bluuebunny/crossref_metadata_2025 huggingface dataset:
Non-asbestos Risks of Asbestos Abatement Workers
Authors: Lange J.H. , Marangi G. , Mastrangelo G.
Published: January 2009

A survey of personal risks for asbestos abatement workers was undertaken in 2008. Information collected included age, race, smoking status, body mass index, illegal drug use, and drunk driving convictions. These results suggest that asbestos abatement workers, on average, are slightly overweight and have one the highest rates of smoking, DUI (alcohol abuse), and drug use in an identifiable occupational population. As such, these data, although small in number, support the suggestion that this occupational group consists of high-risk takers and as a result of these habits are at great risk for disease, injury, and subsequent death. Based on the information presented here, risk from asbestos exposure is minimal and in comparison to personal risks carries little concern as a practical hazard. Emphasis needs to be applied to personal habits in this population rather than asbestos exposure in that a practical approach is needed for the real risks faced by these workers.
Screening Strategies of an Indoor Air Quality Express Assessment Protocol (EAP) for Air-conditioned Offices
Authors: Mui K.W. , Wong L.T. , Hui P.S.
Published: January 2009

Poor Indoor Air Quality (IAQ) in air-conditioned offices can have adverse effects on occupants like discomfort and productivity loss. Strategic IAQ monitoring and assessment conducted with optimized resources for representative pollutants and air sampling have therefore been developed. This study evaluates the performance of a proposed simple screen process on an IAQ express assessment protocol (EAP) to identify in the office environment asymptomatic unsatisfactory IAQ. This screening process was conducted with an `IAQ index', correlated with an event of unsatisfactory IAQ through the `failure' due to other unmeasured air pollutant levels in the EAP. In this case the IAQ index is defined as the average fractional dose within certain exposure limits from the assessed top dominant contributors identified from a regional database of IAQ assessment results for workplaces. The accuracy of the proposed assessment protocol was tested with a regional IAQ database developed from IAQ measurements of common air pollutants in 422 air-conditioned offices of Hong Kong and compared with the EAP. It is reported that the application of the screening process in the EAP would improve the overall performance of the IAQ assessment without additional measurement parameters. The proposed screening protocol of the EAP would be a useful source of reference in setting up any IAQ assessment policies.
Personal Exposure to PM10 Among Bus Drivers in Sari, Iran
Authors: Mohammadyan M. , Alizadeh A. , Mohammadpour R.A.
Published: January 2009

Personal exposures to PM 10 were measured at the breathing zone in bus drivers' during 30 days of one calendar year over 6 routes in Sari city centre. The mean exposure of the drivers to PM10 was higher in autumn and winter than measured in spring and summer. Exposures to PM10 during high traffic flow in the evening were considerably higher than those measured in the morning and afternoon. The numbers of passenger on the bus, bus model and ambient temperature were found to have a significant effect on exposure to PM 10. Penetration of outdoor particulate air pollution and re-suspension of suspended fine particles in the bus were most probably the main sources of the bus drivers' personal exposure to PM10.
The role of the individual agent in Acheulean biface variability
Authors: Machin Anna
Published: January 2009

The Lower Palaeolithic, epitomized by the Acheulean biface technology, is characterized by a degree of temporal and geographical stasis that is unparalleled in the lithic record. The reasons for this phenomenon have provoked considerable debate. However, whilst it is important to understand the overall stability of this techno complex, it is also important to address the considerable degree of variability evident at the level of individual locales. Why, for instance, do bifaces show a range of shapes and degrees of refinement? Why do some show high degrees of symmetry whilst others do not? Whilst it is widely acknowledged that such variability is the result of a number of factors, to date proposed theories tend to stress one factor as being of paramount importance. These have encompassed, amongst others, the influence of raw material, subsistence function, cognitive ability and the social context of manufacture upon biface form. This article, informed by recent empirical, experimental and theoretical work, attempts to move away from these largely single-factor models to present a multi-factorial model for biface variability. This model envisages that variability is caused by the differing motivations and constraints — ecological, physiological, biological, cognitive and social — which act upon the individual agent at any given point in time.
The presence of the dead
Authors: Sørensen Tim Flohr
Published: January 2009

In academic literature, death and the dead are often treated conceptually and with little regard for the aesthetic and tactile experience of the materiality of the corpse. In this way the agency of the dead body is ignored, and the reciprocity between the deceased and the bereaved remains obscured. In effect, the corpse assumes the role of a neutral object, which blurs the particular potency of the dead body's materiality. This article proposes an alternative to this inadequacy, and discusses the changes in cemetery culture in rural Denmark within the past 50 years, addressing identity, emotions and attitudes to the materiality of the dead body. It is argued that an immaterial and subjectified recollection of the dead has, in part, replaced the previous externalized and collective commemoration due to an altered recognition of the corpse's materiality. In this way the adoption of urn burials, unmarked communal graves and lawn cemetery sections may be seen as ways of creating paradoxical yet tangible non-places, where the forging of identities and meanings of dead individuals are relieved of their material presence and proximity.
A Case Report of a Double Advancement Flap Closure Combined With an Ilizarov Technique for the Chronic Plantar Forefoot Ulceration
Authors: Belczyk Ronald , Stapleton John J. , Zgonis Thomas
Published: January 2009

Soft tissue closure of defects on the plantar surface of the foot continues to be a challenge for the reconstructive surgeon secondarily to the limited number of surgical options and often difficulty of replacing durable and similar soft tissue coverage. Primary closure and skin grafting may not be suitable for the weight-bearing surfaces of the plantar forefoot area, and closure may then be obtained by other means of plastic surgery techniques.
Review: Finding the Culprit: A Review of the Influences of Proteases on the Chronic Wound Environment
Authors: Rayment Erin A. , Upton Zee
Published: January 2009

Chronic leg ulcers are a complex medical condition with varied underlying causes and requiring diverse treatment strategies. It is generally accepted that chronic ulcers occur when the normal wound healing process is interrupted. These wounds are characterized by excessive protease activity, abundant granulation tissue, and decreased levels of growth factors, resulting in an overall poor prognosis for the patient. Many studies have focused on identifying the key proteases, specifically matrix metalloproteinases (MMPs), responsible for an ulcer's chronicity. Of note, the results of these studies are often conflicting. This report therefore focuses on a review of this literature to identify which MMPs are important in terms of ulcer prognosis and healing outcome. This has revealed that MMPs are clearly important in many biological processes in wound healing, hence are critical to consider when developing improved therapies to enhance both ulcer healing times and ulcer healing outcomes.
Endovascular Port-a-cath Insertion in a Patient With Cystic Fibrosis and Occluded Superior Vena Cava
Authors: Ali Ahmed , Zayed Hany , Wilkins Jason , Wyatt Hilary , Rashid Hisham
Published: January 2009

Introduction: Port-a-cath insertion, for long-term intravenous antibiotic therapy, is an ideal solution for patient with cystic fibrosis. However, indwelling lines are liable to many complications including catheter thrombosis especially in patients having cystic fibrosis with hypercoagulable state. Methods: An endovascular technique for insertion of a port-a-cath in a patient having cystic fibrosis with occluded superior vena cava is reported. The technique is described in detail. In addition, a review of literature for the various methods of saving a failed central venous access in these patients was performed. Results: The line was successfully inserted and remained patent without need of any further intervention for 20 months. Conclusion: In this report, several endovascular skills were used for central venous access salvage that can be used in similar situations with chronic superior vena cava occlusion, which may not be suitable for thrombolysis or stenting.
Hard Choices in School Consolidation
Authors: Warner Wanda , Lindle Jane Clark
Published: January 2009

Educational leaders face difficult decisions in ensuring that all students learn despite ongoing scarcity of resources. School communities play an important role in establishing positive learning environments and supplying the resources for student learning. Declining community conditions often present school leaders with tough choices between facilities management and instructional needs. This case illustrates how school districts maintain a focus on the best interest of students in the face of economic decline in surrounding communities. How does a district address school consolidation? How can two communities focus on their children’s futures rather than grieving over past distinctions in community identity?
Integrating copper at the nanometer length scale with Sn–3·5Ag solder to develop high performance nanocomposites
Authors: Babaghorbani P. , Nai S. M. L. , Gupta M.
Published: January 2009

In the present study, copper at the nanometer length scale is integrated with Sn–3·5Ag using the technique of powder metallurgy incorporating energy efficient microwave sintering. Superior mechanical characteristics were realised for the formulations containing nanometer length scale copper in excess of 1 vol.-%. Sn–3·5Ag reinforced with 2·5 vol.% nanosize copper particulates exhibited the best overall mechanical characteristics. Particular emphasis is placed on studying the effect of the increasing presence of nanosize copper particulates on the microstructure and property evolution of the Sn–3·5Ag matrix.
ETS2 and ERG promote megakaryopoiesis and synergize with alterations in GATA-1 to immortalize hematopoietic progenitor cells
Authors: Stankiewicz Monika J. , Crispino John D.
Published: January 2009

ETS2 and ERG are transcription factors, encoded on human chromosome 21 (Hsa21), that have been implicated in human cancer. People with Down syndrome (DS), who are trisomic for Hsa21, are predisposed to acute megakaryoblastic leukemia (AMKL). DS-AMKL blasts harbor a mutation in GATA1, which leads to loss of full-length protein but expression of the GATA-1s isoform. To assess the consequences of ETS protein misexpression on megakaryopoiesis, we expressed ETS2, ERG, and the related protein FLI-1 in wild-type and Gata1 mutant murine fetal liver progenitors. These studies revealed that ETS2, ERG, and FLI-1 facilitated the expansion of megakaryocytes from wild-type, Gata1-knockdown, and Gata1s knockin progenitors, but none of the genes could overcome the differentiation block characteristic of the Gata1-knockdown megakaryocytes. Although overexpression of ETS proteins increased the proportion of CD41+ cells generated from Gata1s-knockin progenitors, their expression led to a significant reduction in the more mature CD42 fraction. Serial replating assays revealed that overexpression of ERG or FLI-1 immortalized Gata1-knockdown and Gata1s knockin, but not wild-type, fetal liver progenitors. Immortalization was accompanied by activation of the JAK/STAT pathway, commonly seen in megakaryocytic malignancies. These findings provide evidence for synergy between alterations in GATA-1 and overexpression of ETS proteins in aberrant megakaryopoiesis.
Effects of ciclesonide and fluticasone on cortisol secretion in patients with persistent asthma
Authors: Derom E. , Louis R. , Tiesler C. , Engelstätter R. , Kaufman J-M. , Joos G. F.
Published: January 2009

We compared the systemic and clinical effects of ciclesonide (CIC) and fluticasone propionate (FP) administered, in addition to CIC 160 µg·day−1and salmeterol 50 µg twice daily, in 32 patients with persistent asthma using a randomised double-blind, placebo-controlled, double-dummy, five-period crossover design.

All patients exhibited a provocative concentration leading to a 20% decrease in forced expiratory volume in 1 s (PC20) methacholine <8 mg·mL−1and a PC20adenosine <60 mg·mL−1. Primary outcome was 24-h serum cortisol suppression after 7 days. Secondary outcomes were changes in PC20methacholine and adenosine after 9 days.

FP 500 µg·day−1and 1,000 µg·day−1significantly suppressed cortisol secretionversusplacebo by -46.2 (95% confidence interval (CI) -83.8– -8.5) nmol·L−1and by -76.1 (95% CI -112.9– -39.3) nmol·L−1, respectively. Neither dose of CIC (320 nor 640 µg·day−1) had a significant suppressive effect (-28.2 (95% CI -65.5–9.2) nmol·L−1and -37.3 (95% CI -74.7–0.0) nmol·L−1, respectively). Differences between FP 1,000 µg·day−1and both CIC treatments were statistically significant (CIC 320 µg·day−1: -48.0 (95% CI -84.8– -11.1) nmol·L−1; CIC 640 µg·day−1: -38.8 (95% CI -75.7– -1.9) nmol·L−1). Compared with placebo, the increase in PC20adenosine after the four treatments was small, but significant. Greater improvements in PC20adenosine were seen with FP 500 µg·day−1(1.8 (95% CI 1.0–2.6) doubling concentrations) compared with CIC 320 μg·day−1(0.9 (95% CI 0.1–1.7) doubling concentrations). No significant difference was seen between CIC 640 μg·day−1and FP 1,000 μg·day−1.

For a similar decrease in hyperresponsiveness, cortisol secretion was suppressed significantly with moderate-to-high doses of fluticasone propionate, but not with ciclesonide.
Evaluation of allergic lung inflammation by computed tomography in a rat modelin vivo
Authors: Jobse B. N. , Johnson J. R. , Farncombe T. H. , Labiris R. , Walker T. D. , Goncharova S. , Jordana M.
Published: January 2009

The ability of micro-computed tomography (CT) to noninvasively evaluate allergic pulmonary inflammation in an experimental model was investigated. In addition, two image segmentation methods and the value of respiratory gating were investigated in the context of this model.

Brown Norway rats were exposed to one of four doses of house dust mite (HDM) extract (0, 0.15, 15 or 150 μg) delivered intratracheally every 24 h for 10 days. CT scanning was performed at baseline and after several longitudinal HDM exposures.

Both thoracic- and lung-segmentation methods yielded similar results when standardisation practices were employed. While tissue histology correlated well with CT images, cell counts from bronchoalveolar lavage depicted greater inflammation than did density measures from CT images. Evidence from representative CT slices and transaxial density distribution indicated that inflammation was primarily associated with major airways and extended into the periphery from these focal points. Respiratory gating demonstrated that images of the inspiratory state provided greater contrast of inflammatory processes. Lastly, decreases in tidal volumes indicated significant mechanical respiratory changes in animals exposed to both 15 and 150 μg.

In summary, CT image segmentation can extract pertinent data onin vivoallergic airway/lung inflammation. Furthermore, respiratory gating provides additional contrast and insight into these quantification practices.
Effect of heliox breathing on flow limitation in chronic heart failure patients
Authors: Pecchiari M. , Anagnostakos T. , D'Angelo E. , Roussos C. , Nanas S. , Koutsoukou A.
Published: January 2009

Patients with chronic heart failure (CHF) exhibit orthopnoea and tidal expiratory flow limitation in the supine position. It is not known whether the flow-limiting segment occurs in the peripheral or central part of the tracheobronchial tree. The location of the flow-limiting segment can be inferred from the effects of heliox (80% helium/20% oxygen) administration. If maximal expiratory flow increases with this low-density mixture, the choke point should be located in the central airways, where the wave-speed mechanism dominates. If the choke point were located in the peripheral airways, where maximal flow is limited by a viscous mechanism, heliox should have no effect on flow limitation and dynamic hyperinflation.

Tidal expiratory flow limitation, dynamic hyperinflation and breathing pattern were assessed in 14 stable CHF patients during air and heliox breathing at rest in the sitting and supine position.

No patient was flow-limited in the sitting position. In the supine posture, eight patients exhibited tidal expiratory flow limitation on air. Heliox had no effect on flow limitation and dynamic hyperinflation and only minor effects on the breathing pattern.

The lack of density dependence of maximal expiratory flow implies that, in CHF patients, the choke point is located in the peripheral airways.
FcϵRI-mediated thymic stromal lymphopoietin production by interleukin-4-primed human mast cells
Authors: Okayama Y. , Okumura S. , Sagara H. , Yuki K. , Sasaki T. , Watanabe N. , Fueki M. , Sugiyama K. , Takeda K. , Fukuda T. , Saito H. , Ra C.
Published: January 2009

A significant increase of mRNA expression of thymic stromal lymphopoietin (TSLP) has been reported in the bronchial mast cells (MCs) of asthmatic subjects; however, the mechanism underlying the upregulation of TSLP mRNA and protein remains unknown.

FcϵRI-mediated activation of human MCs upregulated TSLP mRNA expression by 5.2±2.9-fold, while activation of the MCs using lipopolysaccharide and polyriboinosinic:polyribocytidylic acid failed to upregulate TSLP. Stimulation of MCs with interleukin (IL)-4 alone did not affect the TSLP mRNA expression, while pre-incubation of MCs with IL-4 for 48 h significantly enhanced the FcϵRI-mediated TSLP mRNA expression (by 53.7±15.9-fold; p<0.05) and the amount of TSLP in the cell pellets increased significantly from 23.4±4.3 pg·mL−1to 121.5±3.7 pg·mL−1(p<0.0001). However, the released TSLP was rapidly degraded by proteases that were released by MCs. We identified the population of cells expressing TSLP in the lungs of 16 asthmatic and 11 control subjects by immunohistochemistry. The percentage of TSLP-positive MCs in the total population of MCs was significantly increased in asthmatic airways (p<0.0001).

Thus, MCs are able to store TSLP intracellularly and to produce TSLP following aggregation of FcϵRI in the presence of IL-4.
Serum surfactant protein D is steroid sensitive and associated with exacerbations of COPD
Authors: Lomas D. A. , Silverman E. K. , Edwards L. D. , Locantore N. W. , Miller B. E. , Horstman D. H. , Tal-Singer R.
Published: January 2009

Surfactant protein (SP)-D is a lung-derived protein that has been proposed as a biomarker for inflammatory lung disease.

Serum SP-D was evaluated as a biomarker for components of chronic obstructive pulmonary disease (COPD) in the Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE) cohort and its response assessed to the administration of the anti-inflammatory agent prednisolone.

The median level of serum SP-D was significantly elevated in 1,888 individuals with COPD compared to 296 current and former smokers without airflow obstruction (121.1 and 114.3 ng·mL−1, respectively; p = 0.021) and 201 nonsmokers (82.2 ng·ml−1; p<0.001). There was no correlation with the severity of COPD. Individuals with COPD who had a serum SP-D concentration that was greater than the 95th percentile of nonsmokers (175.4 ng·mL−1) showed an increased risk of exacerbations over the following 12 months (adjusted OR 1.30; 95% CI 1.03–1.63). Treatment with 20 mg·day−1prednisolone for 4 weeks resulted in a fall in serum SP-D levels (126.0 to 82.1 ng·mL−1; p<0.001) but no significant change in post-bronchodilator forced expiratory volume in 1 s.

Serum SP-D concentration is raised in smokers and may be useful in identifying individuals who are at increased risk of exacerbations of COPD. It may represent an intermediate measure for the development of novel anti-inflammatory agents.
ArrayIDer: automated structural re-annotation pipeline for DNA microarrays
Authors: van den Berg Bart HJ , Konieczka Jay H , McCarthy Fiona M , Burgess Shane C
Published: January 2009

Background

Systems biology modeling from microarray data requires the most contemporary structural and functional array annotation. However, microarray annotations, especially for non-commercial, non-traditional biomedical model organisms, are often dated. In addition, most microarray analysis tools do not readily accept EST clone names, which are abundantly represented on arrays. Manual re-annotation of microarrays is impracticable and so we developed a computational re-annotation tool (ArrayIDer) to retrieve the most recent accession mapping files from public databases based on EST clone names or accessions and rapidly generate database accessions for entire microarrays.

Results

We utilized the Fred Hutchinson Cancer Research Centre 13K chicken cDNA array – a widely-used non-commercial chicken microarray – to demonstrate the principle that ArrayIDer could markedly improve annotation. We structurally re-annotated 55% of the entire array. Moreover, we decreased non-chicken functional annotations by 2 fold. One beneficial consequence of our re-annotation was to identify 290 pseudogenes, of which 66 were previously incorrectly annotated.

Conclusion

ArrayIDer allows rapid automated structural re-annotation of entire arrays and provides multiple accession types for use in subsequent functional analysis. This information is especially valuable for systems biology modeling in the non-traditional biomedical model organisms.
Transcriptomic comparison of Aspergillus niger growing on two different sugars reveals coordinated regulation of the secretory pathway
Authors: Jørgensen Thomas R , Goosen Theo , van den Hondel Cees AMJJ , Ram Arthur FJ , Iversen Jens JL
Published: January 2009

Background

The filamentous fungus,Aspergillus niger, responds to nutrient availability by modulating secretion of various substrate degrading hydrolases. This ability has made it an important organism in industrial production of secreted glycoproteins. The recent publication of theA. nigergenome sequence and availability of microarrays allow high resolution studies of transcriptional regulation of basal cellular processes, like those of glycoprotein synthesis and secretion. It is known that the activities of certain secretory pathway enzymes involvedN-glycosylation are elevated in response to carbon source induced secretion of the glycoprotein glucoamylase. We have investigated whether carbon source dependent enhancement of protein secretion can lead to upregulation of secretory pathway elements extending beyond those involved inN-glycosylation.

Results

This study compares the physiology and transcriptome ofA. nigergrowing at the same specific growth rate (0.16 h-1) on xylose or maltose in carbon-limited chemostat cultures. Transcription profiles were obtained using Affymetrix GeneChip analysis of six replicate cultures for each of the two growth-limiting carbon sources. The production rate of extracellular proteins per gram dry mycelium was about three times higher on maltose compared to xylose. The defined culture conditions resulted in high reproducibility, discriminating even low-fold differences in transcription, which is characteristic of genes encoding basal cellular functions. This included elements in the secretory pathway and central metabolic pathways. Increased protein secretion on maltose was accompanied by induced transcription of > 90 genes related to protein secretion. The upregulated genes encode key elements in protein translocation to the endoplasmic reticulum (ER), folding,N-glycosylation, quality control, and vesicle packaging and transport between ER and Golgi. The induction effect of maltose resembles the unfolded protein response (UPR), which results from ER-stress and has previously been defined by treatment with chemicals interfering with folding of glycoproteins or by expression of heterologous proteins.

Conclusion

We show that upregulation of secretory pathway genes also occurs in conditions inducing secretion of endogenous glycoproteins – representing a more normal physiological state. Transcriptional regulation of protein synthesis and secretory pathway genes may thus reflect a general mechanism for modulation of secretion capacity in response to the conditional need for extracellular enzymes.
Brain-derived neurotrophic factor modulation of Kv1.3 channel is disregulated by adaptor proteins Grb10 and nShc
Authors: Colley Beverly S , Cavallin Melissa A , Biju KC , Marks David R , Fadool Debra A
Published: January 2009

Background

Neurotrophins are important regulators of growth and regeneration, and acutely, they can modulate the activity of voltage-gated ion channels. Previously we have shown that acute brain-derived neurotrophic factor (BDNF) activation of neurotrophin receptor tyrosine kinase B (TrkB) suppresses the Shaker voltage-gated potassium channel (Kv1.3) via phosphorylation of multiple tyrosine residues in the N and C terminal aspects of the channel protein. It is not known how adaptor proteins, which lack catalytic activity, but interact with members of the neurotrophic signaling pathway, might scaffold with ion channels or modulate channel activity.

Results

We report the co-localization of two adaptor proteins, neuronal Src homology and collagen (nShc) and growth factor receptor-binding protein 10 (Grb10), with Kv1.3 channel as demonstrated through immunocytochemical approaches in the olfactory bulb (OB) neural lamina. To further explore the specificity and functional ramification of adaptor/channel co-localization, we performed immunoprecipitation and Western analysis of channel, kinase, and adaptor transfected human embryonic kidney 293 cells (HEK 293). nShc formed a direct protein-protein interaction with Kv1.3 that was independent of BDNF-induced phosphorylation of Kv1.3, whereas Grb10 did not complex with Kv1.3 in HEK 293 cells. Both adaptors, however, co-immunoprecipitated with Kv1.3 in native OB. Grb10 was interestingly able to decrease the total expression of Kv1.3, particularly at the membrane surface, and subsequently eliminated the BDNF-induced phosphorylation of Kv1.3. To examine the possibility that the Src homology 2 (SH2) domains of Grb10 were directly binding to basally phosphorylated tyrosines in Kv1.3, we utilized point mutations to substitute multiple tyrosine residues with phenylalanine. Removal of the tyrosines 111–113 and 449 prevented Grb10 from decreasing Kv1.3 expression. In the absence of either adaptor protein, channel co-expression reciprocally down-regulated expression and tyrosine phosphorylation of TrkB kinase and related insulin receptor kinase. Finally, through patch-clamp electrophysiology, we found that the BDNF-induced current suppression of the channel was prevented by both nShc and Grb10.

Conclusion

We report that adaptor protein alteration of kinase-induced Kv1.3 channel modulation is related to the degree of direct protein-protein association and that the channel itself can reciprocally modulate receptor-linked tyrosine kinase expression and activity.
The critical role of ERK in death resistance and invasiveness of hypoxia-selected glioblastoma cells
Authors: Kim Jee-Youn , Kim Yong-Jun , Lee Sun , Park Jae-Hoon
Published: January 2009

Background

The rapid growth of tumor parenchyma leads to chronic hypoxia that can result in the selection of cancer cells with a more aggressive behavior and death-resistant potential to survive and proliferate. Thus, identifying the key molecules and molecular mechanisms responsible for the phenotypic changes associated with chronic hypoxia has valuable implications for the development of a therapeutic modality. The aim of this study was to identify the molecular basis of the phenotypic changes triggered by chronic repeated hypoxia.

Methods

Hypoxia-resistant T98G (HRT98G) cells were selected by repeated exposure to hypoxia and reoxygenation. Cell death rate was determined by the trypan blue exclusion method and protein expression levels were examined by western blot analysis. The invasive phenotype of the tumor cells was determined by the Matrigel invasion assay. Immunohistochemistry was performed to analyze the expression of proteins in the brain tumor samples. The Student T-test and Pearson Chi-Square test was used for statistical analyses.

Results

We demonstrate that chronic repeated hypoxic exposures cause T98G cells to survive low oxygen tension. As compared with parent cells, hypoxia-selected T98G cells not only express higher levels of anti-apoptotic proteins such as Bcl-2, Bcl-XL, and phosphorylated ERK, but they also have a more invasive potential in Matrigel invasion chambers. Activation or suppression of ERK pathways with a specific activator or inhibitor, respectively, indicates that ERK is a key molecule responsible for death resistance under hypoxic conditions and a more invasive phenotype. Finally, we show that the activation of ERK is more prominent in malignant glioblastomas exposed to hypoxia than in low grade astrocytic glial tumors.

Conclusion

Our study suggests that activation of ERK plays a pivotal role in death resistance under chronic hypoxia and phenotypic changes related to the invasive phenotype of HRT98G cells compared to parent cells.
Development of real time PCR for detection and quantitation of Dengue Viruses
Authors: Gurukumar KR , Priyadarshini D , Patil JA , Bhagat A , Singh A , Shah PS , Cecilia D
Published: January 2009

Background

Dengue virus (DENV), a mosquito borne flavivirus is an important pathogen causing more than 50 million infections every year around the world. Dengue diagnosis depends on serology, which is not useful in the early phase of the disease and virus isolation, which is laborious and time consuming. There is need for a rapid, sensitive and high throughput method for detection of DENV in the early stages of the disease. Several real-time PCR assays have been described for dengue viruses, but there is scope for improvement. The new generation TaqMan Minor Groove Binding (MGB) probe approach was used to develop an improved real time RT-PCR (qRT-PCR) for DENV in this study.

Results

The 3'UTR of thirteen Indian strains of DENV was sequenced and aligned with 41 representative sequences from GenBank. A region conserved in all four serotypes was used to target primers and probes for the qRT-PCR. A single MGB probe and a single primer pair for all the four serotypes of DENV were designed. The sensitivity of the two step qRT-PCR assay was10 copies of RNA molecules per reaction. The specificity and sensitivity of the assay was 100% when tested with a panel of 39 known positive and negative samples. Viral RNA could be detected and quantitated in infected mouse brain, cell cultures, mosquitoes and clinical samples. Viral RNA could be detected in patients even after seroconversion till 10 days post onset of infection. There was no signal with Japanese Encephalitis (JE), West Nile (WN), Chikungunya (CHK) viruses or with Leptospira, Plasmodium vivax, Plasmodium falciparum and Rickettsia positive clinical samples.

Conclusion

We have developed a highly sensitive and specific qRT-PCR for detection and quantitation of dengue viruses. The assay will be a useful tool for differential diagnosis of dengue fever in a situation where a number of other clinically indistinguishable infectious diseases like malaria, Chikungunya, rickettsia and leptospira occur. The ability of the assay to detect DENV-2 in inoculated mosquitoes makes it a potential tool for detecting DENV in field-caught mosquitoes.
The Orexigenic Activity of the Hypothalamic Neuropeptide 26RFa Is Mediated by the Neuropeptide Y and Proopiomelanocortin Neurons of the Arcuate Nucleus
Authors: Lectez Benoît , Jeandel Lydie , El-Yamani Fatima-Zohra , Arthaud Sébastien , Alexandre David , Mardargent Aurélie , Jégou Sylvie , Mounien Lourdes , Bizet Patrice , Magoul Rabia , Anouar Youssef , Chartrel Nicolas
Published: January 2009

26RFa is a hypothalamic RFamide neuropeptide that was identified as the endogenous ligand of the orphan G protein-coupled receptor, GPR103, and that stimulates appetite in mice. Up until now, the mechanism of action of 26RFa in the hypothalamic control of food intake remains unknown. The high density of GPR103 in the arcuate nucleus (Arc) prompted us to investigate, in the present study, the effects of 26RFa on the rat neuropeptide Y (NPY)/proopiomelanocortin (POMC) system. Intracerebroventricular injection of 26RFa stimulated NPY expression and release in the basal hypothalamus, whereas it decreased POMC expression and α-MSH release, and these effects were associated with an increase in food intake. A double in situ hybridization procedure indicated that the 26RFa receptor is present in NPY neurons of the Arc, but not in POMC neurons. Central administration of NPY Y1 and Y5 receptor antagonists abolished the inhibitory effects of 26RFa on POMC expression and α-MSH release, and reversed 26RFa-induced food consumption. Finally, 26RFa antagonized the effects of leptin on NPY expression and release, POMC expression and α-MSH release, and food intake. Altogether, the present data demonstrate for the first time that 26RFa exerts its orexigenic activity by stimulating the release of NPY in the Arc, which in turn inhibits POMC neurons by activating the Y1 and Y5 receptors. It is also suggested that the balance 26RFa/leptin is an important parameter in the maintenance of energy homeostasis.
Molecular Evolution of Multiple Forms of Kisspeptins and GPR54 Receptors in Vertebrates
Authors: Lee Yeo Reum , Tsunekawa Kenta , Moon Mi Jin , Um Haet Nim , Hwang Jong-Ik , Osugi Tomohiro , Otaki Naohito , Sunakawa Yuya , Kim Kyungjin , Vaudry Hubert , Kwon Hyuk Bang , Seong Jae Young , Tsutsui Kazuyoshi
Published: January 2009

Kisspeptin and its receptor GPR54 play important roles in mammalian reproduction and cancer metastasis. Because the KiSS and GPR54 genes have been identified in a limited number of vertebrate species, mainly in mammals, the evolutionary history of these genes is poorly understood. In the present study, we have cloned multiple forms of kisspeptin and GPR54 cDNAs from a variety of vertebrate species. We found that fish have two forms of kisspeptin genes, KiSS-1 and KiSS-2, whereas Xenopus possesses three forms of kisspeptin genes, KiSS-1a, KiSS-1b, and KiSS-2. The nonmammalian KiSS-1 gene was found to be the ortholog of the mammalian KiSS-1 gene, whereas the KiSS-2 gene is a novel form, encoding a C-terminally amidated dodecapeptide in the Xenopus brain. This study is the first to identify a mature form of KiSS-2 product in the brain of any vertebrate. Likewise, fish possess two receptors, GPR54-1 and GPR54-2, whereas Xenopus carry three receptors, GPR54-1a, GPR54-1b, and GPR54-2. Sequence identity and genome synteny analyses indicate that Xenopus GPR54-1a is a human GPR54 ortholog, whereas Xenopus GPR54-1b is a fish GPR54-1 ortholog. Both kisspeptins and GPR54s were abundantly expressed in the Xenopus brain, notably in the hypothalamus, suggesting that these ligand-receptor pairs have neuroendocrine and neuromodulatory roles. Synthetic KiSS-1 and KiSS-2 peptides activated GPR54s expressed in CV-1 cells with different potencies, indicating differential ligand selectivity. These data shed new light on the molecular evolution of the kisspeptin-GPR54 system in vertebrates.
Early mouse caudal development relies on crosstalk between retinoic acid,Shh and Fgf signalling pathways
Authors: Ribes Vanessa , Le Roux Isabelle , Rhinn Muriel , Schuhbaur Brigitte , Dollé Pascal
Published: January 2009

The progressive generation of embryonic trunk structures relies on the proper patterning of the caudal epiblast, which involves the integration of several signalling pathways. We have investigated the function of retinoic acid (RA) signalling during this process. We show that, in addition to posterior mesendoderm, primitive streak and node cells transiently express the RA-synthesizing enzyme Raldh2 prior to the headfold stage. RA-responsive cells (detected by the RA-activated RARE-lacZtransgene) are additionally found in the epiblast layer. Analysis of RA-deficient Raldh2-/- mutants reveals early caudal patterning defects, with an expansion of primitive streak and mesodermal markers at the expense of markers of the prospective neuroepithelium. As a result, many genes involved in neurogenesis and/or patterning of the embryonic spinal cord are affected in their expression. We demonstrate that RA signalling is required at late gastrulation stages for mesodermal and neural progenitors to respond to the Shh signal. Whole-embryo culture experiments indicate that the proper response of cells to Shh requires two RA-dependent mechanisms: (1) a balanced antagonism between Fgf and RA signals, and (2) a RA-mediated repression of Gli2 expression. Thus, an interplay between RA, Fgf and Shh signalling is likely to be an important mechanism underpinning the tight regulation of caudal embryonic development.
Actomyosin stiffens the vertebrate embryo during crucial stages of elongation and neural tube closure
Authors: Zhou Jian , Kim Hye Young , Davidson Lance A.
Published: January 2009

Physical forces drive the movement of tissues within the early embryo. Classical and modern approaches have been used to infer and, in rare cases,measure mechanical properties and the location and magnitude of forces within embryos. Elongation of the dorsal axis is a crucial event in early vertebrate development, yet the mechanics of dorsal tissues in driving embryonic elongation that later support neural tube closure and formation of the central nervous system is not known. Among vertebrates, amphibian embryos allow complex physical manipulation of embryonic tissues that are required to measure the mechanical properties of tissues. In this paper, we measure the stiffness of dorsal isolate explants of frog (Xenopus laevis) from gastrulation to neurulation and find dorsal tissues stiffen from less than 20 Pascal (Pa) to over 80 Pa. By iteratively removing tissues from these explants, we find paraxial somitic mesoderm is nearly twice as stiff as either the notochord or neural plate, and at least 10-fold stiffer than the endoderm. Stiffness measurements from explants with reduced fibronectin fibril assembly or disrupted actomyosin contractility suggest that it is the state of the actomyosin cell cortex rather than accumulating fibronectin that controls tissue stiffness in early amphibian embryos.
Notch mediates Wnt and BMP signals in the early separation of smooth muscle progenitors and blood/endothelial common progenitors
Authors: Shin Masahiro , Nagai Hiroki , Sheng Guojun
Published: January 2009

During embryonic development in amniotes, the extraembryonic mesoderm,where the earliest hematopoiesis and vasculogenesis take place, also generates smooth muscle cells (SMCs). It is not well understood how the differentiation of SMCs is linked to that of blood (BCs) and endothelial (ECs) cells. Here we show that, in the chick embryo, the SMC lineage is marked by the expression of a bHLH transcription factor, dHand. Notch activity in nascent ventral mesoderm cells promotes SMC progenitor formation and mediates the separation of SMC and BC/EC common progenitors marked by another bHLH factor, Scl. This is achieved by crosstalk with the BMP and Wnt pathways,which are involved in mesoderm ventralization and SMC lineage induction,respectively. Our findings reveal a novel role of the Notch pathway in early ventral mesoderm differentiation, and suggest a stepwise separation among its three main lineages, first between SMC progenitors and BC/EC common progenitors, and then between BCs and ECs.
The polarly localized D6 PROTEIN KINASE is required for efficient auxin transport inArabidopsis thaliana
Authors: Zourelidou Melina , Müller Isabel , Willige Björn C. , Nill Carola , Jikumaru Yusuke , Li Hanbing , Schwechheimer Claus
Published: January 2009

The phytohormone auxin is a major determinant of plant growth and differentiation. Directional auxin transport and auxin responses are required for proper embryogenesis, organ formation, vascular development, and tropisms. Members of several protein families, including the PIN auxin efflux facilitators, have been implicated in auxin transport; however, the regulation of auxin transport by signaling proteins remains largely unexplored. We have studied a family of four highly homologous AGC protein kinases, which we designated the D6 protein kinases (D6PKs). We found that d6pk mutants have defects in lateral root initiation, root gravitropism, and shoot differentiation in axillary shoots, and that these phenotypes correlate with a reduction in auxin transport. Interestingly, D6PK localizes to the basal(lower) membrane of Arabidopsis root cells, where it colocalizes with PIN1, PIN2 and PIN4. D6PK and PIN1 interact genetically, and D6PK phosphorylates PIN proteins in vitro and in vivo. Taken together, our data show that D6PK is required for efficient auxin transport and suggest that PIN proteins are D6PK phosphorylation targets.
Rostral and caudal pharyngeal arches share a common neural crest ground pattern
Authors: Minoux Maryline , Antonarakis Gregory S. , Kmita Marie , Duboule Denis , Rijli Filippo M.
Published: January 2009

In vertebrates, face and throat structures, such as jaw, hyoid and thyroid cartilages develop from a rostrocaudal metameric series of pharyngeal arches,colonized by cranial neural crest cells (NCCs). Colinear Hox gene expression patterns underlie arch specific morphologies, with the exception of the first(mandibular) arch, which is devoid of any Hox gene activity. We have previously shown that the first and second (hyoid) arches share a common,Hox-free, patterning program. However, whether or not more posterior pharyngeal arch neural crest derivatives are also patterned on the top of the same ground-state remained an unanswered question. Here, we show that the simultaneous inactivation of all Hoxa cluster genes in NCCs leads to multiple jaw and first arch-like structures, partially replacing second, third and fourth arch derivatives, suggesting that rostral and caudal arches share the same mandibular arch-like ground patterning program. The additional inactivation of the Hoxd cluster did not significantly enhance such a homeotic phenotype, thus indicating a preponderant role of Hoxa genes in patterning skeletogenic NCCs. Moreover, we found that Hoxa2 and Hoxa3act synergistically to pattern third and fourth arch derivatives. These results provide insights into how facial and throat structures are assembled during development, and have implications for the evolution of the pharyngeal region of the vertebrate head.
Definitive hematopoietic stem/progenitor cells manifest distinct differentiation output in the zebrafish VDA and PBI
Authors: Jin Hao , Sood Raman , Xu Jin , Zhen Fenghua , English Milton A. , Liu P. Paul , Wen Zilong
Published: January 2009

One unique feature of vertebrate definitive hematopoiesis is the ontogenic switching of hematopoietic stem cells from one anatomical compartment or niche to another. In mice, hematopoietic stem cells are believed to originate in the aorta-gonad-mesonephros (AGM), subsequently migrate to the fetal liver (FL)and finally colonize the bone marrow (BM). Yet, the differentiation potential of hematopoietic stem cells within early niches such as the AGM and FL remains incompletely defined. Here, we present in vivo analysis to delineate the differentiation potential of definitive hematopoietic stem/progenitor cells(HSPCs) in the zebrafish AGM and FL analogies, namely the ventral wall of dorsal aorta (VDA) and the posterior blood island (PBI), respectively. Cell fate mapping and analysis of zebrafish runx1w84x and vlad tepes (vltm651) mutants revealed that HSPCs in the PBI gave rise to both erythroid and myeloid lineages. However, we surprisingly found that HSPCs in the VDA were not quiescent but were uniquely adapted to generate myeloid but not erythroid lineage cells. We further showed that such distinct differentiation output of HSPCs was, at least in part,ascribed to the different micro-environments present in these two niches. Our results highlight the importance of niche in shaping the differentiation output of developing HSPCs.
Formation of thebicoidmorphogen gradient: an mRNA gradient dictates the protein gradient
Authors: Spirov Alexander , Fahmy Khalid , Schneider Martina , Frei Erich , Noll Markus , Baumgartner Stefan
Published: January 2009

The Bicoid (Bcd) protein gradient is generally believed to be established in pre-blastoderm Drosophila embryos by the diffusion of Bcd protein after translation of maternal mRNA, which serves as a strictly localized source of Bcd at the anterior pole. However, we previously published evidence that the Bcd gradient is preceded by a bcd mRNA gradient. Here, we have revisited and extended this observation by showing that the bcdmRNA and Bcd protein gradient profiles are virtually identical at all times. This confirms our previous conclusion that the Bcd gradient is produced by a bcd mRNA gradient rather than by diffusion. Based on our observation that bcd mRNA colocalizes with Staufen (Stau), we propose that the bcd mRNA gradient forms by a novel mechanism involving quasi-random active transport of a Stau-bcd mRNA complex through a nonpolar microtubular network, which confines the bcd mRNA to the cortex of the embryo.
The influence of the Hosford exponent on the critical major strain of a sheet metal
Authors: Guven U
Published: January 2009

In the present investigation, the critical major strain in anisotropic sheet metal forming is calculated under three axial stress states. Plastic analysis is based on the modified Hosford yield criterion, the Levy—Mises stress—strain increment relationship, and the power law material constitutive equation. Results show that the critical major strain is usually insensitive to the Hosford exponent.
Hermansky-Pudlak syndrome in the peripartum period
Authors: Tong Iris L , Bourjeily Ghada
Published: January 2009

Hermansky-Pudlak syndrome (HPS) is a disease characterized by the triad of oculocutaneous albinism, bleeding diathesis and organ failure secondary to lysosomal accumulation of ceroid lipofuscin. We report the case of a pregnant woman with HPS who had a successful vaginal delivery with the administration of desmopressin.
Type 2 diabetes in pregnancy: importance of optimized care before, during and after pregnancy
Authors: Keely E
Published: January 2009

Women with Type 2 diabetes (T2DM) are an increasingly important part of the practice of obstetric medicine. The rising rates of obesity and advanced maternal age have resulted in a surge in the number of pregnant women with T2DM. The hyperglycaemia and associated conditions of the metabolic syndrome lead to poor obstetric outcome and impact on the long-term health of the mother and offspring. It is essential that women and care-givers recognize the seriousness of T2DM in pregnancy and strive to improve prepregnancy care, obstetric outcome and the long-term health of both the mother and child.