 in APAP-induced liver injury, using miR-155−/− mice and miR-155 in vivo intervention. We noted that miR-155 expression was significantly increased in liver and blood after APAP treatment. Knockout of miR-155 deteriorated APAP-induced liver damage, with the elevated serum levels of AST and ALT. The levels of various inflammatory mediators, such as TNF-α and IL-6, were markedly augmented in livers in the absence of miR-155. Moreover, miR-155 deficiency aberrantly activated NF-kappa-B signaling via enhancing p65 and IKKε expression. Finally, in vivo administration of miR-155 agomir attenuated APAP-induced liver damage, reduced the serum levels of AST and ALT, and dampened the NF-kB signaling. In conclusion, our data demonstrated that miR-155 protects the mice against APAP-induced liver damage via mediating NF-KB signaling pathway, suggesting that miR-155 might be a potential pharmaceutic target for treatment of APAP-induced liver inflammation.
http://ift.tt/2d7nsbI
Increased proportions of Tc17 cells and NK cells may be risk factors for disease progression in Hashimoto's thyroiditis
Publication date: November 2016
Source:International Immunopharmacology, Volume 40
Author(s): Yalei Liu, Ran You, Nan Yu, Yan Gong, Chenxue Qu, Yang Zhang, Guizhi Lu, Youyuan Huang, Hong Zhang, Ying Gao, Yanming Gao, Xiaohui Guo
Both cellular and humoral responses play important roles in the pathogenesis of Hashimoto's thyroiditis (HT). However, the immunological differences between euthyroid (mild HT) and hypothyroid (severe HT) patients are unknown. This study aimed to investigate the distribution of lymphocyte subsets and cytokine profiles in HT patients with differences in thyroid function.Peripheral blood was drawn from 18 healthy controls and 54 HT patients (33 patients with mild HT, 21 patients with severe HT). The percentages of B cell subsets, T cell subsets and NK cells were analyzed by flow cytometry. The levels of IL-21 and Bcl-6 mRNA were assessed using real-time PCR. The levels of serum IFN-γ, TNF-α, TGF-β, IL-4, IL-6, IL-10 and a proliferation-inducing ligand (APRIL) were measured by ELISA or cytometric bead array.The percentages of double-negative memory B cells, plasma cells, Tfh cells and Tc17 cells were higher in HT patients than in the healthy controls. The percentages of Tc17 cells and NK cells were higher in the patients with severe HT than in the patients with mild HT. The levels of serum APRIL, IL-6 and IL-10 were higher in the patients with severe HT than in those with mild HT. The percentage of NK cells was positively correlated with TSH levels in the HT patients.Our data indicate that the distribution of lymphocyte subsets and cytokine profiles is aberrant in HT patients, and the increased percentages of Tc17 cells and NK cells and increased cytokine levels might be involved in the progression of HT.
http://ift.tt/2cuwj9i
MRI of the posterolateral corner of the knee, please have a look
Publication date: Available online 23 September 2016
Source:Alexandria Journal of Medicine
Author(s): Mahmoud Agha
The knee PLC injuries are frequently seen, with other major knee injuries, such as ACL and PCL. Objective: This article aimed to clarify PLC injuries that could be diagnosed by MRI, and may have an impact on the management of the associated major knee injuries. Patient and methods: It was conducted through retrospective MRI revision of 1000 patients who were presented with post-traumatic knee complaints, from January 2011 to March 2016. Results: ITB band injuries were seen in 113 patients (11.3%), biceps tendon injury in 59 patients (5.9%), FCL injuries in 223 patients (22.3%), popliteus muscle injury in 53 patients (5.3%), PFL in 17 (1.7%), arcuate ligament injury in 38 patients (3.8%) and arcuate bone fracture (fibular styloid fracture) in 22 patients (2.2%). Overall PLC injuries recorded 283 patients, either as separate or combined PLC items. Of these 283 patients, 96 patients had associated ACL tear (33.9%), 19 had PCL tear (6.7%), 73 had medial corner injury (25.7%), 55 combined injuries (19.4%) and 40 isolated PLC injuries (14.1%). Conclusion: Different types of PLC injuries may occur in association with other major knee sectorial injuries that may require repair before the associated injured major sector correction, in an attempt to avoid early ACL or PCL graft failure.
http://ift.tt/2cANGUD
Scholar : Atlantic Studies, Volume 13, Issue 4, December 2016 is now available online on Taylor & Francis Online
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Scholar : Journal of the Institute of Conservation, Volume 39, Issue 2, September 2016 is now available online on Taylor & Francis Online
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Scholar : These new articles for Arts & Health are available online
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Scholar : These new articles for Aquatic Insects are available online
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Scholar : These new articles for Applied Developmental Science are available online
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Impact of Shaggy Aorta in Patients with Abdominal Aortic Aneurysm Following Open or Endovascular Aneurysm Repair
Publication date: Available online 24 September 2016
Source:European Journal of Vascular and Endovascular Surgery
Author(s): H. Kwon, Y. Han, M. Noh, J.G. Gwon, Y.-P. Cho, T.-W. Kwon
ObjectiveTo analyze the impact of the presence of shaggy aorta on 30 day morbidity and mortality and long-term survival in patients undergoing abdominal aortic aneurysm (AAA) repair.MethodsThis retrospective observational study included 447 consecutive patients who underwent AAA repair between January 2009 and December 2012. The study included 209 patients (47%) having open surgical repair (OSR) and 238 patients (53%) having endovascular aneurysm repair (EVAR).ResultsOf the 447 patients having elective AAA repair, 48 patients (11%) had shaggy aorta. Both the OSR (p = .005) and EVAR group (p = .007) demonstrated a higher 30 day morbidity and mortality in patients with shaggy aorta. On multivariate regression analysis, patients with shaggy aorta had 4.1 fold (95% CI = 1.7–9.7; p = .002) increase in 30 day morbidity and mortality. According to the Kaplan-Meier analysis, patients with shaggy aorta had significantly decreased long-term overall survival in comparison with the non-shaggy group (log-rank test; p = .005), and this resulted from comorbidities.ConclusionsShaggy aorta is a prominent risk factor associated with 30 day morbidity and mortality. Poor long-term survival was expected in patients with shaggy aorta.
http://ift.tt/2cPFKyz
Biocompatibility of implantable materials: An oxidative stress viewpoint
Source:Biomaterials, Volume 109
Author(s): Pierre-Alexis Mouthuy, Sarah J.B. Snelling, Stephanie G. Dakin, Lidija Milković, Ana Čipak Gašparović, Andrew J. Carr, Neven Žarković
Oxidative stress occurs when the production of oxidants surpasses the antioxidant capacity in living cells. Oxidative stress is implicated in a number of pathological conditions such as cardiovascular and neurodegenerative diseases but it also has crucial roles in the regulation of cellular activities. Over the last few decades, many studies have identified significant connections between oxidative stress, inflammation and healing. In particular, increasing evidence indicates that the production of oxidants and the cellular response to oxidative stress are intricately connected to the fate of implanted biomaterials. This review article provides an overview of the major mechanisms underlying the link between oxidative stress and the biocompatibility of biomaterials. ROS, RNS and lipid peroxidation products act as chemo-attractants, signalling molecules and agents of degradation during the inflammation and healing phases. As chemo-attractants and signalling molecules, they contribute to the recruitment and activation of inflammatory and healing cells, which in turn produce more oxidants. As agents of degradation, they contribute to the maturation of the extracellular matrix at the healing site and to the degradation of the implanted material. Oxidative stress is itself influenced by the material properties, such as by their composition, their surface properties and their degradation products. Because both cells and materials produce and react with oxidants, oxidative stress may be the most direct route mediating the communication between cells and materials. Improved understanding of the oxidative stress mechanisms following biomaterial implantation may therefore help the development of new biomaterials with enhanced biocompatibility.
http://ift.tt/2drqLwy
Scholar : These new articles for Archives of Agronomy and Soil Science are available online
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CD8+ T cell response to human papillomavirus 16 E7 is able to predict survival outcome in oropharyngeal cancer
Source:European Journal of Cancer, Volume 67
Author(s): Liam Masterson, Matt Lechner, Sarah Loewenbein, Hassan Mohammed, Cameron Davies-Husband, Tim Fenton, Holger Sudhoff, Piyush Jani, Peter Goon, Jane Sterling
IntroductionImmunological response to human papillomavirus (HPV) in the development and progression of HPV16+ oropharyngeal squamous cell carcinoma (OPSCC) (accounting for the majority of viral associated cases) is largely unknown and may provide important insights for new therapeutic strategies.MethodsIn this prospective clinical trial (UKCRN11945), we examined cell-mediated immune responses to HPV16 E2, E6 and E7 in peripheral blood using IFN-γ enzyme-linked immunosorbent spot assay. CD56+, CD4+, CD8+ and regulatory T cell frequencies were also discerned by flow cytometry. Fifty-one study participants with oropharyngeal carcinoma were recruited. Control subjects were those undergoing tonsillectomy for benign disease. All patients were treated with curative intent by radiotherapy ± chemotherapy. Disease-specific survival was investigated by multivariate analysis.ResultsHPV16 DNA was detected in 41/51 of the OPSCC participants. T cell responses against HPV16 E6 or E7 peptides were detected in 33/51 evaluable patients, respectively and correlated with HPV status. Matched pre- and post-treatment T cell responses were available for 39/51 OPSCC cases. Within the whole cohort, elevated post-treatment CD8+ response to HPV16 E7 correlated with longer disease free survival (multivariate DFS p < 0.03). Within the HPV + OPSCC cohort, a significant increase in regulatory T cells (p < 0.02) was noted after treatment.ConclusionsThis is the first study to provide survival data in OPSCC stratified by cell-mediated immune response to HPV16 peptides. Within the HPV16+ OPSCC cohort, enhanced immunoreactivity to antigen E7 was linked to improved survival. An increase in regulatory T cell frequencies after treatment may suggest that immunosuppression can contribute to a reduced HPV-specific cell-mediated response.
http://ift.tt/2dhoGju
Impact of cisplatin dose intensity on human papillomavirus-related and -unrelated locally advanced head and neck squamous cell carcinoma
Source:European Journal of Cancer, Volume 67
Author(s): Anna Spreafico, Shao Hui Huang, Wei Xu, Roberta Granata, Chen-Shin Liu, John N. Waldron, Eric Chen, Jolie Ringash, Andrew Bayley, Kelvin K.W. Chan, Andrew J. Hope, John Cho, Albiruni A.R. Razak, Aaron Hansen, Raymond Jang, Bayardo Perez-Ordonez, Ilan Weinreb, Paolo Bossi, Ester Orlandi, Lisa F. Licitra, Yuyao Song, Brian O'Sullivan, Lillian L. Siu, John Kim
AimThe aim is to evaluate the impact of cisplatin dose modification on outcomes of human papillomavirus (HPV)-related (HPV+) and HPV-unrelated (HPV−) locally advanced head and neck cancer (LAHNC) treated with chemoradiotherapy (CRT).Patients and methodsA pooled analysis was conducted of stage III/IV oropharyngeal cancer (OPC), carcinoma of unknown primary (CUP) and laryngo-hypopharyngeal cancer (LHC) patients treated with single-agent cisplatin CRT in 2000–2012 from two tertiary academic cancer centres. HPV status was determined by p16 staining and/or in situ hybridisation. LHC was assumed to be HPV−. Unknown HPV status OPC/CUPs were excluded. Overall survival (OS) was calculated. Multivariable analysis (MVA) evaluated the impact of cisplatin dose intensity on survival for HPV+ and HPV− cohorts separately.ResultsA total of 404 HPV+ and 255 HPV− LAHNC (481 OPC, 18 CUP, 160 LHC) patients were included. Median follow-up was 4.3 (0.5–11.9) years. Three-year OS for cisplatin <200, =200, and >200 mg/m2 subgroups were 52%, 60%, and 72% (P = 0.001) for the HPV− and 91%, 90%, and 91% (P = 0.30) for the HPV+ patients. MVA confirmed a survival benefit with cisplatin >200 mg/m2 for the HPV− (hazard ratio [HR] 0.5, 95% confidence interval [CI]: 0.3–0.7, P < 0.001) but not for HPV+ (HR 0.6, 95% CI: 0.4–1.1, P = 0.104). There was a superior OS trend in the HPV+ T4 or N3 high-risk subset (N = 107) with cisplatin >200 mg/m2 (HR 0.5, 95% CI: 0.2–1.1, P = 0.07).ConclusionsA survival benefit of cisplatin dose >200 mg/m2 is evident for HPV− LAHNC patients, but not for HPV+ cohort overall, although the T4 or N3 subset may benefit from a higher cumulative cisplatin dose.
http://ift.tt/2cUk6fH
Effects of time interval between primary melanoma excision and sentinel node biopsy on positivity rate and survival
Source:European Journal of Cancer, Volume 67
Author(s): Charlotte M.C. Oude Ophuis, Alexander C.J. van Akkooi, Piotr Rutkowski, Christiane A. Voit, Joanna Stepniak, Nicole S. Erler, Alexander M.M. Eggermont, Michel W.J.M. Wouters, Dirk J. Grünhagen, Cornelis (Kees) Verhoef
BackgroundSentinel node biopsy (SNB) is essential for adequate melanoma staging. Most melanoma guidelines advocate to perform wide local excision and SNB as soon as possible, causing time pressure.ObjectiveTo investigate the role of time interval between melanoma diagnosis and SNB on sentinel node (SN) positivity and survival.MethodsThis is a retrospective observational study concerning a cohort of melanoma patients from four European Organization for Research and Treatment of Cancer Melanoma Group tertiary referral centres from 1997 to 2013. A total of 4124 melanoma patients underwent SNB. Patients were selected if date of diagnosis and follow-up (FU) information were available, and SNB was performed in <180 d. A total of 3546 patients were included. Multivariable logistic regression and Cox regression analyses were performed to investigate how baseline characteristics and time interval until SNB are related to positivity rate, disease-free survival (DFS) and melanoma-specific survival (MSS).FindingsMedian time interval was 43 d (interquartile range [IQR] 29–60 d), and 705 (19.9%) of 3546 patients had a positive SN. Sentinel node positivity was equal for early surgery (≤43 d) versus late surgery (>43 d): 19.7% versus 20.1% (p = 0.771). Median FU was 50 months (IQR 24–84 months). Sentinel node metastasis (hazard ratio [HR] 3.17, 95% confidence interval [95% CI] 2.53–3.97), ulceration (HR 1.99, 95% CI 1.58–2.51), Breslow thickness (HR 1.06, 95% CI 1.04–1.08), and male gender (HR 1.58, 95% CI 1.26–1.98) (all p < 0.00001) were independently associated with worse MSS and DFS; time interval was not.InterpretationNo effect of time interval between melanoma diagnosis and SNB on 5-year survival or SN positivity rate was found for a time interval of up to 3 months. This information can be used to counsel patients and remove strict time limits from melanoma guidelines.
http://ift.tt/2dd5irJ
Cyclin A1 expression and paclitaxel resistance in human ovarian cancer cells
Source:European Journal of Cancer, Volume 67
Author(s): Kuan-Chun Huang, Junzheng Yang, Michelle C. Ng, Shu-Kay Ng, William R. Welch, Michael G. Muto, Ross S. Berkowitz, Shu-Wing Ng
BackgroundThe development of intrinsic and acquired resistance to antineoplastic agents is a major obstacle to successful chemotherapy in ovarian cancers. Identification and characterisation of chemoresponse-associated biomarkers are of paramount importance for novel therapeutic development.MethodsGlobal RNA expression profiles were obtained by high-throughput microarray analysis. Cell cycle, proliferation rate, and paclitaxel sensitivity of ovarian cancer cells harbouring cyclin A1-inducible expression construct were compared with and without tetracycline induction, as well as when the cyclin A1 expression was suppressed by short inhibiting RNA (siRNA). Cellular senescence was evaluated by β-galactosidase activity staining.ResultsGlobal RNA expression profiling and subsequent correlation studies of gene expression level and drug response has identified that elevated expression of cyclin A1 (CCNA1) was significantly associated with cellular resistance to paclitaxel, doxorubicin and 5-fluorouracil. The role of cyclin A1 in paclitaxel resistance was confirmed in ovarian cancer cells that harbour an inducible cyclin A1 expression construct, which showed reduced paclitaxel-mediated growth inhibition and apoptosis when cyclin A1 expression was induced, whereas downregulation of cyclin A1 expression in the same cell lines using cyclin A1-specific siRNAs sensitised the cells to paclitaxel toxicity. However, ovarian cancer cells with ectopic expression of cyclin A1 demonstrated slowdown of proliferation and senescence-associated β-galactosidase activity.ConclusionsOur profiling and correlation studies have identified cyclin A1 as one chemoresistance-associated biomarker in ovarian cancer. The results of the characterisation studies suggest that cyclin A1 functions as an oncogene that controls proliferative and survival activities in tumourigenesis and chemoresistance of ovarian cancer.
http://ift.tt/2dhpftr
Scholar : These new articles for Bulletin of Spanish Studies are available online
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Scholar : These new articles for Aging & Mental Health are available online
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Development of long-term antimicrobial poly(methyl methacrylate) by incorporating mesoporous silica nanocarriers
Publication date: Available online 23 September 2016
Source:Dental Materials
Author(s): Jung-Hwan Lee, Ahmed El-Fiqi, Jeong-Ki Jo, Dong-Ae Kim, Si-Chul Kim, Soo-Kyung Jun, Hae-Won Kim, Hae-Hyoung Lee
ObjectivePoly(methyl methacrylate) (PMMA) used as removable denture bases or orthodontic appliances has relatively poor antimicrobial properties, which accelerate oral infection and induce unfavorable odors. Mesoporous silica nanoparticles (MSNs) have been highlighted as a potential additive to overcome this issue because of their drug-loading capacity. Here, we present the long-term antimicrobial effect of MSN-incorporated PMMA with drug-loading capacity.MethodsAfter the MSNs were characterized, MSN incorporation into chemically activated PMMA (0.5, 1, 2.5 or 5wt%) relative to the methyl methacrylate powder by mass was fabricated into a rectangular specimen (1.4×3.0×19.0mm) for a 3-point flexural test at a speed of 1mm/min or a disk (∅=11.5mm and d=1.5mm) for investigation of its antimicrobial effects.ResultsA typical spherical morphology with a well-ordered mesoporous structure of the MSNs was visualized and is beneficial for loading drugs and combining in matrixes. Among the tested levels of MSN incorporation in PMMA (0.5, 1, 2.5 or 5wt%), only 5wt% decreased the flexural strength (p<0.05), whereas the flexural modulus was not significantly decreased (p>0.05). The surface roughness and surface energy were increased with 2.5wt% or 5wt% incorporation. An anti-adherent effect against Candida albicans and Streptococcus oralis after 1h of attachment was only observed with 2.5 and 5wt% incorporation compared to a lack of MSNs (p<0.05). A long-term antimicrobial effect was observed for 2 weeks with 2.5wt% MSN-incorporated PMMA when amphotericin B was loaded into the MSNs on the PMMA surface.SignificanceThe long-term antimicrobial performance after loading amphotericin B into the MSN-incorporated PMMA suggests the potential clinical usefulness of MSN-incorporated PMMA resin.
Graphical abstract
http://ift.tt/2doTzDb
New acid BisGMA analogs for dental adhesive applications with antimicrobial activity
Publication date: Available online 23 September 2016
Source:Dental Materials
Author(s): Violeta Melinte, Tinca Buruiana, Andreea Chibac, Mihai Mares, Horia Aldea, Emil C. Buruiana
ObjectiveTo achieve bisphenol A glycerolate dimethacrylate (BisGMA) analogs with reduced viscosity to be used in the formulation of dental adhesives containing biocidal components.MethodsA series of low-viscosity BisGMA derivatives (η: 39–12Pas) modified with 30, 60 and, respectively 80mol% carboxylic acid units were synthesized and characterized. Hydrogen bonding interactions in our monomers, the photopolymerization behavior and implicitly the conversion degree (DC) for some experimental adhesive formulations containing acid-modified BisGMA, commercial BisGMA (only in F1–F3), triethyleneglycol dimethacrylate and 2-hydroxyethyl methacrylate were examined by FTIR spectroscopy. The water effects on the photocrosslinked networks together with the flexural strength/modulus were also investigated. The adhesive penetration into the dentin surface was surveyed by SEM analysis, and the antimicrobial activity triggered by the incorporation of 0.5wt% AgNO3, 10wt% zinc methacrylate or 1wt% triclosan methacrylate in selected adhesive formulations on the growth of Streptococcus mutans and Candida albicans strains was evidenced.ResultsThe contribution of the hydrogen bonding interactions was found to be lower in BisGMA derivatives than in non-modified BisGMA, and the DC varied between 56.5 (F6) and 83.7% (F1) compared with a control formulation based on BisGMA:TEGDMA (DC=58.2%). The flexural strength and flexural modulus varied in the range 33.7MPa (F6)–54.4MPa (F8)MPa and 0.64 (F6)–1.43 (F8)GPa, respectively. SEM observation of adhesive-dentin interface revealed the formation of resin tags for the carboxyl-containing adhesive, while for the control adhesive they are hardly formed. Also, the microorganism development was inhibited, the proposed materials displaying antimicrobial activity.SignificanceThe experimental formulations based on carboxyl-functionalized BisGMA exhibit a similar or even improved behavior over control sample, suggesting their potential applicability as antimicrobial dental adhesives.
Graphical abstract
http://ift.tt/2doSwTy
Fatigue behavior of resin-modified monolithic CAD–CAM RNC crowns and endocrowns
Source:Dental Materials
Author(s): G.T. Rocca, P. Sedlakova, C.M. Saratti, R. Sedlacek, L. Gregor, N. Rizcalla, A.J. Feilzer, I. Krejci
ObjectiveTo evaluate the influence of different types of modifications with resin on fatigue resistance and failure behavior of CAD–CAM resin nano ceramic (RNC) restorations for maxillary first premolars.MethodsSixty standardized resin composite root dies received CAD–CAM RNC endocrowns (n=30) and crowns (n=30) (Lava Ultimate, 3M Espe). Restorations were divided into six groups: full anatomic endocrowns (group A) and crowns (group D), buccal resin veneered endocrowns (group B) and crowns (group E) and buccal resin veneered endocrowns (group C) and crowns (group F) with a central groove resin filling. A nano-hybrid resin composite was used to veneer the restorations (Filtek Supreme, 3M Espe). All specimens were first submitted to thermo-mechanical cyclic loading (1.7Hz, 49N, 600000 cycles, 1500 thermo-cycles) and then submitted to cyclic isometric stepwise loading (5Hz) until completion of 105000 cycles or failure after 5000 cycles at 200N, followed by 20000 cycles at 400N, 600N, 800N, 1000N and 1200N. In case of fracture, fragments were analyzed using SEM and modes of failure were determined. Results were statistically analyzed by Kaplan–Meier life survival analysis and log rank test (p=0.05).ResultsThe differences in survival between groups were not statistically significant, except between groups D and F (p=0.039). Endocrowns fractured predominantly with a mesio-distal wedge-opening fracture (82%). Partial cusp fractures were observed above all in crowns (70%). Analysis of the fractured specimens revealed that the origin of the fracture was mainly at the occlusal contact points of the stepwise loading.SignificanceVeneering of CAD–CAM RNC restorations has no influence on their fatigue resistance except when monolithic crowns are modified on their occlusal central groove.
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Porcelain bonding to novel Co–Cr alloys: Influence of interfacial reactions on phase stability, plasticity and adhesion
Source:Dental Materials
Author(s): Kai Chun Li, LeYing Tran, David J. Prior, J. Neil Waddell, Michael V. Swain
ObjectiveThe objective of the present study was to determine the hardness and adhesion strength at the porcelain to alloy interface.Methods15 bi-layer porcelain veneered Co–Cr specimens of each alloy group [cast, powder metallurgy (PM), CAD/CAM(CC)] were manufactured. 12 bi-layered specimens were tested using four-point bend strain energy release rate adhesion test. One before and after porcelain firing specimen of each alloy group were nano-indented at the bulk and metal-porcelain interface to determine the mechanical properties. Electron backscatter diffraction was used to determine the microstructure and phase of the indented areas.ResultsThe results obtained from the four-point bend strain energy release rate test indicated highest adhesion energy of 92.15J/m2 observed in the CC produced Co–Cr alloy. This was followed by the PM alloy with an adhesion energy of 62.24J/m2 and cast alloy with an adhesion energy of 42.83J/m2. All comparisons of adhesion energy between the three alloys were found to be statistically significant (p<.05). Nano-indentation test indicated higher hardness values of 4.6–6.1GPa at the metal-porcelain interface compared to the bulk, which had hardness values of 3.1–3.9GPa.SignificanceThe adhesion of the alloy to porcelain was found to be inversely related to the hardness of the interfacial layer at the alloy surface. Lower interfacial hardness was found to be accompanied with higher adhesion energy due to the additional plastic energy consumed during crack propagation along the more ductile interface region of the alloy.
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Evaluation of monomer leaching from a resin cement through dentin by a novel model
Source:Dental Materials
Author(s): C. Kerezoudi, C. Gogos, V. Samanidou, D. Tziafas, G. Palaghias
ObjectiveTo evaluate the elution of HEMA, BPA, UDMA and BisGMA from a conventional resin cement (Multilink Automix®, Ivoclar Vivadent) through human dentin, under constant positive pulpal pressure.MethodsTen human dentin disks (n=10) were adjusted in a new testing device and transparent glass slabs were luted with Multilink Automix® resin cement, following manufacturer's instructions, under a steady pressure of 25N. The device was filled with Ringer's solution. At 5min, 20min, 1h, 2h, 21h, 3 days, 7 days, 10days and 21days time intervals, the whole eluate was retrieved from each one of the ten specimens and then, the specimens were refilled with fresh Ringer's solution. The eluates were analyzed by High Performance Liquid Chromatography (HPLC).ResultsHEMA was detected in the eluate of all of the specimens, from 5min until 10 days. At four of the specimens, HEMA was also detected in the 21days eluate at very low concentrations. BPA, UDMA and BisGMA were not detected at any eluate. An unknown compound was also detected at 4.4min.SignificanceThe concentrations of HEMA that enabled to diffuse from Multilink Automix® cement in an aqueous solution, through a dentin barrier, did not reach toxic levels and BPA, UDMA and BisGMA were not detected at all.
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High strength and toughness in chromatic polymer-infiltrated zirconia ceramics
Source:Dental Materials
Author(s): Jing Li, Ben-cang Cui, Yuan-hua Lin, Xu-liang Deng, Ming Li, Ce-wen Nan
ObjectiveTo evaluate the microstructure and mechanical behavior of polymer-infiltrated zirconia ceramics as a function of Fe2O3 concentration (0–0.3mol%).MethodsPolymer-infiltrated zirconia ceramics with different concentrations of Fe2O3 were prepared by infiltration and polymerization. XRD was employed to determine phase structure. The microstructure and fracture mechanism was observed by SEM. Flexural strength and fracture toughness were measured by three-point bending method and single-edge-notched beam method, respectively. Data were analyzed by Weibull distribution. A nanoindentation system was employed to determine elastic modulus and hardness.ResultsWith increasing content of Fe2O3, the flexural strength, fracture toughness, elastic modulus and hardness are all greatly enhanced and the chromatic behavior also improves significantly. As a tradeoff made between strength and elastic modulus, specimen containing 0.2mol% Fe2O3 is found to be the better one, with flexural strength and fracture toughness values being 336.8MPa and 3.91MPam1/2, respectively. Moreover, it maintains a relatively low elastic modulus of 88.2GPa and a moderate hardness of 4.8GPa, close to those of natural enamel.SignificanceThis polymer-infiltrated zirconia ceramic material is a dental material of biomimetic chromatic and mechanical properties.
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Shrinkage behaviors of dental composite restorations—The experimental–numerical hybrid analysis
Source:Dental Materials
Author(s): Shu-Fen Chuang, Pin-Sheng Huang, Terry Yuan-Fang Chen, Lo-Hao Huang, Ko-Chih Su, Chi-Han Chang
ObjectivesTo investigate the effects of light curing protocols on the shrinkage behaviors, contraction stress, and microleakage in composite restorations by an experimental–numerical hybrid analysis.MethodsThree groups of human molars were collected to receive different light-curing protocols: vertical or oblique curing at regular intensity, and vertical curing at reduced intensity. For each tooth, the composite fillings were consecutively placed under unbonded and bonded states, and their shrinkage behaviors were examined with a digital image correlation (DIC) technique. The strains of the unbonded restorations were input into two finite element analysis (FEA) models with settings of the composite as either homogeneous or hardened along polymerization gradients. The preliminary solutions were verified by their individual deformations in the bonded restorations. The interfacial microleakage of restorations was also determined by micro-CT scanning and compared with the FEA results.ResultsThe bonded restorations showed centripetal shrinkage patterns with greater downward displacements than their unbonded restorations. Vertical curing at regular intensity caused the greatest shrinkage strain, contraction stress, and microleakage among the three protocols. Low-intensity curing reduced overall shrinkage strain and displacements at cervical margin, but did not prevent the formation of microleakage. Oblique curing caused asymmetric shrinkage with the tooth-shielded side revealing less deformation. Setting the polymerization-dependent elastic moduli of the composite enhanced the reliability of FEA.SignificanceThis hybrid analysis comprehensively examined the polymerization shrinkage behaviors. Both the light intensity and direction affect the shrinkages and contraction stress. Oblique curing decreases shrinkage due to the attenuated irradiation by tooth-shielding rather than modulations of shrinkage direction.
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Novel bioactive nanocomposite for Class-V restorations to inhibit periodontitis-related pathogens
Source:Dental Materials
Author(s): Lin Wang, Mary A.S. Melo, Michael D. Weir, Xianju Xie, Mark A. Reynolds, Hockin H.K. Xu
ObjectivesThe occurrence of tooth root caries is increasing as the world population ages and tooth retention in seniors increases. Class V restorations with subgingival margins are difficult to clean and often lead to periodontitis. The objectives of this study were to develop a Class V composite containing dimethylaminohexadecyl methacrylate (DMAHDM) and nanoparticles of amorphous calcium phosphate (NACP), and investigate mechanical properties and the inhibition of six species of periodontitis-related biofilms for the first time.MethodsEthoxylated bisphenol A dimethacrylate (EBPADMA) and pyromellitic glycerol dimethacrylate (PMGDM) were mixed at 1:1 mass ratio to form the resin matrix. DMAHDM, NACP, and glass particles were incorporated at 3%, 20% and 50% by mass, respectively. Six species were tested: Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum and Enterococcus faecalis. Colony-forming units (CFU), live/dead assay, biomass via crystal violet staining, and polysaccharide production by biofilms were determined on composites.ResultAdding 3% DMAHDM to composite did not affect the flexure strength and elastic modulus (p>0.1). For all six species of periodontal pathogens, the DMAHDM composite had biofilm CFU nearly three orders of magnitude less than that without DMAHDM. The killing efficacy of DMAHDM composite against the six species was: E. faecalis<F. nucleatum<P. nigrescens=P. intermedia<A. actinomycetemcomitans<P. gingivalis. Biofilm biomass and polysaccharide were also greatly reduced via DMAHDM (p<0.05).SignificanceThe novel nanocomposite containing DMAHDM and NACP showed strong inhibiting effect against all six species of periodontitis-related pathogens. This composite is promising for Class V restorations to restore root caries and combat periodontitis.
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Interaction between LPS and a dental resin monomer on cell viability in mouse macrophages
Source:Dental Materials
Author(s): Helmut Schweikl, Matthias Widbiller, Stephanie Krifka, Johannes Klement, Christine Petzel, Carola Bolay, Karl-Anton Hiller, Wolfgang Buchalla
ObjectiveLipopolysaccharide (LPS) from cariogenic microorganisms and resin monomers like HEMA (2-hydroxyethyl methacrylate) included in dentin adhesive are present in a clinical situation in deep dentinal cavity preparations. Here, cell survival, expression of proteins related to redox homeostasis, and viability of mouse macrophages exposed to LPS and HEMA were analyzed with respect to the influence of oxidative stress.MethodsCell survival of RAW264.7 mouse macrophages was determined using a crystal violet assay, protein expression was detected by Western blotting, and HEMA- or LPS-induced apoptosis (cell viability) was analyzed by flow cytometry. Cells were exposed to HEMA (0–8mM), LPS (0.1μg/ml) or combinations of both substances for 24h. The influence of mitogen-activated protein kinases (MAPK) was analyzed using the specific inhibitors PD98059 (ERK1/2), SB203580 (p38) or SP600125 (JNK), and oxidative stress was identified by the antioxidant N-acetylcysteine (NAC).ResultsCell survival was reduced by HEMA. LPS, however, increased cell survival from 29% in cultures exposed to 8mM HEMA, to 46% in cultures co-exposed to 8mM HEMA/LPS. Notably, LPS-induced apoptosis was neutralized by 4–6mM HEMA but apoptosis caused by 8mM HEMA was counteracted by LPS. Expression of NOS (nitric oxide synthase), p47phox and p67phox subunits of NADPH oxidase, catalase or heme oxygenase (HO-1) was associated with HEMA- or LPS-induced apoptosis. While no influence of MAPK was detected, NAC inhibited cytotoxic effects of HEMA.SignificanceHEMA- and LPS-triggered pathways may induce apoptosis and interfere with physiological tissue responses as a result of the differential formation of oxidative stress.
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Co–Cr dental alloys induces cytotoxicity and inflammatory responses via activation of Nrf2/antioxidant signaling pathways in human gingival fibroblasts and osteoblasts
Source:Dental Materials
Author(s): Eun-Cheol Kim, Myo-Kyoung Kim, Richard Leesungbok, Suk-Won Lee, Su-Jin Ahn
ObjectiveAlthough cobalt–chromium (Co–Cr) dental alloys are routinely used in prosthodontics, the biocompatibility of Co–Cr alloys is controversial. The aims of the present study were to investigate the effects of Co–Cr alloys on human gingival fibroblasts (HGF) and osteoblasts in an in vitro model as well as their potential molecular mechanisms, focusing on NF-E2-related factor 2 (Nrf2) pathways.MethodsCells were directly seeded on prepared Co–Cr alloy discs (15.0mm diameter, 1.0mm thickness) or indirectly treated with Co–Cr alloy located at the bottom of an insert well and incubated for 3 days. Cytotoxicity and reactive oxygen species (ROS) production was evaluated by MTS assay and flow cytometry, respectively. Protein and mRNA levels were determined by Western blotting and RT-PCR analysis, respectively.ResultsCell viability and flow cytometric assay demonstrated that the Co–Cr alloy was cytotoxic to HGFs and osteoblasts, and significantly increased ROS production. In addition, the Co–Cr alloys upregulated pro-inflamamtory cytokines (TNF-α, IL-1β, IL-6, and IL-8) and increased levels of various inflammatory mediators (iNOS derived nitrite oxide, and COX-2-derived PGE2) in both cells. A mechanistic study showed that Co–Cr alloys activates the NRF2 pathway and up-regulate antioxidant enzymes including heme oxygenase-1 (HO-1). Co–Cr alloys activated JAK2/STAT3, p38/ERK/JNK MAPKs and NF-κB signaling pathways. Furthermore, antioxidants (resveratrol and NAC) and HO-1 inhibitor (SnPP) significantly inhibited the production of ROS and inflammatory mediators, as well as the activation of NF-κB signaling in Co–Cr alloy stimulated HGFs and osteoblasts.SignificanceThis study is the first to show that Co–Cr alloys exert cytotoxic and inflammatory effects via activation of Nrf2/ARE signaling and up-regulation of downstream HO-1, which could represent candidate targets for the regulation of inflammatory responses to Co–Cr alloys.
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Ειδοποίηση Μελετητή:[ ωτα ] [HTML] Gender, identity and material: Film screening C Brand - 2017 ftypM4V *M4V M4A mp42isom*a┌moovlmvhd...
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Publication date: September 2017 Source: Free Radical Biology and Medicine, Volume 110 Author(s): Lucía Fernández-del-Río, Anish Nag, Elen...
