bluuebunny/crossref_metadata_2025 huggingface dataset:
Platelet-derived growth factor (PDGF)-BB-mediated induction of monocyte chemoattractant protein 1 in human astrocytes: implications for HIV-associated neuroinflammation
Authors: Bethel-Brown Crystal , Yao Honghong , Hu Guoku , Buch Shilpa
Published: December 2012

Chemokine (C-C motif) ligand 2, also known as monocyte chemoattractant protein 1 (MCP-1) is an important factor for the pathogenesis of HIV-associated neurocognitive disorders (HAND). The mechanisms of MCP-1-mediated neuropathogenesis, in part, revolve around its neuroinflammatory role and the recruitment of monocytes into the central nervous system (CNS) via the disrupted blood-brain barrier (BBB). We have previously demonstrated that HIV-1/HIV-1 Tat upregulate platelet-derived growth factor (PDGF)-BB, a known cerebrovascular permeant; subsequently, the present study was aimed at exploring the regulation of MCP-1 by PDGF-BB in astrocytes with implications in HAND. Specifically, the data herein demonstrate that exposure of human astrocytes to HIV-1 LAI elevated PDGF-B and MCP-1 levels. Furthermore, treating astrocytes with the human recombinant PDGF-BB protein significantly increased the production and release of MCP-1 at both the RNA and protein levels. MCP-1 induction was regulated by activation of extracellular-signal-regulated kinase (ERK)1/2, c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein (MAP) kinases and phosphatidylinositol 3-kinase (PI3K)/Akt pathways and the downstream transcription factor, nuclear factor κB (NFκB). Chromatin immunoprecipitation (ChIP) assays demonstrated increased binding of NFκB to the human MCP-1 promoter following PDGF-BB exposure. Conditioned media from PDGF-BB-treated astrocytes increased monocyte transmigration through human brain microvascular endothelial cells (HBMECs), an effect that was blocked by STI-571, a tyrosine kinase inhibitor (PDGF receptor (PDGF-R) blocker). PDGF-BB-mediated release of MCP-1 was critical for increased permeability in anin vitroBBB model as evidenced by blocking antibody assays. Since MCP-1 is linked to disease severity, understanding its modulation by PDGF-BB could aid in understanding the proinflammatory responses in HAND. These results suggest that astrocyte activation by PDGF-BB exaggerates monocyte recruitment into the brain via MCP-1 and underscores the critical role astrocytes play in HAND.
Non-Peptidergic Primary Afferents are Presynaptic to Neurokinin-1 Receptor Immunoreactive Lamina I Projection Neurons in Rat Spinal Cord
Authors: Saeed Abeer W , Ribeiro-da-Silva Alfredo
Published: December 2012

Background:

Pain-related (nociceptive) information is carried from the periphery to the dorsal horn of the spinal cord mostly by two populations of small diameter primary afferents, the peptidergic and the non-peptidergic. The peptidergic population expresses neuropeptides, such as substance P and calcitonin gene-related peptide, while the non-peptidergic fibers are devoid of neuropeptides, express the purinergic receptor P2X3, and bind the isolectin B4 (IB4). Although it has been known for some time that in rat the peptidergic afferents terminate mostly in lamina I and outer lamina II and non-peptidergic afferents in inner lamina II, the extent of the termination of the latter population in lamina I was never investigated as it was considered as very minor. Because our preliminary evidence suggested otherwise, we decided to re-examine the termination of non-peptidergic afferents in lamina I, in particular with regards to their innervation of projection neurons expressing substance P receptors (NK-1r). We used retrograde labeling of neurons from the parabrachial nucleus combined with lectin IB4 binding and immunocytochemistry. Samples were examined by confocal and electron microscopy.

Results:

By confocal microscopy, we studied the termination of non-peptidergic afferents in lamina I using IB4 binding and P2X3 immunoreactivity as markers, in relation to CGRP immunoreactivy, a marker of peptidergic afferents. The number of IB4 or P2X3-labeled fibers in lamina I was higher than previously thought, although they were less abundant than CGRP-labeled afferents. There were very few fibers double-labeled for CGRP and either P2X3 or IB4. We found a considerable number of IB4-positive fiber varicosities in close apposition to NK-1r-positive lamina I projection neurons, which were distinct from peptidergic varicosities. Furthermore, we confirmed at the ultrastructural level that there were bona fide synapses between P2X3-immunoreactive non-peptidergic boutons and neurokinin-1 receptor-positive lamina I dendrites.

Conclusions:

These results indicate the presence of direct innervation by non-peptidergic nociceptive afferents of lamina I projection neurons expressing NK-1r. Further investigations are needed to better understand the role of these connections in physiological conditions and chronic pain states.
Immunohistochemical characterization of neoplastic cells of breast origin
Authors: Noriega Maria de las Mercedes , Paesani Fernando , Perazzo Florencia , Lago Néstor , Krupitzki Hugo , Nieto Silvana , Garcia Alejandro , Avagnina Alejandra , Elsner Boris , Denninghoff Valeria Cecilia ,   Miembro de la Carrera de Investigador del Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)
Published: December 2012

Background

After skin cancer, breast cancer is the most common malignancy in women. Tumors of unknown origin account for 5-15% of malignant neoplasms, with 1.5% being breast cancer. An immunohistochemical panel with conventional and newer markers, such as mammaglobin, was selected for the detection of neoplastic cells of breast origin. The specific objectives are: 1) to determine the sensitivity and specificity of the panel, with a special emphasis on the inclusion of the mammaglobin marker, and 2) to compare immunohistochemistry performed on whole tissue sections and on Tissue Micro-Array.

Methods

Twenty-nine metastatic breast tumors were included and assumed as tumors of unknown origin. Other 48 biopsies of diverse tissues were selected and assumed as negative controls. Tissue Micro-Array was performed. Immunohistochemistry for mammaglobin, gross cystic disease fluid protein-15, estrogen receptor, progesterone receptor and cytokeratin 7 was done.

Results

Mammaglobin positive staining was observed in 10/29 cases, in 13/29 cases for gross cystic disease fluid protein-15, in 20/29 cases for estrogen receptor, in 9/29 cases for progesterone receptor, and in 25/29 cases for cytokeratin 7. Among the negative controls, mammaglobin was positive in 2/48, and gross cystic disease fluid protein-15 in 4/48.

Conclusions

The inclusion of MAG antibody in the immunohistochemical panel for the detection of tumors of unknown origin contributed to the detection of metastasis of breast cancer. The diagnostic strategy with the highest positive predictive value (88%) included hormone receptors and mammaglobin in serial manner.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1366310812718988
The class I PI3K/Akt pathway is critical for cancer cell survival in dogs and offers an opportunity for therapeutic intervention
Authors: Chen Yu-Ting , Tan Karen AL , Pang Lisa Y , Argyle David J
Published: December 2012

Background

Using novel small-molecular inhibitors, we explored the feasibility of the class I PI3K/Akt/mTORC1 signaling pathway as a therapeutic target in canine oncology either by using pathway inhibitors alone, in combination or combined with conventional chemotherapeutic drugs in vitro.

Results

We demonstrate that growth and survival of the cell lines tested are predominantly dependent on class I PI3K/Akt signaling rather than mTORC1 signaling. In addition, the newly developed inhibitors ZSTK474 and KP372-1 which selectively target pan-class I PI3K and Akt, respectively, and Rapamycin which has been well-established as highly specific mTOR inhibitor, decrease viability of canine cancer cell lines. All inhibitors demonstrated inhibition of phosphorylation of pathway members. Annexin V staining demonstrated that KP372-1 is a potent inducer of apoptosis whereas ZSTK474 and Rapamycin are weaker inducers of apoptosis. Simultaneous inhibition of class I PI3K and mTORC1 by ZSTK474 combined with Rapamycin additively or synergistically reduced cell viability whereas responses to the PI3K pathway inhibitors in combination with conventional drug Doxorubicin were cell line-dependent.

Conclusion

This study highlighted the importance of class I PI3K/Akt axis signaling in canine tumour cells and identifies it as a promising therapeutic target.
Internal vacuum-assisted closure device in the swine model of severe liver injury
Authors: Everett Christopher B , Thomas Bruce W , Moncure Michael
Published: December 2012

Objectives

The authors present a novel approach to nonresectional therapy in major hepatic trauma utilizing intraabdominal perihepatic vacuum assisted closure (VAC) therapy in the porcine model of Grade V liver injury.

Methods

A Grade V injury was created in the right lobe of the liver in a healthy pig. A Pringle maneuver was applied (4.5 minutes total clamp time) and a vacuum assisted closure device was placed over the injured lobe and connected to suction. The device consisted of a perforated plastic bag placed over the liver, followed by a 15 cm by 15cm VAC sponge covered with a nonperforated plastic bag. The abdomen was closed temporarily. Blood loss, cardiopulmonary parameters and bladder pressures were measured over a one-hour period. The device was then removed and the animal was euthanized.

Results

Feasibility of device placement was demonstrated by maintenance of adequate vacuum suction pressures and seal. VAC placement presented no major technical challenges. Successful control of ongoing liver hemorrhage was achieved with the VAC. Total blood loss was 625 ml (20ml/kg). This corresponds to class II hemorrhagic shock in humans and compares favorably to previously reported estimated blood losses with similar grade liver injuries in the swine model. No post-injury cardiopulmonary compromise or elevated abdominal compartment pressures were encountered, while hepatic parenchymal perfusion was maintained.

Conclusion

These data demonstrate the feasibility and utility of a perihepatic negative pressure device for the treatment of hemorrhage from severe liver injury in the porcine model.
The utility of recombinant factor VIIa as a last resort in trauma
Authors: Mamtani Rishi , Nascimento Bartolomeu , Rizoli Sandro , Pinto Ruxandra , Lin Yulia , Tien Homer
Published: December 2012

Introduction

The use of recombinant factor VII (rFVIIa) as a last resort for the management of coagulopathy when there is severe metabolic acidosis during large bleedings in trauma might be deemed inappropriate. The objective of this study was to identify critical degrees of acidosis and associated factors at which rFVIIa might be considered of no utility.

Methods

All massively transfused (≥ 8 units of red blood cells within 12 hours) trauma patients from Jan 2000 to Nov 2006. Demographic, baseline physiologic and rFVIIa dosage data were collected. Rate of red blood cell transfusion in the first 6 hours of hospitalization (RBC/hr) was calculated and used as a surrogate for bleeding. Last resort use of rFVIIa was defined by a pH≤ 7.02 based on ROC analysis for survival. In-hospital mortality was analyzed in last resort and non-last resort groups. Univariate analysis was performed to assess for differences between groups and identify factors associates with no utility of rFVIIa.

Results

71 patients who received rFVIIa were analyzed. The pH> 7.02 had 100% sensitivity for the identification of potential survivors. All 11 coagulopathic, severely acidotic (pH ≤ 7.02) patients with high rates of bleeding (4RBC/hr) died despite administration of rFVIIa. The financial cost of administering rFVIIa as a last resort to these 11 severely acidotic and coagulophatic cases was $75,162 (CA).

Conclusions

Our study found no utility of rFVIIa in treating severely acidotic, coagulopathic trauma patients with high rates of bleeding; and thus restrictions should be set on its usage in these circumstances.
Integrating many co-splicing networks to reconstruct splicing regulatory modules
Authors: Dai Chao , Li Wenyuan , Liu Juan , Zhou Xianghong Jasmine
Published: December 2012

Background

Alternative splicing is a ubiquitous gene regulatory mechanism that dramatically increases the complexity of the proteome. However, the mechanism for regulating alternative splicing is poorly understood, and study of coordinated splicing regulation has been limited to individual cases. To study genome-wide splicing regulation, we integrate many human RNA-seq datasets to identify splicing module, which we define as a set of cassette exons co-regulated by the same splicing factors.

Results

We have designed a tensor-based approach to identify co-splicing clusters that appear frequently across multiple conditions, thus very likely to represent splicing modules - a unit in the splicing regulatory network. In particular, we model each RNA-seq dataset as a co-splicing network, where the nodes represent exons and the edges are weighted by the correlations between exon inclusion rate profiles. We apply our tensor-based method to the 38 co-splicing networks derived from human RNA-seq datasets and indentify an atlas of frequent co-splicing clusters. We demonstrate that these identified clusters represent potential splicing modules by validating against four biological knowledge databases. The likelihood that a frequent co-splicing cluster is biologically meaningful increases with its recurrence across multiple datasets, highlighting the importance of the integrative approach.

Conclusions

Co-splicing clusters reveal novel functional groups which cannot be identified by co-expression clusters, particularly they can grant new insights into functions associated with post-transcriptional regulation, and the same exons can dynamically participate in different pathways depending on different conditions and different other exons that are co-spliced. We propose that by identifying splicing module, a unit in the splicing regulatory network can serve as an important step to decipher the splicing code.
Noninvasive Fetal Trisomy (NIFTY) test: an advanced noninvasive prenatal diagnosis methodology for fetal autosomal and sex chromosomal aneuploidies
Authors: Jiang Fuman , Ren Jinghui , Chen Fang , Zhou Yuqiu , Xie Jiansheng , Dan Shan , Su Yue , Xie Jianhong , Yin Baomin , Su Wen , Zhang Huakun , Wang Wei , Chai Xianghua , Lin Linhua , Guo Hui , Li Qiyun , Li Peipei , Yuan Yuying , Pan Xiaoyu , Li Yihan , Liu Lifu , Chen Huifei , Xuan Zhaoling , Chen Shengpei , Zhang Chunlei , Zhang Hongyun , Tian Zhongming , Zhang Zhengyu , Jiang Hui , Zhao Lijian , Zheng Weimou , Li Songgang , Li Yingrui , Wang Jun , Wang Jian , Zhang Xiuqing
Published: December 2012

Background

Conventional prenatal screening tests, such as maternal serum tests and ultrasound scan, have limited resolution and accuracy.

Methods

We developed an advanced noninvasive prenatal diagnosis method based on massively parallel sequencing. The Noninvasive Fetal Trisomy (NIFTY) test, combines an optimized Student’s t-test with a locally weighted polynomial regression and binary hypotheses. We applied the NIFTY test to 903 pregnancies and compared the diagnostic results with those of full karyotyping.

Results

16 of 16 trisomy 21, 12 of 12 trisomy 18, two of two trisomy 13, three of four 45, X, one of one XYY and two of two XXY abnormalities were correctly identified. But one false positive case of trisomy 18 and one false negative case of 45, X were observed. The test performed with 100% sensitivity and 99.9% specificity for autosomal aneuploidies and 85.7% sensitivity and 99.9% specificity for sex chromosomal aneuploidies. Compared with three previously reported z-score approaches with/without GC-bias removal and with internal control, the NIFTY test was more accurate and robust for the detection of both autosomal and sex chromosomal aneuploidies in fetuses.

Conclusion

Our study demonstrates a powerful and reliable methodology for noninvasive prenatal diagnosis.
Interleukin 12 receptor deficiency in a child with recurrent bronchopneumonia and very high IgE levels
Authors: Palamaro Loredana , Giardino Giuliana , Santamaria Francesca , Romano Rosa , Fusco Anna , Montella Silvia , Salerno Mariacarolina , Ursini Matilde Valeria , Pignata Claudio
Published: December 2012

Interleukin-12 (IL-12) is involved in cellular immune responses against intracellular pathogens by promoting the generation of T naive in T helper 1 (Th1) cells and by increasing interferon-gamma (IFN-gamma) production from T and natural killer (NK) cells. A defective induction of a Th1 response may lead to a higher risk of infections, and, in particular, infections due to typical and atypicalMycobacteria. We report on the case of a girl with suffering from recurrent bronchopneumonia associated with very high serum IgE levels, who exhibited a profound impairment of the Th1 generation associated with a novel mutation in the exon 5 of the IL-12R β1 gene (R156H). Our data suggest that in children with severe and recurrent infections, even in the absence of a mycobacterial infection, functional and/or genetic alterations of the molecular mechanisms governing Th1/Th2 homeostasis might be responsible for an atypical immunodeficiency and, therefore, should be investigated in these patients.
Effects and mechanism of duodenal-jejunal bypass and sleeve gastrectomy on GLUT2 and glucokinase in diabetic Goto–Kakizaki rats
Authors: Donglei Zhou , Liesheng Lu , Xun Jiang , Chenzhu Zhen , Weixing Ding
Published: December 2012

Background

The study investigated the effects and mechanism of duodenal-jejunal bypass (DJB) and sleeve gastrectomy (SG) on the expression of liver GLUT2 and glucokinase (GCK) in diabetic rats.

Methods

Animal models of Goto–Kakizaki (GK) rats were established for the investigation of DJB and SG. Results of weight, food intake, fasting plasma glucose level, oral glucose tolerance test and insulin were compared. Liver tissues were harvested 8 weeks postoperatively. Reverse transcription-PCR and western blot were used to detect liver GLUT2 and GCK mRNA and protein expression after operation.

Results

Fasting plasma glucose levels of DJB group and SG group in GK rats were markedly declined at 3 days and l, 2, 4, 6, and 8 weeks postoperatively (P < 0.01), whereas the levels of the sham-operated group only dropped at 3 days and 1 week postoperatively, and there were no significant differences 2 weeks postoperatively (P > 0.05). In the liver of GK rats, GLUT2 mRNA level and protein expression after DJB were higher than those in sham-operated group and control group. GLUT2 mRNA level and protein expression after SG were significantly lower than those in control group (P < 0.01). GCK mRNA and protein experienced similar expression change.

Conclusions

Both DJB and SG can decrease the plasma glucose levels of GK rats, whereas they have different effects on the expression of liver GLUT2 and GCK.
Functional Relationships Between Price and Volatility Jumps and Their Consequences for Discretely Observed Data
Authors: Jacod Jean , Klüppelberg Claudia , Müller Gernot
Published: December 2012

Many prominent continuous-time stochastic volatility models exhibit certain functional relationships between price jumps and volatility jumps. We show that stochastic volatility models like the Ornstein–Uhlenbeck and other continuous-time CARMA models as well as continuous-time GARCH and EGARCH models all exhibit such functional relations. We investigate the asymptotic behaviour of certain functionals of price and volatility processes for discrete observations of the price process on a grid, which are relevant for estimation and testing problems.
Approximating Quasistationary Distributions of Birth–Death Processes
Authors: Clancy Damian
Published: December 2012

For a sequence of finite state space birth–death processes, each having a single absorbing state, we show that, under certain conditions, as the size of the state space tends to infinity, the quasistationary distributions converge to the stationary distribution of a limiting infinite state space birth–death process. This generalizes a result of Keilson and Ramaswamy by allowing birth and death rates to depend upon the size of the state space. We give sufficient conditions under which the convergence result of Keilson and Ramaswamy remains valid. The generalization allows us to apply our convergence result to examples from population biology: a Pearl–Verhulst logistic population growth model and the susceptible-infective-susceptible (SIS) model for infectious spread. The limit distributions obtained suggest new finite-population approximations to the quasistationary distributions of these models, obtained by the method of cumulant closure. The new approximations are found to be both simple in form and accurate.
Asymptotics of Maxima of Strongly Dependent Gaussian Processes
Authors: Tan Zhongquan , Hashorva Enkelejd , Peng Zuoxiang
Published: December 2012

Let {Xn(t),t∈[0,∞)},n∈ℕ, be standard stationary Gaussian processes. The limit distribution oft∈[0,T(n)]|Xn(t)| is established asrn(t), the correlation function of {Xn(t),t∈[0,∞)},n∈ℕ, which satisfies the local and long-range strong dependence conditions, extending the results obtained in Seleznjev (1991).
Upper Deviations for Split Times of Branching Processes
Authors: Amini Hamed , Lelarge Marc
Published: December 2012

Upper deviation results are obtained for the split time of a supercritical continuous-time Markov branching process. More precisely, we establish the existence of logarithmic limits for the likelihood that the split times of the process are greater than an identified value and determine an expression for the limiting quantity. We also give an estimation for the lower deviation probability of the split times, which shows that the scaling is completely different from the upper deviations.
A Glaser Twist: Focus on the Mixture Parameters
Authors: Block Henry W. , Langberg Naftali A. , Savits Thomas H.
Published: December 2012

In this paper we introduce a variation on Glaser's method for determining the shape of the failure rate function of a mixture. It has often been seen that the shape of the failure rate depends on the mixing parameter q. Our method provides an explanation for this phenomenon. We then illustrate our technique with the mixture of an exponential and a gamma density for all possible cases.
DEADSouth protein localizes to germ plasm and is required for the development of primordial germ cells in Xenopus laevis
Authors: Yamaguchi Takeshi , Taguchi Ayaka , Watanabe Kenji , Orii Hidefumi
Published: December 2012

DEADSouth mRNA is a component of germ plasm in Xenopus laevis and encodes a DDX25 DEAD-box RNA helicase. To determine the intracellular localization of DEADSouth protein, we injected mRNA encoding DEADSouth tagged with mCherry fluorescent protein into fertilized eggs from transgenic Xenopus expressing EGFP fused with a mitochondrial targeting signal. The DEADSouth-mCherry fusion protein was localized to the germ plasm, a mitochondria-rich region in primordial germ cells (PGCs). DEADSouth overexpression resulted in a reduction of PGC numbers after stage 20. Conversely, DEADSouth knockdown using an antisense locked nucleic acid gapmer inhibited movement of the germ plasm from the cortex to the perinuclear region, resulting in inhibition of PGC division at stage 12 and a decrease in PGC numbers at later stages. The knockdown phenotype was rescued by intact DEADSouth mRNA, but not mutant mRNA encoding inactive DEADSouth helicase. Surprisingly, it was also rescued by mouse vasa homolog and Xenopus vasa-like gene 1 mRNAs that encode DDX4 RNA helicases. The rescue was dependent on the 3′ untranslated region (3′UTR) of DEADSouth mRNA, which was used for PGC-specific expression. The 3′UTR contributed to localization of the injected mRNA to the germ plasm, resulting in effective localization of DEADSouth protein. These results demonstrate that localization of DEADSouth helicase to the germ plasm is required for proper PGC development in Xenopus laevis.
Ciliated sensory hair cell formation and function require the F-BAR protein syndapin I and the WH2 domain-based actin nucleator Cobl
Authors: Schüler Susann , Hauptmann Judith , Perner Birgit , Kessels Michael M. , Englert Christoph , Qualmann Britta
Published: December 2012

During development, general body plan information must be translated into distinct morphologies of individual cells. Shaping cells is thought to involve cortical cytoskeletal components and Bin-Amphiphysin-Rvs167 (BAR) superfamily proteins. We therefore conducted comprehensive side-by-side loss-of-function studies of zebrafish orthologs of the F-BAR protein syndapin I and the actin nucleator Cobl. Zebrafish syndapin I associates with Cobl. The loss-of-function phenotypes of these proteins were remarkably similar and suggested a common function. Both cobl- and syndapin I-morphant fish showed severe swimming and balance-keeping defects, reflecting an impaired organization and function of the lateral line organ. Their lateral line organs lacked several neuromasts and showed an impaired functionality of the sensory hair cells within the neuromasts. Scanning electron microscopy revealed that sensory hair cells of both cobl- and syndapin I-morphant animals showed defects in the formation of both microtubule-dependent kinocilia and F-actin-rich stereocilia. Consistent with the kinocilia defects in sensory hair cells, body length was shortened and the development of body laterality, a process depending on motile cilia, was also impaired. Interestingly, Cobl and syndapin I both localized to the base of forming cilia. Rescue experiments demonstrated that proper formation of ciliated sensory hair cell rosettes relied on Cobl's syndapin I-binding Cobl homology domain, the actin-nucleating C-terminus of Cobl and the membrane curvature-inducing F-BAR domain of syndapin I. Our data thus suggest that the formation of distinct types of ciliary structures relies on membrane topology-modulating mechanisms that are based on F-BAR domain functions and on complex formation of syndapin I with the actin nucleator Cobl.
Get3 is a holdase chaperone and moves to deposition sites for aggregated proteins when membrane targeting is blocked
Authors: Powis Katie , Schrul Bianca , Tienson Heather , Gostimskaya Irina , Breker Michal , High Stephen , Schuldiner Maya , Jakob Ursula , Schwappach Blanche
Published: December 2012

The endomembrane system of yeast contains different tail-anchored proteins that are post-translationally targeted to membranes via their C-terminal transmembrane domain. This hydrophobic segment could be hazardous in the cytosol if membrane insertion fails, resulting in the need for energy-dependent chaperoning and the degradation of aggregated tail-anchored proteins. A cascade of GET proteins cooperates in a conserved pathway to accept newly synthesized tail-anchored proteins from ribosomes and guide them to a receptor at the endoplasmic reticulum, where membrane integration takes place. It is, however, unclear how the GET system reacts to conditions of energy depletion that might prevent membrane insertion and hence lead to the accumulation of hydrophobic proteins in the cytosol. Here we show that the ATPase Get3, which accommodates the hydrophobic tail anchor of clients, has a dual function: promoting tail-anchored protein insertion when glucose is abundant and serving as an ATP-independent holdase chaperone during energy depletion. Like the generic chaperones Hsp42, Ssa2, Sis1 and Hsp104, we found that Get3 moves reversibly to deposition sites for protein aggregates, hence supporting the sequestration of tail-anchored proteins under conditions that prevent tail-anchored protein insertion. Our findings support a ubiquitous role for the cytosolic GET complex as a triaging platform involved in cellular proteostasis.
Actin-regulated feedback loop based on Phactr4, PP1 and cofilin maintains the actin monomer pool
Authors: Huet Guillaume , Rajakylä Eeva Kaisa , Viita Tiina , Skarp Kari-Pekka , Crivaro Marko , Dopie Joseph , Vartiainen Maria K.
Published: December 2012

Phactr proteins bind actin and protein phosphatase 1 (PP1), and are involved in processes ranging from angiogenesis to cell cycle regulation. Phactrs share a highly conserved RPEL domain with the myocardin-related transcription factor (MRTF) family, where actin binding to this domain regulates both the nuclear localization and the activity of these transcription coactivators. We show here that in contrast to MRTF-A, the RPEL domain is dispensable for the subcellular localization of Phactr4. Instead, we find the domain facilitating competitive binding of monomeric actin and PP1 to Phactr4. Binding of actin to Phactr4 influences the activity of PP1 and the phosphorylation status of one of its downstream targets, cofilin. Consequently, at low actin monomer levels, Phactr4 guides PP1 to dephosphorylate cofilin. This active form of cofilin is then able to sever and depolymerize actin filaments and thus restore the actin monomer pool. Accordingly, our data discloses the central role of Phactr4 in a feedback loop, where actin monomers regulate their own number via the activation of a key regulator of actin dynamics. Depending on the protein context, the RPEL domain can thus elicit mechanistically different responses to maintain the cellular actin balance.
In tight junctions, claudins regulate the interactions between occludin, tricellulin and marvelD3, which, inversely, modulate claudin oligomerization
Authors: Cording Jimmi , Berg Johanna , Käding Nadja , Bellmann Christian , Tscheik Christian , Westphal Julie K. , Milatz Susanne , Günzel Dorothee , Wolburg Hartwig , Piontek Jörg , Huber Otmar , Blasig Ingolf Ernst
Published: December 2012

Tight junctions seal the paracellular cleft of epithelia and endothelia, form vital barriers between tissue compartments and consist of tight-junction-associated marvel proteins (TAMPs) and claudins. The function of TAMPs and the interaction with claudins are not understood. We therefore investigated the binding between the TAMPs occludin, tricellulin, and marvelD3 and their interaction with claudins in living tight-junction-free human embryonic kidney-293 cells. In contrast to claudins and occludin, tricellulin and marvelD3 showed no enrichment at cell–cell contacts indicating lack of homophilic trans-interaction between two opposing cell membranes. However, occludin, marvelD3 and tricellulin exhibited homophilic cis-interactions, along one plasma membrane, as measured by fluorescence resonance energy transfer. MarvelD3 also cis-interacted with occludin and tricellulin heterophilically. Classic claudins, such as claudin-1 to -5 may show cis-oligomerization with TAMPs, whereas the non-classic claudin-11 did not. Claudin-1 and -5 improved enrichment of occludin and tricellulin at cell–cell contacts. The low mobile claudin-1 reduced the membrane mobility of the highly mobile occludin and tricellulin, as studied by fluorescence recovery after photobleaching. Co-transfection of claudin-1 with TAMPs led to changes of the tight junction strand network of this claudin to a more physiological morphology, depicted by freeze-fracture electron microscopy. The results demonstrate multilateral interactions between the tight junction proteins, in which claudins determine the function of TAMPs and vice versa, and provide deeper insights into the tight junction assembly.
Plexin B1 inhibits MET through direct association and regulates Shp2 expression in melanocytes
Authors: Soong Joanne , Scott Glynis
Published: December 2012

Plexin B1, the receptor for Semaphorin 4D (Sema4D), is expressed by melanocytes in the skin. We recently showed that Sema4D suppresses activation of the hepatocyte growth factor receptor, MET, in melanocytes, and that knockdown of Plexin B1 results in activation of MET. MET signaling mediates proliferation, survival and migration in melanocytes, and its activation is associated with transformation of melanocytes to melanoma. In this report we investigated the mechanism by which Plexin B1 inhibits MET activation. Our results show that Plexin B1 and MET exist as an oligomeric receptor-receptor complex in melanocytes, and that receptor association is increased by Sema4D. MET and Plexin B1 receptor complexes were identified along the cell body of melanocytes, and Sema4D increased receptor association on dendrites, suggesting that Sema4D regulates MET-dependent processes at precise locations on the melanocyte. Despite activation of MET, Plexin B1 knockdowns proliferated slowly and showed increased apoptosis compared with controls. Shp2, a non-receptor protein tyrosine phosphatase, translates growth and survival signals from MET and other receptor tyrosine kinases. Plexin B1 knockdowns had markedly lower levels of Shp2 compared with controls, and Sema4D upregulated Shp2 expression at the protein and message level in normal melanocytes. Functional studies showed that blockade of Shp2 activity abrogated MET-dependent activation of Erk1/Erk2 and Akt in melanocytes. These results suggest a complex role for Sema4D and Plexin B1 in orchestrating signaling from the MET receptor in melanocytes. Because Shp2 is a downstream adaptor protein for multiple receptors, Sema4D may control the effects of several growth factors on melanocytes through regulation of Shp2.
Role of Ser129 phosphorylation of α-synuclein in melanoma cells
Authors: Lee Byung Rho , Matsuo Yasuhiro , Cashikar Anil G. , Kamitani Tetsu
Published: December 2012

α-Synuclein, a protein central to Parkinson's disease, is frequently expressed in melanoma tissues, but not in non-melanocytic cutaneous carcinoma and normal skin. Thus, α-synuclein is not only related to Parkinson's disease, but also to melanoma. Recently, epidemiologists reported co-occurrence of melanoma and Parkinson's disease in patients, suggesting that these diseases could share common pathogenetic components and that α-synuclein might be one of these. In Parkinson's disease, phosphorylation of α-synuclein at Ser129 plays an important role in the pathobiology. However, its role in melanoma is not known. Here, we show the biological relevance of Ser129 phosphorylation in human melanoma cells. First, we have identified an antibody that reacts with Ser129-unphosphorylated α-synuclein but not with Ser129-phosphorylated α-synuclein. Using this and other antibodies to α-synuclein, we investigated the role of Ser129 phosphorylation in human melanoma SK-MEL28 and SK-MEL5 cells. Our immunofluorescence microscopy showed that the Ser129-phosphorylated form, but not the Ser129-unphosphorylated form, of α-synuclein localizes to dot-like structures at the cell surface and the extracellular space. Furthermore, immuno-electron microscopy showed that the melanoma cells release microvesicles in which Ser129-phosphorylated α-synuclein localizes to the vesicular membrane. Taken together, our studies suggest that the phosphorylation of Ser129 leads to the cell surface translocation of α-synuclein along the microtubule network and its subsequent vesicular release in melanoma cells.
Novel Strategies to Test Biological Hypotheses in Early Drug Development for Advanced Prostate Cancer
Authors: Ferraldeschi Roberta , Attard Gerhardt , de Bono Johann S
Published: December 2012

BACKGROUND

Major advances in our understanding of the underlying biology of prostate cancer have helped to herald a new era in the treatment of castration-resistant prostate cancer (CRPC), with 5 new agents having shown a survival advantage in the last 3 years and an impressive number of promising novel agents now entering the clinic.

CONTENT

We discuss the challenges facing drug development for CRPC and strategies to meet these challenges, with a focus not only on the development of predictive and intermediate endpoint biomarkers, but also on novel hypothesis-testing, biomarker-driven clinical trial designs.

With several promising agents now entering the clinic, there is increasing pressure to rethink drug development for CRPC to ensure that novel agents are appropriately evaluated and that patients and resources are appropriately allocated. We envision that biomarker-driven, reiterative clinical trials will have a major impact on CRPC treatment through the testing of robust scientific hypotheses with rationally designed drugs and drug combinations administered to selected patients.
The Tropical Agenda
Authors: Harding Sandra
Published: December 2012

The Torrid Zone, more casually referred to as the tropics, has been discriminated against since Aristotle divided the world into three zones. The tropics have been considered too hot for civilised habitation, a place of great horrors, and a dangerous place of pestilence. Consequently, others have chosen to explore the Temperate and Frigid zones. However, the tropics has become an increasingly critical global zone. With a huge, and rapidly growing, population it is facing some of the most formidable issues in history, including the impact of climate change and environmental degradation, poor health and educational outcomes, extreme poverty, and political and economic instability. This article advocates for the tropics to be recognised as a major expanding geo-political region that needs to be comprehensively understood by psychology and other disciplines through research and investigation.
Transcolonial Influences on Everyday American Imperialism: The Politics of Chinese Domestic Servants in the Philippines
Authors: Martínez Julia , Lowrie Claire
Published: December 2012

From the first years of the American occupation of the Philippines, the American colonial elite ran their households with the help of Chinese servants. The preference of government officials, including Governor William Howard Taft himself, for Chinese domestic labor was in flagrant disregard for the policy of Chinese exclusion as well as the principle of “benevolent assimilation,” according to which the Americans claimed to be “uplifting” the Filipino people by providing them with the opportunity to experience the dignity of labor. In opting for Chinese rather than Filipino domestic labor, elite Americans were replicating the traditions of the “Old World” colonizers, particularly the British in Asia.
An Inmate's Response to James Mace Ward's “Legitimate Collaboration”
Authors: Hecht Irene W. D.
Published: December 2012

James Mace Ward framed his argument as a case of “legitimate collaboration, based on administrative documents and individual memoirs. As a survivor of the Santo Tomás Internment Camp (January 1942–February 3, 1945), Irene Hecht suggests that the concept of collaboration distracts from an understanding of the camp's realities. She distinguishes four stages in the evolution of the internee experience: denial; “lemonade from lemons”; making do; and struggle for survival. Survival was always the issue, but how it was defined and framed changed over time. Hecht suggests that the internees' experience should be seen as a history of a community's survival in which their sociopolitical heritage was a crucial factor in ensuring the survival of most of the inmates.
Collaboration and Legitimacy: A Reply to Irene Hecht
Authors: Ward James Mace
Published: December 2012

James Mace Ward responds to Dr. Irene Hecht's criticism of his 2008 Pacific Historical Review article “Legitimate Collaboration: The Administration of Santo Tomás Interment Camp and Its Histories, 1942–2003.” Although Ward rejects Hecht's claim that “collaboration” is an inappropriate way to understand the Santo Tomás internment, he praises her reply as a valuable memoir by a former child internee. Ward also elucidates the evolution and purpose of his category of “legitimate collaboration.”
Long-term clinical data and molecular defects in the STAR gene in five Greek patients
Authors: Sertedaki Amalia , Dracopoulou Maria , Voutetakis Antonis , Stefanaki Kalliopi , Rontogianni Dimitra , Magiakou Alexandra-Maria , Kanaka-Gantenbein Christina , Chrousos George , Dacou-Voutetakis Catherine
Published: December 2012

Context

Steroidogenic acute regulatory (STAR) gene mutations lead to adrenal and gonadal failure. Interesting, though as yet unexplained, features are the formation of ovarian cysts and the potential presence of CNS findings.

Objective

To report biochemical, genetic, and long-term clinical data in five Greek patients from four different families withSTARgene defects (three 46,XX and two 46,XY).

Methods and results

All patients presented in early infancy with adrenal insufficiency. TheSTARgene mutation c.834del11bp, detected in three of our patients, completely alters the carboxyl end of the STAR protein and has not thus far been described in other population groups. These three patients belong to three separate families, possibly genetically related, as they live in different villages located in a small region of a Greek island. However, their interrelationship has not been proven. A second mutation, p.W250X, detected in our fourth family, was previously described only in two Serbian patients. Ovarian cysts were detected ultrasonographically in our 46,XX patients and seemed to respond to a low dose of a contraceptive. The histology of an excised ovarian cyst was diagnosed as a corpus luteum (CL) cyst. In two out of the four patients who had undergone brain magnetic resonance imaging, asymptomatic Chiari-1 malformation was observed.

Conclusions

The occurrence ofSTARgene mutation c.834del11bp in three families living in a restricted geographic region could indicate either a founder effect or simply reflect a spread of this defect in a highly related population. The ovarian histological findings suggest that ovarian cysts detected ultrasonographically in 46,XX individuals withSTARgene defects may be CL cysts. The Chiari-1 malformation in two of our patients may be part of theSTARgene mutation phenotype. Nevertheless, more data are needed to confirm or disprove the existence of specific CNS pathology in patients withSTARgene mutations.
Structure characterization of organic-inorganic nanocomposites formed by the sol-gel polycondensation
Authors: Matìjka Libor
Published: December 2012

The organic-inorganic (O-I) hybrid networks were prepared from well-defined O-I precursors (a) alkoxysilane-endcapped oligomers (ASO) and (b) epoxy-functional silsesquioxane (SSQO) clusters (EC). ASO precursors were crosslinked by sol-gel polycondensation and EC by the reaction of the epoxy groups with oligomeric diamine Jeffamine D2000. Formation, structure and mechanical properties of the networks were followed by SEC, NMR, SAXS and DMA. The O-I block copolymer network is composed of SSQO domains forming network junctions linked by an oligomer chain. Structure of the SSQO crosslink “points” ranges from compact polyhedral cages to large loose SSQO clusters in dependence on the precursor type and catalysis of the sol-gel process. Interphase interaction and mechanical properties of the O-I networks are discussed.
Soluble, High Molecular Weight Polysilsesquioxanes with Carboxylate Functionalities
Authors: Rahimian Kamyar , Loy Douglas A. , Wheeler David R.
Published: December 2012

High molecular weight polysilsesquioxanes with carboxylate functionalities were prepared by sol-gel polymerization of organotrialkoxysilanes bearing tert-butyl ester groups. Trialkoxysilyl-containing monomers of the type (RO)3Si(CH2)3C(O)OtBu (R = Me, Et) were prepared by hydrosilation of the corresponding vinylic tert-butyl esters CH3CHCH2C(O)OtBu. Acid- or base-catalyzed polymerization of the monomers leads to very high molecular weight polymers with relatively narrow polydispersities. The polymerization results in complete condensation of the alkoxy groups while the tert-butyl ester functionality remains fully intact. Partial or full deprotection of the tert-butyl group can easily be achieved to yield the corresponding carboxylic acid polymers. The ester and carboxylic acid functionalities of these new materials allow for their potential use in a variety of applications such as scavenging of heavy metals.
Novel Materials Based on Organic-Tungsten Oxide Hybrid Systems
Authors: Ingham Bridget , Chong Shen V. , Tallon Jeff L.
Published: December 2012

The physical and electronic properties of tungsten oxide and some related hybrid materials have been examined via various spectroscopic techniques and the results complemented by ab initio computation. Hybrid materials based on intercalated straight-chain σ,ω-diaminoalkanes in between sheets of corner-shared tungsten-oxide octahedra exhibit from XRD a linear expansion in the interlayer spacing with increasing number of carbon atoms in the amines. UV-visible diffuse reflectance spectra of several hybrid powders indicate a dominant absorption edge centred at 4.0 eV, with no apparent trend among the different samples as the alkyl chain length changes. This is higher than that of tungsten trioxide powder, which has an absorption edge centred at 2.8 eV. Ab initio calculations show that these experimental values may relate to the indirect band-gap energies of the respective compounds rather than the optical band gap. This was confirmed from the absorption coefficient results of WO3 thin films which yield a strong edge at 4.0 eV. Similar measurements of hybrid films with 1,12-diaminododecane as the organic spacer showed absorption throughout the visible range, with weak features at 4.2 and 4.9 eV.
Methane/water Adsorption Properties of Synthetic Imogolite Nanotubes
Authors: Ohashi Fumihiko , Tomura Shinji , Wada Shin-Ichiro
Published: December 2012

Aluminosilicate nanotubes (imogolite) have been synthesized from highly concentrated inorganic solutions by hydrothermal treatment. These can be converted to microporous nanofibers with a pore radius in the range of 0.3-0.6 nm referring to the results from the nitrogen adsorption isotherm. The water vapor adsorption isotherms indicated that the natural imogolite plotted a proportional isothermal curve where the amount of adsorbed water increased in proportion to P/P0: the maximum amount of adsorbed water was ca. 60 wt%. The synthetic imogolite showed a rapid increase at 0.9-0.95 range of P/P0 and achieved a maximum of ca. 80 wt%, with a better methane storage property than that of the usual compressed natural gas storage. In order to obtain a high ratio of water adsorption and a large methane storage capacity, it is necessary to control the micro/meso porous structure and the hydrophilic/hydrophobic surface affinity. It is expected that the synthetic imogolite might become a multipurpose adsorbent.
Reverse Micelle Synthesis of Zirconia Powders: The Use of Hydrogen Peroxide as Washing Solvent
Authors: Singh Harpreet , Graeve Olivia A.
Published: December 2012

Yttria-stabilized zirconia nanopowders were synthesized using AOT/isooctane reverse micelles. XRD results showed that the powders were tetragonal with crystallite sizes ranging between approximately 1-50 nm depending on the thermal treatment given to the powders. BET surface area analysis of the powders gave a specific surface area of 230 m2/g for the assynthesized powders and 19.3 m2/g for the powders treated at 1000°C. This results in equivalent powder particle diameters of 4 nm and 52 nm, respectively. Washing of the powders is a very significant step for successful post-processing of powders obtained by AOT/isooctane reverse micelles. The use of ethanol and dry ether did not remove AOT, as determined from EDS measurements. Subsequent experiments showed that a novel solvent (hydrogen peroxide) was effective in removing AOT from the powders. The reason for the effectiveness of the new solvent is its capacity to decompose the AOT into weak acids, which are easily washed away with deionized water.