bluuebunny/crossref_metadata_2025_split huggingface dataset:
Distinct expression and activity profiles of largemouth bass (Micropterus salmoides) estrogen receptors in response to estradiol and nonylphenol
Authors: Sabo-Attwood Tara , Blum Jason L , Kroll Kevin J , Patel Vishal , Birkholz Detlef , Szabo Nancy J , Fisher Suzanne Z , McKenna Robert , Campbell-Thompson Martha , Denslow Nancy D 
Published: October 2007

AbstractThe estrogen receptor (ER) signaling cascade is a vulnerable target of exposure to environmental xenoestrogens, like nonylphenol (NP), which are causally associated with impaired health status. However, the impact of xenoestrogens on the individual receptor isotypes (α, βa, and βb) is not well understood. The goal of these studies was to determine the impact of NP on largemouth bass (Micropterus salmoides) ER isotype expression and activity. Here, we show that hepatic expression levels of three receptors are not equivalent in male largemouth bass exposed to NP by injection. Transcript levels of the ERα subtype were predominantly induced in concert with vitellogenin similarly to fish exposed to 17β-estradiol (E2) as measured by quantitative real-time PCR. NP also induced circulating plasma levels of estrogen, which may contribute to overall activation of the ERs. To measure the activation of each receptor isotype by E2 and NP, we employed reporter assays using an estrogen response element (ERE)–luciferase construct. Results from these studies show that ERα had the greatest activity following exposure to E2 and NP. This activity was inhibited by the antagonists ICI 182 780 and ZM 189 154. Furthermore, both βb and βa subtypes depressed ERα activation, suggesting that the cellular composition of receptor isotypes may contribute to the overall actions of estrogen and estrogenic contaminants via the receptors. Results from these studies collectively reveal the differential response of fish ER isotypes in response to xenoestrogens.
Role of specificity protein transcription factors in estrogen-induced gene expression in MCF-7 breast cancer cells
Authors: Khan Shaheen , Wu Fei , Liu Shengxi , Wu Qian , Safe Stephen 
Published: October 2007

AbstractDeletion analysis of several 17β-estradiol (E2)-responsive genes have identified GC-rich sites that are associated with hormone-induced transactivation in MCF-7 breast cancer cells. However, the role of individual specificity proteins (Sps) in mediating hormone-induced gene expression has not been unequivocally determined. In transient transfection studies using E2-responsive GC-rich promoters from the E2F1, carbamoylphosphate synthetase/aspartate transcarbamylase/dihydroorotase (CAD), and retinoic acid receptor α (RARα) genes, RNA interference using small inhibitory RNAs for Sp1 (iSp1), Sp3 (iSp3), and Sp4 (iSp4) decreased both basal and E2-induced transactivation. The contributions of individual Sp proteins to basal and E2-induced activity were promoter dependent. iSp1, iSp3, and iSp4 also significantly inhibited hormonal induction of E2F1, CAD, and RARα mRNA levels; however, the enhanced inhibitory effects of the latter two small inhibitory RNAs suggest that Sp3 and Sp4 play a major role in estrogen receptor α/Sp-mediated gene expression in MCF-7 cells.
Crosstalk of CREB and Fos/Jun on a single cis-element: transcriptional repression of the steroidogenic acute regulatory protein gene
Authors: Manna Pulak R , Stocco Douglas M 
Published: October 2007

AbstractTranscriptional regulation of the steroidogenic acute regulatory (StAR) protein gene by cAMP-dependent mechanisms occurs in the absence of a consensus cAMP-response element (CRE; TGACGTCA) and is mediated by several sequence-specific transcription factors. We previously identified three CRE-like sites (within the −151/−1 bp cAMP-responsive region of the mouse StAR gene), of which the CRE2 site overlaps with an activator protein-1 (AP-1) motif (TGACTGA, designated as CRE2/AP-1) that can bind both CRE and AP-1 DNA-binding proteins. The present studies were aimed at exploring the functional crosstalk between CREB (CRE-binding protein) and cFos/cJun (AP-1 family members) on the CRE2/AP-1 element and its role in regulating transcription of the StAR gene. Using MA-10 mouse Leydig tumor cells, we demonstrate that the CRE and AP-1 families of proteins interact with the CRE2/AP-1 sequence. CREB, cFos, and cJun proteins were found to bind to the CRE2/AP-1 motif but not the CRE1 and CRE3 sites. Treatment with the cAMP analog (Bu)2cAMP augmented phosphorylation of CREB (Ser133), cFos (Thr325), and cJun (ser73). Chromatin immunoprecipitation studies revealed that the induction of CREB, cFos, and cJun by (Bu)2cAMP was correlated with protein–DNA interactions and recruitment of the coactivator CREB-binding protein (CBP) to the StAR promoter. EMSA studies employing CREB and cFos/cJun proteins demonstrated competition between these factors for binding to the CRE2/AP-1 motif. Transfection of cells containing the −151/−1 StAR reporter with CREB and cFos/cJun resulted in trans-repression of the StAR gene, an event tightly associated with CBP, demonstrating that both CREB and Fos/Jun compete with each other for binding with limited amounts of intracellular CBP. Overexpression of adenovirus E1A, which binds and inactivates CBP, markedly suppressed StAR gene expression. Ectopic expression of CBP eliminated the repression of the StAR gene by E1A and potentiated the activity of CREB and cFos/cJun on StAR promoter responsiveness. These findings identify molecular events involved in crosstalk between CREB and cFos/cJun, which confer both gain and loss of function on a single cis-element in fine-tuning of the regulatory events involved in transcription of the StAR gene.
20β-hydroxysteroid dehydrogenase and CYP19A1 are differentially expressed during maturation in Atlantic cod (Gadus morhua)
Authors: Mittelholzer C , Andersson E , Consten D , Hirai T , Nagahama Y , Norberg B 
Published: October 2007

AbstractIn order to better quantify the molecular mechanisms regulating final oocyte maturation and spawning, complete coding sequences with partially or fully untranslated regions for the steroidogenic enzymes, cytochrome P450 aromatase and 20β-hydroxysteroid dehydrogenase, were cloned from ovaries of Atlantic cod (Gadus morhua). The nucleotide and amino acid sequences showed high homologies with the corresponding sequences of other fish species, and conserved features important for functionality were identified in both predicted proteins. The sequences of the corresponding genomic loci were also determined, allowing the design of mRNA-specific quantitative PCR assays. As a reference gene for the real-time RT-PCR assays, eukaryotic elongation factor 1α was chosen, and the mRNA as well as the genomic sequence was determined. In addition, a real-time quantitative PCR assay for the 18S rRNA was adapted to be used in cod. Analysis of immature and maturing female cod from July to January respectively showed that the enzyme genes showed the expected quantitative changes associated with physiological regulation. However, mRNA for eukaryotic elongation factor 1α, and to a lesser extent even 18S rRNA, showed variable expression in these samples as well. To find accurate standards for real-time PCR in such a dynamic organ as the cod ovary is not an easy task, and several possible solutions are discussed.
Expression of NG,NG-Dimethylarginine Dimethylaminohydrolase and Protein Arginine N-Methyltransferase Isoforms in Diabetic Rat Kidney
Authors: Onozato Maristela L. , Tojo Akihiro , Leiper James , Fujita Toshiro , Palm Fredrik , Wilcox Christopher S. 
Published: October 2007

OBJECTIVE—The nitric oxide (NO) synthase inhibitor asymmetric dimethylarginine (ADMA) is generated by protein arginine N-methyltransferase (PRMT)-1 and is metabolized by NG,NG-dimethylarginine dimethylaminohydrolase (DDAH). We tested the hypothesis that increased serum ADMA (SADMA) in the streptozotocin (STZ)-induced diabetic rat model of diabetes is mediated by an angiotensin receptor blocker–sensitive change in DDAH or PRMT expression.
RESEARCH DESIGN AND METHODS—Data were compared from four groups of rats: sham-injected controls, untreated STZ-induced diabetic rats at 4 weeks, STZ-induced diabetic rats administered the angiotensin II (Ang II) receptor blocker telmisartan for 2 weeks, and control rats administered telmisartan for 2 weeks.
RESULTS—Immunostaining and Western blotting of microdissected nephron segments localized DDAH I in the proximal tubules and DDAH II in the glomeruli, afferent arterioles, macula densa, and distal nephron. Renal Ang II and SADMA increased with diabetes but were normalized by 2 weeks of telmisartan. DDAH I expression was decreased in diabetic kidneys, while DDAH II expression was increased. These changes were reversed by telmisartan, which also reduced expression of PRMT-1 and -5. Telmisartan increased expressions of DDAH I but decreased DDAH II in Ang II-stimulated kidney slices ex vivo.
CONCLUSIONS—Renal Ang II and SADMA are increased in insulinopenic diabetes. They are normalized by an Ang II receptor blocker, which increases the renal expression of DDAH I, decreases PRMT-1, and increases renal NO metabolites.
Stromal Cell–Derived Factor-1/CXCL12 Stimulates Chemorepulsion of NOD/LtJ T-Cell Adhesion to Islet Microvascular Endothelium
Authors: Sharp Christopher D. , Huang Meng , Glawe John , Patrick D. Ross , Pardue Sible , Barlow Shayne C. , Kevil Christopher G. 
Published: October 2007

OBJECTIVE—Diabetogenic T-cell recruitment into pancreatic islets faciltates β-cell destruction during autoimmune diabetes, yet specific mechanisms governing this process are poorly understood. The chemokine stromal cell–derived factor-1 (SDF-1) controls T-cell recruitment, and genetic polymorphisms of SDF-1 are associated with early development of type 1 diabetes.
RESEARCH DESIGN AND METHODS—Here, we examined the role of SDF-1 regulation of diabetogenic T-cell adhesion to islet microvascular endothelium. Islet microvascular endothelial cell monolayers were activated with tumor necrosis factor-α (TNF-α), subsequently coated with varying concentrations of SDF-1 (1–100 ng/ml), and assayed for T-cell/endothelial cell interactions under physiological flow conditions.
RESULTS—TNF-α significantly increased NOD/LtJ T-cell adhesion, which was completely blocked by SDF-1 in a dose-dependent manner, revealing a novel chemorepulsive effect. Conversely, SDF-1 enhanced C57BL/6J T-cell adhesion to TNF-α–activated islet endothelium, demonstrating that SDF-1 augments normal T-cell adhesion. SDF-1 chemorepulsion of NOD/LtJ T-cell adhesion was completely reversed by blocking Giα-protein–coupled receptor activity with pertussis toxin. CXCR4 protein expression was significantly decreased in NOD/LtJ T-cells, and inhibition of CXCR4 activity significantly reversed SDF-1 chemorepulsive effects. Interestingly, SDF-1 treatment significantly abolished T-cell resistance to shear-mediated detachment without altering adhesion molecule expression, thus demonstrating decreased integrin affinity and avidity.
CONCLUSIONS—In this study, we have identified a previously unknown novel function of SDF-1 in negatively regulating NOD/LtJ diabetogenic T-cell adhesion, which may be important in regulating diabetogenic T-cell recruitment into islets.
Purification and Concentration of DNA from Aqueous Solutions
Authors: Moore David , Dowhan Dennis 
Published: October 2007

AbstractThis unit presents basic procedures for manipulating solutions of single‐ or double‐stranded DNA through purification and concentration steps. These techniques are useful when proteins or solute molecules need to be removed from aqueous solutions, or when DNA solutions need to be concentrated. The Basic Protocol, using phenol extraction and ethanol (or isopropanol) precipitation, is appropriate for purification of DNA from small volumes (<0.4 ml) at concentrations lower than 1 mg/ml. Three support protocols outline methods to buffer the phenol used in extractions, concentrate DNA using butanol, and extract residual organic solvents with ether, respectively. An alternative to these methods is nucleic acid purification using glass beads, and this technique is also presented. These protocols may also be used for purifying RNA. The final two alternate protocols are used for concentrating RNA and extracting and precipitating DNA from larger volumes and from dilute solutions, and for removing low‐molecular‐weight oligonucleotides and triphosphates. Curr. Protoc. Pharmacol. 38:A.3C.1‐A.3C.10. © 2007 by John Wiley & Sons, Inc.
Neural Differentiation of Human ES Cells
Authors: A. Cohen Malkiel , Itsykson Pavey , E. Reubinoff Benjamin 
Published: October 2007

AbstractHuman embryonic stem cells (hESCs) may be converted into highly enriched cultures of neural precursors under defined culture conditions. The neural precursors can proliferate in culture for prolonged periods of time, and can differentiate in vitro into mature neurons, astrocytes, and oligodendrocytes. The neurons are functional and have normal electrophysiological properties. After transplantation to the developing rodent brain, the neural precursors migrate extensively into the host brain parenchyma, respond to host brain signals, and differentiate in a region‐specific manner to progeny of the three neural lineages. The establishment of neuroectodermal precursors from hESCs allows the study of human neurogenesis in vitro and is an aid in drug discovery. In addition, the neural precursors may potentially serve as a platform for the development of specific functional neural cells for transplantation and gene therapy of neurological disorders. In this unit, we introduce methods for the derivation, propagation and characterization of hESC‐derived neural precursors. Curr. Protoc. Cell Biol. 36:23.7.1‐23.7.20. © 2007 by John Wiley & Sons, Inc.
Cotrimerizations of Acetylenic Compounds
Authors: Agenet Nicolas , Buisine Olivier , Slowinski Franck , Gandon Vincent , Aubert Corinne , Malacria Max 
Published: October 2007

Abstract
The cyclotrimerization of acetylenic compounds is a useful method for the construction of three new bonds in a one‐step process. Although symmetry‐allowed, there is a paucity of examples of purely thermal [2+2+2] cycloadditions. The first example reported was in 1866, which was the cyclization of acetylene to benzene. High temperatures are required for this reaction and a mixture of products is formed. In 1948, Reppe discovered the first transition‐metal catalyzed version of this reaction in which nickel was used and substituted benzenes were formed. Since then catalysts based on transition metals, lanthanides, actinide, and aluminum have been developed for the cycloaddition of substituted alkynes to benzene derivatives. Many compounds can take part in the cyclization reactions to give four‐, five‐,six, or eight membered rings. Many of these reactions have found many applications in organic synthesis
This chapter is devoted to early to late transition metal‐mediated cotrimerization of acetylenic compounds directed towards organic synthesis. It addresses the scope and generality of the reaction, as well as the current state of the art, with regard to region‐and stereoselectivities. In the context of selectivity, a mechanistic overview is provided. Inter‐and intramolecular versions of the cyclizations are presented with an emphasis on applications in synthesis. The literature up to mid‐2004 is covered.
Glycosylation on Polymer Supports
Authors: Bufali Simone , Seeberger Peter H. 
Published: October 2007

Abstract
Oligosaccharide synthesis has gained major attention in the last two decades particularly in the total synthesis of biologically interesting molecules. Carbohydrates contain many stereocenters and are often branched oligomers. The preparation of these complex methods is time consuming and mostly carried out by specialized laboratories. The synthesis of oligosaccharides is challenging because every glycosylation creates a new stereogenic center. Each carbohydrate unit has up to four sites for chain elongation, which exhibit similar reactivity. The strategic choice of protection for the hydroxyl and amino groups is essential
The use of polymeric support can simplify the synthesis. Glycosylation efficiency can be increased using one coupling partner (either the glycoside nucleophile or glycoslyating agent) or other reagent in excess. Use of polymeric supports results in shortened process times since intermediate purification steps are not required. This chapter deals with the choice of carbohydrate monomers or dimers including the protecting groups and an anomeric leaving group, the choice of polymer support, and the selection of a proper linker resistant to all relevant reaction conditions. The choice of carbohydrate building blocks requires an appropriate protecting group strategy. It is important to consider whether the carbohydrate is connected to the support via the anomeric position or another hydroxyl group.
Sickle cell disease and pulmonary hypertension in Africa: A global perspective and review of epidemiology, pathophysiology, and management
Authors: Aliyu Zakari Y. , Kato Gregory J. , Taylor James , Babadoko Aliyu , Mamman Aisha I. , Gordeuk Victor R. , Gladwin Mark T. 
Published: October 2007

AbstractSecondary pulmonary hypertension (PAH) has been shown to have a prevalence of 30% in patients with sickle cell disease (SCD) with mortality rates of 40% at 40 months after diagnosis in the United States. The burden of SCD is highest in sub‐Saharan Africa, especially in Nigeria (West Africa), where approximately 6 million people are afflicted. The true global incidence, prevalence, and burden of SCD and its associated end organ complications however remain unknown. Chronic hemolysis represents a prominent mechanistic pathway in the pathogenesis of SCD‐associated pulmonary hypertension via a nitric oxide (NO) scavenging and abrogation of NO salutatory effects on vascular function, including smooth muscle relaxation, downregulation of endothelial adhesion molecules and inhibition of platelet activation. Many known infectious risk factors for PAH are also hyperendemic in Africa, including Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome (HIV/AIDS), chronic hepatitis B and C, and possibly malaria. Interactions between these infectious complications and SCD‐related hemolysis could yield an even higher prevalence of pulmonary hypertension and compound the existing global health systems challenges in managing SCD. Indeed, our preliminary analysis of African immigrants currently in the United States suggests that pulmonary hypertension represents a significant complication of SCD in the African subcontinent. There is clearly a need to include Africa and other parts of the world with high SCD prevalence in future comprehensive studies on the epidemiology and treatment of end organ complications of an aging SCD population world‐wide. Am. J. Hematol., 2008. Published 2007 Wiley‐Liss, Inc.
Chromosome 5q subtelomeric deletion syndrome
Authors: Rauch Anita , Dörr Helmuth‐Günther 
Published: October 2007

AbstractThe pure 3.5 Mb subtelomeric deletion syndrome is very rare but causes a recognizable phenotype characterized by prenatal lymphedema with increased nuchal translucency, pronounced muscular hypotonia in infancy, borderline intelligence, postnatal short stature with delayed bone age due to growth hormone deficiency, and multiple minor anomalies including mildly bell‐shaped chest, minor congenital heart defects, and a distinct facial gestalt. Terminal deletions including the adjacent ∼2 Mb NSD1‐locus show a compound phenotype with overlap to Sotos syndrome. Larger terminal deletions including also chromosomal bands 5q35.1 and 5q35.2 cause a more severe phenotype with normal body length, significant congenital heart defect, microcephaly, profound developmental retardation or early death due to respiratory failure. Heart defects in the latter are explained by haploinsufficiency of the NKX2.5 gene at 5q35.1. The deletion breakpoint of the 3.5 Mb subtelomeric microdeletion maps to a low copy repeat which is identical to the distal copy of two highly similar regions flanking the recurrent interstitial NSD1 microdeletion. As meiotic mispairing between these low copy repeats seem to be much more likely than a terminal aberration, these neighborhood may prevent occurrence of the subtelomeric deletion syndrome, which could explain the rareness of the latter. © 2007 Wiley‐Liss, Inc.
DNA‐binding, antibacterial and spectral investigations of drug–Fe(II) complexes
Authors: Pansuriya Pramod B. , Patel Mohan N. 
Published: October 2007

AbstractThe antibiotic agent ciprofloxacin is well known for its drug design and coordinating ability towards metal ions. Iron(II) complexes of ciprofloxacin with various neutral bidentate ligands have been prepared. The structure of complexes has been investigated using spectral, physicochemical and elemental analyses. Antibacterial activity has been carried out using agar plate technique against Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Salmonella typhi, Escherichia coli and Serratia marcescens. The results show a significant increase in antibacterial activity compared with parental ligands, metal salt and standard drugs (ofloxacin, levofloxacin). The DNA binding and cleavage efficacy were determined using absorption titration and gel electrophoresis techniques, respectively. The DNA binding and cleavage efficacy were increased in complexes compared with parental ligands and metal salt. Copyright © 2007 John Wiley & Sons, Ltd.
Tragwerkssimulation von Verbundkonstruktionen aus Stahlbeton – Teil 1: Konzept und dreidimensionale Modellbildung
Authors: Lindig Volker 
Published: October 2007

AbstractBestimmte Konstruktionen und außergewöhnliche Beanspruchungen machen es mitunter auch bei der praktischen Tragwerksplanung erforderlich, realitätsnahe Simulationen durchzuführen, um z. B. die Entscheidungsfindung rechnerisch abzusichern sowie Detaillösungen zu beurteilen. Versuche sind auf einfache Modelltragwerke beschränkt. Eine Bewertung realer Tragwerke kann nur auf der Basis numerischer Simulationsverfahren erfolgen. Voraussetzung für solche dreidimensionalen Tragwerksanalysen unter dem Aspekt der Gebrauchs‐ und Grenztragfähigkeit sind geeignete Modelle zur Berücksichtigung der vielfältigen physikalisch nichtlinearen Einflüsse. Universelle FE‐Programme bieten hierfür die grundsätzliche Möglichkeit, eigene Materialmodelle in Abhängigkeit von der Zielstellung einzusetzen. Bei Verbundtragwerken ergibt sich zusätzlich das Problem der nachgiebigen Fuge, deren Einfluss auf das Gesamttragverhalten bedeutsam ist. Der Beitrag gliedert sich in 2 Teile: Teil 1 zeigt einen vorteilhaften Weg der Modellbildung auf. In Teil 2 werden spezifische Ansätze für die dreidimensionale Modellierung der Verbundfuge abgeleitet. Zudem folgt für eine generierte Verbundrahmenkonstruktion die Beschreibung von Detailuntersuchungen im Eckbereich. Es werden Empfehlungen für die Konstruktion gegeben.
Nachweis der Gebrauchstauglichkeit von Bauteilen aus Stahlbeton nach DIN 1045 und nach EC 2
Authors: Friedrich Richard 
Published: October 2007

AbstractDer Beitrag behandelt die häufig vorkommenden biegebeanspruchten Bauteile mit rechteckförmigem Querschnitt aus normalfestem Normalbeton C 20 bis C 50 mit einseitiger Bewehrung aus Betonstahl BSt 500. Bei der Berechnung der Durchbiegung w wird das Betonkriechen und ‐schwinden berücksichtigt, bei der Berechnung der Rißbreite wk und der Spannungen σc und σs das Kriechen allein.