bluuebunny/crossref_metadata_2025 huggingface dataset:
Dysfunctional telomeres in primary cells from Fanconi anemia FANCD2 patients
Authors: Joksic Ivana , Vujic Dragana , Guc-Scekic Marija , Leskovac Andreja , Petrovic Sandra , Ojani Maryam , Trujillo Juan P , Surralles Jordi , Zivkovic Maja , Stankovic Aleksandra , Slijepcevic Predrag , Joksic Gordana
Published: September 2012

Background

Fanconi anemia (FA) is characterized by sensitivity to DNA cross-linking agents, mild cellular, and marked clinical radio sensitivity. In this study we investigated telomeric abnormalities of non-immortalized primary cells (lymphocytes and fibroblasts) derived from FA patients of the FA-D2 complementation group, which provides a more accurate physiological assessment than is possible with transformed cells or animal models.

Results

We analyzed telomere length, telomere dysfunction-induced foci (TIFs), sister chromatid exchanges (SCE), telomere sister chromatid exchanges (T-SCE), apoptosis and expression of shelterin components TRF1 and TRF2. FANCD2 lymphocytes exhibited multiple types of telomeric abnormalities, including premature telomere shortening, increase in telomeric recombination and aberrant telomeric structures ranging from fragile to long-string extended telomeres. The baseline incidence of SCE in FANCD2 lymphocytes was reduced when compared to control, but in response to diepoxybutane (DEB) the 2-fold higher rate of SCE was observed. In contrast, control lymphocytes showed decreased SCE incidence in response to DEB treatment. FANCD2 fibroblasts revealed a high percentage of TIFs, decreased expression of TRF1 and invariable expression of TRF2. The percentage of TIFs inversely correlated with telomere length, emphasizing that telomere shortening is the major reason for the loss of telomere capping function. Upon irradiation, a significant decrease of TIFs was observed at all recovery times. Surprisingly, a considerable percentage of TIF positive cells disappeared at the same time when incidence of γ-H2AX foci was maximal. Both FANCD2 leucocytes and fibroblasts appeared to die spontaneously at higher rate than control. This trend was more evident upon irradiation; the percentage of leucocytes underwent apoptosis was 2.59- fold higher than that in control, while fibroblasts exhibited a 2- h delay before entering apoptosis.

Conclusion

The results of our study showed that primary cells originating from FA-D2 patients display shorten telomeres, elevated incidence of T-SCEs and high frequency of TIFs. Disappearance of TIFs in early response to irradiation represent distinctive feature of FANCD2 cells that should be examined further.
Effect of adiponectin gene polymorphisms on waist circumference in patients with diabetes
Authors: Hasani-Ranjbar Shirin , Amoli Mahsa M , Tabatabaei-Malazy Ozra , Rumi Yalda , Tavakkoly-Bazzaz Javad , Samimi Hilda , Abbasifarid Elnaz
Published: September 2012

Background

Plasma levels of adiponectin which is secreted from adipose tissue are associated with various parameters of metabolic syndrome. This effect seems to be a result of interactions between genetic and environmental factors including central obesity. The present study was carried out to investigate the possibility of relation between single nucleotide polymorphisms of adiponectin gene (+45 T/G and −11391 G/A) and waist circumferences (WC) in patients with type 2 diabetes.

Methods

This cross-sectional study was conducted on n = 238 diabetic patients selected as cases and n = 159 as healthy control who were recruited from Rafsanjan city in south – east of Iran. The possible association of +45 T/G and –11391 G/A adiponectin gene polymorphisms with WC according to age and sex was evaluated.

Results

There was no significant difference in distribution of frequencies of +45 T/G and –11391 G/A adiponectin gene polymorphisms in each group. We only found a significant association between –11391 G/A adiponectin gene polymorphism with WC in diabetic group (p = 0.021). This association was remained significant after adjustment in multivariate regression model (p = 0.019, OR: 0.244, 95%CI: 0.075-0.791) and also this effect was independent of sex and age.

Conclusion

We found higher abdominal obesity in GA or AA carriers of adiponectin – 11391 G/A genotype in type 2 diabetes patients independent of age and sex.
Damage Assessment of the 2010 Chile Earthquake and Tsunami Using Terrestrial Laser Scanning
Authors: Olsen Michael J. , Cheung Kwok Fai , YamazakI Yoshiki , Butcher Shawn , Garlock Maria , Yim Solomon , McGarity Sara , Robertson Ian , Burgos Luis , Young Yin Lu
Published: September 2012

In the wake of the 2010 Chile earthquake and tsunami, a reconnaissance survey recorded earthquake and tsunami damage using terrestrial laser scanning (TLS), which is capable of detecting details that most traditional reconnaissance methods cannot. TLS enables precise measurements of structural deformations and damage (including shear cracking of concrete walls, concrete spalling, and damage of rebars), as well as soil deformations and damage (including erosion, scour, liquefaction, lateral spread, slope failure, and ground displacement). Advanced measurements such as minute structural rotations, spatial distribution of cracks, volumetric and positional change calculations can also be obtained. Herein, we present various types of detailed measurements and analyses using TLS data obtained at several sites that were damaged by the earthquake and/or tsunami in Concepción, Constitución, Dichato, and Talcahuano. Moreover, this high-resolution data has enabled a unique avenue for virtual, post-visit analysis, providing additional insights that were not readily observable during the field visit.
Performance of Port Facilities in Southern Chile during the 27 February 2010 Maule Earthquake
Authors: Brunet Santiago , de la Llera Juan Carlos , Jacobsen Andrés , Miranda Eduardo , Meza Cristián
Published: September 2012

This article describes the seismic performance of a group of ports in southern Chile during the 27 February 2010 Maule, Chile, earthquake. Direct costs in damage for these ports have been estimated in slightly less than US$300 million. Similarly to the performance of other ports in previous earthquakes, the most common failures observed were soil related, and include soil liquefaction, lateral spreading, and pile failures. Structural failures were mostly due to short pile effects and natural torsion. This situation is contrasted herein with the performance of the South Coronel Pier, which was seismically isolated in 2007. The isolated portion of this port remained operational after the earthquake, which was the main design goal. Post-earthquake preliminary analyses indicate that the structure was subjected to deformations and forces of approximately 60% to 70% of their design values, respectively. Piles and superstructure remained within elastic range, while the isolators experienced important nonlinear deformations.
Performance of Precast Concrete Building Structures
Authors: Ghosh S. K. , Cleland Ned M.
Published: September 2012

The Precast/Prestressed Concrete Institute (PCI) sent an assessment team to Chile, which visited the areas affected by the 27 February 2010 earthquake between 26 and 30 April 2010. This paper reports on the team's observations on the performance of precast/prestressed concrete structures. The precast concrete building systems observed by the PCI team generally performed well. In some cases, the lateral force-resisting system performed satisfactorily, but the absence or weakness of diaphragm framing resulted in local failures. Overall, the PCI team found a mature and sophisticated precast concrete industry that has successfully considered and solved issues of earthquake resistance without some of the constraints imposed on U.S. practice by restrictive building code provisions.
Repair of an 18-Story Shear Wall Building Damaged in the 2010 Chile Earthquake
Authors: Sherstobitoff John , Cajiao Primo , Adebar Perry
Published: September 2012

Three transverse shear walls at one corner of an 18-story building in Santiago failed in flexural compression just below grade, causing the ground floor to drop 75 mm and the corner of the roof to displace laterally 185 mm. Cracking of walls and floor slabs caused significant building distortions. Nonlinear analyses of shear walls and floor slabs were used to understand the measured residual displacements and determine effective stiffnesses needed for a three-dimensional (3-D) model of the building. This model was used to estimate jacking forces needed to reposition the building. Existing cracks in shear walls were injected with epoxy, and fiber reinforced plastic (FRP) fabric was used to control new cracks. Instrumentation was used during jacking to monitor building movements, inclinations of walls and slabs, maximum compression and tension strains in walls, and crack widths. The building was repaired for less than 25% of the replacement cost and with much less impact on building habitants and the surrounding community.
Historic and Traditional Structures during the 2010 Chile Earthquake: Observations, Codes, and Conservation Strategies
Authors: D'Ayala Dina , Benzoni Gianmario
Published: September 2012

The Maule, Chile, earthquake of February 2010 affected the Central Valley stretching from north of Santiago to the Rio Bío-Bío in the south. The architectural heritage suffered considerable losses, with some buildings seriously damaged or partially collapsed even in Santiago and Valparaíso, areas less affected by the earthquake. Exposing the vulnerability of Chilean architectural heritage, this event has renewed the debate about the national attitude towards architectural preservation and conservation engineering. From the survey conducted by the authors, it emerged that many retrofit and repair techniques implemented following prior earthquakes in Chile resulted in ineffective performance in the February 2010 earthquake. Safety and preservation requirements that are regulated in countries with similar historic heritage are presented as viable alternatives to past approaches and are compared with the Chilean pre-code for earthen buildings, currently under development, which appears to embrace modern preservation philosophies. Suitable remedial strategies conclude the paper.
Structural Performance of Bridges in the Offshore Maule Earthquake of 27 February 2010
Authors: Buckle Ian , Hube Matias , Chen Genda , Yen Wen-Huei , Arias Juan
Published: September 2012

Of the nearly 12,000 highway bridges in Chile, approximately 300 were damaged in this earthquake, including 20 with collapsed spans. Typical failure modes include damage to connections between super- and substructures, unseating of spans in skewed bridges due to in-plane rotation, and unseated spans with some column damage due to permanent ground movement. Unusual failure modes include unseating of spans in straight bridges due to in-plane rotation, plate girder rupture due to longitudinal forces, scour and pier damage due to tsunami action, and collapse of a historic masonry bridge. The most common damage mode was the failure of super-to-substructure connections (shear keys, steel stoppers, and seismic bars), which is the most likely reason for the low incidence of column damage. Whereas the fuse-like behavior of these components is believed to have protected the columns, the lack of adequate seat widths led to the collapse, or imminent collapse, of many superstructures.
Structural Analysis of Selected Failures Caused by the 27 February 2010 Chile Tsunami
Authors: Robertson Ian , Chock Gary , Morla Juan
Published: September 2012

Following the 2010 Chile earthquake and tsunami, the authors participated in the EERI reconnaissance team that traveled to Chile to document damage and structural performance. The authors focused on tsunami damage following the earthquake. A summary of tsunami damage to structures is given. Based on a series of well-defined structural element failures at sites where inundation depth was measured, the team was able to evaluate the hydrodynamic loading required to cause these failures and derive estimated lower bound flow velocity overland during the event. It was estimated that the velocity exceeded 3.2 m/s in Talcahuano harbor and 4.3 m/s in the coastal town of Dichato. When found in proximity to damaged buildings and other larger structures of interest, these simple structures can serve as “flow surrogate instruments” to estimate the local flow velocity. Failure analysis of these simple structures indicated that the hydrodynamic loading estimates provided by FEMA P646 may be unconservative.
Response of Reinforced Concrete Buildings in Concepción during the Maule Earthquake
Authors: Westenenk Benjamín , de la Llera Juan Carlos , Besa Juan José , Jünemann Rosita , Moehle Jack , Lüders Carl , Inaudi José Antonio , Elwood Kenneth J. , Hwang Shyh-Jiann
Published: September 2012

Detailed observations are reported for eight shear wall buildings from the Concepción region that experienced severe damage during the 27 February 2010 Chile earthquake. The repetitive nature of some of the damage suggests that these field observations may be applicable to similar buildings elsewhere, whereas other damage may be unique. Several shear walls experienced failures that apparently started at the boundaries due to the high compression in these unconfined edges, and propagated into the wall web. Other walls, including horizontal and vertical wall segments in perforated walls, experienced shear failure. Damage also was observed in columns, beams, and coupling slabs. In most cases, the percentage of damaged elements was less than 10% of the lateral force-resisting elements of the building, suggesting that these structures were not capable of distributing damage. Several building indices are calculated, including vibration periods and regularity indices, for comparison with observed behavior.
Performance of Water Systems during the Maule Mw 8.8 Earthquake of 27 February 2010
Authors: Eidinger John M.
Published: September 2012

The Maule Mw 8.8 earthquake of 27 February 2010 impacted a number of water and wastewater lifelines. Ground shaking and liquefaction heavily damaged the Essbio water and wastewater systems, particularly in Concepción. Ground shaking destroyed more than 70 elevated water tanks in rural water systems built by the national government. A fire water tank collapsed at the Santiago Airport. There was damage to canals. Despite more than 3,000 repairs to other types of water pipe, the high-density polyethylene pipe used in the Concepción water distribution system was undamaged.
Short-Period Rupture Process of the 2010 Mw 8.8 Maule Earthquake in Chile
Authors: Ruiz Sergio , Madariaga Raúl , Astroza Maximiliano , Saragoni G. Rodolfo , Lancieri María , Vigny Christophe , Campos Jaime
Published: September 2012

The 2010 Maule earthquake is one of the largest events ever recorded with modern instruments. We used the continuous GPS (cGPS) records to invert for the kinematic rupture process using an elliptical sub-patch approximation. In agreement with previous inversions, the largest slip is found in the northern part of the rupture zone. By cross-correlating signals from cGPS and strong motion records (SM) located in the northern part of the rupture zone, we identified two distinct seismic pulses. Using the arrival time of these pulses, we propose a short-period (<20 s) rupture process, the zone where these pulses are generated is situated near 35.5°S, in agreement with the area with the highest seismic slip and maximum observed intensity. Finally, we compare the strong motion records at the same sites for the 1985 Mw 8 Valparaíso earthquake and the Maule earthquake. We found that spectral contents and duration of the records of these two events were very similar. Thus, at least in the northern part of the rupture, the Maule earthquake radiated high frequency waves like an Mw 8 earthquake.
Seismic Design and Construction Practices for RC Structural Wall Buildings
Authors: Massone Leonardo M. , Bonelli Patricio , Lagos René , Lüders Carl , Moehle Jack , Wallace John W.
Published: September 2012

Reinforced concrete buildings utilizing structural walls for lateral load resistance are the predominant form of construction in Chile for buildings over four stories. Typical buildings include a large number of walls, with ratios of wall cross-sectional area to floor plan area of roughly 3% in each principal direction. Based on the good performance of RC buildings in the March 1985 earthquake, requirements for closely spaced transverse reinforcement at wall boundaries were excluded when Chile adopted a new concrete code in 1996 based on ACI 318-95. In recent years, use of three-dimensional linear models along with modal response spectrum analysis has become common. Since 1985, nearly 10,000 new buildings have been permitted. Although the newer buildings have similar wall area to floor plan areas as older buildings, newer walls are thinner and buildings are taller, leading to significantly higher wall axial load ratios.
Reconnaissance of the Chilean Wine Industry Affected by the 2010 Chile Offshore Maule Earthquake
Authors: Zareian Farzin , Sampere Carlos , Sandoval Victor , McCormick David L. , Moehle Jack , Leon Roberto
Published: September 2012

This paper summarizes the EERI reconnaissance team findings on damage to the Chilean wine industry after the 27 February 2010 Offshore Maule Earthquake. Wine production is one of the major industries in Chile, with an annual production of approximately one million metric tons. It is estimated that the total loss to the wine industry is over 125 million liters, with infrastructure damage estimated as high as US$430. Most of the damage was concentrated in older wineries with collapse of adobe walls and timber roofs or ribbed brick vaults. Damage to steel fermentation tanks was widespread among all wineries visited with the severity of such damage depending on the type of tank anchorage. Local buckling of legs in legged tanks or excessive movement followed by the tank falling off the support pad led to toppling that ruptured piping or valves. Stacked barrels, stored bottles of wine, and production lines were also damaged.
Quantification of Lifeline System Interdependencies after the 27 February 2010 Mw 8.8 Offshore Maule, Chile, Earthquake
Authors: Dueñas-Osorio Leonardo , Kwasinski Alexis
Published: September 2012

Data on lifeline system service restoration is seldom exploited for the calibration of performance prediction models or for response comparisons across systems and events. This study explores utility restoration curves after the 2010 Chilean earthquake through a time series method to quantify coupling strengths across lifeline systems. When consistent with field information, cross-correlations from restoration curves without significant lag times quantify operational interdependence, whereas those with significant lags reveal logistical interdependence. Synthesized coupling strengths are also proposed to incorporate cross-correlations and lag times at once. In the Chilean earthquake, coupling across fixed and mobile phones was the strongest per region followed by coupling within and across telecommunication and power systems in adjacent regions. Unapparent couplings were also revealed among telecommunication and power systems with water networks. The proposed methodology can steer new protocols for post-disaster data collection, including anecdotal information to evaluate causality, and inform infrastructure interdependence effect prediction models.
Identification of a Signaling Axis HIF-1α/MicroRNA-210/ISCU Independent of SDH Mutation That Defines a Subgroup of Head and Neck Paragangliomas
Authors: Merlo Anna , de Quiros Sandra Bernaldo , Secades Pablo , Zambrano Iriana , Balbín Milagros , Astudillo Aurora , Scola Bartolomé , Arístegui Miguel , Suarez Carlos , Chiara María-Dolores
Published: September 2012

Background:

Head and neck paragangliomas (HNPGLs) are rare tumors associated with the parasympathetic nervous system. Most are sporadic, but about one third result from germline mutations in succinate dehydrogenase (SDH) genes (SDHB, SDHC, SDHD, SDHA, or SDHAF2). Although a molecular connection between SDH dysfunction and tumor development is still unclear, the most accepted hypothesis proposes a central role of the pseudohypoxic pathway. SDH dysfunction induces abnormal stabilization of the hypoxia-inducible factors (HIFs) that regulate target genes involved in proliferation, apoptosis, angiogenesis, and metabolism. The involvement of these pathways in the development of sporadic HNPGLs is presently unknown.

Objective:

To get some insights into the hypoxic/pseudohypoxic molecular basis of HNPGLs, we attempted to define the gene, microRNA (miRNA), and HIF-1α expression patterns that distinguish tumors from normal paraganglia tissue.

Design:

Genome microarray and TaqMan low-density arrays were used to analyze gene and miRNA expression, respectively, in 17 HNPGL tumor tissues and three normal human carotid bodies. Twelve HNPGLs were used for validation of data. HIF-1α, SDHB, and iron-sulfur cluster scaffold protein (ISCU) protein expression was analyzed by immunohistochemistry.

Results:

We found activation of a canonical HIF-1α-related gene expression signaling only in a subset of HNPGLs from patients that did not harbor germline or somatic SDH mutations. The pseudohypoxic signature consisted in the overexpression of both HIF-1α-target genes and the HIF-1α-inducible miRNA, miR-210, and down-regulation of the miR-210 target gene, ISCU1/2. A decreased level of the iron-sulfur-containing protein SDHB was found by immunohistochemical analysis performed in two of these tumors.

Conclusions:

Collectively, this study unveiled a putative signaling axis of HIF-1α/miRNA-210/ISCU in a subset of HNPGLs that could have an impact on SDHB protein stability by a mechanism independent of SDH mutations, thus providing a foundation to better understand the functional interplay between HIF, miR-210, and mitochondria and its relevance in the pathogenesis of HNPGLs.
Fibronectin and stem cell differentiation – lessons from chondrogenesis
Authors: Singh Purva , Schwarzbauer Jean E.
Published: September 2012

The extracellular matrix (ECM) is an intricate network of proteins that surrounds cells and has a central role in establishing an environment that is conducive to tissue-specific cell functions. In the case of stem cells, this environment is the stem cell niche, where ECM signals participate in cell fate decisions. In this Commentary, we describe how changes in ECM composition and mechanical properties can affect cell shape and stem cell differentiation. Using chondrogenic differentiation as a model, we examine the changes in the ECM that occur before and during mesenchymal stem cell differentiation. In particular, we focus on the main ECM protein fibronectin, its temporal expression pattern during chondrogenic differentiation, its potential effects on functions of differentiating chondrocytes, and how its interactions with other ECM components might affect cartilage development. Finally, we discuss data that support the possibility that the fibronectin matrix has an instructive role in directing cells through the condensation, proliferation and/or differentiation stages of cartilage formation.
Comparative phenotypic analysis of the two major splice isoforms of phosphatidylinositol phosphate kinase type Iγ in vivo
Authors: Legate Kyle R. , Montag Dirk , Böttcher Ralph T. , Takahashi Seiichiro , Fässler Reinhard
Published: September 2012

Localized production of polyphosphoinositides is critical for their signaling function. To examine the biological relevance of specific pools of phosphatidylinositol 4,5-bisphosphate we compared the consequences of genetically ablating all isoforms of phosphatidylinositol phosphate (PIP) kinase type Iγ (PIPKIγ), encoded by the gene Pip5k1c, versus ablation of a specific splice isoform, PIPKIγ_i2, with respect to three reported PIPKIγ functions. Ablation of PIPKIγ_i2 caused a neuron-specific endocytosis defect similar to that found in PIPKIγ−/− mice, while agonist-induced calcium signaling was reduced in PIPKIγ−/− cells, but was not affected in the absence of PIPKIγ_i2. A reported contribution of PIPKIγ to epithelial integrity was not evident in PIPKIγ−/− mice. Given that mice lacking PIPKIγ_i2 live a normal lifespan whereas PIPKIγ−/− mice die shortly after birth, we propose that PIPKIγ-mediated metabotropic calcium signaling may represent an essential function of PIPKIγ, whereas functions specific to the PIPKIγ_i2 splice isoform are not essential for survival.
Transcriptional regulation of Profilin during wound closure in Drosophila larvae
Authors: Brock Amanda R. , Wang Yan , Berger Susanne , Renkawitz-Pohl Renate , Han Violet C. , Wu Yujane , Galko Michael J.
Published: September 2012

Injury is an inevitable part of life, making wound healing essential for survival. In postembryonic skin, wound closure requires that epidermal cells recognize the presence of a gap and change their behavior to migrate across it. In Drosophila larvae, wound closure requires two signaling pathways [the Jun N-terminal kinase (JNK) pathway and the Pvr receptor tyrosine kinase signaling pathway] and regulation of the actin cytoskeleton. In this and other systems, it remains unclear how the signaling pathways that initiate wound closure connect to the actin regulators that help execute wound-induced cell migrations. Here, we show that chickadee, which encodes the Drosophila Profilin, a protein important for actin filament recycling and cell migration during development, is required for the physiological process of larval epidermal wound closure. After injury, chickadee is transcriptionally upregulated in cells proximal to the wound. We found that JNK, but not Pvr, mediates the increase in chic transcription through the Jun and Fos transcription factors. Finally, we show that chic-deficient larvae fail to form a robust actin cable along the wound edge and also fail to form normal filopodial and lamellipodial extensions into the wound gap. Our results thus connect a factor that regulates actin monomer recycling to the JNK signaling pathway during wound closure. They also reveal a physiological function for an important developmental regulator of actin and begin to tease out the logic of how the wound repair response is organized.
Single cell analysis of Daxx and ATRX-dependent transcriptional repression
Authors: Newhart Alyshia , Rafalska-Metcalf Ilona U , Yang Tian , Negorev Dmitri G , Janicki Susan M
Published: September 2012

Histone H3.3 is a constitutively expressed H3 variant implicated in the epigenetic inheritance of chromatin structures. Recently, the PML-nuclear body (PML-NB)/Nuclear Domain 10 (ND10) proteins, Daxx and ATRX, were found to regulate replication-independent histone H3.3 chromatin assembly at telomeres and pericentric heterochromatin. As it is not completely understood how PML-NBs/ND10s regulate transcription and resistance to viral infection, we have used a CMV-promoter-regulated inducible transgene array, at which Daxx and ATRX are enriched, to delineate the mechanisms through which they regulate transcription. When integrated into HeLa cells, which express both Daxx and ATRX, the array is refractory to activation. However, transcription can be induced when ICP0, the HSV-1 E3 ubiquitin ligase required to reverse latency, is expressed. As ATRX and Daxx are depleted from the activated array in ICP0-expressing HeLa cells, this suggests that they are required to maintain a repressed chromatin environment. As histone H3.3 is strongly recruited to the ICP0-activated array but does not co-localize with the DNA, this also suggests that chromatin assembly is blocked during activation. The conclusion that the Daxx and ATRX pathway is required for transcriptional repression and chromatin assembly at this site is further supported by the finding that an array integrated into the ATRX-negative U2OS cell line can be robustly activated and that histone H3.3 is similarly recruited and unincorporated into the chromatin. Therefore, this study has important implications for understanding gene silencing, viral latency and PML-NB/ND10 function.
Molecular mechanisms regulating the establishment of hepatocyte polarity during human hepatic progenitor cell differentiation into a functional hepatocyte-like phenotype
Authors: Hua Mingxi , Zhang Weitao , Li Weihong , Li Xueyang , Liu Baoqing , Lu Xin , Zhang Haiyan
Published: September 2012

The correct functioning of hepatocytes requires the establishment and maintenance of hepatocyte polarity. However, the mechanisms regulating the generation of hepatocyte polarity are not completely understood. The differentiation of human fetal hepatic progenitor cells (hFHPCs) into functional hepatocytes provides a powerful in vitro model system for studying the molecular mechanisms governing hepatocyte development. In this study, we used a two-stage differentiation protocol to generate functional polarized hepatocyte-like cells (HLCs) from hFHPCs. Global gene expression profiling was performed on triplicate samples of hFHPCs, immature-HLCs and mature-HLCs. When the differential gene expression was compared based on the differentiation stage, a number of genes were identified that might be essential for establishing and maintaining hepatocyte polarity. These genes include those that encode actin filament-binding protein, protein tyrosine kinase activity molecules, and components of signaling pathways, such as PTK7, PARD3, PRKCI and CDC42. Based on known and predicted protein-protein interactions, the candidate genes were assigned to networks and clustered into functional categories. The expression of several of these genes was confirmed using real-time RT-PCR. By inactivating genes using small interfering RNA, we demonstrated that PTK7 and PARD3 promote hepatic polarity formation and affect F-actin organization. These results provide unique insight into the complex process of polarization during hepatocyte differentiation, indicating key genes and signaling molecules governing hepatocyte differentiation.
The SUMO ligase PIAS1 regulates UV-induced apoptosis by recruiting Daxx to SUMOylated foci
Authors: Sudharsan Raghavi , Azuma Yoshiaki
Published: September 2012

The small ubiquitin-like modifier (SUMO) ligase PIAS1 (Protein Inhibitor of Activated Stat-1) has been shown to play a role in cellular stress response by SUMOylating several proteins that are involved in DNA repair, apoptosis and transcription. In this paper, we show that PIAS1 regulates ultraviolet (UV)-induced apoptosis by recruiting Death-associated protein 6 (Daxx) to PIAS1-generated SUMO-foci. Cells that ectopically express PIAS1, but not other PIASes, show increased sensitivity to UV irradiation, suggesting that PIAS1 has a distinct function in UV-dependent apoptosis. Domain analysis of PIAS1 indicates that both PIAS1 SUMO-ligase activity and the specific localization of PIAS1 through its N-terminal and C-terminal domains are essential for UV-induced cell death. Daxx colocalizes with PIAS1-generated SUMOylated foci, and the reduction of Daxx using RNAi alleviates UV-induced apoptosis in PIAS1-expressing cells. PIAS1-mediated recruitment of Daxx and apoptosis following UV irradiation are dependent upon the Daxx C-terminal SUMO-interacting motif (SIM). Overall, our data suggest that the pro-apoptotic protein Daxx specifically interacts with one or more substrates SUMOylated by PIAS1 and this interaction leads to apoptosis following UV irradiation.
A key phosphorylation site in AC8 mediates regulation of Ca2+-dependent cAMP dynamics by an AC8–AKAP79–PKA signalling complex
Authors: Willoughby Debbie , Halls Michelle L. , Everett Katy L. , Ciruela Antonio , Skroblin Philipp , Klussmann Enno , Cooper Dermot M. F.
Published: September 2012

Adenylyl cyclase (AC) isoforms can participate in multimolecular signalling complexes incorporating A-kinase anchoring proteins (AKAPs). We recently identified a direct interaction between Ca2+-sensitive AC8 and plasma membrane-targeted AKAP79/150 (in cultured pancreatic insulin-secreting cells and hippocampal neurons), which attenuated the stimulation of AC8 by Ca2+ entry (Willoughby et al., 2010). Here, we reveal that AKAP79 recruits cAMP-dependent protein kinase (PKA) to mediate the regulatory effects of AKAP79 on AC8 activity. Modulation by PKA is a novel means of AC8 regulation, which may modulate or apply negative feedback to the stimulation of AC8 by Ca2+ entry. We show that the actions of PKA are not mediated indirectly via PKA-dependent activation of protein phosphatase 2A (PP2A) B56δ subunits that associate with the N-terminus of AC8. By site-directed mutagenesis we identify Ser-112 as an essential residue for direct PKA phosphorylation of AC8 (Ser-112 lies within the N-terminus of AC8, close to the site of AKAP79 association). During a series of experimentally imposed Ca2+ oscillations, AKAP79-targeted PKA reduced the on-rate of cAMP production in wild-type but not non-phosphorylatable mutants of AC8, which suggests that the protein–protein interaction may provide a feedback mechanism to dampen the downstream consequences of AC8 activation evoked by bursts of Ca2+ activity. This fine-tuning of Ca2+-dependent cAMP dynamics by targeted PKA could be highly significant for cellular events that depend on the interplay of Ca2+ and cAMP, such as pulsatile hormone secretion and memory formation.
RIN1 orchestrates the activation of RAB5 GTPases and ABL tyrosine kinases to determine the fate of EGFR
Authors: Balaji Kavitha , Mooser Chelsea , Janson Christine M. , Bliss Joanne M. , Hojjat Houmehr , Colicelli John
Published: September 2012

Stimulation of epidermal growth factor receptor (EGFR) initiates RAS signaling simultaneously with EGFR internalization. Endocytosed EGFR is then either recycled or degraded. EGFR fate is determined in part by the RAS effector RIN1, a guanine nucleotide exchange factor (GEF) for RAB5 GTPases. EGFR degradation was slowed by RIN1 silencing, enhanced by RIN1 overexpression and accelerated by RIN1 localization to the plasma membrane. RIN1 also directly activates ABL tyrosine kinases, which regulate actin remodeling, a function not previously connected to endocytosis. We report that RIN1-RAB5 signaling favors EGFR downregulation over EGFR recycling, whereas RIN1-ABL signaling stabilizes EGFR and inhibits macropinocytosis. RIN1QM, a mutant that blocks ABL activation, caused EGF-stimulated membrane ruffling, actin remodeling, dextran uptake and EGFR degradation. An ABL kinase inhibitor phenocopied these effects in cells overexpressing RIN1. EGFR activation also promotes RIN1 interaction with BIN1, a membrane bending protein. These findings suggest that RIN1 orchestrates RAB5 activation, ABL kinase activation and BIN1 recruitment to determine EGFR fate.
Lipid class and depth-specific thermal properties in the blubber of two species of odontocete cetaceans, the short-finned pilot whale (Globicephala macrorhynchus) and the pygmy sperm whale (Kogia breviceps)
Authors: Bagge Laura E. , Koopman Heather N. , Rommel Sentiel A. , McLellan William A. , Pabst D. A.
Published: September 2012

Blubber, the specialized hypodermis of cetaceans, provides thermal insulation through the quantity and quality of lipids it contains. Quality refers to % lipid content; however, not all lipids are the same. Certain deep-diving cetacean groups possess blubber with lipids - wax esters (WE) - that are not typically found in mammals, and the insulative quality of “waxy” blubber is unknown. Our study explored the influence of lipid storage class – specifically WE in pygmy sperm whales (Kogia breviceps; n=7) and typical mammalian triacylglycerols (TAG) in short-finned pilot whales (Globicephala macrorhynchus; n=7) – on blubber’s thermal properties. Although the blubber of both species had similar total lipid contents, the thermal conductivity of G. macrorhynchus blubber (0.20 ± 0.01 Wm-1°C-1) was significantly higher than that of K. breviceps (0.15 ± 0.01 Wm-1°C-1; P=0.0006). These results suggest that lipid class significantly influences blubber’s ability to resist heat flow. In addition, because blubber’s lipid content is known to be stratified, we measured its depth-specific thermal conductivities. In K. breviceps blubber, the depth-specific conductivity values tended to vary inversely with lipid content. In contrast, G. macrorhynchus blubber displayed unexpected depth-specific relationships between lipid content and conductivity, which suggests that temperature-dependent effects, such as melting, may be occurring. Differences in heat flux measurements across the depth of the blubber samples provide evidence that both species are capable of storing heat in their blubber. The function of blubber as an insulator is complex and may rely upon its lipid class, stratified composition, and dynamic heat storage capabilities.
The pro-apoptotic action of the peptide hormone, Neb-colloostatin, on insect haemocytes
Authors: Czarniewska Elżbieta , Mrówczyńska Lucyna , Kuczer Mariola , Rosiński Grzegorz
Published: September 2012

The gonadoinhibitory peptide hormone, Neb-colloostatin, was first isolated from ovaries of the flesh fly Neobellieria bullata. This 19-mer peptide is thought to be a cleaved product of a collagen-like precursor molecule that is formed during remodelling of the extracellular matrix. In this study, we report that upon injection of pico- and nanomolar doses, this peptide exerts a pro-apoptotic action on haemocytes of Tenebrio molitor adults, as visualized by changes in morphology and viability. The F-actin cytoskeleton was found aggregating into distinctive patches. This may be responsible for the observed inhibition of adhesion of haemocytes and for the stimulation of filopodia formation. However, Neb-colloostatin injection did not induce the formation of authophagic vacuoles. Our results suggest that physiological concentrations of Neb-colloostatin may play an important role in controlling the quantity and activity of haemocytes in insect haemolymph. They also suggest that in periods that Neb-colloostatin is released, this peptide may cause a weakening of the insects' immune system. This is the first report that exposure to a peptide hormone causes apoptosis in insect haemocytes.
Quadrupedal gaits in hexapod animals - inter-leg coordination in free-walking adult stick insects
Authors: Grabowska Martyna , Godlewska Elzbieta , Schmidt Joachim , Daun-Gruhn Silvia
Published: September 2012

The analysis of inter-leg coordination in insect walking is generally a study of six-legged locomotion. Since decades the stick insect Carausius morosus is instrumental for unraveling rules and mechanisms that control leg coordination in hexapeds. We analyzed inter-leg coordination in Carausius morosus that walked freely straight paths on plane surfaces with different slopes. Consecutive 1.7 second sections were assigned inter-leg coordination patterns (gaits) based on foot fall patterns. Regular gaits, i.e. wave, tetrapod or tripod gaits occurred depending on surface slopes. Most often tetrapod gaits were observed, wave gaits only occurred on 90° inclining slopes and tripod gaits most often on 15° declining slopes, i.e. in 40% of sections. Depending on slope 36% to 66% of sections were assigned irregular gaits. Irregular gaits were mostly due to multiple stepping in front legs, which is perhaps probing behavior, not phase coupled to middle legs’ cycles. In irregular gaits middle and hind leg coordination was regular, related to quadrupedal walk and wave gaits. Apparently front legs uncouple from and couple into the walking system without compromising middle and hind leg coordination. In front leg amputee remaining legs are strictly coordinated. In hind and middle leg amputees front legs continued multiple stepping. Middle leg amputees’ coordination was maladapted with front and hind legs performing multiple stepping or ipsilateral legs being in simultaneous swing. Thus, afferent information from middle legs might be necessary for a regular hind leg stepping pattern.
Swimming away or clamming up: the use of phasic and tonic adductor muscles during escape responses varies with shell morphology in scallops
Authors: Tremblay Isabelle , Guderley Helga E. , Himmelman John H.
Published: September 2012

The simple locomotor system of scallops facilitates study of muscle use during locomotion. We compared five species of scallops with different shell morphologies to see whether shell morphology and muscle use change in parallel or whether muscle use can compensate for morphological constraints. Force recordings during escape responses revealed that the use of tonic and phasic contractions varied markedly among species. The active species, Amusium balloti, Placopecten magellanicus and Pecten fumatus, made more phasic contractions than the more sedentary species, Mimachlamys asperrima and Crassadoma gigantea. Tonic contractions varied considerably among these species, with the two more sedentary species often starting their response to the predator with a tonic contraction and the more active species using shorter tonic contractions between series of phasic contractions. P. magellanicus made extensive use of short tonic contractions. P. fumatus mounted an intense series of phasic contractions at the start of its response, perhaps to overcome the constraints of its unfavourable shell morphology. Valve closure by the more sedentary species suggests that their shell morphology protects against predation, whereas swimming by the more active species relies upon intense phasic contractions together with favourable shell characteristics.
Predictive saccade in the absence of smooth pursuit: interception of moving targets in the archer fish
Authors: Ben-Simon Avi , Ben-Shahar Ohad , Vasserman Genadiy , Segev Ronen
Published: September 2012

Interception of fast moving targets is a demanding task many animals solve. To handle it successfully, mammals employ both saccadic and smooth pursuit eye movements in order to confine the target to their area centralis. But how can non-mammalian vertebrates, which lack smooth pursuit, intercept moving targets? We studied this question by exploring eye movement strategies employed by archer fish, an animal that possesses an area centralis, lacks smooth pursuit eye movements, but can intercept moving targets by shooting jets of water at them. We tracked gaze direction of fish during interception of moving targets and found that they employ saccadic eye movements based on prediction of target position when it is hit. The fish fixates on the target’s initial position for ~ 0.2 sec from the onset of its motion, a time period used to predict if a shot can be made before the projection of the target exits the area centralis. If the prediction indicates otherwise, the fish performs a saccade that overshoots the center of gaze beyond the present target projection on the retina, such that after the saccade the moving target remains inside the area centralis long enough to prepare and perform a shot. These results add to the growing body of knowledge on biological target tracking and may shed light on the mechanism underlying this behavior in other animals with no neural system for generation of smooth pursuit eye movements.
Intelligent Button Developed Using Smart Soft and Wet Materials
Authors: Harada Sho , Hidema Ruri , Gong Jin , Furukawa Hidemitsu
Published: September 2012

A novel push button is developed using shape-memory gels (SMGs). The Young’s modulus of SMGs changes dramatically with temperature. This modulus change is utilized to control the input-acceptable and input-not-acceptable states of the button. We believe the mechanism of this button could be used to develop new devices, especially for the visually impaired.
The Mirrlees Review and the State of Public Economics
Authors: Atkinson Anthony B
Published: September 2012

The Mirrlees Review of taxation in the United Kingdom is a landmark in the analysis of U.K. fiscal policy, and of wide interest to public finance economists around the world. This review concentrates on what we can learn from the Review about the current state of public economics and directions for future research. (JEL E62, H20, H50)
Paediatric reference values for the C-terminal fragment of fibroblast-growth factor-23, sclerostin, bone-specific alkaline phosphatase and isoform 5b of tartrate-resistant acid phosphatase
Authors: Fischer Dagmar-Christiane , Mischek Anne , Wolf Sabrina , Rahn Anja , Salweski Birgit , Kundt Guenther , Haffner Dieter
Published: September 2012

Background

Paediatric reference values for novel markers of phosphate homeostasis, bone formation and resorption and their putative relationship to growth are lacking.

Methods

A total of 424 healthy children, adolescents and young adults (221 males) aged 0.1–21 y, were enrolled in this cross-sectional study. Height, weight and height velocity were assessed. Plasma/serum samples for determination of C-terminal fragment of fibroblast growth factor-23 (cFGF-23), sclerostin, bone alkaline phosphatase (BAP) and tartrate-resistant acid phosphatase 5b (TRAP5b) were available from 222, 264, 352 and 338 individuals, respectively. Calculation of cross-sectional centiles and z-scores was based on median (M), standard coefficient of variation (S) and the Box-Cox power (L) of transformation (LMS method) per age cohort. Correlations between variables as well as with growth were assessed.

Results

cFGF-23, BAP and TRAP5b were significantly correlated with age (each P < 0.01), with highest values during infancy and adolescence. Serum levels of BAP and TRAP5b were significantly higher in adolescent boys compared with girls (each P < 0.01). In contrast, sclerostin levels were independent of age and gender. BAP and TRAP5b were strongly correlated and both were significantly associated with cFGF-23 and sclerostin as well (each P < 0.01). cFGF-23 was positively correlated with serum phosphate and renal phosphate threshold concentration (each P < 0.01). Height, weight, body mass index and height velocity were weakly correlated with BAP and TRAP5b (each P < 0.05).

Conclusions

This study provides age- and gender-related centile charts and z-scores for cFGF-23, BAP, TRAP5b and sclerostin and highlights the link between phosphate homeostasis and markers of bone metabolism during growth.
An observational study to evaluate the efficiency and safety of ioversol pre-filled syringes compared with ioversol bottles in contrast-enhanced examinations
Authors: Vogl Thomas J , Wessling Johannes , Buerke Boris
Published: September 2012

Background

The use of pre-filled syringes for contrast media (CM) administration allows efficient and optimized workflow during radiologic diagnostic procedures, and reduces the risk of contamination, providing benefits for both patients and healthcare workers.

Purpose

To compare the efficiency and safety of ioversol (OptirayTM) bottles and pre-filled syringes in clinical practice.

Material and Methods

This was an observational, non-interventional, prospective, multicenter study conducted at 72 centers in Germany. Patients undergoing contrast-enhanced computed tomography (CT) examinations with ioversol were enrolled. The use of ioversol bottles and pre-filled syringes in the diagnostic procedure was recorded in terms of efficiency (residual volume, re-use of CM) and safety (adverse events [AEs]).

Results

A total of 10,836 patients were enrolled and included in this study. Ioversol bottles and syringes were used in 72% and 28% of cases, respectively. Analysis of the volume of CM in bottles before and after examinations, together with the volume used during the examination, suggested that in 22.5% of cases a new bottle was connected during the procedure. Further analysis revealed that in 80.2% of cases, the remaining volume of CM in the bottles could potentially be used for subsequent investigations, compared with <1% of cases for pre-filled syringes. For the total study population, AEs and serious AEs were reported in 30 (0.28%) and four (0.037%) patients, respectively, with no significant difference observed between ioversol bottles and syringes.

Conclusion

Administration of ioversol for contrast-enhanced CT examinations is associated with a low incidence of AEs and is generally safe and well tolerated. Ioversol pre-filled syringes were associated with lower residual volumes and less potential re-use compared with bottles.