bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Efficient Route to 4/5/6 Polycyclic β‐Lactams
Authors: Desroy Nicolas , Robert‐Peillard Fabien , Toueg Julie , Duboc Romain , Hénaut Charlotte , Rager Marie‐Noëlle , Savignac Monique , Genêt Jean‐Pierre 
Published: November 2004

AbstractThe synthesis of 4/5/6 polycyclic β‐lactams by enyne metathesis and Diels−Alder reactions is described. Compared to the synthesis of 4/6/6 and 4/7/6 polycyclic β‐lactams previously reported by our laboratory, formation of the strained 4/5/6 compounds requires alternative reaction conditions. Indeed, the synthesis of the 4/5 bicyclic diene 12 was more difficult than those of the 4/6 (13) and 4/7 (14) dienes. The strain of the 4/5 system could be observed by NMR spectroscopy and molecular modelling. Moreover, the reactivity of 4/5 diene 12 towards Diels−Alder cycloaddition was also different from that of the 4/6 (13) and 4/7 (14) dienes. Cycloadditions with 4/5 diene 12 therefore had to be performed in lithium perchlorate/diethyl ether (LPDE) or in an ionic liquid in order to proceed in good yields with various dienophiles. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
An Unusual Series of Thiomethylated Canthin‐6‐ones from the North American Mushroom Boletus curtisii
Authors: Bröckelmann Martin G. , Dasenbrock Johannes , Steffan Bert , Steglich Wolfgang , Wang Yuekui , Raabe Gerhard , Fleischhauer Jörg 
Published: November 2004

AbstractA unique set of thiomethylated canthin‐6‐one derivatives was isolated from Boletus curtisii. The bright yellow color of this mushroom is caused by two optically active canthin‐6‐one sulfoxides for which the names curtisin and 9‐deoxycurtisin are proposed. The structures of the new compounds were established by MS and NMR methods and the absolute configuration of the sulfoxides determined by quantum chemical calculations. This is the first occurrence of canthin‐6‐one alkaloids outside of higher plants. The chemotaxonomic implications of these findings are discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Blue light differentially alters cellular redox properties
Authors: Lewis Jill B. , Wataha John C. , Messer Regina L. W. , Caughman Gretchen B. , Yamamoto Tetsuya , Hsu Stephen D. 
Published: November 2004

AbstractBlue light (λ = 380–500 nm) historically has been used to initiate polymerization of biomaterials and recently has been proposed as a therapeutic agent. New evidence suggests that cell‐type–specific responses result from redox changes induced by exposure to blue light. Cultured cells were exposed to defined doses of blue light, equivalent to exposure times of 10 s and 2 min, to achieve energies of 5 J/cm2 and 60 J/cm2, respectively, after which (a) viable cell number, (b) cellular protein profiles, (c) mitochondrial succinate dehydrogenase (SDH) activity, (d) total reactive oxygen species (ROS), and (e) induction of apoptosis were compared to that of nonexposed control cultures. Results showed that blue‐light exposure arrested monocyte cell growth and increased levels of peroxiredoxins. SDH activity of normal epidermal keratinocytes (NHEK) was slightly enhanced by blue light, whereas identical treatment of OSC2 oral tumor cells resulted in significant suppression of SDH activity. Blue‐light exposure generally induced higher levels of total ROS in OSC2 cells than in NHEK. Finally, only OSC2 cells exhibited signs of apoptosis via Annexin V staining following exposure to blue light. These data support the central hypothesis that blue light induces an oxidative stress response in cultured cells resulting in cell‐type–specific survival outcomes. The identification of oxidative stress as a mediator of the effects of blue light is a critical first step in defining its biological risks and therapeutic opportunities. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 72B: 223–229, 2005
Antisense downregulation of SARS‐CoV gene expression in Vero E6 cells
Authors: Shi Yi , Luo Haifeng , Jia Jie , Xiong Jie , Yang Dehua , Huang Bing , Jin Youxin 
Published: November 2004

AbstractBackgroundSevere acute respiratory syndrome (SARS) is caused by a novel coronavirus (SARS‐CoV). It is an enveloped, single‐stranded, plus‐sense RNA virus with a genome of ∼30 kb. The structural proteins E, M and N of SARS‐CoV play important roles during host cell entry and viral morphogenesis and release. Therefore, we have studied whether expression of these structural proteins can be down‐regulated using an antisense technique.MethodsVero E6 cells were transfected with plasmid constructs containing exons of the SARS‐CoV structural protein E, M or N genes or their exons in frame with the reporter protein EGFP. The transfected cell cultures were treated with antisense phosphorothioated oligonucleotides (antisense PS‐ODN, 20mer) or a control oligonucleotide by addition to the culture medium.ResultsAmong a total of 26 antisense PS‐ODNs targeting E, M and N genes, we obtained six antisense PS‐ODNs which could sequence‐specifically reduce target genes expression by over 90% at the concentration of 50 µM in the cell culture medium tested by RT‐PCR. The antisense effect was further proved by down‐regulating the expression of the fusion proteins containing the structural proteins E, M or N in frame with the reporter protein EGFP. In Vero E6 cells, the antisense effect was dependent on the concentrations of the antisense PS‐ODNs in a range of 0–10 µM or 0–30 µM.ConclusionsThe antisense PS‐ODNs are effective in downregulation of SARS. The findings indicate that antisense knockdown of SARS could be a useful strategy for treatment of SARS, and could also be suitable for studies of the pathological function of SARS genes in a cellular model system. Copyright © 2004 John Wiley & Sons, Ltd.
PEGylated adenovirus vectors containing RGD peptides on the tip of PEG show high transduction efficiency and antibody evasion ability
Authors: Eto Yusuke , Gao Jian‐Qing , Sekiguchi Fumiko , Kurachi Shinnosuke , Katayama Kazufumi , Maeda Mitsuko , Kawasaki Koichi , Mizuguchi Hiroyuki , Hayakawa Takao , Tsutsumi Yasuo , Mayumi Tadanori , Nakagawa Shinsaku 
Published: November 2004

AbstractBackgroundPEGylation of adenovirus vectors (Ads) is an attractive strategy in gene therapy. Although many types of PEGylated Ad (PEG‐Ads), which exhibit antibody evasion activity and long plasma half‐life, have been developed, their entry into cells has been prevented by steric hindrance by polyethylene glycol (PEG) chains. Likewise, sufficient gene expression for medical treatment could not be achieved.MethodsA set of PEG‐Ads, which have different PEG modification rates, was constructed, and gene expression was evaluated using A549 cells. A novel PEGylated Ad (RGD‐PEG‐Ad), which contained RGD (Arg‐Gly‐Asp) peptides on the tip of PEG, was developed. We evaluated gene expression both in Coxsackie‐adenovirus receptor (CAR)‐positive as well as ‐negative cells, and in vivo gene expression was also determined. Furthermore, the antibody evasion ability and the specificity of infection exhibited by this RGD‐PEG‐Ad were also evaluated.ResultsWhereas PEG‐Ads decreased gene expression in CAR‐positive cells, RGD‐PEG‐Ad enhanced gene expression notably, to a level about 200‐fold higher than that of PEG‐Ads. Moreover, gene expression of RGD‐PEG‐Ad was almost equal to that of Ad‐RGD, which contains an RGD‐motif in the fiber and exhibits among the highest gene expression of CAR‐positive and ‐negative cells. Furthermore, although Ad‐RGD gene expression decreased remarkably in the presence of anti‐Ad antiserum, RGD‐PEG‐Ad maintained its activity against antibodies. In vivo experiments also demonstrated that the modification of Ads with RGD‐PEG induced efficient gene expression.ConclusionsIn the present study, we demonstrated that a new strategy, which combined integrin‐targeting the RGD peptide on the tip of PEG and modified the Ad using this material, could enhance gene expression in both CAR‐positive and ‐negative cells. At the same time, this novel PEGylated Ad maintained strong protective activity against antibodies. This strategy could also be easily modified for developing other vectors using other targeting molecules. Copyright © 2004 John Wiley & Sons, Ltd.
Relationship between atmospheric circulation types over Greece and western–central Europe during the period 1958–97
Authors: Anagnostopoulou Christina , Flocas Helena , Maheras Panagiotis , Patrikas Ioannis 
Published: November 2004

AbstractAn attempt is made to examine the relationship of the surface circulation prevailing over Europe with the corresponding surface and 500 hPa over Greece by correlating Lamb weather types for western Europe and Hess and Brezowsky (HB) types for central Europe with those derived from a new classification scheme for the Greek area. It was found that it was difficult to formulate rules controlling the frequency distributions of the circulation types over the Greek area in relation to the circulation over western and central Europe. However, statistically significant correlation was found between certain types with high frequency, which is greater between Lamb and HB types with the surface circulation types over the Greek area, compared with 500 hPa circulation types. For the most correlated pairs, seasonal composites of mean sea‐level pressure and 500 hPa geopotential height anomalies demonstrated that the formation of the circulation types over the Greek area depends on the extent, intensity of the anticyclonic or cyclonic centres, air mass characteristics, and stability profile in the lower troposphere over the regions examined, but especially over the central and eastern Mediterranean. Copyright © 2004 Royal Meteorological Society
The factors governing the summer regime of the eastern Mediterranean
Authors: Ziv Baruch , Saaroni Hadas , Alpert Pinhas 
Published: November 2004

AbstractThe synoptic scale features over the eastern Mediterranean (EM) for July–August are examined using National Centers for Environmental Prediction–National Center for Atmospheric Research reanalysis data. The region is subjected to two primary factors: mid–upper level subsidence and lower level cool advection, associated with the Etesian winds.The interdiurnal variations of these factors were found to be correlated with each other, with a maximum of r = 0.76, found between the 700 hPa subsidence and the 925 hPa wind speed. The impact of these factors on the temperature regime was examined through their contributions in the temperature tendency equation at 32.5°N, 35°E. A significant correlation was found between them at the 850 hPa level, indicating that they tend to balance each other. This explains the low interdiurnal temperature variations there in summer.Zonal‐vertical and isentropic cross‐sections indicate the existence of a closed circulation connecting the EM with the Asian monsoon, and a meridional‐vertical cross‐section indicates a signature of the Hadley cell across eastern North Africa. Air back‐trajectories demonstrate that the EM is connected at the lower troposphere with Europe, at the mid‐troposphere with eastern North Africa and at the higher troposphere with the Asian monsoon. Significant correlation was found between the interdiurnal variations in the upward motion over the Asian monsoon and the subsidence over the Levant, with a 1 day lag, implying that the Asian monsoon controls the interdiurnal variations over the Levant.A detailed analysis shows that the correlation between the two dynamic factors governing the EM results from a linkage existing between each one of them and the Asian monsoon. An intensification of the Asian monsoon enhances both the subsidence over the Levant, via the circulation connecting them, and the Etesian winds, due to the enhanced pressure gradient between the two regions. Copyright © 2004 Royal Meteorological Society
Interference effects of C2‐radicals in nitrogen vibrational CARS thermometry using a frequency‐doubled Nd:YAG laser
Authors: Malarski A. , Beyrau F. , Leipertz A. 
Published: November 2004

AbstractGenerally, in coherent anti‐Stokes Raman spectroscopy a frequency‐doubled Nd:YAG laser emitting at 532 nm along with a broadband dye laser is used for nitrogen vibrational CARS thermometry, resulting in a signal wavelength of 473 nm. Unfortunately, emission and absorption bands of C2 radicals occur in the same spectral region, hence the CARS signal can be disturbed by interferences. C2 radicals are an intermediate species especially in hydrocarbon flames and, moreover, they can be produced by laser‐induced vaporization of soot particles present in the flame. The described interferences can be a severe problem resulting in erroneous temperature data. The influence of the interferences on the determined temperatures was analyzed in this work. For this purpose, an experimental set‐up was chosen that simultaneously generates the vibrational nitrogen signal at 473 and 487 nm, i.e. in a undisturbed spectral region. This was realized by using the dual‐pump CARS technique with an annular phase‐matching geometry (USED CARS). Hence a direct comparison of temperature results from disturbed and undisturbed spectra can be performed. Measurements conducted in one‐dimensional ethylene–air flames established on a McKenna‐type burner are presented. Copyright © 2004 John Wiley & Sons, Ltd.
Chromatographic methods for the separation of biocompatible iron chelators from their synthetic precursors and iron chelates
Authors: Kovaříková Petra , Mokrý Milan , Klimeš Jiří , Vávrová Kateřina 
Published: November 2004

AbstractChromatographic methods have been developed for the separation of the three novel biocompatible iron chelators pyridoxal isonicotinoyl hydrazone (PIH), salicylaldehyde isonicotinoyl hydrazone (SIH), and pyridoxal 2‐chlorobenzoyl hydrazone (o‐108) from their synthetic precursors and iron chelates. The chromatographic analyses were achieved using analytical columns packed with 5 μm Nucleosil 120‐5 C18. For the evaluation of all chelators in the presence of the synthetic precursors, EDTA was added to the mobile phase at a concentration of 2 mM. The best separation of PIH and its synthetic precursors was achieved using a mixture of phosphate buffer (0.01 M NaH2PO4, 5 mM 1‐heptanesulfonic acid sodium salt; pH 3.0) and methanol (55 : 45, v/v). For separation of SIH and its synthetic precursors, the mobile phase was composed of 0.01 M phosphate buffer (pH 6.0) and methanol (60 : 40, v/v). o‐108 was analyzed employing a mixture of 0.01 M phosphate buffer (pH 7.0), methanol, and acetonitrile (60 : 20 : 20, v/v/v). These mobile phases were slightly modified to separate each chelator from its iron chelate. Furthermore, a RP‐TLC method has also been developed for fast separation of all compounds. The chromatographic methods described herein could be applied in the evaluation of purity and stability of these drug candidates.
Capillary electrophoretic and micellar electrokinetic separations of asymmetric dimethyl‐L‐arginine and structurally related amino acids: Quantitation in human plasma
Authors: Trapp Gabriele , Sydow Karsten , Dulay Maria T. , Chou Tina , Cooke John P. , Zare Richard N. 
Published: November 2004

AbstractWe report the development of efficient electrophoretic methods for the separation and quantification of L‐arginine and six naturally occurring derivatives that are structurally and functionally related. Capillary electrophoresis (CE) employing a concentrated borate buffer at pH 9.4 achieves the separation of mixtures containing dimethyl‐L‐arginine, N G‐monomethyl‐L‐arginine, L‐arginine, L‐homoarginine, L‐ornithine, and L‐citrulline as 4‐fluoro‐7‐nitrobenzofurazan derivatives. In addition, the separation of the isomeric dimethyl‐L‐arginine derivatives (symmetric and asymmetric) is attained with baseline resolution by micellar electrokinetic chromatography (MEKC) when a high concentration of deoxycholic acid is added as a surfactant to the same running buffer. The influence of buffer type, concentration, and pH on the separation was studied to optimize separation conditions. The limit of quantitation (LOQ) for asymmetric dimethyl‐L‐arginine in aqueous solution was determined to be 20 μM using UV absorption in a CE separation and 0.1 μM using laser induced fluorescence (LIF) detection in an MEKC separation. This newly developed method was successfully applied for the quantitation of asymmetric dimethyl‐L‐arginine and L‐arginine in human plasma samples at levels that might be used as a clinical diagnostic for cardiovascular disease (0.125 μM LOQ).
Significant Role of Bacterial Undecaprenyl Diphosphate (C55‐UPP) for Rubber Synthesis by Hevea Latex Enzymes
Authors: Rattanapittayaporn Atiya , Wititsuwannakul Dhirayos , Wititsuwannakul Rapepun 
Published: November 2004

AbstractSummary: Washed bottom fraction (BF) membrane‐bound particles of centrifuged fresh Hevea latex were found to be very active in rubber biosynthesis (RB). The washed BF membrane (WBM) showed higher RB activity and is strongly stimulated by anionic surfactants – more by DOC than SDS. WBM enzymes system can synthesize rubber either with allylic isoprenes (higher RB) or without (lower RB). Washed rubber particles (WRP), used generally in RB assays, had very low RB activity compared to the much higher activity observed for WBM. Bacterial undecaprenyl diphoshate (C55‐UPP) was very active allylic initiator for rubber synthesis by WBM. Comparisons of allylic UPP with the shorter ones (C15‐FPP, C20‐GGPP) showed that UPP was the most effective. WBM activity orders were UPP ≫ GGPP > FPP. The DOC activated WBM synthesized less polyprenyl intermediates (butanol extractable) but more final rubber product (toluene/hexane extract), different than FPP and GGPP. WBM enzymes were highly versatile in using diverse different allylics, but UPP was most preferable. WRP was found a little active for UPP with DOC, but still much lower than WBM. Rubber product analysis by RP‐TLC with acetone/hexane solvent system showed that WBM was mostly rubber, but WRP was mainly the intermediates. Quantitative analysis showed that WBM labeled rubber was confined to the origin spot, different than WRP as mainly labeled intermediates. It was thus confirmed that the WBM plays the key role in RB functions, and not WRP as mostly reported. WBM served as the actual rubber synthesis site, and bacterial UPP was very good RB initiator.
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Reinvestigation of the Mechanism of the Free Radical Polymerization Photoinitiation Process by Camphorquinone–Coinitiator Systems: New Results
Authors: Pyszka Ilona , Kucybała Zdzisław , Pączkowski Jerzy 
Published: November 2004

AbstractSummary: Comparative studies of photoinitiation processes using camphorquinone (CQ) and benzophenone (BP) as light absorbers were performed. The experimental results show that after the transformation of (phenylthio)acetic acid (PTAA) into its tetrabutylammonium salt (PTAA AS), a substantial decrease of the polymerization photoinitiation ability for the CQ–PTAA AS pair in comparison to the CQ–PTAA pair is observed. The mechanism of the photoinitiated polymerization for the tested photoredox pair was clarified based on laser flash photolysis experiments obtained using benzophenone as an electron acceptor and (phenylthio)acetic acid and its tetrabutylammonium salt as electron donors in solution in MeCN. It is documented and deduced that the photoreduction of benzophenone in the presence of (phenylthio)acetic acid and its tetrabutylammonium salt occurs by a photoinduced electron transfer process, while for CQ as initiator, the free radicals are formed by hydrogen atom abstraction by the triplet state of camphorquinone.Schematic of the transients formed after an electron‐transfer process for benzophenone–PTAA and benzophenone–PTAA AS pairs.magnified imageSchematic of the transients formed after an electron‐transfer process for benzophenone–PTAA and benzophenone–PTAA AS pairs.
Endothelin receptor expression in human lungs of newborns with congenital diaphragmatic hernia
Authors: de Lagausie Pascal , de Buys‐Roessingh Anthony , Ferkdadji Latifa , Saada Julien , Aisenfisz Sophie , Martinez‐Vinson Christine , Fund Xavier , Cayuela Jean Michel , Peuchmaur Michel , Mercier Jean Christophe , Berrebi Dominique 
Published: November 2004

AbstractCongenital diaphragmatic hernia (CDH) is a major cause of refractory respiratory failure in the neonatal period and is characterized by persistent pulmonary hypertension of the newborn (PPHN) and pulmonary hypoplasia. Endothelin‐1 (ET‐1) dysregulation may play a significant role in the pathophysiology of PPHN and ET‐1 acts through binding to type A (ETA) and type B (ETB) receptors. Therefore, ETA and ETB receptor protein expression was studied using immunohistochemistry in 10 lung specimens obtained from newborns with CDH, and 4 normal lung specimens, in order to explore whether dysregulation of ETA and ETB expression contributes to PPHN. ETA and ETB mRNAs were then quantified using real‐time RT‐PCR in laser‐microdissected pulmonary resistive arteries. In the lungs of newborns with CDH, immunohistochemistry of both ETA and ETB receptors demonstrated over‐expression in the thickened media of pulmonary arteries. Using laser microdissection and real‐time RT‐PCR, higher levels of ETA and ETB mRNA were found in CDH pulmonary arteries than in controls: this increase was more pronounced for ETA mRNA. This study provides the first demonstration of ET‐1 receptor dysregulation in association with structural alteration of pulmonary arteries in newborns with CDH and PPHN. This dysregulation preferentially affects the ETA receptor. These results suggest that dysregulation of ET‐1 receptors may contribute to PPHN associated with CDH. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Bone marrow cells engraft within the epidermis and proliferate in vivo with no evidence of cell fusion
Authors: Brittan Mairi , Braun Kristin M , Reynolds Louise E , Conti Francesco J , Reynolds Andrew R , Poulsom Richard , Alison Malcolm R , Wright Nicholas A , Hodivala‐Dilke Kairbaan M 
Published: November 2004

AbstractIn adults, bone marrow‐derived cells (BMDC) can contribute to the structure of various non‐haematopoietic tissues, including skin. However, the physiological importance of these cells is unclear. This study establishes that bone marrow‐derived epidermal cells are proliferative and, moreover, demonstrates for the first time that BMDC can localize to a known stem cell niche: the CD34‐positive bulge region of mouse hair follicles. In addition, engraftment of bone marrow cells into the epidermis is significantly increased in wounded skin, bone marrow‐derived keratinocytes can form colonies in the regenerating epidermis in vivo, and the colony‐forming capacity of these cells can be recapitulated in vitro. In some tissues this apparent plasticity is attributed to differentiation, and in others to cell fusion. Evidence is also provided that bone marrow cells form epidermal keratinocytes without undergoing cell fusion. These data suggest a functional role for bone marrow cells in epidermal regeneration, entering known epidermal stem cell niches without heterokaryon formation. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.