bluuebunny/crossref_metadata_2025 huggingface dataset:
Prediction of constitutive behaviour of 20CrMnTiH steel under hot deformation conditions
Authors: Chai R X , Xu D H , Guo C
Published: May 2012

Isothermal compression tests are carried out on 20CrMnTiH steel using a Gleeble-1500 thermal simulator in the temperature range of 1223–1423 K and in the strain rate range of 0·01–10 s−1. The flow behaviours of 20CrMnTiH steel are described, which are based on the analysis of true stress–true strain curves. The effects of hot deformation on the microstructure are investigated. The results show that there is a typical dynamic recrystallisation behaviour during deformation. A constitutive model coupling flow stress with strain, strain rate and temperature to 20CrMnTiH steel is proposed using a hyperbolic sinusoidal type equation. In the constitutive equation, the material constants α, n, ln  A and Q are found to be functions of strain. The validity of the constitutive equation is assessed by the correlation coefficient ( r), the average absolute relative error and the mean squared error.
Modulus and strength prediction for natural fibre composites
Authors: Virk A S , Hall W , Summerscales J
Published: May 2012

This paper presents a new micromechanical model for the prediction of the tensile modulus and strength of natural fibre reinforced polymer matrix composites. The model addresses issues linked to the statistical variation inherent in fibre reinforcements extracted from plants. The new model introduces a fibre area correction factor (FACF). Modulus and strength are estimated and compared to experimental data for a jute–epoxy composite. The predictions of tensile modulus and strength using the FACF show improvements over those from other micromechanical models presented in the literature.
Modelling and simulation of A segregates in steel castings using thermal criterion function Part I – Background and validation
Authors: Kotas P , Hattel J H
Published: May 2012

The present paper is the first out of two papers in which thermal criteria for modelling and optimising, i.e. minimising, the formation of A segregates are investigated. One specific thermal criterion has been incorporated into a transient three-dimensional thermal fluid model inside a commercial simulation software package. It is then used for predicting A segregates inside a large steel casting, i.e. a forging ram. In part I, experimental data obtained from a foundry serve to validate the given criterion and to evaluate the critical value for A segregate initiation for one alloy composition on the forging ram. In part II, the criterion forms the basis of shape optimisation of the original casting layout for the ram. More specifically, unknown optimal shapes and sizes of the top riser and chills are sought by means of autonomous optimisation to establish a better solidification pattern, which would eliminate the likelihood of centreline porosity and A segregates.
Investigation of embrittlement of step cooling heat treatment on pressure vessel steel
Authors: Li Y L , Fu L M , Hu Y , Zhang H Q , Chen J B , Li J F
Published: May 2012

The effects of thermal aging and step cooling embrittlement on the impact toughness of a reactor pressure vessel steel SA533B quenched and tempered (QT) with and without post-weld heat treatment (PWHT) have been studied. Charpy impact testings were conducted on the aged plates at 350°C for 5000 h to evaluate whether the embrittlement was induced by step cooling heat treatment. The results show that thermal aging increases the ductile–brittle transition temperature in both QT and PWHT states but dramatically decreases the upper shelf energy in QT state and has less effects on the PWHT state. By comparing the correlation between thermal aging embrittlement and step cooling embrittlement for both QT and PWHT states in steel, it is found that the step cooling heat treatment can obviously promote further embrittlement of the base metal in QT state but has little influence on the impact toughness in PWHT and thermal aged state. Further analysis indicates that the step cooling heat treatment cannot promote steel embrittlement at some heat treatment states. Finally, a new method is proposed to evaluate the degree of step cooling embrittlement of the pressure vessel steel.
Influence of indenter shape on DLC film failure during multiple load cycle nanoindentation
Authors: Faisal N. H. , Ahmed R. , Fu Y. Q. , Elakwah Y. O. , Alhoshan M.
Published: May 2012

The aim of the present investigation is to understand the localised failure mechanism of diamond-like carbon (DLC) film during multiple load cycle nanoindentation. The DLC film investigated was 500 nm thick sputter coated on Si (100) wafer of 500 μm thickness. Multiple load cycle nanoindentation tests under diamond Berkovich and conical indenters were performed using a calibrated NanoTest at five different load ranges between 0·1 and 500 mN. Test results indicated forward deviation, no deviation and backward deviation of the force–displacement profile, which provided some insights to the mechanisms of localised film failure. During backward deviation, film failure starts from interfacial delamination. This was observed for a conical indenter in a particular load range (1–10 mN). An elastic finite element model during nanoindentation loading indicated that this was caused by the location of maximum stress near the interface. Forward depth deviation was observed for conical and Berkovich indenter at all the other load ranges.
Effect of short duration tempering on the microstructure and mechanical properties of a continuously annealed dual phase steel
Authors: Mukherjee M , Chintha A R , Raj A , Pathak P , Haldar A
Published: May 2012

The effect of short duration tempering on the microstructure and mechanical properties of a continuously annealed dual phase steel was investigated using techniques like electron microscopy, dilatometry and thermodynamic calculations. It was found that a complex interplay of phenomena like tempering of martensite, quench aging of ferrite and recovery of the overall structure was responsible for the change in mechanical properties recorded.
Fabrication and characterisation of nickel coated Ni-NCZ (nickel coated ZrO2) composite coating
Authors: Arghavanian R , Parvini Ahmadi N , Yazdani S , Bostani B
Published: May 2012

For the first time, electroless nickel plated ZrO2 (Ni-NCZ) particles were used for the co-electrodeposition of Ni-NCZ composite coating. Optical microscope, SEM and X-ray diffraction studies showed that Ni-NCZ has a rough surface with a smaller Ni crystallite size than Ni-ZrO2 due to the conductive properties of NCZ particles, which provide more nucleation sites for Ni clusters. The energy dispersive X-ray spectroscopy measurement results showed that Ni-NCZ has more co-electrodeposited particles than Ni-ZrO2. This is due to the more positive zeta potential of NCZ particles compared to that of ZrO2. The microhardness measurements demonstrated that the Ni-NCZ composite coating has a higher microhardness than Ni-ZrO2 due to the higher amounts of co-electrodeposited particles and lower crystallite size. Electrochemical impedance spectroscopy and potentiodynamic polarisation test showed that the corrosion resistance of Ni-NCZ is higher than that of Ni-ZrO2.
Antifog coating for bronchoscope lens
Authors: Leonard R L , Terekhov A Y , Thompson C , Erck R A , Johnson J A
Published: May 2012

Current bronchoscopes suffer from fogging and the adhesion of mucus plugs to the lens. A doped diamond-like carbon film was developed as a possible solution to this problem. A silicon monoxide dopant was found to produce a film that was transparent, hydrophilic and stable in simulated body fluid (SBF) and therefore showed potential as an antifogging coating. The film was deposited by pulsed laser deposition and characterised by Raman spectroscopy, atomic force microscopy, spectrophotometry and contact angle measurements. Root mean square surface roughness was found to be <1 nm. The unique characteristics of these films include production without secondary processing, a lowest contact angle of 25° and stability in SBF for several months combined with transparency.
CCR2 recruits an inflammatory macrophage subpopulation critical for angiogenesis in tissue repair
Authors: Willenborg Sebastian , Lucas Tina , van Loo Geert , Knipper Johanna A. , Krieg Thomas , Haase Ingo , Brachvogel Bent , Hammerschmidt Matthias , Nagy Andras , Ferrara Napoleone , Pasparakis Manolis , Eming Sabine A.
Published: May 2012

Monocytes/macrophages are critical in orchestrating the tissue-repair response. However, the mechanisms that govern macrophage regenerative activities during the sequential phases of repair are largely unknown. In the present study, we examined the dynamics and functions of diverse monocyte/macrophage phenotypes during the sequential stages of skin repair. By combining the analysis of a new CCR2-eGFP reporter mouse model with conditional mouse mutants defective in myeloid cell–restricted CCR2 signaling or VEGF-A synthesis, we show herein that among the large number of inflammatory CCR2+Ly6C+ macrophages that dominate the early stage of repair, only a small fraction strongly expresses VEGF-A that has nonredundant functions for the induction of vascular sprouts. The switch of macrophage-derived VEGF-A during the early stage of tissue growth toward epidermal-derived VEGF-A during the late stage of tissue maturation was critical to achieving physiologic tissue vascularization and healing progression. The results of the present study provide new mechanistic insights into CCR2-mediated recruitment of blood monocyte subsets into damaged tissue, the dynamics and functional consequences of macrophage plasticity during the sequential repair phases, and the complementary role of macrophage-derived VEGF-A in coordinating effective tissue growth and vascularization in the context of tissue-resident wound cells. Our findings may be relevant for novel monocyte-based therapies to promote tissue vascularization.
Genome wide response to dietary tetradecylthioacetic acid supplementation in the heart of Atlantic Salmon (Salmo salar L)
Authors: Grammes Fabian , Rørvik Kjell-Arne , Thomassen Magny S , Berge Rolf K , Takle Harald
Published: May 2012

Background

Under-dimensioned hearts causing functional problems are associated with higher mortality rates in intensive Atlantic salmon aquaculture. Previous studies have indicated that tetradecylthioacetic acid (TTA) induces cardiac growth and also stimulates transcription of peroxisome proliferator activated receptors (PPAR)αandβin the Atlantic salmon heart. Since cardiac and transcriptional responses to feed are of high interest in aquaculture, the objective of this study was to characterize the transcriptional mechanisms induced by TTA in the heart of Atlantic salmon.

Results

Atlantic salmon were kept at sea for 17 weeks. During the first 8 weeks the fish received a TTA supplemented diet. Using microarrays, profound transcriptional effects were observed in the heart at the end of the experiment, 9 weeks after the feeding of TTA stopped. Approximately 90% of the significant genes were expressed higher in the TTA group. Hypergeometric testing revealed the over-representation of 35 gene ontology terms in the TTA fed group. The GO terms were generally categorized into cardiac performance, lipid catabolism, glycolysis and TCA cycle.

Conclusions

Our results indicate that TTA has profound effects on cardiac performance based on results from microarray and qRT-PCR analysis. The gene expression profile favors a scenario of ”physiological”lright hypertrophy recognized by increased oxidative fatty acid metabolism, glycolysis and TCA cycle activity as well as cardiac growth and contractility in the heart ventricle. Increased cardiac efficiency may offer significant benefits in the demanding Aquaculture situations.
Toll-like receptor 9polymorphisms are associated with severity variables in a cohort of meningococcal meningitis survivors
Authors: Sanders Marieke S , van Well Gijs TJ , Ouburg Sander , Morré Servaas A , van Furth A Marceline
Published: May 2012

Background

Genetic variation in immune response genes is associated with susceptibility and severity of infectious diseases. Toll-like receptor (TLR) 9 polymorphisms are associated with susceptibility to develop meningococcal meningitis (MM). The aim of this study is to compare genotype distributions of twoTLR9polymorphisms between clinical severity variables in MM survivors.

Methods

We used DNA samples of a cohort of 390 children who survived MM. Next, we determined the genotype frequencies ofTLR9-1237 andTLR9+2848 polymorphisms and compared these between thirteen clinical variables associated with prognostic factors predicting adverse outcome of bacterial meningitis in children.

Results

TheTLR9 -1237 TC and CC genotypes were associated with a decreased incidence of a positive blood culture forNeisseria (N.) meningitidis(p = 0.014, odds ratio (OR) 0.5. 95% confidence interval (CI) 0.3 – 0.9). TheTLR9 +2848 AA mutant was associated with a decreased incidence of a positive blood culture forN. meningitidis(p = 0.017, OR 0.6, 95% CI 0.3 – 0.9). Cerebrospinal fluid (CSF) leukocytes per μL were higher in patients carrying theTLR9 -1237 TC or CC genotypes compared to carriers of the TT wild type (WT) (p = 0.024, medians: 2117, interquartile range (IQR) 4987 versus 955, IQR 3938). CSF blood/glucose ratios were lower inTLR9 -1237 TC or CC carriers than in carriers of the TT WT (p = 0.017, medians: 0.20, IQR 0.4 versus 0.35, IQR 0.5). CSF leukocytes/μL were higher in patients carrying theTLR9 +2848 AA mutant compared to carriers of GG or GA (p = 0.0067, medians: 1907, IQR 5221 versus 891, IQR 3952).

Conclusions

We identified TLR9 genotypes associated with protection against meningococcemia and enhanced local inflammatory responses inside the central nervous system, important steps in MM pathogenesis and defense.
Evolutionary engineering strategies to enhance tolerance of xylose utilizing recombinant yeast to inhibitors derived from spruce biomass
Authors: Koppram Rakesh , Albers Eva , Olsson Lisbeth
Published: May 2012

Background

One of the crucial factors for a sustainable and economical production of lignocellulosic based bioethanol is the availability of a robust fermenting microorganism with high tolerance to inhibitors generated during the pretreatment of lignocellulosic raw materials, since these inhibitors are known to severely hinder growth and fermentation.

Results

A long-term adaptation in repetitive batch cultures in shake flasks using a cocktail of 12 different inhibitors and a long-term chemostat adaptation using spruce hydrolysate were used as evolutionary engineering strategies to improve the inhibitor tolerance in the metabolically engineered xylose utilizing Saccharomyces cerevisiae strain, TMB3400. The yeast was evolved for a period of 429 and 97 generations in repetitive batch cultures and chemostat cultivation, respectively. During the evolutionary engineering in repetitive batch cultures the maximum specific growth rate increased from 0.18 h-1 to 0.33 h-1 and the time of lag phase was decreased from 48 h to 24 h. In the chemostat adaptation, after 97 generations, the specific conversion rates of HMF and furfural were found to be 3.5 and 4 folds higher respectively, compared to rates after three generations. Two evolved strains (RK60-5, RKU90-3) and one evolved strain (KE1-17) were isolated from evolutionary engineering in repetitive batches and chemostat cultivation, respectively. The strains displayed significantly improved growth performance over TMB3400 when cultivated in spruce hydrolysate under anaerobic conditions, the evolved strains exhibited 25 to 38% increase in specific consumption rate of sugars and 32 to 50% increased specific ethanol productivity compared to TMB3400. The evolved strains RK60-5 and RKU90-3 were unable to consume xylose under anaerobic conditions, whereas, KE1-17 was found to consume xylose at similar rates as TMB3400.

Conclusion

Using evolutionary engineering strategies in batch and chemostat cultivations we have generated three evolved strains that show significantly better tolerance to inhibitors in spruce hydrolysate and displayed a shorter time for overall fermentation of sugars compared to the parental strain.
Leukaemia diagnosed as a consequence of haematuria assessment: a case report
Authors: Pisipati Sailaja , Lucas Guy , Pearce Ian
Published: May 2012

Introduction

T-cell prolymphocytic leukaemia is a rare condition that constitutes around 2% of cases of small lymphocytic leukaemia in adults. It follows an aggressive clinical course with a poor prognosis.

Case presentation

We report a 55-year-old male who was diagnosed with T-cell prolymphocytic leukaemia following investigations for microscopic haematuria. Splenomegaly was identified on a plain abdominal radiograph and intravenous urography, thus triggering further investigations and diagnosis.

Conclusion

Our case-report serves to remind us of the need to bear in mind other possible pathologies outwith our own area of expertise when interpreting results of any kind. This is perhaps increasingly important in the current era of increasing sub-specialisation throughout medicine.
Atypical presentation of an oesophageal carcinoma with metastases to the left buttock: a case report
Authors: Smyth Sarah , O'Donnell Mark E , Kumar Susim , Hussain Atiq , Cranley Brian
Published: May 2012

Introduction

Oesophageal carcinomas represent 3% of all cancers in the UK accounting for 7650 new cases per annum. Oesophageal cancer may be associated with swallowing abnormalities, localised mass pressure effects, lymphatic or distant metastatic spread.

Case presentation

We report a 50-year-old man who presented with a painful, enlarging, solid, fixed lesion adjacent to the left buttock with associated dysphagia. Initial endoscopic assessment suggested severe oesophageal inflammation while the lesion in the buttock area was presumed to be a primary soft-tissue neoplasm. However, subsequent histological assessment confirmed a primary oesophageal squamous carcinoma with metastatic spread to the buttock.

Conclusion

We discuss the clinical presentation, investigative modalities, and current therapeutic guidelines associated with this rare metastasis and present other atypical oesophageal musculoskeletal metastases. We emphasise the need to consider all aspects of patient symptomatology during the investigation of any atypical lesion.
Behcet's disease presenting with cerebral vasculitis: a case report
Authors: Ozturk Banu Turgut , Oltulu Refik , Kerimoglu Hurkan , Okudan Suleyman
Published: May 2012

Introduction

Behcet's disease encompasses a group of multisystemic complications secondary to occlusive vasculitis. It presents usually with oral or genital ulcers however, other system involvements may be the first sign as well.

Case presentation

A 26-years-old man admitted to our clinic for his decreased visual acuity. Ophthalmologic examination revealed bilateral vitritis and optic disc swelling. However, the meticulously taken history included other complains like headache and oral ulcers. Further investigation with cranial MRI demonstrated cerebral vasculitis secondary to Behcet's disease.

Conclusion

Behcet's disease may be easy to diagnose when it presents with oral and genital ulcers or panuveitis, however presentation with optic disc swelling may warrant a thorough investigation.
In ovo leptin administration affects hepatic lipid metabolism and microRNA expression in newly hatched broiler chickens
Authors: Hu Yan , Zhang Rui , Zhang Yanhong , Li Jing , Grossmann Roland , Zhao Ruqian
Published: May 2012

Background

A leptin-like immunoreactive substance has been found in chicken eggs and has been implicated in serving as a maternal signal to program offspring growth and metabolism. In the present study, we investigated the effects ofin ovoleptin administration on hatch weight, serum and hepatic concentrations of metabolites and hormones, as well as on the expression of genes involved in hepatic lipid metabolism and the predicted microRNAs (miRNAs) targeting the affected genes. To this end we injected fertile eggs with either 0.5 μg of recombinant murine leptin or vehicle (PBS) before incubation.

Results

Prenatally leptin-exposed chicks showed lower hatch weight, but higher liver weight relative to the body weight, compared to the control group.In ovoleptin treatment increased the hepatic content and serum concentration of leptin in newly hatched chickens. The hepatic contents of triglycerides (TG) and total cholesterol (Tch) were decreased, whereas the serum levels of TG, Tch and apolipoprotein B (ApoB) were increased. The hepatic mRNA expression ofsterol regulator element binding protein 1(SREBP-1c),SREBP-2,hydroxy-3-methylglutaryl coenzyme A reductase(HMGCR) andcholesterol 7α-hydroxylase 1(CYP7A1) was significantly up-regulated, as was the protein content of both SREBP-1c and SREBP-2 in hepatic nuclear extracts of leptin-treated chickens. Moreover, out of 12 miRNAs targetingSREBP-1cand/orHMGCR, five were significantly up-regulated in liver of leptin-treated chicks, includinggga-miR-200bandgga-miR-429, which target bothSREBP-1candHMGCR.

Conclusions

These results suggest that leptinin ovodecreases hatch weight, and modifies hepatic leptin secretion and lipid metabolism in newly hatched broiler chickens, possibly via microRNA-mediated gene regulation.
Relaxin's induction of metalloproteinases is associated with the loss of collagen and glycosaminoglycans in synovial joint fibrocartilaginous explants
Authors: Naqvi Tabassum , Duong Trang T , Hashem Gihan , Shiga Momotoshi , Zhang Qin , Kapila Sunil
Published: May 2012

Diseases of specific fibrocartilaginous joints are especially common in women of reproductive age, suggesting that female hormones contribute to their etiopathogenesis. Previously, we showed that relaxin dose-dependently induces matrix metalloproteinase (MMP) expression in isolated joint fibrocartilaginous cells. Here we determined the effects of relaxin with or without β-estradiol on the modulation of MMPs in joint fibrocartilaginous explants, and assessed the contribution of these proteinases to the loss of collagen and glycosaminoglycan (GAG) in this tissue. Fibrocartilaginous discs from temporomandibular joints of female rabbits were cultured in medium alone or in medium containing relaxin (0.1 ng/ml) or β-estradiol (20 ng/ml) or relaxin plus β-estradiol. Additional experiments were done in the presence of the MMP inhibitor GM6001 or its control analog. After 48 hours of culture, the medium was assayed for MMPs and the discs were analyzed for collagen and GAG concentrations. Relaxin and β-estradiol plus relaxin induced the MMPs collagenase-1 and stromelysin-1 in fibrocartilaginous explants – a finding similar to that which we observed in pubic symphysis fibrocartilage, but not in articular cartilage explants. The induction of these proteinases by relaxin or β-estradiol plus relaxin was accompanied by a loss of GAGs and collagen in joint fibrocartilage. None of the hormone treatments altered the synthesis of GAGs, suggesting that the loss of this matrix molecule probably resulted from increased matrix degradation. Indeed, fibrocartilaginous explants cultured in the presence of GM6001 showed an inhibition of relaxin-induced and β-estradiol plus relaxin-induced collagenase and stromelysin activities to control baseline levels that were accompanied by the maintenance of collagen or GAG content at control levels. These findings show for the first time that relaxin has degradative effects on non-reproductive synovial joint fibrocartilaginous tissue and provide evidence for a link between relaxin, MMPs, and matrix degradation.
Identification of arthritis-related gene clusters by microarray analysis of two independent mouse models for rheumatoid arthritis
Authors: Fujikado Noriyuki , Saijo Shinobu , Iwakura Yoichiro
Published: May 2012

Rheumatoid arthritis (RA) is an autoimmune disease affecting approximately 1% of the population worldwide. Previously, we showed that human T-cell leukemia virus type I-transgenic mice and interleukin-1 receptor antagonist-knockout mice develop autoimmunity and joint-specific inflammation that resembles human RA. To identify genes involved in the pathogenesis of arthritis, we analyzed the gene expression profiles of these animal models by using high-density oligonucleotide arrays. We found 1,467 genes that were differentially expressed from the normal control mice by greater than threefold in one of these animal models. The gene expression profiles of the two models correlated well. We extracted 554 genes whose expression significantly changed in both models, assuming that pathogenically important genes at the effector phase would change in both models. Then, each of these commonly changed genes was mapped into the whole genome in a scale of the 1-megabase pairs. We found that the transcriptome map of these genes did not distribute evenly on the chromosome but formed clusters. These identified gene clusters include the major histocompatibility complex class I and class II genes, complement genes, and chemokine genes, which are well known to be involved in the pathogenesis of RA at the effector phase. The activation of these gene clusters suggests that antigen presentation and lymphocyte chemotaxisis are important for the development of arthritis. Moreover, by searching for such clusters, we could detect genes with marginal expression changes. These gene clusters include schlafen and membrane-spanning four-domains subfamily A genes whose function in arthritis has not yet been determined. Thus, by combining two etiologically different RA models, we succeeded in efficiently extracting genes functioning in the development of arthritis at the effector phase. Furthermore, we demonstrated that identification of gene clusters by transcriptome mapping is a useful way to find potentially pathogenic genes among genes whose expression change is only marginal.
Molecular discrimination of responders and nonresponders to anti-TNFalpha therapy in rheumatoid arthritis by etanercept
Authors: Koczan Dirk , Drynda Susanne , Hecker Michael , Drynda Andreas , Guthke Reinhard , Kekow Joern , Thiesen Hans-Juergen
Published: May 2012

Introduction

About 30% of rheumatoid arthritis patients fail to respond adequately to TNFα-blocking therapy. There is a medical and socioeconomic need to identify molecular markers for an early prediction of responders and nonresponders.

Methods

RNA was extracted from peripheral blood mononuclear cells of 19 rheumatoid arthritis patients before the first application of the TNFα blocker etanercept as well as after 72 hours. Clinical response was assessed over 3 months using the 28-joint-count Disease Activity Score and X-ray scans. Supervised learning methods were applied to Affymetrix Human Genome U133 microarray data analysis to determine highly selective discriminatory gene pairs or triplets with prognostic relevance for the clinical outcome evinced by a decline of the 28-joint-count Disease Activity Score by 1.2.

Results

Early downregulation of expression levels secondary to TNFα neutralization was associated with good clinical responses, as shown by a decline in overall disease activity 3 months after the start of treatment. Informative gene sets include genes (for example, NFKBIA, CCL4, IL8, IL1B, TNFAIP3, PDE4B, PPP1R15A and ADM) involved in different pathways and cellular processes such as TNFα signalling via NFκB, NFκB-independent signalling via cAMP, and the regulation of cellular and oxidative stress response. Pairs and triplets within these genes were found to have a high prognostic value, reflected by prediction accuracies of over 89% for seven selected gene pairs and of 95% for 10 specific gene triplets.

Conclusion

Our data underline that early gene expression profiling is instrumental in identifying candidate biomarkers to predict therapeutic outcomes of anti-TNFα treatment regimes.
Upregulated miR-146a expression in peripheral blood mononuclear cells from rheumatoid arthritis patients
Authors: Pauley Kaleb M , Satoh Minoru , Chan Annie L , Bubb Michael R , Reeves Westley H , Chan Edward KL
Published: May 2012

Introduction

MicroRNAs are small noncoding RNA molecules that negatively regulate gene expression via degradation or translational repression of their targeted mRNAs. It is known that aberrant microRNA expression can play important roles in cancer, but the role of microRNAs in autoimmune diseases is only beginning to emerge. In this study, the expression of selected microRNAs is examined in rheumatoid arthritis.

Methods

Total RNA was isolated from peripheral blood mononuclear cells obtained from patients with rheumatoid arthritis, and healthy and disease control individuals, and the expression of miR-146a, miR-155, miR-132, miR-16, and microRNA let-7a was analyzed using quantitative real-time PCR.

Results

Rheumatoid arthritis peripheral blood mononuclear cells exhibited between 1.8-fold and 2.6-fold increases in miR-146a, miR-155, miR-132, and miR-16 expression, whereas let-7a expression was not significantly different compared with healthy control individuals. In addition, two targets of miR-146a, namely tumor necrosis factor receptor-associated factor 6 (TRAF6) and IL-1 receptor-associated kinase 1 (IRAK-1), were similarly expressed between rheumatoid arthritis patients and control individuals, despite increased expression of miR-146a in patients with rheumatoid arthritis. Repression of TRAF6 and/or IRAK-1 in THP-1 cells resulted in up to an 86% reduction in tumor necrosis factor-α production, implicating that normal miR-146a function is critical for the regulation of tumor necrosis factor-α production.

Conclusions

Recent studies have shown that synovial tissue and synovial fibroblasts from patients with rheumatoid arthritis exhibit increased expression of certain microRNAs. Our data thus demonstrate that microRNA expression in rheumatoid arthritis peripheral blood mononuclear cells mimics that of synovial tissue/fibroblasts. The increased microRNA expression in rheumatoid arthritis patients is potentially useful as a marker for disease diagnosis, progression, or treatment efficacy, but this will require confirmation using a large and well defined cohort. Our data also suggest a possible mechanism contributing to rheumatoid arthritis pathogenesis, whereby miR-146a expression is increased but unable to properly function, leading to prolonged tumor necrosis factor-α production in patients with rheumatoid arthritis.
Elevated expression of caspase-3 inhibitors, survivin and xIAP correlates with low levels of apoptosis in active rheumatoid synovium
Authors: Dharmapatni Anak ASSK , Smith Malcolm D , Findlay David M , Holding Christopher A , Evdokiou Andreas , Ahern Michael J , Weedon Helen , Chen Paul , Screaton Gavin , Xu Xiao N , Haynes David R
Published: May 2012

Introduction

Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) is a tumour necrosis factor (TNF) family member capable of inducing apoptosis in many cell types.

Methods

Using immunohistochemistry, terminal deoxynucleotidyl transferase biotin-dUTP nick end labelling (TUNEL) and real-time PCR we investigated the expression of TRAIL, TRAIL receptors and several key molecules of the intracellular apoptotic pathway in human synovial tissues from various types of arthritis and normal controls. Synovial tissues from patients with active rheumatoid arthritis (RA), inactive RA, osteoarthritis (OA) or spondyloarthritis (SpA) and normal individuals were studied.

Results

Significantly higher levels of TRAIL, TRAIL R1, TRAIL R2 and TRAIL R4 were observed in synovial tissues from patients with active RA compared with normal controls (p < 0.05). TRAIL, TRAIL R1 and TRAIL R4 were expressed by many of the cells expressing CD68 (macrophages). Lower levels of TUNEL but higher levels of cleaved caspase-3 staining were detected in tissue from active RA compared with inactive RA patients (p < 0.05). Higher levels of survivin and x-linked inhibitor of apoptosis protein (xIAP) were expressed in active RA synovial tissues compared with inactive RA observed at both the protein and mRNA levels.

Conclusions

This study indicates that the induction of apoptosis in active RA synovial tissues is inhibited despite stimulation of the intracellular pathway(s) that lead to apoptosis. This inhibition of apoptosis was observed downstream of caspase-3 and may involve the caspase-3 inhibitors, survivin and xIAP.
Physiological tonicity improves human chondrogenic marker expression through nuclear factor of activated T-cells 5 in vitro
Authors: van der Windt Anna E , Haak Esther , Das Ruud HJ , Kops Nicole , Welting Tim JM , Caron Marjolein MJ , van Til Niek P , Verhaar Jan AN , Weinans Harrie , Jahr Holger
Published: May 2012

Introduction

Chondrocytes experience a hypertonic environment compared with plasma (280 mOsm) due to the high fixed negative charge density of cartilage. Standard isolation of chondrocytes removes their hypertonic matrix, exposing them to nonphysiological conditions. During in vitro expansion, chondrocytes quickly lose their specialized phenotype, making them inappropriate for cell-based regenerative strategies. We aimed to elucidate the effects of tonicity during isolation and in vitro expansion on chondrocyte phenotype.

Methods

Human articular chondrocytes were isolated and subsequently expanded at control tonicity (280 mOsm) or at moderately elevated, physiological tonicity (380 mOsm). The effects of physiological tonicity on chondrocyte proliferation and chondrogenic marker expression were evaluated. The role of Tonicity-responsive Enhancer Binding Protein in response to physiological tonicity was investigated using nuclear factor of activated T-cells 5 (NFAT5) RNA interference.

Results

Moderately elevated, physiological tonicity (380 mOsm) did not affect chondrocyte proliferation, while higher tonicities inhibited proliferation and diminished cell viability. Physiological tonicity improved expression of chondrogenic markers and NFAT5 and its target genes, while suppressing dedifferentiation marker collagen type I and improving type II/type I expression ratios >100-fold. Effects of physiological tonicity were similar in osteoarthritic and normal (nonosteoarthritic) chondrocytes, indicating a disease-independent mechanism. NFAT5 RNA interference abolished tonicity-mediated effects and revealed that NFAT5 positively regulates collagen type II expression, while suppressing type I.

Conclusions

Physiological tonicity provides a simple, yet effective, means to improve phenotypical characteristics during cytokine-free isolation and in vitro expansion of human articular chondrocytes. Our findings will lead to the development of improved cell-based repair strategies for chondral lesions and provides important insights into mechanisms underlying osteoarthritic progression.
Resistin in idiopathic inflammatory myopathies
Authors: Filková Mária , Hulejová Hana , Kuncová Klára , Pleštilová Lenka , Cerezo Lucie Andrés , Mann Heřman , Klein Martin , Zámečník Josef , Gay Steffen , Vencovský Jiří , Šenolt Ladislav
Published: May 2012

Introduction

The purpose of this study was to evaluate and compare the serum levels and local expression of resistin in patients with idiopathic inflammatory myopathies to controls, and to determine the relationship between resistin levels, inflammation and disease activity.

Methods

Serum resistin levels were determined in 42 patients with inflammatory myopathies and 27 healthy controls. The association among resistin levels, inflammation, global disease activity and muscle strength was examined. The expression of resistin in muscle tissues from patients with inflammatory myopathies and healthy controls was evaluated. Gene expression and protein release from resistin-stimulated muscle and mononuclear cells were assessed.

Results

In patients with inflammatory myopathies, the serum levels of resistin were significantly higher than those observed in controls (8.53 ± 6.84 vs. 4.54 ± 1.08 ng/ml, P < 0.0001) and correlated with C-reactive protein (CRP) levels (r = 0.328, P = 0.044) and myositis disease activity assessment visual analogue scales (MYOACT) (r = 0.382, P = 0.026). Stronger association was observed between the levels of serum resistin and CRP levels (r = 0.717, P = 0.037) as well as MYOACT (r = 0.798, P = 0.007), and there was a trend towards correlation between serum resistin and myoglobin levels (r = 0.650, P = 0.067) in anti-Jo-1 positive patients. Furthermore, in patients with dermatomyositis, serum resistin levels significantly correlated with MYOACT (r = 0.667, P = 0.001), creatine kinase (r = 0.739, P = 0.001) and myoglobin levels (r = 0.791, P = 0.0003) and showed a trend towards correlation with CRP levels (r = 0.447, P = 0.067). Resistin expression in muscle tissue was significantly higher in patients with inflammatory myopathies compared to controls, and resistin induced the expression of interleukins (IL)-1β and IL-6 and monocyte chemoattractant protein (MCP)-1 in mononuclear cells but not in myocytes.

Conclusions

The results of this study indicate that higher levels of serum resistin are associated with inflammation, higher global disease activity index and muscle injury in patients with myositis-specific anti-Jo-1 antibody and patients with dermatomyositis. Furthermore, up-regulation of resistin in muscle tissue and resistin-induced synthesis of pro-inflammatory cytokines in mononuclear cells suggest a potential role for resistin in the pathogenesis of inflammatory myopathies.
Surface-enhanced laser desorption/ionization time-of-flight proteomic profiling of breast carcinomas identifies clinicopathologically relevant groups of patients similar to previously defined clusters from cDNA expression
Authors: Brozkova Kristyna , Budinska Eva , Bouchal Pavel , Hernychova Lenka , Knoflickova Dana , Valik Dalibor , Vyzula Rostislav , Vojtesek Borivoj , Nenutil Rudolf
Published: May 2012

Introduction

Microarray-based gene expression profiling represents a major breakthrough for understanding the molecular complexity of breast cancer. cDNA expression profiles cannot detect changes in activities that arise from post-translational modifications, however, and therefore do not provide a complete picture of all biologically important changes that occur in tumors. Additional opportunities to identify and/or validate molecular signatures of breast carcinomas are provided by proteomic approaches. Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) offers high-throughput protein profiling, leading to extraction of protein array data, calling for effective and appropriate use of bioinformatics and statistical tools.

Methods

Whole tissue lysates of 105 breast carcinomas were analyzed on IMAC 30 ProteinChip Arrays (Bio-Rad, Hercules, CA, USA) using the ProteinChip Reader Model PBS IIc (Bio-Rad) and Ciphergen ProteinChip software (Bio-Rad, Hercules, CA, USA). Cluster analysis of protein spectra was performed to identify protein patterns potentially related to established clinicopathological variables and/or tumor markers.

Results

Unsupervised hierarchical clustering of 130 peaks detected in spectra from breast cancer tissue lysates provided six clusters of peaks and five groups of patients differing significantly in tumor type, nuclear grade, presence of hormonal receptors, mucin 1 and cytokeratin 5/6 or cytokeratin 14. These tumor groups resembled closely luminal types A and B, basal and HER2-like carcinomas.

Conclusion

Our results show similar clustering of tumors to those provided by cDNA expression profiles of breast carcinomas. This fact testifies the validity of the SELDI-TOF MS proteomic approach in such a type of study. As SELDI-TOF MS provides different information from cDNA expression profiles, the results suggest the technique's potential to supplement and expand our knowledge of breast cancer, to identify novel biomarkers and to produce clinically useful classifications of breast carcinomas.
Familial relative risks for breast cancer by pathological subtype: a population-based cohort study
Authors: Mavaddat Nasim , Pharoah Paul D , Blows Fiona , Driver Kristy E , Provenzano Elena , Thompson Deborah , MacInnis Robert J , Shah Mitul ,   The SEARCH Team, Easton Douglas F , Antoniou Antonis C
Published: May 2012

Introduction

The risk of breast cancer to first degree relatives of breast cancer patients is approximately twice that of the general population. Breast cancer, however, is a heterogeneous disease and it is plausible that the familial relative risk (FRR) for breast cancer may differ by the pathological subtype of the tumour. The contribution of genetic variants associated with breast cancer susceptibility to the subtype-specific FRR is still unclear.

Methods

We computed breast cancer FRR for subtypes of breast cancer by comparing breast cancer incidence in relatives of breast cancer cases from a population-based series with known estrogen receptor (ER), progesterone receptor (PR) or human epidermal growth factor receptor 2 (HER2) status with that expected from the general population. We estimated the contribution to the FRR of genetic variants associated with breast cancer susceptibility using subtype-specific genotypic relative risks and allele frequencies for each variant.

Results

At least one marker was measured for 4,590 breast cancer cases, who reported 9,014 affected and unaffected first-degree female relatives. There was no difference between the breast cancer FRR for relatives of patients with ER-negative (FRR = 1.78, 95% confidence intervals (CI): 1.44 to 2.11) and ER-positive disease (1.82, 95% CI: 1.67 to 1.98), P = 0.99. There was some suggestion that the breast cancer FRR for relatives of patients with ER-negative disease was higher than that for ER-positive disease for ages of the relative less than 50 years old (FRR = 2.96, 95% CI: 2.04 to 3.87; and 2.05, 95% CI: 1.70 to 2.40 respectively; P = 0.07), and that the breast cancer FRR for relatives of patients with ER-positive disease was higher than for ER-negative disease when the age of the relative was greater than 50 years (FRR = 1.76, 95% CI: 1.59 to 1.93; and 1.41, 95% CI: 1.08 to 1.74 respectively, P = 0.06). We estimated that mutations in BRCA1 and BRCA2 explain 32% of breast cancer FRR for relatives of patients with ER-negative and 9.4% of the breast cancer FRR for relatives of patients with ER-positive disease. Twelve recently identified common breast cancer susceptibility variants were estimated to explain 1.9% and 9.6% of the FRR to relatives of patients with ER-negative and ER-positive disease respectively.

Conclusions

FRR for breast cancer was significantly increased for both ER-negative and ER-positive disease. Including receptor status in conjunction with genetic status may aid risk prediction in women with a family history.
Promotion of variant human mammary epithelial cell outgrowth by ionizing radiation: an agent-based model supported by in vitro studies
Authors: Mukhopadhyay Rituparna , Costes Sylvain V , Bazarov Alexey V , Hines William C , Barcellos-Hoff Mary Helen , Yaswen Paul
Published: May 2012

Introduction

Most human mammary epithelial cells (HMEC) cultured from histologically normal breast tissues enter a senescent state termed stasis after 5 to 20 population doublings. These senescent cells display increased size, contain senescence associated β-galactosidase activity, and express cyclin-dependent kinase inhibitor, p16INK4A (CDKN2A; p16). However, HMEC grown in a serum-free medium, spontaneously yield, at low frequency, variant (v) HMEC that are capable of long-term growth and are susceptible to genomic instability. We investigated whether ionizing radiation, which increases breast cancer risk in women, affects the rate of vHMEC outgrowth.

Methods

Pre-stasis HMEC cultures were exposed to 5 to 200 cGy of sparsely (X- or γ-rays) or densely (1 GeV/amu 56Fe) ionizing radiation. Proliferation (bromodeoxyuridine incorporation), senescence (senescence-associated β-galactosidase activity), and p16 expression were assayed in subcultured irradiated or unirradiated populations four to six weeks following radiation exposure, when patches of vHMEC became apparent. Long-term growth potential and p16 promoter methylation in subsequent passages were also monitored. Agent-based modeling, incorporating a simple set of rules and underlying assumptions, was used to simulate vHMEC outgrowth and evaluate mechanistic hypotheses.

Results

Cultures derived from irradiated cells contained significantly more vHMEC, lacking senescence associated β-galactosidase or p16 expression, than cultures derived from unirradiated cells. As expected, post-stasis vHMEC cultures derived from both unirradiated and irradiated cells exhibited more extensive methylation of the p16 gene than pre-stasis HMEC cultures. However, the extent of methylation of individual CpG sites in vHMEC samples did not correlate with passage number or treatment. Exposure to sparsely or densely ionizing radiation elicited similar increases in the numbers of vHMEC compared to unirradiated controls. Agent-based modeling indicated that radiation-induced premature senescence of normal HMEC most likely accelerated vHMEC outgrowth through alleviation of spatial constraints. Subsequent experiments using defined co-cultures of vHMEC and senescent cells supported this mechanism.

Conclusions

Our studies indicate that ionizing radiation can promote the outgrowth of epigenetically altered cells with pre-malignant potential.
Potential for the embryonic morphogen Nodal as a prognostic and predictive biomarker in breast cancer
Authors: Strizzi Luigi , Hardy Katharine M , Margaryan Naira V , Hillman David W , Seftor Elisabeth A , Chen Beiyun , Geiger Xochiquetzal J , Thompson E Aubrey , Lingle Wilma L , Andorfer Cathy A , Perez Edith A , Hendrix Mary JC
Published: May 2012

Introduction

The re-emergence of the tumour growth factor-beta (TGF-beta)-related embryonic morphogen Nodal has recently been reported in several different human cancers. In this study, we examined the expression of Nodal in a series of benign and malignant human breast tissues to determine the clinical significance of this expression and whether Nodal could represent a potential therapeutic target in breast cancer.

Methods

Tissue sections from 431 therapeutically naive patients diagnosed with benign or malignant breast disease were stained for Nodal by immunohistochemistry and analysed in a blinded manner. The degree of Nodal staining was subsequently correlated with available clinical data, such as diagnoses and disease stage. These tissue findings were further explored in breast cancer cell lines MDA-MB-231 and MDA-MB-468 treated with a Nodal blocking antibody to determine biological effects for target validation.

Results

A variable degree of Nodal staining was detected in all samples. The intensity of Nodal staining was significantly greater in undifferentiated, advanced stage, invasive breast cancer compared with benign breast disease or early stage breast cancer. Treatment of human breast cancer cells in vitro with Nodal blocking antibody significantly reduced proliferation and colony-forming ability in soft agar, concomitant with increased apoptosis.

Conclusions

These data suggest a potential role for Nodal as a biomarker for disease progression and a promising target for anti-Nodal therapy in breast cancer.