bluuebunny/crossref_metadata_2025_split huggingface dataset:
Culture requirements of prostatic epithelial cell lines for acinar morphogenesis and lumen formation in vitro: Role of extracellular calcium
Authors: Tyson Darren R. , Inokuchi Junichi , Tsunoda Toshiyuki , Lau Alice , Ornstein David K. 
Published: August 2007

AbstractBACKGROUNDThree‐dimensional (3D) culture of benign prostatic epithelial cell lines can recapitulate acinar morphogenesis in vitro, but the broad applicability of this approach has not been described. The present studies examine the culture conditions important for prostatic acinar morphogenesis in vitro and the role of extracellular calcium in this process.METHODSWith optimized culture conditions, RWPE‐1, pRNS‐1‐1, PZ‐HPV‐7, PNT1A, BPH‐1, and PrEC were analyzed for their ability to undergo acinar morphogenesis in 3D culture and by immunoblotting. RWPE‐1 cells were further examined for the effects of calcium on morphology, E‐cadherin membrane localization and multicellular layering in 2D culture and for acinar morphogenesis, luminal apoptosis, and luminal filling in 3D.RESULTSCell lines grown in low‐calcium medium have the ability to form acinar structures with lumens, which correlates with E‐cadherin expression, but low calcium is not required for this process. Adding CaCl2 to the medium strongly inhibits lumen formation, luminal apoptosis and induces luminal filling, and luminal filling is blocked by an interfering antibody.CONCLUSIONSOptimized medium composition allows nearly all seeded RWPE‐1 cells to undergo acinar morphogenesis, forming consistent structures representative of normal adult prostate glands. Low‐calcium‐containing medium appears selective for cells capable of undergoing acinar morphogenesis in vitro, and branching and luminal space within the acini are strongly influenced by extracellular calcium levels, likely through the actions of E‐cadherin. These results provide important information about a relevant in vitro model with which to study prostate development and carcinogenesis and highlight the importance of extracellular calcium in regulating 3D morphology. Prostate 67: 1601–1613, 2007. © 2007 Wiley‐Liss, Inc.
Signal transducer and activator of transcription‐6 (STAT6) is a constitutively expressed survival factor in human prostate cancer
Authors: Das Susobhan , Roth Cherice P. , Wasson Lori M. , Vishwanatha Jamboor K. 
Published: August 2007

AbstractBACKGROUNDSignal transducer and activator of transcription (STAT)‐6 is a member of the STAT family of latent transcription factors. In this investigation, we examined STAT6 expression in clinical prostate cancer tissue specimen and determined its role in prostate cell proliferation and migration.METHODSSTAT6 expression in cell lines and tissues was analyzed by RT‐PCR, IHC and/or immunoblot analyses. Down‐regulation of STAT6 expression was achieved by STAT6 siRNA and its effect on cell migration and apoptosis was measured.RESULTSSTAT6 is highly expressed in the fibromuscular stroma of prostate cancer specimens. STAT6 is also expressed in the malignant epithelial layer and prostate intraepithelial neoplasia (PIN). STAT6 expression was significantly correlated with high histological grades of prostate cancer as well as with tumor size. Our data indicate deregulated STAT6 mRNA and protein expression in prostate cancer cells with high levels in the non‐cancerous HPV 18C‐1 and cancerous DU145 cell lines and low levels in PC3 and LNCaP cells. Phosphorylated STAT6 was expressed in all three cancer cell lines DU145, PC3, and LNCaP. Down‐regulation of STAT6 using siRNA leads to the induction of early apoptosis in DU145 cells and inhibits migration of these cells. Significant reduction in cell viability and transcriptional down‐regulation of the anti‐apoptotic protein Bcl‐XL was observed followed by STAT6 down‐regulation in DU145 cells. Interestingly STAT6 also regulates transcription of 15‐lipoxygenase‐1 gene in DU145 cells.CONCLUSIONSOur data suggest that STAT6 is a survival factor in prostate cancer and regulates the genetic transcriptional program that is responsible for prostate cancer progression. Prostate 67: 1550–1564, 2007. © 2007 Wiley‐Liss, Inc.
Epigallocatechin‐3‐Gallate suppresses early stage, but not late stage prostate cancer in TRAMP mice: Mechanisms of action
Authors: Harper Curt E. , Patel Brijesh B. , Wang Jun , Eltoum Isam A. , Lamartiniere Coral A. 
Published: August 2007

AbstractBACKGROUNDProstate cancer (PCa) is the second leading cause of cancer‐related death in men in the United States. Many men have implemented purported chemopreventive agents into their daily diet in an attempt to delay the early onset of a PCa. Green tea polyphenols, one such agent, has been shown to be chemopreventive in skin, breast, and prostate cancers. We hypothesized that Epigallocatechin‐3‐Gallate (EGCG), the major polyphenol found in green tea, will exert its chemopreventive effect in the prostate via regulation of sex steroid receptor, growth factor‐signaling, and inflammatory pathways.METHODSFive‐week‐old male TRAMP (Transgenic Adenocarcinoma Mouse Prostate) offspring were fed AIN‐76A diet and 0.06% EGCG in tap water. Animals were sacrificed at 28 weeks of age and the entire prostates were scored histopathologically. In addition, animals were sacrificed at 12 weeks of age and ventral (VP) and dorsolateral (DLP) prostates were removed for histopathological evaluation and immunoblot analyses or ELISA.RESULTSEGCG, inhibited early but not late stage PCa in the current study. In the VP, EGCG significantly reduced cell proliferation, induced apoptosis, and decreased androgen receptor (AR), insulin‐like growth factor‐1 (IGF‐1), IGF‐1 receptor (IGF‐1R), phospho‐extracellular signal‐regulated kinases 1 and 2 (phospho‐ERKs 1 and 2), cyclooxygenase‐2 (COX‐2), and inducible nitric oxide synthase (iNOS).CONCLUSIONSThe attenuation of the AR, the down‐regulation of potent growth factor IGF‐1, modulation of inflammation biomarkers, and decrease in the MAPK signaling may contribute to the reduction in cell proliferation and induction of apoptosis and hence provide a biochemical basis for EGCG suppressing PCa without toxicity. Prostate 67: 1576–1589, 2007. © 2007 Wiley‐Liss, Inc.
SELDI protein profiling of dunning R‐3327 derived cell lines: Identification of molecular markers of prostate cancer progression
Authors: Malik Gunjan , Rojahn Elizabeth , Ward Michael D. , Gretzer Mathew B. , Partin Alan W. , Semmes O. John , Veltri Robert W. 
Published: August 2007

AbstractBACKGROUNDWe recently demonstrated the protein expression profiling of Dunning rat tumor cell lines of varying metastatic potential (G (0%), AT‐1 (∼20%), and MLL (100%)) using SELDI‐TOF‐MS. As a parallel effort, we have been pursuing the identification of the protein(s) comprising the individual discriminatory “peaks” and evaluating their utility as potential biomarkers for prostate cancer progression.METHODSTo identify the observed SELDI‐TOF‐MS m/z (mass/charge) values with discriminatory expression between different sublines, we employed a combination of chemical pre‐fractionation, liquid chromatography, gel electrophoresis and tandem mass spectroscopy. Identified proteins were then verified by immuno‐assay and Western analysis.RESULTSA 17.5 K m/z SELDI‐TOF‐MS peak was found to retain discriminatory value in each of two separate study‐sets with an increased expression in the metastatic MLL line. Sequence identification and subsequent immunoassays verified that Histone H2B is the observed 17.5 K m/z SELDI peak. SELDI‐based immuno‐assay and Western Blotting revealed that Histone H2B is specifically over‐expressed in metastatic MLL lines.CONCLUSIONSSELDI‐TOF MS analysis of the Dunning prostate cancer cell lines confirmed the consistent overexpression of a 17.5 K m/z peak in metastatic MLL subline. The 17.5 kDa protein from MLL has been isolated and identified as Histone H2B. Prostate 67: 1565–1575, 2007. © 2007 Wiley‐Liss, Inc.
Crystal structure and putative function of small Toprim domain‐containing protein from Bacillus stearothermophilus
Authors: Řezáčová Pavlína , Borek Dominika , Moy Shiu F. , Joachimiak Andrzej , Otwinowski Zbyszek 
Published: August 2007

AbstractThe crystal structure of the Midwest Center for Structural Genomics target APC35832, a 14.7‐kDa cytosolic protein from Bacillus stearothermophilus, has been determined at 1.3 Å resolution by the single anomalous diffraction method from a mercury soaked crystal. The APC35832 protein is a representative of large group of bacterial and archeal proteins entirely consisting of the Toprim (topoisomerase‐primase) domain. This domain is found in the catalytic centers of many enzymes catalyzing phosphodiester bond formation or cleavage, but the function of small Toprim domain proteins remains unknown. Consistent with the sequence analysis, the APC35832 structure shows a conserved Toprim fold, with a central 4‐stranded parallel β‐sheet surrounded by four α‐helixes. Comparison of the APC35832 structure with its closest structural homolog, the catalytic core of bacteriophage T7 primase, revealed structural conservation of a metal binding site and isothermal titration calorimetry indicates that APC35832 binds Mg2+ with a sub‐millimolar dissociation constant (Kd). The APC35832–Mg2+ complex structure was determined at 1.65 Å and reveals the role of conserved acidic residues in Mg2+ ion coordination. The structural similarities to other Toprim domain containing proteins and potential function and substrates of APC35832 are discussed in this article. Proteins 2008. © 2007 Wiley‐Liss, Inc.
Cooperative symmetric to asymmetric conformational transition of the apo‐form of scavenger decapping enzyme revealed by simulations
Authors: Pentikäinen Ulla , Pentikäinen Olli T. , Mulholland Adrian J. 
Published: August 2007

AbstractDecapping is a central step in eukaryotic mRNA turnover and in gene expression regulation. The human scavenger decapping enzyme, DcpS, catalyses cap hydrolysis following mRNA degradation. DcpS is a dimeric enzyme, with two active sites. Crystal structures suggest that DcpS must undergo significant conformational changes upon ligand binding, but the mechanism of this transition is unknown. Here, we report two long timescale (20 ns) molecular dynamics simulations of the apo‐form of DcpS. The dimer is observed to undergo a strikingly cooperative motion, with one active site closing while the other opens. The amplitude of the conformational change is 6–21 Å and the apparent timescale is 4–13 ns. These findings indicate that the crystallographically observed symmetric conformation of apo‐form of DcpS is only a minor conformation in solution. The simulations also show that active sites are structurally connected via the domain‐swapped dimer structure of the N‐terminal domain, even in the absence of a bound ligand. These findings suggest a functional reason for the enzyme existing as a dimer, and may be widely relevant, also for other dimeric proteins. Proteins 2008. © 2007 Wiley‐Liss, Inc.
Quantifying the relationship of protein burying depth and sequence
Authors: Yuan Zheng , Wang Zhi‐Xin 
Published: August 2007

AbstractProtein burying depth (BD) is a structural descriptor that is exploited not only to find whether a residue is exposed or buried, but also to determine how deep a residue is buried. The widely used solvent accessible surface area is mainly focusing on the study of protein surface residues, while protein BD can provide more detailed information about the arrangement of buried residues, which may be used to study protein deep level structure and the formation of protein folding nucleus. In this work, we analyse the relationship of protein BD and sequences, and describe it by nonlinear functions estimated by support vector machines. We examine the functions by crossvalidation tests and find strong correlation between residue BD and local sequence environment. By further taking account the size of the molecule where a residue is located, we find that the correlation coefficient between predicted and observed depths improves from 0.60 to 0.65. Moreover, nearly half of the deepest 10% residues in a protein sequence can be correctly predicted. Our study suggests that a residue's burying extent is able to be predicted, to some degree, by itself and its local neighbouring residues. The methods used to estimate the sequence‐depth functions are expected to become more useful in the investigation of protein structures and folding mechanism. Proteins 2008. © 2007 Wiley‐Liss, Inc.
Synthesis of SiC nanofibers by microwave plasma assisted chemical vapour deposition in CH4/H2 gas mixture
Authors: Rizk S. , Assouar M. B. , Belmahi M. , Le Brizoual L. , Bougdira J. 
Published: August 2007

AbstractWe report in this study, the growth of silicon carbide nanofibers on silicon substrates covered by Fe thin film catalyst using microwave plasma assisted chemical vapour deposition. The silicon source is the substrate itself. The growth morphology, microstructure, and defects on SiC nanofibers are characterized by field emission scanning electron microscopy and transmission electron microscopy combined with electron energy‐dispersive X‐ray spectroscopy. These characterizations revealed that the resultant fibrous nanostructures, with a diameter of 25–65 nm, were assigned to β‐SiC. Selected area electron diffraction pattern shows a good crystallinity of the obtained nanofibers, and shows that the SiC nanofibers grow along (111) orientation. The formation of SiC nanofibers can be explained by the diffusion of Fe in the silicon substrate due to the high temperature during the process which is around 900 °C. The combination of the etching of the surface by atomic hydrogen and the interaction with carbon radicals and carbon atoms allows then the growth of SiC nanofibers. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High gain observed in X‐ray induced currents in synthetic single crystal diamonds
Authors: Lohstroh A. , Sellin P. J. , Boroumand F. , Morse J. 
Published: August 2007

AbstractDiamond is considered as tissue equivalent, due to its low atomic number, which makes it a particular attractive material for medical radiation dosimetry applications. X‐ray dosimeters made of natural single crystal diamonds are commercially available and routinely used, with typical gain values of about 0.5. The selection of suitable natural diamonds for this purpose is time and cost intensive. We report an X‐ray induced current study in synthetic single crystal diamonds. Similar to natural diamond dosimeters, the devices had to be pre‐irradiated before use to achieve a reproducible performance. We compare two chemical vapour deposited (CVD) samples grown by Element Six Ltd (UK). D1 was a high purity sample contacted in a sandwich structure with an asymmetric contact pair. Sample D2 was cut vertically and contained some nitrogen rich layers. It was contacted with two Ohmic contacts, which partly covered the high temperature/high pressure substrate material. Particle spectroscopy suggests better charge transport in D1 compared to D2, most likely caused by the lower purity. In contrast to this, large gain values up to 6 × 104 and a sensitivity of ∼30 mC/Gy were measured at field strengths of 2 kV/cm in D2, and only 7 µC/Gy in D1, despite their comparable volumes. We deduce that the gain observed in these devices is affected by the electrical properties of the metal‐diamond contacts. The response time of the high gain device was in the order of minutes, which is longer than expected by a purely photoconductive process. Long persistent currents have been reported before in diamond under UV irradiation and modifications of gain and response time by surface treatment of UV detectors are known in the literature, highlighting the influence of the surface and contact interface on the device operation. Our results indicate that synthetic single crystal diamond provides a promising material for high sensitivity tissue‐equivalent X‐ray dosimeters. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Antiobesity properties of two African plants (Afromomum meleguetta and Spilanthes acmella) by pancreatic lipase inhibition
Authors: Ekanem A. P. , Wang M. , Simon J. E. , Moreno D. A. 
Published: August 2007

AbstractEthanol extracts of seeds of Afromomum meleguetta and flower buds of Splilanthes acmella presented pancreatic lipase inhibitory activities in a concentration related manner under in vitro conditions. The two plants were extracted with 70% ethanol by sonication, fractionated on silica gel and tested at concentrations in the range 0.75–2.0 mg/mL. Lipase inhibitory activities of 90% and 40% were observed in A. meleguetta and S. acmella, respectively. The two plants have potentials as candidates for weight reduction and obesity control. Copyright © 2007 John Wiley & Sons, Ltd.
Hepatoprotective effect of leaf extracts of Andrographis lineata nees on liver damage caused by carbon tetrachloride in rats
Authors: Sangameswaran B. , Reddy T. Chandraganth , Jayakar B. 
Published: August 2007

AbstractThe present study was conducted to evaluate the hepatoprotective effect of Andrographis lineata (Acanthaceae) extracts in carbon tetrachloride‐induced liver injury in rats. Male Wistar rats with chronic liver damage, induced by subcutaneous injection of 50% v/v carbon tetrachloride in liquid paraffin at a dose of 3 mL/kg on alternate days for a period of 4 weeks, were treated with methanol and aqueous extracts of A. lineata orally at a dose of 845 mg/kg/day. The biochemical parameters such as serum glutamate oxaloacetate transaminase, serum glutamate pyruvate transaminase, serum bilirubin and alkaline phosphatase were estimated to assess the liver function. Histopathological studies of the liver were also carried out to confirm the biochemical changes. Histopathological examinations of liver tissue corroborated well with the biochemical changes. The activities of extracts were comparable to a standard drug. Hepatic steatosis, hydropic degeneration and necrosis were observed in the carbon tetrachloride treated group, while these were completely absent in the standard and extract treated groups. A. lineata extracts exhibited hepatoprotective action against carbon tetrachloride‐induced liver injury. The present investigation established pharmacological evidence to support the folklore claim that it is used traditionally as a hepatoprotective agent. Copyright © 2007 John Wiley & Sons, Ltd.
Schizandrin reverses memory impairment in rats
Authors: Egashira Nobuaki , Kurauchi Kouji , Iwasaki Katsunori , Mishima Kenichi , Orito Kensuke , Oishi Ryozo , Fujiwara Michihiro 
Published: August 2007

AbstractThe present study investigated the effect of schizandrin, a component of the fruit of Schizandra chinesis Baill (Fructus Schizandrae), on memory impairment in rats. Scopolamine (0.5 mg/kg, i.p.), a non‐selective muscarinic receptor antagonist, markedly impaired spatial memory in an eight‐arm radial maze. A higher dose of scopolamine (3 mg/kg, i.p.) also impaired the passive avoidance response. Schizandrin (1 and 10 mg/kg, p.o.) significantly reversed the scopolamine‐induced impairment of spatial memory. Similarly, schizandrin (1 mg/kg, p.o.) significantly reversed the scopolamine‐induced impairment of the passive avoidance response. Moreover, in mice, schizandrin (1 and 10 mg/kg, p.o.) enhanced tremors induced by oxotremorine, a muscarinic M1 receptor agonist. Taken together these findings suggest that schizandrin reverses scopolamine‐induced memory impairment, in part, by enhancing cholinergic function, and that schizandrin might be useful for treating memory deficits. Copyright © 2007 John Wiley & Sons, Ltd.
In vitro anti‐Helicobacter pylori activity of diallyl sulphides and protocatechuic acid
Authors: Liu Wen‐hu , Hsu Cheng‐chin , Yin Mei‐chin 
Published: August 2007

AbstractThe in vitro inhibitory effects of diallyl disulphide (DADS), diallyl trisulphide (DAT), roselle calyx extract and protocatechuic acid (PA) on the growth of Helicobacter pylori (15 susceptible, 11 clarithromycin‐resistant and 9 metronidazole‐resistant strains) were studied. The inhibition zone was determined after each agent had been heated at 25, 60, 100 °C for 60 min. The minimal inhibitory concentration (MIC) of each agent was determined by the tube dilution assay. The results showed that heat treatment did not affect the anti‐H. pylori activity of DADS, DAT, roselle calyx extract and PA, and the MIC values of these agents against test H. pylori strains were in the range 8–64 mg/L. The time‐kill study assay for DAT and PA at 1× MIC was monitored in Muller Hinton broth supplemented with 10% horse blood or mice stomach homogenate. Both DAT and PA inhibited the growth of all test H. pylori in broth and mice stomach homogenate (p < 0.05); however, the inhibitory effects of these two agents were less in mice stomach homogenate than in broth (p < 0.05). DAT at 4, 6, 8, 10, 12, 14 mg/L and PA at 8, 16, 24, 32, 40, 48 mg/L were used for urease activity assay. These two agents significantly reduced urease activity of test H. pylori strains (p < 0.05), in which DAT and PA at 1× MIC reduced the urease activity of H. pylori to 70% and 40%, respectively. These agents, based on their lower MIC values and heat tolerance, might be useful in the prevention or therapy of H. pylori. Copyright © 2007 John Wiley & Sons, Ltd.
Theanine prevents memory impairment induced by repeated cerebral ischemia in rats
Authors: Egashira Nobuaki , Ishigami Noriko , Pu Fengling , Mishima Kenichi , Iwasaki Katsunori , Orito Kensuke , Oishi Ryozo , Fujiwara Michihiro 
Published: August 2007

AbstractThe present study investigated the neuroprotective effect of γ‐glutamylethylamide (theanine), a component Japanese green tea (Camellia sinensis), on memory impairment induced by twice‐repeated cerebral ischemia in rats. Theanine was injected i.p. immediately after the first occlusion. Theanine (0.3 and 1 mg/kg) significantly prevented the impairment of spatial memory in rats subjected to repeated cerebral ischemia, 7 days after the second reperfusion. Moreover, theanine (1 mg/kg) significantly inhibited the decrease in the number of surviving cells in the hippocampal CA1 field in the same rats. These results suggest that theanine prevents memory impairment induced by repeated cerebral ischemia, in part by protecting against neuronal cell death, and that it might be useful for preventing cerebrovascular disease. Copyright © 2007 John Wiley & Sons, Ltd.
Dynamic dipole polarizabilities of the ground and excited states of confined hydrogen atom computed by means of a mapped Fourier grid method
Authors: Cohen S. , Themelis S. I. , Sen K. D. 
Published: August 2007

AbstractAccurate theoretical estimates of static and dynamic dipole polarizabilities are reported for the ground and excited states of hydrogen atom confined at the center of a spherical “box” with impenetrable walls using a novel theoretical algorithm that combines the variational–perturbation approach with an appropriately adapted mapped Fourier grid method and uniformly maintains the numerical accuracy. A variation of computed polarizabilities is observed as a function of the number of grid points. However, rapid convergence to their correct values, even far into the anomalous dispersion region, is achieved by an extrapolation procedure to the limit of an infinitely large number of grid points using a small number of the lowest‐order Padé approximants. It is shown that dipole polarizabilities strongly depend upon the electronic state and the radius of confinement. In particular, the static polarizability of 2s state changes sign under strong confinement. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008